The automatic valve is actually a kind of one-way valve, which is installed in the cold end and middle extraction of the switching heat exchanger. It is matched with the forced Valve. When going through the forward air, the automatic valve of air (and the Middle pumping air) opens, and the automatic valve of dirt nitrogen (or oxygen, nitrogen) closes; when going through the return air, the sewage and nitrogen automatic valve opens, and the air automatic valve closes. There are often multiple automatic valves in a valve box, and it is rare that failures occur at the same time. Therefore, its influence on pressure and flow is generally smaller than that of forced Valve.
The failure that the automatic valve can't be opened is rare, which mainly occurs in the start-up cooling stage. The automatic valve is frozen by water or stuck by grass chips, stone powder and so on in the Pebble, which causes the air extraction can't be extracted, or there is a big difference between the two groups of air flows. When the group with small flow flows air, the air tube pressure rises and the temperature in the middle part is lower, which indicates that some automatic air valves have not been opened. When part of the automatic sewage and nitrogen valves are not opened, the pressure of the upper tower will rise and the temperature of the middle part will be higher.
The common failure of the automatic valve is that the valve is not closed tightly, which causes the air in the cold end of the middle and low pressure. It reflects the increase of air flow and the decrease of pressure. And caused low-voltage system of pressure.
The failure of automatic valve also poses a great threat to the normal production of oxygen generator. Unable to open the automatic valve (or unable to open completely) will cause the resistance to increase, and the logistics of each heat exchange unit is unbalanced. Unable to open the middle pumping valve will interrupt the pumping and destroy the self-cleaning conditions.
The automatic valve is not closed strictly, and the air runs away from the heat exchanger, which will reduce the air flow into the tower and decrease the output of oxygen and nitrogen. Meanwhile, due to the increase of return flow, the cold loss at the hot end will increase, and in serious cases, the temperature at the hot end will drop sharply. In addition, when the automatic valve drops, overpressure accident of low-pressure system may occur.
