US2903235A

US2903235A - Valves

Info

Publication number: US2903235A
Authority: US
Inventors: Rodgers Otis Ned; Wallace F Olson
Original assignee: American Iron & Machine Works
Current assignee: American Iron & Machine Works; American Iron & Machine Works Company Inc
Priority date: 1954-06-21
Filing date: 1954-06-21
Publication date: 1959-09-08
Anticipated expiration: 1976-09-08

Description

Sept. 8, 1959 o. N. RODGERS ET AL 2,

VALVES Filed June 21, 1954 s Sheets-Sheet 1 029$ /Ve0 Ron yen:

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VALVES Filed June 21, 1954 s Sheets-Sheet 2 0kg; Ned Rod 79A;

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IN VEN T0 A TTO/gA Ey Sept. 8, 1959 o. N. RODGERS ET AL 2,903,235

VALVES Filed June 21, 1954 3 Sheets-Sheet 3 Wa/ e O/J0/7 ENTORS BY m United States Patent O VALVES Otis Ned Rodgers and Wallace F. Olson, Oklahoma City, Okla, assignors, by rnesne assignments, to American Iron & Machine Works Company, inc, Oklahoma City, Okla, a corporation of Delaware Application June 21, 1954, Serial No. 438,122

4 Claims. (Cl. 251-332) This invention pertains to valves and more particularly to valves incorporating an element of low elastic modulus material compared to steel and other hard metals, e.g. a rubber-like flowable material such as neoprene or hycar, for sealing between a valve seat and valve closure. The seat and closure will usually be made of steel or other hard material, though in some cases the seat or closure or both may incorporate softer materials supported by other harder and stronger material.

The invention is particularly suited for use in connection with valves for slush pumps used to circulate fluid through an earth hole in well drilling. Such pumps operate at high pressure, e.g. several thousand pounds per square inch and the fluids pumped are highly abrasive, usually carrying a considerable amount of suspended sand. To meet such conditions a type of valve now in common use in slush pumps comprises a steel base member providing a means for closing at least most of the opening controlled by the valve, a sealing element carried by the base member for sealing between the base memher and valve seat, and a cap member over the sealing element, the flow of fluid controlled by the valve being in the direction generally from the cap member to the base member. The sealing element engages the base member and valve seat on the same sides with respect to the direction of fluid flow, which in the usual case is the upstream side of each. The cap member serves to retain the sealing element in position, especially when the valve is not in the fully closed position. The cap and base members, together with the valve seat, largely confine the sealing element so that it will not be deformed beyond its yield point when exposed to full pressure differential in the closed position of the valve.

The sealing element is made of low elastic modulus material so that it will, under pressure when the valve is closed, flow into all the small irregularities in the surfaces of the valve seat and base member in contact therewith to seal therewith and hence form a seal therebetween. The sealing element will also fill the irregularities of the cap member and seal therewith, thereby forming a seal bridging the cap member and valve seat. In some cases the base member and cap member may be integral. A general statement of the function of the sealing element is thus to seal with and between the valve seat and the valve closure.

The sealing element will not only flow to fill the irregularities in the valve closure and seat but it will also flow into the crevice at the juncture of the valve closure and seat, e.g. between the base member and valve seat. This crevice will be larger than the surface irregularities of the valve seat and closure, especially after the valve is worn, so that the strain or deformation of the material required to fill the crevice will be much larger. The stress on this bridging portion will be proportionately higher and may be close to the elastic limit.

deformation in valve closed position, so that every time the valve moves between open and closed position there is a stress reversal.

The bridging portion of the sealing element in many types of valves will be at a place where the direction of the surface of the element changes, sometimes sharply. Often the valve closure element, e.g. the base member thereof, will have a sharp corner adjacent the bridging portion of the sealing element. This not only provides a sharp transition fiom supported to unsupported condi tion of the sealing element but may actually form a knife edge tending to cut it.

For the above outlined reasons and perhaps others, it has been found that the bridging portion of the sealing element of a slush pump valve is often the first point of failure thereof after a period of use. It is the principal object of this invention to eliminate or retard such failure so as to prolong the life or" the sealing element.

Other objects and advantages of the invention will appear from the following description of a preferred embodiment of the invention and several modifications thereof, reference being made to the accompanying drawings in which Figure l is a vertical section through a slush pump valve and seat showing a preferred embodiment of the invention;

Figure 2 is a bottom view, partly in section, of the sealing element shown in Figure 1;

Figure 3 is a plan view of the clamp shown in Figure 1;

Figures 4-14 are vertical sections through portions of valves and seats similar to that of Figure 1 and showing modifications thereof.

Referring now to Figure 1 there is shown a portion of a pump body 10 having a removable and replaceable valve seat ring 11 inserted in an opening therein. The valve seat ring has a conical surface 12 forming a seat and a plurality of webs 13 forming a spider supporting a lower valve stem guide bearing 14.

The opening through the valve seat ring is shown as closed by a valve comprising a stem having a lower portion 20 provided with a plurality of rubberlike wear rings 21 thereon slidably disposed in bearing 14, and an upper portion 22. A disc or flange 23 integral with the valve stem has a plane bottom surface 24 spaced slightly above the webs 13 and bearing 14, a conical outer peripheral edge 25 adapted to seat on surface 12 of the seat ring, and a conical upper surface 26 interrupted by a square cross-section annular bead 2'7. Flange 23 is the base member of the valve closure.

On top of flange 23 is disposed a sealing element 3i which may be made of natural or synthetic rubber and may be suitably modified with fillers. For example the sealing element may be made of neoprene or hycar and desirably has a hardness in the range of to 75 durometer, preferably durometer.

The lower surface 31 of the sealing element is conical to engage surface 26 of the flange 23, and have a square section annular channel 32 to receive bead 27.

The sealing element 31 is a ring having a central cylindrical opening 33 to slide over an enlarged portion 34 of the valve stem. The upper surface 35 of the sealing element 30 is plane and the thickness of the element is such that slight axial compression is required to bring surface 35 even with plane shoulder 36 on the valve stem. This compression is achieved by a cap member in the form of a plate or removable flange 37 held in place by a U shaped clamp 38 slipped under a downwardly facing shoulder 39 on the valve stem and retained by a pin 40 (see Figure 3).

Sealing element 30 has a flaring peripheral surface 50 adapted to contact surface 12 of the valve seat ring. When unstressed, surface 50 is conical and forms a continuous extension of surface 25 of the flange 23. When the sealing element is compressed by plate 37 the surface 50 bulges out slightly as shown.

Sealing element 36 has a conical peripheral surface 51 flaring opposite to surface 50 joining

surfaces

50 and 35, the juncture between

surfaces

50 and 51 being rounded asshown at 52, portion 52 extending slightly out over the upper plane surfaces 53 of the seat ring.

Sealing element 3t has incorporated therein at the bridging portion 60 a reinforcement means 61. This reintorcement means increases the tensile strength, the elastic modulus and the surface hardness at this point. Although it must be close to the surface to effect these results, it must be disposed beneath the surface, as shown, in order not to impair the sealing qualities of the element.

Preferably the reinforcement means 60 comprises an element such as at vulcanized into place. Element 61 may be in the form of a plurality of filaments parallel or random stacked, or in the form of a cloth made of individual filaments felted or woven or otherwise integrated, or in the form of a continuous sheet, and may be made of any of a variety of materials such as cotton, linen, nylon, fibre glass, steel, copper, bronze. Canvass is a suitable material as shown best in the broken away section in Figure 2.. The surfaces of the component sheets of the reinforcing means, whether they be canvass, metal, or other material, extend parallel to the adjacent surfaces of the sealing element where it bridges between valve seat and closure.

As shown in Figure l, the reinforcing means preferably not only extends over the bridging portion 60 of the seating element 23 but extends over the portion that engages head 27. This reinforces the sealing element at its point of engagement with head 27 where it is also subject to severe stresses, the head 27 and channel 32 interlocking and preventing the sealing element from pulling away from enlargement or hub 34 under fluid pressure. The reverse bends of the reinforcement as it passes around channel 312 and head 27 also lock it in place in the sealing element preventing it from pulling loose.

Referring now to Figures 4 through 14, in each figure the valve seat ring base member, cap member, sealing element, and reinforcing means are given the same numbers as the like parts in the Figure 1 embodiment, from which their construction will be readily understood.

It is to be noted that it is not desirable to reinforce the sealing element throughout, for this would increase its hardness and strength and resistance to cold flow under pressure to such an extent that it would no longer perform its scaling function. The sealing element as a whole should have the desirable flow characteristics of natural or synthetic rubber unhampered by any reinforcing means.

While a preferred embodiment of the invention and a number of modifications thereof have been shown and described, many modifications thereof can be made by one skilled in the art without departing from the spirit of the invention, and it is intended to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

We claim:

1. A valve sealing element adapted to be mounted with its axis in a vertical plane comprising a ring made of vulcanized rubber compound, the bottom face of the ring being dished inwardly providing a base plate engaging portion, the lower outer periphery of the ring flaring upwardly providing a seat engaging portion, said ring including fabric reinforcement means just beneath its surface at the juncture of said seat engaging and base plate engaging portions, the hardness of said ring being in the range of 65 to 75 durometer except at said fabric reinforced juncture where it exceeds 75 durometer in hardness, said reinforcing means comprising canvass sheets disposed with their surfaces geometrically similar to the outer surfaces of the ring adjacent thereto, the edges of the canvass lying beneath the outer surface of the ring.

2. A valve device including a metal seat with an opening therein and a subassembly comprising a valve closure means large enough to close said opening, the outer periphery of said closure means providing a continuous rigid metal surface whose edge is contiguous with said metal seat when the valve member is in closed position, and a sealing element of rubber-like material disposed to seal with said closure means and seat, sealing with both said seat and closure means on the same sides thereof with respect to flow through said opening, and to bridge the juncture between said seat and said outer periphery of said closure means the portion of said sealing element that seals with said seat extending beyond, said outer periphery of said closure means, said sealing element having reinforcing means at the bridging portion thereof to decrease the elastic modulus and increase the strength of the sealing element at that portion, said reinforcing means comprising sheet material embedded in said sealing element close to but beneath the surface thereof that is adjacent said outer periphery of said closure means and said seat when said subassembly is in closed position, the surfaces of said sheet material being disposed parallel to the surface of said sealing element adjacent said bridging portion and the portion therebeyond where said sealing element engages the seat when the valve subassembly is in closed position, the outer edges .of said sheet material terminating beneath the surface of said resilient material, the reinforcing means being free from exposure to frizzing and frazzling at the seating portion of the sealing element, the bond between said reinforcing means and the remainder of the sealing element being subjected primarily to compression and transverse bending moment when loaded and free of direct pulling apart stresses, and the entire surface of the seating portion of the sealing element being free to flow into sealing engagement with said seat.

3. A valve including a body having an opening therethrough providing :an inlet and outlet and having a valve seat therearound and a valve head comprising a .valve closure including a base member and a cap member, the outer periphery of said base member providing a continuous rigid metal surface whose edge is contiguous to said valve seat, and a sealing element disposed between said base member and cap member adapted to seal with said closure and said seat on the same side of said seat and base member as said cap member and to bridge between said seat and base member, said periphery of the base member being conical flaring toward said cap member and the upper surface of said base member being conical flaring away from said cap member, the periphery of said sealing element being generally conical and forming 'a continuation of said conical periphery of the base member, the lower surface of the sealing element being conical correlative to said upper conical surface of said base member, said valve seat having an inner periphery that is conical flaring in the same direction as the peripheries of said base member and sealing .element, said sealing element comprising a ring of rubber-like material havinga fabric reinforcing means just below the surface at the portion thereof at the juncture of said conical surfaces thereof opposite the juncture of said conical surfaces of said base member, said reinforcing means being disposed and adapted to resist deformation andcold flow under pressure of said bridging portion into the space between closure andseat, said reinforcing means comprising sheet material whose surfaces lie parallel to the adjacent conical surfaces of said sealing element on both sides of said juncture thereof, the peripheral outermost portions of said sheet material terminating within said sealing element beneath the surface thereof the rubberlike material of the sealing element covering the fabric ends to prevent; 'whiskering thereof and the fibres of the reinforcing material lying just beneath the surface of the sealing element parallel to the surface resisting flow thereof into the crevice at the juncture of the valve seat and said base portion.

4. A valve subassembly comprising a valve closure means having the general shape of a disc having two faces facing generally in opposite directions relative to the disc axis, the outer periphery of said closure means disc providing a continuous rigid metal surface, and a sealing element of rubber-like material having a portion thereof with a surface disposed on one of said faces of said closure disc to seal therewith and having a portion extending beyond said outer periphery of the disc forming a continuous resilient sealing surface contiguous with said outer peripheral surface of the closure disc, said sealing surface of said sealing element and the surface of the first said portion of said sealing element that seals with said one face of the disc both facing generally in the same direction relative to said disc axis, the portion of said sealing element adjacent the juncture of said peripheral surface and the overhanging portion of said sealing element forming a bridge between said overhanging portion of the sealing element and said portion thereof disposed on said disc, said sealing element having reinforcing means at the bridging portion thereof to decrease the elastic modulus and increase the strength of the sealing element at that portion, said reinforcing means comprising sheet material embedded in said sealing element close to but beneath the surface thereof that is adjacent said outer periphery of said closure means disc and said sealing surface of said sealing element, the surf-ace of said sheet material being disposed parallel to the surface of said sealing element adjacent said bridging portion and said portion therebeyond that forms said sealing surface, the outer edges of said sheet material terminating beneath the surface of said resilient material, the reinforcing means being free from exposure to frizzing and frazzling at said sealing surface of the sealing element, the bond between said reinforcing means and the remainder of the sealing element being subjected primarily to compression and transverse bending moment but free of direct pulling apart stresses when subject to fluid pressure parallel to said axis and said entire sealing surface of said overhanging portion of the sealing element being free to flow under said pressure.

References Cited in the file of this patent UNITED STATES PATENTS 1,352,735 Egerton Sept. 14, 1920 1,781,129 Sexauer Nov. 1 1, 1930 1,890,247 Dieterich Dec. 6, 1932 2,093,662 Steirly Sept. 21, 1937 2,457,492 Raybould Dec. 28, 1948 2,495,880 Volpin Jan. 31, 1950 2,605,080 Rea July 29, 1952 2,718,373 Henry Sept. 20,, 1955 2,745,631 Shellman May 15, 1956