Centrifugal pump impeller, do you know these 5 repair methods?

Centrifugal pump impeller, do you know these 5 repair methods?

The centrifugal pump will wear and corrode gradually due to the sediment, the erosion of the water flow and the corrosion of the medium. The surface of the blade often forms grooves or streaks, or is damaged by cavitation, and the leaves have honeycomb-like holes and even perforations. If the blade is cast with stomata, blisters or slag inclusions, the surface will be prone to stomata or even cracks after running.

Common repair methods:

1, copper wire repair method
For pinhole-shaped cavitation, as long as the holes are not connected into a piece, the pinhole can be punched with a copper wire, and the trowel can be used to smear. Before processing, the surface of the blade should be cleaned with rust and dirt, then the oxygen in the pores should be blown off with the oxygen-acetylene flame, and then the appropriate thickness of the copper wire is filled into the hole, and the copper is tapped with a pointed hammer. The wire is squeezed, squeezed into the hole, and finally flattened with a file.

2, gas welding repair method
The impeller is placed on a charcoal fire and heated to 400-500 ° C. The tin is hanged at the repaired joint, and then the brass filament is melted into the groove or hole to be repaired with an oxygen-acetylene flame. After the welding, the charcoal fire is removed and the asbestos is removed. The board is covered with insulation to allow the blades to cool slowly to avoid cracking. After welding, the boring tool is used to finish the machining according to the original contour.

3, accelerated steel repair method
Quick-formed steel is a cement-like adhesive repair agent before curing. It has high strength, high hardness, no shrinkage and no rust after curing. It is suitable for filling pores, cracks, blisters, etc. in steel, iron and other metal materials. Repaired with a strong bonding effect. Before repairing, clean the rough rust and dirt around the repaired area and roughen it.

Take out the colloid in the plastic tube of the quick-form steel, and quickly and fully smash the two different colors of the material in the inner core and the outer skin (about 1 to 2 minutes) to achieve the heat and softness (public number: pump housekeeper). Before the colloidal steel colloid is to be solidified, it is firmly adhered to the repairing place, and is compacted with force (hand or tool) multiple times during the solidification process of the colloid to enhance the adhesion of the adhesive to the blade. After the fusible steel is hardened, it is flattened with a file.

4, epoxy resin repair method
According to the mixing ratio and order, take appropriate amount of epoxy resin, ethylenediamine, dibutyl phthalate and acetone in a glassware and mix well. Pay attention to the viscosity of the adhesive when mixing, and add the amount of acetone in an appropriate amount. The prepared epoxy resin is preferably used up within 20-30 minutes. Use a wool brush to pick up the epoxy resin, brush the surface of the blade with the blisters and pores. When brushing, use a sharp cone to gently squeeze out the blisters and the bubbles in the middle of the pores. Apply as much as possible and gently scrape with a scraper. real.

After the epoxy resin is cured for 1-2 hours, brush it again for 2 to 3 times. When painting the last time, be sure to make the surface of the blade smooth and smooth. After the painting is finished, the impeller is placed in an environment of 20-30 ° C and a relatively low relative humidity, and is slowly maintained for 48 hours. After the epoxy resin is completely cured, the contour of the impeller and the protrusion on the surface layer are trimmed with a file or a sander.

5, surfacing repair method
Before surfacing, grind the cavitation part with a grinder, and clean the surface of the rust and debris until the bright metal body is exposed, so that the surfacing layer and the blade are more firmly combined. After cleaning, the impeller is placed in a charcoal fire for preheating. Use the same electrode or stainless steel electrode as the blade material, without peeling, damage, keep dry, remove moisture, so as to avoid air holes in the weld.

When surfacing, it is necessary to adopt round-trip welding, or stratified cross-welding can be adopted, and the amount of welding should be less at each time to prevent the blade from being concentrated by heat and causing stress deformation. After repair welding, the blade is trimmed with a sander. The repaired impeller must be subjected to a static balance test. In order to prevent the impeller from rotating at a high speed, the centrifugal force is generated due to the imbalance of the additional weight to cause the water pump to vibrate.

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Post time: Jun-12-2019

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