Prodn. of extruded foam section - feeds foaming mixt. into plastic film which is folded over and welded into tube, allows mixt. to expand, and passes tube to forming tools

摘要

Extruded sections are produced from fire-protective foam by using a liq reactive mix. A flexible tube is filled with the mix which is allowed to foam up in the absence of air whilst a set quantity of the material plus the tube is drawn into a foaming chamber; the material is then formed into the section in the tube whilst still plastic. The process can utilise rollers which are pref made of foam, rubber or other elastic material. A tube (3) feed foaming mix into a strip of film (1) which is folded over to form a tube with overlapping edges; the tube (3) extends through the stage (7) where the edges are welded together and through the cbmpressing point of two rollers (8). These rollers (8) can have semi-circular grooves. A cord, wire, cable or similar can also be fed into the centre of the foaming space. The inner tube (3) ends in the expansion reaction space (15), where two rollers (16) restrain the volumetric expansion to the desired extent by adjusting the gap between the rollers. While the foaming reaction proceeds, the material passes through a forming tool (21) of two parts (22, 23) and of suitable length for the speed of the moving prod. These parts (22, 23) can be heated or cooled as required. Finally the prod is drawn off by traction rollers (27, 28). ADVANTAGE - The process produces the sections free of any large occlusions and with low wt. The prods are universally applicable for a variety of purposes in the fire protection field.