US3373763A

US3373763A - High speed valves

Info

Publication number: US3373763A
Application number: US253779A
Authority: US
Inventors: Smilges Robert; Joseph H Caslow
Original assignee: American Brake Shoe Co
Current assignee: American Brake Shoe Co
Priority date: 1963-01-04
Filing date: 1963-01-04
Publication date: 1968-03-19
Anticipated expiration: 1985-03-19

Description

March 19, 1968 R. sM|| GEs ET AL HIGH SPEED VALVES Filed Jan. 4, 1963 es 60 7| 6| es e4 5| 3 Sheets-Sheet l 7| llO |07 lll 65 |06 6o H2 5| 54 s 74 56 67 |05 MQ g?, r 9% 52o 34 nl m .W 44 |oo |04 \37 I| v 3o :73 35 |03 lol |02 Iig... E' v INVENTORS.

JOSEPH H. CASLOW ROBERT SMILGES OD,4 HERRON 8 EVANS March 19, 1968 R, SMlLGEs ET AL y 3,373,763

HIGH SPEED VALVES Filed Jan. 4, 1963 5 Sheets-Sheet 2 INVENTORS.

JOSEPH Hp CASLOW ROBERT sM/LGES f .F.zg.. .ZJ BY wooo, HERRoNa EVANS March 19, 1968 RSMILGES vFTM l 3,373,763

HIGH SPEED VALVES Filed Jan. 4, 1963 3 Sheets-Sheet 3 INVENTORS ROBERT SM/LGES JOSEPH H CASLOW BY WOOD, HERRON EVANS A 7' TOENE YS United States Patent C) 3,373,763 HIGH SPEED VALVES Robert Smlges and Joseph H. Caslow, Columbus, Ohio, assignors to American Brake Shoe' Company, New York, N.Y., a corporation of Delaware Continuation-impart of application Ser. No. 102,824, Apr. 13, 1961. This application Jan. 4, 1963, Ser. No.

20 Claims. (Cl. 137-269) pending application Ser, No. 102,824, tiled Apr. 13, 1961,

and since abandoned.

A principal objective of the present invention has been to provide a valve construction which is capable of high speed response to changes from a predetermined hydraulic condition, but which is also adapted to be manufactured at minimum cost in a wide variety of sizes. Prior to the present invention, complete hydraulic valves of various sizes for each predetermined type of service have been manufactured. Each such valve has had a multiplicity of parts some of which may be identical in function to similar parts of other 4valves of different flow capacities or of different pressure capabilities. Though of like function in their respective valves, similar parts of such valves have differed appreciably in size. For example, a hydraulic system in which uid flows in relatively small volume may be served by, say, 3A inch valve, whereas another system intended to operate at the same pressure may include a large hydraulic motor for which a two inch valve is required in order to carry the volume of uid needed for proper operation of the large motor; the two valves may thus be comparable in pressure rating but differ as to size, It is apparent that the valve manufacturer has not only had to maintain a large inventory of complete valves of different sizes but has also had to manufacture a wide variety of sizes of the parts needed for the assembly of each type of valve in the different size ranges. On this account, it is not practical to use the most economical types of high production tooling suited for large quantity runs.

The present invention contemplates a series of valves of different sizes, types and hydraulic functions, which are uniform from valve to valve as to the hydraulic control members which the valves contain, such that the critical elements which must be precisely machined, i.e., the movable valve members and associated parts, may be manufactured with the greatest economy in large production runs. According to the invention, different valves in the series are characterized in that the bodies thereof, including inlet and outlet ports, differ from valve to valve according to the ow requirements, pressure ratings, and type of mounting in the systems in which the valves are to be installed, but also in that the valve bodies contain chambers which are uniform in size from valve to valve regardless of body construction. Such chambers communicate with the inlet and outlet ports of the bodies and contain the main movable valve elements through which valve opening or closing is effected, which valve elements are likewise uniformly sized. Eachvalve body also contains one or more fluid passageways terminating in a face which is adapted to receive a cap assembly containing pressure responsive elements through which opening and closing of the main valve members in the chamber of the body is determined to effect various control functions, and

ICC

such cap elements are usable with all of the valve bodies of the series regardless of their individual characteristics. By this means it is apparent that a valve manufacturer is enabled to establish large production runs on pieces of uniform size and thereby eliminate the inefficiency involved in short production runs of a Wide variety of pieces.

In order to enable these concepts of economy to be utilized, however, it isessential that valve structure be provided in which the valve element serving the inlet and outlet ports of the largest valve in the series will respond uniformly and satisfactorily when controlling much' lower flow ratesor much lower pressures or both. Heretofore, the reason the various operating parts of valves have been proportioned in size according to the service requirements the valves were expected to meet has been that a valve structure suitable for handling large volumes of fluid at high pressure would not be equally capable of serving much smaller volumes of Huid or fluid at much'lower pressure or vice versa.

Thus, a second important aspect of this invention is a valve structure which, without variation in the size of its main operating elements, has been found to display the ability to respond uniformly and reliably to widely different ow rates and pressures. More specifically, thisinvention is predicated in part upon a valve construction in which a high rate of response is obtained upon variation of pressure from a predetermined condition whether the flow rate or pressure is large or small. According to this invention, the chambersof all the valve bodies of the series, and the main valve members contained in such' chambers, are suiciently large to accommodate the maximum flow and pressure expected of the largest valve of the series, but are so constructedA that lthey are equally capable of accommodating the smal-lest flow at the lowest pressure expected to be served by the smallest valve of the series.

In more particular detail, the objective of this invention has been to provide a valve having a chamber communicatingvwith inlet and outlet ports, a valve member movable in the chamber and having an endwise portion` forming a closure with the inlet port for limiting escape of fluid from the outlet port thereof, but also movable to open position in response to variation of pressure from some predetermined pressure. The valve member is biased to closed position when the predetermined pressure conditiony exists,

but is maintained in hydraulic balance by pressure exerted at the end thereof opposite the seating end, through uid admitted thereto through a passage. The relief of uid pressure from this end of the valve is provided by control elements responsive to pressure, which elements are contained in a cap, as subsequently described. The invention thus provides a valve capable of being used within a wide range of requirements, and this characteristic, in turn, enables a level of standardization ofl manufacture which has not heretofore been possible.

The Ivalve members of a valve in accord-ance with this invention are so contgurated that in open position, the' movable Valve member is in substantial hydraulic balance but in closed position presents an area to closing pressure slightly exceeding, preferably by about 0.5% to about 6% or more, the area` which it then presents to opening pressure. The movable valve member is preferably in the form of a cylinder having a conical taper at its seating end, the taper forming anangle greater than about 10 and less than about 30' with the axis of the cylinder.

Another objective of this invention has been the provision of optional means in the valve for preventing the valve from opening inresponse to an excess of pressure at its outlet port with respect to its inlet port, whereby 3 the valve is adapted for use in systems wherein the valve is subjected to reversed pressure conditions.

Valves constructed in accordance with the foregoing principles are illustrated in the accompanying drawings in which:

FIGURE 1 isa vertical cross-section of a 5,000 p.s.i. 3r-inch relief valve embodying the principles of the invention, including a body adapted to be subplate mounted, closure-forming members received by a chamber in the body, and a cap which is mounted to the body and which contains a pilot valve whereby the main closureforming members are caused to release or relieve pressure in excess of a predetermined value;

FIGURE 2 is a vertical cross-section of the body of a 5,000 p.s.i. 3%; -inch threaded valve which is adapted for use with the `cap and closure-forming members shown in FIGURE 1;

FIGURE 3 is a vertical cross-section of the body of a 5,000 p.s.i. 2-inch flange mounted valve which is adapted for use with the cap and closure-forming members shown in FIGURE 1;

FIGURE 4 is a vertical cross-section of the body of a 5,000 p.s.i. 2-inch subplate mounted valve which is adapted for use with the cap and closure-forming members shown in FIGURE 1;

FIGURE 5 is a vertical cross-section of a 5,000 p.s.i. M1-inch sequence valve including a body adapted to be subplate mounted, closure-forming members similar to those shown in FIGURE 1, and a cap structure which is generally similar to that of FIGURE 1 but which is modified to cause the main closure-forming members to open at a predetermined pressure and direct flow at substantially that pressure to an outlet;

l FIGURE 6 is a vertical cross-section of a 5,000 p.s.i. ll/z-inch unloader valve including a body adapted to be subplate mounted, closure-forming members similar to those shown in FIGURES 1 and 5, and a cap structure mounted to the body which contains a pilot valve where- Iby the main closure-forming members are caused to open at a predetermined control pressure which is independent of the pressure acting on the main closure members;

FIGURE 7 is a vertical cross-section of a 3,000 p.s.i. %inch relief valve including a body adapted to be subplate mounted, closure-forming members of the type shown in FIGURES 1, 5 and 6 which are received in a chamber formed in the body, and a cap structure mounted to the body which contains a pilot valve whereby the main closure members are caused to relieve pressure in excess of a predetermined value;

FIGURE 8 is a vertical cross-section of the body of a 3,000 p.s.i. M1-inch threaded valve which is adapted for use with the cap and closure-forming members shown in FIGURE 7;

FIGURE 9 is a vertical cross-section of the body of a 3,000 p.s.i. ll/z-inch subplate mounted valve which is adapted for use with the cap and closure-forming members shown in FIGURE '7;

FIGURE l0 is a lVertical cross-section of the body of a 3,000 p.s.i. ll/z-inch threaded valve which is adapted for use with the cap and closure-forming members shown in FIGURE 7;

FIGURE 11 is ayvertical cross-section taken on line 11-11 of FIGURE 10;

FIGURE 12 is an enlarged cross-section of a portion of the main closure-forming elements illustrating a preferred construction thereof in accordance with the invention; and

FIGURE 13 is a vertical cross-section of a relief valve embodying the principles of the invention and including novel check valve means incorporated in a sandwich plate between the valve body and cap, whereby the valve is prevented from opening in response to an excess of pressure at its normal outlet port.

All of the valve bodies illustrated in FIGURES l-ll receive main closure-forming elements of the type shown 4 in FIGURE 1 and described more fully hereinafter, whereby those elements can be used in valves of various pressure ratings, ow capacities, and mountings. Moreover, these valve bodies may be fitted with any of several different cap structures to provide, with slight modification of the body, various control functions.

For example, the valve bodies illustrated in FIGURES 1-6 are capable of handling pressures up to 5,000 p.s.i., while the valve bodies shown in FIGURES 7-11 are capable of handling lesser pressures up to 3,000 p.s.i. The bodies of FIGURES 1, 2, 5, 7, and 8 are for use with 3A- inch piping, the bodies of FIGURES 6, 9, l0 and ll are for use with ll/z-inch piping, while FIGURES 3 and 4 illustrate valve bodies for use with two inch piping. Various types of mounts are illustrated, the valve bodies of FIGURES 1, 4, 5, 6, 7, and 9 being adapted for mounting to a conventional subplate, those of FIGURES 2, 8, 10 and 1l being adapted to receive threaded piping, while the valve body shown in FIGURE 3 is for ange mounting. The cap structures shown in FIGURES 1 and 7 provide relief valve control function, while the cap structures shown in FIGURES 5 yand 6 respectively provide sequence and unloader control functions. As previously explained, by reason of this inter-changeability of parts the valve manufacturer is enabled to supply a series of valves for different requirements by producing relatively few components.

In FIGURE l, a relief valve is shown which includes a body 20 having an internal chamber 21 in the form of a central downwardly extending bore. Chamber 21 cornmunicates coaxially at its lower end with an inlet port 22, and communicates laterally with an outlet port 23. Outlet port 23 curves downwardly from chamber 21 and extends to the flat lower face 24 of body 20 at a position spaced from inlet port 22. A vertical passage 25 extends between the lower face 24 and the upper face 26 of body 20, and communicates with inlet port 22 through a transverse passage 27. This passage 27 is closed at its outer end by a plug 30, and is provided with a reduced orifice 31 between vertical passage 2S and inlet port 22. The flat lower surface 24 of body 20, which inlet port 22, outlet port 23 and vertical passage 25 meet at spaced positions, is adapted to be tted to a standard subplate mount provided on hydraulic equipment or piping, fluid seals being provided by appropriate means such as the O-rings shown.

A cylindrical groove 32 is formed in chamber 21 adjacent outlet port 23. A sleeve 33 is fitted into chamber 21 and is held therein by the cap structure to be described. This sleeve 33 is provided with an internal groove 34 from the lower wall of which a seat 35 having the form of a right angular shoulder extends inwardly adjacent inlet port 22. Groove 34 in sleeve 33 communicates with groove 32 of chamber 21 through spaced ports 36. The internal angular edge of the shoulder presented by seat 35 cooperates in line contact with a movable poppet or piston 37 more fully described hereinafter to form a valve between inlet port 22 and groove 34. Groove 34 in turn communicates through ports 36 to outlet port 23.

Cylindrical poppet 37 is slidably received within sleeve 33. Poppet 37 is provided with a downwardly extending bore 40, and a plug 41 is threaded into an opening at the lower end of poppet 37. As is best shown in FIGURE 12, the peripheral lower edge 42 of poppet 37 is conically tapered or angulated, preferably at an angle of about 10 to about 30 with respect to the axis of the poppet. An angle of about 20 is most advantageous. This angulated surface 42 cooperates in line contact with the edge of seat 35 to from a valve.

Spaced circumferential grooves 43 are formed around the upper portion of poppet 37 to form a sliding seal with sleeve 37. A low-rate spring 44 is disposed in the internal chamber 45 within poppet 37 and urges the poppet toward the position shown, in which surface 42 bears upon seat 35 in line contact therewith. Spring 44 may, by way of example, urge poppet 37 toward closed position with a force in. the range of 30 to 50 pounds, although this is not critical..

We have empirically determined that the operation of the valve is substantially improved, particularly in respect to reduction of leakage, if the cross-sectional area of poppet 37 is about 0.5% to about 6% greater than the internal area within the edge of seat 35. Otherwise put, the operation of the valve is improved if when the valve is closed the downwardly acting force of hydraulic fluid in chamber 45 within sleeve 33 above the poppet is slightly greater than the upwardly-acting force of fluid at like pressure on the lower fact of poppet 37, whereby a slight net closing force will then exist. When

valve

35, 42 is open, however, the upwardly and downwardly facing areas of poppet 37 exposed to pressure will be equal, so that the poppet will then be in substantial hydraulic balance.

Because of the relatively large line of contact of poppet face 42 with seat 35, slight upward axial motion of the poppet presents a relatively large orifice area through which fluid can pass. The poppet travel required to pass a large flow of fluid is not much greater than that required to pass a small flow, whereby valve response is substantially similar regardless of flow. Tests have confirmed that valves embodying this construction are substantially immune to variation in response with velocity change and, moreover, do not evidence wire drawing.

By reason of the differential of the valve area subjected to closing pressure over the area subjected to opening pressure when the valve is closed, a net fluid force acts to hold the valve closed, in addition to the force of spring 44, and this force increases with the pressure tending to open the valve. Thus, the greater the opening pressure, the more tightly the valve is held closed, so that leakage at high pressures is reduced. At low pressures, however, the force tending to hold the valve closed is also low so that no large unbalanced forces are applied to the edge of seat 35. When the valve is open, the areas subjected to opposing pressures are equal, the valve is in hydraulic balance, and is `biased only by spring 44, so that it can readily respond to pressure changes.

We have also found that a taper angle of more than about and less than about 30 contributes to the feasibility of using a standard size poppet and sleeve in a range of valve bodies. Tests have shown that with an angle of about 10, the poppet travel required for full flow is too great to permit satisfactory use of the poppet in a valve of large flow capacity. On the other hand, an angle of about 30 tends to cause valve chatter at high pressures. We prefer that the angle be about at which the standard poppet and sleeve perform well in all of the various bodies to be described.

A cap 50 containing structure which comprises a pilot valve is mounted to the upper face 26 of body 20 by means of screws not shown and closes the open upper end of chamber 21. Cap 50 has a horizontal bore 51 formed in it which is closed at one end by a plug 52. Vertical passage of body 20 communicates with bore 51 through a bore 53. Another vertical passage or bore 54 extends between the upper end of chamber 21 and bore 51 in the cap, and includes a restricted orifice insert 55. Another vertical passage 56 communicates from bore 51 to a bore 57 in body 20 which in turn communicates with outlet port 23. Fluid seals between body 20 and cap 50 are provided at all of these passageways by means of suitable gaskets such as the O-rings shown.

Between bores 53 and 54 in bore 51 there is disiposed a sleeve 60 and a guide bushing 61 which contains a reciprocable piston 62. A pilot valve seat 63 is fitted into bore 51 against a step or shoulder therein. Valve seat 63 is engaged by conical valve element 64 which is urged toward seat 63 by a coil spring 65 disposed between valve element 64 and a spring adjustment screw 66 which is threaded into a` collar 67 secured to cap 50 at the end of bore 51.

The piston 62 received in guide bushing 61 serves in the operation of

valve

63, 64 to assist in moving valve element 64 away from seat 63. This piston 62 has a restricted passage 70 formed therethrough to establish limited communication between section 71 of bore 51 which is to the left of bushing 61, and section 72 of bore 51 which is between bushing 61 and seat 63. The restricted passage 70 in piston 62 also provides for a pressure drop between opposite ends of the piston when fluid is permitted to flow past valve element 64. The right end of bushing 61 is reduced so that bore 54 communicates with section 72 of bore S1.

When fluid pressure is applied to the lower face 73 of poppet 37 at inlet port 22, some of this fluid will flow in transverse passage 27 through orifice 31 into vertical passage 25 and communicating passage 53 into section 71 of bore 51 which is to the left of guide bushing 61. Some of this fluid flows through restricted passage 70 in piston 62 to section 72 of bore 51 between guide bushing 61 and seat 63, and through vertical passageway 54 and orifice 55 into the chamber 45 above the lower end of poppet 37. This fluid is substantially at the pressure of fluid at inlet port 22. The unbalance of opposing hydraulic forces due to the difference in poppet areas acted on by fluid pressure, together with the downward force of spring 44, maintains

valve

35, 42 closed.

As the pressure in the system increases, it tends increasingly to force valve element 64 away from seat 63 against the counteracting force of spring 65. When the pressure becomes so high that the fluid forces acting on valve element 64 at seat 63 overcomes the preadjusted force of spring 65, valve element 64 is pushed slightly away from the seat 63, and fluid flows from the space 72 in bore 51 between guide bushing 61 and seat 63 to the section 74 on the other side of seat 63, from which it is exhausted through bores 56 and S7 to outlet port 23, which in a typical system would be connected to a fluid reservoir or tank. The flow of fluid through restricted bore 70 in piston 62 causes a differential in pressure between the ends of piston 62 to be established. In response to the differential in pressures acting on its end faces, piston 62 is moved toward seat 63 forcing valve element 64 still further from the seat, so that an outlet is thereby provided for fluid in chamber 45 above the lower end of poppet 37. As this pressure is released, the now relatively high fluid pressure at the lower end 73 of poppet 37 rapidly moves the poppet upwardly, whereby

valve

35, 42 is opened and the pressure at inlet port 22 is released.

When the fluid pressure in chamber 71 drops sufficiently the force tending to move piston 62 and valve element 64 to open position will be reduced to a point at which spring 65 can force valve element 64 back into engagement with seat 63. This action will close the outlet from chamber 45, and the fluid pressure therein will quickly build up to the same pressure obtaining below poppet 37 at inlet port 22. As these pressures approach equalization, spring `44 and fluid pressure in chamber 45 will cause the poppet to move downwardly to effect the closure of

valve

35, 42.

It will be seen from the foregoing that the precise pressure at which

valve

35, 42 opens to relieve pressure at inlet port 22 is determined by the force applied through spring 65 to valve element 64. This force is determined by the compression of the spring, which may be regulated by adjusting screw 66 in collar 67.

In FIGURE 2 there is shown a valve body 68 which differs from the valve body 20 shown in FIGURE l in that the valve body 68 shown in FIGURE 2 is adapted to receive threaded piping. Apart from the difference in the type of interconnection to hydraulic equipment for which it is adapted, however, the valve body lshown in FIGURE 2 is generally similar to the valve body shown in FIGURE l, and includes an inlet port 74 which cornmunicates with a chamber 75, a lateral outlet port 76, a transverse bore 77 and

vertical bores

80 and 81 which communicate from the flat upper face 82 of body 68 to transverse bore 77 and chamber 75 respectively.

Chamber 75 is provided with a groove 83 which corresponds with groove 32 of body 20 shown in FIGURE 1, and is adapted to receive a sleeve and poppet assembly similar to those designated by 33 and 37 respectivelyv in FIGURE 1. Body 68 is adapted to receive the cap 50 shown in FIGURE l or the caps shown in FIGURES and 6 which are described more fully hereinafter, bores 80 and 81 and chamber 75 of body 68 being so spaced as to communicate with the

bores

53, 54 and 56 of cap 50 when the cap is mounted to the body. The valve body 63 shown in FIGURE 2 makes it possible, in effect, to convert the subplate mounted relief valve of FIGURE 1 into a threaded relief valve simply by inserting the sleeve 33 and poppet 37 in chamber 75, mounting the cap on the upper surface 82 of the body, and inserting an orice and plug corresponding to orifice 31 and plug 30 of FIGURE 1 into the body.

FIGURE 3 illustrates another type of valve body which is adapted for flange mounting to hydraulic pipe and which is adapted to receive the same sleeve and poppet shown in FIGURE 1 and a cap such as shown in FIG- URES 1, 5 and 6. Whereas the valve bodies shown in FIGURES 1 and 2 are for use with 3pinch pipe, however, the valve bodies of FIGURES 3 and 4 are adapted for use with two inch pipe, even though they will receive the same sleeve, poppet, and caps as valves of smaller capacity. This interchangeability of parts in valves of different capacities is possible because the sleeve and poppet shown in FIGURE 1 are just as effective in their ability to handle the larger flows delivered by two inch pipe, for example, as they are in controlling the smaller flows delivered by 11/2 and %inch pipe. Specifically, valve response to sudden pressure increases or decreases is substantially similar regardless of the flow passing through the valve.

In FIGURE 5 there is shown a valve generally similar to the valve shown in FIGURE 1 in overall construction, but which is adapted to function as a sequence valve through minor changes in `the cap structure. The body, sleeve and poppet of this valve are the same as those shown in FIGURE 1, but passage 70 of piston 62 is closed by a plug 90, bore 56 is closed by a plug 91, and horizontal bore 51 is provided with an outlet 92 which, in operation of the valve, Would normally be connected to tank. Transverse or radial inlets 79 are formed in piston 62 adjacent to plugged left end thereof, opening inwardly into passage 70.

The valve of FIGURE 5 is adapted to function as a sequence valve which will open at a specific inlet port pressure to direct liow to the outlet port at that pressure. In the operation of the valve, fluid pressure at inlet port 22 is applied to the underside 73 of poppet 37 and, through bore 27, orifice 31, passage 25, bore 53, and the transverse inlets 79 into passage 70, to the end of conical valve element 64. When inlet pressure rises to that point at which the force applied to the conical valve element 64 overcomes the force of spring 65, valve element 64 is moved laway from seat 63 and the piston 62 follows the movement of element 64 and the transverse inlets 79 to passage 70 in piston 62 are closed by the guide bushing 61 whereupon the pressure acting upon the closed end 90 assumes control of element 64 and holds it olif its seat 63. When this occurs, pressure in chamber 45 above poppet 37 quickly drops. The balance of forces acting on poppet 37 then causes the

valve

37, 42 to open, so that liuid flows without substantial pressure drop to outlet port 23. When pressure acting on the plugged end 90 of piston 62 drops below a value determined by the compression of spring 65, the piston 62 is moved to the left by spring 65 and opens the transverse inlets 79 to passage 70 whereby pressure inside of spool 37 in chamber 45 rapidly rises due to flow through orifice 31,

passages

25 and 53, section 71 of bore 51, passage 70 in piston 62, and orifice 55, until it equals inlet pressure. Spring 44 then causes valve 42, to close. The relief valve of FIGURE 1 thus may be converted into a sequence valve simply by mounting a cap of the type shown in FIGURE 5 on the body 20. This cap may alternatively be used on any of the other bodies shown inFIGURES 1-6 to provide a sequence control function.

The valve shown in FIGURE 6 is an unloader valve which opens to release pressure at its inlet port when a control pressure, which may be different than the inlet pressure, exceeds a predetermined value. This valve includes a body which receives the same main valve elements as the submount valve body 20 shown in FIG- URES 1 and 5, but which is adapted for use with 1v1/2 inch pipe. Specifically, both inlet port 101 and outlet port 102 are larger than the corresponding

ports

22 and 23 of the valve shown in FIGURE 5, and the 'body is designed to withstand the greater forces to which it is subjected under the greater volume of fluid it handles.

A plug 103 fitted into bore 104 isolates vertical pas sage 105 from inlet port 101. The valve cap 106 differs from the cap structure 50 shown in FIGURE 1 in that the piston 107 mounted by guide bushing 110 is solid, and in that the movable valve element comprises a free spherical ball 111 which is centered by a spring-loaded member 112. The section of bore 51 between guide bushing 110 seat 63 communicates with chamber 45 above poppet 37 through orifice 5S, and the chamber 74 to the right of seat 63 communicates with outlet bore 57 through bore 56.

The operation of the unloading valve is as follows: when the control pressure applied to the left end of piston 107 through vertical passage 105 is low, spring 65 holds ball valve 111 against seat 63. The pressure below poppet 37 is refiected in chamber 45 above poppet 37 through orifice 113, spring 44 holding poppet 37 in closing relation with seat 35. When the control pressure becomes great enough to cause piston 107 to push ball 111 away from seat 63, the pressure above poppet 37 quickly drops, causing the valve 35, 4Z to open. The valve remains in open position as long as the control pressure in chamber 71 is high enough to hold pilot valve 63, 111 open, regardless of the pressure at inlet port 101. When the pressure of fluid in chamber 71 is insufficient to overcome the force of spring 65, valve 63, 111 is closed, and the pressure in chamber 45 above poppet 37 rapidly builds up through orifice 113 until it substantially equals the pressure at inlet port 101, whereupon spring 44 closes

valve

35, 42.

In FIGURES 7 through ll there are shown several valves and valve bodies embodying the principles of the invention but which differ from the valves and valve bodies shown in FIGURES 1 through 6 in that they are designed to operate at pressures up to only 3,000 p.s.i. In each instance the various valve bodies are designed to accommodate the standard sleeve 33 and poppet 37 but are somewhat less heavily constructed at critical points as the uid forces to which they are subjected are not as great.

The cap of the valve shown in FIGURE 7 includes pilot valve structure whereby the

valve

35, 42 is caused to function as a relief valve. This cap valve structure differs from that of FIGURES l, 5 and 6 in that it does not include a push-off piston. Fluid pressure below poppet 37 is applied through orifice 92 to chamber 45 above poppet 37, spring 44 holding the poppet in contact with seat 35. Fluid at this same pressure is also applied through orifice 121 to the left end of valve element 64 tending to urge that element away from its seat 63. When the fluid pressure rises to a point such that the hydraulic force tending to open

valve

63, 64 exceeds the force of spring 65, which is determined by the setting of adjusting screw 66, valve element 64 is moved away from its seat 63, so that the pressure above poppet 37 drops, since chamber 74 to the right of seat 63 is connected to outlet port 23 through communicating

passages

122 and 123 in the valve cap and body respectively. Flow from inlet port 124 through orifice 92 tending to reduce the low 9 pressure in chamber 45 is restricted by the narrow size of orifice 92, and the

valve

35, 42 remains open as long as the force exerted by fluid in chamber 125 on valve element 64 is greater than the force of spring 65. The valve remains in this condition until pressure applied at inlet port 124 drops below a predetermined value.

In FIGURES 8-11 are illustrated various types of valve bodies capable of lhanding pressures up to 3000 p.s.i. at various flow rates when fitted with standard

closure forming members

33, 37 and a cap 120 such as that shown in FIGURE 7. It will be appreciated that the cap 120 can be modified to provide a sequence or unloader control function by modification as above described in connection with FIGURES and 6. High speed response is achieved in all these valves.

By reason of the previously described difference in the areas of poppet 37 which are acted upon by opposing pressures when the valve is closed, it is possible that if the pressure at outlet port 23 should exceed the pressure at inlet port 22, a valve of the type shown in FIGURE 1 might open and permit reverse flow. This may be explained by a specific illustration- If the force of spring 44 is about 50 pounds, and if the differential in areas is about 3%, and further if the cross-sectional area of the spool is one square inch, then an excess of pressure at outlet port 23 over the pressure at inlet port 22 will act upwardly on an area of .03 square inch. If the pressure at port 22 is atmospheric pressure and the pressure at port 23 is about 1670' pounds, then the unbalanced opening pressure will be in excess of 5() pounds and will exceed the closing force of 50 pounds applied by the spring, causing the valve to open.

For this reason, if the valve is to be used in a circuit in which it is likely to be subjected to reversed pressure conditions, that is, conditions in which pressure at port 23 which is greater than the pressure at port 22, we

prefer to use a valve wherein the area difference is of the order of about 0.541%. When the area differential is in this range, the unbalanced pressure at port 23 tending to open the valve will not supply a very large force in relation to the force of spring 44. Actual tests have demonstrated that at pressures up to about 5000 p.s.i. the valve will not open where the area differential is about .67%. Those skilled in the art will realize that similar results might also be effected yby using a spring 44 of greater force, but that is undesirable inasmuch as it tends` to make the operation of the valve more sluggish.

FIGURE 13 illustrates a valve in accordance with this invention which includes alternative means in the form of check valves whereby it is adapted for use in a system in which the pressure conditions may become reversed. The check valve means of the valve shown in FIGURE 13 enable any valve in accordance with this invention to be used under reverse pressure conditions, regardless of the area differential of the poppet or of the force of the spring.

In the past it has occasionally been necessary to utilize a separate check valve connected to the outlet port, to permit ow from the outlet port but not toward the outlet port, so that an excess of pressure in the outlet linewould not be reected past the check valve to the poppet to tend to cause the valve to open. However, such check valves necessarily carried the full ow of the valve, and on that account were quite large and bulky and were undesirable where space was at a premium.

The novel check valve means we have invented are very compact, and preferably are iitted as an integral part of the valve in the form a sandwich plate between the upper face 26 of the valve body 20 and the lower surface of cap 50.

FIGURE 13 illustrates a preferred embodiment of a check valve means in accordance with this aspect of our invention. This valve includes a check valve permitting flow from the inlet port to chamber 45 but lnot in the reverse direction, and a second check valve permitting ow 10 from the outlet port to chamber 45, but not in the reverse direction.

The valve body 20 and each of the elements contained therein may conform, for purposes of description, to the valve body previously described in connection with FIG- URE 1, although the principles of this aspect of the invention are not limited to that valve body alone but in fact are also equally applicable to the other valve bodies shown in the other iigures. Similarly, the control cap 50 corresponds to the cap illustrated in FIGURE 1, and enables the valve to function as a relief valve,

The check valves are advantageously contained in a sandwich plate 125, having parallel upper and lower surfaces, which is secured between the cap 50 and valve body 20 by suitable fastening means not shown. A horizontal bore 126 in the cap is intersected at its right end by a vertical bore 127 which communicates with vertical bore 57 of the valve body and with vertical bore 56 of the cap. A second vertical bore 128 intersects horizontal bore 126 of the sandwich plate adjacent its left end, and communicates between vertical passage 25 of the valve body and vertical bore 53 of the cap 50. A third vertical bore 129 in the sandwich plate communicates from bore 54 of the cap to the chamber 45 above spool 37 in the valve body, but this bore 129, which is indicated by dashed lines in FIGURE 13, does not intersect bore 126.

A ball seat element 131 is fitted in bore 128 of the sandwich plate, and this ball seat element includes a downwardly sloping shoulder surface 132 with which a ball 133 coacts to forni a check valve permitting flow from bore 25 to bore 126 but not in the reverse direction.

At the right end of bore 126 a ball seat element 135 is secured. This ball seat element has an axial bore which includes a restrictor or orifice 136. A plug 137 is threaded in bore 126 and bears against the right end of ball seat element holding that element against a shoulder in bore 126. Radial ports 138 extend from the axial bore in ball seat elements 135 to vertical passageway 127. A shoulder surface 140 is formed at the left end of restrictor 136, and a ball 141 coacts with the shoulder surface 140 to form a check valve permitting flow from bore 127 toward bore 128 but not in the reverse direction.

When the pressure at the valve inlet port 22 is greater than the pressure at outlet -port 23, this pressure is reected through restrictor 31, vertical passageway 25, through the open check valve 132, 133 in vertical bore 128, through vertical bore 53 to the pilot valve in the cap, and the pilot valve functions in the previously described manner.

Check valve

140, 141 is closed and prevents flow from bore 126 to the outlet port. When the pressure vat port 22 exceeds the value at which the

pilot valve

63, 64 is set to open, that valve opens and releases the excess fluid to vertical passageways 56,127 and 57, to the low pressure port 23.

When the pressure at the normal outlet port 23 exceeds the pressure at port 22, the pressure is reflected upwardly through

passageways

57 and 127 into bore 126. The

check valve

140, 141 in the sandwich plate permits flow from bore 57 to bore 53 and this pressure is applied through piston 62 to passageways 54 and 129 into chamber 45. Check valve 132, 133 prevents ow from bore 126 to port 22. The iluid in chamber 45 is thus trapped, and cannot be displaced to permit the srpool to lift regardless of the excess of fluid force tending to open the valve.

lOne of the advantages of this construction is that the main flow of the valve does not pass through the check valves in the sandwich plate, thereby enabling check valves of small size to be utilized, in comparison with past arrangements wherein the full ow of the valve under -normal conditions did pass through the check valve.

It is contemplated that the check valve means we have invented may be used alternatively to the valve construction previously described wherein the area dilerential was small enough in relation to the size of the spring that the valve would not tend to Open under expected reverse pressure conditions.

While the preferred embodiment of the invention has been described herein, the invention is not limited to that form alone but includes other modifications and embodiments within the scolpe of the claims which follow.

We claim:

i. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber at one end thereof, an outlet port extending laterally from said chamber, a cylindrical valve member slidably received in said chamber, said valve member having a diameter larger than that of said inlet port and having an endwise portion seating in edge contact against said inlet port, elastic means biasing said valve member toward said inlet port, a restricted tiuid passage communicating between said inlet port and said chamber at the end of said valve member is opposite to said endwise portion, the area of said valve member which is subjected to pressure in said chamber at the end of said valve member opposite to said endwise portion being greater by about 0.5 to about 6 percent than the area of the endwise portion of said valve member which is subjected to pressure at said inlet port when said valve is closed, and a pilot Valve adapted to release pressure in said chamber at the end of said valve member which is opposite to said endwise portion when pressure in said chamber equals a predetermined value.

2. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber axially at one end thereof, said inlet port presenting a sharp annular seating edge, an outlet port extending laterally from said chamber, a cylindrical valve member slidably received in said chamber7 said Valve member having a conically tapered endwise portion seating in line 'Contact against said edge, elastic means biasing said valve member toward said edge, ow restricting passage means reflecting pressure at said inlet port into said chamber at the end of said valve member which is opposite to said endwise portion, the area of said valve member which is subjected to pressure in said said chamber at the end of said valve member opposite to said endwise portion being greater by at least about 0.5 to about 6 percent than the area within said seating edge, and adjustable pilot valve means releasing excess fpressure in said chamber at the end of said valve member which is opposite to said endwise portion when the pressure in said chamber equals a predetermined value, said valve member being in substantial hydraulic balance when said valve member is open and being subjected to a net closing lpressure when closed which is proportional to the pressure at said inlet port.

3. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber at one end thereof and presenting an annular seat, an outlet port extending laterally from said chamber, a cylindrical valve member slidably received in said chamber, said valve member having a first endwise portion seating against said seat of said inlet port and a second endwise portion in said chamber opposite thereto, elastic means biasing said valve member toward said inlet port, a flow restricting uid passage communicating between said inlet port and said second endwise portion of said valve member, the area of said second endwise portion being greater by about 0.5 to about 6 percent than the area of said rst endwise portion of said valve member which is subjected to pressure at said inlet port when said valve is closed, and a pilot valve adapted to release excess fluid Iunder pressure acting on said second endwise portion of said valve mem-ber when pressure at said inlet port equals a predetermined value.

4. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber at one end thereof, said inlet port presenting a sharp annular seating edge, an outlet port extending laterally from said chamber, a cylindrical valve member slidatbly received in said chamber, said valve member having a con'ically tapered endwise portion seating in line contact against said seating edge, said tapered portion forming an angle of more than about 10 and less than about 30 with the axis of said cylindrical valve member, elastic means biasing `said valve member toward said linlet port, a restricted fluid passage communicating between said inlet port and `said chamber at the end of said valve member which is opposite to said endwise po-rtion, the area of said valve member which is subjected to pressure in said chamber at the end of said valve member opposite to vsaid endwise portion being greater by at least about 0.5 to about 6 percent than the area within said seating edge, and adjustable pilot valve means releasing pressure in said chamber at the end of said valve member when said lpressure in said chamber equals a predetermined value.

5. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, .an inlet port entering said chamber at lone end thereof, said inlet port presenting a sharp annular seating edge, an -ou-tlet port extending laterally from said chamber, a cylindrical valve member slidably received in `said chamber, said valve member having a conically `tapered endwise portion seating in line contact against said seating edge, said tapered portion forming an angle of about 20 .with an axis of said cylindrical valve mem-ber, elastic means biasing said va-lve member toward 'said inlet port, a restricted uid passage communicating between said inlet port and said chamber at the end of said Valve member whichis opposi-te to said endwise portion, the area of said valve member which is subjected to pressure in said chamber at the end of said valve member opposite to said endwise portion being greater by at least about 0.5 to about 6 percent than the area within said seating edge, and adjustable pilot valve means releasing pressure in said chamber at the end of said valve member when said pressure in said cham-ber equals a predetermined Value.

`6. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber axially at one end thereof, said inlet po-rt presenting a sharp annular seating edge, an outlet port extending laterally lfrom said chamber, a cylindrical valve member slidably received in said chamber, said valve member having a conically tapered endwise portion seating in line contact against said edge, la spring biasing said valve member toward said edge, a restricted uid passage communicating between said inlet port and said chamber at the end of lsaid valve member which is opposite to said endwise portion, the area of said valve member which is subjected to pressure in said chamber at the end ot .said valve member opposite to said endwise pontion being greater by about 0.5 to 1 percent than the area within said seating edge, and adjustable pilot valve means releasing excess uid under pressure in said chamber at the end of said valve member which is opposite to said endwise portion when the pressure in said chamber equals a predetermined value, said valve member 'being in substantial hydraulic balance when said valve member is open and being subjected when closed lto a net clos-ing fluid force which lis `small in rela-tion -to the force tending to close the valve member and which is proportional to the lpressure at said inlet port, said difference in areas -being insufficient in relation to 'the force of said spring to cause said valve member to open when pressure at said outlet port exceeds the pressure at said inlet port, up to a predetermined pressure at said outlet port.

7. A Valve compris-ing a valve body having a right cylindrical chamber formed therein, a sleeve coaxially received in said chamber, an inlet port entering said chamber at one end thereof, said sleeve presenting an inwardly extending annular seat adjacent said inlet port,

said seat having a right angular seating edge, an outlet port extending laterally from said chamber through said sleeve downstream of but adjacent to said seat, a cylindrical poppet slidably disposed in said sleeve, said poppet having at one end 'thereof a tapered edgewise portion seating in line contact against said edge, the crosssectional area of said poppet being about 0.5 to 1% greater than the internal area within said right angular seating edge of said seat, the angulation of said tapered edgewise portion being about 20 from the axis of said poppet, iiuid pressure at said inlet port tending to open said valve, uid pressure at the end of said poppet which is opposite said seat tending to close said valve, a rst fluid passage including a restricted orifice for statically balancing the fluid pressures acting on the ends of said poppet, spring means biasing said poppet toward said seat, a drain passage, a second iiuid passage communicating between said first passage and said drain passage, said second passage including a pilot valve adapted to open at a predetermined pressure to release the pressure acting on the end of said poppet which is opposite said seat and thereby hydraulically unbalance the uid pressures acting on the ends of said poppet causing said poppet to open, the difference in areas being insuicient in relation to the force of sa-id spring means to cause said poppet to open in response to a high pressure at said outlet port relative to said inlet port up to a predetermined maximum pressure at said outlet port.

8. A hydraulic valve comprising, a body having a chamber formed therein and having inlet and' outlet ports communicating with said chamber, sa-id inlet port providing a seat extending in a plane generally transverse to the axis of the flow of fluid through said inlet port to said chamber, said seat presenting an annular seating edge, a cylindrical valve member movable in said chamber and having a conical taper at one end which is cooperable in line contact with said seat for closure, of said valve, said taper forming an angle more than about and less than about 30 with the axis of said Valve member, said valve member being urged away from said seat by iiuid pressure at said inlet port, means including a restricted passageway for reflecting pressure at said inlet port to the end of said valve member opposite said seat, said valve member `being constructed so as to reside in substantial hydraulic balance in open position with respect to said seat when exposed to the pressure at said inlet port and the pressure reflected through said pas- Sageway, the area of said cylindrical valve member being about 0.5 to about 6% greater than the area within said seating edge whereby said Valve member is in slight hydraulic unbalance when in closed position with respect to said seat, spring means biasing said Valve member to closed posit-ion, and means associated with said valve body for relieving excess pressure of uid in said passageway and thereby relieving excess pressure exerted on said valve member through said passageway when the pressure in said passageway equals a predetermined value, whereby said valve member becomes unbalanced sufriciently to overcome the spring bias thereof for movement of said valve member away from said seat.

9. A valve comprising a valve body having a right cylindrical chamber formed therein, aV sleeve coaxially received in said chamber, an inlet port entering said chamber at one end thereof, said sleeve presenting an inwardly extending annular seat adjacent said inlet port, said seat having a right angular seating edge, an outlet port extending laterally frorn said chamber through said sleeve downstream of but adjacent to said seat, a cylindrical poppet slidably disposed in said sleeve, said poppet having at one end thereof a tapered edgewise portion seating in line contact against said edge, the cross-sectional area of said poppet being about 0.5-6% greater than the internal area within said right angular seating edge of said seat, the angulation of said tapered edgewise portion being about 20 from the axis of said poppet, iluid pressure at said inlet port tending to open said valve, iluid pressure at the end of said poppet which is opposite said seat tending to close said valve, a iirst iiuid passage including a restricted orilice for statically balancing the uid pressures acting on the ends of said poppet, spring means biasing said poppet toward said seat, a drain passage, a second fluid passage communicating between said rst passage and said drain passage, said second passage including a pilot valve adapted to open at a predetermined pressure to release the pressure acting on the end of said poppet which is opposite said seat and thereby hydraulically unbalance the uid pressures acting on the ends of said poppet causing said poppet to open.

10. A valve comprising, a valve body having a right cylindrical chamber formed therein, an inlet port coaxially entering said chamber at one end thereof, an annular valve seat between said inlet port and said chamber, said seat presenting a sharp, angular annular seating edge, an outlet port extending from said chamber adjacent said seating edge, a poppet slidably received in said chamber, said poppet having a conieally tapered peripheral portion at one end seating in line contact with said seating edge, said tapered portion forming an angle of more than about 10 and less than about 30 with the -axis 0f said poppet, the cross-sectional area of said poppet being about 0.5 to about 6% greater than the area within said annular seating edge, said poppet having a restricted fluid passage communicating between its opposite end surfaces, spring means biasing said poppet toward said seat, and a pilot valve actuable at a predetermined pressure to release excess iiuid in said chamber acting on the end of said poppet which is remote from sa-id inlet port, said pilot valve including a seat and a spring-biased valve element for-ming a valve therewith.

11. A valve comprising, a valve body having a right cylindrical chamber formed therein, an inlet port coaxially entering said chamber at one end thereof, an annular valve seat between said inlet port and said chamber, said seat presenting an annular, sharp angular seating edge, an outlet port extending from said chamber adjacent said edge, a cup-shaped poppet slidably received in said chamber, said poppet having at one end a conically tapered peripheral portion seating in line contact with said seating edge, and forming a valve between said inlet port and said outlet port, said tapered portion forming an angle of more than about 10 .and less than about 30 with the axis of said poppet, the opposite end of said poppet being subjected to pressure in said chamber, the cross-sectional area of said poppet being about 0.5 to about 6% greater than the area Vwithin Said annular seating edge, a fluid passage reiiecting pressure at said inlet port to said opposite end of said poppet, and a -pilot valve actuable in response to a predetermined pressure to release excess fluid under pressure acting on said opposite end of said poppet, said pilot valve including a seat and a spring-biased valve element forming a valve therewith.

12. A valve comprising, a valve body having a right cylindrical chamber kformed therein, an inlet port coaxially entering said chamber at one end thereof, an annular valve seat between said inlet port and said chamber, said seat presenting an annular, sharp angular seating edge, an outlet port extending from said chamber adjacent said edge, a cup-shaped poppet slidably received in said chamber, said poppet having at one end a conically tapered peripheral portion seating in line contact with said seating edge and forming a valve between said inlet port and said outlet port, said tapered portion forming an angle of more than about 10 and less than about 30 with the axis of said poppet, the opposite end of said poppet being subjected to pressure in said chamber, the cross-sectional area of said poppet being about 0.5 to about 6% greater than the area within said annular seating edge, a restricted iiuid passage reflecting pressure at said inlet port to said opposite end of said poppet, spring means biasing said poppet toward said edge, and a pilot Valve actuable in response to a predetermined pressure to release excess uid under pressure acting on said opposite end of said poppet, said pilot valve including a seat and a spring-biased valve element forming a valve therewith, said poppet being utilizable in a series of said valve bodies of different sizes all having cylindrical chambers of equal sizes formed therein.

13. A valve comprising, a valve body having a right cylindrical chamber formed therein, an inlet port coaxially entering said chamber at one end thereof, an annular valve seat between said inlet port and said chamber, said seat presenting a sharp, angular annular seating edge, an outlet port extending laterally from said chamber, a poppet slidably received in said chamber, said poppet having a conically tapered endwise portion seating in line contact with said seating edge, said tapered portion forming an angle of more than about 10 and less than about 30 with the axis of said poppet, the cross-sectional area of said poppet being about 0.5 to about 6% greater than the area within said annular seating edge, a restricted fluid passage communicating between said inlet port and said chamber above the end of said poppet which is opposite to said endwise portion, spring means biasing said poppet toward said seat, a pilot valve actuable in response to a predetermined pressure to release excess uid under pressure in said chamber acting on the end of said poppet which is opposite to said endwise portion, said pilot valve including a seat and a spring-biased valve element forming a valve therewith, check valve means permitting flow from said inlet port to said chamber above the end of said poppet which is opposite to said endwise portion but not in the reverse direction, and check valve means permitting ow from said outlet port to said chamber above the end of said poppet which is opposite to said endwise portion but not in the reverse direction.

14. A valve comprising, a valve body, said body presenting a cylindrical chamber therewithin, an inlet port entering said chamber at one end thereof, an outlet port extending laterally from said chamber, a cylindrical valve member slidably received in said chamber, said valve member having an endwise portion seating in peripheral edge contact against said inlet port, elastic means biasing said valve member toward said inlet port, a restricted uid passage communicating between said inlet port and said chamber at the end of said valve member which is opposite to said endwise portion, the area of said valve member which is subjected to pressure in said chamber at the end of said valve member opposite to said endwise portion being greater by about 0.5 to about 6 percent than the area of the endwise portion of said valve member which is subjected to pressure at said inlet port when said valve is closed, a pilot valve adapted to release excess pressure in said chamber at the end of said valve member which is opposite to said endwise portion when pressure in said chamber equals a predetermined value, said pilot valve having an inlet side and an outlet side, ya check valve between said inlet port and the inlet side of said pilot valve permitting flow toward said inlet side but not in the reverse direction, and a passageway including a second check valve communicating between said outlet port and said inlet side, said second check valve permitting iiow toward said inlet side but not in the reverse direction.

15. A valve comprising, la valve body, said body presenting a cylindrical chamber therewithin an inlet port entering said chamber at one end thereof, an outlet port extending laterally from said chamber, a cylindrical valve member slidably received in said chamber, said Valve member having a iirst endwise portion seating in peripheral edge contact against said inlet port and a second endwise portion in said chamber opposite thereto, elastic means biasing said valve member toward said inlet port, a restricted fluid passage communicating between said inlet port and said second endwise portion of said valve member, said passage including check valve means permitting iiow toward said second endwise portion but not away therefrom, the area of said second endwise portion being greater by about `0.5 to about 6 percent than the area of said first endwise portion of said valve member which is subjected to pressure at said inlet port when said valve is closed, a pilot valve adapted to release excess fluid under pressure acting on said second endwise portion of said valve member when pressure at said inlet port equals a predetermined value, and check valve means permitting flow from said outlet port toward said second endwise portion but not in the opposite direction.

16. A valve comprising a v-alve body having a right cylindrical chamber formed therein, a sleeve coaxially received in said chamber, an inlet port entering said chamber at one end thereof, said sleeve presenting an inwardly extending annular sea-t adjacent said inlet port, said seat having a right angular seating edge, an outlet port extending laterally from said chamber through said sleeve `downstream of but adjacent to said seat, a cylindrical poppet slidably disposed in said sleeve, said poppet having at one end thereof a tapered edgewise portion seating in line contact against said edge, the cross-sectional tarea of said poppet being about 0.5-6% greater than the internal area within said right angular seating edge of said seat, the angulation of said tapered edgewise portion being `about 20 from the axis of said poppet, fluid pressure at said inlet port tending to open said valve, fluid pressure at the end of said poppet which is remote from said seat tending to close said valve, a iiow restricting first fluid passage communicating between said inlet port and the end of said poppet which is remote from said seat Ifor statically balancing the fluid pressures acting on the ends of said poppet in response to pressure at said inlet port, said rst passage including a first check valve preventing flow in the direction toward said inlet port, spring means biasing said poppet toward said seat, a pilot valve contained in a cap, said pilot valve having an inlet side and an outlet side, said inlet side communicating with the end of said poppet which is remote from said seat, said `outlet side communieating with said outlet port, said pilot valve being adapted to open at a predetermined pressure to release excess pressure acting on the end of said poppet which is remote from said seat, and a second passage communicating between said outlet port and the inlet side of said pilot valve, said second passage including a second check valve preventing flow toward said outlet port, said irst and second check valves and said second passage being contained in a sandwich plate mounted between said cap and said valve body.

17. A valve comprising, a valve body having a right cylindrical chamber formed therein, a sleeve coaxially received in said chamber, an inlet port entering said chamber at one end thereof, said sleeve presenting an inwardly extending annular seat Aadjacent said inlet port, said seat having a right angular seating edge, an outlet port extending laterally from said chamber through said sleeve downstream of but adjacent to said seat, a cylindrical poppet slidably disposed in said sleeve, said poppet having at one end thereof a tapered edgewise portion seating in line contact against said edge, the cross-sectional area of said poppet being about 0.5-6% greater than the internal area within said right angular seating edge of said seat, the angulation of said tapered edgewise portion being about 20 from the axis of said poppet, fluid pressure at said inlet port tending to open said valve, iiuid pressure at the end of said poppet which is opposite said seat tending to close said valve, a first uid passage including a restricted orifice and a check valve preventing flow toward said inlet port and statically balancing the uid pressures acting on the ends of said poppet in response to pressure at said inlet port, spring means biasing said poppet toward said seat, a pilot valve yhaving an inlet side and an outlet side, said inlet side communicating with the end of said poppet which is remote from said seat, the outlet side of said pilot valve communicating with said outlet port, said pilot valve being adapted to open at a predetermined pressure to release excess pressure at said inlet side, and a second passage communicating between said outlet port and the inlet side of said pilot valve, said second passage including a check valve permitting ow toward said inlet side and preventing flow in the opposite direction.

18. In combination, a series of hydraulic Valve bodies of different sizes, each body presenting -a chamber, the chamber of all of said bodies being equal in size, an inlet port entering said chamber at one end thereof, means defining an annular seat adjacent said inlet port, said seat presenting a sharp angled seating edge the plane of which is perpendicular to the axis of flow through said inlet port, an outlet port extending laterally from said chamber, a cylindrical poppet adapted to be selectively received in the said chamber of each of said bodies, said poppet having a tapered peripheral portion forming a closure in line contact with said edge, said tapered portion forming an angle of between and 30 with the axis of said poppet, the cross-sectional area of said poppet being slightly greater than the area within said seating edge, passage means including a restricted orifice communicating between said inlet port and the end of said poppet which is opposite to said seat, a spring biasing said poppet toward said seat, a supplemental valve control cap adapted to be selectively removably fastened to each body of said series, said cap including a drain port and a passageway communicating between said drain port and the end of said poppet which is opposite to said seat, valve means in said passageway adapted to open at predetermined pressure to release to said drain port the pressure of fluid at the end of said poppet which is opposite to said seat, the bodies of said series and the inlet ports and outlet ports thereof differing in size from body to body whereby the bodies of the series are respectively adapted for installation in hydraulic lines of different sizes, said chamber and poppet being of a size sufiicient to accommodate the highest pressure and ow requirements to be served by the largest body of the series.

19. In combination, a series of hydraulic valve bodies of different pressure ratings and fiow capacities, each body presenting a chamber, the chambers of the bodies of said series being uniform in size, each body also having an inlet port entering said chamber at one end thereof, a cylindrical sleeve adapted to be disposed within the said chamber of each body of said series, said sleeve presenting a seat adjacent said inlet port, said seat residing in a plane which is perpendicular to the axis of ow through said inlet port and presenting an inwardly offset annular seating edge, an outlet port extending laterally from said chamber through said sleeve, a cylindrical poppet slidably received in said sleeve, said poppet having at one end thereof a tapered peripheral edge forming a valve with said seating edge, the angle of said tapered edge being between 10 and 30, the crosssectional area of said poppet being about 0.5-6% greater than the area within said seating edge, uid pressure at said inlet port tending to open said valve, a passage including a restricted orifice communicating between said inlet port and the end of said poppet which is opposite to said inlet port, said poppet when in open position presenting substantially equal areas to pressure at said inlet port and at the end of said poppet which is opposite to said inlet port, a spring biasing said poppet toward said seat, a valve control cap adapted to be fastened to each body of said series, said cap including a relief valve adapted to open when the pressure at the end of said poppet which is opposite to said inlet port exceeds a predetermined value, the bodies of said series and the inlet ports and outlet ports thereof differing in pressure rating and flow capacity whereby the bodies of the series are respectively adapted for installation in hydraulic lines of different flow capacities and pressures, said chamber, poppet and sleeve being sufliciently large to accommodate the highest pressure and flow requirements to be served by the largest body of the series.

`20. A hydraulic Valve comprising a body selected from a series of bodies of different pressure ratings and ow capacities, each body presenting a chamber, an inlet port entering said chamber at one end thereof, a cylindrical sleeve disposed within said chamber, said sleeve including a seat adjacent said inlet port, said seat presenting an inwardly offset annular right angled seating edge, said edge residing in a plane which is perpendicular to the axis of iiow of fluid through said inlet port into said chamber, an outlet port extending laterally from said chamber through said sleeve, a cylindrical poppet slidably received in said sleeve, said poppet having at one end thereof an angulated annular seating surface forming a valve with said seating edge, the angle of said angulated surface being between about 10 and 30, the crosssectional area of said poppet being about 0.5% to 6% greater than the area Within said seating edge, fluid pressure at said inlet port tending to open said valve, said poppet including a restricted passage communicating between its opposite ends, said poppet in open position presenting substantially equal areas to pressure at each end, a spring biasing said poppet toward said seat, a valve control cap removably fastened to said body, said cap including a pressure actuated pilot valve adapted to open when the pressure at the end of said poppet which is opposite to said inlet port exceeds a predetermined value, the bodies of said series and the inlet ports and outlet ports thereof differing in pressure rating and flow capacity from body to body whereby the bodies of the series are respectively adapted for installation in hydraulic lines of different flow capacities and pressures said chamber, poppet and sleeve being suiciently large to accommodate the highest pressure and flow requirements to be served by the largest body of the series.

References Cited UNITED STATES PATENTS 2,366,596 1/1945 Clifton 137-491 2,480,712 8/1949 Carbon 251-43 X 2,724,406 11/ 1955 Murray 137-491 2,747,606 5/1956 Adams 137--489.5 2,661,017 12/1953 Geiger 137-491 2,661,763 12/ 1953 Renick 137-489 2,737,974 3/1956 Renick 137-489 WILLIAM F. ODEA, Primary Examiner.

R. GERARD, Assistant Examiner.

Claims

1. A VALVE COMPRISING, A VALVE BODY, SAID BODY PRESENTING A CYLINDRICAL CHAMBER THEREWITHIN, AN INLET PORT ENTERING SAID CHAMBER AT ONE END THEREOF, AN OUTLET PORT EXTENDING LATERALLY FROM SAID CHAMBER, A CYLINDRICAL VALVE MEMBER SLIDABLY RECEIVED IN SAID CHAMBER, SAID VALVE MEMBER HAVING A DIAMETER LARGER THAN THAT OF SAID INLET PORT AND HAVING AN ENDWISE PORTION SEATING IN EDGE CONTACT AGAINST SAID INLET PORT, ELASTIC MEANS BIASING SAID VALVE MEMBER TOWARD SAID INLET PORT, A RESTRICTED FLUID PASSAGE COMMUNICATING BETWEEN SAID INLET PORT AND SAID CHAMBER AT THE END OF SAID VALVE MEMBER IS OPPOSITE TO SAID ENDWISE PORTION, THE AREA OF SAID VALVE MEMBER