Multistation reaction injection moulding appts. - in which each station is fed with components via a supply and a return manifold

摘要

In apparatus for reaction injection plastics material at separate stations, each of the components is fed from a source along a supply manifold and back to the source via a return manifold. Each station has a mixer/injector head connected via feed and return shunt lines to the supply and return manifolds. First valves are provided to stop circulation in the manifolds and second valves are provided to prevent circulation of components from the manifolds to the heads. In use, to effect injection with a chosen head the first valves are closed to prevent manifold recirculation and the second valves of all the heads except the chosen one are closed. This causes the components to flow along the supply manifold and down the shunt line of the chosen head for dispensing. The arrangement is of particular use in injecting foamed resin, e.g. polyurethane, into refrigerator cabinets fed from a main conveyor to positions beneath the heads. One or more heads can be used at the same time.