Can the lifting bell jar furnace be ventilated with gas?

The lifting bell jar furnace can be filled with gas, and its gas function is mainly achieved through a protective gas system. Its core function is to prevent material oxidation at high temperatures while meeting specific process requirements. The following is a specific analysis:

1. Core design of gas function
Protective gas system
Lift type bell jar furnaces are usually equipped with independent protective gas systems, which support the introduction of high-purity nitrogen, hydrogen, argon, or nitrogen hydrogen mixed gases and other inert/reducing gases. Gas enters the furnace through the inlet on the bottom or side wall, forming a protective atmosphere during the heating process, isolating oxygen and preventing material oxidation. For example, in metal bright annealing, hydrogen can reduce surface oxides and maintain material brightness; In ceramic sintering, nitrogen can prevent the material from reacting with oxygen.
Exhaust gas discharge design
The furnace top is equipped with exhaust ports, and the exhaust rate is controlled by manual or automatic valves to ensure timely discharge of waste gas (such as impurities evaporated during sintering) and maintain a stable atmosphere inside the furnace. Some models are also equipped with exhaust gas collection devices to prevent harmful gas leaks.

2. Process advantages of gas function
Prevent oxidation and improve material performance
At high temperatures, metals such as copper and stainless steel are prone to react with oxygen to form oxides, leading to surface blackening and decreased conductivity. After the introduction of protective gas, the material is annealed in an oxygen free environment, which can maintain high conductivity, bright surface, and corrosion resistance. For example, the electrical resistivity of copper material decreases after annealing, making it suitable for the manufacturing of wires and cables.
Support special process requirements
Reduction atmosphere sintering: In ceramic or hard alloy sintering, introducing hydrogen gas can reduce oxide impurities in the material and improve purity.
Carbon control process: In carburizing treatment, introducing carbon containing gases such as methane can control the surface carbon content of the material and enhance its hardness.
Active metal processing: Metals such as zirconium and hafnium are prone to combustion in air and need to be sintered in vacuum or inert gas. The lifting bell jar furnace can achieve such extreme conditions through a gas system.

3. Typical application scenarios
Bright annealing of metals
Copper and copper alloys, stainless steel, electrical steel and other materials are annealed in a protective gas to eliminate internal stress, soften the metal, and maintain surface brightness. For example, after solid solution treatment, the corrosion resistance of austenitic stainless steel is significantly improved.
Ceramics and Hard Alloy Sintering
Aluminum oxide ceramics, silicon nitride ceramics, and tungsten cobalt hard alloys are sintered in inert gas to avoid performance degradation caused by oxidation. Some furnace models also support vacuum gas switching to meet different material requirements.
Powder metallurgy pretreatment
During the powder baking stage, introducing gas can remove volatile components such as sulfur and lead, preventing corrosion of the furnace or heating elements during subsequent sintering.

4. Technical Implementation and Security
Sealing design
The bell jar, furnace table, and inner liner structure are precisely matched (such as flange connections and sealing rings) to ensure that gas does not leak. Some models are equipped with vacuum pumps, which evacuate before introducing protective gas to further remove oxygen.
security control
Gas flow monitoring: Accurately adjust the intake volume through a float flowmeter or mass flow controller.
Alarm and protection: The functions of over temperature, disconnection, and overcurrent protection can prevent safety accidents caused by gas leakage or abnormal furnace temperature.
Exhaust gas treatment: The overhead exhaust gas collection device can comprehensively collect exhaust gas and avoid pollution.