Shandong Zhongjie Special Equipment specializes in products such as fuel (gas) boilers, organic heat carrier boilers, biomass boilers, waste heat boilers, and other boiler products; vacuum insulation cryogenic pressure vessels like LNG tanks, oxygen/nitrogen/argon tanks, and CO2 tanks; pressure vessel products including denitrification engineering equipment, heat storage equipment, and complete chemical equipment sets; central air conditioning and HVAC equipment such as ground (water) source heat pumps, air-source units, water-cooled screw units, and air-cooled modular units. Planned products include large-scale energy centers, LNG transport vehicles, LNG tank containers, and other green energy equipment.
The primary reason for pre-cooling a liquid oxygen tank before use is to lower the tank's internal temperature to below the boiling point of liquid oxygen, enabling the conversion of oxygen into a liquid state.
The boiling point of liquid oxygen is -183°C; at room temperature, oxygen exists as a gas. Liquid oxygen tanks require cooling the oxygen below its boiling point to convert it into a liquid for storage and supply.
The pre-cooling process typically includes the following steps:
Clean Storage Tank: First, the tank must be thoroughly cleaned to ensure there are no impurities or contaminants inside, in order to avoid affecting liquid oxygen.
Emptying and Exhausting: To evacuate the gas inside the storage tank and expel it through the exhaust system to reduce the gas content within the tank.
Add Liquid Nitrogen: Inject liquid nitrogen into the tank, which can rapidly cool the air inside and the walls, thereby reducing the tank's temperature.
Cooling Off: The liquid nitrogen inside the storage tank will gradually lower the tank's temperature through the process of heat conduction, until it falls below the boiling point of liquid oxygen.
The purpose of pre-cooling is to ensure that the temperature inside the storage tank is low enough to meet the storage and supply requirements of liquid oxygen. Pre-cooling can reduce the evaporation and loss of liquid oxygen, and also helps maintain the safety and stability of the tank.

The cooling process and precautions for liquid argon cylinders are as follows:
Cooling Process Analysis:
Ensure cleanliness of the cylinder: Before cooling the liquid argon cylinder, ensure the interior is clean and free of impurities and contaminants. Use suitable cleaning agents for washing and rinse thoroughly.
Drainage and Exhaust: Empty the gas inside the tank and expel it through the exhaust system to reduce the gas content within the tank.
Add Liquid Nitrogen: Inject liquid nitrogen into the tank, which can rapidly cool the air and walls inside the tank due to its low temperature, thereby reducing the tank's temperature.
Waiting for Cooling: Liquid nitrogen will gradually lower the temperature inside the tank through the process of heat conduction until it reaches the required low temperature.
Cautionary Notes:
Safety Protection: Necessary safety precautions must be taken during the cooling process of liquid argon tanks. Liquid argon has low temperatures and high flammability, so operators should wear protective suits, gloves, and other personal protective equipment to ensure safe operation.
Fire Prevention Measures: Liquid argon is highly flammable; hence, during the cooling process of the liquid argon tank, it is crucial to ensure there are no ignition sources in the surrounding environment and appropriate fire extinguishing equipment is available.
Temperature Control: During the cooling process of the liquid argon cylinder, it is necessary to control the cylinder's temperature to prevent overcooling or insufficient cooling. Temperature sensors and temperature control systems can be used to monitor and control the cylinder's temperature.
Insulation and Heat Retention: Liquid argon tanks are typically constructed with double or multi-layered structures, filled with insulating material in the middle to minimize heat transfer and evaporation of the liquid argon. Ensure the integrity and good insulating properties of the insulating layer.

Liquid oxygen storage tanks may deform during use. The following are common deformation defects in liquid oxygen storage tanks:
Elastic deformation: Liquid oxygen tanks may experience elastic deformation when subjected to external pressure or temperature changes. This deformation is typically reversible, meaning the tank will return to its original shape once the external pressure is removed or the temperature returns to normal.
Plastic Deformation: When a liquid oxygen tank is subjected to significant external force or pressure, it may undergo plastic deformation. This deformation is irreversible, and the tank cannot return to its original shape. Plastic deformation can cause changes in the tank's shape, such as dents or warping.
Hot Deformation: Liquid oxygen tanks may experience hot deformation when subjected to high temperatures or temperature changes. Hot deformation can cause the tank to change shape, expand, or contract.
Cold deformation: Liquid oxygen tanks may experience cold deformation when subjected to low temperatures or temperature changes. Cold deformation can cause the tank to change shape, contract, or crack, among other issues.
These deformation defects may affect the structural integrity and safety of liquid oxygen storage tanks. Therefore, regular inspections and assessments of the deformation conditions of liquid oxygen storage tanks are crucial to ensure their normal operation and safe use. If deformation defects in the tanks are detected, prompt repair or replacement measures should be taken to avoid further damage and safety risks.

Liquid nitrogen storage tanks feature the following characteristics during the construction process:
Low-Temperature Construction: The construction of liquid nitrogen tanks must be carried out in low-temperature environments, as liquid nitrogen has a low boiling point of approximately -196 degrees Celsius. Construction personnel must take appropriate protective measures, such as wearing thermal protective clothing and gloves, to protect themselves from low-temperature injuries.
Welding Technology: A significant amount of welding work is required during the manufacturing process of liquid nitrogen tanks, including the connections of tank wall panels, bottom plates, top plates, and welds. Welding technology is crucial for the quality and safety of the tanks, necessitating the use of appropriate welding methods and materials to ensure the strength and密封性 of the welds.
Insulation Layer Installation: Liquid nitrogen tanks must have excellent insulation properties to minimize heat conduction and retain the low temperature state of liquid nitrogen. The installation of the insulation layer requires materials such as polyester foam and glass wool, ensuring the thickness and quality of the insulation layer.
Proper installation steps for liquid nitrogen tanks are as follows:
Site Preparation: Select an appropriate site for tank installation, ensuring it is level, sturdy, and has adequate load-bearing capacity. The site should be kept away from flammable, explosive materials, and other hazards.
Foundation Construction: The foundation will be constructed based on the tank's dimensions and weight, including excavation of the foundation pit and pouring concrete. The design and construction of the foundation must comply with relevant standards and specifications.
Tank Installation: Transport the tank to the site and perform a vertical installation. Appropriate lifting equipment and safety measures must be used during the installation process to ensure the stability and safety of the tank.
Pipe Connections: Connect the tank to the relevant pipeline system as required, including intake pipes, exhaust pipes, and liquid supply pipes. Sealing and testing must be performed during the connection process to ensure pipeline safety.
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