IMPROVEMENTS IN TUBULAR STEAM BOILERS
Year: 1884

page_text: I ROBERT MUDGE MARCHANT of 69 Fenchurch Street in the City of London
Civil Engineer do hereby declare the nature of my invention for IMPROVEMENTS
IN TUBULAR STEAM BOILERS to be as follows:-
My invention relates to tubular steam boilers and chiefly consists in fitting a
flame tube within each of a series of water tubes, the flames or products of
combustion or the bulk thereof passing through these flame tubes so that the water
tubes are as it were between two fires viz; the fire in the flame tubes and the
furnace heat acting upon the exterior of the water tubes.
In carrying out my invention I prefer to make the flame tubes of an external
diameter about an inch less than the internal diameter of the water tube so that
there shall be a concentric water space of half an inch between them. I connect
the ends of the water tubes in any suitable manner to the inner plates of two
boiler compartments, there being one such compartment at each end of the tubes;
these compartments constitute the boiler proper. The flame tubes pass beyond the
inner plates of the boiler compartments to the outer plates of the same to which
they are connected; they thus act as stays to the outer plates while the water
tubes act as stays to the inner plates of the said compartments-Where these
compartments are not stayed by the water and flame tubes they can be stayed in
any suitable way; the distance between the outer and inner plates of the
compartments may be from 5 inches upwards according to the water capacity
required. External to the boiler compartments are ordinary arrangements for
providing for the circulation of the flames and products of combustion; these pass
from the back of the flame chamber through the lower set of flame tubes to &
smoke box at front and then back through a higher set of flame tubes and thence
either to the flue and chimney or through a third set of flame tubes and thence to
the flue and chimney.
The upper parts of the two boiler compartments form steam spaces or chambers
and these are connected together by a pipe or pipes from the centre or other
convenient part of which the steam is taken off to the engine cylinders.
In combination with the flame and water tubes and boiler compartments before
described I sometimes and preferably construct the boiler with a set of water tubes
37

page_text: surrounding the flame chamber and as it were forming the furnace; these tubes are
connected at their ends to the boiler compartments and thus constitute part of the
boiler space.
I cover the top and sides of the boiler with a non-conducting shield. composed
by preference of a jacket filled with any suitable non-conducting material so that
the furnace heat is retained within the shield and acts upon the outside of the
water tubes.
The water tubes should all be made of one length for convenience of construction
and renewal; the same remark applies to the flame tubes.

page_text: I ROBERT MUDGE MARCHANT of 69 Fenchurch Street, in the City of London,
Civil Engineer, do hereby declare the nature of my invention for "IMPROVEMENTS
IN TUBULAR STEAM BOILERS" 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 tubular steam boilers in which a flame tube is fitted
within each of a series of water tubes the flames or products of combustion or the
bulk thereof passing through the flame tubes so that the water tubes are as it were
between two fires, viz: the fire in the flame tubes and the furnace heat acting upon
the exterior of the water tubes.
The improvements consist in connecting the ends of the water tubes in any
suitable manner to the inner plates of two boiler compartments which are situated.
respectively at the two ends of the tubes and constitute the boiler proper while the
flame tubes pass beyond the inner plates of the said boiler compartments to the
outer plates of the same to which they are connected; the flame tubes thus act as
stays to the outer plates while the water tubes act as stays to the inner plates of
the said compartments.
The improvements further consist in the combination with the flame and water
tubes and boiler compartments of a set of water tubes forming the bottom of the
furnace and serving to support the fire bars; these tubes are connected at their
ends to the boiler compartments and thus constitute part of the boiler space.
Figure 1 of the accompanying drawings is a front elevation with the smoke box
removed and Figure 2 a transverse section of a tubular steam boiler constructed
according to my invention, Figure 3 represents on a larger scale the preferred
mode of connecting the front ends of the water and flame tubes to the inner and
outer plates of the front boiler compartment and Figure 4 the preferred mode
of connecting the rear ends of the said tubes to the plates of the rear boiler
compartment.
a, a are the two boiler compartments hereinbefore referred to. b, b are the water
tubes;
their ends are connected to the inner plates of the compartments a, a in
the manner shown or in any other suitable way. c, c are the flame tubes; they
are passed through the water tubes b, b and connected at their ends in the manner
shown or in any other suitable way to the outer plates of the compartments a, a;
the tubes c, c thus act as stays to the outer plates while the tubes b, b act as stays
to the inner plates. Where the compartments are not stayed by the water and
flame tubes they can be stayed by the stays shown at e, e or in other convenient
way. The distance between the outer and inner plates of the compartments a, a
may be from 5 inches upwards according to the water capacity required. The
external diameter of the flame tubes is preferred to be about an inch to an inch
and a half less than the internal diameter of the water tubes so that there shall be
an annular water space of from one half to three quarters of an inch between them.
External to the boiler compartments a, a are the arrangements for providing for
the circulation of the flames and products of combustion; the bulk of these enter
the flame or combustion chamber fat the back of the boiler and pass therefrom
through the lower set of flame tubes to a smoke box g at the front of the boiler
while the remainder of the products pass through an opening in a horizontal boiler
compartment h immediately over the furnace into the water tube chamber from the
top of which and by a tube i containing a damper for regulating the draught in
that direction this portion of the products descends to the bottom of the smoke
box
I where it mixes with the products which have passed through the lower set

page_text: of flame tubes. From the smoke box g the whole of the products of combustion
pass through the upper set of flame tubes to the flue k and chimney. The upper
parts of the boiler compartments a, a form steam spaces or chambers, the dotted
line representing the normal water level, and these upper parts are connected
together by horizontal compartments m, m (of which there may be one or more)
and from the centre of the upper compartment or other convenient part the steam
is taken off to the engine cylinders. n, n are the set of water tubes herein before
described which form the bottom of the furnace and support the fire-bars; they
áre connected at their ends to the compartments a, a.
The lower of the two
boiler compartments m, m covers the top of the water tube chamber. The sides of
the boiler are covered by non-conducting doors p, p constructed by preference of an
outer skin or jacket of iron lined with fire bricks which are secured to the doors
by irons or otherwise so that the furnace heat is retained within the chamber
and acts upon the outside of the water-tubes. The water tubes should all be made.
and shouldered to one exact length for convenience of construction; the same
remark applies to the flame tubes and these should be so fitted, as in the manner
shown for example, that they can be readily removed and renewed!
J
o is a water shield forming the back of the flame or combustion chamber f and
communicating with the back compartment a. The sides of the chamber fare
closed or formed by doors lined with fire brick. Easy access to the flame tubes can
be got by the doors of the smoke box g.
The boiler should be set forwards to an incline of about 1 in 12 so as by its
forward cant to create to create a flow of water to the hottest part.
The metal of the vertical and horizontal boiler compartments and of the water
tubes constitutes the skin of the boiler and from their construction and character
these are capable of resisting steam pressures for which the skin of any ordinary
cylindrical boiler is incapacitated by its comparatively excessive diameter and by
the impracticability of staying the outer skin to any similar extent to that shown
for the compartments in my boiler.
I make no claim per se to the employment of flame tubes within water tubes in
tubular steam boilers.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. Constructing tubular steam boilers with water tubes having internal flame
tubes, the water tubes being connected at their ends to the inner plates of boiler
compartments and the flame tubes being connected at their ends to the outer plates
of the said boiler compartments so that the said water tubes and flame tubes
respectively act as stays to the inner and outer plates substantially as hereinbefore
described.
2. The combination with the said water tubes, flame tubes and boiler com-
partments of a set of water tubes forming the bottom of the furnace and
connected with the said boiler compartments, substantially as herein before
described.
3. Constructing tubular steam boilers as hereinbefore described.

page_text: 0 0 0 0 0 0 0 0 0 0 0 0 0 00000000
00
00000000000
4
O O
O O
0000
000
@ O
O O O
Ο
Ο
0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
M1.
m
O O O O O O O O O O O O 0000
0000000000000