FIG. 1 - ELEVATION.
At a recent meeting of the Industrial Society of Amiens, Mr. Schmidt, engineer of the Steam Users' Association, read a paper in which he described the process employed in the construction of a large chimney of peculiar character for the Rocourt distillery, at St. Quentin.
This chimney, which is cylindrical in form, is 140 feet in height, and has an internal diameter of 8½ feet from base to summit. The coal consumed for the nine generators varies between 860 and 1,200 pounds per hour and per 10 square feet of section.
The ground that was to support this chimney consisted of very aquiferous, cracked beds of marl, disintegrated by infiltrations of water from the distillery, and alternating with strata of clay. It became necessary, therefore, to build as light a chimney as possible. The problem was solved as follows, by Mr. Guendt, who was then superintendent of the Rocourt establishment.
Upon a wide concrete foundation a pedestal was built, in which were united the various smoke conduits, and upon this pedestal were erected four lattice girders, C, connected with each other by St. Andrew's crosses. The internal surface of these girders is vertical and the external is inclined. Within the framework there was built a five-inch thick masonry wall of bricks, made especially for the purpose. The masonry was then strengthened and its contact with the girders assured by numerous hoops, especially at the lower part; some of them internal, others external, to the surface of the girders, and others of angle irons, all in four parts.
FIG. 2 - HORIZONTAL SECTION.
The anchors rest upon a cast iron foundation plate connected, through strong bolts embedded in the pedestal, with a second plate resting upon the concrete.
As the metallic framework was calculated for resisting the wind, the brick lining does not rest against it permanently above. The weight of the chimney is 1,112,200 pounds, and the foundation is about 515 square feet in area; and, consequently, the pressure upon the ground is about 900 pounds to the square inch. The cost was $3,840.
The chimney was built six years ago, and has withstood the most violent hurricanes.
The mounting of the iron framework was effected by means of a motor and two men, and took a month. The brick lining was built up in eight days by a mason and his assistant.
A chimney of the same size, all of brick, erected on the same foundation, would have weighed 2,459,600 pounds (say a load of 3,070 pounds to the square inch), and would have cost about $2,860.
FIG. 3 - VERTICAL SECTION OF THE CHIMNEY.
The chimney of the Rocourt distillery is, therefore, lighter by half, and cost about a third more, than one of brick; but, at the present price of metal, the difference would be slight. - Annales Industrielles.