The Sun.
London, England, 1858-11-02 00:00:00

PATENT STEAM BOILER.

(From. the Derby Reporter of October 29, 1858.)
We have been much pleased with an inspection
of a patent boiler, made at the locomotive works of
the Midland Railway Company here, which appears
to be a step in the right direction. The ordinary
way of making boilers is by bending plates of a
uniform thickness to the required circle, and strongly
riviting them together round the edges, and where
connected to flat ends, angle irons of a strong sec•
tion are introduced. Up till a very recent date it
was believed that the rivetted portion of the boiler
was as strong as any other part of it, but the prac-
tical experiments of Mr. Fairbairn demonstrated
that if the strength of an ordinary boiler plate
was assumed to be 100, then a joint secured by
a single row of rivets was equal to 56, and, it
double rivetted, 70 ; in other words if a boiler was
made of plates capable of resisting 1001bs. per
square inch, it would be only safe to use 561bs. of
steam in it if single rivetted, and 70Ibs. if double
rivetted.

The new plan of making boilers, as introduced
by Messrs. Alton and Fernie, of the locomotive
department here, is to increase the strength of the
plates at this weak point of all boilers, and instead
of rivetting the plates on the flat part to one
another, to bend the plates to a right angle and
rivet the flanges together, thus angle irons are
entirely dispensed with at the flat ends, and instead
of the joints being the weakest part of the boiler,
they are by far the strongest. They claim as
their invention an entirely new form of boiler plate,
rolled thicker along the edges or sides for a certain
distance and gradually turning into the body of
the plate. These plates they bend and flange, or,
as the case may be, they rivet on flat to the boiler.
In ordinary boilers placed over a fire, or having an
internal flue containing it, the plates next the fire
gradually get thin and have to be replaced. The
locomotive boiler shell is quite removed from the
direct influence' of the fire, but being subjected to
double the pressure of ordinary boilers, and having
to sustain some particular strains consequent
on its being attached to the engine, it waers
differently to an ordinary boiler. Some were
pointed out to us which had a narrow seam or
strip worn out along the inside edge of the joints,
but the greatest amount of wear seemed to be
on those plates that had angle irons attached to
them, and on the opposite side from the angle iron ;
and inside the boiler we saw plates which had a
channel worn out two or three feet long, half an
inch wide, and three-eighths of an inch deep, or
nearly the whole thickness of the plate ; indeed,
some plates we saw were cut clean through, which
had only been at work three years. Now, the new
plates are made sufficiently wide in the thick part
for properly jointing, and also to stand twice the
amount of wear at the joints. So that in the new
boiler, if the plates are strong enough in the body to
resist a 1001 b. per sq. inch pressure, the joints being
made extra thick, are also able to resist the same
or rather more pressure, and consequently an equili.
brium of strength is maintained throughout the
whole boiler. Angle irons, as explained to us, are
Very expensive to keep in repair. When bent and
welded they arc punched, and one side is rivetted
to the boiler shell and the flat ends of the boiler to
the other side of the angle iron, but the fibre of
angle iron runs in the direction of the punched
holes, making them, even when of the strongest- sec-
tions liable to crack from hole to hole. By the new
plan the plate itself is turned over to form the
angle, and the fibre of the iron runs in the right di-
rection, and a whole row of rivets and the consequent
weakening of the plates are thus saved. A very
beautiful adaptation of, the new invention was
pointed out to us in the mannfacture of the
steam domes. These being made from the same
plates allow of the flanges being turned and faced,
and thus good joints are secured. The plates area
capital job, and a credit to the Lowmoor Iron Com-
pany, who are the sole manufacturers of the patent
plates.

We have been thus particularin describing what
we believe to be a first invention; and which, m e
understand, has received the commendations of a
large number of eminent engineers, and we would
recommend our engineering friends to see and exa-
mine the boilers themselves, and would especially
recommend the invention to those about ordering