Seal assembly and valve with same

The component has a flexible membrane (26) comprising an inner membrane edge (261) and an outer membrane edge (262). The flexible membrane with the inner membrane edge is sealed against a force transmission element (50), and with the outer membrane edge is sealed against a body (51). A medium (24) with definite flow limit is enclosed between the membrane and an area of the body, where the area is covered by the membrane. The membrane is made of stainless steel sheet metal and elastomer. A ring i.e. sliding ring (48), is fixed on the force transmission element. The medium with the definite flow limit is utilized as an elastomer and grease. The component utilizes a medium with increased flow limit such as a Bingham fluid, silicone oil and transformer oil.