Importance

Loading Importance Indicators...

Abstract

A foam material, used, for example, as a backing material on rugs, is produced by continuously pumping a viscid raw material through a flow meter into a mixer in which the raw material is foamed up by controlled supply of an air flow. For maintaining the density of the foam constant the raw material is passed through a specific weight detector and the foaming air supply is controlled based on the measuring outputs of both the flow meter and the weight detector. According to the invention there is used two specific weight detectors, one at each side of the supply pump, and by processing their combined measuring outputs in a control calculator it is possible to eliminate a control inaccuracy otherwise resulting from the fact that the measurements partly refer to the raw material as under increased pressure compared with the ambient pressure where the foam leaves the mixer.

Loading the Abstract Image...

First Claim