Gas tightness detection system for gas equipment

Abstract

The present invention discloses an air tightness detection system for gas equipment, which includes a positioning unit, a leak detector, a detection circuit and an assembly line. The gas equipment is located on the assembly line and moves on the assembly line. The positioning unit is fixed on the assembly line for positioning the gas equipment. The detection circuit and the leak detector are connected for automatically detecting the air tightness of the first valve, the second valve and the pipeline between the gas equipment. When the present invention is used, the gas equipment to be detected is placed on the assembly line. When the gas equipment flows to the detection station of the detection system along the assembly line, the gas equipment is positioned by the positioning unit, and then the detection circuit and the leak detector automatically work to complete the air tightness detection; the whole process does not require manual operation, and the automation of air tightness detection is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of air tightness detection, and in particular relates to an air tightness detection system for gas equipment. Background Art

[0002] For household gas stoves and similar gas products, for safety reasons, there must be no less than two independent closable valves connected in series to protect the product from leakage and other safety accidents; all valves must be fully inspected during the production process.

[0003] In the implementation of the test, a combination of manual and leak detectors is currently used. This method has two disadvantages: first, the test results are affected by the accuracy of the operator's reading of the instrument data, which may lead to misjudgment of whether the airtightness is qualified or not; second, the test requires manual operation, which consumes human resources. Summary of the invention

[0004] In view of this, the present invention provides an air tightness detection system for gas equipment, which realizes full automation of air tightness detection by applying a detection circuit in the air tightness detection system.

[0005] The technical solution adopted by the present invention is:

[0006] A gas tightness detection system for gas equipment comprises a positioning unit, a leak detector, a detection circuit and an assembly line. The gas equipment is located on the assembly line and moves on the assembly line. The positioning unit is fixed on the assembly line for positioning the gas equipment. The detection circuit and the leak detector are connected for automatically detecting the gas tightness of a first valve, a second valve and a pipeline therebetween of the gas equipment.

[0007] Preferably, the detection circuit includes a system startup module, a leak detector startup module, a leak detection module, a counting module, a leak detector reset module and a system reset module;

[0008] After the system startup module controls the start-up of the air tightness detection system, the positioning unit locates the gas equipment, the leak detector startup module works, and the air tightness of the first valve and the pipeline between the first valve and the second valve is detected by the leak detection module. After the detection is completed, the counting module counts the number of air tightness detections and is reset by the leak detector reset module; then, the air tightness of the second valve is detected by the leak detection module. After the detection is completed, the counting module again counts the number of air tightness detections, and finally the detection circuit is returned to the initial state by the system reset module.

[0009] Preferably, the positioning unit comprises a horizontal positioning module and a vertical positioning module, and the horizontal positioning module and the vertical positioning module are respectively arranged in the horizontal direction and the vertical direction of the assembly line to achieve horizontal positioning and vertical positioning.

[0010] Preferably, the system start-up module comprises a photoelectric switch SQ, the photoelectric switch SQ is connected to a first relay J1, and a normally closed contact J11 of the first relay J1 is connected to a horizontal positioning module.

[0011] Preferably, the horizontal positioning module includes a blocking cylinder, a first reversing solenoid valve V1 and a first sensing element K1. The input end of the blocking cylinder is connected to the normally closed contact J11 of the first relay J1, and the output end is connected to the blocking cylinder. After the piston rod of the blocking cylinder is extended, it contacts the first sensing element K1.

[0012] Preferably, the vertical positioning module comprises a positioning cylinder and a second electromagnetic reversing valve V2. When the second electromagnetic reversing valve V2 is energized, the piston rod of the positioning cylinder extends to block the gas equipment, so that it is positioned in a direction perpendicular to the direction of the assembly line.

[0013] Preferably, the leak detector starting module includes a second sensing element K2, which is connected to the leak detector; when the piston rod of the positioning cylinder extends to the middle of the stroke, the second sensing element K2 is instantaneously turned on, thereby controlling the start of the leak detector.

[0014] Preferably, the leak detection module comprises a third sensing element K3, the third sensing element K3 is connected to the input end of the third electromagnetic reversing valve V3, the output end of the third electromagnetic reversing valve V3 is connected to the pressing cylinder, and the pressing cylinder is used to press down the first valve.

[0015] Preferably, the counting module comprises a second relay J2, and a first make contact J21 of the second relay J2 is connected to the counting relay JDM.

[0016] Preferably, the leak detector reset module includes a third relay J3, the third relay J3 is connected to the second normally closed contact J22 of the second relay J2, the third relay J3 includes a first normally closed contact J31 and a second normally closed contact J32, the second normally closed contact J32 of the third relay J3 is connected to the fourth electromagnetic reversing valve V4, the fourth electromagnetic reversing valve V4 is connected to the rotating cylinder, the rotating cylinder is connected to the second valve and the fourth sensing element K4, the third normally closed contact J33 of the third relay J3 is connected to the second time relay JT2, and the delayed normally open contact JT21 of the second time relay JT2 is used to control the states of the first electromagnetic reversing valve V1, the second electromagnetic reversing valve V2, the third electromagnetic reversing valve V3 and the fourth electromagnetic reversing valve V4.

[0017] Preferably, the preset number of times set in the counting relay JMD is 2.

[0018] Preferably, the system reset module includes a fourth relay J4, which is connected to the normally closed output terminal JMD1 of the counting relay JMD, and the fourth relay J4 includes a normally open contact J41 and a normally closed contact J42 with a self-locking function; the system reset module further includes a fifth relay J5, which is connected to the contact JDM2 of the counting relay JMD.

[0019] Preferably, the assembly line includes a tooling plate and a tooling plate cylinder disposed on the tooling plate, and the tooling plate cylinder is connected to the movable open contact J41 of the fourth relay J4.

[0020] Preferably, the "NG" signal output terminal of the leak detector is connected to a buzzer.

[0021] Compared with the prior art, when the present invention is used, the gas equipment to be tested is placed on the assembly line. When the gas equipment flows along the assembly line to the testing station of the testing system, the gas equipment is positioned by the positioning unit, and then the detection circuit and the leak detector automatically work to complete the air tightness test. The entire process does not require manual operation, thus realizing the automation of air tightness testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a system block diagram of a gas tightness detection system for gas equipment provided by an embodiment of the present invention;

[0023] Figure 2a-2d is a circuit diagram of a detection circuit in a gas tightness detection system for gas equipment provided by an embodiment of the present invention;

[0024] Figure 3 It is a connection diagram of a valve to be tested in a gas tightness testing system for gas equipment provided by an embodiment of the present invention.

[0025] in:

[0026] 1. Positioning unit, 2. Leak detector, 3. Detection circuit, 4. First valve, 5. Second valve, 6. Tooling plate cylinder, 7. Buzzer, 11. Horizontal positioning module, 12. Vertical positioning module, 31. System start module, 32. Leak detector start module, 33. Leak detection module, 34. Counting module, 35. Leak detector reset module, 36. System reset module, 111. Blocking cylinder, 121. Positioning cylinder, 331. Pressing cylinder, 351. Rotating cylinder. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In the description of the present invention, it should be clarified that terms such as "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "up", "down", and "horizontal" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are merely for the convenience of describing the present invention. They do not mean that the devices or elements referred to must have a specific direction or position, and therefore cannot be understood as limitations on the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 in the present invention can be understood according to specific circumstances.

[0030] The embodiment of the present invention provides a gas tightness detection system for gas equipment, such as Figure 1 As shown, it includes a positioning unit 1, a leak detector 2, a detection circuit 3 and an assembly line, the gas equipment is located on the assembly line and moves on the assembly line, the positioning unit 1 is fixed on the assembly line for positioning the gas equipment, and the detection circuit 3 and the leak detector 2 are connected to automatically detect the air tightness of the first valve 4, the second valve 5 of the gas equipment and the pipeline therebetween;

[0031] In this way, using the above structure, the gas equipment to be tested is placed on the assembly line. When the gas equipment flows along the assembly line to the detection station of the detection system, the gas equipment is positioned by the positioning unit 1, and then the detection circuit 3 and the leak detector 2 automatically work to complete the air tightness detection.

[0032] The detection circuit 3 includes a system startup module 31, a leak detector startup module 32, a leak detection module 33, a counting module 34, a leak detector reset module 35 and a system reset module 36;

[0033] Thus, the specific working process of the detection circuit 3 is as follows: Figure 1As shown by the arrow in , after the system startup module 31 controls the air tightness detection system to start, the positioning unit 1 locates the gas equipment, the leak detector startup module 32 works, and the air tightness of the first valve 4 and the pipeline between the first valve 4 and the second valve 5 is detected by the leak detection module 33. After the detection is completed, the counting module 34 counts the number of air tightness detections and is reset by the leak detector reset module 35; then, the air tightness of the second valve 5 is detected by the leak detection module 33. After the detection is completed, the counting module 34 counts the number of air tightness detections again, and finally the detection circuit 3 is returned to the initial state by the system reset module 36.

[0034] The positioning unit 1 includes a horizontal positioning module 11 and a vertical positioning module 12, and the horizontal positioning module 11 and the vertical positioning module 12 are respectively arranged in the horizontal direction and the vertical direction of the assembly line to achieve horizontal positioning and vertical positioning;

[0035] In this way, the horizontal positioning module 11 prevents the gas equipment to be tested from missing the air tightness test as the pipeline continues to flow; the vertical positioning module 12 ensures the accurate position of the gas equipment to be tested in the direction perpendicular to the pipeline.

[0036] The system start module 31 includes a photoelectric switch SQ, the photoelectric switch SQ is connected to a first relay J1, and a normally closed contact J11 of the first relay J1 is connected to a horizontal positioning module 11;

[0037] In this way, when the gas equipment to be inspected flows into the inspection station along the production line from the previous process, the photoelectric switch SQ is turned on under the light shielding of the gas equipment, and the airtightness detection system is started.

[0038] like Figure 2a-2d As shown, the horizontal positioning module 11 includes a blocking cylinder 111, a first reversing solenoid valve V1 and a first sensing element K1. The input end of the blocking cylinder 111 is connected to the normally closed contact J11 of the first relay J1, and the output end is connected to the blocking cylinder 111. After the piston rod of the blocking cylinder 111 is extended, it contacts the first sensing element K1.

[0039] In this way, after the normally closed contact J11 of the first relay J1 is closed, the first electromagnetic reversing valve V1 is energized, and the piston rod of the blocking cylinder 111 extends to block the gas equipment, so that the gas equipment is positioned in the direction of the assembly line.

[0040] The vertical positioning module 12 includes a positioning cylinder 121 and a second electromagnetic reversing valve V2. When the second electromagnetic reversing valve V2 is energized, the piston rod of the positioning cylinder 121 extends to block the gas equipment, so that it is positioned in a direction perpendicular to the direction of the assembly line;

[0041] Thus, when the piston rod of the blocking cylinder 111 extends, the first sensing element K1 is turned on, the second electromagnetic reversing valve V2 is energized, and the piston rod of the positioning cylinder 121 extends to block the cooker, so that the cooker is positioned in a direction perpendicular to the logistics direction.

[0042] The leak detector start module 32 includes a second sensing element K2, and the second sensing element K2 is connected to the leak detector 2;

[0043] In this way, when the piston rod of the positioning cylinder 121 extends to the middle of the stroke, the second sensing element K2 is instantly turned on, thereby controlling the leak detector 2 to start.

[0044] The leakage detection module 33 includes a third sensing element K3 , which is connected to the input end of the third electromagnetic reversing valve V3 , and the output end of the third electromagnetic reversing valve V3 is connected to the pressing cylinder 331 , which is used to press down the first valve 4 .

[0045] The counting module 34 includes a second relay J2 , and a first make contact J21 of the second relay J2 is connected to the counting relay JDM.

[0046] The leak detector reset module 35 includes a third relay J3, and the third relay J3 is connected to the second normally closed contact J22 of the second relay J2. The third relay J3 includes a first normally closed contact J31 and a second normally closed contact J32. The second normally closed contact J32 of the third relay J3 is connected to the fourth electromagnetic reversing valve V4, and the fourth electromagnetic reversing valve V4 is connected to the rotating cylinder 351, and the rotating cylinder 351 is connected to the second valve 5 and the fourth sensing element K4. The third normally closed contact J33 of the third relay J3 is connected to the second time relay JT2, and the delayed normally open contact JT21 of the second time relay JT2 is used to control the states of the first electromagnetic reversing valve V1, the second electromagnetic reversing valve V2, the third electromagnetic reversing valve V3 and the fourth electromagnetic reversing valve V4.

[0047] The number of times set in the counting relay JMD is preset to 2.

[0048] The system reset module 36 includes a fourth relay J4, which is connected to the normally closed output terminal JMD1 of the counting relay JMD, and the fourth relay J4 includes a normally open contact J41 and a normally closed contact J42 with a self-locking function; the system reset module 36 further includes a fifth relay J5, which is connected to the contact JDM2 of the counting relay JMD.

[0049] The assembly line includes a tooling plate and a tooling plate cylinder 6 arranged on the tooling plate, and the tooling plate cylinder 6 is connected to the movable open contact J41 of the fourth relay J4.

[0050] In order to avoid the situation that the airtightness has problems but the staff has not discovered them, the "NG" signal output terminal of the leak detector 2 is connected to the buzzer 7; thus, the staff is reminded by the alarm sound of the buzzer with high reliability.

[0051] The gas device in this embodiment is a stove, and can also be any other gas device with two valve structures, where Figure 3 As shown, the first valve 4 and the second valve 5 are in series relationship.

[0052] In addition, if Figure 2b and 2c As shown, terminal port 2 and terminal port 10 of the leak detector 2 are a pair of terminals for inputting a start command, and terminal port 1 and terminal port 9 are a pair of terminals for inputting a normally-on reset signal.

[0053] The specific detection process of the gas tightness detection system for gas equipment provided in this embodiment is as follows:

[0054] S1, starting the detection circuit 3 through the system starting module 31, specifically:

[0055] When the gas equipment flows into the inspection station along the assembly line from the previous process, the photoelectric switch SQ is turned on under the light shielding of the gas equipment, and then the normally closed contact J11 of the first relay J1 is closed;

[0056] S2, positioning the gas equipment through the positioning unit 1, specifically:

[0057] After the normally made contact J11 of the first relay J1 is closed, the first electromagnetic reversing valve V1 is energized, and the piston rod of the blocking cylinder 111 extends to block the gas equipment, so that the gas equipment is positioned in the direction of the assembly line; at the same time, the normally broken contact J12 of the first relay J1 is disconnected, and the counting relay JDM is released from the reset state;

[0058] When the piston rod of the blocking cylinder 111 extends, the first sensing element K1 is turned on, the second electromagnetic reversing valve V2 is energized, and the piston rod of the positioning cylinder 121 extends to block the cooker, so that the cooker is positioned in a direction perpendicular to the logistics direction;

[0059] S3, starting the leak detector 2 through the leak detector starting module 32, specifically:

[0060] When the piston rod of the positioning cylinder 121 extends to the middle of the stroke, the second sensing element K2 is instantaneously turned on, and the "START" switch of the leak detector 2 is activated, and the leak detector 2 enters the air tightness detection;

[0061] S4, performing air tightness detection on the first valve 4 and the pipeline between the first valve 4 and the second valve 5 through the leak detection module 33, specifically:

[0062] As the piston rod of the positioning cylinder 121 continues to extend, the third sensing element K3 is turned on, the third electromagnetic reversing valve V3 is energized, the piston rod of the pressing cylinder 331 extends and presses down the valve stem of the plug valve, and the first valve 4 is opened. At this time, the leak detector 2 performs air tightness detection on the first valve 4 and the pipeline between the first valve 4 and the second valve 5. When the gas leakage is detected to be within the specified range, the leak detector 2 outputs an "OK" signal, and the thirteenth port and the seventeenth port of the leak detector 2 are turned on.

[0063] S5, counting the air tightness detection through the counting module, specifically:

[0064] When the thirteenth and seventeenth ports of the leak detector 2 are connected, the second relay J2 is energized, and the first make contact J21 of the second relay J2 is closed to output a pulse signal to the counting relay JDM, and the counting relay JDM counts 1, completing the first air tightness detection;

[0065] S6, completing the reset through the leak detector reset module 35, specifically:

[0066] After the first air tightness test is completed, the normally closed contact J22 of the second relay J2 is closed, the third relay J3 is energized so that it forms a self-locking state under the action of the first normally closed contact J31, the second normally closed contact J32 of the third relay J3 is closed, the fourth electromagnetic reversing valve V4 is energized, the rotary cylinder 351 rotates to drive the plug of the second valve 5 to rotate, the second valve 5 is opened, the fourth sensing element K4 disconnects the circuit, the leak detector 2 is in a reset state, the "OK" electrical signal of the leak detector 2 disappears, and the second relay J2 is de-energized;

[0067] Since the third relay J3 is energized, its third make contact J33 is closed, the second time relay JT2 is energized, and the delayed open contact JT21 of the second time relay JT2 is delayed disconnected, so that the first electromagnetic reversing valve V1, the second electromagnetic reversing valve V2, the third electromagnetic reversing valve V3 and the fourth electromagnetic reversing valve V4 are de-energized, so that the pistons of the blocking cylinder 111, the positioning cylinder 121, the pressing cylinder 331 and the rotating cylinder 351 are all reset; the resetting of the rotating cylinder 351 makes the fourth sensing element K4 conductive, and the conduction of the fourth sensing element K4 makes the reset port of the leak detector 2 conductive, and the leak detector 2 resumes the standby state;

[0068] S7, performing air tightness detection on the second valve 5 through the leak detection module 33, specifically:

[0069] The pressing cylinder 331 is reset, the valve stem of the plug valve is reset, and the first valve 4 is closed (i.e., not conducting); the positioning cylinder 121 is reset, and when its piston is reset to the middle of the stroke, the second sensing element K2 is instantly turned on, and the "START" switch of the leak detector 2 is started, and the leak detector begins to perform air tightness detection on the second valve 5; when the leakage of the detected gas is within the specified value, the "OK" signal of the leak detector turns on the output port, and the first moving contact J21 of the second relay J2 is closed to output a pulse signal to the counting device JDM, and JDM counts 2;

[0070] S8, the detection circuit 3 is returned to the initial state through the system reset module 36, specifically:

[0071] Since the output count of the counter electrical device JDM is preset to 2, when the first normally closed contact J21 of the second relay J2 is closed for the second time, the counter electrical device JDM receives the second signal input and generates a pulse output, the normally closed output terminal JDM1 is closed, the fourth relay J4 is energized, the fourth relay J4 is energized and forms a self-locking under the action of the normally closed contact J42, the normally open contact J41 of the fourth relay J4 is disconnected, the third relay J3 loses power and resets, and the self-locking of the third relay J3 is released, the third normally closed contact J33 of the third relay J3 is disconnected, and the second time relay JT2 is reset;

[0072] The counter electrical appliance JDM receives the second signal input and generates a pulse output, the break terminal JDM2 is disconnected, the fifth relay J5 loses power, the close terminal J51 of the fifth relay J5 is disconnected, and the leakage detector 2 is reset;

[0073] Afterwards, the fourth relay J4 is energized, and the make contact J43 of the fourth relay J4 is closed to make the tooling plate cylinder 6 move downward, the blocking of the tooling plate is released, and the gas equipment flows out of the test station along with the tooling;

[0074] Afterwards, when the fourth relay J4 is energized, the first time relay JT1 is energized and remains energized while the fourth relay J4 maintains self-locking. The delay time of the first time relay JT1 is adjusted so that the cooker completely flows out of the test station and the photoelectric switch SQ is not blocked by the cooker, the delayed break contact JT11 of the first time relay JT1 is disconnected, the fourth relay J4 is de-energized and reset, the self-locking is released, and the break contact J41 of the fourth relay J4 is closed; the photoelectric switch SQ is not blocked by the cooker and is in a standby state, the first relay J1 is de-energized, its break contact J12 is closed, and the counter JDM is in a reset state; at this point, the control circuit 3 is restored to its initial state.

[0075] In addition, when detecting the air tightness of the first valve 4 or the second valve 5, if the gas leakage exceeds the set value, the leak detector outputs an "NG" signal to connect the seventeenth port and the fourteenth port of the leak detector, and the buzzer 7 sounds an alarm; when the alarm sound is heard, the double reset button can be manually pressed and the gas equipment can be removed for inspection.

[0076] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A gas tightness detection system for gas equipment, characterized in that: It comprises a positioning unit (1), a leak detector (2), a detection circuit (3) and an assembly line, wherein the gas equipment is located on the assembly line and moves on the assembly line, the positioning unit (1) is fixed on the assembly line for positioning the gas equipment, and the detection circuit (3) and the leak detector (2) are connected for automatically detecting the air tightness of a first valve (4), a second valve (5) and a pipeline therebetween of the gas equipment; The detection circuit (3) comprises a system start-up module (31), a leak detector start-up module (32), a leak detection module (33), a counting module (34), a leak detector reset module (35) and a system reset module (36); After the system start-up module (31) controls the start-up of the air tightness detection system, the positioning unit (1) locates the gas equipment, the leak detector start-up module (32) works, and the air tightness of the first valve (4) and the pipeline between the first valve (4) and the second valve (5) is detected by the leak detection module (33). After the detection is completed, the counting module (34) counts the number of air tightness detections and resets the system by the leak detector reset module (35). Then, the air tightness of the second valve (5) is detected by the leak detection module (33). After the detection is completed, the counting module (34) counts the number of air tightness detections again, and finally the detection circuit (3) is returned to the initial state by the system reset module (36); The positioning unit (1) comprises a horizontal positioning module (11) and a vertical positioning module (12), wherein the horizontal positioning module (11) and the vertical positioning module (12) are respectively arranged in the horizontal direction and the vertical direction of the assembly line to achieve horizontal positioning and vertical positioning; The system start module (31) comprises a photoelectric switch SQ, the photoelectric switch SQ is connected to a first relay J1, and a normally closed contact J11 of the first relay J1 is connected to a horizontal positioning module (11); The horizontal positioning module (11) comprises a blocking cylinder (111), a first electromagnetic reversing valve V1 and a first sensing element K1; the input end of the first electromagnetic reversing valve V1 is connected to a normally closed contact J11 of a first relay J1, and the output end is connected to the blocking cylinder (111); after the piston rod of the blocking cylinder (111) is extended, it contacts the first sensing element K1; The vertical positioning module (12) comprises a positioning cylinder (121) and a second electromagnetic reversing valve V2. When the second electromagnetic reversing valve V2 is energized, the piston rod of the positioning cylinder (121) extends to block the gas equipment, so that the gas equipment is positioned in a direction perpendicular to the flow line direction. The leak detector starting module (32) comprises a second sensing element K2, and the second sensing element K2 is connected to the leak detector (2); When the piston rod of the positioning cylinder (121) extends to the middle of the stroke, the second sensing element K2 is instantly turned on, thereby controlling the leak detector (2) to start; The leak detection module (33) comprises a third sensing element K3, the third sensing element K3 is connected to the input end of a third electromagnetic reversing valve V3, the output end of the third electromagnetic reversing valve V3 is connected to a pressing cylinder (331), and the pressing cylinder (331) is used to press down the first valve (4).

2. The gas tightness detection system for gas equipment according to claim 1, characterized in that: The counting module (34) comprises a second relay J2, wherein a first make contact J21 of the second relay J2 is connected to the counting relay JDM.

3. The air tightness detection system for gas equipment according to claim 2, characterized in that: The leak detector reset module (35) comprises a third relay J3, the third relay J3 is connected to the second normally closed contact J22 of the second relay J2, the third relay J3 comprises a first normally closed contact J31 and a second normally closed contact J32, the second normally closed contact J32 of the third relay J3 is connected to the fourth electromagnetic reversing valve V4, the fourth electromagnetic reversing valve V4 is connected to the rotary cylinder (351), the rotary cylinder (351) is connected to the second valve (5) and the fourth induction element K4, the third normally closed contact J33 of the third relay J3 is connected to the second time relay JT2, the delayed normally open contact JT21 of the second time relay JT2 is used to control the states of the first electromagnetic reversing valve V1, the second electromagnetic reversing valve V2, the third electromagnetic reversing valve V3 and the fourth electromagnetic reversing valve V4.

4. The gas tightness detection system for gas equipment according to claim 2 or 3, characterized in that: The preset number of times set in the counting relay JDM is 2.

5. The air tightness detection system for gas equipment according to claim 4, characterized in that: The system reset module (36) comprises a fourth relay J4, the fourth relay J4 being connected to a normally closed output terminal JDM1 of a counting relay JDM, the fourth relay J4 comprising a normally open contact J41 and a normally closed contact J42 having a self-locking function; the system reset module (36) further comprises a fifth relay J5, the fifth relay J5 being connected to a contact JDM2 of the counting relay JDM.

6. The air tightness detection system for gas equipment according to claim 5, characterized in that: The assembly line comprises a tooling plate and a tooling plate cylinder (6) arranged on the tooling plate, wherein the tooling plate cylinder (6) is connected to a movable open contact J41 of a fourth relay J4.

7. The air tightness detection system for gas equipment according to any one of claims 1 to 3, characterized in that: The "NG" signal output terminal of the leak detector (2) is connected to a buzzer (7).

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