Vacuum Vertical Pit-Type Annealing Furnaceis controlled by three parts of the furnace:upper,medium and lower.The actual process temp of the hearth. Rubber seals the outlet of the hearth and the water-box unit is supplied.There is a jacket of air between circulating water and the wall of the hearth to reduce the hot loss.Besides the following specifications,the factory manufactures other size hearth and furnace body