Patent ID: 6202896
Filing Date: 2001-03-20
Classification: B05B

Abstract:
A pump of the type including a moving member mounted to move relative to a support, the moving member having a central duct in which substance to be dispensed penetrates via at least one opening, the support co-operating with the moving member to define, around said central duct, a pump chamber of variable volume, said pump also having a membrane with a central portion in the form of a sleeve that is open at its top end and closed at its bottom end, said central duct being inserted in said central portion, the membrane being organized to isolate the pump chamber from the opening(s) of said central duct while the volume of the pump chamber is increasing and substance is being sucked into it, wherein at least one of the membrane and the central duct is shaped to prevent a leakproof annular zone forming between the membrane and the central duct which would prevent the substance contained in the pump chamber from flowing via said central duct while the volume of the pump chamber is decreasing.