FR2616509A1 - PNEUMATIC CONTROL VALVE AND HYDROPNEUMATIC ACCUMULATOR EQUIPPED WITH THIS CLAMP - Google Patents

Abstract

Pneumatic valve 1 and accumulator 25 equipped with this valve 1. The valve 1 comprises a small reservoir 2 containing a membrane 7 and a piston 9. The membrane 7 contains gas. When the pressure of the fluid filling a pipe 6, arranged here at the outlet of a nitrogen overhead accumulator 25, drops, the membrane 7 expands and pushes a head 11 of the piston 9 so as to obstruct the pipe 6. The system is adjustable and reversible. General application to hydraulic or pneumatic circuits.

Description

1i 2 6 1 6 5 0 9

  PNEUMATIC CONTROL VALVE AND HYDROPNEUMATIC ACCUMULATOR

EQUIPPED WITH THIS CLAP

DESCRIPTION

  The present invention relates to a pneumatically controlled valve. It also relates to a battery

  hydropneumatic equipped with this valve.

  The purpose of some valves is to obstruct a pipe carrying fluid in the event of a drop in pressure. These valves are terminated by a rod and slide radially in the pipe; a spring surrounds the rod and pushes back the valve so as to effect the obstruction, which actually takes place when the pressure of the fluid can no longer

counteract the action of the spring.

  The drawbacks of such valves are essentially the impossibility of adjusting them and the uncertainty of the behavior of the springs over a long service life; in the case of large calibration pressures, there is added the size of the spring, so the valve. This is why we propose here a different device that avoids these disadvantageous features. The valve device according to the invention comprises in fact a small reservoir whose capacity is divided into two parts by an elastic membrane; one is filled with gas, the other fluid flowing in the pipeline. When the pressure decreases, the membrane is stretched under the effect of the expansion of the gas and eventually reaches a valve and the

  push back until you realize the obstruction.

  This valve is particularly advantageous for so-called nitro-sky hydropneumatic accumulators, the liquid content of which is pressurized by a gas supply pipe opening into the reservoir of the accumulator: the gas supply circuit can be used also for the valve reservoir without excessive complication; otherwise,

2 2616509

  we seek a dump as full as possible of the accumulator without however risk of blowing gas into the pipe, and must therefore know with great precision

  the liquid pressure corresponding to the closing of the valve.

  More specifically, the invention firstly relates to a pneumatically actuated valve installed on a fluid line, characterized in that it comprises a reservoir, an elastic membrane contained in the reservoir and delimiting a first and a second variable volumes, the first volume being filled with gas and the second volume communicating with the pipe, a connection communicating the second volume with the fluid pipe, and a piston sliding in the connection and likely to occupy a closed position o he is in contact with the membrane and discharged by it under the pressure of the gas filling the first volume and

  o It prevents the fluid from circulating by obstructing the pipe.

  In a preferred embodiment, the piston comprises a rod terminated by two opposite heads, the rod sliding in the connection, the diaphragm displacing the piston by contact with one of the heads and the second head bearing, in the closed position, on a seat established around a fluid flow orifice in the pipe so as to plug said orifice. The subject of the invention is also a hydropneumatic accumulator equipped with such a valve and further comprising a reservoir of larger dimensions than that of the valve, pierced with an orifice for introducing inert gas, the liquid flowing in the pipeline being contained in the bottom of the tank of

  the accumulator and pressurized by the inert gas.

  Other features of the invention will appear from the commentary of the appended figures and given for illustrative and nonlimiting purposes: - Figure 1 shows a valve according to the invention; - Figures 2 and 3 show the valve of Figure 1 equipping a hydropneumatic accumulator in two different operating states; - Figure 4 represents another possible arrangement

  of the valve relative to the accumulator.

  - Figure 5 shows another application of the valve, as a safety valve avoiding the appearance

  overpressure in a capacity.

  FIG. 1 firstly comments. The valve assembly 1 according to the invention firstly consists of a tank 2 pierced at one end of an orifice 3 allowing a pipe 4 for supplying gas from The reservoir 2 is provided, opposite the orifice 3, a connection 5 with a fluid line 6 having an upstream portion 6a and that the valve must be able to obstruct. The reservoir 2 is divided into two variable volumes Vg and Vf separated by an elastic deformable membrane 7. The orifice 3 opens into the volume Vg while the connection 5 is crossed by another orifice 8 which opens at

  both in line 6 and in the other volume Vf.

  The valve 1 also comprises a piston 9 consisting of a rod 10 and two heads 11 and 12 at both ends. The piston 9 slides in the orifice 8 of the connection 5 by means of a reinforcement 13 which is installed in the orifice 8 and which holds the rod 9 radially in place in rings 18 supported by spacers 19 connected to the connection 5. There is therefore a radial gap between the rod 9 and the connection 5, which allows the liquid contained in the

  channel 6 to enter the volume Vf.

  A first head 11 of the piston 9 performs a translational movement back and forth in the volume Vf, and the other head 12 performs a corresponding translation inside the pipe 6. The translation of the piston 9 is however limited by a seat 14, established around an orifice of the pipe 6 upstream of the valve 1 and referenced 15, on which the second head 12 is likely to be supported in a so-called closing position, during which the head 12 completely obstructs the orifice 15 of the pipe 6 and thus prevents the fluid

2616 5 0 9

  present in this pipe to circulate.

  A sealing support of the second head 12 may be provided by a projection 17 in a thin ring concentric with

  the orifice 15 and which makes contact with the seat 14.

  The piston 9 may be provided with a return spring 16, taking for example support on the armature 13 and pressing the first head 11 which exerts on the piston 9 a thrust tending to

  move it away from the closed position.

  The first head 11 comprises a convex convex surface 20 on the side of the membrane 7, and a cylindrical surface 21 notched with a groove for a seal 22. Its shape allows it to be able to sink into a recess 23 of the connection 5 which constitutes a transition between the orifice 8 and the volume Vf; this recess comprises a cylindrical surface 24 of diameter slightly greater than that of the cylindrical surface 21 of the first

  head 11, against which the seal 22 can rub.

  The operation of this valve will be described in connection with a preferred application that we will now

  describe using Figures 2 and 3.

  The valve 1 is here inside a nitrogen-filled hydropneumatic accumulator 25 consisting of a second reservoir 26, of dimensions much larger than those of the reservoir 2 of the valve 1, and which is pierced with three orifices: an upper orifice 27 for introducing inert gas into the tank 26, a lower orifice 28 through which the pipe 6 opens out of the tank 26, and a third orifice 29 allowing the gas supply pipe 4

  in the valve 1 to pass through the reservoir 26.

  For the sake of simplification, it is possible to choose the same gas for filling the two tanks, for example nitrogen, and the gas supply lines in the tank 2 of the valve 1 and the introduction of gas into the tank 26 of the accumulator 25 (the latter being referenced 30) can join in a single pipe 31 outside the accumulator 25. The three pipes 4, 30 and 31 are respectively provided with valves

  32, 33 and 34 allowing the gas to flow in both directions.

  The liquid pipe 6 is also provided with a valve 35 referenced from the reservoir 26 of the accumulator allowing the circulation of liquid in both directions or the obstruction of the pipe 6. In FIG. 2, the FIG. accumulator 25 approximately filled with liquid, to a level 39, and it was put under pressure by blowing nitrogen into the pipes 4 and 30 opening into the two tanks 2 and 26. The membrane 7 takes a shape o it is partially detached from the wall of the tank 2 and is not in contact with the convex curved surface 20 of the first head 11 of the piston 9. The spring 16 therefore pushes the piston 9 towards the inside of the tank 2, here upwards, and the liquid filling the reservoir 26 of the accumulator 25 also fills the volume Vf. The second head 12 of the piston 9 is detached from the seat 14, so that the

  duct 6 is obstructed only by the valve 35.

  Successive openings of this valve 35 lead to the progressive emptying of the reservoir 26 of the accumulator 25. The level 39 of liquid constantly decreases. As a result,

  gaseous volume increases in each of the two tanks 2 and 25.

  The membrane 7 is deformed progressively, but its expansion is stopped by the wall of the tank 2 of the valve 1, which it marries

the form.

  Finally arrives at the state shown in FIG. 3: the reservoir 26 of the accumulator 25 is almost emptied of its liquid, and the outlet pipe 6 is about to be dewatered. The passage of gas in line 6 would be disastrous in applications where pressurized liquid is required, such as the use of high capacity energy reserves, for example emergency injection,

  lifts, wave compensators.

  The pressure of the gas present in the reservoir 26 decreases, and reaches the precharge pressure of the membrane 7 of the valve 1, the expansion of which is limited, so that a large force

2616 5 0 9

  directed downwards is exerted via the membrane 7 on the first head 11 of the piston 9, sufficient. to close the piston 9 and overcome the pressure of the fluid at the inlet of the orifice 15 and the force of the return spring 16. The thin ring 17 of the second head 12 of the piston 9 comes into contact with the seat 14 and obstructs completely the orifice 15 of the pipe 6. The flow out of the accumulator 25 is

  stopped, and the nitrogen remains imprisoned there.

  The filling of this accumulator 25 is possible and

  can be done -the valve 35 of the pipe 6 being open-

  first opening the valves 32 and 34 of the pipes 4 and 31 so as to let the membrane 7 to deflate. The piston 9 is then pushed upwards by means of the spring 16 and the residual pressure in the reservoir 26 of the accumulator 25. The valve 33 of the pipe 30 is then opened so as to reduce the pressure in the reservoir 26 and thus be able to fill it more conveniently with liquid using a pump disposed at the outlet of the pipe 6. When the filling is carried out, it is possible to inflate the membrane 7, close the valve 32, then pressurizing the liquid in the reservoir 26 by injecting nitrogen through the pipe 30, and finally closing the

valves 33 and 34.

  The valve 1 according to the invention can also be arranged in different ways with respect to the accumulator 25. It is

  for example possible to arrange it outside of it.

  This is shown in Figure 4. It works however exactly as in the example given above and will not be described in detail here. It should be noted, however, that this construction makes it unnecessary to pierce the reservoir 26 of the accumulator 25 to pass the pipe 4 which remains here entirely external. The valve 1 can be firmly and simply held on the accumulator 25 if it is provided with a flange 40 screwed on a circular bearing 41 established around a port 42 of the liquid outlet through the wall of the reservoir 26. This arrangement allows to insert, according to an advantageous characteristic, a safety valve 43 between the flange 40 and the bearing surface 41. It is then possible to disassemble the valve I and possibly replace it without having to empty

completely the accumulator 25.

  The advantage of the seal 22 is to facilitate the filling of the accumulator 25 by the pipe 6. When the piston 9 is in contact with the seat 14, the seal 22 rubs against the cylindrical surface 24 of the recess 23 and therefore prevents the liquid to enter immediately into the volume Vf, which would result in a pressure on the curved surface 20 opposing the detachment of the piston 9. It can then be envisaged to remove the

return spring 16.

  Another way of ensuring the filling in a safe way is to make it by a bypass line 44, provided with a valve 45 and opening between the pipe opening 15

  and the reservoir 26 of the accumulator 25.

  Advantageously, the membrane 7 is an ovolde resting bladder which, as shown in Figure 2, is similar in shape to the tank 2 and only slightly smaller dimensions. The membrane 7 is fixed to the tank 2 near the connection 3 of the pipe 4. During its expansion, the membrane 7 undergoes only a slight radial and axial expansion so as to match the internal shape of the tank 2 and the first one. head 11, but this expansion is limited, so that the stresses on the membrane 7 remain small. A similar advantage would be offered by a reservoir 2 in the form of a short cylinder and occupied by a tense median circular membrane whose travel would thus be limited to a

low amplitude.

  The advantage of the valve according to the invention with respect to the valve of the prior art, which ensures the closure of the pipe in the event of depressurization using a calibrated spring, firstly to the perfectly known nature gas, the volume of which can be determined according to the

8 2 6 1 2616509

  pressure and temperature, while the behavior of a spring is difficult to know precisely, especially as it may vary over time especially in case of corrosion and creep. A second important advantage is that the trigger pressure of the valve 1 can be adjusted by

  vary the amount of gas that fills. the membrane 7.

  Other modifications of this valve may easily occur to those skilled in the art without departing from the scope of the invention. Similarly, it is clear that the use of such a valve is not limited to a hydropneumatic accumulator for which it however offers the additional advantage of being able to be powered by the same gas circuit as the reservoir 26 of the accumulator 25 and for which a very high precision is desired, so as not to have to conserve too much liquid at the bottom of the tank 26 to avoid the risk of blowing gas

in line 6.

  In a general manner, the valve 1 can be used to interrupt the flow of fluid in a hydraulic or pneumatic circuit as soon as the pressure of this fluid drops below a determined limit. This is the case of the application shown. in Figure 5 o the valve 1 jioue relief valve relief for a capacity, such as reservcir 46. In this. In this case, the tank 46 is joined to the outside via the intermediary of the pipe 6, with interpcation of the valve 1 according to the invention. Two valves 47 and 48, placed on each side of the valve 1, respectively between the reservoir 46 and the valve, and between the valve and the part of the pipe 6 connected to the outside, allow the valve to be removed, without loss of pressure in the reservoir 46, by means of two flanges 49 and 50 placed on a pipe 6, between the valve 1 and, respectively, the valves

47 and 48.

2616,509

Claims (9)

  1. Valve (1) with pneumatic control installed on a pipe (6) fluid, characterized in that it comprises a reservoir (2), an elastic membrane (7) contained in the reservoir (2) and delimiting a first and a second variable volume (Vg, Vf), the first volume (Vg) being filled with gas and the second volume (Vf) communicating with the channel (6), a connection (5) communicating the second volume (Vf) with the pipe (6) fluid, and a piston (9) sliding in the connection (5) and capable of occupying a closed position o it is in contact with the membrane (7) and discharged by it under pressure gas filling the first volume (Vg) and where it prevents the fluid from circulating by obstructing the channeling (6).   Pneumatically operated valve according to Claim 1, characterized in that the piston (9) comprises a rod (10) terminated by two opposing heads (11, 12), the rod (10) sliding in the connection (5), the membrane (7) displacing the piston (9) by contact with one of the heads (11) and the second head (12) pressing, in the closed position, on a seat (14) established around an orifice (15) ) of fluid circulation in the   pipe (6) so as to plug said orifice (15).   3. Pneumatically operated valve according to one   any of claims 1 or 2, characterized in that   comprises a return spring (16) exerting on the piston (9) a   force tending to move it away from its closed position.   4. Pneumatically operated valve according to one   any of claims 1 to 3, characterized in that   comprises an orifice (3) formed in the reservoir (2) communicating the first volume (Vg) with a feed pipe of gas (4).   5. Pneumatically operated valve according to one   any of claims 2 to 4, characterized in that   first head (11) has a cylindrical surface (21) 2616 5 0 9   notched with a groove provided with a seal (22) coming into contact with the connection (5) in the closed position, thereby isolating   The second volume (Vf) of the pipe (6) fluid.   6. Hydropneumatic accumulator (25) equipped with flapper   (1) according to any one of the preceding claims,   and wherein the pipe (6), the fluid of which is a liquid, opens out, characterized in that it comprises a reservoir (26), larger than that (2) of the valve, pierced with a hole (27). ) of introduction of inert gas, the liquid flowing in the pipe (6) being contained in the bottom of the reservoir (26) of the accumulator (25) and pressurized by the inert gas. 7. Hydropneumatic accumulator according to claim 6, characterized in that the valve (1) is located   out of the reservoir (26) of the accumulator (25).   8. Accumulator hydropneumatique according to claim 6, characterized in that the pipe is provided with a valve (43) between the reservoir (26) of the accumulator (25) and the valve (1).   9. Application of a valve according to at least one of the   1 to 5, as a safety valve suitable for   maintaining a capacity (46) at a set pressure, characterized in that said pipe (6) joins said outdoor ability.