The bottom valve has a certain positive effect on the water pump,  but it also has a negative effect on the drainage pump in the mine. The bottom valve increases the resistance of the suction pipeline, increases energy consumption, reduces the efficiency of the water pump, and decreases the suction height of the water pump.

1. During operation, poor quality of the bottom valve or the entry of debris into the bottom valve often result in poor sealing of the bottom valve, causing the water pump to be unable to supply water and unable to operate.

Due to the high corrosiveness of mine water, the bottom valve is easily damaged. During the maintenance and replacement of the bottom valve, the working conditions are harsh and the labor intensity is high.

Therefore, the current main drainage equipment in mines has mostly eliminated bottom valves and adopted vacuum pumps or jet pumps as drinking water devices for water pumps. Perform drainage.

Principle of vacuum pump start-up drainage:

Before starting the water pump,  start the vacuum pump to extract the air from the suction pipe and pump body. Due to the fact that both the upper opening of the water pump and the lower end of the suction pipe have been sealed with water, the air inside the water pump and its suction pipe is becoming increasingly thin. As the air pressure decreases, negative pressure is formed, and the water in the suction well increases with the increase of negative pressure under the action of atmospheric pressure. Gradually enter the water pump suction pipe and pump body until they are filled. At this point, turn off the vacuum pump and start the water pump to drain the water.  

Principle of Jet Start Drainage:

Jet start drainage is achieved using a jet pump, and the structure of the jet pump is shown in the figure. It mainly consists of a spray well, a suction chamber, and a mixing pipe. When high-pressure water is drawn from the drainage pipe and sprayed out at high speed from the nozzle, the high-speed jet continuously carries away the air in the suction chamber, causing the air inside the water pump and its suction pipe connected to the suction chamber to become thinner and the air pressure to become lower, forming negative pressure. Under the action of atmospheric pressure, as the negative pressure increases, the water in the suction well gradually enters the water pump suction pipe and pump body until they are fully filled. At this point, the electric motor can be started to drive the water pump for drainage.