vent vacuum valves

installed on the top of the oil tank to ensure the oil tank's certain inside pressure. When the oil into the tank,tank pressure increased more step,the valve automatically open up so that the tank pressure to lower pressure ,the valves automatically closed out ,when  the tank  discharge oil ,the tank vacuum more higer ,intake valve automatically open so reduce tank vacuum pressure,air inlet valve to shut down automatically

Material :

Body:SS

Seal: NBR