TANK SYSTEM AND VALVE ARRANGEMENT

Abstract

Tank system comprising a tank (2) and a valve arrangement with a pilot-controlled pressure relief valve (4), wherein the pressure relief valve (4) - a main valve chamber (10), - a filling line (22), - a pilot (16) and - has a control line (18), wherein the main valve chamber (10) is connected to the filling line (22) and can be filled with a filling medium via the latter, and wherein the control line (18) is connected to the tank (2) and the pilot (16) in such a way that the pilot (16) is opened when a pressure in the control line (18) exceeds a predetermined response pressure, whereby the pressure relief valve (4) is opened, wherein the valve arrangement has a reservoir (20) filled with a flushing medium, wherein the valve arrangement is designed to conduct the flushing medium at a flushing pressure into the control line (18) and / or into the filling line (22), characterized in that the tank system has a control system which is designed to control the flushing pressure in the filling line (22) and / or in the control line (18) in such a way that the flushing pressure is greater than the pressure inside the tank (2) by a predetermined value.

Description

[0001] The invention relates to a tank system comprising a tank and a valve arrangement with a pilot-controlled pressure relief valve, wherein the pressure relief valve has a main valve chamber, a filling line, a pilot, and a control line, wherein the main valve chamber is connected to the filling line and can be filled with a filling medium via the latter, and wherein the control line is connected to the tank and the pilot in such a way that the pilot is opened when the pressure in the control line exceeds a predetermined response pressure, whereby the pressure relief valve is opened, wherein the valve arrangement has a reservoir filled with a flushing medium, wherein the valve arrangement is configured to conduct the flushing medium at a flushing pressure into the control line and / or into the filling line. The invention also relates to a valve arrangement for such a tank system.

[0002] DE 27 31 804 A1 discloses a tank system with a valve arrangement controlled by a pilot valve. By adding gas to a reservoir, additional gas pressure can be generated, which presses the valve disk against the valve seat. This allows the actual set pressure to be adjusted. DE 34 14 294 A1 also shows a pilot-controlled safety valve for gas tanks. This valve also has an adjustment device with which the set pressure can be adjusted. Such tank systems are used, for example, to store large quantities of oil or gas, and they are also used to store chemicals in liquid or gaseous form. Filling and emptying, as well as temperature differences, can cause the medium stored in the tank of the tank system to expand, causing the pressure inside the tank to rise.It is important to prevent the pressure from becoming so high that the tank is damaged and the medium contained escapes uncontrollably into the environment.

[0003] To reduce the pressure inside the tank in a controlled manner in this situation, a valve arrangement with a pressure relief valve is used. The actual pressure relief valve has an inlet connected to the tank and an outlet, which can be connected to a pipe through which the medium escaping from the tank through the pressure relief valve can be discharged. When the pressure relief valve is closed, a passage in the pressure relief valve between the inlet and the outlet is closed by a valve disc of the pressure relief valve, which forms a seal against a valve seat of the pressure relief valve.

[0004] The valve disk preferably has two parts, each of which is preferably disc-shaped. The first of these parts rests against the valve seat when the pressure relief valve is closed, thus separating a high-pressure side, which faces the interior of the tank and to which the pressure from the interior of the tank is applied, from a low-pressure side, which faces the outlet of the pressure relief valve. The second part of the valve disk is connected to the first part, for example via a rod or a pin, and closes an opening between the outlet of the pressure relief valve and the main valve chamber when the pressure relief valve is closed. In other embodiments, it is connected to a diaphragm for actuation. The main valve chamber and the two parts of the valve disk are arranged such that the valve disk must be moved towards the main valve chamber to open the pressure relief valve.This means that the first part must be moved towards the low-pressure side and thus against the force resulting from the pressure difference.

[0005] The main valve chamber is filled with a filling medium via the filling line. This is usually the medium stored in the tank, so that the pressure in the main valve chamber is preferably the same as in the tank. This means that the pressure difference between the high-pressure side and the low-pressure side is identical for both sections of the valve plate. The low-pressure side is formed by the outlet of the pressure relief valve. The high-pressure side is formed by the interior of the tank in the first section of the valve plate and by the main valve chamber in the second section of the valve plate, both of which are under the same pressure.

[0006] Preferably, the pressurized area of the second portion of the valve disk is larger than the pressurized area of the first portion of the valve disk, so that the valve disk is pressed into the closed position by the resulting force.

[0007] The pilot, also called a pilot valve, is a separate valve that has a force device, for example an elastic element such as a spring, or a magnetic element. The pilot has a pilot chamber that is connected to the control line. The internal pressure of the tank prevails in the control line, which is connected to the interior of the tank. The pilot is opened when a pressure difference between the ambient pressure (atmosphere) and the pressure prevailing in the control line exceeds the set pressure, so that the force applied by the force device is overcome. By opening the pilot, the main valve chamber is relieved, so that the pressure difference between the high-pressure side and the low-pressure side of the second portion of the valve disk is reduced and is preferably zero.The entire valve disc is then moved into the open position by the pressure difference at the first part of the valve disc and the pressure relief valve is opened.

[0008] A disadvantage is that contamination and resublimation, for example of sulfur, can occur in the filling line, which carries the medium from inside the tank to transfer the pressure and fill the main valve chamber. This impairs valve function and can even lead to blockages. In the case of low-boiling gaseous media stored in the tank and with which the main valve chamber is filled, condensation of the medium can also occur in the main valve chamber. This makes it significantly more difficult to expel the medium from the main valve chamber when the valve is opened due to the resulting increased density of the medium.

[0009] The object of the invention is to eliminate or at least mitigate these disadvantages.

[0010] The invention achieves the stated object by a tank system of the type described above, which is characterized in that the tank system has a control system which is designed to control the flushing pressure in the filling line and / or in the control line such that the flushing pressure is greater than the pressure inside the tank by a predetermined value.

[0011] The filling line connects the reservoir to the main valve chamber. This allows the main valve chamber to be filled with the flushing medium, such as compressed air or nitrogen, thus preventing condensation of the medium used to fill the main valve chamber. The flushing medium is preferably a gas, such as air or nitrogen, or the medium stored in the tank.

[0012] The flushing pressure can assume different values in the filling line and the control line. The flushing pressure in the control line is preferably greater than the actual tank pressure, i.e. the pressure prevailing in the tank of the tank system. This ensures that the control line is actually flushed by the flushing medium. The tank of the tank system has a maximum tank working pressure, which is the maximum that can or may prevail in the tank before measures must be taken to counteract a further increase in pressure. The flushing pressure in the control line is preferably selected so that it is greater than the maximum tank working pressure. The flushing pressure in the control line is preferably selected so that it is lower than the response pressure at which the pilot is opened. This ensures that the pilot and thus also the pressure relief valve are not accidentally opened by the flushing medium under the flushing pressure.

[0013] The flushing pressure in the filling line is preferably greater than the actual tank pressure, i.e. the pressure prevailing in the tank of the tank system. This ensures that the filling line is actually flushed by the flushing medium. The tank of the tank system has a maximum tank working pressure, which is the maximum that can or may prevail in the tank before measures must be taken to counteract a further increase in pressure. The flushing pressure in the filling line is preferably selected so that it is greater than the maximum tank working pressure. The flushing pressure in the filling line is not upper limited by the set pressure of the pilot. The flushing pressure in the filling line is preferably greater than the set pressure. The greater the flushing pressure in the filling line, the greater the pressure prevailing in the main valve chamber and thus the force acting on the second part of the valve disk.Since the flushing pressure is preferably greater than the actual tank pressure acting on the first part of the valve plate, this design ensures a high closing force and therefore a particularly safe and tightly closed pressure relief valve. The flushing pressure in the filling line is limited upwards by the stability of the components subjected to the flushing pressure.

[0014] Preferably, the flushing pressure is at least 90%, preferably at least 93%, particularly preferably at least 96% of the response pressure.

[0015] The reservoir preferably comprises a closed container, for example a pressure vessel, container or tank, in which the flushing medium is stored under a storage pressure. The storage pressure is preferably higher than the flushing pressure, so that preferably as much of the flushing medium as possible is stored in the reservoir. Alternatively or additionally, the reservoir has at least one supply line through which flushing medium is provided, preferably continuously. Preferably, the reservoir is connected to the filling line via a flushing line. This is particularly useful if the filling line connects the tank to the main valve chamber. In this case, the main valve chamber can be filled with both the flushing medium and the medium from the tank. Preferably, a valve, for example a switching valve, is provided by which switching between the two options can be carried out.

[0016] Alternatively or additionally, the reservoir is connected to the filling line via a flushing line and the filling line is connected to the control line via a connecting line, wherein a check valve is preferably arranged in the connecting line, which allows flow from the filling line into the control line and prevents backflow from the control line into the filling line. This arrangement fills the main valve chamber with the flushing medium and is therefore subject to the flushing pressure regardless of the pressure inside the tank. If the flushing pressure is higher than the internal pressure of the tank, this arrangement ensures a higher closing force because a pressure difference between the atmosphere and the internal tank pressure acts on the first part of the valve disk in the direction of the open position and a larger pressure difference between the atmosphere and the flushing pressure acts on the second part of the valve disk in the direction of the closed position.Flushing medium is also introduced into the control line through the connecting line, so that the control line is also flushed.

[0017] The control line preferably connects the interior of the tank to the pilot. Preferably, between these two ends of the control line, the control line is connected to a flushing line through which the flushing medium can be introduced into the control line. This connection point is preferably located as far as possible toward the pilot valve, preferably less than 20 cm, particularly preferably less than 10 cm, and most preferably less than 5 cm from the pilot.

[0018] The flushing medium is introduced into the control line under a flushing pressure. This flushing pressure is preferably only slightly lower than the set pressure. It is therefore usually greater than the pressure prevailing in the tank. In these cases, the medium in the control line is therefore forced out of the control line and into the tank by the flushing medium. The flushing pressure then prevails in the control line, which is greater than the internal tank pressure, so that the control line is flushed by the flushing medium, at least in the section between the point where the flushing medium enters the control line and the tank.

[0019] This means that the flushing medium in this section flows through the control line, rather than standing in it, as is common in the prior art. This prevents or at least reduces buildup, contamination, and resublimation. Furthermore, the prevailing flushing pressure is lower than the set pressure of the pilot, preventing accidental opening of the pilot and thus the pressure relief valve.

[0020] If the pressure within the tank rises to a value greater than the flushing pressure, the medium in the tank is forced into the control line, and this internal tank pressure then prevails in the control line. If this pressure rises above the set pressure, the pilot opens as in the prior art, relieving the pressure in the main valve chamber and opening the pressure relief valve. As long as the internal tank pressure is greater than the flushing pressure, the control line is not flushed; instead, the medium it contains remains in the control line.

[0021] To ensure that this only occurs for as short a period as possible, the flushing pressure is preferably only slightly lower than the response pressure.

[0022] In a preferred embodiment, the reservoir is connected to the control line via a flushing line. The flushing medium is fed into the control line through this flushing line. A check valve, also called a one-way valve, is preferably arranged in the flushing line. It allows the flushing medium to flow from the reservoir into the control line and prevents backflow from the control line into the reservoir.

[0023] Preferably, the pressurized surfaces of the first portion of the valve plate and the second portion of the valve plate are selected such that even if the internal tank pressure is greater than the flushing pressure but less than the response pressure, a sufficiently large closing force acts on the valve plate to keep the pressure relief valve securely closed.

[0024] The filling line preferably has a valve that can be brought into a first state and a second state. If the valve is in the first state, the main valve chamber can be filled with the flushing medium. If the valve is in the second state, the main valve chamber can be filled with the medium located in the tank. This valve can therefore be used to switch between filling from the reservoir and filling from the tank. This is particularly advantageous if a closed volume is used as a reservoir that, for example, needs to be replaced or refilled. The valve is preferably preloaded towards the second state. A spring is provided for this purpose, for example.

[0025] In a preferred embodiment, the valve arrangement has a pressure reducer which reduces the pressure of the flushing medium to the flushing pressure. The pressure reducer is preferably arranged in the connecting line, the flushing line or the filling line. In a particularly preferred embodiment, the valve arrangement has several pressure reducers. Particularly preferably, a first pressure reducer is provided, which is arranged, for example, in the flushing line or in the filling line and which specifies the magnitude of the flushing pressure in the filling line and thus also in the main valve chamber. Preferably, a further pressure reducer is provided, which is arranged, for example, in the control line, particularly preferably in the connecting line and specifies the flushing pressure in the control line. In this way, the flushing pressure in the filling line and the flushing pressure in the control line can be adjusted separately and independently of one another.Preferably, the flushing pressure in the control line is lower than the flushing pressure in the filling line.

[0026] The invention solves the stated problem by a valve arrangement for a tank system of the type described here. The valve arrangement has a pilot-controlled pressure relief valve with a main valve chamber, a filling line, a pilot and a control line, and also has a reservoir filled with a flushing medium and is designed to guide the flushing medium into the filling line at a flushing pressure, wherein the flushing pressure is less than the response pressure.

[0027] Some embodiments of the present invention are explained in more detail below with the aid of the attached figures. They show: Fig. 1 - a schematic representation of a part of a tank system according to the state of the art and Fig. 2 to 15 - schematic representations of tank systems according to different embodiments of the present invention.

[0028] Fig. 1 shows a section of a tank system according to the prior art. It has a tank 2, which in the illustrated embodiment is double-walled, and a valve arrangement with a pressure relief valve 4. The pressure relief valve 4 has a valve plate comprising a first portion 6 and a second portion 8. The first portion 6 is arranged between an inlet 12 of the pressure relief valve 4 and an outlet 14 of the pressure relief valve 4. In the illustrated closed state, the second portion 8 separates the outlet 14 of the pressure relief valve 4 from its main valve chamber 10. The pilot 16 is shown above the main valve chamber 10.

[0029] A control line 18 connects the pilot 16 to the tank 2 and transmits the pressure prevailing in the tank 2 to the pilot 16. The tank system also has a filling line 22 that connects the tank 2 to the main valve chamber 10. If the pressure in the tank 2 exceeds a predetermined set pressure, the pilot 16 opens and the main valve chamber 10 is relieved, i.e., the pressure within the main valve chamber 10 is reduced to the atmospheric pressure prevailing outside the system. This opens the pressure relief valve, and the valve disk with the first portion 6 and the second portion 8 is moved to the open position.

[0030] Fig. 2 shows an embodiment of a tank system according to a first exemplary embodiment of the present invention. Unlike the prior art system, the filling line 22 is not connected to the tank 2, but to a reservoir 20, which in the illustrated exemplary embodiment is designed as a supply line. Via this reservoir 20, a filling medium is supplied to the system through a check valve 28, which is introduced into the filling line 22. Located in the filling line 22 is a pressure reducer 26, by which the pressure of the filling medium flowing from the reservoir 20 is reduced to a flushing pressure that is lower than the response pressure of the valve. In the illustrated exemplary embodiment, the flushing pressure is 3% to 5% below the response pressure. In this configuration, the filling medium flowing from the reservoir 20 is introduced into the main valve chamber 10.

[0031] Fig. Figure 3 shows a different embodiment. Here, the reservoir 20 is not connected to the filling line 22, but rather to the control line 18. In the illustrated embodiment, the control line 18 contains the pressure reducer 26, which reduces the pressure of the filling medium flowing from the reservoir 20 to the flushing pressure, which is lower than the set pressure.

[0032] In Fig. 4 is the design of Fig. 3 has been supplemented by a connecting line 24, through which the control line 18 is connected to the filling line 22. The medium flowing from the reservoir 20, the pressure of which is reduced by the pressure reducer 26, can flow through the connecting line 24 from the control line 18 into the filling line 22 and thus fill the main valve chamber 10. To prevent medium from the tank 2, to which the filling line 22 is connected, from flowing into the control line 18, a check valve 28 is arranged in the connecting line 24.

[0033] Fig. 5 shows a further embodiment in which the reservoir 20 is again connected to the filling line 22. The connecting line 24 connects as in Fig. 4, the filling line 22 with the control line 18. In the connecting line 24, the check valve 28 is again positioned, which in comparison to Fig. 4, however, works in the opposite direction. In Fig. 4, the check valve 28 allows flow from the control line 18 into the filling line 22 and prevents flow in the opposite direction. In Fig. 5, the check valve 28 allows flow from the filling line 22 into the control line 18 and prevents backflow in the opposite direction. In this embodiment, the medium flowing from the reservoir 20 fills the main valve chamber 10 on the one hand and flushes the control line 18 on the other hand, provided the pressure prevailing in the tank 2 is lower than the flushing pressure set by the pressure reducer 26.

[0034] If the pressure in the tank 2 is lower than the flushing pressure, flushing medium is introduced from a reservoir 20, which is designed here as a supply line, via the filling line 22 and a connecting line 24 into the control line 18. The flushing medium passes through a pressure reducer 26, in which the flushing medium is brought to a flushing pressure. In the connecting line 24 is the check valve 28, which allows a flow from the filling line into the control line 18 (in Fig. 5 from left to right) and prevented in the opposite direction.

[0035] Fig. Figure 6 shows another embodiment. The reservoir 20 is now designed as a closed container 30 in addition to the supply line. In addition to the control line 18, the connecting line 24 and the filling line 22, which, unlike in Fig. 5 connects the pilot 16 with the tank 2, the design in Fig. 6 has a flushing line 32 in which the pressure reducer 26 is arranged. In Fig. 6 also shows a valve 34, which is shown in a first state. In this state, the flushing line 32 is connected via the valve 34 to the upper part of the filling line 22, so that the main valve chamber 10 can be filled with the flushing medium from the reservoir 20. The valve 34 is held in this first state via the switching line 36 by the pressure prevailing in the reservoir 20. A spring 39 can be seen, which preloads the valve 34 towards a second state (not shown). When the pressure in the switching line 36 drops and the force thus applied is smaller than the force applied by the spring 39, the valve 34 is brought into the second state, in which the main valve chamber 10 can be filled with the medium from the tank 2. This situation is shown in Fig. 7 and Fig. 8. These two representations differ only in the design of the tank 2, which in Fig. 7 as a double-walled tank and in Fig. 8 is shown as a single-walled tank. In Fig. 9 is in addition to the illustration from Fig. 6 shows a further embodiment of the reservoir 20.

[0036] In Fig. 10 shows that the flushing line 32 is equipped with a pressure sensor 38, by which the pressure within the flushing line 32 can be determined. The signals generated by the pressure sensor 38 are used to control the valve 34 through the electrical lines 40 shown, which in the Fig. 10 is shown in the first state, so that the main valve chamber 10 is flushed with the play medium. In Fig. Figure 11 shows the reverse case. The signals from sensor 38 have caused valve 34 to be in the second position, so that the main valve chamber 10 is filled with the medium from tank two.

[0037] In Fig. 12 shows a further pressure reducer 26 in the connecting line 24. The pressure of the medium flowing through the flushing line 32 is reduced by the first pressure reducer 26, which is located in the flushing line 32, to a first pressure that is lower than the set pressure. The main valve chamber 10 is filled with this pressure. It may be advisable not to use this pressure to flush the control line 18, but rather to use the flushing pressure for this purpose. Therefore, the second pressure reducer 26 is present in the connecting line 24, which brings the medium flowing through the connecting line 24 to the desired flushing pressure.

[0038] In Fig. 13 shows a backwash line 42 in which there is another check valve 28. Through this backwash line 42, the medium flowing through the flushing line 32 and the valve 34 into the filling line 22 is also directed into tank two, so that this part of the filling line 22 can also be flushed. Fig. 14, two valves 34 are connected in series to increase the redundancy and thus the safety of the system.

[0039] Fig. 15 corresponds to the representation from Fig. 12, which also contains the backwash line 42. The backwash pressure generated by the second pressure reducer 26, which also exists in the control line, prevails in this line. List of reference symbols: 2 tanks 4 pressure relief valve 6 first share 8 second share 10 Main valve chamber 12 Inlet 14 Procedure 16 pilots 18 Control line 20 reservoirs 22 Filling line 24 connecting line 26 pressure reducers 28 Check valve 30 containers 32 Flushing line 34 Valve 36 Switching line 38 Pressure sensor 39 spring 40 electrical cables 42 Backwash line

Claims

[1] Tank system comprising a tank (2) and a valve arrangement with a pilot-controlled pressure relief valve (4), wherein the pressure relief valve (4) - a main valve chamber (10), - a filling line (22), - a pilot (16) and - a control line (18), wherein the main valve chamber (10) is connected to the filling line (22) and can be filled with a filling medium via the latter, and wherein the control line (18) is connected to the tank (2) and the pilot (16) in such a way that the pilot (16) is opened when a pressure in the control line (18) exceeds a predetermined response pressure, whereby the pressure relief valve (4) is opened, wherein the valve arrangement has a reservoir (20) filled with a flushing medium, wherein the valve arrangement is designed to conduct the flushing medium at a flushing pressure into the control line (18) and / or into the filling line (22), characterized bythat the tank system has a control system which is designed to control the flushing pressure in the filling line (22) and / or in the control line (18) such that the flushing pressure is greater than the pressure inside the tank (2) by a predetermined value. [2] Tank system according to claim 1, characterized by that the flushing pressure in the control line (18) is lower than the response pressure. [3] Tank system according to claim 1 or 2, characterized by that the flushing pressure is at least 90%, preferably at least 93%, particularly preferably at least 96% of the response pressure. [4] Tank system according to one of the preceding claims characterized by that the flushing pressure in the filling line (22) is greater than the response pressure. [5] Tank system according to one of the preceding claims, characterized by that the reservoir (20) is connected to the filling line (22) via a flushing line (32). [6] Tank system according to one of the preceding claims, characterized bythat the filling line (22) is connected to the control line (18) via a connecting line (24), wherein a check valve (28) is arranged in the connecting line (24) which allows flow only from the filling line (22) into the control line (18). [7] Tank system according to claim 6, characterized by that the filling line (22) has a valve (34) which can be brought into a first state in which the main valve chamber (10) can be filled with flushing medium, and into a second state in which the main valve chamber (10) can be filled with a medium which is located in the tank (2). [8] Tank system according to one of the preceding claims, characterized by that the valve arrangement has a pressure reducer (26) which reduces the pressure of the flushing medium to the flushing pressure. [9] Valve arrangement and control for a tank system according to one of the preceding claims, which has a pilot-controlled pressure relief valve (4) with a main valve chamber (10), a filling line (22), a pilot (16) and a control line (18), and has a reservoir (20) filled with a flushing medium and is designed to conduct the flushing medium into the control line (18) at a flushing pressure, the flushing pressure being less than the response pressure.

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