Dryer and method for operating a dryer
A disclosed dryer includes a receptacle configured to contain material to be dried, an air duct configured to route recirculating air and/or fresh air to the receptacle, a heating device configured to heat the recirculating air, and at least one sensor. The sensor is configured to determine a relative humidity and/or temperature, and the air duct includes at least one adjusting element configured to modify a portion of recirculating air routed to the receptacle. The dryer further includes a control or regulating device configured to control or regulate the portion of recirculating air routed to the receptacle and/or a heating capacity of the heating device during a drying process. A disclosed method includes controlling a portion of recirculating air routed to the receptacle and/or a heating capacity of the heating device. Further, a mixture of recirculating air and fresh air are varied during heat-up, drying, and cool-down phases.
1. A dryer comprising:
a receptacle configured to contain material to be dried;
an air duct configured to route recirculating air and/or fresh air to the receptacle;
a heating device configured to heat the recirculating air;
at least one sensor configured to determine a relative humidity and/or temperature, wherein the air duct comprises at least one adjusting element configured to modify a portion of recirculating air routed to the receptacle; and
a control or regulating device configured to control or regulate the portion of recirculating air routed to the receptacle and/or a heating capacity of the heating device during a drying process, wherein the control or regulating device is further configured to control the adjusting element to:
route, during a heat-up phase, a first portion of recirculating air and a second portion of fresh air to the receptacle, wherein the first portion is a high portion and the second portion is a low portion;
route, during a cool-down phase, the first portion of recirculating air and the second portion of fresh air to the receptacle, wherein the first portion is a low portion and the second portion is a high portion;
reduce, during a drying phase, the first portion of recirculating air, based on a measured relative exhaust air humidity and/or based on a heating capacity of the heating device.
2. The dryer according to claim 1 , wherein the adjusting element comprises a ventilation flap and/or a recirculating air blower.
3. The dryer according to claim 2 , wherein a position of the ventilation flap and/or an output of the recirculating air blower is continuously adjustable.
4. The dryer according to claim 1 , wherein the sensor is configured to determine a relative humidity of exhaust air discharged from the receptacle.
5. The dryer according to claim 1 , wherein the sensor is configured to determine a surface temperature of the material to be dried and/or to determine an input air temperature and/or an output air temperature.
6. The dryer according to claim 4 , wherein the control or regulating device controls the adjusting element to adjust the portion of recirculating air based on a determined relative exhaust air humidity.
7. The dryer according to claim 5 , wherein the control or regulating device controls the adjusting element to adjust the portion of recirculating air based on a determined surface temperature of the material to be dried.
8. The dryer according to claim 4 , wherein the control or regulating device controls the heating capacity of the heating device based on a determined relative exhaust air humidity.
9. The dryer according to claim 1 , wherein the receptacle further comprises:
a heating device configured to heat the material to be dried;
a drying device configured to dry the material to be dried;
a cooling device configured to cool the material to be dried; and
a transport device configured to transport the material to be dried between at least at least a first and a second one of the heating device, the drying device, and the cooling device,
wherein the heating device, the drying device, and the cooling device are positioned one after another along a direction in which material to be dried is transported.
10. The dryer according to claim 9 , wherein the air duct is configured to provide the recirculating air as exhaust air from at least a first one to a second one of the heating device, the drying device, and the cooling device.
11. The dryer according to claim 2 , wherein the receptacle is configured as a rotating drum, and
wherein the control or regulating device controls or regulates the portion of recirculating air routed to the receptacle and/or the heating capacity of the heating device based on one or more parameters, the parameters including:
a type of material to be dried;
a heater temperature;
a residual moisture of the material to be dried;
a starting moisture of the material to be dried;
a load quantity of material to be dried;
a filling ratio of the receptacle;
an air temperature or relative humidity;
a blower capacity; and
a motion of the rotating drum.
12. A method of operating a dryer, the dryer comprising a receptacle configured to contain a material to be dried, an air duct configured to route recirculating air and/or fresh air to the receptacle, a heating device configured to heat the recirculating air, a control or regulating device, and at least one sensor configured to determine relative humidity and/or temperature, wherein the air duct comprises at least one adjusting element configured to modify a portion of recirculating air routed to the receptacle, the method comprising:
controlling during a drying process, via the control or regulating device, a portion of recirculating air routed to the receptacle and/or a heating capacity of the heating device, wherein controlling includes:
routing, during a heat-up phase, a first portion of recirculating air and a second portion of fresh air to the receptacle, wherein the first portion is a high portion and the second portion is a low portion;
routing, during a cool-down phase, the first portion of recirculating air and the second portion of fresh air to the receptacle, wherein the first portion is a low portion and the second portion is a high portion;
measuring a relative exhaust air humidity;
reducing, during a drying phase, the first portion of recirculating air, based on a measured relative exhaust air humidity and/or based on a heating capacity of the heating device.
13. The method according to claim 12 , further comprising:
wherein during the heat-up phase
the first portion of recirculating air includes 90% to 100% recirculating air, and
the second portion of fresh air includes 0% to 10% fresh air.
14. The method according to claim 12 ,
wherein during the cool-down phase
the first portion of recirculating air includes 0% to 10% recirculating air, and
the second portion of fresh air includes 90% to 100% fresh air.
15. The method according to claim 12 , further comprising:
controlling a duration of the drying phase and/or the reduction in the first portion of recirculating air based on at least one external parameter.
16. The method according to claim 15 , wherein the receptacle is configured as a rotating drum, and wherein the at least one external parameter is chosen from parameters including:
a type of material to be dried;
a heater temperature;
a residual moisture of the material to be dried;
a starting moisture of the material to be dried;
a load quantity of material to be dried;
a filling ratio of the receptacle;
an air temperature or relative humidity;
a blower capacity; and
a motion of the rotating drum.
17. The dryer according to claim 5 , wherein the control or regulating device controls the heating capacity of the heating device based on a determined surface temperature of the material to be dried.