APPARATUS FOR THE MANUFACTURE OF A HOMOGENEOUS OR CELLULAR PLASTICS MATERIAL THAT FORMS A REACTION MIXTURE FROM TWO LIQUID REACTIVE COMPONENTS

摘要

The present invention is directed to an apparatus for producing a reaction mixture from at least two fluid components comprising: (A) a storage container for each component; (B) feed pipes leading from each storage container via metering pumps to injection nozzles; (C) return pipes leading from each injection nozzle to the storage containers; (D) the injection nozzles opening into the mixing chamber of a mixhead, the mixhead having an outlet opening downstream of the injection nozzles, each injection nozzle comprising (i) a housing, (ii) a bore arranged in the housing, the bore connected to a feed pipe and a return pipe, (iii) a nozzle needle within the bore, the nozzle needle being provided with (a) an annular groove for connecting the feed pipe and the return pipe, (b) a sealing surface, and (c) a needle spindle, (iv) a sealing surface in the housing, the sealing surface adapted to contact the sealing surface of the nozzle needle, and (v) a central nozzle bore located in the sealing surface (vi) wherein the needle spindle is adapted to pass into and/or through the central nozzle bore; characterized in the (E) the nozzle needle and the needle spindle are separate parts, wherein the needle spindle consists of a ductile, highly elastic steel and is replaceably-mounted in the nozzle needle and surrounded by a recess formed in the nozzle needle.