Figure and Dimensions.-Above ground the chimney is a frustum of a cone, with a straight batter. Underground there is a plinth or basement, octagonal outside at the ground line, and square at the bottom; cylindrical inside, and pierced with four circular openings for flues. Height of chimney above the ground, 250 feet. Total height from foundation to top, 267 feet. Inside diameter at top of cone, 13 feet. Inside diameter, two feet above bottom of cone, 21 feet 10 inches. Inside diameter in basement, 18 feet 10 inches. Inside diameter of archway for flues, 7 feet 6 inches. Outside diameter at top of cone, 15 feet 3 inches. Outside diameter 2 feet above bottom of cone, 25 feet 7 inches. Outside dimensions of square basement, 30 feet × 30 feet. Size of foundation course, 31 feet 6 inches x 31 feet 6 inches. Size of concrete foundations, 34 feet 6 inches x 34 feet 6 inches, and 3 feet thick. Thickness of Brickwork.-First two feet above foundation stepping from 4 bricks to 2 bricks; next 88 feet, 2 bricks; next 80 feet, 2 bricks; remaining 80 feet, 1 bricks. The pressure on the ground below the concrete is 1.6 tons on the square foot. Fire-brick Lining.-The thickness of brickwork given above included the fire-brick lining, which was one brick in thickness in the first 90 feet, and brick the remaining height, the firebrick being bonded in with the common brick, but being laid in fire-clay. This method of construction was considered better than that of the inner cone. Strips of No. 15 hoop iron, tarred and sanded, were laid in the bed-joints of the cone at intervals of 4 feet in height, with their ends turned down in the side-joints. The length of the iron was twice the circumference of the chimney. Cap and Lightning Conductor. - On the top of the chimney is a pitch-coated cast-iron curb, one inch thick, coming down three inches on the outside and inside. The lightning conductor is a copper wire rope three-fourths inch in diameter. It terminates in a covered drain, in which there is always a sufficient run of water. 66 "Jumbo" Chimney of the Merrimack Manufacturing Company, Lowell, Mass.-This chimney was built in 1882. It is a round chimney: height from the surface of the ground, 282.75 feet; diameter of base, 28 feet; diameter of the narrowest part near the top, 15 feet: diameter of flue, 12 feet; the amount of staging used was 28,000 feet; the number of brick used, 1,050,000. The chimney is surmounted by a cast-iron cap of over nine tons weight, its largest diameter being 21 feet. It is protected from lightning by a three-fourths inch cable conductor with two tips. The chimney was built to accommodate 16 nests of upright Corliss boilers of 300 H. P. per nest, and its sole use is to furnish the necessary draught and convey away the smoke from these boilers. The chimney was planned and engineered by J. T. Baker, C.E., at that time for the Merrimack Company. A full description of this chimney, with plans and elevation, was published in the Transactions of the American Society of Civil Engineers for April, 18-5, No CCCI. The Pacific Mills Chimney at Lawrence, Mass.This chimney was built by Mr. Hiram F. Mills, C.E., in 1873, and consists of an outside octagonal shell 222 feet high above the ground, with a distinct interior core 8 feet 6 inches in diameter inside, extending one foot above the top of the outer shell, and 11 feet below the ground. The chimney is founded 19 feet below the ground, upon coarse sand, the foundation being 35 feet square, enclosed by pine sheet-piling. The base is concrete, I foot thick, then rubble masonry of large pieces of granite in cement, this stone-work being 7 feet high. Upon the stone-work is placed the brick chimney, the outer shaft being at the base 20 feet wide, and at the top, under the projecting cornice, 11 feet 6 inches wide. This brickwork is 28 inches in thickness at the base; at 12 feet in height it becomes 24 inches, which continues 18 feet; then 20 inches for 20 feet; then 16 inches for 40 feet; then 12 inches for 60 feet; then 8 inches to the top. The top of the chimney is of cast-iron plates inch thick. The horizontal flue entering the chimney is 7 feet 6 inches square. The inside vertical flue of the chimney is a cylinder 8 feet 6 inches in inside diameter, and 234 feet high, with walls 20 inches thick for 20 feet, 16 inches thick for 17 feet, 12 inches thick for 52 feet, and 8 inches thick for 145 feet. The foundations were laid in mortar of Rosendale cement and sand, the outer shell in mortar of Rosendale cement, lime, and sand, and the flue-walls in mortar of lime and sand. During the winter of 1873, the flue being 90 feet above the ground, the boilers, having 452 square feet of grate surface, were connected with the chimney with satisfactory results. Between June and September, 1874 the chimney was finished. The approximate weight of the chimney is 2,250 long tons, the number of bricks being about 550,000. The chimney is opposite the middle of a line of 28 boilers, and 210 feet distant from them. It was designed to serve for boilers having 700 square feet of grate surface, burning about 13 tons of anthracite coal per hour. The chimney was struck by lightning in June, 1880, after which date a lightning-rod was put up, which consists of a seamless copper tube" thick, 1 inch inside diameter, at the top of which are 7 points radiating from a ball 4 inches in diameter, the top of the central point being 8 feet above the iron cap. The rod is attached to the chimney by brass castings, and is connected at the bottom to a 4-inch drain-pipe extending 60 feet to a canal. Chimney near Freiberg, Saxony.-Supposed to be the highest in the world (1891). It is 460 feet high, 33 feet in diameter at its base, and 16 feet at the top, its inner diameter being 8 feet. It is built throughout of massive claystone with a facing of markstone at its base. 1 Wrought-iron Chimneys. 1—“ Wrought-iron shafts have found great favor in America and Russia, but in England and the Continent generally, as far as we have been able to ascertain, they are an exception. In addition to the wrought-iron shafts detailed in this paper we have been informed of the following: Messrs. Witherow & Gordon, of Pittsburgh, Penn., U. S. A., have, since 1876, built upward of thirty wrought-iron shafts, varying in height from 100 feet to 190 feet, and from 5 feet to 9 feet in diameter. The firm write us that these shafts answer admirably the purpose for which they were built. Mr. L. S. Bent, Superintendent of the Pennsylvania Steel Company, Steelton, Penn., U. S. A., states that his company have the following eight wrought-iron shafts in use, and have found them both durable and economical: No. 1, 170 feet high, 6 feet 6 inches diameter, built 1881 "They are lined for 30 feet with 9-inch fire-brick, and the remainder of height with 4-inch red brick. The Ravensdale Iron Works chimney-shaft, Tunstall (Messrs. Robert Heath & Sons), is a circular wrought-iron shaft not spread at its base. Its height from ground-line to top is 75 feet; outside measurement at ground sur 1 R. M. & F. J. Bancroft, Tall Chimney Construction. face, diameter, 6 feet; ditto at top, diameter, 6 feet. Seventy-five wrought-iron plates were used in the construction of this shaft, the thickness being inch. The plates have a lap of 24 inches, and are riveted together with 3-inch cup-headed rivets. The shaft is lined its entire height with fire-brick. The shaft carries off the fumes from three boilers. The wrought-iron chimney of Messrs. Francis & Co., of the Nine Elms Cement Works, Cliffe Creek, Rochester, was erected in 1878. It was designed by Mr. V. de Michelle, C. E., and constructed by Messrs. Fielding & Platt, Gloucester. The shaft is circular and parallel throughout, and is constructed of wrought-iron plates. The plates vary in thickness downward from inch to inch. Its height from ground-level to top is 160 feet; external diameter throughout, 5 feet; internal diameter throughout, 4 feet 6 inches. It is lined with three-inch firebrick its entire length. The chimney is stayed against the wind by four 33-inch steel guy-ropes. This chimney was erected over the central one of a row of nine cement kilns, which are all connected to shaft by a wrought-iron horizontal flue four feet in diameter. Two additional ones have since been added, and the chimney now carries off the gases from eleven cement kilns. Round the outside of central kiln on ground-level is fixed a cast-iron curb or baseplate. On this base stand four cast-iron standards or supports having their lower ends butting on to and secured to base-plate. The standards incline inward until their upper ends meet to support a cast-iron circular chimney-base, which forms the top of the central kiln. The wrought-iron chimney proper commences from top of this circular cast-iron base, directly over which the 4-foot horizontal flue is connected to shaft. For the construction of this chimney a timber stage was erected at the level of the kiln tops, and upon this stood the rivet fires. Four winches were worked on this stage, and to them were led guy-ropes, after passing round blocks at convenient distances. A hydraulic press, with a 4-foot stroke, was then fixed over the central kiln, and the top length of 20 feet, which had previously been riveted-up on the ground, and raised to the stagelevel, was placed upon the ram. The ram was then pumped up, and the 20-foot length raised a height of 4 feet, the guy-ropes being slackened out to the required extent, as the 20-foot length gradually A 4-foot ring of plating was then riveted on with 3-inch snaphead rivets and the usual lap, the ram was then again pumped up, and the now 24-foot length raised the necessary height; another ring of plates was then riveted on, and the operation repeated until the chimney had reached its required altitude. The cost of this chimney was about £1,000, including long wrought-iron flues." rose. FLOW OF GAS IN PIPES. [From Haswell's "Engineers' and Mechanics' Pocket-Book."] The flow of gas is determined by the same rules as those governing the flow of water. The pressure applied is indicated and estimated in inches of water. DIAMETER AND LENGTH OF GAS-PIPES TO TRANSMIT GIVEN VOLUMES OF GAS TO BRANCH PIPES. The volumes of gases of like specific gravities discharged in equal times by a horizontal pipe under the same pressure, and for different lengths, are inversely as the square roots of the lengths. The loss of volume of discharge by friction, in a pipe six inches in diameter and one mile in length, is estimated at ninety-five per cent. Gas Memoranda. In distilling fifty-six pounds of coal, the volume of gas produced in cubic feet, when the distillation was effected in three hours, was 41.3; in seven hours, 37.5; in twenty hours, 33.5; and in twentyfive hours, 31.7. A retort produces about six hundred cubic feet of gas in five hours, with a charge of about one and a half hundred-weight of coal, or 2,800 cubic feet in twenty-four hours. A cubic foot of good gas, from a jet one-thirty-third of an inch in diameter and a flame of four inches, will burn sixty-five minutes. Internal lights require four cubic feet, and external lights about five cubic feet, per hour. When large or Argand burners are used, from six to ten cubic feet will be required. |