Liquid metering device with time delayed closure

In apparatus for dispensing measured quantities of liquid comprising a measuring chamber with an inlet at one end which, in use, is connected to the mouth of an inverted bottle, and an outlet opening at the other end through which the measured quantity of liquid is dispensed, the measuring chamber incorporating a double-headed plunger which in a first position closes the outlet while leaving the inlet open so that the measuring chamber fills with liquid from the bottle, while in a second position the plunger closes the inlet and leaves the outlet open so that the measured quantity of liquid drains from the measuring chamber, and delay means for holding said plunger in said second position for a predetermined period of time sufficient to ensure delivery of the entire contents of the measuring chamber, the improvement comprising a linkage system, which has an operating member disposed adjacent to the outlet of the measuring chamber, said linkage system being coupled to said plunger and to said delay means, and a first spring means to return said plunger to its first position automatically at the expiration of the delay period afforded by the delay means, wherein the delay means comprises a piston and cylinder type assembly in which the piston is driven in the cylinder by a second spring means at a rate determined by the rate at which a fluid flows through a restricting orifice provided in said assembly.