The pump body is equipped with a safety valve. When the discharge pressure exceeds the specified pressure, the conveying liquid can automatically open the safety valve to return the high pressure liquid to the suction pipe.
The internal gear pump is composed of a pair of intermeshing internal gears and a crescent member, a pump casing, and the like therebetween. The function of the crescent is to separate the suction and discharge chambers. When the driving gear rotates, a partial vacuum is formed at the place where the gear is disengaged, and the liquid is sucked into the pump to fill the teeth of the suction chamber, and then enters the discharge chamber along two sides of the inner and outer sides of the crescent. Where the teeth enter the mesh, the liquid present between the teeth is squeezed and fed into the discharge tube.
In addition to the characteristics of self-priming capacity, flow rate and discharge pressure, the gear pump has no suction valve and discharge valve on the pump casing. It has the characteristics of simple structure, uniform flow and reliable operation, but low efficiency, large noise and vibration, and easy wear. It is used to transport non-corrosive, solid-free particles and lubricating oils. The temperature is generally not more than 70 °C, such as lubricating oil, edible vegetable oil and so on. The general flow range is 0.045~30ms/h, the pressure range is 0.7-20MPa, and the working speed is 1200-4000r/min.
