Working Principle and Attributes: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a constant 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. They can be close to to each other and to the housing with no actual contacting, so lubrication is unnecessary while in the working housing. The carefully balanced working parts and large precision bevel wheels ensue the pump be operated stably and continuously below the ailment of high-pressure distinction. Dynamic seal portion utilizes our patent technological innovation and imported oil seals, the vibration volume of shaft around the shaft seals is managed to less than 0.02mm. A gravity valve is put in concerning the suction and exhaust part of the pump. The function with the gravity valve is as follows, when the strain difference amongst the suction and exhaust element is over the weight on the valve, the valve opens automatically, which makes the pressure difference generally continue to keep in the fixed controllable worth, the worth may be the allowable highest stress big difference to make sure the pump operate typically and to ensure in actual fact, the roots vacuum pump with overflow valve is usually a variety of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has substantially larger pace at relatively reduced inlet strain and it’s possessed overload self-protective perform. As it is a pump of dry clearance seal construction, if a specific pumping velocity price 15 and an ultimate vacuum should be obtained, it is essential to provide a reduce inlet strain for decreasing the back movement, consequently, a pump need to be backed in use, roots vacuum pump need to be started off soon just after its inlet pressure reaches a permissible worth for economization. It is permit to select distinct varieties of pump as the backing pump for factual specifications, such as oil seal pump and liquid ring vacuum pump. When pumping the gasoline containing significant volume of vapor, the liquid ring vacuum pump will be the best backing pump.