IMPROVEMENTS IN STEAM BOILERS
Year: 1879

page_text: LETTERS PATENT to John Griffiths Hughes, of Sunderland, in the County of
Durham, Engineer, for the Invention of "IMPROVEMENTS IN STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said John Griffiths Hughes at the
Office of the Commissioners of Patents on the 8th April 1879.
JOHN GRIFFITHS HUGHES, of Sunderland, in the County of Durham, Engineer.
"IMPROVEMENTS IN STEAM BOILERS."
My Invention relates to improvements in steam boilers whereby an increased
amount of heating surface is obtained, the consumption of fuel is economized by
utilizing the gases and converting them into flame, and greater strength and
durability are secured combined with simplicity of construction and safety in the
use of the boiler.
In carrying out my Invention as applied to the construction of a boiler with two
internal furnace flues the flues are turned upwards at their rear ends, and then
returned to the front end of the boiler, where they are united to a single tube,
which is carried backwards, and at its rear end passes through a feed water cistern,
and thence is connected to the chimney. The flues are provided with water tubes
extending across them for the purpose of promoting a circulation and obtaining
increased heating surface, and the flues may also be corrugated, in order to obtain
an increase of heating surface.
The air for supporting combustion is admitted to the furnaces by two cases
arranged in relation to the respective fire doors, so as to be capable of being raised
and lowered by means of guide rods, pulleys, and chains as required. These cases
are open on the underside for the admission of the air, and after the furnaces have
been fired (which operation takes place with respect to the two furnaces alternately),
the case is brought down over its respective fire door on to a plate provided with
adjustable air openings communicating with the exterior, the fire door being

page_text: retained in any required position by guides on the case.
When the fire has cleared
the fire door may be closed, and the case drawn up if necessary.
By the arrangement of flues with the alternate stoking of the furnace the heated
air and clear flame of one furnace is rendered available for consuming the smoke
from the other furnace, so that no carbonic acid is allowed to escape into the
chimney. If desired a single air case may be employed, arranged so as to slide on
rollers transversely across the front of the two furnace doors alternately.
In order to prevent priming a perforated plate with adjustable openings may be
interposed in the steam passage, the said plate being covered with a dome or
hood.
Sludge pots or pans are provided of small capacity, so as to admit of ready
removal.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Griffiths Hughes in the Great Seal Patent Office on the
1st September 1879.
JOHN GRIFFITHS HUGHES, of Sunderland, in the County of Durham, Engineer.
"IMPROVEMENTS IN STEAM BOILERS."
My said Invention relates to improvements in steam boilers whereby an increased
amount of heating surface is obtained, the consumption of fuel is economized by
utilizing the gases and converting them into flame, and greater strength and
durability are securod combined with simplicity of construction and safety in the
use of the boiler.
In carrying out my said Invention as applied to the construction of a boiler with
two internal furnace flues the flues are turned upwards at their rear ends and then
returned to the front end of the boiler, where they are united to a single tube, which
is carried backwards, and at its rear end passes through a feed water cistern, and
thence is connected to the chimney. The flues may be provided with water tubes
extending across them for the purpose of promoting a circulation of the water and
obtaining increased heating surface, and the flues may also be corrugated, in order
to obtain an increase of heating surface.
The air for supporting combustion is admitted to the furnace by means of a
sliding box or case arranged so as to be capable of being shifted transversely across
the end of the boiler from one furnaco to the other when being fired. This box or
case is open on the underside for the admission of the air, and after the furnaces
have been fired (which operation takes place with respect to the two furnaces
alternately), the box or case, which slides over a plate provided with adjustable air
openings, is brought over the fire door of the furnace last charged, and so allows
air to be conducted into the said furnace for the purpose of converting the gas into
flame. The fire door may be retained in any required open position by guides on
the case, and when the fire has become clear the fire door may be closed and the
case removed across the furnace end to perform a similar operation in the next
furnace.
By the arrangement of flues herein before described with the alternate stoking of
the furnaces the heated air and clear flame of one furnace is rendered available for
consuming the smoke from the other furnace, so that no carbonic gas is allowed to
escape into the chimney unconsumed.
In order to prevent priming I interpose in the steam passage a perforated plate,
the said plate being covered with a dome or hood which arrests any liquid which
may pass with the steam through the perforations, and cause it to return to the
boiler. I also provide sludge pots or pans at the lower part of the boiler to collect
the deposit, the said pots or pans being of small capacity, so as to admit of ready
removal when required.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a front elevation of a double
furnace boiler constructed according to my said Invention. Figure 2 is a longi-
tudinal section of portions of the two opposite ends of the same; and Figure 3 is a
horizontal section corresponding to Figure 1.
A is the shell or body of the boiler; B, B1, the two furnaces or fire places fitted
with firo doors a in the ordinary manner. The furnaces B, B, extend backwards to
within a short distance of the rear end of the boiler, where they are connected to
two vertical or nearly vertical flues C, C¹, which form continuations of two hori-
zontal flues D, D¹, the latter extending from the rear to the front end of the boiler,
and communicating with each other at that end by a transverse flue E. This flue

page_text: is connected to another horizontal flue F, which is arranged between the two flues
D, D', and extends from the flue E through the back end of the boiler into a feed
water tank or hot well G, and thence rises vertically therein to the chimney H.
It will thus be seen that the products of combustion from the furnaces are caused
to travel to and fro, or in a circuitous course from one end of the boiler to the other
end thereof, whereby their heat is absorbed by the water surrounding the flues and
the water contained in the tank G before they enter the chimney. Water tubes I
may be arranged across the flues D, D¹, and E, as shown, for the purpose of increasing
the heating surface, and for promoting a circulation of the water, whereby the said
water becomes more rapidly heated.
Air for supporting combustion in the furnaces is admitted and regulated in the
following manner-
K is a box or case which is open on the underside, and is fitted to slide upon
rollers N transversely across the boiler end from one furnace to the other. The
case K travels over a perforated plate L arranged in front of and immediately below
the furnace mouths, beneath which plate and fitted to slide in contact therewith
are plates ff, provided with perforations corresponding with the perforations in
the plate L, so that by sliding the plates f, f, in their guides g, g¹, the perforations
in the plate L may be more or less contracted or entirely closed, and the passage of
air therethrough be regulated or entirely excluded, as required.
The furnaces are fed with fuel alternately, and after a charge of fuel has been
introduced into one of the furnaces the case is traversed over the perforated plate L
into position opposite the door of the said furnace. Assuming, for example, that
the furnace B has just received a fresh charge of fuel, its fire door a is left open or
partially open, and the case or box K is brought over the fire door; the plate fis
then adjusted so as to admit of the necessary passage of air through the perforations
in the plate L into the furnace, in order to effect the combustion of the fuel; so soon
as the fuel in the furnace B has become incandescent the case may be shifted and
the furnace door closed, the air passing through the fire grates from the ash pit
being all that is then necessary.
The furnace B' is next charged with fuel, and the case or box K shifted across as
herein before described, so as to cover the fire door, and the admission of air to the
said furnace is then regulated by the plate f¹ in a similar manner to that described
with reference to the furnace B. The smoke and gases from the fuel in the
furnace B¹ in their passage towards the chimney H are met at the junction of the
two flues D, D¹, in the transverse flue E by the heated products of combustion from
the furnace B whereby the complete combustion of such smoke and gases is effected
and the admission of carbonic gases into the chimney prevented.
In order to prevent priming I provide in the base of the steam dome M, Figures
1 and 2, a perforated plate N. At a short distance above the plate N I arrange a
dome or convex plate P of such a size as to leave a narrow annular space k for the
passage of the steam between the edge of the plate P and the sides of the dome M.
The steam passing from the boiler into the dome M through the perforated plate N
is caused to impinge against the underside of the convex plate P on its way to the
engine, whereby any water conducted along with the steam from the boiler is
arrested, and thence returns to the boiler through the perforations in the plate N,
and priming is thereby prevented.
In order to diminish the tendency to the accumulation of impurities or calcareous
or other deposits from the water on the shell of the boiler I provide pots Q (Figures
1 and 2) which are arranged along the bottom of the boiler for the reception of
such impurities or deposits. These pots are by preference made of small dimensions,
in order to facilitate their removal, which may be effected by disconnecting the
cover R from the opening S, through which the pots may be withdrawn and replaced
by the aid of any suitable instrument.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and

page_text: therefore claim as the Invention secured to ine by the hereinbefore in part recited
Letters Patent is,-
First. The combination with two furnaces of a system of circuitous flues united
in a main flue common to the two furnaces, the said flues being arranged and com-
bined with the other parts of the boiler, substantially in the manner and for the
purpose herein before described.
Secondly. The employment of an air case arranged so as to operate substantially
in the manner and for the purpose herein before described.
Thirdly. In a double furnace boiler the combination with converging circuitous
flues of an air case so arranged as to admit of the furnaces being fired alternately,
substantially as hereinbefore described.
Fourthly. The peculiar apparatus or devices for preventing priming in steam
boilers, substantially as hereinbefore described.
Fifthly. The employment in steam boilers of portable sludge pots or receptacles,
substantially as hereinbefore described.
In witness whereof, I, the said John Griffiths Hughes, have to this my Speci-
fication set my hand and seal, the Twenty seventh day of August, One
thousand eight hundred and seventy nine.