Water pump generates centrifugal force or thrust through the rotation of impeller, forming pressure difference to realize liquid transportation
The working principle of water pump is mainly based on mechanical energy to transport liquid from low to high or far away, and its core is to generate pressure difference through the rotation of impeller. According to different types, the specific principles can be divided into the following categories:
1. Centrifugal pump (most common type)
Centrifugal force action
Before starting, it needs to be filled with water. When the impeller rotates at high speed, the water is thrown around under the action of centrifugal force, forming a high-pressure area and pressing into the outlet pipe.
The center of the impeller forms a vacuum low-pressure area due to the liquid being thrown out, and the external liquid is sucked in through the suction pipe under the action of atmospheric pressure to achieve continuous transportation.
Key features
The inlet and outlet water flow directions are 90° to each other, the head is high but the water suction height is limited (usually <10 meters).
It needs to be strictly sealed to prevent air leakage, otherwise a vacuum cannot be formed.
2. Axial flow pump
Thrust-dominated: The impeller rotates to generate lift, pushing water from the bottom to the top along the axial direction, suitable for large flow and low head scenarios (such as farmland irrigation and drainage).
No need to irrigate: The blades are immersed in water, and it is easy to start.
3. Mixed flow pump
Comprehensive principle: Combining centrifugal force and thrust, the water flow direction is at a certain angle to the impeller axis, and the performance is between the centrifugal pump and the axial flow pump.
4. Other types
Positive displacement pump (such as plunger pump, gear pump)
The liquid is squeezed through the periodic change of the working chamber volume to directly increase the pressure energy.
Self-priming pump
Special structures (such as air-water separation chamber) achieve self-priming, without the need to irrigate every time it is started, but the efficiency is slightly lower.
Jet pump
Use high-speed jets to irrigate fluids and transfer energy through momentum exchange.
Summary: The core of the water pump is to change the liquid pressure through mechanical energy (such as impeller rotation or volume change) to form a pressure difference to achieve transportation. When selecting, you need to match the type according to the flow rate, head and medium characteristics. For example, centrifugal pumps are suitable for medium head, and axial flow pumps are suitable for large flow and low head scenarios.