CN

NEWS

2023

Coated sand: installation requirements for safety valves on boilers

Coated sand: The installation requirements for safety valves on boilers should comply with the following requirements: (1) For boilers with a rated evaporation capacity greater than 0.5t/h, at least two safety valves should be installed: for boilers with a rated evaporation capacity less than or equal to 0.5t/h, at least one safety valve should be installed. Safety valves must be installed at the outlet of the separable economizer and the outlet of the steam superheater.

(2) The safety valve should be installed vertically at the highest position of the boiler and header. No outlet pipes or valves for steam extraction shall be installed between the safety valve and the drum or header.

(3) The lever type safety valve should have a device to prevent the heavy hammer from moving on its own and a guide frame to limit the lever from deviating. The spring type safety valve should have a device to lift the handle and prevent the adjustment screw from being easily turned.

(4) For boilers with a rated steam pressure less than or equal to 3.82MPa, the throat diameter of the safety valve should not be less than 25mm; for boilers with a rated steam pressure greater than 3.82MPa, the throat diameter of the safety valve should not be less than 20mm.

(5) The cross-sectional area of the connecting pipe between the safety valve and the boiler should not be less than the inlet cross-sectional area of the safety valve. If several safety valves are installed together on a short pipe directly connected to the drum, the cross-sectional area of the short pipe should not exceed 1.25 times the exhaust area of all safety valves.

(6) Safety valves should generally be equipped with exhaust pipes, which should be directly connected to a safe location and have sufficient cross-sectional area to ensure smooth exhaust. The bottom of the safety valve exhaust pipe should be equipped with a drainage pipe connected to a safe location, and valves are not allowed to be installed on both the exhaust pipe and the drainage pipe.