1. Valve clearance Mach number Ma
The size of the valve clearance Mach number Ma affects the pressure loss when the gas flows through the valve, that is, affects the economy. The Mach number should be as small as possible, but it is limited by the valve installation size and lift.

2. The ratio of the spring force to the gas thrust at full opening μ
The μ value will affect the movement law of the valve plate. The movement law of the valve plate is closely related to the exhaust volume, efficiency and reliability of the compressor. In order to obtain a good valve plate movement law, a suitable μ value should be selected.

3. Valve lift H
The valve lift H is not only related to the pressure loss, but also to the speed at which the valve plate hits the lift limiter. It directly affects the service life of the valve.