US2982220A - Thrust plates for rotary pumps and motors - Google Patents

Description

May 2, 1961 'THRUST PLATES FOR ROTARY PUMPS AND MOTORS T. c. KANE 2,982,220

Filed Nov. 29, 1957 l5 I2 |e Flg .3. l4 2e 24 i 34 i? 29 30 R Z" H 34 i 33 25 i 27 INVENTOR.

THOMAS C. KANE, DECEASED BY DOLLAR SAVINGS AND TRUST COMPANY, EXECUTOR THRUST PLATES FOR ROTARY PUMPS V AND MOTORS Thomas C Kane, deceased, late of Youngstown, Ohio, by

Dollar Savings and Trust Company, executor, Youngstown, Ohio, .assignor to The Commercial Shearing and StampingCompany, a corporation of Ohio below 1500 p.s.i. because of difficulties in maintaining their end plates against the rotary pumping gears and because of the erosion of the end; plates at high pressures. Recent developments in rotary pumpand motor design have made it possible to maintain the end plates in position at pressures in the neighborhood of 3000 p.s.i. but have only accentuated the erosion problem. Rotary pumps and motors operating at these higher pressures have been consistently plagued with the problem of erosion of the thrust plates adjacent the meshing point of the gears. As the gears mesh, a certain amount of oil is squeezed out of its trapped position between the gear teeth axially ofthe gears. This fluid strikes the thrust plate at very high pressures and considerable difficulty has been experienced at the meshing point by reason of the erosion caused by this high pressure sidewise jetted oil.

The present invention overcomes this difiiculty and provides a structure which substantially eliminates the erosion at the meshing point of the gears. According to this invention, a thrust plate will have four to five times the working life of a conventional thrust plate without any detriment to the pumping action or the freedom of movement of the rotary gears.

This invention provides a thrust plate comprising a metal body in the general form of a figure 8, the body having a front face adapted to abut the gear or impeller ends, a pair of openings through the plate on opposite sides of the waist of the figure 8 adapted to receive the impeller shafts or hubs, and a thin insert of abrasionresistant alloy inlaid at the waist of the figure 8 along the meshing point of the gear teeth. Hereafter in this application when impeller shafts are mentioned, it shall for simplicity, include both impeller shafts or hubs as the case may be. Preferably, the inlaid piece of abrasion-resistant material is a thin circle of hard bronze sold under the name Ampco or similar abrasion resisting alloy and the main body of the plate is made of a leaded bronze. The leaded bronze carries the high bearing loads that occur between the thrust plate and the gears and the Ampco" disk which is inlaid in the surface of the leaded bronze takes the abrasive action of the jetting oil extruded from between the gear teeth, thus preventing erosion of the thrust plate.

While there have been set out hereinabove certain purposes, advantages and objects of the present invention, other objects, advantages and purposes will be apparent from the following description and the accompanying drawings in which,

Figure l is a partial section through a gear pump showing the thrust plate in position;

Figure 2 is a plan view of the thrust plate according to the present invention; and

Figure 3 is a section on the line IH-III of Figure 2.

Referring to the drawings, there is illustrated a rotary pump housing 10, having a pair of meshing gear impellers 11 and 12 betweena'pair of end plates 13 and 14 with neutral casing member 15. enclosing the outer peripheries of the impellers and plates. The plates 13 and 14 andcasing member 15 are enclosed between a pair of end casing members 16 and 17 and held together by .bolts 18 extendingthrough the casing members to hold said members together in tightly sealed relation. The invention will be particularly described with respect to oneof the thrust plates 14. The plate 14 is in the form ofa figure. 8 having a pair of openings 24 and 25 throughout which hubs 22 and 23 extend. These. openings are countersunk on the rear face of the plate to provide counterbores 26 and 27 fitting closely around bearing shells 19 and 20. The front face of the plate 14 is providedwith flat surfaces fitting closely against the adjacent impeller ends and with two pairs of grooves 28. which serve to carry fluid pressed between the meshing impeller teeth back to the, low pressure side of the pump regardless of the direction of rotation of the impellers. A circular insert 29 of Ampco is inlaid into a shallow well 30 in the waist 31 of the thrust plate 14 so as to lie on an axial line through the meshing point of the gear teeth. Oil ejected sidewise from the meshing gear teeth of the impellers 11 and 12 is jetted against the insert 29 and any which leaks by this plate is carried toward the grooves 28. Rubber-like seals 33 are provided in channels 34 in the rear face of the plate. Each such rubber-like seal rises above the top of the-channel in which it is placed. These seals act to form differential pressure areas on the rear face of the plate which maintain the plate in desired contact with the ends of the impeller.

The plate 13 corresponds identically with the plate 14 in construction, mounting and operation. As in the case of plate 14, the "Ampco insert 29 lies on the axis of the meshing plate between the rotary impellers 11 and 12.

The Ampco insert 29 is preferably applied by pressing into the well 30 although any suitable method of afiixing the insert in the end plates 13 and 14 may be used. For example, the insert may be cemented in place by a plastic resin cement or it may be cast into the plate, or it may be physically fixed in the plate by peening the bronze bearing metal over the Ampco disk. Other abrasion-resisting materials may be used in place of Ampco" for the disk 29. For example, cemented carbide disks or other like abrasion-resistant materials may be used. As in the case of Ampco, these disks may be applied in any satisfactory method. The insert need not be circular in shape but may take any convenient, desired form so long as it covers the area in which the gear teeth mesh and may eject oil to erode the plate. The thrust plate of the present invention provides the necessary high bearing load capacity along with resistance to the abrasive jetting action of the high pressure oil at the several points where these two characteristics are necessary.

While certain preferred forms and practices of this invention have been set out hereinabove, it will be understood that the invention may be otherwise embodied within the scope of the following claims.

What is claimed is:

1. In a rotary gear pump having a case, a pair of rotary gears in said case, the improvement comprising a unitary thrust plate for the corresponding ends of the pair of cooperating rotary gears adapted to lie between having a front face adapted to abut the impeller ends, a pair of openings extending through the body to receive the impeller shafts and an inlay of abrasion-resistant material spaced from and intermediate between said openings on the line formed between the meshing gear teeth at the intermesh point of the rotary gears andre'ceiv'ing the fluid forced axially from the gear teeth. 4

'2. In a rotary gear pump having a case, a pair of rotary gears in said case, the improvement comprising a unitary thrust plate for the corresponding ends of the pair of cooperating rotary gears adapted to lie between the case and the gear comprising a leaded bronze body in the form of a figure 8, said body having a front face adapted to abut the impeller ends, a pair of openings extending through the body to receive the impeller shafts and 'an inlay of abrasion-resistant material flush with said face, spaced from and between said openings and on the axial line formed between the meshing gear teeth at the intermesh point of the rotary gears, said inlay receiving the fiuid forced axially from the gear teeth.

3. In a rotary gear pump having a case, and a pair of rotary gears thereon, a thrust plate as claimed in claim 2 wherein the inlay is a disc of hard bronze.

4. In a rotary gear pump having a case, and a pair of rotary gears thereon, a thrust plate as claimed in claim 3 wherein the disc is silver soldered into a well in the "plate.

5. In a rotary gear pump having a case, and a pair of rotary gears thereon, a thrust plate as claimed in claim 3 wherein the inlay disc is pressed into a shallow well in the plat in frictional engagement therewith.

6. In a rotary gear pump having a case, and a pair of rotary gears thereon, a thrust plate as claimed in claim 3 wherein the inlay disc is cemented into a shallow well in the plate.

7. In a rotary gear ump having a case, and a pair of rotary gears thereon, a thrust plate as claimed in claim 3 wherein the plate is cast about the inlay disc.

References Cited in the file of this patent UNITED STATES PATENTS 621,280 Pitt Mar. 14, 1899 2,395,824 Herman -e Mar. 5, 1946 2,412,698 Van der Horst Dec. 17, 1946 2,534,406 Bramberry Dec. 19, 1950 2,611,323 Digney Sept. 23, 1-952 2,619,040 Maisch Nov. 25, 1952 2,662,483 Smith et al. Dec. 15, 1953 2,707,441 Drennen May 3, 1955 2,714,856 Kane Aug. 9, 1955 2,742,862 Banker Apr. 24, 1956 FOREIGN PATENTS 724,353 Great Britain Feb. 1 6, 788,669 Great Britain Jan. 8, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF. CORRECTIQN Patent No, 2 982320" 1 May 2 1961 I Thomas C Kane It is hereby certified that error appears in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below,- A 7 Column l line 20 after "'wel l k nown insert a period; column 2 llne 16 for throughout? read through e;

column 4L line 4 for plat read plate e Signeiiland'sealed this 19th fday iof September 1961o (SEAL) Attest:

ERNEST W. SWIDER A DAVID L. LADD Attesting Officer I "Commissioner of Patents USCOMM-DC

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