Typically, the higher-temperature continuous furnaces used for sintering operations are known as “pusher furnaces” or “walking-beam furnaces.” A pusher furnace moves the work through on a series of boats or plates. One boat
is pushed against another in a continuous train. A pusher furnace only pauses long enough to remove a boat
at the exit end and add one at the entrance end. This is considered a constant push.
A walking-beam furnace utilizes a pusher mechanism to bring the boat
into the furnace and place it on the beams
. These beams
are analogous to a series of rails
. The rails
are on cams, which lift up, forward and down, essentially walking the boat
or carrier through the furnace. At the exit end, the boats are then commonly transferred onto a belt for the cooling section.
A tube furnace
is an electric heating device used to conduct syntheses and purifications of inorganic compounds and occasionally in organic synthesis. One possible design consists of a cylindrical cavity surrounded by heating coils that are embedded in a thermally insulating matrix. Temperature can be controlled via feedback from a thermocouple. More elaborate tube furnaces have two (or more) heating zones useful for transport experiments. Some digital temperature controllers provide an RS232 interface, and permit the operator to program segments for uses like ramping, soaking, sintering, and more. Advanced materials in the heating elements, such as molybdenum disilicide offered in certain models can now produce working temperatures up to 1800 °C. This facilitates more sophisticated applications. Common material for the reaction tubes include alumina, Pyrex, and fused quartz.
The tube furnace was invented in the first decade of the 20th century and was originally used to manufacture ceramic filaments for Nernst lamps and glowers.