IMPROVEMENTS IN AND RELATING TO STEAM BOILERS
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office
of the Commissioners of Patents on the 28th September 1877. (A com-
munication from abroad by Messieurs Ch. Bourgois and L. Bouchez, trading as
such, of Arras, France, Manufacturing Engineers.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN AND RELATING TO STEAM
BOILERS." [A communication from abroad by Messieurs Ch. Bourgois and L. Bouchez,
trading as such, of Arras, France, Manufacturing Engineers.]
This Invention relates partly to boilers of that class known as Cornish boilers,
which have one or two interior tubes. The extensive use of these boilers is due to
the peculiar advantages they afford, namely, the reduction to a minimum of the
loss of caloric by the interior, furnace, the great mass of water they can hold, the
alow combustion and consequent economy of fuel, and the great facility they afford
for the construction of the brickwork or masonry. They have however serious
defects; for instance, their combustion chamber is very insufficient, so that the gases
are imperfectly consumed, the surfaces of the tubes are so near the place of com-
bustion as to greatly diminish its activity, the heating is not according to sound
principles, and there is a continual conflict between the water and the steam pro-
duced, a conflict which causes serious loss of mechanical effect.
The object of this Invention is to obviate these defects by the application to
Cornish boilers of an apparatus for improving combustion and regulating the
circulation, and consisting of a spacious cylindrical furnace, which is an essential
condition in an apparatus which is required to resist pressure and to be durable and
economical, and is surrounded by water in active circulation, carrying off rapidly
the great quantity of heat developed. This furnace ensures the combustion by
means of a supply of air, at one part for the solid portion of the fuel, and at another
part for the gaseous products which have passed through the grate. I thus effect
the heating on rational and methodical principles, at the same time realizing on a
large scale the effect of the circulating tubes of the well-known "Perkins" apparatus.
Moreover, as the fire-place is the part which is most exposed, it is rendered

page_text: completely independent of the other parts of the apparatus. And it must be
understood that this Invention is applicable to existing boilers.
In carrying this Invention into practice, the fire-places in the boiler tubes are
dispensed with, and at the front of the same is placed a large cylindrical casing
which is provided with an internal cylinder, forming the fire-place or furnace. I
fit the same with a grate properly proportioned to the total heating surface, and
thus obtain a spacious fire-place with a large combustion chamber. Above the said
casing of the fire-place is arranged a reservoir for water and steam attached by
plate or sheet-iron connections. The surfaces of the fire-place or furnace are
completely surrounded with water, and the level is established in the upper
reservoir.
Steam and water communication is established between the reservoir and boiler
by means of suitable pipes. The two levels of water in the boiler and reservoir are
rendered uniform by a valve and float. By these means the lower level is kept
constant. A plunger tube conducts the water to the bottom of the boiler. The
feed water enters the upper reservoir through a tube by means of a slide valve.
In addition to the direct communications where it is fixed on the furnace casing,
the upper reservoir is secured by four tubes to a set of tubes arranged below the
furnace.
On the direct communication tubes are fixed shect-metal trumpet mouths, which
serve to prevent the direct entrance of the water into the furnace casing and ensures
the heating thereof up to the moment when, with diminished specific gravity, it
rises to the edge of the said trumpet mouths. Thus it enters the furnace casing
with its temperature already raised.
The circulation of the flame and of the water will take place as follows:-Let it
be supposed that the level in the upper reservoir and in the boiler is determined. At
the moment when the fire is lighted, the flame, after having spread in the furnace,
enters the large boiler tubes from their rear extremities; it passes to one side of the
boiler, and extends to the other extremity thereof; then arriving at a vertical
partition, it rises and turns in descending, thus lapping one entire exterior side of
the reservoir and furnace. Then passing above the furnace at the other side, it
re-ascends and pursues its course in the opposite direction to the end of the boiler,
where it enters the passage which conducts the products of combustion to the
chimney.
As soon as the action of the heat commences, the water surrounding the furnace
becomes heated; it rises and is replaced by the cold water descending from the
reservoir. Thus a rapid circulation around the furnace is created.
As soon as any
steam is produced, it flies to the reservoir by the shortest way, that is to say, by the
trumpet-mouthed tubes; and when once this action is established at the normal
working pressure, the circulation continues and increases in rapidity, according to
the activity of the vaporization or generation of steam.
To accelerate and regulate the circulation, I employ diaphragms or partitions
which separate the ascending from the descending currents.
The upper reservoir also serves as a dejector for all the deposits. The feed water
remains therein long enough for its temperature to be raised to a degree at which
all its calcareous deposits will be formed, and all muddy sediment will be deposited,
so that the boiler will be fed with water purified from chalky and muddy deposits.
A cleansing tube is arranged at the bottom of the said reservoir for discharging
these deposits by means of a syphon.
An auxiliary feed tube is provided in case the feed apparatus should be deranged.
This feed tube is connected with the aforesaid water tube, and is controlled by a
three-way cock.
As above stated, the combustion of the coal is aided by a special supply of air.
There is an air chest, on leaving which the air is heated by contact with the products
of combustion in the tubes and passes to the grate through suitable openings And
by other apertures the air is conducted into hollow pieces of refractory material,
which are perforated and assist the heating of the products of combustion. And to

page_text: prevent the action of the flame upon the plates not covered with water, I provide a
refractory mask or shield between the fire-place and the front of the boiler.
I will now describe various modifications of this Invention, whereby it is adapted
to other than Cornish boilers.
For heating the air which is destined to consume the gases, I make use of the
heat radiated by the walls of the furnace, and create thus a heating with recuperated
heat, and in order better to utilize the heat given off by the furnace, the liquid
mass is divided into several bodies, and the boiler tubes are formed of sets of metal
tubes of small diameter with a view to diminish the space occupied for a given
power, and to reduce the cost of the apparatus.
The heating is effected in such a manner that the circulation of the heated gases
is produced in a contrary direction to that of the arrival of the water in the various
parts of the boiler, of which the water and steam communications are effected by
exterior pipes. These arrangements also facilitate the flow of the steam and circu-
lation of water throughout the whole apparatus.
It is to be understood that this Invention relates partly to the combination of the
above features for the purpose of obtaining a better result than it has been hitherto
possible to obtain with the boilers now in use.
In order to utilize the lost heat by the radiation of the lateral and upper walls of
the furnace, I provide within the substance of these walls channels, formed either
by the bricks of the furnace or by layers of hollow bricks, these channels being
divided in such a manner that the exterior air may penetrate therein, either at the
front or back of the furnace, or on both sides at once. This air circulating in a
perfectly divided state through these narrow channels, which form a true hot air
apparatus, becomes heated and absorbs the heat radiated from the whole extent of
the walls, which heat is lost and wasted in ordinary arrangements, escaping into
the atmosphere and surrounding materials.
The section of the side holes provided to admit the air is calculated to permit the
passage of the necessary quantity to burn all the gaseous part of the fuel; these
side holes are provided with registers to regulate the admission of air at will."
The currents of air on emerging from the said channels all unite in a chamber
provided in each of the cheeks of the furnace, and are, as will be easily understood,
heated methodically. This hot air is then injected through a great number of holes,
either behind the bridge and laterally through three tubes combined in horse-shoe
form to produce a stirring or agitation of the gases, and to determine their intimate
mixing, or all around the furnace where the same effects are produced. I may
employ either of these devices according to the more or less gaseous nature of the
fuel.
According to one arrangement the air penetrates at the front of the furnace
through openings, and at the back through other openings, and circulates under the
whole extent of the upper and lateral walls of the masonry enveloping the boiler;
then the currents of heated air unite in the two chambers provided in the cheeks of
the furnace, going thence to the distributor formed by perforated tubes, which
send it into the middle of the gaseous mass produced by the combustible material
upon the bars.
I have thus shewn how the first object of this Invention is obtained, that is to
say, the heat radiated by the walls is utilized for heating the air, which heat would
otherwise be lost, and it is thus restored to the apparatus.
The greater the distance from the furnace, which is the place of combustion, the
greater is the decrease in the intensity of the hot gases; therefore, in order to get
from them all the effect possible, it is necessary to divide the mass which is to be
heated in order to present it in the most favorable condition for the absorption of
caloric. For this purpose I employ multitubular boilers.
In all cases where the available space will permit it I arrange the tubes of the
said boilers in horse-shoe form, so as to reserve between these tubes & free space
sufficient to allow facility for cleaning, to prevent the deposit of soot, and to spread

page_text: the said tubes in the elevated zones of the flues where the gases are at a higher
temperature.
The multitubular boiler tubes are united one to another and to the upper shell
by means of communications exterior to the furnace, and arranged at the back of
the latter, and by means of horizontal communications, which allow the circulation
of the water to take place in exactly a contrary direction to the current of smoke
circulating in the channels of the furnace.
The upper shell of the boiler and the two inclined lateral shells, which are equally
inclined for facilitating the circulation of the water and steam, communicate by
means of vertical pipes with a horizontal shell placed above the furnace, and forming
a reservoir of steam.
In one arrangement the circulation of the smoke is effected inside the different
parts of the boiler, the shell of which is provided with tubes similar to those of the
well-known "Field" boiler, and has interior water spaces for ensuring the circula-
tion of the water in the apparatus.
The smoke pipe passes into a lateral heating tube, and traverses a lower water
receptacle, from which the injector takes its supply, the said injector driving the
water into a bottle-shaped supply vessel placed near the lateral heater, which has
upon it the safety apparatus, and with which it communicates at its upper and
lower part.
The furnace of the boiler, as in the previously described arrangement, is provided
with orifices for the supply of the air necessary for combustion, only this air is not
heated except by the waste heat from the smoke pipe after it leaves the water
supply receptacle.
In a further modification of this Invention the circulation of the smoke takes
place in the interior of the different parts of the boiler, whose shell is provided with
tubes, as in the aforesaid "Field " boiler, and has interior water spaces designed to
ensure the circulation of the water in the apparatus. A smoke pipe of channel
passes then into a lateral heating tube, and through a lower water receptacle, from
which is supplied an injector that drives back the water in a vessel placed near
the lateral heater, upon which are the safety apparatus, and with which it commu-
nicates at its upper and lower part.
The furnace of the boiler, as herein-before described, is provided with orifices for
the supply of the air necessary for combustion, but the air is not heated except by
the waste heat from the aforesaid smoke pipe or channel.
The furnace, forming the basement of the boiler, comprises the following parts,
that is to say-An air chest, into which the air is injected, either by a ventilator,
or by the well-known "Koerting" air injector, an ash-pit, a grating, flues conducting
the air above the grating by a series of jets to the fuel, and a feeding apparatus.
The boiler is formed of a central piece, having at the bottom an inclined boiler
tube, and at the top a series of the well-known " Perkins" tubes, exposed directly to
the flames. An obturator forces the flames to play upon these tubes. The products
of combustion pass away by a bent tube to a chimney, passing on their way, first,
over a serpentine steam superheater; and, secondly, through a supply vessel and an
open cistern.
The furnace is surrounded by a cylindrical diaphragm. Near the said vessel is
another vessel, which I call a safety vessel, communicating at the top with the said
supply vessel and with the boiler by the bottom tube. The said supply vessel
communicates also with the boiler by a tube, and the communications may be con-
trolled or shut off at will by means of cocks provided for this purpose.
The pipes have their outlet in an injector of annular form, from whence the
water flows after having remained therein a certain time and become heated.
A bottle-shaped vessel communicates with the boiler above and below the level
of the water by two tubes. It has a float, the stem of which shuts or opens the
upper orifice united by a pipe above the said vessel.
The boiler has removable joints, and a special arrangement prevents the door of

page_text: the furnace from being opened without closing at the same time a register at the
bottom.
The combustion is regulated by an upper register, which is worked by hand.
In adapting the so-called "Perkins" tubes to the purposes of this Invention I so
5 arrange them that the descending water is completely separated from the steam
being generated by taking the water laterally in such manner that all conflict between
the water and the steam is obviated.