479
OF ENGINEERING FORMULÆ.
Collapsing Pkessuke in Cylindrical Boiler Flues.
P = Collapsing pressure in lbs. per square inch.
t — Thickness of plate in inches.
L = Length of tube or flue in feet,
D = Diameter of tube in Inches.
«219
P = 806,300 -j-jj • (Fairbairn.)
= Approximately 0- when k = 800 in |-ln. plate ;
L D
k = 820 in J-in.; k = 840 in i in.; k — 860 in i-in.
plate,
Unwin’s Formula for the Collapse of Boilers.
For tubes with longitudinal lap joint,
«21
P = 7,363,600 lo 91)l-lö '
For tubes with longitudinal butt,
«2-21
P = 9,614,000 L0.a px-ie'
For ordinär boiler flues with longitudinal and cross Joints,
(2-35
P = 15,547,000 •
~ i3 A
Approximate formula, P = .
Values of A, B, and C.
WhentiS? ,061& .087& ,n9& ,159& .206& -261 & -325 & -399
between 1
Then A = -40 -45 -50 -55 -60 -65 -70
When/is I .399& .483& .5M & .6s2& -80 & -931& 1-07
between f
Then A = •’75 -80 -85 -90 -95 1-0
When L is ) 13 & 25 & 51 & no & 253 & 628
between J
Then B= «75 -7 -65 '6 '55
WhenDls) 2-4&4-0 & 6'5 & 10'2 & 15'5&22-9 & 33'0 & 47
between J
ThenC = 1'2 1-3 1-4 1-5 1’6 1-7 1-8