Single dose air pressure operated dispenser

Claim 1

An air pressure-operated dispenser for spraying a single dose of a fluent material or liquid or powder form, and comprising: a. a single dose container having a compressed air inlet opening and a closable discharge orifice, the interior space and the inlet opening and the discharge orifice thereof being free from obstructions to the flow of compressed air thereinto and to flow of a mixture of a dose of fluent material present in the interior space from the discharge orifice thereof; b. means for closing the discharge orifice in a non-dispensing position of the dispenser; c. an air-compressing piston pump having a compressed air outlet from a compression space thereof; and d. value means for releasing a flow of compressed air after build-up of a determined excess pressure, the inlet opening of the single dose container being joined to the compressed air outlet of the compression space and wherein the valve means comprise an obturator located at the junction of the inlet opening and the compressed air outlet, the obturator being a breakable diaphragm across the junction, and pin means mounted on the frontal face of the piston of the pump adapted to rupture the diaphragm when the piston reaches a position near the end of its compression stroke.