Generally, fluoroplastic plates cannot be used if their swelling exceeds a certain amount

Fluorine rubber sheets generally cannot be used if the swelling degree exceeds 30%. In the case of low pressure (especially below 0.5MPa) and vacuum, it is more suitable to use rubber pads. The rubber material has good density and low air permeability. For example, fluorine rubber is suitable as a sealing gasket for vacuum pump vessels, and the vacuum value can reach 1.3×10-7Pa. When the rubber mat is used in the vacuum range of 10-1~10-7Pa, it must be processed by baking and vacuuming. The price of asbestos rubber sheet is lower than that of other gaskets, and it is convenient to use; the biggest problem is that although rubber and some fillers are added to the gasket material, it is still unable to completely fill the intertwined fine pores, and there is a small amount of infiltration.