IMPROVEMENTS IN THE MEANS AND APPARATUS FOR EFFECTING REFRIGERATION
Year: 1878

page_text: LETTERS PATENT to Matthew Piers Watt Boulton, of Tew Park, in the County
of Oxford, for the Invention of "IMPROVEMENTS IN THE MEANS AND APPARATUS
FOR EFFECTING REFRIGERATION."
Sealed the 28th January 1879, and dated the 9th November 1878.
PROVISIONAL SPECIFICATION left by the said Matthew Piers Watt Boulton
at the Office of the Commissioners of Patents on the 9th November 1878.
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford. “IM-
PROVEMENTS IN THE MEANS AND APPARATUS FOR EFFECTING REFRIGERATION."
This Invention relates to means and apparatus for effecting refrigeration by the
expansion of compressed air or elastic fluid. One of its objects is to produce by
means of such apparatus an intense degree of cold, much exceeding any hitherto
attained by such means, and also to combine it with apparatus for effecting the
liquefaction of gases.
For effecting the compression I employ the known method of stage pumping and
the expansion of the similar known method of expanding by stages.
The pumps
are worked by an engine; the air or fluid acting in the expansion cylinders assists
the engine. This combined apparatus for pumping and expanding by stages will be
spoken of by me as the stage cylinder apparatus.
For abstracting the heat of compression I avoid all internal injection of water.
It is important for the object aimed at to keep the interior of the apparatus
perfectly free from moisture, because the congelation of this by the evolution of
latent heat greatly impairs the refrigerant action; I therefore abstract the heat of
compression solely by external agency of water or other cooling agent; such a
method is frequently practised in the compression of air.
For like reason I perfectly dry the air or elastic fluid supplied to the pumps.
This drying may be effected by passing the fluid over or through chloride of calcium,
or sulphuric acid, or other known absorbents.
In some cases a mode of drying may be used which I shall afterwards explain.
'

page_text: In the stage cylinders I employ each cylinder both for compression and expansion,
compression taking place on one side of the piston and expansion 'on the other.
The piston rod works on the side on which the compression takes place. To prevent
passage of heat from one portion of the cylinder to the other and to protect the
liquid which lubricates the piston from exposure to intense cold the piston is
furnished with a shield on the side of expansion. This shield is so made
as to abstract passage of heat, for which purpose various substances may be used.
Further, for the same object the cylinder is made in parts, and vulcanite or
some substance which obstructs the passage of heat is placed in the joint or
joints.
The expansion cylinders are also covered or protected by some substance which
obstructs the passage of heat.
For the lubrication of the piston I consider that glycerine is suitable on account
of its slight volatility. It may, if desired, be protected from the action of the
warmth on the side of compression by a shield, and thus may work on a part of the
cylinder kept at somewhat low temperature, where it can neither be frozen nor give
off any gaseous or vaporous matter.
The precautions above described are principally called for in those cylinders in
which on one side intense degree of cold exists and are not so necessary in the earlier
stages, though not useless even there.
The air or elastic fluid on issuing from the final expansion cylinder passes into a
chamber where it exerts refrigerant action in any manner desired.
After having
done this it passes back to the first pump and is again subjected to the stages of
compression and expansion.
The refrigerant air or fluid being thus continually used over and over again may
be employed in the refrigerant chainber at any pressure desired. I consider it
desirable for the purpose in view to use it at high pressure so that in virtue of its
greater density it may exert more powerful refrigerant action.
Also by the employment of high-pressure air or fluid the bulk of cylinders and
moving parts in the refrigerant apparatus may be much reduced.
The refrigerating chamber is covered or protected by some substance which
obstructs the passage of heat.
Loss by leakage of the air or fluid employed is supplied by a pump. This in
some cases may be done by a hand pump occasionally worked, but it may with
advantage be done regularly by means of a feed pump worked by the engine, the
supply to which is governed by the pressure within the refrigerated chamber. This
feed pump is supplied from a vessel or reservoir containing the air or fluid used in
the apparatus in a perfectly dry state.
When it is desired to produce a very intense degree of cold hydrogen may be
employed as the refrigerant fluid, because by carrying the operation far a degree of
cold may be attained at which air would liquefy.
When it is intended to liquefy a gas then within the chamber cooled by the
refrigerant fluid a series of stage compression pumps is provided, and these are
supplied with the gas to be liquefied, already cooled; the heat of compression gene-
rated in these pumps is abstracted by the refrigerant fluid circulating through the
chamber in its course from the expansion cylinders to the compression pumps;
and the compressed gas operated on is delivered into a vessel cooled in a similar
manner.
It is well so to arrange the compression pumps that their piston rods work within
the refrigerating chamber, being driven by a crank shaft passing through the
chamber. Passage of heat through the shaft is obstructed by means of a joint,
with vulcanite or suitable material interposed between the pieces or flanges of the
metal.
The better to effect the abstraction of heat of compression a blower of any
suitable kind, worked by the engine, is provided within the refrigerating chamber
or in connection with it, and this causes a current of the refrigerant fluid to pass

page_text: round the cylinders in which the gas is compressed and the tubes through which it
passes and the vessel or chamber into which it is delivered.
This vessel or chamber may be an arrangement of tubes or passages exposing a
large surface to the action of the refrigerant fluid. Many of the known forms of
heating and cooling vessels are applicable for this purpose.
When it is desired to produce very intense degrees of cold after the liquefaction
of a gas has been effected a further degree of cold may be attained by the evaporation
of the liquid.
In many cases in which refrigeration is needed, the object aimed at is to produce
only a moderate degree of cold, for instance to cool the air in a room or chamber to
a temperature not much below the freezing point.
In such a case it is not necessary to employ a high degree of compression and
expansion, and the use of stage pumping may be dispensed with. Nevertheless
even in this case I consider it advantageous to produce an intense degree of cold in
the refrigerant air or fluid, and employ this to give the moderate degree of cold to
the air of the room or substance to be moderately cooled.
One mode of effecting this is to employ an apparatus such as above described and
cause the air or fluid intensely refrigerated in it to act in a refrigerator or cooling
vessel, which cools the air or other fluid or matter which it is desired to cool to a
moderate degree.
.
The refrigerating chamber may, as mentioned previously, be one of the numerous
forms of vessels presenting large surface employed for heating and cooling
purposes.
When a room or chamber is cooled in this way the air cooled by the refrigerator
is caused to circulate through the chamber by any suitable apparatus, so as to
produce nearly uniform temperature in the chamber, and so in other cases where it
is desired to cool fluid in like manner.
The air issuing from the refrigerator may be deprived of its moisture by any
known method. The following is one method which I employ
:-
I cause the cold air to pass through a saline solution at low temperature. It is
caused to pass through the liquid in small bubbles; sheets of wire gauze or per-
forated material may be employed to effect this subdivision.
In passing through the saline solution at low temperature the snow suspended in
the air is liquefied and detained. As the solution becomes weaker by liquefaction
of the snow more salt is added.
The cold saline solution thus obtained may in some cases be used for refrigerant
purposes.
The salt can always be obtained from it again by boiling and the distilled water
utilised.
Otherwise the cold air which it is desired to dry may be caused to pass in contact
with surfaces saturated with the saline solution.
The method of drying above described may also be employed to dry the air or
fluid employed in the refrigerating apparatus. For this purpose a single cylinder
which compresses and expands to a moderate degree, and produces a moderate
degree of cold is combined with an apparatus of successive or stage cylinders which
produces great compression and expansion and an intense degree of cold.
Air is first passed through the first mentioned apparatus and dried as previously
explained, and the air so dried and moderately refrigerated supplies the stage
cylinder apparatus and is intensely refrigerated therein.
By the application of this method the air of a chamber which it is desired
moderately to refrigerate may be passed directly through the stage cylinder
apparatus without the intervention of the refrigerator as in the method previously
explained.
The intensely cold current of air issuing from the stage cylinder apparatus
is not allowed to issue directly into the room or chamber, but is passed first into a
vessel in which it mixes with a further portion of air supplied from the chamber,
the mixture being thus brought to a moderate degree of cold, and the moderately
..

page_text: cold current issuing from this vessel is caused to circulate through the room or
chamber by means of any suitable known apparatus.
The mixture of the intensely cold air with the further portion of air may
be effected in various ways. The current of the less cold air may be produced
by a separate instrument and injected by means of this into the chamber into which
the stream of intensely cold air issues from the refrigerating apparatus.
But I consider it advantageous to dispense with the separate instrument and
effect the mixture by means of the pressure which impels the intensely cold current
in its issue from the stage cylinder apparatus.
This current issues in a jet and the action of this jet draws in the other air with
which it is desired to cause its mixture according to the known method.
A similar method is employed in the Bunsen burner and the various forms of
construction which I have described as applicable for the mixture of gas and air
supplied to burners in the Specifications to Letters Patent granted to me on the
15th March 1876, No. 1108, and on the 24th Feb. 1877, No. 765, are applicable in
the present case.
The moderately cold current issuing from the mixture chamber is caused to
circulate through the chamber by suitable apparatus so as to produce pretty uniform
temperature at the degree of cold required.
The combination of apparatus previously explained, where a single cylinder
producing moderate refrigeration for the purpose of drying the air or fluid employed
is combined with a stage cylinder apparatus for producing intense cold, may also be
employed generally where it is desired to produce cold for any purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Matthew Piers Watt Boulton in the Great Seal Patent Office on
the 6th May 1879.
"IM-
MATTHEW PIERS WATT BOULTON, of Tew Park, in the County of Oxford.
PROVEMENTS IN THE MEANS AND APPARATUS FOR EFFECTING REFRIGERATION."
This Invention relates to means and apparatus for effecting refrigeration by the
expansion of compressed air or elastic fluid. One of its objects is to produce by
means of such apparatus an intense degree of cold much exceeding any hitherto
obtained by such means, and also to combine it with apparatus for effecting the
liquefaction of gases.
For effecting the compression employ the known method of stage pumping,
and the expansion by the similar known method of expanding by stages. The
pumps are worked by an engine; the air or fluid acting in the expansion cylinders
assists the engine. This combined apparatus for pumping and expanding by stages
will be spoken of by me as the stage cylinder apparatus.
For abstracting the heat of compression I avoid all internal injection of water.
It is important for the object aimed at to keep the interior of the apparatus per-
fectly free from moisture, because the congelation of this, by the evolution of latent
heat, greatly impairs the refrigerant action. I therefore abstract the heat of com-
pression solely by external agency of water or other cooling agent. Such a method
is frequently practised in the compression of air.
For like reason I perfectly dry the air or elastic fluid supplied to the pumps.
This drying may be effected by passing the fluid over or through chloride of
calcium, or sulphuric acid, or other known absorbents.
In some cases a mode of drying may be used, which I shall afterwards explain.
In the stage cylinders I employ each cylinder both for compression and expansion,
compression taking place on one side of the piston and expansion on the other.
The piston rod works on the side on which the compression - takes place. To
prevent passage of heat from one portion of the cylinder to the other, and to
protect the liquid which lubricates the piston from exposure to intense cold, the
piston is furnished with a shield on the side of expansion. This shield is so made
as to obstruct passage of heat, for which purpose various substances may be used.
Further, for the same object, the cylinder is made in parts, and vulcanite or some
substances which obstructs the passage of heat is placed in the joint.
The expansion cylinders are also covered or protected by some substance which
obstructs the passage of heat.
For the lubrication of the piston I consider that glycerine is suitable on account
of its slight volatility. It may if desired be protected from the action of the
warmth on the side of compression by a shield, and this may work on a part of the
cylinder kept at somewhat low temperature, where it can neither be frozen nor
give off any gaseous or vaporous matter.
The precautions above described are principally called for in those cylinders
in which on one side intense degree of cold exists, and are not so necessary in the
earlier stages, though not useless even there.
The air or elastic fluid on issuing from the final expansion cylinder passes into a
chamber, where it exerts refrigerant action in any manner desired. After having
done this it passes back to the first pump and is again subjected to the stages of
compression and expansion.
The refrigerant air or fluid being thus continually used over and over again may
be employed in the refrigerant chamber at any pressure desired. I consider it
desirable for the purpose in view to use it at a high pressure, so that in virtue of its
greater density it may exert more powerful refrigerant action.
Also by the employment of high pressure air or fluid the bulk of the, cylinders and
moving parts in the refrigerant apparatus may be much reduced.

page_text: The refrigerating chamber is covered or protected by some substance which
obstructs the passage of heat.
Loss by leakage of the air or fluid employed is supplied by a pump. This in
some cases may be done by a hand pump occasionally worked, but it may with
advantage be done regularly by means of a feed-pump worked by the engine, the
supply to which is governed by the pressure within the refrigerated chamber. This
feed pump is supplied from a vessel or reservoir containing the air or fluid used in
the apparatus in a perfectly dry state.
When it is desired to produce a very intense degree of cold hydrogen may be
employed as the refrigerant fluid, because by carrying the operation far a degree of
cold may be attained at which air would liquefy.
When it is intended to liquefy a gas, then within the chamber cooled by the
refrigerant fluid a series of stage compression pumps is provided, and these are
supplied with the gas to be liquefied already cooled. The heat of compression
generated in these pumps is abstracted by the refrigerant fluid circulating through
the chamber in its course from the expansion cylinders to the compression pumps,
and the compressed gas operated on is delivered into a vessel cooled in a similar
manner.
It is well so to arrange the compression pumps that their piston rods work
within the refrigerating chamber, being driven by a crank shaft passing through
the chamber. Passage of heat through this shaft is obstructed by means of a joint,
with vulcanite or suitable material interposed between the pieces or flanges of the
'metal.
The better to effect the abstraction of the heat of compression a blower of any
suitable kind worked by the engine is provided within the refrigerating chamber
or in connection with it, and this causes a current of the refrigerant fluid to pass
round the cylinders in which the gas is compressed, and the tubes through which it
passes and the vessel or chamber into which it is delivered.
This vessel or chamber may be an arrangement of tubes or passages exposing a
large surface to the action of the refrigerant fluid. Many of the known forms of
heating and cooling vessels are applicable for this purpose.
When it is desired to produce very intense degrees of cold after the liquefaction
of a gas has been effected a further degree of cold may be attained by the evapora-
tion of the liquid.
In many cases in which refrigeration is needed the object aimed at is to produce
only a moderate degree of cold; for instance, to cool the air in a room or chamber
to a temperature not much below the freezing point.
In such a case it is not necessary to employ a high degree of compression and
expansion, and the use of stage pumping may be dispensed with. Nevertheless,
even in this case I consider it advantageous to produce an intense degree of cold in
the refrigerant air or fluid, and employ this to give the moderate degree of cold to
the air of the room or substance to be moderately cooled.
One mode of effecting this is to employ an apparatus such as above described,
and cause the air or fluid intensely refrigerated in it to act in a refrigerator or
cooling vessel, which cools the air or other fluid or matter which it is desired to
cool to a moderate degree.
The refrigerating chamber may, as mentioned previously, be one of the numerous
forms of vessels presenting large surface employed for heating and cooling
purposes.
When a room or chamber is cooled in this way the air cooled by the refrigerator
is caused to circulate through the chamber by any suitable apparatus, so as to
produce nearly uniform temperature in the chamber, and so in other cases where it
is desired to cool fluid in like manner.
The air issuing from the refrigerator may be deprived of its moisture by any
known method. The following is one method which I employ
I cause the cold air to pass through a saline solution at low temperature. It is

page_text: caused to pass through the liquid in small bubbles; sheets of wire gauze or per-
forated material may be employed to effect its subdivision.
In passing through the saline solution at low temperature the snow suspended in
the air is liquefied and detained. As the solution becomes weaker by liquefaction
of the snow more salt is added.
The cold saline solution thus obtained may in some cases be used for refrigerant
purposes.
The salt can always be obtained from it again by boiling, and the distilled water
utilised.
Otherwise the cold air which it is desired to dry may be caused to pass in contact
with surfaces saturated with the saline solution.
The method of drying above described may also be employed to dry the air or
fluid employed in the refrigerating apparatus. For this purpose a single cylinder
which compresses and expands to a moderate degree, and produces a moderate
degree of cold, is combined with an apparatus of successive or stage cylinders,
which produces great compression and expansion and an intense degree of cold.
Air is first passed through the first mentioned apparatus and dried, as previously
explained, and the air so dried and moderately refrigerated supplies the stage
cylinder apparatus, and is intensely refrigerated therein.
By the application of this method the air of a chamber which it is desired
moderately to refrigerate may be passed directly through the stage cylinder appa-
ratus without the intervention of the refrigerator, as in the method previously
explained.
The intensely cold current of air issuing from the stage cylinder apparatus is not
allowed to issue directly into the room or chamber, but is passed first into a vessel
in which it mixes with a further portion of air supplied from the chamber, the
mixture being thus brought to a moderate degree of cold, and the moderately cold
current issuing.from this vessel is caused to circulate through the room or chamber
by means of any suitable known apparatus.
The mixture of the intensely cold air with the further portion of air may be
effected in various ways. The current of the less cold air may be produced by a
separate instrument, and injected by means of this into the chamber, into which
the stream of intensely cold air issues from the refrigerating apparatus.
But I consider it advantageous to dispense with the separate instrument and
effect the mixture by means of the pressure which impels the intensely cold current
in its issue from the stage cylinder apparatus.
This current issues in a jet, and the action of this jet draws in the other air with
which it is desired to cause its mixture according to the known method.
A similar method is employed in the Bunsen burner, and the various forms of
construction which I have described as applicable for the mixture of gas and air
supplied to burners in the Specifications to Letters Patent granted to me on the
15th March 1876, No. 1108, and on the 24th Feby. 1877, No. 765, are applicable
in the present case.
The moderately cold current issuing from the mixture chamber is caused to cir-
culate through the chamber by suitable apparatus so as to produce pretty uniform
temperature at the degree of cold required.
The combination of apparatus previously explained, where a single cylinder pro-
ducing moderate refrigeration for the purpose of drying the air or fluid employed
is combined with a stage cylinder apparatus for producing intense cold, may also
be employed generally where it is desired to produce cold for any purpose.
The accompanying Drawing represents a longitudinal section of one form of
apparatus for effecting refrigeration as above-described. It consists of three
cylinders A', A2, A3, of which A2 has less area than A¹, and A³ has less than A².
Each cylinder is made in two parts, the upper part bored true and fitted with a
piston B1, B2, B³, packed in any known manner. The lower part of each cylinder
C', C2, C3, does not require to be bored true, each piston having a shield D', D², D³,
which works in without fitting the lower part of the cylinder. The two parts of

page_text: each cylinder are separated by a layer of non-conducting material E, the upper
parts of the cylinders are surrounded by water contained in a tank F, the lower
parts are encased with non-conducting material G, and there are separate air
chambers H1, H2, H3, H4, on each side of these lower parts. The cover of each
cylinder is formed with air chambers provided with suction valves S¹, S³, S³, and
discharge valves V1, V2, V3. The air chamber containing the valve V₁ commu-
nicates with that containing S2 by a passage K¹, which is surrounded by the water,
and which may also have water tubes passing through it, as shewn, so as to expose
considerable cooling surface. Similarly, the chamber of V2 communicates with that
of S3 through K, and the chamber of V³ communicates by K³ with the lower
chamber H. The lower parts of the cylinders are provided with ports governed
by slides L, L2, L³, L, L, L, which may be worked, as shewn, by eccentrics or
cams from a countershaft M driven by any suitable gear at equal speed with a
crank-shaft, to which the pistons of the three cylinders are connected by connecting
rods in the usual. way. The chamber H¹ communicates by a pipe with the lower
part of the refrigerating chamber N, and the upper part of this chamber commu-
nicates by a pipe with the supply chamber of the cylinder A'. The crank shaft to
which the pistons are connected and the countershaft M being caused to revolve,
the pistons B1, B2, B3, are caused to reciprocate in their respective cylinders, and
also the slides L¹, L², L3, L4, L, L, are caused to move up and down so as to cover
and uncover their respective ports, being timed suitably to the strokes of the
pistons. Air or other gas is drawn from the chamber N into the cylinder A³, and
discharged therefrom into the vessel K¹, where it is cooled; thence it is drawn into
A², and discharged into K2, where it is again cooled. From K³ it is drawn into A³,
and discharged thence through K³, being cooled in its passage to H. From H* it
expands in C³ as the piston makes its upstroke, and is delivered during the down-
stroke into H³. In like manner it passes through C2, H2, C1, and H³, returning into
N, whence it again circulates through the successive pumps and cylinders, the heat
of the successive compressions which it undergoes being taken up by the water
of the tank F, and refrigeration being produced by its successive expansions in the
lower parts of the cylinders. The apparatus is shewn in the Drawing as being
encased in brick work or masonry in order to give it stability as well as to diminish
conduction and radiation of heat. It might however for this purpose be cased in
other imperfectly conducting material. Though three successive pumps and
expansion cylinders are shewn in the Drawing there might obviously be a greater
or less number of these, effecting the compression and the expansion of the fluid by
successive stages.
Having thus described the nature of the said Invention, and in what manner the
same is to be performed, I claim,-
-
First. Effecting refrigeration by compressing air or other gas by stage pumping,
abstracting the heat of compression by surface cooling, then permitting the
compressed fluid to expand by stages, performing work substantially as herein
described.
Second. In apparatus for treating air or gas in the manner referred to in the
preceding claim, employing the same cylinders for compression and for expansion of
the fluid, substantially as herein described.
In witness whereof, I, the said Matthew Piers Watt Boulton, have hereunto
set my hand and seal, this Fifth day of May, in the year of our Lord One
thousand eight hundred and seventy nine,
M. P. W. BOULTON. (L.S.)