Improvements in and in connection with Apparatus for Producing Steam at a Low Pressure.
Year: 1892

page_text: Date of Application, 24th Dec., 1892-Accepted, 18th Nov., 1893
ענעע JUI
DIEVITTUALION.
Improvements in and in connection with Apparatus for Producing
Steam at a Low Pressure.
1, CHARLES BOURDON, of 26 Boulevard Magenta, Paris in the Republic of
France, Civil Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention has for its object an apparatus for producing low pressure
steam.
On the accompanying drawings:-
:―
Figure 1 shows an apparatus suitable for a small production:
Figures 2 and 3 show an apparatus for a larger production, the form alone
differs, the principle remains the same. This principle consists in having, in contact
with the furnace, only the smallest possible quantity of water in order to rapidly
produce the steam which is required, and in separating this quantity of water from
that which is employed for feeding the boiler. This feeding is performed con-
tinuously by placing the chamber where the steam is produced in communication
with a feed water reservoir, and then in supplying this feed water cistern by
means of a ball cock arranged on a suitable water pipe, or by any other suitable
means.
The apparatus for producing a small quantity of steam, shown in Figure 1, is
composed of a furnace, having a continuous feed, closed at its upper part by a lid,
and terminated at its lower part by a grating. The products of combustion escape
by an anuular chamber B and pass into a chimney C.
The steam is produced in the annular chamber D, in direct contact with the heat
of the furnace, and is discharged by a side tube E..
The feed water reservoir is placed at F, in an annular chamber insulated from
that in which the steam is produced by an air chamber G, which may be filled, if
necessary, by any suitable insulating material. This reservoir communicates at its
lower part H by means of a space arranged between the walls with the chamber
where the steam is produced.
Finally an automatic feeding apparatus, formed by a ball cock arranged on a
water pipe is shown on the drawings at I.
The outer wall a of the chamber where the steam is produced, the bottom piece b
of the insulating air chamber, the internal partition c of the feed water reservoir,
and the cover d of this reservoir, form a complete apparatus which may be taken
down in one operation allowing this part to be easily cleaned in case the feed water
contains salts or mud. The only joint which requires to be made in this mode of
construction, is the one which connects the outer wall a of the chamber where the
steam is produced with the upper part e of the internal partition f.
If it be desired that an apparatus of this kind shall allow of a varying pro-
duction, a series of one, two, three or more furnaces each provided with an
insulating chamber (G) may be placed side by side in a single feed reservoir F
and according to the production of steam required 1, 23 or more of the furnaces
may be lighted.
It may be necessary, in certain applications of this boiler, to produce steam at a
very low pressure. For this object and in order to limit this pressure the steam
discharge pipe E may have a branch J which is immersed in the feed water to a
certain depth. In certain cases, the steam after having served for the purpose for
which it is intended, is condensed, and the water of condensation may be returned
if desired, by a pipe K into the feed cistern. This pipe is immersed in the water

page_text: in this cistern, in such a way as to condense (until the water in the cistern reaches
100 degrees) the small quantity of steam which may return by this pipe. The
difference of level betweeen the mouth of this return water pipe K and the bottom
of the branch pipe J determines the maximum pressure available for producing the
circulation of the steam. This production at a very low pressure makes it
unnecessary to prevent the water in the boiler from communicating directly with
the atmospheric air; either by the lid d not being tight fitting, or by its being
provided with a pipe allowing communication with the open air, or by the feed
cistern I.
In any case, it is preferable that the return water pipe K shall not be directly
inserted in the reservoir of the vapouriser, because that would cause inconvenience.
In fact when the fire of the apparatus was put out, the water from the reservoir,
under the action of the vacuum which would be produced by condensation in the
pipes and the stoves, would be drawn up both by the return pipe as well as by the
pipe J, and would fill all the heating apparatus, seeing that the ball cock would
continue to feed it. This drawback is avoided by causing the pipe K to open into
a siphon as is shown in Figure 1 of the drawings. When the fire is put out, the
water of this siphon only is absorbed, and then the external air rushes in,
disconnects the siphon, and prevents a vacuum being formed. This arrangement
further allows of a small pressure being created in the pipes which maintains a
good distribution of the heat.
It is needless to state that the siphon may be made in the form shown on the
drawings, or may have the usual curved shape.
It will be seen thus that this boiler does not present any danger, seeing that,
in case there should be any stoppage in the discharge pipe in consequence of the
closing of the tap, or by any other reason, the steam produced in the chamber D
will be discharged by the pipe J as soon as it shall have attained a pressure,
the limit of which is fixed by the distance this tube is immersed in the feed
cistern.
Finally, two methods of regulating the working of this apparatus are shown on
the drawings.
If the steam be produced by the apparatus in. a greater quantity than is required,
the return water pipe K, in place of returning water to the boiler, will return
there the steam produced in excess. This steam is discharged in the form of damp
vapour, and will serve for regulating the apparatus by diminishing the draught of
the furnace, and consequently the production of the steam.
The first means of regulating consists in discharging this damp vapour. by means
of a tube L which opens into a valve chamber' M. A very sensitive valve is keyed
on the same spindle as the chimney valve N. This latter is counterbalanced in such
a way as to remain, when once let go, in a position to open the draught.
The watery vapour reaches the valve M and causes it to assume, in consequence
of the pressure, although the latter is small, which it has, an inclined position
which causes a
partial or total closing of the chimney valve and, consequently,
a diminution of the activity of the furnace and of the production of steam. The
watery vapour which proceeds from the valve chamber M is discharged into the
atmosphere.
The second method consists is conducting the watery vapour which is released by
a tube L' under the grating of the furnace by means of a pipe O. The air,
consequently, arrives in small quantities under the furnace, and, arresting the
combustion, diminishes the production of steam.
The action of this jet is the more efficacious in that it acts not only by rendering
the air less combustible but by diminishing the facility of its access to the grate,
when care is taken to direct it towards the door of the ash pan by a suitable device
at a suitable pressure.
These two methods of regulating herein before described act equally in the case
where an excess pressure is produced in the chamber D, seeing that the steam which
then escapes by the tube J, as has been hereinbefore explained, escapes from the

page_text: apparatus by the tube for discharging the water vapour L or L' acting with
regulating apparatus, or directly on the furnace to check the fire.
This excess of pressure may be caused by the apparatus, owing to the
application which is made of it, having a tap on the tube E, which may be
closed at will.
When it is desired to produce a large quantity of steam, with the apparatus
working ou the principle hereinbefore described, it is preferable to separate the
vapouriser from the feed.
The apparatus for producing large quantities may then be arranged as is shown
in Figures 2 and 3 of the accompanying drawings. It is composed of a furnace A
continuously charged, closed by a cover B and terminated at its lower part by a
grate C and an ash-pan G. A door F serves for firing the furnace. The fuel is
sustained by a bridge H. The combustion is produced in a chamber D completely
surrounded with water; this water is contained in the boiler, properly so called, and
circulates within the walls N, O, P, Q, connected one with another by a group of
tubes I, and in a partition K communicating at J with the side walls of the boiler.
The combustion gases pass by the flues L and reach the chimney M. The boiler
is surmounted by a dome R, whence the steam produced escapes by means of a
tube S.
The construction is such that the charger A, the furnace, the partition K and the
wall O, the group of tubes I and the internal walls gij of the boiler, may be
withdrawn at a single operation, which ensures an easy cleaning and necessitates
only a single joint at 1 being employed for the boiler.
The feed water reservoir is situated at T; the water runs into it by means of a
ball cock U and passes into the lower part of the boiler by a pipe X having a
branch orifice f.
In order to ensure a certain pressure, but always a low one for the steam, thus
allowing it to be used for certain purposes, the discharge tube S is prolonged on
one side by a tube V which is inserted into the feed cistern, and in the tube X,
which places this cistern in communication with the boiler. The pressure of the
steam will be therefore determined by the difference of level between the water of
the feed cistern and the lower opening of this tube V; the water of the boiler is
nevertheless in communication with the external air by means of the tube X, which
communicates with the open air, either at its upper part or by means of a tube
starting from the orifice and passing under the regulating bell Z, of which mention
will be made further on.
According to the usages and the pressure of steam which it is desired to
obtain, the dome R, the tube X and the tube V must be of a suitable height.
The water of condensation from the apparatus which utilise the steam may
be caused to return, if desired, to the feed water reservoir by means of the
tube Y.
The mode employed for regulating the boiler is shown on the drawing.
It may be applied to the type of boiler for a small production, which has already
been described and the means employed for that type may also be employed for the
boiler for a large production which is now being described.
This system of regulating also utilises the steam produced in excess in case of a
too great production of the boiler. This steam comes by the tube for returning the
water Y, and lifts a bell Z, which is immersed in the water of the feed reservoir,
if it be not desirable for this steam to come in contact with a large surface
of water, which might condense it, and diminish the delicacy of the regulating ;
this movable bell Z may slide over a fixed bell, however, this fixed bell is not
indispensable.
-
A triangular slot r is arranged at the base of the movable bell Z in such a way
that the first quantities of steam may arrive under the bell and escape therefrom
by this slot, without acting suddenly on the regulating levers.
It is only when this quantity of steam becomes a considerable one that the
movable bell Z is raised by the force of the steam which passes between it and the

page_text: fixed bell, and acts by the levers a and b on the valve of the chimney, which
diminishes or totally arrests the draught. The bell, in rising, uncovers a gradually
larger portion of the triangular slot and allows the steam to partially escape by
this slot, which further avoids any too sudden effect or too sudden action of the
bell on the regulating levers.
If the quantity of steam produced is too much to be carried off by all the
steam using apparatus and to reach the tube Y sufficiently in time to regulate the
draught, or if, by any cause whatever, the discharge pipe for the steam S is
stopped, the steam produced passes by the tube V and is discharged into the open
air where it may go through a suitable vent, and be condensed in the feed tank.
The damp steam escapes by a tube m. No danger of explosion is, therefore, to
be feared, the steam produced being able to escape into the open air...
In Figure 7, is shown an apparatus composed of a fire-place A having an
inclined grate with a charging apparatus B, formed by a hopper containing the
reserve of fuel. This grate is surrounded by the boiler C, properly so called,
where the water in a thin layer rapidly comes to the boil. The products of
combustion escape by two side openings D, arranged in the double wall of the
boiler C. They are brought by the side flues E, having internal baffle plates F,
up to the chimney G. This latter encloses the steam dome H, which surmounts
the boiler G. The feed water reservoir is at I; this water can never be brought
to boiling point, for it only receives the heat of the products of combustion which
are relatively cool.
:
In proportion as the water is very rapidly evaporated in the boiler C, it is
replaced by water from the reservoir, which passes by the tube J into the
boiler C. Its construction is such that the furnace is completely independent of
the rest of the apparatus. This part being the only one which can become worn
out, it may be replaced, whilst preserving intact the feed water reservoir and
the fuel hopper.
The plate K behind the boiler being removable, all the parts in which the
evaporation is produced may be easily cleaned.
The second type, of a more simple construction than the preceding one, is
shown in Figure 6.
The boiler, properly so called, is formed of a circular grating A placed at the
bottom of a central furnace B, one portion of which is occupied by the
chimney E.
The water exposed to the action of the furnace is in a circular portion F of
relatively very small thickness.
.
A circular air chamber G insulates the boiler from the feed water reservoir H
which communicates with the latter by the annular space I. A rod D, projecting
from the ash-pan, allows the grating A to be rocked.
The boiler F is of a greater height than the feed water reservoir H so as to
form the steam dome L at its upper part. On this steam dome, the pipe for
conveying the steam J is arranged. The feed water may be introduced by means
of an opening situated in the upper part of the reservoir H. In order to
internally clean the apparatus, the air chamber is removed in a single piece, and
the upper lid of the apparatus. The part comprised between the furnace and the
external case is accessible from all parts after this has been done.
The quantity of steam produced may be regulated in both these types of boilers
by regulating the draught of the furnace by a valve placed in the smoke stack.
The systems of automatic regulation described for the preceding vapourisers may
be applied to one or other of the types of boiler which have just been described.
.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, 1 declare, that what
I claim is
1. In an apparatus for producing steam of low pressure, forming in the boiler
two parts of very unequal volume separated by an air chamber, a layer of insulating

page_text: material, or even quite apart from one another in such a way as only to subject to the
action of the furnace the very smallest quantity of water possible, so as to create
a rapid evaporation, whilst the part of the boiler which forms the feed water
reservoir always remains in communication with the air in the manner and for the
object stated.
2. The means hereinbefore described for limiting the pressure in the pipes of
the heating apparatus, as well as the siphon arrangement employed for returning
the condensed water into the boiler whilst preventing, when the fire has been
extinguished, water from filling the apparatus where the vacuum is formed.
3. The system of automatic regulation by means of a valve or by means of a
movable bell acting on the damper of the chimney and in certain cases by the
introduction of steam under the fire place, substantially as herein before described
and with reference to the accompanying drawings.
4. The mode of construction of the vapouriser having only very few joints, thus
allowing of its being taken down and its parts being easily and rapidly cleaned
substantially as herein before described and with reference to the accompanying
drawings.
5. The arrangements and the construction of vapourisers substantially as
hereinbefore described and with reference to Figures 6 and 7 of the accompanying
drawings.
6. The general construction and arrangement of apparatus or devices substan-
tially as hereinbefore described and shown in the various figures and for the
purposes specified.
Dated this 23rd day of December 1892.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.