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US 4,499,911 AGranted
Energy efficient curing and drying system
OwnerWilliam H. Johnsoninventor
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OwnerWilliam H. Johnsoninventor
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Significant amounts of heat energy, otherwise wasted in the curing and drying systems previously known, are recovered and recycled in the multi-chamber system of the present invention to thereby significantly increase efficiency and reduce fuel requirements. Tobacco or other moisture containing material is cured and dried in batches in a plurality of individual chambers, with each chamber having suitable controls for individually controlling the temperature and humidity conditions of the curing air which is circulated through the chamber. Means and methods are disclosed for recovering and recycling the heat content of the heated exhaust air from the respective chambers, for using solar energy for further heating the air, and for recovering and recycling the heat energy of the batch of material as it is cooled down at the end of the curing and drying cycle.
A method for more economically drying a moisture-containing material, such as tobacco, by a flow of heated air, said method comprising
A method for more economically curing and drying a moisture containing material, such as tobacco, by a flow of heated air, said method comprising
In a method for curing tobacco in which air, under controlled conditions of temperature and humidity, is directed in a recirculating flow path through a batch of tobacco leaves disposed in a curing chamber, with the air being heated as necessary by a furnace, and with the humidity conditions in the curing chamber being controlled by selectively admitting fresh air to the recirculating flow of air through the curing chamber while discharging exhaust air, the combination therewith of an improvement characterized by substantially reducing the fuel costs for curing the tobacco, said improvement comprising carrying out said curing method concurrently for a series of batches of tobacco in respective individual curing chambers, collecting and combining the flows of heated exhaust air discharged from the respective curing chambers and transferring heat therefrom to a stream of incoming fresh air to thereby preheat the fresh air, and supplying the thus preheated stream of fresh air to at least one of the respective curing chambers.
In a method for curing tobacco in which air, under controlled conditions of temperature and humidity, is directed in a recirculating flow path through a batch of tobacco leaves disposed in a curing chamber, with the air being heated as necessary by a furnace, and with the humidity conditions in the curing chamber being controlled by selectively admitting fresh air to the recirculating flow of air through the curing chamber while discharging exhaust air, said curing method following an established curing schedule in which the tobacco first undergoes a yellowing phase wherein the air is maintained at a temperature of about 95.degree.-105.degree. F. with high air recirculation and relative humidity to promote yellowing of the tobacco leaves, the tobacco thereafter undergoing a drying phase in which the relative humidity is reduced by admitting fresh air and discharging humid exhaust air and while gradually increasing the temperature of the air to about 165.degree. F. to promote drying of the tobacco, the combination therewith of an improvement characterized by substantially reducing the fuel costs for curing the tobacco, said improvement comprising carrying out said curing method concurrently for a series of batches of tobacco in respective individual curing chambers, each being provided with its own furnace, while beginning the curing schedule for each respective batch in the series at a different time so that the batches of tobacco are at different phases of cure and at different conditions of temperature and humidity at any given time, with at least one batch being in the yellowing phase while at least one other batch is in the drying phase, collecting and combining the flows of heated exhaust air discharged from the respective curing chambers and directing the combined flows through a heat exchanger while also directing a stream of incoming fresh air through the heat exchanger for being preheated by the heat of the exhaust air, and supplying the thus preheated stream of fresh air to at least one of the respective curing chambers to thereby reduce the fuel requirements of the individual furnaces.
In a method for curing tobacco in which heated air is circulated through a batch of tobacco leaves to cure and dry the leaves, and wherein the cured and dried leaves are thereafter cooled and a portion of the original moisture content is restored to the tobacco leaves, the improvement which comprises recovering the heat of adsorption which is evolved as the moisture is restored to the tobacco leaves in said batch and transferring this recovered heat to another batch of tobacco leaves which is then undergoing curing and drying.
In a method for curing tobacco in which heated air is circulated through a batch of tobacco leaves to cure and dry the leaves, and wherein cooler air is thereafter circulated through the batch of tobacco leaves to cool the tobacco leaves, the improvement which comprises recovering heat energy from the air which is circulated through the batch of leaves for cooling and transferring a substantial portion of this recovered heat energy to another batch of leaves which is then undergoing curing and drying.
An apparatus for drying a moisture-containing material, such as tobacco, with a flow of heated air which is circulated into contact with the material, said apparatus being constructed so as to permit recovery and reuse of otherwise wasted heat utilized in the drying of the material, and said apparatus comprising
An apparatus for drying a material, such as tobacco, with a flow of heated air which is circulated into contact with the material, said apparatus being constructed so as to permit recovery and reuse of otherwise wasted heat utilized in the drying of the material, said apparatus comprising
A tobacco bulk curing system constructed so as to permit recovery and reuse of the heat utilized in the curing operation, said tobacco bulk curing system comprising
A tobacco bulk curing system constructed so as to permit recovery and reuse of the heat utilized in the curing operation said tobacco bulk curing system comprising
A method for more econmically drying a moisture-containing material, such as tobacco, by a flow of heated air, said method comprising
In a method for curing tobacco in which air, under controlled conditions of temperature and humidity, is directed in a recirculating flow path through a batch of tobacco leaves disposed in a curing chamber, with the air being heated as necessary by a furnace, and with the humidity conditions in the curing chamber being controlled by selectively admitting fresh air to the recirculating flow of air through the curing chamber while discharging exhaust air, the combination therewith of an improvement characterized by substantially reducing the fuel costs for curing the tobacco, said improvement comprising carrying out said curing method concurrently for a series of batches of tobacco in respective individual curing chambers, with the curing schedules for the respective batches of tobacco being staggered timewise so that the batches are at different stages of cure and at different conditions of temperature and humidity at any given time, collecting and combining the flows of heated exhaust air discharged from the respective curing chambers and transferring heat therefrom to a stream of incoming fresh air to thereby preheat the fresh air, and supplying the thus preheated stream of fresh air to a least one of the respective curing chambers.
In a method for curing tobacco in which air, under controlled conditions of temperature and humidity, is directed in a recirculating flow path through a batch of tobacco leaves disposed in a curing chamber, with the air being heated as necessary by a furnace, and with the humidity conditions in the curing chamber being controlled by selectively admitting fresh air to the recirculating flow of air through the curing chamber while discharging exhaust air, the combination therewith of an improvement characterized by substantially reducing the fuel costs for curing the tobacco, said improvement comprising carrying out said curing method concurrently for a series of batches of tobacco in respective individual curing chambers, while selectively admitting fresh air to the respective curing chambers in response to the wet bulb temperature in the individual curing chambers so as to maintain a predetermined substantially uniform wet bulb temperature in each curing chamber, collecting and combining the flows of heated exhaust air discharged from the respective curing chambers and transferring heat therefrom to a stream of incoming fresh air to thereby preheat the fresh air, and supplying the thus preheated stream of fresh air to at least one of the respective curing chambers.
Dependencies are inferred from the claim text.