Improvements in Water Tube Boilers.
Year: 1893

page_text: Date of Application, 28th Dec., 1893
Complete Specification Left, 26th Sept., 1894-Accepted, 27th Oct., 1894
Improvements in Water Tube Boilers.
I, Owen MeREDITII 46 Laird Street Birkenhead in the County of Chester,
Foreman Boiler Maker do hereby declare the nature of this invention to be as
follows:
My invention relates to an improvement in the shape of water tubes of tubulous
boilers, and also to an improvement in the arrangement of the same, where a large
number are placed side by side, and connected to feed and steain pipes by small
bent pipes, or to water space chambers formed of plates retained nearly in a
parallel position by means of numerous screw stays. They are closed at the bottom
and sides, but are opened at their upper portions into a cylindrical steam chest. The
tubes are only connected to one side of the chamber. The water which collects at
the bottom of the vertical steam pipes when they are required, I purpose using to
supply the tubes most exposed to the fire.
The vertical steam and feed pipes will be, between the screwed ends of the
inclined tube and the fire.
The said improvement consists in such tube being bent so that each open end of
the tube can be connected to one vertical plate-the said bent part will be about
one pitch, say from centre to centre of the tubes, wider horizontally, on each side,
than the double tube forming three-fourth's of a ring. If necessary the tubes can
be compressed in certain part or parts, for the purpose of facilitating the bending
and arranging of them in place, and also for screwing their ends. This compression of
the tube-ends will also, if necessary provide room for the vertical feed and steam
pipes.
Each half of the tube has an inclination one upwards and one downwards from
the water chamber off the horizontal line of about one in eight. When the tubes are
straight there will be a clear vertical flame space between each half. At the chamber
ends, two rows of the tubes will be in a line, and the next two rows will be
dropped half a pitch, say from centre to centre vertically, and so on. At the
opposite end, where the bend is about three-fourth's of a ring, the tubes rest one
upon another, nearly in an horizontal position, placed zig-zag.
By my improvements the following advantages are obtained :-
A continuous and almost immediate return of the water is secured, in the tubes most
exposed to the fire, by the constant supply of water in the chamber, or feed and
steam pipes, which will act as circulating pipes. Thus an abundance of water
passing through the tubes is therefore ensured, and all local overheating is therefore
prevented.
My improvement also secures a greater degree of freedom for expansion and
contraction owing to the ring ends of the tubes, being free to move.
Again, as my invention obviates the necessity of screwed joints, bolts, junction
boxes, nipples check-nuts & c. exposed to the fire, the trouble these give, when
overheated, cousequently does not exist.
Dated this 27th day of December 1893.
OWEN MEREDITH.

page_text: Improvements in Water Tube Boilers.
I, OWEN MEREDITH, of 46, Laird Street, Birkenhead, in the County of
Chester, Foreman Boiler Maker, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The improvements which constitute this invention are applicable to water tube
boilers of the type in which steam and water chambers communicate with each
other by intermediate circulating tubes and are provided with heating surface
derived from a large number of water tubes which form a group of connections
between each water chamber and the steam chamber by extending therefrom from
one chamber to the other over a furnace or combustion chamber and the said
improvements relate mainly to the special shape or configuration of the heating
surface water tubes themselves and to their arrangement and distribution taken in
combination with the structural arrangement of the steam and water chambers to
which they are connected.
The water chambers are preferably two in number placed directly below the
steam chamber so that the steam chamber communicates by one or more circulating
tubes with the water chamber next below, which water chamber similarly
communicates with the other water, chamber directly below it.
The beating
surface tubes which are each bifurcated round a ring end or horse shoe bend extend
from the side of the steam chamber preferably below its greatest diameter when taken
transversely in the horizontal direction, in two groups, one group being connected
to the upper water chamber and the other group to the lower water chamber.
By my improvements the following advantages are achieved.
A continuous and quick return of the water from the steam chamber is secured and
a constant supply of water maintained more especially in the tubes most exposed
to the fire and all local overheating is therefore prevented.
My invention also provides a greater degree of freedom for expansion and
contraction of the heating surface tubes owing to their ring ends or horse shoe
bends combined with the freedom of these ends for individual movement and which
tubes are thereby enabled to accommodate the strains due to variation of tempera-
ture instead of transmitting them to the more rigid parts of the apparatus which
are protected from the heat of the furnace. Again as the heat impinges only upon
the heating surface water tubes, my invention obviates the necessity of screwed
joints, bolts, junction boxes, nipples, check nuts and the like being exposed to the
fire and the trouble these accessories give when overheated does not exist.
But inasmuch as the use of the vertical steam and feed pipes referred to in my
Provisional Specification are not essential to the proper working of my invention
and as I have come to the conclusion that the advantage to be derived from them
is more than compensated for by the reduction of parts and greater simplification
of construction to be derived from their absence. I have omitted all further
reference to them in the accompanying drawings and the hereinafter corresponding
description.
In the accompanying drawings forming part of this Specification,
Figure 1 is a transverse sectional view of a boiler embodying my improvements,
and
Figure 2 is a sectional plan view taken ou line of Figure 1.
Figures 3 to 8 inclusive are details illustrating the ring ends or horse shoe bends
for bifurcating the heating surface tubes in the manner required for the purposes
of my invention.
a is the steam chamber communicating by the circulating tubes with the
water chambers cle² placed one above another in the manuer shown, which

page_text: arrangement is to be preferred as affording facilities for increasing the number of
beating surface tubes which are provided in two groups marked collectively did.
The water chambers with their connecting and circulating tubes are
protected from the heat of the furnace or combustion chamber by the screens e¹ e² 8
to promote the circulation of the water through the boiler in the direction indicated
by the arrows.
In order to afford a greater freedom for expansion and contraction in the water
tubes marked collectively d¹², I construct them with the ringed ends or horse
shoe bends as shown in Figures 3 to 8 inclusive, each tube extending from its ring
or bend one leg up to its connection with the steam chamber a and the other leg
down to its connection with one or other of the water chambers ². These ring
ends are supported from the seat, but are detached both from it and from one
another in order to allow for a free expansion or contraction of the tubes. If these
tubes were all bent and bifurcated to precisely the same pattern and relative positions
it is obvious that they would form a kind of vertical enclosure or well, the sides only
of which would be fully exposed to the heat of the furnace. To obviate this and to
expose each tube or tube leg fully to the fire or its escaping hot gases, I vary the
forms of the ring ends, and the distance at which the upper and lower legs of the
tubes are set apart are made to diverge transversely so as to bring about what
would appear in a sectional view takeu on line Z Z as a zig zag arrangement.
instance I place the modifications 1, 3 and 4 above each other in the order in which
these figures are shown above the seat or otherwise vary the several modifications
shown in such other ways as conduce to the same result.
For
In the drawings the heating surface tubes are shown extending from one side
only of the steam and water chambers, viz.:-to the left but they could of course
be provided to extend in precisely the same manner from the opposite side as well
when required that is, to the right, provision being made for diffusing amongst
them the requisite heat whether by providing a second furnace, or by bringing
round to the right hand side and in the reverse direction, the hot gases generated
in the one furnace at the left hand side as shown. But when the heating surface
tubes d'extend from both sides of the steam and water chambers the circulating
tubes are placed centrally in relation thereto as shown in dotted lines, and not
to the off side as shown in full lines and indicating this to be the preferable
arrangement, when the tubes extend from one side only of the said steam and
water chambers a, c¹ and ².
Furthermore although I prefer to construct my improved boiler with two water
chambers c¹ c² as shown and for the reason as already stated, where fewer heating
surface tubes would serve the purpose of my invention, the second water chamber
would be dispensed with.
Having thus fully described my said invention and the way in which it is to be
carried into effect, I wish it to be understood that I am aware that the use of water
tubes connected to a steam chamber at one end and to a water chamber at the
other end and extending therefrom over or into a boiler furnace is not novel, as
this construction of steam boiler is set forth both in the Specification of Letters
Patent granted to John Isaac Thornycroft dated 5th November 1890, Number 17809,
and in the Specification of Letters Patent granted to Peter Ferguson and William
Young Fleming dated 31st December 1892 number 24141. I therefore make no
claim to the use of such tubes as improvements in the construction of boilers or
steam generators, otherwise than as embodied in and carried into practice by my
improvements as bereinbefore described and illustrated, but what I claim is :-
Firstly. In the construction of water tube boilers of the type as hereinbefore
referred to, the use of heating surface water tubes, constructed with ring ends or
horse shoe bends and bifurcated therefrom for the purpose of securing a greater
freedom for expansion and contraction the said tubes being preferably arranged
and grouped for exposure to the heat of the boiler furnace substantially as
herein before described with reference to the accompanying drawings.

page_text: Secondly. The general arrangement and combination of parts constituting a
water tube steam boiler, and embodying the several improvements as and for their
respective purposes as hereinbefore described and illustrated in the accompanying
drawings.
1
C
1
1004
G. J. CLARKSON,
Chartered Patent Agent, Stockton-on-Tees,
Agent for the Applicant.