Polyurethane reagents mixing head - in which mix flows through valve with tapered section but allowing passage of purging piston

摘要

A mixing head for at least two liquid materials, and partic. for polyurethane mouldings prodn., has a mixing chamber with >=2 inlets for the materials and with an axially sliding purging piston, and a valve before the outlet in the chamber. This valve rotates and has a central hole whose section increases towards the outlet of the chamber but has a cross-section area on the piston side which equals that of the piston. The simple effective design permits reliable sealing on the outer side of the valve.