IMPROVEMENTS IN STEAM BOILERS OR GENERATORS
Year: 1869

page_text: LETTERS PATENT to Andrew Barclay, of Kilmarnock, in the County
of Ayr, North Britain, for the Invention of "IMPROVEMENTS IN
STEAM BOILERS OR GENERATORS."
Sealed the 25th September 1869, and dated the 30th March 1869.
I, ANDREW BARCLAY, of Kilmarnock, in the County of Ayr, North
Britain, do hereby declare the nature of the said Invention for "IMPROVE.
MENTS IN STEAM BOILERS OR GENERATORS," to be as follows, that is to say :-
This Invention relates to certain improvements in that class of steam
boilers for which Letters Patent were granted to Andrew Barclay, dated
the 29th of December 1865, and numbered 3369.

page_text: connected at their lower ends to the water space, and at their upper
ends to an upper chamber. The water space of the boiler proper is
provided with a large number of tubes by means of which additional
heating surface is obtained. From the upper part of the furnace a flue
passes to the top of the chamber, this flue is provided with a damper
which may be opened or closed at will. The outer set of tubes herein-
before mentioned are surrounded with a casing which may be either
single or double, and when double it may be made to constitute an
it is
additional water space or an air space. When used as an air
space
preferred to construct it open at the upper end so that air may be drawn
down through it by the action of the draft in the chimney; the air on
descending becomes heated and is therefore supplied in that state to the
fire. All the air requisite for the combustion of the fuel may in this
manner be supplied, in which case it is necessary to close the opening
below the fire-grate. And when part of the air is taken through the
opening the remainder may be supplied in a heated state from the air
space. Or the space below the fire-bars may be closed and supplied
with air from any blowing apparatus or preferably injected by jets of
steam.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Andrew Barclay in the Great Seal Patent Office
on the 30th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ANDREW
BARCLAY, of Kilmarnock, in the County of Ayr, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of March, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Andrew Barclay, Her special license
that I, the said Andrew Barclay, my executors, administrators, and
assigns, or such others as I, the said Andrew Barclay, my executors;
administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term

page_text: space. Or the space below the fire-bars may be closed and supplied
with air from any blowing apparatus, or preferably injected by jets of
steam.
And in order that my said Invention may be properly understood I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried
into effect, reference being had to the several Figures upon the
explanatory Sheets of Drawings which I have hereunto appended, that
is to say:-
On Sheet 1 Figure 1 is a vertical section of one form of boiler in which
my improvements are shown applied; these improvements consisting
in surrounding the water space A with an annular air or flue space B,
this space B being that in which the additional water tubes C are
contained; the tubes are connected at their upper ends to the water and
steam chamber D. In the chamber D is contained the circular steam
pipe E perforated on its upper side, by which the steam is taken off to
an engine or other mechanism or apparatus where it is to be used. F is
the safety valve. The space below the fire-grate F' is shown closed in
by the casing G, and in this an opening is made to admit the pipe H.
which is connected with a fan or blowing cylinder or other means for
producing a blast of air. The circular ring a, a, of the pipe H is
perforated and through these perforations the compressed air escapes
and mixes with the fuel on the grate F. The pressure of the blast forces
all the waste products of combustion to the upper part of the furnace [,
and the flue K is provided with a damper L which is lifted to the
requisite extent by the pressure of the blast, and the waste products of
combustion are expelled therethrough into the chimney M. In place
however of the boiler being supplied with compressed air, the casing G
and damper L may be dispensed with, in which case atmospheric air is
passed through the boiler by the action of the draught in the usual
manner. The tubes C are covered in by a casing N as shown, this
casing is made double and contains a space between the inner and
outer plates x and y which may be an air space or a water space, and
when used as a water space it is connected directly by tubes or otherwise
to the water spaces of the other parts of the boiler. The casing N may
also be made single, that is without an air space v, and it is preferred to
construct it in segments Q, as shown in the horizontal section Figure 2,

page_text: any one or more of which is or are arranged so as to be removable when
required. O is a handle and system of levers by means of which the
damper L may be raised or lowered as required.
Figure 3, Sheet 1, is a plan of the boiler corresponding to Figure 1,
and Figure 4, Sheet 1, is a front elevation on a reduced scale showing
the fire-door S and the arrangement of the casing N at that part.
At Figure 1, Sheet 2, is shown in vertical section, and at Figure 2,
Sheet 2, in side elevation à boiler similar, except in certain details, to
that shown and herein-before described in reference to the Figures on
Sheet 1 of the Drawings. In this case an engine R is shown attached
for driving the blowing fan T, the rotatory motion of the engine shaft U
being preferably communicated to the fan by the frictional gearing V.
In Figure 1, Sheet 1, as well as Figure 1, Sheet 2, the direction. in
which the heated currents pass from the fuel on the fire-grate Fl.are
indicated by arrows, that is to say, the heat passes from the grate F'
through the tubes f into the outer space B and then to the chimney M,,
excepting that portion of the heat which escapes directly through the
flue K. At Figure 1, Sheet 2, a superheater is shown, it consists of an.
annular chamber X to which the throttle valve chamber 1 and safety
valve 2 are connected; this superheater is connected to the steam space
of the boiler by steam pipes Y, and the heat in the smoke box acts upon
the chamber X and superheats the steam therein.
On Sheet 3 two boilers arranged in accordance with my present.
improvements are shown the essential difference in these examples from
those shown on the two preceding Sheets of Drawings being, that
whereas in the former examples the boilers are circular in section in
those shown at Sheet 3 they are rectangular or oblong in section.
Figure 1 is a longitudinal section; Figure 2 a section transverse, or at
right angles to Figure 1, and Figure 3 a horizontal section on the
line a, a, Figures 1 and 2. The direction in which the heated currents
or gases pass from the fuel is indicated by the arrows.
The arrangement of the casing in the neighbourhood of the fire-door
as well as the fire-door itself is shown at Figure 4.
Figures 5, 6, and 7 are views corresponding to Figures 1, 2, and 3 on
the same Sheet of Drawings, but in this latter example an additional
row of tubes marked a is employed. In place of making the upper

page_text: part, chamber, or steam and water space of the boilers of larger diameter
than the lower part or water space it may when requisite be made of
the same diameter as the lower part, in which case all the tubes con-
nected thereto will be fixed by a joint of the kind shown at e, Figures
5 and 6, Sheet 3.
:..
On Sheet 4 at Figure 1 is shown in longitudinal section, and at
Figure 2 in horizontal section on the line a, a, Figure 1, a boiler con-
structed in accordance with the Specification of the Letters Patent on
which the present improvements are based, namely, No. 3369, 1865,
herein-before referred to, and the improvements now shown, although
constituting no feature of the invention claimed under this present
Specification, may be applied to the boilers set forth in the Speci-
fication herein-before referred to, as well as to those shown on the
other Sheets of Drawings hereunto appended, but in the example now
referred to a greater number of water tubes e in the interior of the fire-
box or furnace A are employed. In the outer space B the water tubes
connecting the water space above the tube plate C with the water
space D are not shown, but they may be employed or omitted as
desired.
At Figure 3 is shown in section another boiler differing in form from
the preceding, that is to say, the upper chamber X is not enlarged as in
other examples, but made of the same diameter as the lower part of the
boiler Y. Tubes in the outer space B are not shown in this example,
but they may be adopted or dispensed with as desired.
In order to place as many tubes as possible in the furnace or fire-box
is is preferred to make the top tube plate into the form of a hollow cone,
as shown in section at A, Figures 4 and 5, and in horizontal section on
the line b, b, Figures 4 and 5, at Figures 6 and 7. By this arrangement
of the tube plate a greater surface is obtained for receiving the tubes,
and consequently a greater number of tubes may be inserted than when
a flat tube plate is employed, as in the other examples shown in the
preceding Sheets of Drawings. At Figures 5 and 7 the central part o
which is left vacant in Figures 4 and 6 is filled in with a circular water
space or enlarged tube P, this is connected to the upper part of the
boiler by the branch tubes Q and Q', Q', being made to descend to
nearly the bottom of the tube or space P so as to facilitate the circulation
of the water, and the tube or space P is further connected to the lower

page_text: part of the boiler by the branch R, which couples it to one of the
tubes A. In lieu of fixing the upper ends of the tubes A to a flat tube
plate, as shown in the former modifications, or to a conical tube plate
as in Figures 4, 5, 6, and 7, the upper ends may be fixed into the
upper part of the inner side plates 1 of the boiler in a manner similar
to that in which their lower ends are connected to the boiler.
Figures 8 and 9 respectively are plans of two forms of the perforated
pipes or tubes through which the compressed air is forced below the
fire-grate of the boilers when these are worked by pressure instead of by
draught as herein-before set forth.
It is further to be understood that my improvements are applicable to
forms of boilers other than those which I have herein-before described
and shown in the annexed Drawings.
Having now described the nature of my said Invention, and the
manner in or under which the same is or may be carried out in practice,
I would observe in conclusion that what I consider novel and original,
and therefore claim as the Invention secured to me by the herein-before
in part recited Letters Patent is,―
First. The addition to steam boilers of water tubes outside the water
space of the boiler proper and surrounded by a casing, substantially as
herein-before described and shown on the annexed Sheet of Drawings.
Second. The closing in of the lower parts of steam boilers and the
maintaining of the combustion of fuel therein by means of compressed
air, which also expels the noxious and waste products of combustion by
lifting a valve or damper on or in the flue or chimney.
In witness whereof, I, the said Andrew Barclay, have hereunto
set my hand and seal, this Twenty-eighth day of September,
Eighteen hundred and sixty-nine.
Witness,
ST. JOHN VINCENT DAY, C.E.,
Glasgow.
ANDREW BARCLAY. (L.S.)