What parts inside the WFB self-priming pump are damaged?
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The WFB self-priming pump could not be inspected after it was started. The disassembly is shown in the picture below. Could you please tell me the name of the damaged part inside the pump? Why can't I inspect the pump?
The suction chamber partition separates the suction chamber from the housing where the impeller functions. The diameter of the hole in the middle of the partition is about the same size as the diameter of the impeller center without blades. The partition is damaged due to erosion, and the hole in the center of the partition is enlarged. After the impeller does work on the liquid, the liquid flows back into the pump suction chamber, so the pump cannot be measured without measuring.
Sir, thank you for your advice. I would like to ask again: 1. At the entrance of the impeller, is there an "impeller mouth ring" between the impeller and the partition plate? If there is an impeller ring, is it worn out? 2. What causes the partition plate at the impeller inlet to be "washed out"? Is it related to cavitation?
The impeller is a semi-open impeller with no orifice ring at the inlet. This pump also has a closed impeller, but basically there is no orifice ring. The reason for scouring is solid particles in the liquid, corrosion of the material, cavitation of the pump, etc., which together cause damage to the pump.
Is this baffle called a tongue? What is its function? Thank you.
The tongue-shaped part of the centrifugal pump volute near the outlet is called a diaphragm. The area circled in the figure below is where the water in the volute increases energy through the impeller. With the diaphragm as the boundary, one side is a low-pressure area and the other side is a high-pressure area. The high pressure zone is converted into kinetic energy through the volute outlet. What you circled can be regarded as an anti-eddy current baffle. The area enclosed by the box on the right side of the picture is the outlet of the pump. Add a baffle here to change the direction of the liquid flow so that it can be discharged from the outlet.
The tongue-shaped part of the centrifugal pump volute near the outlet is called a diaphragm. The area circled in the figure below is where the water in the volute increases energy through the impeller. With the diaphragm as the boundary, one side is a low-pressure area and the other side is a high-pressure area. The high pressure zone is converted into kinetic energy through the volute outlet. What you circled can be regarded as an anti-eddy current baffle. The area enclosed by the box on the right side of the picture is the outlet of the pump. Add a baffle here to change the direction of the liquid flow so that it can be discharged from the outlet.
The self-control self-priming pump has a welded structure, and cavitation has formed during the self-priming process. After cavitation, the pump performance declines, so the pump cannot be measured, that is, there is no flow and lift.
This is a self-priming pump that fully considers the impact of self-priming working conditions on the equipment, as well as the inherent characteristics of the self-priming pump without seals.
Thanks to the pump repairman on the second floor for the instruction. Now I know where the tongue is. As the teacher said, "The suction chamber partition separates the suction chamber from the housing where the impeller functions. The diameter of the hole in the middle of the partition is about the same size as the diameter of the impeller center without blades. The baffle is washed out and the hole in the center of the baffle is enlarged. After the impeller does work on the liquid, the liquid flows back into the pump suction chamber, so the pump cannot measure the volume.” I also want to ask a question. If the original designed impeller suction inlet diameter is 50mm, the corresponding opening diameter of the bottom partition is 51mm. Due to the time of use, the opening of the partition plate is abraded, the opening aperture will increase, the volume loss of the volute chamber will also increase, the vacuum degree of the impeller inlet will decrease, and the suction capacity of the impeller will decrease. Ask how much the diameter of the corroded hole in the partition opening increases before the impeller loses its ability to absorb liquid. Is there a specific calculation formula?
As long as there is no serious damage to the structure, such pump failure is mainly caused by vacuum failure. Find leaks. Check for cracks. Or the liquid level is too low, try raising the liquid level.