Operating Principle and Characteristics: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a continual speed within the pump housing for suction and exhaust of gas. Two rotors are supported by two bearings and synchronized by a gear, which ensures these two rotors in certain relative positions. They are close to to each other and also to the housing without having real contacting, so lubrication is needless during the working housing. The carefully balanced working components and large precision bevel wheels ensue the pump be operated stably and constantly below the ailment of high-pressure variation. Dynamic seal component employs our patent technology and imported oil seals, the vibration quantity of shaft within the shaft seals is managed to less than 0.02mm. A gravity valve is put in amongst the suction and exhaust part of the pump. The perform on the gravity valve is as follows, when the strain difference involving the suction and exhaust aspect is more than the fat of the valve, the valve opens instantly, which tends to make the pressure big difference always hold inside a fixed controllable value, the worth is definitely the allowable highest pressure big difference to make sure the pump operate normally and to ensure in reality, the roots vacuum pump with overflow valve can be a kind of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has considerably larger velocity at reasonably lower inlet stress and it really is possessed overload self-protective function. Since it is usually a pump of dry clearance seal construction, if a certain pumping velocity rate 15 and an greatest vacuum have to be obtained, it really is required to supply a reduced inlet pressure for cutting down the back movement, consequently, a pump should be backed in use, roots vacuum pump really should be began soon soon after its inlet stress reaches a permissible value for economization. It really is allow to pick distinct types of pump since the backing pump for factual needs, this kind of as oil seal pump and liquid ring vacuum pump. When pumping the gasoline containing significant amount of vapor, the liquid ring vacuum pump could be the perfect backing pump.