Common problems and solutions for sewage pump impellers

1. Cavitation

1. Failure manifestations: improper design; installation location too high; improper material selection, etc.

2. Treatment methods: lower the installation position; change the material to be more resistant to cavitation; redesign the pump type, etc.

2. Casting defects

1. Failure manifestations: flow channels are mixed; fleshy; not smooth; trachoma; cracks; shrinkage porosity, etc.

2. Treatment method: Grinding, repair welding and other methods can be carried out according to the actual situation. If the problem is serious, it needs to be scrapped and recast.

3. Abrasion

1. Failure manifestation: The picture shows a process pump impeller cast from gray cast iron material that was worn by water containing a small amount of cement foam within 5 years. The abrasion problem is more caused by improper material selection by the designer or improper pump type selection. , or the process medium is contaminated.

2. Treatment method: change the impeller material; change the design plan, change the pump type; check the process medium.

4. Mouth ringing

1. Failure manifestations: The design gap is too small; the hardness difference between the front and rear mouth rings is less than 50HBW; there are solid particles in the mouth ring gap; the mouth ring is deformed, etc.

2. Treatment methods: increase the design gap; replace the mouth ring material; check the process medium; replace the mouth ring with a new one, etc.

5. Corrosion

1. Failure manifestation: Improper material selection.

2. Treatment method: replace the impeller with a new one, using corrosion-resistant and wear-resistant materials; coating the impeller’s corrosion-resistant layer; spraying the impeller’s corrosion-resistant layer.

6. Fracture

1. Failure manifestations: caused by cavitation, corrosion, and abrasion; caused by poor quality of castings; caused by water hammer.

2. Treatment method: Replace the impeller with a new one.

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