US2061480A

US2061480A - Valve and valve assembly

Info

Publication number: US2061480A
Authority: US
Inventors: Reginald J S Pigott
Original assignee: Gulf Research and Development Co
Current assignee: Gulf Research and Development Co
Priority date: 1930-12-05
Filing date: 1930-12-05
Publication date: 1936-11-17
Anticipated expiration: 1953-11-17

Description

Patented Nov. 17, 936

PATENT OFFICE VALVE AND VALVE ASSEMBLY Reginald J. S. Pigott, Pittsburgh, Pa., as'signor, by

mesne assignments. to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Application December 5, 1930, Serial No. 500,359 8Claims. ((1251-128) This invention relates to valves and valve assemblies, particularly those of the check or automatic type. The invention is especially concerned with valve assemblies and their relationships in combination in pumps such, for example, as deep well oil pumps.

The invention will be considered and disclosed in connection with well pumps but, as will be readily observed as. the description proceeds, it has many phases and features which are capable of much broader application.

Most commercial valve assemblies of the present day are designed with sharp edges or other restrictions in the path of fluid flow, with little or no attention given to proper stream-lining of the passages and surfaces with which the fluid comes into contact. The formation of vena contracta in this manner cuts down the capacity for flow and increases the drop in pressure necessary to cause any given flow. When valve assemblies of this nature are utilized in a pump they materially reduce its efficiency and, in the case of an oil well pump, they cause frothing and evolution of gas during the suction stroke with the results that what is known as gas locking may occur and the volumetric capacity is decreased.

Accordingly, it is one of the major objects of the present invention to reduce or substantially eliminate the defects and disadvantages pointed out in the preceding paragraph. More specifically stated, some of the objects of my invention are to streamline the surfaces of the passages through a valve assembly and to' so proportion the various cross sectional areas of said passages that a Venturi effect is obtainedupon the fluid flow through the assembly; to produce gentle changes in the cross sectional areas of flow and thus permit the flow to be substantially unrestricted; and to so design the elements of the assembly that, in the direction of flow, no cross sectional area is substantially less than the preceding one. Another specific object consists, in a combination involving a valve having a stem working ina guide, of so designing the valve head and guide that they form, in effect, a single smooth body when the valve is open.

Another undesirable characteristic of most of the present day valve assemblies of the automatically operated type is that thevalves are given too great a rise; 1. e., the distance between closed and fully open positions is made greater than is necessary for the passage of the fluid which the valve-controlled line is capable of conveying. In most instances the valve rise is equal to from 50% to 100% of the diameter of the ball (where the valve is of the ball type). As a consequence, too much time is necessary for the valve to move from its open to' its seated position, and-in a pump this results in a decreased efiiciency of the latter. Moreover the valve, in

' moving through a long stroke, may become so accelerated as to strike its seat with great force, to the damage of the valve or seat, or both.

Accordingly, itis another major object of the present invention to provide a valve assembly wherein the permitted distance of valve movement relative to its seat is at a minimum, 1. e., wherein the valve rise is limited to give sub? stantially the same passage area between the valve and its seat as the area of the throat or opening in the valve seat through which the flow takes place. This limitation of valve movement will depend upon the shape 'of the valve proper and the angle of the valve seat. For example, in a check valve assembly of the ball type, if the angle of the seat, relative to the general plane of the seat, is between 45 and 55, the rising movement need not be greater than from 25% to 30% of the diameter of the ball, In this way the valve action is not delayed, and pounding of the valve on its seat is materially reduced. The streamlining and the proportioning of cross sectional areas, already discussed, are

features which cooperate to permit the valve rise to be shortened to a great extent in the manner just outlined.

Practically all oil wells produce some sand, particles of which are carried upwardly with the oil that passes through the well pump. In conventional valving arrangements of the types hitherto employed, the sand particles tend to settle out and deposit in the pump whenever, the direction of flow is changed or the flow is restricted by the sharp edges. -This is highly undesirable, since any depositions or accumulations of sand cause destructive abrasion of the valve assemblies, packings and other parts, with consequent loss in pump efilciency and necessity for frequent repairs. I

Accordingly, it is a further major object of the present invention to provide a valve assembly which will not be subject to excessive abrasion by sand and which will not cause the deposition and accumulation of sand particles brought to it by the pumped oil.

Other objects of this invention will appear from the following detailed disclosure and the appended claims, when studied in connection with the accompanying drawing, wherein:

Figure 1 is a vertical sectional view taken longitudinally through a portion of a deep well pump assembly for the purpose of illustrating one adaptation of the present invention.

Figure 2 is a view similar to Figure 1 and showing a modified form of valve assembly.

Figure 3 represents a side elevational view of one of the valves of Figure 2, removed from its assembly and enlarged.

Figure 4 is a top plan view of the valve of Figure 3.

Figure 5 represents a cross section taken on the horizontal plane of the line 5-5 in Figure 2, and looking upward in the direction of the indicating arrows.

With continued reference to the drawing, wherein like numerals are employed to designate like parts, and with particular reference for the moment to Figure 1, numeral 6 indicates -the outer stationary casing of a liner type deep well pump, within which casing there is secured a liner in the form of a working barrel 1. This general type of pump is conventional in the art.

The barrel 1 has a cylinder bore containing an operating plunger 9 designed to reciprocate therein for the purpose of pumping oil or the like. The plunger carries a set of alternately contracting and expanding rings I0 and I2 respectively, forming a packing for sealing the outer surface of the plunger with respect to the barrel bore. The plunger bore 8 is enlarged at the lower end of the plunger to form a casing I3 for a traveling valve assembly now tobe described.

A valve cage I4 is inserted in the casing l3 to fit snugly therein with its upper end abutting an annular shoulder l5 formed by the enlargement of the plunger bore. The cage is open-ended axially of the bore 8, its lower end comprising a set of spaced fingers l6 ending in another ring l M formed solid therewith and abutted by a valve seat member I l. The member i1 is hollow axially of the bore and is screwed into the bottom of the casing [3 to complete the lower end of the plunger. On its upper surface the member I! has an inclined circular seat.l8 for the reception of a ball valve l9. The latter is of such size that it fits freely, yet without excessive play, within the several fingers l6 which serve to guide it vertically during operation. A narrow horizontal bridge 20 is formed integral with the cage l4 to extend through the bore to provide a stop for limiting the vertical rise of the ball from its seat.

It will be observed that the bridge 20 is so disposed that its distance from the top of the ball l9 when the valve is closed is materially less than the radius of the ball. In the particular illustration this distance is about 30% of the ball diameter, and the seat I8 is inclined to the horizontal at an angle of approximately With such an arrangement, when the ball is fully up in contact with the bridge, the area of flow between the ball and its seat is approximately equal to the horizontal throat area of the valve seat. Otherwise stated, the annular opening between the ball and its seat is sufficient to take care of the total quantity of fluid permitted to flow through the seat opening, and this in spite of the relatively small valve rise. This arrangement has the advantages that the ball may return to its seat, quickly and without destructive hammering. Most commercial v'alves have a much higher lift than this, varying from 50% to 100% of the balldiameter, as a result of which there is a delayed seating to reduce the volumetric elficiency, and

restrictions liable to form a vena contracta, all

edges being rounded and smooth as, for example, at 22 on the lower side of the seat member I1 and at the diffuser portion 23 where the fluid exits from the valve cage into the bore 8. Such round ing and smoothing would not, alone, accomplish the desired results. The assembly is further designed for very gentle and gradual changes of section throughout the passage of flow and to create, over all, a Venturi tube effect. The effective flow areas, (1) of the throat in the seat, (2) between the open valve and its seat, (3) up the sides of the valve cage, and (4) the bore 8 adjacent the cage, are made as nearly equal as possible. In no case is any of these effective areas materially less, in the direction of flow, than the preceding one. This designing and proportioning not only directly increases the pump efficiency, but also aids in an indirect increase of efilciency by permitting the greatly reduced valve rise or lift; previously emphasized.

The valve assembly just described constitutes the traveling valve of the pump. A standing valveassembly is mounted at the lower end of the barrel 1 for pumping cooperation with the traveling valve. A sleeve section 24 is screwed into the end of the barrel and has a cylindrical section l3 forming a valve casing. A valve cage l4, having guiding fingers l6, lower ring I I4 and a stop bridge 20', is inserted upwardly into the casing l3. A seat ring l'l' abuts the ring H4 and is held in position by its engagement with an anchoring sleeve 25 that is screwed into the lower end of the casing III. A ball valve l9 rests upon a seat l8 formed on the ring 11'.

It will be observed. that, except for relative sizes and modes of functioning, the traveling and standing valve assemblies are substantially identical in construction. The latter like the former, is designed for minimum ball rise and is rounded and otherwise shaped to impose an inappreciable restriction upon the fluid flow. The streamlining and proportioning of the passages of the valve assemblies minimize the pressure drop therethrough, and reduce the amount of gas evolved from the oil on the suction stroke, thus decreasing gas locking and increasing the volumetric efficiency of the pump. Moreover, there is no tendency for any sand present to settle from the liquid, and very little surface area upon which sand may be deposited.

-In Figures 2 to 5 there is illustrated a modified form of valve assembly. A working barrel 1 contains a plunger 9 terminating in avalve casing l3, and at its lower end supports a special sleeve section 24' which contains a standing valve assembly. The valve assemblies of Figure 2 differ in several respects from those of Figure l, but mainly in that poppet valves are provided which are positively guided for accurate seating and vertical movement.

In the traveling valve assembly of Figure 2 there is a streamlining cage having a ring 26 fitted up against the plunger shoulder l5, which ring has a curved diffusive surface 21 for gradually and gently merging the cylindrical surfaces of the bore 8 and the casing 13. A valve guide 28, having several integral and radial positioning fins 29, is formed solid with ring 26, and with lower ring Ma, the upper ring 26 abutting shoulder 7 I in plunger 9 and the outer edges of the fins engaging the inner cylindrical surface of the casing l3. A valve'head 30 has a-stem 32 vertically slidable'in the guide 28, and a seating ring I! is then screwed into the lower'end of the casing l3 to provide a seat 36 for the valve head, and abutting the ring Ma, thus maintaining the valve guide 28 in fixed position relative to the plunger. I

The upper end of the guide 28 is closed to present a; dome shaped exterior surface 33 that cooperates with the ring surface 21 to form a smooth streamlined passage. designed to receive fluid from the several vertical passageways 35 formed by the fins 29. The passes 35 in turn receive fluid, when the valve is in open position during the illustrated down-stroke of the plunger, from the throat of the seating ring I! by way of a seat 36 formed on the upper surface of the latter. The valve head 30 is substantially cone-shaped, and the seat 36 is correspondingly shaped to receive the head in uniform surface contact when the latter is down.

The valve stem is joined to the head by a frustro-conical portion 31, and the lower end of the guide 28 is cut, as at 39, to receive this portion in full surface contact when the valve is in maximum open position. The stem has a set of longitudinal flutes 38 extending from end to end and across the surface 31 to terminate at the largest portion of the head 30. These flutes are for the purpose of admitting and releasing oil from behind the upper end of the stem and thus permitting the valve to reciprocate freely during operation. The flutes may, of course, be cut in the guide instead of upon the stem. 3

It will be observed that the valve head 30 in all positions forms, with the seat 36, a passageway having all contours smoothlyrounded and so shaped that the flow area is of uniform character, taking place between constantly parallel surfaces. The changes of direction of flow are gradual and there are no abrupt material changes in effective cross sectional flow area through the assembly, as a result of which the pressure drop is small and the tendency toward abrasion by sand particles is greatly reduced. When fully opened, the valve head forms a smooth continuous surface, like that of a single body, with the guide 28, thus further decreasing the resistance.

The design is such that there is no deposition of sand on any part of the valve, guide or seat. When the valve is open it seats upwardly on a beveled surface with the sole exception of the several flutes. As there is no flow in the flutes at this time, and'hence no tendency to' drive sand up through them, no sand particles can gain access to the interior of the guide 23. During opening movement of the valve, when the plunger is on its down stroke, oil will be gushing out of the flutes to prevent the entrance of sand thereinto, and oil will be flowing upwardly through the assembly at too great a velocity for any sand to settle out. At the end of the down stroke, the vvalve will drop to its seat and the body of oil above the valve will become momentarily stationary. It is at this time only that any sand in suspension will tend to settle out, but the described design is such that there can be no harmful deposition. Some of the settling sand will accumulate on the inclined surface 31, and its tendency to roll off this surface will prevent it from entering theflutes 38. The remainder will lodge around the valve head and seat. Then, when the valve reopens on the succeeding downward stroke of the plunger, the oil forced down through the flutes from within the guide will wash the sand off the surface 31. The main flow of oil gushing upward through the valve seat will, of course, displace any. sand lodged around the seat. The result is, therefore, a valve assembly which tends to free itself of abrasive matter and which, having an inverted stem and guide, protects its guide from sand entry.

In this design, as in that of Figure 1, the valves are given a minimum lift in order to prevent de-' layed closing and destructive hammering. The passes 35 are designed to take the full flow from the opened valve, and the circular passage formed by the conical surfaces of the valve head and seat when the valve is fully open is such that it can just handle the maximum flow through the throat of the seating ring. In this instance, however, the relationship can not be defined with reference to a ball diameter. It might, however, be said in respect to both the forms of Figures 1 and 2 that the shortest distancebetween the valve and its seat is within the approximate range of from 25% to 45% of the diameter of the seat, depending on the angle at which the seat is cut.

The standing valve assembly of Figure 2, al-

though possessing common characteristics with.

the traveling valve, differs in several respects. A streamlining surface 21' is formed directly upon the interior of the sleeve 24' adjacent the dome of the guide 28. The fins 35 of the guide are formed integral with the valve casing l3. The seat ring 11, instead of abutting the fins, is thrust against an annular shoulder 40, formed as an integral part of the casing l3, by the anchoring section 25 screwed into the lower end of the casing. If desired, this valve assembly may be formed generally like the corresponding assembly of Figure l, i. e., with a cage and a ring corresponding to ring H4.

The pump of Figure 1 is shown in idle position, and that of Figure 2 with the plunger moving just at the end of its down stroke. Traveling and standing valves in pumps are so well known that it is'deemed unnecessary here to describe a cycle of pump operation.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed is:

1. In a valve assembly particularly adapted for oil well pumps wherein sand is present in the fluid and of the type wherein the valve is normally either completely open or completely closed, means providing a passageway of non-uniform cross sectional area; a valve seat member disposed adjacent a portion of said passageway and provided with a seat of less diameter than that of said portion; valve guiding and stop means disposed in a second portion of said passageway munication with said second portion and of less diameter than the latter; said seat member, valve and guiding and stop means being so streamlined and proportioned, and said stop means being so positioned relative to the seat that a Venturi flow effect is produced through the complete valve assembly, with substantially the same pressure in both the first and third portions of the passageway.

2. In a valve assembly for controlling fluid flow, a valve comprising a stem and a head of relatively larger diameter than said stem; a valve guide arrange to guide said stem and having an open end shaped to receive a portion of said valve head in surface engagement therewith; flutes formed between said guide and said valve stem to direct fluid upon said valve head for washing thereof upon relative movement between said guide and valve stem; and flutes formed upon said valve head connecting with said first-mentioned flutes.

3. In a valve assembly, in combination, means forming a stream-lined passageway for fluid flow; a valve guide closed at one end and stationarily arranged longitudinally of said passageway with its open end pointing in a direction opposite to that of the fluid flow; a valve seat member mounted in said passageway adjacent the open end of said guide; and a valve having a convex head designed. to close upon said seat member and a stem slidably projecting into said guide, said valve head and guide cooperating when the valve is open to form a smoothly curved unit so related to the seat and passageway as to produce a Venturi flow through the assembly; said valve head having an upper convex portion; said guide being of dome formation with its open end shaped to receive said convex portion of the valve head in surface engagement therewith when the valve is open; and flutes being formed between the guide and the valve to permit free reciprocation of the latter.

4. In a valve assembly for controlling the flow of relatively viscous fluids such as oil or the like containing quantities of sand and dirt, in combination, a passageway for fluid flow; a valve guide disposed longitudinally of said passageway, one end thereof being closed and one end open, the latter end opening in a direction opposite to that of the fluid flow; a valve seat in said passageway adjacent the open end of said valve guide; a valve having a stem engaging said guide and a head having a rear face tapered toward said guide to facilitate the discharge of and to prevent the collection of sand and dirt between said valve and said guide as said valve goes to open position, the diameters of said stem and the interior of said guide being equal to at least onehalf the diameter of saidvalve head whereby on moving to open position, a substantial quantity of fluid is flushed across the rear face of said valve head to remove sand and dirt therefrom.

5. In a valve assembly for controlling the flow of relatively viscous fluids such as oil or the like containing quantities of sand and dirt, in combination, a passageway for fluid flow; a streamlined valve guide disposed longitudinally of said passageway having an end opening in a direction opposite to that of the fluid flow; a valve seat in said passageway adjacent said open end; a valve having a stem engaging said guide and a head having a rear face of convex shape arranged to engage the open face of said valve guide when in open position and a front face of convex shape whereby said valve guide and head in open position form a unit offering a minimum of resistance to fluid flow through said assembly, said stem being of a diameter of at least one-half the diameter of said head.

6. A valve assembly comprising a casing such as the working barrel of an oil well pump, an inverted cup-shaped valve guide element disposed substantially axially of the casing and designed to permit any upwardly flowing oil to pass therearound, said guide element being completely closed at its upper end, a, valve seat member mounted below the open end of said guide element in spaced relation thereto, and a valve comprising a head having a convex surface designed to close upon said seat member'and having a stem projecting upwardly into said guide element for vertical reciprocation therein, there I being oil venting openings leading downwardly between said guide element and said head, said openings terminating adjacent said head whereby on the up stroke of the valve, any oil entrapped in the guide element will gush upon and wash the upper surface of said head.

'7. In a valve assembly for controlling the flow of relatively viscous fluids such as oil or the like.

containing quantities of sand and dirt, in combination, a passageway for fluid flow; a valve guide disposed longitudinally of said passageway having an end open in a direction opposite to that of the fluid flow; a valve seat in said passageway adjacent said open end; a valve having a stem engaging said guide and a head having a rear face arranged to engage said open end when in open position and shaped to form a convex surface so as to facilitate the removal of sand and dirt therefrom as said valve moves to open position, the relative diameters of said valve head and guide being such that they cooperate when said valve is open to form an obstruction so related to said seat and passageway as to produce a Venturi flow through the assembly, the rear face of said valve head being tapered toward said guide; said guide having a circular seat substantially parallel to said tapered face and designed for surface contact therewith.

8. In a valve assembly for controlling the flow of relatively viscous fluids such as oil or the like containing quantities of sand and dirt, in combination, a passageway for fluid flow; a valve guide disposed longitudinally of said passageway having an end open in a direction opposite to that of the fluid flow; a valve seat in said passageway adjacent said open end; a valve having a stem engaging said guide and a head having a rear face arranged to engage said open end when in open position and shaped to form a convex surface so as to-facilitate the removal of sand and dirt therefrom as said valve moves to open position, the relative diameters of said valve head and guide being such that they cooperate when said valve is open to form an obstruction so related to said seat and passageway as to produce a Venturi flow through the assembly, the external diameter of the open end of said guide being equal to the diameter of said valve head adjacent said open end, the adjacent ends of said guide and head being shaped to permit the external surfaces of said guide and head to merge with each other to form, in effect, a single streamlined body when said valve is fully open.

REGINALD J. S. PIGOTT.