Readily assembled unitary safety valve used in e.g. an engine oil filter cartridge

摘要

A safety valve (40) closes and opens a fluid passage (35), in a wall of a cylindrical fastening section (33), as a function of pressure difference between the inside and outside of the fastening (33). The fastening is open at the front, to receive the safety valve (40). The safety valve comprises an annular, resilient seal contacting the fastening when the fluid passage (35) is closed. It separates from the fastening, to open the fluid passage. An annular leading section is joined in one piece with the seal. This is relieved at the front, ahead of the sealing section, forming a gap into which the fastening section enters and fits readily, as the seal deforms resiliently.