Device and method for filling a tank

Abstract

A device for filling a tank with a product, in particular a liquefied gas product, comprising an upper filling valve that can be arranged on a first filling line connecting a product reservoir to an upper filling opening of the tank, and a lower filling valve that can be arranged on a second filling line connecting the product reservoir to a lower filling opening of the tank, wherein the device includes a control valve at which the tank pressure in the tank is applied as the control variable, and which is connected to the upper filling valve via a first control line and to the lower filling valve via a second control line, wherein the control valve actuates the upper filling valve and the lower filling valve for filling the tank such that the tank pressure corresponds to a predetermined setpoint or setpoint range. The invention also relates to a method for filling a tank.

Description

[0001] The invention relates to a device and a method for filling a tank with a product, in particular a liquefied gas product, comprising an upper filling valve that can be arranged on a first filling line connecting a product reservoir to an upper filling opening of the tank and a lower filling valve that can be arranged on a second filling line connecting the product reservoir to a lower filling opening of the tank.

[0002] For example, cryogenically cooled gases such as LIN, LOX, and LAR are stored in liquid form in tanks. The stored liquefied gas product is then fed into subsequent production or supply processes. This often involves converting the liquefied gas product back into its original gaseous phase, which requires the input of energy, particularly heating. The supply of liquefied gas products to production or supply processes must be very constant and precise, especially because the supplied technical process components have very limited operating ranges for economic or technical reasons.

[0003] A key requirement in this regard is maintaining a product pressure in the storage tank that is as constant as possible at all times, regardless of the tank's operating condition. The pressure in tanks filled with a liquefied gas product is largely determined by the temperature of the gas phase within the tank. Even with very good insulation, the liquefied gas product heats up, which increases the tank pressure and can also significantly alter the pressure when the tank is filled with a colder product. The withdrawal of product from the tank regularly causes a drop in tank pressure, which must also be compensated for. This compensation is typically achieved using heat exchangers to supply energy to the stored product. For economic reasons, the heat exchangers are designed as precisely as possible for typical withdrawal capacities and therefore have only minimal excess capacity beyond the limits of their capacity.

[0004] As previously explained, filling a tank with a product, especially a cold liquefied gas product, leads to a change in tank pressure. Therefore, such tanks are typically filled from both the top and the bottom. When the tank is filled from the top, the tank pressure decreases. Conversely, when the tank is filled from the bottom, the tank pressure increases. This is true unless the filling rate is so high that a jet of liquid is forced through the liquid phase into the gas phase, causing the gas phase to cool significantly and potentially leading to an overall decrease in tank pressure.

[0005] For reasons of economic efficiency and environmental protection, particularly with regard to energy consumption and potential emissions in the supply chain, it is desirable to fill the tank simultaneously from the top and bottom with minimal valve and pipe resistance. Typically, the ratio of the filling rate from the top to the filling rate from the bottom is manually adjusted by an operator to maintain a constant tank pressure. These manual valve adjustments are based on the operator's observations, guided by a pressure gauge reading and a tank marking indicating a nominal working pressure. The operator must continuously monitor the tank pressure and adjust the product flow as needed.At the same time, the operator must monitor and, if necessary, also operate a tank vehicle or similar containing the product reservoir, as well as a pipeline connection between the product reservoir and the tank.

[0006] In this context, extended monitoring gaps across different areas can occur. This results in a significant operator risk and, in practice, a consistent occurrence of operator errors, which can lead to undesirable changes in tank pressure. This, in turn, can cause very substantial economic damage, for example, through prolonged downtime of downstream production or supply processes, or, in the medical sector, disruptions to a critical supply chain.

[0007] Based on the prior art described above, the invention therefore aims to provide a device and a method of the type mentioned at the outset, with which economic damage or disruptions to the supply chain during the filling of a tank with a product can be avoided in a simple and reliable manner.

[0008] The invention solves the problem through independent claims 1 and 15. Advantageous embodiments can be found in the dependent claims, the description and the figures.

[0009] For a device of the type mentioned at the outset, the invention solves the problem in that the device comprises a control valve to which the tank pressure in the tank is applied as the control variable, and which is connected to the upper filling valve via a first control line and to the lower filling valve via a second control line, wherein the control valve actuates the upper filling valve and the lower filling valve to fill the tank in such a way that the tank pressure corresponds to a predetermined setpoint or setpoint range.

[0010] The tank can be a stationary storage tank. It can also be a mobile tank, for example, on a tank truck. The product reservoir containing the product to be filled into the tank can also be a mobile tank, for example, on a tank truck. It can also be a stationary storage tank. As explained, the tank to be filled can be filled with a liquefied gas product, in particular a cryogenic liquefied gas product, such as LIN, LOX, LAR, or LNG. Such a liquefied gas product exists in the tank in both liquid and gaseous phases. The tank can be a single-walled low-temperature or normal-temperature tank, in particular a liquefied gas tank, or a double-walled tank, in particular a liquefied gas tank, for example, a cryogenic tank. The same applies to the product reservoir.

[0011] The device according to the invention comprises a control valve to which the tank pressure during a filling process is applied as the control variable. The control valve is connected to the upper filling valve via a first control line and to the lower filling valve via a second control line, so that the control valve can actuate both the upper and lower filling valves to fill the tank with the product. Actuation is possible with different filling cross-sections, which are released by the respective filling valve. Accordingly, the filling rate of the tank can be individually adjusted from the top and bottom by the control valve. Naturally, the control valve can also close the upper and / or the lower filling valve to completely interrupt the filling process.

[0012] The control valve according to the invention, which in particular forms a pilot valve, is maintenance-free, especially in the long term, and is capable of automatically and precisely maintaining the tank pressure within a nominal operating pressure range or, for example, interrupting further filling as a protective function if a limit value of the tank pressure is exceeded. In particular, the control valve actuates the upper and lower filling valves for filling the tank in such a way that the tank pressure corresponds to a predetermined setpoint or setpoint range, in particular with a defined tolerance above and below a fixed setpoint. To define an acceptable range around the setpoint, a control hysteresis can be specified, which, for example, can be in a range of plus / minus 0.5 bar. This prevents excessively frequent switching of the valves and thus an excessive requirement for a control medium, such as a control gas or control air.

[0013] According to the invention, the control valve can actuate the upper and lower filling valves for simultaneous filling from the top and bottom of the tank, provided the tank pressure applied to the control valve as the controlled variable is within the predetermined setpoint or setpoint range. In this way, the inflow is maximized with minimal resistance. If the tank pressure exceeds the predetermined setpoint or setpoint range, the control valve can, by appropriately actuating the upper and lower filling valves, adjust the tank filling to be concentrated on the top or exclusively from the top. This results in a reduction of the tank pressure.If the tank pressure falls below the specified setpoint or setpoint range, the control valve can actuate the upper and lower filling valves to increase filling from the bottom, for example, exclusively from the bottom, which typically raises the tank pressure again. If the product flow is too rapid, causing an undesirable drop in tank pressure despite exclusive filling through the lower filling valve, the control valve can interrupt further filling. Further filling can then occur, for example, via an external signal bypass, possibly with a reduced flow rate if the lower filling valve is equipped with an external limiter. Alternatively, a reduced bypass filling section can be opened exclusively from the bottom.The control valve automatically resumes normal operation as soon as a minimum tank pressure is reached again.

[0014] It is also possible to add further switching points, for example to achieve a progressively reduced filling from the bottom before the filling process is shut off. This can be accomplished either by means of a slightly open position detection of a valve section or a continuous reduction of the control medium, such as control air, as the differential pressure to a nominal working pressure increases.

[0015] If the tank pressure rises above a maximum pressure despite product being fed exclusively from the top, the control valve can also interrupt further filling from the top. The control valve can then automatically resume normal operation as soon as the maximum pressure is no longer exceeded.

[0016] Overall, the invention enables the avoidance of economic damage caused by prolonged downtime of subsequent production or supply processes or disruptions to a critical supply chain, for example in the medical field, in a reliable and simple manner, by automatically controlling the upper and lower filling valves via the control valve so that the tank pressure does not deviate from a setpoint or setpoint range.

[0017] With a particularly practical design, the control valve can pneumatically actuate the upper and lower filling valves. This allows for especially reliable and fast actuation, potentially independent of a power supply or an external pressure supply.

[0018] The tank pressure can remain in the intermediate tank, and a control pressure for the regulating valve, used for the pneumatic actuation of the upper and lower filling valves, can be supplied from this intermediate tank. The regulating valve can be operated from an external pressure source, such as compressed air, or alternatively with a supplied, pre-maintained tank gas phase. The control gas is used by the regulating valve to actuate the upper and lower filling valves. Particularly when the tank pressure via the intermediate tank is used as the control gas for the regulating valve, it can operate completely autonomously, independent of both a power supply and an external pressure supply. This is especially important for critical infrastructure, for example, in the medical field, such as for supplying hospitals with gases like LOX and LIN.A regulator may be provided that brings the pressure used as control pressure, in particular the pressure supplied from an external pressure source or the tank pressure, to a predetermined constant value for use as control pressure.

[0019] In a further embodiment, the tank pressure applied to the control valve actuates a control shaft of the control valve in the axial direction. Two control elements are arranged on the control shaft, which, depending on the axial position of the control shaft, actuate the upper filling valve and / or the lower filling valve to fill the tank. The control elements can include control discs arranged on the control shaft. The control elements can form cams that, depending on the axial position of the control shaft, actuate, for example, pneumatic valves, which in turn actuate the upper or lower filling valve to fill the tank. The control valve can thus include a cam control for actuating the filling valves. The aforementioned embodiment achieves a particularly simple automatic control of the filling valves.

[0020] In a further embodiment, the control shaft can be provided with an external thread, and the control elements with an internal thread engaging with the external thread, so that the control elements can be arranged on the control shaft in different axial positions. In this way, the control valve can be adjusted to different setpoints or...

[0021] Setpoint ranges can be adjusted. In particular, the integrated spindle function of the shaft and the control elements allows the switching points of the control valve to be variably set.

[0022] In a further design, the tank pressure can actuate the control shaft via a control bellows that expands axially depending on the tank pressure. The elastic control bellows can be made of metal, preferably stainless steel. Such a control bellows can be used, for example, to define a control hysteresis or a setpoint range. The use of a metallic material, such as stainless steel, also has the advantage that such materials are permitted in corresponding pressure equipment, and the design of the control valve is further characterized by a high risk of contamination.

[0023] In a further embodiment, at least one section of the control shaft containing the control elements can be arranged in a housing of the control valve. The housing can form a protective housing. A spring assembly exerting counter-pressure on the control bellows can also be arranged between the control bellows and a section of the control shaft containing the control elements. The spring assembly can be supported on one side by the control bellows and on the other side by the housing. The spring assembly can be formed by a plurality of springs nested one inside the other in a cascade-like arrangement. The control shaft can extend through the spring assembly to the control bellows. The spring assembly can also be a metal spring assembly, preferably a stainless steel spring assembly.The spring assembly, which exerts counter-pressure on the control bellows, allows the control valve to be adjusted, particularly for regulating the tank pressure to a predetermined setpoint range. The design of the spring assembly, consisting of multiple nested or cascaded springs, enables a particularly compact axial design. This offers a significant advantage in the applications at hand. By also manufacturing the spring assembly from a metallic material, such as stainless steel, the advantages described above regarding its suitability for use in pressure devices are achieved. Furthermore, the aforementioned designs allow for a construction in which product-contacting functional areas do not require static or dynamic seals, particularly by combining the flexible control bellows with the aforementioned spring assembly.

[0024] In a further embodiment, an adjusting element can be arranged on the side of the spring assembly facing away from the control bellows, allowing the spring assembly's preload to be adjusted. The adjusting element can include an adjusting screw with which the spring assembly can be compressed to set the preload. This integrated tensioning device allows the control valve to be set to the desired setpoint, particularly by an operator, and, if desired, secured against tampering, for example, by sealing.

[0025] The device may also have a display device on which, for example, the setpoint or setpoint range is displayed for an operator.

[0026] In a further embodiment, the tank pressure can be applied to the control valve via a pressure measuring line. A shut-off valve is arranged in the pressure measuring line, allowing it to be closed off. A test port is provided between the shut-off valve and the control valve, allowing a setpoint pressure to be applied for adjusting the control valve. This embodiment allows the pressure measuring line connecting the tank pressure to the control valve to be shut off, enabling the application of a setpoint or calibration pressure via the test port. In this way, the control valve can be calibrated or adjusted to a specific setpoint or setpoint range independently of the tank and its current pressure.

[0027] The invention also relates to a system comprising a tank for filling with a product, in particular a liquefied gas product, a product reservoir, and a device according to the invention. In the system according to the invention, the upper and lower filling valves are arranged on the first and second filling lines, respectively. As already explained, the tank can be a stationary storage tank and the product reservoir a tank mounted on a tank truck. However, an embodiment is also possible in which the tank is a mobile tank, for example, a tank mounted on a tank truck, and / or in which the product reservoir is a stationary storage tank.

[0028] The invention also solves the problem by a method for filling a tank with a product, in particular a liquefied gas product, using a device or system according to the invention.

[0029] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. They schematically show: Figure 1 shows a system according to the invention with a device according to a first embodiment, Figure 2 shows a control valve of the device according to the invention in a sectional view, and Figure 3 shows a system according to the invention and a device according to a second embodiment.

[0030] Unless otherwise stated, the same reference symbols in the figures denote the same objects.

[0031] The in Figure 1The depicted system comprises a tank 10, in this case a stationary storage tank 10, which is filled with a liquefied gas product that is contained in the storage tank 10 in liquid form up to a liquid level 12 and in the gas phase above that level. A tank vehicle 14 has a product reservoir 16 in the form of a mobile tank 16, from which further liquefied gas product is to be filled into the tank 10 via a supply line 18. For this purpose, the tank 10 includes an upper filling opening 20 on its top and a lower filling opening 22 on its bottom.

[0032] A first filling line 24 connects the product reservoir 16 to the upper filling opening 20 via the supply line 18 and, for example, a manually operated shut-off valve 26. A second filling line 28 also connects the product reservoir 16 to the lower filling opening 22 via the supply line 18 and the shut-off valve 26. An upper filling valve 30 is arranged on the first filling line 24, and a lower filling valve 32 is arranged on the second filling line 28. The upper filling valve 30 has a first pneumatic control input 34, to which a first control line 36 is connected, and the lower filling valve 32 has a second pneumatic control input 38, to which a second control line 40 is connected.By controlling the upper filling valve 30 and the lower filling valve 32, the tank 10 can be filled with liquefied gas product from the product reservoir 16 via the upper filling opening 20 from the top and via the lower filling opening 22 from the bottom, by the upper and lower filling valves 30, 32 opening or closing different flow cross-sections of the first and second filling lines 24, 28 respectively.

[0033] The in Figure 1 the system shown or the one in Figure 1The device shown further comprises a control valve 42 with a first control output 44 connected to the first control line 36 and a second control output 46 connected to the second control line 40. The tank pressure in the tank 10 is applied as a control variable via a pressure measuring line 48 to a pressure input 50 of the control valve 42. As explained in more detail below, the control valve 42, based on the tank pressure received as a control variable, actuates the upper filling valve 30 or the lower filling valve 32, respectively, via the first control line 36 and the second control line 40, to fill the tank 10 such that the tank pressure corresponds to a predetermined setpoint or predetermined setpoint range.

[0034] The control pressure for the pneumatic actuation of the upper filling valve 30 and the lower filling valve 32 via the first and second control inputs 34, 38 is set in the Figure 1In the illustrated example, the pressure is provided by an external compressed gas supply 52, in particular a compressed air supply 52. ​​A regulator 58 is arranged in the control pressure line 56, which connects the compressed gas supply 52 to the compressed gas inlet 54 of the control valve 42. This regulator 58 regulates the control pressure to a predetermined value, for example, 6 bar. A pressure gauge 60 (pressure indicator PI) is also arranged on the pressure measuring line 48. A corresponding pressure gauge 62 (PI) is also arranged on the control pressure line 56. The tank pressure measured by the pressure gauge 60 and / or the control pressure measured by the pressure gauge 62 can be displayed to an operator via a display device of the device according to the invention.

[0035] A shut-off valve 64 is also arranged in the pressure measuring line 48, via which the connection to the tank 10 can be interrupted. A defined setting pressure can be applied to the control valve 42, in particular to the pressure inlet 50, via a test port 66 and a connection valve 68, in order to adjust the control valve 42, in particular to a desired setpoint or setpoint range.

[0036] In Figure 2The control valve 42 is shown in a sectional view. The control valve 42 comprises a housing 70, on the underside of which a connection housing 72, for example cylindrical, is arranged. The pressure inlet 50, to which the pressure measuring line 48 is connected, is located on the underside of the connection housing 72. The tank pressure applied via the pressure measuring line 48 acts on an elastic control bellows 74, which is compressed depending on the applied tank pressure. A control shaft 76 is arranged on the upper side of the control bellows 74, the upper section of which projects into the housing 70. Two cam-forming control disks 78, 80 are arranged axially spaced on the section of the control shaft 76 located in the housing 70.The control shaft 76 has an external thread at least in its upper section, and the control discs 78, 80 have a corresponding internal thread, so that they can be arranged on the control shaft 76 in different axial positions, similar to a spindle drive. During expansion or compression of the control bellows 74, the control shaft 76 is moved axially, and with it the control discs 78, 80. These can, for example, actuate pneumatic valves (not shown in detail) that transmit the control pressure applied at the compressed gas inlet 54 to actuate the first control inlet 34 of the upper filling valve 30 or the second control inlet 38 of the lower filling valve 32, in particular via the first control line 36 and the second control line 40.

[0037] In Figure 2It can also be seen that a spring assembly 82 is supported on the upper side of the control bellows 74 on the one hand and on the underside of the housing 70 on the other. This spring assembly is formed, in particular, by springs nested one inside the other in a cascade-like fashion, and exerts a counter-pressure on the elastic control bellows 74. The magnitude of the counter-pressure exerted by the spring assembly 82 can be adjusted by an adjusting element 84, for example, an adjusting screw 84. Both the elastic control bellows 74 and the spring assembly 82 can be made of a metallic material, for example, stainless steel. This also applies to the other components of the illustrated control valve.

[0038] In Figure 3 is shown a further embodiment of a system or device according to the invention, which is largely the embodiment from Figure 1 corresponds.

[0039] In contrast to the design according to Figure 1In the exemplary embodiment, the control pressure applied to the compressed gas inlet 54 is determined according to Figure 3 The pressure is supplied via the tank pressure. For this purpose, the tank pressure prevailing in the pressure measuring line 48 is applied to an intermediate tank 90 via an intermediate tank line 86 and a shut-off valve 88. The control pressure prevailing in the intermediate tank 90 is, in this case, transferred to the control pressure line 56 via a valve 92. Advantage of the in Figure 3 The embodiment shown is that the device according to the invention can operate autonomously, in particular autonomously from an external control pressure supply and a power supply. Reference sign

[0040] 10 Tank 12 Liquid level 14 Tanker 16 Product reservoir 18 Supply line 20 Upper filling opening 22 Lower filling opening 24 First filling line 26 Shut-off valve 28 Second filling line 30 Upper filling valve 32 Lower filling valve 34 First control input 36 First control line 38 Second control input 40 Second control line 42 Control valve 44 First control output 46 Second control output 48 Pressure measuring line 50 Pressure input 52 Compressed gas supply 54 Compressed gas input 56 Control pressure line 58 Regulator 60 Pressure gauge 62 Pressure gauge 64 Shut-off valve 66 Test port 68 Connection valve 70 Housing 72 Connection housing 74 Control bellows 76 Control shaft 78, 80 Control elements 82 Spring device 84 Adjusting element 86 Intermediate tank line 88 Shut-off valve 90 Intermediate tank 92 Valve

Claims

1. Device for filling a tank (10) with a product, in particular a liquefied gas product, comprising an upper filling valve (30) that can be arranged on a first filling line (24) connecting a product reservoir (16) with an upper filling opening (20) of the tank (10) and a lower filling valve (32) that can be arranged on a second filling line (28) connecting the product reservoir (16) with a lower filling opening (22) of the tank (10), characterized by the fact that The device comprises a control valve (42) to which the tank pressure in the tank (10) is applied as the control variable, and which is connected via a first control line (36) to the upper filling valve (30) and via a second control line (40) to the lower filling valve (32), wherein the control valve (42) actuates the upper filling valve (30) and the lower filling valve (32) to fill the tank (10) such that the tank pressure corresponds to a predetermined setpoint or setpoint range.

2. Device according to claim 1, characterized by the fact that the control valve (42) pneumatically actuates the upper filling valve (30) and the lower filling valve (32), preferably that the tank pressure in the tank (10) continues to be applied to an intermediate tank (90), and that a control pressure of the control valve (42) for pneumatically actuating the upper filling valve (30) and the lower filling valve (32) is supplied from the pressure in the intermediate tank (90).

3. Device according to one of the preceding claims, characterized by the fact that The tank pressure applied to the control valve (42) actuates a control shaft (76) of the control valve (42) in the axial direction, wherein two control elements (78, 80) are arranged on the control shaft (76) which, depending on the axial position of the control shaft (76), actuate the upper filling valve (30) and / or the lower filling valve (32) to fill the tank (10).

4. Device according to claim 3, characterized by the fact thatthe control elements on the control shaft (76) comprise control discs (78, 80) and / or that the control shaft (76) has an external thread, and that the control elements (78, 80) have an internal thread engaging with the external thread, so that the control elements (78, 80) can be arranged on the control shaft (76) in different axial positions and / or that the tank pressure actuates the control shaft (76) via a control bellows (74) which expands in the axial direction of the control shaft (76) depending on the tank pressure, wherein the control bellows (74) is preferably a metal bellows (74), preferably a stainless steel bellows (74).

5. Device according to claim 4, characterized by the fact that at least one section of the control shaft (76) having the control elements (78, 80) is arranged in a housing (70) of the control valve (42).

6. Device according to one of claims 4 or 5, characterized by the fact thatA spring device (82) is arranged between the control bellows (74) and a section of the control shaft (76) having the control elements (78, 80), exerting a counter-pressure on the control bellows (74).

7. Device according to claims 5 and 6, characterized by the fact that the spring assembly (82) is supported on the control bellows (74) on one side and on the housing (70) on the other.

8. Device according to one of claims 6 or 7, characterized by the fact that the spring assembly (82) comprises a plurality of nested springs.

9. Device according to one of claims 6 to 8, characterized by the fact that the steering shaft (76) extends through the spring assembly (82) to the steering bellows (74).

10. Device according to any one of claims 6 to 9, characterized by the fact that the spring assembly (82) is a metal spring assembly (82), preferably a stainless steel spring assembly (82).

11. Device according to any one of claims 6 to 10, characterized by the fact thatAn adjusting element (84) is arranged on a side of the spring assembly (82) facing away from the control bellows (74), with which a preload of the spring assembly (82) can be adjusted.

12. Device according to one of the preceding claims, characterized by the fact that The tank pressure is applied to the control valve (42) via a pressure measuring line (48), and a shut-off valve (64) is arranged in the pressure measuring line (48) with which the pressure measuring line (48) can be shut off, and a test connection (66) is provided between the shut-off valve (64) and the control valve (42) to which a setting pressure can be applied for adjusting the control valve (42).

13. System comprising a tank (10) to be filled with a product, in particular a liquefied gas product, and a product reservoir (16) and a device according to one of the preceding claims.

14. System according to claim 13, characterized by the fact thatthe tank (10) is a stationary storage tank (10), and the product reservoir (16) is a tank (16) mounted on a tank vehicle.

15. Method for filling a tank with a product, in particular a liquefied gas product, using a device according to one of claims 1 to 12 or a system according to one of claims 13 or 14.

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