US2939398A - Pump - Google Patents

Description

June 7, 1960 J. P. HEISS PUMP Filed Dec. 2, 1954 h N 2 m kx "a m 4 l N u f R N w n 6N t? si C l /v 24g 2 Sheets-Sheet 1 June 7, 1960 J. P. HEISS PUMP 2 Sheets-Sheet 2 Filed Dec. 2, 1954 fnl/Email* c/amv l? HE/ss Q4 1%@ ,w m .zw/@ 5g Z22/5.

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PUMP

JohnA P; Heiss, Flint, Mich.,` assignor to Thompson Ramo WooldridgeA Inc., a corporation of Qlxio FiledDec. 2, 1954, Ser.No. 472,587

3 Claims.,u (Cl. 103`- 42)`,

The present'-invention relates to pumps ofthe angularl piston cylinder. type which areadapted tobe drivenf through a very wide ran-ge of speeds and' still deliver substantially constant flow at a predetermined pressure. More particularly, the inventionv relates to an angular pis,- ton and cylinder block pump which prowides means -for initial loading on the cylinder blocks to insure positive porting until the pressure in the pressure zone between the cylinders reaches the desired value.

The pumps of this invention employ angularly' disposed pistonsv andcylinder blocks, the cylinder -blocks rotating in a housing abou-t intersecting axesr with the' pistons interconnecting ,the lblocks and permitting relative movement between the cylinder blocks. This structure has been improved with regard to its efficiency at high pres. sures -by producing what is known as a balancedu arrangement. Inv pumpsv of the balanced type, a pair of angularly disposed cylinder vblocks are mounted for. rot-a.- tion in a housing, the housing lbeingclosed at .each end -by means of a pair of end heads against which theouter` endfaces of thecylinder blocks are arranged to engage. To accommodate variations in operating conditionsuthe cylinder blocks are mounted sov as to permit a slight axial movement of each Iblock under the iniiuence of prevailing Vhydraulic pressure. This slight axial displacementl permits a film of the Working huid to be maintained in the spaces between theouter ends of` the blocksand the end heads with which they are associated. Means are provided to supply` this. space,v with uidgpressure axially in the block in opposition to the axial thrust developedin the block by fthe uid pressure in the central portion of the pump between the inner facesof the two blocks'. By a inventionmay include. a housing vv11 havingA a pair of proper relation of the areas upon which thesev two opposing forces act, a balance can be effectedin. which each cylinderv block is rmlyseated. against its iiuid film, but the force exerted against the iilm is insufficient to rupture the film.

While the type of pump described has been Afound to be quiteV satisfactory in normal operation, some diiiiculties have arisen in starting the pump properly, particularly when viscous fluids are being pumped'. As a result, some means had to be provided for priming the pump until lsuch time as the normal operating pressures within the pump housing lwere reached.

In view of the foregoing, `an object of the presentinvention is to provide an improved angular piston and cylinder block type pump of the balanced type with means for insuring'elicientV operation while pressure is being built up in the pump.

A still further object `of the present invention is to provide an improved angular piston and ,cylinder block typepump` with a. spring activated cylinder loading device which provides initial loading on thecylinder blocks to insure positive porting` within the pump until the operating pressure is reached.

Other objects and features of this inventionwill be apparent to those 4skilled inthe art `frornthe following detailed description of the annexed sheets of drawings ice which, byyvay ofpreferred embodiment only, illustrate III-III of 4`FigureV l;I

Figure 4' is a view in perspective ofoneof fthe cylinder blocks ofgthe present invention, illustrating `seti/'eral pistons inthe block; l,and

Figure 5' is a cross-sectional yiew taken, substantially alongthe-lineV-V of Figure il.

AsA shownin thedrawings;V s

As hestseenin Figure 1,l the pump 10, of the present cylindricalihores 12' and vI'S'Vextending inwardly from. iopposite ends thereof and being disposed in angular relationshipso as: to dene an angleof less than 180 and morei than 90g-therebetween, the preferred angle being' aboutlllSOf'. V A pairof shoulders 14 and 15 define the ends of the bores 12`and 13 respectively, leaving a pressure; chamber ,'16l hetVIeen4 theV shoulders.

Reeeifx'recl.A within the bore. 12 in slidable relation is a cylindrical bloclif17, and a second cylindrical block 18 is received.,withinfthelbore 1.3. As evident from Figure f1, the length` of'theblocks 17 and 1:8 issomewhat shorter` than .thedepthoffthe bores 1 2 endl 1.3, Soi that the blocks, i117 t andlg are free. to move axially "a limited amount with` in*` .the housing,l permitting ,the'establishment of a liquid' il'm at'the outer ends' of" the blocks 1,7` and 18 as previ? ously discussed..

Eachofltlie blocks., w17V and 18 has a plurality of .holes 19 extending, axially ofthe block and disposed in equally spacedY relationshipV about the lblock ,(-s'ee Figure 5). These,hol`esz 19 receive the. Vlegs of hollow angle typev pistons. 20. 'dI-The Ipistons 20 are, s o arranged as to have their. 'angu-la'nbends disposed in the pressure space 16 betweenthebIocks 17 an,d,18,. Thelegs of' the pistons 20 areof sutlicient length so `as Vto extend'close to the outer end faces`17a-, and 18a`of 'theI cylinders 17 and 18, respectivelyfwhcn. thencylinderblocks 17 and 18 are disposed substantially adjacent.each other.4

'Theend'softhe housing y1`1 'arefclosed by ,opposedA end heads ,241.fand'I25, lrespectively,with gaskets 26 being ineluded betweentheend headsrand the housingto seal the interior offthej body.: `Arplfurality of spacedbolts 27 serve to', secure the'fend heads'424 and 25 ontothe housing 11.

4llie end .-face.,17,a, .offthe cylinder, block 17I cooperates" withaned. face'oflthe endliead 24. The end face 31 has a kidney shaped r,port BZ'Jarranged to co'mmur'iicat'eV with the` holes 19 along ithose :reg-ions ofthe blocks lwhere theinner end faces ,17h and 118b'par'e spaced apart the greatest amount,` and where` the endsnof the pistons 20' are spaceds'ubstantially from the outer end'facesV 17a and 18al of the lrespective blocks. ,n The'port 32 communicates. with a passage 33 inthe head Mend with aninlet'boss 34 of the pump. i Y

Asecond kidney V,shaped port 36 `communicates'withY theholesf of `theylindl;block vinthe regions Where the -inner .faces' ofA theblocks arecl'osest together, and Where tlieweridsuotfthe pistons are closely adjacent the' respective 'endn faces.v The "port '3 is v`conr`ie-cted through avpassage .37, in the Aend headk 24 ivitlianoutlet boss` 38.

Patentes! June 7, .196.9`

the enlarged end; bore 17d is proportioned relative to the diameter of the end face 17a so as to provide a balanced pressure condition within the pump casing by allowing for a thin lm of hydraulic uid between theV end face 17a and the end head 24 which exerts'a pressure in opposition to that applied to the cylinder block 17 in the pressure chamber .16.

Figure 3 illustrates more particularly the structure of the end head 25 which cooperates with the cylinder block 18. As seen in this figure, the end head 25 has an end face 39 arranged to confront the outer end face 18a of the cylinder block 18 and is equipped with a kidney shaped port 41 opposing the port 32 in the opposite end head and an outlet port 42 opposing the port 36. Thus, the opposite ends of the holes 19 simultaneously register with the ports 32 and 41 in the retracted positions of the pistons while the opposite ends of the holes 19 simultaneously register with the outlet ports 36 and 42 in the extended positions of the pistons. l

Extending inwardly from the outer face 18a of the cylinder block 18 is a splined recess 45 which receives a splined drive shaft 46. A counterbore 47 surrounds the recess 45 to determine the effective end area of the recess.

The counter bore 47 is vented to the inlet port 41 through Y a groove 49 in the end face 39. When the splined teeth of the drive shaft 46 engage in the recess 45, passages are provided which join the counterbore 47 with the bottom of the recess so that the effective area of the end face 18a is proportioned relative to the effective area of the inner end lface 418b of the block, for the requisite balance condition in which the outer face 18a is rmly disposed against a ilm of the working fluid.

A pair of bearings 51 and 52 support the shaft 46 for rotation in the end head 25. A collar 53 is mounted on a shaft 46 between the bearings 51 and 52 to apply any axial thrust on the shaft against the bearings, of the assembly` is provided with a cover 55 whichk re-v ceives a shaft seal 56 therein.

In accordance with the present invention, means are A provided -to insure initial loading on the cylinder blocks 17 and 18 and thereby provide positive porting 'of the liquid until Ithe pressure in the pressure chamber 16 between the cylinder blocks builds up to the operating pres sure. These-means may take the form 'of fa contact 58 which is tightly received in a relatively small diameter axial bore extending into the inner face 18b of the block 18, in cooperation with a detent mechanism on the cylinder block 17. The latterv may include a closed end hollow sleeve 59 having an enlarged annular flange portion 60 seated against the inner face 17b of the cylinder block 17. Disposed within the sleeve 60 is a projecting pin 61 having a tapered nose portion larranged to engage the contact 58 and thereby apply axial pressure against Ithe contact. The pin 61 is generally circular, but, as illustrated in Figure 5, it also has aflat portion 62 which provides a vent between the pressure chamber 16 and the outer face 17a of the cylinderblock 17. y A spring 63 has one end bottomed against `the face of the 'sleeve 60, andis arranged 'to urge the tapered nose portion of the pin 61 into engagement with the contact 58.

Alternately, the loading means may take the form illustrated in Figure 1A. As there illustrated, the block 18 may include an integral, conically shaped head 58a which rides against a conically shaped face 61a of the sleeve 59. As illustrate, the two conically shaped portions abut along a line extendingfrom the apex to the base of the two cones. This type1 of construction provides a somewhat more positive engagement between the elements of the loading mechanism, and for that reason. is preferred over the embodiment illustrated in Figure l.

With the arrangement described, the cylinder blocks, 17 and 18 are urged positivelyV against the end heads 24 and so that the cylinderlblocks are'iseated in sealed relationship with-the end faces of the pump. As a result,

The end positive porting of the pump is provided even upon building up to operating speed.

In normal operations of the device, the pressure chamber 16 receives lluid under lpressure from the discharge ports 36 and 42 of the pump through leakage paths afforded between the holes 19 and the pistons 20 and also between the bores y12 and 13 and the cylinder blocks 17 and 18. These same leakage paths are also open to the inlet ports 32 and 41 so that the pressure chamber 16 is normally at a pressure about midway between the inletand the discharge pressure of the pump. The pres-p' sure acts on the inner end face 17 b and 18b of the cylinder blocks 17 and 18 to urge the blocks against a llm of iluid separating the blocks from the end heads 24 and 25, this hydraulic pressure acting in combination with the pressure provided by the spring 63. The recesses 17d and 47 in the outer end faces of the two blocks are vented to pump inlet pressure while the remaining areas of the end faces are not. These remaining areas are less than the areas of the inner end faces 17b and 18h, leaving a diierence -in area which controls the pressures of the cylinders against the uid lms disposed between those cylinders and the sealing end 4faces 31 and 39.

In order to minimize the wear and noise which may occur as the pump discharge pressure increases, the pump of the present invention may employ a ow metering valve system of the type described in Dudley application Serial No. 416,793, entitled Pump" and iiled March 17,l 1954, this application being assigned to the sameassignee as the present application.

The improved ow metering valve system includes a relatively small diameter passage v66 formed in the housing 11 and communicating with the pressure chamber 16. The housing 11 is also formed with a bore 67 which intersects the passage 66 and which slidably receives a thimble type valve 68. The discharge port 38 of the head 24 is connected by means of a tube 70 with one end of the bore 67, and another tube 71 communicates with the other end of the bore 67 for discharging fluid from the pump.

The valve 68 is free to slide within the passage 67 up to a stop dened by a shoulder 72 in the bore 67. A spring 73 has one end bottomed on the tube 71 and its opposite end extending within the valve member 63 to urge'the valve 68 away from the shoulder 72. A peripheral groove 74 is arranged to register with lthe passage 66 when the valve 68 -is suitably aligned with said passage.

A predetermined pressure differential is provided between the tubes 70 and 71 by the inclusion of an orifice 76 in -one end of the valve member 68.

The housing 11 also has a bore 76 which provides Ya seat for a ball 77 which, in its closed position, closes off the bore 76 from a recess 78. The recess 78 is vented to the atmosphere by means of a port 79, and a spring 80 bottomed against an end cap 81 normally ur'ges'the ball 77 into a port closing position. With this arrangement, a check valve is provided for venting the bore 67 downstream from the valve 68 whenever the pressure exceeds a predetermined amount. In this case, the ball 77 becomes unseated and the passageways 76 and 79 will be placed in fluid communication to vent the excess pressure from the tube 71.

Should the pressure differential across the oriiice 76 exceed the predetermined maximum, the'valve 68 will move under the influence of the pressure against the action of the spring 73 and will become bottomed against the shoulder 72. In this position, the groove 74 is placed in -uid communication with the passage 66 thereby venting the pressure chamber 16 either to atmospheric pressure or to the pump inlet pressure. As the chamberV 16 is vented, the resulting reduction in pressure in the chamber permits the cylinder blocks 17 and 18 to move inwardly toward the shoulders 14 and 15.l The axial movement of the blocks under these conditions is suicient to overcome the bias provided by the `spring 63, so that the outer faces 17a and 18a of the box become spaced from the sealing yfaces 31 and 39 of the end heads and the seal provided by the film of working uid is broken. As a result, the inlet and outlet ports in the end heads are placed in uid communication and uid ow will occur between the ports. In this condition, the pump is automatically regulated to deliver only a predetermined flow rate since flow rates in excess of the desired amount will result in shifting of the valve 68 and a cutting down of the tlow through the tube 70l even when the pump speeds would ordinarily call for a higher ow rate.

From the foregoing, it will be seen that the pump of the present invention provides for la positive sealing of the cylinder blocks against the end heads so that the pump draws uid even though it had .previously been stopped with the cylinder blocks located off their end seats. It should be noted that the described system works particularly well with the balanced cylinder block arrangement. In the absence of the pressure balancing, the inclusion of the spring mechanism for sealing the cylinder blocks against their end `faces would not be practical because the spring would have to very substantial, making the pump harder to start even to the point of setting up and scoring the parts.

It will be evident that various modications can be made to the described embodiments without departing from the scope of the present invention.

I claim as my invention:

l. A pump of the angularly related piston and cylinder type which comprises a housing having a pair of opposed cylindrical bores in angular relation, spaced opposed cylinder blocks rotatable and laxially shiftable in said bores, each cylinder block having a ring of axial holes therethrough, angle pistons each having legs slidable in the holes of both blocks and spanning the space between the blocks, end heads on the housing closing the outer ends of said bores, the space in the housing between the opposed cylinder blocks being subjected to discharge pressure of the pump through leakage paths in the pump for urging the blocks outwardly into sealing relation with the end heads, at least one of said end heads having inlet and outlet ports lassociated therewith `and communicating with the outer ends of the holes in the block adjacent said head and separated by sealing surfaces on the outer end of said block and said head, means venting a portion of the outer ends of both block-s to inlet pressure to create a lesser yarea on the blocks exposed to outlet pressure at the outer ends of the blocks than at the inner ends of the blocks to control pressures of the blocks against the end heads for leaving therebetween a film of fluid being pumped under Vall operating conditions of the pump, and opposed spring loaded contact means carried by the blocks at the axial centers thereof `and riding against each other in the space between the blocks to urge the blocks toward the end heads even when the space between the blocks is not pressured.

2. A pump of the angular piston and cylinder type which comprises a housing having interconnected cylindrical bores disposed in angular relation and extending outwardly from each other, `a cylinder block rotatable and axially shiftable in each bore, said blocks being spaced apart and each cylinder block having a plurality of axial holes therethrough, angle type pistons having legs slidable in the holes of both blocks and extending across the space between said blocks, end walls spanning the outer ends of said bores each having an inlet port and an outlet port selectively communicating with the outer ends of the holes in the adjacent block, cooperating sealing faces on said end walls and outer ends of the adjacent cylinder blocks for separating the inlet and outlet ports, the space in the housing between said blocks being subjected to discharge pressure of the pump through leakage paths in the pump for urging the blocks outwardly into sealing relation with said end walls, means venting a portion of the outer ends of both blocks to inlet pressure for creating a lesser area of the blocks exposed to outlet pressure at the outer ends thereof than at the inner ends thereof for controlling pressures of the blocks against said end walls to leave therebetween a lm of iluid being pumped, a contact head at the axial center of one block extending into the space between the blocks, a contact member carried by the other block of the axial center thereof, and means urging said contact member against said head for urging the blocks apart and against the end Walls to separate the inlet and outlet ports even when pressure in the chamber between the blocks is not suilcient to maintai-n the sealing faces of the Iblocks in lsealing relation with the end walls.

3. A pump of the angular piston and cylinder type which comprises a housing having a pair of connected cylindrical bores disposed in angular relation, -a cylinder block rotatable and axially shiftable in each bore, said bloc-ks being spaced yapart and each block having a plurality of axial holes therethrough, angle type pistons having legs slidable in the holes of both blocks and extending across the space between said blocks, end Walls spanning the outer ends of said bores each having an inlet port and an outlet port selectively communicating with the outer ends of the holes in the adjacent block, cooperating sealing faces on said end -Walls and outer ends of the adjacent cylinder blocks for separating the inlet and outlet ports, the space in the housing between said blocks being subjected to discharge pressure of the pump through leakage paths in the pump for urging 'the blocks outwardly into sealing relation with said end walls, means venting a portion of the outer ends of both blocks to inlet pressure for creating a lesser area of the blocks exposed to outlet pressure at the outer ends thereof than at the inner ends thereof for controlling pressures of the blocks against said end walls to leave therebetween a film of fluid being pumped, one of said blocks having an axial bore opening to the space between the blocks, a spring loaded nose member slidably mounted in said axial bore and urged toward the other block, and said other block having a contact head at the axial central portion thereof receiving said nose `in riding contact therewith whereby the spring loaded nose will urge the blocks into sealing engagement with the end walls to separate the Iinlet and outlet ports even when the space between the blocks is not pressured.

References Cited in the file of this patent UNITED STATES PATENTS 1,678,556 Copson July 24, 1928 1,970,679 Walker et al Aug. 21, 1934 1,996,889 Thomas Apr. 9, 1935 2,073,710 Rayeld Mar. 16, 1937 2,117,521 Stevens May 17, 1938 2,215,138 Stevens Sept. 17, 1940 2,284,111 Vickers May 26, 1942 2,284,169 Robinson May 26, 1942 2,353,802 Zimmermann July 18, 1944 2,364,301 MacNeil Dec. 5, 1944 2,412,835 Robinson Dec. 17, 1946 2,459,786 Beaman et al. Ian. 25, 1949 2,501,054 Huber Mar. 21, 1950 2,608,158 Beaman et a1 Aug. 26, 1952 2,619,041 Born Nov. 25, 1952 2,699,123 Bonnette et al Ian. 11, 1955 2,779,296 Dudley Jan. 29, 1957 FOREIGN PATENTS 267,265 Great Britain Mat. 17, 1927

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