IMPROVEMENTS IN APPARATUS FOR EFFECTING INTERCHANGE OF TEMPERATURE IN FLUIDS
Year: 1879

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
८८
County of Middlesex, Gentleman, for the Invention of IMPROVEMENTS IN
APPARATUS FOR EFFECTING INTERCHANGE OF TEMPERATURE IN FLUIDS." A
communication from abroad by Jean Baptiste Java Mignon, and Stanislas
Henri Rouart, both of Paris, in the Republic of France, Engineers.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 8th November 1879.
"
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. IMPROVEMENTS IN APPARATUS FOR EFFECTING INTERCHANGE OF
TEMPERATURE IN FLUIDS." A communication from abroad by Jean Baptiste Java
Mignon, and Stanislas Henri Rouart, both of Paris, in the Republic of France,
Engineers.
This Invention relates generally to improvements in apparatus which have for
their object transferring caloric from one fluid to another. The greater part of the
apparatus employed in manufactures are apparatus for effecting an exchange of
temperatures between fluids, consisting either of two liquids, a liquid and a gas or
vapor, or two gases or vapors, all of which fluids however are imperfect conductors
of heat.
It will be understood that the caloric would be more readily abstracted from
these fluids if they were spread out in thinner layers, but in practice great difficulty
bas always been found in the employment of thin layers, because the apparatus
heretofore constructed fulfilling the necessary conditions were liable to become
choked, and it is almost impossible to clean and inspect them.
According to this Invention the fluid is disposed in capillary sheets or layers by
means of apparatus which is capable of being taken to pieces and cleaned with
facility, whereby it is rendered possible by means of apparatus of very small
dimensions to obtain results very superior to the results heretofore obtained, and
this effect is produced in great measure by means of a very rapid renewal of the
points of contact, such renewal being caused by a quick circulation of fluids through
extremely narrow passages.

page_text: The apparatus constructed according to this Invention are composed of a com-
bination of parts, a typical arrangement of which is the following:
Two tubes arranged concentrically one within the other in such a manner as to
leave an annular space of the sinallest dimensions practicable between the external
surface of the inner tube and the internal surface of the outer tube. These two
tubes are connected together by suitable devices ordinarily employed for such
purposes, such, for example, as a conical collar embracing the tubes at the upper
extremity and an annular disc at the lower extremity bearing against the ends of
the tubes and secured by means of screw clamps.
One of the fluids is caused to circulate in the annular space between the two
tubes, whilst the other fluid circulates inside the inner tube and outside the outer
tube in such a manner as to utilize the whole of the surface available for trans-
ferring heat from one of the fluids to the other.
The fluid of any description which circulates in the annular space is introduced
by means of a suitable apparatus provided with radiating tubes, serving to distri-
bute the fluid to different points on the circumference of the internal tube. This
apparatus in one of its simplest forms consists of four bent tubes radiating from a
central circular horizontal plate and communicating at their outer extremities with
the annular space hereinbefore referred to. The form of this distributing apparatus
may be varied according to circumstances. It is evident that when it is required
to obtain a large area of radiating surface a certain number of apparatus similar to
the complete apparatus herein before described may be connected together by placing
them in communication at their upper and lower extremities by means of collectors,
or according to another arrangement by placing them end to end in such a manner
that in the former case the action of a single apparatus is multiplied by increasing
the number of separate annular spaces, and in the latter case by adding to the
effect produced by one annular space to that produced by the succeeding one.
The principal of these apparatus is capable of a large variety of applications, of
which the following are typical examples
In applying the Invention to apparatus for effecting an exchange of temperature
between two liquids, such, for example, as refrigerating apparatus working with an
ammoniacal solution, concentric vessels are employed, substantially similar to those
herein before described, and this part of the apparatus is immersed in liquid con-
tained in a suitable vessel under pressure.
The liquid from which heat is to be extracted enters at the top and is discharged
at the bottom, whilst the liquid which is to absorb heat is caused to enter the
apparatus at the lower part of the vessel containing the concentric tubes, and is
distributed in such a manner that one part of the said liquid flows up the centre of
the concentric tubes so as to act on the inner surface of the inner tube, whilst
another part flows outside the tubes so as to act on the outer surface of the outer
tube.
A cooling apparatus for use in breweries may be constructed in a generally
similar manner, or when it is desired to economise the quantity of water employed
for the cooling it will be necessary to reduce the dimensions of the furnace in which
it circulates, the concentric tubes forming a capillary space between them, being
immersed in the cooling medium contained in a vessel of suitable dimensions.
In applying the Invention to apparatus for effecting an exchange of temperatures
between a gas or vapor and a liquid, the following arrangements may be adopted :-
In the case of steam boilers, the water employed should be distilled by means of
a surface condenser constructed according to this Invention, or the formation of
deposits may be prevented by using water containing a small proportion of
calcareous salts. The boilers supplied with water as herein before described or
otherwise are arranged in the following manner:-The concentric tubes forming
the capilliary space between them are placed in an inclined position underneath a
cylindrical boiler or reservoir of water and steam. The lower extremity of the
capillary space communicates with the bottom of the boiler, and the upper

page_text: extremity communicates with the interior of the boiler at a point a little below the
water level.
A pipe closed at its lower end is passed through the centre of the concentric
tubes for the purpose of directing the products of combustion against the internal
surface of the inner tube; on emerging from this tube the gases circulate freely in
a combustion chamber, where they come in contact with the body of the boiler and
with the external surface of the concentric tubes, and finally escape into a flue at
the point of the boiler.
When it is required to heat a boiler by means of lighting or other gas, the gas is
caused to flow into the central pipe, a certain number of suitable orifices being
provided for the escape of the gas. This arrangement is peculiarly adapted for
apparatus for heating buildings, the annular space being supplied with water at its
lower extremity from a suitable reservoir which is substituted for the cylindrical
boiler and the upper extremity of the annular space communicating with a steam
chamber.
The internal gas pipe is prolonged at its upper extremity so as to conduct the
products of combustion to a chamber for collecting the burnt gas which finally
escapes into a chimney. A supplementary reservoir serves to compensate for the
small waste of water which takes place.
The system of concentric tubes arranged according to this Invention is applicable
to steam condensers worked with water for marine and land engines, the steam
being condensed with rapidity in the annular space formed between the concentric
tubes.
Under this application of the Invention additional sets of tubes may be employed
capable of being cut off or isolated from each other by means of valves, so as to
render it possible to proceed with the cleaning of any one set of tubes with great
facility while the apparatus is at work.
A reservoir of water is interposed between the condenser and the feed pump, a
vacuum being maintained in the said reservoir by the action of the pump or by a
steam jet.
In applying the Invention to the heating of liquids by means of steam the
concentric tubes are supported vertically at a certain distance from the bottom of
the vessel containing the liquid to be heated and are entirely immersed in such
liquid. The steam enters the apparatus through a pipe passing through the bottom
of the vessel, and rising through the centre of the concentric tubes so as to com-
municate by means of suitable radiating branch pipes with the upper extremity
of the annular space in which the steam circulates, and after transferring its heat
to the liquid it is discharged through suitable pipes at the lower part of the
apparatus.
The Invention is also applicable for effecting an exchange of temperature between
two gases or vapors in apparatus for heating air by means of steam or gas, apparatus
for condensing steam by means of air, and hot air apparatus for use in metallurgy
or other arts and manufactures.
In applying the Invention to the heating of air by means of steam, the steam
circulates in the annular capillary space of concentric tubes which are enclosed in a
suitable case open at the bottom for the admission of cold air, and provided with
suitable orifices at its upper part for the escape of the heated air. An internal
cylinder is placed inside the concentric tubes so as to form an annular space for the
passage of air between the outer surface of the cylinder and the inner surface of
the internal concentric tube.
The steam enters the apparatus through a pipe passing through the centre of the
cylinder, and communicating with the upper part of the annular capillary space by
means of radiating branch pipes. The steam circulates in this annular space and
transfers its heat to the cold air which enters at the lower end of the case, and
passes through the annular spaces formed between the concentric tubes and the
cases, and between the concentric tubes and the internal cylinder, after which it
escapes through orifices at the upper part of the case.

page_text: When the Invention is applied to the heating of air by means of gas the concentric
tubes forming an annular capillary space between them may be set in a casing of
brickwork, or other suitable material, in such a manner as to form annular passages
between the said casing, and the inner surface of the inner tube and the outer
surface of the outer tube. The air to be heated enters the apparatus through a pipe
communicating with the lower part of the capillary annular space and escapes at
the upper part.
The gas issues in jets from a pipe in the form of a ring situate underneath the
concentric tubes, and the products of combustion ascend through the annular
passages herein before referred to, coming in contact with the inner surface of the
inner tube and the outer surface of the outer tube, at the same time transferring its
heat to the air in the annular space between the said tubes, after which escapes
through suitable outlets at the upper part of the apparatus.
The casing may be made hollow and the combustible gases may be caused to pass
through it, a certain number of gas jets being suitably arranged at the sides of the
casing in lieu of the ring of jets hereinbefore described. A fan may be employed
to accelerate the circulation of the air.
In applying the Invention to the condensing of steam by means of air, as, for
example, in the case of locomotive engines, the requisite amount of surface may
be obtained by making the tubes in lengths which may conveniently be carried
upon the tender. The tubes may be arranged lengthwise in a slightly inclined
position so as to form a slight angle with the horizon or vertically, the steam being
introduced at the bighest point and the water of condensation being discharged at
the lowest point, and thence returned to the boiler.
In the construction of boilers for locomotive engines several lengths of concentric
tubes are employed placed in an inclined position underneath a cylindrical vessel or
boiler, or reservoir for water and steam not used for generating steam, but simply
acting as a reservoir for steam and water. The annular spaces between the tubes
communicate at each end with the cylindrical vessel, and the products of combustion
pass from a fire box through the central tubes and return to the chimney after
coming in contact with the outer surface of the outer tubes.
When the Invention is applied to hot air apparatus for metallurgical purposes a
suitable number of lengths of concentric tubes forming annular capillary spaces
between them are arranged in a chamber at the lower extremity of a chimney for
creating a draft. The hot gases from a blast furnace enter the chamber at the
lower part, and escape from the upper part into the chimney after passing through
and between the tubes and transferring their heat to the air which is caused to
circulate in the annular capillary spaces formed by the said tubes. The air to be
heated is forced into the apparatus by a blowing engine, and enters the chamber
through a main pipe situate at the upper part, from which it is distributed to the
capillary spaces by means of suitable branch pipes, and leaves the apparatus through
a corresponding arrangement of branch pipes communicating with a main pipe at
the lower part of the apparatus by which it is conducted to the upper part of the
furnace.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 7th
May 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN APPARATUS FOR EFFECTING INTERCHANGE OF
TEMPERATURE IN FLUIDS." A communication from abroad by Jean Baptiste Java
Mignon, and Stanislas Henri Rouart, both of Paris, in the Republic of France.
The said Invention relates generally to improvements in apparatus which have
for their object transferring caloric from one fluid to another.
The greater part of the apparatus employed in manufactures are apparatus for
effecting an interchange of temperatures between fluids consisting either of two
liquids, a liquid and a gas or vapor, or two gases or vapours, all of which fluids
however are imperfect conductors of heat.
It will be understood that the caloric would be more readily abstracted from
these fluids if they were spread out in thinner layers, but in practice great difficulty
has always been experienced in the employment of thin layers, since the apparatus
heretofore constructed fulfilling the necessary conditions were liable to become
obstructed, and it is almost impossible to clean and inspect them.
According to this Invention the fluid is disposed in capillary sheets or layers by
means of apparatus which is capable of being taken to pieces and cleaned with
facility, whereby it is rendered possible by means of apparatus of very small
dimensions to obtain results very superior to those heretofore attained, and this
effect is produced in great measure by means of a very rapid renewal of the points
of contact, such renewal being caused by a quick circulation of fluids through
extremely narrow passages.
The apparatus constructed according to this Invention are composed of a
combination of parts, as hereinafter described with reference to the two Sheets of
Drawings hereunto annexed.
Figure 1 of the accompanying Drawings represents a plan, vertical section, and
horizontal section of an apparatus constructed according to the said Invention for
transferring caloric from one fluid to another.
In this arrangement, which may be considered as an exemplification of the
general principles of the Invention, two tubes a, a', Figure 1, are employed, formed
of metal and of suitable diameter, the said tubes being arranged concentrically one
within the other in such a manner as to leave an annular space x of the smallest
dimensions practicable between the external surface of the inner tube and the
internal surface of the outer tube. These two tubes are connected together by
suitable devices ordinarily employed for such purposes, such, for example, as a
conical collar b embracing the tubes at the upper extremity, and an annular disc c
at the lower extremity bearing against the ends of the tubes and secured by means
of screw clamps.
One of the fluids is caused to circulate in the annular space x between the two
tubes, whilst the other fluid circulates inside the inner tube a¹ and outside the
outer tube a in such a manner as to utilise the whole of the surface available
for effecting an interchange of temperature between the two fluids.
The fluid (which may be of any description) which circulates in the annular
space is introduced by means of a suitable apparatus d provided with radiating
tubes e, serving to distribute the fluid to different points on the circumference of
the internal tube. This apparatus in one of its simplest forms consists of four bent
tubes e radiating from a circular horizontal plate f and communicating at their
outer extremities with the annular space x. The form of this distributing
apparatus may be varied according to circumstances.
It is evident that when it is required to obtain a large area of radiating surface
a certain number of apparatus, similar to the complete apparatus represented in
Figure 1, may be connected together by placing them in communication at their

page_text: FIRST SERIES.
Apparatus for effecting an interchange of temperatures between two liquids.
This class of apparatus is subdivided into two distinct types according as one or
both of the two interchanging liquids are under pressure.
The refrigerating apparatus working with an ammoniacal solution known as
Mignon & Rouart's, may be taken as an example of the first type of apparatus. In
this apparatus, which is represented in vertical section in Figure 3, an annular
capillary space x formed between two concentric tubes a and a¹, capable of resisting
pressure, is closed at its upper and lower extremities by means of suitable covers k
provided with passages for the inlet and outlet of the liquid; this part of the
apparatus is immersed in liquid contained in a suitable vessel 6 under pressure.
The liquid from which heat is to be abstracted is introduced into the apparatus by
means of a pipe h passing through a stuffing box c in the cover of the vessel b,
and communicating with the upper extremity of the annular space x by means of
radial branch pipes e for the better distribution of the said liquid, which escapes at
the lower extremity of the annular space through a similar arrangement of radial
branch pipes communicating with a suitable outlet pipe d. The liquid which is to
absorb beat is caused to enter the apparatus through an inlet e' at the lower part
of the vessel b and is distributed in such a manner, as shown at f, that one part of
the said liquid flows up the centre of the concentric tubes so as to act on the inner
surface of the inner tube, whilst another part flows outside the tubes so as to act
on the outer surface of the outer tube. A suitable outlet pipe g is provided at the
upper part of the apparatus for the escape of this liquid.
When ammonia is employed the apparatus is composed of iron, the parts not
being soldered together or soldered to other metals, whereby great solidity of
construction is obtained. The apparatus moreover is most efficient in its operation.
A cooling apparatus for use in breweries may be taken as an example of the
apparatus in which one only of the liquids is under pressure.
The general arrangement herein before described may be employed for this
purpose by allowing the beer which it is desired to cool to circulate in the interior
of the capillary space, whilst the water for absorbing heat circulates on the exterior.
When it is desired to economise the quantity of water employed for the cooling it
will be necessary to reduce the dimensions of the furnice in which it circulates,
ad pting for this purpose the arrangement represented in sectional elevation und
horizontal section in Figure 4, in which the concentric tubes forming a capillary
space between them are immersed in the cooling medium contained in a vessel b of
suitable dimensions. By means of this arrangement the interchange of temperatures
is more complete, the cooling water leaves the apparatus at a higher temperature,
and consequently a smaller quantity of water is employed.
SECOND SERIES.

page_text: Steam boilers heated directly by coal or gas surface condensers and apparatus
for heating liquids by steam afford examples of this description of apparatus.
First Example.-Steam Boilers.
Steam boilers in which a capillary space constructed according to this Invention
is employed should preferably be supplied with distilled water obtained by means of a
surface condenser constructed according to this Invention, or otherwise, the capillary
passage will be liable to become obstructed. It should be remembered however
that in the case of a very rapid circulation the formation of deposits is prevented
when water containing a small proportion of calcareous salts is employed. The
boilers supplied with water as herein before described, or otherwise, are arranged as
represented in sectional elevation in Figure 5; the concentric tubes a, a¹, forming
the capillary space x between them, herein before described, are placed in an inclined
position underneath a boiler or reservoir A containing water and steam. The lower
extremity of the capillary space a communicates with the bottom of the boiler by
means of a pipe f, and the upper extremity communicates with the interior of the
boiler by means of a pipe fi at a point a little below the water level. The lower
extremities of the concentric tubes are united by means of flanges a², and the same
flanges serve to attach the tubes to a plate b forming the back of the furnace.
iron pipe c closed at its lower end d is passed through the centre of the inner tube a¹
for the purpose of directing the products of combustion against the internal surface
thereof. On emerging from the inner tube the gases circulate freely in a combus-
tion chamber B, where they come in contact with the body of the boiler and with
the external surface of the concentric tubes, and finally escape into a flue C at the
front of the boiler, as shown by the arrows.
An
When it is required to heat a boiler by means of lighting or other gas the gas is
caused to flow into the central iron pipe i, a certain number of suitable orifices
being provided for the escape of the gas. This arrangement is peculiarly adapted
for apparatus for heating buildings, in which case the arrangement represented in
sectional elevation in Figure 6 is adopted. In principle by the employment of this
apparatus there will be no waste of steam, and consequently no waste of the water
contained in the boiler; the dimensions of the cylindrical body of the boiler may
consequently be reduced to a minimum. The boiler is constructed in the following
manner :-
Two concentric tubes a, a¹, forming an annular capillary space a between them
are arranged in an inclined position, being connected at their extremities by means
of collars or flanges a³, which also serve to close the extremities of the annular
space x. The annular space is supplied with water at its lower extremity from
a suitable reservoir b which is substituted for the boiler A, Figure 5, and the upper
extremity of the annular space communicates with a steam chamber d. The water
contained in the annular space is heated by means of jets of gas issuing from a gas
pipe c placed in the centre of the concentric tubes, the flame being caused to
impinge against the internal surface of the inner tube, which is prolonged at its
upper extremity at h so as to conduct the products of combustion to a chamber 6
for collecting the burnt gas, which finally escapes into a chimney f. A supple-
mentary reservoir g serves to compensate for the small waste of water which takes
place.
This arrangement of generator has the advantages of enabling the required heat
to be applied almost instantaneously and of being perfectly safe, whilst it admits
of the amount of heat generated being increased or diminished by simply moving a
valve or cock in the gas pipe, which operation may be performed from any con-
venient part of the building. The pressure in the boiler may be limited to a given
maximum amount by means of a simple device acting upon the supply of gas.
Second Example.-Surface Condensers.
The system of concentric tubes arranged according to this Invention is applicable
to steam condensers operating with water, for marine and land engines, the
steam being condensed with great rapidity in the annular space formed between
the concentric tubes (Figure 1).

page_text: This power of condensation is of peculiar advantage in the case of marine engines
where economy of space is of considerable importance, and from the facility also
with which the apparatus may be taken to pieces and cleaned. The apparatus
constructed according to this system becomes of great value in steam navigation.
It will be observed that the action of the capillary passages is liable to be
paralysed by the accumulation of grease deposited by the steam, as is always the
case with surface condensers. The remedy for this defect is extremely simple.
When the condensing surface requires the employment of, say, six similar sets of
tubes, for example, seven or eight sets of tubes are employed capable of being cut
off or isolated from each other by means of valves, as shewn at fin Figure 2, so as
to render it possible to proceed with the cleaning of any one set of tubes with
great facility while the apparatus is at work.
It should also be observed that the condensation taking place in the annular
capillary spaces will produce a vacuum therein, and by reason of the narrowness of
the condensing spaces the water would be liable to be held in suspension and
interfere with the progress of the condensation.
In order to remedy this defect the arrangement shown in elevation in Figure 7
may be adopted, in which a reservoir A of water is interposed between the con-
denser B and the feed pump C, a vacuum being maintained in the said reservoir by
the action of the pump A. or by a steam jet.
Third Example.-Heating Liquids by Steam.
Steam heating apparatus are generally composed of coils of pipes or worins which
may be replaced with advantage by the annular capillary spaces constructed
according to this Invention.
For example, when it is required to heat a vessel or boiler containing a liquid
the arrangement represented in vertical section in Figure 8 may be employed.
According to this arrangement the concentric tubes a, a', are supported vertically
at a certain distance from the bottom of the vessel containing the liquid B which it
is desired to heat, and are entirely immersed in the said liquid. The steam enters
the apparatus through a pipe c, passing through the bottom of the vessel A. and
rising through the centre of the concentric tubes so as to communicate by means of
suitable radiating branch pipes e with the upper extremity of the annular space
in which the steam circulates, and after transferring its beat to the liquid it is
discharged in a wholly or partially condensed condition through suitable pipes d at
the lower part of the apparatus. By this arrangement an apparatus of great power
is obtained possessing great strength, and which is easily kept in order.

page_text: The steam enters the apparatus through a pipe d passing through the centre of
the cylinder b and communicating with the upper port of the annular space x by
means of radiating branch pipes e; the steam circulates in this annular space, and
transfers its heat to the cold air, which enters at the lower end of the case and
passes through the annular spaces formed between the concentric tubes and the
case 61, and between the concentric tubes and the internal cylinder b, the air
thence escaping through the orifices g at the upper part of the case. Pipes e' are
provided at the lower part of the space for the escape of water of condensation.
Second Example.-Heating Air by Gas,
Figure 10 represents in vertical section the arrangement which it is preferred
to employ in carrying out this part of the Invention. The concentric tubes a, a²,
forming an annular capillary space between them are set in a casing b, c, of
brickwork or other suitable material in such a manner as to form annular passages
o, o, between the said casing and the inner surface of the inner tube and the outer
surface of the outer tube. The air to be heated enters the apparatus through a
a pipe A communicating with the lower part of the capillary annular space x by
means of radiating branch pipes e¹, and escapes from the apparatus after circulating
in the capillary space x through a similar arrangement of branch pipes e¹ at the
upper part of the said space communicating with a main pipe f. The gas issues in
jets from a pipe d in the form of a ring situate underneath the concentric tubes,
and the products of combustion ascend through the annular passages o, o, at the
same time transferring their heat to the air in the annular space x, after which they
escape through suitable outlets g, g¹, at the upper part of the apparatus. The walls
of the casing may be made hollow, and the combustible gases may be caused to
circulate on their interior, a certain number of gas jets being suitably arranged at the
sides of the casing in lieu of the ring of jets d. The rate of speed with which the
air circulates in the annular space should be regulated in proportion to the heating
action of the gas jets; a fan or other suitable apparatus may therefore be employed
if it be required to accelerate the circulation.
Third Example. Apparatus for Condensing Steam by means of Air.
Apparatus for this purpose may also be constructed upon the principles herein-
before enunciated. In the construction of a surface condenser for a locomotive
engine, for example, a sufficient number of lengths of tubes may be conveniently
carried upon a tender, as shewn in sectional elevation in Figure 11. In this
example the tubes are arranged lengthwise in a slightly inclined position, a, a, being
the tubes, and b the body of the tender. The tubes may however be placed
vertically. The steam is introduced at the highest point, and the water of
condensation is discharged at the lowest point, and thence returned to the boiler
by the means hereinbefore described with reference to the condensers working with
water.
It is evident that the activity of the condensing surface will depend upon the
rapidity of the motion of the train, because the air coming in contact with the tubes
will effect a more rapid interchange of temperature in proportion to the rate of
travelling.
By these means the boilers of locomotive engines may be supplied with chemically
pure water, and the small quantities which it is necessary to introduce in order to
compensate for losses by leakage, or in the form of steam blown through the
whistle or the safety valve or employed to create a draft in the furnace, may consist
of distilled water, or water of sufficient purity provided at suitable fixed points
on the line.
This purity of the water enables boilers constructed with concentric tubes and
capillary spaces as hereinbefore described to be employed for locomotive engines.
An example of this application of the Invention is represented in sectional elevation
in Figure 12. According to this arrangement several lengths of concentric tubes
a, a¹, a³, are employed placed in an inclined position underneath a cylindrical vessel
or boiler B, or a reservoir for water and steam, not used for generating steam, but
simply acting as a reservoir for steam and water. The annular spaces between the

page_text: tubes communicate at each end with the vessel B, and the products of (combustion
generated on a grate C in a fire box D first pass through the central tubes and
circulate in a space E in contact with the outer surface of the outer tubes, and are
finally discharged into the chimney F. By means of these arrangements the
following advantages are obtained, videlicet:-The necessity for taking in water
at the stations is in a great measure obviated; perfect facility is afforded for
inspecting, keeping in order, and cleaning the evaporating surfaces; the trains are
enabled to travel greater distances without the necessity for stopping, and a great
saving of fuel is effected by employing low pressure in lieu of high pressure
engines.
It is evident that these condensers are equally applicable to stationary or to
portable engines, and in this case also are productive of advantages analogous to
those described with reference to locomotives.
Fourth Example.-Hot Air Apparatus used in Metallurgy.
Apparatus in which hot air is employed for metallurgical operations are usually
of considerable dimensions, and consequently extremely costly. This is a result
of the imperfect interchange of temperature between the fluids gas and air, which
are both imperfect conductors of heat.
Now by means of this Invention the dimensions of the apparatus and the corre-
sponding expense may be considerably reduced by employing the annular capillary
spaces hereinbefore described of suitable dimensions.
The arrangement which it is preferred to employ in carrying out this part of the
Invention is represented in sectional elevation in Figure 13. It consists in dis-
posing a suitable number of lengths of the concentric tubes a in a chamber Bat
the lower extremity of a chimney D for creating a draft. The hot gases from a
blast furnace enter the chamber at the lower part through a pipe C, and escape
from the upper part into the chimney D after passing through and between the
tubes a, and transferring their heat to the air, which is caused to circulate in the
annular capillary spaces formed by the said tubes. The air to be heated is forced
into the apparatus by the blowing engine, and enters the chamber through a main
pipe E, from which it is distributed to the capillary spaces by means of suitable
branch pipes e, and leaves the apparatus through a corresponding arrangement of
branch pipes e¹ communicating with a main pipe f, from which it is conducted to
the blast furnace through a pipe g, which should be made as short as possible.
The apparatus for condensing gases and vapours and thereby heating masses of
gas or liquid by the employment of annular capillary spaces, as herein before
described, may also be applied to the condensing apparatus employed by sugar
manufacturers by means of special arrangements of the apparatus, as next herein-
after described.
This improved apparatus is designed with a view to facilitate the cleaning of
the evaporating apparatus employed in the manufacture of sugar, and more par-
ticularly of what is known as triple effect evaporating apparatus. With this object
the capillary spaces are applied to the apparatus ordinarily employed, a series of
the concentric tubes forming an annular capillary space between them being
immersed in the syrup to be evaporated.
This arrangment is illustrated in Figures 14 and 15, Sheet 2 of the Drawings,
Figure 14 being a vertical and horizontal section of the apparatus, and Figure 15
a detail of a portion of one of the sets of concentric tubes. According to this
arrangement an evaporating pan A is provided with a series of concentric tubes a, a¹,
(Figure 15), forming capillary spaces x, as herein before described, the said tubes
being arranged in circles, as shewn clearly in Figure 14. Steam is admitted
through a central inlet pipe C, and is supplied to the several tubes by a suitable
number of distributing pipes o leading to annular pipes d, which communicate with
the tubes a by means of branch pipes e. It will be observed on reference to
Figure 15 that the branch pipe e debouches into an annular chamber g formed on
the exterior of the tube a. This chamber communicates with the annular capillary
space
by means of a series of orifices h suitably arranged for the purpose of

page_text: distributing the steam as uniformly as possible in the annular space. The water
of condensation escapes at the lower part of the spaces x through chambers g¹,
branch pipes el, circular pipes d', distributing pipes o¹, and an outlet pipe C passing
through the bottom of the evaporating pan, the whole constituting a similar
arrangment to that described for the admission of the steam but of somewhat
smaller dimensions. This symmetrical arrangement of the parts enables the
apparatus to work more uniformly, but is not indispensable. One or more circles
of the tubes forming the capillary spaces may be employed as required, but care
should be taken to make the distributing pipes in proportion to each annular pipe,
so that the supply may be as uniform as possible.
By means of the arrangement, described with regard to the annular capillary
spaces the operation of taking the parts to pieces is greatly facilitated, and the
efficient cleaning of the same may consequently be effected whenever required.
The heating surfaces thus arranged are so effective as to enable the dimensions
of the apparatus to be reduced.
It is obvious that the vapours generated in one pan may be caused to pass on to
a second, where, by an arrangement analogous to that hereinbefore described,
similar results are obtained by their agency. The same arrangement is adopted
with regard to the third and following pans when such are employed, which, it may
be presumed, will be the case, because in the arrangement adopted the effectiveness
of the heating surfaces enables ebullition to be produced with a very slight
difference of temperature between the liquid to be evaporated and the steam or
vapours employed to produce the evaporation.
The form adopted, according to this Invention, for constructing steam condensers,
which, in this case, are employed as heating apparatus for syrup, further enables
the said apparatus to be arranged in a totally different manner to the apparatus
heretofore employed and facilitates the continuous working.
For this purpose the apparatus is arranged as shewn in sectional elevation in
Figure 16, in which the tubes forming the annular capillary space, and propor-
tionate to the effect which it is desired to obtain, are placed in the centre of a
vessel B of suitable dimensions, and are immersed in the syrup to be evaporated.
The steam is introduced into the apparatus through a pipe d, and the water of
condensation escapes through a pipe b; the liquid to be concentrated enters by a
pipe d, and is discharged through an outlet f into a pipe b', whilst the vapours
escape through a pipe C. In proportion as the syrup becomes concentrated its
density increases, and it tends to sink to the bottom, so that the most concentrated
portion falls to the lower part of the vessel, where its escape is regulated by means
of a cock k.
In order to enable this apparatus to work under favorable conditions it is
necessary for the whole of it to be practically at boiling temperature. Now, some
some difficulty has been experienced in fulfilling this condition with regard to the
incoming liquid, which could not be raised to the required temperature except by
employing a special heating apparatus, but a satisfactory result may be obtained
while utilising at the same time the residual heat remaining in the water of con-
densation and that of the concentrated syrup. For this purpose it is sufficient to
employ any apparatus which will effect an interchange of temperature between
these liquids.
The desired effect may be produced by means of apparatus of great simplicity
hereinafter described.
These apparatus may be divided into two classes according as they work under
pressure or under a vacuum. The former is illustrated in Figure 16, in which the
supply of liquid to be evaporated is contained in a reservoir m, whence it passes
through a pipe o into a vessel n below the reservoir. The difference between the
level of the reservoir m and that of the vessel n corresponding to the excess of
pressure required, and the rapidity of the flow being regulated by a cock p. The
upper part of the vessel n is placed in communication with the vessel B by means

page_text: of the pipe d' hereinbefore referred to. The pipe 6 for the escape of the con-
centrated liquid passes through the vessel n, and discharges the liquid at a level
corresponding to the excess of pressure, whilst the water of condensation passes
through an annular capillary space formed by the tubes a similar to the tubes a, a¹,
herein before described, and also arranged within the chamber n, and the water is
finally discharged through a pipe I.
When the apparatus works with a vacuum the parts for effecting the interchange
of temperature are arranged as described with reference to Figure 16, it being
simply necessary to place the inlets and outlets for the liquids at a level situate, a
sufficient distance below the vessels n and B to counter balance the atmospheric
pressure, as shewn in Figure 17. In this Figure similar letters are used to denote
the same parts as in Figure 16.
If preferred, a suitable arrangement of pumps may be employed to produce the
desired effect in lieu of the automatic arrangement described.
The capillary spaces have been described as being applicable to the condensation
of steam by means of air, thereby enabling high pressure engines to be converted
into condensing engines with all the advantages of that system.
These atmospheric condensers are particularly adapted for stationary and
semi-portable engines. It is evident that the condensing action will be rendered
more efficient in proportion as the coldness of the air employed is increased, and if
due effect is given to this condition the dimensions of the condensing surfaces will
admit of being considerably diminished.
The earth possesses the property of preserving a practically uniform temperature
at a certain depth below the surface, and this phenomenon is utilised in order to
obtain the desired effect. For this purpose surfaces formed by pipes of cast iron or
other material constituting a sufficiently good conductor are arranged at a suitable
depth below the surface of the ground, and atmospheric air is drawn through these
tubes by means of a fan, and then forced into the condenser.
In arranging the capillary space for cooling the air the following directions
should be observed videlicet: :-
The refrigerating surfaces or tubes should be arranged in the form of a grid or
grating placed at a proper depth, and the air which has been cooled in its passage
over the said cooling surfaces should be collected in a main and conducted to the
surface of the ground by means of a single pipe of large diameter, and constructed
of non-conducting material, or at least sufficiently separated from the earth to
prevent the air from being warmed during its ascent.
In some cases a certain quantity of water is available too small to produce the
direct condensation of the whole of the steam escaping from the engine, but by
causing this water to flow in thin sheets over the capillary surfaces or tubes, the
current of air circulating in the same will be the means of causing an evaporation
which will have the desired effect.
If necessary, the capillary surfaces or tubes may in this particular case be
enclosed in a covering of porous materials, especially woven fabrics, which, by
preserving the moisture on the sides will contribute to producing the desired
effect.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that as the Invention is of very extensive
application it has not been possible to give more than examples of principal types
constructed in accordance therewith, I wish it to be understood therefore that I do
not confine myself to the examples herein before given for the purpose of elucidating
the Invention, for example, in the case of apparatus for distilling and condensing
vapours of every description. The Invention is applicable for effecting heating
and condensation, say, for example, in refrigerating apparatus and the like, and
other applications of the Invention will readily suggest themselves to practical

page_text: men. What I consider to be novel and original, however, and therefore claim
as the Invention secured to me by the hereinbefore in part recited Letters
Patent is,―
The employment of apparatus consisting of concentric cylinders, tubes, or vessels
with capillary annular or intermediate spaces, the parts being so fitted together as
to be capable of being readily taken to pieces for cleaning, and the apparatus being
arranged generally so as to operate substantially in the manner and for the
purposes herein before described and as illustrated by the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my Specifi-
cation set my hand and seal, the Seventh day of May, One thousand eight
hundred and eighty.
J. HENRY JOHNSON. (L.S.)