Measurement Method for Temperature Uniformity of Bogie Hearth Furnace

Measurement Method for Temperature Uniformity of Bogie Hearth Furnace

The measurement of bogie hearth furnace temperature uniformity can be carried out using displacement method or multiple thermocouple measurement method. The former uses an assembled thermocouple to move inside the furnace and measure the temperature of each part. This method can only measure a few points on the same line within a plane of the trolley furnace, and cannot measure the temperature of the bogie hearth furnace space, which is limited. Only applicable to furnaces with smaller furnace sizes, which involve placing multiple thermocouples simultaneously inside the furnace to measure a certain space. Due to measuring a complete space and being able to read simultaneously, it can measure furnaces of various shapes and is also suitable for production. The program is as follows:

Raise the bogie hearth furnace temperature to the required temperature according to the conventional procedure and hold for 2-3 hours. Then open the bogie hearth furnace door and place a sufficient number of measuring thermocouples in the designated positions inside the bogie hearth furnace. In order to fix the position of the thermocouple, a frame is usually made based on the size of the chamber. Place the thermocouple together with the frame into the furnace, and start reading after closing the furnace door. The reading should last for a sufficient amount of time to determine the time distribution characteristics of the temperature. After the temperature stabilizes, the reading should continue for at least 30 minutes.

When measuring the temperature uniformity of the trolley furnace, for new and overhauled furnaces, measurements should be taken at their operating temperature and intermediate temperature. For the bogie hearth furnace in use, it can be operated at the commonly used temperature within the range of use, or alternatively at the operating temperature and the commonly used temperature. For furnaces that use sealed tanks for protective gas treatment, it should be carried out within the sealed tank working area. Pay special attention to the difference between the temperature inside the tank and the temperature outside the tank.

The measurement of bogie hearth furnace temperature uniformity can be carried out in an empty furnace, which makes the measurement more convenient; It can also be carried out at the same loading capacity as the production load, making it closer to the actual production. Regardless of the method used, the same requirements must be met.

The measurement of bogie hearth furnace temperature uniformity should select the corresponding armored thermocouple according to the operating temperature.

The measurement readings can be recorded using a multi-point long chart recorder or a DC potentiometer. At present, multi-point long chart recorders are commonly used to obtain continuous temperature recording curves.

After using the bogie hearth furnace for a period of time, its temperature distribution will change. Therefore, measurements should be conducted periodically. The cycle of a general heat treatment furnace is recommended to be six months, and it can also be extended or shortened appropriately according to the situation. Between two cycles, the temperature of a certain point in the bogie hearth furnace chamber of the trolley can be detected in order to timely grasp the changes in bogie hearth furnace temperature uniformity.