Operating Principle and Characteristics: The series SYF roots vacuum pump is with overflow valve. The figure-of-eight rotors are counter-rotating at a continual speed within 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 selected relative positions. They are really near to one another and also to the housing without real contacting, so lubrication is pointless in the operating housing. The very carefully balanced working components and substantial precision bevel wheels ensue the pump be operated stably and constantly underneath the situation of high-pressure variation. Dynamic seal aspect employs our patent technology and imported oil seals, the vibration amount of shaft about the shaft seals is controlled to much less than 0.02mm. A gravity valve is set up in between the suction and exhaust a part of the pump. The perform of the gravity valve is as follows, once the pressure distinction concerning the suction and exhaust aspect is more than the excess weight of the valve, the valve opens immediately, which helps make the strain distinction always maintain inside a fixed controllable value, the value could be the allowable highest strain difference to be sure the pump do the job ordinarily and so that actually, 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 considerably increased velocity at comparatively lower inlet pressure and it truly is possessed overload self-protective function. Because it is actually a pump of dry clearance seal building, if a certain pumping pace fee 15 and an greatest vacuum have to be obtained, it truly is needed to supply a reduced inlet pressure for minimizing the back flow, for that reason, a pump must be backed in use, roots vacuum pump ought to be began quickly following its inlet stress reaches a permissible value for economization. It truly is allow to pick unique kinds of pump because the backing pump for factual demands, this kind of as oil seal pump and liquid ring vacuum pump. When pumping the fuel containing big amount of vapor, the liquid ring vacuum pump could be the great backing pump.