How many gaskets should be used for an old hydraulic well with a diameter of 80 cm?

The gasket of the old hydraulic well mainly plays the role of sealing and pumping air, so the diameter of the gasket is larger than that of the hydraulic well, so the gasket with a diameter of 84 is selected.

Hydraulic well is a tool to lead groundwater underground. It is made of cast iron, with a cement-based barrier at the bottom, a water outlet at the wellhead and a pressure handle connected with the well center at the tail. It's about twenty or thirty centimeters long. It's often used and brighter. The well core is a diversion skin, and the groundwater pressure is induced by the action of this diversion skin and the well core.