the present invention relates to method and apparatus for preheating pulverous materials , such as glass batch constituents , prior to their introduction into a melting furnace to increase the efficiency and output of the melting installation . the pulverous materials , including a dessicant - type constituent , are passed downwardly through a shell and tube preheater to absorb the contained moisture during their downward travel through the preheater . the inclusion of a dessicant material prevents moisture condensation and build - up of the pulverous material within the tubes , especially in cooler areas , which can cause tube pluggage . the subject invention is of particular utility to the glass industry and especially glass melting furnaces , but is also applicable to other types of furnaces .