Heat treating furnace

Claim 1

A HEAT TREATING FURNACE COMPRISING AN ELONGATED HOLLOW FURNACE BODY OPEN AT ITS ENDS, MOVABLE CLOSURES FOR THE ENDS OF THE FURNACE BODY, DRIVEN CONVEYOR MEANS IN THE LOWER PART OF THE FURNACE BODY, HEATING MEANS IN THE UPPER PART OF THE FURNACE BODY, MEANS TO SUPPLY A NON-REACTIVE GAS TO THE FURNACE BODY, A SERIES OF SUPPORTS FOR MATERIAL TO BE TREATED FITTING END-TO-END ON THE CONVEYOR MEANS TO BE MOVED THROUGH THE FURNACE BODY THEREBY, TRACKS EXTENDING TRANSVERSELY OF THE FURNACE BODY AT THE ENDS THEREOF, A PAIR OF OPEN ENDED HOUSINGS MOVABLE RESPECTIVELY ALONG SAID TRACKS INTO AND OUT OF ALIGNMENT WITH THE ENDS OF THE FURNACE BODY, MEANS TO SEAL THE OPEN ENDS OF THE HOUSINGS AGAINST THE OPEN ENDS OF THE FURNACE BODY, CONVEYOR MEANS IN THE HOUSING ALIGNED WITH THE CONVEYOR MEANS IN THE FURNACE BODY TO CARRY A SUPPORT, AND MEANS TO CIRCULATE A PURGING GAS THROUGH THE HOUSINGS WHEN THEY ARE SEALED AGAINST THE ENDS OF THE FURNACE BODY, THE CLOSURES BEING OPENABLE TO PERMIT MOVEMENT OF SUPPORTS BETWEEN THE HOUSINGS AND THE FURNACE BODY WITHOUT OPENING THE FURNACE BODY TO ATMOSPHERE.