US3335756A

US3335756A - Automatic sequence valve

Info

Publication number: US3335756A
Application number: US397207A
Authority: US
Inventors: Hal W Mcpherson
Original assignee: Peters and Russell Inc
Current assignee: Peters and Russell Inc; ITT Inc
Priority date: 1964-09-17
Filing date: 1964-09-17
Publication date: 1967-08-15
Anticipated expiration: 1984-08-15

Description

Aug. 15"T 1967 H. w. MCPHERSON AUTOMATIC 'SEQUENCE VALVE Filed Sept? 17, 1964 a k a N v l Q l Vt` n I gm v 4 N N-l M "W su 300ML-Rm United States Patent O 3,335,756 AUTOMATIC SEQUENCE VALVE Hal W. McPherson, Tampa, Fla., assignor to Peters & Russell, Inc., Springfield, Ohio, a corporation of Ohio Filed Sept. 17, 1964, Ser. No. 397,207 17 Claims. (c1. 137-628) This invention relates to fluid ow control Valves, and particularly to sequence valves automatically directing a pressure fluid to a succession of outlets.

The object of the invention is to simplify the construction las well as the means and mode of operation of control valves, whereby such valves may not only -be economically manufactured, but will be more eflicient and satisfactory in use, adaptable to a wide variety of application, and be unlikely to get out of order.

An object of the invention is to provide a sequence valve of general utility especially characterized by an ability to direct an incoming pressure fluid, for example water, to successive outlets in a single cyclic operation.

Another object of the invention is to carry out an operation as described automatically in response to a single operator initiated control motion externally of the Valve.

A further object of the invention is to provide a valve characterized as described functioning hydraulically without the use of solenoids or other electrical controls.

Still another object of the invention is to provide an automatic sequence valve `of such inexpensive, reliable construction so as to adapt it for use in domestic and other water systems of private or public use, for example as a flush valve in water closets.

A further object -of the invention is to provide a control valve possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein is shown one but obviously not necessarily the only form of embodiment of the invention,

FIG. 1 is a view in longitudinal section of lan automatic sequence valve in accordance with the illustrated form of the invention, the valve being shown in a normal, nonoperating, position;

FIG. 2 is a view similar to FIG. l, showing the valve as it appears after operator actuation thereof to initiate a cycle of operation; and FIG. 3 is a view similar to FIGS. 1 and 2, showing the valve as it appears at the end of a first stage of return motion from the fully actuation motion yof FIG. 2.

Like parts are indicated by similar characters of reference throughout the several views.

The invention is illustratively disclosed in a ush v-alve for water closets. As such, the valve functions in each cycle of operation to direct fresh water under pressure through a first youtlet where it forms a jet for grinding and disintegrating purposes and then to close olf flow to the said first outlet and open flow to a second outlet where the incoming fresh water is directed to serve as a flushing or ejecting jet. Successive use of the separate outlets is predetermined to allow =a part of each operational cycle to each purpose, with the invention contemplating a means for selectively varying the length of the operational cycle. i

Referring to the drawings, in its illustrated embodi- 3,335,756 Patented Aug'. 15, 1967 ice ment the invention comprises a body 1l) which for convenience -of manufacture and assembly is comprised of three superposed castings 11, 12 and 13 suitably held in a connected relation as by means of bolts 14 (one shown). End casting 11 is formed with a recess 15 opening through one end thereof and with a projecting annular rib 16 in surrounding laterally spaced relation to the recess at the said one end of the casting. A lateral port 17 opens into the recess 15 and is threaded for connection in a uid flowing system, the port 17 defining the first mentioned outlet above described through which the grinding jet is discharged. Intermediate casting 12 is formed with a longitudinal through bore 18 and with a large counterbore 19 vopening through one end of the casting. A further counterbore 21 in the said one end of the casting is adapted to receive the rib 116 on casting 11, an arrangement of the parts as described placing the counterbore 19 in an opposed relation to recess 15 to form a substantially continuing interior body chamber. Further in the intermediate casting 12 is an annular chamber 2,2 in surrounding relation to counterbore 19 and opening through counterbore 21 :in a manner to communicate with recess 15 of casting 11 in an assembled position of the parts as shown. A lateral port 23 in the casting 12 communicates with annular chamber 22 and denes the second mentioned outlet as above described through which the ejector or flushing jet is discharged. Further in the casting 12 is a threaded port 24 communicating with the counterbore 19. This is a utility opening which may be used, for example, for the installation of vacuum breaking means inhibiting the creation of less than ambient pressure in the valve interior chambers. Such a means would comprise a check valve or the like operating to permit ambient pressure access to the counterbore 19 in the event the pressures therein fell below a predetermined value which might allow backflow to the valve through the outlets 17 or 23. On what may be considered the underside of the casting 12, or that side opposite the one in which the counterbore 21 is formed, an annular recess 25 is in surrounding relation to bore 18. At this location, and ,at the extremity yof the wall separating counterbore 19 and annular passage 22, the casting 12 is formed with respective valve seats 26 and 27. Finally, the same said underside of :intermediate casting 12 is formed with a projecting annular rim 2S.

The other end casting 13 has an annular rib 29 at one end thereof adapted to seat within the projecting rim 28 of casting 12. Also formed in the casting 11 is `a cylindrical chamber 31 open at one end to achieve an aligned, facing relation to the bore 18 in casting 12 and having a diameter to achieve a surrounding spaced relation to the valve seat 26 and provide for a iiow passage 32 between its inner diameter and the valve seat. Surrounding the cylindrical chamber 31 is an annular chamber 33 into which opens a threaded port 34 defining the aforementioned pressure fluid inlet.

The port 34 communicates, in the illustrated instance, with a source of fresh water under pressure. Under control of valve means to be described, and .in repeated cycles of operation, the water is admitted to the body interior, is directed first to outlet 17 and then to outlet 23 and finally is shut olf from communication from the valve interior. The valve means includes an annular flap type diaphragm valve 35 in a superposed overlying relation to annular chamber 33 in end casting 13. The valve 35 is made of a resilient deformable material and has its outer peripheral edge clamped between the rib 29 on casting 13 and the adjacent end of casting 12 within projection 28 thereon. The inner peripheral edge of the valve rests on the wall separating annular lchamber 33 and icylindrical chamber 31 and is deilectable` upward into the space defined by recess 25 whereby fluid fiow may take place from chamber 33 to chamber 31 over the upper end of the described wall and through passage 32. Opening of the valve as described is a function of a pressure diiference between chambers 33 and 31, with reverse flow, that is, from chamber 31 to chamber 33, being denied. A screen 36 underlies the flap valve 35 for filtering and support purposes.

In an overlying, superposed relation to the annular chamber 22 in casting 12 is a flap valve 37 similar to the valve 35. The outer peripheral edge of the valve 37 is clamped between the annular rib 16 on casting 11 and the bottom of counterbore 21 in casting 12. The inner peripheral edge rests on the wall seat 27 on the wall separating chamber 22 from counterbore 19. The valve is in this instance unitarily joined to a divergently extending terminal portion 38 acting as a covering for a sleeve 41. The latter is an integral projected part of a plate 42 having a radial flange 43 in overlying relation to the valve 37. A through opening 44 in the plate 42 is elongated by virtue of the projected sleeve 41 and provides for communication between the different portions of the body interior as represented by counterbore 19 and recess 15. Plate 42 is relatively rigid, being made of a plastic or like material suitably resistant to corrosion and light in weight. Valve 37, along with plate 42, is adapted to lift from seat 27 in order that uid may flow from `counterbore 19 to chamber 22 with flow from chamber or recess to chamber 22 being denied.

Flow from the cylindrical chamber 31 to the interior body chamber as defined by counterbore 19 and recess 15 is controlled by a piston valve means 45 comprising a spool element 46 and a conical valve element 47 positioned on one end of the spool 46. Element 47 is adapted to engage valve seat 26. So engaged, as viewed in FIG. l, flow to the valve interior from inlet 34 is denied. A cup lshaped packing 48 on the exterior of spool 46 has its periphery turned upward along the side of cylindrical chamber 31 or in a direction toward bore 18. As a result, liquid trapped beneath the valve means 45 in the closed bottom of chamber 31 may readily be displaced by movement of the valve means downward in the chamber but flow to the bottom of the chamber around the exterior of the valve means during travel thereof in a reverse direction substantially is prevented. Wrapped around the spool 46 is a flexible capillary tube 49, one end of which communicates with the chamber 31 at the open end thereof at one end of valve means 45 and the other end of which communicates with the closed end of chamber 31 at the opposite end of valve means 45. The result is that pressure fluid admitted to the open end of the chamber 31, through passage 32, may find its way to the bottom of chamber 31 through the tube 49 but at a relatively slow rate determined by the bore of the tube and the length thereof.

The aforementioned through opening 44 in the plate 42 is controlled by a exible deformable valve member 51 having a cylindrical body portion 52 and a radial ilange portion 53. The latter exceeds in diameter the width of opening 44 and is adapted to be received within such opening in a manner to assume a deected position when received therein effectively to close such opening against flow from chamber or counterbore 19 to recess 15.

Actuation of the valve means 45 and valve member 51 is by a rod or stem 54 which extends axially through the body 10. Intermediate its ends the valve stem passes through the valve member 51 and is connected thereto through abutments 55 and 56 pinned to the stern. One end of the stem projects toward the bottom of cylindrical chamber 31, passing through valve means 45 and having a nut 57 threaded thereon. The nut 57 and a longitudinally spaced abutment member 58 on the stem holds the valve means 45 to the stem for unison longitudinal adjustment therewith. The opposite end of stem 54 projects through and beyond upper end casting 11, passing 4 through an opening 59 therein and through a projecting integral boss 61. The latter receives a compression spring 62 in surrounding relation to the stern 54 and abutting a member 63 pinned to the stem.

Also pinned to the valve stem 54, in the body 10, in recess 15, is a pusher element 64 having circumferentially spaced apart ribs 65 on what may be considered its underside or that side facing the plate 42. Member 64 -serves a purpose in holding plate 42 and valve 37 to a position of contact with valve seat 27 in a manner and for a purpose which will hereinafter more clearly appear.

Valve stem 54 is movable in an inward stroke and an outward stroke relative to the body 10` in an operational cycle of the valve. One end thereof projects, as described, outside the body 10 and is deflectable by hand through the inward stroke with the return stroke being effected automatically by fluid pressure and by the urging of spring 62. The parts of the valve normally assume a position as shown in FIG. 1 wherein the stem 54 is projected outwardly. Element 47 of Valve means 45 is at this time engaged with seat 26 closing ow from the inlet 34 to the valve interior. Also valve 51 occupies a position within opening 44, near what may be considered the upper end thereof, effectively closing this opening. Also pusher member 64 is elevated relatively to the plate 42. The system accordingly is non-operating, with no water pressure being permitted to reach either outlet 17 or 23. Upon depression of the stem 54, however, by a manual inward thrust thereof from the position shown in FIG. 1 to the position shown in FIG. 2, valve means 45 is unseated with reference to valve seat 26 and valve member 51 is carried through any beyond opening 44. Also, and near the end of such inward stroke, the pusher member 64 engages and presses upon the plate 42, holding the assembly further comprising valve seat 37 upon seat 27.

At this time, therefore, water is free to enter inlet 34, to ow past valve 35 and through passage 32 into the upper part of cylindrical chamber 31. There it passes through the bore 18 into counterbore 19 and on through opening 44 into recess 15. Valve 37 is at this time closed and held closed by pusher member 64. Accordingly the water pressure in counterbore 19 is denied access to annular chamber 22 and outlet 23. In recess 15, however, the water has free access to outlet 17 and flows out such an opening to assume its character as a grinding or disintegrating jet. The valve stem 54 may be released immediately upon actuation to the inward position as shown in FIG. 2, with the return stroke and the shifting of flow from outlet 17 to outlet 23 being automatically initiated and controlled. The force for such return stroke is provided by the spring 62 and by water pressure acting on the valve 51 as it flows to opening 44. The elongated nature of opening 44 locates valve 51 in a relatively adjacent position thereto as compared to valve means 45 which is thrust a greater distance from its seat 26. Accordingly, in an early part of the return or outward stroke of the valve stem 54 valve 51 enters and closes opening 44 (FIG. 3). This occurs while the valve means 45 remains open. Hence water pressure, although cut off from recess 15 remains in counterbore 19. As a result valve 37 and plate 42 are lifted from seat 27, allowing water to flow from counterbore 19 over seat 27 into annular chamber 22 and outlet 23. Pusher member 64 rises from plate 42 at the start of the return stroke. However, at this time the recess 15 continues to be energized with water pressure which is applied over the entire upper surface of the assembly comprising plate 42 and valve 37. A greater such surface is thus exposed to the pressure in the recess 15 than is exposed to the pressure in counterbore 19 so that the Valve 37 remains closed until such time as the valve 51 actually moves within and closes opening 44. When valve 51 closes, and valve 37 opens, water continues to flow through the valve body to outlet 23 until the valve element 47 of means 45 reengages seat 26, whereupon all flow is cut off.

The described arrangement of the valve means 45 1n cylindrical chamber 31, with cup shaped packing 48 and capillary tube 49, is such as to interpose a time delay in the return movement of the valve means 45 and thereby of the stem 54 and connected parts. Thus the valve means 45 moves readily to the bottom of chamber 31 in response to the manually effected inward stroke of the stem since liquid in the bottom of the chamber may be displaced around packing 48. As the valve means attempts to return in the opposite direction, however, access of water to the bottom of chamber 31 around the packing 48 is effectively denied. Thus, the valve means can move outwardly, under the urging of fluid pressure and of spring 62, only as rapidly as water can be supplied to the ybottom of the chamber, balancing the pressures at opposite ends of the valve means. The slender bore of tube 49 reduces the speed of this operation, and, it will be understood that the speed of movement may be varied by suitable variation in the structural -characteristics of the tube. In general the rate of movement of the valve assembly comprising stem 54, valve means 45 and valve member 51, is predeterined to allow sufiicient time for adequate discharge of both the grinding jet and iiushing jet. In the illustrated instance approximately half of the return stroke is allowed for each. This may be varied by suitably adjusting the valve member 51 along stern 54 whereby it may close opening 44 at an earlier or a later point in the return stroke of the valve assembly.

As shown in FIG. 3 when the valve member 51 reaches a closed position relative to opening 44, during the return stroke the pusher member 64 is substantially elevated relative to the plate 42. During the interval of iiow to outlet 17, however, the valve 37 has been held closed as described to the valve in a direction to maintain it closed. The member 64 serves a function in holding the valve 37 closed during the initial rush of water through counterbore 19 and through opening 44 to the recess 15.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes Iof putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of Athe appended claims.

Having thus described my invention, I claim:

1. An automatic sequence valve, including a body having a pressure iiuid inlet and first and second outlets, a chamber in said body in communication with said inlet and said outlets, first and second valves controlling iiow respectively from said inlet to said chamber and from said chamber to one of said outlets, a third valve controlling flow from said chamber to the other one of said outlets, said third valve being a normally closed valve opened by a pressure differential Ibetween said chamber and the said other outlet, a valve stem slidable in said "body having motions in opposed senses therein, means for opening said first and second valves in response to motion of said stem in one sense and utilizing a first part of the motion of said stem in the opposed sense to close said second valve and a second part of the same said motion to close said first valve, and other means utilizing motion of said stem in said one sense to hold said third Valve against opening, said other means releasing said third valve during motion of said stem in the said opposed sense.

2. An automatic sequence valve, including a body having a pressure liuid inlet and first and second outlets, a

chamber in said body in common communication with said inlet and said outlets, a pressure responsive valve unit transversely disposed in said chamber and adapted to occupy a seat closing said chamber from communication with one of said outlets, said unit presenting a surface to pressure fluid in said chamber to apply the pressure difference between said chamber and said one outlet in a direction to open said valve and presenting an opposite larger surface to pressure fluid at the other one of said outlets to apply the pressure difference between said other outlet and said one outlet in a direction to seat said valve in a closed position, said valve unit having an opening therethrough communicating said chamber with said other outlet, a rst valve controlling said last mentioned opening, a second valve controlling flow from said inlet to said chamber, and a stem reciprocable in said body opening and closing said first and second valves and applying a force during a part of its movement to m-aintain said pressure responsive valve seated in a closed position.

3. An automatic sequence valve according to claim 2, characterized in that in one extreme position thereof said stem occupies a position holding s-aid first and second valves open and said pressure responsive valve closed.

4. An automatic sequence valve, including a body having a pressure fluid inlet and rst and secondoutlets, said outlets being in parallel relation to one another, said body defining a Valve seat intermediate said inlet and said outlets and opposite said seat a closed cylindrical chamber, a piston valve received in said chamber and movable in opposite directions therein to engage and be disengaged from said seat to deny and to allow flow of pressure fluid from said inlet to said outlets, a stem reciprocable in said body and connected to said piston Valve for operation thereof, another valve operable by said stem during portions of the movement of said piston valve to open and close flow to one of said outlets, said stem opening said piston valve and said other valve during motion in one sense and closing said piston valve and said other valve during motion in an opposed sense, and means interposing `a time delay in the motion of said stem in a direction to engage said piston valve with said seat.

5. An automatic sequence valve according to claim 4, characterized in that said last named means is a capillary tube communicating with opposite ends of said cylindrical chamber at opposite ends of said piston valve.

6. An automatic sequence valve, including a body having a pressure fluid inlet and first and second outlets, a valve stem reciprocable in said body and having a portion extending outside the body to be manually adjusted in an inward stroke relatively to said body', yielding means urging said stem in a return direction or in an outward stroke, means interposing a time delay in the outward stroke of said stem, valves operated by said stem in different parts of the motion thereof controlling flow from said inlet and to one of said outlets and another pressure iiuid responsive valve controlling flow to the other one of said outlets, and means on said stem to hold said other valve closed at the endof the inward stroke of said stem.

7. An yautomatic sequence valve, including a body having an inlet and first and second outlets, a normally closed first valve controlling liow to said first outlet and adapted to open under the pressure of fluid admitted to said body from said inlet, a second valve controlling ow from said inlet to said body land a third valve controlling flow from said body to said second outlet, a valve ,stem movable in reciprocating inward and outward strokes in said body and connected to said second and third valves to dene a valve assembly, and means utilizing the motion `of said valve assembly to apply a holding force to said pressure responsive first valve during a part of the movement of said assembly.

8. An automatic sequence valve, including a body having 'a pressure fluid inlet and longitudinally spaced apart first and second outlets, a pressure responsive valve unit transversely disposed in said body intermediate said outlets defining first and second chambers therein and normally occupying a seat closing said first outlet from communication with said inlet through said rst chamber and movable by pressure fluid admitted to said body from said inlet to an open position, said valve unit having an opening therethrough for access of pressure uid from said first chamber to said second chamber, the latter communicating with said second outlet, said valve unit exposing a larger surface area to said second chamber than to said first chamber whereby the resultant iiuid pressure may be applied urging said valve unit to a seat closing said first outlet, and a valve assembly reciprocable in said body including a valve movable to yand from a position closing iiow from said inlet into said rst chamber and another valve movable to and from a position closing flow from said rst chamber to said second chamber through said opening in said valve unit.

9. An automatic sequence valve according to claim 8, characterized in that said valve assembly further includes a stem connected to said other valve and extending outside said body for manual actuation.

10. An automatic sequence valve according to claim 8, characterized in that said valve assembly further includes means operating in a part of the reciprocating motion of said assembly to hold said valve unit to a seated closed position.

11. An automatic sequence valve, including a body having a pressure iiuid inlet and outlet means, valve means in said body controlling uid flow from the inlet to the body interior and from the body interior through said outlet means, said valve means including a iluid pressure responsive valve controlling flow through said outlet means, actuating means movable in inward and outward strokes in said body operating said valve means, and means on said actuating means operable near the end of the inward stroke thereof to hold said pressure responsive valve closed until said actuating means begins its outward stroke.

12. An automatic sequence valve according to claim 11, characterized by means interposing a time delay in the outward stroke of said actuating means.

13. An automatic sequence valve, including a body having a pressure fluid inlet and a pair of outlets, one of said outlets communicating with the body interior through a valve seat intermediately disposed between said inlet and the other outlet, valve plate means resting on said seat to close ow to said one outlet and adapted to be lifted therefrom by pressure fluid admitted to the body interior through said inlet to open flow to said outlet7 said valve plate means having an opening therethrough for access of the admitted fluid to the interior of the valve body beyond said seat, said valve .plate exposing a greater surface area to the pressure uid beyond said seat then in advance thereof whereby in the presence of pressure at said other outlet in said body a resultant pressure is applied to said valve plate in a direction to seat it in a closed position, a valve stem received in said body and passed through the opening in said valve plate and extending to said inlet, valves on said stem respectively controlling iiow to said inlet and through the said opening in said valve plate, said valve stern extending outside the body and being manipulative 4through an inward stroke to open said inlet and said opening through said valve plate, and means for moving said stern outward in a return stroke, said valves being arranged on said stem in a manner to close said opening in one part of the return stroke and to close said inlet in another later part of the return stroke, closing of said opening reducing the pressure beyond said valve plate and allowing said plate to lift to an open position communicating said inlet with said one outlet.

14. An automatic sequence valve according to claim 13, characterized by means on said stem operable near the end of the inward stroke thereof to apply a supplemental pressure maintaining said valve plate seated while pressure iiuid flowing from said inlet passes through said opening in said valve plate and establishes a pressure at said other inlet sutiicient to hold said valve plate seated.

15. An automatic sequence valve according to claim 13, characterized by means interposing a time delay in the return stroke of said stern, the pressure fluid flowing during a part of such return stroke to said other outlet through said opening and owing during the balance of the return stroke to said one outlet.

16. An automatic sequence valve for directing pressure uid sequentially to rst and second outlets spaced longitudinally and differentially from a common inlet, including a valve body providing said spaced outlets in longitudinally spaced relation to one another and an interior chamber communicating therewith and selectively supplied with pressure iiuid through said inlet, said inlet being nearer said second outlet, a passage in said body connecting said chamber to said second outlet, valve plate means occupying normally a seated position in said body in which it disposes transversely across said chamber, said chamber having an upper portion above said valve plate means communicating with said rst outlet and a lower portion below said valve plate means communicating with said inlet and through said passage with said second outlet, said valve plate means in a seated .position in said body closing said passage to deny flow from the lower portion of said chamber to said second outlet, pressure iiuid in said lower part of said chamber when admitted by way of said inlet tending to lift said valve plate means to an open position relative to said passage, said valve plate means having an opening therein for access of pressure fluid therethrough to the chamber portion above said valve plate means and thereby to said rst outlet, an actuating stem disposed longitudinally in said body and having a valve thereon, said stem being biased in a direction to position said valve in a closing relation to the opening in said valve plate means and being actuatable from outside the body in an extending motion positioning said valve in an open relation to said opening, and means on said stern utilizing extending motion as described to apply holding pressure to said valve plate means to maintain it in seated position while pressure uid is admitted to the lower portion of said chamber and ows through said opening to the upper portion thereof to said first outlet, a retracting motion of said stem releasing said holding pressure and reclosing the opening through said valve plate means whereby ow to said rst outlet is shut oft' while continued supply of pressure fluid to said lower portion of said chamber unseats said valve plate means and opens flow to said second outlet.

17. A valve according to claim 16, characterized by other means on said stem controlling said inlet and opening and closing said inlet on extending and retracting motions of said stern respectively.

References Cited UNITED STATES PATENTS 1,225,987 5/1917 McNeil 251--51 X 3,183,933 5/1965 Whitlock et al. IS7- 624.18

WILLIAM F. ODEA, Primary Examiner.

D. R. MATTHEWS, Assistant Examiner.

Claims

4. AN AUTOMATIC SEQUENCE VALVE, INCLUDING A BODY HAVING A PRESSURE FLUID INLET AND FIRST AND SECOND OUTLETS, SAID OUTLETS BEING IN PARALLEL RELATION TO ONE ANOTHER, SAID BODY DEFINING A VALVE SEAT INTERMEDIATE SAID INLET AND SAID OUTLETS AND OPPOSITE SAID SEAT A CLOSED CYLINDRICAL CHAMBER, A PISTON VALVE RECEIVED IN SAID CHAMBER AND MOVABLE IN OPPOSITE DIRECTIONS THEREIN TO ENGAGE AND BE DISENGAGED FROM SAID SEAT TO DENY AND TO ALLOW FLOW OF PRESSURE FLUID FROM SAID INLET TO SAID OUTLETS, A STEM RECIPROCABLE IN SAID BODY AND CONNECTED TO SAID PISTON VALVE FOR OPERATION THEREOF, ANOTHER VALVE OPERABLE BY SAID STEM DURING PORTIONS OF THE MOVEMENT OF SAID PISTON VALVE TO OPEN AND CLOSE FLOW TO ONE OF SAID OUTLETS, SAID STEM OPENING SAID PISTON VALVE AND SAID OTHER VALVE DURING MOTION IN ONE SENSE AND CLOSING SAID PISTON VALVE AND SAID OTHER VALVE DURING MOTION IN AN OPPOSED SENSE, AND MEANS INTERPOSING A TIME DELAY IN THE MOTION OF SAID STEM IN A DIRECTION TO ENGAGE SAID PISTON VALVE WITH SAID SEAT.