Abstract
The relations between the compression ratio and the leak of some rubber gaskets having practical dimensions were investigated by a helium leak detector. As the materials of the samples were used acrylonitrile-butadiene, chloroprene, natural and silicone rubber. Testing was tried for three different kinds of cross section, circular, square and semicircular, and also for the gaskets of seven different shore hardness from 30 to 90. Five joint less pieces for each kind of sample, 420 pieces in total are made as samples to be tested.
There are two kinds, of the leak in a gasket, namely usual “leak” and permeation. The former is a leak through the space between the surface of gasket and that of a gasket seat, and the latter is a leak through the gasket material itself. These two kinds of leak can be distinguished clearly by experiment. The former leak can be made less the 1×10-9mmHg·l/sec when rubber of any kinds is compressed by 1015%. The latter leak can be diminished only when the surface area of the gasket exposed to both vacuum and atmosphere is made small.
