Boiler safety valve installation need to pay attention to what
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October 12 02:00:15, 2025
Safety valves must be installed according to specific guidelines to ensure the safe operation of steam boilers. First, any steam boiler with a rated evaporation exceeding 0.5 tons per hour must have at least two safety valves. For boilers with a rated evaporation of 0.5 tons per hour or less, a single safety valve is sufficient. Additionally, safety valves are required on the outlet of separable economizers and steam superheaters to prevent overpressure in these components.
Second, each safety valve should be mounted vertically at the highest point of the boiler drum and header. It's crucial that no additional piping or valves are installed between the safety valve and the drum or header, as this could interfere with the proper release of steam during an overpressure situation.
Third, for lever-type safety valves, there must be mechanisms in place to prevent the hammer from moving unintentionally and to guide the lever so it doesn't derail. Spring-type safety valves should include a lifting handle and a locking mechanism to prevent the adjustment screw from being turned easily, ensuring the valve remains set at the correct pressure.
Fourth, the throat diameter of the safety valve depends on the boiler's rated steam pressure. If the pressure is 3.82 MPa or lower, the throat diameter must be at least 25 mm. For higher-pressure boilers, the minimum throat diameter is 20 mm to ensure adequate steam flow during relief.
Fifth, the connecting pipe between the safety valve and the boiler must have a cross-sectional area equal to or greater than the inlet area of the valve. When multiple safety valves are installed on a short pipe connected directly to the drum, the short pipe's cross-sectional area must be at least 1.25 times the total exhaust area of all the safety valves combined.
Finally, each safety valve should be equipped with an exhaust pipe that leads to a safe location. The exhaust pipe must have enough cross-sectional area to allow unobstructed steam discharge. At the bottom of the exhaust pipe, a drain line should be installed, leading to a safe area. Importantly, no valves should be placed on either the exhaust or drain pipes to avoid blocking the release of steam during emergencies.