phere (keep in a bottle with a glass stopper), will turn slightly red. If a change in color is not apparent at once, it should be allowed to remain in the solution a few minutes and then carefully dried and compared with an unused sample.

Another method is to put into it a few drops of a chemical called methyl-orange. This methyl-orange gives a yellow color so long as the water is alkaline, but if turned pink, it shows that the water is acid, and therefore highly corrosive. This latter test is more sensitive than the litmus paper test, and should be used in preference.

A testing kit containing the graduated bottle and the solutions referred to, also strips of blue and red litmus paper, neatly packed in a padded box, is supplied by The Babcock & Wilcox Company with all boiler installations intended for salt water service.

CARE OF BABCOCK & WILCOX MARINE BOILERS

F

IRING.-The correct manner of firing boilers depends largely upon

the class and quality of the fuel. Coal can be divided roughly into three classes-anthracite, or hard coal; semi-bituminous; and bituminous, or soft coal. When anthracite coal is burned it should be spread evenly over the grate and a fire of uniform thickness maintained, which may be from 3 to 8 inches, depending on the intensity of the draft and size of the fuel. When stoking, half the grate should be covered at a time. In this way, complete combustion is promoted by the fire on the bright half of the grate.

Semi-bituminous coal, that is high in fixed carbon and low in volatile. matter, can be fired evenly on the grate or coked just inside the fire door under the reverberatory roof, and then spread back over the incandescent fuel beyond. The coking of the coal at the front of the furnace distills off the volatile gases which burn under the furnace roof before passing among the tubes forming the heating surface.

Bituminous coal, which contains a large percentage of volatile matter and a relatively small amount of fixed carbon, is best burned by stoking light and often and covering about one-quarter of the grate at a time. The fire should be from four to seven inches thick to obtain the best results.

CLEANING. The efficiency of boilers must be preserved by keeping the heating surfaces clean, both externally and internally. By means of a steam lance and a flexible hose, provided with the boilers, the soot may be almost entirely removed from the tubes, the lance being inserted through the dusting doors in the side casing. In this way the boilers may be cleaned without interfering with the stoking. On arriving in port, the boilers should be swept out, and all deposits of soot removed.

When time in port will permit, the hand hole plates opposite the tubes in the vicinity of the furnaces should be removed, and the interior surfaces examined and washed out; and, if any undue accumulation of scale has taken place, it should be removed by the spoon scrapers or wire brush.

Tubes have been known to blister and crack, and upon removal found to contain only an eggshell of scale thinly deposited over their entire inner surface. Had these tubes been closely examined, before removal, by means of an electric lamp or torch, a small laminated hummock of scale would have been discovered directly over the blister or crack. These small bunches are composed of flakes of scale that have become loosened from other parts of the boiler and carried with the circulation until dammed in some portion of the tube. As these bunches are loose, they may be easily dislodged by washing out with a hose. Scale burns are most likely to occur when the feed water contains sulphate of lime or when salt water is used for make-up feed.

If the water has a tendency to form a hard scale, such a scale should be removed with the tube scrapers provided. One thirty-second of an inch of scale is the maximum thickness that should be allowed upon the heating surface.

OWNERS: DULUTH & IRON RANGE RAILROAD. BABCOCK & WILCOX BOILERS, 550 INDICATED HORSE-POWER. BREAKING ICE IN DULUTH HARBOR

BLOWING OFF.-Boilers should be blown through the bottom blow valves, at least twice a day, and through the surface blow valve, or scummer, once a watch. Opening these valves wide and immediately closing them is usually sufficient.

Bottom blows should be used freely after the boilers have been standing with banked fires or quietly steaming. At such times blowing should be more frequently attended to, as the circulation is less active and there is more opportunity for scale-producing deposits to settle on the heating surface. REPAIRS.-In order to remove a tube, select a narrow ripping chisel from the tool box furnished with all installations, and slit both ends of the tube lengthwise to a depth a short distance beyond the tube seat; close the expanded portions in, and, after loosening, the tube can be driven out. Care should be taken not to mar the seat in the wrought-steel header into which the tube is expanded. The process of removing and renewing tubes is the same

PLUG EXTRACTOR

as that employed in Scotch boilers, but avoids the necessity of beading over as the ends are not exposed to the action of the flames, nor the tubes used as stays. To save time in cases of emergency, tubes may be stopped with a conical cast-iron plug supplied for the purpose. As the plug fits the tube, only a few raps with the hammer are necessary to make it tight. The large end of the plug is drilled and tapped, and may be easily withdrawn by the extractor, consisting of wrought-steel bridge, bolt and nut, furnished with the boiler. When tubes become defective, they are generally renewed as the time required is but a trifle longer than that of plugging.

The expanding of the tubes is performed in the usual manner with expanders and mandrils provided. In replacing any of the short tubes, or nipples, between the headers and mud drum, or headers and steam and water drum, care should be taken that the projecting ends are swelled with the expander. All tubes and nipples should extend beyond their expanded seats one-half an inch.

EXPANDER IN POSITION

STEAM PACKET "CHARLES NELSON"

OWNER: CHAS. NELSON, SAN FRANCISCO, CAL. BABCOCK & WILCOX BOILERS, 850 INDICATED HORSE-POWER

TESTS OF BABCOCK & WILCOX MARINE BOILERS

Τ

HE object of testing a steam boiler is to determine the quantity and quality of steam it will supply continuously and regularly, under specified conditions; the amount of fuel required to produce that amount of steam, and sometimes sundry other facts and values. In order to ascertain these things by observation, it is necessary to exercise great care and skill, and employ the most perfect apparatus, or errors will creep in sufficient to vitiate the test and render it of no value, if not actually misleading.

The principal points to be noted in a boiler test are:

Ist. The type and dimensions of the boiler, including the area of heating surface, steam and water space, and draft area through or between tubes. 2d. The style of grate, its area, with proportion of air space therein; height and size of funnel; area of up-take, etc.

3d. Kind and quality of fuel; if coal, from what mine, etc.; percentage of refuse and percentage of moisture in fuel. The latter is a more important item than is generally understood, as in adding directly to the weight, it introduces an error in the final results directly proportioned to the per cent. of the fuel.

4th. Temperature of feed water entering boiler, and temperature of escaping gases. The temperatures of fire room and of external air may be noted, but are usually of slight importance.

5th. Pressure of steam in boiler, draft pressure in furnace, at boiler side of damper, in up-take connection with funnel, and the pressure of the blast, if any, in the ash-pit or stoke hold.

6th. Weights of feed water, of fuel and of ashes. Water meters are not reliable as an accurate measure of feed water.

7th. Time of starting and of stopping test, taking care that the conditions are the same at each, as far as possible.

99 66

8th. The quality of the steam, whether "wet, dry" or superheated. From these data all the results can be figured, giving the economy and capacity of the boiler, and the sufficiency or insufficiency of the conditions, for obtaining the best results.

For purposes of comparison with other tests, the water actually evaporated under the observed conditions per pound of coal and combustible and per square foot of heating surface per hour are reduced to "equivalent evaporation" from and at 212 degrees. (See page 86.)

The standard boiler horse-power is equal to 341⁄2 pounds of water evaporated per hour from and at 212 degrees. The modern marine engine, however, uses only about half a boiler horse-power for each indicated horsepower, and any calculation of the former quantity is of little use for marine

purposes.