Tank system and valve assembly

Abstract

The invention relates to a tank system having a tank (2) and a valve assembly with a pilot-controlled pressure relief valve (4). The pressure relief valve (4) has a main valve chamber (10), a filling line (22), a pilot device (16) and a control line (18). The main valve chamber (10) is connected to a filling line (22) and can be filled with a filling medium via the filling line. The control line (18) is connected to the tank (2) and the pilot device (16) such that the pilot device (16) opens when the pressure in the control line (18) exceeds a predetermined response pressure, thereby opening the pressure relief valve (4). The valve assembly has a reservoir (20) filled with a flushing medium, which valve assembly is arranged to introduce the flushing medium into the control line (18) and / or the filling line (22) at a flushing pressure. The invention also relates to a valve assembly for a tank system.

Description

Technical Field

[0001] The present invention relates to a storage tank system, which has a storage tank and a valve assembly with a pilot-controlled pressure relief valve, wherein the pressure relief valve has a main valve chamber, a filling pipeline, a pilot device and a control pipeline, wherein the main valve chamber is connected to the filling pipeline and can be filled with a filling medium through the filling pipeline, and the control pipeline is connected to the storage tank and the pilot device in such a way that when the pressure in the control pipeline exceeds a predetermined response pressure, the pilot device is opened, thereby causing the pressure relief valve to be opened. The present invention also relates to a valve assembly for such a storage tank system. Background Art

[0002] Tank systems of the type mentioned above and valve assemblies of this type are already known in the prior art. For example, large quantities of oil or gas are stored in such tank systems, which are also used to store liquid or gaseous chemicals. However, filling and emptying as well as temperature differences can lead to an expansion of the medium stored in the tanks of the tank system, which results in an increase in the pressure in the tanks. It is important to prevent excessive pressure, which could damage the tanks and prevent the contained medium from escaping uncontrolled into the environment.

[0003] In order to be able to reduce the pressure in the tank in a controlled manner in this case, a valve assembly with a pressure relief valve is used. The actual pressure relief valve has an inlet connected to the tank and an outlet connected to a pipeline, through which the medium escaping from the tank through the pressure relief valve can be discharged. In the closed state of the pressure relief valve, the passage between the inlet and the outlet of the pressure relief valve is closed by the valve disc of the pressure relief valve, which is in sealing contact with the valve seat of the pressure relief valve.

[0004] The valve disc preferably has two parts, each of which is preferably configured in a disc shape. The first part rests on the valve seat in the closed state of the pressure relief valve, thereby separating the high-pressure side from the low-pressure side, the high-pressure side facing the interior of the tank and the pressure inside the tank acting on the high-pressure side, and the low-pressure side facing the outlet of the pressure relief valve. The second part of the valve disc is connected to the first part, for example, by a rod or a pin, and closes the opening between the outlet of the pressure relief valve and the main valve chamber in the closed state of the pressure relief valve. In other embodiments, it is connected to a diaphragm for manipulation. The main valve chamber and the two parts of the valve disc are arranged so that the valve disc must move in the direction of the main valve chamber to open the pressure relief valve. This means that the first part must move in the direction of the low-pressure side and thereby resist the force caused by the pressure difference.

[0005] The main valve chamber is filled with a filling medium via a filling line. This filling medium is usually a medium stored in a tank, so that the pressure prevailing 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 for both parts of the valve disc is the same. The low-pressure side is formed by the outlet of the pressure relief valve. The high-pressure side is formed in the first part of the valve disc by the interior of the tank and in the second part of the valve disc by the main valve chamber, both of which are at the same pressure.

[0006] The pressure surface of the second part of the valve disk is preferably larger than the pressure surface of the first part of the valve disk, so that the valve disk is pressed into the closed position by the force generated thereby.

[0007] The pilot device, also called a pilot valve, is an independent valve having a force device, which has, for example, an elastic element (such as a spring) or a magnetic element. The pilot device has a pilot chamber connected to the control line. In the control line connected to the interior of the tank, the internal pressure of the tank is dominant. When the pressure difference between the ambient pressure (atmosphere) and the pressure in the control line exceeds the response pressure, the pilot device is opened so that the force applied by the force device is overcome. By opening the pilot device, the main valve chamber is unloaded, so that the pressure difference between the high-pressure side and the low-pressure side of the second part of the valve disc is reduced, preferably to zero. Then, the entire valve disc is moved to the open position by the pressure difference of the first part of the valve disc and the pressure relief valve is opened.

[0008] The disadvantage is that contamination and resublimation, for example of sulfur, may occur in the filling line, in which medium from the inside of the tank is present in order to transmit pressure and fill the main valve chamber. This can impair valve function and even lead to blockages. If low-boiling gaseous media are stored in the tank and the main valve chamber is filled with this low-boiling gaseous media, this can also lead to condensation of the medium in the main valve chamber. Therefore, when the valve is opened, the increase in medium density greatly increases the difficulty of discharging the medium from the main valve chamber. Summary of the invention

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

[0010] The invention achieves this object by means of a tank system of the type mentioned above, which is characterized in that the valve assembly has a reservoir filled with a flushing medium, wherein the valve assembly is arranged so that the flushing medium is introduced into the filling line and / or the control line at a flushing pressure, wherein the flushing pressure is lower than the response pressure.

[0011] The filling pipeline connects the reservoir and the main valve chamber. Therefore, a flushing medium, such as compressed air or nitrogen, can be filled into the main valve chamber to prevent the medium filled in the main valve chamber from condensing. The flushing medium is preferably a gas, such as air or nitrogen, or a medium stored in a storage tank.

[0012] The flushing pressure can have different values ​​in the filling line and in the control line. The flushing pressure in the control line is preferably greater than the actual tank pressure, i.e. the pressure in the tank of the tank system. This ensures that the control line is actually flushed with the flushing medium. The tanks of the tank system have a maximum tank working pressure, which is the maximum pressure that can or is allowed to exist in the tank before measures are taken to prevent a further increase in pressure. The flushing pressure in the control line is preferably selected to be greater than the maximum tank working pressure. The flushing pressure in the control line is preferably selected so that it is below the response pressure at which the pilot device opens. This ensures that the pilot device and the pressure relief valve are not opened inadvertently by the flushing medium at the flushing pressure.

[0013] The flushing pressure in the filling line is preferably greater than the actual tank pressure, i.e. the pressure in the tank of the tank system. This ensures that the filling line is actually flushed with the flushing medium. The tank of the tank system has a maximum tank working pressure, which is the maximum pressure that can or is allowed to exist in the tank before measures are taken to prevent 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 limited upward by the response pressure of the pilot device. The flushing pressure in the filling line is preferably greater than the response pressure. The greater the flushing pressure in the filling line, the greater the pressure in the main valve chamber and therefore the greater the force acting on the second part of the valve disc. Since the flushing pressure is preferably greater than the actual tank pressure acting on the first part of the valve disc, this configuration ensures a high closing force, so that the pressure relief valve is particularly safe and can also be closed particularly tightly. The flushing pressure in the filling line is limited upward by the stability of the component to which the flushing pressure is applied.

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

[0015] The reservoir preferably has a closed container, such as a pressure vessel, a container or a tank, in which the flushing medium is stored under a storage pressure. The storage pressure is preferably higher than the flushing pressure, so that as much flushing medium as possible can be stored in the reservoir. Alternatively or additionally, the reservoir has at least one supply line, via which the flushing medium is preferably continuously supplied. The reservoir is preferably connected to a 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 not only with flushing medium, but also with medium from the tank. Preferably, a valve is provided, such as a switching valve, by which it is possible to switch between the two possibilities.

[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 non-return valve is preferably arranged in the connecting line, which allows a flow from the filling line to the control line and prevents a backflow from the control line to the filling line. Due to this arrangement, the main valve chamber is filled with flushing medium and is therefore subject to the flushing pressure regardless of the pressure in the tank. If the flushing pressure is higher than the pressure in the tank, this arrangement ensures a higher closing force, since the pressure difference between the atmospheric pressure and the tank pressure acts on the first part of the valve disc in the direction of the open position, while the greater pressure difference between the atmospheric pressure and the flushing pressure acts on the second part of the valve disc in the direction of the closed position. In addition, flushing medium also enters the control line via 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 device. Between the two ends of the control line, the control line is preferably connected to a flushing line, via which a flushing medium can be introduced into the control line. This connection point is preferably located as far as possible in the direction of the pilot device, preferably less than 20 cm, particularly preferably less than 10 cm, most preferably less than 5 cm from the pilot device.

[0018] The flushing medium enters the control line at a flushing pressure. The flushing pressure is preferably only slightly lower than the response pressure. Therefore, it is usually greater than the pressure in the tank. In this case, the medium in the control line is pressed out of the control line and into the tank by the flushing medium. At this time, the flushing pressure in the control line is greater than the internal pressure of the tank, so that the control line is flushed with the flushing medium at least in the section between the flushing medium entering the control line and the tank. This means that the flushing medium flows through the control line in this section instead of staying in the control line as is common in the prior art. This can prevent or at least reduce adhesion, contamination and resublimation. On the other hand, the prevailing flushing pressure is lower than the response pressure of the pilot device, so that accidental opening of the pilot device and thus of the pressure relief valve can be avoided.

[0019] If the pressure inside the tank rises to a value greater than the flushing pressure, the medium in the tank is pressed into the control line, whereupon the pressure inside the tank becomes dominant. If this pressure is higher than the response pressure, the pilot device opens as in the prior art, thereby unloading the main valve chamber and opening the pressure relief valve. As long as the pressure inside the tank is greater than the flushing pressure, the control line is not flushed, but the medium contained therein remains in the control line.

[0020] In order to ensure that this situation lasts only as short a time as possible, the flushing pressure is preferably only slightly lower than the response pressure.

[0021] In a preferred configuration, the reservoir is connected to the control line via a flushing line. The flushing medium enters the control line via the 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 a backflow from the control line to the reservoir.

[0022] Preferably, the pressure surfaces of the first and second parts of the valve disc are selected so that even when the pressure in the tank is greater than the flushing pressure but less than the response pressure, there will be a sufficiently large closing force on the valve disc to ensure that the pressure relief valve is safely closed.

[0023] The filling line preferably has a valve that can be brought into a first state and into 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 from the tank. Thus, the valve can be used to switch between filling with medium from a reservoir and filling with medium from the tank. This is particularly advantageous, for example, if the enclosed volume is used as a reservoir that, for example, has to be replaced or refilled. The valve is preferably preloaded in the direction of the second state. For example, a spring can be provided for this purpose.

[0024] In a preferred configuration, the valve assembly has a pressure reducer that can reduce 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 configuration, the valve assembly has a plurality of pressure reducers. Particularly preferably, there is a first pressure reducer, which is arranged, for example, in the flushing line or the filling line, and which determines the size of the flushing pressure in the filling line and therefore also determines the size of the flushing pressure in the main valve chamber. Preferably, there are also other pressure reducers, which are arranged, for example, in the control line, particularly preferably in the connecting line, and are used to predetermine 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 set separately and independently of each other. Preferably, the flushing pressure in the control line is lower than the flushing pressure in the filling line.

[0025] The invention achieves the stated object by a valve assembly for a tank system of the type described herein, the valve assembly having a pilot-controlled pressure relief valve with a main valve chamber, a filling line, a pilot device and a control line, the valve assembly also having a reservoir filled with a flushing medium and being arranged to introduce the flushing medium into the filling line at a flushing pressure, wherein the flushing pressure is responsive to pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Some embodiments of the present invention are described in more detail below with the help of the accompanying drawings. In the accompanying drawings:

[0027] Figure 1 A schematic diagram showing a portion of a storage tank system according to the prior art, and

[0028] Figures 2 to 15 Schematic diagrams showing tank systems according to various embodiments of the present invention. DETAILED DESCRIPTION

[0029] Figure 1 A section of a tank system according to the prior art is shown. The tank system has a tank 2 and a valve assembly with a pressure relief valve 4, which is designed in a double-walled manner in the illustrated embodiment. The pressure relief valve 4 has a valve disc, which comprises a first part 6 and a second part 8. The first part 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 closed state shown, the second part 8 separates the outlet 14 of the pressure relief valve 4 from the main valve chamber 10 of the pressure relief valve. A pilot device 16 is shown above the main valve chamber 10.

[0030] The control line 18 connects the pilot device 16 with the tank 2 and transmits the pressure in the tank 2 to the pilot device 16. The tank system also has a filling line 22, which connects the tank 2 with the main valve chamber 10. If the pressure in the tank 2 exceeds a predetermined response pressure, the pilot device 16 is opened and the main valve chamber 10 is depressurized, that is, the pressure in the main valve chamber 10 is reduced to the atmospheric pressure outside the system. As a result, the pressure relief valve is opened and the valve disc with the first part 6 and the second part 8 is moved to the open position.

[0031] Figure 2 An implementation of a tank system according to a first embodiment of the present invention is shown. Unlike the systems of the prior art, the filling line 22 is not connected to the tank 2, but to the reservoir 20, which is designed as a supply line in the illustrated embodiment. Via the reservoir 20, the filling medium introduced into the filling line 22 is supplied to the system through a check valve 28. The filling line 22 has a pressure reducer 26, by which the pressure of the filling medium flowing out of the reservoir 20 can be reduced to a flushing pressure that is lower than the valve response pressure. In the illustrated embodiment, the flushing pressure is 3% to 5% lower than the response pressure. In the present configuration, the filling medium flowing out of the reservoir 20 is introduced into the main valve chamber 10.

[0032] Figure 3 A different configuration is shown. Here, the reservoir 20 is not connected to the filling line 22, but to the control line 18. In the embodiment shown in the figure, a pressure reducer 26 is provided in the control line to reduce the pressure of the filling medium flowing out of the reservoir 20 to a flushing pressure below the response pressure.

[0033] exist Figure 4 middle, Figure 3The configuration in FIG. 1 further adds a connecting line 24, through which the control line 18 is connected to the filling line 22. After the pressure of the medium flowing out of the reservoir 20 is reduced by the pressure reducer 26, it can flow from the control line 18 into the filling line 22 through the connecting line 24, thereby filling the main valve chamber 10. In order to prevent the medium from flowing from the storage tank 2 connected to the filling line 22 into the control line 18, a check valve 28 is arranged in the connecting line 24.

[0034] Figure 5 Another configuration is shown, in which the reservoir 20 is again connected to the flushing line 22. Figure 4 As shown, the connecting line 24 connects the filling line 22 to the control line 18. The check valve 28 is located in the connecting line 24, but is Figure 4 Compared with , its action direction is opposite. Figure 4 In the embodiment, the check valve 28 allows flow from the control line 18 to the filling line 22 and prevents reverse flow. Figure 5 In the embodiment, the check valve 28 allows the flow from the filling line 22 to flow into the control line 18 and prevents reverse backflow. In this configuration, the medium flowing out of the reservoir 20 fills the main valve chamber 10 on the one hand and flushes the control line 18 on the other hand, provided that the pressure in the tank 2 is lower than the flushing pressure set by the pressure reducer 26.

[0035] If the pressure in the tank 2 is lower than the flushing pressure, the flushing medium will flow from the reservoir 20 (which is designed as a supply line here) through the filling line 22 and the connecting line 24 into the control line 18. The flushing medium flows through the pressure reducer 26, in which the flushing medium reaches the flushing pressure. A non-return valve 28 is located in the connecting line 24, which allows flow from the filling line to the control line 18 ( Figure 5 from left to right in the center) and prevent reverse flow.

[0036] Figure 6 Another embodiment is shown. The reservoir 20 is now designed as a sealed container 30 in addition to the supply line. Figure 5 The difference is that, in addition to the control line 18, the connecting line 24 and the filling line 22 connecting the pilot device 16 to the tank 2, Figure 6 The arrangement in FIG. 2 also has a flushing line 32 , in which the pressure reducer 26 is arranged. Figure 6Also shown is a valve 34, which is shown in a first state. In this state, the flushing line 32 is connected to the upper part of the filling line 22 via the valve 34, so that the main valve chamber 10 can be filled with flushing medium from the reservoir 20. The valve 34 is kept in the first state by the pressure in the reservoir 20 via the switching line 36. A spring 39 can be seen, which preloads the valve 34 in the direction of the second state, which is not shown. When the pressure in the switching line 36 drops and the force applied is less than the force applied by the spring 39, the valve 34 enters the second state, in which the main valve chamber 10 can be filled with medium from the tank 2. Figure 7 and Figure 8 The two figures differ only in the configuration of tank 2. Figure 7 The storage tank in is a double-walled storage tank, and Figure 8 The tanks in are single-wall tanks. Figure 6 In addition to the icons in Fig. 9 Another configuration of the storage tank 20 is shown.

[0037] Fig.10 As shown, the flushing line 32 is equipped with a pressure sensor 38, by which the pressure in the flushing line 32 can be determined. The signal generated by the pressure sensor 38 is used to control the flushing line 32 via the electrical pipeline 40 shown in the figure. Fig.10 The valve 34 is in the first state, thereby flushing the main valve chamber 10 with the flushing medium. Fig.11 The reverse situation is shown: the signal of the sensor 38 causes the valve 34 to be in the second position, so that the main valve chamber 10 is filled with the medium of the tank 2 .

[0038] Fig.12 A further pressure reducer 26 is shown in the connecting line 24. The pressure of the medium flowing through the flushing line 32 is reduced by the first pressure reducer 26 located in the flushing line 32 to a first pressure which is below the response pressure. The main valve chamber 10 is filled with this pressure. It may be sensible not to use this pressure to flush the control line 18, but to use the flushing pressure for flushing. Therefore, there is a second pressure reducer 26 in the connecting line 24, which puts the medium flowing through the connecting line 24 at the required flushing pressure.

[0039] Fig.13 A backwash line 42 is shown, in which a further non-return valve 28 is provided. Via this backwash line 42, the medium flowing through the flushing line 32 and the valve 34 into the filling line 22 is also introduced into the tank 2, so that this part of the filling line 22 can also be flushed. Fig.14 In the embodiment, two valves 34 are connected in series to increase redundancy, thereby improving the safety of the system.

[0040] Fig.15 and Fig.12 , in which there is also an additional backwash line 42. The flushing pressure generated by the second pressure reducer 26 prevails in this backwash line, which flushing pressure also prevails in the control line.

[0041] List of reference numerals:

[0042] 2 Storage tanks

[0043] 4 Pressure relief valve

[0044] 6 Part 1

[0045] 8 Part 2

[0046] 10 Main valve chamber

[0047] 12 Entrance

[0048] 14 Exit

[0049] 16 Pilot device

[0050] 18 Control line

[0051] 20 Storage

[0052] 22 Filling line

[0053] 24 Connecting pipes

[0054] 26 Pressure reducer

[0055] 28 Check valve

[0056] 30 Containers

[0057] 32 Flushing pipes

[0058] 34 valve

[0059] 36 Switching lines

[0060] 38 Pressure Sensor

[0061] 39 Spring

[0062] 40 Electrical pipeline

[0063] 42 Backwash line.

Claims

1. A storage tank system, comprising a storage tank (2) and a valve assembly with a pilot-controlled pressure relief valve (4), wherein the pressure relief valve (4) has: - Main valve chamber (10); - filling line (22); - a pilot device (16); and - control line (18), wherein the main valve chamber (10) is connected to the filling pipeline (22) and can be filled with a filling medium via the filling pipeline, wherein the control pipeline (18) is connected to the storage tank (2) and the pilot device (16), so that when the pressure in the control pipeline (18) exceeds a predetermined response pressure, the pilot device (16) opens, thereby causing the pressure relief valve (4) to open, It is characterized in that The valve assembly has a reservoir (20) filled with a flushing medium, wherein the valve assembly is configured to introduce the flushing medium at a flushing pressure into the control line (18) and / or the filling line (22).

2. The storage tank system according to claim 1, characterized in that: The flushing pressure in the control line (18) is lower than the response pressure.

3. The storage tank system according to claim 1 or 2, characterized in 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 in that The flushing pressure in the filling pipeline (22) is greater than the response pressure.

5. Tank system according to one of the preceding claims, characterized in that The tank system has a control device which is arranged to control the flushing pressure in the filling line (22) and / or in the control line (18) so that the flushing pressure is greater than the pressure inside the tank (2) by a predetermined value.

6. Tank system according to one of the preceding claims, characterized in that The reservoir (20) is connected to the filling line (22) via a flushing line (32).

7. Tank system according to one of the preceding claims, characterized in that The filling line (22) is connected to the control line (18) via a connecting line (24), wherein a non-return valve (28) is arranged in the connecting line (24) and only allows a flow from the filling line (22) to the control line (18).

8. The storage tank system according to claim 7, characterized in 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 a flushing medium, and a second state, in which the main valve chamber (10) can be filled with a medium present in the tank (2).

9. Tank system according to one of the preceding claims, characterized in that The valve assembly has a pressure reducer (26) which reduces the pressure of the flushing medium to the flushing pressure.

10. A valve assembly for a tank system according to one of the preceding claims, comprising a pilot-controlled pressure relief valve (4) with a main valve chamber (10), a filling line (22), a pilot device (16) and a control line (18), and having a reservoir (20) filled with a flushing medium and being arranged to introduce the flushing medium into the control line (18) at a flushing pressure, wherein the flushing pressure is less than a response pressure.

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