Working Principle and Options: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a continual velocity inside the pump housing for suction and exhaust of gas. Two rotors are supported by two bearings and synchronized by a gear, which guarantees these two rotors in certain relative positions. They can be near to one another and also to the housing without having real contacting, so lubrication is unnecessary within the operating housing. The very carefully balanced working parts and high precision bevel wheels ensue the pump be operated stably and constantly beneath the situation of high-pressure distinction. Dynamic seal portion employs our patent engineering and imported oil seals, the vibration quantity of shaft around the shaft seals is controlled to less than 0.02mm. A gravity valve is installed concerning the suction and exhaust part of the pump. The function on the gravity valve is as follows, when the pressure distinction in between the suction and exhaust component is over the bodyweight of the valve, the valve opens instantly, which helps make the pressure difference often maintain in a fixed controllable value, the worth will be the allowable highest pressure difference to ensure the pump operate commonly and to ensure in reality, the roots vacuum pump with overflow valve is usually a sort of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has considerably greater pace at fairly lower inlet pressure and it really is possessed overload self-protective function. As it can be a pump of dry clearance seal development, if a specific pumping velocity fee 15 and an ultimate vacuum have to be obtained, it can be needed to provide a reduce inlet pressure for minimizing the back movement, for that reason, a pump need to be backed in use, roots vacuum pump should be began quickly soon after its inlet stress reaches a permissible worth for economization. It really is allow to select different sorts of pump since the backing pump for factual needs, such as oil seal pump and liquid ring vacuum pump. When pumping the gasoline containing massive level of vapor, the liquid ring vacuum pump may be the suitable backing pump.