The electromagnetic reversing valve uses the electromagnet to push the spool to move to change the direction of the liquid flow. According to the power used by the electromagnet, it can be divided into two types: AC (110V, 220V, 380V) and DC (12V, 24V, 36V, 110V).

 

     From the appearance, AC electromagnets are mostly square with heat sinks, and DC electromagnets are mostly cylindrical. The AC electromagnet has a large starting force, does not require a special power supply, and has a fast pull-in and release (about 0.01-0.03s), but the reversing impact is large and the noise is large, so the reversing frequency should not be too high (no more than 30 times/minute), If the spool is stuck or the frictional resistance is high and the armature is not in place, the coil will be burned out due to excessive current, so the reliability is poor.

 

     The DC electromagnet has high working reliability, low noise, small commutation impact, and high commutation frequency (allowing 120 times/min, even up to 200 times/min). If the armature fails to pull in normally for some reason, the coil will not be burned out, but its starting force is small, the commutation time is long, and it needs a DC power supply.

 

     According to whether there is oil in the working chamber of the armature, the electromagnetic reversing valve can be divided into two types: dry type and wet type. The dry electromagnet does not allow oil to flow into the electromagnet, so a sealing device is provided between the slide valve and the electromagnet. However, the frictional resistance at the seal is relatively large, which affects the reliability of the reversing and easily causes the leakage of the reversing valve. The armature and push rod of the wet electromagnet are completely immersed in the oil, and there is no need for a sealing device between the relative moving parts, thereby reducing the movement resistance of the valve core and improving the reliability of the reversing, and there is no dynamic seal, which is not easy to leak .

 

     In addition, the oil also plays the role of lubrication, cooling and vibration absorption, which reduces the suction loss of the wet electromagnet and prolongs the service life of the electromagnet. Dry electromagnets generally only work 500,000 to 600,000 times, while wet electromagnets can work 10 million times. Wet electromagnets have good performance, but are slightly more expensive.