Automatic acid adding system for electrolytic bath

Abstract

The utility model discloses an automatic acid adding system for an electrolytic bath, which relates to the technical field of electrolysis, aims to solve the problems of large workload and high risk of acid adding operation, and comprises a hydrogen fluoride storage tank, a hydrogen fluoride metering tank, the electrolytic bath, a first liquid level detection device and a second liquid level detection device, the hydrogen fluoride storage tank is used for storing hydrogen fluoride liquid, the hydrogen fluoride metering tank is communicated with the hydrogen fluoride storage tank through a first conveying pipeline, a first feeding valve connected with the control device is arranged on the first conveying pipeline, and the first liquid level detection device is arranged on the hydrogen fluoride metering tank and connected with the control device. The electrolytic tank is communicated with the hydrogen fluoride metering tank through a second conveying pipeline, a second feeding valve connected with the control device is arranged on the second conveying pipeline, the second liquid level detection device is arranged on the electrolytic tank and connected with the control device, manual control is not needed in the whole acid adding process, automation of the acid adding process can be achieved, the workload of acid adding operation is reduced, and the production efficiency is improved. And the risk of acid adding work is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electrolysis, and more specifically to an automatic acid adding system for an electrolytic cell. Background Art

[0002] The medium temperature fluorine electrolytic cell uses KHF 2 Anhydrous HF is added to make an electrolyte with the chemical formula of KF·(1.8~2.0)HF. From the chemical formula, the HF mass percentage content range (acidity range) of the electrolyte can be calculated to be 38.3~40.8%, and the generally controlled optimal value is 39.5%. When electrolysis occurs in the electrolytic cell, KF plays an ion migration role and is used as an electrolyte without being consumed. What is consumed is HF. Therefore, as the electrolysis continues, HF needs to be continuously replenished.

[0003] Domestic manufacturers basically add anhydrous hydrogen fluoride to the electrolytic cell intermittently, that is, after running for a period of time, the electrolytic power is calculated cumulatively, and then the amount of HF that needs to be added is calculated, and then the calculated amount of HF is added to the electrolytic cell. Because most electrolytic cells are continuously operated for 24 hours without stopping, the operators are generally divided into day shift, mid shift and night shift. The work of adding HF is to calculate the operating power of the electrolytic cell in the previous 8 hours after taking over, and then calculate the amount of HF that needs to be added, and add it by this shift. Due to different settings of the acid addition process system, the time for adding HF is generally 0.5 to 6 hours.

[0004] The existing acid addition method has the following problems: (1) During the time when acid is not added, the HF that undergoes electrolysis is dissolved in the electrolyte, which will inevitably cause the acidity of the electrolyte to decrease. The decrease in electrolyte acidity will inevitably cause the cathode voltage of the electrolytic cell to increase, consuming more electricity; (2) As HF is consumed, the electrolyte level will decrease. Once the pressure fluctuates, it is easier to damage the liquid seal of the electrolytic cell and cause an explosion; (3) When the HF addition speed is fast, it may cause the electrolyte acidity to be too high, affecting the service life of the electrolytic cell, especially the carbon anode, and increasing the maintenance rate of the electrolytic cell; (4) When the electrolyte acidity is too high, it will cause the HF content entrained in the fluorine gas and hydrogen to increase, which may not only cause environmental pollution, but also increase production costs; (5) The acid addition operation is a semi-automatic operation, and the operator has a large workload and high risks.

[0005] Therefore, how to solve the problem that the acid addition operation is heavy in workload and high in risk is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0006] In view of this, the purpose of the utility model is to provide an automatic acid adding system for an electrolytic cell, with automatic interlocking control, and no need for human intervention throughout the entire process, so as to reduce the workload of the acid adding operation and reduce the risk of the acid adding operation.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] An automatic acid adding system for an electrolytic cell, comprising:

[0009] Hydrogen fluoride storage tank, used to store hydrogen fluoride liquid;

[0010] A hydrogen fluoride metering tank is connected to the hydrogen fluoride storage tank through a first delivery pipeline, and a first feeding valve connected to the control device is provided on the first delivery pipeline;

[0011] A first liquid level detection device is provided in the hydrogen fluoride metering tank, and the first liquid level detection device is connected to the control device;

[0012] The electrolytic cell is connected to the hydrogen fluoride metering tank through a second delivery pipeline, and the second delivery pipeline is provided with a second feeding valve connected to the control device;

[0013] The second liquid level detection device is arranged in the electrolytic cell, and the second liquid level detection device is connected to the control device.

[0014] Preferably, the hydrogen fluoride metering tank is provided with a pressure detection device for detecting the pressure inside the hydrogen fluoride metering tank, and the pressure detection device is connected to the control device.

[0015] Preferably, the pressure detection device comprises:

[0016] A pressure gauge is installed in the hydrogen fluoride metering tank and is connected to the control device;

[0017] The pressure relief valve is arranged on the hydrogen fluoride metering tank and is communicated with the inner cavity of the hydrogen fluoride metering tank. The pressure relief valve is connected with the control device.

[0018] Preferably, the hydrogen fluoride metering tank is connected to a nitrogen delivery device, an output port of the nitrogen delivery device is provided with a regulating valve, and the regulating valve is connected to the control device.

[0019] Preferably, the second delivery pipeline is provided with a flow meter, and the flow meter is connected to the control device.

[0020] Preferably, the first liquid level detection device comprises a first radar liquid level meter for detecting the liquid level height of hydrogen fluoride in the hydrogen fluoride metering tank, and the first radar liquid level meter is connected to the control device.

[0021] Preferably, the second liquid level detection device includes a second radar level meter for detecting the liquid level height of hydrogen fluoride in the electrolytic cell, and also includes an acidity detector for detecting the acidity of hydrogen fluoride in the electrolytic cell. The second radar level meter and the acidity detector are both connected to the control device.

[0022] Preferably, at least two hydrogen fluoride storage tanks are provided, and the discharge ports of the at least two hydrogen fluoride storage tanks are connected to the first delivery pipeline through a third delivery pipeline, and a third feeding valve connected to the control device is provided on the third delivery pipeline.

[0023] Preferably, at least two hydrogen fluoride metering tanks are provided, and at least two hydrogen fluoride metering tanks are connected to the hydrogen fluoride storage tank.

[0024] Preferably, at least two electrolytic cells are provided, and at least two electrolytic cells are connected to the hydrogen fluoride metering tank.

[0025] The utility model provides an automatic acid-adding system for an electrolytic cell, comprising a hydrogen fluoride storage tank, a hydrogen fluoride metering tank, a first liquid level detection device, an electrolytic cell, a second liquid level detection device and a control device. Specifically, the hydrogen fluoride storage tank is used to store hydrogen fluoride liquid, the hydrogen fluoride metering tank is connected with the hydrogen fluoride storage tank through a first delivery pipeline, a first feeding valve connected with the control device is arranged on the first delivery pipeline, the opening and closing of the first feeding valve is controlled by the control device to realize the connection and disconnection between the hydrogen fluoride metering tank and the hydrogen fluoride storage tank, the first liquid level detection device is arranged on the hydrogen fluoride metering tank and connected with the control device, the first liquid level detection device is used to monitor the liquid level height of the hydrogen fluoride metering tank in real time, and send the monitored signal to the control device, and the opening and closing of the first feeding valve is controlled by the control device.

[0026] The electrolytic cell is connected to the hydrogen fluoride metering tank through a second delivery pipeline. A second feeding valve connected to a control device is provided on the second delivery pipeline. The opening and closing of the second feeding valve is controlled by the control device to realize the connection and disconnection between the hydrogen fluoride metering tank and the electrolytic cell. A second liquid level detection device is provided in the electrolytic cell and connected to the control device. The second liquid level detection device is used to monitor the liquid level height of the electrolytic cell in real time and send the monitored signal to the control device. The opening and closing of the second feeding valve is controlled by the control device. The entire acid addition process does not require manual control, and the automation of the acid addition process can be realized to reduce the workload of the acid addition operation and reduce the risk of the acid addition work. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 This is a schematic diagram of the structure of the automatic acid adding system for the electrolytic cell provided by the utility model;

[0029] Figure 2A schematic diagram of the structure of the hydrogen fluoride metering tank of the automatic acid addition system for the electrolytic cell provided by the utility model;

[0030] Figure 3 The utility model provides a schematic diagram of the structure of the electrolytic cell of the automatic acid addition system for the electrolytic cell.

[0031] Reference numerals:

[0032] 1- Hydrogen fluoride storage tank;

[0033] 2-Hydrogen fluoride metering tank;

[0034] 3- first liquid level detection device;

[0035] 4-Electrolyzer;

[0036] 5- second liquid level detection device;

[0037] 6-pressure detection device, 61-pressure gauge, 62-pressure relief valve;

[0038] 7- Regulating valve. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0040] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] The core of the utility model is to provide an automatic acid adding system for an electrolytic cell, with automatic interlocking control, and no need for manual intervention in the whole process, so as to reduce the workload of the acid adding operation and reduce the risk of the acid adding operation.

[0042] Please refer to Figure 1 , Figure 2 and Figure 3 An automatic acid adding system for an electrolytic cell comprises a hydrogen fluoride storage tank 1, a hydrogen fluoride metering tank 2, a first liquid level detection device 3, an electrolytic cell 4, a second liquid level detection device 5 and a control device.

[0043] Specifically, the hydrogen fluoride storage tank 1 is used to store hydrogen fluoride liquid, the hydrogen fluoride metering tank 2 is connected to the hydrogen fluoride storage tank 1 through a first delivery pipeline, and a first feeding valve connected to a control device is provided on the first delivery pipeline. The opening and closing of the first feeding valve is controlled by the control device to realize the connection and disconnection between the hydrogen fluoride metering tank 2 and the hydrogen fluoride storage tank 1. The first liquid level detection device 3 is provided in the hydrogen fluoride metering tank 2 and connected to the control device. The first liquid level detection device 3 is used to monitor the liquid level height of the hydrogen fluoride metering tank 2 in real time, and send the monitored signal to the control device, and the opening and closing of the first feeding valve are controlled by the control device.

[0044] The electrolytic cell 4 is connected to the hydrogen fluoride metering tank 2 through a second delivery pipeline. A second feeding valve connected to the control device is provided on the second delivery pipeline. The opening and closing of the second feeding valve is controlled by the control device to realize the connection and disconnection between the hydrogen fluoride metering tank 2 and the electrolytic cell 4. The second liquid level detection device 5 is provided in the electrolytic cell 4 and connected to the control device. The second liquid level detection device 5 is used to monitor the liquid level height of the electrolytic cell 4 in real time and send the monitored signal to the control device. The opening and closing of the second feeding valve is controlled by the control device. The entire acid addition process does not require manual control, and the automation of the acid addition process can be realized to reduce the workload of the acid addition operation and reduce the risk of the acid addition work.

[0045] The automatic acid adding system for the electrolytic cell arranged in the above manner can continuously add hydrogen fluoride to the electrolytic cell 4, so that the acidity of the electrolyte is basically stabilized near the optimal value, the cathode voltage of the electrolytic cell 4 is maintained stable, the consumption of electric energy is reduced, and the service life of the carbon anode is prevented from being shortened due to excessive acidity of the electrolyte, thereby reducing the production cost of the enterprise. The anhydrous HF is directly transported by pipeline without the need for subpackaging and transportation. Through the automatic interlocking control, no manual intervention is required throughout the process, so as to realize the automation of the acid adding process, reduce the workload of the acid adding operation, and reduce the risk of the acid adding operation.

[0046] In the above embodiment, the hydrogen fluoride metering tank 2 is provided with a pressure detection device 6 for detecting the pressure in the hydrogen fluoride metering tank 2 , and the pressure detection device 6 is connected to the control device.

[0047] It should be noted that the pressure in the hydrogen fluoride metering tank 2 is monitored in real time by the pressure detection device 6, and the monitored signal is sent to the control device, which further adjusts the pressure in the hydrogen fluoride metering tank 2 to avoid explosion of the hydrogen fluoride metering tank 2 due to excessive pressure.

[0048] In the above case, the pressure detection device 6 includes a pressure gauge 61 and a pressure relief valve 62. The pressure gauge 61 is arranged in the hydrogen fluoride metering tank 2 and is connected to the control device. The pressure relief valve 62 is arranged in the hydrogen fluoride metering tank 2 and is connected to the inner cavity of the hydrogen fluoride metering tank 2. The pressure relief valve 62 is connected to the control device.

[0049] It can be understood that the pressure in the hydrogen fluoride metering tank 2 is monitored in real time by the pressure gauge 61, and the monitored signal is sent to the control device. When the pressure in the hydrogen fluoride metering tank 2 is higher than the preset pressure value, the control device controls the pressure relief valve 62 to open, until the pressure in the hydrogen fluoride metering tank 2 reaches the preset pressure value, the control device controls the pressure relief valve 62 to close, so as to avoid the hydrogen fluoride metering tank 2 from exploding due to excessive pressure.

[0050] Furthermore, the hydrogen fluoride metering tank 2 is connected to a nitrogen delivery device, and the output port of the nitrogen delivery device is provided with a regulating valve 7 connected to the control device.

[0051] It should be noted that the pressure in the hydrogen fluoride metering tank 2 is monitored in real time by the pressure gauge 61, and the monitored signal is sent to the control device. When the pressure in the hydrogen fluoride metering tank 2 is lower than the preset pressure value, the control device controls the regulating valve 7 to open so that the nitrogen in the nitrogen delivery device is delivered to the hydrogen fluoride metering tank 2. After the pressure in the hydrogen fluoride metering tank 2 reaches the preset pressure value, the control device controls the regulating valve 7 to close to replenish the pressure of the hydrogen fluoride metering tank 2.

[0052] In the above embodiment, the second delivery pipeline is provided with a flow meter, and the flow meter is connected to the control device.

[0053] It is understandable that when the HF addition speed is fast, the electrolyte acidity may be too high, which affects the service life of the electrolytic cell 4, especially the carbon anode, and increases the maintenance rate of the electrolytic cell 4. By setting a flow meter, the speed of HF addition can be monitored in real time, and a signal is sent to the control device. When the speed exceeds the preset speed, the control device controls the opening of the second feeding valve to reduce the HF addition speed to the preset speed.

[0054] In this embodiment, a flow meter is provided to monitor the speed of adding HF, but in practical applications, there is no limitation to this as long as the above technical effects can be achieved.

[0055] On the basis of the above-mentioned embodiment, the first liquid level detection device 3 comprises a first radar liquid level meter for detecting the liquid level height of hydrogen fluoride in the hydrogen fluoride metering tank 2, and the first radar liquid level meter is connected to the control device.

[0056] It should be noted that a first radar level gauge is installed in the hydrogen fluoride metering tank 2. When the liquid level reaches the lower limit, a signal is sent to the control device to control the first feeding valve to open automatically, so that the hydrogen fluoride storage tank 1 can replenish the hydrogen fluoride metering tank 2. When the liquid level reaches the upper limit, a signal is sent to the control device to control the first feeding valve to automatically cut off and stop replenishing, thereby realizing automatic feeding of the hydrogen fluoride metering tank 2.

[0057] In the above embodiment, the second liquid level detection device 5 includes a second radar level gauge for detecting the liquid level height of hydrogen fluoride in the electrolytic cell 4, and also includes an acidity detector for detecting the acidity of hydrogen fluoride in the electrolytic cell 4. The second radar level gauge and the acidity detector are both connected to the control device.

[0058] It can be understood that a second radar level gauge and an acidity detector are installed in the electrolytic cell 4. When the second radar level gauge detects that the liquid level in the electrolytic cell 4 reaches the lower limit or the acidity detector detects that the acidity in the electrolytic cell 4 is lower than the set value, a signal is sent to the control device to control the second feeding valve to open automatically, and the hydrogen fluoride metering tank 2 is used to feed the electrolytic cell 4. When the liquid level reaches the upper limit or the acidity is higher than the set value, a signal is sent to the control device to control the second feeding valve to automatically cut off and stop feeding, thereby realizing automatic feeding of the electrolytic cell 4.

[0059] Among them, the first radar level gauge and the second radar level gauge can accurately measure the liquid levels in the hydrogen fluoride metering tank 2 and the electrolytic cell 4. When the acidity of the electrolyte is too high, the HF content entrained in the fluorine gas and hydrogen will increase, which may not only cause environmental pollution but also increase production costs. In this way, by setting up an acidity detector, the acidity of the electrolyte in the electrolytic cell 4 can be effectively monitored in real time, and the above situation can be avoided by controlling the second feeding valve.

[0060] As a preferred embodiment, at least two hydrogen fluoride storage tanks 1 are provided, and the discharge ports of at least two hydrogen fluoride storage tanks 1 are connected to the first delivery pipeline through a third delivery pipeline, and a third feeding valve connected to the control device is provided on the third delivery pipeline.

[0061] It should be noted that the hydrogen fluoride in the hydrogen fluoride storage tank 1 can be directly transported by pipeline without subpackaging and transportation. When the hydrogen fluoride in one of the hydrogen fluoride storage tanks 1 is used up, the control device controls the third feeding valve to open so that the other hydrogen fluoride storage tanks 1 can refill the hydrogen fluoride metering tank 2.

[0062] There are no restrictions on the number, specifications, and configuration of the hydrogen fluoride storage tank 1 as long as the above-mentioned technical effect can be achieved. Hydrogen fluoride is transported by an external tank truck, and the hydrogen fluoride in the tank truck is unloaded into the hydrogen fluoride storage tank 1 via the unloading platform.

[0063] In the above situation, at least two hydrogen fluoride metering tanks 2 are provided, and at least two hydrogen fluoride metering tanks 2 are connected to the hydrogen fluoride storage tank 1 .

[0064] It is understandable that there is no limitation on the number, specification, and arrangement of the hydrogen fluoride metering tank 2, as long as the above-mentioned technical effect can be achieved.

[0065] In the above embodiment, at least two electrolytic cells 4 are provided, and at least two electrolytic cells 4 are connected to the hydrogen fluoride metering tank 2 .

[0066] It should be noted that there is no limitation on the number, specification, and arrangement of the electrolytic cells 4, as long as the above-mentioned technical effects can be achieved.

[0067] In summary, the automatic acid adding system for electrolytic cells provided by the utility model, the hydrogen fluoride in the hydrogen fluoride storage tank 1 is transported to the hydrogen fluoride metering tank 2 at the electrolysis workshop site by a submerged pump through a pipeline, and the hydrogen fluoride metering tank 2 is designed with a first radar level gauge for real-time monitoring of the liquid level. When the liquid level reaches the lower limit, the first charging valve is controlled to open automatically, and the hydrogen fluoride storage tank 1 is used to add material to the hydrogen fluoride metering tank 2. When the liquid level reaches the upper limit, the first charging valve is controlled to be automatically cut off, and the material addition is stopped, thereby realizing automatic charging of the hydrogen fluoride metering tank 2, without the need for Manual operation, a hydrogen fluoride metering tank 2 supplies multiple electrolytic cells 4, when the second radar level gauge in the electrolytic cell 4 detects that the liquid level reaches the lower limit, the second feeding valve is controlled to open automatically, and the hydrogen fluoride metering tank 2 is used to feed the electrolytic cell 4, when the liquid level reaches the upper limit, the second feeding valve is controlled to be automatically cut off, and the feeding is stopped, so that the electrolytic cell 4 is automatically fed without manual operation. The entire acid addition process does not require manual operation, and the fully automated process of the acid addition operation can be realized to reduce the workload and operation risks of the operators.

[0068] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0069] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0070] The above is a detailed introduction to an automatic acid addition system for an electrolytic cell provided by the utility model. This article uses specific examples to illustrate the principle and implementation method of the utility model. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. An automatic acid adding system for an electrolytic cell, characterized in that: include: A hydrogen fluoride storage tank (1), used for storing hydrogen fluoride liquid; A hydrogen fluoride metering tank (2) is connected to the hydrogen fluoride storage tank (1) via a first delivery pipeline, wherein the first delivery pipeline is provided with a first feeding valve connected to the control device; A first liquid level detection device (3) is provided on the hydrogen fluoride metering tank (2), and the first liquid level detection device (3) is connected to the control device; The electrolytic cell (4) is connected to the hydrogen fluoride metering tank (2) via a second delivery pipeline, and the second delivery pipeline is provided with a second feeding valve connected to the control device; A second liquid level detection device (5) is provided in the electrolytic cell (4), and the second liquid level detection device (5) is connected to the control device.

2. The automatic acid adding system for electrolytic cell according to claim 1, characterized in that: The hydrogen fluoride metering tank (2) is provided with a pressure detection device (6) for detecting the pressure in the hydrogen fluoride metering tank (2), and the pressure detection device (6) is connected to the control device.

3. The automatic acid adding system for electrolytic cell according to claim 2, characterized in that: The pressure detection device (6) comprises: A pressure gauge (61) is disposed in the hydrogen fluoride metering tank (2), and the pressure gauge (61) is connected to the control device; A pressure relief valve (62) is provided on the hydrogen fluoride metering tank (2) and is in communication with the inner cavity of the hydrogen fluoride metering tank (2); the pressure relief valve (62) is connected to the control device.

4. The automatic acid adding system for electrolytic cell according to claim 3, characterized in that: The hydrogen fluoride metering tank (2) is connected to a nitrogen delivery device, the output port of the nitrogen delivery device is provided with a regulating valve (7), and the regulating valve (7) is connected to the control device.

5. The automatic acid adding system for electrolytic cell according to claim 4, characterized in that: The second delivery pipeline is provided with a flow meter, and the flow meter is connected to the control device.

6. The automatic acid adding system for electrolytic cell according to claim 5, characterized in that: The first liquid level detection device (3) comprises a first radar liquid level meter for detecting the height of the hydrogen fluoride liquid level in the hydrogen fluoride metering tank (2), and the first radar liquid level meter is connected to the control device.

7. The automatic acid adding system for electrolytic cell according to claim 6, characterized in that: The second liquid level detection device (5) comprises a second radar liquid level meter for detecting the liquid level height of hydrogen fluoride in the electrolytic cell (4), and also comprises an acidity detector for detecting the acidity of hydrogen fluoride in the electrolytic cell (4), and the second radar liquid level meter and the acidity detector are both connected to the control device.

8. The automatic acid adding system for electrolytic cell according to claim 1, characterized in that: At least two hydrogen fluoride storage tanks (1) are provided, and the discharge ports of at least two hydrogen fluoride storage tanks (1) are connected to the first delivery pipeline via a third delivery pipeline, and a third feeding valve connected to the control device is provided on the third delivery pipeline.

9. The automatic acid adding system for electrolytic cell according to claim 8, characterized in that: At least two hydrogen fluoride metering tanks (2) are provided, and at least two of the hydrogen fluoride metering tanks (2) are connected to the hydrogen fluoride storage tank (1).

10. The automatic acid adding system for electrolytic cell according to claim 9, characterized in that: At least two electrolytic cells (4) are provided, and at least two of the electrolytic cells (4) are connected to the hydrogen fluoride metering tank (2).

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