GB2406330A — A dispensing apparatus having a metering chamber

USPTO Abstract

A hand-held multi-dose dispensing apparatus (10) comprising a metering chamber (20) having an axis (21), an end portion (22) at one axial end of the chamber (20) and a side body portion (23) extending from the axial end portion (22), a piston arrangement (30) movable with a piston stroke along the axis of the metering chamber (20) with a seal portion (34) of the piston arrangement (30) being slidably engageable with an inside surface of a side portion (23) of the metering chamber, an inlet (27) for fluid to enter the metering chamber (20), and an outlet (31,32) for fluid to be dispensed from the metering chamber (20), wherein the inlet (27) is provided on the side body portion (23) of the metering chamber and, in use, during a first portion of the piston stroke, the inlet(27) is in fluid communication with the metering chamber (20) and during a second portion of the piston stroke, the seal portion (34) of the piston arrangement (30) blocks the inlet (27) preventing fluid from passing from the inlet (27) into the metering chamber (20). This dispensing apparatus (10) reduces variations in the shot weight dispensed, by the metering of the fluid commencing at the point at which the piston enters the second portion of its stroke blocking off the inlet.