FR2563312A1 - PRESSURE REDUCTION VALVE - Google Patents

Abstract

The invention relates to a device formed by a combination of a pressure reducing valve and a pressure relief valve. THE DEVICE INCLUDES A PISTON 61 WHICH CAN SLIDE ALTERNATIVELY IN A CYLINDER AND FEATURING A CENTRAL PRESSURE REDUCTION VALVE 67, OPENED BY ENTRY IN CONTACT OF A ROD 69 WITH A STOP 73 PROVIDED ON THE CYLINDER WHEN THE PRESSURE REIGNING ON THE SIDE DOWNSTREAM OF THE PRESSURE REDUCTION VALVE FALLS BELOW A PREDETERMINED FIRST VALUE, AS WELL AS A RELIEF VALVE 70, ALSO CARRIED BY PISTON 61 AND WHICH OPENS WHEN THE PRESSURE ON THE DOWNSTREAM SIDE OF THE PRESSURE REDUCING VALVE 67 INCREASES BEYOND A SECOND PRESET VALUE THAT IS HIGHER THAN THE FIRST PRESET PRESSURE.

Description

The present invention relates to a pressure reducing valve for

reduce the gas pressure to

  high pressure, for example from higher pressures

  below 13,750 kPa to a substantially lower pressure, for example between 690 kPa and 1375 kPa. Pressure reducing valves for gases to be used at relatively high pressures

  bass are well known. For example, such a

  pope uses a C aphragm on one side of which the output pressure acts and on the other side of which acts a

  spring interposed between the diaphragm and a stop

  glable manually, the diaphragm controlling the position

  of a disc in relation to an annular seat of the

  Pope. Such pressure reducing valves are satisfactory for use without great precision, but they are not suitable for reducing pressures.

in a very large proportion.

  Similarly, British Patent No. 949,004 discloses a pressure reducing valve which is primarily intended to supply the pressure of the supplied water to a domestic water heater and which, although it is stated that it can be plugged into pressurized steam supply lines and other fluid or gas lines, would seem

  designed only for relatively low pressures.

  The valve described in this patent GB-A-949 004 comprises a cylinder, a piston being able to slide alternately in the cylinder and dividing it into a first chamber 0 adjacent to a first end of the cylinder and a second chamber adjacent to the second end of the cylinder. cylinder, a spring pushing the piston towards the first

  end of the cylinder, an outlet of the first

  first cylinder chamber, a bore formed through the piston and containing a pressure reducing valve,

  means controlling the valve according to the position

  piston in the cylinder, the outlet side of the valve communicating with the first cylinder chamber, and means sealingly isolated from the second cylinder chamber and connecting an orifice

  inlet to the inlet side of the valve.

  In the field of high-pressure gas piping, there has been a need for a system comprising a pressure reducing valve and means for reducing an overpressure in the case where it is established downstream of the valve

pressure reduction.

  According to the present invention, a pressure reducing valve as described above in GB-A-949 004 is characterized by a second bore formed through the piston and in which a safety valve is mounted against overpressures, arranged to ensure a discharge from the first chamber to the second cylinder chamber when the pressure in the first cylinder chamber

  increases beyond a predetermined value.

  The valve structure according to the invention has considerable advantages over a structure utilizing a pressure reducing valve and a separate relief valve whose inlet is connected to the outlet passage from the reduction valve.

  pressure. The valve structure according to the invention

  much less space (the reduction valve

  In most cases, the pressure relief valve and the safety valve do not occupy more space than the pressure reduction valve alone. It does not require more installation costs than the pressure reducing valve alone, and it is less expensive than two

separate valves.

  In a preferred arrangement, the safety valve comprises a shutter member and a spring urging said shutter member in a closing direction of the relief valve, a pressure prevailing in the first cylinder chamber tending to displace the shutter of the valve. in opposition to the

  springs in one direction causing the

  opening of the safety valve. However, alternatively,

  the relief valve may comprise an obturator element

  which tends to be pushed by the pressure

  in the first cylinder chamber in a direction causing closure of the safety valve, and a mechanical means adapted to move the shutter of the safety valve in the opposite direction during a movement of the piston to the second

  end of the cylinder beyond a predetermined point.

  For example, the relief valve may comprise a poppet valve loaded with a spring and whose rod bears against an abutment provided on the cylinder during

said piston movement.

  According to a second aspect of the present invention, a support for a pressure vessel comprises a neck provided with a circumferential groove, the support comprising a wall having a notch for receiving the neck, a seat for receiving the neck part. located outside the groove and means for pulling the wall carrying the notch and the seat towards each other. Preferably, the means

  to pull the wall and the seat towards each other

  take co-operating threads, one of the threads being provided on the cylinder of the pressure reducing valve.

  The invention can be put into practice by different

  However, a pressure reducing valve and a pressure vessel holder will now be described, together with a modification, by way of example, with reference to the accompanying drawings, in which: FIG. clarify, is divided into two halves corresponding to Figures la and lb) is a longitudinal sectional view of the combined assembly formed by the valve and the support; Figure 2 is an elevational and end view of the valve and support made from the right side of Figure 1; Figure 3 is a front elevational view and a smaller scale of the assembly formed by the valve and the support; and Figure 4 is a fragmentary longitudinal sectional view on an enlarged scale showing a portion of

  of Figure 1 with a modified safety valve.

  As shown in Figure 1, gas enters the valve from a pressure vessel (not shown) mounted at the right end, it passes through the valve to the left, looking at the figure, and it comes out at a lower pressure at the left end, from which it is channeled to the point

  of use (not shown). In the description that

  will follow, the front end of the valve must be

  considered the left end.

  The assembly shown in the drawings comprises a body 1 consisting of a main portion 2 having generally a bowl shape and having an end wall 3 and a side wall 4 defining a cylinder 5. Inside this cylinder 5 is arranged a piston rod guide 9 which comprises a first cylindrical wall portion 11 (which is screwed into the main body portion 2), a second portion of

  cylindrical wall 12 which has a larger section

  dull and extends forwardly from an outer annular projection 10 of the first cylindrical wall portion 11, and a boss portion 13 which is received in a counterboring 14 formed in the wall

  extreme 3 and which positions an O-ring of

  A bore 20 extends from the counter

  Bore 14 through the end wall 3. The end wall 3 is provided with a boss 16 on the outer side of which is screwed a retaining element 17 in the form of a bowl. The body also comprises a second cup-shaped retaining element 18 which is screwed at 19 to an outer cylindrical surface of the end wall 3. At the front end, the cylinder 5 is closed by a buffer generally designated by 7 This comprises a cylindrical element 107 which is closed at its rear end by a plug 6. The cylindrical element

  107 is screwed into the front end of the cylindrical wall.

12 to 8.

  A pressure vessel holder 21 is slidably mounted on the outer side of the main body portion 2 and on the surface

  corresponding outer part of the cylindrical wall

  12 of the piston rod guide 9 (these parts having equal outside diameters). This support essentially consists of a sleeve portion 22 which is prevented from completely disengaging while being able to be moved alternately by means of

  needle screws 23 which engage in a circumferential groove

  in the outer surfaces of the cylindrical wall portion 12 and the body portion 3. The sleeve portion 22 is partially closed near the rear end by a transverse wall 25 in which an opening 26 is formed. and it is partially closed at its rear end by an end wall 27 which is indented by a rope 28 (see Figures 1 and 2), which also cuts the cylindrical side wall rearwards as far as the transverse Daroi 25. end wall 27 is provided with a U-shaped notch 29, as shown in FIG.

Figure 2.

  An alternative movement of the support 21 of reci-

  under pressure is generated by a sleeve of

  31, having at one end an inwardly directed flange 32 which is placed between a shoulder 33 of the pad 7 and a stop ring 34 housed in a groove of the pad 7 so that the sleeve 31 can be rotated but unable to move axially relative to the body. A seal is established between the buffer 7 and the operating sleeve 31 by means of a sealing ring 37 which is housed in a groove 36 formed in the outer surface of the cylindrical portion 107. The control sleeve 31 is functionally connected to the support 21 by a thread with coarse pitch and two starts. Consequently,

  a rotation of the sleeve 31 produces an alternating movement

native of the support 21.

  Inside the retainer 18 is

  mounted a seat 41 which is generally cylindrical in shape

  and which has about the middle of its

  The outer surface of the seat 41 is cylindrical and the latter is arranged to move alternately inside the opening 26 formed in the transverse wall 25 and inside an opening 42. formed in the end wall of the retaining element 18. When the support 21 of the pressure vessel is in its retracted position (of extreme-left) inside

  the operating sleeve 31 (as shown in Fig. 1), -

  the seat 41 is prevented from moving rearwardly by abutting a rear edge 50 of the element 41 against the

  end wall 27 of the support 21 of the pressure vessel.

  The seat 41 is further guided inside the retaining element 18 by an outwardly directed flange 43 which is guided on the inner surface of the cup-shaped element 18. The separating wall 40 of the seat 41 and the associated rearwardly extending cylindrical wall together define a shaped recess 44.

  Cup to receive an appropriate profile head

  required (not shown) of a pressure vessel.

  The pressure vessel head (not shown) is carried by a neck provided with a groove and which is received in the notch 29 of the end wall 27, this end wall 27 fitting into the groove. Headquarters

  41 is pushed back (to the right as

  Fig. 1) by means of a compression spring 47 which extends between the end wall 3 of the body 1 and the partition wall 40. The partition wall 40 of the seat 41 is provided with a bore 48. In the bore is disposed a valve member 51 which includes a

  head 52 and a rod 54 extending through the beam

  wise 48 and protruding towards the rear of it.

  Sealing of the space formed between the bore 48 and the rod 54 is provided by a ring 200 which is housed in a groove 201 formed in the separating wall 40, the ring being held in position by a locking screw 202. The head 52 has a complex shape and it consists of three parts 56, 57, 58 of diameters

  different but all having a radial section cir-

  lar. The first part 56 is housed in the bore defined by an end wall 59 of the retaining element, its rear axial face abutting against a protuberance 55 directed towards the front and formed on the separating wall 40 of the seat 41. The second portion 57 is housed in the bore defined by the side wall of the retaining member 17 and the third portion 58 is housed in the bore 20 defined by the boss 16 of the body portion 2. The sealing of the space between the front axial face of the second part

8 25633 12

  57 of the head 52 and the rear axial face of the protuberance

  16 is provided by a ring 53. A bore 80 extends centrally over the entire length of the element

valve 51.

  The front end of the head 52 of the

  valve 51 is provided with a cylindrical seat 501 extending

  axially and of a diameter smaller than the bore 20.

  A valve seat 503 of similar cylindrical profile is formed on the head 507 of a second valve member 504 which is guided to move axially within a ring 505 which is mounted in the bore 20. There exists between the element 504 and the ring 505 sufficient space to allow a passage of gas between them. The element 504 is pushed back by a spring 506 which is applied on one side against the ring 505 and on the other side against the head 507 of the element 504. In the narrow annular gap surrounding the two valve seats 501, 503, there is provided a cylindrical outer sleeve 509 and, in the inner gap, there is provided a cylindrical inner sleeve 570. The two valve heads 501, 503 apply against one

  and the other side of a valve seal ring 511.

  Inside the cylinder 5 is a piston 61 provided with a rod 62 and a probe 77 and there is provided a stepped bore 63 extending through the piston, rod and probe. The sealing of the piston 61 relative to the cylindrical portion 12 is provided by means of a sealing ring 71 held in a groove 72 formed in the outer surface of the piston. In a counter-bored hole in the bore 63 at the left end, there is provided a plug 64 which is provided with an axial bore 601. A valve seat 602 of cylindrical shape extends rearward to A valve member 66 is mounted within the bore 63 and has a portion provided with a valve head 67 having a shape similar to that of the valve head 602. The element valve 66 is pushed forward by

  relative to the piston 61 by means of a helicoidal spring 60.

  Inner and outer sleeves and a sealing ring

  Valve clearance is provided as already specified for the valve described above. However, in

  In this case, the valve element 66, in the

  shown in the drawing, is prevented from moving sufficiently far forward to form the valve by means of a rod 69 which is received in the bore 601 of the pad 64, in the inner sleeve and in a seat 67 of the valve member 66. The rod 69 abuts at one end against the valve member 66 and is in contact at its other end with an adjustable stop 73 screwed into a hole of the shutter member 6. A coil spring 75 pushes the piston 75

  forward within the cylindrical wall 12.

  A safety valve (designated as a whole

  70) is mounted in a second bore 701 of the piston.

  This valve is of the same general type as the two

  papes already described and it comprises a fixed element 702 with an associated seat 703 and a movable member 704 with an associated seat 705, mounted inside the bore

  and pushed to maintain the valve in the posi-

  closure by means of a helical spring 706.

  As shown in FIG. 3, there is provided at the left end of the cylindrical portion 707 of the pad 7 a threaded end-piece 81 by means of which the valve 3e can be connected to a flexible tube 82 having at its far end a probe 83 provided with a neck 84 and a head 85, in a manner similar to that provided at the end of the pressure vessel. The head can be protected by a cap 86 held captive As by a chain 87 and the interlocking of the valve can be protected by a cap 88 held captive by a chain 89. If the tube 82 is long enough, the head 85 can to be inserted into the cell formed by the notch 29, which protects both the head and the cell, and which makes the caps 86, 88 unnecessary. The apparatus described operates in the following manner. The front end (left end looking at Figure 1) of the buffer 7 is connected to a

  point of use by the head 85, while the

  The mounting cable provided at the right end is pre-

  d for receiving a pressure vessel by rotation of the operating sleeve 31 to move the sleeve 22 to the right. This movement of the sleeve 22 separates the seat 41 from the stop constituted by the end wall 27 and the seat 41 is moved to the right

  of a lower distance which is determined by the

  in contact with the flange 43 with the outer wall

  This leaves behind the end wall 27 a free space in which the head (not shown) of a pressure vessel is lowered by sliding its groove in the notch 29 of the end wall. 27. The sleeve 31 is then rotated in the opposite direction to pull the end wall 27 to the left and to the back

  to the position shown in Figure 1.

  During this movement, the following processes take place

  successively: the head of the pressure vessel

  and is supported by the recess 44 in the end wall of the seat (thereby causing the head of the pressure vessel to be aligned with the stem 54 of the valve member 51), the rod 54 enters the bore of the head, the rod 54 enters the pressure vessel,

  and its tip opens a shut-off valve (not shown).

  Thus, a passage from the pressure vessel is opened through the passage 80 formed in

the valve member 51.

  The gas pressure acting on the head 507 of the second valve member 504 causes the latter to move to the left, in opposition to the thrust spring 506.

  This opens a gas flow passage between the man-

  inner cylinder 510 and the valve seats 501, 503, in front of the valve sealing ring 511, between the seats 501, 503 and the outer sleeve 509 and then in the bore 20. The passage continues in front of the ring 505

  and in the bore 63 of the piston 61. As mentioned above,

  above, the valve is held in this open position by the rod 69 and the gas can flow by crossing the flanges and the sealing ring and then passing between the rod 69 and the buffer 64 to arrive in a space 76 located in before the piston. It then passes through a hole 90 formed in the shutter element 6 to

  reach the point of use. The pressure in the

  pace 76 existing between the piston 61 and the ob-

  6 increases and the piston 61 then moves to the right in opposition to the force of the spring 75 and

  the pressure acting in the bore 20 placed at the end

  right of the probe 77 until the valve seat 602 has moved far enough to the right (pulling the valve assembly with it) to seal between the valve seats 602, 67 and the sealing ring. During this movement, the valve member 66 remains stationary relative to the stop member 73. Valve closure occurs for the required outlet pressure and is determined by adjusting the position of the stop member 73 and the elasticity constant

spring 75.

  When the pressure in the space 76 existing between the piston 61 and the shutter element 6 falls below the required pressure, the valve is at

  open again until pressure is restored.

  If the pressure in space 76 increased excessively

  above the required value, for example because of a fault in the main valve, or at the point of use, the gas pressure acting on

  the element 704 of the safety valve would move it

  to the right in opposition to the spring 706 and gas could then escape by crossing this valve and passing through a space 301 located behind the piston, through a passage 302 formed in the guide 9 of the piston rod, by a similar passage 303 arranged

  in the end wall 3 to reach the space 308.

  From there, it could pass through holes 304, 305 formed respectively in the seat and in the second retaining element 18 to escape into the atmosphere via a standard discharge valve 306 mounted in a passage 307 of the support 21 of the pressure vessel. This valve acts as an environmental seal. The value of excess

  of pressure at which an exhaust of

  The spring load on the exhaust valve 306 is selected such that the valve opens for a pressure difference.

  lower than that of the safety valve.

  The overpressure safety valve

  1 could obviously be replaced by a safety valve with stroke overruns (FIG. 4), that is to say a valve triggered not directly by the excess pressure prevailing in the space 76 but means of an actuating element

  valve 551 which extends from the valve-

  mushroom 552 beyond the end of the bore and which is actuated by its coming into contact with

13 25633 12

  the shoulder 553 of the sleeve 12 when the piston 61 moves back a distance greater than a given value. The valve actuating member is arranged so that a force acting on it to the left (looking at Figure 4) moves the valve away from its seat 554 in opposition to the force of a spring 555 and allows gas flowing from the left to

the right through the valve.

  For disassembly of the pressure vessel, the sleeve 31 is rotated in its original direction to move the carrier 22 to the right. The head of the container is taken out of the rod 54 to allow closure of the stop valve of the pressure vessel and, as soon as the pressure in the passage 80 decreases, the valve member 504 is moved to the right, closing the valve provided at the end of the rod 54. The volume of gas which is discharged into the atmosphere when the pressure vessel is removed is small: it corresponds simply to the volume contained

  80. Consequently, the obligation to

  to provide complicated vent systems.

  When the support 21 has reached its right-hand position, the pressure vessel can be removed and replaced with a new one. The support 21 can be held in axial position by a pawl 95 biased by spring and engaging in one or other of

  two grooves 96 formed in the support 21.

Claims (12)

  1.-Pressure reducing valve device   comprising a cylinder, an alternately displaceable piston   in the cylinder and dividing it into a first chamber adjacent to a first end of the cylinder and a second chamber adjacent to the second end of the cylinder, a spring urging the piston toward the first end of the cylinder, an exit port of the cylinder; first cylinder chamber, a bore   through the piston and containing a check valve   a means for controlling the valve depending on the position of the piston in the cylinder, the outlet side of the valve communicating with the first cylinder chamber, and a means for sealing the second cylinder chamber and connecting a cylinder chamber; inlet of the device to the inlet side of the valve, characterized in that there is provided a second bore (701) passing through the piston (61) and in which is mounted a relief valve (70), arranged to provide a discharge from the first cylinder chamber (76) into the second cylinder chamber (301) when the pressure in the first cylinder chamber   (76) exceeds a predetermined value.   2. Valve device according to claim 1, characterized in that the connecting means comprises a hollow rod (62, 77) extending from the piston (61) and telescopically engaged in an inlet passage (20). Valve device according to Claim 2, characterized in that the rod extends through an opening (14) in the second end (3). of the cylinder.   4. Valve device according to one of the claims   2 or 3, characterized in that the entrance passage   contains a spring loaded inlet valve (501-511).   5. Valve device according to claim 4, characterized in that the cylinder (5), the piston (61), the bore (63) formed through the piston and containing the pressure reducing valve, the hollow rod ( 62, 77) and the inlet passage (20) are arranged mutually coaxially.   6. Valve device according to any one   Claims 1 to 5, characterized in that it is   provided an exhaust passage (302, 303, 308, 304, 305)   starting from the second cylinder chamber (301) and containing   an exhaust valve (306) spring-loaded and opening for a lower pressure difference   to that to which the valve of sireté must open.   7. Valve device according to any one   Claims 1 to 6, characterized in that it is   provided a support (21) for a pressure vessel having a neck provided with a circumferential groove and adapted to be connected to said inlet of the valve device, the support comprising a wall (27) provided with a notch (29) for receiving the neck, a seat (44) for receiving the neck portion placed outside the groove and means (31) for pulling   the wall carrying the notch and the seat towards each other.   8. Valve device according to claim 7, characterized in that the means (31) for pulling the wall (27) and the seat (44) towards each other comprises cooperating threads (35), one of the threads being placed on the cylinder.   9. Valve device according to any one of   Claims 1 to 8, characterized in that the   safety device (70) comprises a shutter member (704) and a spring (706) urging the shutter element in a closing direction of the poppet valve, a pressure in the first cylinder chamber (76) tending to displace the said shutter member in opposition to spring bias in one direction   opening of the safety valve.   10. Valve device according to any one of   Claims 1 to 9, characterized in that   conque or each of two arbitrary or   one of the three valves constituted by the depression reducing valve, the safety valve (70) and the   inlet valve comprises a cavity, an ob-   rator disposed so as to be able to move in the cavity and means placed in the cavity and defining   in cooperation with the shutter member an annular wall   an elongate coupling member (501, 503; 602, 67; 703, 705) and an elongated annular space, said annular space comprising a resilient sealing member (511); the shutter member being urged by a biasing means (506; 60; 706) so that the wall   ring extends into the annular space and has   to force the sealing element to form a tight seal; and the valve being arranged   that when the shutter element is moved in oppo-   by means of thrust, the joint formed with the element   Sealing is interrupted to define a fluid flow path over or across the shutter member toward the outer side of the cavity. 11. Valve device according to any one of   Claims 1 to 8, characterized in that the valve   safety device comprises a shutter member (552), a pressure in the first cylinder chamber (76) tending to move the shutter member in a closing direction of the safety valve, and a mechanical means (551) adapted for move the shutter member of the valve in the opposite direction as the piston moves toward the second end of the valve   cylinder beyond a predetermined point.   12. Support for a pressure vessel comprising   a neck in which is formed a circumferential groove   ferential, characterized in that there is provided a wall having a notch for receiving the neck, a seat (44) for receiving the neck portion located outside the groove and a means (31) for pulling the wall carrying the notch and the seat towards each other.