Working Principle and Features: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a frequent 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 particular relative positions. They may be close to to each other and to the housing with no actual contacting, so lubrication is unnecessary while in the doing work housing. The thoroughly balanced operating parts and higher precision bevel wheels ensue the pump be operated stably and continuously below the affliction of high-pressure distinction. Dynamic seal element utilizes our patent engineering and imported oil seals, the vibration level of shaft on the shaft seals is managed to less than 0.02mm. A gravity valve is put in involving the suction and exhaust part of the pump. The function on the gravity valve is as follows, when the strain variation among the suction and exhaust component is in excess of the fat on the valve, the valve opens instantly, which makes the pressure variation constantly retain in the fixed controllable worth, the worth will be the allowable highest stress big difference to ensure the pump perform typically and in order that in truth, the roots vacuum pump with overflow valve is often a variety of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has substantially greater speed at rather reduced inlet strain and it is possessed overload self-protective perform. As it is usually a pump of dry clearance seal development, if a particular pumping velocity price 15 and an ultimate vacuum should be obtained, it is essential to provide a lower inlet strain for decreasing the back movement, therefore, a pump have to be backed in use, roots vacuum pump really should be started off soon immediately after its inlet pressure reaches a permissible worth for economization. It is permit to select various types of pump since the backing pump for factual requirements, such as oil seal pump and liquid ring vacuum pump. When pumping the gas containing substantial level of vapor, the liquid ring vacuum pump will be the perfect backing pump.