Can a customized experimental muffle furnace pass gas?

Whether the customized experimental muffle furnace can pass gas depends on the type of furnace body:

Ordinary box type muffle furnace: usually designed as an open or simple sealed structure, it is not recommended to directly introduce flammable gases such as hydrogen. Insufficient sealing may lead to hydrogen leakage, which can easily cause explosions when mixed with air at high temperatures. But inert gases such as nitrogen can be introduced for protective annealing or oxidation prevention, but it is necessary to first evacuate and replace the air to ensure a reducing atmosphere.
Tube type muffle furnace: using quartz or metal tubes as the furnace, equipped with gas inlet and outlet and sealing devices, can safely introduce various gases, including hydrogen, nitrogen, argon, etc. Its sealing structure can effectively prevent gas leakage, and the gas flow path is controllable, suitable for scenarios such as catalytic reactions and reduction experiments that require specific atmospheres.
Vacuum box muffle furnace: Combining vacuum technology with atmosphere control function, impurities can be removed by vacuuming first, and then inert gases such as nitrogen and argon can be introduced to create a pure and oxygen free environment for experiments. Some models also support hydrogen gas injection, but require explosion-proof devices and strict safety monitoring systems.
Experimental atmosphere electric furnace: Upgraded from the muffle furnace, capable of introducing various gases such as oxygen, nitrogen, argon, hydrogen, etc., and equipped with a precision flow control system. The furnace material (such as quartz glass tube) and heating element (such as silicon molybdenum rod) can withstand high temperature and gas corrosion, making it suitable for complex experiments such as metal heat treatment and material synthesis.

Key precautions when passing gas:
Gas selection and safety:
Due to its wide explosion limit (4% -75% volume concentration), hydrogen gas is only suitable for use in well sealed tube furnaces or specialized atmosphere furnaces, and must be equipped with a hydrogen concentration monitor and explosion-proof device.
Inert gases such as nitrogen and argon have high safety, but purity must be ensured (such as high-purity nitrogen ≥ 99.999%) to avoid impurities interfering with the experiment.
Equipment sealing and leak detection:
Before introducing gas, it is necessary to check the sealing of the furnace body, such as the connection between the quartz tube and flange of the tube furnace and the door seal of the box furnace. Soap water can be used for leak detection to ensure that there is no leakage before introducing gas.
Gas flow and pressure control:
Adjust the gas flow rate according to experimental requirements (such as 20ml/min for hydrogen and 50-100mL/min for nitrogen) to avoid excessive flow causing high furnace pressure or airflow disturbance affecting temperature uniformity.
Some furnace types need to be evacuated to -0.1MPa (pointer to the end) before introducing gas to eliminate air.
Exhaust gas treatment and safety protection:
The tail gas of toxic or flammable gases (such as hydrogen and chlorine) needs to be treated through alkali absorption towers, combustion devices, etc. before being discharged.
Experimental personnel need to wear protective equipment such as gas masks and heat-resistant gloves, and stay away from poorly ventilated areas.
Operating standards and emergency measures:
Before introducing hydrogen gas, nitrogen gas should be introduced to replace the air inside the furnace for at least 10 minutes, and then the hydrogen flow rate should be gradually adjusted.
During the heating process, it is strictly prohibited to open the furnace door to prevent air from entering and causing an explosion; After the experiment, the gas valve should be closed first, and then the heating should be stopped.