Key points of knowledge on pressure vessels

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Pressure vessels are exposed to high levels of pressure, temperature, and other parameters during operation; should any safety issues arise, the consequences can be extremely severe. Therefore, the safety of pressure vessels has always been a focus of attention in various industries. This article will summarize the key safety aspects of pressure vessels from aspects such as design, manufacturing, inspection, and use, for reference. 1. Design phase: When designing pressure vessels, parameters such as pressure, volume, and material should be selected appropriately based on factors such as the operating environment, properties of the medium, and requirements of the processing equipment. Safety considerations must also be fully taken into account during the vessel design process. For example, when determining the design pressure, an appropriate pressure range should be established based on factors such as the strength of the container material and the operating conditions, in order to avoid accidents such as explosions caused by overpressure ； When designing the volume, factors such as changes in the volume of the medium and the tensile deformation of the container material must be fully considered to prevent safety issues such as container rupture caused by changes in its volume. 2. Manufacturing stage: When manufacturing pressure vessels, professional manufacturing equipment and advanced processes should be used in accordance with regulatory requirements, to ensure that the quality of the vessels meets **standards and customer specifications. To ensure the safety of containers, the following key points should be focused on during the manufacturing process: first, control the quality of the materials to avoid issues such as material defects and cracks ； Second, strengthen welding quality control to prevent container rupture caused by poor weld quality or cracks ； Third, conduct strict pressure tests to ensure that the container can withstand the rated pressure and temperature under normal conditions. 3. Operation phase: During the use of pressure vessels, it is necessary to strictly adhere to the design, manufacturing, and operating procedures to ensure their safe operation. The following points must be strictly followed: First, the containers should be regularly inspected and maintained to prevent safety hazards such as corrosion and fatigue inside them ； Second, monitor the pressure and temperature parameters of the container to prevent accidents caused by overpressure or overheating ； Third is standardized operation; it is prohibited to handle containers in an improper manner to prevent safety accidents caused by operational errors. 4. Inspection phase: In the inspection of pressure vessels, visual inspections, material tests, pressure tests, and other procedures must be carried out regularly or as needed, in accordance with relevant regulations, in order to identify and address any potential safety hazards present in the vessels promptly. It is recommended to conduct regular and planned ultrasonic testing and magnetic particle testing on large pressure vessels, in order to prevent accidents caused by defects such as microcracks. 5. Emergency response: In the event of an accident involving a pressure vessel, emergency measures should be taken promptly in accordance with the emergency response plan to prevent the accident from escalating. Relevant personnel should be notified promptly to stop using the associated equipment, measures should be taken to eliminate the threat, the accident scene should be dealt with, and the relevant authorities should be informed. Colleagues, companies should also keep records of accidents and incidents, and implement corresponding safety improvement measures. Summary: The above is an overview of the key points regarding the safety of pressure vessels. To ensure their safety, it is necessary to follow relevant regulations strictly at all stages, including design, manufacturing, use, inspection, and emergency handling, as well as to strengthen management and implement comprehensive control measures. For example: Conduct regular inspections of the equipment to ensure there are no cracks or damages, and that it can operate properly under specified pressures. This is an effective way to ensure the safe operation of pressure vessels. Some common issues in the drawing of pressure vessel diagrams 1. Part sequence in the detail list (1) The drawings of the components and the parts that belong to them should, as much as possible, be drawn on the same sheet or on adjacent sheets numbered consecutively, with the component drawings placed at the right side or lower right side of the sheet. (2) When several different components need to be arranged across multiple drawings, it is advisable to first place the important or more complex components along with their related parts, or to arrange them in order of part numbers. (3) Relevant components that are closely related in terms of processing, installation, and structure should be arranged on the same drawing as much as possible. 2. Interrelationships between drawings: When a device is highly complex and a single assembly drawing cannot accommodate all the projections, views, tables, and technical specifications, it is permissible to create two or more assembly drawings. However, the following principles must be followed: (1) The front view, technical specifications, table of technical characteristics, list of pipe connections, detail columns, and annotations should be included on the first drawing. (2) Top views, side views, front views, enlarged views, cross-sections, etc. should be placed on the 2nd or 3rd drawing. (3) On each drawing, the relationship between this drawing and other drawings should be indicated. For example, on the front view drawing, it should be noted that the top view and the view from direction A are on drawing xxx-2 (i.e., the second drawing). Indicate on the top-view drawing that the front view and technical requirements are listed on drawing xxx-1 (i.e., on the first drawing). 3. Draw part drawings on the assembly drawing. Generally, part drawings should not be included within the area of the assembly drawing. Since the parts need to go through several processing steps, placing them on the assembly drawing sheet makes it impossible to separate them, which is very inconvenient. Paragraph 4.5.1 of HG/T 20668-2000 \"Specifications for the Preparation of Design Documents for Chemical Equipment\" stipulates that \"...for simple equipment that consists of only a few components, it is allowed to place the components and the assembly drawing on the same sheet; in such cases, the sheet size should not exceed size No. 1, with the assembly drawing placed on the right side of the sheet.\" That is, the part drawings can be separated from the assembly drawings and used independently. 4. Inconsistent names: For example, a certain angle steel ring is referred to as angle steel in the details column, as a support ring in the technical requirements or specifications, and as a reinforcement ring in the component title column. Another example: a certain type of reinforcement plate may have various names in different detail lists or technical specifications and descriptions, such as steel plate, reinforcement plate, support plate, strengthening plate, connection plate, etc. The correct designation is such that any part or component has only one identical and uniform name in all the details or textual descriptions within a set of drawings. 5. Repeated symbols: It is incorrect to use the same symbol (or code) to represent different meanings or different shapes on the same drawing. For example, using A-A for both expansion and cross-section views is incorrect. To avoid confusion and misunderstandings, the proper notation should be used as follows: A-A cross-section, B-B view from another direction, C-C rotated view, D-D expanded view; A as the reference point, B as the view from another direction. If different parts of a single component use the same cutting symbol to indicate the same type of view (such as multiple identical keyways on the same diameter shaft), then the same cutting symbol can be used repeatedly on the same drawing. 6. No specific scale indicated: All views in the drawing, as well as the dimensions of parts and components within those views, shall be drawn at the same scale each. This is especially true for the assembly areas of the main components as well as other critical parts. If not drawn in proportion, it can easily lead to illusions or distortions in the pattern, and may even result in structural errors that go unnoticed. When not in proportion, the words “not in proportion” should be indicated. When individual dimensions are not to scale, it is recommended to draw a thin solid line below the dimension numbers.