Fluid device combining check valve and dual flow restrictor

Abstract

The invention relates to a fluid device (1) comprising an inlet (2) and an outlet (3) connected by a body (4) forming a passage between the inlet (2) and the outlet (3) wherein the device (1) comprises a check valve (5-11) shaped to prevent a flow of fluid from the outlet (3) to the inlet (2) and a flow restrictor (13-19) shaped to restrict the flow of fluid from the outlet (3) to the inlet (2). The flow restrictor is shaped to allow fluid to flow from the inlet (2) to the outlet (3) at a first flow rate when the pressure difference ([delta] P) between the outlet (3) and the inlet (2) is below a threshold (S), and to allow fluid to flow from the inlet to the outlet at a second flow rate substantially lower than the first flow rate when the pressure difference ([delta] P) between the outlet (3) and the inlet (2) is above the threshold (S).

Description

Technical Field

[0001] The invention relates to a fluid device comprising an inlet and an outlet and combining the functions of a non-return valve in one direction and a flow restrictor in another direction. Background Art

[0002] The on-tank valve (OTV) assembly is designed to be mounted at the top of a fluid tank to enable it to be connected to a line. The tank valve assembly provides fill, drain and safety functions. Advantageously, the use / discharge line includes a check valve to prevent fluid from flowing back into the tank. Advantageously, the use / discharge line also includes a flow restrictor that allows flow from the tank at a nominal use flow rate when a nominal back pressure is present, and that substantially restricts flow when no significant back pressure is present, thereby indicating a critical line rupture condition.

[0003] The present invention provides an advantageous concept for a tank valve assembly for combining these three functions in a particularly small volume. Summary of the invention

[0004] To this end, an object of the present invention is to provide a fluid device, which includes an inlet and an outlet connected by a main body, the main body forming a channel between the inlet and the outlet, wherein the device includes a check valve and a flow restrictor, the check valve being shaped to prevent the fluid from flowing from the outlet to the inlet, and the flow restrictor being shaped to allow the fluid to flow from the inlet to the outlet at a first flow rate when the pressure difference between the outlet and the inlet is below a threshold value, and to allow the fluid to flow from the inlet to the outlet at a second flow rate significantly lower than the first flow rate when the pressure difference between the outlet and the inlet is above the threshold value.

[0005] Specific features or embodiments that may be used alone or in combination are:

[0006] the check valve comprises a check piston and a check seat, wherein the check piston is adapted to be pushed towards the check seat by a fluid flowing from the outlet to the inlet, wherein the check seat has a check hole coinciding with the inlet, and the check piston comprises a check end portion which is arranged opposite to the check hole and is shaped in a complementary manner to the check hole so that the check end portion closes the check hole when pushed against the check hole,

[0007] the flow restrictor comprises a restrictor piston and a restrictor seat, the restrictor piston being adapted to be pushed towards the restrictor seat by the fluid flowing from the inlet to the outlet, the restrictor seat having a restrictor hole coinciding with the outlet, and the restrictor piston comprising a restrictor end arranged opposite the restrictor hole and shaped in a complementary manner to the restrictor hole so that the restrictor end closes the restrictor hole when pushed against it,

[0008] - the restrictor end is pierced by a leak facing the restrictor hole, the leak preferably being calibrated,

[0009] - the check piston and the limiter piston are arranged telescopically,

[0010] the check valve further comprises check biasing means tending to urge the check piston in the direction of the check seat, and the flow limiter further comprises limiter biasing means tending to move the limiter piston away from the limiter seat,

[0011] - the device further comprises a balancing biasing means tending to move the non-return piston away from the limiter piston,

[0012] - the non-return piston further comprises at least one non-return through hole,

[0013] - the limiter piston further comprises at least one limiter through hole,

[0014] The check seat coinciding with the inlet is made of the same material as the body or has a bored plug preferably threadedly mounted on the body, and the limiter seat coinciding with the outlet is made of the same material as the body or has a bored plug preferably threadedly mounted on the body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be better understood by reading the following description, which is given by way of example only, and by referring to the accompanying drawings, in which:

[0016] [ Figure 1 ] shows a cross-sectional view of the device in the presence of a pressure drop in the opposite direction,

[0017] [ Figure 2 ] shows Figure 1 A cross-sectional view of the device shown in , with a nominal pressure drop in the nominal direction,

[0018] [ Figure 3 ] shows that in the presence of a significant pressure drop (potentially indicating a pipeline rupture) Figure 1 A cross-sectional view of the device shown in

[0019] [ Figure 4 ] shows a flow diagram of a valve assembly containing a device,

[0020] [ Figure 5 ]and[ Figure 6 ] shows the Figure 1 An exploded perspective view of the device shown in,

[0021] [ Figure 7 ] shows a device without a balanced biasing device according to one embodiment in a cross-sectional view. DETAILED DESCRIPTION

[0022] Figure 2 The device 1 according to the invention is shown in its rest configuration. This configuration is also substantially identical to the nominal configuration when there is a slight negative pressure variation between the inlet 2 on the right side and the outlet 3 on the left side of the device 1. In this case, the device 1 allows passage from the inlet 2 to the outlet 3 and acts as a flow restrictor.

[0023] Figure 4 The figure in FIG. 1 shows a fluid flow diagram of an on-tank valve (OTV) assembly 30. Such a valve assembly 30 is designed to be mounted on top of a fluid tank 31 (e.g., a hydrogen tank) to enable it to be connected to a pipeline 32. The tank valve assembly 30 provides filling, draining, and safety functions. The pipeline 32 is used to fill the tank 31, or to extract the fluid contained in the tank 31 when in use.

[0024] A valve assembly 30 connects the tank 31 to a pipeline 32 via a main conduit. The main conduit houses the device 1. The main conduit also includes filters 35, 36 at each end. The main conduit also includes a solenoid valve 33 and a shut-off valve 34 connected in series with the device 1.

[0025] This main pipe is used for discharge. When valves 33, 34 are open, the fluid contained in tank 31 can flow to pipeline 32 from right to left.

[0026] The valve assembly 30 also comprises a first secondary conduit which houses a check valve 37 and branches from the main conduit. The first secondary conduit is designed to fill the tank 31. When the valve 34 is open and the solenoid 33 is closed, fluid can flow from the line 32 from left to right to the tank 31. The check valve 37 ensures that the fluid does not pass through the first secondary conduit during discharge.

[0027] The valve assembly 30 also comprises a second secondary conduit which houses a manual valve 38 and branches off from the main conduit. This second secondary conduit creates a bypass.

[0028] The valve assembly 30 also comprises a vent line including a safety valve 39 or TPRD (Thermal Pressure Relief Device) allowing the fluid to be discharged in case of overpressure.

[0029] The valve assembly 30 also includes a temperature sensor 40 that measures the temperature of the tank 31 .

[0030] In its position on the valve assembly 30 , the fluidic device 1 according to the invention advantageously performs three functions corresponding to three operating modes: a nominal use / discharge mode, a critical mode or a mode of use in case of an interruption in the line 32 , and a filling mode.

[0031] During the filling of the tank 31, the fluid pressure at the outlet 3 of the device 1 is higher than the fluid pressure at the inlet 2. The solenoid valve 33 is closed. The valve 34 is open. The valve 38 is closed. In the plane of the figure, the fluid flows from left to right. This flow passes through the first secondary conduit, in which the non-return valve 37 is passable. In this filling mode, the device 1 must act as a non-return valve to prevent excessive pressure stress on the solenoid valve 33.

[0032] During nominal operation, the fluid from the tank is used by the consumer connected to line 32. Solenoid valve 33 is open. Valve 34 is open. Valve 38 is closed. The fluid flows from right to left. This flow passes through the main line and through the device 1 from right to left, i.e. from inlet 2 to outlet 3. In this nominal discharge mode, the device 1 must be used as a flow restrictor with a calibrated orifice.

[0033] A disruption may occur in line 32. When a disruption occurs, the line switches to critical mode. In this critical mode, it is desired to significantly restrict the flow of fluid from tank 31. Solenoid valve 33 is still open. Valve 34 is still open. Valve 38 is still closed. Fluid still flows from right to left. The flow still passes through the main line and through the device 1 from right to left, i.e. from inlet 2 to outlet 3. In this critical mode, the device 1 must perform a significant flow restriction function, because the extracted fluid is considered lost.

[0034] To this end, the fluidic device 1 is a dipole, since it comprises an inlet 2 and an outlet 3 connected by a body 4. The body 4 forms a channel between the inlet 2 and the outlet 3.

[0035] The device 1 comprises a non-return valve 5-11. The non-return valve 5-11 is shaped to prevent the passage of fluid from the outlet 3 to the inlet 2, ie in the direction opposite to the nominal direction of use / extraction.

[0036] The device 1 further comprises a flow restrictor 13 - 19. The flow restrictor 13 - 19 is shaped to allow the fluid to flow in the direction of use, ie from the inlet 2 to the outlet 3. There are two modes: a nominal mode and a critical mode.

[0037] In nominal mode, the fluid circulates at a first or nominal flow rate. The nominal mode is characterized by the detection that the pressure difference ΔP between the outlet 3 and the inlet 2 remains low, ie below a threshold S. During nominal extraction, the fluid consumer ensures sufficient back pressure so that the pressure drop ΔP does not exceed the threshold S.

[0038] In critical mode, fluid circulation occurs at a second or critical flow rate that is significantly lower than the first flow rate. Critical mode is characterized by the detection of a large pressure difference ΔP between outlet 3 and inlet 2, i.e. greater than a threshold value S. An interruption in line 32 will result in a very low pressure at outlet 3, approximately equal to atmospheric pressure. The presence of a significant pressure at inlet 2 due to the presence of tank 31 will result in a significant pressure drop ΔP. Likewise, conversely, the detection of a significant pressure drop ΔP greater than threshold value S is interpreted as an interruption in line 32. Threshold value S distinguishes between nominal mode and critical mode.

[0039] In order to realize these functions, the present invention proposes a device 1 . Figures 1 to 3 , Figure 5 , Figure 6 An example of such a device 1 is shown in FIG. Figure 1 The device 1 is shown in a filling mode. Figure 2 The device 1 is shown in nominal mode. Figure 3 The device 1 is shown in critical mode.

[0040] To perform these three functions, the device 1 includes two components: a check valve 5-11 and a flow restrictor 13-19. These two components include many similar parts. To distinguish them, the check valve part 5-11 has the word "check" before its name, and the restrictor part 13-19 has the word "restrictor" before its name.

[0041] In order to perform the check valve function, the check valve 5-11 includes a check piston 5 and a check seat 6. The check piston 5 is slidable in the body 4. Specifically, the check piston 5 is shaped to be pushed in the direction of the check seat 6 by the fluid flowing from the outlet 3 located on the left to the inlet 2 located on the right, that is, from left to right in the plane of the figure. The check seat 6 has a check hole 9, which merges with the inlet 2 fluid and constitutes a unique fluid passage. The check piston 5 is shaped to be complementary to the check hole 9 at one of its ends (referred to as the check end 8). The check end 8 faces the check hole 9. Therefore, when the check piston 5 and its check end 8 are pushed against the check seat 6, the check end 8 closes the check hole 9, thereby preventing any fluid from passing.

[0042] The complementary shapes of the non-return end 8 and the non-return seat 6 on the edge of the non-return hole 9 are designed to provide a seal. These shapes are, for example, conical / conical or spherical / conical.

[0043] The non-return function desired in the application envisaged for the device 1 does not require a tight seal. A simple contact between the non-return end 8 and the non-return hole 9 is also sufficient. If a tighter seal is required, a seal can be added to the contact ring between the non-return end 8 and the non-return hole 9.

[0044] In order to perform two flow control functions, the flow restrictor 13-19 includes a restrictor piston 13 and a restrictor seat 14. The restrictor piston 13 can slide in the body 4. Specifically, the restrictor piston 13 is formed to be pushed in the direction of the restrictor seat 14 by the fluid flowing from the inlet 2 located on the right side to the outlet 3 located on the left side, that is, pushed from right to left in the plane of the figure. The restrictor seat 14 has a restrictor hole 17, which coincides with the outlet 3 fluid and constitutes a unique fluid passage. The restrictor piston 13 is formed to be complementary to the restrictor hole 17 at one of its ends (referred to as the restrictor end 16). The restrictor end 16 faces the restrictor hole 17. Therefore, when the restrictor piston 13 and its restrictor end 16 are pushed against the restrictor seat 14, the restrictor end 16 closes the restrictor hole 17, thereby substantially preventing all fluid from passing.

[0045] According to another feature, the restrictor end 16 is pierced by a leak 22. This leak 22 or leak channel is opposite the restrictor orifice 17 and therefore connects the outlet 3 to the right part of the restrictor piston 13 and therefore to the interior of the device 1. This leak 22 determines the leakage flow rate, i.e. the reduced flow rate, which is the only authorized flow rate in critical mode. This Figure 3 3. In critical mode, the very low pressure at the outlet 3 (relative to the pressure from the tank 31) causes a sharp drop in pressure in the device 1. This causes the fluid to push the restrictor piston 13 from the right to the left from the inlet 2 to the outlet 3. This then closes the restrictor seat 14. The only remaining outlet for the fluid is the leak 22, which passes through the restrictor piston 13, through the restrictor end 16 of the restrictor piston, and is aligned with the restrictor hole 17. The leak 22 is preferably calibrated.

[0046] According to another feature, the non-return piston 5 and the limiter piston 13 are arranged telescopically. This feature is very advantageous because it makes it possible to design a particularly compact device 1, mainly in terms of the length along its axis, and thus facilitates the integration of the device 1 into the valve assembly 30. For this purpose, each of the two pistons (non-return piston 5 and limiter piston 13) is bell-shaped on the side of their other end 10, 18, which is opposite to the end 8, 16 facing the seat 6, 14 respectively. The telescopic mounting is then made possible by the bell-shaped piece of one piston 5, 13 surrounding the bell-shaped piece of the other piston 5, 13. Therefore, as shown in the figure, the non-return piston 5 surrounds the limiter piston 13 essentially concentrically. The opposite, that is, the limiter piston 13 surrounds the non-return piston 5, is also possible and equivalent.

[0047] In order to produce a sensor capable of detecting different pressure drop values ​​determining the operating modes (nominal mode, critical mode and filling mode), it is advisable to arrange the biasing means 7, 15, 21 judiciously, their respective arrangement and rigidity will enable Figures 1 to 3 The three configurations shown in correspond to the modes of operation. A person skilled in the art knows how to determine the size of these biasing means according to the mode and the threshold S of the voltage drop value. The threshold S determines the mode change between the nominal mode and the critical mode. Another implicit threshold corresponds to the change in the voltage drop direction and determines the mode change between the nominal mode and the filling mode.

[0048] According to another feature, the check valve 5-11 also includes a check biasing device 7. The check biasing device 7 is arranged so that it tends to push the check piston 5 towards the check seat 6. This means that the check valve 5-11 is closed by default. The operating pressure from the inlet 2 to the outlet 3 pushes the check piston 5 and acts on the check biasing device 7 to open the check valve 5-11. The check biasing device 7 acts between the check piston 5 and the body 4. In a preferred embodiment, the check biasing device 7 is a compression coil spring, which is arranged between the other check end 10 of the check piston 5 and the body 4 to the left side of the check piston 5, that is, on the outlet 3 side. In the embodiment shown in the figure, the support is on the plug 23, which is considered here to be similar to the body 4.

[0049] According to another feature, the flow limiter 13-19 also includes a limiter biasing device 15. The limiter biasing device 15 is arranged so that it tends to move the limiter piston 13 away from the limiter seat 14. In this way, the flow limiter 13-19 is opened by default, thereby allowing a large initial flow rate to pass. A small pressure drop below the threshold S is not sufficient to press the limiter piston 13 against the limiter seat 14. The limiter biasing device 15 acts between the limiter piston 13 and the body 4. In a preferred embodiment, the limiter biasing device 15 is a compression coil spring, which is arranged between the other limiter end 18 of the limiter piston 13 and the body 4 to the left side of the limiter piston 13, that is, on the side of the outlet 3. In the embodiment shown in the figure, the support is on the plug 23, which is considered here to be similar to the body 4.

[0050] The device 1 according to the invention can be operated without the above-mentioned balancing device 21. Figure 7 Shown in.

[0051] However, such an apparatus 1 is more constrained in design. Such a design choice results in tighter tolerance constraints on the size of the check biasing means 7 and the limiter biasing means 15 and on the length of the respective telescopic parts of the check piston 5 and the limiter piston 13.

[0052] Therefore, according to another feature, the device 1 advantageously comprises a balanced biasing device 21. The balanced biasing device 21 is arranged so that it tends to move the non-return piston 5 away from the limiter seat 13. The balanced biasing device 21 acts between the non-return piston 5 and the limiter piston 13. In a preferred embodiment, the balanced biasing device 21 is a compression helical spring arranged between the non-return piston 5 and the limiter piston 13.

[0053] According to another feature, the non-return piston 5 further comprises at least one non-return through-hole 11. The at least one non-return hole 11 is a through-hole which enables fluid communication on both sides of the non-return piston 5. Furthermore, the total cross-section of the at least one non-return hole 11 is such as to allow a through-flow through the non-return piston 5 corresponding to the needs of the device 1 and in particular to allow a restricted flow in nominal mode. However, if the non-return piston 5 is to perform its piston function and to move under the action of a fluid flow coming from the left side of the non-return piston 5, the cross-section must be kept small. The at least one non-return hole 11 may be axial, as long as it is located on the periphery of the non-return piston 5. Alternatively or in addition, if the hole 11 is more centrally located, as in Figures 1 to 3 As shown in , the hole ends partially axially and radially on the side of the other non-return end 10 so as not to change the non-return piston 5 at the non-return end 8. The non-return end 8 must remain sealed, at least where it faces the non-return hole 9 in the non-return seat 6.

[0054] According to another similar feature, the limiter piston 13 also includes at least one limiter through hole 19. The at least one hole 19 is a through hole because it connects the fluid on both sides of the limiter piston 13. In addition, the total cross-section of the at least one limiter hole 19 is such as to allow a flow through the limiter piston 13 corresponding to the needs of the device 1, and specifically allows a limited flow in the nominal mode and a reverse flow in the critical mode until the check valve 5-11 is closed. However, if the limiter piston 13 is to perform its piston function and move under the action of a fluid flow from the right side of the limiter piston 13, the cross-section must be kept small. The at least one hole 19 can be axial, as long as it is located on the periphery of the limiter piston 13. Alternatively or in addition, if the limiter hole 19 is more central, then as Figures 1 to 3 , the restrictor hole ends partially axially and radially on the side of the other restrictor end 18 so as not to change the restrictor piston 13 at the restrictor end 16. The restrictor end 16 must remain substantially sealed, at least where it faces the restrictor hole 17 in the restrictor seat 14. The term "substantially" in the preceding sentence refers to the exception of the seal formed by the leak 22.

[0055] In nominal mode, such as Figure 2As shown, the restrictor piston 13 is not in contact with the restrictor seat 14. The nominal flow rate in the nominal mode is then the flow rate determined by the at least one check hole 11 and the at least one restrictor hole 19. More precisely, the nominal flow rate is the flow rate determined by the smaller cross section of the two holes 11, 19.

[0056] In critical mode, Figure 3 As shown in FIG. 1 , the restrictor piston is in contact with the restrictor seat 14 , so the restrictor 13 - 19 is locked. The critical flow rate is the flow rate determined by the leakage portion 22 .

[0057] The check piston 5 is biased to its closed position primarily by the check biasing means 7. The check piston 5 reaches a fully open stable position from a pressure threshold S, which is a function of pressure and flow. This position is reached when the ring of the non-biasing means 7 engages, or when the check piston 5 abuts against its seat.

[0058] For nominal conditions: drain mode and fill mode, the fluid passage holes are dimensioned such that the fluidic device 1 has a defined pressure loss coefficient.

[0059] In critical mode, the pressure difference is much higher than the threshold value S. When the non-return piston 5 reaches its stable position, the force of the balancing biasing device 21 on the limiter piston 13 no longer depends on the position of the non-return piston 5. Starting from the second pressure threshold value S2, the limiter piston 13 moves in the direction of the seat due to the increase in flow. The second threshold value S2 is much greater than the first threshold value S.

[0060] The leak 22 is calibrated according to several system operating parameters.

[0061] The balancing biasing device 21 must exert a permanent force to press the limiter piston 13 against the limiter biasing device 15. The stiffness of the balancing biasing device 21 is very low compared to the stiffness of the non-return biasing device 7 so as not to cause the limiter piston 13 to move when the non-return piston 5 moves.

[0062] According to another feature, the non-return seat 6 is made in one piece with the body 4. Alternatively, the non-return seat 6 is made of the same material as the plug 23. The body 4 or the plug 23 is then drilled to produce the non-return hole 9. The plug 23 is assembled with the body 4. This can preferably be achieved by screwing.

[0063] According to another feature, the limiter seat 14 is made in one piece with the body 4. Alternatively, as Figures 1 to 3 As shown, the restrictor seat 14 is made of a material with a plug 23. The body 4 or the plug 23 is then drilled to create the restrictor hole 17. The plug 23 is assembled with the body 4. This can preferably be achieved by screwing.

[0064] The plug 23 also provides access to the hollow interior of the body 4 into which all of the components 5-22 of the device 1 may be inserted during assembly.

[0065] The device 1 is shown with a plug 23 on the left outlet side. It is also possible to produce a device 1 with a plug on the right inlet side. The device 1 may also comprise two plugs, one on each side.

[0066] In decomposition Figure 5 and decomposition Figure 6 The stacking of components for assembling the device 1 is shown in more detail in FIG.

[0067] The invention has been described and illustrated in detail in the drawings and the foregoing description. This must be considered as illustrative and given by way of example, rather than limiting the invention to this description alone. Many alternative embodiments may be employed.

[0068] Reference numerals list

[0069] 1: Equipment,

[0070] 2: Input,

[0071] 3: Output,

[0072] 4: Main body,

[0073] 5: Check piston,

[0074] 6: Check seat,

[0075] 7: Non-return bias device,

[0076] 8: Check end,

[0077] 9: Check hole,

[0078] 10: Another non-return end,

[0079] 11: Check hole,

[0080] 13: Limiter piston,

[0081] 14: Limiter seat,

[0082] 15: Limiter bias device,

[0083] 16: Limiter end,

[0084] 17: Restrictor hole,

[0085] 18: Another limiter end,

[0086] 19: Limiter drilling,

[0087] 21: Balanced bias device,

[0088] 22: Leakage Department,

[0089] 23: Stopper,

[0090] 30: Valve assembly,

[0091] 31: cans,

[0092] 32: pipeline,

[0093] 33: Solenoid valve,

[0094] 34: valve,

[0095] 35, 36: Filter,

[0096] 37: Check valve,

[0097] 38: Bypass valve,

[0098] 39: Safety valve,

[0099] 40: Temperature sensor,

[0100] S, S2: threshold.

Claims

1. A fluid device (1), comprising an inlet (2) and an outlet (3) connected by a body (4), wherein the body forms a channel between the inlet (2) and the outlet (3), characterized in that: The device (1) comprises a check valve (5-11) and a flow restrictor (13-19), wherein the check valve is configured to prevent fluid from flowing from the outlet (3) to the inlet (2), and the flow restrictor is configured to allow the fluid to flow from the inlet (2) to the outlet (3) at a first flow rate when the pressure difference (ΔP) between the outlet (3) and the inlet (2) is lower than a threshold value (S), and to allow the fluid to flow from the inlet to the outlet at a second flow rate significantly lower than the first flow rate when the pressure difference (ΔP) between the outlet (3) and the inlet (2) is higher than the threshold value (S).

2. An apparatus (1) according to claim 1, wherein the check valve (5-11) comprises a check piston (5) and a check seat (6), wherein the check piston (5) is suitable for being pushed toward the check seat (6) by the fluid flowing from the outlet (3) to the inlet (2), wherein the check seat (6) has a check hole (9) coinciding with the inlet (2), and the check piston (5) comprises a check end (8), which is arranged opposite to the check hole (9) and is formed in a complementary manner to the check hole (9) so that the check end (8) closes the check hole when being pushed against the check hole (9).

3. An apparatus (1) according to any one of claims 1 or 2, wherein the flow restrictor (13-19) comprises a restrictor piston (13) and a restrictor seat (14), the restrictor piston (13) being suitable for being pushed toward the restrictor seat (14) by the fluid flowing from the inlet (2) to the outlet (3), the restrictor seat (14) having a restrictor hole (17) coinciding with the outlet (3), and the restrictor piston (13) comprising a restrictor end (16), the restrictor end being arranged opposite to the restrictor hole (17) and being formed in a complementary manner to the restrictor hole (17) so that the restrictor end (16) closes the restrictor hole (17) when being pushed against the restrictor hole (17).

4. Device (1) according to any one of claims 1 to 3, wherein the restrictor end (16) is pierced by a leak (22), said leak being opposite to the restrictor hole (17), preferably said leak being calibrated.

5. The device (1) according to any one of claims 1 to 4, wherein the non-return piston (5) and the limiter piston (13) are arranged telescopically.

6. Apparatus (1) according to any one of claims 1 to 5, wherein the non-return valve (5-11) further comprises a non-return biasing device (7), wherein the non-return biasing device (7) tends to push the non-return piston (5) towards the non-return seat (6), and wherein the flow restrictor (13-19) further comprises a restrictor biasing device (15), wherein the restrictor biasing device (15) tends to move the restrictor piston (13) away from the restrictor seat (14).

7. Apparatus (1) according to any one of claims 1 to 6, further comprising a balancing biasing device (21) tending to move the non-return piston (5) away from the limiter piston (13).

8. The device (1) according to any one of claims 1 to 7, wherein the non-return piston (5) further comprises at least one non-return through hole (11).

9. The device (1) according to any one of claims 1 to 8, wherein the restrictor piston (13) further comprises at least one restrictor through hole (19).

10. Device (1) according to any one of claims 1 to 9, wherein the non-return seat (6) coinciding with the inlet (2) is made of the same material as the body (4) or has a drilled plug (23) preferably mounted on the body (4) by threading, and the limiter seat (14) coinciding with the outlet (3) is made of the same material as the body (4) or has a drilled plug (23) preferably mounted on the body (4) by threading.

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