| 摘要 |
An indirect heater assembly ( 10 ) comprises a radiant tube heater ( 12 ) and a fan ( 14 ) for generating an air flow over the heater ( 12 ). In an preferred embodiment and in another aspect, the radiant tube heater ( 12 ) comprises a radiant tube burner, an elongate tube 16 and a spiral tube ( 23 ) connected to the elongate tube ( 16 ) by a U-shaped tube ( 25 ). The spiral tube ( 23 ) extends around the elongate tube ( 16 ) coaxially thereof.
|
