The Dürr Water-Tube Marine Boiler
This boiler consists of a vertical water-chamber, divided into two parts by a diaphragm plate, and communicating with a steam and water-drum. The back of the water-chamber forms the tube-plate of a number of generating-tubes, 3.25 inches diameter and 9 feet long, having their lower ends closed and supported in such a manner as to permit free expansion. Internal circulating-tubes, attached to the diaphragm plate, extend nearly to the ends fo the generating-tubes, and have open ends.
The water flows from the steam and water-drum down the front half of the water-chamber through the circulating-tubes, and the steam and water flow from the steam-generating tubes through the back half of the chamber and rise up through it to the steam and water-drum.
A superheater is formed semi-circularly round the steam and water-drum, and is provided with a double chamber and concentric tubes, similar to the generating-tubes of the boiler. The total heating-surface of the boiler is 2,594 square feet, and the area of the fire-grates is 54 square feet. The weights are:--boiler, 12.33 tons; casing, 3.27 tons; fittings, 3 tons; brickwork, 1.18 tons; water, 5.07 tons; the total weight being 24.85 tons. The capacity of the steam-space is 70.6 cubic feet. The boiler is suitable for supplying steam to triple-expansion engines of 576 indicated horsepower with natural draught, and 1,115 indicated horse-power with a moderately forced draught.
-- Walter S. Hutton, Steam-Boiler Construction: A Practical Handbook (London: Crosby, Lockwood, 1903).
Isometric drawing of a Dürr boiler.
One of many German warships to rely on the Dürr boiler was SMS Yorck, armored cruiser of 1905.