WO1984000993A1

WO1984000993A1 - Rotary machine

Info

Publication number: WO1984000993A1
Application number: PCT/US1983/001244
Authority: WO
Inventors: Edward Charles Mendler Iii
Original assignee: Edward Charles Mendler Iii
Priority date: 1982-08-26
Filing date: 1983-08-15
Publication date: 1984-03-15
Also published as: EP0118508A1

Abstract

Rotary machines (10) of the type having a fluid chamber (60) of changing volume, e.g. as in an engine or pump, in which two rotors (50, 52) rotate in the same direction; a cylindrical surface (CL) of the first rotor of substantial arcuate extent, of radius substantially equal to the radius (R) of its bore (36, 38), is arranged for sealing relationship throughout a chamber-defining range of rotation, with both its bore wall (27, 39; 25, 37) and with a surface of the second rotor; and the surface (TL, TF) of the second rotor has a progressively changing radius to cause the chamber volume to progressively change during rotation. For forming multiple chambers, each subject to successive compression and expansion, each of the rotors has a transition surface (TL) preceding its large cylindrical surface (CL) and a transition surface (TF) following its large cylindrical surface, with an apex seal (82) formed at each end of each large cylindrical surface. Preferably a small cylindrical surface (CS) on each rotor between the two transition surfaces seals against the large cylindricalsurface (CL) of the other rotor during rotation. Useful in other machines as well, the rotor carries movable sealing members (82, 84) which apply against an opposed surface sealing pressure that decreases in magnitude with increase in rotational velocity, with restraint (1102) to control sealing movement. Other sealing configurations (1022) are described. Also a variable member (1002) defining part of the bore surface is movable relative to the rotor by means responsive to desired operating conditions to vary the point where the rotor and surface begin or end a sealed relationship.

Description

ROTARY MACHINE Background of the Invention The invention relates to rotary machines that have a fluid chamber of changing volume, as in an engine or a pump.

Rotary machines of this type employ a rotating surface to have a working relationship with a fluid, e.g. compression or expansion. In the case of an engine, the machine also generates shaft energy as where a compressed gas and fuel mixture is ignited for explosive expansion within the chamber of the machine. Prior rotary machines have typically employed one eccentric rotor or multiple adjacent rotors that turn in opposite directions so that adjacent rotor surfaces move in the same direction; however, machines having rotors turning in the same direction have been suggested.

Summary of the Invention In detail, the invention applies to a rotary machine that cyclically defines a chamber of progressively changing volume by means of a pair of co-acting rotors. The rotors are mounted for dependent rotation on parallel axes of adjacent cylindrical bores formed in a block, the axes being spaced apart a αistance less than the sum of the radii of the bores. The rotors have surfaces adapted to provide a progressive rotor-to-rotor seal while each rotor also forms a rotor-to-bore-wall seal and face-to-end-closing surface seals, the rotor surfaces in cooperation with the other surfaces of the machine defining the chamber of changing volume.

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CMFI According to this aspect of the invention, in combination, the rotors rotate in the same direction, a cylindrical surface of the first rotor, of radius substantially equal to the radius of its bore and having substantial arcuate extent, is arranged in sealing relationship with its bore wall and with a surface of the second rotor, at least part of the surface of the second rotor exposed to this chamber has a progressively changing raαius to cause the chamber volume to progressively change during rotation, and the rotor surfaces are constructed to avoid interfering contact.

In preferred embodiments, the cylindrical surface of the first rotor ends at an apex adapted to form the seal with the chamber-sounding surface of the second rotor, and the second rotor defines a transition surface which extends from the point of minimum radius at which the apex portion forms a seal therewith, through a curve of increasing radius, to a point having radius corresponding substantially to the radius of the second bore, the curve being shaped to correspond substantially to the path of the apex of the first rotor over the extent of the progressive rotor-to-rotor seal. With this relationship, during rotation, the apex of the first rotor moves in sealing relationship along the transition surface of the second rotor, and the volume of the chamber progressively changes as a result of movement of the transition surface relatively toward or away from the cylindrical surface. To decrease the volume of the chamber, the direction of rotation causes the transition surface to move relatively toward the cylindrical surface while the apex moves to points of increasing radius along the curve of the transition surface. To increase the volume of the chamber the direction of motion is in the opposite direction. In the case of a power generator, e.g. where the chamber comprises an expansion chamber, for a steam or internal combustion engine, the transition surface of the second rotor is adapted to transform the expansive force of the contained gas into shaft energy.

In many cases, an intake or an exhaust flow path is defined by cooperative opposed surfaces of one of the rotors and the block during rotation of the rotors. In the case of intake flow, the path is typically formed prior to the formation of the respective rotor-to-bore-wall seal and in many cases is associated with a source of pressurized fluid which forces the fluid through the path. In some preferred cases, an inflow path and an outflow path are formed simultaneously at different sides, to establish a through-flow of fluid through the space in which the chamber is to be formed. In the case of a compression chamber of an internal combustion engine, such simultaneous flow paths enable through-flow of air to scavenge combustion gases from the region, to cool the working surfaces of the engine and to provide combustion air to the chamber for the next cycle. In such cases a stationary surface that bounds the chamber when the volume of the chamber is reduced includes fuel injection and/or ignition means.

In the case of an expansion machine, such as a vacuum pump, preferably the intake means comprises an inlet port to enable flow of fluid into the chamber while the chamber expands.

In the case of a compressor or pressure pump, an exhaust means provides for outward flow of pressurized fluid from the chamber while the chamber decreases in volume. In detail of another aspect, the invention applies to a rotary machine which comprises a rotor and means defining a bore surface with which the rotor is arranged to interact to cylically define a fluid chamber during rotor rotation.

According to the invention, a variable member defining a portion of the bore surface is movable toward and away from the rotor in the manner to vary the rotational position of a transition point at which a sealed relationship between the rotor and the bore surface begins or ends, and means responsive to desired operating conditions to vary the position of the variable portion thereby to vary the rotational position of the point at which the sealed relationship begins or ends.

In preferred embodiments, the rotary machine is in the form of a rotary internal combustion engine in which the rotor and bore surface are cooperatively constructed to form at least part of a combustion chamber, the variable member defining with the rotor the point where the volume of the combustion chamber is first closed, variation in the position of the member serving to vary the compression ratio of the engine; and the bore surface is comprised in part of a relatively stationary first bore surface segment of radius which progressively enlarges relative to the radius of the rotor at points at progressively greater arcuate distance about the rotor axis from the point of the segment which lies closest to the rotor, the variable member defining a second bore surface segment which is movable outwardly relative to the first segment and has a transition end portion disposed closely adjacent to the relatively stationary segment, the transition end portion being movable along the first bore surface segment as the variable member moves outwardly from the rotor axis to expose an increasing amount of the first bore surface segment, preferably the variable member is pivotable about a pivot axis lying directly outwardly from the first bore surface segment and, the first bore surface segment is cylindrical, centered on the pivot axis, more preferably the second bore surface segment defined by the variable member is an arcuate surface of radius substantially equal to the radius of the rotor, and the machine further includes a flexible fairing member disposed at the outward end of the variable member, and a positioning means adapted to selectively position the variable means.

In a further preferred embodiment, the invention applies to a rotary machine that cyclically defines a chamber of progressively changing volume by means of a pair of co-acting rotors. The rotors are mounted for dependent rotation on parallel axes of aαjacent cylindrical bores formed in a block, the axes being spaced apart a distance less than the sum of the radii of the bores. The rotors have surfaces adapted to provide a progressive rotor-to-rotor seal while each rotor also forms a rotor-to-bore-wall seal and face-to-end-closing-surface seals, the rotor surfaces in cooperation with the other surfaces of the machine defining the chamber.

According to the invention of this preferred embodiment, in combination, the rotors rotate in the same direction, a cylindrical surface of the first rotor, of radius substantially equal to the radius of its bore and having substantial arcuate extent, is arranged in sealing relationship with its bore wall and with a surface of the second rotor, at least part of the surface of the second rotor exposed to this chamber has a progressively changing radius to cause the chamber volume to progressively change during rotation, and the rotor surfaces are constructed to avoid interfering contact. In the case of a machine in which the chamber has successive compression and expansion stages, as in an internal combustion engine, on the second rotor the transition surface (upon which the apex of the first rotor formed a seal during the compression stage) is followed by a large cylindrical surface, and on the first rotor the large cylindrical surface is followed by a transition surface. A second seal-forming apex is defined between the transition and cylindrical surfaces on the second rotor. Thus as the rotors continue their rotation after decreasing the chamber volume, the apex of the second rotor moves into sealing relationship along the trailing transition surface of the first rotor, while this transition surface moves apart from the cylindrical surface of the second rotor, to cause the volume of the chamber to expand. In a preferred form for forming multiple chambers, each subject to successive compression and expansion, each of the rotors has a transition surface preceding its large cylindrical surface and a transition surface following its large cylindrical surface, with an apex formed at each end of each large cylindrical surface. Different sets of surfaces and apexes, during different stages of rotation, thus can form chambers.

In many preferred cases, for both expansion and compression machines and in machines having combinations of such stages, to enable a chamber to be formed for an extended duration of rotation of the rotors, and to provide large ratio between smallest and largest volume of the chamber, the second rotor has a minor cylindrical surface beyond the small end of the transition surface, of radius substantially equal to the difference between the length of the line of centers of the rotors and the radius of the cylindrical surface of the first rotor. This minor cylindrical surface is arranged to be at the line of centers when the large cylindrical surface of the first rotor is at the line of centers, thereby to form a seal.

In one preferred case, the rotors are of identical size and shape with all of the features mentioned above and rotate at the same speed to form a pair of spaced-apart chambers.

In preferred embodiments of the foregoing machine, the sealing members^' at each apex are adapted to apply against the opposed surfaces outward sealing pressure that decreases in magnitude with increase in the velocity of rotation. To achieve this action, preferably the rotor-contacting surface of the sealing member is free to move in response to intertial effects. Preferably, the sealing member is free to slightly swing between first (rest) and second (high speed) positions about a pivot region that is positioned inwardly from the periphery of the rotor, the pivot region being offset from a radius of the rotor that projects to the center of mass of the sealing member.

By novel selection of the position of the center of mass of the sealing member, relative to the radius leading to the contact surface of the sealing member and the radius through the pivot axis, the motion of the sealing surface can be made to be mostly tangential or mostly radial depending upon the needs of the particular embodiment. In preferred embodiments of the sealing member: it is a rigid element extending outwardly from a rotating pivot bearing, the sealing member being biased toward the first position by an indepndent spring means, or is a cantilever spring portion capable of flexing generally in the pivot region in response to centrifugal effects; the force of the spring is progressively overcome by centrifugal effects as the rotor increases in speed; and in the preferred rotary machine of the invention, the second (high speed) position of the sealing surface relative to the first position is positioned tangentially in the direction of the major cylindrical surface of its rotor and away from its transition surface. A further important feature of the invention is that the described sealing member, at a given speed of rotation of tne rotor, can oe constructed and arranged to bear against the transition surface with pressure normal to the transition surface which varies generally inversely with change of volume of the chamber.

According to anotner aspect of the invention, the sealing member described above may be used in conjunction with any rotary device to form a seal with an opposed surface, the seal being constructed and arranged, preferably as earlier described, to respond to rotational speed to relieve sealing pressure as speed increases.

In another aspect, the invention applies to a rotary machine which comprises a rotor, means defining a complementary, opposed surface, and a sealing member bodily carried by the rotor member and movable with respect to the rotor member toward the complementary surface to form a seal therewith, the point of sealing of the sealing me Der progressing about the surface as the rotor rotates.

OMPI According to this aspect of the invention, restraint means are responsive to increase in the rotational rotor speed to apply increased restraint on the freedom of relative motion of the sealing member toward the surface thereby to enable decrease or elimination of direct pressure contact between the sealing member and the surface upon increased rotor speed.

In preferred embodiments of this aspect of the invention, the restraining means comprises a restraint member carried by the rotor and defining a friction brake surface engageable with the sealing member in a manner to restrain movement of the seal member, the restraint member being responsive to increase in centrifugal force attributable to increased speed of rotor rotation, to increase the pressure of engagement of the friction brake surface upon the sealing member, thereby to increase the restraint of the sealing member, preferably the sealing member comprises a member having a rotary bearing surface bearing upon a corresponding surface defined by the rotor, the sealing member extending from and rotable with the rotary bearing surface to move into sealing engagement with the complementary surface, the restraint member comprising a member lying inwardly of the sealing member, the restraint member having a surface engaged for relative motion with a corresponding surface of the sealing member, the restraint member being constrained against rotation with the sealing member and disposed to respond to increase in centrifugal force to engage the sealing member with increased pressure, thereby to frictionally restrain rotation of the sealing member toward the complementary surface. In a further aspect, the invention applies to a rotary machine which comprises a rotor and means defining relatively stationary surfaces with which the . rotor is arranged to interact to cyclically define a fluid chamber during rotor rotation.

According to this further aspect of the invention, the rotor includes a seal means for providing a sealing relationship with a complementary stationary chamber surface during rotary motion of the rotor, the seal means being comprised of at least one sealing member carried on the rotor and defining a sealing surface disposed in face-to-face relationship with the complementary surface, the bias means between the member and the rotor adapted to bias the sealing member toward the complementary surface, the bias means having a biasing portion with at least a component lying perpendicular to the radius of the rotor and a point of attachment spaced from the biasing portion, which is adapted and configured to apply a biasing force to the sealing member toward said complementary surface, the dimensional extent of the biasing portion in a direction perpendicular to the radius of the rotor at a first speed of rotation being different from the dimensional extent at a second speed of rotation, the biasing portion adapted to move elastically between positions at first and second speeds of rotation in response to increase of centrifugal force thereon, the biasing force applied by the biasing portion to the sealing member varying with variation in dimensional extent. in preferred embodiments of this further aspect, the bias means is a corrugated, relatively flat, resilient memDer attached to the rotor at a point along the length of the bias means inward of the center of mass of the bias means, the outer end of the bias means

OMPI having a dimensional component perpendicular to a radius of the rotor, whereby, due to said perpendicular dimensional component, the bias means, when the rotor is at rest, biasing a sealing member toward a complementary stationary surface, and when the rotor is rotating at a different, higher speed, the outer end of the bias means is urged radially outward by centrifugal force thereby reducing its perpendicular dimensional component and reducing the biasing force of the bias means toward the sealing member, and the sealing member comprises a plurality of flat sealing members disposed in axially superposed relationship, there being bias means between each pair of said flat sealing members and between said rotor and its adjacent said flat sealing member, adapted to bias the respective members apart, whereby the total clearance is divided between a plurality of small, flow-resistant gaps.

In still another important aspect of the invention, end seals for the machine comprises substantially flat seal elements disposed on the rotor in face-to-face relationship with the end-closing surface of the bore, with means between the seal and the rotor to bias the seal element toward the end closing surface. in preferred embodiments of this aspect of the invention, a surface of the seal defines at least one recess whereby fluid passing from a zone of high pressure to a zone of lower pressure across the seal surface encounters an enlarged volume with pressure of intermediate magnitude, the seal surface adapted to isolate the recess to maintain the pressure therein at the intermediate magnitude. Preferably a plurality of isolated recesses are provided to be encountered successively by the passing fluid, the pressure in the

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OMPI sfay. WIPO i_RNATX recesses being of progressively decreasing magnitude from the region of high pressure to the region of lower pressure along the fluid path. In some instances, a recess is provided in a fluid path across a surface remote from the sealing surface, the fluid under pressure in this recess being effective to bias an overlying seal toward the end surface; preferably recesses defined on different surfaces are connected axially through the seal, whereby the pressures in the recesses can be nearly balanced to maintain equal sealing effectiveness through the various axial gaps. In some cases it is advantageous to employ a plurality of substantially flat sealing members, in face-to-face relationship to divide the total clearance gap in the axial direction into a plurality of smaller clearance gaps, thereby to increase the effective viscous resistance to leakage flow and thus reduces leakage.

In detail of a still further aspect of the invention, a machine comprises a moving element and means defining a fixed surface with which the moving element is arranged to interact to cyclically define a fluid chamber during movement of the element, a surface of the element and the fixed surface adapted to be disposed in close-mated relationship to retard movement of fluid therebetween between the fluid chamber and an area of different pressure.

According to this aspect of the invention, a multiplicity of grooves defined in a fixed surface are configured-and arranged to permit fluid moving between surfaces in close-mated relationship from a first area of relatively high pressure to a second area of relatively lower pressure to pressurize the grooves in progression from the first area toward the second area. and the grooves defined in the fixed surface are configured and arranged to provide that movement of element surface in close-mated relationship with the fixed surface is adapted to progressively expose the grooves to the fluid chamber, whereby as leakage of fluid between the close-mated surfaces from the area of relatively higher pressure to a first groove defined in the fixed surface adjacent to the area of relatively higher pressure increase the pressure therein, movement of the element causes the first groove to be exposed to the area of higher pressure, thereby increasing the sealing performance of the close-mated surfaces.

Preferred Embodiment The structure and operation of certain preferred embodiments of the invention will now be described, after describing the drawings. Drawings

Fig. 1 is a cross-sectional view of a segment of a preferred internal combustion engine according to the invention taken on line 1-1 of Fig. 3 showing the rotors full rather than in cross-section;

Fig. la is a similar view of an engine with variable compression ratio taken at the line la-la of Fig. 3a; Fig. lb and lc are diagrammatic views of the engine of Fig. la at different compression ratios;

Fig. Id is a view similar to that in Figs. 1 and la of another variable compression engine construction; Fig. 2 is an axial cross section taken on line

2-2 of Fig. 1, again showing the rotors full rather than in cross-section, and also showing part of a second segment of the engine without rotors;

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OMPI Fig. 2a is a similar view of the engine having variable compression, taken at line 2a-2a of- Fig. 3a;

Fig. 3 is a diagrammatic side view partially in section of a complete engine having six segments in accordance with Fig. 1;

Fig. 3a is a diagrammatic side view partially in section of a two-chamber engine block with variable compression;

Fig. 4 is a cross-sectional view taken on line 4-4 of Fig. 3 showing gearing of the rotor shafts;

Figs. 5 through 5f depict the engine segment of Fig. 1 showing the rotors in the various phases of operation of an upper chamber, from intake through exhaust; Fig. 6 is an isometric view of a rotor removed from the engine, not showing spline teeth or labyrinth grooves;

Fig. 7 is a side view of an apex seal employed in the rotor of Fig. 6; Fig. 7a is an axial view in section of the bias spring of the apex seal, taken on line 7a-7a of Fig. 8, the apex seal and spring being shown in full;

Fig. 8 is a diagrammatic plan view partially in section of the apex seal of the rotor of Fig. 6 acting upon the surface of the mating rotor;

Fig. 8a is a similar view of an apex seal with restraining means, while Fig. 8b is a side plan view of the seal with restraining means;

Fig. 9 is a diagrammatic view of the apex seal of Fig. 8, suggesting its movement in use;

Fig. 9a is a free body diagram of the apex seal member of Fig. 8;

Fig. 10 is a plan view on enlarged scale of a single rotor of Fig. 1, omitting the spline teeth, while Figs. 11 and 12 are partial axial cross-sectional views taken on lines 11-11 and 12-12 respectively, of Fig. 10; Fig. 10a is a plan view of a rotor cut away to show the bias means, Fig. 10b is a force diagram, while Figs. 11a and 12a are partially axial cross-sectional views taken on lines lla-lla and 12a-12a respectively of Fig. 10a;

Fig. lib is view similar to Fig. 11a of an alternative embodiment; Figs. 12b and 12d are enlarged representation views of the opposed rotor and fixed bore wall seals with the leak retarding system of Fig. lb, while Figs. 12c and 12e are bar graph representations of the pressures in Figs. 12b and 12d, respectively; Fig. 13 is a cross-sectional view similar to

Fig. 1 of another preferred embodient employing three rotors;

Fig. 14 and 15 are views of an identical pump structure adapted, respectively, by virtue of opposite rotation, to compress or expand the chamber; Figs. 16 through lβc are sequential diagrammatic views of the preferred embodiment of a liquid pump having stages creating suction and pressure; Fig. 17 is a cross-sectional view of a further embodiment employing rotors of unequal size but of identical revolutionary speed;

Fig. 18 is a cross-sectional view of a three rotor machine employing small outer rotors and a larger central rotor which rotates at one half the speed of the outer rotors;

Fig. 19 is a top section view showing an alternate apex seal construction; and

Fig. 20 is a diagrammatic view of an alternate embodiment of a biased force seal, while Figs. 21 and 22 are side views taken at the lines 21-21 and 22-22, respectively thereof. Structure and Operation

Referring to Figs. 1 through 4, engine block 10 is comprised of block segments 12 and 14, gear-and-bearing segments 16 and bearing segments 18. Power shafts 20 and 20' extend from respective ends of block 10.

Referring to Figs. 1 and 3, the exhaust and intake manifolds 22 defining exhaust passages 24 and intake passages 26 on each side of the block are formed by unitary castings which extend substantially throughout the combined height of segments 12 and 14 of block 10 and service the combustion chambers formed in these block segments. Fuel injection port and/or ignition means 28 for each segment is shown in the center. Bolts 30 extend through the block and hold the segments together. Bolts 31 extend through blocks 16 and 18 for the same purpose. Block segment 12, shown in Fig. 1, is provided with holes for bolts 30 and additional holes 34 for bolts which terminate within the segments 16, further serving to hold the block segments together.

Each block segment 12 defines first and second adjacent cylindrical bores 36 and 38 formed in the block segment about parallel axis A and B. As shown in Figs. 1, 2 , each block segment has a single end plate 42, with opposite surfaces 40, 40' of this end plate closing the bores formed in adjacent block segments. The central block segment 14 is identical to block segment 12, except it has two sets of rotors with an intervening dividing plate 42' serving to close one side of the bores for each set of rotors. The bores in the block segments at respective ends of the block are closed by additional closing plates 44. Referring to Figs. 1 and 2, the bores 36 and 38 on axes A and B are defined in each block segment 12, and on each side of block segment 14. In this preferred embodiment the bores have equal radius R and the axes of the bores are spaced a distance D apart, D being less than the sum of the radii of the adjacent bores, i.e. less than 2R. Typically for a small engine R may be 2 inches and D may be 3 inches. First and second rotors 50 and 52, respectively, are closed in bores 36 and 38, on fixed axes A and B respectively, and splined in identical angular position to rotor shafts 46 and 48, respectively, extending along those axes. (Shafts 46 and 48 are shown bored for oil feed lines.)

The rotor surfaces are specially constructed to form progressive rotor-to-rotor seals between the two rotors while each rotor also forms a rotor-to-bore-wall seal with the wall of its respective bore, these rotor surfaces adapted to serve as bounding surfaces in cooperation with relatively stationary surfaces of the bores to define chambers of changing volume.

Referring to Fig. 10, this relationship is realized by major and minor cylindrical surfaces, C_L and C_s, respectively, each centered on the axis A of the rotor, and diametrically opposed, these surfaces being joined by cylindrical transition surfaces, T. and T„, which are centered about points spaced from the axis of the rotor. The major and minor cylindrical surfaces have an equal arcuate extent, and the joining transition surfaces on each of the rotor similarly have equal arcuate extent . In the present embodiment, where the rotors are of identical size and designed to turn at identical speed, the center for each transition surface, of radius R_, is located at the apex, A_, formed at the intersection of the major cylindrical

OMPI ^&/?NAT10 surface and the opposed transition surface. The minor cylindrical surface, C_g, has a radius substantially equal to the difference between the length of the line of centers of the rotors, D, and the radius, R, of the major cylindrical surface of the adjacent rotor.

In Figs. 5 through 5f, engine segment 12 of Fig. 1 is shown in reduced scale through a sequence of stages. Rotors 50, 52 rotate in a clockwise direction from the stage of flow of air through the engine prior to the combustion reaction in the upper chamber (Fig. 5) to the flow-through of air following combustion (Fig. 5f) . The air removes exhaust gas f om the upper chamber after combustion, cools internal surfaces of the engine and provides combustion air for the next cycle. Referring now to Fig. 5, rotors 50, 52 in conjunction with surfaces 37, 39 of cylindrical bores 36, 38, respectively, and intervening surface 35 form a flow-through passage (shown by arrows) for cooling air from intake 26 to exhaust 24, which is supplied, e.g., by a blower (not shown). Fig. 5a shows rotors 50, 52 after clockwise rotation. Rotor 52 closes intake 26, while rotor 50 closes exhaust port 24 to form closed chamber 60, the coaction of the rotors trapping a volume of the flowing fluid within the chamber, which is defined by the leading transition surface, T,, of rotor 52, the large cylindrical surface, C_L, of rotor 50, the cylindrical surface 39 of chamber 38, and the intervening surface 35 joining cylindrical surfaces 37, 39 of bores 36, 38. At this point, i.e. early in the compression stage, the small cylindrical surface, C_s, of rotor 52, contacts the large cylindrical surface of rotor 50, closing chamber 60.

Referring now to Fig. 5b, rotors 50, 52 have rotated to decrease the volume of chamber 60, by the relative motion of leading transition surface, T_L, on rotor 52 moving toward to large cylindrical surface, C_τ , of rotor 50, compressing the fluid in the chamber. (Surface C,, being progressive parts of a constant diameter cylinder centered on axis A does not affect the volume of chamber 60 during this compression stage.) At this point, the seal between the two rotors is formed by the trailing apex seal, A__F, of rotor 50 contacting the leading transitional surface T_ of rotor 52. Between the rotor positions in Fig. 5a and

Fig. 5b, rotor 50 has come out of contact with the minor cylindrical surface, C_s, and into contact with the transition surface T_L of rotor 52. As the apex seal contacts the opposed transition surface the critical compression stage begins.

Referring now to Fig. 5c, rotors 50, 52 have rotated to top center position and chamber 60, now formed by the major cylindrical surfaces, C,, of both rotors and by the intervening surface 35 that joins the cylinder bores, is at minimum size and the contained fluid is at maximum compression. In the combustion engine, fuel is injected prior to this point and the air-and-fuel mixture compressed in the chamber is ignited. The inertia of the spinning rotors carries the rotors through the compression phase to the point of maximum compression (Fig. 5c) .

Referring to Fig. 5d, expansion of chamber 60, now formed by major cylindrical surface, C-, of rotor

52 and the following transitional surface, Tt„, of rotor 50, begins. The seal between the rotor surfaces is made by the leading apex seal A_pL, of rotor 52 against the following transition surface, T , of rotor 50. The chamber is further defined by the intervening surface 35 and the cylindrical surface 37 of chamber 36. Expansion of the combusted gas acts against the following transitional surface, T_F, of rotor 50 to urge it to rotate about axis A, transmitting power through shaft 46 to power shaft 20 via gears 62, 64. In Fig. 5e, chamber 60 has been expanded by rotation of the rotors to nearly maximum size, which typically can be larger than the compression chamber. The leading apex seal of rotor 52 has moved out of contact with the surface of rotor 50. The sealing contact in this area now being between the major cylindrical surface, C,, of rotor 52 and the minor cylindrical surface, C-, of rotor 50.

It should be noted that the ratio of compression to expansion depends upon the arcuate locations of the points where a seal is first and last made. In this embodiment, as best seen in Fig. 1, the lip 27 of the intake manifold fairs into the cylindrical surface of the bore, whereas the lip 25 of the exhaust manifold defines a cylindrical extension of the bore. Because the portions of bores 36 and 38 defined by the housing are equal, the bore extension provided by the exhaust manifold extends the expansion and the ratio of compression to expansion is therefore less than one. In Fig. 5f, the rotors form, with the bore surfaces 37, 35, 39, a flow-through path for flow of air from intake 26 to exhaust 24. The flow of air through this path removes combustion products, and also cools the engine.

It is characteristic of the machine that the compression and expansion chambers just described, once formed, continuously change in volume, and the duration between final compression and initial expansion is only for an instant, (e.g. there is no extended transfer period or the like between the two) and thus work can be performed in an efficient manner. Referring back to Fig. 5, a similar cycle of compression, ignition and expansion takes place in the lower chamber 60', occurring exactly 180° out of phase with the upper chamber, with expansion of the ignited mixture acting on the trailing transition surface, T_£, of rotor 52 to transmit power through shaft 48 to power shaft 20 through gears 66, 64. Where the engine block 10 is made up of six such rotor pairs, as shown in Fig. 3, each of the rotor pairs is 120° out of phase with adjacent rotors in order to form a dynamically balanced engine. Segment 16 (Fig. 4) also includes an additional idler gear 74, to allow application of static torque to prevent backlash of the gears for better synchronization of the rotors. Also, use of idler gears distributes the power load for better efficiency.

Referring to Fig. la, in bore 38, the bore cylindrical surfaces 27, 39 and 25, 37 are defined in part by variable members 1002 which are movable toward or away from rotors 50, 52 in a manner to vary- the rotational angle at which the sealed relationship between apex seals 82 of rotors 50, 52 and the bore surfaces 27 begin and define the maximum confined initial volume of the chamber. This in turn provides the engine with a variable compression ratio, i.e. the ratio between the volume of the combustion chamber when it is first formed (Fig. 5a) and the volume of the chamber at the time of ignition, typically approximately at the point of minimum chamber volume (Fig. 5c).

In Fig. la, the members 1002 are in the maximum chamber position, with arcuate surfaces 1004 disposed for initial sealing contact with seals 82 at the earliest point, e.g. as also shown in Fig. 1. Downstream ends 1006 of variable members 1002 provide smooth transition onto fixed bore surfaces 1008, with surfaces 1010 contacting the curved surfaces 1012 of the fixed portions. At the upstream ends 1014 of variable members 1002, flexible fairing members 1016 also provide smoothly curved surfaces. Variable member 1002 is constructed to pivot about axis V located to the right of a line between the rotor axis and the end of movable surface 1004 closest to the pivot axis V. Member 1002 is selectively positioned by means of piston 1018 on the basis of engine operating conditions. Typically, the controlling condition is engine speed, with arcuate surfaces 1004 displaced to avoid early sealing contact at slower speeds, but other factors may be considered. If desired, the controlling factors can be evaluated by computer, shown in dashed line, which in turn controls the positions of surfaces 1004.

Referring to Figs, lb and lc, during operation at low power needs, arcuate surfaces 1004 are disposed at positions for delayed sealing contact, (Fig. lb) . In typical engine, an example of the compression ratio would be 3:1:10.35 (initial confined volume: minimum confined volume: final confined volume) and the peak pressure before ignition would be about 430 psia. The engine would be very efficient during periods of low power need due to the enormous expansion ratio, and would be very quiet due to mild combustion shock and low pressure exhaust. The exhaust pressure would be about two atmospheres versus 5 1/2 atmospheres in typical piston engines. In Fig. lc, the arcuate surfaces 1004 are disposed for early sealing contact and maximum compression rates for operation at higher engine speeds. In a typical engine, an example of compression ratio would be 9:1:10.35, with maximum pressure about 1437 psia, for driving and accelerating power. In Fig. 2a, a different sectional view of the rotary engine operating at low speeds is shown with variable member 1002 in retracted position, and in Fig. 3a, a chamber engine block with variable compression is shown.

In Fig. Id, another construction with the bore cylindrical surfaces 27, 39 and 25, 37 defined by variable members 1002 is shown. Hydraulic pressure is applied to surface 1014 of piston 1016 to urge it against the surface of asymmetrical cam 1018 in aperture 1020. The rotational position of cam 1018 controls the adjustment of surface defining bore 36, 38. Typically the contact surface 1004 is a soft material, e.g. ^• nickel, aluminum or plastic, to allow it to wear to fit. Movement of the contact surface is linear, with no provision for smooth transition between downstream surfaces. During high compresion engine operation, e.g. above 3,000 r.p.m., the clearance between adjacent surfaces would be lowered to less than 0.001 inches (0.025 mm). It is anticipated an automobile engine equipped with this system would require, tuning only every 60,000 miles (96,500 km).

Referring now to Fig. 6, a single rotor 50, identical to the rotors described above, is shown in detail with spline teeth and face seal labyrinths omitted. It comprises rotor body 80 to which are attached apex seals 82 and face seals 84, 86. At the apex of the rotating surfaces of rotor 50, i.e. at the intersection of the major cylindrical surface, C_τι_, and the transition surface, T, a special apex seal 82 is located in rotor aperture 88. Apex seal 82 is a oveable sealing member having sealing surface 90 (Fig. 8) adapted to contact the opposed surface 92 of the opposite rotor 52 and apply an outward sealing pressure against that surface. The sealing pressure applied by surface 90 decreases in magnitude with the^' increase in rotational velocity of rotor 50. Apex seal 82 has a moveable tail portion 94 that is free to slightly swing between a first position P, (Fig. 9) and a second position P₂ (shown in dashed line) about a pivot region positioned inwardly from the periphery of the rotor.

Referring to Fig. 7, each apex seal 82 consists of upper and lower sealing members 81, 83 urged axially apart by corrugated spring 96 which urges face surfaces 98, 100 of members 81, 83 into sealing contact with the opposed end surfaces 40, 40' (not shown here) of bore 36. Leakage through the spring compartment is restricted by an overlap of the joint between members

81, 83 at the exposed axial surfaces 90, 91 (Figs. 7 and 7a, and shown in dashed lines in the axial direction Fig. 8) .

In the preferred embodiment, the apex seal member 82 has an enlarged head portion 102 to which the tail portion 94 is joined.

Head 102 is fixed against radial movement but is allowed to rotate about axis X. Aperture 88 of rotor 50 is sized with some slight clearance (C, Fig. 9, e.g. .007 inch) to allow the tail portion 94 of seal 82 to rotate slightly about the axis X between a first (rest) position P, , and a second (high speed) position P₂- In the rest position, the tail portion 94 is biased toward position P, by spring 108 (Figs. 7a and 8) disposed in the rotor 50. As shown in Fig. 7a, spring 108 is a mildly corrugated thin piece of metal.

Axis X of head 102 lies on a radius R of rotor 50 (Figs. 9, 10) which is offset from the center of mass of the sealing member, either considering the entire mass of the member or the mass of the non-balanced tail portion 94. In Figs . 9 and 10 radius R cm __ is shown p - roj jected throug sh the center of mass cm, of the non-balanced portion. At rest, or at slow speeds, spring 108 biases the tail portion 94 of seal 82 toward positon P, , Fig. 9, where sealing surface 90 exerts maximum contacting pressure on the opposing surface 92 (transition surface T) . As rotor speed increases, centrifugal force, F-, Fig. 9a, effectively acts at the center of mass cm. As shown, the centrifugal force has a radial component, F-_ , which has no effect on seal position, and a tangential component, F _τ, which tends to move the center of mass, C.,, of the seal to overcome the opposed spring force, F_g, thus moving the sealing surface 90 toward position P₂ (a movement shown exaggerated in Fig. 9) . This movement reduces the contacting force F_cp exerted by the sealing surface 90 on the opposed surface 92 as speed increases. i operation at slow speeds, where the compression/expansion cycle of the machine takes a relatively long period of time, it is necessary that the seal between the apex of one rotor and the transition surface of the opposed rotor be tightly maintained, e.g. to avoid leakage and lost power. The spring 108 enables the apex sealing surface 90 to exert the required contact force F_ against the opposed transition surface 92. As rotational speed increases, the time duration of the cycle decreases, there is less time for leakage to occur, hence seal contact pressure becomes less critical. The novel seal relaxes this seal pressure and thus reduces efficiency loss that otherwise would occur due to friction. Further, the seal pressure may be made to vary with inverse relationship to the size of the chamber. In the preferred embodiment, because the seal member is biased mainly in the tangential direction relative to its rotor, the effective lever arm L of the contact force F_Cp is greatest in the rotor position of Fig. 5c where the chamber volume is smallest. Contrarwise, when the chamber is largest, i.e. when the seal member approaches alignment with the line of centers, between Figs. 5d and 5e, this lever arm is minimal. The total sealing pressure is also affected by friction effects that are taken into account in the design, bearing in mind that though the friction force tending to drag the seal open is also lowest in the position between Figs. 5d and 5e, the effective lever arm for this force is at a maximum, and vice versa with respect to the position of Fig. 5c.

Referring to Fig. 8a, apex seal 82 is shown positioned in rotor 50 which in this case has an enlarged aperture 88' for head 102. Also disposed in aperture 88' is restraint or damping means 1102 which has an arcuate surface 1104 complementary to the surface 1106 of seal head 102. A biasing means (not shown) urges the arcuate surface 1104 of restraint means 1102 into friction-brake contact.

At low rotational speed, the force of surface 1104 against seal 82 is not sufficient to prevent the centrifugal force generated by rotation of rotor 50 from overcoming the force of spring 108 to retract the sealing surface 90 for reduced sealing contact on opposed surface 92. As the rotational speed increases, the braking force of arcuate surface 1104, caused by centrifugal force acting on the mass of restraint means 1102 urging it outward, on the surface 1106 of apex seal

OMPI

^ τx 102, retards, and at sufficiently high speeds eliminates, rotation of the seal in aperture 88* holding sealing surface 90 in the retracted position between sealing contacts in the make-and-break contact cycle to maintain proper alignment for the next contact to thereby reduce initial contact pressure and also prevent introduction of vibration.

Referring now to Figs. 10, 11 and 12, the face surfaces 116, 116' of rotor 50 are sealed against the opposed end surfaces 40, 40' of the bore by means of flat plate seals 84, 86, as well as surfaces 98, 100 of apex seals 82 discussed above. Referring to Fig. 11, seal 84, and similarly seal 86, is comprised of two substantially flat, plate-form members 118, 120 at each surface, the outer surface of member 118 forming the contacting surface 122 between the rotor and the bore wall 40, 40'. The inner surface 124 of member 118 and the outer surface 126 of member 120, and inner surface 128 of member 120 and surface 130 of the rotor body 80 form additional contacting surfaces. By using two members 118, 120, the clearance between rotor surface 116 and bore surface 40 is divided into segments which are, of course, smaller than the total clearance and thus are more restrictive, due, e.g. to viscous friction, to gas flow between the opposing surfaces.

The surfaces of member 118 and member 120 also contain grooves 132 running substantially parallel to the cylindrical surfaces of the rotor. These grooves are divided from each other by ridges 134 of reduced clearance with the opposed surface, thus forming chambers or recesses for cascading pressure from the region of high pressure to the region of lower pressure (sometimes referred to labyrinth seals) . The chambers between member 118 and the bore surface 40, 40', between members 118, 120, and between member 120 and the rotor surface 130 are also connected by means of axial holes 136, 138 which enable a balancing of pressure between the individual parts. This balancing of pressure between the axially oriented chambers in effect serves to force members 118 and 120 apart to balance the clearance gaps between the individual surfaces whereby the leak through each path is substantially equal and the overall leakage in this region is reduced from what would occur if a single gap were employed. Fig. 12 is similar to Fig. 11 showing the members 118, 120 of the flat plate seals at a different position about the rotor axis. Pin 140 holds the seals 84, 86 to the rotor body 80. Referring to Fig. 10a, bias means 1202 for retractably biasing face seal 84' toward a complementary bore surface is shown. Referring also to Figs. 11a and 12a, bias means 1202 is a relatively flat sheet of corrugated spring steel fixed at point Q to retaining pin 140' which in turn is fixed in the rotor body 80'. Face seal 84', through which retaining pin 140' passes, rests on the opposed ends 1204, 1206 of bias means 1202 which at rest urge the seal 84' into sealing contact with the complementary bore surface (not shown) . Sealing contact is achieved along surfaces 122' while most of the intervening portion of the seal is apertured (1208) to prevent pressure differential between the face seal surfaces.

Referring to the force diagram in Fig. 10b, bias means 1202, which has dimensional extent both along the rotor radius, R_R, and also perpendicular thereto P_R, is fixed to the rotor at point Q along the length of the bias means closer to the inner end from its center of mass. As the rotational speed of the rotor increases, centrifugal force, _CM, acts on the perpendicular dimensional component of the spring outward of the point of attachment to overcome spring force Fg, and reduce the perpendicular component. (The portion of the spring lying inwardly at the point of attachment is also urged outward by the centrifugal force generated.)

As the perpendicular dimensional component of the spring is reduced, the biasing force of the spring against the face seal is also reduced as is the contacting force of the sealing surfaces against bore wall. Thus, frictional contact is reduced at higher engine speeds when, due to the shortened cycle time, reduced sealing is required. In another embodiment (Fig. lib) , two bias means 1202', 1202*' may be used to bias two overlying face seals 118', 120' to divide the clearance for reduced leakage, as discussed above relative to Fig. 11. Referring to Figs. 20, 21 and 22, a face seal 1302 without a flush radial surface is shown. Arcuate face seal 1302 lies within an arcuate aperture 1304 disposed inward from the radial surface 1306 of rotor 1308. Over its major length, seal 1302 fits into aperture 1304 with tight clearance to provide a tortuous path for gas leakage around the seal. At spaced points along the aperture, retaining pins 1310 are provided with attached bias means 1312 that apply biasing force to seal 1302 toward the complementary bore surface 1314. As discussed above, centrifugal force generated by increased rotor rotational speed cause bias means 1312 to apply reduced force to the seal.

Referring back to Fig. Id, and also to Figs. 12b, c, d and e, a track sealing system for retarding leakage from fluid chamber 60 is shown. Defined in the

OMPI ^NATlO surface 25 of bore 36 are a series of parallel grooves 1022 lying generally coaxial with the bore, and perpendicular to the direction of rotation of rotor 50. The size, shape and arrangement of the grooves varies with application. In a typical compression engine (shown) the grooves are about 0.125 inches (3.2 mm) deep, and have approximately the same width, W. The distance between grooves Y, is about equal to W, or slightly less. The relationship of the close-mated surfaces of the moving rotor and the fixed bore surface defining the grooves are shown in enlarged scale in Figs. 12b and 12d, to which we now refer.

In the preferred compression engine, chamber 60 is at a pressure, P relatively higher than port 24. Fluid under pressure in chamber 60 leaks through the gap 1024, typically between about .004 to .007 inches (0.10 to 0.18 mm) , between the moving surface of rotor 50 and the fixed bore surface 25 in the direction indicated by arrow . Leakage beyond the first groove is somewhat limited as the leaking fluid fills and pressurizes the relatively large volume, compared to the narrow gap, of the groove to a pressure, P, , approaching, but slightly below the chamber pressure P . Pressurization of the grooves occurs progressively as shown by the bar graph of pressure in Fig. 12c. If the opposed bore and rotor surfaces were fixed relative to each other, the pressure in the gap and grooves would stabilize quickly at a pressure close to that of the chamber, P . However, movement of rotor 50, see Fig. 12d in which the chamber has enlarged due to rotor movement and the pressure has correspondingly decreased to P ' , causes each groove progressively to be reexposed to the chamber. As shown in Fig. 12d, pressure P, in the first groove, now exposed, equals the chamber pressure, Pc' In this manner, the cascade of grooves is reexposed more quickly than the pressure of- leaking fluid can advance along the gap between the opposed surfaces, and lost mass is recovered to the system. Fig. 13 shows an alternate embodiment of the engine of Fig. 1, with three rotors 150, 152, 152' rotating in phase in the same direction. By use of an additional rotor 152', a second chamber 160a, 160a' (only chamber 160a' in the lower phase is shown) is formed simultaneously in each stage of rotation, i.e. in Fig. 13 the engine is forming two compression chambers 160' and 160a'. At the same time, a flow-through path from intake 126 to exhaust 124 is formed across the top of the rotors again as in Fig. 1. An engine of this embodiment would typically provide greater power output for the weight of engine machinery required, as compared to the embodiment of Fig. 1.

Fig. 14 shows a fluid pressure pump 210. In the upper phase (shown) , fluid taken into the engine through intake 226 is pressurized in chamber 260 by action of rotors 250, 252. Valving means 228 remains closed until the desired degree of compression of the fluid in chamber 260 is achieved, e.g. if the fluid is substantially noncompressible, e.g. water, valving means 228 will open almost immediately and the compressive action of the device will be used to squeeze the liquid forcefully through exit port 224. If the fluid is compressible, valving means 228 will remain closed until the fluid is substantially compressed, e.g. until rotor 250 and rotor 252 reach a point close to maximum compression. Compression in chamber 260 is achieved by the combined action of the rotors 250 and 252 with the cooperative surfaces of engine 210 to reduce the size of chamber 260 to its minimum point. A similar process would occur in the lower phase, i.e. 180° out of phase with the process just described, with the valving means 228* acting to allow compressed fluid in chamber 260' to exit. Referring to Fig. 15, a device 310 similar to the fluid pressure pump of Fig. 14 is shown. However, in this embodiment the rotors 350, 352 rotate in a counter clockwise direction thus causing chamber 360 to expand in size. As chamber 360 is enlarged by rotation of the two rotors, valving means 328 activates to allow fluid to be drawn through intake 326 into chamber 360. The rotation of rotor 350 creates a lowered pressure in chamber 360 which upon opening of the valving means induces fluid to enter chamber 360. Again a similar process would take place 180° out of phase in lower chamber 360' .

Referring to Figs. 16-16c, a pump 410 with simultaneous suction and pumping phases suitable for pumping fluid, e.g. for use as a circulation pump, is shown. The pump comprises rotors 450, 452, slightly different in configuration from the rotors of Fig. 1 to accommodate a closer spacing of the rotor axes in this embodiment (closer spacing enabling increase of pumping flow versus size of overall machine) . The rotors rotate in phase in the same direction and at the same speed, and intake and exhaust ports 426, 426' and 424, 424', respectively, are provided, each with an associated one-way-valve 425. In Fig. 16, chamber 460, sealed by the surfaces of the rotors and the block, is decreasing in volume to force fluid out through one-way exhaust 425 and port 424 while the back volume draws fluid in primarily through intake port 426'. In Fig. 16a, both upper chambers 460 and 460a are at minimum volume. In Fig. 16b, chamber 460a is expanding in volume to draw fluid into the pump through one-way intake valve 425 and port 426 while fluid is exhausted from the back volume primarily through exhaust port 424*. In Fig. 16c, chamber 460a' is nearly sealed by the rotor surfaces for exhaust of fluid through valve 424'.

Fig. 17 shows an internal combustion engine 510 of operation similar to Fig. 1. However, in this embodiment rotors 550, 552 are of different size. Both rotors move in the same direction at the same revolutionary speed, i.e. same rpm, but have different surface speeds. Operation of this device is the same as the earlier embodiments.

The seals of this embodiment illustrate some of the variations that can be used to advantage. The seals 582 of the smaller rotor are of cantilever form, the larger root portion 502 being fixed to rotor 552, and the slender tail portions 504 being spring cantilever extensions integral with root 502, but free to deflect within a range of clearance provided by the slot in the rotor through which they extend. The ends of these extensions form seals as in the previously described embodiment, Figs. 7-9a.

The leading seal 584 of the larger rotor in Fig. 17 is an inertial seal, specially constructed to cause the seal surface to radially retract between rest and high speed positions. This seal member can form effective seals both with the rotor and bore surfaces at respective stages of rotation. This is accomplished by selected location of the seal surface and the center of the mass. The radius R ' is projected from the rotor center to the pivot axis X' for the seal member. The center of mass cm' of the seal member lies to one side of this radius while the sealing surface lies to the other side. Thus, as rotor speed increases and spring force F is progressively overcome, the center of mass cm* moves toward alignment with radius R _*__ (and toward the large cylindrical surface) while the sealing surface rotates away from that radius in the rotational direction opposite direction opposite to that of rotor 550, to a position closer to the center of the rotor 550 and away from the surfaces against which it seals. In this case both the frictional and effective intertial forces act in the same direction. The trailing seal 588 is similar to seal 584 positioned in a way to be effective with the bore 537 and the opposed rotor. It also rotates, with increase in speed, in direction opposite to that of the rotor, in this case away from the large cylindrical surface, toward the following transitional surface.

Fig. 18 shows still another embodiment of a device 610 according to the invention. In this embodiment, three rotors 650, 652, 652* rotate in the same direction but at different rpm, e.g. center rotor 650 turns at one half the revolutionary speed of rotors 652, 652'. Rotors 652, 652* are 180° out of phase, but operate at the same position on the cycle, i.e. simultaneously form compression and expansion chambers 660, 660a* with the surface of center rotor 650. Other Embodiments

Other embodiments of the invention are within the following claims. For example, various rotor shapes and multiple rotor configurations are anticipated within the invention, e.g. where the application dictates, the small cylindrical surface may not be configured for sealing contact with the opposed large cylindrical surface, or the apex seal may not trace the point of contact with the opposed transition surface. As shown in Fig. 17, the apex seal 582 may be -in the form of a

OMPI cantilevered member 504 with the head portion 502 fixed against rotation, also the head portion maybe fixed to the rotor surface, e.g. by a screw. The labyrinth effect employed for the seals on the rotor faces could also be employed on the cylindrical surfaces by means of axially alinged recesses 532 on the major cylindrical surfaces disposed for rotor-to-bore wall sealing relationship during critical periods of compression and/or expansion. The intake and/or exhaust ports could be aligned axially. Also, variable members may be used to define a portion of the bore wall on the expansion side of the machine, e.g. for an expansion machine, or may be used on both sides, e.g. to vary the timing and rotational angle of the cycle, or could be used in other types of rotary devices or engines. Referring to Fig. 19, a rectilinear head 102' may be used on apex seal 82' to fix the bias of the flexible tail 94' in the rest position, without requiring a contact spring. The damping or restraint means could be made adjustable by allowing variation of the position of the friction brake contact surface on the seal surface relative to the rotor radius, i.e. the clamping force generated is greater where the surface is perpendicular to the radius as opposed to some other angle approaching parallel. he clamping or restraint means could also be used in other types of rotary devices or engines, e.g. of the Wankel type, to temporarily fix or restrain a seal to reduce contact at higher speeds. The bias means sensitive to centrifugal force could be used to retract or project seals or other surfaces in other types of rotary devices or engines.

Claims

- 36 - 1. In a rotary machine that cyclically defines a fluid chamber of progressively changing volume, said machine including a stationary block, first and second adjacent cylindrical bores formed in said block about parallel axes, said bores being closed by end surfaces, the axes of said bores being spaced apart a distance less than the sum of the radii of the adjacent bores, first and second rotors disposed in the respective bores on fixed axes corresponding to the axes of the respective bores, said rotors having surfaces arranged to form a progressive rotor-to-rotor seal between the two rotors while each rotor also forms a rotor-to-bore-wall seal with the wall of its respective bore and end seals with respective end-closing surfaces of said bores, said rotor surfaces adapted to serve as chamber bounding surfaces which cooperate with relatively stationary surfaces of the machine to define said chamber of changing volume, said rotors being mounted for dependent rotation, intake means for introducing fluid into said chamber, and exhaust means for exhausting fluid from said chamber, the improvement wherein, in combination, the said rotors are arranged to rotate in the same rotary direction. 2 the chamber-bounding surface of said first 3 rotor is a cylindrical surface of radius substantially ⁴ equal to the radius of said first bore, and centered on 5 the axis thereof, 6 said cylindrical surface having a ⁷ substantial arcuate extent, arranged to maintain, ⁸ throughout a chamber-defining range of rotation, sealing ⁹ relationship with both the wall defining the respective 0 bore to form a rotor-to-bore-wall seal, and a surface of ⁱ the second rotor to form said rotor-to-rotor seal, 2 at least part of the chamber-bounding surface ³ of said second rotor having a progressively changing ⁴ radius to cause the volume of said chamber to progressively change during said range of rotation, ^δ said rotor surfaces being constructed to avoid ⁷ interfering contact during said dependent rotation in ⁸ said same rotary direction.

- 38 - 2. The rotary machine of claim 1 wherein said cylindrical surface of said first rotor ends at an apex portion adapted to form said rotor-to-rotor seal with the chamber-bounding surface of said second rotor, the chamber-bounding surface of said second rotor being a transition surface which extends from its minimum radius point at which said apex portion of said first rotor forms therewith said seal, through a curve of increasing radius to a point having a radius corresponding substantially to the radius of said second bore, said curve of said transition surface of said second rotor being shaped to correspond substantially to the path of said apex portion of said first rotor over the range in which said rotor-to-rotor seal is maintained, whereby as said rotors rotate in the same direction said apex portion moves in sealing relationship along said transition surface, and the volume of said chamber is progressively changed as a result of movement of said transition surface of said second rotor relative to the cylindrical surface of said first rotor.

3. The rotary machine of claim 2 wherein the direction of rotation of said rotors causes said transition surface to move relatively toward said cylindrical surface while said apex portion moves along said transition surface curve to points of increasing radius, to decrease the volume of said chamber. - 39 _ 4. The rotary machine of claim 3 wherein said intake means is defined by cooperative opposed surfaces of at least one of said rotors and said block, said surfaces, during rotation of said rotors prior to the formation of the respective rotor-to-bore-wall seal, provide a path for inflow of fluid for said chamber.

5. The rotary machine of claim 4 wherein said intake means is associated with a source of pressurized fluid which forces said fluid through the inflow path formed by said cooperative surfaces of said rotor and block.

6. The rotary machine of claim 5 wherein, simultaneously while said inflow path is defined by cooperative opposed surfaces of one of said rotors and said block, an outflow path is defined by cooperative opposed surfaces of the other said rotor and said block in a manner establishing a through-path for flow of fluid through the space in which said chamber is to be formed by continued simultaneous rotation of said rotors,

7. The rotary machine of claim 6 in which said chamber comprises a compression chamber of an internal combustion engine, said flow paths being adapted to enable flow-through of air for cooling working surfaces of said engine and providing combustion air. 8. The rotary machine of claim 7 in which a stationary surface bounding said chamber when the volume of said chamber is reduced includes fuel injection or ignition means.

9. The rotary machine of claim 3 in the form of a compressor or pump wherein said exhaust means comprises porting for outward flow of pressurized fluid from said chamber while said chamber decreases in volume.

- 41 - 10. The rotary machine of claim 3 having successive compression and expansion stages, wherein said transition surface of said second rotor is a leading transition surface which is followed by a second cylindrical surface of radius substantially equal to the radius of said second bore and centered on the axis thereof, a second apex formation between said second cylindrical surface and said transition surface adapted to form a second rotor-to-rotor seal with a trailing transition surface of said first rotor which follows said cylindrical surface thereof, said trailing transition surface of said first rotor extending from the cylindrical surface of said first rotor through a curve of decreasing radius to the minimum radius point at which said apex portion of said second rotor forms a seal therewith, said trailing curve of said transition surface of said first rotor being shaped to substantially correspond to the path of said apex portion of said second rotor over the extent of said second rotor-to-rotor seal, whereby as said rotors continue to rotate in the same direction after decreasing the volume of said chamber, said apex portion of said second rotor immediately moves into sealing relationship with and thence along said trailing transition surface of said first rotor, while said trailing transition surface moves apart from the cylindrical surface of said second rotor to increase the volume of said chamber, whereby expansion occurs immediately following compression.

-ftORE

OMPI _ - 42 - 11. The rotary machine of claim 10-in the form of an internal combustion engine, said chamber when bounded by said cylindrical surface of said first rotor and said transition surface of said second rotor comprising an air compression chamber, said engine including means to cause fuel ignition within said chamber when the volume of said chamber is reduced, and said chamber when bounded by said transition surface of said first rotor and the cylindrical surface of said second rotor comprising an expansion chamber in which said transition surface of said first rotor is adapted to transform the expansive force of combustion gas into shaft energy.

12. The rotary engine of claim 11 wherein said intake means is defined by cooperative opposed surfaces of at least one of said rotors and said block, said surfaces, during rotation of said rotors, prior to the formation of the respective rotor-to-bore-wall seal, providing a path for inflow of air.

13. The rotary engine of claim 12 wherein said intake means is associated with a source of pressurized air which forces said air through the inflow path formed by said cooperative surfaces of said rotor and block.

- 43 _ 14. The rotary engine of claim 13 wherein, simultaneously while said inflow path is defined by cooperative opposed surfaces of one of said rotors and said block, an outflow path is defined by cooperative opposed surfaces of the other said rotor and said block in a manner establishing a through-path for flow of air through the space in which said chamber is to be formed by continued simultaneous rotation of said rotors.

15. The rotary machine of any of claims 10, 11, 12, 13 or 14 wherein each of said rotors has a said transition surface that precedes the cylindrical surface of said rotor and a transition surface that follows said cylindrical surface, there being a said apex formation at the beginning and ending of the cylindrical surface of each rotor, different sets of said surfaces and apex formations, during different stages of rotation of said machine, forming successive combustion chambers.

16. The rotary machine of claim 15 wherein between the two transition surfaces of each rotor there is a minor cylindrical surface of radius substantially equal to the difference between the length of the line of centers of said rotors and the radius of the major cylindrical surface of the other rotor, said minor cylindrical surface arranged to be at the line of centers when the major cylindrical surface of the other rotor is at the line of centers, thereby to form a seal.

OMPI 17. The rotary machine of claim 15 wherein said rotors are of identical size and shape and adapted to rotate at the same speed to form a pair of spaced apart combustion chambers.

18. The rotary machine of claim 2 wherein the direction of rotation of said rotors is adapted to cause said apex portion to move along said curve of said transition surface to points of decreasing radius, to increase the volume of said chamber.

19. The rotary machine of claim 18 in the form of a pump wherein said intake means comprises inlet porting to enable flow of fluid into said chamber while said chamber expands.

20. The rotary machine of claim 18 in which said chamber comprises an expansion chamber for a power-generator, said transition surface of said second rotor being adapted to transmit the expansive force of the contained gas into shaft energy.

21. The rotary machine of claim 20 in which, during rotation of said rotors after expansion of said gas, said exhaust means is defined by cooperative opposed surfaces of at least one of said rotors and said block, defining an outflow path for said gas.

- 45 - 22. The rotary machine of claim 21 in the form of an internal combustion engine wherein, simultaneously while said outflow path is defined by cooperative opposed surfaces of one of said rotors and said block, an air inflow path is defined by cooperative opposed > surfaces of the other said rotor and said block in a

⁷ manner establishing a through-path for flow of air

⁸ through the space occupied by combustion gas, said

⁹ inflow path being associated with a source of 0 pressurized air to purge said space of combustion gas.

1 23. The rotary machine of any of the claims

² 2-9 or 18-22 wherein, beyond the small radius end of the

³ transition surface, said second rotor has a minor

⁴ cylindrical surface of radius substantially equal to the

5 difference between the length of the line of centers of ^δ said rotors and the radius of said cylindrical surface

7 of said first rotor, said minor cylindrical surface 8 arranged to be at the line of centers when the ⁹ cylindrical surface of the first rotor is at the line of ° centers, thereby to form a seal, enabling said chamber 1 to be formed for an extended duration of the rotation of 2 the rotors and with a large ratio between smallest and 3 largest volume of said chamber.

1 24. The rotary machine of claim 2 wherein each

² of said rotors has a said cylindrical surface, a said

³ apex portion and a said transition surface, to provide,

⁴ at different points during rotation, chambers in

⁵ accordance with the relationship of claim 2. - 46 - 25. The rotary machine of claim 24 wherein each of said rotors has a transition surface which precedes its cylindrical surface, said machine adapted to provide two compression chambers located at different positions.

26. The rotary machine of claim 24 wherein each of said rotors has a transition surface which follows its cylindrical surface, said machine adapted to provide two expansion chambers located at different positions.

27. In a rotary machine, which comprises a rotor and means defining a bore surface with which said rotor is arranged to interact to cylically define a fluid chamber during rotation of said rotor, the improvement wherein a variable member defining a portion of said bore surface is movable toward and away from said rotor in the manner to vary the rotational position of a transition point at which a sealed relationship between said rotor and said bore surface begins or ends, and means responsive to desired operating conditions to vary the position of said variable portion thereby to vary the rotational position of said point at which said sealed relationship begins or ends.

28. The rotary machine of claim 1 in the form of a rotary internal combustion engine in which said rotor and bore surface are cooperatively constructed to form at least part of a combustion chamber, said variable member defining with said rotor the point where the volume of said combustion chamber is first closed, variation in the position of said member serving to vary the compression ratio of said engine.

29. The rotary machine of claim 27 or 28 wherein said bore surface is comprised in part of a relatively stationary first bore surface segment of radius which progressively enlarges relative to the radius of said rotor at points at progressively greater arcuate distance about the rotor axis from the point of said segment which lies closest to said rotor, said variable member defining a second bore surface segment which is movable outwardly relative to said first segment and has a transition end portion disposed closely adjacent to said relatively stationary segment, said transition end portion being movable along said first bore surface segment as said variable member moves outwardly from said rotor axis to expose an increasing amount of said first bore surface segment.

30. The rotary machine of claim 29 wherein said variable member is pivotable about a pivot axis lying directly outwardly from said first bore surface segment, and said first bore surface segment is cylindrical, centered on said pivot axis.

31. The rotary machine of claim 30 wherein the second bore surface segment defined by said variable member is an arcuate surface of radius substantially equal to the radius of said rotor, and said machine further includes a flexible fairing member disposed at the outward end of said variable member, and a positioning means adapted to selectively position said variable means. 32. A rotary machine having compression and expansion stages comprising: a block, at least two cylindrical bores formed in said block about parallel axes and closed at their ends, intake means for introducing fluid into said bores, exhaust means for exhausting fluid from said bores, and rotors coaxially disposed in each said bore, and arranged to rotate in the same direction, each said rotor having, at spaced apart locations about its axis, successive major and minor cylindrical surfaces concentric with the axis of said rotor and transition surfaces between said cylindrical surfaces so that there is a leading transition surface preceding each major cylindrical surface and a trailing transition surface following each major cylindrical surface, the intersections of said leading and trailing transition surfaces with their respective major cylindrical surfaces forming respective leading and trailing apex portions, the major cylindrical surface of each said rotor having a radius substantially equal to the inside radius of the respective bore, the axes of adjacent bores being spaced at a distance less than the sum of the radii of said adjacent bores whereby the projected path of the rotor in each bore intersects the projected path of the rotor in the adjacent bore,

OMPI the minor cylindrical surface of each said rotor having a radius substantially equal to the length of the line of the centers between said axes of said adjacent rotors less the radius of the major cylindrical surface of the adjacent rotor. the rotors being constructed and arranged so that the passage of the major cylindrical surface of each rotor past said line of centers coincides with the passage past said line of centers of the minor cylindrical surface of the adjacent rotor, the rotors also being constructed and arranged so that the passage of each leading and trailing transition surface of each rotor coincides with the passage of the trailing and leading apex portion respectively of the adjacent rotor, each said transition surface being shaped to maintain a sealing relationship with the coincident apex portion of the adjacent rotor, whereby the surfaces of said adjacent rotors remain in close proximity during the working phase of said rotors, and the surfaces of adjacent rotors together with the surfaces of the corresponding bores are cooperatively adapted to progressively form chambers that successively reduce and enlarge in volume.

^■i E

OMPI ?^^?τt 1 33. The rotary machine of any of the claims 2,

218, 24^r 32 wherein said apex portion includes a

3 movable sealing member adapted to contact the opposed

4 transition surface during the volume-changing action of

5 the rotors, said sealing member adapted to apply outward

6 sealing pressure that decreases in magnitude with

7 increase in the velocity of rotation.

1 34. The rotary machine of claim 33 wherein

²when said rotors are at rest, said sealing member is

3 disposed in a first position in the respective rotor,

⁴ bearing with pressure against said transition surface of

⁵ the opposite rotor, the rotor contacting surface of said sealing member being free to shift toward a second

⁷position in a movement which progressively relieves its

⁸pressure against said transition surface, said sealing

⁹member being constructed and arranged to move toward 1°said second position in response to increased speed of 11rotation of said rotor thereby to relieve said sealing l²pressure as speed of said rotor increases.

_ 52 _ 35. In a rotary device that includes a movable sealing member adapted to form a seal with an opposed surface during rotation of said rotor, the improvement wherein said sealing member is disposed in a first position in the rotor to bear with pressure against said opposed surface, the contacting surface of said sealing member being free to shift toward a second position in a movement which progressively relieves its pressure against said opposed surface, said sealing member being constructed and arranged in response to increased speed of rotation of said rotor to move toward said second position therby to relieve said sealing pressure as speed of said rotor increases.

36. The rotary machine of claim34 or 35 wherein said sealing member has a mass distribution relative to its mounting to cause said sealing member to move to relieve said sealing pressure as a result of intertial effects as said speed increases.

37. The rotary machine of claim 36 wherein the effective movable portion of said sealing member is free to slightly swing between said first and second positions about a pivot region positioned inwardly from the periphery of said rotor, said pivot region being offset from a radius of said rotor that projects to the center of mass of said movable portion.

6. The rotary machine of claim 7 wherein said center of mass and said sealing surface lie to the same side of said pivot region. 39. The rotary machine of claim 37 wherein said effective portion of said sealing member comprises a cantilever spring portion capable of flexing generally in said pivot region in response to said centrifugal effects.

40. The rotary machine of claim 37 wherein said effective portion of said sealing member comprises a rigid element extending outwardly from a rotary pivot bearing.

41. The rotary machine of claim 36 wherein an independent spring means biases said"sealing member toward said first position in a manner that the force of said spring means can be progressively overcome by centrifugal effects as said rotor increases in speed.

42. The rotary machine of claim 36 wherein said second position of said sealing surface is disposed toward a large diameter surface of its rotor, relative to said first position.

43. The rotary machine of claim 33 wherein said sealing member, at a given speed of rotation of said rotor, is constructed and arranged to bear against said transition surface with pressure normal to said transition surface which varies generally inversely with change of volume of said chamber. 44. The rotary machine of claim 27, said machine further including a stationary block, first and second adjacent substantially cylindrical bores formed in said block about parallel axes said bores being closed by end surfaces, the axes of said bores being spaced apart a distance less than the sum of the radii of the adjacent bores, first and second rotors disposed in the respective bores on fixed axes corresponding to the axes of the respective bores, said rotors having surfaces arranged to form a progressive rotor-to-rotor seal between the two rotors while each rotor also forms a rotor-to-bore-wall seal with the wall of its respective bore and end seals with respective end-closing surfaces of said bores, said rotor surfaces adapted to serve as chambe -bounding surfaces which cooperate with relatively stationary surfaces of the machine to define said chamber, said rotors being mounted for dependent rotation, intake means for introducing fluid into said chamber, and exhaust means for exhausting fluid from said chamber, the further improvement wherein, in combination, the said rotors are arranged to rotate in the same rotary direction, the chamber-bounding surface of said first rotor is a cylindrical surface of radius substantially equal to the radius of said first bore, and centered on the axis thereof, said cylindrical surface having a substantial arcuate extent, arranged to maintain, throughout a chamber-defining range of rotation, sealing relationship with both the wall defining the respective bore to form a rotor-to-bore-wall seal, and a surface of the second rotor to form said rotor-to-rotor seal, at least part of the chamber-bounding surface of said second rotor having a progressively changing radius to cause the volume of said chamber to progressively change during said range of rotation, said rotor surfaces being constructed to avoid interfering contact during said dependent rotation in said same rotary direction.

45. In a rotary machine which comprises a rotor, means defining a complementary opposed surface, and a sealing member bodily carried by said rotor member and movable with respect to said rotor member toward said complementary surface to form a seal with said surface, the point of sealing of said sealing member progressing about said surface as said rotor rotates, the improvement comprising restraint means responsive to increase in the rotational speed of said rotor to apply increased restraint on the freedom of relative motion of said sealing member toward said surface thereby to enable decrease or elimination of direct pressure contact between said sealing member and said surface upon increased speed of said rotor. 46. The rotary machine of claim 45 wherein said restraint means comprises a restraint member carried by said rotor and defining a friction brake surface engageable with said sealing member in a manner to restrain said movement of said sealing member, said restraint member being responsive to increase in centrifugal force attributable to increased speed of rotation of said rotor, to increase the pressure of engagement of said friction brake surface upon said sealing member, thereby to increase the restraint of said sealing member.

47. The rotary machine of claim 46 wherein said seal member comrises a member having a rotary bearing surface bearing upon a corresponding surface defined by said rotor, and a sealing member extending from and rotatable with said rotary bearing surface to move into sealing engagement with said complementary surface, said restraint member comprising a member lying inwardly of said sealing member, said restraint member having a surface engaged for relative motion with a corresponding surface of said sealing member, said restraint member being constrained against rotation with said sealing member and disposed to respond to increase in centrifugal force to engage said sealing member with increased pressure, thereby to frictionally restrain rotation of said sealing member toward said complementary surface. 48. In a rotary machine, which comprises a rotor and * means defining relatively stationary surfaces with which said rotor is arranged to interact to cyclically define a fluid chamber during rotation of said rotor, the improvement wherein said rotor includes a seal means for providing a sealing relationship with a complementary stationary surface of said chamber during rotary motion of said rotor, said seal means comprised of at least one sealing member carried on said rotor and defining a sealing surface disposed in face-to-face relationship with said complementary surface, bias means between said member and said rotor adapted to bias said sealing member toward said complementary surface, said bias means having a biasing portion with at least a component lying perpendicular to the radius of said rotor and a point of attachment spaced from said biasing portion, said biasing portion adapted and configured to apply a biasing force to said seal toward said complementary surface, the dimensional extent of said biasing portion in a direction perpendicular to the radius of said rotor at a first speed of rotation being different from said dimensional extent at a second speed of rotation, said biasing portion adapted to move elastically between positions at said first and second speeds of rotation in response to increase of centrifugal force thereon, the biasing force applied by said biasing portion to said seal varying with variation in said dimensional extent. 49. The rotary machine of claim 48 wherein said bias means is a corrugated relatively flat, resilient member attached to said rotor at a point along the length of said bias means inward of the center of mass of said bias means, the outer end of said bias means having a dimensional component perpendicular to a radius of said rotor, whereby, due to said perpendicular dimensional component, the bias means, when said rotor is at rest, biases a sealing member toward a complementary stationary surface, and when said rotor is rotating at a different, higher speed, the outer end of said bias means is urged radially outward by centrifugal force thereby reducing its perpendicular dimensional component and reducing the biasing force of said bias means toward said sealing member.

50. The rotary machine of claim 48 wherein said sealing member comprises a plurality of flat sealing members disposed in axially superposed relationship, there being bias means between each pair of said flat sealing members and between said rotor and its adjacent said flat sealing member, adapted to bias the respective members apart, whereby the total clearance is divided between a plurality of small, flow-resistant gaps.

- 59 -

1 51. The rotary machine of claim 1

² wherein at least one of said rotors includes an

³ end seal means for providing a sealing relationship with

⁴ an end surface of said bore during rotary motion of said

⁵ rotor,

⁶ said seal means comprised of at least one

⁷ generally flat sealing member carried on said rotor and

⁸ defining a sealing surface disposed in face-to-face relationship with said end surface, ° bias means between said member and said rotor 1 adapted to bias said sealing member toward said end 2 surface, and 3 said sealing surface including at least one ⁴ recess whereby fluid leakage between said end surface 5 and said sealing surface from a region of high pressure to a region of lower pressure encounters an enlarged ⁷ volume defined by said recess having pressure of ⁸ intermediate magnitude, ⁹ said end and sealing surfaces adapted to ° isolate said recess to maintain the pressure therein at 1 said intermediate magnitude.

52. In a rotary machine including a rotor adapted to form a seal with an opposed end surface of a bore in which said rotor resides, said rotor including an end seal means for providing a sealing relationship with said end surface uring rotary motion of said rotor, said seal means comprised of at least one generally flat sealing member carried on said rotor and isposed in face-to-face relationship with said end surface, means disposed at least between said member and said rotor adapted to bias said sealing member toward said end surface, said sealing surface including at least one recess whereby fluid leakage between said end surface and said sealing surface from a region of high pressure to a region of lower pressure encounters an enlarged volume defined by said recess having pressure of intermediate magnitude, said end and sealing surfaces adapted to isolate said recess to maintain the pressure therein at said intermediate magnitude.

53. The rotary machine of claim 51 or 52 wherein said bias means comprises means for applying fluid under pressure to the undersurface of said sealing member.

54. The rotary machine of claim 3 wherein the said fluid under pressure comprises leakage from the high pressure region of said machine.

- UR

OMP τ 55. The rotary machine of claim 54 wherein at -least one leakage-receiving recess is disposed below

³ said flat seal member, fluid under pressure in said

⁴ recess adapted to bias said overlying flat seal member toward a sealing relationship with said end surface.

1 56. The rotary machine of claim 51 or 52 wherein said sealing surface includes a plurality of spaced apart recesses, said recesses arranged to be encountered successively by the leakage fluid, the pressure in said recesses being of progressively decreasing magnitude from the region of high pressure to the region of lower pressure along the leakage path.

57 • The rotary machine of claim 51 or 52 wherein said seal means comprises a plurality of flat seal members disposed in axially superposed relationship, there being bias means between each pair of said flat seal members and between said rotor and its adjacent said flat seal member, adapted to bias the respective members apart, whereby the total clearance is divided between a plurality of small, flow-resistant gaps.

58. The rotary machine of claim 57 wherein at least one recess is formed between each pair of said flat seal members and between said rotor and its adjacent flat seal member, and means to provide fluid under pressure in said recesses to serve as said bias means on the respective flat seal members. - 62 - 59. The rotary machine of claim 58 wherein a recess defined on one sealing surface of said seal member is connected by generally axially disposed equilibrating openings defined in said flat seal member to a recess defined at the opposite surface of said seal member, whereby the pressure in said axially disposed recesses can be substantially balanced.

6⁰. The rotary machine of claim 10 or 11 wherein the ratio of the maximum to minimum compression chamber volume is smaller than the ratio of maximum to minimum expansion chamber volume.

61. In a machine which comprises a moving element and means defining a fixed surface with which said moving element is arranged to interact to cyclically define a fluid chamber during movement of said element, a surface of said element and said fixed surface adapted to be disposed in close-mated relationship to retard movement of fluid therebetween between ^"said fluid chamber and an area of different pressure, the improvement wherein a multiplicity of grooves defined in said fixed surface are configured and arranged to permit fluid moving between said surfaces in close-mated relationship from a first area of relatively high pressure to a second area of relatively lower pressure to pressurize said grooves in progression from said first area toward said second area, and said grooves defined in said fixed surface are configured and arranged to provide that movement of said surface of said element in close-mated relationship with said fixed surface is adapted to progressively expose said grooves to said fluid chamber, whereby as leakage of said fluid between said close-mated surfaces from the area of relatively higher pressure into a first said groove defined in said fixed surface adjacent to the area of relatively higher pressure increase the pressure therein, movement of said element causes said first groove to be exposed to said area of higher pressure, thereby increasing the sealing performance of said close-mated surfaces. 62. The machine of claim 61 the form of a rotary machine, wherein said moving element is a rotor and said fixed surface is a bore surface, said rotor and bore surface being arranged to interact to cyclically define a fluid chamber during rotation of said rotor.

63. The machine of claim 61 wherein the gap between the close-mated surface of said moving element and said fixed surface is of the order of between about .004 to .007 inches (.010 to 0.18 mm).