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Proper use of explosion-proof sealant during the installation of instrumentation electrical equipment. Sealant is often used for isolation and sealing during the installation of explosion-proof electrical equipment; it is sometimes referred to as “explosion-proof sealant,” but it should actually be called “sealant for explosion-proof equipment.” 1. Application scope of explosion-proof putty: Explosion-proof putty is used in fields such as national defense, petroleum, chemicals, gas stations, substations, power plants, industrial and mining enterprises, high-rise buildings, shipbuilding and power industries, postal and telecommunications services, metallurgy, hazardous warehouses, and other locations where there is a risk of explosions. It serves as an explosion-proof isolation seal for wire ducts or cable wiring systems. Used to seal holes in wires and cables, preventing fires in these wires and cables from spreading to adjacent rooms through the holes and thus reducing fire damage. It prevents the expansion of accidents and has functions such as smoke suppression, fire prevention, and dust control. 2. Characteristics of explosion-proof putty: ① It possesses good flexibility, resistance to aging; it does not flow at high temperatures nor crack at low temperatures. ② It provides good adhesion to metals, cable coatings, etc., and offers excellent airtightness as well as non-explosive properties. ③ It is tasteless, non-toxic, and non-corrosive, making it easy to apply and maintain. ④ Using explosion-proof sealed isolation pipe fittings in combination enhances the explosion-proof effect. 3. When is an explosion-proof isolation seal needed? The chemical production process involves flammable and explosive hazardous materials, and preventing leaks as well as fire and explosion accidents caused by such leaks is an important aspect of safety management. This is typically achieved by dividing the explosion-proof areas, selecting electrical equipment with the appropriate explosion-proof rating, and controlling hot work within those areas. Electrical circuits in areas prone to explosions must be equipped with explosion-proof isolation seals, the purpose of which is to prevent explosive gases or flames from spreading through the pipes to other parts. Explosion-proof putty consists of two components, A and B. Under normal conditions, as shown in the figure above, these two components should be water-impermeable, non-shrinking, and free of cracks after curing; therefore, it is widely used in petrochemical facilities. The use of explosion-proof putty in flameproof electrical equipment typically occurs in the following three situations: ① Inside the stuffing tube of flameproof stuffing box-type insertion devices. ② Inside the isolation seal box. ③ At the wiring point between the flameproof chamber and the enhanced safety chamber/flameproof chamber. When explosion-proof putty is used in flameproof electrical equipment, it generally serves as part of the flameproof enclosure. It is important to ensure that the minimum sealing length is at least 20 mm, and that at every point along the axial length of the seal, at least 20% of the cross-sectional area is effectively filled by the sealing putty. The spacing between wires must also meet the standard requirements. The sealing mortar must also pass pressure resistance tests on the enclosure, non-propagation tests in the event of internal ignition, as well as heat and cold resistance tests conducted by third-party testing institutions. Furthermore, it should be noted that explosion-proof putty cannot be used for sealing the redundant inlet of explosion-proof equipment. 4. Incorrect application scenarios for explosion-proof putty: Using explosion-proof putty as a method for explosion-proof sealing is not effective and introduces additional risks. In the explosion-proof design of electrical equipment, explosion protection is divided into various types, such as intrinsically safe type, increased safety type, flameproof type, positive pressure type, sand-flushing type, type N, and so on. The flameproof structure achieves its explosion-proof function through its flameproof enclosure, whose role is to: ① withstand the explosion of flammable gas mixtures generated by the internal electrical components without being damaged. ② The high-temperature gases generated by the internal explosion, as they are released outward along the sealed joints of the casing, can cause the gas temperature to drop to a level that prevents further explosions in any flammable gas mixtures present in the external environment. Explosion-proof equipment needs to provide explosion protection, and both mechanical strength and an adequate gap length at the joints are essential. Explosion-proof putty cannot perform the above two functions when used for sealing (unless the equipment manufacturer has incorporated a structural design such as an annular groove or internal threaded retention mechanism). In the event of an accident, an explosion inside electrical equipment could blow out the explosion-proof putty, thereby failing to achieve the purpose of explosion protection. Furthermore, covering with explosion-proof putty prevents the effectiveness of the equipment’s original explosion-proof sealing surfaces from being verified through routine inspections, thereby introducing greater risks.