Open type vacuum tube furnace is a device used for high-temperature heating treatment, especially suitable for experiments and production processes that require vacuum or specific atmosphere. Its working principle mainly includes the following aspects:

1、 Heating principle

The core of an open vacuum tube furnace is the heating element, which commonly includes silicon molybdenum rods, silicon carbide rods, and molybdenum wires. These heating elements generate high-temperature heat energy through resistance heating. When current passes through the heating element, the element heats up due to resistance and conducts the heat to the furnace tube and sample.

2、 Vacuum system

The vacuum system is an important component of an open type vacuum tube furnace, usually consisting of a vacuum pump, vacuum valves, and vacuum pipelines. The working process is as follows:

Vacuuming: Start the vacuum pump and extract the gas inside the furnace tube through the vacuum pipeline and valve, creating a high vacuum environment. In a high vacuum environment, the number of gas molecules is significantly reduced, reducing the oxidation and contamination of the sample, making it suitable for oxygen sensitive materials and reactions.

Maintain vacuum: After reaching the set vacuum level, close the vacuum valve to maintain the vacuum state inside the furnace tube. Throughout the heating process, the vacuum system will continue to operate to maintain a stable vacuum environment.

3、 Atmosphere control

In some applications, heating treatment is required under specific atmospheres such as nitrogen, argon, hydrogen, etc. The open vacuum tube furnace achieves this through an atmosphere control system:

Gas introduction: After vacuuming, the required gas is introduced into the furnace tube through an atmosphere control system. The flow rate and pressure of gas are regulated by gas flow controllers and regulating valves to ensure the stability and consistency of the atmosphere.

Atmosphere maintenance: Throughout the heating process, the atmosphere control system continuously supplies gas to maintain a constant gas environment inside the furnace tube to meet different experimental and production needs.

4、 Temperature control

The temperature control system is a key component of an open vacuum tube furnace, typically consisting of a temperature controller, thermocouple, and temperature sensor

Temperature measurement: Thermocouples or temperature sensors are installed inside the furnace tube or near the sample to monitor the temperature in real time and transmit the temperature signal to the temperature controller.

Temperature regulation: The temperature controller controls the current of the heating element through PID regulation algorithm based on the set temperature program and real-time measured temperature, accurately adjusts the heating power, and ensures that the temperature is stable near the set value.

5、 Sample processing

The samples are placed on the sample rack inside the furnace tube, and the open design makes sample loading and unloading very convenient. During the heating process, the sample is processed at high temperature and in a specific atmosphere or vacuum environment to achieve experimental or production purposes.

6、 Cooling process

After the heating process is completed, cooling is usually required:

Natural cooling: Turn off the heating element to allow the furnace tube and sample to cool naturally, suitable for samples without strict cooling rate requirements.

Rapid cooling: When rapid cooling is required, the cooling process can be accelerated by introducing cooling gas (such as nitrogen) or a water cooling system to protect sample characteristics or facilitate rapid turnover.

7、 Conclusion

The open type vacuum tube furnace achieves sample processing under high temperature, vacuum, or specific atmosphere conditions through a precise heating system, stable vacuum and atmosphere control, and temperature regulation. This type of equipment is widely used in fields such as materials science, chemical synthesis, physics research, metallurgy, etc., and can meet various complex experimental and production needs.