Carl C. Herb

Sound insulated bellows‐type air terminal valve

A bellows assembly is secured to a retainer by extrusions having a mushroom or arrow shaped cross section. Air flowing through the terminal impinges upon an impervious film covering the central portion of the device and is diverted into two flow paths. Initially the flow paths extend between the film and the cutoff plates which coact to form a tight shut off. Downstream of the cutoff plates, the flow paths are between a porous foam covering the bellows and foam surrounding the cutoff plates to provide a sound reducing effect. If necessary or desirable, the back of the retainer may be covered with foam or other suitable sound insulating material.