Boiler safety valve valve common fault analysis of coal steam boiler safety valve requirements
Summary: analyzed the boiler safety valve valve leakage, body surface leakage, impulse safety valve action after the relief valve is not action, impulse safety valve seat left in the relief valve delay back to the seat back a long time and low back pressure of safety valve, frequency jump and flutter and other common fault causes, and put forward the solution for the cause of the problem.
1. Requirements for safety valve of coal-fired steam boiler steam boiler evaporation capacity is greater than 0.5t/h, at least 2 safety valves are installed, rated evaporation capacity is less than or equal to 0.5t/h, at least 1 safety valve. When the rated thermal power of the hot water boiler is greater than 1.4MW, at least 2 safety valves shall be installed; When the rated heat supply is less than or equal to 1.4MW, at least 1 safety valve shall be installed.
Separable economizer outlet, steam superheater outlet, must be equipped with a safety valve. The boiler with rated steam pressure less than 0.1mpa can use static weight safety valve or water seal type safety device.
The safety valve should be installed straight, and should be installed in the drum, the highest position of the collection box. Between the safety valve and the drum or between the safety valve and the collection box, there shall be no outlet pipe and valve for steam. The TOTAL exhaust steam OF the safety valve must be greater than the rated evaporation of the boiler, and after all the safety valves on the drum and superheater are opened, the steam pressure in the drum shall not exceed 1.1 times the design pressure. The exhaust volume of the superheater safety valve should ensure that the superheater gets enough cooling under the exhaust volume and will not be burned out.
Vertical steam boiler safety valve must have the following device: spring type safety valve should have a lifting handle and prevent the adjustment screw device. The lever type safety valve should have a device to prevent the weight from moving by itself and a guide frame to limit the lever from going out. The static weight relief valve shall have a device to prevent the weight from flying off.
For boilers with rated steam pressure less than or equal to 3.82Mpa, the safety throat diameter shall not be less than 25mm; For boilers with rated steam pressure greater than 3.82Mpa, the throat diameter of the relief valve shall not be less than 20mm. Several safety valves are installed on a short pipe directly connected with the drum, and the cross-sectional area of the short pipe should not be less than the sum of the area of the exhaust pipe of all safety valves.
The safety valve should generally be equipped with exhaust pipe, exhaust pipe should be directly outdoor as far as possible, and have enough cross-sectional area, to ensure the smooth exhaust steam. The bottom of the relief valve exhaust line shall be equipped with a water line to a safe location. Valves shall not be installed in the exhaust pipe or in the supply pipe. The SAFETY VALVE ON THE ECONOMIZER SHALL BE FITTED WITH a DRAIN PIPE AND RUN TO a SAFE LOCATION. No VALVES SHALL BE INSTALLED ON THE DRAIN PIPE.
Post time: Sep-29-2022