Working Principle and Attributes: 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 fuel. Two rotors are supported by two bearings and synchronized by a gear, which ensures these two rotors in particular relative positions. They’re close to to one another and also to the housing with no actual contacting, so lubrication is unnecessary while in the working housing. The very carefully balanced operating components and substantial precision bevel wheels ensue the pump be operated stably and continuously underneath the condition of high-pressure difference. Dynamic seal component uses our patent technologies and imported oil seals, the vibration amount of shaft within the shaft seals is controlled to much less than 0.02mm. A gravity valve is set up concerning the suction and exhaust part of the pump. The function in the gravity valve is as follows, once the pressure variation amongst the suction and exhaust element is over the excess weight with the valve, the valve opens instantly, which helps make the pressure difference always keep in a fixed controllable worth, the value will be the allowable highest stress difference to ensure the pump function normally and so that in fact, 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 speed at relatively reduce inlet pressure and it is possessed overload self-protective function. Since it is really a pump of dry clearance seal construction, if a specific pumping velocity price 15 and an greatest vacuum should be obtained, it really is important to supply a decrease inlet pressure for lowering the back flow, consequently, a pump must be backed in use, roots vacuum pump needs to be started out quickly right after its inlet strain reaches a permissible worth for economization. It can be allow to select various types of pump since the backing pump for factual prerequisites, such as oil seal pump and liquid ring vacuum pump. When pumping the gas containing massive volume of vapor, the liquid ring vacuum pump may be the excellent backing pump.