Rating is available when the video has been rented.
This feature is not available right now. Please try again later.
Published on Jan 9, 2010
Best effects are at around 2:50. When the bottom air flap is closed, air can enter only through the top hole. If the boiler is sufficiently stuffed with fuel allowing limited gas expansion space, then air is required for combustion. Air goes in through the hole, mixes with the inflammable gases, and expands outwards through the hole preventing air from entering. Combustion collapses allowing air to enter again.