Thanks Keith, With experts like you and J.R wot else can a fellow need.
I'll write you off list as you kindly offer. Geoff >Geoff, >While opening the fire door a bit, does have it's uses, it will also >give some extra oxygen to burn up the unburned coal in the smoke, and >give you a bit cleaner stack, at such times, like when you first put on >a big batch of green coal. But, you still need to control the air UNDER >the fire, to get better control of the fire!! The air coming in on TOP >of the fire, will only react with the unburned carbon in the smoke, and >will not greatly affect the fire bed. which gets it's air from beneath. >You also have to worry about a blast of cold air, from an open door, >hitting the tube sheet, as that can cause warping, and will eventually >bring on leaky tubes. On my firedoors, I have a disk of metal that >rotates, and when it's in one position, it allows tiny holes to admit >air, in controlled amounts, to help with burning the hydrocarbons that >have left the fire bed in the smoke, but not allow a huge blast of cold >air to hit the tube sheets. When rotated the other direction, it closes >off the holes entirely, to seal the upper fire bed from external air >after the smoke is burned off. To adjust the firing rate, you are much >better off to have dampers, which are nothing more than a controlable >coor at the front and rear of the ash pan. If you do not want a big slug >of cold air to come up in the front of the fire, and by-pass the bulk of >th4e fire, plus cooling the tube sheet, you only open the front damper a >bit. Then opening the rear damper, allows the bulk of the air being >drawn in to pass through the bulk of the fire bed, supplying air where >you want it, when you want it to do so. You can get away with out >working dampers by just having the air openings in the front of the ash >pan, a bit smaller than the openings in the back. I have 3/4" scale >locos with both graduated openings, and working door type dampers. >Write to me off list if you'd like a sketch or more detailed verbal >picture. >Keith > >
