Why is it necessary to add water to a rural well first when it is pressurized?

Water is used to expel the air, so that a negative pressure is formed between the valve and the water, and the water is brought up under atmospheric pressure. As the water has some sealing effect, the sealing effect is improved by adding water, and the water can be pumped up very quickly, and the diversion of water serves as a seal.

A pressurized well is a tool that draws groundwater up to the surface. If you want to draw water up from the ground, you rely mainly on the diversion skin in the center of the well. It is the force of interaction between this diversion skin and the center of the well that allows the water to flow out of the well.

Expanded

Each time before shaking the water need to scoop a ladle of water back into the well, so up and down to lift the prying frame, so hoo-hoo a few times, this ladle of water will lead the water to hide the water clattering flow back. After the use of the scoop and then leave a scoop of water in the scoop, convenient for the next shake water.

With the improvement of living conditions, even in rural areas have used the tap water, this pressure well because of the decline of the natural water level and people's water quality requirements are gradually eliminated.

Baidu Encyclopedia - Pressurized Water Wells