Operating Principle and Options: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a frequent speed inside 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 certain relative positions. They may be close to to one another and to the housing without the need of actual contacting, so lubrication is pointless while in the functioning housing. The meticulously balanced operating parts and higher precision bevel wheels ensue the pump be operated stably and continuously below the situation of high-pressure big difference. Dynamic seal portion makes use of our patent engineering and imported oil seals, the vibration volume of shaft around the shaft seals is controlled to significantly less than 0.02mm. A gravity valve is set up amongst the suction and exhaust a part of the pump. The function on the gravity valve is as follows, once the pressure distinction involving the suction and exhaust element is over the bodyweight of the valve, the valve opens automatically, which helps make the pressure big difference often preserve in the fixed controllable value, the worth would be the allowable highest strain variation to make sure the pump get the job done usually and so that in actual fact, the roots vacuum pump with overflow valve is really a sort of overload self-protective pump. Series SYF roots vacuum pump with overflow valve has considerably higher velocity at relatively reduced inlet stress and it is possessed overload self-protective function. As it is a pump of dry clearance seal construction, if a particular pumping speed fee 15 and an greatest vacuum should be obtained, it is actually necessary to supply a reduced inlet strain for decreasing the back movement, for that reason, a pump needs to be backed in use, roots vacuum pump need to be begun quickly following its inlet stress reaches a permissible value for economization. It is allow to pick various varieties of pump since the backing pump for factual requirements, such as oil seal pump and liquid ring vacuum pump. When pumping the fuel containing large level of vapor, the liquid ring vacuum pump would be the ideal backing pump.