Abstract: The present invention relates to a method for preheating of pulverous materials in a tube heat exchanger prior to their introduction into a melting furnace, with particular application to the delivery by gravity of the vitrifiable starting materials through the heat exchanger to eliminate moisture therefrom prior to introduction of the essentially moisture-free materials into a tank furnace for glass making. The preheating serves to raise the entry-level temperature of the glass batch material and improve furnace fuel efficiency. The preheating involves recirculating at least part of the pulverous glass batch material through the open-ended tubes of the tubular heat exchanger to heat the same and remove moisture therefrom prior to initiating delivery of the glass batch material in preheated condition to the glass melting furnace. The present method is specifically directed at maintaining continuous operation of the preheater upon interruption of material flow through the preheater tubes for any reason.