US2953350A - Orienting apparatus - Google Patents

Description

s. c. MOORE Y'ORIENTING APPARATUS 7 Sept. 20, 19 0 5 Sheets-Sheet 1 Filed Jan. 20, 1958 INVENTOR.

A GE/V f .Z@,\&J.,Y t/ 7/ w w w. g y 2 3 f A q v\ n 1 i Sept. 20, 1960 s. c. MOORE ORIENTING APPARATUS 5 Sheets-Sheet 2 Filed Jan. 20, 1958 5/0/7/9 C. Moa/e y INVENTOR Sept. 20, 1960 s. c. MOORE ORIENTING APPARATUS Filed Jan. 20, 1958 ORIENTING APPARATUS Stanley C. Moore, Midland, Tex., assignor to Drilco Oil Tools, Inc., a corporation of Texas Filed Jan. 20, 1958, Ser. No. 709,952 Claims. c1. 2551.6)

This invention relates to methods and apparatus for orienting a well member with respect to the low side of an inclined well bore in which the member is placed and further will indicate the absence of inclination of a well bore.

In both directional and conventional straight down well drilling it is frequently desired to change the direction of the well bore. In the case of straight down drilling the bore may unintentionally become deviated from the vertical and it becomes necessary to change direc tion to bring the bore back to vertical. In the case of directional drilling it may be desired to change from one direction of inclination to another. In both cases the procedure would usually be to position a whipstock in the well bore in such a position as to direct the drill bit in the desired direction. It is necessary to orient the whipstock relation to the well bore in order that the whipstock properly redirects the drill bit.

In the case of restoring a well bore to vertical, it is only necessary to position the whipstock so that it faces the low side of the bore and knowledge at the surface of the direction of deviation of the bore from vertical is unnecessary. Therefore, it is only needed to orient the whipstock with respect to the low side of the hole, which can be readily accomplished by means of the invention.

In the case of directional drilling, it is necessary to know the precise direction of the bore. This is preferably accomplished initially by the use of known well surveying apparatus. However, once the direction of the bore is known the present invention can be used to set a whipstock to redirect the bore by orienting it with respect to the low side of the bore for the vertical plane, including the line of direction of a well bore also includes the radial line from the low side of the hole through the bore axis.

If time and accuracy are not critical, it may be assumed that there is no twist in the drill pipe between the surface and the bottom, in which case the orientation of the apparatus of the invention relative to the uppermost strand of drill pipe may be determined by the rigid mechanical connection therebetween and the absolute direction of the inclined bore will be apparent at the surface from knowledge of the position of its low side and intent well survey by other means may be omitted, even in directional drilling.

There are other uses to which the subject invention may be put, such as orienting a side wall coring tool with respect to the low side of the well' bore so as to take a sample in a particular direction or so as to take succes-' sive samples at azimuthally spaced directions. However, for clarity in description the tool will be described hereinafter primarily with reference to its use in connection with drilling.

The apparatus of the invention falls within that class of orienting devices in which the information determined by the sensing device at the well bottom (or other below the surface location) is immediately indicated at the'surface through a telemetering system, making it unnecesa ball race having a flat bottom disposed normal to the lence and is also subject to becoming entangled with the indicate the inclination, as well as the absence of inclinasary to stop operations and wait for the sensing device to be brought to the surface,

Various devices to indicate the orientation of well conduit within inclined well bores have been proposed. For

example, there has been proposed an orientation member incorporated in a drilling string to vary the flow pres sure of fluids continuously pumped through the conduit as the conduit is continuously rotated through a preselected direction relative to the well bore inclination. This is accomplished by a ball member adapted to roll about axis of the conduit. A flow port is disposed within the race which is covered by the ball when the member is rotated ina particular direction relative to the direction of well bore inclination. Since the fluid pumped through the flow port is usually a drilling mud traveling at high velocity and having entrained drilling cuttings or the like, it is cliflicult for such a ball to respond only to gravity and cover the port as desired for proper operation. The ball is subject to being swept aboutby the fluid turbumaterials suspended in the drilling fluid.

It is therefore the general object of this invention to provide an inclination indication apparatus adapted for incorporation into a segment of well conduit which will tion, of the well conduit segment independently of the type or velocity of the well fluid pumped through said conduit.

It is a further object of the invention to provide method for using said apparatus.

By way of introduction it may be said that the invention includes a tubular housing to be inserted in the drill string between a drill bit assembly therebelow and a drill pipe thereabove. A downwardly opening check-throttle valve is disposed in the housing to control fluid flow therethro ugh. The valve includes a seat annularly disposed around the inside of the housing and a valve body adapted to seat thereon. The valve is spring biased upwardly, i.e. towards the closed position. There is a valve stem extending down from the valve body connected to the upper end of a piston. The piston is mounted for axial motion in a cylinder coaxially disposed in the housing and is held against rotation relative thereto. The cylinder is smaller than the housing, leaving an annular space therearound for fluid flow. Within the cylinder is a support on which a ball may roll around. The downward travel of the piston and hence the degree of opening of the valve is limited by engagement of the piston with the ball. There is a radially extending recess in the face of the piston so that if the ball is in the center of the support corresponding to no inclination of the well bore or if the housing is azimuthally positioned in the well bore so that the recess in the piston is in azimuthal register with the ball in the case of an inclined bore, the piston can move down farther and the valve open more, which is indicated at the surface by a drop in fluidpressure.

By separating the function of sensing the direction of inclination, which is performed by the ball and piston, from the function of telemetering the information to the surface which is performed by the valve, it is possible to completely isolate the ball from the action of the drilling fluid by enclosing it in the cylinder. Suitable sliding sealing means is provided as will be described hereinafter in more detail.

Other objects and advantages of the invention will become more apparent by reference to the following specification and claims taken in view of the accompanying drawings in which:

Figure l is a partly sectional View in elevation of a well bore containing a well conduit terminating in a well Patented Sept. 20, 1960 bore deflection tool with the orienting apparatus of the present invention incorporated therein;

Figure 2 is a longitudinal'sectional view taken at the axis of the orienting apparatus;

Figure 3 is a cross-sectional view taken at 33 of Figure 2;

Figure 4 is a cross-sectional view taken at 4-4 of Figure 2;

Figure 5 is a cross-sectional view taken at 5-5 of Figure 2;

Figure 6 is a cross-sectional view taken at 6-6 of Figure 2;

Figure 7 is a fragmentary longitudinal cross-sectional view taken at the axis of the apparatus at 90 from Figure 2 at a first condition of operation;

Figure 8 is a fragmentary cross-sectional view of the apparatus as shown in Figure 7 taken at a different condition of operation.

Now referring to Figure 1, there is illustrated a body 10, housing the apparatus of the present invention, incorporated into a string of well conduit 12. Conduit 12 is inserted in a well bore 14. Attached to the lower end of conduit 12 is a drilling assembly 16. As an example, a whipstock 18 is shown aflixed to drilling assembly 16. Drilling assembly 16, by means of the present invention, has been placed in position to provide deflection of the well bore, upon subsequent drilling, from the inclined position illustrated to the vertical.

At the earths surface conduit 12 is in connection with conventional drilling equipment (not shown) which includes a fluids circulating pump 20. Practice of the present invention requires knowledge of the fluids pressure through conduit 12 which is obtained at pump 26 by means of a pressure gauge 22.

Now referring to Figure 2, member is seen to house inclination orientation apparatus generally indicated at 24, which is adapted for insertion and removal through one end of housing member 10.

As shown in Figures 2 and 6, orientation apparatus 24 includes a generally cylindrical elongated body 26 which is retained within the housing It) at a preselected angle of orientation with respect to the housing by means of an orientation web member 68 connected to the lower end of said body. Orientation web 68 is provided with a plurality of longitudinal grooves '76 about the outer periphery thereof adapted for individual engagement with a key 72 supported within a groove 74 of housing 16. Body 26 may be placed within housing It) at any rota tional angle permitted by mutual registry of any web groove '70 with any housing groove 74. As shown, such registry may be had in 9 angular increments. Body 26 is longitudinally supported within the housing 18 by a removable supporting means 76, herein exampled as a snap ring, engaging the web member 68.

Body 26 is provided with an axially aligned cylinder 28 disposed within its lower end and an axial passage 36 disposed Within its upper end. Concentrically disposed in passage 36 is a valve seat 32 adapted for sealing contact with a valve plug 34 upon longitudinal movement of the plug within the passage. Valve plug 34 is attached to a piston rod 36, also positioned in axial alignment with passage 30. The lower end of piston rod 36 is in connection with a piston 38. Piston 38 is housed in reciprocating relation within cylinder 28.

As shown in Figures 2 and 5, piston 38 is adapted to reciprocate in splined relation Within cylinder 28 by provision of a groove 40 in piston 38 in registry with a key 42 in the wall of cylinder 28. Also provided in the lower face of piston 38, as shown in Figures 2 and 5, is a groove 44 extending from the periphery to the center of said piston of width and depth determined by a gravity responsible inclination means 46, herein I embodied as a spherical ball for example. Groove 44 terminates in the of the apparatus of the apparatus of the apparatus of the apparatus center of piston 38 in semi-circular shape about the axis of said piston of radius equal to the radius of the ball.

Ball 46 is supported by a piston stop member 48, rigidly disposed within cylinder 28 by retaining means such as snap rings. Stop member 48 presents a slightly concave face 50 to ball 46, the center of which is normal to the axis of said apparatus if the face is doubly convex, e.g. spherical, and the axis of revolution of which is coaxial with body 26 in any event, e.g., if the face 50 is singly convex as in the case of a conical surface like that shown in the drawing. As provided, ball 46 may randomlytraverse face 50 in direction and, in the case of a doubly concave surface, in magnitude responsive to the inclination of the axis of body 26 from the vertical. At such times that ball 46 has assumed a position upon face 50 which is in azimuthal registry with groove 44, then piston 38 is free to extend into cylinder 28 until supported by contact with piston stop 48. At such times that ball 46 has assumed any other position on the face 50 not in azimuthal registry with groove 44, then piston 38 may extend into cylinder 28 only such distance as permitted to initiate supporting contact with the ball 46, a less distance equal to the diameter of said ball.

As shown in Figures 2 and 3, valve plug 34 is maintained in a normally closed position relative to valve seat 32 by provisions of a spring 52 positioned in compressional support between body 26 and a web member 54 attached to piston rod 36. Piston 38 is maintained in a normally retracted position Within cylinder 28 by spring 52.

The upper portion of body 26 is provided in sealed relation with the inner walls of housing member 10 by a sealing means 56, herein provided as an O ring. As shown in Figures 2 and 4, the lower portion of body 26 is provided of lesser diameter than the interior of housing 10 to allow fluid flow therebetween. Fluid communication is provided between the axial passage 30, found in the upper portion of body 26, and the annular flow area provided between the reduced lower portion of body 26 and the housing 10 by means of flow ports 58 disposed in the walls of body 26.

A portion of cylinder 28 is provided in fluid isolated relation from the remainder of orientation body 26 by a sealing means 60, herein exampled as an O ring disposed about piston 38, and a second fluid isolating means, herein exampled as a piston 62 having an O ring sealing means 64. Piston 62 is disposed within cylinder 28 between stop member 48 and a fluid exhaust passage 66 found at the .lower end of the cylinder. Stop member 48 is webbed about its outerperiphery to permit by-pass'of fluids.

The isolated chamber thus created by piston 38 and isolating means 62 prevents any drilling fluids, or the solid material normally entrained in such drilling fluids, from entering into interfering contact with the ball 46 or face 56. As herein shown, the isolated chamber is filled with a clean light oil which serves to damp ball 46 from undue oscillation. Under certain conditions however, it is noted that the isolated chamber could be provided with equal utility as an air space. When the isolated chamber is filled with oil, the isolating means 62 performs the additional function of providing displacement for fluids displaced by the extension of piston 38 into cylinder 28.

The pressure of fluids pumped through the conduit 12 into the upper end of housing 10 is applied to valve plug 34 in opposition to the compression of spring 52. This fluid pressure overcomes the force of the spring and causes the plug 34 to retract from valve seat 32, permitting fluid flow through the passage 36. Movement of the valve plug 34 is transferred through piston rod 36 to piston 38, causing its extension into cylinder 28 to the greatest distance permitted by the ball 46.

If, as shown in Figure 7, the fluid pressure is applied at such time as the axis of the orientation body' 26 is inclined in correct direction to cause the ball 46.to

traverse face 50 to a position in azimuthal registry with the piston groove 44, then piston 38 may extend into cylinder 28 into direct support with stop member 48. If, as shown in Figure 8, orientation body 26 is inclined in any other direction, then ball member 46 will serve as an intermediate stop between piston 38 and stop member 48.

When piston 38 has fully extended into contact with stop member 48, valve plug 34 stands fully retracted from valve seat 32, allowing maximum fluid flow through passage 30. When ball 38 is positioned on face 50 to provide an intermediate support for piston 38, then valve plug 34 is retracted less from valve seat 32 to a position permitting less fluid flow through passage 30.

Thus, when the pump 20 is providing a fluid flow through the well conduit 12, the pressure indicated at the gauge 22 to provide such flow will be less when valve plug 34 is fully retracted and greater when the valve plug is only partially retracted.

It is now seen, when housing member is positioned Within a section of well bore inclined from the vertical, that the valve plug 34 will permit maximum fluid flow through passage 30 only when the ball 46 has assumed a position on the face 50 responsive to an inclination of apparatus 24 which will permit registry of the ball with the piston face groove 44. Bearing in mind that the orientation apparatus 24, by means of orientation web member 68, may be preselectively oriented with the housing 10 and therefore with the well conduit 12, it is seen that the position of ball 46 on the face 50 may be known at the earths surface.

In operation the well conduit containing apparatus 24 is lowered into the well bore. Fluid pressure is provided by the pump 20. A reading is taken of the fluid pressure at the gauge 22. Such pressure is then released and the well conduit 12 rotated .a small angular increment. Pump pressure is again applied and thepressure appearing at gauge 22 noted. Such intermittent application of pump pressure and incremental rotation of well conduit 12 is continued until a substantial drop in pressure is noted at gauge 22. Such pressure drop indicates a full opening of the fluid passage 30 provided by full extension of piston 38 into cylinder 28. Since the relative angular relation of the body 26 to the drilling assembly 16 and whipstock 18 may be preselected, the Whipstock may thus be oriented in relation to the direction of inclination of well bore 14 as desired.

It is seen, by reference to Figures '2 and 5, that the ball 46 will be in the center of face 50 when the orientation apparatus 24 is in vertical alignment. As provided, the ball 46 will be in registry with the semi-circular termination of groove 44 upon such vertical alignment and will permit full extension of the piston 38 into cylinder 28. Thus, the apparatus may be used to determine absence of inclination as well. To make such determination well conduit 12 is turned in angular increments in conjunction with intermittent application of fluid pressure from the pump 20. A reading is taken at gauge 22 upon each pressure application. When the orientation apparatus 24 is in the vertical, pressure gauge 22 will indicate a continued lower pressure, permitted by continued registry of the centered ball 46 in the piston groove 44, throughout a complete revolution of conduit 12.

It is pointed out that the drilling fluids and suspended foreign materials may pass through and about orientation apparatus 24 at any velocity without detrimental effect to the inclination indicating ability of the invention.

Though only a preferred embodiment of the invention has been disclosed herein, it is obvious that certain substitutions or modifications thereto may be made by those 6 skilled in the art without departing from the spirit or scope of the invention as'defined'in the appended claims.

That being claimed is:

1. In inclination orientation apparatus the combination of a generally cylindrical body being adapted for placement in axial alignment within a well conduit, a chamber defined within said body in fluid isolation from the interior of said conduit, a first stationary inclination element disposed within said chamber having a dished face positioned with its lowest point (as determined when the axis of said body is vertical) disposed at the axis of said body, a second gravity actuated inclination member in contact with said face being free to assume a position on said face indicative of the direction of inclination of the axis of said body from a vertical position, a longitudinally displaceable control member positioned in splined relation within said chamber, said control member having a groove in its lower surface for receiving said second inclination member when said control member assumes a position with said groove lying in the vertical plane through the axis of said body, said control member being adapted for greater displacement to a first position when registered with said second inclination member and for lesser displacement to a second position whennot registered with said second inclination member, a normally closed valve means disposed with said body in linked relation to said control means being adapted to be opened by fluid flow through said conduit to positions responsive to the displacement of said control member to create flow pressure variation within said conduit responsive to said positions.

2. An inclination orientation apparatus comprising, a generally cylindrical body being adapted for placement in axial alignment within a well conduit in pro-selected rotational relation to said body, a chamber adapted to contain a damping fluid defined by said body in fluid isolation from the interior of said conduit, a first stationary inclination element disposed within said chamber having a generally concave face positioned coaxial to the axis of said body, a gravity actuated ball member in contact with said face being free to assume a position on said face indicative of the direction of inclination of the axis of said body from a vertical position, a displaceable control member positioned within said chamber being adapted to maintain constant rotational relation with the axis of said body during said displacement, said control member having a radial recess on its face adjacent said ball member for receiving said ball member when said ball member assumes a position on said face along a particular radius extending from the axis of said body, said control member being' adapted for displacement to a first position when registered with said second inclination member and for displacement to a second position when not registered with said second inclination member, a normally closed valve means disposed within said body in linked relation to said control member being opened by fluid flow through said conduit to create pressure variation within said conduit responsive to the displacement of said control'member.

3. In inclination orientation apparatus the combination of a generally cylindrical body being adapted for placement in axial alignment within a well conduit, a chamber adapted to contain a damping fluid defined within said body in fluid isolation from the interior of said conduit, a first stationary inclination element disposed within said chamber having a generally concave face positioned coaxial to the axis of said body, a gravity actuated ball member in contact with said face being free to assume a position on said face indicative of the direction of inclination of the axis of said body from a vertical position, a longitudinally displaceable piston positioned in splined relation within said chamber, said piston having in its face that is adjacent said ball member a radial recess for receiving said ball member when, 5 said second inclination member assumes a position onv said face along a particulanradius extending from the axis of said body, said-piston'being adaptedfor displacement to a first position when registered withsaid ball member andforfldisplacement to asecond position when not. registered with said ball member, a valve means disposed with said body in linked relation-to said piston being opened by fluid flow through said conduit to-positions responsive to the displacement of said piston to: create flow. pressure variations within said conduit responsive to said positions.

4. An inclination orientation apparatus comprising, a generally cylindrical body beingadapted for placement Within a well -conduit in-preselected relation tosaidconduit, a chamber defined within saidbody, a firststationary inclination element disposed within said chamber having a dished.-face positioned with-its lowest-point as determined when the axis of said body is verticaldisposed at said. axis; asecondgravity-actuated inclination member in contactwith said face being free to'assume a position on said face indicative ofsaid inclination of the axis. of said body from a verticalposition,--a longitudinal-t ly displaceable control member--positionedinsplined relation within said chamben rneans to isolatesaidcham her from any fluidsin the interior-of said conduit, said control member having aarecess in its lowersurface forreceiving said secondinclination member only when-saidsecond inclination member-is particularly positioned on said face, said control member being-adaptedfor displacementto a first position when registered with said second inclination member and for displacement to a second position when not registered with said secondinclina tion. member, a valve disposed with saidbody in=linked relation tosaid control means being opened --byfluidflow pressures through said conduit to flow positions responsive to the displacement =of said control member.----

5. In a method of'orienting asegment of well conduit relative to-the inclinationof a-well bore the-steps-of in corporating an inclination orientation means into the well-conduit in preselected rotational relation-to said conduit,-said orientation meansbeing adapted toprovide a first restriction to fiuidflow through said conduit uponsaid conduit being inclined in a singledirection and to providea second' difierent restriction to fluid flow upon said conduit being inclined in any other direction, inserting-said conduit into a well bore, applying a-fluid-flow through said conduit, measuring .apressure required toproduce said flow, halting said fluid-flow,:rotating said conduit an angular incrementL-withinsaid well bore,- again applying said'fluid flowthrough said conduit, again measuring a pressure caused-by said-fluid flow, repeating said rotation of said conduit and intermittent applica-- tion of said fluid flow until--a-diiferent pressure is measured, said different pressure being indicativeof said orientation means being-inclined in said direction. I

6. In a method of detecting the inclination of a-segment of well conduit-Within a well bore the steps of incorporating an inclinationmeans being adapted top-ro videa first restrictionto fluidflow through said conduit when said conduit is vertical and is inclined in a direction preselected-in relationto said conduit and to provide a second restriction to :fiuid flow upon said conduit being inclined in any other direction relative to said conduit,

into a Well conduit, insertingsaid-conduit-into a-well bore, applying-a --fluid flowthrough said conduit, measuring a pressure required to produce said flow, halt ing "said iiuid flow, rotating said conduit an-angular increment within said well bore, again applying said fluid flowthrough said conduit-,- again measuring a-pres sure caused by'said fluid flow, repeating thesteps of rotating said conduit interposed bythe steps of; applying said fluid flow and determining said-pressures throughat least one revolution ofsaid conduit, a change in the pressures thus determined at'any rotational increment of said conduit'being' indicative of inclination of; said con-- duit and no change in the pressures thus determined at every rotational increment being indicative of no inclination of said-conduit. r 5.; .ns, .-7. An inclination orientationapparatus conprisingg-a generally cylindrical body being adapted for placement within a well conduit in preselected relation-to saidconduit, a first stationary inclination elementv disposed within said body having atface positionedttransverse:to the axis of said body, a second gravity actuated inclinationmember in contact Withsaid face being free to rassurne a position on said face indicative of said inclination of the axis of said body from a vertical position, a longitudinally displaceable control member positioned: insplined relation within said body, said control member having a recess in its lower surface adapted for registrywithxand receptionof said second inclination member-only. when said second inclination member assumes one of a particular group of positions on said face, said control'member being adapted fortdisplacement toa, first position when registered with said second inclination member and-for displacementto a secondposition when not registered with said 'second inclination member, and: a valve dis-- posed within said body in linked relation tosaid control member being opened by fluid flowpressures through said. conduit to flow positions responsive to the displacement of-saidcontro1member. 8. Well apparatus comprising a first member, having a dished surface, a ball on-said surface, a second-member, means mounting said second member for-reciprocation relative to said dished memberalong an axis,etl1e low point of said dished surface being-onsaidaxis when said-axis is vertical, said second member haVing ar-adial recess on the side thereof facing said first member-adapted to, receive said ball when in register therewith, valve means, and means connecting said valve means to-said second member .to control the possible degree of'movement of said valve means in accordance with the-possible extent of axial movement of said second member'toward" saiddished surface as determined by-the position of said ball on said surface relative to said radial recess." 1

9. In combination with the-apparatus of claim 8,-a tubular member adapted for connection in a pipezstring and housing said apparatus with said-axis of-saidapparatusextending in the same direction as the axis of said tubular member, means sealing between-said-valvemeans and said tubular member'to-cause all fluid-passing through said tubular member to pass through said valve means, and locating means holding-said first'member in preselected azimuthal relation to;said tubular-memben 10. The combination of claim 9 in which said locating means includes a spider connected to-said" first member to have a constant azimuthal relation-thereto having-a plurality of equallyazimuthally spaced webs, each-web having a slot in its outer peripheral end,- saidtubular member having a plurality-of equally azimuthally spaced grooves on its inner periphery, the number of' grooves being different from the number of slots with no-com mon divisor forsaid numbers, andltey means to-hold a selected one of said slots in alignment with a selected one of said-grooves. i ll. Incombination-with the-apparatus of claim 8; means forming a chamber having a first portion w-ith any internal cylindrical surface,-said second member havinga cylindrical piston portion received insaid cylindrical surface portion of said chamber for axial movement there in, means sealing between said piston portion -andcylindrical surface portion of said chambensaid first-member being also disposed in saidchamber, said ball being dis-- posed in said; chamber between said first -and--second members, said means forming a chamber-having a=sec-- ond cylindrical surface portion, a--second--cylindrical piston axially slidably disposed in saidsecondcylindrica-l surface portion of said chamber, means sealing between said second piston and'said secondcylindricalsurfaceportion, said second piston being on the opposite side of said first and second members from said first piston,

said chamber being filled with a liquid, said chamber forming means being open at both ends beyond said pistons to expose the exterior ends of said pistons to the pressure outside said chamber forming means.

12. In combination with the apparatus of claim 11, tubular means, said valve means including a valve and seat, said tubular means connecting said seat with said chamber forming means, said second member being connected to the valve of said valve means, a valve stem connected to said valve, and compression spring means bearing on said valve seat and engaging said valve stem urging said valve to closed position.

13. An orientation determination apparatus comprising a tubular housing adapted to be incorporated into a string of well conduit above a drilling assembly, a generally cylindrical elongated body disposed in said housing, said body being provided with an axial passage in its upper portion and an axially aligned cylinder in its lower portion communicating at its upper end with said axial passage, the lower portion of said body having a smaller external diameter than the inside diameter of said housing leaving an annular fluid passage therebetween, the lower portion of said body having ports therethrough placing said annular fluid passage in communication with the interior of said cylinder, means between the lower portion of said body and said housing holding said body against axial motion relative to said housing and in preselected azimuthal angle of orientation relative to the axis of said housing, the last said means having passage means therethrough placing said annular passage in communication with the portion of said housing therebelow, means sealing between the outside of the upper portion of said body and the inside of said housing, a valve seat disposed concentrically in said passage about the inner periphery thereof, a piston disposed in said cylinder for reciprocation therein below said ports, a piston rod connected to the upper part of said piston and extending concentrically upwardly through said passage and above said seat, a valve plug attached to said piston rod and adapted to engage the lower side of said valve seat, a web member attached to said piston rod above said seat, a helical spring disposed around said piston rod between the upper side of said valve seat and said web member and hearing at its ends against said seat and web member and urging said valve plug against said seat, means holding said piston in splined relationship within said cylinder comprising a key in the wall of the cylinder, said piston having a groove parallel to the cylinder axis slidably receiving said key, said piston having a groove in its lower face extending radially from the center of the piston to the periphery thereof, a stop member secured within said cylinder below said piston, the upper face of said stop member being concave, a ball disposed on said upper face of the stop member, said ball having a diameter less than the width of said groove, said ball limiting the downward movement of said piston toward said stop member when out of registry with said groove and thus limiting the possible movement of said valve plug away from its seat when said ball is out of registry with said groove to a lesser movement than is possible when said ball is in registry with said groove.

14. The combination of claim 13 with means sealing between said piston and cylinder, a second piston disposed in said cylinder for reciprocation therein below said stop member, means sealing between said second piston and said cylinder, said stop member having passage means therethrough placing the space in said cylinder between the stop member and second piston in communication with the space in said cylinder between said stop member and the first said piston, said spaces being filled with liquid, said cylinder having passage means therethrough placing the space in the cylinder below said second piston in communication with said annular passage between said body and said housing.

15. The combination of claim 13 in which said means holding said body in said housing comprises a web member connected to said body, said web member having a plurality of azimuthally spaced radial arms each having a groove at its outer end, a key received within a selected one of said grooves, said housing having a plurality of azimuthally spaced slots in its inner face, the spacing of said slots being difierent from that of said grooves, said key also extending into a selected one of said slots, and a snap ring engaging said web member and said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,046,956 Lynch et a1 July 7, 1936 2,207,505 Bremner et a1 July 9, 1940 2,303,360 Irwin et a1. Dec. 1, 1942 2,600,125 Natland et a1 June 10, 1952

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