VORRICHTUNG ZUR ABGABE EINES FLUIDES SOWIE AUSGABEKANÜLE HIERFÜR

摘要

A metering cylinder (11) has a piston (18) to pump fluid from a container to an output channel (2) in a delivery cannula. (11) is connected to a valve block (7) which connects with a suction valve system (22) for drawing fluid into the cylinder and an outflow valve (30) for conveying fluid out of the cylinder into (2). (7) is injection molded in one piece with (11) in a plastic with high chemical resistance. The output valve (30) has a plastic valve seat (33) between the valve block (7) and the ball (32) of the output valve. The valve seat acts in conjunction with valve balls (23,32) of the suction (22) and/or outflow valves. Suction valve ball travel is limited by a sleeve (27) in the valve block (7). A delivery nozzle mounted on the free end of the cannula body (1) has an outlet nozzle with an outlet angled relative to the output channel (2). Swiveling of the nozzle around the cannula axis allows fluid to flow back to the container via a return channel (3) running adjacent to the latter in the cannula. The valve block may have a skeletal construction comprising spaced ribs. Cannula mounting on the valve block is in the region of the outflow valve (30). Connection between the valve block and a fluid container is via a nut (34). Cannula and valve block are joined by press fitting the former into a recess in the latter. The metering cylinder and valve block may be an integral unit or the cylinder can be screwed into the valve block. The cylinder may form an insert which is located, in an external jacket (16) and is preferably injection molded into the latter. Cannula, valve block and metering cylinder may also be injection molded as a single item. Independent claims are included for: (a) a cannula for a fluid dispenser with an output channel and a return channel which can be connected near the outlet end to allow fluid to be transferred from one to the other; (b) an injection molding tool comprising two or more parts forming a cavity for molding a valve block and metering cylinder as a one piece unit in a thermoplastic plastic; and (c) a process for manufacturing a fluid dispenser with a one piece valve block and metering cylinder in a chemically resistant plastic.