US3358964A

US3358964A - Seat assembly for balanced pressure reducing valve

Info

Publication number: US3358964A
Application number: US418930A
Authority: US
Inventors: Donald M Cohen; Lester J O'brien; Robert F Nordhoff
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-12-16
Filing date: 1964-12-16
Publication date: 1967-12-19
Anticipated expiration: 1984-12-19

Description

2 Sheets-Sheet l Dec. 19, 1967 D. M. COHEN ETAL SEAT ASSEMBLY FOR BALANCED PRESSURE REDUCING VALVE Filed Deo. 16, 1964' nnww .e @l i www, M NQ v MCIBM/M I- x i Hm. 3rd, www5 N\ IFH. W f5@ @wom DE S Dec. 19, 1967 D, M, COHEN ETAL 3,358,964

' SEAT ASSEMBLY Foa BALANCED PRESSURE REDUGING VALVE Filed Dec. 16, 196.4 2 Sheets-Sheet 2 IN VEN TORS, Donald Cohen es fer' J Orz'en,

United States Patent O 3,358,964 SEAT ASSEMBLY FOR BALANCED PRESSURE REDUCING VALVE Donald M. Cohen, Fallston, Md., Lester J. OBrien, South Orange, NJ., and Robert F. Nordhoi, Baltimore, Md.,

assignors to the United States of America as represented by the Secretary of the Army Filed Dec. 16, 1964, Ser. No. 418,930 4- Claims. (Cl. 251-324) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any r-oyalty thereon.

The invention relates to balanced pressure regulating reducing valve of the type which transmit at reduced pressures fluids received at high pressures. More particularly, the invention relates to such a valve which is fluid balanced rather than spring balanced. The Valve is specifically useful in controlling high gas or air pressures required to operate a military flame thrower, but is, -of course, applicable to other uses requiring the control of other fluids under high pressure, particularly gaseous fluids.

Such devices, particularly when used by military personnel for military purposes, as when used as a part of the flame thrower aforesaid, must be exceptionally strong and well made to withstand the necessary rough treatment to which a llame thrower is subjected. It must be light enough so as not to increase the weight of the flame thrower enough to bar its being transported by one person; it must be efficient and reliable in operation under adverse temperature, climatic and weather conditions; and, nally, it must be simple to operate, maintain and repair so that replacement parts may be easily applied by relatively unskilled personnel using simple tools and under adverse light and climatic conditions.

With the foregoing in View, it is an object of the invention to provide an improved balanced, pressure-regulating reducing valve of the class described.

Another object of the invention is to provide in combination with a novel valve and valve seat, novel fluid controlled means for balancing the valve.

A further object of the invention is to provide a novel seat for the valve.

An additional object of the invention is to provide a novel seat for the valve which includes an O-ring providing the seal together with novel means mounting such O-ring and novel means for bleeding trapped air from the seat or mount for the O-ring.

Still a further object of the invention is to provide in combination with the O-ring mount, a novel valve for such mount.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same- FIGURE 1 is a side elevational view of a valve according to the invention;

FIGURE 2 is an enlarged horizontal sectional view taken substantially on the line 2 2 of FIGURE 1;

FIGURE 3 is a fragmentary sectional View in the plane of FIGURE 2, but on a still larger scale and showing the O-rings and vent holes;

FIGURE 4 is an end elevational view of the back up ring employed in the invention; and

FIGURE 5 is a sectional view taken substantially on the line 5-5 of FIGURE 4.

In the drawings wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral designates generally a hollow casing or housing for the `valve which has secured thereto at one side 3,358,964 Patented Dec. 19, 1967 thereof a second smaller housing 11.

Housings

10 and 11 may be permanently secured together or, as shown, may be readily detachably secured together by any suitable means such as the machine screws or the like 12. Housing 10 has a closed back end 13 and an open front end to which may be threadedly attached any suitable tubular fitting outlet nozzle 14 for lconnecting the outlet in the implement with which the valve is to be used, such as a llame thrower (not shown). Fluid under high pressure, such as compressed air is admitted to the interior of the housing 10 through an inlet port 15. Any suitable fitting,

not shown, connects the inlet port 15 to a source of fluid under high pressure.

A cylinder 16 is disposed within the housing 10 and is generally of small diameter but is freely slidable therein by virtue of a belled rear flange 17 and annular pairs of

shoulders

18 and 19, 20. Between each pair of shoulders is provided a seat for an O-ring 21 which seals off two cylindrical spaces 22 and 23 which surround the cylinder 16. A circumferential series of ports 24 extend through the wall of the cylinder 16 between shoulder 19 and the nearest shoulder 18 which define the cylindrical space 22, and provides means for admitted air under high pressure from the inlet port 15 to the interior of the cylinder 16. The belled rear flange 17 of the cylinder 16 has a rear free edge 17 which bears against the closed back end 13 of the housing 10 to provide a space 25 between the latter and a rearwardly facing annular shoulder 26 of the flange 17. The shoulder 26 is pierced with a series of ports 27 which are in open communication with the rearward cylindrical space 23 defined by flange 17 and the rearmost annular shoulder 18. The purpose of this structure will be apparent hereinafter.

The cylinder 16 is held against the closed back end 13 of the housing 10 by a retainer ring 28 which is slidable within the housing 10 and bears against the front end of the cylinder 16. Ring 28 is releasably secured in position by a screw threaded tubular plug 29 which is threaded into its holding position along the internal screw threaded portion 31 of the housing 10 by a screw driver or the like which engages in the cross slots 30 of the plug 29. As best seen in FIGURE 3, the retainer ring 28 includes a rearwardly extending cylindrical iiange 32 which is telescopically overlaps a forwardly directed like tiange 33 formed on the foremost annular shoulder 20. The free edges of the

flanges

32, 33 are prevented from abutting the end edges of the cylinder 16 and retaining ring 28 respectively by a metal back-up ring 34 best seen in FIG- URES 4 and 5.

Back-up ring 34 has a rear face which is formed with integral rearwardly directed and spaced projections 35 which bear against the front edge of the cylinder 16 so as to provide radially directed spaces between such projections. As illustrated, the projections 35 are generally keystone-shaped and are relatively widely spaced. Other shapes and spacings are contemplated. The periphery of the ring 34 is formed with a number of axially extending grooves or notches 36 which correspond to the number of spaces between the projections 35 and the grooves 36 open into the spaces. The inner periphery of ring 34 is formed with a groove 37 which has an arcuate cross section for the reception therein of an O-ring 38. As the O- ring 38 is normally wider than the back-up ring 34, it is squeezed between the adjacent end edges of the retainer ring28 and the cylinder 16. This deforms the ring 28 slightly and forces it into sealing engagement with the back-up ring 34 as well as with the adjacent end edges of the retainer ring 28 and cylinder 16. Any air which is trapped behind the back-up ring 34 is bled off between the axial projections 35 into the grooves 36, around the end edges of theflanges 32, 33v (which do not have an air tight fit) and is vented from the housing through a series of vent holes 39 formed therethrough. The vent holes 39 open into the interior of the housing 10 in alignment with the composite groove formed by the back-upring-spaced ends of the retainer ring 28 and the overlapped

flanges

32, 33. The O-ring seat 38 provides the seal of the balanced valve of the invention and the mount therefor which has just been described is an important feature of the invention.

O-rings normally cannot be used for high pressure seals of this kind because the high pressure will normally roll it out of its seat and blow it downstream, or alternatively, it is ruptured and destroyed. However, in the structure described and shown, the O-ring is clamped under tension so it cannot be flexed or rolled out of the composite groove. By venting it from the rear no air under pressure can get behind it to force it out of its mount or seat particularly because of its seat in the groove 37 of the back-up ring 34. As the O-ring 38 is under three-way tension it has a close lit in the groove 37 and any air in the composite groove can only get behind the back-up ring 34 where it is bled harmlessly outwardly of the same. It follows, therefore, that the mount of the O-ring 38 is capable of withstanding extremely high pressures without damage to or loss of the O-ring.

A piston head 40 is slidable inside the cylinder 16 and includes a rear face 41 and a frusto-conical front face 42. Any suitable means, such as the O-ring 42 shown, may provide a seal between the piston 40 and the cylinder 16. A cylindrical piston skirt 43 extends rearwardly of the piston head 40 and terminates in a radially outwardly directed flange 44 which is disposed in` the space 25 between the closed back end 13 of the housing 10 and the shoulder 26 of the cylinder 16 to provide fixed stops limiting reciprocal movement of the piston in the cylinder. The ange 44 is of a smaller diameter than inner diameter of the ange 17. A valve stem 45 extends forwardly of the piston head 40 axially thereof and integral therewith. The forward end of the stern 45 is enlarged to provide a valve head 46 which includes a frusto-conical rear face 47 which corresponds in size and shape to the front face 42 of the piston head 40 for a purpose to be apparent hereinafter. Valve head 46 has a cylindrical periphery 48 which has a sealing fit with the O-ring 38 when the piston head 40 is retracted to the rearmost position shown in broken lines in FIGURE 2. As will appear, the valve head and piston are normally located in the full line position of FIGURE 2, wherein the valve head 46 is in forwardly spaced relation to its O-ring seat 38 to permit passage of fluid or air under high pressure outwardly of the housing 10 through the outletitting 14. The valve is normally held in this open position by a means now to be described.

The smaller housing 11 has a closed front end 49 with a main cylindrical bore 50 separated from a reduced cylindrical chamber 51 by an annular shoulder 52 adjacent the front end 49. A retainer ring 53 (generally like the ring 28) is seated against the shoulder 52 by a cylinder 56 which is generally similar to the cylinder 16 aforesaid. Ring 53 and the cylinder 56 have opposing flanges 54 and 55 respectively. If desired, anges 54 and 55 may be telescoped like the

corresponding flanges

32, 33 in the housing 10. Annular shoulders 57 and 58 are formed on the periphery of the cylinder 56 and are longitudinally spaced to define a cylindrical space 59 around the cylinder 56. The cylinder wall between the

annular shoulders

57 and 58 is formed with a plurality of ports 60 which provide access to the interior of the cylinder 56. O-rings 61 positioned outwardly axially of the

shoulders

57 and 58 seal off the space 59. The opposite, or rear end, of the cylinder 56 is belled to provide a ange 62 which is engaged by the tubular nut 63 or the like which is threaded in the threaded portion 64 of the housing 11 to secure the assembly in position similarly to the like assembly in the housing 10.

A piston head 65 is slidable in the cylinder 56 and includes a hollow skirt 66 having a flanged free end 67 which fits in the space 67 defined by the ange 62 and the plug 63. An expansive coil spring 68 ts into the skirt 66 and bears on the rear face 69 of the piston head 65. The rear end of the spring 68 is engaged by an adjusting plug 70 which is seated ina hollow recess 70 of the closure plug 71 which is screw threaded into the housing 11. A socket head screw 72, or the like, is threaded through the plug 71 and has a front end which engages the adjusting plug 70 to vary the tension of the spring 68 in a manner readily understood. A lock nut 73 on the adjusting screw 72 holds the same in adjusted positions. Suitable vents 74 may be formed through the threaded rear portion of the housing 11 between the closure plug 71 and the tubular nut 63.

The front face 75 of the piston head 65 is frusto conical in form and has a Valve stern 76 projecting forwardly thereof. A valve head 77 is formed on the front end of the stern 76 and includes a cylindrical periphery 78 which at times has a sealing seat on the O-ring. However, the spring 68 normally loads the piston head 65 and valve head 77 to a forward position wherein the valve `is open as shown. Housing 10 is formed with a port 79 which is aligned with a like port 80 in the housing 11. Port 79 leads from the high pressure space 22 of the housing 1) and port 80 opens into the space 59 of the housing 11. Forwardly of valve head 77, housing 11 is formed with a port 81 which opens from the chamber 51 into an aligned port 82 in the housing 10 which in turn opens into the space 23.

lt should be pointed out that the mechanism contained within the housing 11 is a small capacity pressure reducing valve which serves as a pilot regulator for control of the main-stream high capacity pressure reducing valve contained within housing 10. Both valves operate in the same manner except the valve head 77 (in the pilot regulator) utilizes the force of the spring 68 to regulate its outlet air pressure which in turn serves as the medium for controlling the output from the larger valve head 46.

In operation, high pressure air enters the space 22 in housing 10 through the inlet port 15. Simultaneously, a portion of the high pressure air is by-passed through the

ports

79, 80 and 60 into the cylinder 56 ahead of the front face 75 of the piston 65 and around the normally open valve 77 at a reduced pressure. Such by-passed air proceeds into the chamber 51 and through the ports 81,.

S2 into space 23 in the housing 10. From there it passes through ports 27 around the outer edge of the ange 44 into the space 25 and into the interior of the skirt 43 of the piston 40 where it loads the rear face 41 of the latter in a forward direction which results in the valve 46 being normally in the open position to permit air to pass through the outlet nozzle 14. The by-passed airflow from the pilot regulator ceases when the back-pressure sensed on valve face 77 counterbalances the force of spring 68, thereby causing piston 65 to move to the closed position. The seal is obtained between valve 78 and O-ring 78.

With piston 40 of the main regulator in the open position, high pressure air from 22 proceeds through openings 24 and then through the restricted opening near valve 48 at reduced pressure. When valve face 46 senses a reduced downstream pressure which counterbalances the pressure on piston rear face 41, piston 40 moves rearward and airow ceases when valve 48 contacts O-ring seal 38. However, when a demand is placed upon the main regulator (for example by operation of the flame thrower system), the pressure sensed on valve face 46 will lower thereby causing an unbalance of forces acting respectively on faces 46 and 41. The higher pressure on face 41 will cause piston 40 to move forward thereby unseating the valve face 48 from O-ring seal 38. When the downstream demand ceases, piston 4t) will again move rearward and airow will cease. This cycle is continually repeated. It is to be noted that valve faces 47 and 42 within the high pressure chamber are of equal area and opposed to each other and hence have no bearing on the balance of forces which operate the valve. Since O-rings 38 and 42' are of the same diameter, the only forces which operate the valve are those which result from the pressure on rear face 41, sealed by O-ring 42', and from the downstream back-pressure acting against valve face 46, sealed by O-ring 38 and valve 48. Accordingly, this pressure reducing valve, being balanced in the high pressure chamber, will maintain a constant reduced outlet pressure which is dependent only upon the setting of the pilot regulator. The net result is that the high pressure supplied through the inlet port is reduced to a selected and substantially lower working pressure when it passes through the outlet nozzle 14 which enables the llame thrower or other appliance to operate at maximum eiciency for a maximum period of time. When properly adjusted, the valve of the invention can reduce fluid pressure of approximately 3000 p.s.i.g. to a working pressure of approximately 400 p.s.i.g.

Turning now to the valve 78, as soon as the desired pressure is achieved in the skirt 43, the valve 78 is closed and remains closed until a different Working pressure is desired. The valve 78 moves rearward and closes when the pressure on the forward face counteracts the force exerted by the spring 68. Adjustments to the valve 78 to achieve specific outlet pressures are made by loosening the lock-nut 73 and turning the screw in one direction to increase the pressure and in the other to decrease pressure. When the desired outlet pressure is attained, the lock-nut 73 is tightened. For maximum sensitivity, vent holes 74 are required to maintain equalized pressure within the skirt 66. By properly adjusting the spring 68, the degree to which the valve 78 is held open, and therefore the pressure of the by-passed air can be regulated with the resultant variance in the amount of back pressure required to close the valve 48. Thus the operating or working pressure can be reduced accurately as required for the best performance.

It follows from the foregoing that the invention pro-- vides a fluid balanced reducing valve which is easily adjustable to regulate and reduce high pressures to a variety of selected lower pressures. This result is accomplished by a device which is strong and sturdy in use, which is simple to operate, maintain and repair, and which is highly efficient for the purpose specified.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred embodiment of same, and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

We claim:

1. In a balanced valve including a cylinder, means mounting a valve head for reciprocal movement in said cylinder; the improvement comprising a seat for said valve having a circumferential groove formed in said cylinder inwardly thereof, said groove having a floor and side Walls, said groove being formed with means venting the same, a back-up ring in said groove, said back-up ring being formed with integral projecting means slightly spacing the same from at least one Wall of said groove, said back-up ring being formed with axially extending peripheral notches slightly spacing the same from the iioor of said groove, said notches and projecting means comprising means for venting said back-up ring, said back-up ring having an inner periphery formed with a circumferential seat having an arcuate cross section, a resilient O-ring seated in said seat, and said O-ring having a portion projecting radially inwardly of said back-up ring and cylinder to provide said seat for said valve head.

2. The structure of claim 1, wherein said notches are disposed intermediate said projecting means.

3. In a balanced valve including a cylinder, means mounting a valve head for reciprocal movement in said cylinder; the improvement comprising a seat for said valve having a circumferential groove formed in said cylinder inwardly thereof, said groove having a floor and side walls, said groove being formed with means venting the same, a back-up ring in said groove, said back-up ring being formed with integral circumferentially spaced means slightly spacing the same from at least one wall of said groove providing means for venting said back-up ring in radial directions, said back-up ring being formed with integral circumferentially spaced means for venting the same axially along the floor of said groove, said back-up ring having an inner periphery formed With a circumferential seat having an arcuate cross section, a resilient O-ring seated in said seat, and said O-ring having a portion projecting radially inwardly of said back-up ring and cylinder to provide said seat for said valve head.

4. The structure of claim 3 wherein said last named venting means are each interposed between two of said rst named venting means.

References Cited UNITED STATES PATENTS 718,694 1/1903 Chapman 137-505.18 1,988,726 1/ 1935 Gordon 277-27 2,537,249 1/1951 Walton.

2,616,653 11/1952 Tarr. 2,722,402 ll/ 1955 Crookston 251-324 2,982,294 5/ 1961 Koutnik 137-1165 3,105,517 10/ 1963 Alfieri 251-332 XR 3,153,540 10/1964 Naperala 277--78 XR FOREIGN PATENTS 464,506 4/1950 Canada.

WILLIAM F. ODEA, Primary Examiner. H. W. WEAKLEY, Assistant Examiner.

Claims

1. IN A BALANCED VALVE INCLUDING A CYLINDER, MEANS MOUNTING A VALVE HEAD FOR RECIPROCAL MOVEMENT IN SAID CYLINDER; THE IMPROVEMENT COMPRISING A SEAT FOR SAID VALVE HAVING A CIRCUMFERENTIAL GROOVE FORMED IN SAID CYLINDER INWARDLY THEREOF, SAID GROOVE HAVING A FLOOR AND SIDE WALLS, SAID GROOVE BEING FORMED WITH MEANS VENTING THE SAME, BACK-UP RING IN SAID GROOVE, SAID BACK-UP RING BEING FORMED WITH INTEGRAL PROJECTING MEANS SLIGHTLY SPACING THE SAME FROM AT LEAST ONE WALL OF SAID GROOVE, SAID BACK-UP RING BEING FORMED WITH AXIALLY EXTENDING PERIPHEAL NOTCHES SLIGHTLY SPACING THE SAME FROM THE FLOOR OF SAID GROOVE, SAID NOTCHES AND PROJECTING MEANS COMPRISING MEANS FOR VENTING SAID BACK-UP RING, SAID BACK-UP RING HAVING AN ARCUATE CROSS SECTION, A A CIRCUMFERENTIAL SEAT HAVING AN ARCUATE CROSS SECTION, A RESILIENT O-RING SEATED IN SAID SEAT, AND SAID O-RING HAVING A PORTION PROJECTING RADIALLY INWARDLY OF SAID BACK-UP RING AND CYLINDER TO PROVIDE SAID SEAT FOR SAID VALVE HEAD.