| 摘要 |
PURPOSE: A mixing head assembly is provided to completely isolate polyurethane foam from release lubricating oil when a piston is backed up and to smoothly release and lubricate a cleaning piston rod by flowing the release lubricating oil to the wall of a path along a threaded groove. CONSTITUTION: A mixing head assembly is for producing polyurethane foam through a discharge pipe(1) after uniformly mixing polyol with isocyanate in a mixing chamber(8). The mixture of polyol and isocyanate are solidified promptly due to the characteristics of the materials. When being discharged through the discharge pipe, the mixture is stuck on the wall of the path in the discharge pipe and a body(2). At least one of radial grooves are formed on the front end of a cleaning piston rod(5). A cleaning packing(5-6) is installed in the groove. A threaded groove(5-7) is installed on the circumference of the rear end of the radial groove. Mixing of polyurethane foam and release lubricating oil is completely restrained while a piston is backed up. With forward movement of the piston rod, the release lubricating oil flows into the wall of the path of the discharge pipe along the threaded groove. Therefore, release and lubrication of a cleaning piston rod are performed smoothly.
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