US2381823A - Liquid sealed pump - Google Patents

Description

y Aug. 7, 1945.I

HQ E. LA BOUR LIQUID SEALED PUMP Filed April 17, i942 :s sheets-sheet 1y Aug; 7, 1945. H. E. LABOUR LIQUIb SEALED PUMP Filed Apri; 1v, 1942 :s sheets-sheet 2 INVENTOR Taffy Lal-Bbw# BY f" z:-

vPatented ug. 7, 1945l 22 Claims.

My invention relates to centrifugal pumps and more particularly to self-priming pumps.

The chief object of the invention is to provide an improved method of and means for liquid sealing the shaft of a pump. y

Another object of the invention is to provide vmeans for insuring segregation of the bearings c from the sealing liquid. A further object is to provide a seal against the escape-of fumes or vapor from the pump.

A further object is to provide an improved mounting for the pump. A further object of the invention is to provide a. design having parv ticular advantages for production in acid resisting materials.

A further object is toprovide an improved restriction against too rapid backow.

A further object is to provide a. self-priming centrifugal pump of-al design which may advantageously employ a liquid seal of my invention and embody other and incidental improvements.

c Other objects will appear lfrom the following detailed description and drawings, disclosing a specific embodiment of my invention. The

. specific embodiment herein disclosed is a pump,

particularly designed for acid service, but the inventionis not to be limited thereto,.as the invention maybe used in pumps for a wide variety of service.

The problem of liquid sealing a pump shaft for the present class of service has already been solved by my prior invention disclosed and claimed in my :prior Patent'No. 2,250,714. The method therein employed is to utilize liquid being pumped to ll anl annular cylindrical gap between the shaft and a surrounding seal sleeve, the outer end of which is open to atmosphere, and the inner end into the intake. The method is particularly advantageous during priming in that the liquid is circulated through the sleeve under no greater pressure difference than that between atmosphere and the prevailing suction and the liquid returns into the priming intake.

Uponthe pump attaining discharge pressure, the

stances, such as abrasive solidsvin the liquid being pumped, there was a tendency for the sleeveA to wear and thereby allow increase in the flow of the sealing liquid.

'I'he provision of a liquid seal for a rotating shaft has long engaged the attention of engineers and inventors. A method which early attracted the attention of designers of steam turbines was the concept of a rotating ring of liquid embracingv the periphery and margins of an intervening flange. 773,297 and 813,723, in which mercury was used as the sealing liquid. The concept here was. to produce a Vkinetic manometer in which,l under the centrifugal or inertia effect, the rotating liquid wouldprovide a pressure many times that' of gravity. A simple bell dipping into a ring of `liquid gives only the static manometer effect,

and hence is useful only for very 'low pressure differences. See United States Patent No. 991,225. In some c ases the two principles of the static and kinetic manometer are combined as in United States Patent No. 1,213,494.

`McGee Patent No. 1,949,428 proposes to provide a horizontal pump with sealing channels in which rotating discs with paddles on both sides serve to whirl the sealing liquid. Aside from the fact that a seal of the character there disclosed cannot be made to sustain full latmospheric pressure without going to excessive diameters or excessiye speeds, the complicate priming mechanism required is out of the question. Also,

for a pump in acid service, will at once be ap-- aforesaid circulation occurs underthe full differential between discharge and suction and the outilow under thediierentlal between discharge pressure and atmosphere. -While the aforesaid prior pump eliminated the rubbing friction of solid material seals previously found necessary and constituted a pronounced improvement in the art, the flow of sealing liquid both internally and externally gave opportunity for increase in overall eiliciency. Also in some special circumsuch an arrangement is whollyunsuited to acid service. yIn a modiiled form (United States Patent No. 1,949,429) the same inventor proposes to carry the. whirling ring of liquid in a rotating channel ring. The unsuitability of this form of device for a. self-priming pump, and also parent aside from the impossibility of securing suillcient manometer eifect without going to excessive diameters or speeds. The backward suction occurring in a self-priming' pump when the impeller slows down to a stop would empty the seal of vsuch a construction andv render the pump incapable of developing its suction on again starting up.

' Bischof (United States Patent No. 1,421,389) proposes the use of a chamber below the impeller to trap priming liquid. The` trap chamber is intended to provide also awhirling channel member cooperating with a stationary disc. The arrangement presents the advantage of trapping liquid for priming the seal, but the seal-is not See United States Patents Nos.

reduced or even minimum pumping effect is.

produced. In the preferred embodiment, I combine the static standpipe with the sealing ring of liquid. The chief service of the static standpipe is to conserve priming liquid during priming or for priming service.

This form of seal peculiarly cooperates with the form of self-priming pump of my invention,

the principle of which pump is disclosed in my prior United States Patent No. 1,578,236, because during priming relatively little priming liquid reaches the central part vof the impeller. Hence, although the seal itself in the preferred form constitutes a small pump, that pump is robbed of liquid during the priming operation, and the practical effect isthat not much, if any, liquid is discharged through the seal.

Upon a vacuum or reduced pressure being attained in the pump, the differential of pressure so produced tends to hold back or oppose the discharge of sealing liquid. The seal may be laid out to produce the amount of discharge desired to keep entrained solids flushed out, or it may be laid out to stop the flow of liquid altogether when a certain degree ofl subatmospherc pressure is produced in the pump. A pump and seal structure of unusually high ,efficiency and of marked effectiveness is produced. Liquid seals of the prior art to which I have abovel referred are all designed to pass no fluid while they are in operation. The seal of my invention in its preferred form is designed to pass I'he so-called sealing disk does not need to be a disk. A cylinder or a sphere, or in fact a1- most any solid having its surface generated by rotation of a loop about an axis would do, the channel in each casev conforming to the shape of the stationary body or vice versa. A disk is economical of space and material and hence is preferable.

Now in order to acquaint those skilled in the art with the manner of constructing and operating a device embodying my invention, I shall describe, in connection with the accompanying drawings, a specific and preferred embodiment of my invention and the severalA improvements which I have made.

In`the drawings:

Figure 1 is a vertical longitudinal section of a vertical self-priming centrifugal pump of my invention,taken on line Iv-I of Figure 2;

Figure 2 is a horizontal cross section taken on the line 2-2 of Figure 1;

Figure 3 is a fragmentary section, taken through the auxiliary throat on the line 3 3 liquid while in operation, but to be tight against the entry of air into the pump. This passing of liquid is permissible because a self-priming pump can always be' set above the source of liquid to be Dumped and the outowing seal liquid returned by gravity to the source. If the pump is arranged to withdraw fluid from a source which is at subatmospheric pressure,l then the pressure difference may be employed to returnv the sealing liquid to the source. Onstoppingof the pump the outflow of sealing liquid ceases.

The pump impeller, or any other driven device, might li'e below the seal. The seal may be employed for a shaft which does not drive a pump impeller. However, since the seal is intended to be able to pass liquid and to remain of Figure 2;

Figure 4 is a fragmentary cross section taken across the auxiliary throat on the line 4-4 of Figure 2;

Figure 5 is a vertical cross section through the top half of the rotor, showing the blades of the pump impeller and the blades fof the asym- .metrical seal;

Figure 6 is a top plan view with a part broken away, as indicated on the line 6 6 of Figure 5, to reveal the main impeller blades in plan and likewise the impeller blades of the seal in plan:

Figure 7 is a. fragmentary side elevation from the left of Figure 1, showing the cover for the screen and backiiow retarding valve;

Figure Bis a bottom plan View with parts broken away, showing the drain closure which may be opened to drain the seal and connected passageways; and

Figure 9 is a fragmentary sectional view through` a modified form of seal showing full length blades on the suction side and a non- -bladed gap at the outer margin of the other side with radially shorter blades on the latter side to control the lrate of passing liquid through the `seal.

The pump illustrated herein comprises as the main structural parts the pump body casting i, the lowerbody casting 2, resting on the base or stand 3, the bearing barrel l, the sealing sleeve airtight, 'liquid for that purpose should be prothe pumping side of the seal needs to be designed to give only sumcient discharge pressure to balance the possible pressure difference. It is not necessary that liquid be passed through the seal when the pressure diiference upon the seal is great enough to 'equal the pumping pressure. The seal may be kdesigned to sustain any particular value of pressure dinerence greater or less 'than one atmosphere, but it is a virtue of the present design that the pressure difference on the seal in the present pump is not greater than one atmosphere as a maximum.

and disk member 5, the rotor'G and rotor shaft designated collectively as I y The main body casting I comprises three concentric cylindrical walls, namely, the outer wall 8, which defines the outer extent of the trap chamber 9, the intermediate wall I 0 which defines the outer extent of the intake trap I2, and the inner concentric wall or sleeve I3 which mounts the sealing sleeve and disk member 5. These three walls, 8, I0 and I3, are joined at their upper ends by the top wall I4 which in this specific form is substantially horizontal. An

intake connection I5 at the right is formed in- I8 into the 'said intake trap at one side of a hollow boss or neck 28 which is integral with and extends upwardly from the top wall I4 in substantially concentric relation to the body sleeve I3 and the concentric walls I8 and 8. The passageway I1 is enlarged as at 22 to make provision for receiving the screen plate 23 shown in section in Figure 2. This screen plate sits in a bottom groove 24 in the wall of the intake passageway I1, and projects upwardly out of the opening 25 formed in the said intake connection I5. A domed closure or cover member 26 has a groove or notch at each side for holding the screen plate in position. The screen plate or strainer 23 lies transversely across the intake passageway I1 and its purpose is to screen -out or strain out coarse impurities which might accidently get into the intake of the pump. The present pump is designed primarily for chemical service, but the invention is not to be limited to that particular service. It is to be understood that the present vpreferred embodiment is not 'expected to handle liquid with entrained miscellaneous solids. The pump will satisfactorily serve for liquid containing abrasives in the nature of ne liquid borne crystals or the like. The strainer 23 is not intended to be any more than a safety device for preventing an object from being accidently passed into the pump which might injure the same. A swinging flap valve 455 has a central opening 56 therethrough which 28 which has hinge pins or trunnions 29 at each upper corner thereof is suspended in pockets or recesses 30 at the sides of and below the opening 25. This valve 28 is not intended to make a tight closure, but to retard backflow and to allow air to'pass up and over the valve and to break the vacuum in the suction line when the impeller slows down to astop. The cover member 26 has ears 29, 29 overlying thev ears 38, 38 formed on the intake connection I5, the said ears and mating iianges being provided with an interposed gasket. The ears 29, 38 are clamped together by bolts 33, 33 and nuts 34, 34 which are threaded upon the shanks of the bolts. The upper ends of the bolts are provided with threads as press the central boss 38 of a clamping yoke 31 upon the top ofthe dome shaped cover 26 to provide additional pressure between the bolts to insure a tight seal of the cover over the opening.

indicated at 35, 35, and clamping nuts 36, 36

A discharge connection 48 provides a passageway 42 communicating with the top of the separator chamber 9, and through this discharge connection 42, air is driven during priming, and

liquid during pumping. 'I'he three concentric walls 8, I8 and I3 are, at their lower ends, machined off in substantially the same transverse plane. The outer wall 8 is provided at itslower peripheral margin with a clamping ange 43, which mates with a corresponding clamping ilange 44 on the bottom casting 2, the two parts being piloted together by pilot projection 45 land pilot recess 46 with an interposed gasket 41. The

' two flanges 43 and 44 are held together by-clamping rings 48 and 49. The lower ring 49 is preferably a continuous ring,l and the upper ring 48 is preferably split into two parts, as indicated at 49 in Figure 2'. Clamping bolts pass through the two rings and clamp the two pump castings I and 2 together in sealed relation. The inside surface of the outer wall 8 has an inwardly extending fiange 52 which tends to confine the -whirling liquid ofthe priming charge during priming. The outer surface of the rim of the 64 to an adequate degree.

' 18 from the return iiow of liquid substantially leads from the bottom of the trap into the eye of the impeller 51 which is formed on the top of the rotor 6. The impeller 51 comprises open blades 58 (see Figures 5 and 6), eight straight blades in this specific instance, formed integral .at their lower sides with an annular disk 59 part of the rotor chamber as defined between the top side plate member 55 and the disk 58 constitute the impeller chamber, that is, the chamber within which the main pumping eiort vof the pump is developed. The bottom wall 63 has an apertured boss 66 which is closed by a hollow threaded .plug 61, the flange 68 of which cooperates with the end of the boss 66 through the medium of a suitable gasket to form a tight closure. The cylindrical wall 64 is .provided at the level of the blades 58, 58 with appropriate throating to constitute the pump a self-priming pump of the so-called hydraulic balance type, that is, the type which during priming permits the reentry of priming liquid into the periphery'of the blades for the purpose of forming a mixture of liquid and gas and discharging the said mixture into the separator 9. In the separator, the gas rises to the outlet 42 due both to gravity separation and whirling or centrifugalseparation which is fostered by the. design of the present pump.

The top side plate member 55 has its ilange 54 thermally shrunk upon theI finished cylindrical surface 53 of the trap wall I8. The shrink t of the flange 54 grips the top side plate member 55 firmly to the wall I8. l The cylindrical surface 69 of the top side plate member 55 fits with' a sliding fit in thel inner cylindrical surface of the wall 64 to form a closure between the top side plate members and the peripheral cylindrical wall 'I'his is in accordance with my prior Patent No. 2,244,397.

The throating through the cylindrical wall 64 which is hereinspecifically shown comprises two pairs of throats. Each pair comprises a main throat 18 (see Figures 1 and 2), and an auxiliary or priming throat 12. 'The main throat 18 in each case discharges through a gradually enf larging passageway into the separator above a horizontally extending wall 13 and the throat 12 and its expanding passageway extends down to the channel 14 formed in the lower outer an-A nular trough inthe bottom of the separator. 'I'he wall 13 extends only from the edge 15 (see Figure 1) to thev edge 16 in the same gure for each pair of throats. Between these separate horizontal walls 13, the troughlike channel 14 opens clear up tothe top of the separator chamber 9. The function of the walls 13 is to segregate the mixture discharged out of the throats free of air back through the auxiliary throats 63 and the peripheral cylin- 12 during the priming operation. 'I'he impeller is not shown in Figure 2, but it, if seated in the chamber 65, Figure 2, would rotate in a clock- I the blades 58 with substantially only mechanical clearance.

The rotor 6 consists of two functionally independent parts, although the two are joined mechanically together. The top part of the rotor is the main pumping impeller and the bottom part of the rotor provides the sealing channel.

I'he rotor is made up of the two separate me-V chanical parts threaded together, namely, the upper member which has' the annular plate 59- with a depending internally threaded flange 18 and sealing impeller blades 19. The bottom part of the rotor is formed of a tral hub 80 fitted and keyed upon the lower end of the shaft section 82. At its outer periphery, the disk 19 has an upwardly extending flange 83 which is threaded inside the threaded flange `18 to join the two rotor parts together. Between the disk 19 and the bottoms of the blades 18 which are formed on the lower surface of the annular plate 59 there is provided a narrow annular space in which is disposed the sealing disk 84 carried onthe lower end of the sealing sleeve and disk member 5.

The disk member 84 has substantially only running clearance between the said blade 18 on the top, the rotor disk 19 ning clearance is preferably of the order of alf". The depth of the sealing blades 18 is of the order of 1A and may be more or less. This sealing disk 84 is carried on a cylindrical portion of the sleeve member which is -somewhat enlarged at 85 to receive the hub 80 of the rotor disk 19. The inner periphery 86 of the disk 59 which carries the main impeller blade 58 is spaced from the said enlargement 85 on the member running clearance of the order of 31,, although this gap is not at 4all critical. portion 85 of the sleeve member 5 the sleeve member fits relatively closely to the shaft section 82, `but with a running clearance which may within practical limits be as large as desired to pass impurities. The sleeve member `5 has a shoulder which abuts against the, lower end of the body sleeve I3 and at its upper end the member 5 is threaded to receive a nut which bears against the bottom surface of the neck 20, the

l said neck being hollow. The sealing sleeve member 5, within the body sleeve I3,

is preferably slotted to provide additional storage space or standpipe space for lsealing liquid, as will be described later, andthe upper end of the sleeve erably of the order of .005.

disk 19 having a censlinger ring immediately above the end ci the sealing sleeve member 5, so that liquid rising along the shaft meets said shoulder 90v and is thrown outwardly and drained out by way of the drain pipe 89 from theA bottom of the hollow neck member 20. Immediately above the shoulder 90, a closely fitting hollow ring member 9| embraces the shaft section with al clearance pref- This ring member 9| has a flange which overhangs a stationary flange 93 formed-on the inner wall of the neck member 20. This hollow ring member 9| contains a chamber 92, the top wall of which is perforated to drain liquid from above the same, as indicated at 94, and an opening through the bottom wall is indicated at 95 for the passage of any remaining sealing liquid which is thrown off by the second shoulder 98 of the shaft section immediately above the said ring 9|. An oil seal cup 99 is seated in the bore of the top of the neck 20 and rests upon projections 98 on the ring 9|, and, if desired, a soft sealing ring 91, such as of neoprene or other elastic rubber-like material, may seal the space betweenv the said ring 9| and the bottom margin of the oilcup. 99. The sealing ring 91 may be omitted where the escape of vapor is of no moment. The oil cup 99 has an opening through the bottom, which opening is surrounded by an axially extending flange |00 on the bottom, and y the flange 83 at its outer periphery. This runwhich lies out of contact with the adjacent part of the shaft section 82. The oil drain cup 99 is provided with a drain pipe |02 which may lead off to a convenient point for collecting the oil which ispassed through the bearings. rI'he lower shaft section A82, which in the case of acid service is preferably made of corrosion resisting metal, has a reduced shank |03 Afitted into a socket |04 in the shaft section |05 which may bemade of low carbon steel. The shank |03 and the shaft section |05 may be pinned together as by the pin |06 passing through both of them. 4 An oil slinger and seal member |01 has a horizontal flange which tends to throw ofi oil passing down through the bearings, and this slinger and seal Above th'e enlarged tov fits about the shaft section 82 with a non-critical.

clearance which preferably is large enough to permit relatively free passage of entrained solids..

'I'he neck member 20 has a drain'opening into lwhich is threaded a drain pipe 89 for draining olf and returning by gravity tothe source of liquid being pumped any outfiow'ing sealing liquid. 'Ihe drain pipe 89 is shown inthe plane of the paper in Figure .1, whereas, preferably, it

VVis-disposed at'right angles thereto, as indicated in its true position in Figure 2. The shaft section 82 has a shoulder 80 which serves as a member has an axially extending flange |08 which overlaps or telescopes with the flange |00 at the center of the oil drain cup 99. These two overlapping flanges |08 and |00 which lie out of contact may be maintained underliquid seal by oil collecting in the drain cup 99 to a level below the bottom of the downwardly extending flange or skirt |08. This may be done by providing a suitable trap |09 in the drain pipe, or by erecting a trap wall in the cup 99 ahead of the drain pipe |02. Such trapped liquid is employed to seal the gap between the stationary flange 00 and the rotating flange |08 in cases where it is desired not to allow any vapors or fumes to escape into the bearings or out of the pump. In the event that the pump is to be sealed off to render it explosio-nproof, the gasket 91 is maintained in place. If the pump kis not required tobe sealed olf against the escape of fumes or vapor, the ring 91 may be omitted, and the oil trap 09 may likewise beomitted. j

The bearing barrel 4 carries a shaft' section |05 in radial bearings |I0-at the lower end, and combination radial and axial bearings ||2 at the upper end. At its lower end, the bearing justable as to height by means of three set.

screws H8. By means oi' thesey set screws the position of the rotor in the be carefully adjusted. A bearing cover I|1 is provided with an oil inlet pipe for lubricating the bearings I'I2 and IIO, and bolts I|8 clamp the cover III and bearing plate I|5 upon the upper end of the said bearing barrel 4.

The pump is mounted upon a pedestal 3 as by means of a series of threaded plugs |I9 'preferably 3 in number, threaded into bosses |20 in the bottom wall 62.- These plugs I|9 in turn fit upon recessed bosses |22v on the pedestal member 3 and are clamped to the said pedestal member by means of cap screws |23 accessible through opening |24 in the said base member 3. Base member 3 may be bolted to a suitable foundation,

or otherwise mounted. Obviously, the pump may be 'mounted -by other means than the specific provision herein shown although'v the present is ari advantageous arrangement in that through 'the three plugs II9 adjustment of the position of the pump may readily be made, and yet the pump securely attached to the base 3. i

The rotor hub 80 is held against a shoulder on the shaft section 82 by means of a threaded cap member |25. The said cap member is perforated to receive a threaded draining plug |26. The hub of the rotating disk 19 is drilled -to provide a drain opening |21, and this drain opening communicates with a radial port or passageway |20 leading to a bore formed in the lower end of the .shaft section 82, the said-bore |29 communicating with the inside f th cap |25. Thus, when it is desired to drain the-pump, the liquid may be drained out of the pump body,l which includes the separator and intake trap, by a suitable petcock or plug preferably introduced into the bottom wall 62. The rotor chamber and sleeve may be drainedly removing the threaded hollow plug 61 which opens the bottom of the rotor chamber, and by then unscrewing the central plug |26 in the cap |25. This permits the seal and the sleeve member to drain.

The pumpy is easilyserviced. The clamping rings'48 and 49 may be released byv unscrewing the bolts 50, and the top half of the pump, in-

cluding the rotor, may then be lifted off and the rotor is thereby completely revealed.

rotor chamber may The operation of the pumpv and its seal is as follows: Assume that the pump is 4provided with a suitable priming charge.k Preferably liquid is retained to about the height of the gasket 41 in normal operation. With the pump elevated above the source of liquid and the suctionconnection |5 coupledto a suction pipe the lower end of which is-submerged in the liquid to be pumped,

and the discharge 40 connected to a suitable delivery point, the shaft 1 and rotor 6 may be rotated to start the operation of the pump to prime itself automatically and thereafter automatically discharge liquid.

The priming .charge of liquid fills the lower lpart of the separator land fills the rotor chamber,

including both the portion devoted to the main impeller and the portion devoted to 'the seal. Operation of the rotor drives liquid out of the impeller and throws all available liquid out of the bottom of .the intake trap, discharging the same through all four of the throats shown Ain the present construction. f It may here be noted that the throating, and the particular form of the impeller may be widely varied. 'I'he various forms of throats and impeller blades, including curved casing with cutoff,

blades and involute type of and the various other known forms of throating and blading may be employed. However, in the that the rotor is unable to produce suilicient outward pressure to maintain an outward flow in all four of the throats, the liquid standing in the separator chamber 9 begins to flow back and quickly an organized circulation is established, consisting of the return of priming liquid through the auxiliary or priming throats 12 into the periphery of the impeller with discharge of mixture` at the main throats 10 above the plate 13, such mixture breaking down vinto liquid and gas, the gas escaping upwardly, and the liquid tending to gravitate downwardly.

The whirling of liquid around the cylindrical wall of the separator chamber 9, tends also to squeeze the gas out of the mixture by centrifugal force, as is known in prior structures of selfpriming pumps.

liquid below the pump, or at a lower hydraulic' head than the pump; The withdrawal of air by entrainment with the priming liquid and discharge of air into the separator decreases the gas pressure in the intake trap and intake passage- Ways, 0r, in to exert a suction. This operation is also termed creating a dry vacuum.

The originial priming charge has flooded the seal, and has filled all the interstices of the parts, including the space between the top plate 59 of the rotor, the top of the seal plate or disk 84, and the gap |30 between the sealing plate or disk 84 and the rotor disk 19 and the narrow gap providing communication around the outer periphery of the sealing disk 84. Depending upon the hydraulic head, liquid 'tends also to stand in the gap between the sealing sleeve 5 and the shaft section 82.

of the liquid out of the impeller chamber, and no liquid flows into the intake trap, and hence into the eye of the impeller, the seal must function on the liquid with which it started, and such liquid as was retained by the seal when the impeller 51 emptied itself. As the pump starts with assumed atmospheric pressure internally, the initial operation of the blades 18 on the rotor disk 59 exerts a pumping action upon the liquid therein containedand tends to drive the same around the periphery of the stationary sealing disk 84 through the narrow gap |30 and up along the shaft section 82 into the reservoir formed by the open spaces within the body sleeve I3. Any ex-v cess which may be driven into these spaces will run out of the top of the sleeve member 5 and into the bottom of the neck member 20, and out by way of the drain pipe'8'9 back to the source bethe body sleeve I3 tends to low the pump.

As the suction increases, atmospheric pressure lworking down upon the standpipe column of sealing liquid within the sleeve member 5 and push the sealing liquid back into the relatively wide space between the disk 59 of the rotor and the stationary sealing disk 84, whereupon, due to additional effective fluid medium or liquid medium a greater effective pumping'pressure is developed bythe' blades 18.v

designed with respect to the speed the sealing disk 84, 18 and the gap |30, herein disclosed,

The seal is so of rotation, the diameter of and the effect of the blading that, for the particular pump terms of the art, the pump beginsv and for the principle herein illustrated, the pressure which maybe developed by liquid standing at various radial positions within the blading 18, while yet maintaining a liquid seal in the gap |80, will cover the range of pressures from atmosphere to maximum practical suction.

i liquid, the operation of the sealing disk is uned to maintain a seal against the entry of atmospheric or other gases along the shaft section 82. This is accomplished by the continued delivery of liquid into the sealing blades 18 to the gap between the inner periphery of the rotor disk 88 and the stationary sealing sleeve portion 88.

Since the pumping side of the seal is now continuously supplied with liquid by gravity, the blading 18 being thereby completely filled with liquid, maximum pumping pressure is developed,

Hand, depending upon the wet vacuum then prevailing, a discharge of liquid occurs around the rim of the stationary sealing disk 8l through the narrow gap |80, and up along the shaft section 82 and. out of the top of the sealing sleeve member into the bottom of the neck member 20, and thence to the drain 88 and back to the source, or to waste if so desired. If the delivery pressurebf the seal is equalled by the suction, no outflow of sealing liquid will occur. If clear liquid only is to be pumped, the seal may be designedI to stop the outflow of liquid during liquid pumping against a predetermined suction head or a head in excess thereof. The permitted circulation keeps the seal constantly flushed with liquid and tends to washout abrasive particles which may tend to lodge in these parts. The amount of ow thus occurring varies according to the suction exerted. It is to be observed in I have also found thatfor a speed of 1750 R. P. M. la sealing disk of about '7l/2 inches diameter or slightly less will hold a vacuum of 27.5 inches. Obviously, the dimensions, speed and pressure differences may vary without departing from the principle and mode of operation herein disclosed. It is to be particularly noted that the seal is asymmetrical, in that a pumping action is definitely developed on one sidehwhile on the other side the pumping effect is reduced or substantially eliminated, with the result that when both sides are provided with equal radial depth of sealing liquid, the liquid on the side where the pumping action is developed tends to migrate over to the side where minimum pumping action is developed. Hence, where a continuous supply of liquid is available on the pumping side of the seal, liquid tends to be passed through the seal on minimum pressure difference across the seal. However,.as the pressure difference across the seal is increased, this ow diminishes, and may even be stopped, while a substantially frictionlessl liquid seal is maintained. 'I'he power absorbed in this liquid seal is relatively small, and

since liquid is constantly passing through the pump and through the seal during normal liquid pumping, there is no tendency to overheat. Also during liquid priming, the wallsv of the seal are constantly cooled by the circulating priming liquid, and the seal will not overheat unless the main body of liquid overheats, in which event the pump could not develop a suction. In practice, this simply does not occur.

Liquid creeping up along the shaft 82, paru ticularly above the standpipe or reservoir formed by the sleeves I8 and 8, encounters the radial shoulder 80 which operates as a slinger for throwing oi! any excess liquid. However, since a film may still creep upwardly, the second shoulder 86 40 is provided, and this at a greater diameter has an this connection that the pumping effect ofthe blades 18 in this type of structure needs to be only sumcient to develop the pressure difference of from atmosphere down to attainable vacuum preferably with a reasonable margin of safety. 'I'he point is that the maximum pressure which can be exerted to drive liquid up along the shaft section 88 and out of the top of the sleeve member 5 is no more than atmospheric pressure.

Hence, the -iiow through the gap |88 and out through the gap between the shaft section 82 and the parts ofthe sleeve member 8 is relatively small and does not appreciably detract from emciency of the pump.

By wayv of illustration, in a rotor of 5 inches diameter operating at 3450 R. P. M. with the sealing disk 84 of Va diameter of 4% inches diameter, the blades 18` being of substantially V4" axial width, and being approximately 32 to 40 in number, and the, gap |80 being of the order of from 95000" to 17,46", I find that a pressure difference of 28 inches of mercury may be sustained. A series of tests shows that on a seal of the aforesaid dimensions, and in a range of speeds running .from 3600.12. P. M. to- 3030 R. P. M. the dry vacuum which the seal will maintain will range from 28.14 to 27.9 inches of mercury. 7

increased throwing tendency and clears off any film which would tend to ascend. As above explained, in order to make the pump tight against the escape offumes or vapors, a yielding sealing ring 81 may be interposed between the sealing ring 80 and the oil retaining cup 88, and the oil retaining cup 88 may, through the overlap of the flanges |00 and |08, and the retention of a bodyof oil in the said cup 88, seal the passageway between these flanges against the passage of vapors through the-narrow gap between the flanges |00 and |08. The trap |08 for the oil retaining cup 88 is employed to maintain the level of oil in the said cup 88 at a point where the ilanges are sealed by oil. This special sealing of the parts may be omitted, except where explosionproof service is desired.

'I'he pump may readily be drained as above explained as by a petcock in the wall -82 and by removing the threaded plug 81 and the plug' |26 for draining-the rotor chamber and connected passageway;

. member. The blading on the moving part exerts a `control of the liquid in the corresponding side of the channel to produce a high mean angular velocity. On the other side of the channel the stationary part exerts control of the liquid in that side of the channel to prevent, or avoid the 5 production of, as high a mean angular velocity of the liquid, and hencev the kinetic effects of the liquids on the two sides is quite different.

'I'he practical Way of securing the difference is r to put blades on the live member or rotating part on the side of thefchannel where pressure is to part and the dead or stationary parts closely enough together to hinder the development of .be developed and to bring the live or rotating pressure on the side where sealing without development `of pressure is desired. This difference may be observed upon opposite sides of the side wall of a closed impeller of a centrifugal pump. The side which carries blades develops pressure and the side next the side wall or side plate does not develop pressure. Obviously, where escape of liquid is permitted'v from the low pressure side there must be a provision for supplying liquid to the high pressure or pumping Side.

It is not essential that the low pressure side of the seal be without blading for obviously blading might be disposed upon the stationary member on the low pressure side. The point is that the stationary part exerts suflicient hindrance to clevvelopment of angular velocity that that side fails to develop a mean angular velocity as great as that developed upon the high side.

The clearances are not` critical. No clearance less-than normal impeller clearance need be provided in the seal or any connected part.

The angular velocity is effective in developing centrifugal effect in accordance with the square of the effective radius. Hence differences in radial depth of liquidin the channel are of little effect at the inner radius. But as the maximum radius is approached a small increment Vof in- .crease or decrease represents a relatively great difference in effective development of pressure dilerence.

In Figure 9 I have` shown a construction of seal in which pressure is developed throughout the entire or substantiallythe entire outerpart of the .radius of the high pressure side of the sealing channel. whereas pressure is developed throughout only the inner part of the radial depth of the other side of the channel. structurally this is accomplished in Figure 9 by providing blades 'I8 upon the bottomof the disk 59 for the outer part of the full 'radial distance to the pe.

-.riphery of the disk 84 just as in Figures l, 5 and However, instead of having the narrow gap |30 between the bottom disk 19 and the stationary sealing disk-for. the full radial distance asshown in, Figures 1, 5 and 6, the disk 19a in Figure 9.I

carries blades |32 from thecentralpar-t out to a point short of the full radial extent of the stationary sealing disk 84 leaving the short dead gap |3011 at the outer margin of the said disk 84.

Y If the channel is full of liquid, the development of pressure by the blades 18 is as before. These blades produce a relatively high mean angular velocity throughout the entire outer radial extent of the disk 84 and thereby develop pressure which tends to discharge about the peripheral margin of the disk 84 over into the relatively dead space of thevgap |30awhere angular` velocity of the sealing liquid is minimized. Howeven'asjsoon as liquid enters blades |32 a counter pumping action is developed, and this tends to oppose an equal depth of liquid at the same radial distance on the upper or high pressure side. The result discharge less sealing liquid than in the arrangeences, because as soon as the pressure difference is great enough to force the liquid of the seal beyond the ends of the blades |32, these blades no longer tend to exert an equalizing pressure, and the full asymmetrical effect of the seal' of Figure l is produced. Hence this form of seal is just as effective to withstand the higher pressure differences corresponding to higher vacuums in the pump as that of Figure 1, but on low suctions the discharge of sealing liquid which occurs in the embodiment of Figure l is reduced in the embodiment of Figure 9.

The seals shown in both Figure l and Figure 9 are asymmetric seals, that is, they will resist the unsealing tendency of the atmospheric pressure tending to force liquid out of the channel and air into the intake or suction side of the impeller; but they do not provide the same resistance to unsealing in case the pressure difference be applied in the other direction. The seal of Figure 9, in addition to being asymmetric is self-compensating or self-'balancing to the extent that the bla-desr |32 plus the non-pressure developing gap I3|la` will develop as much, or substantially as much, pressure as will the top blades 18, and thereby not only resist unsealing but also reduce or wholly prevent the flow of liquid through the seal' and into the sleeve. The pump with that form of seal' (Figure 9) may be run without discharging any liquid through the outlet. 0bviously, by variation of the effectiveness of the respective blades and gaps, balance or any desired degree of uri-balance may be attained. The asymmetric seal may be employed for resisting any uni-directional pressure or asymmetrical pressure condition. The self-compensating or self-balancing form of Figure 9 may be employed where little or no runoff of sealing liquid is desired.

.I do not intend to be limited to the-details shown and described, as they are illustrative, and not intended to be limiting except as made essential by recital in the appended claims.

I claim:

l. In a. self-priming pump having a vertical impeller shaft, a rotor including an impeller on said shaft, a casing providing an intake trap having an inlet, a rotor chamber, a separator having an outlet, throating between the separator -v and the chamber permitting the re-entry of priming liquid into the peripheral part of the impeller during priming, a stationary sleeve sur-- shaft to form a driving connection between the shaft and the rotor, the upper end wall carrying the impeller blades cooperating with said throating, said upper end wall being annular, and having 'its inner periphery spaced from said sleeve by a narrow annular gap constituting a liquid inlet int the top of the sealing channel, and blade means carried on the inside of the upper'annular .is that on lower pressure differences or suctions in the pump, other things being equal, the seal will wall of the channel tending to drive sealing liquid around the outer periphery of the disk, said bottom annular wall and the bottom of the margin of the disk being positioned so closely to each other along at least the outer margin of the disk that sealing liquid cannot develop sufficient centrifugal force therein to .oppose an equal radial depth of sealing liquid within the pumping means on the upper side ofthe seal disk.

'2. In a vertical pump a rotor, a shaft therefor,

a -stationary sleeve closely surrounding the shaft but not tight thereupon, a sealing disk carried on the lower end of the sleeve, said rotor comprising a ymovable disk secured to the lshaft and lying close to the bottom wall of the sealing disk, a peripheral circular Wall and an inwardly extending flange spaced a substantial distance from the top l its inner end with the trap and' extending substantially horizontally, there being an opening, in the top wall of said connection, a swing-able back flow restricting valve having laterally extending hinge pins at its upper end, there being bearing seats for said .pins in the side walls of said connection adjacent said opening, whereby the said valve may be' inserted and withdrawn through said opening, a cover member for said opening and clamping means for said cover.

4. 'I'he combination of claim 3 wherein said cover member is domed, said cover member and said connection having a groove and a removable screen plate seated in said groove across the passageway through said connection.

5. In a pump a body casting having a top wall said top wall having Ia central opening and having an annular ange about said opening, extending inwardly from said top wall and a flanged annular bearing support extending upwardly externally of said top wal1,'a bearing barrel having a flange cooperating with the ange of said support, a removable sealing sleeve secured in said opening and clamped against said annular flange, a shaft having'upper and lower bearings in said bearing barrel and extending through said second sleeve, an oil slinger carried .by said shaft below said lower bearings, said slinger having a radially extending flange and an axially downwardly extending flange, an annular oil trap member disposed in said-annular bearing support below the oil slinger, said oil trap member having a. central upwardly extending annular `flange disposed in telescopic relation with the axially extending fiange of the oil slinger, an oil drain pipe extending laterally from the bottom of the oil trap member for draining away oil, and a seal-y ing liquid drain channel below the oil drain pipe and opening into the lower end of the annular bearing support near the top of said sealing sleeve.

6. 'I'he combination of claim 5 wherein the shaft has a radial shoulder above the top of the l second sleeve for slinging liquid creeping up the shaft.

7.-'Ihe combination of claim 5 wherein the shaft has a radial shoulder above the top of the sealing sleeve for slinging liquid creeping up the shaft, and a second radial shoulder below the oil trap member, and a removable ring disposed in sealing sleeve for slinging -liquid creeping up the shaft, and a second radial shoulder below the oil trap member, and removable ring disposed in the annular bearing support between said shoulders, said ring fitting relatively closely to the shaft, but being out of contact therewith, and being perforated for draining liquid down to the bottom of the annular bearing support, and an annular yielding sealing ring between the oil trapv member and the removable ring to prevent the escape of vapors, said oil drain member having a trap for retaining oil to form a liquid seal against the escape of vapors into the bearings.

9. In a pump, a main body casting comprising a top wall, three concentric cylindrical walls, the innermost walls defining a central sleeve, the top wall having a hole forming an extension of the bore of the sleeve, the upper ends of said three concentric lWalls joining the top Wall, and the lower ends of said walls being faced off in approximately a common plane, a discharge connection opening through the top wall into the space between the outer wall and the intermediate wall, an integral hollow annular bearing support joined to the top wall and extending upwardly, said annular support being concentric with said sleeve and having a flange about its upper rim, and an intake connection extending upwardly over the top wall and opening into the space between the sleeve and the intermediate wall, said connection being integrally joined to said annular bearing support.

l0. In a liquid seal pump, a vertical rotor shaft, a seal sleeve surrounding the 'shaft and carrying a stationary sealing disk, the rotor shaft extending through the sleeve and disk and carrying a rotor comprising a channel ring member open at the top and closed at the bottom and having a channel embracingthe rim of the Sealing disk and having blade means for developing a pumping action upon one side of the disk, the channel upon the opposite side of the disk communicating with the gap between the sleeve and the shaft,

the annular bearing support between said shoul-l I ders, said ring fitting relatively closely to the shaft .but being out of contact therewith,I and being perforated for draining liquid down to the bottom of the neck. p

8. The combination of claim 5 wherein the shaft has a radial shoulder above the top of the means providing a sealing liquid reservoir in communication with the said gap, and a liquid trapping chamber at the lower end of the sleeve and surrounding the channel ring member, said chamber trapping liquid in the channel ring member.

11. In a liquid seal pump, a rotor chamber having an inlet and having discharge throats, a vertical rotor shaft, a, seal sleeve surrounding, the shaft and spaced therefrom ,by a narrow gap, and carrying a stationary sealing disk within the rotor chamber, the rotor shaft extending down through the sleeve and disk and carrying a rotor comprising a, channel ring member open atthe top `and closed at the bottom and having a channel embracing Atherim of lthe sealing disk, and carlying on its top side open impeller blades cooperatlng with the throating, said channel ring member having on the upper side of the sealing disk vane means for developing a pumping, action tending to drive liquid around the periphery of the sealing disk, the spaceiipon the opposite side of the disk in said channel communicating with the gap between the sleeve and the shaft and comprising avnarrow gap at the periphery of the disk, said gap being so narrow that no substantial pressure is developed by the liquid lying therein when the rotor is rotated.

12. Liquid seal comprising, an interfltting annular channel member and a circular disk memi ber and adapted to receive -a body of sealing liquid means on vthe movable member comprising-'varies 'for producing in the liquid on onejside of the channel a relatively high mean angular velocity,

vand the surfaces of the members along the outer radial margin of the diskV member on the other side of the channel promoting a relatively'low mean angular'velocity of the liquid in the cordisposed inthe lower end of the chamber, said sealing member having an internal sealing channel and bearing at its upper end an annular im-y responding portion of the channel, the movable Y member on the latter side of the channel having blades extending radially to a'point short of the full'radial extent of the disk member.

13. A self-priming centrifugal pump of the ver-` l tical shaft type having a bodycomprising an impeller and seal casing provided with an inlet i opening and a discharge passageway, a separator inlet opening and -through the annular impeller and carrying at its lower end a sealing disc, a

sealing channel member embracing the disk and being carried by the shaft, said annular impeller being carried on said sealing channel member,

the said casing being closed at the bottom .'to permit liquid being trapped therein.

14. A self-priming pump of thegverncai shaft type having a body comprising an impeller casing with a central intake opening, an intake trap communicating. with said opening, the casing having peripheral throating for discharge` o f nuid and reentry of priming liquid by operation of the impeller, a separator communicating with curedto the shaft and an annular plate at its upper side, the outer peripheries of the' plates being coupled together, the impeller being supyported on said channel member, said channel member providing a channel the upper leg' of which communicates outside said sleeve member with the intake opening; of the casing, the lower leg of the channel communicating. inside the sleeve-with atmosphere whereby the maximum difference of pressure to which the seal in the' channel is subjected is full atmospheric pressure, said pump being adapted to trap a charge 'of priming liquid in the trap, casing and separator and to keep the impeller casing full when the rotor is not operating,- said sleeve extending upward above the level of liquid trapped in Athe body of the pump whereby the charge of priming liquid will not escape when the rotor is not operating.

15. Alself-priming centrifugal pump of the ver.- tical shaft type having a generally circular pump body divided yon a horizontal plane approximately midway of its height, the top part coinprising inlet and discharge connections, a central sleeve, an annular trap Wall and an exterior separator wall, the `bottom part comprising an annular wall defining a central impeller and seal chamber,v and an outer separator wall adapted 150 peller, there .being throating in the upper part of the chamber wall providing discharge and primingcommunication between the impeller and the separator, a sleeve extension secured to the sleeve of the top body portion and having a sealing disc embraced by said sealing channel, and a top plate member for the top side of 'said chamber coupled to the lower end of the trap wall, an impeller shaft journaled on the pumpbody and extending down through the sleeve and the sleeve extension and being yconnected to ther sealing member the pump body being adapted to trap and retain a vcharge of priming liquid in the cl'iarnber, trap and separator.

16; In a vertical self-priming pump of the class described'having a body comprising a trap, a separator, and an impeller and sealing chamber, a drum shaped channel member providing a seals ing channel and having a, closed head on the bottom and a centrally apertured head at the top and carrying pump impeller blades disposed in the chamber, a sleeve extending downwardly yfrom the top part of the body into the chamber and bearing a sealing disc disposed in the `sealing channel, there being atop sealing gap between .the f disc and the upper head communicating through Athe aperture with the intake sidey ofthe impeller, and a bottom sealing gap between the disc and' the bottom head of the member com-` municating with atmosphere through vthe sleeve, liquidseal blading carried by the apertured head,

said blading" extending fromv substantially the outer periphery of the channel inward to in` uence the fluid pressure in the top sealing gap' to resist suction on the seal, the gap on the bottomof the disc consisting of an outer portion of small transverse dimensions designed to prevent developmentiof pressure so that liquid will yrev main in contact with the periphery ofthe disc for sealing the same, and an inner portion lying 'radially inside the aforesaid outer portion for developing liquid pressure when the sealing' liquid in the .bottom gap extends radially inward beyond the outer .portion of the bottom gap. "f

.17; Anrasy'mmetrical self balancing liquid seal of the class described comprising a drum shaped channel member providing a sealing channel and nected to the imperforate head and extending through the annular head, a stationary sleeve surrounding the shaft and bearing a sealing disc embraced between the heads and lying in the channel,'said disc being separated from said heads by a top gap and a bottom gap, blading on the inside of the annular head, said blading acting upon liquid in the gap to develop pressure tending to force liquid across the edge of the disc into the bottom gap, and blading on the inside of the bottom head of less maximum diameter than that of the blading on the annular head for developing pressure in the bottom gap only on liquid disposed on a less diameter than that upon which the upper blading develops pressure.

18. In a pump of the vertical shaft type, the combination of a pump body comprising an impeller and seal chamber having peripheral throat` a shaft disposed in the sleeve but out of contact therewith, shaft bearing means rigid with the body of the pump and disposed above the end of the sleeve, a liquid drain cha the sleeve Iand the bearings, a sealing channel member having a channel embracing the margin of the disc, said member being carried on the shaft, and an impeller carried on the channel member and disposed in the chamberfor cooperation with the throating and with the inlet, the -top of the channel opening into the inlet and the bottom of the channel opening into the sleeve.r

19. In a pump of the vertical shafttype, the combination of a pump body having animpeller and seal chambery .a sealing channel member having a closed lower plate and an annular upper plate joined at their peripheries to provide a channel, said member being disposed in the chamber, a sleeve member extendingn into the channel member and bearing a sealing disc the margin of which is embraced by the channel, an annular impeller carried on the member and loosely surrounding the sleeve, a vertical shaft extending through the sleeve and having bearings supporting the same out of contact with the sleeve, said shaft extending through the closed lower plate and being secured thereto, said shaft having a central drain passageway inits lower end communicating with the channel below theplate, a fastening nut on the lower end of the shaft for fastening said lower plate to the shaft, a plug for closing the lower end of the passageway, there being an opening in the .bottom of the chamber through which access to the plugI and to the nut may be had, and a closure plug for said opening.

20. A'rotary liquid seal adapted to sustain a predetermined difference in pressure comprising a disk member and a rotatable channel member having a liquid holding channel embracing the outer margins of the disk member, but out of contact therewith, said channel member carrying i pressure developing blades on the low pressure side of the seal, said blades lying at the outer periphery of the disk and being capable of developing a pressure in the liquid at the periphery of the disk on the said low pressure side of the seal great enough to force liquid over into the high pressure side of the channel against the'predetermined difference in pressure far enough radially to form a complete liquid seal, said channel member having on the high pressure side only of the seal a non-pressure developing clearance ber and an voil drain chamber both disposed be Ween the top of gap at the outer margin of the disk between the side of the disk and the adjacent side of the channel and having pressure,developingblades lying radially inside said non-pressure developing clearance gap for developing pressure in the liquid of the seal on the high pressure side when the pressure difference upon the seal is substantially less than said predetermined value and the liquid is driven by the rst set of .blades from comprising a channel extending around the periphery of' the disk and overlying the margins of the disk, said seal being adapted to retain a ring of liquid in the channel in contact with the margins of the disk on both sides, there being pressure developing blades carried on the movable member, said blades extendingA radially out to substantially the periphery of the disk and being capable of developing a pressure in the sealing liquid at the periphery of the disk on the suction side of the seal high enough to force liquid around the margin of the diskagainst the full suction of the pump over into the high -pressure side of the channel far enough radially to form a complete liquid seal, said channel and disk having at the outer margin of the disk on the high pressure side only of the seal a narrow radially extending non-pressure developing clearance gap between the side wall of the margin of the disk and the adjacent side wall of the channel, and the movable member carrying pressure developing blades radially inside said clearance gap for developing pressure in liquid of the seal on .the

v atmospheric side when the pressure di'erence upon the seal is less than the full pressure difference between atmospheric and the suction which the pump is capable of exerting.

, 22. The liquid seal of claim 17 wherein that part of Ithe bottom gap which lies radially outside the blading on the bottom head is of small axial extent -to prevent the liquid therein from developing its own full centrifugal pressure.

HARRY E. LA BOUR.

Images