Patent ID: 8678243
Filing Date: 2014-03-25
Classification: B05B

Abstract:
1. A fluid dispenser for use with a fluid supply, the dispenser having a dosing chamber, a fluid outlet, and a piston member which is arranged to sealingly stroke in the dosing chamber (i) in a first direction for filling the dosing chamber with fluid from the supply, and (ii) in a second direction to dispense fluid from the dosing chamber towards the fluid outlet, wherein: the dosing chamber has first and second sections of different widths, the first section is narrower than the second section and located in the second direction relative to the second section, the piston member is in constant sealing contact with the second section as it strokes in the first and second directions, but only in sealing contact with the first section in a portion of the strokes in the first and second directions, the first and second sections are in fluid communication when the piston member is not in sealing contact with the first section, the sealing contact of the piston member with the first section as the piston member strokes in the second direction is such that the first section is sealed-off from the second section and that the piston member is able to pump fluid present in the sealed-off first section towards the fluid outlet, the piston member has a fluid conduit for communicating with the fluid supply and through which, in use, fluid is conveyed from the fluid supply into the dosing chamber when the piston member strokes in the first direction, and the fluid conduit has an outlet comprising at least one opening positioned on the piston member to register with the second section of the dosing chamber so that fluid is conveyed from the fluid supply into the second section.