There are several types of water pumps in the top pipe according to their functions: 

1. In the mud water balance top pipe, the inlet pump needs to transport water through the pump to the front of the cutting disc of the top pipe machine and participate in cutting together with the cutting disc. 

2. The mud pump transports the soil, stone, sand, etc. cut by the cutterhead to the surface. 

3. High pressure water pump. Generally used for high-pressure flushing of disc cutters. 

4. Relay pump. Used in long-distance pipe jacking to solve the problem of decreased conveying force caused by long water pump conveying distance.