Device and method for testing service life of pressure switch

Abstract

The invention discloses a pressure switch service life testing device, which comprises an air path system, wherein air is blown by an air compressor to reach a buffer air cylinder and then reaches a tested pressure switch through an electromagnetic valve; the electrical control system comprises a switching power supply and three branches connected with the switching power supply, the first branch comprises a switch SA and a pressure switch contact SP, the pressure switch contact SP is normally closed, and the on-off of the branch is controlled through the switch SA; the second branch is connected with a time relay KT and an electromagnetic valve coil, the on-off speed of the electromagnetic valve coil is controlled by arranging the time relay KT, and a port communicated with the interior of the electromagnetic valve is switched; the third branch comprises a tested pressure switch contact and an indicating lamp which are connected, and the action state of the tested pressure switch is identified through the indicating lamp. According to the invention, unattended operation can be realized, the action times of the pressure switches can be automatically tested and recorded, and whether the batch of pressure switches meet the service life requirement can be conveniently mastered.

Description

Technical Field

[0001] The invention belongs to the technical field of testing equipment, and in particular relates to a device and a testing method for detecting the service life and operating pressure value of a pressure switch. Background Art

[0002] Pressure switches are widely used in energy and mining, machinery manufacturing and processing, healthcare, rail transportation and other industries. Pressure switches are an automated controller that monitors changes in pressure and sends a signal to control machine operation when a preset value is reached. Its working principle is based on the mechanism of spring deformation. When external pressure is applied, the pressure switch spring deforms and triggers the switch, generating a corresponding control signal.

[0003] With the development of technology, there are increasingly higher requirements for the service life and action accuracy of pressure switches. Only when the pressure switch remains stable can the stable operation of various equipment be guaranteed. There is no more suitable method in the prior art for detecting the service life of the pressure switch. For the pressure value detection of the pressure switch, the accuracy of the initial pressure value can only be detected when the pressure switch is inspected upon entry, and it is impossible to detect whether the pressure value is accurate after long-term use. At the same time, due to the large number of pressure switches, only random inspections can be carried out on each batch when the pressure switch enters the site. When multiple pressure switches are inspected, the inspection takes a long time, affecting the production progress. Summary of the invention

[0004] In view of the above-mentioned defects, the present invention provides a pressure switch life testing device and method, which can detect the service life and operating pressure value of the pressure switch. The cyclic detection has high accuracy and short detection time, and is suitable for industrial promotion.

[0005] A pressure switch life test device includes an air circuit system for introducing air pressure and an electrical control system for controlling the on and off of the pressure switch.

[0006] An air circuit system comprises an air compressor 2, a buffer air cylinder 6, a solenoid valve 12 and a pressure switch 14 to be tested, which are connected in sequence. A pressure gauge is provided on the passage between the solenoid valve 12 and the buffer air cylinder 6. A control pressure switch 8 is provided on the buffer air cylinder 6. The solenoid valve 12 has an air inlet, an air outlet and a pressure relief port. The solenoid valve air inlet 1201 is connected to the buffer air cylinder 6, the solenoid valve air outlet 1203 is connected to the pressure switch 14 to be tested, the solenoid valve pressure relief port 1202 is connected to the outside world, and the solenoid valve coil 1204 gains and loses power corresponding to the two states that the solenoid valve air inlet 1201 is connected to the solenoid valve air outlet 1203, or the solenoid valve air outlet 1203 is connected to the solenoid valve pressure relief port 1202;

[0007] The electrical control system includes a switching power supply 16, which is connected to three branches. The first branch includes a switch SA and a pressure switch contact SP 801. The pressure switch contact SP 801 is normally closed, and the on-off of this branch is controlled by the switch SA; the second branch includes a time relay KT 19 and a solenoid valve coil 1204 connected to each other. The on-off speed of the solenoid valve coil is controlled by setting the on-off time of the time relay KT 19, and the port connected inside the solenoid valve 12 is switched; the third branch includes a tested pressure switch contact 1402 and an indicator light 21 connected to each other, and the operating state of the tested pressure switch 14 is identified by the indicator light 21.

[0008] Preferably, the electrical control system is also connected to an AC220V power supply 15, which is connected to a single-phase AC motor M201 and a switching power supply 16 as a power supply; a contactor normally open contact KM is provided between the AC220V power supply 15 and the single-phase AC motor M201, and a contactor KM18 is also connected to the first branch. When the switch SA and the pressure switch contact SP 801 are both closed, the single-phase AC motor M201 drives the air compressor 2 to work.

[0009] Preferably, a counter PC 20 is also connected to the second branch, and the counter PC 20 is connected in parallel to both ends of the solenoid valve coil 1204 to record the cumulative number of actions of the tested pressure switch 14 .

[0010] Preferably, the air circuit system further includes an air filter 1 and a fine filter 10, wherein the air filter 1 is arranged at the inlet of the air compressor 2, and the fine filter 10 is arranged between the outlet of the buffer air cylinder 6 and the air inlet 1201 of the solenoid valve.

[0011] Preferably, the air circuit system further includes a radiator 4 , which is arranged between the outlet of the air compressor 2 and the inlet of the buffer air cylinder 6 .

[0012] Preferably, the gas circuit system further includes a muffler 13, and the muffler 13 is arranged at the pressure relief port 1202 of the solenoid valve to reduce the exhaust noise during pressure relief.

[0013] Preferably, the pressure switch 14 to be tested is a plurality of groups of pressure switches connected in parallel, and one pressure switch corresponds to a series-connected pressure switch contact 1402 and indicator light 21 to be tested.

[0014] The present invention also discloses a test method for a pressure switch life test device, based on the pressure switch life test device, comprising the following steps:

[0015] Step 1, the air compressor 2 works, the internal pressure of the buffer air cylinder 6 gradually rises, and the internal pressure of the buffer air cylinder 6 reaches the tested pressure switch 14 through the solenoid valve 12;

[0016] Step 2, the pressure of the tested pressure switch 14 gradually rises. When a certain status indicator light 21 is observed to light up for the first time, the pressure value of the pressure gauge at this time is recorded, which is the action pressure value of the corresponding tested pressure switch 14. The action pressure values ​​of all tested pressure switches 14 are recorded in sequence;

[0017] Step 3, when the pressure value is greater than the threshold of the buffer air cylinder 6, the control pressure switch contact SP 801 is disconnected, the contactor KM18 coil loses power, and the pressure gradually decreases. When the pressure value is less than the control pressure switch 8 connection pressure, the control pressure switch contact SP 801 is connected, the contactor KM 18 coil is energized and attracted, the contactor normally open contact KM 1801 is closed, the single-phase AC motor M201 is energized and starts running, and the air compressor 2 blows air to maintain the internal pressure of the unit within a certain range.

[0018] Preferably, the on-off frequency of the time relay KT 19 is set to control the energizing and de-energizing cyclic operation of the solenoid valve coil 1204. When the solenoid valve coil 1204 is de-energized, the internal pressure of the buffer air cylinder 6 reaches the tested pressure switch 14 through the solenoid valve 12; when the solenoid valve coil 1204 is energized, the pipeline between the buffer air cylinder 6 and the tested pressure switch 14 is cut off, and the internal pressure of the pipeline between the tested pressure switch 14 and the solenoid valve 12 is released through the solenoid valve pressure relief port 1202.

[0019] The beneficial effects of the present invention are:

[0020] (1) The pressure switch life test device disclosed in the present invention can be unattended, automatically test and record the number of pressure switch operations, and facilitate the understanding of whether the pressure switches in this batch meet the service life requirements;

[0021] (2) The pressure switch life test device of the present invention is convenient for detecting whether the operating pressure value of the pressure switch drifts after long-term use and whether it still meets the use requirements.

[0022] (3) The pressure switch life test device disclosed in the present invention can test multiple pressure switches at the same time, shortening the test time and quickly grasping the quality of products in the same batch. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below.

[0024] Figure 1 It is a schematic diagram of a gas circuit system of one embodiment of the invention;

[0025] Figure 2 It is a schematic diagram of an electrical control system of an embodiment of the invention;

[0026] Figure markings: 1-air filter, 2-air compressor, 3-high-pressure hose, 4-radiator, 5-check valve, 6-buffer air cylinder, 7-safety valve, 8-control pressure switch, 9-drain valve, 10-fine filter, 11-test connector, 12-solenoid valve, 1201-solenoid valve air inlet, 1202-solenoid valve pressure relief port, 1203-solenoid valve air outlet, 13-muffler, 14-tested pressure switch, 1401-tested pressure switch interface, 1402-tested pressure switch contact, 15-AC220V power supply, 201-single-phase AC motor M, 16-switching power supply, 18-contactor KM, 1801-contactor normally open contact KM, 801-control pressure switch contact SP, 17-knob switch SA, 19-time relay KT, 1204-solenoid valve coil, 20-counter, 21-status indicator light. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments 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.

[0028] Example 1

[0029] An embodiment of the present invention provides a pressure switch life test device, comprising an air circuit system for introducing air pressure and an electrical control system for controlling the on and off of all switches in the air circuit system.

[0030] Gas system, such as Figure 1 As shown, it includes an air filter 1, an air compressor 2, a high-pressure hose 3, a radiator 4, a one-way valve 5, a buffer air cylinder 6, a safety valve 7, a control pressure switch 8, a drain valve 9, a fine filter 10, a test connector 11, a solenoid valve 12, a muffler 13 and a pressure switch to be tested 14.

[0031] The inlet of the air compressor 2 is connected to the air filter 1, and the outlet is connected to the inlet of the radiator 4 through the high-pressure hose 3. The air compressor 2 is driven by a single-phase AC motor 201. The outlet of the radiator 4 is connected to the inlet of the buffer air cylinder 6 through the one-way valve 5, and the outlet of the buffer air cylinder 6 is connected to the inlet of the fine filter 10. The outlet of the fine filter 10 is connected to the air inlet 1201 of the solenoid valve, and the air outlet 1203 of the solenoid valve is connected to the tested pressure switch interface 1401. In order to realize the simultaneous detection of multiple pressure switches, in this embodiment, the tested pressure switch interface 1401 is divided into 6 branches, which can be connected to 6 tested pressure switches 14 at the same time. The test time of this batch of pressure switches is greatly shortened, and the test and production efficiency are improved.

[0032] A test connector 11 is provided between the fine filter 10 and the solenoid valve 12, which can be connected to an external pressure gauge to test and record the operating pressure value of the tested pressure switch 14. At the same time, it monitors whether the internal pressure of the unit is within the pressure range required for the test.

[0033] Electrical control systems, such as Figure 2 As shown, it includes an AC220V power supply 15, a single-phase AC motor M201, a switching power supply 16, a contactor KM18, a control pressure switch contact SP801, a knob switch SA17, a time relay KT19, a solenoid valve coil 1204, a counter 20, a tested pressure switch contact 1402 and a status indicator light 21.

[0034] AC220V power supply 15 is used as the power supply for single-phase AC motor M201 and switch power supply 16. Single-phase AC motor M201 is connected to AC220V power supply 15 through contactor normally open contact KM1801. At the same time, AC220V power supply 15 is connected to the input end of switch power supply 16, and converted into DC24V power supply after passing through switch power supply 16. DC24V power supply is connected to 3 branches. The first branch: the coil of contactor KM18 is connected to the output end of switch power supply 16 after controlling pressure switch contact SP801 and knob switch SA17; the second branch: the time relay KT19 is connected to the output end of switch power supply 16 after connecting to the solenoid valve coil 1204, and the counter PC20 is connected in parallel to both ends of the solenoid valve coil 1204; the third branch: the contacts 1402 of the 6 tested pressure switches are respectively connected to a status indicator light 21 and then connected to the output end of switch power supply 16. Each tested pressure switch 14 corresponds to a status indicator light 21.

[0035] The buffer air cylinder 6 is provided with a safety valve 7, a control pressure switch 8 and a drain valve 9. The safety valve 7 prevents the unit from overpressure protection when the system operates abnormally; the drain valve 9 is used to discharge the remaining water in the buffer air cylinder 6. The control pressure switch 8 is a dual-value pressure switch, and the connection pressure and disconnection pressure can be set separately. In this test device, the control pressure switch contact SP 801 is connected when the pressure is less than 750kPa, and the control pressure switch contact SP 801 is disconnected when the pressure is greater than 900kPa. By controlling the pressure switch 8, the internal pressure of the unit is automatically detected, the start and stop of the air compressor 2 is controlled, and the internal pressure of the unit is maintained between 750kPa and 900kPa to ensure the pressure required for the test.

[0036] The solenoid valve 12 has a solenoid valve air inlet 1201, a solenoid valve pressure relief port 1202, and a solenoid valve air outlet 1203. The working state of the solenoid valve 12 is: when the solenoid valve coil 1204 loses power, the solenoid valve air inlet 1201 and the solenoid valve air outlet 1203 are connected; when the solenoid valve coil 1204 is powered, the solenoid valve air outlet 1203 and the solenoid valve pressure relief port 1202 are connected. A muffler 13 is provided at the solenoid valve pressure relief port 1202. It is used to reduce the exhaust noise when the pressure switch 14 under test is released.

[0037] The time relay KT 19 can set the on time and off time. In order to increase the test frequency and shorten the test time, the on time is set to 1 second and the off time is set to 1 second in this test device. When the time relay KT 19 is working, it automatically connects for 1 second and disconnects for 1 second, and works in a cycle.

[0038] When the counter PC 20 is working, it counts once when it is powered on. After power failure, the count is saved and not cleared, and the count is accumulated when it is powered on next time. It is convenient to record the cumulative number of actions of the tested pressure switch 14 in real time and grasp its service life.

[0039] The tested pressure switch 14 is a single-value pressure switch with only one operating pressure value of 500 kPa. When the pressure value is less than 500 kPa, the tested pressure switch contact 1402 is disconnected, and when the pressure value is greater than 500 kPa, the tested pressure switch contact 1402 is connected.

[0040] Example 2

[0041] The present invention also discloses a method for testing a pressure switch life test device, comprising the following steps:

[0042] Step 1: Connect the pressure gauge to the test connector 11, turn on the AC220V power supply 15, and turn on the knob switch SA 17. At this time, the coil of the contactor KM 18 is energized and attracted, the normally open contact KM 1801 of the contactor is closed, the single-phase AC motor M 201 is energized and starts to run, the air compressor 2 blows, and the internal pressure of the buffer air cylinder 6 gradually rises.

[0043] Step 2: Set the cycle time required by the time relay KT 19. In this embodiment, the time relay KT 19 controls the electromagnetic valve coil 1204 to be energized for 1 second and de-energized for 1 second to cycle. When the electromagnetic valve coil 1204 is de-energized, the internal pressure of the buffer air cylinder 6 reaches the tested pressure switch 14 through the electromagnetic valve 12; when the electromagnetic valve coil 1204 is energized, the pipeline between the buffer air cylinder 6 and the tested pressure switch 14 is cut off, and the internal pressure of the pipeline between the tested pressure switch 14 and the electromagnetic valve 12 is released through the electromagnetic valve pressure relief port 1202.

[0044] Step 3: As the pressure rises to about 500 kPa, when a certain status indicator light 21 is observed to light up for the first time, record the pressure value of the pressure gauge at this time, which is the action pressure value of the corresponding tested pressure switch 14. Record the action pressure values ​​of the six tested pressure switches 14 in sequence.

[0045] Step 4: The air compressor 2 continues to run, and the pressure continues to rise. When the pressure value is greater than the disconnection pressure of the control pressure switch 8, 900kPa, the control pressure switch contact SP 801 is disconnected, the contactor KM 18 coil loses power, and the contactor normally open contact KM 1801 is disconnected, the air compressor 2 is powered off, stops running, and completes a test cycle. As the compressed air inside the unit is consumed, the pressure gradually decreases. When the pressure value is less than the control pressure switch 8 connection pressure of 750kPa, the control pressure switch contact SP 801 is connected, the contactor KM 18 coil is energized and attracted, the contactor normally open contact KM 1801 is closed, the single-phase AC motor M201 is energized and starts running, and the air compressor 2 blows air to maintain the internal pressure of the unit between 750kPa and 900kPa, and repeat the above steps until all pressure switch life tests are completed.

[0046] In addition, the solenoid valve 12 is controlled by the time relay KT 19 to continuously cycle on and off. Since the internal set pressure value of the unit (750kPa-900kPa) is higher than the operating pressure value (500kPa) of the tested pressure switch 14, the tested pressure switch 14 can be operated every time it receives pressure. Therefore, the tested pressure switch 14 will also be connected for 1 second and disconnected for 1 second according to the operating frequency of the solenoid valve 12, and the operating state of the tested pressure switch 14 can be identified through the corresponding status indicator 21. The counter 20 counts once each time the solenoid valve coil 1204 is energized, and automatically records the cumulative number of operations.

[0047] When a certain status indicator light 21 is off, and the other status indicator lights 21 are normally on and off, it can be determined that the corresponding tested pressure switch 14 has failed. At this time, the number of actions recorded by the counter 20 is the life of the tested pressure switch 14.

[0048] After every 8 hours of operation, turn off the knob switch SA 17, open the drain valve 9 below the buffer air cylinder 6, drain the internal pressure of the unit and then close the drain valve 9. Restart the operation and record the action pressure value of the tested pressure switch 14 once, so as to understand the drift of the action pressure value of the tested pressure switch after each period of operation and whether it meets the use requirements.

[0049] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pressure switch life test device, characterized in that: The invention comprises an air circuit system and an electrical control system, wherein the air circuit system comprises an air compressor (1), a buffer air cylinder (6), a solenoid valve (12) and a pressure switch (14) to be tested, which are connected in sequence. A pressure gauge is provided on the passage between the solenoid valve 12 and the buffer air cylinder (6), and a control pressure switch (8) is provided on the buffer air cylinder (6). The solenoid valve (12) has an air inlet, an air outlet and a pressure relief port. The solenoid valve air inlet (1201) is connected to the buffer air cylinder (6), the solenoid valve air outlet (1203) is connected to the pressure switch (14) to be tested, and the solenoid valve pressure relief port (1202) is connected to the outside world. The solenoid valve coil (1204) is energized or deenergized in two states, corresponding to the solenoid valve air inlet (1201) being connected to the solenoid valve air outlet (1203), or the solenoid valve air outlet (1203) being connected to the solenoid valve pressure relief port (1202). The electrical control system comprises a switch power supply (16), wherein the switch power supply (16) is connected to three branches, wherein the first branch comprises a switch SA and a pressure switch contact SP (801), wherein the pressure switch contact SP (801) is normally closed, and the switch SA is used to control the on / off of the branch; the second branch comprises a time relay KT (19) and a solenoid valve coil (1204) connected to each other, wherein the on / off speed of the solenoid valve coil is controlled by setting the on / off time of the time relay KT (19), and the ports connected inside the solenoid valve (12) are switched; and the third branch comprises a tested pressure switch contact (1402) and an indicator light (21) connected to each other, wherein the operating state of the tested pressure switch (14) is identified by the indicator light (21).

2. The pressure switch life test device according to claim 1, characterized in that: The electrical control system is also connected to an AC220V power supply (15), and the AC220V power supply (15) is connected to a single-phase AC motor M (201) and a switch power supply (16) as a power supply; a contactor normally open contact KM (1801) is provided between the AC220V power supply (15) and the single-phase AC motor M (201), and a contactor KM (18) is also connected to the first branch circuit. When the switch SA and the pressure switch contact SP (801) are both closed, the single-phase AC motor M (201) drives the air compressor (2) to work.

3. The pressure switch life test device according to claim 1, characterized in that: The second branch is also connected to a counter PC (20), which is connected in parallel to both ends of the solenoid valve coil (1204) to record the cumulative number of operations of the tested pressure switch (14).

4. The pressure switch life test device according to claim 1, characterized in that: The control pressure switch (8) is a dual-value pressure switch, and can set a switch-on pressure and a switch-off pressure respectively.

5. The pressure switch life test device according to claim 1, characterized in that: The air circuit system further comprises an air filter (1) and a fine filter (10), wherein the air filter (1) is arranged at the inlet of the air compressor (2), and the fine filter (10) is arranged between the outlet of the buffer air cylinder (6) and the air inlet (1201) of the solenoid valve.

6. The pressure switch life test device according to claim 1, characterized in that: The air circuit system further comprises a radiator (4), wherein the radiator (4) is arranged between the outlet of the air compressor (2) and the inlet of the buffer air cylinder (6).

7. The pressure switch life test device according to claim 1, characterized in that: The gas circuit system further comprises a muffler (13), wherein the muffler (13) is arranged at the pressure relief port (1202) of the solenoid valve to reduce exhaust noise during pressure relief.

8. The pressure switch life test device according to claim 1, characterized in that: The pressure switch (14) to be tested is a plurality of groups of pressure switches connected in parallel, and one pressure switch corresponds to a series-connected pressure switch contact (1402) and an indicator light (21) to be tested.

9. A method for testing a pressure switch life test device, characterized in that: The testing device according to any one of claims 2 to 8 comprises the following steps: Step 1, the air compressor (2) works, the internal pressure of the buffer air cylinder (6) gradually rises, and the internal pressure of the buffer air cylinder (6) reaches the tested pressure switch (14) through the solenoid valve (12); Step 2, the pressure of the tested pressure switch (14) gradually rises, and when a certain status indicator light (21) is observed to light up for the first time, the pressure value of the pressure gauge at this time is recorded, which is the action pressure value of the corresponding tested pressure switch (14), and the action pressure values ​​of all tested pressure switches (14) are recorded in sequence; Step 3, when the pressure value is greater than the threshold value of the buffer air cylinder (6), the control pressure switch contact SP (801) is disconnected, the contactor KM (18) coil loses power, and the pressure gradually decreases. When the pressure value is less than the control pressure switch (8) connection pressure, the control pressure switch contact SP (801) is connected, the contactor KM (18) coil is energized and attracted, the contactor normally open contact KM1 (801) is closed, the single-phase AC motor M (201) is energized and starts to run, and the air compressor (2) blows air to maintain the internal pressure of the unit within a certain range.

10. The testing method of the pressure switch life testing device according to claim 9, characterized in that: The on-off frequency of the time relay KT (19) is set to control the electromagnetic valve coil (1204) to circulate between power on and power off. When the electromagnetic valve coil (1204) is de-energized, the internal pressure of the buffer air cylinder (6) reaches the tested pressure switch (14) through the electromagnetic valve (12); when the electromagnetic valve coil (1204) is energized, the pipeline between the buffer air cylinder (6) and the tested pressure switch (14) is cut off, and the internal pressure of the pipeline between the tested pressure switch (14) and the electromagnetic valve (12) is released through the electromagnetic valve pressure relief port (1202).

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