Operating Principle and Options: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a continuous pace within the pump housing for suction and exhaust of gas. Two rotors are supported by two bearings and synchronized by a gear, which assures these two rotors in sure relative positions. They’re close to to each other and to the housing without real contacting, so lubrication is unnecessary while in the functioning housing. The carefully balanced operating components and high precision bevel wheels ensue the pump be operated stably and continuously under the problem of high-pressure variation. Dynamic seal component employs our patent technology and imported oil seals, the vibration volume of shaft around the shaft seals is managed to much less than 0.02mm. A gravity valve is installed in between the suction and exhaust part of the pump. The function on the gravity valve is as follows, once the pressure distinction in between the suction and exhaust element is in excess of the fat in the valve, the valve opens immediately, which makes the pressure big difference generally hold in a fixed controllable value, the value is the allowable highest pressure variation to guarantee the pump work typically and to ensure in actual fact, the roots vacuum pump with overflow valve is really a kind of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has substantially increased pace at rather reduced inlet stress and it’s possessed overload self-protective perform. Since it is a pump of dry clearance seal development, if a certain pumping pace rate 15 and an ultimate vacuum should be obtained, it is actually essential to provide a decrease inlet stress for minimizing the back flow, thus, a pump must be backed in use, roots vacuum pump needs to be started soon just after its inlet pressure reaches a permissible value for economization. It can be permit to pick unique types of pump since the backing pump for factual specifications, such as oil seal pump and liquid ring vacuum pump. When pumping the gasoline containing massive volume of vapor, the liquid ring vacuum pump will be the suitable backing pump.