Improvements in Tubular Steam Boilers.
Year: 1887

page_text: Date of Application, 15th Aug., 1887
Complete Left, 10th Mar., 1888
Complete Accepted, 13th Apr., 1888
PROVISIONAL SPECIFICATION.
Improvements in Tubular Steam Boilers.
We ROBERT MUDGEMARCHANT, of 25 Canonbury Villas, Islington, in the County of
Middlesex, Civil Engineer, and JAMES RICHARD BRUSHETT, of 20 High Holborn,
London, in the County of Middlesex, Gentleman, do hereby declare the nature of this
invention to be as follows:-
Our invention consists in the combination of water tubes with interior flame tubes,
in connection at one end with a boiler compartment to be seated immediately over the
furnace thereof and at the other end with another boiler compartment which forms
the top of the boiler proper and contains the steam chamber thereof.
In such combination the water tubes assist to stay the interior plates of such upper
and lower boiler compartments and they terminate at their point of connection with
these, whilst the flame tubes pass through and beyond these water tubes and at each
end through the compartments and are attached to the outer plates of each compart-
ment so as to assist to stay these outer plates.
These boiler compartments are further stayed by short flame tubes attached to the
top and bottom plate of each compartment and in such manner that as regards the
lower compartment these shorter flame tubes pass a portion of the products of com-
bustion from the furnace through such compartment and into the combustion chamber
between the two compartments. In this combustion chamber the heat acts on the
surface of the water tubes and is communicated through it to the water within the
annular spaces existing between such water tubes and its interior flame tubes,-such
water being therefore acted on both from the surface of the interior flame tubes and
from the surface of the exterior water tubes.
The short flame tubes in the upper boiler compartment connect in the same way
through it, from the combustion chamber (between the compartiments) with the smoke
box and chimney beyond it over such compartment, into which so much of the
products of combustion as passes through the continuous and interior flame tubes
(within the water tubes) has direct access. In such manner a maximum of heating
surface can be obtained.
We provide rapid and efficient circulation in the boiler by omitting the interior
flame tube to the central water tube and by using in place thereof a tie rod of

page_text: wrought iron or steel between the external plates of the boiler compartments. We
make such tie rod of as much less than half the diameter of the flame tubes as the
staying power for the pressure used renders desirable. By this provision the central
water tube is rendered full of water which is exposed to less heating surface, and
owing to its consequently lower temperature this water tube constitutes the down
passage for the water circulation whilst all the other water tubes in their annular spaces
owing to their higher temperature constitute the up passages of communication.
For the construction of large boilers any number of sections constructed as above
described can be employed the diameter of each section being preferably from four to
six feet. Such sections would be connected by means of a top and bottom external
tube with a branch connection from these to the top and bottom of each section and
by placing a cock in each branch connection any one of the sections can at any time
be isolated from the other sections and boiler and for any purpose and any other
provisions for such eventuality or requirement can be of any ordinary or evident
character.
J. C. MEWBURN,
169, Fleet Street, London,
Agent.
We ROBERT MUDGEMAROHANT, of 25 Canonbury Villas, Islington, in the County of
Middlesex, Civil Engineer, and JAMES RICHARD BRUSHETT, of 20 High Holborn,
London, in the County of Middlesex, Gentleman, 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
:-
Our invention consists of a combination in which water tubes with interior flame
tubes are in connection at one end with a boiler compartment seated immediately over
the furnace thereof and at the other end with another boiler compartment which forms
the top of the boiler proper including the steam chamber thereof. In such com-
bination the water tubes assist to stay the inner plates of the upper and lower boiler
compartments and they terminate at their point of connection with these, whilst the
flame tubes pass through and beyond these water tubes and through the compart-
ments and are attached to the outer plates of each compartment so as to assist to stay
these outer plates.

page_text: These boiler compartments are further stayed by short flame tubes attached to the
top and bottom plate of each compartment and in such manner that as regards the
lower compartment these shorter flame tubes pass a portion of the products of com-
bustion from the furnace through such compartment and into the combustion chamber
between the two compartments. In this combustion chamber the heat acts on the
surface of the water tubes and is communicated through it to the water within the
annular spaces between such water tubes and the interior flame tubes, such water
being therefore acted on both from the surface of the interior flame tubes and from
the surface of the exterior water tubes.
The short flame tubes in the upper boilor compartment connect in the same way
through it, from the combustion chamber (between the compartments) with the smoke
box and chimney beyond it over such compartment, into which so much of the products
of combustion as passes through the continuous and interior flame tubes (within the
water tubes) has direct access. In such manner a maximum of heating surface can
be obtained.
We provide rapid and efficient circulation in the boiler by omitting the interior
flame tube to the central water tube and we use in place thereof a tie rod of wrought
iron or steel between the external plates of the boiler compartments. We make such
tie rod of as much less than half the diameter of the flame tubes as the staying power
for the pressure used renders desirable. By this provision, that is to say, by the
omission of the interior flame tube the central water tube is maintained full of water
which is exposed to less heating surface, and owing to its consequently lower tem-
perature this water tube constitutes the down passage for the water circulation whilst
all the other water tubes in their annular spaces owing to their higher temperature
constitute the up passages of communication.
For the construction of large boilers any number of sections constructed as above
described can be employed the diameter of each section being preferably from 4 to
6 feet. Such sections would be connected by means of a top and bottom external
tube with a branch connection from these to the top and bottom of each section and
by placing a cock in each branch connection any one of the sections can at any time
be isolated from the other sections and boiler and for any purpose and any other
provisions for such eventuality or requirement can be of any ordinary or evident
character.
The annexed drawings will serve to illustrate the invention:-Figure 1 is an
elevation of one of our improved tubular boilers of circular form. The case is
preferably of double plate iron filled between the plates with slag cotton or other non-
conducting material. Figure 2 is a vertical section through the centre of the case and
of the contained boiler shewing the boiler compartments and the combustion chamber
between them, through which the connecting water and flame tubes pass as shewn.
The short stay flame tubes to the compartiments are also shewn, those to the lower com-
partments acting as flame tubes from the furnace to the combustion chamber and those
to the upper compartment delivering the products of combustion into the smoke box.
This figure also shews the central water tube which, owing to its reduced heating
surface and consequently lower temperature, due to the omission of an interior flame
tube, constitutes a down passage for the regular circulation of the boiler water. Figure 3
is a horizontal section through the boiler at the level A, B (Figure 2); Figure 4 is a
plan of the top of the boiler; Figure 5 is a detail section shewing the attachment of
the water and flame tubes to the boiler compartments; Figure 6 shews a flame tube
passing through the upper boiler compartment above the termination of the water
tube; Figure 7 shews a side view of a larger construction arranged for the building
up in sections of a boiler of any required power. Any required number of such
sections can be made to constitute one boiler, a top and bottom pipe connection being
provided to all the sections with stop cocks so placed for use that any section can be
isolated. Figure 8 is a plan of two such sections in connection. Similar letters of
reference in the several figures indicate corresponding parts.
a, a represent the boiler casing. b, are the clearance doors to the combustion
chamber and smoke box respectively. c, c are the annular spaces between the internal

page_text: flame tubes and the water tubes. d is the tie bar which is substituted for the flame
tube in the central water tube which serves as the down passage for circulating
purposes. e, e are the flame tubes which pass through the water tubes. f,f are the
short flame tubes leading through the lower boiler compartment to the combustion
chamber and f¹, f'the short flame tubes leading through the upper boiler compartment
to the smoke box. 9, y are the boiler compartiments. is the combustion chamber. i the
furnace. the steam pipe. k, k the water tubes. the smoke box. m, m (Figures 7
and 8) pipes connecting sections. n, n stop cocks to isolate the sections from the
boiler when desired. p, p, Figures 2 and 6, are angle irons by means of which the
boiler compartments 9, 9 can be built up and strengthened; the number of these
angle irons will depend upon the depth of the compartments.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim, in respect of tubular boilers, is :-
1. The combination with two boiler compartments,. the one of which is seated
immediately over the fire and the other of which forms the top of the boiler proper
including the steam chamber, of water tubes connecting said boiler compartments and
forming stays to their inner plates and of flame tubes passing through said water
tubes and through said compartments and forming stays to their outer plates,
substantially as herein before described and shown in the annexed drawings.
2. The combination with two boiler compartments and with water tubes and flame
tubes as referred to in claim 1 of short flame tubes attached to the top and bottom
plates of each boiler compartment, substantially as herein before described and shown
in the annexed drawings.
3. The combination of a furnace, combustion chamber, smoke box, upper and lower
boiler compartments, water tubes internal flame tubes, short flame tubes connecting
the furnace with the combustion chamber and short flame tubes connecting the com-
bustion chamber with the smoke box, whereby the water in the water tubes is exposed
to heat both outside of and within said tubes, substantially as hereinbefore described
and shown in the annexed drawings.
4. In a combination such as that referred to in claim 1, we claim the fitting of one
or more of the water tubes without internal flame tubes whereby owing to the reduced
heating surface of such tube or tubes and their consequently lower temperature they
constitute down passages and ensure a regular and sufficient circulation of the water,
substantially as hereinbefore described and shown in the annexed drawings.
5. In the construction of large boilers, the combination of two or more sections
constructed as herein set forth these sections being connected by means of top and
bottom tubes or pipes provided with means whereby any one section can be isolated
when required, substantially as herein before described and shown in the annexed
drawings.