Nigel, could you enlighten me as to what a fire tube is? I understand flues. I understand superheater flues. I understand thermic syphons. But I am kind of fuzzy as to what a fire tube is and what differentiates it from the other steam engine thingy's. Thanks.
It may be my British origin or just questionable terminology.
I am using it to identify the small tubes as opposed to the super heater flues so the total that we have to re-install is 16 super heater flues and 180 fire tubes / small tubes.
Fire tubes have to do specifically with the boiler. There are two types of boilers, fire tube and water tube. In a fire tube boiler, there is an area in which you have the fire. The heat and the smoke then travel through the tubes heating the water that surrounds the flues. When it goes though the tubes the smoke is then exhausted out. In water tube boilers, there is a central heat source. Then around the heat source on two sides is water with flues going between them. Water travels from one side to another over the heat source to create steam. The heat and smoke is exhausted out above the heat source. Now back to steam locomotives, they are fire tube boilers. The fuel is burned in the fire box where it heats the water between the wrapper sheet, back head, rear tube sheet, and the crown sheet. It then sends the smoke and heat through the flues, heating the water that is between the courses, the flues, and the two tube sheets. The smoke is then sent out the smoke stack. You don't actually call the flues fire tubes. You just call them flues.