Shandong Zhongjie Special Equipment (formerly Heze Boiler Factory Co., Ltd.) holds an A-grade boiler manufacturing license, A2-grade pressure vessel manufacturing license, A2-grade pressure vessel design license, B-grade boiler installation license, and GB2/Class and GC2/Class pressure pipeline installation licenses, as well as equipment and machinery installation contracting qualifications. It is a member of the China Boiler and Water Treatment Association, the China Chemical Equipment Association, and a director unit of the Shandong Equipment Manufacturing Association. The company has also passed certifications for the ISO9001 Quality Management System, ISO14001 Environmental Management System, OHSAS18001 Occupational Health and Safety Management System, and the U.S. ASME/U2 certification.
Routine inspections and maintenance of liquid oxygen tanks are crucial for ensuring their safe operation. The following are general steps for the daily inspection and maintenance of liquid oxygen tanks:
Visual Inspection: Regularly inspect the exterior of the tank, including the shell, welds, valves, and fittings. Pay attention to any abnormal conditions such as cracks, corrosion, or deformation.
Leak Detection: Utilize suitable leak detection equipment to inspect for leaks in tanks and connection points. Leak detection can be performed using methods such as gas detectors or liquid oxygen detection agents.
Pressure Testing: Regularly conduct pressure tests to check the tank's sealing and pressure resistance. Perform pressure tests in accordance with relevant standards and specifications, and record the test results.
Valve and fitting inspection: Check that the tank's valves and fittings are operating correctly, for any signs of loosening or damage. Ensure the valves open and close smoothly and reliably.
Insulation Layer Inspection: Check for any damage or detachment in the storage tank's insulation layer. Repair or replace any damaged insulation material to ensure effective insulation.
Cleaning and Drainage: Regularly clean the interior of the tank to remove accumulated impurities and dirt. Regularly drain to prevent杂质 and sediments in liquid oxygen from damaging the tank.
Safety Equipment Inspection: Check the safety equipment around the storage tank, such as fire separation zones and alarm systems, to ensure they are functioning properly.
Record and Document Management: Record the results of each inspection and maintenance, including the inspection date, contents, issues found, and measures taken. Establish comprehensive management records and documents to facilitate tracking and managing the storage tank's operation.
Note that inspections and maintenance of liquid oxygen tanks should be conducted by trained personnel and in accordance with relevant regulations and standards. Ensure safety during maintenance and operation, and consult with experts for accurate guidance.

During the welding process of low-temperature liquid storage tanks, controlling the occurrence of welding cracks is crucial. The following are some methods and measures for controlling welding cracks:
Appropriate Welding Processes: Select the appropriate welding process and parameters to minimize heat input and thermal stress. Employ low heat input welding methods such as pulsed welding and laser welding to reduce the temperature gradient and residual stress in the heat-affected zone.
Preheating and Post-Weld Heat Treatment: Perform appropriate preheating before welding to enhance material toughness and reduce thermal stress. Conduct a suitable post-weld heat treatment, such as annealing or stress-relief heat treatment, to minimize residual stress and improve the toughness of the weld.
Select appropriate welding materials: Choose welding materials with good toughness and crack resistance to minimize the occurrence of welding cracks. Select suitable welding materials based on the storage tank's operating conditions and requirements, such as low-alloy steel, stainless steel, etc.
Control Welding Process: Regulate parameters and operations during the welding process to minimize the risk of welding cracks. Pay attention to factors such as welding speed, current, voltage, and welding sequence to avoid overheating or rapid welding, reducing the accumulation of thermal and residual stresses.
Inspection and Evaluation: After welding, conduct non-destructive tests on the welds, such as ultrasonic testing and X-ray testing, to assess welding quality and the presence of cracks. Promptly identify and repair welding cracks to ensure the integrity and safety of the weld joints.
It's important to note that controlling weld cracks is a complex process that requires a comprehensive consideration of factors like material, welding techniques, and operations. When welding low-temperature liquid storage tanks, it's recommended to consult with a welding engineer or a relevant institution for guidance to ensure both the quality of the weld and the safety of the tank.

The reason for occasional venting of liquid oxygen tanks is primarily to maintain the safe pressure range within the tank and prevent excessive pressure buildup. Here are several situations where liquid oxygen tanks may be vented occasionally:
Pressure Control: During operation, the pressure inside a liquid oxygen storage tank can change due to evaporation of the liquid oxygen and temperature variations. To maintain a safe pressure range within the tank, regular venting is required to control the tank pressure within a safe limit.
Prevent Overpressure Accumulation: During the oxygen filling or usage process, due to external factors or operational errors, the pressure inside the liquid oxygen tank may exceed the safe limit. To prevent overpressure accumulation, timely venting is required to alleviate the pressure within the tank.
Prevent Gas Accumulation: Liquid oxygen storage tanks may contain some gas impurities, such as air and water vapor. These gases can condense into liquids or solids at the low temperatures of liquid oxygen, blocking pipes or affecting the normal operation of the tank. Regular venting can expel these impurities, maintaining the tank's cleanliness and unobstructed flow.
Note that the release of liquid oxygen should be performed by a trained operator, adhering strictly to the relevant operational procedures and safety measures. During the release process, care must be taken to prevent leaks and contact with liquid oxygen to ensure operational safety and reliability.

Carbon dioxide and liquid oxygen tanks are containers used for storing different gases; they have some distinct physical properties:
Physical State: Carbon dioxide is a gas at room temperature and pressure, and it needs to be cooled and pressurized to become a liquid. Liquid oxygen is a liquid at room temperature, and it requires cooling to solidify.
Boiling and freezing points: The boiling point of carbon dioxide is -78.5 degrees Celsius, with a freezing point of -56.6 degrees Celsius. The boiling point of liquid oxygen is -183 degrees Celsius, and its freezing point is -218.8 degrees Celsius. The boiling and freezing points of liquid oxygen are significantly lower than those of carbon dioxide.
Density: The density of liquid oxygen is relatively high, at about 1.14 grams per cubic centimeter. Carbon dioxide has a lower density, approximately 0.00198 grams per cubic centimeter. The density of liquid oxygen is about 570 times that of carbon dioxide.
Pressure: Liquid oxygen has a high pressure, typically ranging from tens to hundreds of MPa. Carbon dioxide has a lower pressure, usually within a few MPa range.
Safety: Liquid oxygen has a high oxygen content, which is easily ignited and can cause fires and explosions. Carbon dioxide also poses asphyxiation risks at certain concentrations.
Note that carbon dioxide and liquid oxygen are both highly flammable and explosive substances. Strict adherence to relevant safety operational procedures and standards, along with necessary safety measures, is required for storage and use to ensure the tank's safety and stability.
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