Centrifugal pump is an inseparable part in washers, dishwashers and automobile engines and is also used to keep swimming pools clean and even to fuel our vehicles when we fill up our cars with gas at gas stations. In a word, centrifugal pump has a very close relationship with our lives. What’s more, they are also widely used in a lot of industrial applications. So getting a better knowledge of how the derrick screen functions might help us a lot in our daily life. The operating principle of the centrifugal pump is to make the use of a centrifugal impeller to make the water do some centrifugal movement. Before the pump starts, it is necessary to make the pump casing and suction tube filled with water. Then the motor starts and the pump spindle drives the impeller and water to do high speed rotation. Then the water makes centrifugal motion and is left to the outer edge of the impeller. Therefore, the water flaws from the volute pump shell into the pump pressure. From the operating principle of the centrifugal pump, we know that the centrifugal pump functions with all its components working together.
In order to have a better understanding of how centrifugal pump functions, having a look of the function of each part of the centrifugal pump might help a lot and make the matter easier to understand. We take the 518 centrifuge as an example, because similar types of centrifugal pumps have similar structures and functions if not the same. The 518 centrifuge consists of six basic parts. They are impeller, pump body, pump shaft, bearing, seal ring and stuffing box. Impeller is the core part of a centrifugal pump and the blades plays the major role in impeller. Usually, the inside and outside surface of the impeller is smooth to reduce friction loss of water. Pump body, which is also called the pump shell, is the main body of the pump. It functions as the support force for the whole 518 centrifuge. The role of pump shaft is to connect with motor by the coupling and pass the torque of the motor to the impeller. Therefore, it is a major part of the mechanical energy transfer. Sliding bearing uses a kind of transparent oil as lubricant to make a level line for gas addition. Sealing ring is used to keep the gas from leaking, so it is also called the minus leakage ring. Stuffing box is mainly composed of filler, seal ring, filler tube, packing gland and water tubes. The role of the stuffing box is mainly to seal the gap between pump casing and pump shaft, stopping the water in the pump flowing outside and the outside air into the pump, therefore, always keeping the pump vacuum.