Top-hat and lift-bottom furnaces are chamber furnaces in which either the furnace (with fixed bottom) can be moved upwards or the bottom (with fixed furnace) can be moved downwards.
In contrast to a conventional chamber furnace, the heat field is more even and the working area is accessible from almost all sides. The working chamber can be designed both round and square. Optionally, the working chamber can be equipped with gas flushing or circulating air.
Depending on the heating system used, top-hat and lift-bottom furnaces can be used for temperatures up to 1750 °C.