Applications & Features： Vacuum indispensable control component of the system, it install on oil seal mechanical air inlet office of pump, When the pump suddenly had a power failure, stopped movesing and rotates because of the need of work, this pump utilized the atmospheric pressure to make the core of the valve drop automatically, By and passway more in vacuum, enlarge to pump angry at the same time , prevent mechanical pump oil from return to the vacuum system, Play a protecting the vacuum systematically after arriving role, help the mechanical pump to be started again.