Optimization and improvement strategy for well type annealing furnace

In order to ensure the uniformity of furnace temperature and energy-saving efficiency of the well type annealing furnace, the following measures have been taken on the basis of traditional annealing tanks in the selection of furnace lining materials, electric heating elements, vacuum tank fans, thermocouple installation, and temperature control instruments:
1. Electrical control.
In terms of control system, all temperature control instruments are selected with excellent accuracy in temperature control. Through PID adjustment, the temperature control accuracy is ± 1 ℃. At the same time, solid-state relays were used as switching elements to achieve accurate temperature control without contact on/off.
2. Selection of furnace lining materials.
The use of full fiber vacuum negative pressure formed bricks significantly reduces the number of gaps in conventional refractory bricks, reduces long-term use caused by thermal expansion and contraction, resulting in heat loss of the furnace body and uneven furnace temperature. The use of full fiber product bricks also has the advantages of less heat accumulation and heating up, and the traditional lightweight refractory brick structure can save about 25% energy.
3. Strong wind convection.
The installation of a strong convection fully sealed circulating fan on the furnace cover promotes the formation of strong convection in the furnace, forming a dual circulation of furnace gas to ensure that the temperature near the center of the furnace and the shell is close to the same, so that the copper wire center and periphery are heated simultaneously. Compared with traditional annealing vacuum cans, the application of natural convection in the gas flow inside the can forms a distinct optimization of convection efficiency. At the same time, the temperature control thermocouple is directly installed in the well type annealing furnace, and the actual temperature inside the tank is used as the temperature control signal to ensure that the temperature difference inside the tank is small and the temperature uniformity inside the tank is not greater than ± 5 ℃.
4. Zone heating.
The application of resistance strips in electric heating elements enhances the heating efficiency by increasing the heating coefficient by 6% compared to resistance wires. At the same time, different heating powers are distributed in the upper, middle, and lower zones of the furnace for heating and temperature control to ensure uniform temperature.
5. Remove human error.
(1) Using a digital vacuum pressure gauge, the vacuum degree and pressure display are intuitive. Changed the accidental error of the original pointer instrument.
(2) The oxygen analyzer is used to accurately display the value of oxygen content in the tank after vacuum pumping, and to monitor the changes in oxygen content in the tank during actual annealing and cooling processes. Remove all old equipment and rely on the experience of production staff to operate
(3) When the pressure inside the furnace drops to the set lower limit, the system will alarm and automatically inflate to the set upper limit to complete the annealing process using electrical automatic control.
6. Can mouth treatment.
In order to ensure that the temperature inside the well type annealing furnace reaches a uniform temperature difference of no more than ± 5 ℃ between the upper, middle, and lower temperatures outside the tank, two layers of fine sand are used to seal the vacuum tank and furnace mouth to prevent the temperature difference between the upper and lower temperatures caused by the rise of hot gas.