The operating cycle of the VPSA oxygen production process is very short, generally less than 1 min. In one cycle, each adsorption vessel needs to experience the steps of adsorption, pressure reduction, desorption, purging, even pressure increasing, etc.

Key valves switch on and off once in each cycle, which is pretty frequent, so they are required to be switched quite fast in order to improve the working efficiency and effective utilization of the oxygen plant.

Therefore, the valves used in VPSA oxygen plant must feature the following characteristics:

1. high switching speed

2. good sealing performance

3. long service life under frequent and fast switching conditions

4. oil-free operation

At present, domestic VPSA plants generally adopt special double-eccentric pneumatic butterfly valves whose actuators and pneumatic components are made by famous brands such as Metso and SMC to improve the reliability of the valves. The valve has the following characteristics:

1. Wide Range of Caliber: DN100-to-DN900 diameter range

2. High Switching Speed: 0.3 to 0.8 second/time

3. Sealing Structure: lip-shape sealing structure with two-way zero leakage and self-repairing after wearing

4. Sealing Materials: reinforced PTFE material with high wearing resistance

5. Power Drive: driven by low-pressure, clean and oil-free instrument gas, which is relatively easy to obtain.

6. Maintenance: The valve is small in size, light in weight, easy to maintain. The maintenance cost is lower than that of other types of valves.