Classification of pressure vessels

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I. Classification by design pressure: 1. Low pressure (L): 0.1 MPa ≤ P < 1.6 MPa; 2. Medium pressure (M): 1.6 MPa ≤ P < 10 MPa; 3. High pressure (H): 10 MPa ≤ P < 100 MPa; 4. Ultra-high pressure (U): P ≥ 100 MPa. II. Classification by function in the process: 1. Reaction pressure vessel (R): Vessels used primarily for carrying out physical and chemical reactions of substances. Such as reactors, reaction kettles, decomposition pots, vulcanization tanks, decomposition towers, polymerization towers, autoclaves, ultra-high pressure vessels, synthesis towers, shift furnaces, cooking pots, steam balls, autoclaves for autoclaving, gas generators, etc. 2. Heat exchange pressure vessel (E): It is primarily a pressure vessel used to facilitate heat exchange of fluids. Such as shell-and-tube waste heat boilers, heat exchangers, coolers, condensers, evaporators, heaters, sterilization kettles, dyeing machines, drying cylinders, steaming and frying kettles, preheating kettles, solvent preheaters, steam boilers, steam stripping machines, electric steam generators, gas generator water jackets, etc. 3. Separation pressure vessel (S): Mainly used for achieving fluid pressure balance and buffering, as well as gas purification and separation. Such as separators, filters, oil collectors, buffers, washers, absorption towers, copper washing towers, drying towers, stripping towers, steam distributors, deaerators, etc. 4. Storage pressure vessels (C, with spherical tanks denoted as B): These are pressure vessels primarily used for storing gases, liquids, liquefied gases, and other such substances, such as various types of storage tanks. III. Comprehensive Classification 1. Fixed-pressure vessels: Used in a fixed environment and cannot be moved. There are a wide variety of working media, most of which are various chemical hazards that are toxic, flammable, explosive, and corrosive. Such as spherical storage tanks, horizontal storage tanks, various heat exchangers, synthesis towers, reactors, dryers, separators, shell-and-tube waste heat boilers, and manned containers (such as medical oxygen chambers), etc. 2. Mobile pressure vessels: They are primarily used while in motion, serving as containers for certain media and mounted on vehicles for transportation. Many working media are flammable, explosive, or toxic. Such as the tanks of cars and railway tank cars. 3. Gas cylinder-type pressure vessels: As a type of pressure vessel, they are widely used in society; there are high-pressure gas cylinders (such as those for hydrogen, oxygen, and nitrogen) and low-pressure gas cylinders (such as those for household liquefied petroleum gas). The working media in these cylinders are often flammable, explosive, or toxic substances. It also has high mobility, featuring both long-distance movement during transportation and short-distance movement in actual use. Such as liquefied petroleum gas cylinders, oxygen cylinders, hydrogen cylinders, nitrogen cylinders, carbon dioxide cylinders, liquid chlorine cylinders, liquid ammonia cylinders, and dissolved acetylene cylinders, etc. III. Safety accessories for pressure vessels 1. Safety valves: The function of safety valves is to open automatically when the pressure inside the equipment exceeds the specified limit, thereby releasing the excess pressure and allowing the equipment to return to its normal operating pressure level. Once the pressure returns to normal, the safety valve closes automatically. After the safety valve has been calibrated, it is strictly prohibited to increase its set pressure or render it ineffective by means such as adding weights, moving the weight, or locking the valve disc in place. 2. Pressure gauge: The range of the pressure gauge should be appropriate to the operating pressure of the equipment; it is usually 1.5 to 3 times the operating pressure, with 2 times being the ideal value. A red line should be marked on the pressure gauge dial to indicate the maximum allowable operating pressure. The connection tubes of the pressure gauge should not leak water or steam, as this will lower the reading indicated by the gauge. 3. Blown fuse 4. Thermometer 5. Level gauge 6. Pressure relief valve 7. Emergency shut-off device: Its function is to quickly close the valve in case of a rupture in the pipeline and its accessories, as well as due to improper operation, or in the event of a fire near the tank truck, thereby preventing the accident from spreading. 8. Safety interlock device for quick-opening pressure vessels: The safety interlock alarm device for quick-opening doors is an effective measure to prevent operational accidents in quick-opening pressure vessels. Its functions are: a. An interlock control function that allows the pressure to increase only when the fast-opening door reaches the predetermined closed position ； b. The interlock function for opening the quick-opening door can be activated only after the internal pressure of the pressure vessel has been completely released and the safety interlock device has been disengaged ； c. Possesses an alarm function that synchronizes with the aforementioned actions