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The Working Principle and Basic Structure of Self-priming Centrifugal Pump

Centrifugal pump with self priming working principle

Centrifugal pump is designed according to the principle of centrifugal force. The impeller blades rotating at high speed drive the water to rotate and throw out the water so as to achieve the conveying purpose. There are many kinds of centrifugal pumps, which can be divided into civil and industrial pumps from the use; clear water pumps, impurity pumps, corrosion resistant pumps, etc. from the conveying medium. buy industrial pumps from All Pump Machinery factory.

Centrifugal is actually the performance of the inertia of the object, such as the water droplets on the umbrella, when the umbrella slowly rotates, the water droplets will follow the umbrella rotation, this is because the friction between the umbrella and the water droplets as the centripetal force to the water droplets.

But if the umbrella rotation is accelerated, the friction force is not enough to make the water drop to do circular motion, then the water drop will be separated from the umbrella to the outer edge of the movement, just like a rope pulling a stone to do circular motion, if the speed is too fast, the rope will break, the stone will fly out. This is the so-called centrifugal.


Centrifugal pump with self priming basic structure

The basic structure of centrifugal pump is composed of six parts: impeller, pump body, pump shaft, bearing, sealing ring and stuffing box.

1, the impeller is the core part of the centrifugal pump, it is high speed output force, the impeller on the blade and play a major role, the impeller in the assembly before the static balance test. The inner and outer surface of the impeller is required to be smooth to reduce the friction loss of water flow.

2、Self priming centrifugal pump pump body is also called pump casing, it is the main body of the pump. It plays the role of supporting and fixing, and is connected with the bracket for installing bearings.

3、Self priming centrifugal pump pump shaft is connected to the motor by coupling, and the torque of the motor is transmitted to the impeller, so it is the main part to transmit mechanical energy.

4、The bearing is a component set on the pump shaft to support the pump shaft, there are two kinds of rolling bearings and sliding bearings. Rolling bearings use butter as lubricant, the oil should be appropriate, generally 2/3 to 3/4 of the volume, too much will be hot, too little and there is a loud noise and heat. The use of transparent oil as a lubricant, refueling to the oil level line. Too much oil to seep out along the pump shaft and splash, too little bearing to overheat and burn out cause accidents. During the operation of the pump, the maximum temperature of the bearing is 85℃, and the general operation is about 60℃, if it is high, we should find the reason (whether there are impurities, whether the oil is black, whether water is in) and deal with it in time.

5, sealing ring is also known as leakage reduction ring. The gap between the impeller inlet and the pump casing will cause the water in the high-pressure area of the pump to flow to the low-pressure area through this gap, affecting the water output of the self priming centrifugal pump and reducing efficiency. The gap is too small will cause the impeller and pump casing friction wear. In order to increase the return resistance to reduce internal leakage and extend the service life of the impeller and pump casing, the inner edge of the pump casing and the outer edge of the impeller are combined with a sealing ring, and the gap between the seal is kept between 0.25 and 1.10mm.

6、The stuffing box is mainly composed of packing, water seal ring, packing cylinder, packing gland and water seal tube. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft to prevent the water inside the pump from flowing outside and to prevent the air outside from entering the pump, always keeping the vacuum inside the pump. When the pump shaft and the packing friction generates heat, it is necessary to rely on the water seal tube to inject water into the water seal ring to make the packing cool down and keep the normal operation of the pump. Therefore, we should pay special attention to the checking of the stuffing box during the operation tour of the pump. In about 600 hours of operation, the packing should be replaced.

7, axial force balancing device in the operation of centrifugal pumps, because the liquid is at low pressure into the impeller, and at high pressure out, so that the pressure on both sides of the impeller is not equal, resulting in the direction of the inlet axial thrust, will cause the rotor axial movement, wear and vibration, so the axial thrust bearing should be set in order to balance the axial force.