In fields such as lithium-battery research and development, solid-state battery material preparation, and organic synthesis, many active materials readily react with water and oxygen in the air, directly causing sample failure and distorted experimental data. As a core piece of equipment for inert-atmosphere control, a glovebox can create an anhydrous and oxygen-free workspace with water and oxygen contents below 1 ppm inside a sealed chamber, providing a safe operating environment for handling air-sensitive materials. Mikrouna, as a representative domestic glovebox manufacturer, achieves long-term and stable low water-and-oxygen conditions through the coordinated operation of four major systems: the sealed chamber, gas circulation purification, automatic pressure control, and material transfer through the antechamber.

1. Sealed Chamber: The Physical Basis for Isolating External Air

To maintain an anhydrous and oxygen-free environment, the first requirement is to prevent external air from entering the chamber. The main chamber of the Mikrouna glovebox is made of 304 stainless steel, with weld seams inspected by nondestructive testing. The viewing window uses an O-ring vacuum-flange seal, and the chamber leakage rate is controlled at 0.0006 vol%/h, reducing the risk of gas leakage at the hardware level.

The operating ports are equipped with butyl-rubber gloves. Operators perform experiments inside the chamber through the gloves without opening the main chamber.

The entire Mikrouna glovebox chamber is equipped with annular O-ring seals embedded in an integral annular groove. The seals have no gaps, providing high sealing reliability. Once the seal is damaged, external air continuously enters the chamber; even if the purification system operates at full capacity, it is difficult to maintain low water-and-oxygen levels. A complete sealed chamber and gap-free sealing method are therefore important prerequisites for achieving an anhydrous and oxygen-free environment.

2. Circulation Purification Unit: A Key Module for Removing Water and Oxygen

Sealing can only block external air. Residual moisture and oxygen inside the chamber, as well as moisture and oxygen released by materials, must be continuously removed by the gas circulation purification system. This is also the glovebox's core functional unit.

The chamber is filled with high-purity argon or nitrogen. A circulation fan drives the inert gas to flow in a closed loop between the chamber and the purification column. Two types of adsorbent materials are loaded inside the purification column: copper-based catalyst removes oxygen, while molecular sieves adsorb water vapor. As the gas continuously passes through the purification column, moisture and oxygen are captured, and the purified inert gas returns to the chamber. Repeated circulation continuously lowers the water and oxygen concentration inside the chamber, ultimately achieving an ultraclean environment with water and oxygen below 1ppm.

The adsorbent materials gradually become saturated. The Mikrouna glovebox is equipped with a PLC-controlled automatic regeneration system, which requires no manual disassembly. By heating and introducing a hydrogen-containing mixed gas, the water and oxygen components adsorbed in the purification column are desorbed and discharged, restoring the adsorbent materials' ability to remove water and oxygen. The equipment can therefore be used for long-term circulation, reducing consumable replacement costs.

3. Automatic Pressure Control to Prevent Air Backflow

The inside of a glovebox is not evacuated to a vacuum. Instead, the system continuously maintains a slightly positive pressure, generally controlled at +5 to +10 mbar. Because the pressure inside the chamber is slightly higher than atmospheric pressure, even if tiny gaps exist, inert gas flows outward, preventing external air from flowing back into the chamber.

The glovebox is equipped with pressure sensors and solenoid valves operating in coordination. If the pressure is too high, the system automatically vents to relieve pressure; if the pressure is too low, it automatically supplies high-purity protective gas. The adjustment process is fully automated. If the pressure continues to decrease, the system issues an alarm, prompting the operator to check whether there are leaks in the seals, gloves, or valves. The chamber is also equipped with water and oxygen sensors for real-time online monitoring of the internal atmosphere, allowing operators to directly monitor chamber conditions.

4. Antechamber: Transferring Materials Without Disrupting the Internal Atmosphere

When experimental materials or tools need to enter or leave the chamber, the main chamber door must never be opened directly; otherwise, a large amount of air would rush in and completely disrupt the anhydrous and oxygen-free environment. The antechamber is a structure specifically used for transferring materials. It consists of large and small chambers that connect the external environment with the main chamber. The two doors are interlocked and cannot be opened simultaneously.

Standard operating procedure: place the material in the antechamber, close the outer door, use a vacuum pump to remove the air inside the chamber, then fill it with inert gas. Repeat vacuum evacuation and gas filling several times to displace the air completely. Then open the inner chamber door and transfer the material into the main chamber. This procedure enables safe material transfer while minimizing disturbance to the inert atmosphere inside the main chamber. Materials entering the chamber should also be dried and treated in advance to remove water and oxygen, preventing moisture carried by the materials from consuming the adsorption capacity of the purification column.

 5. Applications and Operating Considerations

Gloveboxes are widely used for handling sensitive materials such as lithium metal, solid-state electrolytes, and organometallic reagents.

Mikrouna gloveboxes can be expanded modularly according to requirements and adapted to different scenarios ranging from laboratory-scale experiments to industrial applications. They can integrate supporting equipment such as battery packaging machines, balances, and hot/cold stages to form an integrated workstation.

In actual use, common causes of excessive water and oxygen include aged or damaged gloves, failed seals, insufficient antechamber purge cycles, moisture carried by materials, and purification columns requiring regeneration. Mikrouna recommends routine leak inspection and maintenance of the glovebox to ensure that it can maintain an anhydrous and oxygen-free environment stably over the long term.