Infrared tube heater

Abstract

An infrared tube heater includes at least one burner device and a beam tube. The burner device includes a burner and a fan. The fan is constructed to supply air to the burner and the burner is constructed to emit a flame into the beam tube. The burner is equipped with a mixer and at least one secondary air duct and the burner is constructed in such a way that a portion of the air supplied by the fan is supplied to the mixer and another portion of the air is supplied to the at least one secondary air duct. The mixer is constructed for mixing the air with a fuel, the fuel/air mixture is burned in the flame, and the secondary air duct is constructed to supply the portion of the air supplied to the secondary air duct to the flame without fuel.

1 . An infrared tube heater, comprising:
 a beam tube;   a burner device including a burner and a fan;   said fan configured to supply air to said burner;   said burner having a mixer and at least one secondary air duct, said burner configured to supply a portion of the air supplied by said fan to said mixer, said burner configured to supply another portion of the air supplied by said fan to said at least one secondary air duct, and said burner configured to emit a flame into said beam tube;   said mixer configured to mix the air with a fuel for burning a fuel/air mixture in the flame; and   said at least one secondary air duct configured to supply said portion of the air supplied to said at least one secondary air duct to the flame without fuel.   
     
     
         2 . The infrared tube heater according to  claim 1 , wherein said at least one secondary air duct is a plurality of secondary air ducts, each of said secondary air ducts has a respective outlet, and said mixer has at least one outlet for the fuel/air mixture. 
     
     
         3 . The infrared tube heater according to  claim 2 , wherein said outlets of said plurality of secondary air ducts are disposed around said outlet of said mixer. 
     
     
         4 . The infrared tube heater according to  claim 2 , wherein said outlet of said mixer is provided with a flame tube, and said outlets of said plurality of secondary air ducts are disposed around said flame tube. 
     
     
         5 . The infrared tube heater according to  claim 2 , wherein said outlets are configured to cause a flow rate of the fuel/air mixture at said at least one outlet of said mixer to be lower than a flow rate of secondary air at least at one of said outlets of said plurality of secondary air ducts. 
     
     
         6 . The infrared tube heater according to  claim 2 , wherein said outlets of said plurality of secondary air ducts together have a smaller cross section than said at least one outlet of said mixer for the fuel/air mixture. 
     
     
         7 . The infrared tube heater according to  claim 2 , wherein each of said outlets of said plurality of secondary air ducts has a smaller cross section than said at least one outlet of said mixer for the fuel/air mixture. 
     
     
         8 . The infrared tube heater according to  claim 2 , which further comprises a flame tube connected to said at least one outlet of said mixer, said flame tube having a cross section being larger than a cross section of each of said outlets of said plurality of secondary air ducts. 
     
     
         9 . The infrared tube heater according to  claim 1 , wherein said mixer is a Venturi mixer. 
     
     
         10 . The infrared tube heater according to  claim 1 , wherein said mixer has an inlet nozzle and a mixing unit with a mixing chamber. 
     
     
         11 . The infrared tube heater according to  claim 10 , wherein said mixing chamber has a cavity with an inlet for air and fuel and an outlet for the fuel/air mixture, and said cavity has a cross section increasing from said inlet to said outlet. 
     
     
         12 . The infrared tube heater according to  claim 11 , wherein said inlet of said mixing chamber has an annular gap formed by said inlet nozzle and configured to introduce fuel therethrough. 
     
     
         13 . The infrared tube heater according to  claim 12 , wherein said inlet nozzle has a tubular element configured to introduce the air into said mixing chamber, said tubular element being surrounded by said annular gap.