IMPROVEMENTS IN STEAM-BOILERS
Year: 1882

page_text: LETTERS PATENT to George Gatton Melhuish Hardingham of 191 Fleet
Street, in the County of Middlesex, Civil Engineer, for an Invention of
"IMPROVEMENTS IN STEAM-BOILERS"
PROVISIONAL SPECIFICATION left by the said George Gatton Melhuish
Hardingham at the Office of the Commissioners of Patents on the 18th October
1882.
GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the County
of Middlesex, Civil Engineer, "IMPROVEMENTS IN STEAM BOILERS"
My Invention relates to the class of steam boilers.commonly called "Sectional; "
that is to say, boilers whereof the major portions are composed of a number of
units of similar construction arranged and connected to work in unison; each of
these units or sections being of a convenient size and weight for manufacture,
handling, transport, erection &c., as also for dismounting, repair or substitution
when necessary.
With a view to increasing the heating surface in boilers of this description,
more effectively absorbing the heat generated by the fuel under combustion and
by these means securing cheapness and compactness of construction together with
speed and economy in working, I adopt in place of the ordinary water tube (such
for instance as that employed in the boiler known as "Roots"), a compound
water and fire tube; that is to say, a water tube exposed externally to the fire but
itself containing a fire tube or tubes. In a compound tube of this character the
water is disposed in a comparatively thin layer, both sides of which are in contact
with the heating surface.
Each section of my improved boiler consists of a tube furnished at each end
with a hollow box and containing an internal tube of considerably smaller
diameter. The hollow boxes may be screwed to the external tube; or may be
formed with recesses for receiving its ends, such recesses being packed with
caoutchouc or asbestos rings or washers or otherwise. The internal tube extends
through both end-boxes and is provided at each extremity with a screw-ferrule,
[Price 6d 1

page_text: nut, collar or other fastening, adjustable or otherwise, for securing the said
internal tube to the end-boxes and the latter to the external tube when not
independently screwed or fastened thereto. The screw-ferrule or nut also nets, by
preference in conjunction with a caoutchouc or asbestos ring or washer or other
soft or elastic packing, to render the extremities of the internal tube steam tight
in the end-boxes. Each terminal box is further provided with an opening at both
top and bottom; by means of which water or steam communication is established
between such box and the two adjacent boxes, respectively above and below. The
parts described, when arranged and fitted together in the manner above indicated,
constitute a section of my improved sectional boiler.
Several of these sections are intended to be placed one above another to form a
tier, and several of such tiers may be placed side by side; the terminal boxes of
one tier being laterally in contact with or close to those of the adjoining tier.
For socuring a tier of sections together when so arranged, I pass between each
two tiers of laterally contiguous sections (and outside in the case of an external
tier) a bolt or bar, to which a nut, cotter or other adjustable fastening is subsequently
applied. Such bolts or bars are introduced at both ends of the tiers, and may be
conveniently arranged in recesses formed in the sides of the terminal boxes. On
tightening these several fastenings, the top and bottom faces of the terminal boxes
of the respective tiers are drawn together and the sections themselves secured in a
vertical or other direction in which the tier is formed. Between the faces just
referred to, sheets or washers of asbestos-millboard or other suitable packing may
he introduced to assist in rendering the joints steam-tight.
In addition to the means already described for connecting together the several
sections in each tier, the ends of the tiers themselves may with advantage be
connected transversely both at top and bottom with a view to steadying them in
position, and, in some cases with the further object of opening communication
between the feed inlet and the several tiers and between these and the steam
outlet.
According to another improved method of constructing and arranging compound
water and fire tube sections of sectional boilers; I substitute for the external
cylindrical tube, referred to in the foregoing description, an elliptical or flattened
tube; it being well known that the area of an ellipse or of a circle when flattened
is smaller than that of a true circle of equal circumference. In other words, for a
given volume or weight of water in the tubes, I obtain, by using external tubes of
this form, a relatively larger heating surface. In employing an elliptical or
flattened tube as an external tube, I prefer to introduce two internal fire tubes.
These both pass through terminal boxes of a character similar to those previously
described; and together with the external tubo are secured in position relatively
to such boxes and tube by screw ferrules, nuts, collars or other suitable fastenings.
When making use of this flattened water tube and double internal fire tube type
of section, I prefer to employ a somewhat different method to that previously
described for securing together the sections forming each tier. Instead of arranging
the connecting and tightening bolt or bar outside or between one tier of sections
and its laterally adjacent tier (in which latter case the tightening action is divided
over the two tiers affected,), I pass the said bolt through the whole series of
terminal boxes at one end of the tier and between each pair of internal tubes
*contained in the several sections. The series of terminal boxes at the other end
of the tier is provided with a similar through-bolt applied in the same manner.
The packing of the ends of the external and internal tubes in the terminal boxes
may also, if preferred, be effected by means of caoutchouc or other pliable rings,
constructed on the cup leather principle, and arranged in recesses respectively
formed in the back and front of the terminal boxes; the fluid under pressure
being admitted to the interior of such packing rings.
According to the power the boiler is required to develop, a sufficient number of
units or sections, constructed in accordance with one or other of the methods
hereinbefore described, are arranged together in a suitable manner relatively to the

page_text: fire grate. The terminal boxes are by preference of rectangular shape in end view;
so that, being in contact with or close to one another both altitudinally and
laterally, they leave no important interstices through which the products of com-
bustion can escape; 'but form a practically compact wall at each end of the fire
chamber, through which the products of combustion first pass. In this chamber
the outer surfaces of the external tubes are exposed to the heated products of
combustion, which, in traversing the said chamber, circulate amongst these tubes
and then pass under, over or around one of the said end-walls described above as
composed of terminal boxes. The products of combustion then gain access to the
internal tubes of the various sections, through which they pass, and ultimately find
their way to the smoke flue or chimney. To promote effective distribution of the
heat throughout the fire chamber and amongst the tubes, directing plates may be
interposed horizontally or otherwise between the tubes and arranged in such a
manner as to cause the heated products of combustion to follow a zig-zag or
circuitous course before reaching the internal tubes.
By a somewhat different arrangement of the sections relatively to the furnace,
the products of combustion may, if preferred, be caused to pass first through the
internal tubes and subsequently amongst the external tubes.
::
In order to effect the application of the heat primarily to the external tube
surface and ultimately to the internal tube surface, or vice versa, it will be con-
venient to partially or wholly enclose the boiler in a brickwork or other suitable
casing. At the ends of this casing doors may be arranged to open and permit of
the sections and their fastenings being examined, removed, repaired or renovated;
or of the interior of the fire tubes being cleaned.

page_text: '
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Gatton Melhuish Hardingham in the Great Seal Patent
Office on the 18th April 1883.
GEORGE GATTON MELHUISH HARDṛngham, of 191, Fleet Street in the County
of Middlesex, Civil Engineer "IMPROVEMENTS IN STEAM BOILERS."
My invention relates to the class of steam boilers commonly called "sectional,”
that is to say, boilers whereof the major portions are composed of a number of
units closely resembling one another in design and arranged to work in unison;
each of such units or sections being of a size, construction and weight convenient
for manufacture, handling, transport, erection, &c; as also for being dismounted,
repaired and replaced when necessary.
Each section of my improved boiler consists of a tube furnished at each end with
a chamber or transverse passage and containing an internal tube or tubes passing
longitudinally through the first named tube and its and chambers. Each such
section communicates with that respectively above and below through its end
chambers; the joints hereon being so arranged, packed and fastened as to render
the sections readily separable.
In constructing a boiler according to my invention, several sections, such as
above described and of uniform length, are piled one above the other, and several
piles or vertical tiers so formed may be placed side by side; the terminal chambers
of one pile being laterally in contact with or close to those of the adjoining pile.
For securing the sections together when formed into a pile, I pass between each
two piles of laterally contiguous sections (and outside in the case of an outside pile)
a bolt or bar, to which a nut or other adjustable fastening is subsequently applied.
Such bolts or bars are introduced at both ends of the sections and may be con-
veniently arranged in recesses formed in the sides of the terminal chambers. Or
connecting bolts, instead of being applied externally, inay be passed through the
terminal chambers constituting the extremities of each such pile; in which case I
prefer to arrange the bolt so as to traverse the waterways through which the
terminal chambers communicate with one another. Or, instead of a continuous
bolt or bar being employed for this purpose, independent fastenings may be applied
at each joint between the terminal chambers. Or, according to another method of
construction, the extremities of any two sections required to communicate with
one another present faces perpendicular to the axes of the said sections, to which
faces are applied hollow connecting pieces extending from the face of one section
to that of the next and serving also to secure such sections together. In any case,
the joints between or upon the sections are provided with caoutchouc or asbestos
rings or washers or other suitable packing of a somewhat yielding character; and
when continuous bolts are employed, as bereinbefore described, I prefer to interpose
a strong spring under the head or nut of such bolt in order to permit of the
terminal chambers expanding under increased temperature without unduly
compressing the packings or straining the bolt.
According to the power the boiler is required to develop, a sufficient number of
sections, constructed and connected with one another as herein described, are
suitably mounted relatively to the fire-grate. The terminal chambers are by
preference of rectangular or hexagonal shape in face view (or made up by means
of wings to such shape); so that being in contact with or close to one another
both altitudinally and Interally, they leave no important interstices through the
products of combustion can escape endwise, but forin a practically compact wall at
each extremity of the fire-chamber, through which the products of combustion first

page_text: pass and in which the outer surfaces of the external tubes are exposed to the heat.
The products of combustion then pass over or around one of the said end walls
described above as composed of terminal chambers, and gain access to the.internal
tubes of the various sections, through which the said products pass and ultimately
find their way to the smoke-flue or chimney. To promote effective distribution
of the heat throughout the fire-chamber and amongst the external tubes, directing
plates may be interposed between the rows of sections in such a manner as to cause
the products of combustion to follow a zig-zag or circuitous course before reaching
the internal tubes. In cases where the internal tubes are of inadequate area to
permit the passage of the whole of the products of combustion with sufficient
freedom, I cause only a portion thereof to traverse the internal tubes and the
remainder to pass by another route or routes to the chimney; this portion being
'utilised, however, for superheating, the steam, or for heating the feed-water or för
both or other useful purposes.
By a somewhat different arrangement of the sections relatively to the furnace,
the products of combustion may, if preferred, be caused to pass first through the
internal tubes and subsequently amongst the external tubes.
In order to effect the application of the beat primarily to the external to the
external tube surface and ultimately to the internal tube surface, or vice versa, the
boiler is partially or wholly enclosed in a brickwork or other suitable casing. At
the ends of this casing doors may be arranged to open and permit of the sections, or
of their fastenings or inner tubes, being examined, removed, repaired or renovated,
or of the interior of the tubes being cleaned.
DESCRIPTION OF THE DRAWINGS.
Fig 1 represents a side elevation of a boiler constructed in accordance with my
invention (one side of the surrounding casing being removed); and Fig. 2 an end.
elevation thereof (a portion of one of the front doors being removed). A is the
fire-grate and B the front frame. C is a stiff bar carried at its extremities in the
side walls Z, Y. Upon this bar is mounted one end of the boiler D. The other
end thereof rests upon the front frame B, or upon a transverse bar E similarly
carried in the side walls, or upon both these supports; and is free to slide
longitudinally thereon as expansion and contraction, due to variation of tempera-
ture, take place. A chamber or drum F, carried at f¹ f2, receives the feed-water
and distributes the same to the several piles of sections composing the boiler. These
are retained in position laterally by being attached to the fixed plate C at one end,
and the sliding plate c' at the other end; they may also be connected together at
their upper back ends by the plate 2 From the upper front end of each pile of
sections, a pipe G passes to a super heater H, which the steam traverses before reaching
the main steam pipe I. The heated products arising from the combustion of the fuel
on the grate A circulate amongst the outer tubes, passing round the ends of the
directing plates J J. The plate M preventing the escape of the products of
combustion direct to the flue or chimney X, a portion thereof passes over or around
the back end of the boiler D'and gains access to the internal tubes of the various
sections, through which the products pass to the front of the boiler and thence to
the said flue or chimney X. In the design employed for the purpose of illustration,
another portion of the products of combustion operate on the superheater H, and,
passing round the end of the directing plate K, also find their way to the flue;
whilst the remainder are led by a flue W to a chamber V, which they traverse before
escaping by the flue U to the main flue X. In the chamber V is arranged a feed-
water-heater L. The front of the chamber enclosing the boiler is provided with a
door or doors T and the back thereof with doors S. S.
In Figures 3, 4 and 5 is represented in detail one mode in which I construct the
sections of my improved boiler; Figure 3 being partly an end elevation of and partly
a transverse section through terminal chambers of such sections, Figure 4 a part plan
and part horizontal.section of such a chamber and Figure 5 a part side elevation and

page_text: part vertical section thereof. a is the outer tube, screwed in the terminal chamber b.
This chamber is provided with water ways or passages cc and is connected by
packed joints d with the sections above and below respectively; being fastened
thereto by means of bolts and nuts or their equivalents. The opposite end of
the outer tube being provided with a terminal chamber of similar construction, an
inner or fire-tube f traverses the said outer tube and end-chambers. The
extremities of the inner tube may be secured in the outer faces of the terminal.
chambers in various ways; but, in order to render the said inner tube readily
removeable, I prefer to provide it with gland packings of the type indicated;
wherein the orifice in the outer face of the terminal chamber is considerably larger
in diameter than the inner tube (which can thus be removed when encrusted with
scale); whilst the stuffing-box is fitted with a loose ring g underneath the soft
'packing g', a second loose ring g' being interposed between the latter and the
screw-gland ghh are wings extended laterally for the purpose of intercepting
the passages which would otherwise exist between the teriminal chambers of the
contiguous sections, and through which the products of combustion would escape
longitudinally.
Figures 6 and 7 ahew in vertical and horizontal section respectively, Figures:8
and 9 in side elevation and plan respectively and Figure 10 in transverse section,
(as regards the tubes) another mode in which I construct compound water and
fire-tube sections for sectional boilers.. According to this modification, I substitute
for the external cylindrical tube (a in the foregoing description) an elliptical or
flattened tube a; and I introduce two internal fire-tubes ff, which pass through
terminal chambers b of a character similar to those previously described; the said
internal tubes terminal, chambers and external tube being secured together,
relatively to one another by gland nuts g³ or other suitable fastenings acting in
conjunction with the inner tubes. In jointing the terminal chambers to the outer
tube, I employ an automatic packing on the cup leather principle. This is shown
to an enlarged scale in Figure 11, where a is the end of the outer tube, bis a
portion of the terminal chamber provided internally with a recess or groove, in
which is located the ring j formed of caoutchouc and asbestos or other pliable and
suitable material. The fluid under pressure finds its way into the interior of the
cup-packing j, and the usual effect ensues. In connecting sections of the present
description together, a through bolt el may be employed, traversing the radial
water ways c, c, of a series of terminal chambers and passing between each pair of
internal tubes contained in the sections severally.
Figure 12 represents an end elevation, and Figure 13 a part plan and part horizontal
section, of a further modification. In this instance, the outer or water-tube a and
its terminal chambers bare traversed by four internal or fire-tubes f, the extremities
whereof are shown.(by way of example) expanded in the tube-plates of the said
chambers in accordance with one of the modes commonly employed for fixing
boiler-tubes. In this illustration, provision is made for securing the sections
together by means of continuous bolts applied externally as herein before referred
to, the recesses ok being intended for the reception of such bolts.
Figures 14 and 15 are illustrative of another method I employ in constructing
and connecting together the sections of my improved boiler; the former being a
front view of two such sections (the upper portion of the outer connecting-picce
being removed) and the latter a vertical section. a a are extremities of the outer
tubes of two adjacent sections which (as before) are required to communicate with
each other and respectively with the sections next above and next below. The
tube a is screwed or fastened in a socket-plate which presents a face perpendicular
to the axis of the said tube. To the packed face of the socket-plate is applied a
short cylinder, tube or ring m, communicating, by means of a radial passage m²,
with a similar cylinder m³, intended to occupy a corresponding position in relation
to the next section either above or below as the case may be. To the outer face
of the short cylinder m is applied the packed face of a connecting-piece ; the latter
communicating by means of a similar packed face with the inner connecting-pieco

page_text: of the section next in order, but in the opposite direction to that in which the inner
connecting-piece previously referred to, communicates directly. An inner or fire-'
tube ftraverses the external tube a and socket plate / as well as the inner and outer
connecting pieces m, n, and is packed with a screw-gland g, or other suitable
fastening, in the external face of the outer connecting-piece n. On tightening the
said gland upon the inner tube, the outer connecting-piece is pressed against the
face of one of the cylinders (m) of the inner connecting-piece, whilst the latter is
in turn pressed against the face of the socket-plate 1. The inner tube, being
similarly fastened at its opposite end, acts as a stay to secure together the three
pieces l, m, n, of which the terminal chamber may, in this instance be deemed to
consist. Communication is thus established between the socket of one section and
that of another, either by way of the direct passage between the cylinders m
and m² of the inner connecting-piece, or through one of such cylinders (m) through
the outer connecting-piece (n) and thence back through one of the cylinders (m)
of the next inner connecting-piece. In some instances, in order to reduce or
obviate the strain on the inner tube necessary for making steam-tight joints on
the faces of the inner connecting-piece, I provide the socket plate and the outer
connecting-piece n respectively with lugs o, o' and apply bolts and nuts por
equivalent fastenings, by the aid of which the joints referred to may be made
secure independently of the inner tube. A side elevation of such a supplementary or
alternative fastening is shown in the detached view Figure 16-Figure 17 represents
a transverse section through the outer and inner tubes a, f, shewing the socket-
plate in back elevation. Upon removing the connecting-pieces and withdrawing
the inner tube, the interior surface of the outer tube is rendered accessible for
cleaning purposes.
When continuous bolts are used for connecting the sections together, as for
example with the types illustrated by Figures 6 and 13, the latter are necessarily
arranged in a direct line one above another. When however, certain other
methods of connections are employed, as for example that indicated in Figures 14
and 15, the sections may be arranged as shown diagrammatically in the face view
Figure 18; it being generally considered that the flow of the heated gases amongst
the outer tubes becomes more completely broken up and the heat more effectually
absorbed therefrom when the sections are arranged in such a manner. In this
diagram are the socket-plates, such as described with reference to Figures 14, 15
and 17, fare inner tubes and m, n respectively the inner and outer connecting-
pieces for establishing communication between each section and the next' in order.
Instead of the sections being rectangular in end view, they may be hexagonal, as
indicated towards the right hand lower portion of this diagram. The spaces q
are filled in to prevent the heated products of combustion escaping therethrough.
Having thus fully described, the nature of my invention and in what manner
the same is to be performed, I would have it understood that I do not confine
myself to the precise details of construction or the combinations severally
represented in the drawings hereunto annexed, as many of these may be varied
without departing from the principle of my invention. I further declare that I .
make no general claim to sectional boilers, each section of which consists of an
outer or water-tube.communicating at each end with the section next in order and
traversed longitudinally by an inner or fire-tube or several such tubes. Neither
do I claim the combination of two or more tubes, carrying internally the concentric
removeable fire-tubes, with an upper.boiler; as I am aware that such an arrange-
ment was proposed in the specification to Letters Patent granted to Sir William
Fairbairn, Bart, A.D. 1870, N° 810; but I claim in respect to boilers of the kind
first above referred to:-
First Constructing each section of an outer or water-tube of malleable metal
communicating at each end with a cast metal chamber or transverse passage and
having a malleable metal inner or fire-tube or several such tubes passing longi-
tudinally through the outer tube and the end-chambers or passages; the said end-
chambers or passages of one section being connected to those of another by

page_text: separable packed joints, substantially as herein described with reference to the
accompanying drawings.
Secondly Jointing the outer tubes to their terminal chambers with cup-
packings, their junctions being secured by the inner tubes acting as stay-tubes,
substantially as described with reference to Figures 6 to 11.
Thirdly. Constructing each terminal chamber in three parts, two of such parts.
being connected respectively to parts of the chambers of the sections below and
above by packed joints on faces perpendicular to the axis of the tubes, substantially
as described, with reference to Figures 14 to 17:
•
In witness whereof I; the said George Gatton Melhuish Hardingham, have
hereunto set my hand and seal this seventeenth day of April in the year
of our Lord One thousand eight hundred and eighty three.
G GM HARDINGHAM (L.§.)