The maintenance method of stainless steel centrifugal pump impeller is as follows:
The impeller of the stainless steel centrifugal pump may suffer certain degrees of damage. If any of the following conditions occur to the impeller, the impeller should be replaced:
- There are cracks on the impeller surface.
- Many holes are formed on the impeller surface due to corrosion, erosion or cavitation.
- Due to the flushing effect, both the outer cover and the blades of the impeller gradually become thinner, which in turn affects the mechanical strength of the impeller.
- The impeller mouth and hub have serious eccentric wear and are not worth repairing.
If the impeller is not seriously corroded or has few sand holes, it can be repaired by repair welding. The repair welding method is to clean the welding part before welding to remove oil, rust, oxide scale, etc. It can be preheated either locally or as a whole to a temperature range of 250°C to 450°C. Welding powder usually uses powder 301, welding wire usually uses welding wire 224 silicon brass welding wire, gas welding flame uses light oxidizing flame or neutral flame, and the crimping method is generally adopted during the welding operation to reduce the amount of weld metal.
To prevent overheating and improve the formation quality of welds, during work, try to avoid direct contact between the high – temperature flame core and the molten pool metal to avoid the formation of pores in the weld metal. After welding, insulate the welded impeller and let it cool down slowly to relieve stress and improve its performance. After cooling, it can be machined.
When the grooves or eccentric wear caused by wear of the single – ring sealing ring and wheel hub are not serious, they can be polished with sandpaper, and can also be polished by car if the thickness allows. Or use metal spraying to restore to the original size. If there are no serious grooves or eccentric wear on the sealing end of the double – ring inner sealing ring, it can also be polished with sandpaper, and can also be polished by car if the thickness allows. If the wear or eccentric wear is serious, please replace the new inner ring.
New or repaired impellers should be subjected to static balancing tests. The impeller is balanced by scraping the impeller surface to adjust the weight distribution. After the test, the impeller is placed on a milling machine to remove the heavy chips, such as the clamping objects that were used during the milling of the heavier side and the balancing test of the lighter side. However, the thickness of the impeller cover after milling cannot exceed 1/3 of the thickness of the impeller cover. It is permitted to cut the impeller cover into two parts, the front cover and the rear cover. The cutting traces on the cutting part must transition smoothly with the disc of the cover.
The above is an introduction to the maintenance methods of stainless steel centrifugal pump impellers. Thank you for reading.