IMPROVEMENTS IN THE METHOD OF AND MACHINERY OR APPARATUS FOR PRODUCING ARTIFICIAL COLD AND ICE
Year: 1871

page_text: LETTERS PATENT to Alphonse Louis Normandy, of No. 35, Albert
Square, Clapham Road, in the County of Surrey, for the Invention
of "IMPROVEMENTS IN THE METHOD OF AND MACHINERY OR APPARATUS
FOR PRODUCING ARTIFICIAL COLD AND ICE."
Scaled the 16th June 1871, and dated the 20th April 1871.
PROVISIONAL SPECIFICATION left by the said Alphonse Louis Nor-
mandy at the Office of the Commissioners of Patents, with his
Petition, on the 20th April 1871.
I, ALPHONSE LOUIS NORMANDY, of No. 35, Albert Square, Clapham
Road, in the County of Surrey, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE METHOD OF AND MACHINERY OR APPARATUS
FOR PRODUCING ARTIFICIAL COLD AND ICE," to be as follows:-
These improvements relate to the method of producing cold by the
alternate compression and expansion of atmospheric air or other suitable
gas by mechanical means without the necessity of reducing such gas to
the liquid form either by compression, cold, or by solution.

page_text: Hitherto in machines working according to this method it has been
usual to compress common air in a cylinder of suitable size, the heat
evolved by such compression being partially absorbed by a water jacket
round the cylinder, but principally by the hot compressed air after it has
left the cylinder being brought in contact with extensive surfaces cooled
by a current of cold water, and by causing the compressed air when thus
cooled to pass into an expansion cylinder where it is allowed to expand
back to atmospheric pressure, thereby restoring some of the motive
power used to compress it, while the air in so expanding becomes so
intensely cold that after leaving the expansion cylinder it could be
employed to freeze water or produce other cooling effects such as the
separation of parafline.
In such machines also it has been usual for the compressing cylinder
to draw in air at atmospheric pressure and to compress it into about
one-fourth of its volume, thereby increasing its pressure to about 45 lbs.
per square inch, and this compressed air was afterwards expanded back
to about atmospheric pressure in the expansion cylinder before it was
discharged therefrom for use for cooling purposes, hence such machines
are necessarily bulky and expensive for a comparatively small production
of cold.
Now according to my present Invention I so compress the common
air or other gas that the heat evolved by compression is absorbed almost
as fast as it is produced, the compressed air therefore never rising more
than a few degrees above its original temperature, and I furthermore so
expand the compressed air that the cold produced during expansion is
utilized nearly as fast as it is produced, the expanded air therefore never
falling more than a few degrees below the degree of cold it is desired to
produce. By thus compressing the air I diminish tho loss of motive
power, which in machines of present construction is stored up in the
form of heat in the compressed air and is lost on its discharge from the
compressing cylinder, and by thus expanding the compressed air I
obtain an increased return of the motive power due to the heat absorbed
by the air during expansion, instead of allowing it to expand so as to
become intensely and uselessly cold as in other machines.
The essential features of my Invention for carrying out the before-
mentioned objects consist, firstly, in effecting the compression and
expansion of the air or other gas when contained in a divided state
inside passages having extended surfaces through which heat readily

page_text: passes from and to every portion of the air to and from a fluid or
gas surrounding the passages, secondly, in effecting the compression.
and expansion of the air in such passages by forcing into them and
withdrawing therefrom a suitable fluid by the agency of a cylinder and
piston, instead of effecting the compression and expansion directly by a
cylinder and piston as heretofore.
Also according to another essential part of my present Invention
instead of compressing and expanding air from and to atmospheric
pressure as has heretofore been done I compress and expand it from
and to a much higher pressure, thus greatly increasing the cold pro-
ducing power of the machine employed without increasing its size.
I prefer to carry out the above described methods of operating by
means of the following arrangements :-Instead of admitting the air to
be compressed into a compressing cylinder as hitherto done I admit it
into a number of small compression tubes communicating at their lower
ends with a compression cylinder filled with a suitable liquid (by prefer-
ence glycerine or what is known commercially as "glycerinum") and
arranged so that the advance of a piston in the compression cylinder
forces the liquid up the compression tubes, thereby compressing the air
contained in them, and eventually expelling it in a compressed state
through an outlet valve communicating with the upper ends of these
tubes into a compressed air reservoir. On the retreat of the piston the
liquid flows back from the compression tubes so that they may become
again charged with air admitted into them through a suitable inlet valve
also communicating with their upper ends, which further supply of air
is again compressed and expelled by the advance of the compressing
piston as before described. These compression tubes are cooled by a
current of cold water or even air circulating outside of them so that the
heat evolved by the compression of the air inside the compression tubes
is absorbed almost as fast as it is produced, hence the compressed air
never rises more than a few degrees above its original temperature or
that of the circulating water or air surrounding it.
Furthermore, instead of admitting the cooled compressed air into an
expansion cylinder as was hitherto done, I admit it into a number
of small expansion tubes containing a suitable liquid (by preference
glycerine or glycerinum), and communicating at their lower ends with
an expansion cylinder also containing this liquid, and arranged so that
by the retreat of the expansion piston the liquid is caused to flow from

page_text: the expansion tubes into the cylinder, while simultaneously a portion
of compressed air from the compressed air reservoir is admitted into these
tubes by a suitable inlet valve communicating with their upper ends,
and arranged so as to cut off the supply of compressed air at any desired
point of the retreat of the piston and fluid. By the continued retreat
of the expansion piston and fluid, after the cutting off of the supply
of air, such air is caused to expand in the expansion tubes, thereby
producing cold, which cold rapidly absorbs heat from the air or liquid
surrounding the outsides of the expansion tubes, which surrounding air
or liquid thereby becomes cold, and may, if desired, be applied to cool
other things or to produce ice. After the compressed air is expanded in
the expansion tubes it is expelled by the advance of the expansion piston,
again forcing the liquid up these expansion tubes, and the expanded
air is discharged through a suitable outlet valve communicating with
the upper ends of these tubes into an expanded air reservoir, from
whence it is withdrawn to supply air to the compression tubes to be again
compressed therein as before described. By thus expanding the com-
pressed air in expansion tubes its temperature never falls much below
that of the air or liquid surrounding the outside of them, and docs not
therefore become intensely and uselessly cold as in machines heretofore
employed; and the heat absorbed by the air during expansion from the
air or liquid to be cooled is therefore nearly all usefully employed,
thereby enabling cold to be produced by mechanical means, for a small
expenditure of motive power, and therefore at a small cost.
Another advantage arising from the employment of a fluid to effect
the compression and expansion of the air or other gas, instead of using
a piston to act directly upon the air for this purpose, consists in the
diminution of leakage past the piston, and consequent prevention of loss
of useful effect, and also in the effectual lubrication of the piston by
such fluid.
To obtain the advantage of a large production of cold, with a com-
paratively small machine, I adopt a small air pump which forces air
into the chamber from which the compression tubes are supplied, so as
to compress the air therein to any desired pressure before it is admitted
into the compression tubes, which tubes therefore become filled with
air at a considerable pressure before this air is further compressed
in and discharged from them at a still higher pressure into the com-
pressed air reservoir, from which the expansion tubes are supplied; and

page_text: the expansion tubes being supplied with this highly compressed air only
expand it back to about the pressure of the air in the reservoir supplying
the compression tubes, into which reservoir also this expanded air is
discharged to be again compressed as before described. After the supply
reservoir for the compression tubes is once charged with air at the
desired pressure, the small air pump is only used for the purpose of
compensating for any small loss by leakage which might occur, in order
to prevent the minimum pressure from falling too low. By this com-
pressing and expanding air or other suitable gas from and to a minimum
pressure much higher than atmospheric pressure, the refrigerating
power of the machine is greatly increased, and the higher the minimum
pressure is the greater will be the increase, even though the relative
volumes of the air in the compression tubes before and after compression
remain unchanged; hence by this plan considerable effects are produced
with comparatively small machines, without the necessity of a great
variation in the minimum and maximum volumes of the air operated
upon, which in practice is attended with many difficulties. As common
air contains more or less moisture, which might freeze in the machine
and impair its action, I prefer to cause the air to be operated upon to
pass over or through some substance which readily absorbs moisture
(by preference fused chloride of calcium) before entering the machine.
When it is desired to utilize the still low temperature of the
expanded air as it flows from the expansion tubes, I prefer doing so
by surrounding the reservoirs containing the compressed and expanded
air by the same body or bodies of water, so that this water shall abstract
heat from the compressed air in the compression reservoir or reservoirs,
and which is about to be expanded, and shall impart it to the expanded
air in the expansion reservoir or reservoirs, and which is about to be
compressed, thus approximating the temperature of the air admitted
to the compression and expansion tubes to the respective temperatures
of these tubes. This arrangement is desirable, for when the air is
admitted into the tubes it becomes of about the same temperature as
these tubes as fast as it is admitted; and therefore in the expansion
tubes a portion of the cold would otherwise be uselessly absorbed from
the surrounding liquid, and in the compression tubes a portion of the
cold would be uselessly dissipated by the surrounding liquid.
I prefer to fit the compressing and expanding pistons with cup
leathers, and to face all the inlet and outlet valves with leather, as also
to fit the piston rods and valve rods with hydraulic pump leathers, all

page_text: being kept tight and lubricated by the pressure, and a suitable fluid, by
preference glycerine, or what is known in commerce as "glycerinum,"
which is less expensive than pure glycerine. I prefer making the valves
so as to open against the pressure, and to actuate the expansion tube
valves by means of suitable cams on way shafts, receiving motion from
the crank shaft of the machine. I also prefer placing the compression
and expansion cylinders opposite to each other, their pistons being fixed
on the same piston rod to which the motive power is applied by a
cross head and connecting rod from the crank shaft, so as to cause it
and its two pistons to reciprocate and actuate the fluid with which the
compression and expansion cylinders and tubes are charged as before
described. I prefer also to make the compression and expansion
cylinders double acting, so that the pressure in acting alternately on
both sides of the pistons would tend to equalize any slight leakage past
the pistons, and would thus maintain the right quantity of fluid in the
expansion and compression tubes; and when necessary more fluid may
be added so as to insure this, which is important in order to properly
compress and expand the air in the expansion tubes. I prefer also to
cover the upper ends of the compression and expansion tubes with
perforated plates, through which the air is made to pass, so as to
promote a steady flow of air to and from all the expansion and com-
pression tubes.
When it is desired to surround the the expansion tubes with a fluid
intended to be cooled, so that it may be employed to cool other things,
I prefer using glycerine or glycerinum as the surrounding fluid, as this
substance is not liable to freeze or dry up readily, for which reasons I
also prefer it for the applications before described.
Although I prefer to employ tubes of a small diameter, as before
described, for the passages in which is effected the compression and
expansion of the air, yet it will be evident that such passages may also
be otherwise constructed for affording the requisite extended surfaces
for the passage of heat to and from the air when in a divided state;
thus, for instance, they may be constructed of concentric cylinders,
forming narrow annular passages surrounded on the inside and outside
by the fluid or gas for taking up and giving off heat. Also, although I a
prefer to effect both the compression and the expansion of the air,
according to the method herein-before described, yet it will be evident
that this method may be applied to the compression of the air alone,

page_text: or to the expansion of the air alone, without its being of necessity
applied to both operations in combination.
Instead of double-acting pistons for the compression and expansion
cylinders, single-acting plungers may be used, or one single piston may
be made to act in one cylinder, compressing on one side and expanding
on the other, such piston being made of a material that is a bad con-
ductor of heat, but I prefer the separate double-acting pistons as before
described.