Air breather assembly

Claim 1

An air breather assembly, for mounting on a container wall having an opening, comprising an apertured mounting for securing over said opening, a cap, means on said mounting and on said cap whereby said cap is engageable onto and disengageable from said mounting by relative rotation, means positioned between said mounting and said cap for forming a fluid-tight seal therebetween when said cap is engaged on said mounting, means in said cap defining an air flow path between its exterior and the aperture of the mounting, first valve means disposed in said cap and positioned across said path and adapted to close said path against outward flow of air, means resiliently loading said first valve means and normally holding said valve means in closing position unless certain pressure is exceeded, said first valve means including a movable valve member in the form of an apertured housing urged by said loading means against a valve seating, and second valve means disposed in said cap and positioned across said path and adapted to close said path against inward flow of air from atmosphere, said second valve means including a movable valve member in the form of a resiliently deformable flange positioned within said housing and arranged in its unstressed condition to overlie and thereby close the aperturing of said housing unless and until a sufficient pressure is applied inwardly from atmosphere to deform it away from said housing and thereby open said aperturing.