An Improvement in Self-contained Water-tube Boilers.
Year: 1894

page_text: Date of Application (in United Kingdom), 30th Jan., 1894
Complete Specification Left, 30th Jan., 1894-Accepted, 18th Aug., 1894
An Improvement in Self-contained Water-tube Boilers.
I MONTAGUE HERBERT CHURCHILL THANN of 173 Wicklam Terrace
Brisbane in the Colony of Queensland, Australia Engineer 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 :-
My invention relates to improvements in water-tube boilers, and has for its
object an arrangement whereby they may be self-contained-that is to say the
usual brick-work surrounding the furnace and stack of tubes may be dispensed
with, and the hot gases passing among the tubes may be retained by a water-jacket
on either side.
My invention consists of rows of parallel inclined tubes, arranged over the fire
in a special manner to be hereinafter described; and a special arrangement of the
front connections to be hereinafter described; and any convenient means of con-
necting the rear ends of the tubes; and a steam drum attached to the front
connections, with a water-jacket on either side of the said tubes-said water-jackets
extend lengthwise between the front and back connections, and in height extend
from the fire bars to above the top of the tubes, or thereabouts.
Each said water-jacket is connected to the front connections by two pipes or any
similar convenient means, one at the top and the other at the bottom, so as to
provide for the exit of steam and inflow of water respectively. Each of said
water-jackets is constructed of two flat plates, stayed together, forming its inner
and outer sides; the top and bottom and two ends may be formed by flanging the
plates themselves, and rivetting the flanges, or by any other convenient means--
the whole forming a flat box of approximately rectangular shape.
The whole of aforesaid parts I brace together by suitable framework. The back
connection is fastened to the rear end of each of the water-jackets by means of
curved flat bars, and the rear ends of the water-jackets are supported by similar
flat curved bars attached to the frame work.
The top of the stack of tubes between the water-jackets on either side, and
between the front and back connections at either end, I cover over with a suitable
casing of sheet iron, or other suitable material.
I lead the exit flue from the top of said casing.
Between each end of each water-jacket and the front and back connections, I
leave a small space, which I encase with plate-work, and in said plate-work I provide
a series of small holes with a door to each; said holes are opposite the opening
between each of the horizontal rows of tubes.
The object of which holes is to enable a steel or other brush to be inserted
between each of the horizontal rows of tubes from each corner of the tube stack
for the purpose of cleaning the exterior of the tubes.

page_text: The ash pit I form of flat-work, supported from the front and back connections,
and from the water-jackets; said ash pit is provided with a damper door and rack
in the usual manner.
The special arrangement of tubes herein before alluded to consists in terminating
the upper and lower rows of tubes in separate vessels or chambers at their front or
higher ends that is to say, the upper rows of tubes at their front ends are
terminated in one vessel, or set of vessels, and the lower rows at their front ends
are terminated in another vessel, or set of vessels.
The special arrangement of the front connections may be effected in three
different ways.
The first way consists of a vertically inclined diaphragm plate, fixed centrally
between the front and back plates, to form two chambers; between the top of said
diaphragm plate and the crown of the two chambers a passage is provided so as
the steam may pass from said chambers to the steam drum, the upper rows of
tubes terminating at the said back plate, and the lower rows of tubes with the
diaphragm plate, which terminations are effected by making the upper rows of
tubes shorter than the lower rows.
The front plate of the front connection has formed therein the same number of
holes as there are water-tubes, and each hole is provided with a cover to permit of
the inspection of, or repairs to, the tubes; the holes aforesaid correspond with the
holes provided in the upper part of the diaphragm plate for the circulation of the
water from one of said chambers to the other chamber, and also for the inspection
of the upper rows of tubes.
The second way consists of:-A diaphragin plate. is fixed horizontally, and
inclined to form two chambers one above the other.
There are two circulating pipes, termed side pipes, connected with the sides of
the lower chamber and the upper portion of the sides of the upper chamber above
the water level.
Hand-holes and covers are provided similar to those described in the first
style.
The third way consists of:-The arrangement of the upper rows of tubes to
communicate with the upper portion of one or more water chamber or chambers,
and the lower rows of tubes with the lower portion of one or more other chamber
or chambers, all of which chambers are separately arranged, and form the front of
the boiler.
Hand-holes and covers are provided similar to those described in the first
style.
The object of these special arrangements of the tubes and their front con-
nections in combination with the aforesaid water-jackets, is that the special
arrangements promote such a rapid circulation down the upper rows and up the
lower rows that a very high rate of evaporation per square foot of heating surface
on the tubes is obtained; consequently a much smaller number of shorter tubes
are required than is usual with boilers of this type for the same power, so that the
water-jackets are kept within reasonable limits as to size and weight, which hitherto
has been the great objection to the employment of this simple means of water-
jacketing the furnace and stack of tubes.
In order that my said invention may be better understood, I now refer to the
accompanying sheets of drawings in which the same letters indicate corresponding
parts in all the figures.
Figure 1 is a sectional elevation.
Figure 2 is a plan view.
Figure 3 is an outside elevation.
(AA) and (B B) are the upper and lower rows of tubes respectively.
(C) and (D) are the two front connections.
(E) is the back connection; (F) is the steam drum; (H H) are the two water-
jackets; (II) are the two top pipes connecting (HH) to (C), (D): (J J) are
the two bottom pipes connecting (H H) to (C), (D); (K) is the framework;

page_text: (LL) are the flat curved bars connecting (HH) to (E) and to (K); (M M) are
the spaces between (H) and (C), (D), and (E); (N) is the plate-work encasing (M);
(00) are the series of holes or soot-cleaning doors in (N).
Figs. 4, 5, 6, 7 are various methods of the first style, and show different ways of
arranging the vertically inclined diaphragm plate (P) separating (C) and (D);
(Q) is the passage on top of (P) leading to (F); (RR) are the hand-holes and
covers in front of (D); $ S are the holes in (P).
Fig. 8 is a sectional elevation showing the second method of forming (C)
and (D).
Figure 9 is a front view of same. In this case (C) lies on top of (D), and (P)
is horizontally inclined, and has no holes in it.
(TT) are the two side pipes.
(RR) are the hand holes and covers in front of (C) and (D).
Fig. 10 is a sectional elevation showing the third style of forming (C) and (D),
and Fig. 11 is a front view of same.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is
First In water-tube boilers having the upper and lower rows of parallel inclined
tubes, terminating respectively at their upper ends in two chambers, and a vertically
inclined diaphragm plate, separating said chambers and holes in said diaphragm
plate opposite the tubes in the said upper rows, combined with water-jackets
substantially as herein before described, and as illustrated in my drawings.
Second In water-tube boilers having the upper and lower rows of parallel
inclined tubes terminating respectively at their upper ends in two chambers, and a
horizontally inclined diaphragm plate separating said chambers, combined with
water-jackets substantially as hereinbefore described, and as illustrated in my
drawing.
Third In water-tube boilers having the upper and lower rows of parallel
inclined tubes terminating respectively at their upper ends in two chambers, lying
side by side, combined with water-jackets substantially as hereinbefore described,
and as illustrated in my drawings.
Fourth In water-tube boilers having a stack of tubes and water-jackets, and
front and back connections, combined with flat curved bars, substantially as herein-
before described and illustrated in my drawings.
Fifth In water-tube boilers having front and back connections, and water-
jackets, combined with sets of soot-cleaning doors, substantially as hereinbefore
described and as illustrated in my drawings.
Dated this 26th day of December 1893.
MONTAGUE H. C. THANN.
W. P. Thompson & Boult,
Agents for the Applicant.