The function of blast discs, their installation methods, and the situations in which they are installed

A burst disc is an uncloseable pressure relief device that opens at a predetermined pressure; it is generally used in conjunction with safety valves and is connected using flanges. There are two types: arched and flat.

Article 160 and subsequent articles of the \"Regulations on the Safety Supervision of Pressure Vessels\" contain explanations regarding this matter!

Article 140: The safety valves, rupture disc devices, emergency shut-off devices, pressure gauges, level gauges, temperature measuring instruments used in pressure vessels, as well as the safety interlock devices for quick-opening pressure vessels, shall comply with the provisions of these regulations. The unit that manufactures rupture disc devices must hold a manufacturing license issued by the **Quality and Technical Supervision Bureau. Units that manufacture safety valves, emergency shut-off devices, level gauges, and safety interlock devices for quick-opening pressure vessels must be approved by a safety supervision agency at or above the provincial level (including provincial levels). Article 141: Pressure vessels in use within the scope of application of these regulations shall be equipped with safety relief devices (safety valves or rupture discs) in accordance with the design requirements. When the pressure source is external to the pressure vessel and can be reliably controlled, a safety relief device does not need to be installed directly on the pressure vessel. Article 142: When a safety valve cannot operate reliably, a burst disc device shall be installed, or a structure combining a burst disc device and a safety valve device shall be employed. When a composite structure is used, the relevant provisions of Appendix B of GB150 shall be complied with. Any burst disc connected in a composite structure must not generate fragments when it activates. Article 143: The design and manufacture of safety accessories shall comply with the corresponding **standards and industry standards. Article 144: For pressure vessels containing flammable media or media with an extremely high, high, or moderate level of toxicity, pipes shall be installed at the discharge outlets of safety valves or rupture disks to direct the discharged media to a safe location where they can be properly disposed of; such media shall not be released directly into the atmosphere. Article 145: The discharge capacity of safety valves and rupture discs must be greater than or equal to the safe discharge capacity of the pressure vessel. The calculation of discharge capacity and safe venting volume is provided in Appendix 5. For pressure vessels filled with a gas-liquid mixture in a saturated or superheated state, the discharge diameter must be calculated when designing the rupture disc device to prevent a spatial explosion. Article 146: When only one safety valve is installed on a fixed-pressure vessel, the opening pressure Pz of that safety valve shall not be greater than the design pressure P of the vessel, and the sealing test pressure Pt of the safety valve shall be greater than the highest operating pressure Pw of the vessel; that is, Pz ≤ P and Pt > Pw. When multiple safety valves are installed on a fixed-pressure vessel, the opening pressure of one of those safety valves shall not be greater than the design pressure of the vessel, while the opening pressures of the remaining safety valves may be increased appropriately, but must not exceed 1.05 times the design pressure. Article 147: The opening pressure of the safety valve on mobile pressure vessels shall be 1.05 to 1.10 times the design pressure of the vessel; the rated discharge pressure of the safety valve shall not exceed 1.2 times the design pressure of the vessel, and the reset pressure shall not be less than 0.8 times the opening pressure. Article 148: When a rupture disc device is installed on a fixed-pressure vessel, the designed burst pressure PB of the rupture disc shall not be greater than the designed pressure of the vessel, and the minimum designed burst pressure of the rupture disc shall not be less than 1.05 times the highest operating pressure PW of the vessel; that is: PB ≤ P, and PBmin ≥ 1.05Pw

Function of the blast disc: 1. It can isolate corrosive media, reduce the requirements for the material of safety valves, and thus save a significant amount in investment costs ； 2. It can isolate media that are prone to clogging, ensuring the proper operation of the safety valve ； 3. Both of the above take into account the need for the element to return to its original position after pressure release in order to maintain system pressure; if this is not necessary, a burst disc can be used directly ； 4. Furthermore, on occasion, consideration is given to indirectly providing the maximum operating pressure of the equipment. This is because the leakage rate of ordinary safety valves is around 85% to 90%, whereas rupture disks can achieve a setting of around 95% at a lower cost.

\"Specifications for the Engineering Design of Process Systems in Chemical Plants\" HG/T20570.3-95 4 Installation of blast discs 4.0.2 Blast discs should be given priority when one of the following conditions applies: 4.0.2.1 The pressure is likely to rise rapidly； 4.0.2.2 The discharge medium contains particles, is prone to precipitation, crystallization, and polymerization, and has a high viscosity ； 4.0.2.3 The medium released is highly corrosive; safety valves used for it are very expensive ； 4.0.2.4 When the process medium is extremely valuable or highly toxic, any leakage during operation is not allowed; it should be used in series with a safety valve ； 4.0.2.5 When the operating pressure is very high or very low, it is difficult to manufacture safety valves in such cases ； 4.0.2.6 When lower operating temperatures affect the performance characteristics of the safety valve ； 4.0.2.7 Requires a large area.

\"Specifications for the Engineering Design of Process Systems in Chemical Plants\" HG/T20570.3-95 4 Installation of blast discs 4.0.2 Blast discs should be given priority when one of the following conditions applies: 4.0.2.1 The pressure is likely to rise rapidly； 4.0.2.2 The discharge medium contains particles, is prone to precipitation, crystallization, and polymerization, and has a high viscosity ； 4.0.2.3 The medium released is highly corrosive; safety valves used for it are very expensive ； 4.0.2.4 When the process medium is extremely valuable or highly toxic, any leakage during operation is not allowed; it should be used in series with a safety valve ； 4.0.2.5 When the operating pressure is very high or very low, it is difficult to manufacture safety valves in such cases ； 4.0.2.6 When lower operating temperatures affect the performance characteristics of the safety valve ； 4.0.2.7 Requires a large area. It’s the same content as above; our training the day before yesterday was also based on this material.

Types and functions of rupture disc applications, as well as installation conditions

Connection method: bolt connection, clamp connection, flange clamping connection