DYC-JQ series electro-magnetic pressure difference gas valve is a special valve installed in the inlet of mechanical vacuum pump and open & close simultaneously.
When the pump stops working or power supply is suddenly interrupted, the valve will depend on atmospheric and vacuum pressure on making the valve plate closes automatically, will be closed vacuum system to maintain their vacuum, and the atmosphere through the throttle valve into the pump chamber in order to avoid pump oil return to vacuum system

The applicable active medium of this valve are air, non-corrosive gas