Self-cleaning, mixing apparatus and method for the production of

Abstract

A high-pressure self-cleaning mixing apparatus adapted to mix at least first and second reactive polyurethane-forming components and feed the mixed components to a mold is disclosed. The apparatus includes at least a mixing chamber, first and second feed passages, first and second recycle passages, and a cleaning member having at least first and second longitudinally-extending recycle grooves spaced from each other. The cleaning member is movable between an open position in which the first feed passage radially feeds the first polyurethane-forming component to the mixing chamber and a closed position in which the first longitudinally-extending recycle groove communicates the first feed passage with the first recycle passage to recycle the first polyurethane-forming component instead of feeding the first polyurethane-forming component to the mixing chamber. The second feed passage may be communicated with a longitudinally-extending passage of the cleaning member to permit the second polyurethane-forming component to be fed into the mixing chamber along an axial direction of the mixing chamber. A valve member may be provided to prevent the flow of the second polyurethane-forming component to the mixing chamber by recycling the second polyurethane-forming component to the second recycle passage. Spacing between the first and second grooves seals the first feed and recycle passages from the second feed and recycle passages.