why negative pressure is maintained in furnace?

Depending are two types of boiler depending on pressure:-
  1. Positive pressure :- When the pressure in combustion area of the boiler is more than atmospheric pressure, normally forced draft boilers, HRSG are positive pressure.
  2. Negative pressure :-When the pressure in combustion area of the boiler is less than atmospheric pressure. This is achieved in balanced draft boilers by using Forced draft fans to force air into boiler (pressuring it)and Induced draft fans to remove air from the boilers to create negative pressure.
In general negative pressure boilers are preferred as any flames or exhaust from boiler don't have a tendency to spread outside as the pressure inside is lower. The air ingresses inside incase of small leaks between boiler tube fins( large boiler are not perfectly sealed and have small gaps between fins) and contains the flames in the boiler. It also reduces the risk of explosions in boilers w.r.t. positive pressure boilers.

Comments

  1. Unknown29 November 2018 at 23:04

    Pàààpq

    ReplyDelete
  2. Victoria Martinez21 February 2019 at 05:19

    These hints of furnace malfunction are pretty helpful. Furnace needs regular maintenance as its working 24/7. High Efficiency Furnace

    ReplyDelete
  3. Hazel Grace10 February 2020 at 15:06

    The flue gas system consists of two air heaters. The combustion gas transfers its own heat to the water wall, the superheaters, the reheater and the economizer, then leaves the boiler to the flue gas ducts.

    boiler heating treatment company in Ontario

    ReplyDelete
  4. Unknown25 September 2021 at 07:36

    Sir at our plant draft is crossing —30 or above, with low suction by id fan(low current) what is reason behind this? I can't understand. Current are maintained at 40A and damper position are less than 25%. Could you please explain.

    ReplyDelete

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