Abstract: A valve for a pressure pack primarily designed for dispensing powders in the absence of liquid. The valve has the usual housing, gasket, stem, spring and mounting flange components but the special problems of dispensing powders are overcome (a) by introducing a liquid film between the sealing surfaces; (b) by physically removing particulate material from the valve stem by wiping and (c) by providing a double seal between the pressurized contents of the can and the atmosphere. In a further modification, the valve stem is connected to or continuous with the dip tube.

Abstract: A pressurized dispensing device contains a fluid product, either a dry powder or a liquid, to be dispensed and a reservoir containing a propellant sorbed by a sorbent material, the reservoir having a vapor-permeable wall to permit propellant gas to pass through and pressurize the headspace of the device.