Combustion heater

Abstract

A combustion heater ( 1 ) comprises an inner tube ( 20 ) having a supply passage ( 21 ) for a combustion gas (G) therein and an outer tube ( 10 ) disposed around the outer periphery of the inner tube with a combustion space ( 30 ) interposed therebetween. A hole part ( 24 ) for jetting the combustion gas is formed in the wall of the inner tube. A radiation promoting surface ( 20 B) is formed on the outer periphery of the inner tube. By the structure, the excessive heating of the inner tube is suppressed, and the heating efficiency of the combustion heater is increased.

1 . A combustion heater comprising an inner tube having a supply passage for combustion gas in an inner portion, and an outer tube disposed to provide a separated combustion space in an outer periphery of the inner tube, a hole part for ejecting the combustion gas being formed on a tube wall of the inner tube and a radiation promoting surface is disposed on an outer periphery of the inner tube. 
     
     
         2 . The combustion heater according to  claim 1 , wherein the radiation promoting surface is a coated layer provided on the outer peripheral surface of the inner tube. 
     
     
         3 . The combustion heater according to  claim 1  further comprising a radiation promoting surface on the inner peripheral surface of the outer tube. 
     
     
         4 . The combustion heater according to  claim 3 , wherein the radiation promoting surface is a coated layer provided on the inner peripheral surface. 
     
     
         5 . The combustion heater according to  claim 1 , wherein the radiation promoting surface is formed using a ceramic binder. 
     
     
         6 . The combustion heater according to  claim 1 , wherein a heat transfer member is provided to connect the inner tube and the outer tube in the combustion space and to transfer heat between the outer tube and the inner tube. 
     
     
         7 . The combustion heater according to  claim 1 , wherein the inner tube and the outer tube are disposed concentrically. 
     
     
         8 . The combustion heater according to  claim 1 , wherein the inner tube is disposed eccentrically to the outer tube.