Failure And Improvement Of Switching Valve

The switching valve consists of a gas filter, a solenoid valve, and a three-way valve. When the time relay gives a signal and the solenoid valve 2 is energized, a small amount of compressed air enters the three-way valve cylinder B chamber through the filter and the solenoid valve. Under the pressure difference at both ends of the guide piston, the guide valve disc moves to the right, and the 5-6 valve disc presses the compressed air (positive flow) into the plate-type cold storage channel A→D. If the time relay gives an opposite signal to the solenoid valve again, the guide valve disc returns to the first working position (that is, the positive flow gas cannot enter the plate-type cold storage, and the reflux gas is discharged outside the tower). In this way, the two switching valves work together in a cycle to achieve the purpose of circulating and exchanging the positive flow gas and the reflux gas in the plate-type cold storage to continuously remove the moisture and carbon dioxide in the air entering the tower. The switching time is generally controlled within 2-3 minutes.
If the switching valve is stuck, that is, the three-way valve A→D channel and D→C channel cannot be switched (the three-way valve guide valve disc is stuck at the left and right extremes) or the A→D channel and the D→C channel are interconnected (the three-way valve guide valve disc is stuck in any position in the middle, and the 5-6 and 7-8 valve discs are not related to the dead channel, this phenomenon is the most common), the plate-type cold storage device cannot work normally and the working condition will be destroyed.
Reduce the deformation of the three-way valve body. Since 1982, the wall thickness of the three-way valve body has been increased to increase the strength. In 1997, the hard connection of all channels of the three-way valve was changed to the hard connection of the D and C channels, and the A channel was connected to the bellows transition, which greatly reduced the deformation of the valve body and effectively prevented the occurrence of the three-way valve stuck in the early stage of work.
Change the auxiliary piston "soft connection" to "hard connection" to avoid the piston loosening and tilting. The size of the piston rod is appropriately increased from the original diameter of 12 mm to 13.4 mm, thereby increasing the shaft shoulder; the auxiliary piston is changed from a concave type to a convex type, so that the auxiliary piston is directly connected to the valve plate.