TWI655384B - Gas system automatically nippers - Google Patents

Abstract

The invention provides a gas system for automatically detecting a leak, and a pressure sensing unit is arranged between the upstream gas valve and the downstream gas valve which are connected to each other, and sequentially comprises the following detecting steps: (A) in the second combustion The gas valve is closed, or one of the closed, the pressure sensing unit detects a base pressure value; (B) detects a detected pressure value after a delay time or another gas valve is closed; (C) bases The pressure value is compared with the detected pressure value; (D) when the detected pressure value is greater than the base pressure value, an upstream gas valve leak warning signal is issued; when the detected pressure value is less than the base pressure value, a downstream gas valve leak is issued. Warning signal. By the above method, the invention can automatically detect whether air leakage occurs when the gas system is turned off, thereby improving the safety of the gas system and saving manpower.

Description

Gas system automatically detects leaks

The invention relates to a method for automatically detecting a gas leak in a gas system, and the technical content relates to utilizing a pressure sensing unit disposed between an upstream gas valve and a downstream gas valve connected to each other, and comparing the pressures detected at different times. The value is used to determine whether the two gas valves are leaking.

In recent years, gas has been widely exploited and applied to human life due to its abundant production, low price, convenient storage and transportation, and good energy utilization efficiency. For example, gas stoves, gas water heaters, and even turbine engine fuels and power generation in the home use gas as a fuel to promote the operation of various daily necessities. The popularity of gas appliances has brought convenience to life, and at the same time it has spawned many safety concerns that should be noted.

The gas itself as a fuel is not toxic to the human body and is easily dissipated. However, if it is used in a closed environment with poor ventilation, such as indoors or buildings, ships, etc., it is easy to accumulate gas in a narrow space and increase the gas concentration per unit volume. In the undetected situation, once a spark is encountered, it is easily ignited and detonated to cause casualties. Gas continues to leak without being noticed, which inevitably increases the fuel cost and wastes energy. Therefore, it is an important issue to be able to detect gas leaks frequently and safely.

The use of manual periodic security inspections can increase the safety of use to a certain extent, but it is not efficient for manpower. If the frequency of periodic manual inspection is increased, it is difficult to perform in practice, and in the event of a leak, it is difficult to immediately detect and notify the treatment, and at the same time, the manual operation can be exposed to a dangerous environment. Therefore, in order to improve the above-mentioned doubts, it is necessary to use a gas appliance having an automatic self-detection function to improve the safety of use, and it is necessary for various considerations.

In view of this, the inventors have accumulated years of research and practical experience in related fields, and have created a method for automatically detecting gas leakage by a gas system, and if necessary, can automatically detect whether the valve is leaking each time the gas system is turned off. It can improve the safety of the use of gas appliances, save labor costs, and reduce accidents that may occur due to the need for manual inspection.

The object of the present invention is to provide a method for automatically detecting a gas leak in a gas system, aiming at detecting a different time after the gas valve is closed by using a pressure sensing unit disposed between the upstream gas valve and the downstream gas valve that are connected to each other. The pressure difference at the point determines whether the upstream and downstream gas valves are leaking. By the above method, the present invention can automatically detect whether or not air leakage occurs when the gas system is turned off, thereby improving the safety of the gas system.

In order to achieve the above object, the present invention provides a method for automatically detecting a gas leak in a gas system, wherein a pressure sensing unit capable of detecting gas pressure is disposed between an upstream gas valve and a downstream gas valve that are in communication with each other. The method performs the following detection steps in sequence when the gas system is shut down: (A) after the upstream gas valve and the downstream gas valve are closed, the pressure sensing unit detects a base pressure value; (B) the pressure sensing unit Detecting a detected pressure value after a delay time; (C) comparing the detected pressure value with the base pressure value; and (D) issuing an upstream gas valve leak warning signal when the detected pressure value is greater than the base pressure value; When the detected pressure value is less than the base pressure value, a downstream gas valve air leak warning signal is issued.

The present invention further provides an implementation method for providing a pressure sensing unit capable of detecting gas pressure between an upstream gas valve and a downstream gas valve that communicate with each other. The method performs the following detections in sequence when the gas system is turned off. Step: (A) after the upstream gas valve is closed, the pressure sensing unit detects a base pressure value; (B) the downstream gas valve is closed after a delay time, and passes after a delay time after closing The pressure sensing unit detects a detected pressure value; (C) compares the detected pressure value with the base pressure value; and (D) sends an upstream gas valve leak when the detected pressure value is greater than the base pressure value Warning signal.

In the implementation, the step (D) performs a second detecting step when the next gas system is turned off when the detected pressure value is substantially equal to the base pressure value, and the second detecting step sequentially comprises: (E) burning in the downstream After the gas valve is closed, the pressure sensing unit detects a second base pressure value; (F) the upstream gas valve is closed after a delay time, and is detected by the pressure sensing unit after a delay time after closing a second detected pressure value; (G) comparing the second detected pressure value with the second base pressure value; (H) issuing a downstream gas valve leak when the second detected pressure value is less than the second base pressure value Gas alert signal.

The present invention further provides an implementation method for providing a pressure sensing unit capable of detecting gas pressure between an upstream gas valve and a downstream gas valve that communicate with each other. The method performs the following detections in sequence when the gas system is turned off. Step: (A) after the downstream gas valve is closed, the pressure sensing unit detects a base pressure value; (B) the upstream gas valve is closed after a delay time, and passes through a delay time after closing The pressure sensing unit detects a detected pressure value; (C) compares the detected pressure value with the base pressure value; and (D) sends a downstream gas valve leak warning when the detected pressure value is less than the base pressure value signal.

In the implementation, the step (D) performs a second detecting step when the next gas system is turned off when the detected pressure value is substantially equal to the base pressure value, and the second detecting step sequentially comprises: (E) burning in the upstream After the air valve is closed, the pressure sensing unit detects a second base pressure value; (F) the downstream gas valve is closed after a delay time, and is detected by the pressure sensing unit after a delay time after closing a second detected pressure value; (G) comparing the second detected pressure value with the second base pressure value; and (H) the second detected pressure value being greater than the second base pressure value to issue an upstream gas valve Air leak warning signal.

In implementation, the upper and lower gas valves have a chamber therebetween, the pressure sensing unit is a pressure sensor disposed in the chamber, and the gas system detects the resistance value of the pressure sensor before performing the detecting step, To compensate for the error caused by the temperature change of the pressure sensor.

In implementation, the upstream gas valve or the downstream gas valve is a moving coil proportional solenoid valve having a movable coil and a lifting film between the upstream gas valve and the downstream gas valve And a lifting diaphragm capable of receiving a displacement of the gas pressure to push the movable coil displacement, and the pressure sensing unit detects the gas pressure change by detecting the displacement amount of the movable coil.

In implementation, the moving coil proportional solenoid valve is provided with a temperature compensation loop, which can detect the resistance value to compensate for the error caused by the temperature sensing unit.

In implementation, the upstream gas valve or the downstream gas valve is a core-type proportional solenoid valve having an electromagnetic coil, a movable iron core, and an upstream gas valve and a downstream gas a lifting diaphragm between the valves, the lifting diaphragm is capable of receiving a top pressure of the gas pressure and pushing against the displacement of the movable core, and the pressure sensing unit detects the movable iron core The amount of displacement is used to detect changes in gas pressure.

In implementation, the iron core proportional solenoid valve is provided with a temperature compensation loop capable of detecting a resistance value to compensate for an error caused by a temperature change of the pressure sensing unit.

In the following, according to the technical means of the present invention, embodiments suitable for the present invention are listed, and the following description is in conjunction with the drawings:

As shown in the first figure, the present invention is a method for automatically detecting a gas leak in a gas system, the technical content is that between the upstream gas valve 10 and the downstream gas valve 20 on the mutually connected gas passages, a The pressure sensing unit 30 is configured to detect a gas pressure connecting the chamber 40 between the upstream and downstream gas valves 10 and 20; in practice, the pressure sensing unit 30 is a pressure sensor disposed in the chamber 40, and Before performing the detection step, the gas system should first detect the resistance value of the pressure sensor to compensate for the error caused by the temperature change of the pressure sensor. As shown in the figure, when the gas system is in operation, the gas passes through the one-way passage, and the gas inlet 50 sequentially passes through the upstream gas valve 10, the pressure sensing unit 30, and the downstream gas valve 20, and then the gas outlet. 51 is released and supplied to gas appliances (not shown).

The principle of automatically detecting the air leakage of the present invention is that when the gas system is closed, the upstream and downstream gas valves 10, 20 are in a closed state, and at this time, in the upstream part of the gas passage, the gas entering from the gas inlet 50 is entered. It is blocked by the upstream gas valve 10, and the downstream part of the gas passage is no longer supplied with gas after the downstream gas valve 20 is closed, so that the gas in the gas outlet 51 is instantaneously burned out by the gas appliance, and then the flame is extinguished. Therefore, the pressure at the position of the gas inlet 50 is much greater than the state of the gas outlet 51, and the gas pressure in the chamber 40 should theoretically remain stable.

At this time, since the gas supply source (not shown) connected to the gas inlet 50 has a high gas pressure, when the upstream gas valve 10 generates a leak, the gas will continue to pass through the upstream of the gas inlet 50. The gas valve 10 enters the chamber 40, however the downstream gas valve 20 remains in a closed state such that gas passing through the upstream gas valve 10 will continue to accumulate within the chamber 40, increasing the gas pressure within the chamber 40.

On the contrary, in the state where the upstream gas valve 10 is functioning normally, if the downstream gas valve 20 generates a leak, the gas sealed in the chamber 40 will continue to flow toward the relatively low pressure gas outlet 51 through the downstream gas valve 20. Out, the gas pressure in the chamber 40 is reduced.

In other words, when the upper and lower gas valves 10, 20 are closed, if the gas pressure in the chamber 40 increases, it means that the upstream gas valve 10 is leaking; if the gas pressure in the chamber 40 is reduced, it represents downstream. The gas valve 20 is leaking.

Based on the above principles, the first specific implementation steps of the method of the present invention are described below:

As shown in the second figure, the method of the present invention performs the following detection steps in sequence when the gas system is turned off:

(A) When both the upstream gas valve 10 and the downstream gas valve 20 are closed, the pressure sensing unit 30 disposed between the upstream gas valve 10 and the downstream gas valve 20 detects a base pressure value 60.

(B) After a delay time, the pressure sensing unit 30 detects a detected pressure value 61.

(C) The detected pressure value 61 is compared with the base pressure value 60.

(D) When the detected pressure value 61 is substantially equal to the base pressure value 60, it means that there is no air leakage in the upstream and downstream gas valves 10, 20; when the detected pressure value 61 is greater than the base pressure value 60, it means that the upstream gas valve 10 generates a leak. That is, an upstream gas valve air leakage warning signal 70 is issued; when the detected pressure value 61 is less than the basic pressure value 60, it indicates that the downstream gas valve 20 generates a leak, that is, a downstream gas valve air leakage warning signal 71 is issued.

By the above method, the present invention can set the detection step every time when the gas system is turned off, if necessary, to accurately detect whether the upstream and downstream gas valves 10 and 20 are leaking, and improve the overall combustion. The safety of the gas system.

It should be noted that, due to the different allowable leakage of gas valves in various countries, a leak reference has been set in the system. Therefore, the pressure change data detected by the pressure sensing unit 30 should exceed the national regulations. The allowed small leakage is the reference, and then the valve leakage warning signal in the step (D) is started.

The second implementation step of the method of the present invention is as shown in the third figure. The method is still based on the gas inlet 50, the upper and lower gas valves 10, 20, the chamber 40 and the gas outlet 51 when the gas system is turned off. The principle of gas pressure change between the two is designed. The difference is that when the gas system is closed, the upper and lower gas valves 10 and 20 are closed. The specific implementation method performs the following detection steps in sequence:

(A) After the upstream gas valve 10 is closed, the pressure sensing unit 30 detects a base pressure value 60. At this time, the downstream gas valve 20 has not been closed, and the remaining gas in the chamber 40 will continue to be released from the gas outlet 51 through the downstream gas valve 20. Since the upstream gas valve 10 is in a closed state, the gas in the chamber 40 cannot be replenished through the gas inlet 50, and the remaining gas will be extinguished immediately after being burned by the gas appliance, thereby presenting the pressure of the gas inlet 50 position. Far greater than the chamber 40 and the gas outlet 51, the base pressure value 60 detected by the pressure sensing unit 30 should be maintained at a steady state, i.e., substantially equal to or slightly lower than atmospheric pressure.

(B) The downstream gas valve 20 is closed after a delay time, and a detected pressure value 61 is detected by the pressure sensing unit 30 after a delay time after closing.

(C) comparing the detected pressure value 61 with the base pressure value 60;

(D) When the detected pressure value 61 is substantially equal to the base pressure value 60, it means that the upstream gas valve 10 has no air leakage; if the upstream gas valve 10 generates a leak, the gas will continue to be continuously ignited by the gas inlet 50. The gas valve 10 enters the chamber 40. At this time, since the downstream gas valve 20 is in a closed state after the step (B), the gas is continuously accumulated in the chamber 40 through the gas leakage upstream gas valve 10, thereby increasing Gas pressure within the chamber 40. Therefore, if the detected pressure value 61 is greater than the base pressure value 60, it means that the upstream gas valve 10 generates a leak, and an upstream gas valve air leak warning signal 70 is issued.

Since the above steps can only detect whether the upstream gas valve 10 is leaking, it is impossible to know whether the functional state of the downstream gas valve 20 is normal. Therefore, after the execution of the above detection step, if the upstream gas valve 10 has no air leakage condition, no warning or repair is required, and the next detection step can be performed when the gas system is closed again next time; the second detection The step is to detect whether the downstream gas valve 20 is normal, and includes:

(E) After the downstream gas valve 20 is closed, the pressure sensing unit 30 detects a second base pressure value 62; at this time, the gas in the chamber 40 is blocked by the downstream gas valve 20 to the gas outlet 51. The path, thus the gas pressure in the chamber 40 is substantially equal to the pressure of the gas supply (not shown), and is much larger than the gas outlet 51, and the second base pressure value 62 detected by the pressure sensing unit 30. It should be maintained in a steady state, that is, approximately equal to the gas inlet 50.

(F) the upstream gas valve 10 is closed after a delay time, and after a delay time after the closure, a second detection pressure value 63 is detected by the pressure sensing unit 30;

(G) comparing the second detected pressure value 63 with the second base pressure value 62;

(H) when the second detected pressure value 63 is substantially equal to the second base pressure value 62, indicating that the downstream gas valve 20 has no air leakage; if the downstream gas valve 20 generates a leak, the gas sealed in the chamber 40 will Continuously discharged through the downstream gas valve 20 toward the relatively low pressure gas outlet 51, causing the gas pressure in the chamber 40 to gradually decrease, so when the second detected pressure value 63 is less than the second base pressure value 62, It is determined that the downstream gas valve 20 is leaking and a downstream gas valve leak warning signal 71 is issued.

By the above method, the present invention can set the (A)-(D) detecting step and the (E)-(F) second detecting step in turn when the gas system is turned off, if necessary, to accurately detect Whether the upstream and downstream gas valves 10 and 20 have air leakage conditions improves the safety of the overall gas system. Similarly, according to the leak reference that has been set in the system, the pressure change data detected by the pressure sensing unit 30 should be started (D) or (based on the small leakage allowed by the country regulations). H) In the step of reporting the valve leak warning signal.

The third implementation step of the method of the present invention is as shown in the fourth figure. The method is still based on the gas inlet 50, the upper and lower gas valves 10, 20, the chamber 40 and the gas outlet 51 when the gas system is turned off. The principle of gas pressure change between the two is designed, and the upstream and downstream gas valves 10 and 20 are closed. The difference is that the order of closing the upper and lower gas valves 10 and 20 is reversed. The specific implementation method performs the following detection steps in sequence; the principle of each step is the same as the second embodiment, and no further details are provided herein.

(A) After the downstream gas valve 20 is closed, the pressure sensing unit 30 detects a base pressure value 60.

(B) the upstream gas valve 10 is closed after a delay time, and after a delay time after closing, the pressure sensing unit 30 detects a detected pressure value 61;

(C) comparing the detected pressure value 61 with the base pressure value 60;

(D) When the detected pressure value 61 is substantially equal to the base pressure value 60, it indicates that the downstream gas valve 20 has no air leakage; when the detected pressure value 61 is smaller than the base pressure value 60, it can be determined that the downstream gas valve 20 is leaking. Gas and a downstream gas valve air leak warning signal 71 is issued.

Similarly, the above steps can only detect whether the downstream gas valve 20 is leaking, and it is impossible to know whether the functional state of the upstream gas valve 10 is normal. Therefore, after the execution of the above detecting step, when the next gas system is closed again, the second detecting step may be performed, and the second detecting step sequentially comprises:

(E) After the upstream gas valve 10 is closed, the pressure sensing unit 30 detects a second base pressure value 62.

(F) The downstream gas valve 20 is closed after a delay time, and a second detected pressure value 63 is detected by the pressure sensing unit 30 after a delay time after the closing.

(G) comparing the second detected pressure value 63 with the second base pressure value 62;

(H) when the second detected pressure value 63 is substantially equal to the second base pressure value 62, indicating that the upstream gas valve 10 has no air leakage; if the second detected pressure value 63 is greater than the second base pressure value 62, the upstream is determined The gas valve 10 leaks and sends an upstream gas valve leak warning signal 70.

As shown in the fifth and sixth figures, the pressure sensing unit 30 is a pressure sensor, and any gas system having an upstream gas valve 10, a downstream gas valve 20, and a chamber 40 therebetween may be used. The pressure sensor is additionally provided for automatic detection by the gas system. It is worth mentioning that the manner of setting the pressure sensing unit 30 is not limited to being disposed only in the chamber 40 between the upstream and downstream gas valves 10, 20, and some can adjust the opening degree by the magnitude of the electric power, and has A solenoid valve that can react and compensate for changes in gas pressure to maintain a stable gas flow rate, such as a coil type proportional solenoid valve or a core type proportional solenoid valve (this is a known technique, not further described) itself, That is, a precise pressure sensing unit 30, therefore, the present invention includes the following two embodiments in addition to the pressure sensor additionally provided in the chamber 40 in the arrangement of the pressure sensing unit 30.

As shown in the seventh figure, the upstream gas valve 10 or the downstream gas valve 20 may be a moving coil type proportional solenoid valve 80 having a movable coil 81 and an upstream A lifting diaphragm 82 between the gas valve 10 and the downstream gas valve 20. When the gas passes through the moving coil type proportional solenoid valve 80, the lifting diaphragm 82 can receive the displacement of the gas pressure in the chamber and push the displacement of the movable coil 81, and the gas pressure sensing unit 30, the gas pressure change can be detected by detecting the displacement amount of the movable coil 81.

When the upstream gas valve 10 generates a leak, the gas continues to enter and accumulate in the chamber 40 through the upstream gas valve 10 from the gas inlet 50, increasing the gas pressure within the chamber 40. At this time, the gas pressure in the chamber 40 is pushed against the displacement of the lifting diaphragm 82 and the movable coil 81, and the pressure sensing unit 30 can detect the displacement of the movable coil 81 and report an upstream gas. Valve leak warning signal. Conversely, when the downstream gas valve 20 generates a leak, the gas in the chamber 40 continues to pass through the downstream gas valve 20 and is released toward the relatively low pressure gas outlet 51. The pressure of the gas in the chamber 40 is reduced to displace the lifting diaphragm 82. The pressure sensing unit 30 can detect the displacement of the movable coil 81 and report a downstream gas valve leakage warning signal.

As shown in the eighth figure, the upstream gas valve 10 or the downstream gas valve 20 is a core-type proportional solenoid valve 90 having an electromagnetic coil 91 and a movable iron core. 92, and a lifting diaphragm 93 between the upstream gas valve 10 and the downstream gas valve 20, the lifting diaphragm 93 can receive the top pressure of the gas pressure in the chamber 40 and push the movable core Similarly, the gas pressure sensing unit 30 can detect the gas pressure change by detecting the displacement amount of the movable iron core 92.

As a result, when the upstream gas valve 10 generates a leak, the gas continues to enter and accumulate in the chamber 40 through the upstream gas valve 10 from the gas inlet 50, increasing the gas pressure in the chamber 40. At this time, the gas pressure in the chamber 40 will be pushed against the displacement of the lifting diaphragm 93, the displacement of the movable core 92 toward the outside of the chamber 40, and an upstream gas valve leakage warning signal is reported. Conversely, when the downstream gas valve 20 generates a leak, the gas in the chamber 40 continues to pass through the downstream gas valve 20 and is released toward the relatively low pressure gas outlet 51. The gas pressure in the chamber 40 is reduced, the movable core 92 is displaced toward the chamber 40, and a downstream gas valve leak warning signal is reported.

Similarly, in order to avoid the error caused by the pressure sensing unit 30 sensing the pressure change, the embodiment of the moving coil type proportional solenoid valve or the iron core proportional solenoid valve can also add a temperature compensation loop to compensate the temperature change by using the detection resistance value. The displacement of the movable coil or the movable iron core is prevented from being affected by the temperature change, thereby affecting the pressure value detected by the pressure sensing unit 30 and correcting the error.

The above description of the embodiments and the drawings are merely illustrative of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and should be similar or identical to the objects, structures, devices, features, etc. of the present invention. Having claimed the scope of the invention, it is hereby stated.

10‧‧‧Upstream gas valve

20‧‧‧ Downstream gas valve

30‧‧‧ Pressure sensing unit

40‧‧‧ chamber

50‧‧‧ gas inlet

51‧‧‧ gas export

60‧‧‧Basic pressure values

61‧‧‧Detecting pressure values

62‧‧‧ second base pressure value

63‧‧‧Second detection pressure value

70‧‧‧Upstream gas valve leak warning signal

71‧‧‧ Downstream gas valve leak warning signal

80‧‧‧ moving coil proportional solenoid valve

81‧‧‧ movable coil

82‧‧‧ Lifting diaphragm

90‧‧‧core core proportional solenoid valve

91‧‧‧Electromagnetic coil

92‧‧‧ movable core

93‧‧‧ Lifting diaphragm

First figure: Schematic diagram of the system configuration of the present invention. Second Figure: Schematic diagram of the detection steps of the first embodiment of the method of the present invention. Third: Schematic diagram of the detection steps of the second embodiment of the method of the present invention. Fourth: Schematic diagram of the detection steps of the third embodiment of the method of the present invention. Fig. 5 is a schematic view showing the pressure sensing unit of the present invention installed in a chamber. Figure 6: Schematic diagram of the pressure sensing unit of the present invention installed in a chamber or solenoid valve. Figure 7: Schematic diagram of the pressure sensing unit of the present invention disposed on a moving coil type proportional solenoid valve. Eighth: Schematic diagram of the pressure sensing unit of the present invention disposed on a core-type proportional solenoid valve.

Claims (10)

A method for automatically detecting a gas leak in a gas system is to provide a pressure sensing unit capable of detecting gas pressure between an upstream gas valve and a downstream gas valve that are connected to each other, wherein the gas system is closed when the gas system is shut down The following detection steps are performed: (A) after the upstream gas valve and the downstream gas valve are closed, the pressure sensing unit detects a base pressure value; (B) the pressure sensing unit detects a delay time after a delay time Detecting a pressure value; (C) comparing the detected pressure value with the base pressure value; and (D) issuing an upstream gas valve air leak warning signal when the detected pressure value is greater than the base pressure value; When the pressure value is less than the base pressure value, a downstream gas valve air leakage warning signal is issued. A method for automatically detecting a leak in a gas system is to provide a pressure sensing unit capable of detecting a change in gas pressure between an upstream gas valve and a downstream gas valve that are in communication with each other. The following detection steps are sequentially performed: (A) after the upstream gas valve is closed, the pressure sensing unit detects a base pressure value; (B) the downstream gas valve is closed after a delay time, and after being closed, Detecting a detected pressure value by the pressure sensing unit after a delay time; (C) comparing the detected pressure value with the base pressure value; and (D) when the detected pressure value is greater than the base pressure value An upstream gas valve air leak warning signal is issued. A method for automatically detecting a leak in a gas system according to claim 2, wherein the step (D) is performed a second time when the next gas system is turned off when the detected pressure value is substantially equal to the base pressure value a detecting step, the second detecting step sequentially comprises: (E) after the downstream gas valve is closed, the pressure sensing unit detects a second base pressure value; (F) the upstream gas valve is in a delay time After being closed, and after a delay period, a second detection pressure value is detected by the pressure sensing unit; (G) comparing the second detected pressure value with the second base pressure value; (H) issuing a downstream gas valve leak warning signal when the second detected pressure value is less than the second base pressure value. A method for automatically detecting a leak in a gas system is to provide a pressure sensing unit capable of detecting a change in gas pressure between an upstream gas valve and a downstream gas valve that are in communication with each other. The following detection steps are sequentially performed: (A) after the downstream gas valve is closed, the pressure sensing unit detects a base pressure value; (B) the upstream gas valve is closed after a delay time, and after being closed, Detecting a detected pressure value by the pressure sensing unit after a delay time; (C) comparing the detected pressure value with the base pressure value; and (D) issuing the detected pressure value when the detected pressure value is less than the base pressure value A downstream gas valve leak warning signal. The method of claim 4, wherein the step (D) is performed for the second time when the next gas system is turned off when the detected pressure value is substantially equal to the base pressure value. a detecting step, the second detecting step sequentially comprises: (E) after the upstream gas valve is closed, the pressure sensing unit detects a second base pressure value; (F) the downstream gas valve is in a delay time After closing, and detecting a second detected pressure value through the pressure sensing unit after a delay time; (G) comparing the second detected pressure value with the second base pressure value; and (H) And sending an upstream gas valve air leakage warning signal when the second detected pressure value is greater than the second base pressure value. A method for automatically detecting a leak in a gas system according to any one of claims 1 to 5, wherein a chamber is provided between the upstream gas valve and the downstream gas valve, and the pressure sensing unit is The pressure sensor is disposed in the chamber, and the resistance value of the pressure sensor is detected before the detecting step to compensate for the error caused by the temperature change of the pressure sensor. The method for automatically detecting a leak in a gas system according to any one of claims 1 to 5, wherein the upstream gas valve or the downstream gas valve is a moving coil type proportional solenoid valve, the moving coil type The proportional solenoid valve has a movable coil and a lifting diaphragm between the upstream gas valve and the downstream gas valve, and the lifting diaphragm can receive the pressure of the gas pressure to push against the movable coil Displacement, and the pressure sensing unit detects a gas pressure change by detecting a displacement amount of the movable coil. The method of claim 7, wherein the moving coil type proportional solenoid valve is provided with a temperature compensation loop, and the temperature compensation loop can detect the resistance value to compensate the temperature sensing unit for temperature change. The error caused. The method for automatically detecting a leak in a gas system according to any one of claims 1 to 5, wherein the upstream gas valve or the downstream gas valve is a core-type proportional solenoid valve, the core The proportional solenoid valve has an electromagnetic coil, a movable iron core, and a lifting diaphragm between the upstream gas valve and the downstream gas valve, and the lifting diaphragm can receive the pressure of the gas pressure. The displacement of the movable core is pushed, and the pressure sensing unit detects the change in the gas pressure by detecting the displacement amount of the movable core. The method of claim 9, wherein the gas core proportional solenoid valve is provided with a temperature compensation loop, and the temperature compensation loop can detect the resistance value to compensate the temperature sensing unit due to temperature change. Error.