The shape structure and working principle of the axial flow pump are different from those of the centrifugal pump, and its performance is also very different. In actual work, it is necessary to strictly distinguish, and use different methods to guide production practice and solve production problems. Of course, the scope of use is different, the differences are as follows:
1. Liquid flow (water) flows out in different directions after passing through the impeller:
A. Centrifugal pump: radial flow under the action of centrifugal force.
B. The axial flow pump maintains axial flow (parallel to the center of rotation of the impeller).
2. The specific speed is different:
The specific speed of the centrifugal pump is below 300, and the specific speed of the axial flow pump is greater than 500.
3. Different working principles:
A. Centrifugal pumps are generally driven by electric motors. Before starting the pump, the pump body and the suction pipe are filled with liquid. When the impeller rotates at high speed, the impeller drives the liquid between the blades to rotate together. Due to the centrifugal force, the liquid is thrown from the center of the impeller to the outer edge of the impeller (the flow rate can be increased to 15-25m/s), and the kinetic energy also increases. When the liquid enters the pump casing, as the flow channel in the volute-shaped pump casing gradually expands, the flow rate of the liquid gradually decreases, and part of the kinetic energy is converted into static pressure energy, so the liquid flows out along the discharge port at a higher pressure. At the same time, a certain vacuum is formed at the center of the impeller due to the liquid being thrown out, and the pressure Pa at the liquid level is higher than that at the center of the impeller. Therefore, the liquid sucked into the pipeline enters the pump under the action of the pressure difference. The impeller keeps rotating, and the liquid is continuously sucked and pressed out. Because centrifugal pumps are able to transport liquids mainly rely on centrifugal force, they are called centrifugal pumps.
B. The axial flow pump uses the thrust (lift) generated by the rotation of the impeller on the water body to work. It is a large flow and low head water pump.
The working principle of the axial flow pump The working principle of the axial flow pump is different from that of the centrifugal pump. It mainly uses the thrust generated by the high-speed rotation of the impeller to lift water. The lift generated by the blades of the axial flow pump against the water can push the water from below to above.
The blades of the axial flow pump are generally immersed in the pool of the water source. Due to the high-speed rotation of the impeller, under the action of the lift generated by the blades, the water is continuously pushed upward, causing the water to flow out along the outlet pipe. The impeller rotates continuously, and the water is continuously pressed to a high place.
The work of the axial flow pump is based on the lift theory in aerodynamics. When the impeller rotates at a high speed, the liquid particles in the pump body will be affected by the axial lift force from the impeller, causing the water flow to flow in the axial direction.
4. The performance curve of the pump is different:
A. The centrifugal pump has a small flow and a high lift. When in use, it must not exceed the rated flow of the pump. The outlet valve can be used to adjust the flow so that the pump will not be overloaded. To start by closing the valve, the power is relatively small at this time and the motor is not easily burned.
B. Axial flow pump has large flow and low lift. The outlet valve cannot be used to adjust the flow. It cannot exceed the rated range in use. It is not advisable to start by closing the valve. When the axial flow pump is started, the outlet valve should be opened. At this time, the power is relatively small and the motor does not Easily burned.
5. The structure of the pump is also different:
Centrifugal pumps generally have a volute. The axial flow pump looks like a water pipe, and the diameter of the pump casing is about the same as the diameter of the suction port.
