Radiant tube heater and heat treatment furnace

Abstract

The present invention relates to a radiant tube heater including: a tube provided with openings at both ends; a first cover body and a second cover body configured to close the openings at both ends; at least one electric resistance heating element provided in the tube; a support member provided in the tube and configured to support the electric resistance heating element; a gas inlet configured to allow furnace cooling gas to be introduced into the tube; and a gas outlet configured to discharge the furnace cooling gas introduced into the tube.

What is claimed is: 
     
         1 . A radiant tube heater comprising:
 a tube provided with openings at both ends;   a first cover body and a second cover body configured to close the openings at both ends;   at least one electric resistance heating element provided in the tube;   a support member provided in the tube and configured to support the electric resistance heating element;   a gas inlet configured to allow furnace cooling gas to be introduced into the tube; and   a gas outlet configured to discharge the furnace cooling gas introduced into the tube.   
     
     
         2 . The radiant tube heater according to  claim 1 , wherein
 the tube includes a curved portion, and the openings at both ends are open in the same direction.   
     
     
         3 . The radiant tube heater according to  claim 1 , wherein
 the gas inlet is provided in the first cover body that closes one opening of the tube, and the gas outlet is provided in the second cover body that closes the other opening of the tube.   
     
     
         4 . The radiant tube heater according to  claim 1 , wherein
 the support member includes a protruding portion that faces an inner wall surface of the tube while being disposed in the tube, and   the protruding portion includes, on an outer circumferential portion thereof, a plurality of convex portions spaced apart in a circumferential direction and a concave portion that constitutes a part of a flow passage of the furnace cooling gas flowing through the tube.   
     
     
         5 . The radiant tube heater according to  claim 1 , comprising:
 a first electric resistance heating element provided at a first end side portion of the tube; and   a second electric resistance heating element provided at a second end side portion of the tube.   
     
     
         6 . A heat treatment furnace configured to perform a heat treatment on an object to be treated, wherein
 the radiant tube heater according to  claim 1  is provided as a heating unit for heating the object to be treated in the furnace.