  About Central Boilers Board •Contents Chapter Wise • Contents Regulation WiseIndian Boilers Act 1923 Reg. 207
STAYS

Gusset Stays

The maximum working pressure for gusset stays shall be calculated by the following formula :

 W. P. = 9000 x C Eqn.(42) A

C the co-efficient, is the number representing the least of the following: -

1) N1 x A1,
2) N2 x A2 x 1.875,
3) N3 x A3 x 1.875
4) N4 x A4
5) ( G - N2 D2 ) x ( t - 2 ) x .037,
6) ( G1 - D3 ) x ( t - 2 ) x .037

N1, N2, N3, N4, D1, D2, D3, D4 and A1, A2, A3, A4 are respectively the numbers, diameters and sectional areas of the rivets in the joints of each gusset stay, only rivets in the supported area, to be considered effective, the order of the joints being, (1) angles to end plate, (2) end plate angle to gusset, (3) shell angles to gusset, and (4) angles to shell.

G is the depth in inches of gusset plate measured through the line of rivet attaching it to the end plate angles.

G1 is the depth in inches of gusset plate measured normal to the slant edge of plate through the rivet nearest to the end plate in the joint attaching gusset plate to shell angles.

t is the thickness of the gusset plate in 32nds of an inch.

A is the area in square inches of flat plate supported by the gusset edge of plate through the rivet nearest to the end plate in the joint attaching as follows :-

(a) The margins allowed under flat plate regulations for shell and furnace shall be marked on end plates and the lengths of the centre lines of gussets between them measured, also the distance between each pair of gusset lines from the middle of the smaller in a direction normal to the greater. If L and L1, be the length of two adjacent gusset lines and if the distance between them be W, the area contained by the gusset lines and the shell and furnace margins lines may be apportioned between the stays thus :

 W ( 3L + L1 ) = Portion of area in square inches, apportioned to L line gusset Eqn.(43) 8

 W ( 3L1 + L ) = Portion of area in square inches, apportioned to L1, line gusset Eqn.(44) 8

(b) The portion of the area on the other side of each gusset line shall except when of triangular form, be found in like manner and its amount added to that already found to form the total.

(c) For the triangular portions in the wing spaces the area shall be taken as half the product of the length of gusset line into the perpendicular distance between it and the intersecting point where the marginal curves meet.     About Central Boiler Board Foreword • List of Amendments Ibr Forms • Home • Search • Help • Contact Us