An appliance for discharging a non-compressible liquid, creamy or pasty medium comprising
- (a) an external elongated, rigid-walled container, having an open top end and an open base end, and a central axis extending longitudinally therethrough,
- (b) a contracting element having a top end and a bottom end, of caoutchouc-type macromolecular material, said element being located in the interior of said external container,
- (c) a flexible, expandable product container mounted in the interior of said contracting element and having an upper end and a lower end;
- said contracting element being adapted for exerting squeezing pressure on said product container,
- (d) an elongated, hollow core body which is inflatable radially with regard to said longitudinal container axis, lodged in the interior of said flexible product container about said longitudinal axis of said external container, having a top end and a bottom end,
- (e) first valve means mounted in said open top end of said external container and closing the same off, said top ends of said contracting element, said upper end of said product container, and said top end of said core body being sealingly attached to said first valve means,
- said first valve means comprising a valve-controlled passageway therethrough for flow of said non-compressible medium between the interior space in said product container surrounding said core body, and the outside,
- whereby said non-compressible medium can be filled into, and discharged from, said product container,
- (f) second valve means on the inside of said open base end, said bottom end of said core body, said lower end of said product container and said bottom end of said contracting element being sealingly attached to said second valve means, whereby, while said contracting element, said product container and said core body are fully elongated downwardly along said longitudinal axis, said valve means will come to rest against said base end and close off the interior of said external rigid-walled container outside said contracting element,
- said second valve means comprising a valve controlled passageway therethrough for air into said core body from the outside, thereby inflating said core body to a determined maximum expansion, said core body, when in inflated condition being compressible, with pressure increase in the interior of said core body, by non-compressible medium filled into said product container, and being squeezed by said contracting element,
- (g) said external container having a sidewall strong enough to limit the radial expansion of said product container and said contracting element enveloping said product container to the internal width of said external container, and
- (h) said contracting element being prestressed when having its ends mounted in said first and second valve means and when said core body is inflated to have substantially cylindrical configuration intermediate said top end and said bottom end thereof,
- whereby inflation of said core body compensates for loss of contractional force of said contracting element.