Centrifugal Pump

Description of Centrifugal pump

Centrifugal pump is the use of impeller rotation to make the water centrifugal movement to work. Before the pump is started, the pump shell and the suction tube must be filled with water, and then the motor is started, so that the pump shaft drives the impeller and water to do high-speed rotating movement, and the water has centrifugal movement, is thrown to the outer edge of the impeller, and flows into the pressure water pipe of the pump through the flow channel of the spiral pump shell.

The basic structure of the centrifugal pump is composed of eight parts, which are: impeller, pump body, pump cover, water retaining ring, pump shaft, bearing, sealing ring, stuffing box, axial force balancing device.

Classified by number of impellers

1. single-stage pump: there is only one impeller on the pump shaft.
2. Multistage pump: there are two or more impellers on the pump shaft, then the total lift of the pump is the sum of the lift generated by n impellers.

Classified by job stress

1. Low pressure pump: pressure below 100 meters water column;
2. Medium pressure pump: the pressure is between 100~650 meters water column;
3. High pressure pump: pressure higher than 650 meters water column.

Classified by impeller suction mode

1. Unilateral water inlet pump: also called single suction pump, that is, there is only one water inlet on the impeller;
2. Double water inlet pump: also called double suction pump, that is, there is a water inlet on both sides of the impeller. Its flow rate is twice as large as the single-suction pump, and it can be approximately regarded as two single-suction pump impellers placed back-to-back together.

Classified by pump housing combination

1. Horizontal center open pump: that is, a joint is opened on the horizontal surface through the axis line.
2. Vertical bonding surface pump: that is, the bonding surface is perpendicular to the axis line.

Classified by pump shaft position

1. Horizontal pump: The pump shaft is in a horizontal position.
2. Vertical pump: The pump shaft is located in a vertical position.

Classified by impeller exit method

1. Volute pump: After the water comes out of the impeller, it goes directly into the pump housing with a spiral shape.
2. Guide vane pump: After the water comes out of the impeller, it enters the guide vane set outside it, and then enters the next stage or flows into the outlet pipe.

Classified by installation height

1. Self-filling centrifugal pump: the pump shaft is lower than the surface of the suction pool, and it does not need to be filled when starting, and can be automatically started.
2. Rifugal pump (non-self-filling centrifugal pump) : the pump shaft is higher than the surface of the suction tank. Before starting, it is necessary to fill the pump shell and suction pipe with water first, and then drive the motor, so that the impeller rotates at a high speed, the water is thrown out of the impeller by centrifugal force, and the center of the impeller forms negative pressure, the water in the suction pool enters the impeller under atmospheric pressure, and is thrown out of the impeller into the pressurized water pipe by the high-speed rotating impeller.

In addition, according to the use can also be classified, such as oil pump, water pump, condensate pump, ash pump, circulation pump and so on.

Advantages of Centrifugal pump

1. Compact construction
2. Wide range of flow and head
3. Suitable for mildly corrosive liquids
4. A variety of control options
5. Uniform flow, smooth operation, small vibration. No special damping is required for the foundation.
6. Equipment installation, maintenance and repair costs are low.