Heater for large flows at low pressure losses

Claim 1

A heater for a large flow of air to be heated at a low pressure loss for use in an incinerator, the heater comprisng in combination: a cylindrical shell, a cylindrical sleeve mounted coaxially in the shell and separating to form an inner flow space and an outer flow space, a bellows positioned about the sleeve outwardly of the shell and connecting the sleeve expandably to the shell at one end of the shell and the sleeve connected fixedly to the shell at the other end of the shell, air means for passing the air to be heated through the outer flow space, hot gas means for passing a hot gas through the inner flow space, the hot gas means including at least one burner connected to supplies of fuel and oxygen as well as penetrating the shell to introduce the hot gas into the inner flow space, the sleeve having an entrance end for entry of the hot gas and an exit end for exit of the hot gas, outer extended surface projecting from the sleeve into the outer flow space, a baffle mounted inwardly of the sleeve and organized to channel the hot gas into a convection passage boardered outwardly by the sleeve and inwardly by the baffle, inner extended surface projecting from the sleeve into the convection passage, the baffle cylindrical with a closed end projecting into the exit end of the sleeve so that the convection passage is annular and located in the vicinity of the exit end, means to provide superatmospheric pressure in the inner flow space.