What is a centrifugal pump?

Posted by angroup on September 14, 2021

Table of Content

Centrifugal pump definition
Centrifugal pump basic structure
The working principle of centrifugal pump
Working process of centrifugal pump
Classification of centrifugal pumps
Centrifugal pump technical parameters
Centrifugal Pump Benefits

Centrifugal pump definition

Centrifugal pumps refer to pumps that rely on the centrifugal force generated when the impeller rotates to transport liquids, and the energy for impeller rotation usually comes from diesel engines or electric motors. Applicable to various industries, such as industrial applications agricultural irrigation, municipal water supply, power station circulation water supply, urban pollution treatment, etc.

Centrifugal pump basic structure

The basic components of a centrifugal pump are a high-speed rotating impeller and a fixed worm-shaped pump casing. The impeller is fastened to the pump shaft and driven by the pump shaft with the motor or diesel engine for high-speed rotation (also see centrifugal pump parts)
The impeller is the part that does work directly on the liquid in the pump and is the energy supply device of the centrifugal pump. The suction port in the center of the pump casing is connected with the suction pipeline, and the bottom of the suction pipeline is equipped with a one-way bottom valve. The discharge port at the side of the pump casing is connected to the discharge pipeline with a regulating valve.

The working principle of centrifugal pump

Centrifugal pump in the work, relying on high-speed rotation of the impeller, the liquid in the role of inertial centrifugal force gained energy to improve the pressure. Centrifugal pump in the work before the pump body and inlet pipeline must be full of liquid media, to prevent cavitation phenomenon. When the impeller rotates rapidly, the vane prompts the medium to rotate quickly, and the rotating medium flies out of the impeller under the action of centrifugal force, and the water inside the pump is thrown out after the central part of the impeller forms a vacuum area. One side constantly inhales the liquid, and the other side constantly gives a certain amount of energy to the inhaled liquid and discharges the liquid

Working process of centrifugal pump

Before starting the pump, fill the pump with the liquid to be delivered
After the pump is turned on, the pump shaft drives the impeller to rotate at a high speed to generate centrifugal force. Under this action, the liquid is thrown from the center of the impeller to the outer periphery of the impeller, the pressure increases, and flows into the pump casing at a very high speed.
Due to the continuous expansion of the flow channel in the volute pump casing, the flow rate of the liquid slows down, so that most of the kinetic energy is converted into pressure energy. Finally, the liquid flows into the discharge pipe from the discharge port with a higher static pressure
After the liquid in the pump is thrown out, a vacuum is formed in the center of the impeller. Under the action of the pressure difference between the liquid surface pressure (atmospheric pressure) and the pressure in the pump (negative pressure), the liquid enters the pump through the suction pipe to fill the gap. Where to drain the liquid

Classification of centrifugal pumps

Centrifugal pumps are classified in various ways, including by working pressure, by a number of working impellers, by way of impeller intake, etc.

According to working pressure

Low-pressure pumps: pressures below 100 m water column
Medium pressure pump: pressure between 100 and 650 m water column
High-pressure pump: pressure higher than 650 m water column

By number of working impeller

Single-stage pumps: only one impeller on the pump shaft
Multi-stage pump: There are two or more impellers on the pump shaft when the total head of the pump is the sum of the heads produced by n impellers

By impeller inlet method

Single side inlet pump: also called single suction pump, there is only one inlet on the impeller
Double-side 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 that of single suction pumps, which can be approximated as two single suction pump impellers placed back to back.

By pump shaft position

Horizontal pumps: pump shaft in a horizontal position
Vertical pump: the pump shaft is located in a vertical position

According to the medium conveyed by the centrifugal pump

Clean water pumps
Sewage pumps
Slurry pumps

By installation height

Self-priming centrifugal pump: the pump shaft is lower than the surface of the suction pool, no need to irrigate when starting, it can start automatically
Suction centrifugal pump (non-self-irrigating centrifugal pump): the pump shaft is higher than the surface of the suction pool. Before starting, it is necessary to fill the pump casing and suction pipe with water, then drive the motor to make the impeller rotate at high speed, the water is thrown out of the impeller by the centrifugal force, the negative pressure is formed in the center of the impeller, the water in the suction pool enters the impeller under the action of atmospheric pressure, and is thrown out of the impeller into the water pressure pipe by the action of the impeller rotating at high speed.

Special construction

The pipeline pump is installed as part of the pipeline without changing the pipeline
Submersible pump and motor are submerged in water as one unit
The submerged pump body is immersed in liquid

Centrifugal pump technical parameters

Pump Terms Glossary

Flow Rate
Head
Pumping liquid temperature range
System pressure
Shaft Power

Centrifugal Pump Benefits

Compact construction
Wide range of flow and head
Suitable for mildly corrosive liquids
Multiple control options
Uniform flow rate, smooth operation, and low vibration No special vibration-damping foundation is required
Low equipment installation, maintenance, and overhaul costs

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