What is Reasonable Boiler Flue Design


The flue is the main way for the gas boiler to discharg […]

The flue is the main way for the gas boiler to discharge the flue gas. If the design is unreasonable, it is easy to make the flue gas generated during the operation of the boiler unable to be discharged outside the boiler normally, causing damage to the gas boiler. So, what are the design requirements for the flue of a gas boiler?

1. The flue should be designed as straight as possible, so that the airtightness of the flue will be good, with fewer attachments and less resistance. When laying a horizontal flue, it should be arranged with an elevation of more than 1%, and try to avoid laying along the slope.

2. The flue and chimney of the fuel gas boiler room should be constructed of steel or reinforced concrete, and the lowest point of the flue and chimney should be equipped with a water-sealed air-conditioning water drainage pipe.

3. The steel plate thickness of the metal flue is generally 4~6mm. When designing the flue, sufficient reinforcing ribs should be configured to ensure the strength and rigidity requirements.

4. The thermal expansion of the flue should be compensated, and the compensation amount should be calculated and correctly selected.

5. The steel flue should have insulation measures and reliable fixation.

6. One boiler should correspond to one chimney in the fuel-fired gas boiler room. When several boilers need to share one flue or chimney due to conditional constraints, the ventilation and draft force of each boiler should be balanced.

7. When laying out the flue, necessary thermal and environmental measuring points should be set at appropriate positions.

8. In places where smoke is easy to gather and when multiple boilers share a chimney or a common flue, an explosion-proof door should be installed on the flue behind each fuel-fired gas-fired boiler. The position of the explosion-proof door should be conducive to pressure relief. It should be installed at an appropriate position that does not endanger the safety of personnel and before turning. When the explosion gas may endanger the safety of operators, a pressure relief guide pipe should be installed on the explosion-proof device.

9. For some boiler rooms with long flue, the resistance should be calculated, and the corresponding blower and induced draft fan (when there is an induced draft fan) should be selected to ensure the smooth exhaust of smoke.

10. Corresponding anti-corrosion measures should be considered for the chimney. The flue gas temperature at the chimney outlet should be 15°C higher than the flue gas dew point temperature; when the exhaust gas temperature is lower than the flue gas dew point temperature, effective measures should be taken to prevent the flue gas from flowing backward.

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