Working Principle and Characteristics: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a continuous velocity inside the pump housing for suction and exhaust of gasoline. Two rotors are supported by two bearings and synchronized by a gear, which assures these two rotors in specific relative positions. These are near to each other and to the housing devoid of real contacting, so lubrication is pointless during the doing work housing. The cautiously balanced working parts and higher precision bevel wheels ensue the pump be operated stably and continuously beneath the issue of high-pressure variation. Dynamic seal component utilizes our patent technologies and imported oil seals, the vibration level of shaft about the shaft seals is controlled to much less than 0.02mm. A gravity valve is put in in between the suction and exhaust a part of the pump. The function from the gravity valve is as follows, once the pressure difference concerning the suction and exhaust part is in excess of the bodyweight with the valve, the valve opens immediately, which helps make the stress variation always keep in the fixed controllable value, the worth would be the allowable highest pressure variation to guarantee the pump function ordinarily and to ensure actually, the roots vacuum pump with overflow valve is actually a form of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has substantially increased pace at relatively reduced inlet stress and it is possessed overload self-protective perform. Because it is often a pump of dry clearance seal development, if a certain pumping velocity rate 15 and an greatest vacuum have to be obtained, it’s needed to supply a reduced inlet stress for decreasing the back movement, hence, a pump must be backed in use, roots vacuum pump must be started out quickly just after its inlet strain reaches a permissible value for economization. It really is permit to select diverse varieties of pump because the backing pump for factual requirements, such as oil seal pump and liquid ring vacuum pump. When pumping the gasoline containing big quantity of vapor, the liquid ring vacuum pump is definitely the suitable backing pump.