VALVE FOR RESPIRATOR

摘要

A valve for a respirator has an elastomeric valve member (18) of generally dished form with an annular channel (25) around its central portion (24). The member (18) is secured at its center by a shouldered conical stem (19) and seals round its periphery (23). The channel (25) allows a sudden collapse of resistance to opening force in the direction of the arrow A above a predetermined amount, but a positive biassing action towards closure. The edges of the channel (26,27) are slightly axially displaced from one another. Both inlet and outlet valves of a respirator may be equipped with such a valve member.