A dynamic mechanism sealing test device and a test method

Abstract

The present invention provides a power mechanism sealing test device and a test method, comprising: a first branch is provided with a start button, a pressure upper limit relay contact, and a pneumatic valve relay coil, a ninth branch is provided with a pneumatic valve relay contact and a pneumatic solenoid valve, one end of the second branch is connected to the first branch, two ends of the third branch are connected to the first branch and the second branch, the third branch is provided with a pneumatic valve relay contact, the fourth branch is provided with a pressure upper limit relay contact and a pressure upper limit relay coil, the fifth branch is provided with a pneumatic valve relay contact, a pressure gauge, and a pressure lower limit relay coil, the sixth branch is provided with a pressure upper limit relay contact and a pressure maintaining relay coil, the seventh branch is provided with a pressure maintaining relay contact, a pressure lower limit relay contact, and an alarm mechanism, the two ends of the eighth branch are connected one-to-one with the seventh branch and the second power line, and the eighth branch is provided with a pressure lower limit relay contact and an alarm mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of sealing performance testing, and in particular to a power mechanism sealing testing device and a testing method. Background Art

[0002] Before installing and testing the transmission and drive axle on a vehicle, they must first be inspected for leaks. Traditionally, after assembly, manual testing with a standard leak test tank is used to observe the transmission for leaks. This method relies primarily on manual pressure application, which cannot be controlled in terms of pressure intensity or duration. This can be particularly prone to fatigue during extended testing periods, leading to potential leaks not being discovered promptly and affecting the accuracy of leak detection. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a power mechanism sealing test device and a test method in view of the deficiencies in the prior art.

[0004] The technical solution of the present invention for solving the above technical problems is as follows: A power mechanism sealing test device, comprising: a first power line, a second power line, a first branch, a second branch, a third branch, a fourth branch, a fifth branch, a sixth branch, a seventh branch, an eighth branch, and a ninth branch, wherein the first branch and the ninth branch are connected in parallel between the first power line and the second power line, the first branch is provided with a start button, a pressure upper limit relay contact, and a pneumatic valve relay coil, the ninth branch is provided with a pneumatic valve relay contact and a pneumatic solenoid valve, one end of the second branch is connected to the first branch, the two ends of the third branch are connected to the first branch and the second branch in a one-to-one correspondence, the third branch is provided with a pneumatic valve relay contact, and the pneumatic valve relay contact on the third branch is connected to the first branch. The start buttons on the road are connected in parallel, the fourth branch, the fifth branch, and the sixth branch are connected in parallel between the second branch and the second power line, the fourth branch is provided with an upper pressure limit relay contact and an upper pressure limit relay coil, the fifth branch is provided with a pneumatic valve relay contact, a pressure gauge and a lower pressure limit relay coil, the first end of the pressure gauge is connected to the fourth branch, the sixth branch is provided with an upper pressure limit relay contact and a pressure maintaining relay coil, the seventh branch is provided with a pressure maintaining relay contact, a lower pressure limit relay contact and a first alarm mechanism for indicating unqualified information, the two ends of the eighth branch are connected to the seventh branch and the second power line one by one, and the eighth branch is provided with a lower pressure limit relay contact and a second alarm mechanism for indicating qualified.

[0005] The beneficial effects of the technical solution of the present invention include: solving the problems of unstable leak test pressure, inconsistent leak test duration, and inaccurate leak test information transmission. A pressure gauge is used to control the upper and lower pressure limits, and an alarm mechanism is used to distinguish between qualified and unqualified products. This ensures a sufficient leak test pressure holding time, facilitates pressure adjustment, facilitates observation of specific leak points, and automatically identifies faulty transmissions and drive axles, preventing batch oil leaks. The pressure and duration can be easily controlled, reducing user labor intensity, improving automation, increasing accuracy, and enhancing work efficiency.

[0006] Furthermore, the pneumatic valve relay contacts include: a first contact, a second contact and a third contact, the first contact is located on the third branch, the first contact is connected in parallel with the start button, the second contact is located on the fifth branch, and the third contact is located on the ninth branch.

[0007] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0008] Furthermore, the pressure upper limit relay contacts include: a fourth contact, a fifth contact, and a sixth contact, the fourth contact is located on the first branch, the fifth contact is located on the fourth branch, and the sixth contact is located on the sixth branch.

[0009] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0010] Furthermore, the lower pressure limit relay contacts include: a seventh contact and an eighth contact, the seventh contact is located on the seventh branch, and the eighth contact is located on the eighth branch.

[0011] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0012] Furthermore, a stop button is provided on the first branch, one end of the stop button is connected to the first power line, and the other end of the stop button is connected to the start button.

[0013] The beneficial effect of adopting the above further technical solution is that the stop button can be used to quickly stop the operation after a gas leak occurs.

[0014] Furthermore, the first alarm mechanism and the second alarm mechanism are both alarm lights.

[0015] The beneficial effect of adopting the above further technical solution is that the alarm light is used to automatically alarm when there is a leak in the gearbox or drive axle, and employees can observe the specific leak point.

[0016] Furthermore, the pressure gauge is an electric contact pressure gauge with a range of 0-0.1 MPa.

[0017] The beneficial effects of adopting the above further technical solution are: improving accuracy and facilitating the completion of sealing testing work.

[0018] Furthermore, the first power line and the second power line are connected to a 24V power supply.

[0019] The beneficial effects of adopting the above further technical solution are: facilitating the selection of power supply, and facilitating storage and transportation.

[0020] Furthermore, it also includes: a bracket and a pneumatic control system, the pneumatic control system is installed on the bracket, and the pneumatic control system is connected to the pneumatic solenoid valve.

[0021] The beneficial effect of adopting the above further technical solution is that it facilitates the completion of the sealing test work.

[0022] In addition, the present invention further provides a power mechanism sealing test method, based on any one of the power mechanism sealing test devices described above, the power mechanism sealing test method comprising:

[0023] S1. Click the start button, the pneumatic valve relay contacts close, the pneumatic solenoid valve opens, and compressed air is filled into the power mechanism;

[0024] S2. When the pressure inside the power mechanism reaches the upper limit pressure value of the pressure gauge, the upper limit pressure relay contacts are closed, the pneumatic valve relay contacts are disconnected, the pressure holding relay contacts are normally open, the timing starts, the pneumatic solenoid valve closes, and the compressed air supply to the power mechanism stops;

[0025] S3, when the timing is completed, the pressure-maintaining relay contacts are closed;

[0026] S4. If the pressure value of the pressure gauge is greater than the lower limit value, the contact of the lower limit pressure relay is disconnected, which is used to indicate that the qualified second alarm mechanism is working;

[0027] S5. If the pressure value of the pressure gauge is less than the lower limit value, the contact of the lower limit pressure relay is closed, and the first alarm mechanism for indicating unqualified information is activated;

[0028] S6. Remove the power mechanism and click the stop button to complete the test.

[0029] The beneficial effects of the technical solution of the present invention include: solving the problems of unstable leak test pressure, inconsistent leak test duration, and inaccurate leak test information transmission. A pressure gauge is used to control the upper and lower pressure limits, and an alarm mechanism is used to distinguish between qualified and unqualified products. This ensures a sufficient leak test pressure holding time, facilitates pressure adjustment, facilitates observation of specific leak points, and automatically identifies faulty transmissions and drive axles, preventing batch oil leaks. The pressure and duration can be easily controlled, reducing user labor intensity, improving automation, increasing accuracy, and enhancing work efficiency.

[0030] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a structural schematic diagram of a power mechanism sealing test device provided in an embodiment of the present invention.

[0032] Figure 2 A schematic flow chart of a power mechanism sealing test method provided in an embodiment of the present invention.

[0033] Explanation of the accompanying reference numerals: 1. First power cord; 2. Second power cord; 3. First branch; 4. Second branch; 5. Third branch; 6. Fourth branch; 7. Fifth branch; 8. Sixth branch; 9. Seventh branch; 10. Eighth branch; 11. Ninth branch; 12. Start button; 13. Upper pressure limit relay contact; 14. Pneumatic valve relay coil; 15. Pneumatic valve relay contact; 16. Pneumatic solenoid valve; 17. Upper pressure limit relay coil; 18. Pressure gauge; 19. Lower pressure limit relay coil; 20. Pressure holding relay coil; 21. Pressure holding relay contact; 22. Lower pressure limit relay contact; 23. First alarm mechanism; 24. Second alarm mechanism; 25. First contact; 26. Second contact; 27. Third contact; 28. Fourth contact; 29. Fifth contact; 30. Sixth contact; 31. Seventh contact; 32. Eighth contact; 34. Stop button. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] like Figure 1As shown, an embodiment of the present invention provides a power mechanism sealing test device, including: a first power line 1, a second power line 2, a first branch 3, a second branch 4, a third branch 5, a fourth branch 6, a fifth branch 7, a sixth branch 8, a seventh branch 9, an eighth branch 10, and a ninth branch 11. The first branch 3 and the ninth branch 11 are connected in parallel between the first power line 1 and the second power line 2. The first branch 3 is provided with a start button 12, a pressure upper limit relay contact 13, and a pneumatic valve relay coil 14. The ninth branch 11 is provided with a pneumatic valve relay contact 15 and a pneumatic solenoid valve 16. One end of the second branch 4 is connected to the first branch 3, and the two ends of the third branch 5 are connected to the first branch 3 and the second branch 4 in a one-to-one correspondence. The third branch 5 is provided with a pneumatic valve relay contact 15, and the pneumatic valve relay contact 15 on the third branch 5 is connected to the start button 12 on the first branch 3. The push button 12 is connected in parallel, the fourth branch 6, the fifth branch 7, and the sixth branch 8 are connected in parallel between the second branch 4 and the second power line 2, the fourth branch 6 is provided with a pressure upper limit relay contact 13 and a pressure upper limit relay coil 17, the fifth branch 7 is provided with a pneumatic valve relay contact 15, a pressure gauge 18 and a pressure lower limit relay coil 19, the first end of the pressure gauge 18 is connected to the fourth branch 6, the sixth branch 8 is provided with a pressure upper limit relay contact 13 and a pressure maintaining relay coil 20, the seventh branch 9 is provided with a pressure maintaining relay contact 21, a pressure lower limit relay contact 22 and a first alarm mechanism 23 for indicating unqualified information, the two ends of the eighth branch 10 are connected to the seventh branch 9 and the second power line 2 one by one, and the eighth branch 10 is provided with a pressure lower limit relay contact 22 and a second alarm mechanism 24 for indicating qualified.

[0036] The beneficial effects of the technical solution of the present invention include: solving the problems of unstable leak test pressure, inconsistent leak test duration, and inaccurate leak test information transmission. A pressure gauge is used to control the upper and lower pressure limits, and an alarm mechanism is used to distinguish between qualified and unqualified products. This ensures a sufficient leak test pressure holding time, facilitates pressure adjustment, facilitates observation of specific leak points, and automatically identifies faulty transmissions and drive axles, preventing batch oil leaks. The pressure and duration can be easily controlled, reducing user labor intensity, improving automation, increasing accuracy, and enhancing work efficiency.

[0037] Among them, the power mechanism can be a drive axle or a gearbox.

[0038] Compressed air is injected into the workpiece (drive axle, gearbox) to reach the set upper pressure limit and then sealed. If the workpiece pressure value is higher than the set lower limit within the specified time, the seal is judged to be qualified. If it is lower than the set lower limit, the seal is judged to be unqualified.

[0039] In the diagram, L and M are the two power lines for the DC power supply output. SB1 is the stop button, which quickly stops the test if a leak occurs. SB2 is the start button, which controls the on / off switching of the pneumatic solenoid valve. KA1, KA2, and KA3 are relays (pneumatic valve relay, upper pressure limit relay, and lower pressure limit relay). YV is the pneumatic solenoid valve, which controls the on / off switching of compressed air. KT is the pressure-maintaining relay, which controls the pressure during the leak test, maintaining a constant 0.025-0.035 MPa. HL1 is the alarm light, which automatically sounds an alarm when a leak is detected in the transmission or drive axle, allowing the user to identify the leak. This system features high performance, high sensitivity, and ease of use.

[0040] This eliminates the problem of batch oil leakage. The overall layout is compact, highly flexible, and can be flexibly moved. The integrated control system features a simple design and easy-to-understand operation, reducing operator observation time and reducing the risk of oil flowing to customers due to undetectable leaks.

[0041] like Figure 1 As shown, further, the pneumatic valve relay contact 15 includes: a first contact 25, a second contact 26 and a third contact 27, the first contact 25 is located on the third branch 5, the first contact 25 is connected in parallel with the start button 12, the second contact 26 is located on the fifth branch 7, and the third contact 27 is located on the ninth branch 11.

[0042] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0043] like Figure 1 As shown, further, the pressure upper limit relay contact 13 includes: a fourth contact 28, a fifth contact 29, and a sixth contact 30, the fourth contact 28 is located on the first branch 3, the fifth contact 29 is located on the fourth branch 6, and the sixth contact 30 is located on the sixth branch 8.

[0044] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0045] like Figure 1 As shown, further, the lower pressure limit relay contact 22 includes: a seventh contact 31 and an eighth contact 32 , the seventh contact 31 is located on the seventh branch 9 , and the eighth contact 32 is located on the eighth branch 10 .

[0046] The beneficial effects of adopting the above-mentioned further technical solution are: simplifying the structure, facilitating installation and maintenance, and facilitating completion of sealing testing work.

[0047] like Figure 1As shown, further, a stop button 34 is provided on the first branch 3 , one end of the stop button 34 is connected to the first power line 1 , and the other end of the stop button 34 is connected to the start button 12 .

[0048] The beneficial effect of adopting the above further technical solution is that the stop button can be used to quickly stop the operation after a gas leak occurs.

[0049] like Figure 1 As shown, further, the first alarm mechanism 23 and the second alarm mechanism 24 are both alarm lights.

[0050] The beneficial effect of adopting the above further technical solution is that the alarm light is used to automatically alarm when there is a leak in the gearbox or drive axle, and employees can observe the specific leak point.

[0051] Furthermore, the pressure gauge 18 is an electric contact pressure gauge with a range of 0-0.1 MPa.

[0052] The beneficial effects of adopting the above further technical solution are: improving accuracy and facilitating the completion of sealing testing work.

[0053] like Figure 1 As shown, further, the first power line 1 and the second power line 2 are connected to a 24V power supply.

[0054] The beneficial effects of adopting the above further technical solution are: facilitating the selection of power supply, and facilitating storage and transportation.

[0055] Furthermore, it also includes: a bracket and a pneumatic control system, the pneumatic control system is installed on the bracket, and the pneumatic control system is connected to the pneumatic solenoid valve.

[0056] The beneficial effect of adopting the above further technical solution is that it facilitates the completion of the sealing test work.

[0057] The power mechanism sealing test device provided by the present invention is suitable for all assembled drive axles and gearboxes, and solves the problems of unstable leak test pressure, inconsistent leak test time, and inaccurate leak test information transmission. The system (power mechanism sealing test device) adopts a time relay to control the leak test pressure holding time, adopts an electric contact pressure gauge (pressure gauge) to control the high and low limits of pressure, and adopts alarm lights (first alarm mechanism and second alarm mechanism) to distinguish qualified products from unqualified products, meets the leak test pressure holding time, is easy to adjust the pressure, is easy to observe the specific leakage point, and automatically identifies faulty gearboxes and drive axles, thereby preventing the occurrence of batch oil leakage problems, improving customer satisfaction, and improving environmental protection levels.

[0058] The present invention provides a power mechanism sealing test device that can be used for gearbox and drive axle leak testing. The device can ensure the stability of pressure during the testing process, and will not cause fatigue or difficulty in judging leaks due to manual visual inspection during long-term work, so as to ensure that leak testing is carried out efficiently and accurately. It also includes: a bracket for supporting the pneumatic control system; different from the traditional solution of manual ordinary testing using a leak test pool, unstable pressure, and uncertain time, the power mechanism sealing test device provided by the present invention is an automatically controlled leak testing device, which uses a dedicated pneumatic control system, and at the same time uses a pneumatic solenoid valve, an electric contact pressure gauge, a timer, a pressure relay, and an alarm indicator light (a first alarm mechanism and a second alarm mechanism) to realize faulty products, so as to ensure that leak testing is carried out efficiently and accurately.

[0059] like Figure 2 As shown, in addition, the present invention further provides a power mechanism sealing test method, based on any one of the power mechanism sealing test devices described above, the power mechanism sealing test method includes:

[0060] S1. Click the start button, the pneumatic valve relay contacts close, the pneumatic solenoid valve opens, and compressed air is filled into the power mechanism;

[0061] S2. When the pressure inside the power mechanism reaches the upper limit pressure value of the pressure gauge, the upper limit pressure relay contacts are closed, the pneumatic valve relay contacts are disconnected, the pressure holding relay contacts are normally open, the timing starts, the pneumatic solenoid valve closes, and the compressed air supply to the power mechanism stops;

[0062] S3. When the timing is completed, the contacts of the pressure-maintaining relay are closed;

[0063] S4. If the pressure value of the pressure gauge is greater than the lower limit value, the contact of the lower limit pressure relay is disconnected, which is used to indicate that the qualified second alarm mechanism is working;

[0064] S5. If the pressure value of the pressure gauge is less than the lower limit value, the contact of the lower limit pressure relay is closed, and the first alarm mechanism for indicating unqualified information is activated;

[0065] S6. Remove the power mechanism and click the stop button to complete the test.

[0066] The beneficial effects of the technical solution of the present invention include: solving the problems of unstable leak test pressure, inconsistent leak test duration, and inaccurate leak test information transmission. A pressure gauge is used to control the upper and lower pressure limits, and an alarm mechanism is used to distinguish between qualified and unqualified products. This ensures a sufficient leak test pressure holding time, facilitates pressure adjustment, facilitates observation of specific leak points, and automatically identifies faulty transmissions and drive axles, preventing batch oil leaks. The pressure and duration can be easily controlled, reducing user labor intensity, improving automation, increasing accuracy, and enhancing work efficiency.

[0067] Specifically, (1): select an electric contact pressure gauge with a range of 0-0.1 MPa, and choose to purchase a 24V switching power supply, a 24V alarm light, and a timer (pressure-maintaining relay);

[0068] (2): After the air circuit is connected, click the start button SB2, the pneumatic valve relay KA1 is energized, the pneumatic solenoid valve YV is opened, and the system starts to fill the workpiece with compressed air;

[0069] (3) When the pressure value reaches the upper limit pressure value set by the electric contact pressure gauge, the pressure upper limit relay KA2 is energized, and at the same time the pneumatic valve relay KA1 is disconnected, and the time relay (pressure holding relay) KT starts timing. At this time, the pneumatic solenoid valve is closed, and the compressed air is stopped from being filled into the workpiece;

[0070] (4) When the time relay KT finishes timing, its normally open contact closes;

[0071] (5) If the pressure value of the electric contact pressure gauge is higher than the lower limit value, the pressure lower limit relay KA3 is disconnected, its normally closed contact is in the closed state, and the normally open contact is in the open state. At this time, the qualified (green) alarm light HL2 is on, and the seal is judged to be qualified; if the pressure value of the electric contact pressure gauge is lower than the lower limit value, the pressure lower limit relay KA3 is energized, its normally open contact is in the closed state, and the normally closed contact is in the open state. At this time, the unqualified (red) alarm light HL1 is on, and the seal is judged to be unqualified;

[0072] (6) After the leak test is completed, remove the workpiece and click the stop button SB1 to complete the test process;

[0073] (7) To measure the next workpiece, repeat steps 1-5 above.

[0074] The original leak test mode was cancelled, work efficiency was improved, and the process was gradually transformed towards automation to simultaneously meet the leak test needs of various component assemblies.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power mechanism sealing test device, characterized in that: include: The first power line, the second power line, the first branch, the second branch, the third branch, the fourth branch, the fifth branch, the sixth branch, the seventh branch, the eighth branch, and the ninth branch. The first branch and the ninth branch are connected in parallel between the first power line and the second power line. A start button, a pressure upper limit relay contact, and a pneumatic valve relay coil are provided on the first branch. A pneumatic valve relay contact and a pneumatic solenoid valve are provided on the ninth branch. One end of the second branch is connected to the first branch. Both ends of the third branch are connected to the first branch and the second branch in a one-to-one correspondence. A pneumatic valve relay contact is provided on the third branch. The pneumatic valve relay contact on the third branch is connected in parallel with the start button on the first branch. The fourth branch, The fifth branch and the sixth branch are connected in parallel between the second branch and the second power line. The fourth branch is provided with an upper pressure limit relay contact and an upper pressure limit relay coil. The fifth branch is provided with a pneumatic valve relay contact, a pressure gauge, and a lower pressure limit relay coil. The first end of the pressure gauge is connected to the fourth branch. The sixth branch is provided with an upper pressure limit relay contact and a pressure maintaining relay coil. The seventh branch is provided with a pressure maintaining relay contact, a lower pressure limit relay contact, and a first alarm mechanism for indicating unqualified information. The two ends of the eighth branch are connected to the seventh branch and the second power line in a one-to-one correspondence. The eighth branch is provided with a lower pressure limit relay contact and a second alarm mechanism for indicating qualified information. The pneumatic valve relay contacts include: a first contact, a second contact, and a third contact, wherein the first contact is located on the third branch, the first contact is connected in parallel with the start button, the second contact is located on the fifth branch, and the third contact is located on the ninth branch; The pressure upper limit relay contacts include: a fourth contact, a fifth contact, and a sixth contact, wherein the fourth contact is located on the first branch, the fifth contact is located on the fourth branch, and the sixth contact is located on the sixth branch; The pressure lower limit relay contacts include: a seventh contact and an eighth contact, wherein the seventh contact is located on the seventh branch, and the eighth contact is located on the eighth branch; A stop button is provided on the first branch line, one end of the stop button is connected to the first power line, and the other end of the stop button is connected to the start button; It also includes: a bracket and a pneumatic control system, wherein the pneumatic control system is installed on the bracket and connected to the pneumatic solenoid valve.

2. A power mechanism sealing test device according to claim 1, characterized in that: The first alarm mechanism and the second alarm mechanism are both alarm lights.

3. The power mechanism sealing test device according to claim 1, characterized in that: The pressure gauge is an electric contact pressure gauge with a range of 0-0.1 MPa.

4. The power mechanism sealing test device according to claim 1, characterized in that: The first power line and the second power line are connected to a 24V power source.

5. A power mechanism sealing test method, characterized in that: Based on the power mechanism sealing test device according to any one of claims 1 to 4 above, the power mechanism sealing test method includes: S1. Click the start button, the pneumatic valve relay contacts close, the pneumatic solenoid valve opens, and compressed air is filled into the power mechanism; S2. When the pressure inside the power mechanism reaches the upper limit pressure value of the pressure gauge, the upper limit pressure relay contacts are closed, the pneumatic valve relay contacts are disconnected, the pressure holding relay contacts are normally open, the timing starts, the pneumatic solenoid valve closes, and the compressed air supply to the power mechanism stops; S3, when the timing is completed, the pressure-maintaining relay contacts are closed; S4. If the pressure value of the pressure gauge is greater than the lower limit value, the contact of the lower limit pressure relay is disconnected, which is used to indicate that the qualified second alarm mechanism is working; S5. If the pressure value of the pressure gauge is less than the lower limit value, the contact of the lower limit pressure relay is closed, and the first alarm mechanism for indicating unqualified information is activated; S6. Remove the power mechanism and click the stop button to complete the test.

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