Answer: The main function is that when the machine is in the unloaded state, the intake valve is in the closed state to ensure that a sufficient amount of air enters the compressor so that the air compressor can establish lubricating oil pressure, ensure the stable operation of the rotor and avoid surge; second, when the machine is in the unloaded state, the intake butterfly valve is closed and the pressure is released through the small hole to ensure that the single swing check valve can be closed smoothly.
