IMPROVEMENTS IN STEAM BOILERS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by John Jones at the Office of the
Commissioners of Patents, with his Petition, on the 25th November
1878.
I, JOHN JONES, of Chesnut House, Stratford, in the County of Essex,
3 do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
STEAM BOILERS," to be as follows:-
This Invention relates to the construction and arrangement of parts of
steam-boilers--with a view to obtain a large amount of effective heating
surface, and to give facilities for cleansing and repair. For this purpose
the external part of the boiler is made to consist of a vessel of such length
as may be desired, and having its transverse section of horse-shoe form
like an inverted U with the circular part forming a top chamber for
water and steam space, and the two limbs serving as water ways and
forming the sides of the furnace or fire-box. These two limbs are con-
nected near the bottom by a pipe of considerable size so that the feed
water supplied to either limb may readily flow into the other, and this
pipe may form part of the bridge of the furnace. A cylindrical vessel
containing longitudinal tubes is suspended within the U shaped fire-box

page_text: by pipes (preferably tapering to a larger diameter upwards) through
which the water circulates. At the back of the fire a bridge is carried
up some height and made to fit the lower part of this cylindrical vessel,
so that the flames and hot products of combustion rise round the vessel
and act upon its circumference; they then pass over the bridge into a
flue chamber behind the back end of the cylindrical vessel, whence they
pass through the tubes of the vessel to the front part of the boiler and
up a chimney or up-take with which the tubes communicate.
By this arrangement and construction the surface on which the fire
acts is made of considerable extent, consisting of the interior of the fire-
box, the exterior periphery of the cylindrical vessel and its suspending
pipes, and the interior surface of the tubes in the vessel. As the vessel
hangs from the upper part of the boiler, and is not otherwise connected
to it, the slight changes of its position occasioned by expansion or
contraction throw no strain on it or the boiler tending to break joints.
By placing the boiler on a bed a little sloped so that the one end of
its water space and of the cylindrical tube vessel is somewhat lower in
level than the other end, the water will freely circulate down the
suspending pipe at the lower end, and up the suspending pipe at the
higher end, and bubbles of steam formed within the vessel will be
carried rapidly up into the steam space in the upper bend of the U.
In case of the cylindrical vessel or its tubes requiring cleansing or
repair, the joints by which it is attached to the suspending pipes or by
which these are attached to the upper part of the fire-box can be undone
and the cylindrical vessel can be taken bodily out of the boiler to be
repaired and replaced, or to have its place occupied by a spare vessel.
When the boiler is large several cylindrical vessels may be suspended
parallel to one another in the fire-box, so that the flame and hot
products of combustion can act on the extended surface afforded by
their several peripheries, and any one of them when out of repair can be :
removed and replaced by a spare one.
The limbs of the inverted U shaped vessel instead of being made like
the ordinary water ways of boilers may consist of tubes arranged either
vertically so as to communicate from a water chamber below to the
water and steam space above, or horizontally communicating with a
vertical pipe or chamber at either end, or with each other at their
opposite ends alternately. Such tubes may be jointed to each other or

page_text: to the chambers with which they communicate either by flanges or by
screwed nipples secured by internal nuts.
The cylindrical tube vessel with its ends may be rivetted up like the
barrel of a locomotive or other tubular boiler, or it may be welded, or the
tube plates forming its ends may be jointed to flanges formed on the
cylindrical casing, the flange at one end being interior and that at the
other end exterior, so that the tubes and their plates can be removed to
give access for cleaning or repair.
Instead of employing flanges for these joints a water-tight junction of
the tube plates to the cylindrical casing may be formed by glands and
packing. For this purpose the tube plate may be flanged inwards to a
diameter less than that of the casing so as to afford an annular space for
packing, and may have on its flange an inner projecting rim to retain
the packing in this annular cavity. The gland which compresses the
packing may be secured by bolts hooking over a projecting ring on the
external cylindrical casing.
The water ways and body of a boiler constructed as above described
may be strengthened by stays in the usual way, and the crown of the
fire-box may be stiffened by girders forming an open cellular structure
in the manner frequently employed for the fire-boxes of locomotives.
Also the sides of the fire-box and the lower side of the cylindrical vessel
may be protected from the direct action of the fire by linings of fire-
brick. The back of the flue chamber and front of the up-take may be
made moveable so as to give access to either or both ends of the tubes
in the cylindrical vessels. ·