US2940657A - Vacuum pump and compressor - Google Patents

Description

5 Sheets-Sheet 1 Filed July 27, 1956 INVENTOR. Ham/a 5. Adams 7h 0 4 77 0'46 4 lo fe.

June 14, 1960 H. E. ADAMS vacuum PUMP AND COMPRESSOR 5 Sheets-Sheet 2 Filed July 27, 1956 N EN June 14, 1960 H. E. ADAMS VACUUM PUMP AND COMPRESSOR 5 Sheets-Sheet 3 Filed July 27, 1956 INVENTOR. Harold Li'Aafams BY v F M 12. Ju n,

ATTORNEYS June 14, 1960 H. E. ADAMS VACUUM PUMP AND COMPRESSOR Filed July 27, 1956 5 Sheets-Sheet 4 M m m m Ham/a 5. Adams ATTORNEYS June 14, 1960 H. E. ADAMS VACUUM PUMP AND COMPRESSOR 5 Sheets-Sheet 5 Filed July 27, 1956 INVENTOR.

United States Patent 2,940,657 VACUUM Pun n AND cor/nnnsson Harold E. Adams, Norwaik, Conn. Nash Engineering (30., South Norwalk, Conn.)

Filed Juiy 27, 1956, er. No. ssmsss 15 Claims. or. zet -79 This invention relates to vacuum pumps and compressors of the liquid ring type. Inpumps of this kind a pumping chamber is commonly bounded externally by a casing and internally by a ported member of circular cross-section, of either conical or circular shape. The casing is formed to provide lobes and lands in alternation. A rotor, divided into pockets or buckets, surrounds the ported member and drives a ring of water which is caused to surge outward and inward alternately, and which constitutes the pumping means. The ported member is provided with an inlet port and an outlet port for each lobe, and since there are generally two lobes, this means that four ports are provided altogether.

The central ported member is kept as small as possible in diameter in order to obtain a favorable ratio of outside to inside rotor diameter. Within this constricted central ported member, passageways are provided which conduct the mixture oi gas, vapor and liquid to each of the inlet ports and similar conduits within this same confined area conduct these mixtures from the other two outlet ports. There is, therefore, a congestion of passageways, all of which pass through one end of the limited diameter of the port member. From .the common inlet and discharge end of the ported member, the passages are extended into the head or body of the pump where the intake passages are brought together as branches of a common intake passage, and the discharge passages are brought together as branches of a common discharge passage.

In combining these passageways, rather complicated conduits result. One set of passageways must cross over the other to effect the combination. The passageways, of course, add to the complication and cost of the pump. Because of space limitations, particularly in the limiting diameter of the ported member, the velocities through these passageways are generally high and this results-in a friction drop which lowers the overall efliciency of the compressor. Some of the Work of compression developed within the compressor is utilized to expel both the excess sealing liquid and the compressed gas through the system of intricate discharge passageways. Because of the deviousness and the restricted nature of these passageways, coupled with the high frictional losses that are characteristic of two phase mixtures of gas and liquid, a great deal of the compressive energy is spent in expelling the mixture from the pump.

it is a primary object of the invention to provide for large straight-through passageways in the central port member and to eliminate the complicated conduits now necessary within the head.

To this end it is an important feature of the invention that the inlet is connected directly with one end of the central ported member, and the outlet is connected directly with the opposite end thereof. By this arrangement, the entire inner diameter of the central ported member may be devoted at one end to the less restricted passage of the vapor, gas and liquid coming from the common inlet connection as it flows directly to each of 2,940,657. Ratented dune 14, 1960 the two inlet ports within the central port member and the entire diameter of the opposite end of this same port member is available for the unrestricted discharge of the outgoing vapor, gas and liquid from the discharge ports.

It is a further important feature that a discharge impell'er, formed by the rotor hub, is provided at the discharge end of the central ported member for picking up the discharged mixture and impelling it away from the discharge ports. With this simplification, the cross-over passages and other complicated conduits are eliminated, the cost of the pump is greatly reduced, the efiiciency is increased by the reduction of friction losses, the capacity may be increased, and other important advantages are made possible.

In the improved pump, axial blades provided in the rotor hub act directly on the discharge mixture so as to remove it continuously from the central outlet port area and thus keep this area free to receive the compressed gas and liquid as discharged through the discharge ports. The work of getting this discharge mixture of liquid and gas out of the pump is done more eificiently by the direct action of the axial flow impeller than by the present indirect method of extracting energy from the compressed gas. The work of compression, which is what the compressor is used for, is therefore one hundred percent available ior its desired service, and is not penalized in getting rid of the two phase mixture from the pump structure.

It is a further object to increase the pumping capacity which can be obtained from a given rotor size. Some of the earlier liquid ring pumps were of single lobe construction. This gave but a single intake and compression cycle during a revolution. According to modern practice, the liquid ring pump is generally made of two lobe construction. It has the advantage of providing two pumping cycles per revolution, and also of providing opposed dynamically balanced displacement chambers. As previously indicated, however, an important drawback of the two lobe construction of present pumps has lain in the restricted, tortuous and complicated character of the inlet and discharge passages. 1

With the improved arrangementof passages, it is possible to provide a three-lobe construction with more adequate inlet and outlet flow capacity and with less complexity of structure than has heretofore been realized in the case of twodobe pumps. Such a construction provides three complete pumping cycles per revolution, thus increasing the capacity for a rotor of given diameter by 50% or more. In the three-lobe pump according to the present invention, it is possible to; obtain the re quired passageways through the central port member by opening, each of the three inlet ports to a common passageway through one end of the port member and discharging through the three discharge ports to a single common outlet passageway at the opposite end.

A further advantage of the new construction resides in the simplification of the separator problem. In a liquid ring compressor, the liquid seal used for cooling and for proper operation is progressively discharged with the compressed gas. Before the gas can be used, the entrained liquid must be removed. This liquid removal is conventionally done by a separator placed in the discharge line. Such separators add to the cost of the overall unit and in some cases add a parasitic drop in the line.

In accordance with the present invention, the central part of the rotor is utilized in eii ecting separation of the liquid and gas. The rotor-impeller imparts a centrifugal component to the mix'ture. While causing this mixture to be discharged into a simplecylindrical'chamher, the heavier liquid particles are thrown outward centrifugally but the lighter gas is crowded toward the center of the chamber. By placing the gas discharge in the central regiori'of' the chamber and the liquid discharge complished. The drawings illustrate a vertical arrangement of the pump, but it will operate equally as well in the horizontal position.

f 'An important field of utility of liquid ring compressors lies in the field of 'fuel booster pump units which are :required to receiveboiling fuel and transmit it at increased pressure and in a stable liquid state to the main In such a booster 10 inner and outer ends. As a bucket traverses the expand- -fuel' pump of an aircraft engine. pump unit, thebulk of the fuel is handled in liquid form by a centrifugal pump. Vapors given E by' the boiling fuel would cause the centrifugal pump to become vapor-bound, but for the fact that the centrifugal liquid pump is designed to separate and collect the vapors and f a liquid ring compressor is provided to 'draw oiicoin- .pressand recondense the vapors, and-then" deliver them fo'rward for' recombination with'thefuel output of the centrifugal pump. In this kind of unit, it is desirable that theliquid' ring compressor becapable of delivering p u the bucket andforces it out of the bucket and into the the condensate at a pressure equal, or nearly equal, to jthe output pressure of the centrifugal pump.

a 'It is an object of the invention to providea liquid ring {compressor especially adapted for a service of the kind outlined. 'To this end, it is a feature that the rotor of the liquid ring compressor is provided not only with the axial impeller'blades previously referred to, but also with impeller vanes on the side of the rotor, so that a two- "stage arrangement is made available for boosting the pressure ofthe condensate discharged by the compressor. This arrangement can also be used to advantage in other applications where the liquid has to be discharged at a 'hi gher pressure-than the compressor discharge.

Other objects and advantages will hereinafter appear. q lnthe drawing forming part of this specification: "Fig. lgis a fragmentary view in vertical section of an illustrative two lobe form of liquid ring compressor which embodies features of'the invention, the section b eingtaken on-the line 11 of Fig. 3, looking in the "direction of the arrows; V a

Fig. 1A is a view substantially similar to Fig. l but indicating another embodiment of ported member instead of the cylinder 20.

Fig. 2 is a horizontal sectional view taken 'on the line,

Z 20i Fig. 1, looking in the direction of the arrows; Figs 3'is1a sectional view takenfon the line 33 of Fig. 1, looking inthe direction of the arrows;

; Fig. 4 is a fragmentary sectional view, partly broken away, the section being taken on the line' of Fig.1,

7 i 50 cylinder 20, integral with the partitions 62, 64, 66 and 68 :looking in the direction of the arrows;

Fig.5 is a horizontal sectional view of an illustrative 'fthree-lobe liquid ring'compressor embodying features of "the inventionjarid a Figi 6 is a fragmentary view in vertical section of'a further modified form of compressor in which the rotor 'is'caused also to act as a compound impeller for maintaining' or increasing the pressure of the output delivered 7 'by the compressor. 1

V The illustrative embodiment of Figs. l to 4 comprises a driving motor 10 whose output shaft 12 extends vertical- ,ly downward beyond the casing 14 of the motor. 'A

jacket member 16 isfitted andafiixed'tothe motor casing 14 at the lower end thereof; The jacket '16 surrounds a fcompressor 18 which, in turn, surrounds the lower end 7 of the shaft 12. The jacket 16 forms an intake head or manifold for the compressor 18 at the intake side thereof and a substantial part of a separator chamber for the comipressor at the discharge side. thereof 'The inner boundary'of the compressor pumping chamber is formed by a flanged cylinder, 20 which is con- .nected by a suitable means, such as screws 22 (Fig. 2)

'itb'a'pontion of the jacket 16. 'The outer boundary of the compressor pumping chamber is formed by a casing :24 which'is shaped internally .to provide lands and lobes infalternation, there being two landsl26, and two lobes 3). 'A rotor 30 having the usual vanes 32,

2,940,657 w A g 5 42 is assembled between spring 40 and a shoulder 44 which forms part or" the inner wall part 46 of the cylinder 20. I

As is Well understood, the vanes divide the rotor into a series of pockets or buckets which are open at their ing part of a lobe, it discharges a po'rtion'of liquid into the crescent shaped space between the rotor periphery and the casing 24, causing gas to be sucked into the inner end of the bucket through an intake port 48 formed in the peripheral wall of the cylinder 20. As the bucket traverses the contracting part of the lobe, liquid from the crescent shaped space is forced back into the bucket, causing the bucket to become substantially full of liquid 'once more. Thiscomp'resses the gas at the inner end of 'cylinder' 'through' 'a discharge port 50 formed in the peripheral wall of the cylinder 20. The illustrative com- 7 pressor' follows the principles of the prior art but embodies novel structuralfeatures which differentiate it in principle of operation from compressors of the prior. art.

is sub-divided by four longitudinally extending partitions 62,64, 66 and 68; The passages '57 between' 62 and 64 and between 66 and 68 are intake passages. :They are in free communication with the intake chamber'61, but are closed oflf at their lower ends by inclined transverse webs 70. The intake ports 48 place the passages 57 in communication with the respective lobes of the pumping "chamber. The passages 59 between 64 and 66 and between 68 and62 are discharge passages. They are closed offaat their upper ends from the intakefcha'mber 61 by inclined transverse webs 72, but are open at their lower ends. The discharge ports place the respective lobes of the pumping chamber in communicationrwith the dis- ,cha;rge passages 59. An inner sleeve portion .60, of the and with the webs 70, 72, surrounds a portion of the hub 34 ofthe rotor 30, V V V ,In' Fig. lArthere is illustrated an alternate embodiment ,of pump in which the cylinder 20 is replacedby a frusto- Qconical member 2011.

All of the remainingp'ortions of theefrusto-conicalmember 20a are similar to thecylinder 20 and are similarly designated, but include'the additionof the suflix. a. Parts which are indicated both in Fig.1 and Fig. 1A are similarly designated despite the vfflCti that the shapes of some of them will have to be .altered slightly to function with the'cha'nge of shape of,

the ported member.

The rotor hub 34 is formed at its lower end with passages 74 which define canted impeller blades or vanes 76 between them. The rotor hub is thus caused to serve as an-axial impeller for transmitting liquid, vapor and gas 'from the passages 6466 and 6862 into a separating chamber 78 which is jointlydefined by the jacket 16 -and a fitting 80. "As has 'been'mentioned, the axial imlpeller serves by its rotary motion to exert a centrifugal action, so that the liquid is thrown outward and the gas fistorced toward the center. I The fitting 80 is provided ;at"i ts periphery with a threaded opening for the reception era'- liquid discharge conduit 82. An upstanding 5 part j8,witharestrictedpassage and an 'op'ening 83 at the top is provided centrally of thefitting 80 and communicates through a passage S'S'Witli a gas discharge conduit 88. The rotor hub 34 is provided with a conical umbrella-like extension 33, which extends beyond the opening83 thus deflecting liquid away from the opening 83.- The opening 83 and diameter 85'are restricted to provide high'air velocity therethrough, so as to effectively mufile the noise arising from the action of thecomprcssor. The above recited details provide a most eflicient combination gas-liquid separator and compressor muffler in a very limited space as compared with present day practice.

It will be apparent that the gas and liquid-are delivered Without resort to cross-overs or constrictions into a common intake chamber 61 located within thecylinder 20, and that they pass directly' and withoutimpediment from the chamber 61through the unrestricted intake passages 57 which lead directly to the intake ports 48 i the pumping. chamber. It is also apparent that theidisclia'rge liquid and gas pass into straight, unrestricted disch'a'r'g'fe passages 59'which lead directly to a common discharge chamber 87,-al1d that thedischar'ge from that chamber is assisted by. the axial impelleriwhichis' formed by the rotor hub 34L The above arra'ngemeht which provides for" separate intake and discharge at opposite ends of thepumprepresents a-very great simplification which results'in more efficient operation, the ability to handle'greatercapacity through the central opening, and in a suhstantia'l sa'v'ing of manufacturingcost.

Although the ppmp'hasbeen'describ'ed as'it' is shown,

with the drive shaft 12 extending. vertically, it could be used with equal'advantage if the shaft were horizontal lyl disposedi The drain 82, in such a case, would'desir-s ably be disposed atthe' lower side of-th'e'purnp and (ii rected" downward.

In Fig. disclosure is made of athree lobecompr'e'ss'or embodying features of the invention; The pump maybe generally like thepump of Figs; 1 to 4 except for dif ferences in-deta'il of the pump casing and the' central ported member, which are necessary. to the conversion from a t'w'olobe to a three lobe construction; Nogene'ral description, of the pump of Fig. 5 will be given. cerresponding reference numerals have been applied to'co'rresponding parts with the subscript a added in each his stance. Parts which are'shown' in Figs. 1 to 4'but omitted from the showing of Fig. 5 are to be understood as present in the Fig. 5 embodiment.

In Fig. 5' the casing 24a is formed to provide three lands 102- and three lobes 104, the lobes and lands being provided in alternation, and each combination of onelobe and an adjacent land extending through an arc of 120 with respect to the rotor axis as a center.

Each lobe may have its outer b'oundaryformed'a's an arc'of a circle whose center is offset from the axis'of the rotor. Preferably, and asshown, however, each lobe is made unsymmetrical with respect'to the point of maximum lobe depth, so that the intake period is extended through a greater are than the discharge'period, and the intake is efiected more gradually than'the discharge.

A central ported member a is provided with an intake port 4811 and a discharge port 50a in communication with each lobe there being three intake ports and three discharge ports altogether. The member 20a is provided at one end with a common intake chamber communicatingwith intake passages 57:: and at the opposite end with a common discharge chamber communicating with discharge passages 59a. Intermediate theend's,.the member 20a is formed with partitions 106, 108, 110, 112', 114 and 1 16. Intake passages 57a are defined by the parti-- tions 106 and 108, 110, and 112, and 114 and 116. These passages are shut ofi from communication with the discharge chamber at the discharge end of theorember 20a by cross partitions 7021;. but formed straight, direct unobstructed channels of communication from the common" ihlet'chambe'rtotherespective intake 'p'ort 43a. Discharge passages 59a are defined between partitions 108 and-110, 11 2and 114', and 116'and 106,.respective- 1y; these passages being closed on from communication with the-common inlet chamber, but forming straight, direct; unobstructed channels of communication between therespective discharge p'orts'SDiz and the common discharge chamber 87g.

The umpsof Figs. 1 m4 and of Fig. 5' are unique in the field of liquid ringpumps, in that they'provide, for the firsftime', in plural lobe pumps, intake and discharge channelswhich are neither" devious, nor unduly confined. This constitutesan important advance in pumps of two lobe" construction and makes" practically available for the first time, the advantages of pumps of three lobe constructid'n;

In Fig. 6; disclosure'is made of' a pumpj'of two lobe construction which is generally like thatof Figs. 1 to 4, but which modified at the discharge end to provide a compound centrifugal impeller as a unitary part of the compressor rotor. This type of purnp is designed primarilyrorusein circumstances requiring that the-liquid discharged from the compressor be discharged'to a higher pressure than" the compressor discharge; Such a situation may occur, for example, in booster fuel service on aircraft. The: vapor and non-condensible gasestrorn liquid fuel Which'may'have been caused to' boil because cit-altitude and because of'the suction exerted-upon it at the'intake ofthe' centrifugal booster pump, may be drawn oil from the intake of the centrifugal pump impeller'by the. compressor, compressed to the point of recondensation'andr'e'a'bsorption, and dischargedas liquid at a pressure. equal to the discharge pressure of the centrifugal liquidputn'p for. recombination with the liquid fuel forwardedby'the' centrifugal liquid pump to the main fuel Thepump of Fig; fi 'is substantially the same as the pumpofi'Figs. 1 to 4, Wiilith exception that the compressor rotorhasbeen modified to provide a two stage impeller." for the recondensed vapors. Corresponding parts have been designatedby corresponding reference numeralswith-the subscript b added in each instance, and no general description'will' lie-given; "The descriptionwinfhe confined substantially to 'thoseparts which are specifically difierent'fr'om the showing of Figs. 1 to 4.

The I Gbjdoes not form a jacket around the cornpressor' casingfz ib' but simply servesas an intakema-ni foldfor thecon'rpressor; The compressor casing 241; is sec'uredafioh'e side to the intake manifold and at the opposite side to'a supplementary casing member 12% with which it form's a centrifugal pumping chamber 122 and a discharge volute'123.' The hub 34!) of the rotor 30b is formed as before to define an axial impeller. In this case, however, the axial irnpeller blades 76!) are extended attheir' lower end to makecontinuously formed blades 132, extending'below and attached to the 'shroud l'lfi of the rotor'3tlb and" extending to a diameter approaching that of the rotor 3015. These blades 132 operate in a casing, formed by the lower piece 120 and discharge liquid into the volute' chamber 122 to a final liquid discharge 128. A peripheral seal is formed between the volute 1 22 and the lobes 26b by the labyrinth seal arrangement afiorded by "the groove 124 and flange 126. Liquid picked up by the vanes 7615 from the discharge area 50b is further centrifugally driven by blades 132' to the volute 1'22 and'discha'rged out through the final discharge 128. The non-condensihle gases and vapors-are centripetally driven to the center of'the fitting'120 where they are discharged through the threaded opening 133 and the connected gas discharge conduit 135, when desired.

Should the separatedischarge'of the non conde'nsible de'nsihle gases and vaporsma then be dischar ed: with of the liquid deliveredbythe compressoru i 1 the liquid thru the volute 122 and the 'final discharge Connection 128. V a ,7 t The blades 132 extend outward asfar as necessary to givethe finall, discharge pressure. from the 'volute 128. These blades 132, can, therefore, quite readily maintain or increasethe pressure at which the liquid is discharged by the compressor. 'Coupled with th'e impeller feature, the rotor is'caus ed to' provide a two-stage cc'ntrifugal impeller-for maintaining ortboostingthe pressure .Another very desirable feature exhibited by'this inven tion is the ability. of the vacuum pump or, compressor to handle large quantities of liquid along with the gas being compressed over and above that possible with present day designs.

Although in the forms of the inventionashown and described herein the members'20, 20a and 20b are externally of cylindrical form, the use of members, which are externally of conical form is'equally'contemplated. In such an organization the large end of the c'one is desirably made the intake end and the small end of the cone is made the discharge end. This is advantageous because thegases, and vapors occupy muchless space after jcompressi'onand do not, therefore, requireas'greata flow areafas when uncompressed.

chamber and formed a plurality'of lobes, an inner ported member of circular'cross-section forming the inner a boundary of the pumping chamber and having an intake 7 port and a discharge port in communicationwith teach lobe of the pumping chamber, 'saidin'ner ported member 5 being formed'interiorly to provide,- an intake path directly from one end of said memberv to'the intake ports, and to provide a discharge pathdirectlyifrom the discharge ports to the opposite end of saidtmember, and a 'rotor rotatable in-said pumping chambers r 2; A liquid ring'pump comprising; in combination, a

casing constituting the outer boundaryoi apumpin'g'cham- =7.

' to the opposite extremity of said membenthe rotor having a'hub disposed across the discharge extremity of said member and formed to provide passagesand impeller bladesnin alternation, for causing the rotorlhubblades to servealso as an axial dischargeimpellep. f K 1 45A liquid ring pump asset forth in claimj3," which further includes a separator at the discharge endof the ported member to which liquid and gas from the ported member are delivered by the impeller action"of the i p l er blades and inw c e qu and Je e centrifugally separated from one another under the centrifugal force imparted by said impellerblades, the separator includinga liquid discharge means in its pe- 'pheral portion and a gas discharge means in itscentral Port on.

' A-liquidring pump assetforth manna, inwhich the drive shaft and theported member are substantially vertically disposed, the intake gendofthe ported member is the upper end and, the discharge end of said member is the lower end, and which further includes a separator at. the discharge en'dp of the ported member. to which liquid and gas from the portedmember are delivered by the impeller action of the impeller; blades and in which the liquidand gas are centrifugally separated from one another under the centrifugal forceimparted by said impellentheseparator including a liquid discharge means in its lower peripheral portion and a gas discharge means inits upper'centr'al portion, and anumbrella-like bafiie covering and surrounding the mouth of the discharge means but spaced therefrom. a

.6. A liquid ring p mp 1 comprising, in' combination, a casing constituting. the-outer boundary of,a pumping chamber. and formed with a plurality of lobes, arotoroperable-inthe chamber, a'drive shaft forathe rotor, and

'axially'feiitending portcidmemberpof circular crosssection surrounding the drive shaft and'forrning the inner boundary .of the vpumping chamber, said rotor being opher and formedilwitlga plurality. of lobes, an inner ported 7 member of ;circ1 1larjcross-section 'f ormin'gthefinner boundary of the pumpingchamber andihavingan intake port and a discharge port'in communication with 'each lobe of the pumping chambensaid casing being L formed interiorly to provide a single intake chamber connecting'one end of said inner'ported .member, said innerported member haying a' substantially unrestricted intake passage leading directly from jsaidrintak'e chamber a to the respective intake ports, and said casing being formed interiorly to provide asingle discharge chamber erable in said chamber between said inner boundary. and said outer boundary, said membefhaving-an intake port and a discharge port for each lobe of the pumping cham ber, said ported. member being formed interiorly to provide an intake pathdirectly from one end. ofisaid memberfto the intake ports, andto provide a discharge path jdirectlyfrom the discharge ports IQ hflppm ite end of said; member, the rotor 'having-;a .hub disposed across the dischargeend ofsaidlmember formed 'to provide 1 passages and; impeller blades, in ,a'lternation for causing the rotor to ser ve also as anyaxiah discharge impeller,

rneans forming a centrifugal. pumping chamber at the discharge side ofthe compressorbeyond the'axial impeller, and varies carried by the rotorin saidichamber i for augmenting* the centrifugal actionfot theaxial imat the opposite end thereof said inner ported member" having' a substantially, unrestricted discharge passage flleading directly from the respective discharge ports to said discharge chamber, and a rotor rotatable in-said pumping'chamber. V V q r V I V t v 3. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamher and formedr'with a plurality of lobes, a rotor, adrive shaft for the rotor, andian axially extending portednneme ber ofcircular'cros s-section surrounding the drive shaft and forming the inner boundary of the pumping chamber, 's'aid rotor being operable in said chamber between V said inner boundary and saidol ter-boundarflsaid memher having an intake port'and a discharge port for each lobe of the pumping chamber, said ported member being formed interiorly at one end exclusively to provide in take paths directly'fromextremityof;said'member to theintake ports, and at the opposite end, exclusively to providei discha'rge' pathsvdirectly from the dischargeports provide passages and impeller blades inalternatiomfor peller, to form a second pumping stage;

- 7. A liquid ring pump comprisingfin combination; a

' casing constitutingfthe outer, boundary of a pumping chamber andformed with a plurality of lobesp a rotor operable inthe chamber, a drive shaft tor the rotor, and an axiallyextendingported member of circular cross .lsection surrounding the-driveshaft and; forming the inner boundary of the pumping chamber, said rotor being operablein said chamber between said'inner boundary and said outer boundary; said member'having an intake port and a discharge port for each lobe of. the pumping chamber, said ported member being formed interiorly to provide .an intake path directly from one end or said member to theintake ports, and to provide adischarge path directly from the discharge ports. to the opposite .end of said me'mber, the. rotor having a hub disposed across the discharge end of said member and formed to causing the rotor to serve .also'as an discharge im-, peller, means formingja centrifugal pumping chamb'er at the discharge side of the'c'ompressor beyond thetaxial impeller, and'vanes carried by the rotor in said chamber ief; augmenting' the centrifugal 'action of said axial impeller, the vanescarried. by the roton being disposed to extend outward substantially to the periphery of the rotor, to form a secondpumping stage.

8. A liquid ringpurnpcomprising; in combination, a casing constituting the outer boundary" of a compressor chamber and of a formtoprovide' at least three'lobes, an inner portedmember of circularcross section forming the inner boundary of the pumping chamber and having an intake port and a discharge port in communi- Y cation with each lobe of the pumping chamber, means forming a common intake chamber at one end of said ported member and a common discharge chamber at the opposite end thereof, the ported member being formed internally at one end exclusively to provide direct, unobstructed communication from the intake chamber to the several intake ports, and at the opposite end exclusively to provide direct, unobstructed communication from the several discharge ports to the common discharge chamber, and a rotor rotatable in said pumping chamber.

9. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamber and formed with a plurality of lobes, an inner ported member of circular cross-section forming the inner boundary of the pumping chamber and having an intake port and a discharge port in communication with each lobe of the pumping chamber, said inner boundary member being formed interiorly to provide an intake path directly from one end of said member to the intake ports, and to provide a discharge path directly from the discharge ports to the opposite end of said member, said intake and discharge paths each occupying substantially the entire cross section of the ported member, and a rotor rotatable in said pumping chamber.

10. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamber and formed with a plurality of lobes, a rotor, an inner ported member of circular cross-section forming the inner boundary of the pumping chamber and having an intake port and a discharge port in communication With each lobe of the pumping chamber, said inner boundary member being formed interiorly to provide an intake path directly from one end of said member to the intake ports, and to provide a discharge path directly from the discharge ports to the opposite end of said member, the construction and arrangement being such that the gas and vapor to be pumped pass in one axial direction along the intake path to the intake ports and in the same axial direction along the discharge path away from the discharge ports, there being no doubling back and therefore no crossing or crowding of intake and discharge paths within the ported member, said rotor being operable in said pumping chamber between said inner and outer boundaries, a central rotor hub at the discharge end of said ported member formed as an axial flow centrifugal impeller and disposed to receive and to transmit at undiminished pressure all the liquid delivered under pressure from the pumping chamber into the discharge end of the ported member, while transmitting \w'th said liquid the gases and vapors compressed in the pumping chamber and delivered under pressure therefrom.

11. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamber and formed with a plurality of lobes, a rotor, an inner ported member of circular cross-section forming the inner boundary of the pumping chamber and having an intake port and a discharge port in communication with each lobe of the pumping chamber, said inner boundary member being formed interiorly to provide an intake path directly from one end of said member to the intake ports, and to provide a discharge path directly from the discharge ports to the opposite end of said member, the construction and arrangement being such that the gas, liquid and vapor to be pumped pass in one direction along the intake path to the intake ports and in the same direction along the discharge path away 1,0 from the discharge ports, there being; nodoublingr back and therefore no crossing; or crowding," of intakeand discharge paths within the ported member, said rotor being operable in said pumping: chamber between said inner andiouter boundaries, a-central rotor hubat the discharge endofsaid ported member formed as an axial flow centrifugal: impeller and=disposed-to receive. and to transmit at undiminished pressure all t the liquid delivered under pressure from the pumping chamber into the disg charge end of the ported member, while transmitting with said liquid the gases and vapors compressed in the pumping chamber and delivered under pressure therefrom, and means forming a combined mufiler and separator chamber just beyond and around the discharge end of said axial impeller and including a central delivery means for gases of restricted flow area and a peripheral delivery means for liquid.

12. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamber and formed with a plurality of lobes, a rotor, an inner ported member of circular cross-section forming the inner boundary of the pumping chamber and having an intake port and a discharge port in communication with each lobe of the pumping chamber, said inner boundary member being formed interiorly to provide an intake path directly from one end of said member to the intake ports, and to provide a discharge pathvdirectly from the discharge ports to the opposite end of said member, the construction and arrangement being such that the gas and vapor to be pumped pass in one direction along the intake path to the intake ports and in the same direction along the discharge path away from the discharge ports, there being no doubling back and therefore no crossing or crowding of intake and discharge paths within the ported member, said rotor being operable in said pumping chamber between said inner and outer boundaries, a central rotor hub at the discharge end of said ported member formed as an axial flow centrifugal impeller and disposed to receive and to transmit at undiminished pressure all the liquid delivered under pressure from the pumping chamber into the discharge end of the ported member, while transmitting with said liquid the gases and vapors compressed in the pumping chamber and delivered under pressure therefrom, said liquid ring-pump including an outer casing which extends beyond the end of the axial impeller and in surrounding relation thereto, and a member complementary to the casing and cooperative therewith to form a combined mufiier and separating chamber, said chamber having a gas delivery means of restricted cross-section whose intake is centrally located and unitary with said complementary member, and a liquid delivery means peripherally located.

13. A liquid ring pump comprising, in combination, a casing constituting the outer boundary of a pumping chamber and formed with a plurality of lobes, a rotor, a drive shaft for the rotor, and an axially extending ported member of circular cross-section surrounding the drive shaft and forming the inner boundary of the pumping chamber, said rotor being operable in said chamber between said inner boundary and said outer boundary, said member having an intake port and a discharge port for each lobe of the pumping chamber, said ported member being formed interiorly at one end, exclusively to provide intake paths directly from one extremity of said member to the intake ports, and at the opposite end exclusively to provide discharge paths directly from the discharge ports to the opposite extremity of said memher, the rotor having a hub disposed across the discharge extremity of said member and formed to provide passages and impeller blades in alternation, for causing the rotor hub blades to serve also as an axial discharge impeller and a combined mufiier and separating chamber disposed to receive all the liquid, gas and vapor delivered by the axial discharge impeller, and including separate discharge members for liquid and for gases, respectively, the latter being sufliciently restricted to induce a-high gas velocity for efiectively muflling' noises arising from the compressor action. V a. 3

:14. A liquid ring pump as set forth in claim 1 in which the "inner ported member is externally cylindrical in form, and a rotor rotatable in said pumpingchamber. j

15; A liquid ring pump as set forth in claim 1 in which the inner ported member is externally frusto conical'in formk Nash Mar. 31, 1914 Corneil: May 21, 1940 Adams Dec. 3, 1940 Smith -2 Aug. 7, 1945 Chase Nov. 28, 1950

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