Method for applying a liquefiable material onto a substrate conveyed in form of a web

Method for applying a liquefiable material in the form of a foam or a high-viscosity solution from a storage container onto a substrate which is conveyed in form of a web, with the aid of a tubular application device which is provided with at least one discharge opening which is oriented in a line transversely to the direction the web is moving, which comprises introducing a stream of the liquefiable material at one end of the application device, metering said stream entering at one end and measuring the quantity of the liquefiable material introduced into the application device per time unit, applying a part of the liquefiable material in the application device through said at least one discharge opening therein onto the web disposed outside the application device, and discharging another part of said stream of liquefiable material at the other end of the application device, flowing liquefiable material continuously through the length of the tubular application device from the one end to the other end, and conducting said discharged part of the stream back to the storage container, passing said discharged part of the stream through a flow meter and measuring the flow-through quantity per time unit of said discharged part of the stream, comparing the difference of the measured quantities of liquefiable material entering the application device at the one end and liquefiable material discharging at the other end of the application device per time unit to a nominal value, and regulating the flow of the stream by dosing such that the difference of the measured quantities of liquefiable material entering at one end of the application device and discharging at the other end of the application device per time unit approaches the nominal value.