Patent ID: 8201713

Claim:
A pressure drop compensation member suitable to be placed in a fluid dispensing channel, the pressure drop compensation member comprising: (a) a sleeve; (b) a piston adapted to be acted upon by a fluid in a first direction, the piston comprising one or more flow slits through which all of said fluid flows through the piston, the piston comprising: 1. a base comprising a first surface adapted to be acted upon by the fluid in the first direction, a second surface, and one or more flow ducts fluidly linking the first surface with the second surface to allow fluid to flow through the base; and 2. a body comprising a body proximal portion attached to the second surface of the base, a body distal portion attached to the proximal portion and an internal wall disposed at the interface of the body proximal portion and the body distal portion, wherein the body distal portion comprises the one or more flow slits, defines a distal portion free end and a distal portion internal volume and is at least partially received within the sleeve and wherein the body proximal portion comprises: i. a peripheral wall including a proximal portion internal surface and a proximal portion external surface, the proximal portion internal surface defining a proximal portion internal volume that is delimited at one end by the base and, at the other, by the body distal portion, wherein the one or more flow ducts of the base communicates directly with the proximal portion internal volume to allow fluid to flow through the base to the proximal portion internal volume, and ii. one or more flow apertures fluidly linking the proximal portion internal surface with the proximal portion external surface to allow fluid to flow from the proximal portion internal volume to the exterior of the proximal portion, wherein the internal wall prevents the fluid from flowing directly from the proximal portion internal volume to the distal portion internal volume; and (c) an elastic member capable of acting on the piston in a second direction opposite to the first direction; wherein the piston is slidably movable within the sleeve to adjust the area of each of the one or more flow slits, subject to a minimum area of each of the one or more flow slits always being available for fluid flow, and wherein, in use, if the pressure exerted by the fluid on the piston drops, the elastic member acts to move the piston in relation to the sleeve to increase the area of each of the one or more flow slits in order to maintain a substantially constant flow of fluid through the fluid dispensing channel.