Understanding centrifugal pump
CENTRIFUGAL PUMP WORKING PRINCIPLES
Usually a centrifugal pump is driven by a motor. However some large centrifugal pumps are driven by turbines. Power from the motor is given to the pump shaft to rotate the impeller attached to the shaft. The liquid in the impeller will also rotate due to the impetus of the blades. Because the centrifugal force arises, the liquid flows from the center of the impeller out through the channel between the blades and leaves the impeller at high speed. The liquid that comes out of the impeller at high speed will then come out through a channel whose cross section is getting bigger (volute/diffuser) so that there is a change from velocity head to pressure head. Therefore, the liquid coming out of the pump flange has a larger total head.
The main components of a centrifugal pump consist of:
a. Shaft is a device that is used to transmit the rotary moment of the drive as long as the pump is in operating condition, this component also functions as an impeller holder and other moving parts.
b. Impeller is a device that functions to convert from mechanical energy to the pump into velocity energy in the fluid that is pumped continuously
c. Shaft sleeve serves to protect the shaft from erosion, corrosion and wear on the stuffing box. this component can be as an internal bearing, leakage joint and distance sleeve.
d. Wearing ring, this component is mounted on the casing (wearing ring casing) and impeller (wearing ring impeller). The main function of this component is to minimize leakage due to the gap between the casing and the impeller.
Basically the pump is used to accelerate the flow rate of the fluid which is generally liquid. However, in a centrifugal pump, the process of accelerating the fluid flow rate is carried out by utilizing the centrifugal force originating from the impeller which is rotated using a motor or dynamo. There are several types of impellers, including open, semi-open, and closed. When the impeller rotates in the housing or pump casing (casing), physically the impeller’s kinetic energy will cause a pressure change in the pump casing so that the liquid will enter through the suction pipe and be removed through the delivery pipe.