US2707441A - Rotary pump or motor - Google Patents

Description

2 Sheets-Sheet 1 Filed July l, 1952 w L n a. a @a 6 a; L J 0 u M, P. E. i l \M 3 J May 3, 1955 M. BRENNEN 2,707,441

` ROTARY PUMP 0B MOTOR Filed July l, 1952 figa 2 Sheets-Sheet 2 United States Patent O ROTARY PUMP 0R MOTOR Matthew Brennen, Youngstown, Ohio, assignor to The Commercial Shearing & Stamping Co., Youngstown, Ohio, a corporation of Ohio Application July 1, 1952, Serial No. 296,550

6 Claims. (Cl. 10B-126) This invention relates to pumps and motors with rotary impellers, and particularly to means for sealing the case around the impellers. The same assignee owns this application and the application of Thomas C. Kane, Serial No. 139,190, led January 18, 1950, for Rotary Pumps and Motors.

Conventional gear pumps and motors in the past have had diiculty developing pressures above 1,500 p. s. i. oecause of diiculties with the end plates against the gears. Recent developements in the design of the end plates and their mounting in the case have made it possible to raise the working pressures to about 3,000 p. s. i., but these developments have uncovered a further weakness in past designs, namely the tendency of the conventional sheet gaskets between the central and end casing members to fail when subjected to pressures approaching 3,000 p. s. i., particularly adjacent the bolts which fasten the case together. The failure of the gaskets results in leaks of iluid out of the case, which is generally objectionable and is particularly objectionable in food-processing plants and the like. In some cases, moreover, the gaskets blow out to such an extent as to impair the efficiency of the machine.

In accordance with my invention a sealing system is provided which enables full advantage to be taken of the higher pressures capable of being developed by recently developed forms of gear pumps and motors. I seal the joint between the central casing member and each end casing member with a loop of resilient rubberlike material which is entirely enclosed in metal and can withstand very high working pressures, such as 3,000 p. s. i. I use a pair of supplementary plates, one around the outside of the sealing means, and the other around the inside of the ceiling means, and sandwich the plates and the sealing material between one side of the central casing member and the adjacent end casing member. This construction is not only satisfactory in operation but also is readily fabricated with minimum machining and waste of material. The loop of sealing material is disposed inwardly of the connecting bolts through the case, and not only prevents leaks through the bolt holes but also makes it possible to use less bolts to hold the casing elements in sealed relation. I further improve the t of the case around the end plate against the gears by extending the inner supplementary plate across the back of the end plate and thence between the central and adjacent outer casing members, and by making the inner plate slightly thicker than the outer plate so that the pressure of the bolts drawing the casing together will be exerted primarily on the inner plate. This makes a tight metalato-metal se'al at the joint between the central casing member and the inner supplementary plate and `thus prevents a backflow from developing along said joint with consequent loss of pressure.

Other features, objects and advantages of my invention will become apparent from the following detailed description and in the accompanying drawings, in which I have shown, for purposes of illustration only, a present 2,707,441 Patented May 3, 1955 ice preferred embodiment of my invention. In the drawings:

Figure 1 is a section taken through the gear axes of a pump or motor incorporating the invention;

Figure 2 is a section on the line II-II in Figure l;

Figure 3 is a section on the line III--III in Figure l;

Figure 4 is the front face of a pressure plate in the pump or motor shown in Figure l, showing the face against the sides of the gears;

Figure 5 is a section on the line IV-lV in Figure 4, and

Figure 6 is the rear face of the pressure plate shown in Figure 4.

Referring now more particularly to the drawings, there is provided a pump or motor 10 having a pair of meshing impeller gears 11 and 12 with a pair of pressure plates 13 and 14 against their ends. The case 15 enclosing the gears and end plates includes a central casing member 16 having a bore extending around the peripheries of the' gears 11 and 12 and end plates 13 and 14. An end casing member 17 encloses the rear face of the end plate 13, and an end casing member 18 encloses the rear face of the plate 14. The central casing member 16 fits closely around the major portions of the peripheries of the gears 11 and 12 and has a pair of ports 19 and 20 on opposite sides of the gears where they mesh and unmesh to supply and receive fluid carried between the gear teeth and the central casing member 16 from one of the ports to the other, depending upon the direction of rotation of the gears (Figure 2). Eight spaced bolts 21 extend through the casing members 17, 16 and 18 to hold the case to'- gether.

The end plates 13 and 111 are identically mounted at opposite ends of the gears 11 and 12, and the details of the mounting of the plate 14 will now be described. The plate 1d is in the shape of a figure 8 (Figures 4 6). The front face 22 bears against the adjacent ends of the gears 11 and 12 and a pair of openings 23 and 2L!- slidably receive hubs 2S and 26 extending integrally from the adjacent ends of the gears 11 and 12. The rear face 27 of the plate 14 is counterbored around the openings 23 and 24 at 28 and 29 to mount one end of each of a pair of bearing shells 30 and 31, the other ends of these shells being received in recesses in the end casing member 18. Needle bearings 312 roll between the respective shells 30 and 31 and the gear hubs 25 and 26 therein, thereby journaling the adjacent ends of the gears 11 and 12 in the end plate 14. A series of channels are cut generally radially across the rear face 27 and O-ring type rubberlike sealing members 33 (Figure 6) are mounted in these channels to control fluid pres` sures on the back of the plate 14. A series of spaced lands 34 along the periphery of the plate 14 are adapted to engage the bore of the central casing member 16 at opposite ends of the plate 14 and next to the parts of the bore where the teeth of the gears 11 and 12 initiate and complete their sliding engagement with the bore. The lands 34 serve to align the plate 14 and the gears 11 and 12 in the central casing member 16, and also block flow of fluid around the peripheral edges of the plate 14. Portions of the periphery of the plate 141 between the lands 34 are relieved at 35 to allow for thermal expansion of the plate 14 in the case. With this form of end plate construction the machine is capable of developing pump pressures in the order of 3,000 p. s. i.

A loop of resilient rubberlike sealing material 36 (Figures Z and 3) extends between the casing members 16 and 18, spaced entirely outwardly of the opening through the central casing member 16 receiving the end plate 14, and inwardly of the openings through the casing members 16 and 16 for the bolts 21. The outer periphery of the sealing material 36 is conined by the inner edge of an annular' flat plate 37 which is perforated to receive bolts 21 and is entirely sandwiched between the casing members 16 and 13. The inner periphery of the sealing material 36 is confined by the outer edge of another flat plate 38, which has an outer rim sandwiched entirely around its periphery between the casing member 16 and 18, with a pair of openings therethrough slidably receiving the bearing shells 30 and 31. The loop of sealing material 36 is thus entirely confined by metal elements, and is effective to block any flow of fluid from the interior of the case between the outer plate 37 and the adjacent casing members 16 and 18.

The whole rear face of the inner plate 38 lies against the end casing member 18. The front face of plate 38 has a relatively narrow outer peripheral area against the central casing member 16. The balance of the front face area of plate 38 faces the rear face 27 of the end plate 14 and squeezes against the sealing elements 33, causing these sealing elements to elongate and press their opposite ends against the curved interior surface of the central casing member 16 and against the outer surface of one of the bearing shells 30 or 31. The sealing elements 33 are so disposed as to divide the rear face of plate 38 into different pressure areas and to oppose flow of fluid between plates 14 and 38 from the high pressure to the low pressure side of the meshing gears.

The plates 37 and 38 are preferably cut from a single sheet of mild steel, there being little waste of material Where the blanks for the respective plates are trimmed to leave a space therebetween for the sealing material 36.

The outer plate 37 is preferably ground down, after being 0 cut away from the inner plate 38, to make the outer plate 37 about 0.001 thinner than the inner plate 3S. When the bolts 21 are tightened the slightly thicker inner plate 38 is tightly squeezed around its outer rim between the casing members 16 and 18 to form a tight metal-tometal seal. This metal-to-metal seal protects the seal 36 and cooperates with the lands 34 and the seals 33 in minimizing baekow from the high pressure to the low pressure side of the meshing gears. This sealing system works equally well regardless of the direction of rotation of the gears 11 and 12, and has proven entirely satisfactory at pressures up to 3,000 p. s. i.

The end plate 13 is similarly mounted, with outer and inner plates 39 and 40, and a loop of sealing matcrial 41, corresponding identically to plates 37 and 38 and sealing material 36 at the other ends of the gears.

While I have illustrated and described a present preferred embodiment of the invention for purposes of illustration, it will be understood that the invention may be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

l. In a rotary machine of the ciass described, a rotary impeller, a case enclosing the impeller and comprising a central casing member around the periphery of the impeller and an end easing member to enclose one end of the impeller, a pair of plates lying generally in a common plane and one surrounding the other with an annular space therebetween, the portions of both plates along said annular space being sandwiched between the central and end casing members, and a loop of elastic sealing material in said annular space, said sealing material being entirely confined between the said plates and casing members and serving to prevent escape of fluid between the outer plate and the adjacent portions of the casing members.

2. In a rotary machine of the class described, a rotary impeller, a case enclosing the impeller and comprising a central casing member around the periphery of the impeller and an end casing member to enclose one end of the impeller, said casing members having adjacent opposite faces, a plate between said faces with its outer rim sandwiched between a relatively narrow section extending outwardly from the inner peripheral portion of the central casing member and the opposite portion of the face of the end casing member, and sealing means including a loop of elastic sealing material extending around the outer periphery of the plate between said faces, whereby escape of fluid between the central and the end casing members is opposed initially by a metal-to-metal seal and then by supplemental sealing means including elastic sealing material.

3. ln a rotary machine of the class described, a rotary impeller, an end plate against the impeller extending generally normal to the impeller axis, a case enclosing the impeller and end plate and comprising a central casing member around the peripheries of the impeller and end plate, an end casing member spaced from the rear face of the end plate, a pair of supplementary plates lying generally in a common plane and one surrounding the other with an annular space therebetween, the inner plate spacing the end casing member from the end plate, the portions of both plates along said annular space being sandwiched between the central and end casing members, and a loop of elastic sealing material in said annular space, said sealing material being entirely confined between the supplementary plates and casing members and serving to prevent escape of iluid between the outer supplementary plate and the adjacent portions of the casing members.

4. In a rotary machine of the class described, a rotary impeller, an end plate against the impeller extending generally normal to the impeller axis, a case enclosing the impeller and end plate and comprising a central casing member around the peripheries of the impeller and end plate, an end casing member spaced from the rear face of the end plate, a pair of supplementary plates lying generally in a common plane and one surrounding the other with an annular space therebetween the inner plate spacing the end casing member from the end plate and having a greater initial thickness than the outer plate, the. portions of both plates along said annular space being sandwiched between the central and end casing members with the inner plate more tightly compressed between the casing members than the outer plate because of the greater initial thickness of the inner plate, and

Va loop of elastic sealing material in said annular space,

said sealing material being entirely confined between the supplementary plates and casing members and serving to prevent escape of uid between the outer supplementary plate and the adjacent portions of the casing members.

5. In a rotary machine of the class described, a rotary impeller, and end plate against the impeller extending generally normal to the impeller axis, a case enclosing the impeller and end plate and comprising a central casing member around the peripheries of the impeller and end plate, an end casing member spaced from the rear face of the end plate, a pair of supplementary plates lying generally in a common plane and one surrounding the other with an annular space therebetween, the inner plate spacing the end casing member from the end plate, the portions of both plates along said annular space being sandwiched between the central and end casing members, a loop of elastic sealing material in said annular space, said sealng material being entirely conned between the supplementary plates and casing members and serving to prevent escape of uid between the outer supplementary plate and the adjacent portions of the casing members, connecting members extending through aligned openings in the casing members and the outer supplementary plate, with the said annular space and sealing material spaced radially inwardly of said openings. Y

6. ln a rotary machine of the classV described, a pair of meshing impeller gears, an end plate against the gears extending generally normal to the gear axes, a case enclosing the gears and end plate and comprising a central casing member around the peripheries of the gears and end plate, an end casing member spaced from the rear face of the end plate, said end plate having alternate portions of its periphery engaging and spaced from the central casing member and having elastic sealing members extending across its rear face, a pair of supplementary plates lying generally in a common plane and one surrounding the other with an annular space therebetween the inner plate spacing the end casing member from the end plate, the peripheral rim of the inner plate and substantially all of the outer plate being sandwiched between the central and end casing members, with the balance of the face of the inner supplementary plate against the central casing member facing the rear face of the end plate and pressing against said seals therealong, and

6 a loop of elastic sealing material in said annular space, said sealing material being entirely confined between the supplementary plates and casing members and serving to prevent escape of fluid between the outer supplementary plate and casing members.

References Cited inthe lle of this patent UNITED STATES PATENTS 695,174 Roller Mar. 11, 1902 2,420,622 Roth et al. May 13, 1947 2,527,941 Lauck et al Oct. 3l, 1950

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