7650 Banks St. Justice, Illinois 60458
Now that I have lived through line 4, schedule C, plus line 2, schedule B, add together and pay . . .
By drinking about 30 cups of basil tea brewed from water strained from oat seed, I should be tranquilized enough to get back into life's regular common grind. First, I would like to thank the ones who wrote me letters asking how to fix their boilers. I hope I was able to help them. Anyone may write to me and I will do what I can for them. Let's see, where were we when I left off? Oh yes, you were standing in the fire box knee deep in hot coals, watching the combustion 'closely,' and wondering why the smoke wasn't going through the flues.
At this time, I will try to explain the best method of firing coal to get the least amount of smoke. I said before it is difficult because a person has a desire to put too much coal in a fire at once. Let us at this time pick a size boiler. Let's say 20 hp., that's a good size to work from. Our fire box is 42' long, 28' wide, and 35' deep. We draw a line down the center of it and it is 14' wide, so we will say 12' for round figures. Now we have 3 sq. ft. of grate to work from. Don't forget the little thermo cap for the smoke stack we talked about a few months back. It will help build up a draft. We build a fire on the one side of the fire box only. Slowly adding coal and giving it good draft in order to keep the smoke down as much as possible. When we get enough steam for the blower, we remove the thermo cap and use the blower.
If you do have some coke, now is a good time to put some in and let it get hot, for we have a good draft and it will soon catch. Of course, you could use anthracite or hard coal. Hard coal makes a hot local fire with little flame, and a limit to the value of additional tube surface is soon reached. When fire is hot, fill the other side with coal, small amount at a time, and the fire will burn the gasses as they escape from the volatile matter. Fill this side up well above the fire level of the burning side; by the time it has coked good and is burning clean, the other side has burned out and you can clean it down to the grates. You should burn from 10-15 lbs. of coal per hour, per sq. ft. of grate.
Now remember, I figure the boiler a full capacity, but at a show you may not fire that heavy unless you are working your engine. If you choose to burn coke, you can top off your fresh coal with a few shovels after each fill of coal. You say how much heat will we get at this method of firing? Well, let's see. Let's forget the hydrogen as we know is 62,000 units of heat per lb., and work on carbon only.
If it takes 965.7 units to evaporate one pound of water, 212 degrees that is. 1 lb. of carbon 14,500 units would evaporate 14,500 divided by 965.7 = 15 lbs. water. We are using 10 lbs. per sq. ft. grate per hour. We figured only 3 sq. ft. 10 x 3 x 15 = 525 lbs. per hr. That's enough to keep the water boy running. Let's see now, what is the hp. we are running right now on the boiler. That is 30 lbs. per hr. at 100 degrees F. to steam 70 lbs. on gauge. That is 17 hp. Not bad for a 20 hp. boiler and half its grate. We can increase the draft and burn more coal and get more from it if you need it.
I feel that we can go by this method and make a good show for the public. It will take a little time and effort to operate under this method, but the results are what counts. I wonder just what this boiler could do if it had to, also what it could do if forced.
Now what have we got 20 hp.? That would be shell dia. 32'. 52 tubes, 2'x 84', we have 7 sq. ft. of grate. We will not consider the heating surface because we know it was engineered to its highest point of efficiency. Therefore, if we fire it full grate and the same amount of air, we could develop 35 hp. Now if we increase the amount of coal fed and we increased the amount of air supplied, such as using a blower, we automatically increase the horsepower. Therefore, we can check our calculations and say if air is fed; say 1,500 c.f.m. and fuel fed about 200 lbs. per hour, and we catalize our fuel, we can very easily develop approx. 200 hp. from a boiler this size. But we must not forget the feed water, that is for sure. I have fired boilers, and seen others fired to the extent where the fire was coming out of the first pass tubes and going in the second pass. And I know they could have been fired much harder. Many rules differ on the horsepower of boilers. Another rule for example is the amount of water a boiler would evaporate, in pound per hour it received feed water at 212 degrees F. The evaporation of 34.5 pounds of water per hour from 212 degrees F. which is equivalent to a heat output of 970.2 x 34.5 = 33,471.9 b.t.u. per hour.
Next time we get together we will have a general talk, as I wish to answer questions that have been asked me in the past.