Safety accessories for pressure vessels
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The safety accessories of pressure vessels include safety valves, rupture disc devices, fusible plugs, emergency shut-off devices, safety interlock devices, etc., which are directly connected to the pressure vessel. The details are as follows: 1. Safety Valves Safety valves consist mainly of a sealing structure (valve seat and valve disc) as well as a loading mechanism (spring or weight, pilot valve). They are special types of valves that are activated by the pressure of the medium on the inlet side to open the valve disc and release pressure, after which they close automatically; they belong to the category of self-closing pressure relief devices. II. Blown disk device: The blown disk device mainly consists of a blown disk (a sensitive element that controls the burst pressure) and a holder (which holds the blown disk in place to ensure sealing as well as stable burst pressure). It is a device that allows for automatic pressure relief by causing the blown disk to rupture under the action of the pressure difference between the inlet and outlet media, and it belongs to the category of non-self-closing pressure relief devices. III. Fuse link: A fuse link utilizes a low-melting-point alloy contained within the device; at higher temperatures, this alloy melts and opens a passage, allowing gas to escape through the holes in the alloy, thereby releasing pressure. Its advantages include a simple structure and easy replacement, and the operating pressure, which is determined by the melting temperature, is relatively easy to control. IV. Emergency shut-off device: The emergency shut-off device generally consists of an emergency shut-off valve, a remote control system, and a fusible plug automatic shut-off mechanism. Its function is to quickly close the valve in case of leaks in the pipelines and their accessories, as well as in the event of misoperations, or in case of a fire near the tank truck, thereby preventing the accident from spreading. V. Safety interlock devices for quick-opening pressure vessels. The safety interlock alarm devices for quick-opening valves are effective measures to prevent operational accidents in quick-opening pressure vessels. Its function is: 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. It has an alarm function that synchronizes with the aforementioned actions.
The person who compiled this material has worked hard by copying so much information, but it could be simplified: 1. Safety valves: These should be calibrated annually, and their setting pressure, discharge diameter, and discharge volume must meet the requirements of technical specifications； 2. Blown fuse devices: They are generally replaced every 2–3 years. Blown fuses used in environments with corrosive or toxic substances, or under harsh conditions, should have a shorter replacement cycle; in such cases, the replacement interval should not exceed one year. The replacement cycle is determined by the user or manufacturer and documented accordingly. The inspection period for blown fuses (with inspection records required) should also not exceed one year. For details, refer to the relevant technical specifications ； 3. Fuse link: The use of a fuse link is similar to that of a burst disc; the temperature of the fuse link selected must meet the design requirements, and it needs to be inspected (inspection records are required). When the amount of refrigerant filled is greater than 2.5 kg, the fuse link cannot be used as the sole release mechanism ； 4. Emergency shut-off device: It is required to undergo type testing to obtain approval from the authorities, just like safety valve discs, but there is no requirement in pressure vessel design to use this device ； 5. Safety interlock device: This equipment requires an R1 operator certificate, and the reliability of the safety interlock device must be checked regularly; the methods and frequency of such checks are specified in the design drawings. An alarm device is not mandatory. For any other detailed requirements, feel free to ask.
VI. Temperature and pressure monitoring instruments for pressure vessels Temperature and pressure monitoring instruments are devices used to monitor the temperature and pressure inside pressure vessels in real time. It can be used to remind operators whether action is needed to keep the pressure vessel within its safe operating range. In addition, there are other auxiliary accessories such as the safety valve drain pipeline system, the exhaust gas discharge pipeline system, and the lubrication system for pressure vessels, all of which are designed to enhance the safety of these vessels. The selection and design of these safety accessories need to be determined based on the specific operating conditions and requirements of the pressure vessel. .
GBT 42595-2023: (