Shandong Zhongjie Special Equipment (formerly Heze Boiler Factory Co., Ltd.) was established in 2001, located at No. 2218 Jinnan Road, Economic and Technological Development Zone, Heze City. With a registered capital of 50 million yuan and total assets of 500 million yuan, the company has 7 business centers: boilers, deep-freezing containers, pressure vessels, central air conditioning, engineering installation, international trade, and Internet of Things. It has three factory sites on Jinnan Road, East Changjiang Road, and Bohai Road, covering a total of 200,000 square meters, with the main workshop spanning 83,000 square meters. It currently employs 710 people, including 247 engineers and technicians and 82 intermediate-level technical personnel. In December 2016, it was recognized as a "High-tech Enterprise" by the Science and Technology Department. In June 2021, it was identified as a "Specialized and New Enterprise in Shandong Province" by the Ministry of Industry and Information Technology. In June 2022, it was recognized as a "Gazelle Enterprise in Shandong Province" and in August 2022, it was identified as a "Specialized and New Small Giant Enterprise" by the Ministry of Industry and Information Technology.
Daily inspection of liquid nitrogen storage tanks primarily includes the following aspects:
Appearance Inspection: Check for any visible damage, deformation, or corrosion on the tank's exterior, including the tank wall, valves, pipelines, and joints.
Sealability Inspection: Check the tank's sealing performance, including inspecting for leaks at valve and pipeline connections, and verifying that the tank's exhaust valve and safety valve are functioning properly.
Pressure Check: Verify that the storage tank's pressure gauge is functioning properly and that the pressure is within the normal range to ensure the tank operates correctly.
Level Check: Inspect the liquid nitrogen tank's level to ensure it remains within the normal range, avoiding issues caused by excessive or insufficient levels.
Insulation Layer Inspection: Check if the insulation layer of the tank is intact, for any signs of damage or detachment, to ensure effective insulation and reduce evaporation losses of liquid nitrogen.
Leak Inspection: Check for signs of liquid nitrogen leakage around the storage tank, including frost, ice, or liquid nitrogen stains on the ground.
Safety Equipment Inspection: Verify that the storage tank's safety equipment, such as leak detectors, alarm systems, and safety valves, are functioning properly to ensure the tank's safety.
Cleaning Inspection: Regularly clean the interior of the tank to remove accumulated impurities and dirt, maintaining the tank's cleanliness and hygiene.
The above lists the daily inspection requirements for liquid nitrogen tanks. The specific inspection items should be adjusted and supplemented based on the tank's model, usage, and relevant regulations. During the inspection process, strictly adhere to the relevant operational procedures and safety operation requirements to ensure the safe operation of the tank.

Safety operation and transportation of liquid oxygen storage tanks should pay attention to the following points:
Safe Usage Instructions:
Tank Selection: Choose liquid oxygen tanks that comply with regulations and standards, ensuring their quality and safety performance.
Tank Installation: Tanks should be installed on a solid foundation to ensure stability. Additionally, good ventilation should be maintained around the tank, and it should be kept away from flammable materials and heat sources.
Sealability Inspection: Regularly check the tank's sealing performance to ensure there are no leakage issues at valve and pipeline connections.
Pressure Control: Tanks should be equipped with pressure gauges and safety valves, with regular inspections and maintenance to ensure pressure remains within safe limits.
Fire Protection Measures: Liquid oxygen contains a high concentration of oxygen, which is highly flammable. Establish fire barriers around storage tanks, prohibit smoking and open flames, and ensure safety.
Electrostatic Protection: During the transportation and use of liquid oxygen, static electricity can cause sparks, increasing the risk of fire. Measures such as using electroconductive materials and anti-static equipment are taken to reduce the accumulation and release of static electricity.
Shipping Precautions:
Transportation Vehicle Selection: Choose transportation vehicles that meet the requirements for liquid oxygen transport, ensuring their safety and sealing.
Loading and Unloading: During the transportation of liquid oxygen, appropriate loading and unloading procedures should be adopted.

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, facilitating the conversion of oxygen into a liquid state.
The boiling point of liquid oxygen is -183°C, and at room temperature, oxygen exists in a gaseous state. To store and supply it, the liquid oxygen tank must cool the oxygen below its boiling point to convert it into a liquid form.
The pre-cooling process typically involves the following steps:
Clean Storage Tank: First, the tank must be thoroughly cleaned to ensure there are no impurities or contaminants inside, to avoid affecting liquid oxygen.
Drainage and Exhausting: To empty 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 storage tank, where its low temperature rapidly cools the air inside and the tank walls, thereby lowering the tank's temperature.
Waiting for cooling: The liquid nitrogen in the tank will gradually lower the temperature inside the tank through the process of heat conduction until it reaches 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 for 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 hydrostatic test of a liquid nitrogen storage tank is a common testing method used to inspect the tank's sealing integrity and pressure resistance. Below are the general steps for the hydrostatic testing of a liquid nitrogen storage tank:
Preparation: Ensure the tank interior is clean and that the tank is empty of gases and liquids. Check the tank's sealing and safety devices for proper operation.
Fill water: Fill the interior of the tank with water, ensuring the water level is above the low water mark. Use a pump or other appropriate methods for filling.
Apply Pressure: Gradually increase the water pressure using a pressure pump or other pressure source until the predetermined test pressure is reached. The test pressure is typically 1.1 times the design working pressure of the tank.
Pressure maintenance: After reaching the test pressure, maintain it for a period (typically 30 minutes to 1 hour) and observe for any abnormal conditions such as leaks or deformation in the tank.
Pressure Relief: Gradually release pressure, expel water from the tank until the interior is completely emptied.
Inspection and Evaluation: Check for leaks, deformation, or other damage on the surface and interior of the tank. Evaluate the test results to ensure the tank meets design specifications and safety standards.
需要注意的是，液氮储罐水压试验需要由人员进行操作，并遵循相关的安全操作规程。在进行测试前，应仔细阅读和遵守储罐制造商提供的操作指南和安全注意事项。
Our company attaches great importance to technological innovation and R&D design. We have one municipal-level enterprise technology center in Heze City, equipped with non-destructive testing, physical and chemical testing, welding testing, hydrostatic testing, and other testing facilities. We have over 600 types of equipment, including CNC machine tools, X-ray flaw detectors, digital ultrasonic flaw detectors, mechanical property testing machines, chemical analyzers, spectrometers, tensile testing machines, plasma welding machines, and more. The key products we have developed, such as temperature and pressure vessel welding, biomass boiler emission reduction, and waste heat utilization, have successively been included in multiple Shandong Provincial Department of Industry and Information Technology science and technology innovation projects, Shandong key projects, and Heze City innovation and excellence projects. We have accumulated a total of 27 authorized utility models, 16 authorized inventions, participated in drafting 2 standards, 2 industry standards, and registered 15 trademarks. The technical team of our company, in collaboration with Professor Yajiang Li of Shandong University, has jointly developed deep cryogenic container processing technology, which adopts the international plasma arc + wire-filled tungsten inert gas arc welding (PAW-GTAW) technology. After being appraised as a provincial-level scientific and technological achievement, the technology level has reached an international standard in the field of deep cryogenic container manufacturing. Choose Zhongjie Special Equipment, and let's create brilliance together!