Dispenser for dispensing a liquid, in particular a drug, such as for instance eye drops, which dispenser comprises two half portions which can be assembled by means of a snap lock to form a closed chamber adapted to surround a plastic bag containing the liquid, said bag having a constricted portion into which the reservoir of the bag extends, the constricted portion forming a neck with a dosage duct, through which the liquid, after breaking of the constricted portion, may be squeezed by compression of the plastic bag, one wall of the chamber of the dispenser being resilient to such an extent that the plastic bag can be compressed, and the dispenser comprising a shut off for sealing the dosage opening when no liquid is to be supplied. With the object of making the closing means open simultaneously with the compression of the dispenser for squeezing out liquid from the dispenser, the means for sealing the dosage opening are a pair of pincers formed by the two half portions, said pair of pincers being adapted to compress the constricted portion of the plastic bag close to the discharge opening of the dosage duct, at least on one of the half portions of the dispenser the pincers being extended into a ridgid tongue-shaped area of the resilient portion of the wall of the chamber and being supported for performing a seesaww motion together with the pincers when pressure is applied on the tongue-shaped area.

A self-sealing valve is provided for fluid dispensing packages and the like, of the type which are compressed and decompressed to dispense therefrom liquids, pastes, powders and other similar flowable materials. The valve has a marginal groove extending along one face thereof in a closed pattern to define a central area inside the groove, and an outer area outside the groove. Ribs extend between the center and outer areas of the valve to bridge the groove, and selectively support the center valve area in a trampoline-like fashion. A slit extends through the center valve area, and into at least a portion of the groove to form an orifice that shifts between outwardly open, closed, and inwardly open positions in response to compressing and decompressing the container.

A dispensing valve assembly for dispensing a fluid product and preventing air from being drawn into the fluid product through the valve includes a flexible diaphragm valve (10, 50, 100) and a valve seat insert (12, 58, 102). The flexible diaphragm valve flexes from a concave closed position to a convex open position in which fluid product is dispensed through a dispensing opening (26, 56, 116) in the diaphragm. The valve seat insert is positioned adjacent an inside surface of the diaphragm valve in its closed position to prevent the valve from buckling inward and prevent air from passing into the fluid product through the valve.