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Stewart's Rapid Cupola

This cupola embodies the principle of tall stacks and small diameter, which now seem to be gaining favor as fuel-savers, being, according to reports, far more economical than low ones of large diameter, which are now so common almost everywhere. The principal dimensions of a Stewart Rapid Cupola capable of melting 7 to 10 tons of thoroughly mixed and very hot iron per hour is as follows:

Ft. n. Outside of ordinary shell.... 7 0 diam. Outside of chimney.... 6 0 diam. Outside of air-belt.... 9 2 diam. Outside of receiver.... 4 0 diam. Inside of receiver.... 2 6 diam. Inside of cupola-lining at tuyeres.... 2 11 diam. Inside of charging-door.... 5 3 diam. Inside of at chimney.... 4 3 diam. Total height of cupola proper (exclusive of top bracket).... 46 0 diam. To the extreme top of bracket.... 52 0 diam. Height from ground level to charging-platform 22 0 diam. Height from charging-platform to sill of charging-door.... 2 0 diam. Height of air-belt.... 3 3 diam. Height of receiver-shell.... 3 9 diam. Height from ground-level to tapping-hole.... 3 3 diam. Area of outlet-chimney (inside of lining).... 3 6 square Outside size of chimney.... 4 9 square Capacity of receiver (molten meta).... 2 tons The cupola is fixed upon a strong cast-iron base-plate 7 feet 6 inches square by 3 inches thick. This base-plate is cast in halves across the corners, so as to allow of expansion with the cupola-shell. It is supported by four cast-iron columns 5 feet long by 10 inches in diameter, which are bolted to the cast-iron base-plate. The cupola base-plate is provided with a wrought-iron hinged drop-bottom door, which is also in halves, opening from the centre of base-plate. There are three rows of tuyeres to supply zones of oxygen, necessary for a thorough combustion of the fuel, enclosed in the air-belt, each zone acting independent of the others. A chief feature in this cupola is the brick-lined receiver for the melted metal, by which means the heat is retained and oxidation prevented, while the blast-pressure maintains an agitation conducing to a thorough mixing together of the various kinds of metal entering into the charge. The waste heat is utilized by passing up a gannister-lined pipe entering the cupola just above the air-belt. This cupola is hooded, an escape for waste gases being regulated by a flap-door at the side. The charging-platform is entirely constructed of wrought-iron crossed beams and plates, the joints of the plates being carefully planed and the plates riveted to the girders to insure perfect safety to the workmen below and above. This platform has an area over 1200 superficial feet, and is covered by a wrought-iron roof with provision for lighting and ventilation. The platform is connected with a hydraulic hoist.

Stibnite, or Sulphuret of Antimony, is the ore from which the antimony is obtained. It is found in primitive and secondary rocks associated with sulphurets of lead and zinc, and with ores of copper, iron, and arsenic. Its composition is antimony 74, sulphur 26. Lead, gray in color, occurs massive, composed of delicate threads closely aggregated, and sometimes so fine as to resemble wool. See ANTIMONY.