Knowledge on the use of pressure vessels

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I. Inspection Standards for Pressure Vessels The basis for conducting inspections on imported and exported pressure vessels is the Inspection Law and the Measures for the Supervision and Management of Imported and Exported Boilers and Pressure Vessels. 　　The inspection of pressure vessels is carried out in accordance with **relevant regulations and technical standards; it involves a comprehensive evaluation of the rationality of the vessel’s structure, the strength of its pressure-bearing components, the quality of its manufacturing and installation, any internal or external defects, as well as the accuracy and reliability of its safety accessories, in order to draw definitive conclusions. 　　There are many standards involved in the inspection of import and export pressure vessels. Generally speaking, they include the following: 1. Regulatory provisions: Such inspection standards are **issued by authorities and are mandatory; they represent the rules, regulations, or specifications that must be followed in the design, manufacturing, installation, operation, and management of pressure vessels. 　　Such regulatory provisions serve as an important basis for the inspection of pressure vessels. In our country, there are regulations such as the Interim Regulations on the Safety Supervision of Boilers and Pressure Vessels, the Procedures for the Safety Supervision of Pressure Vessels, the Design Specifications for Steel Pressure Vessels Used in the Petroleum and Chemical Industries, as well as the Rules for the Examination of Welders Working on Boilers and Pressure Vessels, and the Rules for Assessing the Qualifications of Personnel Engaged in Non-Destructive Testing of Boilers and Pressure Vessels. 　　Whether it is an imported or exported container, if any aspect does not comply with such regulations, that pressure vessel cannot be used. 2. Specific technical regulations: There are numerous technical standards related to the inspection of pressure vessels. Such standards include: material standards, material testing standards, material acceptance standards, component standards, product standards, process standards, and process quality inspection standards, etc. Roughly speaking, there are over 20 in our country. These standards are specific technical documents that define a series of technical parameters and criteria for product quality characteristics; they serve as a measure for assessing product quality. 　　In our country, such standards include national standards (GB), industry standards (JBYB), and enterprise standards. 3. Standards specified in the contract: Given the special nature of pressure vessels, China’s regulations stipulate that the quality of imported and exported pressure vessels, particularly their safety performance, must not be lower than the requirements of China’s current standards. Therefore, when conducting technical negotiations and signing the contract, both parties should pay attention to any elements that fall below China’s standards, in order to avoid situations where the product cannot be used due to non-compliance with these standards. II. Pressure testing items and testing methods 1. Testing scope: The inspection of imported and exported pressure vessels covers the following areas: review of the design of pressure vessels, inspection of the operational quality of pressure vessels, inspection of the installation quality of pressure vessels, inspection of the quality of repairs to pressure vessels, and inspection of their operational quality. In short, any factor that can affect the safe operation of pressure vessels falls within the scope of inspection. 2. Inspection items and methods: The inspection of imported and exported pressure vessels generally includes two main aspects. That is, review of design documents and physical inspection. Depending on the inspection requirements, for exports, personnel can be sent to the factory for inspection and supervision; for imports, personnel are dispatched abroad to oversee manufacturing or conduct inspections. 　　(1) Review of design documents: The review of design and manufacturing documents involves not only checking whether the documents are complete but also ensuring that they meet the required standards. 　　The document review includes the following: whether the equipment drawings, quality certificates, product approval documents, etc. are complete and meet the required standards. This should include material certificates and strength calculations for the main stressed components, welding certification, welding procedures, heat treatment procedures, pressure testing reports, and other documents related to the inspection of safety performance. 　　Review of structural rationality. These include the design and calculation documents for the safety accessories. 　　(2) Physical inspection: Methods such as visual inspection, dimensional inspection, non-destructive testing, physical and chemical property testing, and hydrostatic testing are employed to examine the appearance and internal quality of the pressure vessel itself and its main components. 　　The main inspection items include: the material of the pressure-bearing components, their external dimensions and shaping quality, weld quality, assembly quality, whether the internal devices and safety accessories are complete and functional, expansion tube quality, the geometric alignment of the various pressure-bearing components, and their pressure resistance. 　　(3) Performance: Pressure vessels that have passed the technical documentation review and physical inspection may undergo performance testing as necessary, to verify their specified technical and economic parameters. 　　In addition to the above inspection items, for imported and exported pressure vessels, inspections of the overall appearance, quantity, packaging, etc. are also required in accordance with relevant standards. III. Others 　　At present, the specific types of import and export pressure vessels that are classified as \"commodities subject to mandatory inspection\" under inspection and quarantine include various storage and transportation vessels, reaction vessels, heat exchange vessels, and separation vessels with a working pressure of >0.1 Mpa; in total, there are 58 types across four categories. In addition, there are separate regulations for defective vehicles and gas cylinders; the situation regarding these two types of goods will be discussed separately. 　　In addition to being imported and exported separately, pressure vessels often appear in import and export trade as part of complete sets of equipment. Therefore, during contract signing and technical negotiations, clear requirements should be set regarding the technical documentation, inspection standards, and inspection methods for pressure vessels in accordance with relevant national regulations, to ensure the quality of the goods and the smooth progress of the inspection process.