Patent ID: 8443840

Claim:
An excessive pressure release valve which comprises: an elastic rubber plate having an upper surface and a lower surface; and a reversibly openable and closable slit passing through the upper and lower surfaces of the elastic rubber plate for releasing an internal excessive pressure to the external world when the slit is pushed and opened toward the upper surface side by the internal excessive pressure stressing on the lower surface side of the elastic rubber plate, wherein the elastic rubber plate is made of a silicone rubber containing 1 to 20% by mass silicone oil, the elastic rubber plate has a thickness ranging from 0.3 mm to 20 mm, a diameter ranging from 2 mm to 40 mm, a Durometer A hardness ranging from A20 to A80 according to Japanese Industrial Standard K6253, and the slit having a length that is 5 to 80% of the diameter, and the slit also having wall surfaces, wherein the silicone oil saturates the wall surfaces of the slit and facilitates opening and closing of the slit, and wherein the silicone rubber is methyl vinyl silicone rubber and the silicone oil is methyl phenyl silicone oil, or the silicone rubber is methyl phenyl vinyl silicone rubber and the silicone oil is dimethyl silicone oil.