On-site air tightness detection system and detection method for mouth of civil air defense project

Abstract

The invention relates to the technical field of civil air defense engineering detection, in particular to a civil air defense engineering mouth site air tightness detection system and method, and the system comprises a reserved pipe which is arranged in an engineering mouth wall body and is used for communicating the spaces at the two sides of the engineering mouth wall body, and the two ends of the reserved pipe are provided with detachable plugs; the smoke generating device is used for inputting smoke into the mouth part of the civil air defense project through a reserved pipe outside the mouth part of the civil air defense project or generating smoke in the mouth part of the civil air defense project; the air pumping device is used for pumping air into the mouth of the civil air defense project through the reserved pipe outside the mouth of the civil air defense project; and the air pressure measuring device is used for measuring air pressure in the mouth of the civil air defense project in real time. According to the method, smoke is generated in the closed mouth of the civil air defense project and air inflation is carried out, so that the interior of the mouth of the civil air defense project reaches certain air pressure, whether the overall air tightness of the mouth of the civil air defense project is qualified or not is judged by observing the air pressure descending speed, and a specific leakage point is found by observing the smoke leakage position.

Description

Technical Field

[0001] The present invention relates to the technical field of civil air defense project detection, and in particular to an on-site air tightness detection system and method for the opening of a civil air defense project. Background Art

[0002] The entrance of a civil air defense project (entrance passage) is the entrance and exit for personnel and equipment. Each civil air defense project has more than two entrances and exits. The entrance of a civil air defense project is equipped with protective facilities, mainly including protective sealing, gas filtration and ventilation, decontamination, nuclear automatic alarm control and dose monitoring and testing facilities, which are the material basis for the effective protection of personnel sheltered in the civil air defense project.

[0003] Protective enclosed facilities include: protective doors, protective enclosed doors, enclosed doors and anti-poison passages. Their function is to prevent contaminated air from entering the civil air defense project through the entrances and exits.

[0004] Gas filtering and ventilation facilities are generally composed of wind wave elimination equipment, dust filters, filter absorbers, air ducts, closed valves and fans. Gas filtering and ventilation facilities are the basic content of civil air defense protection facilities. They mainly play the role of filtering smoke, toxic mist and absorbing toxic agent vapor, and sending the purified clean air into the inner room of the civil air defense project through the fan through the pipeline for personnel to breathe.

[0005] The decontamination facilities include decontamination doors, disinfectants and decontamination equipment, which are used to conduct local or whole-body decontamination on people entering the project to avoid bringing radioactive dust and toxic agents into the civil air defense project, thereby ensuring the safety of people in the project.

[0006] The nuclear automatic alarm control facility is the nerve center of civil air defense projects to protect against nuclear and chemical weapons attacks. After being attacked by nuclear and chemical weapons, it can automatically sound an alarm, stop fans, and close valves, thereby preventing radioactive dust and toxic agents from entering the civil air defense project.

[0007] Dose monitoring laboratory facilities are used to identify the pollution of air, food, water, etc. inside and outside civil defense projects.

[0008] Civil air defense doors and entrances are an important part of civil air defense projects. They are the only way for personnel and equipment to enter and exit during wartime. They also have the function of preventing nuclear, chemical, biological and other toxic and harmful gases from entering the interior of civil air defense projects during wartime. Their airtightness will directly affect the protective performance of the entire project. Therefore, on-site testing of the airtightness of civil air defense doors is of great significance.

[0009] The existing technology is mostly to conduct air tightness detection on civil air defense doors. There are two detection methods. Method 1: install the civil air defense door on a detection platform to conduct air tightness detection on it; Method 2: add a closed space on the basis of the civil air defense door that has been installed at the civil air defense project site. For example, wrap the door seam of the civil air defense door with sealing material to form a closed space, pressurize the closed space and observe it at a constant pressure.

[0010] In addition to the gap of the civil air defense door, there may be other leakage points in the internal passage of the civil air defense door, such as wire reserved pipes for lighting equipment or ventilation equipment, floor drains, etc. Even if the above methods detect that the air tightness of the civil air defense door is qualified, it cannot guarantee the air tightness of other facilities in the entrance of the civil air defense project. Therefore, there is an urgent need for a system and / or detection method for on-site air tightness detection of the entrance of the civil air defense project, which can detect whether the overall air tightness of the entrance of the civil air defense project is qualified, and detect the specific leakage points when it is unqualified. Summary of the invention

[0011] In view of this, the present invention provides an on-site air tightness detection system for the openings of civil air defense projects, aiming to solve the problem that the prior art cannot detect on-site whether the overall air tightness of the openings of civil air defense projects is qualified, and cannot detect the specific leakage point when it is unqualified.

[0012] In order to solve the above problems, the present invention provides an on-site air tightness detection system for the opening of a civil air defense project, comprising: The reserved pipe is arranged in the wall of the project entrance separating the entrance of the civil air defense project from the inner room of the civil air defense project, and / or in the wall of the project entrance separating the entrance of the civil air defense project from the outside of the civil air defense project, and is used to connect the spaces on both sides of the wall of the project entrance, and both ends are provided with removable plugs; A smoke generating device, used to input smoke into the civil air defense project opening through the reserved pipe outside the civil air defense project opening, or used to generate smoke inside the civil air defense project opening; A gas pumping device, used for pumping gas into the opening of the civil air defense project through the reserved pipe outside the opening of the civil air defense project; The air pressure measuring device is used to measure the air pressure inside the opening of the civil air defense project in real time.

[0013] Optionally, the detection system also includes a thermal imaging device for observing air leakage at the door gap of the civil air defense door outside the entrance of the civil air defense project.

[0014] Optionally, the detection system further includes a power supply and a resistance wire connected to form a loop, wherein the resistance wire is arranged along the door gap of the civil air defense door to heat the airflow at the door gap.

[0015] Optionally, the detection system also includes a pulse gas tank, a compressed gas supply device and a controller, the compressed gas supply device is located outside the entrance of the civil air defense project, and the pulse gas tank is located inside the entrance of the civil air defense project. The gas outlet end of the pulse gas tank is provided with a valve, and the gas inlet end is connected to the gas outlet end of the compressed gas supply device through a pipeline and the reserved pipe. The valve and the air pressure measuring device are both electrically connected to the controller, and the controller is suitable for controlling the valve to open intermittently when the air pressure value measured by the air pressure measuring device reaches a preset value.

[0016] Optionally, the detection system also includes an airbag that can maintain pressure after being inflated, and can occupy the space inside the opening of the civil air defense project after being inflated.

[0017] Optionally, there are multiple reserved pipes, which are centrally arranged on the wall of the project opening.

[0018] Another object of the present invention is to propose an on-site air tightness detection method for the opening of a civil air defense project, comprising providing the above-mentioned on-site air tightness detection system for the opening of a civil air defense project; using a smoke generating device to generate smoke in the opening of the civil air defense project; connecting an air pumping device to a reserved pipe through a pipeline to pump air into the opening of the civil air defense project, and stopping the air pumping when the air pressure value measured by the air pressure measuring device reaches a first preset value; within a specified time, if the measured air pressure value drops by more than a specified value, the air tightness of the opening of the civil air defense project is judged to be unqualified, and if the measured air pressure value drops by no more than a specified value, the air tightness of the opening of the civil air defense project is judged to be qualified; and finding the location of the unqualified seal based on the leakage point.

[0019] Optionally, the detection method further provides a resistance wire and a thermal imaging device; the resistance wire is arranged in a gap where air leakage may occur or at the mouth of the gap; the thermal imaging device is used to find the hot air flow overflowing from the gap to determine the air leakage point.

[0020] Optionally, the detection method also provides an airbag that can be inflated and maintained under pressure; before the detection begins and the protective door is not closed, the airbag is inflated and the pressure is maintained in the opening of the civil air defense project, or after the detection begins and the protective door is closed, the airbag is inflated and the pressure is maintained through a pipeline and the reserved tube.

[0021] Optionally, the detection method also provides a pulse gas tank; when it is determined that the air tightness of the opening of the civil air defense project is unqualified, the pump air device is started to continue inflating so that the air pressure at the opening of the civil air defense project reaches a second preset value, and the second preset value is greater than the first preset value; the pulse gas tank is started to intermittently exhaust air in the opening of the civil air defense project, and the leakage point is found at the same time.

[0022] Compared with the prior art, the technical solution of the present invention has the following advantages: 1. By generating smoke and inflating in the closed entrance of the civil air defense project, a certain air pressure is reached in the entrance of the civil air defense project. The air tightness of the entire entrance of the civil air defense project is judged by observing the speed of the air pressure drop, and the specific leakage point is found by observing the location of the smoke leakage. It is not limited to the air tightness detection and leakage point finding of civil air defense doors, but other facilities in the entrance of the civil air defense project can also be tested for air tightness and leakage point finding in this way.

[0023] 2. When smoke is generated by the smoke generating device, it is usually accompanied by heat generation. The use of thermal imaging devices can quickly find the location of smoke leakage.

[0024] 3. In order to prevent the heat of smoke from being transferred to the walls or metal parts of the project entrance, an energized resistance wire is used to heat the air where the smoke may overflow. When the smoke overflows, the hot air at the corresponding position will flow, so that it can be quickly discovered by the thermal imaging device.

[0025] 4. By using an airbag that can be inflated and maintained under pressure to occupy a large amount of space in the opening of the civil air defense project, the airbag can be inflated before detection or while performing other operations, which can greatly shorten the time to inflate the opening of the civil air defense project to the specified air pressure and speed up the detection speed.

[0026] 5. When it is determined that the air tightness of the opening of the civil air defense project is unqualified, increase the air pressure inside the opening of the civil air defense project, and use pulse gas tanks for pulse exhaust, so that the high air pressure inside the opening of the civil air defense project intermittently impacts the weak air tightness, allowing more smoke to overflow from the weak air tightness, so as to quickly find the leakage location. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a schematic diagram of the layout of the civil air defense project and the positions of the reserved pipes and civil air defense doors in the embodiment.

[0029] In the figure: the entrance of the civil air defense project 1, the reserved pipe 2, and the civil air defense door 3. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the description of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Unless otherwise clearly specified and limited, the terms "disposed", "installed", "connected" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front”, “back”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of description and simplified description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] The terms "first", "second", "third", etc. are merely used to distinguish elements of similar nature, and do not indicate or imply relative importance or a particular order.

[0034] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of the elements listed and may also include additional elements not expressly listed.

[0035] Example 1 Please refer to Figure 1 The present invention provides an on-site air tightness detection system for the entrance of a civil air defense project, comprising a reserved pipe 2, a smoke generating device, an air pumping device and an air pressure measuring device; wherein the reserved pipe 2 is cast in advance in the wall of the entrance of the project, and can be arranged in the wall of the entrance of the project separated from the entrance of the civil air defense project 1 and the inner room of the civil air defense project, or can be arranged in the wall of the entrance of the project separated from the entrance of the civil air defense project 1 and the outside of the civil air defense project, and is used to connect the space on both sides of the wall of the entrance of the project, and both ends are provided with detachable plugs, which are in a blocked state when not in use; the air pumping device can adopt an air compressor or a compressed gas tank, and is arranged in the entrance of the civil air defense project Outside the mouth 1, it is used to pump gas into the mouth 1 of the civil air defense project through the reserved pipe 2 outside the mouth 1 of the civil air defense project, and open the plug to connect the pumping device with the reserved pipe 2 with a pipeline; the smoke generating device is also arranged outside the mouth 1 of the civil air defense project, and can also be arranged inside the mouth 1 of the civil air defense project, and input smoke into the mouth 1 of the civil air defense project through the reserved pipe 2 outside the mouth 1 of the civil air defense project, or directly generate smoke in the mouth 1 of the civil air defense project; the air pressure measuring device is preferably arranged on the pipeline connecting the pumping device to the reserved pipe 2. Since the pipeline is connected to the mouth 1 of the civil air defense project, the air pressure in the mouth 1 of the civil air defense project can be measured in real time.

[0036] The embodiment of the present invention generates smoke and inflates air in the closed entrance 1 of the civil air defense project to make a certain air pressure in the entrance 1 of the civil air defense project, and judges whether the overall air tightness of the entrance 1 of the civil air defense project is qualified by observing the speed of the air pressure drop, and finds the specific leakage point by observing the position of the smoke leakage. It is not only limited to the air tightness detection and leakage point finding of civil air defense doors, but other facilities in the entrance 1 of the civil air defense project can also be tested for air tightness and leakage point finding in this way.

[0037] Specifically, there are multiple reserved pipes 2, and different devices can be connected to the corresponding reserved pipes 2 and work simultaneously; and they are concentrated on the wall of the project entrance, for example, above the civil defense door 3, and can also be set at other positions on the wall of the project entrance, and all reserved pipes 2 are evenly spaced and parallel to each other.

[0038] Furthermore, the above-mentioned on-site air tightness detection system for the entrance of the civil air defense project also includes a thermal imaging device, which is used to observe the air leakage at the door gap of the civil air defense door 3 outside the entrance 1 of the civil air defense project. When the smoke generating device generates smoke, it is generally accompanied by the generation of heat. When the smoke with heat overflows at the door gap, a hot air flow will be generated. The thermal imaging device can be used to quickly find the smoke leakage location.

[0039] In addition, this embodiment also relates to a method for detecting air tightness of an opening of a civil air defense project on site, providing any device or component involved in the above detection system, and the detection steps are as follows: The first step is to use a smoke generating device to generate smoke in the opening 1 of the civil air defense project; The second step is to connect the air pumping device to the reserved pipe 2 through a pipeline, pump air into the civil air defense project opening 1, and stop pumping air when the air pressure value measured by the air pressure measuring device reaches a first preset value; The third step is that within the specified time, if the measured air pressure value decreases by more than the specified value, the air tightness of the civil air defense project opening 1 is judged to be unqualified; if the measured air pressure value decreases by no more than the specified value, the air tightness of the civil air defense project opening 1 is judged to be qualified; if it is unqualified, proceed to the next step; The fourth step is to locate the leakage point at the position where the smoke overflows from the opening 1 of the civil air defense project, find the position where the sealing fails according to the leakage point, and take corresponding remedial measures to enhance the sealing.

[0040] The embodiment of the present invention preferably uses nitrogen to inflate the opening 1 of the civil air defense project, because nitrogen has the advantage of strong permeability.

[0041] Example 2 This embodiment provides a system for detecting air tightness of the opening of a civil air defense project on the basis of the embodiment 1. Figure 1Furthermore, the on-site air tightness detection system for the entrance of the civil air defense project also includes a power supply and a resistance wire. The power supply and the resistance wire are connected to form a loop so that the resistance wire generates heat and thus heats the air; the resistance wire is arranged along the door gap of the civil air defense door 3, and the resistance wire can also be embedded in the gaps of other facilities in the entrance 1 of the civil air defense project where air leaks may occur. If it is inconvenient to embed the resistance wire in the gap, the resistance wire is fixed at the mouth of the gap with glue, so that the airflow overflowing from the gap will flow through the resistance wire and be heated, which is used to heat the airflow at the door gap.

[0042] The purpose of using resistance wire to heat the air is to prevent the heat of the smoke from being transferred to the wall or metal parts of the project entrance. The air where the smoke may overflow is heated by the energized resistance wire. When the smoke overflows, the hot air at the corresponding position flows, so that it can be quickly discovered by the thermal imaging device.

[0043] Furthermore, the above-mentioned on-site air tightness detection system for the entrance of the civil air defense project also includes a pulse gas tank, a compressed gas supply device and a controller. The compressed gas supply device is located outside the entrance of the civil air defense project 1, and the pulse gas tank is located inside the entrance of the civil air defense project 1. The gas outlet of the pulse gas tank is provided with a valve, and the gas inlet end is connected to the gas outlet of the compressed gas supply device through a pipeline and a reserved pipe 2. The valve and the air pressure measuring device are both electrically connected to the controller. The controller is suitable for controlling the valve to open intermittently when the air pressure value measured by the air pressure measuring device reaches a preset value. The compressed gas supply device can use an air compressor or a compressed gas tank.

[0044] When it is determined that the air tightness of the opening 1 of the civil air defense project is unqualified, the air pressure inside the opening 1 of the civil air defense project is increased, and pulse exhaust is performed using a pulse gas cylinder to make the high air pressure inside the opening 1 of the civil air defense project intermittently impact the weak air tightness, allowing the smoke to overflow from the weak air tightness in larger quantities, so as to quickly find the leakage location.

[0045] Furthermore, the above-mentioned on-site air tightness detection system for the entrance of the air defense project also includes an airbag that can be inflated and maintained under pressure, which is arranged in the entrance of the air defense project 1 and is used to occupy the space in the entrance of the air defense project 1 after being inflated. By using the airbag that can be inflated and maintained under pressure to occupy a large amount of space in the entrance of the air defense project 1, the airbag can be inflated before the detection or while performing other operations, which can greatly shorten the time for the entrance of the air defense project 1 to be inflated to a specified air pressure and speed up the detection speed.

[0046] In addition, this embodiment also relates to a method for detecting air tightness of an opening of a civil air defense project on site, providing any device or component involved in the above detection system, and the detection steps are as follows: The first step is to use a smoke generating device to generate smoke in the opening 1 of the civil air defense project; The second step is to connect the air pumping device to the reserved pipe 2 through a pipeline, pump air into the civil air defense project opening 1, and stop pumping air when the air pressure value measured by the air pressure measuring device reaches a first preset value; The third step is that within the specified time, if the measured air pressure value decreases by more than the specified value, the air tightness of the civil air defense project opening 1 is judged to be unqualified; if the measured air pressure value decreases by no more than the specified value, the air tightness of the civil air defense project opening 1 is judged to be qualified; if it is unqualified, proceed to the next step; The fourth step is to find the location where the seal fails based on the leakage point, and take corresponding remedial measures to enhance the sealing.

[0047] Optionally, the fourth step of the above detection method specifically includes the following two steps: 1. placing a resistance wire in a possible leaking gap or at the mouth of the gap; 2. using a thermal imaging device to find the hot air flow overflowing from the gap to determine the leak point.

[0048] Optionally, the fourth step of the above-mentioned detection method specifically includes the following two steps: 1. When it is determined that the air tightness of the entrance 1 of the civil air defense project is unqualified, start the air pump device to continue inflating so that the air pressure of the entrance 1 of the civil air defense project reaches a second preset value, and the second preset value is greater than the first preset value; 2. Start the pulse gas tank to intermittently exhaust air in the entrance 1 of the civil air defense project, and look for the leakage point at the same time.

[0049] Optionally, in the above-mentioned detection method, before the detection starts and the protective door is not closed, an airbag is set in the opening 1 of the civil air defense project, and the airbag is inflated and the pressure is maintained; or after the detection starts and the protective door is closed, the airbag is inflated and the pressure is maintained through a pipeline and a reserved tube 2, that is, an air pump and one end of the reserved tube 2 are connected through a pipeline, and the other end of the reserved tube 2 is connected to the airbag through another pipeline, the air pump is started to inflate, a valve can be set on the pipeline, and the valve is closed to maintain the pressure.

[0050] The embodiment of the present invention preferably uses nitrogen to inflate the opening 1 of the civil air defense project, because nitrogen has the advantage of strong permeability.

[0051] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A system for detecting air tightness of civil air defense project openings on site, characterized in that: include: The reserved pipe is arranged in the wall of the project entrance separating the entrance of the civil air defense project from the inner room of the civil air defense project, and / or in the wall of the project entrance separating the entrance of the civil air defense project from the outside of the civil air defense project, and is used to connect the spaces on both sides of the wall of the project entrance, and both ends are provided with removable plugs; A smoke generating device, used to input smoke into the entrance of the civil air defense project through the reserved pipe outside the entrance of the civil air defense project, or used to generate smoke inside the entrance of the civil air defense project; A gas pumping device, used for pumping gas into the opening of the civil air defense project through the reserved pipe outside the opening of the civil air defense project; The air pressure measuring device is used to measure the air pressure inside the opening of the civil air defense project in real time.

2. According to claim 1, the on-site air tightness detection system for the opening of a civil air defense project is characterized in that: It also includes a thermal imaging device, which is used to observe air leakage at the gap of the civil air defense door outside the entrance of the civil air defense project.

3. According to claim 2, the on-site air tightness detection system for the opening of a civil air defense project is characterized in that: It also includes a power supply and a resistance wire connected to form a loop. The resistance wire is arranged along the door gap of the civil air defense door and is used to heat the airflow at the door gap.

4. The on-site air tightness detection system for the opening of a civil air defense project according to claim 1 is characterized in that: It also includes a pulse gas tank, a compressed gas supply device and a controller. The compressed gas supply device is located outside the entrance of the civil air defense project, and the pulse gas tank is located inside the entrance of the civil air defense project. The gas outlet end of the pulse gas tank is provided with a valve, and the gas inlet end is connected to the gas outlet end of the compressed gas supply device through a pipeline and the reserved pipe. The valve and the air pressure measuring device are both electrically connected to the controller. The controller is suitable for controlling the valve to open intermittently when the air pressure value measured by the air pressure measuring device reaches a preset value.

5. According to claim 1, the on-site air tightness detection system for the opening of a civil air defense project is characterized in that: It also includes an airbag that can be inflated and maintain pressure, and can occupy the space inside the opening of the civil air defense project after being inflated.

6. The on-site air tightness detection system for the opening of a civil air defense project according to any one of claims 1 to 5, characterized in that: The number of the reserved pipes is multiple and they are centrally arranged on the wall of the project opening.

7. A method for detecting air tightness of the opening of a civil air defense project on site, characterized in that: The invention comprises providing a system for detecting air tightness of the opening of a civil air defense project on site as claimed in any one of claims 1 to 6; using a smoke generating device to generate smoke in the opening of the civil air defense project; connecting an air pumping device to a reserved pipe through a pipeline to pump air into the opening of the civil air defense project, and stopping the air pumping when the air pressure value measured by the air pressure measuring device reaches a first preset value; within a specified time, if the measured air pressure value decreases by more than a specified value, the air tightness of the opening of the civil air defense project is determined to be unqualified, and if the measured air pressure value decreases by no more than a specified value, the air tightness of the opening of the civil air defense project is determined to be qualified; Find the location where the seal fails based on the leakage point.

8. The method for detecting air tightness of the opening of a civil air defense project on site according to claim 7 is characterized in that: A resistance wire and a thermal imaging device are also provided; the resistance wire is arranged in a gap where air leakage may occur or at the mouth of the gap; the thermal imaging device is used to find the hot air flow overflowing from the gap to determine the air leakage point.

9. The method for detecting air tightness of the opening of a civil air defense project on site according to claim 7, characterized in that: An airbag that can be inflated and maintained under pressure is also provided; before the detection begins and the protective door is not closed, the airbag is inflated and the pressure is maintained in the opening of the civil air defense project, or after the detection begins and the protective door is closed, the airbag is inflated and the pressure is maintained through a pipeline and the reserved tube.

10. The method for detecting air tightness of the opening of a civil air defense project on site according to claim 7, characterized in that: A pulse gas tank is also provided; when it is determined that the air tightness of the opening of the civil air defense project is unqualified, the air pump device is started to continue inflating so that the air pressure at the opening of the civil air defense project reaches a second preset value, and the second preset value is greater than the first preset value; the pulse gas tank is started to intermittently exhaust air in the opening of the civil air defense project, and the leakage point is found at the same time.

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