US3126834A - bursak - Google Patents

Description

March 31, 1964 G. J. BURSAK ROTARY PUMP 5 Sheets-Sheet 1 Filed March 22, 1962 \NVENTOR GEORGE J. BURSAK ATTORNEY March 31, 1964 G. J. BURSAK 3,126,834

ROTARY PUMP Filed March 22, 1962 5 Sheets-Sheet 2 3! INVENTOR /9 D 4 GEORGE J. BURSAK AT TORNEY United States Patent 3,126,834 ROTARY PUMP George I. Bursalr, 5601 W. Auer Ave, Milwaukee 16, Wis. Filed Mar. 22, 1962, Ser. No. 181,582 2 Claims. (til. 193-126) This invention relates to rotary pumps of the type which employ cooperating driven impellers to positively displace material within a pump chamber, and particularly to a rotary pump of this type in which the driving mechanism for the impellers is completely sealed from the pump chamber to prevent contamination of the material being pumped.

Rotary pumps of the type considered herein normally include a pair of impellers having parallel axes of rotation. The impellers are provided with mating peripheral surfaces and rotate in opposite directions within a pump chamber having surfaces which cooperate with the peripheral surfaces of the impellers. Rotation of the impellers within the pump chamber draws material to be pumped through an inlet port which communicates with the pump chamber and forces the material, under pressure, through an outlet port which also communicates with the pump chamber. Means are provided for driving the impellers and such means normally include a pair of shafts which mount the impellers, one of the shafts being driven from an external source and the other shaft being driven by intermeshing gears located on the two shafts. The pump chamber and inlet and outlet ports are included within a pump casing which is separate from a gear housing which supports the pair of shafts in parallel relation as well as providing an enclosure for the intermeshing gearing. The shafts project outwardly of the gear housing at one end and are received in openings provided in an opposed face of the pump casing so that they may mount and engage the impellers.

Such rotary pumps produce a positive displacement of the material being pumped and afford an economical device for pumping liquid and semi-solid products. Rotary pumps have been used to particular advantage in the handling of food products of all varieties. It is obvious that in such applications, rotary pumps must be capable of meeting rigid sanitary standards to insure that the products being handled are not contaminated during the pumpiim operation. To this end, rotary pumps of the type considered herein are designed for simple disassembly of all parts which come in direct contact with the pumped product. Generally, this means that the impellers and pump casing which includes the pump chamber and inlet and outlet ports are adapted for simple removal so that they may be periodically cleaned and sterilized.

Regardless of the care exercised in the cleaning of the impellers and pump casing, there remains in present rotary pumps several points of potential contamination to the product. First, it is necessary that the gear casing contain a lubricant to protect the intermeshing gears contained therein. Since both the driving and driven shafts project outwardly of the gear housing at one end, there is a tendency for the lubricant to leak out of the gear housing at the points where the shafts are journaled through such housing. If this lubricant is permitted to travel unimpeded along the shafts, it will ultimately find its way to the pump chamber Where it can contaminate the product.

A second point of possible contamination in present rotary pumps is found in the impeller mountings. Commonly, each of the impellers has been provided with a continuous axial bore which removably receives the extending end of one of the shafts. The shafts and inner surfaces of the impeller bores are splined or keyed to insure that rotation of the shafts will be imparted to the impellers. In such construction the impellers may be slipped off of the shafts and the pump casing may be removed from the gear housing for cleaning of the impellers and pump chamber. It is also necessary to clean the ends of the shafts which enter the pump casing. However, such cleaning cannot be effectively accomplished since the shafts are not removable and it is practically impossible to clean the splined or keyed portions of the shafts with the result that the attendant corners act as repositories for bacteria. During the pumping operation, deleterious substances which collect on the shafts may be drawn into the pump chamber and result in contamination. One proposed solution to this problem has been to permanently join the impellers to the shafts and provide for the removal of the entire shaft and impeller for cleaning. This results, however, in requiring an unnecessarily complex driving connection betwen the removable shafts and between the driving shaft and the source of power, and it is necessary to replace shafts when it is desired to change impellers.

In comparison, the rotary pump assembly of this invention effectively eliminates the possibility of contamination of the material being pumped. This is accomplished by completely enclosing the portions of the shafts which project into the pump chamber within the impellers which are removably mounted thereon. An integral portion of each impeller surrounds the portions of the shafts which project within the pump casing. Sealing means are provided between the impellers and the pump chamber thereby completely sealing the shafts from the pump chamber so that lubricant from the gear housing and deleterious substances accumulated on the shafts cannot find their way into the pump chamber. The practice of this invention further contemplates the construction of a rotary pump in which the sealing means between the impellers and the pump chamber are accessible for simple manual removal for cleaning.

Accordingly, it is a principal object of this invention to provide a rotary pump in which the pump chamber is completely sealed against the entrance of foreign substances.

It is also an object of this invention to provide a rotary pump having a pair of mating impellers driven by driving means which includes a pair of shafts mounting said impellers and in which the impellers shield the shafts from contact with the material being pumped.

It is a further object of this invention to provide a rotary pump in which sealing means between the impellers and pump chamber are capable of simple manual removal for cleaning.

The foregoing and other objects and advantages of this invention will appear in the description to follow. In the description, reference is made to the accompanying drawings which form a part hereof and in which there is shown by way of illustration a specific form in which this invention may be practiced. This form will be described in detail to enable those skilled in the art to practice this invention but it is to be understood that other embodiments of the invention may be used and that changes in the embodiment described may be made by those skilled in the art without departing from the true scope of the present invention. Consequently, the following detailed description is not to be taken in a limiting sense and the scope of the present invention is best defined by the appended claims.

In the drawings:

FIG. 1 is a view in horizontal cross section of the rotary pump of this invention,

FIG. 2 is a view in section taken along the plane represented by the line 22 in FIG. 1,

FIG. 3 is an enlarged detail of the sealing means illustrated in FIG. 1,

FIG. 4 is a View in section taken along the plane represented by the line iiin FIG. 1, and

FIG. 5 is a viev in section taken along the plane represented by the line 55 in FIG. 4.

Referring to the drawings and particularly to FIG. 1', the rotary pump of this invention includes a gear housing having a back wall 11 provided with a pair of spaced bores 12 and a front wall 13 provided with a pair of spaced bores 14 aligned with the bores 12 in the back wall 11. Each of the bores 12 in the back wall 11 receives a double row, sealed bearing 15 and single row sealed bearing 16 is provided in each of the bores 14 in the front wall 13. A driven shaft 17 is journaled through one pair of aligned bearings 15 and i6, and the driven shaft 17 projects outwardly of the front wall 13 and terminates in a reduced portion 18 having a cross sectional configuration best seen in FIG. 4. The driven shaft 1'7 also extends outwardly of the back wall ll for connection to a suitable source of rotational motion such as an electric motor (not shown). An idler shaft 19 is similarly journaled in the second pair of bearings 15 and 16 and, as with the driven shaft 17, projects outwardly of the front wall 13 where it terminates in a reduced portion 2t? having a similar configuration to the reduced portion '13 of the driven shaft 17. A spur gear 21 is mounted on the driven shaft 1'7 within the gear housing 10 and is rotatably held on the shaft 17 by suitable keying (not shown). A similar spur gear 22, which meshes with the gear 2-1, is keyed to the idler shaft 19. The gears 21 and 22 are identical so that rotation of the driven shaft 17 by a power source will cause the idler shaft 1% to be rotated at the same speed as the driven shaft 17 but in an opposite direction.

A pump chamber unit is formed from a pump casing 23 and a closure plate 2d. The pump casing 23 is seated upon the front Wall 13 of the gear housing It; by a pair of dorwels 25 which are provided on the front wall 13 and which project outwardly to be recevied within cooperating holes provided in the gear casing 23, as shown in FIGS. 1 and 2. Similarly, the closure plate 24 is seated upon the outer face of the pump casing 23 by dowels 26 provided on the pump casing 23 and which project outwardly thereof to be received within holes provided in the closure plate 24. Studs 27 project outwardly from the exterior face of the front wall 13 of the gear housing 10 and are journaled through holes 28 provided throughout the depth of the pump casing 23 and aligned holes 29 provided through the closure plate 24. The studs 27 extend entirely through the pump casing 23 and closure plate 24- and terminate in threaded ends which cooperate with wing nuts 30 so that the closure plate 24- and the pump casing 23 may be releasably secured to the gear housing It) to form a unitary pump assembly.

The pump casing 23 is provided with a pair of circular cylindrical pockets 3-1 having a depth less than that of the pump casing 23 to define an end wall portion 32 and the axes of pockets 3]. are spaced apart a distance equal to the spacing :of the shafts 17 and 19. The pockets 31 intersect to form a continuous pump chamber 33 in cooperation with the closure plate 24. An inlet port 34 to the pump chamber 33 is provided through the pump casing 23 in line with the intersection of the pockets 31, and an outlet port 35 is provided in the pump casing 23 on the opposite side of the pump chamber 33 also in line 'with the intersection of the pockets 31. Threaded portions 36 are provided to receive conduits leading to the inlet port 34 and from the outlet port 35.

A pair of similar, single lobe impellers 37 and 38 operate within the pump chamber 33 defined by the pockets '31. Each of the impellers 37 and 38 is preferably formed of a metallic hub 39 which is provided with a central axial bore 40 adapted to receive the projecting portion of the respective driven shaft 17 and idler shaft 19. The central, axial bores 4% do not extend throughout the entire length of the hubs 39, but rather terminate short thereof to define end seal walls An insert 42 is press fitted Within each central bore '49 and against the end seal wall 41, and the inserts 42 are provided with bores having a configuration which matches the peripheral configuration of the reduced portions 13 and 2%} of the shafts '17 and 19, respectively (see FIG. 4). Roll pins 43 are provided within radial bores in the hubs 39 and the roll pins 43 extend into shallow holes provided in the inserts 4-2 to prevent rotation of the inserts 42. within the central bores 46). Each of the hubs 39 includes a sleeve portion 44 which extends laterally from the face of the impeller 37, 33 opposite the end seal Wall 41. The inside diameter of each sleeve portion 44 acts as a continuation of the central bore 4%).

Lobe portions 45, preferably formed of a corrosive resistant rubber, are molded about the hubs 39. The peripheral surface configuration of the lobe portions 45 is known in the art and constitutes no part of this invention. Suffice it to say, therefore, that each of the -lobe portions ,5 has a maximum radius portion of a dimension equal to the radius of a pocket 31, and a minimum radius portion of a dimension equal to the distance between the axes of the pockets 31 less the radius of a pocket 31. The peripheral surfaces which provide the transition between the maximum and minimum radius portions are suitably formed so as to insure continuous line contact between the mating impellers 37 and 38, as shown in FIG. 4. Therefore, when assembled, the impellers 37 and 38 are always in contact with each other and each, in turn, is always in contact with the circular cylindrical surfaces of the pockets 31.

The pump casing 23 is provided with a pair of bored openings 46 whose axes coincide with the axes of the pockets 3 1. The openings 46 are adapted to receive the projecting ends of the shafts 1'7 and 19 and are of a dimension sufficient to admit the sleeve portions 44 of the hubs 39. Counterbores 47, concentric with the openings 46, are provided in the exterior face of the end wall 32 of the pump casing 23. The openings 46 and counterbores 47 form shoulder portions in .the end wall 32 against which flexible sealing rings are seated. Referring to FIG. 1, the sealing rings may take the form of annular quad-rings 48 formed to butyl rubber. An annular retaining member 49 is provided with a central opening which receives the sleeve portions 44 of the hubs 39, and the retaining members 49 each include an annular flange portion 5t having an outside diameter substantially that of the diameter of a counterbore 47 so that each retaining member 49 will be seated against a quad-ring 48. The flanges 5d of the retaining members 49 are urged against the quad-rings &8 by the action of biasing means which include washers 51 disposed about the shafts 17 and 19 and which seat against shoulders formed in the front wall 13 of the gear housing 10 by counterbores 52 concentric with the bores 14. The biasing means further includes slingers 53 also received within the counterbors 52 and disposed about the shafts 17 and i9, and each slinger 53 is provided with four circumferentially spaced, axial holes 54 which terminate in partial spherical surfaces to receive ball bearings 55 which are urged towards the spherical bottoms of the holes 54 by springs 56. The springs 56 are seated against the washers 5 1, and the slingers 53 and washers 51 are held in place by circum iferentially expandable retaining rings 57 which are re ceived within annular detents provided in the surfaces of the counterbores 52.

In assembling the rotary pump unit, the driving shaft 17 and the idler shaft 19 together with their attached gears 21 and 22 are first pre-assembled within the gear housing 10. The washers 51 and slingers 53 are mounted in the counterbores 52 and the retaining rings 57 are snapped in place to hold the Washers 51 and slingers 53 in operative position. The sealing rings 48 are placed within the connterbores 47 in the pump casing 23 against the shoulders formed with the openings 46 and the retaining members 49 are inserted in the counterbores 47 against the sealing rings 48. The pump casing 23 may now be mounted upon the front Wall 13 of the gear housing by passing the pump casing 23 over the studs 27. The dowels 25 insure that the pump casing 23 is properly seated upon the gear housing 16 so that the axes of the openings '46 and of the pockets 31 will be aligned with the axes of the shafts 17 and 19. With the pump casing 23 in place, the shafts 17 and 19' will pass through the openings -16 and will project into the pockets 31.

The impellers 37 and 38 are then placed about the projecting shafts 17 and 19, respectively. The central bores 46 of the hubs 39 are of a dimension in excess of the diameters of the projecting ends of the shafts 17 and 19 to provide a loose fit between the shafts 17 and 19 and the hubs 39 including the sleeve portions 44. This permits simple manual mounting of the impellers 37 and 38 upon the shafts 17 and 19, respectively. The reduced portions 18 and 2110f the shafts 17 and 19, respectively, are received within the complementary inserts 42 in the hubs 39 so that rotation of the shafts 17 land 19 will be transmitted into rotation of the impellers 37 and 38. When the impellers 37 and 38 are mounted on the shafts 17 and 19, respectively, the sleeve portions 44 of hubs 39 surround the shafts 17 and 19 and extend along the projecting portions of the shafts 17 and 19 through the openings 46 in the pump casing 23 to a point beyond the sealing rings 48. The sleeve portions 44 are. preferably externally tapered at their ends so that insertion of the impellers 37 and 38 along the shafts 17 and 19, respectively, and through the openings 46 can be made without damaging the sealing rings 43.

Assembly of the rotary pump unit is completed by mounting the closure plate 24 upon the pump casing 23 and the dowels 26 assist in properly aligning the closure plate 24. The closure plate 24 and the pump casing 23 are then secured to the gear housing 11? by the wing nuts 30. The lobe portions 45 of the impellers 37 and 38 are provided with a thickness which approximates the depth of the pump chamber 33 thereby formed.

When the rotary pump unit is assembled, the ball bearings 55, under the urging of the springs 56, bias the retaining members 49 against the quad-rings 48 to insure that the quad-rings 48 are firmly seated for effective sealing of the outer peripheries of the sleeve portions 44.

In operation, the drive shaft 17 is caused to rotate by a suitable power source. The identical intermeshing gears 21 and 22 will cause the idler shaft 19' to rotate at the same speed. Therefore, the impellers 37 and 38 will be caused to rotate at the same speed but in an opposite direction within the pump chamber 33. If the drive shaft 17 is rotated in a counterclockwise direction as viewed from the closure plate 24, the impeller 37 will likewise be given a counterclockwise rotation. At the same time the idler shaft 19 and consequently the impeller 38 will be caused to rotate in a clockwise direction. As the trailing edge of the single lobe of the impeller 37 rotates past the inlet port 34, material will be drawn through the inlet port 34 into the pump chamber 33 under the suction produced by the rotating impeller 37. This continues until the leading edge of the single lobe of the impeller 37 passes the inlet port 34 thereby sealing the same. As the impeller 37 continues to rotate, the leading edge of the single lobe of the impeller 37 will force the material, under pressure, toward and through the outlet port 35 until the leading edge passes the outlet port '35 at which time the trailing edge will be passing the inlet port 34 to draw more material into the pump chamber 33.

Similarly, the clockwise rotating impeller 38 alternately draws material through the inlet port 34 and forces the material through the outlet port 35. Furthermore, during the intake stroke of the impeller 37, the impeller 38 executes its output stroke and, as illustrated in FIG. 4, the mating peripheral surfaces of the impellers 37 and 38 insure that at no time is there a return passage from the outlet port 35 to the inlet port '34.

Prior to the use of the rotary pump of this invention for the handling of foodstuffs such as milk, cottage cheese, strawberries, etc., it is necessary that the parts which come in contact with the material being pumped be cleaned and sterilized. To this end, disassembly of such parts may be simply and quickly accomplished. Removal of the wing nuts 311 permits manual removal of the closure plate 24, the impellers 37 and 38, land the pump casing 23. The alternating high pressure and suction within the pump chamber 33 will cause some circulation of the material being pumped to the pump chamber side of the quad-rings 48 and, therefore, it is also necessary to clean the quad-rings 48 and the rotary pump unit of this invention is particularly suited for simple removal of the quad-rings 48. Once the pump casing 23 has been removed from the gear housing 11 the retaining members 49 are accessible and may be removed thereby permitting removal of the quad-rings 48. Thus, the following parts rnay be removed for cleaning: the closure plate 24', the impellers 3 7 and 38, the pump casing 23, the retaining members 49, and the quad-rings 48. The removal of the enumerated parts is accomplished without recourse to special tools. Once the enumerated parts have been cleaned there is no danger in the rotary pump of this invention of deleterious substances entering into the pump chamber 33 to contaminate the material being pumped.

A lubricant must be provided within the gear housing 10 for the intermeshing gears 21 and 22. The sealed bearings 15 and 16 prevent any major leakage of such lubricant from the gear housing 10. However, minor amounts of lubricants which may escape through the bearings 16 cannot find their Way into the interior of the pump chamber 33. The lubricant will flow along the projecting portions of the shafts 17 and 19 to the interior of the central bores 40 of the hubs 39. The complete isolation of the shafts 17 and 19 from the pump chamber 33 by the novel impeller construction of this invention insures that lubricants or other contaminating substances which may be present on the shafts 17 and 19 cannot find their way into the pump chamber 33. Thus, it would be necessary for all such substances to pass first around the end of the sleeve portions 44 and thence past the sealing rings 48. However, the sealing rings 48 will not permit passage of the substances therethrough. At the same time, the sealing rings 48 prevent any of the material being pumped from passing to the exterior of the pump casing 23 through the openings 46.

While the impellers 37 and 38 are shown and described as being of the single lobe type, it is not essential to the practice of this invention that the impellers be of such form. The impellers can be provided with a plurality of lobes and may have a variety of peripheral configurations. Furthermore, the lobe portions 45 may be formed integral with the hubs 39 and may be metallic.

It will be seen that the rotary pump of this invention is particularly suited for the handling of food products, and that there is no danger of contamination of the material being pumped due to the complete isolation of the shafts 17 and 17 from the pump chamber 33.

I claim:

1. A rotary pump comprising: a gear housing having front and rear walls, a pump casing provided with a pair of intersecting pockets and inlet and outlet ports communicating with said pockets, said pump casing having uninterrupted interior surfaces and including an end wall releasably secured to the front wall of said gear housing, said end wall provided with a pair of spaced openings and a pair of counterbores in its exterior surface concentric with said openings to define annular shoulder portions, a closure plate releasably secured to said pump casing to define a pump chamber with said pockets, a pair of spaced, parallel shafts journaled for rotation in said gear housing Walls and aligned with said openings, each of said shafts having a portion which projects into said pump chamber through one of said openings, intermeshing gearing on said shafts Within said gear housing, a pair of impellers removably mounted on said shafts and each within one of said pockets, each of said impellers having a central axial bore which terminates short of one face of said impeller to define an end seal wall and a sleeve portion extending from an opposite face of said impeller providing a continuation of said axial bore, said central axial bores receiving the projecting portions of said shafts and said sleeve portions extending along said shafts through said openings, an annular sealing ring within each of said counterbores about a respective sleeve portion and sealing the peripheries of said sleeve portions from said pump chamber, an annular retaining member received within each of said counterbores against said sealing rings, and biasing means anchored on the front wall of said gear housing and urging said retaining members axially against said sealing rings to seat said sealing rings against said shoulder portions.

2. A rotary pump comprising: a gear housing having front and rear walls, a pump casing provided with a pair of intersecting pockets extending inwardly from an outer surface thereof to define an end wall and inlet and outlet ports communicating with said pockets, said pump casing having uninterrupted interior surfaces and said end wall releasably secured to the front wall of said housing, said end wall provided with a pair of spaced openings and a pair of counterbores in its exterior surface concentric with said openings to define annular shoulder portions, a closure plate releasably secured to said pump casing to define a pump chamber with said pockets, a pair of spaced, parallel shafts journaled for rotation in said gear housing walls and aligned with said openings, each of said shafts having a portion which projects into said pump chamber through one of said openings, intermeshing gearing on said shafts Within said gear housing, a pair of impellers removably mounted on said shafts and each Within one of said pockets, each of said impellers having a central axial bore which terminates short of one face of the impeller to define an end seal wall and a sleeve portion extending from an opposite face of the impeller providing a continuation of said axial bore, said central axial bores receiving the projecting portions of said shafts and said sleeve portions extending along said shafts through said openings, an annular sealing ring Within each of said counterbores about a respective sleeve portion and sealing the peripheries of said sleeve portions from said pump chamber, an annular retaining member having a flange portion received within each of said counterbores against said sealing rings, and biasing means urging said retaining members axially against said sealing rings to retain said sealing rings between said shoulder portions and said retaining members, said biasing means comprising a Washer disposed about each of said shafts and restrained against rotation against the front Wall of said gear housing, and a slinger disposed about each of said shafts and restrained agianst rotation against one of said washers, each of said slingers having a plurality of circumferentially spaced axial holes, a ball bearing within each axial hole in contact with one of said retaining members, and a spring within each axial hole seated at one end on said Washer and biasing against said ball bearings.

References (Cited in the file of this patent UNITED STATES PATENTS 2,567,699 Devlin Sept. 11, 1951 2,848,952 Wakeman Aug. 26, 1958 2,858,769 Doble Nov. 4, 1958 2,878,757 Marco Mar. 24, 1959 2,976,811 Sully -e Mar. 28, 1961

Claims (1)

1. A ROTARY PUMP COMPRISING: A GEAR HOUSING HAVING FRONT AND REAR WALLS, A PUMP CASING PROVIDED WITH A PAIR OF INTERSECTING POCKETS AND INLET AND OUTLET PORTS COMMUNICATING WITH SAID POCKETS, SAID PUMP CASING HAVING UNINTERRUPTED INTERIOR SURFACES AND INCLUDING AN END WALL RELEASABLY SECURED TO THE FRONT WALL OF SAID GEAR HOUSING, SAID END WALL PROVIDED WITH A PAIR OF SPACED OPENINGS AND A PAIR OF COUNTERBORES IN ITS EXTERIOR SURFACE CONCENTRIC WITH SAID OPENINGS TO DEFINE ANNULAR SHOULDER PORTIONS, A CLOSURE PLATE RELEASABLY SECURED TO SAID PUMP CASING TO DEFINE A PUMP CHAMBER WITH SAID POCKETS, A PAIR OF SPACED, PARALLEL SHAFTS JOURNALED FOR ROTATION IN SAID GEAR HOUSING WALLS AND ALIGNED WITH SAID OPENINGS, EACH OF SAID SHAFTS HAVING A PORTION WHICH PROJECTS INTO SAID PUMP CHAMBER THROUGH ONE OF SAID OPENINGS, INTERMESHING GEARING ON SAID SHAFTS WITHIN SAID GEAR HOUSING, A PAIR OF IMPELLERS REMOVABLY MOUNTED ON SAID SHAFTS AND EACH WITHIN ONE OF SAID POCKETS, EACH OF SAID IMPELLERS HAVING A CENTRAL AXIAL BORE WHICH TERMINATES SHORT OF ONE FACE OF SAID IMPELLER TO DEFINE AN END SEAL WALL AND A SLEEVE PORTION EXTENDING FROM AN OPPOSITE FACE OF SAID IMPELLER PROVIDING A CONTINUATION OF SAID AXIAL BORE, SAID CENTRAL AXIAL BORES RECEIVING THE PROJECTING PORTIONS OF SAID SHAFTS AND SAID SLEEVE PORTIONS EXTENDING ALONG SAID SHAFTS THROUGH SAID OPENINGS, AN ANNULAR SEALING RING WITHIN EACH OF SAID COUNTERBORES ABOUT A RESPECTIVE SLEEVE PORTION AND SEALING THE PERIPHERIES OF SAID SLEEVE PORTION FROM SAID PUMP CHAMBER, AN ANNULAR RETAINING MEMBER RECEIVED WITHIN EACH OF SAID COUNTERBORES AGAINST SAID SEALING RINGS, AND BIASING MEANS ANCHORED ON THE FRONT WALL OF SAID GEAR HOUSING AND URGING SAID RETAINING MEMBERS AXIALLY AGAINST SAID SEALING RINGS TO SEAT SAID SEALING RINGS AGAINST SAID SHOULDER PORTIONS.

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