High-precision differential pressure measuring device and method for measuring differential pressure

Abstract

The present invention discloses a high-precision differential pressure measuring device, including a differential pressure transmitter, wherein two sides of the differential pressure transmitter are respectively connected to a reference sampling detection component and a sampling detection component to be tested; the reference sampling detection component includes an air storage bin, which is used to store reference space environment air to form a reference pressure value; the sampling detection component to be tested includes an external air circuit, which is connected to the external space environment air to detect the external environment pressure value; the data displayed by the differential pressure transmitter is the pressure difference value between the air storage bin and the external space environment. The present invention also discloses a method for measuring the pressure difference using the high-precision differential pressure measuring device. The present invention has an ingenious structural design, is easy to use, and has wide applicability. The air in the air storage bin can provide a reference pressure, providing a basis for measuring the pressure difference between the two environments, thereby increasing the measurement accuracy of the pressure difference, and can also be used as a pressure standard to accurately monitor changes in the surrounding environment.

Description

Technical Field

[0001] The present invention relates to the field of environmental differential pressure measurement, and in particular to a high-precision differential pressure measurement device, and a method for measuring differential pressure based on the high-precision differential pressure measurement device. Background Art

[0002] Forming positive pressure in clean space and negative pressure in contaminated space can help effectively ensure the safety of clean space and avoid the spread of pollution. Such measures are often used in engineering facilities such as clean areas of civil air defense projects and isolation areas of hospitals. The positive pressure value formed in civil air defense projects is generally 50Pa~150 Pa, while the positive pressure value formed in the three-defense area of ​​ships is about 500 Pa, and the negative pressure value in the isolation area of ​​hospitals is generally not less than 5~10 Pa. In addition, studies have shown that when the positive pressure of the environment reaches 1000 Pa in a short period of time, the human body begins to feel uncomfortable. Therefore, the range of the equipment required to measure the positive and negative pressures formed in conventional human living environments is 5~1000 Pa. In order to ensure the effectiveness of positive or negative pressure measures, it is necessary to use a differential pressure measuring device to monitor the pressure difference between a specific space environment and the external environment in real time.

[0003] At present, there are two main methods for measuring the pressure difference between the internal and external space environments: the first is the indirect method, which uses a set of measuring equipment to measure the absolute pressure of the internal and external space environments one after another, or uses two sets of measuring equipment to measure the absolute pressure of the internal and external space environments at the same time, and takes the pressure difference as the pressure difference between the internal and external space environments. This method is more common, but the measurement accuracy is very limited. Because the range of the equipment required to measure the absolute pressure is usually greater than the standard atmospheric pressure (Po = 101325Pa), using this equipment to measure the pressure difference of 5~1000 Pa will cause a large system error. In addition, when using two sets of measuring equipment for measurement, there is also an error between the two sets of equipment. Therefore, the accuracy of the environmental pressure difference measured by the indirect method is not high.

[0004] The second is the direct method, which is to set up a pressure differential measuring tube that runs through the internal and external space environments in advance, and use a set of measuring equipment to connect the internal and external space environments at the same time to directly measure the pressure difference between the internal and external space environments. This method has high measurement accuracy, but it requires a preset pressure differential measuring tube that connects the two spaces in advance. For environments without preset pressure differential measuring tubes, the direct method cannot be used for measurement.

[0005] Therefore, it is necessary to design a pressure difference measuring device with high measurement accuracy and easy use. Summary of the invention

[0006] The present invention provides a high-precision pressure difference measuring device and a method for measuring pressure difference, which are easy to use and have high measurement accuracy. The specific technical scheme is as follows:

[0007] A high-precision differential pressure measuring device, which includes a differential pressure transmitter, and the two sides of the differential pressure transmitter are respectively connected to a reference sampling detection component and a sampling detection component to be tested; the reference sampling detection component includes an air storage bin, which is used to store reference space environment air to form a reference pressure value; the sampling detection component to be tested includes an external air circuit, which is connected to the external space environment air to detect the external environment pressure value; the data displayed by the differential pressure transmitter is the pressure difference value between the air storage bin and the external space environment.

[0008] Furthermore, an air storage bin air inlet pipe and an inner bin air path are respectively provided at both ends of the air storage bin; air can enter the air storage bin through the air storage bin air inlet pipe, and an air storage bin air inlet pipe valve is provided on the air storage bin air inlet pipe, and the air storage bin air inlet pipe valve is used to control the opening and closing of the air storage bin air inlet pipe; the inner bin air path is connected to the differential pressure transmitter.

[0009] Furthermore, the inner warehouse gas circuit includes an inner warehouse gas circuit main pipe, an inner warehouse absolute pressure measuring branch pipe and an inner warehouse pressure differential measuring branch pipe. One end of the inner warehouse gas circuit main pipe is connected to the gas storage bin, and the other end of the inner warehouse gas circuit main pipe is connected to the inner warehouse absolute pressure measuring branch pipe and the inner warehouse pressure differential measuring branch pipe; one end of the inner warehouse pressure differential measuring branch pipe away from the inner warehouse gas circuit main pipe is connected to the differential pressure transmitter; one end of the inner warehouse absolute pressure measuring branch pipe away from the inner warehouse gas circuit main pipe is connected to the inner warehouse pressure transmitter, and the inner warehouse pressure transmitter can measure the air pressure in the gas storage bin.

[0010] Furthermore, the external gas circuit includes an external gas circuit main pipe, an external absolute pressure measuring branch pipe and an external differential pressure measuring branch pipe. One end of the external gas circuit main pipe is connected to the external environment, and the other end of the external gas circuit main pipe is connected to the external absolute pressure measuring branch pipe and the external differential pressure measuring branch pipe; the end of the external differential pressure measuring branch pipe away from the external gas circuit main pipe is connected to the differential pressure transmitter; the end of the external absolute pressure measuring branch pipe away from the external gas circuit main pipe is connected to the external warehouse pressure transmitter, and the external warehouse pressure transmitter can measure the air pressure of the external environment.

[0011] Furthermore, the pipe diameters of the inner warehouse gas circuit main pipe and the outer warehouse gas circuit main pipe are larger than the pipe diameters of the inner warehouse absolute pressure measurement branch pipe, the inner warehouse pressure difference measurement branch pipe, the external absolute pressure measurement branch pipe and the external pressure difference measurement branch pipe, so as to facilitate the rapid balancing of the air pressure in each part.

[0012] Furthermore, the inner warehouse gas main pipe and the external gas main pipe use DN5-20 pipelines, preferably DN10 pipelines; the inner warehouse absolute pressure measurement branch, the inner warehouse pressure difference measurement branch, the external absolute pressure measurement branch and the external pressure difference measurement branch use DN4-16 pipelines, preferably DN8 pipelines.

[0013] Furthermore, the measuring range of the internal pressure transmitter and the external pressure transmitter is ±500kPa~2000kPa, with an accuracy of 2%~5%; the measuring range of the differential pressure transmitter is ±0.5kPa~2.0 kPa, with an accuracy of 0.5%~2%.

[0014] Furthermore, the range of the internal pressure transmitter and the external pressure transmitter is ±1000 kPa, and the accuracy is 2%; the range of the differential pressure transmitter is ±1.0 kPa, and the accuracy is 1%.

[0015] Furthermore, valves are provided on the inner warehouse gas main pipe, the inner warehouse absolute pressure measurement branch pipe, the inner warehouse pressure differential measurement branch pipe, the external gas main pipe, the external absolute pressure measurement branch pipe and the external pressure differential measurement branch pipe. By opening and closing each valve, the air tightness of each part of the device can be checked one by one.

[0016] A method for measuring differential pressure based on the above-mentioned high-precision differential pressure measuring device comprises the following steps:

[0017] The first step is to start the device and conduct self-inspection to ensure that the pipelines and equipment are clean and unobstructed, and the pipelines and valves are connected intact and leak-free;

[0018] The second step is to open the air inlet pipe valve of the air storage tank in a space environment and balance for about 1 minute until the absolute pressure value inside the air storage tank displayed by the internal tank pressure transmitter and the absolute pressure value of the external environment displayed by the external pressure transmitter are stable. At this time, the pressure difference ΔP measured by the differential pressure transmitter is 0, and then close the air inlet pipe valve of the air storage tank and the differential pressure transmitter;

[0019] The third step is to move the device to another space environment to balance for about 1 minute, and continuously collect data for 1 minute to measure and calculate the gas storage tank leakage rate R.

[0020] R=|P i -P0| / t

[0021] Where P i is the end point pressure, P0 is the initial pressure, and t is the interval time; if the leakage rate R in the gas storage bin>1 Pa / min, it is considered that the leakage rate R does not meet the measurement requirements; if the leakage rate R in the gas storage bin≤1 Pa / min, it is considered that the leakage rate R meets the measurement requirements;

[0022] If the leakage rate R does not meet the measurement requirements, it is considered that the airtightness of the gas storage bin is not good, and it is necessary to check and adjust the gas storage bin and the pipes and valves connected to it, and start again from the first step; if the leakage rate R meets the measurement requirements, it is considered that the airtightness of the gas storage bin is good, and the pressure value P1 measured by the internal bin pressure transmitter is valid, and the next step can be performed;

[0023] The fourth step is to read the current external environment pressure P2 measured by the external pressure transmitter, and preliminarily determine the pressure difference dP between the gas storage tank and the external environment as:

[0024] dP=|P2-P1|

[0025] If dP>1000 Pa, it is considered that the current pressure difference exceeds the measurement range of this device, and a measuring device with a larger measurement range needs to be replaced; if dP<1000 Pa, it is considered that the current pressure difference is within the measurement range of this device, and the next step can be performed;

[0026] Step 5. Turn on the differential pressure transmitter. When the absolute pressure value of the external environment displayed by the external pressure transmitter is stable, the data displayed by the differential pressure transmitter is the high-precision differential pressure value.

[0027] The present invention has an ingenious structural design, is easy to use, has a low production cost, and has high measurement accuracy. The air in the air storage bin can provide a reference pressure, providing a basis for measuring the pressure difference between the two environments, thereby increasing the measurement accuracy of the pressure difference, and can also be used as a pressure standard to accurately monitor changes in the surrounding environment. In addition, the present invention combines the technical advantages of the indirect method and the direct method for measuring the pressure difference, and can obtain high-precision measurement results even in situations where there is no reserved pressure difference measurement tube, and is suitable for various space environments.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0030] Figure 1 is a schematic diagram of a high-precision pressure difference measuring device of the present invention;

[0031] Figure 2 This is a flow chart of the high-precision differential pressure measuring device of the present invention when in use. DETAILED DESCRIPTION

[0032] In order to better understand the purpose, function and specific design scheme of the present invention, the high-precision pressure difference measuring device and the method for measuring pressure difference of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0033] like Figure 1As shown, the high-precision differential pressure measuring device of the present invention includes a differential pressure transmitter 4, the low-pressure side of the differential pressure transmitter 4 is connected to a reference sampling detection component, the reference sampling detection component includes an air storage bin 1, and the air storage bin 1 is used to store reference space environment air to form a reference pressure value; the high-pressure side of the differential pressure transmitter 4 is connected to a sampling detection component to be tested, the sampling detection component to be tested includes an external air circuit, and the external air circuit is connected to the external space environment air to detect the external environment pressure value; the data displayed by the differential pressure transmitter 4 is the pressure difference value between the air storage bin and the external space environment.

[0034] Specifically, an air storage bin air inlet pipe 17 is provided at one end of the air storage bin 1, and air can enter the air storage bin 1 through the air storage bin air inlet pipe 17. An air storage bin air inlet pipe valve 18 is provided on the air storage bin air inlet pipe 17, and the air storage bin air inlet pipe valve 18 is used to control the opening and closing of the air storage bin air inlet pipe 17. An inner bin air path is provided at the other end of the air storage bin 1, and the inner bin air path is connected to the differential pressure transmitter 4.

[0035] The inner chamber gas circuit of this embodiment includes an inner chamber gas circuit main pipe 5, an inner chamber absolute pressure measurement branch pipe 6 and an inner chamber pressure difference measurement branch pipe 7. One end of the inner chamber gas circuit main pipe 5 is connected to the gas storage bin 1, and the other end of the inner chamber gas circuit main pipe 5 is connected to the inner chamber absolute pressure measurement branch pipe 6 and the inner chamber pressure difference measurement branch pipe 7. The end of the inner chamber pressure difference measurement branch pipe 7 away from the inner chamber gas circuit main pipe 5 is connected to the differential pressure transmitter 4; the end of the inner chamber absolute pressure measurement branch pipe 6 away from the inner chamber gas circuit main pipe 5 is connected to the inner chamber pressure transmitter 2, and the inner chamber pressure transmitter 2 can measure the air pressure P1 in the gas storage bin 1. Preferably, the volume of the gas storage bin is 80~250 cm 3 , while facilitating the transportation of the equipment, it can also accurately provide reference pressure.

[0036] The external gas circuit includes an external gas circuit main pipe 8, an external absolute pressure measuring branch pipe 9 and an external differential pressure measuring branch pipe 10. One end of the external gas circuit main pipe 8 is connected to the external environment, and the other end of the external gas circuit main pipe 8 is connected to the external absolute pressure measuring branch pipe 9 and the external differential pressure measuring branch pipe 10. The end of the external differential pressure measuring branch pipe 10 away from the external gas circuit main pipe 8 is connected to the differential pressure transmitter 4; the end of the external absolute pressure measuring branch pipe 9 away from the external gas circuit main pipe 8 is connected to the external warehouse pressure transmitter 3, and the external warehouse pressure transmitter 3 can measure the air pressure P2 of the external environment.

[0037] It is worth noting that, in order to facilitate the rapid balance of the air pressure in each part, the pipe diameters of the inner chamber gas circuit main pipe 5 and the external gas circuit main pipe 8 are slightly larger than the pipe diameters of the inner chamber absolute pressure measurement branch pipe 6, the inner chamber pressure difference measurement branch pipe 7, the external absolute pressure measurement branch pipe 9, and the external pressure difference measurement branch pipe 10. In this embodiment, the inner chamber gas circuit main pipe 5 and the external gas circuit main pipe 8 use DN5-20 pipes, preferably DN10 pipes; the inner chamber absolute pressure measurement branch pipe 6, the inner chamber pressure difference measurement branch pipe 7, the external absolute pressure measurement branch pipe 9, and the external pressure difference measurement branch pipe 10 use DN4-16 pipes, preferably DN8 pipes.

[0038] Preferably, in order to reduce the manufacturing cost of the present invention, the internal pressure transmitter 2 and the external pressure transmitter 3 are sensors with a large range and low precision. The range of the internal pressure transmitter 2 and the external pressure transmitter 3 of this embodiment is ±500kPa~2000kPa, and the precision is 2%~5%. It is preferred to use the internal pressure transmitter 2 and the external pressure transmitter 3 with a range of ±1000 kPa and a precision of 2%; the differential pressure transmitter 4 is a sensor with a small range and high precision. The range of the differential pressure transmitter 4 of this embodiment is ±0.5kPa~2.0 kPa, and the precision is 0.5%~2%. It is preferred to use a differential pressure transmitter 4 with a range of ±1.0 kPa and a precision of 1%.

[0039] Preferably, in order to facilitate the detection of air leakage problems in the equipment, the inner warehouse gas circuit main pipe 5 of this embodiment is provided with an inner warehouse gas circuit main pipe valve 11, the inner warehouse absolute pressure measurement branch pipe 6 is provided with an inner warehouse absolute pressure measurement branch pipe valve 12, the inner warehouse differential pressure measurement branch pipe 7 is provided with an inner warehouse differential pressure measurement branch pipe valve 13, the external gas circuit main pipe 8 is provided with an external gas circuit main pipe valve 14, the external absolute pressure measurement branch pipe 9 is provided with an external absolute pressure measurement branch pipe valve 15, and the external differential pressure measurement branch pipe 10 is provided with an external differential pressure measurement branch pipe valve 16. By opening and closing each valve, the air tightness of each part of the device can be checked one by one.

[0040] like Figure 2 As shown, Figure 2 The present invention is a schematic diagram of the use process of the present invention. When the present invention measures the pressure difference between two space environments, the method is as follows:

[0041] The first step is to start the equipment and perform self-inspection, open the valves on the pipeline, and ensure that the pipeline and equipment are clean and unobstructed, and that the pipeline and valve connections are intact and there are no leaks.

[0042] The second step is to open the air inlet pipe valve 18 of the air storage bin in a space environment and balance for about 1 minute until the absolute pressure value P1 inside the air storage bin 1 displayed by the internal bin pressure transmitter 2 and the absolute pressure value of the external environment displayed by the external pressure transmitter 3 are stable. At this time, the pressure difference ΔP measured by the differential pressure transmitter 4 is displayed as 0, and then close the air inlet pipe valve 18 of the air storage bin and the differential pressure transmitter 4.

[0043] The third step is to move the present invention to another space environment for equilibration for about 1.0 minute, and continuously collect data for 1 minute to measure and calculate the gas leakage rate R of the gas storage bin 1.

[0044] R=|P i -P0| / t

[0045] Where P i is the end pressure, P0 is the initial pressure, and t is the interval time. If the leakage rate R in the gas storage bin is greater than 1 Pa / min, it is considered that the leakage rate R does not meet the measurement requirements. If the leakage rate R in the gas storage bin is less than 1 Pa / min, it is considered that the leakage rate R meets the measurement requirements.

[0046] If the leakage rate R does not meet the measurement requirements, it is considered that the airtightness of the gas storage bin 1 is not good, and it is necessary to check and adjust the gas storage bin and the pipes and valves connected to it, and start again from the first step; if the leakage rate R meets the measurement requirements, it is considered that the airtightness of the gas storage bin 1 is good, and P1 measured by the internal bin pressure transmitter 2 is valid, and the next step can be performed.

[0047] The fourth step is to read the current external environment pressure P2 measured by the external pressure transmitter 3, and preliminarily determine the pressure difference dP between the gas storage tank 1 and the external environment as:

[0048] dP=|P2-P1|

[0049] If dP>1000 Pa, it is considered that the current pressure difference exceeds the measurement range of this device, and a measuring device with a larger measurement range needs to be replaced. If dP<1000 Pa, it is considered that the current pressure difference is within the measurement range of this device, and the next step can be performed.

[0050] The fifth step is to turn on the differential pressure transmitter 4. When the external environment absolute pressure value P2 displayed by the external pressure transmitter 3 is stable, the data displayed by the differential pressure transmitter 4 is read as the high-precision differential pressure value.

[0051] The present invention has an ingenious structural design, is easy to use, has a low production cost, and has high measurement accuracy. The air in the air storage bin can provide a reference pressure, providing a basis for measuring the pressure difference between the two environments, thereby increasing the measurement accuracy of the pressure difference, and can also be used as a pressure standard to accurately monitor changes in the surrounding environment. In addition, the present invention combines the technical advantages of the indirect method and the direct method for measuring the pressure difference, and can obtain high-precision measurement results even in situations where there is no reserved pressure difference measurement tube, and is suitable for various space environments.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision pressure difference measuring device, characterized in that: It includes a differential pressure transmitter, and the two sides of the differential pressure transmitter are respectively connected to the reference sampling detection component and the sampling detection component to be tested; the reference sampling detection component includes an air storage bin, and the air storage bin is used to store the reference space environment air to form a reference pressure value; the two ends of the air storage bin are respectively provided with an air storage bin air inlet pipe and an inner bin air path; air can enter the air storage bin through the air storage bin air inlet pipe, and the air storage bin air inlet pipe is provided with an air storage bin air inlet pipe valve, and the air storage bin air inlet pipe valve is used to control the opening and closing of the air storage bin air inlet pipe; the inner bin air path and the differential pressure transmitter The inner chamber gas circuit includes an inner chamber gas circuit main pipe, one end of which is connected to the gas storage bin, and the other end of which is connected to the inner chamber absolute pressure measurement branch pipe and the inner chamber pressure difference measurement branch pipe; the end of the inner chamber pressure difference measurement branch pipe away from the inner chamber gas circuit main pipe is connected to the differential pressure transmitter; the end of the inner chamber absolute pressure measurement branch pipe away from the inner chamber gas circuit main pipe is connected to the inner chamber pressure transmitter, and the inner chamber pressure transmitter can measure the air pressure in the gas storage bin; the sampling and detection component to be tested includes an external gas circuit, and the external gas circuit is connected to the external space ambient air , in order to detect the external environmental pressure value; the external gas circuit includes an external gas circuit main pipe, one end of which is connected to the external environment, and the other end of which is connected to an external absolute pressure measuring branch pipe and an external differential pressure measuring branch pipe; the end of the external differential pressure measuring branch pipe away from the external gas circuit main pipe is connected to a differential pressure transmitter; the end of the external absolute pressure measuring branch pipe away from the external gas circuit main pipe is connected to an external warehouse pressure transmitter, which can measure the air pressure of the external environment; the data displayed by the differential pressure transmitter is the pressure difference between the gas storage bin and the external air The pressure difference value of the room environment; the pipe diameters of the inner warehouse gas circuit main pipe and the external gas circuit main pipe are larger than the pipe diameters of the inner warehouse absolute pressure measurement branch pipe, the inner warehouse pressure difference measurement branch pipe, the external absolute pressure measurement branch pipe and the external pressure difference measurement branch pipe, so as to facilitate the rapid balance of the air pressure in each part; valves are arranged on the inner warehouse gas circuit main pipe, the inner warehouse absolute pressure measurement branch pipe, the inner warehouse pressure difference measurement branch pipe, the external gas circuit main pipe, the external absolute pressure measurement branch pipe and the external pressure difference measurement branch pipe. By opening and closing each valve, the air tightness of each part of the device can be checked one by one.

2. The high-precision pressure difference measuring device according to claim 1, characterized in that: The internal warehouse gas main pipe and the external gas main pipe use DN5-20 pipes; the internal warehouse absolute pressure measurement branch pipe, the internal warehouse pressure difference measurement branch pipe, the external absolute pressure measurement branch pipe and the external pressure difference measurement branch pipe use DN4-16 pipes.

3. The high-precision pressure difference measuring device according to claim 1, characterized in that: The measuring range of the internal pressure transmitter and the external pressure transmitter is ±500kPa~2000kPa, with an accuracy of 2%~5%; the measuring range of the differential pressure transmitter is ±0.5kPa~2.0kPa, with an accuracy of 0.5%~2%.

4. The high-precision differential pressure measuring device according to claim 1, characterized in that: The range of the internal pressure transmitter and the external pressure transmitter is ±1000 kPa, with an accuracy of 2%; the range of the differential pressure transmitter is ±1.0 kPa, with an accuracy of 1%.

5. A method for measuring differential pressure based on the high-precision differential pressure measuring device described in claim 1, characterized in that: The steps include: The first step is to start the device and conduct self-inspection to ensure that the pipelines and equipment are clean and unobstructed, and the pipelines and valves are connected intact and leak-free; The second step is to open the air inlet pipe valve of the air storage tank in a space environment and balance for about 1 minute until the absolute pressure value inside the air storage tank displayed by the internal tank pressure transmitter and the absolute pressure value of the external environment displayed by the external pressure transmitter are stable. At this time, the pressure difference ΔP measured by the differential pressure transmitter is 0, and then close the air inlet pipe valve of the air storage tank and the differential pressure transmitter; The third step is to move the device to another space environment to balance for about 1 minute, and continuously collect data for 1 minute to measure and calculate the gas storage tank leakage rate R. R=|P i -P0| / t Where P i is the end point pressure, P0 is the initial pressure, and t is the interval time; if the leakage rate R in the gas storage bin>1 Pa / min, it is considered that the leakage rate R does not meet the measurement requirements; if the leakage rate R in the gas storage bin≤1 Pa / min, it is considered that the leakage rate R meets the measurement requirements; If the leakage rate R does not meet the measurement requirements, it is considered that the airtightness of the gas storage bin is not good, and it is necessary to check and adjust the gas storage bin and the pipes and valves connected to it, and start again from the first step; if the leakage rate R meets the measurement requirements, it is considered that the airtightness of the gas storage bin is good, and the pressure value P1 measured by the internal bin pressure transmitter is valid, and the next step can be performed; The fourth step is to read the current external environment pressure P2 measured by the external pressure transmitter, and preliminarily determine the pressure difference dP between the gas storage tank and the external environment as: dP=|P2-P1| If dP>1000 Pa, it is considered that the current pressure difference exceeds the measurement range of this device, and a measuring device with a larger measurement range needs to be replaced; if dP<1000 Pa, it is considered that the current pressure difference is within the measurement range of this device, and the next step can be performed; Step 5. Turn on the differential pressure transmitter. When the absolute pressure value of the external environment displayed by the external pressure transmitter is stable, the data displayed by the differential pressure transmitter is the high-precision differential pressure value.

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