Polyurethane foam insulating jackets and pipes - by spraying foam onto moving tube, segmenting and halving

摘要

The jackets are produced by (a) glueing together a no. of overlapping paper or cardboard layers around a horizontal cylinder to form a helical tube, (b) continuously rotating and forwardly moving the tube by a driving belt around the tube, (c) spraying polyurethane foam on the tube by a fixed nozzle, to form a coating (d) cutting the coated tube into lengths by a device movable parallel to the tube and also across the axis of the tube, this device being controlled by a photo-electric cell, and (e) diametrically cutting through the lengths to give two halves. High prodn. rate of prods with isotropic structure and chosen density.