. Tentative revised boiler safety orders. -eaV- Lonofitucf/nff/ Line Fig. 11 Example of Tube Spacing with Pitch of Holes. Varying in Every Second and Third Eow c The strength of those ligaments between the tube holes whichare subjected to a longitudinal stress shall be at least one-half therequired strength of those ligaments v^hieh come between the tubeholes which are subjected to a circumferential stress. 48 REPORT OP BOILER CODE COMMITTEE, 193 When a shell or drum is drilled for tube holes so as toform diagonal ligaments as shown in Fig. 12, the efficiency of theseligaments shal
. Tentative revised boiler safety orders. -eaV- Lonofitucf/nff/ Line Fig. 11 Example of Tube Spacing with Pitch of Holes. Varying in Every Second and Third Eow c The strength of those ligaments between the tube holes whichare subjected to a longitudinal stress shall be at least one-half therequired strength of those ligaments v^hieh come between the tubeholes which are subjected to a circumferential stress. 48 REPORT OP BOILER CODE COMMITTEE, 193 When a shell or drum is drilled for tube holes so as toform diagonal ligaments as shown in Fig. 12, the efficiency of theseligaments shall be, that given by the diagram, Fig. 13. In this diagram the abscissae are —r- and the ordinates—, where p = longitudinal pitch of tube holes, or distance between centers of tubes in a longitudinal row, ^= diagonal pitch of tube holes, = diameter of tube holes, in. To use the diagram. Fig. 13, the values of —- and — are com- d p. Longitudinal Line Fig. 12 Example of Tube Spacing with Tube Holes on Diagonal Lines puted and the efficiency for the corresponding point is read off fromthe diagram. Should the point fall above the curve of equalefficiency for the diagonal and longitudinal ligaments, the longi-tudinal ligaments will be the weaker, in which case the efficiencyis computed from the following formula: p — d (1) V Examples: 1st, diagonal pitch of tube holes in drum as shownin Fig. 12 — in. Diameters of holes = 4 %2 iii-Longitudinal pitch of tube holes = lli/^ in. p _ dP -= = p
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectsteambo, bookyear1919
