Pressure Relief Device for Explosive Pipelines or Equipment Explosion-proof Valve The explosion-proof valve is used in dust removal systems containing flammable gases or combustible materials and can serve as a pressure relief device for explosive pipelines or equipment. The diaphragm of the explosion-proof valve is typically calculated based on the operating pressure of the dust removal system and the concentration of combustible substances, after which the material and thickness are selected. It is crucial to avoid improper selection that could affect the normal operation of the system.[1] There are generally two types of explosion-proof valves: horizontal and vertical. Both types adopt a structure with an explosion-proof diaphragm covered by a cap. The vertical explosion-proof valve is installed on the cylinder body, while the horizontal one is mounted on the top. Explosion-proof valves are primarily used in hydraulic systems of large-scale mechanical stages, lifters, elevators, automotive inspection and repair frames, and other equipment without mechanical locking systems. They mainly provide protection against safety accidents and serve as a locking measure for hydraulic systems. This requirement is mandatory in CE certification, so explosion-proof valves were first invented and produced in Europe. Later, they spread to China and have since been widely adopted. The explosion-proof valve has a simple structure and a compact, small size, making it easy to connect to the inlet of the actuator unit. Working Principle The working principle of the explosion-proof valve: The solenoid valve contains a sealed cavity with through-holes at different positions, each hole leading to a different oil pipe. In the middle of the cavity is a valve, with two electromagnets on either side. When the coil of the magnet on one side is energized, the valve body is attracted to that side, thereby controlling the movement of the valve body to block or allow the flow through different oil discharge holes. The oil inlet port is normally open, allowing hydraulic oil to enter different oil discharge pipes. Then, the oil pressure pushes the piston, which in turn drives the piston rod, and the piston rod moves the mechanical device. Thus, by controlling the current flowing through the electromagnets, mechanical motion is controlled. Operating Conditions 1. Pressure range: -10 kPa ~ +20 kPa 2. Temperature range: -20℃ ~ 395℃ Installation Location On the boiler body and the flue duct before the dust collector, where internal explosions are likely to occur. Installation Requirements 1. The explosion-proof valve can be installed at any angle. 2. The minimum spacing between two explosion-proof valves is 200 mm. Structure The explosion-proof valve has a simple structure, consisting of a steel welded cylinder body and an explosion-proof diaphragm. When the system pressure exceeds 0.1 MPa or the set pressure, the explosion-proof diaphragm ruptures automatically, preventing the system from exploding and ensuring production and personal safety. This valve comes in two types: circular (Type I) and square (Type II).[1] Main Dimensions of Explosion-Proof Valves (mm) A×A B×B C×C H n×d Mass/kg DN D D1 H n×d Mass/kg 200×200 270×270 305×305 220 8×φ18 40 200 305 270 220 9×φ18 37 250×250 335×335 370×370 250 12×φ18 48 250 370 335 250 12×φ18 44 300×300 385×385 425×425 300 12×φ18 54 300 425 385 300 12×φ18 55 350×350 435×435 477×477 350 12×φ18 67 350 477 435 350 12×φ18 65 400×400 490×490 536×536 400 12×φ18 85 400 536 490 400 12×φ18 82 450×450 540×540 588×588 450 16×φ18 99 450 588 540 450 16×φ18 94 500×500 600×600 649×649 500 16×φ18 112 500 649 600 500 16×φ18 108 600×600 700×700 750×750 550 16×φ18 152 600 750 700 550 16×φ18 142 700×700 800×800 850×850 550 16×φ22 204 700 850 800 550 16×φ22 180 800×800 900×900 950×950 600 20×φ22 228 800 950 900 600 20×φ22 202