A roasting apparatus for heating an object, comprising:
- a roasting chamber part which includes a cylindrical roasting chamber, in which an object is stirred and which extends in a vertical direction, and a rotary stirring part rotated to stir the object accommodated in the roasting chamber, wherein the rotary stirring part is rotated about a stirring axis formed in the vertical direction;
- a casing unit configured to surround the roasting chamber part;
- a heat source part including a first heat source part configured to provide radiant heat to the roasting chamber part;
- and
- a radiant temperature measurement unit configured to measure a temperature of the roasting chamber or the object and a chamber outer space temperature of a chamber outer space between the casing unit and the roasting chamber part on the basis of infrared rays emitted from an inner surface of the roasting chamber part or a surface of the object, which is heated by the heat source part,
- wherein a preheating operation is performed until the chamber inner temperature of the roasting chamber and the chamber outer space temperature reach a preset reference chamber inner temperature and a preset reference chamber outer space temperature;
- wherein the radiant temperature measurement unit is disposed in an upper unit disposed above the roasting chamber and faces an internal space of the roasting chamber;
- and
- the radiant temperature measurement unit includes:
- a sensing part configured to measure the temperature of the object on the basis of the infrared rays and face the roasting chamber;
- an outer space temperature measurement unit configured to measure the chamber outer space temperature of the chamber outer space;
- and a board on which the sensing part and the outer space temperature measurement unit are mounted;
- wherein a measured temperature Tmeasure of the roasting chamber or the object, which is measured by the radiant temperature measurement unit, is corrected on the basis of a chamber outer space temperature Toutside, and then a real temperature of the roasting chamber or the object is calculated;
- a measurement hole is formed to pass through the upper unit and communicates with the roasting chamber;
- and
- the radiant temperature measurement unit includes:
- the sensing part configured to measure the temperature of the object on the basis of the infrared rays;
- a measuring unit body which is disposed on an upper surface of the upper unit and in which a body side through hole communicating with the roasting chamber is formed;
- the board which is disposed on one side of the measuring unit body and on which the sensing part is mounted;
- and a filter part which is disposed in front of the sensing part and through which light of a preset wavelength band passes,
- wherein the body side through hole communicates with the measurement hole, and the sensing part is positioned in the body side through hole,
- one surface of the filter part faces the sensing part, and the other surface thereof directly faces the roasting chamber, and
- emissivity of the filter part is varied according to a temperature;
- wherein the real temperature Treal is calculated in consideration of an emissivity change of the filter part on the basis of an outside temperature Toutside at the measured temperature Tmeasure;
- and
- the real temperature Treal and the measured temperature Tmeasure satisfy the following relational expression:
- T
- real
- ,
- k
- =
- T
- measure
- ,
- k
- -
- (
- E
- 0
- +
- T
- outside
- ,
- c
- ×
- e
- )
- ×
- T
- outside
- ,
- k
- (
- 1
- -
- E
- 0
- )
- -
- T
- outside
- ,
- c
- ×
- e
- ,
- wherein Treal,k denotes a corrected real temperature of the object (based on absolute temperature), Tmeasure,k denotes a measured temperature of the object measured by the sensing part (based on absolute temperature), Toutside,c denotes an outside temperature of the roasting chamber (based on degrees Celsius), Toutside,k denotes an outside temperature of the roasting chamber (based on absolute temperature), E0 denotes emissivity of the filter part at zero degrees Celsius, and e denotes variance in emissivity per absolute temperature 1 degree (or 1 degree Celsius) of the filter part.