Fuel cell air supply system based on liquid fuel reforming and operation method

Abstract

The invention discloses a fuel cell air supply system based on liquid fuel reforming and an operation method. The system comprises an air filter, the output end of the air filter is connected with an air compressor through a gas pipeline, and the outlet end of the air compressor is connected with a cooler through a gas pipeline; the outlet end of the cooler is connected with a gas buffer tank, the output end of the gas buffer tank is connected with two types of output pipelines, the first type is a fuel cell gas supply pipeline and comprises a first fuel cell air path regulating valve, a second fuel cell air path regulating valve, a third fuel cell air path regulating valve and an Nth fuel cell air path regulating valve, and the Nth fuel cell air path regulating valve is a fuel cell gas supply pipeline. And the second type is a fuel processor gas supply path. According to the system, a single air compressor is matched with a plurality of high-temperature proton exchange membrane fuel cells and a fuel processor, so that the system process is simplified, parts are reduced, and the system reliability is improved; in the starting stage, the rotating speed of the air compressor is adjusted to be matched with the effective drift diameter of the fuel processor air path adjusting valve, surge of the air compressor is avoided, and the service life of the system is prolonged.

Description

Technical Field

[0001] This invention relates to the field of fuel cell power generation system technology, and more particularly to a fuel cell air supply system based on liquid fuel reforming and its operation method. Background Technology

[0002] Fuel cells based on liquid fuel reforming are a technology that uses fuels such as gasoline, diesel, methanol, and ethanol to produce hydrogen and then combines it with a high-temperature proton exchange membrane fuel cell. The advantages of this technology include a wide variety of fuels available, easy accessibility, low characteristic signals, and a simple thermal management system, making it suitable for applications in multiple scenarios.

[0003] The air supply system for fuel cells based on liquid fuel reforming primarily serves to supply air to the cathode of high-temperature proton exchange membrane (PEM) fuel cells and to provide the air required for the autothermal reforming hydrogen production process in the fuel processor. The air supply system directly impacts the performance, reliability, and safety of the liquid fuel reforming-based fuel cell system. Because high-temperature PEM fuel cell technology is relatively new, current commercially available single-fuel cell power ratings are relatively low. High-power systems require multiple fuel cells connected in parallel, and the air supply system must meet the air supply needs of multiple fuel cells. For high-temperature PEM fuel cells, insufficient metering will result in under-gas supply, reducing output power and potentially causing membrane electrode assembly (MEA) burnout. Excessive metering not only increases parasitic power consumption but can also lead to safety accidents due to excessive internal gas pressure. During the hydrogen production reaction in the fuel processor, precise control of the air-to-fuel ratio is crucial. The oxygen-to-carbon ratio directly affects the fuel processor's hydrogen production efficiency. Inaccurate air volume can lead to low hydrogen content in the reformed gas, resulting in under-gas supply to the anode and damage to the fuel cell. During load changes in fuel cell systems based on liquid fuel reforming, the air supply system needs to respond quickly to changes in load power to maintain a stable amount of reactant gas within the fuel cell. At the same time, due to the large power range, the air supply system needs to have a wide operating range to avoid surge under low flow conditions, which could affect the accuracy of air feeding and cause under-gas damage to the fuel cell system based on liquid fuel reforming during load changes.

[0004] Existing fuel cells typically use a single air supply system for each fuel cell. Fuel cell systems consisting of multiple fuel cells require multiple air supply systems, leading to system complexity, numerous components, and poor reliability. Current fuel cell air supply systems regulate compressor speed through pressure feedback, resulting in a lag in response. This affects the reactant ratio in the fuel processor, easily causing under-air damage to the fuel cell and increasing parasitic power consumption. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention discloses a fuel cell air supply system based on liquid fuel reforming, comprising: an air filter, the output end of which is connected to an air compressor via a gas pipeline; the outlet end of the air compressor is connected to a cooler via a gas pipeline; the outlet end of the cooler is connected to a gas buffer tank; and the output end of the gas buffer tank is connected to two types of output pipelines, the first type being a fuel cell air supply path, including a first fuel cell air path regulating valve, a second fuel cell air path regulating valve, a third fuel cell air path regulating valve, and an Nth fuel cell air path regulating valve. The output end of the first fuel cell air path regulating valve is connected to a first fuel cell air path flow meter; the second fuel cell air path regulating valve is connected to a second fuel cell air path flow meter; the third fuel cell air path regulating valve is connected to a third fuel cell air path flow meter; and the Nth fuel cell air path regulating valve is connected to an Nth fuel cell air path flow meter. The output end is connected to the first high-temperature proton exchange membrane fuel cell; the output end of the second fuel cell air path flow meter is connected to the second high-temperature proton exchange membrane fuel cell; the output end of the third fuel cell air path flow meter is connected to the third high-temperature proton exchange membrane fuel cell; the output end of the Nth fuel cell air path flow meter is connected to the Nth high-temperature proton exchange membrane fuel cell; the first high-temperature proton exchange membrane fuel cell is connected to the first back pressure regulating valve via a gas pipeline; the second high-temperature proton exchange membrane fuel cell is connected to the second back pressure regulating valve via a gas pipeline; the third high-temperature proton exchange membrane fuel cell is connected to the third back pressure regulating valve via a gas pipeline; the Nth high-temperature proton exchange membrane fuel cell is connected to the Nth back pressure regulating valve via a gas pipeline; wherein the second type is a fuel processor air supply path, including a fuel processor air path regulating valve, the output end of the fuel processor air path regulating valve is connected to the fuel processor air path flow meter, and the output end of the fuel processor air path flow meter is connected to the fuel processor.

[0006] A temperature sensor is installed on the pipeline between the cooler and the gas buffer tank, and a pressure sensor is installed on the output pipeline of the gas buffer tank.

[0007] The number of high-temperature proton exchange membrane fuel cells in the fuel cell gas supply path is determined based on the power level of the fuel cell system undergoing liquid fuel reforming, and can consist of 1 to n gas paths.

[0008] The air compressor's flow rate and pressure ratio meet the total gas volume requirements of the fuel cell system based on liquid fuel reforming.

[0009] The cooler is either air-cooled or water-cooled.

[0010] The first fuel cell air path regulating valve, the second fuel cell air path regulating valve, the third fuel cell air path regulating valve, the Nth fuel cell air path regulating valve, the fuel processor air path regulating valve, the first back pressure regulating valve, the second back pressure regulating valve, the third back pressure regulating valve, and the Nth back pressure regulating valve are electric ball valves or electric butterfly valves, enabling any degree of opening adjustment.

[0011] The first fuel cell air path flow meter, the second fuel cell air path flow meter, the third fuel cell air path flow meter, the Nth fuel cell air path flow meter, and the fuel processor air path flow meter are mass flow meters.

[0012] An operation method for a fuel cell air supply system based on liquid fuel reforming, comprising:

[0013] Fuel cell system startup phase: First, the fuel processor reforms and produces hydrogen. At this time, the air compressor is turned on, and compressed air enters the buffer tank to stabilize the flow. The fuel processor air path regulating valve is opened. Based on the monitoring value of the fuel processor air path flow meter, the speed of the air compressor is adjusted to ensure that the air supply flow meets the needs of the fuel processor. As the startup processing volume increases, the air supply volume increases to avoid the surge zone of the air compressor. At this time, the equivalent diameter of the fuel processor air path regulating valve can be increased. Based on the monitoring value of the fuel processor air path flow meter, the speed of the air compressor is adjusted to reduce parasitic power consumption.

[0014] During the low-power output stage of the system: The fuel processor requires precise air volume for hydrogen production through reforming. Based on real-time feedback from the air flow meter monitoring values ​​of the fuel processor, the speed of the air compressor is adjusted to ensure that the air supply flow meets the requirements of the fuel processor, generating qualified reformed gas that enters the first, second, third, and Nth high-temperature proton exchange membrane fuel cells. This opens the first, second, third, and Nth fuel cell air path regulating valves of multiple Class I fuel cell air supply paths. Based on real-time feedback from the air flow meters of these fuel cells, the first, second, third, and Nth back pressure regulating valves are adjusted to ensure that the air supply flow meets the operating requirements of the first, second, third, and Nth high-temperature proton exchange membrane fuel cells.

[0015] During the high-power output stage of the system: the air supply system is adjusted in the same way as during the low-power output stage. As the power level increases, the required air compressor flow rate and pressure ratio increase, causing the air compressor exhaust temperature to rise. At this time, the cooling system of the cooler is turned on to reduce the air compressor exhaust temperature. The temperature sensor monitors and provides feedback to ensure that the exhaust temperature is lower than the normal operating temperature of the first fuel cell air path flow meter, the second fuel cell air path flow meter, the third fuel cell air path flow meter, the Nth fuel cell air path flow meter, and the fuel processor air path flow meter. The pressure sensor monitors the outlet pressure of the buffer tank in real time. If the pressure exceeds the set value, the pressure is automatically released to improve system safety.

[0016] By employing the above technical solutions, this invention provides a fuel cell air supply system and operating method based on liquid fuel reforming. This system consists of a single air compressor matched with multiple high-temperature proton exchange membrane fuel cells and a fuel processor, simplifying the system flow, reducing components, and improving system reliability. During startup, adjusting the air compressor speed to match the effective flow diameter of the fuel processor's air path regulating valve avoids compressor surge and extends system lifespan. During system operation, the rapid response feedback from the fuel processor's air flow meter improves the accuracy of air supply, avoiding increased parasitic power consumption caused by excessive air supply and improving system efficiency. Automatic adjustment of exhaust temperature measurement accuracy through temperature monitoring and automatic pressure relief function through pressure monitoring enhance system safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a block diagram of the air supply system for a fuel cell based on liquid fuel reforming according to the present invention.

[0019] In the diagram: 1. Air filter; 2. Air compressor; 3. Cooler; 4. Temperature sensor; 5. Gas buffer tank; 6. Pressure sensor; 7. First fuel cell air path regulating valve; 8. Second fuel cell air path regulating valve; 9. Third fuel cell air path regulating valve; 10. Nth fuel cell air path regulating valve; 11. Fuel processor air path regulating valve; 12. First fuel cell air path flow meter; 13. Second fuel cell air path flow meter; 14. Third fuel cell air path flow meter; 15. Nth fuel cell air path flow meter; 16. Fuel processor air path flow meter; 17. First high-temperature proton exchange membrane fuel cell; 18. Second high-temperature proton exchange membrane fuel cell; 19. Third high-temperature proton exchange membrane fuel cell; 20. Nth high-temperature proton exchange membrane fuel cell; 21. Fuel processor; 22. First back pressure regulating valve; 23. Second back pressure regulating valve; 24. Third back pressure regulating valve; 25. Nth back pressure regulating valve. Detailed Implementation

[0020] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention:

[0021] like Figure 1The illustrated fuel cell air supply system based on liquid fuel reforming includes an air filter 1. The output of the air filter 1 is connected to an air compressor 2 via a gas pipeline. The outlet of the air compressor 2 is connected to a cooler 3 via a gas pipeline. The outlet of the cooler 3 is connected to a gas buffer tank 5. The output of the gas buffer tank 5 is connected to two types of output pipelines. The first type is a fuel cell air supply path, including a first fuel cell air path regulating valve 7, a second fuel cell air path regulating valve 8, a third fuel cell air path regulating valve 9, and an Nth fuel cell air path regulating valve 10. The output of the first fuel cell air path regulating valve 7 is connected to a first fuel cell air path flow meter 12. The second fuel cell air path regulating valve 8 is connected to a second fuel cell air path flow meter 13. The third fuel cell air path regulating valve 9 is connected to a third fuel cell air path flow meter 14. The Nth fuel cell air path regulating valve 10 is connected to an Nth fuel cell air path flow meter 15. The output of the first fuel cell air path flow meter 12 is connected to a first high-temperature proton exchange membrane. The first high-temperature proton exchange membrane fuel cell 17 is connected to the second high-temperature proton exchange membrane fuel cell 18, the output of the third high-temperature proton exchange membrane fuel cell 19 is connected to the third high-temperature proton exchange membrane fuel cell 14, and the output of the Nth high-temperature proton exchange membrane fuel cell 20 is connected to the Nth high-temperature proton exchange membrane fuel cell 15. The first high-temperature proton exchange membrane fuel cell 17 is connected to the first back pressure regulating valve 22 through a gas pipeline, the second high-temperature proton exchange membrane fuel cell 18 is connected to the second back pressure regulating valve 23 through a gas pipeline, the third high-temperature proton exchange membrane fuel cell 19 is connected to the third back pressure regulating valve 24 through a gas pipeline, and the Nth high-temperature proton exchange membrane fuel cell is connected to the Nth back pressure regulating valve 25 through a gas pipeline. The second type is a fuel processor air supply path, including a fuel processor air path regulating valve 11. The output of the fuel processor air path regulating valve 11 is connected to the fuel processor air path flow meter 16, and the output of the fuel processor air path flow meter 16 is connected to the fuel processor 21.

[0022] Furthermore, the number of gas supply paths for this type of fuel cell is determined by the power level of the fuel cell system based on liquid fuel reforming, and can consist of 1 to n gas paths.

[0023] Furthermore, the flow rate and pressure ratio of the air compressor 2 meet the total gas volume requirements of the fuel cell system based on liquid fuel reforming.

[0024] Furthermore, the cooler 3 can be air-cooled or water-cooled.

[0025] Furthermore, the buffer tank 5 has an electric pressure relief function.

[0026] Furthermore, the first fuel cell air path regulating valve 7, the second fuel cell air path regulating valve 8, the third fuel cell air path regulating valve 9, the Nth fuel cell air path regulating valve 10, the fuel processor air path regulating valve 11, the first back pressure regulating valve 22, the second back pressure regulating valve 23, the third back pressure regulating valve 24, and the Nth back pressure regulating valve 25 are electric ball valves or electric butterfly valves, enabling any degree of opening adjustment.

[0027] Furthermore, the first fuel cell air path flow meter 12, the second fuel cell air path flow meter 13, the third fuel cell air path flow meter 14, the Nth fuel cell air path flow meter 15, and the fuel processor air path flow meter 16 are mass flow meters.

[0028] An operating method for the above-mentioned fuel cell air supply system based on liquid fuel reforming is as follows:

[0029] During the startup phase of a fuel cell system based on liquid fuel reforming, the fuel processor 21 first operates to reform and produce hydrogen. At this time, the air compressor 2 is turned on, and compressed air enters the buffer tank 5 to stabilize the flow. The fuel processor air path regulating valve 11 is opened. Based on the real-time feedback from the fuel processor air path flow meter 16, the speed of the air compressor 2 is adjusted to ensure the air supply flow meets the requirements of the fuel processor 21. If the air demand is relatively small during startup, to avoid surge under low flow conditions that could affect air feed accuracy, the equivalent diameter of the fuel processor air path regulating valve 11 is reduced, and the speed of the air compressor 2 is increased to avoid the surge zone. As the startup throughput increases, the air supply increases. To avoid the air compressor's surge zone, the equivalent diameter of the fuel processor air path regulating valve 11 can be increased. Based on the real-time feedback from the fuel processor air path flow meter 16, the speed of the air compressor 2 is adjusted to reduce parasitic power consumption.

[0030] During the low-power output phase of the system, the fuel processor 21 requires a precise air volume for hydrogen production through reforming. Based on real-time feedback from the air flow meter 16 in the fuel processor's air path, the speed of the air compressor 2 is adjusted to ensure that the air supply flow meets the requirements of the fuel processor 21, generating qualified reformed gas that enters the first high-temperature proton exchange membrane fuel cell 17, the second high-temperature proton exchange membrane fuel cell 18, the third high-temperature proton exchange membrane fuel cell 19, and the Nth high-temperature proton exchange membrane fuel cell 20. This opens the first fuel cell air path regulating valve 7, the second fuel cell air path regulating valve 8, and the third fuel cell air path regulating valve 8, which are part of the multiple Class I fuel cell air supply paths. The air supply regulating valve 9 and the Nth fuel cell air supply regulating valve 10 adjust the first back pressure regulating valve 22, the second back pressure regulating valve 23, the third back pressure regulating valve 24 and the Nth back pressure regulating valve 25 in real time according to the monitoring values ​​of the first fuel cell air supply flow meter 12, the second fuel cell air supply flow meter 13, the third fuel cell air supply flow meter 14 and the Nth fuel cell air supply flow meter 15 so that the air supply flow meets the usage requirements of the first high temperature proton exchange membrane fuel cell 17, the second high temperature proton exchange membrane fuel cell 18, the third high temperature proton exchange membrane fuel cell 19 and the Nth high temperature proton exchange membrane fuel cell 20.

[0031] During the high-power output phase of the system, the air supply system is adjusted in the same way as during the low-power output phase. As the power level increases, the required flow rate and pressure ratio of air compressor 2 increase, causing the exhaust temperature of air compressor 2 to rise. At this time, the cooling system of cooler 3 is activated to reduce the exhaust temperature of air compressor 2. The temperature sensor 4 monitors and provides feedback to ensure that the exhaust temperature is lower than the normal operating temperatures of the first fuel cell air path flow meter 12, the second fuel cell air path flow meter 13, the third fuel cell air path flow meter 14, the Nth fuel cell air path flow meter 15, and the fuel processor air path flow meter, thus ensuring test accuracy. Pressure sensor 6 continuously monitors the outlet pressure of buffer tank 5. If the pressure exceeds the set value, it automatically releases pressure to improve system safety.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A fuel cell air supply system based on liquid fuel reforming, characterized in that... include: An air filter (1) is connected to an air compressor (2) via a gas pipeline at its output end. The air compressor (2) is connected to a cooler (3) via a gas pipeline at its outlet end. The cooler (3) is connected to a gas buffer tank (5) at its outlet end. The gas buffer tank (5) is connected to two types of output pipelines, the first being a fuel cell air supply pipeline, including a first fuel cell air path regulating valve (7), a second fuel cell air path regulating valve (8), a third fuel cell air path regulating valve (9), and an Nth fuel cell air path regulating valve (10). The output of the first fuel cell air path regulating valve (7) is connected to the first fuel cell air path flow meter (12), the second fuel cell air path regulating valve (8) is connected to the second fuel cell air path flow meter (13), the third fuel cell air path regulating valve (9) is connected to the third fuel cell air path flow meter (14), and the Nth fuel cell air path regulating valve (10) is connected to the Nth fuel cell air path flow meter (15); the output of the first fuel cell air path flow meter (12) is connected to the first high-temperature proton exchange membrane fuel cell (17). The output of the second fuel cell air path flow meter (13) is connected to the second high-temperature proton exchange membrane fuel cell (18), the output of the third fuel cell air path flow meter (14) is connected to the third high-temperature proton exchange membrane fuel cell (19), and the output of the Nth fuel cell air path flow meter (15) is connected to the Nth high-temperature proton exchange membrane fuel cell (20). The first high-temperature proton exchange membrane fuel cell (17) is connected to the first back pressure regulating valve (22) through a gas pipeline, and the second high-temperature proton exchange membrane fuel cell (18) is connected to the first back pressure regulating valve (22) through a gas pipeline. The third high-temperature proton exchange membrane fuel cell (19) is connected to the second back pressure regulating valve (24) via a gas pipeline, and the Nth high-temperature proton exchange membrane fuel cell is connected to the Nth back pressure regulating valve (25) via a gas pipeline; wherein the second type is a fuel processor air supply path, including a fuel processor air path regulating valve (11), the output end of the fuel processor air path regulating valve (11) is connected to the fuel processor air path flow meter (16), and the output end of the fuel processor air path flow meter (16) is connected to the fuel processor (21).

2. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: A temperature sensor (4) is installed on the pipeline between the cooler (3) and the gas buffer tank (5), and a pressure sensor (6) is installed on the output pipeline of the gas buffer tank (5).

3. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: The number of high-temperature proton exchange membrane fuel cells in the fuel cell gas supply path is determined based on the power level of the fuel cell system undergoing liquid fuel reforming, and can consist of 1 to n gas paths.

4. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: The air compressor (2) has a flow rate and pressure ratio that meet the total gas volume requirements of the fuel cell system based on liquid fuel reforming.

5. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: The cooler (3) is either air-cooled or water-cooled.

6. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: The first fuel cell air path regulating valve (7), the second fuel cell air path regulating valve (8), the third fuel cell air path regulating valve (9), the Nth fuel cell air path regulating valve (10), the fuel processor air path regulating valve (11), the first back pressure regulating valve (22), the second back pressure regulating valve (23), the third back pressure regulating valve (24), and the Nth back pressure regulating valve (25) are electric ball valves or electric butterfly valves, enabling any degree of opening adjustment.

7. The fuel cell air supply system based on liquid fuel reforming according to claim 1, characterized in that: The first fuel cell air path flow meter (12), the second fuel cell air path flow meter (13), the third fuel cell air path flow meter (14), the Nth fuel cell air path flow meter (15), and the fuel processor air path flow meter (16) are mass flow meters.

8. A method for operating a fuel cell air supply system based on liquid fuel reforming as described in any one of claims 1 to 7, characterized in that: Fuel cell system startup phase: First, run the fuel processor (21) to reform and produce hydrogen. At this time, turn on the air compressor (2) and the compressed air enters the buffer tank (5) to stabilize the flow. Open the fuel processor air path regulating valve (11). According to the monitoring value of the fuel processor air path flow meter (16), adjust the speed of the air compressor (2) so that the air supply flow meets the needs of the fuel processor (21). As the startup processing volume increases, the air supply volume increases to avoid the surge zone of the air compressor. At this time, the equivalent diameter of the fuel processor air path regulating valve (11) can be increased. According to the monitoring value of the fuel processor air path flow meter (16), adjust the speed of the air compressor (2) to reduce parasitic power consumption. During the low-power output stage of the system: The fuel processor (21) requires a precise air volume for hydrogen production through reforming. Based on the real-time feedback from the air flow meter (16) of the fuel processor, the speed of the air compressor (2) is adjusted to ensure that the air supply flow meets the requirements of the fuel processor (21), generating qualified reformed gas that enters the first high-temperature proton exchange membrane fuel cell (17), the second high-temperature proton exchange membrane fuel cell (18), the third high-temperature proton exchange membrane fuel cell (19), and the Nth high-temperature proton exchange membrane fuel cell (20). This opens the first fuel cell air path regulating valve (7), the second fuel cell air path regulating valve (8), and the third fuel cell air path regulating valve (8) of the multiple Class I fuel cell air supply paths. Valve (9) and Nth fuel cell air path regulating valve (10) adjust the first back pressure regulating valve (22), second back pressure regulating valve (23), third back pressure regulating valve (24) and Nth back pressure regulating valve (25) in real time according to the monitoring values ​​of the first fuel cell air path flow meter (12), second fuel cell air path flow meter (13), third fuel cell air path flow meter (14) and Nth fuel cell air path flow meter (15) so that the air supply flow meets the usage requirements of the first high temperature proton exchange membrane fuel cell (17), second high temperature proton exchange membrane fuel cell (18), third high temperature proton exchange membrane fuel cell (19) and Nth high temperature proton exchange membrane fuel cell (20); High power output stage of the system: The adjustment method of the air supply system is the same as that of the low power output stage. As the power level increases, the required air compressor (2) flow rate and pressure ratio increase, which causes the air compressor (2) exhaust temperature to rise. At this time, the cooling system of the cooler (3) is turned on to reduce the air compressor (2) exhaust temperature. The temperature sensor (4) monitors and provides feedback to make the exhaust temperature lower than the normal operating temperature of the first fuel cell air path flow meter (12), the second fuel cell air path flow meter (13), the third fuel cell air path flow meter (14), the Nth fuel cell air path flow meter (15), and the fuel processor air path flow meter (16). The pressure sensor (6) monitors the outlet pressure of the buffer tank (5) at all times. If the pressure exceeds the set value, it automatically depressurizes to improve system safety.

Images