IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF STEAM GENERATORS
Year: 1884

page_text: I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the County
of Middlesex, Civil Engineer, do hereby declare the nature of said invention for
"IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF STEAM GENERATORS to
be as follows:-
12
The object of my present invention is to secure improved economy in the
working of steam generators; the devices and means I employ to this end being of
the following general description. First, I intercept a considerable portion of the
heat tending to radiate and escape into the surrounding atmosphere and apply the
same to heat the air supplied to the furnace of the generator. Secondly, in
sectional boilers I employ means whereby certain of the impurities commonly
contained in the feed-water are separated. therefrom before the latter passes into
circulation; incrustation of the heating surface being thereby prevented or
considerably modified and interference with the effectiveness of such heating
surface being correspondingly avoided. Thirdly, in sectional boilers of the type
described in the specification to Letters Patent granted to me A.D. 1882., N° 4956,
I cause the heated gases during their passage through the inner or fire-tubes to
flow in the opposite direction to that appertaining to the water in course of
circulation through the surrounding water-tubes, by which means the heating
effect on the water is improved, whilst the liability for dust to become deposited in
the inner or fire-tubes is diminished.
With a view to intercepting heat tending to radiate and escape from steam
generators wholly or partially enclosed or mounted in a brick work or other chamber
casing or setting, I construct the sides of such chamber casing or setting with a
double skin, an air-space passage or passages being formed between the two sking.
Air enters this intermediate space or passage by preference at its upper part, and is
caused to pass downwards or towards the ash-pit, where it is introduced beneath
the fire-bars or otherwise supplied to the furnace. In order to produce the
requisite current towards the furnace, a fan, blower or other suitable means, may
be employed, either to force the air into the space passage or passages described or
to educt it therefrom. Thus the heat which would otherwise have been lost by
radiation through the sides of the chamber or casing, is intercepted and absorbed
by the air current; and this being subsequently fed to the furnace, the heat it
Price 1

page_text: contains is utilized. Further, the brickwork or other casing is maintained at a
moderate temperature.
The means I employ for avoiding incrustation of the heating surface by
impurities contained in the feed-water are of the following description. It is well
known that at a temperature somewhat below the boiling point of water, certain
of the impurities commonly occurring in feed-water become solidified; and this
part of my invention relates to means for effecting the solidification of such
impurities and their removal or separation from the water before the latter, passing
into circulation, enters the steam-generative portion of the boiler. Supposing this
part of my invention to be applied to a boiler of the sectional class and one in
which each series of sections communicates with a water and mud-drum below and
with a steam and water-drum above, I introduce the feed-water into the upper
drum and there expose it in open pipes or receptacles or spread over surfaces or
divided in thin streams to the action of the steam, whereby the water becomes
heated to the temperature requisite for solidifying the impurities before alluded to.
These subside in the upper or steam-drum and pass by a pipe or pipes to the lower
or mud-drum, whence they are occasionally blown off or otherwise removed. The
water intended to pass from the upper drum into circulation enters a pipe, the
open end of which, although beneath the level of the water in the upper drum, is
placed as far as possible above, and as remote from, the impurities deposited in the
said drum. This pipe communicates with a tube arranged within the lower or
mud-drum; or, if preferred, more than one pipe may be employed to convey the
water to the said tube. The mud-drum-tube is provided with branches, nozzles or
orifices, respectively opposite to and immediately against the several openings from
the lower drum to the various series of sections. The water intended for
circulation through each series of sections is accordingly drawn froin each branch,
nozzle or orifice, of the tube arranged within the lower drum, which tube in turn
obtains its supply from the purer portion of the water contained in the upper
drum.
The connection or communication between each branch, nozzle or orifice, of the
mud-drum-tube and its corresponding series of sections is preferably not of a
water-tight character; so that, should the water level in the upper drum be
accidentally allowed to fall below the upper extremities or inlets of the circulating
water supply-pipe or pipes, the sections or steam-generative portion of the boiler
will still be able to draw water from the lower druni, and thus prevent or diminish
the risk of injury to the generative portion of the boiler by overheating whilst
short of water.
For convenience in construction, I prefer to arrange the pipe or pipes conveying
the circulating water from the upper drum to the sections or steam-generative
portion of the boiler within the pipe or pipes connecting the upper drum with the
lower one.
Under such circumstances, the solidified impurities pass to the mud-
drum by way of the annulus formed between the two vertical or otherwise
disposed communicating pipes.
According to a modified arrangement for effecting the purpose last referred to,
instead of exposing the feed-water to the direct action of the steam in the upper
drum, I cause the same to pass through a coil or other suitable conduit arranged in
the upper drum and exposed to the steam therein. The outlet from this coil is
inserted in and extends some distance down the pipe communicating with the
mud-drum. The impurities in the feed-water, having become solidified during the
passage of the same through the coil or other heating contrivance, are thus
discharged at a point whence they readily find their way to the mud-drum; and
are not liable, in consequence of the water in the upper drum being in a state of
agitation, to be carried to the inlet or inlets of the pipe or pipes conveying water
to the sections or generative portion of the boiler.
My invention so far as specially applicable to sectional boilers of the type
described in the specification to the aforesaid Letters Patent of A.D. 1882.,
No 1956 that is to say, boilers whereof each section consists of an outer or

page_text: water-tube cominunicating at each end with the section next in order and traversed
longitudinally by by an inner or fire-tube or several such tubes-relates to an
improved mode of working or conducting the heated gases through the generator
in relation to the direction of flow pursued by the water in course of circulation.
On referring to the drawing forming part of the aforesaid specification, it will be
observed that the arrangement of the generator is such that the heated gases, after
being applied to the external surfaces of the outer tubes, are caused to pass over
the back wall composed of terminal chambers, and then to enter the inner tubes at
their lower ends, escaping from the same at their upper ends. The direction of
flow of the water contained in the sections is also from their back or lower ends
towards their front or upper ends, thus coinciding with the direction of flow of the
gases during their passage through the inner tubes. Instead of this mode of
working, I so arrange the generator within its casing, or so construct the passages
for the guidance of the heated gases, that these are conducted to and enter the
inner tubes at their upper ends and escape therefrom at their lower ends; thus
traversing the sections in a direction opposed to that pursued by the water in
course of circulation. The back end of the generator and the lower ends of the
fire-tubes are in communication with the flue, the draught whereof causes the
heated gases to follow the downward course described. Artificial means, such for
instance as herein before described, may however be employed to produce the
requisite draught.
By causing the fluids (i.e. the heated gases and the circulating water) on the
respective sides of the medium to flow in opposite directions in the manner
described, a larger proportion of the heat is absorbed by the water from the gases,
increased economy being thereby secured. A further advantage appertaining to
the improved mode of working described is that the gases, passing in a downward
direction through the inner tubes, act in conjunction with gravity to sweep out
dust tending to become deposited therein. Where, on the other hand, the flow of
the gases is in an upward direction and therefore opposed to gravity, the tendency
is for dust to accumulate more rapidly; the result being that the conductivity of
the heating surface is impaired, and the draught interfered with in consequence
of the effective tube-area.becoming contracted.
Dated this 3rd day of January 1884

page_text: وو
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
County of Middlesex, Civil Engineer, do hereby declare the nature of my invention
for "IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF STEAM GENERATORS
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The object of my present invention is to secure improved economy in the
working of steam generators; the devices and means I employ to this end being of
the following general description.
First; I intercept a considerable portion of the heat tending to radiate and escape
into the surrounding atmosphere, and apply the same to heat the air supplied to
the furnace of the generator. Secondly, in sectional boilers, I employ means
whereby certain of the impurities commonly contained in the feed-water are
separated therefrom before the latter passes into circulation; incrustation of the
heating surface being thereby prevented or considerably modified and interference
with the effectiveness of such heating surface being correspondingly avoided.
Thirdly, in sectional boilers of the type described in the specification to Letters
Patent granted to me A.D. 1882, N° 4956, I cause the heated gases, during their
passage through the inner or fire-tubes, to flow in the opposite direction to that
appertaining to the water in course of circulation through the surrounding water-
tubes; by which means the heating effect on the water is improved, whilst the
liability for dust to become deposited in the inner or fire-tubes is diminished.
And in order that my invention and the mode of carrying the same into effect
may be fully understood, I will, with the aid of the accompanying drawings, proceed
to describe a steam generator embodying the means I employ for procuring the
improved result before alluded to.
The design of generator adopted as convenient for the purpose of the present
illustration resembles in some respects that described in the specification to the
Letters Patent granted to me A.D. 1882, N° 4956; that is to say, it represents a
sectional boiler whereof each section consists of an outer or water-tube com-
municating at each end with the section next in order and traversed longitudinally
by an inner or fire-tube. Nevertheless, it is not to be inferred that my present
invention is applicable exclusively to steam generators of this type, except so far
as hereinafter specified.
Figure 1 is a part vertical section and part side elevation (one side of the
surrounding casing being removed); and Figure 2 is a half transverse section on
the line X X (Figure 1) and half front elevation of a sectional boiler embodying my
improvements. A is a group of sections constituting the steam generative portion
of the boiler; each vertical pile of sections being in communication with a water-
drum B below and with a steam-receiver C above. The drum B and the receiver C
are also connected by the pipes D D¹. Beneath the generator is arranged a fire-
grate E; e being the fire-door, el a fire-brick arch and e a fire-brick shield to the
drum B. Between horizontal rows of the heating tubes A are arranged directing
plates FF for the purpose of causing the heated gases to circulate amongst and
externally to the sections before passing over the higher part of the generator, as
indicated by the arrows, and gaining access to the inner or fire-tubes a with which
the sections are furnished and through which the gases have to pass before reaching
the flue G. An alternative and in some respects preferable form of baffle-plate is
shewn in the detached view Fig 1ª. The plate F is in this instance supported clear
of the tubes a¹ by means of diagonal ribs f resting upon two or more of the tubes.

page_text: These ribs diminish but slightly the flue area and offer the minimum resistance to
the flow of the gases. H H are doors provided respectively at the front and rear
of the brick or other chamber enclosing the generator, and by means of which
access is had for cleaning and other purposes.
Any
The water, whilst exposed to the heat arising from the furnace, is enclosed
between the inner tubes a and the outer tubes a¹; and these being placed at an
inclination, the steam rises towards their upper ends and passes by way of the
terminal chambers and connecting-pieces a and pipes c to the receiver C.
water carried over by the steam, as also the feed-water, finds its way by the
pipes D D to the drum B and hence to the sections; the circuit for the purpose
of circulation being thus complete.
With a view to intercepting heat tending to radiate and escape from steam
generators wholly or partially enclosed or mounted in a brick work or other chamber,
casing or setting, I construct the sides of such chamber, casing or setting, with a
double skin, an air-space passage or passages, being formed between the two skins,
as shewn in Figure 2 and in the horizontal section Figure 3. Air enters the inter-
mediate space or passage J, by preference at its upper part, and is caused to pass
downwards or towards the ash-pit, where it is introduced between the fire-bars, or
otherwise supplied to the furnace. The air-space J may also be open to the
atmosphere along its front or back edges or both. Openings; for this purpose are
shown in Fig. 2. In order to produce the requisite current towards the furnace,
a fan, blower or other suitable means, may be employed, either to force the air into
the space passage or passages described, or to educt it therefrom. I prefer the use
of a blower working on the steam-jet principle, and to arrange same as indicated
in the drawings before referred to; K being the blower with an inlet k, in com-
munication with the air-space J, and an outlet passing through the entire
side-wall and delivering the air beneath the fire-grate. Thus the heat which
would otherwise have been lost by radiation through the sides of the chamber or
casing is intercepted and absorbed by the air current; and this being subsequently
fed to the furnace, the heat it conveys is utilized. Further, the brick work or other
casing is maintained at a moderate temperature. Moreover, the air being supplied
at a slight pressure above the atmosphere, the tendency of the chimney-draught to
produce a partial vacuum within the chamber is neutralised; the induction of cold
air around the doors and through crevices being thus avoided..
A-por-
For diminishing or preventing incrustation of the heating surface by impurities
contained in the feed-water, I employ means of the character illustrated in Figs 4
and 5; the former being a transverse section through the water and steam-drums
and their connecting pipes as already described in reference to Figs. 1 and 2. B is
the water-drum and C the steam-drum carried on the side-walls L L of the
chamber enclosing the generator. (The latter is omitted from the figure). The
feed-water is introduced, preferably at a high temperature, by the pipe M.
tion of this pipe within the steam-receiver is open along its upper side and forms a
trough from which the water overflows. A similar, but larger trough M may be
arranged beneath to intercept the streams before they reach the main body of water
in the receiver; the object of this apparatus being to expose the feed-water to the
full heating effect of the steam contained in the receiver, and thereby to cause
certain of the impurities which are commonly present in such water to be solidified.
Various other means might be substituted for effecting the necessary exposure and
rapid heating of the feed-water. The solidified impurities subside to the bottom of
the receiver C and pass by way of the pipes. D D¹ to the water-drum B, whence
they are occasionally blown off by the cock b or otherwise removed. The major
part of the impurities baving been thus eliminated, the water intended to pass
from the drum C into circulation enters the upper end of the pipe N, which,
although beneath the level of the water in the drum C, is placed as far as possible
above and as remote from the impurities deposited in the said drum. The pipe N
communicates with a tube n arranged within the lower or water-drum B. The
opposite end of the tube n may be furnished with similar supply pipe N'.arranged

page_text: within the pipe D¹. The tube n is provided with branches n³, nozzles or orifices,
respectively opposite to and immediately against the several openings from the
drum B. to the various series of 'sections, as shown in the transverse section
Figure 5, where n² is a nozzle on the circulating-water-supply-tube n and a² a
connecting-piece communicating with one of the sections in the lower row of the
group constituting the generator A. The water intended for circulation through
each series of sections is accordingly drawn from each branch n² of the tube n
arranged within the drum B; the tube n in turn obtaining its supply through the
pipe N or N¹ or both from the purer portion of the water contained in the upper
drum C.
The connection or communication between each branch n² of the tube n and its
corresponding connecting-piece a² leading to the generator is preferably not of a
water-tight character; so that, should the water level in the upper drum be acci-
dentally allowed to fall below the upper extremities of the supply pipes N N¹, the
sections or steam generative portion of the boiler will still be able to draw water
from the lower drum B, the risk of injury by overheating being thereby
diminished.
According to a modified arrangement for effecting the separation of impurities
from the feed-water, instead of exposing the latter to the direct action of the steam
in the upper drum, I cause the same to pass through a heating coil arranged in the
said drum, as shewn in the vertical sections Figures 6 and 7; whereof Figure 6 is
a transverse sectional view corresponding with Figure 4, whilst Figure 7 represents
a transverse section of the steam-receiver on or about the line. Y Y, Figure 6. The
M is the
heating coil alluded to also appears in transverse section in Figure 1.
The feed-water
feed-inlet-pipe, and M¹ a coil terminating in a divided chamber m.
enters the compartment m' of this chamber, and, after traversing the coil, arrives in
the adjoining compartment m², whence it escapes by a pipe m³ at a point some
distance down the pipe D communicating with the lower drum B. The impurities
contained in the feed-water, having become solidified during the passage of the same
through the coil M¹, are thus discharged at a point whence they readily find their
way to the mud-drum, and are not liable, in consequence of the water in the steam-
drum C being in a state of agitation, to be carried to the inlet of the pipe D¹
conveying water by the way of drum B to the generative portion of the boiler.
A diaphragm b¹ separates the lower drum B into two compartments, and prevents
the impurities subsiding from the feed-discharge-pipe m³ mingling with the
circulating water conveyed by the pipe D¹ and drum B to the orifices 6 supplying
the various series of sections. The impurities are periodically discharged in the
form of mud by the blow-off-cock b; the opposite end of the drum B being furnished
with a drain cock 6*.
My invention, so far as specially applicable for. securing improved economy in
the working of sectional boilers of the compound water and fire-tube type described
in the aforesaid specification to Letters Patent granted to me A.D. 1882, No 4956,
consists in the improved construction represented in Figure 1; whereby the gases,
during their passage through the inner or fire-tubes, are caused to flow in the
opposite direction to that pursued by the water in course of circulation through
the surrounding water-tubes. On referring to the general drawing forming part
of the aforesaid Specification, it will be observed that the arrangement of the
generator is such that the heated gases, after having been applied to the external
surfaces of the outer tubes, are caused to pass over the back wall composed of
terminal chambers, and then to enter the inner tubes at their lower ends. The
direction of flow of the water contained in the sections is also in that case from the
back or lower ends of the tubes towards their front or upper ends, thus coinciding
with the direction of the flow of the gases during their passage through the inner
tubes. According to my improved construction and mode of working, I arrange
the generator A within its casing, or so construct the passages for the guidance of
the heated gases, that these, after circulating amongst the sections and bathing the
external.tubes a¹, pass over or. around the front wall a of the generator and enter

page_text: the inner tubes a at their upper ends, as indicated by the arrows, escaping therefrom
at their lower ends. The back or lower ends of the fire-tubes are open to the
flue G; the draught thereof causing the heated gases to follow the downward
course described. Artificial means, such for instance as herein before described in
connection with the interception and utilization of radiant heat, may however be
employed to produce the requisite draught.
By causing the fluids (i.e, the heated gases and the circulating water) on the
respective sides of the medium to flow in opposite directions in the manner described,
a larger proportion of the heat is absorbed by the water from the gases; whilst the
latter, passing in a downward direction through the inner tubes, act in conjunction
with gravity to sweep out dust tending to become deposited therein. Where, on
the other hand, the flow of the gases is in an upward direction and therefore
opposed to gravity, the tendency is for dust to accumulate more rapidly; the result
being that the conductivity of the heating surface is impaired and the draught
interfered with in consequence of the effective tube-area becoming contracted.
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
First-In steam generators enclosed or mounted in a brickwork or other
chamber or setting, the method of and means for at once both intercepting and
utilizing radiant heat and avoiding the induction of cold air, substantially as
described with reference to Figures 1, 2 and 3 of the accompanying drawings.
Secondly-In sectional steam generators, the means for eliminating impurities
from the feed-water before the latter passes into circulation, arranged and operating
substantially as described with reference to Figures 4 and 5.
Thirdly-In sectional steam generators, the modified arrangement of apparatus
for the purpose referred to in the last preceding claim and operating substantially
as described with reference to Figures 1, 6 and 7.
Fourthly-In sectional steam generators of the compound water and fire-tube
type, the use of fire-tubes inclining downwards, substantially as described with
reference to Figure 1 and for the purposes specified.
Fifthly The steam generator, having water and fire-tubes disposed in the
manner alluded to in the last preceding claim, provided with means for the
interception and utilization of radiant heat and the prevention of cold air induction,
and furnished with apparatus for purifying the feed-water before the latter passes
into circulation; the whole constructed and operating substantially as described
with reference to the accompanying drawings.
Dated this 26th day of September 1884.