Clothes dryer

Abstract

A clothes dryer having a preheating unit preheating drawn air is provided. The clothes dryer includes a main body, a drying tub rotatably mounted to receive an object to be dried, and a hot air duct supplying hot air into the drying tub. The hot air duct includes a heating unit heating drawn air, and a hot air supply unit connecting the heating unit with the drying tub, thereby forming a path for heated air. The heating unit includes a first heating unit having a heater part generating heat, and a second heating unit surrounding an entrance and outer walls of the first heating unit, thereby forming a path for the air flowing to the first heating unit. The second heating unit includes one or more preheating fins formed on the first heating unit to contact the air flowing in the second heating unit.

1 . A clothes dryer comprising:
 a main body;   a drying tub rotatably mounted to receive an object to be dried; and   a hot air duct supplying hot air into the drying tub,   wherein the hot air duct includes a heating unit heating drawn air, and a hot air supply unit connecting the heating unit with the drying tub, thereby forming a path for heated air, and   the heating unit includes a first heating unit having a heater part disposed therein to generate heat, and a second heating unit surrounding an entrance and outer walls of the first heating unit, thereby forming a path for the air flowing to the first heating unit.   
     
     
         2 . The clothes dryer according to  claim 1 , wherein the second heating unit comprises a preheating fin formed on one of the outer walls of the first heating unit to contact the air flowing in the second heating unit. 
     
     
         3 . The clothes dryer according to  claim 2 , further comprising a plurality of the preheating fins, wherein the preheating fins are arranged parallel with one another in a length direction of the first heating unit. 
     
     
         4 . The clothes dryer according to  claim 2 , further comprising a plurality of the preheating fins, wherein the preheating fins are slanted with respect to a length direction of the first heating unit. 
     
     
         5 . The clothes dryer according to  claim 4 , wherein the preheating fins are slanted by about 3°˜7° with respect to the length direction of the first heating unit. 
     
     
         6 . The clothes dryer according to  claim 1 , wherein the second heating unit comprises a main body and a flow loss reduction part to reduce loss of flow during air suction, and
 the flow loss reduction part comprises an air suction part having a diameter larger than a diameter of the main body of the second heating unit.   
     
     
         7 . The clothes dryer according to  claim 1 , wherein the heating unit further comprises a galvanized steel sheet. 
     
     
         8 . The clothes dryer according to  claim 2 , wherein the preheating fins comprise at least one of a galvanized steel sheet, aluminum, and copper. 
     
     
         9 . The clothes dryer according to  claim 2 , wherein the preheating fins are arranged at constant intervals. 
     
     
         10 . The clothes dryer according to  claim 1 , wherein the heating unit comprises a heater plate formed across an inside of the first heating unit, a nichrome wire emitting heat by supplied electricity, and a ceramic member fixing the nichrome wire to the heater plate. 
     
     
         11 . A clothes dryer comprising:
 a main body;   a drying tub rotatably mounted to receive an object to be dried; and   a hot air duct supplying hot air into the drying tub,   wherein the hot air duct includes a heating unit having a heater part to heat air drawn thereinto to provide the hot air, and   the heating unit includes a main heating unit that heats the drawn air using the heat of the heater part, and a preheating unit that forms a path for the air flowing to the main heating unit and heats the air using the heat of the main heating unit.   
     
     
         12 . The clothes dryer according to  claim 11 , wherein the preheating unit is disposed on the air path that guides the air flowing to the main heating unit. 
     
     
         13 . The clothes dryer according to  claim 11 , wherein the air path is configured so that the air guided to the preheating unit is reversed and guided to the main heating unit. 
     
     
         14 . The clothes dryer according to  claim 13 , wherein the air path includes a body of the main heating unit having a pipe form, and the preheating unit having a pipe form surrounding the main heating unit. 
     
     
         15 . The clothes dryer according to  claim 14 , wherein ends of the body of the main heating unit are opened,
 one end of the preheating unit being closed while another end of the preheating unit being opened to form an entrance for an airflow, and   the air is guided in through the entrance of the preheating unit, reversed by the blocked end, and then guided into the main heating unit.   
     
     
         16 . The clothes dryer according to  claim 11 , wherein the preheating unit comprises a preheating fin formed on an outside of the main heating unit so that the heat of the main heating unit is transmitted to the preheating unit. 
     
     
         17 . A clothes dryer including a hot air duct that supplies hot air, wherein
 the hot air duct comprises a heating unit to heat air drawn therein, and   the heating unit comprises a first heating unit directly heating the air flowing therein, and a second heating unit disposed adjacent to the first heating unit, thereby forming an air path guiding air in the opposite direction to the air flowing in the first heating unit, the second heating unit indirectly heating the air flowing into the first heating unit using the heat of the first heating unit.   
     
     
         18 . The clothes dryer according to  claim 17 , wherein the first heating unit comprises one or more preheating fins formed on outer walls thereof to contact the air flowing in the second heating unit. 
     
     
         19 . A clothes dryer comprising:
 a main body;   a heating unit heating drawn air;   a hot air supply unit connected to an end of the heating unit, thereby forming a path for the heated air;   a drying tub connected to the hot air supply unit and structured to receive an object to be dried;   a ventilation device circulating the air; and   an exhaust duct guiding the air exhausted from the drying tub to the outside of the main body,   wherein the heating unit comprises a first heating unit connected to the hot air supply unit and equipped with a heater part that generates heat therein, and a second heating unit forming an air path in which air flows in contact with outer walls of the first heating unit and guiding the air to the first heating unit.   
     
     
         20 . The clothes dryer according to  claim 19 , wherein the second heating unit comprises a preheating fin formed on the outer walls of the first heating unit to enhance heating of the air flowing in the second heating unit.