GB644195A - Improvements in or relating to closuring devices for sealing containers - Google Patents

Abstract

644,195. Vacuum closures. HOFMANN, R. June 30, 1948, No. 17571. [Class 125 (iii)] A sealing device for a container comprises a closure member from which depends an elastically deformable diaphragm, means being provided between the closure and diaphragm to deform the latter to effect displacement of sufficient air from the container to create, on release of the said means and return of the diaphragm towards its original shape, a vacuum in the container, whereupon external air pressure causes the peripheral portion of the diaphragm to conform hermetically to the rim of the opening and the closure is concurrently pressed downwardly thereon. In the form shown, a circular rubber diaphragm 14 is secured by its edge to the rim of a closure member 12. The closure member has a central hole through which passes a push-rod 18 formed at its lower end into a head 17 which engages the centre of the diaphragm. To seal the container, the closure is held and the rod 18 pushed down to the position shown in Fig. 2, thus stretching the diaphragm. The closure is then placed on the container and the rod released, the diaphragm tending to return to its original shape, as shown in Fig. 3, so causing a partial vacuum in the container. External air pressure causes the diaphragm periphery to seal onto the container rim 11 and its internal surface 23, the closure member being drawn down to clamp the diaphragm in position. A vacuum release valve 24, operated by a push button 30, may be accommodated in the head 17, to allow easy removal of the closure. Alternatively the valve may be omitted, the vacuum then being destroyed by pushing the rod 18 down until the pressure in the container equals atmospheric pressure, when the closure can be lifted off.