PRESSURE REDUCING DEVICE

Abstract

A pressure reducing device having an upstream end connected to a pressurized gas source and a downstream end connected to a coupled installation. The device includes an operational fluid circuit having a pressure reducing unit configured to reduce the pressure of a pressurized gas flow to a maximum pressure P.sub.A, an emergency shut-off valve and an outlet interface with a pressure capability P.sub.N. The safety relief device is configured to have at least two states. A closed state where the safety relief device is inactive and the emergency shutoff valve is open, when the pressure in the fluid circuit downstream of the pressure reducing unit is lower than a predetermined pressure P.sub.L. And an open state where the safety relief device is active and the emergency shutoff valve is closed, when the pressure in the fluid circuit downstream of the pressure reducing unit is higher to the predetermined pressure P.sub.L.

Claims

1. A pressure reducing device comprising an upstream end configured to be connected to a pressurized gas source and a downstream end configured to be connected to a coupled installation and comprising: an operational fluid circuit comprising a pressure reducing unit configured to reduce the pressure of a pressurized gas flow to a maximum pressure P.sub.A, an emergency shut-off valve and an outlet interface with a pressure capability P.sub.N, a relief fluid circuit comprising a first end connected to the operational fluid circuit downstream of the pressure reducing unit and a safety relief device, the relief fluid circuit comprising a second end connected to the emergency shutoff valve, and that the safety relief device is configured to have at least two states, a closed state where the safety relief device is inactive and the emergency shutoff valve is open, when the pressure in the fluid circuit downstream of the pressure reducing unit is lower than a predetermined pressure P.sub.L, and an open state where the safety relief device is active and the emergency shutoff valve is closed, when the pressure in the fluid circuit downstream of the pressure reducing unit is higher to the predetermined pressure P.sub.L, the predetermined pressure P.sub.L being between P.sub.A+5% and P.sub.A+500% and/or between P.sub.N+5% and P.sub.N+500% wherein the operational fluid circuit comprises a residual pressure valve and/or a non-return valve.

2. The pressure reducing device according to claim 1, wherein the operational fluid circuit comprises a main shutoff valve.

3. The pressure reducing device according claim 1, wherein the emergency shutoff valve is placed downstream the pressure reducing unit.

4. The pressure reducing device according to claim 1, further comprising a residual pressure valve, wherein the residual pressure valve is the emergency shutoff valve.

5. The pressure reducing device (1) according to claim 4, wherein the non-return valve is comprised in the emergency shutoff valve.

6. The pressure reducing device according to claim 1, wherein the safety relief device comprises a bursting disc.

7. The pressure reducing device according to claim 1, wherein the safety relief device comprises a safety relief valve.

8. The pressure reducing device according to claim 1, wherein the safety relief device and the emergency shutoff valve are connected through a fluid connection, said fluid connection comprising a reset valve.

9. The pressure reducing device according to claim 1, wherein the pressure reducing valve is a one-way valve.

10. The pressure reducing device according claim 1, wherein the pressure reducing valve is a two-way valve.

11. The pressure reducing device according to claim 1, further comprising a bleeding valve.

12. The pressure reducing device according to claim 11, wherein the relief fluid circuit comprises the bleeding valve.

13. The pressure reducing device according to claim 11, wherein the relief fluid circuit comprises a flap leaning against the bleeding valve.

14. The pressure reducing device according to claim 1, wherein a central part of the residual pressure valve comprises a first piston being mobile in a middle chamber, and in that the residual pressure valve has three connections: an entry connection fluidly connecting the pressure reducing unit outlet to the residual pressure valve, a first connection fluidly connecting the residual pressure valve outlet to the safety relief device and a second connection fluidly connecting the safety relief device outlet to the middle chamber of the residual pressure valve, and that in the open position of the safety relief device, the outlet interface is moved in a closed state by the first piston.

15. The pressure reducing device according to claim 14 wherein the central part of the residual pressure valve comprises a second piston, and in that the middle chamber is delimited by the first piston and the second piston, and that in the open position of the safety relief device, the bleeding valve is moved in a closed position by the second piston.

16. A device for storing and supplying compressed gas comprising a fluid source and a pressure reducing device according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0042] The invention is further elucidated in the appending figures and figure description explaining preferred embodiments of the invention. Note that the figures are not drawn to scale. The figures are intended to describe the principles of the invention.

[0043] FIG. 1 is a functional representation of the state of the art.

[0044] FIG. 2 is a functional representation of the core of the invention.

[0045] FIG. 3 is a zoomed in functional representation of the relief fluid circuit of a first embodiment of the invention, comprising a bursting disc as the safety relief device.

[0046] FIG. 4 is a zoomed in functional representation of the relief fluid circuit of a second embodiment of the invention, comprising a safety relief valve as the safety relief device.

[0047] FIG. 5 is a functional representation of a third embodiment of the invention, comprising a residual pressure valve.

[0048] FIG. 6 is a functional representation of a fourth embodiment of the invention, comprising a residual pressure valve and a non-return valve.

[0049] FIG. 7 is a zoomed in functional representation of a fifth embodiment of the invention, comprising a non-return valve, and where the emergency shutoff valve is a residual pressure valve.

[0050] FIG. 8 is a zoomed in functional representation of a sixth embodiment of the invention, where the emergency shutoff valve is a residual pressure valve, and where the non-return valve is comprised in the residual pressure valve.

[0051] FIG. 9 is a zoomed in functional representation of a seventh embodiment of the invention, where the safety relief device is a safety relief valve, where the residual pressure valve acts as the emergency shutoff valve, the invention comprising a reset valve and a bleeding valve.

[0052] FIG. 10 represents a sketch of an eighth embodiment of the invention, in particular its residual pressure valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] Unless stated otherwise, a same element appearing on different figures presents a single reference.

[0054] Furthermore, the terms first, second, and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.

[0055] A fluid flows from a starting point of a fluid circuit to an end point of a circuit, passing through parts of the fluid circuits, e.g., valves. Positions may be referred to as downstream or upstream of a certain part. Upstream is used to describe a position on the circuit, in or before the said part with respect to the direction of the fluid flow whereas downstream is used to describe a position on the circuit in or after the said part with respect to the direction of the fluid flow.

[0056] FIG. 1 has already been described regarding the state of the art.

[0057] FIG. 2 represents the core of the invention. A fluid source 12 feeds the pressure reducing device (PRD) 1, this fluid source being for example a vessel. The PRD 1 comprises an operational fluid circuit 101 and a relief fluid circuit 102. The PRD inlet can be opened by a main shutoff valve (MSOV) 2, the MSOV 2 being part of the operational fluid circuit 101. A pressure reducing unit (PRU) 3 is also situated on the operational fluid circuit 101, and is used as a control valve that reduces higher upstream pressure to predetermined lower constant downstream pressure. The PRU 3 can for example be operated by a spring set to allow a certain pressure to flow through it, the spring being preferably a Belleville spring. The main shutoff valve 2 and the pressure regulating unit 3 can be provided by single valve.

[0058] A Safety relief device (SRD) 6 is also connected to the system to detect any overpressure in the PRD 1. Such an overpressure downstream of the PRU 3 can for example be caused by a malfunctioning PRU 3, a failure of the PRU 3 or a setting error. The SRD 6 will open itself when an overpressure is detected (when subjected to an overpressure) and therefore, the fluid would pass through the open SRD 6. The relief fluid circuit 102 prevents any release of fluid outside of the PRD 1 as it is connected to an emergency shutoff valve (ESOV) 4. The ESOV 4 is used and configured to close the system when the SRD 6 is opened, by receiving the overpressure from the relief fluid circuit 102.

[0059] An outlet interface 5 may be placed downstream of the PRD 1 and is used to let the fluid go out of the PRD 1 and to go to a coupled installation. A gas filter 13 may also be added to the PRD 1, preferentially upstream of the PRU 3. Such a gas filter may be used to filter out any unwanted particles in the system, such as dirt or rust particles.

[0060] All or some of the operational fluid circuit 101, relief fluid circuit 102, main shutoff valve (MSOV) 2, emergency shutoff valve (ESOV) 4 and outlet interface 5 may be integrated into a common body configured to be removably connected to a fluid source 2 (or separate bodies fluidly connected together). In particular, the pressure reducing device components might be integrated in valve block for gas cylinder and/or bundles. For example, a body or block might contain at least one or several among: pressure regulator 3, part of operational circuit 101, emergency shut-off valve 4, interface 5, pressure relief circuit 2, safety relief device 4, relief fluid circuit 102, burst disc.

[0061] An overpressure is defined as a pressure being higher than the limit allowable pressure P.sub.L of the coupled installation, P.sub.L being between P.sub.A+5% and P.sub.A+500% and/or between P.sub.N+5% and P.sub.N+500%, preferably +20%, P.sub.A and P.sub.N are generally comprised between 200 bar and 300 bar, depending on the coupled installation capabilities. That is to say, when the pressure downstream the pressure reducing unit 3 is abnormal (above the pressure capability P.sub.N of the outlet interface 5 and/or exceeds the maximum pressure P.sub.A of the pressure reducing unit 3 to a predetermined value such as +5% to 500% and preferably +20%) the safety relief device 6 is automatically opened, and the emergency shutoff valve 4 closed.

[0062] The SRD 6 can, for example, be a bursting disc 601 (BD), a safety relief valve 602 (SRV), balanced bellows, or power actuated, but the SRD 6 is preferentially a BD or a SRV.

[0063] A first embodiment is represented on FIG. 3, on which it shows a closer look at the SRD 6. In this first embodiment, the SRD 6 is a bursting disc (BD) 601. The BD 601 is a sacrificial part because it has a one-time-use membrane that fails at a predetermined pressure. If the BD 601 is burst, a simple replacement can be executed and maintenance on the PRD 1 becomes simple. In case of overpressure, the BD 601 bursts, letting the fluid flow in the relief fluid circuit 102 to the ESOV 4, said ESOV 4 closing the operational fluid circuit 101, and consequently the whole PRD 1, to avoid any overpressure going to the coupled installation.

[0064] A second embodiment is represented on FIG. 4, on which it shows a closer look at the SRD 6. In this second embodiment, the SRD 6 is a safety relief valve (SRV) 602. The SRV 602 is reversible, and the system could easily be reset. In case of overpressure, the SRV 602 opens, letting the overpressure fluid go through the relief fluid circuit 102 to the ESOV 4, said ESOV 4 closing the operational fluid circuit 101 to avoid any overpressure going to the coupled installation.

[0065] A third embodiment of the invention is represented on FIG. 5, on which a residual pressure valve (RPV) 7 is added. In this example, the RPV 7 is placed upstream of the ESOV 4, but the RPV 7 may as well be placed downstream of the ESOV 4. The RPV 7 allows to keep a small amount of pressure stored to help the ESOV 4 engage more quickly. A gas filter 13 is also placed on the system, the gas filter 13 filtering out any unwanted particles.

[0066] A fourth embodiment of the invention is represented on FIG. 6, on which a non-return valve (NRV) 8 is placed downstream of the ESOV 4. The NRV 8 allows the fluid to flow in only one direction and may be fitted to ensure that the fluid flows through the circuits in the right direction, where pressure conditions may otherwise cause reversed flow.

[0067] On FIG. 6, the RPV 7 and the NRV 8 are placed upstream and downstream of the ESOV 4 respectively. However, the position of the RPV 7 and the NRV 8 might vary, i.e. their places might be interchanged, both the RPV 7 and the NRV 8 might be placed upstream of the ESOV 4 or downstream of the ESOV 4.

[0068] The PRD 1 may have a NRV 8, and its position may vary. In addition, the number of non-return valves found in the PRD 1 may be more than one.

[0069] A fifth embodiment of the invention is represented on FIG. 7, on which a closer look is taken on the emergency shutoff valve. In this case, the RPV 7 is used as the emergency shutoff valve. The RPV 7 will therefore have two roles, and will be used to close the system when the SRD 6 is open. A NRV 8 may also be placed downstream of the RPV 7.

[0070] The RPV 7 can be used as an emergency shutoff valve, by connecting the SRD back to the RPV 7 through the relief fluid circuit 102. As stated earlier, the NRV 8 shown on FIG. 7 is optional, may be placed somewhere else on the PRD 1 and may not be the only NRV on the system.

[0071] A sixth embodiment of the invention is represented on FIG. 8, on which the RPV 7 acts as the ESOV 4, and where the RPV 7 comprises a NRV 8. This NRV feature might be added as a separate and complementary function.

[0072] A seventh embodiment of the invention is represented on FIG. 9, on which we can see a close look at the relief fluid circuit 102. In this seventh embodiment, the SRD is the SRV 602, and the ESOV 4 is the RPV 7.

[0073] A reset valve 9 is placed downstream of the SRV 602. The reset valve 9 is used to collect the overpressure at the back of the ESOV when the SRV 602, or more generally the SRD, is open. The reset valve is used to easily reopen the system by purging the zone downstream of the SRD and to the back of the ESOV (upstream).

[0074] The emergency shutoff valve 4 and/or the residual pressure valve 7 may use gaskets and/or seals such as O-ring seals, said gaskets and/or seals being prone to leak. These leaks would be minimal but might need consideration. Therefore, the PRD 1 may comprise a bleeding valve 10, as shown on FIG. 9. The bleeding valve 10 allows minor amounts of fluid to be released from the system in case of, for example, leakage from elastomeric rings, to avoid any pressure build-up on the ESOV 4 or the RPV 7 that could hinder the system's core function, especially when the SRD 6 is not open. In addition, the bleeding valve 10 may also comprise a flap 1001, that would be pushed against the bleeding valve 10 in order to close it when the SRD 6 is open. This flap 1001 would deny the fluid to be released from the bleeding valve in case of pressure surge arising from the SRD 6. The flap 1001 may for example be made of polyurethane.

[0075] FIG. 9 presents the SRV 602 as the SRD, but neither the reset valve nor the bleeding valve is limited to be used with a SRV only. The SRV 602 is there for the illustration purposes only and the invention is not limited to this type of SRD.

[0076] FIG. 10 presents an eighth embodiment, focusing the view on the RPV 7. The residual pressure valve 7 comprises a middle chamber 701 in its central part, a front chamber 704, a back chamber 705 being respectively closer to the outlet interface 5 and to the bleeding valve 10, and also comprises a first piston 702. An entry connection 1102 connects the PRU 3 and the RPV 7, a first connection 1103 connects the RPV 7 (downstream) and the SRD 6 (upstream), and a second connection 1104 connects the SRD 6 (downstream) and the middle chamber 701 (upstream). If the pressure in the front chamber 704 of the RPV 7 and in the first connection 1103 is smaller than the pressure P.sub.L, the fluid would not flow through the second connection 1104 as the SRD 6 is not open. In the contrary, if an overpressure is detected and the SRD 6 is open, the first piston 702 would prevent the fluid flow from going out of the outlet interface 5 as the released pressure would push the first piston 702 toward the outlet interface 5 until it is fully closed.

[0077] The RPV 7 may also comprise a second piston 703, and the middle chamber 701 would be delimited by the first piston 702 and the second piston 703 on each side, and that in the open position of the safety relief device 6, the bleeding valve 10 is closed by the hinged flap 1001 as it is being pushed by the second piston 703 and is extending itself on the bleeding valve 10.

[0078] When the safety relief device 6 is open, the first piston 702 is pushed by the first springs 7021 as well as the pressure released to the middle chamber, said first piston 702 being pushed towards the outlet interface 5 in order to close the operational fluid circuit 101. Similarly, when the SRD is open, the second piston 703 is pulled away by the overpressure fluid released by the SRD to allow the flap 1001 to close the bleeding valve 10. A second springs 7031 could be used to reopen the bleeding valve 10.

[0079] While the invention has been described in conjunction with specific embodiments thereof, it is important to note that combinations of embodiments is feasible and may be considered.