Multi-stage segmented centrifugal pumps will gradually wear and corrode due to the erosion of sediment, water flow and medium corrosion. The surface of the blades often forms grooves or streaks, or is damaged by cavitation, and the blades appear honeycomb holes. , And even perforation. If the blade is cast with pores, sand holes or slag inclusions, pores and even cracks are prone to appear on the surface after operation. There are many ways to repair the impeller of multi-stage segmented centrifugal pumps. There are many ways to repair the impeller, such as ARC polymer composite coating, powder spraying (welding), epoxy resin coating, and rubber and nylon composites. Material repair, etc., as well as the use of stainless steel inlay and surfacing.
Multi-stage segmented centrifugal pumps are commonly used to repair impeller wear and corrosion:
1. Copper wire repair method
For pinhole-like cavitation, as long as the holes are not connected to form a piece, the pinhole can be punched with red copper wire and filed with a file. Before treatment, use a polisher to remove the rust and dirt on the surface of the blade, and then use an oxygen-acetylene flame to blow away the impurities in the air hole, and then fill the hole with a copper wire of appropriate thickness, and at the same time use a sharp hand hammer to knock the copper The wire is squeezed and squeezed into the hole, and finally filed with a file.
2. Gas welding repair method
Put the impeller on a charcoal fire and heat it to 400-500℃, hang tin in the repair welding place, and then use an oxygen-acetylene flame to melt the brass wire into the groove or hole that needs to be repaired. After the welding is completed, remove the charcoal fire and use asbestos The board is covered and insulated, allowing the blades to cool slowly to avoid cracks. After welding repair, use a file to process and trim according to the original contour line.
3. Quick steel repair method
Rapid steel is a cement-like adhesive repair agent before curing. After curing, it has high strength, high hardness, no shrinkage, and no rust. It is suitable for filling and filling pores, cracks, blisters, etc. of metal materials such as steel and iron. Repair, has a strong bonding effect. Before repairing, clean up and roughen the rust and dirt around the area to be repaired. Take out the colloid in the quick steel plastic tube, and quickly and fully knead the two different colors of the inner core and outer skin of the colloid into one color (about 1 to 2 minutes) by hand to achieve heat and softness. Before the quick-forming steel colloid is solidified, it is firmly adhered to the repaired area, and it is compacted with force (hand or tool) several times during the colloid curing process to enhance the adhesion of the glue to the blade. After the quick steel is hardened, use a file to file it.
4. Epoxy repair method
Take appropriate amount of epoxy resin, ethylenediamine, dibutyl phthalate, and acetone in the glassware according to the mixing ratio and order, mix and mix well. Pay attention to the viscosity of the adhesive when stirring, and add an appropriate amount of acetone. The prepared epoxy resin should be used up within 20-30min. Dip the epoxy resin with a wool brush and paint the blisters and pores on the surface of the blades. When brushing, use a pointed cone to gently squeeze out the bubbles in the blisters and pores. Try to apply evenly and firmly, and at the same time use a scraper to gently scrape and press. real. After the epoxy resin is cured for 1-2 hours, brush it for 2 to 3 times. When painting the last time, make sure to make the surface of the blade smooth and smooth. After painting, put the impeller in an environment of 20-30℃ and low relative humidity for 48h slowly. After the epoxy resin is completely cured, use a file or a polisher to trim the outline of the impeller and the protrusions on the surface layer.
5. Surfacing repair method
Before surfacing welding, use a grinder to grind the cavitation parts to clean up the rust and debris on the surface until the shiny metal body is exposed, so that the surfacing layer and the blade are more firmly bonded. After cleaning, put the impeller into a charcoal fire for preheating. Use welding rods or stainless steel rods with the same material as the blades, or they must not peel or break, keep them dry, and remove moisture to avoid porosity during surfacing. When surfacing welding, it is necessary to adopt back-and-forth welding or layered cross pressure welding. The amount of surfacing should be small each time to prevent the blade from being concentrated by heat and causing stress and deformation. After repair welding, the blade is trimmed with a polisher. The repaired impeller must undergo a static balance test. In order to prevent the impeller from rotating at high speed, the centrifugal force caused by the imbalance of the additional weight will cause the pump to vibrate.
