Composite Coating Project
Weir Split Casing Raw Water Pump.
Step 1 : The condition of the pump had eroded badly on the impeller & the wear rings due to high pH in the water. (pH 2).
Step 2 : After grit blasting to S.A 2.5 Swedish Std @ 75-100 microns profile, a strong evidence of severely damaged area at around wear rings and the cut water, as shown in picture.
Step 3 : Even the Bronze impeller is not spared from the erosion attack.
Step 4 : By using polymer composite (paste type) to rebuild holed area. Thus no heat or fire is applied to further damage the metal properties!
Step 5 : By using polymer composite to rebuild (paste type) and protect with 2 coats of ceramic polymer composites (liquid type) with a total thickness of 500 – 750 microns dft. The polymer composites are 100% solids therefore it won’t shrink.
Step 6 : The wear ring areas & the Cut Water were rebuilt by paste and protected by the liquid polymer composites.
Step 7 : All coating job are done in an air-conditioned room to minimize dust before applying the polymer composites to ensure quality bonding of the coatings. To prevent a pin-hole miss, the polymer composites comes in two colors.
Step 8 : Finishing coat with a blue color. Once fully cured, it will be sent to do dynamic balancing on a Schenck balancer.
Step 9 : The wear ring area was fully rebuilt by polymer composites on a cast iron material. No worries of distortion as like conventional welding process!
Step 10 : After dynamic balancing, all components are re-assembled into place. Care in installing the wear rings & shaft into casing is very important.
Step 11 : Even the Bronze impeller is not spared from the erosion attack.