Four-way solenoid valve in our production applications are a lot, and its working principles are as follows:
When there is current through the coil, it produces excitation effect, fixed-iron core pull-moving core, moving iron core drives sliding spool and compress spring, changing the sliding spool position, thus changing the flow direction. When the coil loses power, depending on * elastic spring to promote sliding spool, back moving core, so that fluid flows the original direction. In our oxygen production, molecular sieve switching system forced valve switches are controlled through two-position four-way solenoid valve, the airflow is respectively supplied to the two piston ends of the forced valve. In order to control the force valve open and close. Solenoid valve failure will directly affect the switching valve and control valve movements, common faults are solenoid valves without action, we should start to troubleshoot the following areas:
（1） Solenoid valve wiring loose or end off, solenoid valve fasten end without gaining electricity.
（2） Solenoid VALVE coil is burn out, removing the solenoid valve wiring, using multimeter to measure, if open, then the solenoid valve coil is burn out. The reasons are coils have been damp, magnetic flux leakage caused by bad insulation, resulting in the winding currents are too large to burn, so need to prevent flood water entering solenoid valve. In addition, the spring is too hard, reaction is too large, the coil turns too few, not enough suction makes the coil can also be burned. Emergency management, can turn the normal working "0" bit to "1" bit of manual button on the coil, making valve opened.
（3）Solenoid valve locks. Solenoid valve slide sleeve and spool gap is too small (less than 0.008mm), are generally one-piece assembly, when there are mechanical impurities or too little lubricant, it is easy to get stuck. Dealing method is using holes hold into the wire from the head to make it bounce. The fundamental solution is to remove the solenoid valve, remove the spool and spool cover, cleaned with CCI4, making the valve spool comprising a flexible movement. Demolition should pay attention to the various components of the assembly sequence and location of the external wiring for re-assembly and wiring is correct, and also check the lubricator oil spray holes whether are blocked, and whether lubricating oil is adequate.
（4）Leakage. Lack of air pressure can cause leakage, making forced valve difficult to open and close, the reason is sealing gasket is damaged or sliding valve is weared to cause a few cavities channeling gas.
in dealing with switched systems electromagnetic valve failures, should choose an appropriate time, and dealing when the solenoid valve is in a loss of power, if can not finished within a switch gap, you can stop the switch system and handle calm.