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US 5,832,848 AGranted
Fluidized bed heat treatment furnace
AssigneeQuality Heat Treatment Pty, Ltd.
InventorsRay William Reynoldson, Andrew Simpson Fitchett
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AssigneeQuality Heat Treatment Pty, Ltd.
InventorsRay William Reynoldson, Andrew Simpson Fitchett
Estimating the term…
A fluidized bed heat treatment apparatus is provided to be heated by combusting fuel gas in a manner to minimize or prevent the exhaust of carbon monoxide, the apparatus including a retort containing refractory particles to be fluidized, a first inlet in a lower region of the retort for introducing fuel/air mixture into the retort, a second inlet in a lower region of the retort for introducing secondary air into the retort, a temperature sensor located above the first and second inlets, a flame initiator located above the refractory particles, an externally located mixer to mix fuel and air in desired proportions and to supply same to the first inlet, and a control device arranged to control said externally located mixer in response to temperatures sensed by said temperature sensor whereby when the temperature sensor is below a predetermined temperature indicative of the bed being substantially not fluidized, a stoichiometric fuel/air mixture is supplied to the first inlet and when the temperature sensor senses a temperature above the predetermined level indicative of the bed being substantially fluidized, a less than stoichiometric fuel/air mixture is supplied to the first inlet with secondary air being supplied through said second inlet.
A fluidized bed heat treatment apparatus comprising at least one retort containing refractory particles to be fluidized, first inlet means for introducing a fuel air mixture to a lower region of said retort, second inlet means for introducing secondary air into said retort, temperature sensing means arranged to sense temperature in said retort at a level above said first and second inlet means, fuel/air mixing means connected to said first inlet means whereby in a first mode of operation, a fuel/air mixture of at least stoichiometric proportions is supplied to said first inlet means when temperature sensed by said temperature sensing means is below a predetermined temperature and in a second mode of operation, when the temperature sensed by said temperature sensing means is above said predetermined level, said fuel/air mixture is adjusted to be less than stoichiometric proportions with secondary air being supplied via said second inlet means.
A method of operating a fluidized bed heat treatment apparatus having a first retort containing refractory particles to be fluidized, said first retort having first inlet means for introducing a fuel/air mixture to a lower region of said first retort, second inlet means for introducing secondary air into said first retort, temperature sensing means arranged to sense temperature in said retort at a level above said first and second inlet means, and fuel/air mixing means connected to said first inlet means, said method comprising the steps of, when the temperature sensed by said temperature sensing means is below a predetermined level, supplying at least a stoichiometric fuel/air mixture from said mixing means to said first inlet means and when said temperature sensed by said temperature sensing exceeds said predetermined level, a less than stoichiometric fuel/air mixture is supplied from said mixing means to said first inlet means with secondary air being supplied to said retort through said second inlet means.
Dependencies are inferred from the claim text.