METHOD AND APPARATUS FOR CONTROLLING THE DENSITY OF A FOAM

摘要

This invention relates to a method and apparatus for controlling the density of a foam on a carpet structure. The method involves measuring the electrical conductivity of a foam and adjusting the density of the foam in response to the measured electrical conductivity to prepare a foam having a desirable density. The apparatus comprises means for generating and applying a foam, said means being connected by an enclosed pathway. Located within the enclosed pathway is an electrical conductivity sensor. The conductivity sensor is electronically connected to a translation means. The conductivity sensor provides an electrical signal, related to conductivity of the foam, to the translation means. The translation means is connected to a gas flow controlling means. Based on the signal received from the conductivity sensor, the translation means provides a signal to gas flow control means which signal influences gas flow control means to increase or decrease the density of the foam thereby changing the density of the foam until a predetermined desirable density is achieved. In the past, the density of the foam has been controlled by visual inspection of the foam as it is applied to the carpet structure. This method of control has been found to be less than desirable. This invention provides an accurate method of controlling the density of the foam within a narrow range, thus enabling the application of the minimum amount of foam necessary to achieve the desired physical properties.