The control switch can be set in two states:OFF and ON.In the state of ON,the vacuum level of the wall source can be adjusted by the regulator; Membrane suction regulator,the vacuum can be regulated from 0 to -90KPa(-680mmHg).The overflow protection device can safely and efficiently prevent the liquid from entering into the regulator or the pipeline. Pressure relief valve can safely and efficiently prevent the device and the patient from damaging by the pressure.