NOZZLES.
The sizes of nozzles named below will give the most satisfactory results, those in italics being the ones best adapted for fire duty. Also see page [93] for standard sizes of steam fire engines and page [117] for table of effective Fire Streams.
1, Extra first size engine.—1,100 to 1,150 gallons capacity. Through short lines of hose: One 11⁄2-inch smooth-bore nozzle, for one stream; one 13⁄4-inch ring nozzle, or one 2-inch ring: nozzle; 15⁄16-inch ring nozzles for two streams. With 1,000 feet of hose, one 15⁄16-inch ring nozzle.
2, First size engine.—900 to 1,000 gallons capacity. Through short lines of hose: One 13⁄8-inch smooth-bore nozzle, for one stream; one 11⁄2-inch ring nozzle, or one 15⁄8-inch ring nozzle; 11⁄4-inch ring nozzles for two streams. With 1,000 feet of hose, one 11⁄4-inch ring nozzle.
3, Second size engine.—700 to 800 gallons capacity. Through short lines of hose: One 11⁄4-inch smooth-bore nozzle, for one stream; one 13⁄8-inch ring nozzle, or one 11⁄2-inch ring nozzle; 11⁄8-inch ring nozzles for two streams. With 1,000 feet of hose, one 11⁄8-inch ring nozzle.
4, Third size engine.—600 to 650 gallons capacity. Through, short lines of hose: One 11⁄8-inch smooth-bore nozzle, for one stream; one 11⁄4-inch ring nozzle, or one 13⁄8-inch ring nozzle; 1-inch ring nozzles for two streams. With 1,000 feet of hose, one 1-inch ring nozzle.
5, Fourth size engine.—500 to 550 gallons capacity. Through short lines of hose: One 11⁄16-inch smooth-bore nozzle, for one stream; one 11⁄8-inch ring nozzle, or one 11⁄4-inch ring nozzle; 7⁄8-inch ring nozzles for two streams. With 1,000 feet of hose, one 1-inch ring nozzle.
6, Fifth and sixth size engines.—300 to 450 gallons capacity. Through short lines of hose: One 1-inch smooth-bore nozzle, for one stream; one 1-inch ring nozzle, or one 11⁄8-inch ring nozzle, 7⁄8-inch ring nozzles for two streams. With 1,000 feet of hose, one 7⁄8-inch ring nozzle.
The Ahrens steam fire engine is not presented as a whole, but Figs. [426]-[428] show parts of this interesting and widely known apparatus.
Fig. 426.
The boiler, Fig. [426], is radically different from others, and the special features making it so popular in the past are the absence of a crown sheet and smoke flues, coupled with the advantageous manner in which the water-tube coil sections can be withdrawn from the containing shell of the boiler. The peculiar arrangement of the tubes compels a forced circulation of the water, and for which purpose an independent steam pump is provided. Water drawn from the fire-box leg is forced through the water tubes, and this relation between the circulating pump and the other elements of the boiler will be more readily understood by reference to the illustrations, where Fig. [426] is a sectional, [427] a top, and [428] a bottom view.
Fig. 427.
Fig. 428.
Fig. 429.—See page [141].