About Central Boilers Board •Contents Chapter Wise • Contents Regulation WiseIndian Boilers Act 1923
Reg. 201, Reg. 202
FLAT PLATES

Manholes and Mudholes in Flat Plates

Where a flat plate is flanged to stiffen it at a manhole or sighthole, to permit same working pressure as would be allowed upon an unpierced plate, the depth of the flange measured from the other surface shall be at least equal to -

(T x W)1/2  = depth of flange in inches                             Eqn. (38)

where
T = the thickness of the plate in inches, and

W = the minor axis of the hole in inches.

Reg. 202
STAYS

Solid screwed stays

For screw stays to combustion chambers and fire boxes and for longitudinal and cross stays the maximum working pressure for the stays is to be calculated from the appropriate one of the following two formulae :-

 W. P. = C (D - 1.28 / N)1/2 Eqn.(39) A

 W. P. = C x D12 Eqn.(40) A

where
W.P. = the working pressure in lbs. per square inch.

D = the diameter of stays over threads in inches,

D1 = the diameter of body of stay at its smallest part in inches

N = the numbers of threads of stay per inch,

A = the area in square inches supported by one stay for area to be supported by stays near tubes in firebox tube plates of locotype boilers, see Regulation 193(e).

C = 7100 for steel or special wrought iron screw stays to combustion chamber of fireboxes.

C = 8640 for steel longitudinal or cross stays fitted with nuts

C = 4700 for copper screws stays to fireboxes.

Where stays are made with enlarged ends and the body of the stay is smaller in diameter that at the bottom of the thread the working pressure shall be calculated from the second formula.

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