| 摘要 |
Mixer for liq. pref. polyurethane-forming, reactants, comprises a mixing chamber with inlets for each reactant and an outlet for the resulting mixt.; a control piston inside the chamber which reciprocates from a position in which the inlets are clear to a position near the outlets thereby blocking the inlets. The piston has return (recycling) grooves through which the inlets are connected with recycling lines, synchronised with their being cut off from the mixing chamber. The mantle surface of the piston between the recycling grooves is roughened with a grid or diamond pattern. Longer-lasting, more accurate, reliable seal between chamber wall and piston is achieved. |
