Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . as utility, as itcosts no more to make a well-shaped cowl than it does tomake a poor one. In the annexed sketches are presented a group of six cowls,and a very simple method of determining their outlines fromthe diameters of their bases, and the development of thepatterns for their construction. In Fig. 3, the group of cowlsis shown, ranging from 4 inches to 14 inches diameter of the center line of the cowl will be found, and an
Laying out for boiler makers and sheet metal workers; a practical treatise on the layout of boilers, stacks, tanks, pipes, elbows, and miscellaneous sheet metal work . as utility, as itcosts no more to make a well-shaped cowl than it does tomake a poor one. In the annexed sketches are presented a group of six cowls,and a very simple method of determining their outlines fromthe diameters of their bases, and the development of thepatterns for their construction. In Fig. 3, the group of cowlsis shown, ranging from 4 inches to 14 inches diameter of the center line of the cowl will be found, and an equal dis-tance between the points H and A, will give the centers fora corresponding curve below the center line. Extending theline of the axial plane through the cowl, the points of inter-section with the perpendicular line through the center of thebase will give the base line of the cowl, with a proportionalamount of straight part to receive the usual fittings. In the line c f the axial plane cuts the center of the base ofeach cowl. In laying out a group of cowls for a ship, first establishthe axial plane from the largest cowl in the series. From this. FIG. I. -SIDE VIEW OF COWL. SHOWIXG METHOD OF THESIDE FIG. -FRONT VIEW OF COWL, SHOWING THE WORKING INTHE PATTERN SHEET. base. It can be readily seen that their curves and diametershave a relative proportion to each other. In Fig. 4 is shownthe method of obtaining the outlines from the diameter ofthe base. The throat line is first determined, its radius be-ing taken as one-fourth the diameter of the base. Thus the cowlin Fig. 5 is 14 inches in diameter at the base, and the radiusof the throat is y/t inches. This is the largest cowl of thegroup shown in Fig. 3. In developing the further outline,draw in the throat and project a line parallel to the base, asfrom E to C. With ^ as a center, draw an arc tangent to theperpendicular line through the center of the base and cuttingthe horizontal line
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Keywords: ., bookcentury1900, bookdecade1900, bookidl, booksubjectsteamboilers
