TABLE 4.—Dimensions of Boilers Nos. 1, 2, and 3.
| Items. | Boiler No. 1. | Boiler No. 2. | Boiler No. 3. |
|---|---|---|---|
| Distance, outside to outside of boiler heads, in inches | 8.28 | 8.28 | 16.125 |
| Actual outside diameter of flues, in inches | 0.252 | 0.313 | 0.252 |
| Actual inside diameter of flues, in inches | 0.175 | 0.230 | 0.175 |
| Number of flues (tubes) | 10 | 10 | 10 |
The work on the first three boilers is only a beginning; preparations are being made to test eight more multi-tubular boilers of various lengths and tube diameters, under similar conditions. Because of the experience already obtained, it will be necessary to make only eight tests at each initial air temperature.
When the work on multi-tubular boilers is completed, water-tube boilers will be taken up, for which a fairly complete outline has been prepared. This second or water-tube portion of the investigation is really of the greater scientific and commercial interest, but the multi-tubular boilers were investigated first because the mathematical treatment is much simpler.
Producer-Gas Tests.—The producer-gas plant at the Pittsburg testing station is in charge of Mr. Carl D. Smith, and has been installed for the purpose of testing low-grade fuel, bone coal, roof coal, mine refuse, and such material as is usually considered of little value, or even worthless for power purposes. The gas engine, gas producer, economizer, wet scrubber (Fig. 1, [Plate XIX]), and accessories, are in Building No. 13, and the dry scrubber, gas-holder, and water-cooling apparatus are immediately outside that building (Fig. 2, [Plate XIX]).
Fig. 1.—Gas Producer, Economizer, and Wet Scrubber.
Fig. 2.—Producer Gas: Dry Scrubber and Gas Holder.