Solenoid valves are widely used in our production. We must have encountered many problems related to solenoid valves in the maintenance of production, and have also dealt with various faults. Everyone must have accumulated a lot of experience in dealing with solenoid valve faults. I have dealt with solenoid valve faults relatively less than other instrumentation faults in maintenance. Now let's discuss this issue with you.
Let's first have a preliminary understanding of the solenoid valve. The solenoid valve is composed of an electromagnetic coil and a magnetic core, and is a valve body containing one or several holes. When the coil is energized or de-energized, the operation of the magnetic core will cause the fluid to pass through the valve body or be cut off to achieve the purpose of changing the direction of the fluid. The electromagnetic components of the solenoid valve are composed of a fixed iron core, a moving iron core, a coil and other components; the valve body is composed of a sliding valve core, a sliding valve sleeve, a spring base and the like. The electromagnetic coil is directly installed on the valve body, and the valve body is enclosed in a sealing tube, forming a simple and compact combination. The solenoid valves commonly used in our production are two-position three-way, two-position four-way, two-position five-way, etc. Here we first talk about the meaning of two positions: for the solenoid valve, it is energized and de-energized, and for the controlled valve, it is open and closed.
In our oxygen generator instrumentation and control system, two-position three-way solenoid valves are used more frequently. It can be used to connect or cut off the gas source in production, thereby switching the pneumatic control membrane head gas path.
It consists of valve body, valve cover, solenoid assembly, spring and sealing structure. The sealing block at the bottom of the moving iron core closes the valve body air inlet with the help of the spring pressure. After power is turned on, the electromagnet is attracted, and the sealing block with spring on the upper part of the moving iron core closes the exhaust port, and the air flow enters the membrane head from the air inlet, which plays a control role. When the power is lost, the electromagnetic force disappears, and the moving iron core leaves the fixed iron core under the action of the spring force, moves downward, opens the exhaust port, blocks the air inlet, and the membrane head air flow is discharged through the exhaust port, and the diaphragm returns to its original position. In our oxygen production equipment, it is used in the emergency cut-off of the membrane regulating valve at the inlet of the turbine expander.
Four-way solenoid valves are also widely used in our production. Their working principle is as follows:
When current passes through the coil, an excitation effect is generated, the fixed iron core attracts the moving iron core, and the moving iron core drives the sliding valve core and compresses the spring, changing the position of the sliding valve core and thus changing the direction of the fluid. When the coil loses power, the elastic force of the spring pushes the sliding valve core and pushes the moving iron core back, so that the fluid flows in the original direction. In our oxygen production, the switch of the forced valve of the molecular sieve switching system is controlled by a two-position four-way solenoid valve, and the air flow is supplied to the two ends of the piston of the forced valve. Thus, the opening and closing of the forced valve is controlled.
The failure of the solenoid valve will directly affect the action of the switching valve and the regulating valve. Common failures include the failure of the solenoid valve to act. The following aspects should be checked:
(1) The solenoid valve wiring head is loose or the wire head is detached. The solenoid valve must not be powered on, and the wire head can be tightened.
(2) If the solenoid valve coil is burned out, the wiring of the solenoid valve can be removed and measured with a multimeter. If it is open, the solenoid valve coil is burned out. The reason is that the coil is damp, causing poor insulation and magnetic leakage, resulting in excessive current in the coil and burning. Therefore, rainwater should be prevented from entering the solenoid valve. In addition, the spring is too hard, the reaction force is too large, the number of coil turns is too small, and the suction force is insufficient, which can also cause the coil to burn. In emergency treatment, the manual button on the coil can be turned from the "0" position during normal operation to the "1" position to open the valve.
(3) The solenoid valve is stuck. The matching clearance between the sliding valve sleeve and the valve core of the solenoid valve is very small (less than 0.008mm). It is generally assembled in one piece. When mechanical impurities are brought in or there is too little lubricating oil, it is easy to get stuck. The solution is to use a steel wire to poke it through the small hole in the head to make it rebound. The fundamental solution is to disassemble the solenoid valve, take out the valve core and valve core sleeve, and clean it with CCI4 so that the valve core can move flexibly in the valve sleeve. When disassembling, pay attention to the assembly sequence of each component and the external wiring position to facilitate reassembly and wiring. Also check whether the oil mist spray hole is blocked and whether there is enough lubricating oil.
(4) Leakage. Leakage will cause insufficient air pressure, making it difficult to open and close the forced valve. The reason is that the sealing gasket is damaged or the slide valve is worn, causing several cavities to leak air.
When dealing with the solenoid valve failure of the switching system, you should choose the appropriate time and wait until the solenoid valve is de-energized to handle it. If it cannot be handled within a switching gap, the switching system can be paused and handled calmly.
Solenoid valves are widely used in our production. We must have encountered many problems related to solenoid valves in the maintenance of production, and have also dealt with various faults. Everyone must have accumulated a lot of experience in dealing with solenoid valve faults. I have dealt with solenoid valve faults relatively less than other instrumentation faults in maintenance. Now let's discuss this issue with you.
Let's first have a preliminary understanding of the solenoid valve. The solenoid valve is composed of an electromagnetic coil and a magnetic core, and is a valve body containing one or several holes. When the coil is energized or de-energized, the operation of the magnetic core will cause the fluid to pass through the valve body or be cut off to achieve the purpose of changing the direction of the fluid. The electromagnetic components of the solenoid valve are composed of a fixed iron core, a moving iron core, a coil and other components; the valve body is composed of a sliding valve core, a sliding valve sleeve, a spring base and the like. The electromagnetic coil is directly installed on the valve body, and the valve body is enclosed in a sealing tube, forming a simple and compact combination. The solenoid valves commonly used in our production are two-position three-way, two-position four-way, two-position five-way, etc. Here we first talk about the meaning of two positions: for the solenoid valve, it is energized and de-energized, and for the controlled valve, it is open and closed.
In our oxygen generator instrumentation and control system, two-position three-way solenoid valves are used more frequently. It can be used to connect or cut off the gas source in production, thereby switching the pneumatic control membrane head gas path.
It consists of valve body, valve cover, solenoid assembly, spring and sealing structure. The sealing block at the bottom of the moving iron core closes the valve body air inlet with the help of the spring pressure. After power is turned on, the electromagnet is attracted, and the sealing block with spring on the upper part of the moving iron core closes the exhaust port, and the air flow enters the membrane head from the air inlet, which plays a control role. When the power is lost, the electromagnetic force disappears, and the moving iron core leaves the fixed iron core under the action of the spring force, moves downward, opens the exhaust port, blocks the air inlet, and the membrane head air flow is discharged through the exhaust port, and the diaphragm returns to its original position. In our oxygen production equipment, it is used in the emergency cut-off of the membrane regulating valve at the inlet of the turbine expander.
Four-way solenoid valves are also widely used in our production. Their working principle is as follows:
When current passes through the coil, an excitation effect is generated, the fixed iron core attracts the moving iron core, and the moving iron core drives the sliding valve core and compresses the spring, changing the position of the sliding valve core and thus changing the direction of the fluid. When the coil loses power, the elastic force of the spring pushes the sliding valve core and pushes the moving iron core back, so that the fluid flows in the original direction. In our oxygen production, the switch of the forced valve of the molecular sieve switching system is controlled by a two-position four-way solenoid valve, and the air flow is supplied to the two ends of the piston of the forced valve. Thus, the opening and closing of the forced valve is controlled.
The failure of the solenoid valve will directly affect the action of the switching valve and the regulating valve. Common failures include the failure of the solenoid valve to act. The following aspects should be checked:
(1) The solenoid valve wiring head is loose or the wire head is detached. The solenoid valve must not be powered on, and the wire head can be tightened.
(2) If the solenoid valve coil is burned out, the wiring of the solenoid valve can be removed and measured with a multimeter. If it is open, the solenoid valve coil is burned out. The reason is that the coil is damp, causing poor insulation and magnetic leakage, resulting in excessive current in the coil and burning. Therefore, rainwater should be prevented from entering the solenoid valve. In addition, the spring is too hard, the reaction force is too large, the number of coil turns is too small, and the suction force is insufficient, which can also cause the coil to burn. In emergency treatment, the manual button on the coil can be turned from the "0" position during normal operation to the "1" position to open the valve.
(3) The solenoid valve is stuck. The matching clearance between the sliding valve sleeve and the valve core of the solenoid valve is very small (less than 0.008mm). It is generally assembled in one piece. When mechanical impurities are brought in or there is too little lubricating oil, it is easy to get stuck. The solution is to use a steel wire to poke it through the small hole in the head to make it rebound. The fundamental solution is to disassemble the solenoid valve, take out the valve core and valve core sleeve, and clean it with CCI4 so that the valve core can move flexibly in the valve sleeve. When disassembling, pay attention to the assembly sequence of each component and the external wiring position to facilitate reassembly and wiring. Also check whether the oil mist spray hole is blocked and whether there is enough lubricating oil.
(4) Leakage. Leakage will cause insufficient air pressure, making it difficult to open and close the forced valve. The reason is that the sealing gasket is damaged or the slide valve is worn, causing several cavities to leak air.
When dealing with the solenoid valve failure of the switching system, you should choose the appropriate time and wait until the solenoid valve is de-energized to handle it. If it cannot be handled within a switching gap, the switching system can be paused and handled calmly.