Improvements in Low Pressure Boilers or Water Heaters.
Year: 1894

page_text: Date of Application, 30th May, 1894-Accepted, 29th Sept.,
1894
CUMI LEID DI BUITRATIVA.
Improvements in Low Pressure Boilers or Water Heaters.
I, CHARLES BOURDON of 26 Boulevard Magenta, Paris, in the Republic of
France, 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 improved generators or vaporisers for producing
a considerable quantity of steam at a low pressure for heating houses, vehicles and
the like.
These apparatuses are distinguished not only by the small space which they
occupy and the simplicity of their construction, but also by their safety when being
used, for they are furnished with arrangements which regulate in an automatic and
certain manner the quantity of steam produced.
On the accompanying drawings-
Figures 1, 2 and 3 show one of the arrangements which may be employed.
This vaporiser is composed of a special vessel of sheet or cast metal A formed
of parallel strips leaving an alternate passage for the water by the interstices bbb
These
and passage for the products of combustion by the interstices a a a.
interstices a a a all communicate with a vessel A' which forms a combustion
chamber in which a grate D fed by a hopper B, provided with an oscillating
door C, is situated.
The products of combustion, after having passed through the interstices a a,
unite at E and from there escape by the chimney F.
The part A is surrounded by a casing G containing the water which is to be
converted into steam by its circulation through the interstices bb, of which mention
has already been made. The water may surround the part A not only on its three
faces as Figures 1 and 2 indicate, but also on the fourth side of the front, that is
on the side where the hopper is. The steam produced in the interstices bb is
collected in a dome H from whence it is distributed by means of pipes I.
The two parts A and G are therefore fitted the one in the other and are
connected together by a bolted joint on the circumference of their front face. This
capability of removing the furnace renders the cleaning of the boiler very easy
and therefore its repairs and lasting power are thus ensured. The pressure at
which the steam is produced may be regulated by the following arrangement.
The steam dome H communicates by means of a tube J (the so called manometric
tube) with a vessel K filled in its lower part with liquid, the nature of which varies
according to the pressure which it is desired to obtain. This liquid is water for
low pressures, mercury and other suitable liquids of great density when it is
desired to obtain greater pressures. This safety device very particularly
characterises my apparatus but without assuming too great importance. The
adjustment of levels produced by the steam being brought into the tube J causes
the liquid in the vessel K to rise, and the difference of beight between the level of
the liquid in the tube J and that in the vessel K gives the pressure of steam at
which the apparatus works. If the production of steam exceeds the consump-
tion, or if the pressure rises in consequence of the excess of production this excess
of pressure escapes through the liquid, and is discharged into the atmosphere by
the escape tube M. This accessory of the vaporiser thus serves as a safety valve,
seeing that as it communicates with the atmosphere, it avoids any excess of pressure
of the steam produced by the vaporiser. The liquid of the vessel K is covered
with a certain depth of water due to condensation. This water may escape by the
overflow tube L, which, if placed high enough, may return the water to the boiler.

page_text: '
In order to prevent the liquid being ejected by an excess of pressure or sudden
increase in the production taking place, a piece of sheet metal m placed at the
mouth of the escape tube M in the vessel K prevents the liquid being carried into
this tube, any such conveyance of the liquid into the tube being rendered more
difficult by reason of the upper part of the vessel K being widened out. This
manometric vessel has therefore the great advantage of always limiting the
pressure without ever causing loss of the liquid, measuring this pressure, by an
overflowing to the outside.
The escape of the excess of steam by the escape tube M may be utilised in order
to regulate automatically the working of the apparatus, by acting on the draught
of the furnace itself. For this purpose, the steam which is released by the escape
tuhe M passes through a box N placed on this tube. In the interior of this box
there is a tube O elliptical in section, coiled in a spiral and filled with liquid. Under
the action of the heat at the moment when the steam escapes by this tube M, the
expansion causes a movement of one end of this tube, the other end being fixed.
This movement is communicated by a rod P actuating the damper of the
chimney. If, therefore, the apparatus produces at a given moment an excess of
steam, the latter on being released by the escape tube M passes through the box N
and warms the pyrometer O. The expansion of this part O operates the valve Q
which then diminishes or damps the draught of the chimney, and consequently the
speed of the fire, and thus diminishes the production of steam. There is thus
obtained an automatic regulation of the working of the apparatus. A valve,
adjustable by hand, allows of the fire being regulated to a suitable extent at the
commencement, and it is only when an excess of production is caused that the valve
of the regulator intervenes to moderate the fire. The water of condensation
arising from the heating apparatus returns into the vaporiser by the tube Y
(Figure 3), but, in order to compensate for the loss of water due to the escape
from the escape tube, it is necessary that the apparatus should be able to be fed
automatically. For this purpose, a tightly closed reservoir V (Figure 3) com-
municates, on the one hand, with the water in the boiler by the tube X, and on the
other hand, with the steam of the dome H by the passage W. The level of the
water in this reservoir V is therefore maintained at the same height as that in
the boiler. A hinged float U follows the variations of this level of water. If this
latter drops, and it is thus necessary to feed the boiler, the float, in sinking, acts
by means of a chain Z on a tap S, supplying water to a reservoir R placed at a
height a little above the height of the column of water representing the maximum
of pressure to which the vaporiser is to work, and which is regulated by the
manometer tube. The reservoir R communicates with the vessel V by means of a
pipe T, through which the chain Z passes.
By this arrangement, it will be seen that the float tap is worked without even
passing through a stuffing box, being placed outside, and may be inspected at any
moment. As to the float itself, it may be placed either in the boiler or in a special
reservoir as described.
Figures 4 and 5 show two modifications of the arrangement of the details herein-
before described, the one relating to the automatic regulating of the working, and
the other to a method of feeding the boiler. As I have already stated, an excess
of production of steam is shown by an excess of pressure, which is limited by the
manometric tube. This safety apparatus may be composed as follows, and is shown
in Figures 4 and 5 :—
The steam dome is connected by a tube J' with a vessel K' divided into two
parts by a vertical partition 1. The liquid which is at the bottom of this apparatus
rises in the vessel K on the side of the partition 1, opposite to that where the
tube Jenters, and the variations in the level of the liquid in this side of the
vessel K' follow either those of the production, or those of the pressure itself. By
means of a float N¹, these variations are transmitted by a rod B¹ to the draught
valve, or damper, Q. The end of this rod acts on the lever P, operating the valve
by means of a trunnion, which works in a slot in such a way that the float only

page_text: causes the closing when the apparatus is on the point of exceeding the pressure,
that is to say, the limit at which the vaporiser is to work. A cap which prevents
the ejection of the liquid in the case of a sudden excessive production of steam, is
also arranged at m'. The escape tube M is placed on top of the vessel K¹, and
tbus ensures communication with the atmosphere and prevents any dangerous
excess of pressure. The regulation of the working of the apparatus is thus ensured
by this arrangement. The feed may also be provided in a different manner to the
one I have already herein before described. If working at a pressure of several
metres of water, it is desired to avoid the choking of the tube T (Figure 3) at one
end of which is the feed tap.
A vessel V is arranged communicating on the one hand with the water of the
boiler by a pipe X and on the other hand with the steam dome H by the pipe W.
In this vessel V1 where the water keeps at the same level as that in the boiler,
there is a float r¹ acting by a hinged rod projecting from this vessel V₁ provided
with a tight joint on the tap for supplying the water S', the pipe of which is
connected with the vessel V1. When the level drops, the float opens the tap
which may then discharge into the vessel V', the water intended for feeding the
boiler, which water being supplied at a pressure greater than that which exists in
the boiler, can penetrate therein. The type of vaporiser which I have just
described, comes under the category of vertical boilers. It has, therefore, the
advantage of being able to be placed in very small space, but if it be desired that it
should have a great heating surface, its height and consequently the level at which
the water stands when there is no pressure are considerably raised above the level
of the ground.
This causes great inconvenience where my vaporiser is employed for heating
rooms, apartments, etcetera. In this case, in fact, the steam generator is placed in
a room which is at the same level as those which it is intended to heat; it is then
necessary (in order that the return of the water may be effected at whatever
pressure the apparatus may be working) to place the bottom of the condensing
surfaces at the height of the highest level which the water can occupy in the
vaporiser. I had, therefore, to design an arrangement of my apparatus with a
horizontal heating surface allowing great evaporating power to be obtained with a
generator of small height.
In this new combination, which is shown in Figures 6 and 7, I have endeavoured
to preserve the working with a continuous firing which alone can yield a regular
heating, as well as a furnace which is easily accessible, which I consider as
indispensable for ensuring the good maintenance of a generator with a small
quantity of water.
This vaporiser is composed firstly of a vessel A formed of two chambers, one
vertical a, the other horizontal rivetted together. The vertical face C of the
part a is not closed and it is provided on all its periphery with an angle
iron d, so that a second vessel B may be always fitted into the vessel A
(the vessel B having exactly the same form, but smaller dimensions) in
such a way that there remains a larger or smaller free space between the two,
according as it may be desired to have a generator containing a greater or less
volume of water. The parts A and B are connected by a series of bolts, forming a
joint, on one side with the angle iron d and on the other side with the angle
irons e el in the form of a square which are rivetted to the extremities of the
vessels. The boiler with an accessible furnace is thus constructed. The
interior of the chamber a¹ of the part B is utilised for forming the furnace, and
that of the chamber is either a boiler tube or group of tubes, or a passage or pipe
of suitable form for giving a greater or less heating surface.
The furnace is closed along the face C by a sheet or cast metal plate which
is bolted on the part a' and in which openings f g h are formed, serving respec-
tively for charging with fuel, for arranging it on the grate and for removing
the cinders. If it is desired to keep the fire continuously going, this furnace is
made of great height and a charging hopper D is arranged inside of the same

page_text: form as the chamber a' but of smaller dimensions, thus providing an intervening
space as a passage for the products of combustion in order to convey them to
the boiler tube ¹. This charging hopper is not rivetted except at the front C
in order that it may be replaced by only unfastening this part. The drawing
shows that this hopper is not only arranged parallel to three sides of the
chamber A¹ but also on the front side C in order to protect this plate from
the direct action of the fire, and to prevent it from warping. The grate and
ash pan may be of any suitable construction. At the end of the boiler tube b'
there is a smoke box E which supports the chimney F.
When it is desired to work at a pressure of several metres of water with a
constant level, the methods of feeding and regulating the pressure and the
regulators which I have hereinbefore described and which are shown in Figures 3,
4 and 5, are employed. The height of the water is thus regulated by means of a
float placed in the vaporiser or in a special vessel which operates the tap outside.
If it is desired to work at a low pressure, that is to say, at less than one metre of
water, it is generally more advantageous to employ the arrangement shown on the
drawing in Figure 6. I place over the boiler tube 6 of the vaporiser or on any
other suitable place a feed tank G which I connect with the boiler b by means of a
tube K which always remains open. In this same tank, the level of which may be
maintained at a constant height by means of a float, I cause a pipe L which is
connected with the boiler in front of the tap which carries off the steam, if there
be one, to be immersed; this tube is the one which I have called the manometric
tube or the regulating pressure tube. It is of sufficient section to allow the excess
of steam produced to escape to the outside, which steam heats the water contained
in the tank G until it reaches the boiling point, and the surplus steam is then
discharged into the atmosphere by the tube m. This mode of working is also the
one which I have described herein before, and which characterises very clearly my
apparatus. It will be seen that when the vaporizer shown in Figure 6 works in the
manner in which I have just explained, the level of the water contained in the
vertical part of the chambers a a¹ lowers in proportion as the pressure rises, and as
the water is forced back at this moment into the tank G by the tube K. But it
must be noted that the immersion of the manometric tube, as I have hereinbefore
stated limits the pressure, and at the same time the lowering of the level of the
water which is produced in the vaporizer. If care therefore, be taken to place the
upper part of the tank at the height of this level, (which is the lowest which can
be produced) the gases of the furnace can never come in contact with the walls of
the furnace behind which there is no water. This fresh arrangement of my
vaporizer, brings therefore the products of combustion in contact with the heating
surface, which may be extended as desired, and completely cooled by the water.
It will be seen besides, that as I have hereinbefore stated, with this type of
vaporizer the highest level which the water can occupy is relatively at a short
distance from the ground, although the apparatus may have great evaporating
power. This is, as already stated, very advantageous for heating rooms.
When it is desired to avoid having a smoke box at the rear of the boiler, with
the inspection door such as already described, and which may be an inconvenience
in attending to the apparatus, a special construction of vaporiser shown on Figure 8
of the accompanying drawings may be employed. The vaporiser, properly so
called, is composed, as I have just stated for the preceding arrangement, of two
similar chambers A and B fitted one in the other. The products of combustion,
instead of escaping at the rear into the chimney, return in the reverse direction
(as in boilers with return flues) owing to a water tube C placed in the horizontal
part of the body D of the boiler. They then pass into a passage or tube placed
between the charging hopper E and the boiler in order to finally escape into
the chimney.
The charging hopper has its charging opening placed on the front, as in the
preceding figure, and it is constructed in two parts, the lower one F of which is
directly exposed to the fire, and consequently is liable to need more frequent

page_text: repairs, may oscillate on a hinge on the double wall. A series of hooks holds this:
part in place when the apparatus is at work and forms a joint with the front.
The furnace, the grate and in general all the accessory parts of this apparatus are.
similar to those hereinbefore described.
One advantage of the removability of the lower part of the furnace is the facility
for sweeping.
When it is lowered, access may in fact be easily obtained above and below the
boiler tube, and thus the soot which may have been deposited in the smoke box
may be easily and conveniently removed. Flat or cylindrical forms may be-
employed for the construction of these two last described types of vaporisers, 'or
the horizontal body as well as for the vertical body, the first form being suitable.
for low pressures, and the second for those which exceed 1 metres of water. The
manometric tube instead of being immersed in the feed tank may be placed
externally, as shown, in the type of the vaporiser represented in Figure 9. The
lower end of this tube p, qr stands at the lowest point which the level of the
water in the apparatus must be at when the pressure which it is not desired to
exceed is attained.
Another and even simpler arrangement consists in employing the feed tube as a
manometric tube. It is sufficient in fact to make this tube of a sufficiently large
section to allow at the same time the water and the steam to pass, and to bore in
this tube a hole such as S (Figure 9) at the level which the water assumes in the
vaporiser when the maximum of pressure is attained. The feed tube may also.
be caused to end at the height of this level as is shown at tu, Figure 10.
The various arrangements of vaporisers which I have described hereinbefore,
show that the construction of this apparatus may vary to any extent. Con-
sequently, in addition to the arrangements which I have herein before described,
I desire to claim as my invention the method of working which is shown in.
all the drawings which I have annexed, and which is applicable to any type
of boiler whatever.
I have always presumed that all these apparatuses are employed for producing
steam, but I also reserve for myself their use as hot water boilers, applicable
for thermo-syphons, or other like apparatus. The low pressure steam generators,.
which I have just described, are applicable for heating rooms and other places,.
as well as for heating vehicles..
Having now particularly described and ascertained the nature of my said inven--
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. An apparatus or generator for producing low pressure steam, consisting of a.
part A of parallel strips or divisions producing separate and adjacent passages a.
and for water and the gases of combustion, a removable furnace B having a.
charging hopper and oscillating door C, a casing G containing the water to be:
evaporated and a steam dome H substantially as hereinbefore described and shown.
in Figures 1, 2 and 3 of the accompanying drawings.
2. In a low pressure steam boiler, the use of a pressure regulator formed of a.
manometric tube J, immersed in the vessel K, which contains a liquid (such as.
water, mercury or the like,) the density of which varies with the pressure which
it is desired to obtain; this vessel K being further provided with an overflow
tube L for the water of condensation, together with a screen m for preventing the
liquid being forced out, and a tube M for allowing the excess steam to escape into.
the open air, substantially as hereinbefore described and shown.
3. In a low pressure steam boiler, the automatic regulation of the draught of the
furnace by means of a pyrometer O arranged in the box N in the steam escape
pipe or passage and connected by means of the rod P with the valve or damper Q
of the chimney; substantially as described and shown.
4. In a low pressure steam boiler, the automatic supply by means of an external
reservoir V communicating by the tube X with the water in the boiler, and by

page_text: the pipe W with the steam dome, in combination with the float U, the water
supply pipe T, the feed tap S and the operating chain and connections Z; sub-
stantially as hereinbefore described and shown more particularly. in Figure 3 of
the accompanying drawings.
5. In a low pressure steam boiler or vaporiser, the automatic regulation of the
working of the apparatus by means of a manometric siphon tube J¹ K', provided
with a screen m² and an escape tube M, in combination with a float N' actuating,
by means of the rods B₁ P₁, the draught valve Q in the manner and with the
object hereinbefore indicated, and with reference to Figures 4 and 5 of the
accompanying drawings.
6. A low pressure vaporiser of horizontal pattern, in combination with a
manometric tube plunging into the water of the feed reservoir, substantially as
herein before described with reference to Figures 7 and 8 of the accompanying
drawings.
7. In a low pressure vaporiser, the arrangement of a manometric tube p q r,
placed on the outside, the lower end of which terminates in the feed tube at the
lowest point occupied by the level of the water in the apparatus; substantially
as hereinbefore described and with reference to Figure of the accompanying
drawings.
8. In a low pressure vaporiser, the use, as a manometric tube, of the feed
tube itself placed in communication with the boiler at the lowest point of the
water level, either by means of an opening s, Figure 9, or by a tube t u, Figure 10,
substantially as described and shown.
Dated this 20th day of May 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.

page_text: Date of Application, 30th May, 1894-Accepted, 16th Mar., 1895
COMPLETE SPECIFICATION.
Improvements in Heating and Ventilating Vehicles.
I, CHARLES BOURDON of 26, Boulevard Magenta, Paris in the Republic of
France, 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:-
The system of heating hereinafter described embodies the application to the
heating and ventilating of vehicles of my vaporiser or boiler for producing steam
at a low pressure, which has already formed the subject of a previous Patent
No. 10507, dated 30th May 1894.
In the following Specification, I take, as a type of installation, the heating of a
railway carriage, it being understood that this method of heating may be employed
under similar conditions for omnibuses, tramcars and other like vehicles. As
shown in the accompanying drawings, the application of the system to a railway
carriage having four compartments will be considered.
On the accompanying drawings-
Figure 1, Sheet 1, is a longitudinal section of a heater;
Figure 2 is a longitudinal section of part of a railway carriage showing the
arrangement of foot warmers or heaters in the compartments, as well as the method
of heating such warmers by steam;
Figure 3 is a corresponding plan view, the dotted lines showing the compartments
of the carriage;
Figure 4 shows two perpendicular views of the automatic regulator acting on
the draught of the chimney.
Figures 5 and 6, Sheet 2, show respectively a transverse section and plan view
of a railway carriage compartment with an internal circulation of air warmed by
the heater.
Figures 7 and 8, Sheet 2, show respectively a transverse section and a plan view
of a railway carriage compartment constructed to draw in from the outside fresh
air which is warmed by passing round the heater.
The vaporiser may be placed in the centre of the carriage. It then serves for
foot warmers which are situated in one place or another. The steam produced by
the apparatus passes into the pipes A2 A¹, A³ A Figures 2 and 3, in order to
pass into the four heaters or foot warmers. Each of these latter is arranged as
shown in Figure 1, the upper face B C of the heater is placed at a short distance
from a plate of sheet metal arranged on the floor of the carriage, and on which
the travellers can place their feet. These plates are necessary for avoiding
direct contact with the heaters which receive the steam and are at the temperature
of 100 degrees Centigrade. The bottom of the heater, Figure 1, is inclined so as
to insure the running off of the water arising from the condensation of the steam.
The tube A, which conveys the steam to the heater, serves also for returning the
water of condensation to the vaporiser; for this purpose this tube is inclined
towards the vaporiser, and where it enters the heater, it is formed with an opening,
by which the water runs away whilst the steam is distributed in the heater by the
end e of the tube.
The steam can only spread in the heater if the air be removed therefrom in
some way or other at the moment when the apparatus is set in action. For this
have been compelled to arrange in each heater a tube for discharging
air, shown at a c, Figure 1; each of these tubes is connected to a collector a' a', a³ a,
reason,

page_text: Figure 2 and Figure 3, which connects with the upper part of the feed reservoir
of the vaporiser.
The pipe for discharging the air from each heater may be provided with a tap,
which it suffices to close at the commencement of the working of the apparatus in
order to prevent the escape of the steam these taps are shown at rod t
Figure 2. With this arrangement, it is possible to isolate the condensing surfaces
by means of taps of very small dimensions. This improved arrangement of the
tubes, which only comprises one distributing pipe, forms, as regards its application
to the heating of railway carriages, an important advantage of this method of
heating, because of its extreme simplicity. This improvement is, therefore, an
essential part of this invention.
When the production of steam is no longer equalled by the condensation which
takes place on the heating surfaces, a certain pressure is produced in the whole
apparatus which forms a closed circuit; this pressure increases until it equals the
height to which the manometric tube is immersed in the feed tank; it commences
by warming it, then, when it has brought it to the temperature of 100 degrees, it
passes through it without condensing. It thus reaches the upper part of this tank
and escapes by a tube in direct communication with the outer atmosphere. On
the course of this tube, an automatic regulator is placed, for closing the 'damper in
the chimney, and so moderating the intensity of the fire, so that there is equality
between the production and the condensation. This regulator is shown on Figure 4.
It is formed of a metallic tube of elliptical section wound in a spiral, and filled
with a non-congealable liquid. One of the ends of this tube is fixed to the box in
which it is placed, and the other' is connected by a rod and crank to the axis of
the damper of the smoke shaft. It will be seen from Figure 4 that the excess of
steam, when escaping by the tube d', passes into the box 6 of the regulator, from
whence it passes by the tube c¹ into the atmosphere.
The temperature of this steam causes the liquid contained in the thermometric
tube to expand, the spiral uncoils to a certain extent, and causes the axis of the
damper to turn, which regulates the draught of the chimney. The production of
steam is thus moderated and is balanced exactly by the condensation which is
produced on the heating surfaces.
In addition to its being desirable, from the point of view of economy of fuel,
not to produce too much steam, it is well not to lose any water in order to avoid
frequent refillings of the apparatus, causing expense, which frequent refilling would
cause a rapid formation of scale on the vaporiser.
With this object and in order to condense all the steam which may escape, I
connect the box of the regulator with the double casing of the chimney which is
kept cool by the movement of the train, and which forms a condenser, the water
from which falls back into the feed tank.
In the description which I have just given of the heating apparatus as a whole,
I retained the method at present employed for heating the compartments of a
railway carriage by means of metallic plates occupying the centre of the com-
partment, on which plates the passengers may warm their feet, but I wish to
remark, laying particular stress on this advantage of steam heating, that surfaces
of an entirely different nature and suitable for other results may be employed.
For instance, in order to heat the compartment more highly than can be done
by simple radiation from a foot-warmer, there may be placed under the seats,
heating surfaces fed by a special steam supply. Water may also be heated for a
lavatory. This mode of heating is very readily applicable for a two-storied
carriage, steam distributing itself easily everywhere.
By experiments, I have found that, when only the radiation of a heating plate
was employed for warming the air of the compartment, this plate had to be very
highly heated in order to produce, by its radiation, a sufficiently great difference
between the inside of the carriage and the outside.
I remedy this drawback by means of the arrangements shown in Figures 5, 6, 7
and 8, which have for their object to establish a circulation of air round the

page_text: heater which receives the steam.
In this series of four figures, I give two different.
arrangements, which show that the air which is caused to circulate may be taken,
from the outside or from inside of the compartment.
In the first arrangement, the air passes by the opening a, Figure 5, C d, Figure 6,
into passages which bring it in contact with the heater; the air passes over the
heater from e to B, and from / to B, and then enters the passages h and g, Figure 6,
and escapes under the seats following the arrow b, Figure 5.
In the second arrangement, shown in Figures 7 and 8, the air coming from the
outside at a, Figure 7, or at 'e d, Figure 8, follows the heater from ĕ to h and
from d to h; at h the air enters the two passages and escapes under the seats,.
following the direction of the arrows bc, Figure 7. The heating and ventilation
of the carriage are simultaneously effected by this last process.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In the application of low pressure vaporisers to the heating of vehicles, a
series of single pipes serving simultaneously for distributing the steam to the
various heating surfaces, and for returning to the generator the water of condensa-
tion, the air previously contained being discharged by means of a small pipe with
or without taps, substantially as described with reference to Figures 1, 2 and 3 of
the accompanying drawings.
2. In the application of low pressure vaporisers to the heating of vehicles, the
construction of the heaters or foot warmers, in the form of simple metallic boxes
having horizontal tops and inclined bottoms for carrying off the water to the
distributing tube, which boxes are covered at a short distance away by a plate of
sheet metal of a lower temperature than the box, substantially as described with
reference to Figures 1 and 2 of the accompanying drawings.
3. In combination with the heaters or foot warmers herein before described,.
passages formed in the floor establishing a circulation of the air of the carriage,
or of air drawn from the outside, round the heating surface of the heater,
substantially as hereinbefore described with reference to Figures 5, 6, 7 and 8 of
the accompanying drawings.
Dated this 10th day of September 1894.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.