Collapsible tube valve

Claim 1

A pressure operated valve for controlling the flow of dry particulate materials comprising: an elongated, circular cross section, uniform outer diameter tube formed of a flexible rubberlike material; said tube being formed into three integral portions, namely, an elongated, intermediate valving portion and elongated opposite end portions, with the end portion walls being at least twice as thick as the intermediate portion wall thickness, so that the internal diameter of the intermediate portion is considerably greater than the internal diameter of the end portions, and the junctions between the inner wall surfaces of the intermediate and the respective end portions being formed as a gradual taper defining truncated conical shapes; three radially inwardly extending V-shaped cross section ribs formed integral with the inner wall surface of the intermediate portion and extending the full length thereof parallel to the axis of the tube, with the ribs being equally spaced apart and their apices each being located along a radial plane of the tube; and the wall of the intermediate portion progressively collapsing inwardly both longitudinally and radially starting at the longitudinal center of the intermediate portion and centrally between the ribs, upon application of uniform pressure to the exterior of the intermediate portion, to form three rounded, inwardly extending wall segments, with no sharp bend lines, until all three segments form roughly line contacts with each other along lines close to and parallel to the tube axis for shutting off the flow of dry particulate material passing through the tube, and wherein the progressive longitudinal collapsing squeezes such material longitudinally away from the longitudinal center of the intermediate portion for minimizing trapping such material between the segments.