IMPROVEMENTS. IN THE PROCESS *FOR REFRIGERATING OR COOLING AIR TO VERY LOW TEMPERATURES '
Year: 1883

page_text: LETTERS PATENT to George Herbert Lloyd of Birmingham in the County
"
of Warwick for an Invention of IMPROVEMENTS. IN THE PROCESS *FOR
REFRIGERATING OR COOLING AIR TO VERY LOW TEMPERATURES
'
I
PROVISIONAL SPECIFICATION left by the said George Herbert Lloyd at
the Office of the Commissioners of Patents on the 17th March 1883.
GEORGE HERBERT LLOYD of Birmingham in the County of Warwick
"IMPROVEMENTS IN THE PROCESS FOR REFRIGERATING OR COOLING AIR TO VERY
LOW TEMPERATURES
"2.
My invention has particular reference to improvements in the process for
refrigerating or cooling air to very low temperatures for the purpose of preserving
meat and other articles and for other purposes of manufacture and it relates to
both the machinery or processes i.e to that kind in which the air is first compressed
and raised in temperature and after abstracting the heat of compression it is cooled
by expansion. It also relates to those processes which cool air by passing it through
coolers in which the refrigerating medium has been cooled by vaporization of any
condensible gas.
I compress the air in such a manner as to give it a temperature such as may be
imparted to the condensing medium in the ordinary way. I then pass it through
coolers such as those mentioned in Barker's Patent N° 605 A.D 1882 thus cooling
it down to approximately the temperature of the condensing medium. I then pass
it through another cooler or set of coolers in which the cooling medium may be the
spent air from the cold store. I next pass it through a cooler or coolers in which
the cooling medium shall have been previously cooled by vaporization of ammonia
or other condensible gas. I am enabled by this process to cool the air while under
compression to a low temperature after which I expand it behind a piston or
otherwise and thus obtain a further very great decrease of temperature.
When using machines which cool the air by contact with surfaces cooled by a
cooling medium and cooled by vaporization of a condensible gas, I propose to cool

page_text: the air after having previously compressed it, and the cooling medium in the coolers
may either be water, spent air from the chamber, and then brine or other medium
previously cooled so as to reduce the temperature to a low degree while under
compression. By this means the very low temperatures required are obtained by
the final expansion of the air and the cooling medium has thus not to be cooled to 5
the lowest temperature required for air.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Herbert Lloyd in the Great Seal Patent Office on the
17th September 1883.
GEORGE HERBERT LLOYD of Birmingham in the County of Warwick
"IMPROVEMENTS IN THE PROCESS FOR REFRIGERATING OR COOLING AIR TO VERY.
LOW TEMPERATURES
"
My invention has particular reference to improvements in the process for
refrigerating or cooling air to very low temperatures for the purpose of preserving
meat and other articles and for other purposes of manufacture and it relates to both
the machinery or processes, i.e to that kind in which the air is first compressed and
raised in temperature and after abstracting the heat of compression it is cooled by
expansion. It also relates to those machines and processes which cool air by passing
it through coolers in which the refrigerating medium has been cooled by vaporiza-
tion of any condensable gas. I compress the air in such a manner as to give it a
temperature such as may be imparted to the condensing medium in the ordinary
way. I then pass it through coolers such as those mentioned in Barkers Patent
.No 605 A.D 1882 thus cooling it down to approximately the temperature of the
condensing medium. I then pass it through another cooler or set of coolers in
which the cooling medium may be the spent air from the cold store. I next pass it
through a cooler or coolers in which the cooling medium shall have been previously,
cooled by vaporization of ammonia or other condensable gas. I am thus enabled
to cool the air while under compression to a low temperature after which I expand
it behind a piston or otherwise and thus obtain a further very great decrease of
temperature. By this means the very low temperatures required are obtained by
the final expansion of the air and the cooling medium has thus not to be cooled to
the lowest temperature required for air..
In order that my invention may be more readily understood and carried into
practice I have appended hereunto a sheet of drawings which will serve more
clearly to illustrate the process.
Figure 1 is an elevation of an arrangement of an Air Compressor, Steam Engine,
Vacuum and Compression Pump; Condensing and Cooling vessels and Expansion
Engine with the necessary Circulating Pumps and pipes in connection.
Figure 2 is a plan of the arrangement represented in Figure 1.

page_text: A Figure 1 and 2 is the Steam Engine working the air compressor B, the vacuum
and compression pump C, the brine pump D and the water circulation pump E.
F Figure 1 and 2 is the Expansion Engine in which the cooled compressed air is
expanded. G is the Vaporizer in which the brine is cooled before passing to the
cooler K. H is the Gas Condenser in which the gas is liquified after having been
vaporized and expanded in the vaporizer G. I is a Multitubular Cooler through
which the air is passed after having been heated by compression in the compressor B
and is cooled by means of a circulation of water or other fluid. J is a multitubular
cooler through which the compressed air is next passed and still further reduced in
temperature by means of a circulation of non-congealable liquid which has been
reduced in temperature by the vaporization of any suitable liquid in the vaporizer G.
F is the Expansion Engine in which the compressed cold air in passing from the
cooler K is allowed to expand; M is the induction pipe for the air from the cold
chamber into the compressor B; N is the discharge pipe for the compressed air
from the compressor B to the coolers I, J, and K; O is the induction pipe for the
cooled compressed air from the cooler K to the expansion engine. P is the delivery
pipe from the circulating pump E to the cooler I and liquifier or condenser H.
Qis the induction pipe from the cooler K to the brine pump D. R is the delivery
pipe from the brine pump D to the vaporizer G and thence to the cooler K. S is
the induction pipe for the condensable gas from the vaporizer G to the vacuum and
compression pump C. T is the delivery pipe for the compressed gas between
compressor C and liquifier or condenser H. U is the delivery pipe for cold air in
the cold room.
In machines for mechanical refrigeration by what is known as the cold air
compression process the power required for compression and the subsequent ontlay
of fuel as is well known is excessive, and on the other hand in those machines in
which the condensable gasses are employed to cool air many disadvantages present
themselves. Now my invention has for its object the obtaining a greater degree of
cold by the same or a less expenditure of fuel-thus reducing the bulk of the
apparatus required to produce a given efficiency and to obtain with a moderate and
easily worked compression a range of low temperatures which have hitherto by
other processes been unobtainable.
I will now explain how the process may be carried out with reference to the
drawings:-
The atmosphere is drawn from the chamber to be cooled by the compressor B
and there compressed until the temperature is raised sufficiently above that of the
fluid which it is intended to use in the cooling medium I. It will be obvious
that the greater the difference in temperature between the air and the cooling
medium (water or other fluid) the more heat will be abstracted.
.
The compressed air is forced by the compression through the pipe N into the
cooler I, and it is there reduced in temperature as nearly as possible to the
temperature of the cooling medium. The air then passed on into cooler J where
it is brought in contact with surfaces already reduced in temperature by the cold
air returning from the chamber to the compressors by means of the pipe M. A
further cooling of the compressed air is thus secured. It then passes on to the
cooler K where it passes over surfaces reduced to a lower degree by the vaporization
of either ether, ammonia or other condensable gases; a further cooling is thus
obtained to a temperature far if required below the previous cooling medium. The
air still under compression is next passed into the expansion engine F by means of
the pipe and is there allowed to expand behind a piston causing thereby its
further proportionate reduction in temperature. It can then be passed into the
chamber which it is required to cool. By a very simple arrangement of pipes,
brine from the condensable gas machine may be made to circulate through the
chamber itself and thus-keep down the temperature in case of a stoppage of the
air compressing machinery. This process is a combination in part of two old and
well known systems of cooling by which a great advantage can be obtained over
the compression system (which first compresses cools with natural water or spent:

page_text: air and then expands) as the same cooling effect can be produced by a lower
compression or a smaller compression pump or less bulk of air.
Also by my process a great advantage in cooling air can be obtained over any
previously used system of cooling air by means of the vaporization of condensable
gases as the final cooling of the air is the result, not of conduction, but of a sure
and certain mechanical action and the final temperature of the air being much
lower by this means than its condensing medium the condensable gas is vaporized
at a much higher temperature and consequently at a much higher pressure and
therefore a smaller vapor pump and less power will vaporize an equal weight of
gas and produce an equal cooling effect. It is obvious that there are many other
advantages which can be obtained by using this process such as the increased range
of temperatures obtainable in a given sized machine. This should render such
machines suitable for travelling through various climates on board ship as without
increase of compression a great increase of cooling effect can be obtained by
reducing the cooling, medium in the last cooler at only a comparatively small
increase in consumption of fuel. There.would also by this process be a diminished
risk of waste of cooling effect by conduction to the atmosphere and surrounding
substances as during almost the whole process of its cooling the air is comparatively
at a high temperature, the low temperature being obtained suddenly at the end of
the operations and may be in close proximity to the cold chamber. The air can
also be almost entirely deprived of its moisture before expansion; there would
therefore be little or no danger of. formation of ice and snow in an expansion
cylinder a constant source of difficulty in ordinary compressed air machines, and
even if it is desired to cool the compressed air in the second or third cooler below
freezing point there would be a greatly diminished risk of the tubes being
stopped by snow or ice as the air is in a state of less relative humidity
or drier
The before mentioned advantages will serve to further illustrate the process but
they by no means exhaust the advantages obtainable.
It is obvious that almost any kind of air compressor and many arrangements
of coolers can be used but by preference I would employ those in Barker's Patent
before mentioned.
It is evident also that refrigerating machines using any of the condensable gases
can be used in my process. I should use in preference machines vaporizing ether,
ammonia or anhydrous sulphuric acid such as have been used by Harrison, Siebe,
Linde and others.
This process may be also adopted as. a reserve of power to an ordinary
compressed air machine and may be cut off from the machine and only worked
when an increase in the cooling effect is required or for more speedily cooling the
room down from the atmospheric temperature or when by reason of an accident a
lower compression is necessary and even if the air compression part of the machine
broke down altogether if arrangement had previously been made to do so, the
brine from the condensable gas machine could be circulated through the chamber
and keep it below freezing point.
It will be clearly understood that one or more coolers in sections or separate can
be employed and though I prefer coolers as described in Barker's Patent aforesaid
still the first cooler might be one in which water was in actual contact with the
compressed air and the last cooler might be actually the refrigerator of a
condensable gas refrigerating machine and the condensable gas machine might be
an absorption machine and not a compression machine as shown on the drawings
without interfering with the process described. I do not confine myself therefore
to any air compressor or cooler or refrigerating machine nor to any system of air
compressing cooling and refrigerating nor do I wish to limit myself to the precise
details herein described, but I claim :-
:-
First-In air cooling by compression cooling and subsequent expansion the
novel process of passing the air while under compression through a. cooler in.

page_text: which the cooling medium has been previously cooled by vaporization of a
liquified gas.
Second-In air cooling when the cooling medium has been previously cooled by
the vaporization of a liquified gas the novel process of cooling the air below the
coldest cooling medium by compression previous to such cooling and expansion
subsequent to it in the manner described.
Third-In air cooling the novel process of passing the compressed air during
the same process of cooling through coolers or sections of a cooler the cooling
medium in one section being natural water or spent air or both and in another
section brine or a medium cooled by vaporization of a liquified gas.
Fourth In cooling air by a medium which has been cooled by vaporization of
a liquified gas the novel process of depriving the air of some portion of its
moisture in the manner described previously to being cooled by the medium before
mentioned.
:-
Fifth The novel process of cooling air substantially as herein-before described
and illustrated on the accompanying drawings.
In witness whereof I, the said George Herbert Lloyd have hereunto set my
hand and seal this thirtieth day of August in the year of our Lord one
thousand eight hundred and eighty three.
CHOPA
TERRERT LLOVD
Gra