IMPROVEMENTS IN PRE- SERVING MEAT, AND IN APPARATUS EMPLOYED THEREIN
Year: 1867

page_text: LETTERS PATENT to William Mort, of No. 155, Fenchurch Street, in the
City of London, Merchant, for the Invention of "IMPROVEMENTS IN PRE-
SERVING MEAT, AND IN APPARATUS EMPLOYED THEREIN."-A communication
from abroad by Thomas Sutcliffe Mort, residing at Green Oaks, near
Sydney, New South Wales.
Sealed the 15th May 1868, and dated the 23rd November 1867.
PROVISIONAL SPECIFICATION left by the said William Mort at the
Office of the Commissioners of Patents, with his Petition, on the 23rd
November 1867.
I, WILLIAM MORT, of No. 155, Fenchurch Street, in the City of London,
Merchant, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PRESERVING MEAT, AND IN APPARATUS EMPLOYED THEREIN," to be as
follows:-
This Invention, being an application of Faraday's discovery of the liquefaction
of certain gases by pressure, and the capacity of such gases for the absorption
of heat on their release from liquefaction has for its object the introduction of
improved mechanical arrangements whereby such gases may be employed to
A

page_text: produce a temperature sufficiently low to secure the preservation of all articles
of food.
Although other liquefying gases may be used it is proposed to work the
apparatus by means of ammoniacal gas, which by reason of its great solubility
in water, and of the quantity of calorice which it absorbs in passing from the
liquid to the gaseous state, and on account of its safety for use on shipboard,
appears to be the most suitable agent to employ.
The apparatus consists of, 1, a metallic vessel called the separator. 2, a
Liebig's condenser. 3, an apparatus called desiccator, consisting of several
spiral coils immersed in a bath through which a constant stream of cold water
is kept running. 4, an apparatus called the liquefying coil, made to offer a
large cooling surface to the desiccated gas. 5, a metallic vessel called the
liquefied gas receiver. The liquefying coil and the liquefied gas receiver are
immersed in a bath common to both through which a current of cold water is
kept flowing. 6, a metallic vessel called "the feeder;" this vessel is also
immersed in a bath having cold water running through it. 7, a wooden vat
called a cooler, containing a small metallic coil immersed in running water.
This coil is so arranged that the water at each turn of the coil is kept at a
different cooling temperature. The hot water is removed at the surface, the
cold water being introduced at the bottom of the vat. 8, another cooler con-
structed similarly to the first. 9, a metallic vessel called the re-absorber. This
vessel is provided with a large internal coil of metallic piping through which
a constant stream of cold water is allowed to flow. After the internal refige-
ration has been effected the water escapes into a wooden vat surrounding the
re-absorber, from which it is permitted to flow freely. The re-absorber is
provided with level gauges similar to that of the separator hereafter described
to mark the rise and fall of the liquid within. 10, metallic vessels made in
any suitable shape to receive the articles of food to be preserved, and called
the meat receivers. The meat receivers are made with a double casing to
form a compartment having its walls perfectly tight to contain liquefied gas.
This vessel is surrounded by some good non-conducting substance, as charcoal,
felt, or gutta percha, enclosed in a wooden covering painted or varnished to
exclude moisture. The two shells should be placed eccentric to each other,
so that the inner shell will rest upon the bottom of the outer one, leaving at
the top a space of about two inches.
The practical operation is commenced by forcing into the separator the
re-absorber and the feeder the liquid ammonia of commerce, and the first
operation is to expel the air from the apparatus and to rectify the ammonia.
The separator having been filled to two-thirds of its capacity with the aqueous

page_text: solution of ammonia, and the re-absorber having been supplied with the same
strength of the ammonical solution to two-thirds of its capacity; and, lastly,
the feeder having been similarly supplied to one-third of its capacity, steam is
admitted to the separator coil and heat is gently applied to the solution in the
separator, the condensed water being allowed to return to the steam boiler.
The ammoniacal solution immediately begins to give off gas, which filling the
spaces of the vessels and pipes of the apparatus drives before it all the air;
when all the air has been expelled the escape orifice is closed. The ammo-
niacal gas is now caused to pass from the separator by suitable conducting
pipes and cocks through the Liebig's condenser and the desiccator to a per-
forated pipe which distributes it amongst the solution in the feeder, thereby
greatly strengthening it. The aqueous vapour condensed in the desiccator
during the operation is returned to the separator. The beat in the separator
is gradually increased until the gas therein is nearly all exhausted. The gas
passage is now closed and cocks are opened, by which the weak liquor passes
to the coolers, and the weak liquor being cooled is removed from the appa-
ratus. The extraction of the weak liquor at this stage is to give an increased
quantity of absolute ammonia into the machine. This operation should be
repeated according to the number of vessels to be refrigerated for the pre-
servation of food. Being now ready for the liquefying operation the strength-
ened liquor in the feeder is allowed to run into the separator until the quantity
of liquid necessary for liquefaction is passed. Steam is again gradually
admitted as before through the coil of the separator. The communication
cock being opened a free current of gas takes place through the Liebig's con-
denser, the desiccator and the liquifying coil into the liquified gas receiver,
the steam is gradually increased until the liquifying pressure is attained, which
pressure is maintained until nearly the whole of the ammonia in the separator
is liquified. The feeder is now re-supplied with ammonical solution from the
re-absorber, and then the remainder of the ammoniacal gas contained in the
weak liquor in the separator is passed into the feeder in place of into the liqui-
fying coil, which operation effects the two-fold object of depriving the weak
liquor of its ammonia and of strengthening the strong solution in the feeder
when the gas is nearly exhausted; the weak liquor is forced through the
coolers into the re-absorber, being caused to enter as a shower into the gas
space in this vessel. To force the liquor out of the separator sufficient pressure
is generated to overcome the resistance offered by the gas in the re-absorber.
As soon as the weak liquor enters the re-absorber the pressure therein is
neutralized by the absorption of the gas by the weak liquor. The separator
being now empty another charge from the feeder is allowed to pass into it.

page_text: Now the liquified gas held in the gas receiver is passed into the gas com-
partment of the meat receiver. When the gas receiver is empty the operation
of liquifaction, as before fully explained, is resumed.
Everything is now ready for the production of cold, which is effected as
follows: A cock called the freezing cock connected with the gas compartment
of the meat-preserving vessel is opened and the gas in the said compartment
is allowed to escape by a perforated pipe into the weak liquor in the re-
absorber. The gas from the gas compartment of the meat receiver rushes out
with great violence, for it is still under its liquefying pressure, and there is a
partial vacuum in the re-absorber, and furthermore ammoniacal gas has so
great an affinity for water that at a temperature of 60 degrees Fahrenheit
water will absorb about 660 times its volume of ammoniacal gas; under such
circumstances the gas is re-absorbed and the liquor gradually restored to its
full strength prepared for re-liquifaction by the process already described.
During this operation the liquefied gas in the gas compartment of the meat
receiver losing its pressure immediately passes into the gaseous state and robs
the vessel in which it was confined and its contents of their heat. The cold
soon becomes intense and very low temperatures can be obtained. After each
liquefaction the gas compartment is replenished and the article of food in the
meat receiver is reduced to the degree of temperature desired, and such
temperature can be maintained by regulating the freezing cock, and thus
enabling the apparatus by its self-action to produce cold for days and weeks
without any further liquefaction. After repeated gasifications in the gas
compartment of the meat receiver a cold solution (being the result of the
imperfect desiccation of the gas) accumulates, of which it is necessary to purge
the gas compartment, which object is accomplished by shutting the freezing
cock and opening other cocks, the one admitting gas under pressure from the
liquifying coil and the other leading the liquor into the re-absorber. The right
time for this operation is when the re-absorber is in vacuum after the liqui-
faction is completed. The heat is applied to the separator by steam which
passes through a pipe superheated by the waste heat of the smoke box, the
flue, the funnel, or chimney of the steam boiler, to be condensed and returned
to the water space of the said steam boiler.
The liquids are conveyed from one part of the apparatus to another in the
following manners:-
First. The removal of the weak liquor left in the separator after the gas
has been driven off is effected by the pressure to be obtained by increasing
the beat in the coil inside the separator, the amount of which can be regulate.
by dhe steam admission cock. This heating forces the hot weak liquor through

page_text: the coolers until being thoroughly cooled it reaches the re-absorber, into which
it quickly enters, a partial vacuum having been produced by the immediate
absorption of ammoniacal gas.
Second. The removal from the re-absorber to the feeder of the liquor which
has been made into a strong concentrated aqueous solution by the re-absorption
of the gas from the vessels to be refrigerated is effected by borrowing pressure
from the liquifying coil by a suitable connection. On the application of this
gas pressure the liquid in the re-absorber is forced into the feeder through
the connecting pipe which is open for that purpose.
Third. The separator is refilled with the strong solution from the feeder,
although the pressure in the former vessel is greater than in the latter, by
allowing the excess of the pressure in the separator to pass through the feed
cock, and to ascend into the feeder, while at the same time the stop-cock
which controls the communication between the desiccator and the feeder is
open. An equal pressure in the two vessels is soon effected, and the
law of gravitation being free to act takes the liquid from the feeder to the
separator.
Fourth. The removal to the re-absorber of the cold aqueous solution which
constantly accumulates during gasification in the gas compartment of the
meat receiver is accomplished by borrowing gas pressure from the liquifying
coil by an arrangement similar to that already described in connection with
the removal of the strong liquor from the re-absorber.
This vessel, which
I also employ what I call the portable meat preserver.
is specially for use on short journeys or voyages, may however be substituted
for the meat receiver already described. The portable meat preserver is a
double cased metallic vessel of suitable shape placed inside a case or cask and
protected by some good non-conducting substance, such as charcoal or gutta
percha, packed between the wood and the metal. The object of this vessel is
to preserve articles of food in portable parcels, which is effected by forcing by
suitable contrivances through the narrow compartment between the two metal
walls a freezing liquid, such as a saturated solution of chloride of sodium or of
chloride of calcium, which does not congeal except at a very low temperature.
The freezing medium is introduced by a pipe at the lower or other part of the
vessel, and after having circulated through the liquid compartment of the
5 "portable meat preserver" it is allowed to escape by another pipe, carrying off
with it the heat contained in the substance to be preserved by refrigeration.
The heated liquid returns to that part of the apparatus from which it derived
The compart-
its low temperature to be again refrigerated for further use.
ment through which the freezing medium is made to circulate may be separated

page_text: into two spiral-shaped divisions, one of which should be filled with fresh water
to be frozen at the same time the food to be preserved is operated on through
the other division by the freezing medium. The object is to surround the
inner metallic portion of the portable meat preserver with a band of ice to
assist in maintaining at a low temperature the contents within.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Mort in the Great Seal Patent Office on the
22nd May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MORT, of No. 155, Fenchurch Street, in the City of London, Merchant, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of November, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Mort, Her special licence that I, the said William Mort,
my executors, administrators, and assigns, or such others as I, the said
William Mort, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
PRESERVING MEAT, AND IN APPARATUS EMPLOYED THEREIN," a communication
to me from abroad by Thomas Sutcliffe Mort, a person resident at Green
Oaks, near Sydney, New South Wales, upon the condition (amongst
others) that I, the said William Mort, my executors or administrators,
by an instrument in writing under my, or their, or one of their bands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Mort, do hereby declare the
nature of the said Invention, and in what manner the same is to be
per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-

page_text: The Invention being an application of Faraday's discovery of the liquifaction
of certain gases by pressure, and the capacity of such gases for the absorption
of heat on their release from liquifaction, has for its object the introduction of
improved mechanical arrangements whereby such gases may be employed to
produce a temperature sufficiently low to secure the preservation of all articles
of food.
Although other liquefying gases may be used it is proposed to work the
apparatus by means of ammoniacal gas, which by reason of its great solubility
in water, and of the quantity of caloric which it absorbs in passing from the
liquid to the gaseous state, and on account of its safety for use on shipboard
appears to be the most suitable agent to employ.
I now proceed to describe with the aid of the Drawings annexed the
mechanical arrangements by which the object of the said Invention can be
practically carried into effect.
Figure 1 represents a transverse sectional elevation of the apparatus, which
is exhibited as if placed on shipboard, although it will likewise be used on
land; Figure 2 represents a sectional plan of the mode of applying heat to
the separator; Figure 3 represents a sectional plan and sectional elevation of
an apparatus which I call the portable meat preserver; all the vessels,
pipes, and cocks which may come in contact with the liquid to be gasified
must be made of iron or other suitable material on which the gases will have
no destructive effect.
I commence by describing the main portions of the apparatus as seen in the
Drawing of Figure Number 1. A, a metallic vessel, called the separator, filled for
two-thirds of its capacity with a concentrated aqueous solution of ammonia;
B, a Liebig's condenser, to condense in great part the aqueous vapour and
reduce the temperature of the gas previous to its entering the dessiccator;
C, called the dessiccator, consists of several spiral coils immersed in a bath
through which a constant stream of cold water is kept running.
By this
dessiccator offering as it does a large cooling surface it is intended to complete
as far as possible without chemical agencies the desiccation of the gas before.
it enters the liquefying vessel, and by cold water to carry away the heat given
off during the said desiccation; D, called the liquefying coil, made to offer a
large cooling surface to the desiccated gas internally compressed to lique-
faction; E, a metallic vessel, called the liquefied gas receiver, into which the
liquefied gas passes from the liquefying coil D. These portions of the
apparatus are immersed in a bath common to both, through which a current
of cold water is kept flowing to remove the heat given off during liquefaction;
F, a metallic vessel called "the feeder," from which the concentrated aqueous

page_text: solution of ammonia is supplied to the separator A. This vessel is also
immersed in a bath baving cold water running through it to remove the heat
given off during the rectification which takes place after each successive
liquefaction; G, a wooden vat called a cooler, containing a small metallic coil
immersed in running water, having for its object the rapid cooling of the weak
ammoniacal liquor on its passage from the separator A to the re-absorber H.
This coil is so arranged that the water at each turn of the coil is kept at a
different cooling temperature. The hot water is removed at the surface, the
cold water being introduced at the bottom of the vat. This cooler removes
the bulk of the heat. G, G, also a cooler constructed similarly to the
cooler G, in which the cooling of the weak ammoniacal liquor is completed;
H, a metallic vessel called the re-absorber, into which the cooled weak
ammoniacal liquor is received to be re-saturated with ammoniacal gas.
This vessel is provided with a large internal coil of metallic piping, through
which a constant stream of cold water is allowed to flow to carry away the
beat given off during re-absorption of the gas. After the internal refrigeration
has been effect the water escapes into a wooden vat surrounding the re-
absorber H, from which it is permitted to flow freely to assist in maintaining
the ammonical solution in a cool state. The re-absorber is provided with
level gauges similar to that of the separator hereafter described to mark the
rise and fall of the liquid within. I, I, I, three or more metallic vessels made
in any suitable shape to receive the articles of food to be preserved, and
called the meat receivers.
It will only be necessary to describe one of those vessels, as the principle
on which they are all constructed is alike. The meat receiver is made with
a double casing to form a compartment, having its walls perfectly tight to
contain the liquefied gas supplied from the liquefied gas receiver E. This
vessel is surrounded by some good non-conducting substance, as charcoal, felt,
or gutta percha, enclosed in a wooden covering painted or varnished to
exclude moisture. The two shells of the cylinder should be placed eccentric
to each other, so that the inner shell will rest upon the bottom of the
outer one, leaving at the top a space of about two inches; a similar
arrangement can be applied to any other shape of meat receiver with a
double casing.
Having thus described the several main portions of my apparatus, I shall
proceed by Figures to explain the various detailed parts.
1, a level gauge provided with a glass tube, in order to ascertain the height
of the liquid in the separator A, and thus enabling the temperature necessary
for volatilizing the gas for liquefaction to be regulated, and in its turn

page_text: insuring the refilling of the separator with the strong solution to the proper
beight.
2, a steam cock, to admit steam into the internal coil of the separator A.
8, a metallic coil fixed inside the separator A to supply heat to the con-
centrated aqueous solution of ammonia.
4, a discharge cock, through which the condensed steam is returned into
the water space of the steam boiler.
5, a small pipe admitting water into the water space of the Liebig's
condenser.
6, a stop-cock for cutting off the communication when required between the
desiccator and the liquefying portion of the apparatus.
7, a branch pipe from the desiccator C to the feeder F.
8, a rectifying stop-cock to regulate the communication between the
desiccator and the feeder.
9, a stand pipe perforated at the extreme end with minute holes, and
attached near the bottom of the feeder F and plunged into the ammoniacal
solution contained therein.
10, a feed pipe connecting the lower part of the feeder F with the top of
the separator A.
11, a stop-cock to admit the ammoniacal solution when necessary into the
separator from the feeder.
12, the weak liquor discharge pipe from the lower part of tho separator A.
This pipe carries the weak liquor through the coils of the coolers G and G, G,
into the re-absorber H.
13, 130, two stop-cocks to close the connection between the separator and
the re-absorber, 13° being a two-way cock.
14, a perforated tubular ring fixed internally in the upper part of the
re-absorber II, for distributing the weak liquor in fine jets, thereby enabling
the gas contained under pressure in that vessel to be re-absorbed and the
pressure neutralized.
15, a downward pipe branching from the junction of the Liebig's condenser
with the desiccator to return the condensed aqueous vapor to the separator A,
to mix with the hot liquor, that the gas brought with it may be re-volatilized.
16, a pipe connecting the lower part of the liquefied gas receiver E with
the meat receiver I.
I would here remark that in the Drawing of the transverse sectional
elevation of my apparatus (Figure number 1) I have shown a cross branch
pipe representing the connection between the gas compartments of the various
meat receivers to be extended as the vessels to be refrigerated are multiplied.

page_text: I have only described the refrigerating operation as applied to the double
cylinder in the centre of the ship, to avoid complication by mere repetition.
17, a stop-cock called the passing cock, to supply the meat receiver with
liquefied gas.
Before proceeding further with the detailed description of the apparatus I
think it better for a clear understanding of the modus operandi to point out the
means by which without the assistance of pumps or other external mechanical
appliances I am enabled to move the liquid from one vessel to the other, even
when at times there is a great pressure in the vessel into which the liquor is
to be conveyed opposing its entrance. My contrivances, by dispensing with
any external motive power to force the liquid from one vessel to the other, will
be found to provide a perfect security against any loss whatever of the gas
employed, and to ensure with the greatest certainty the removal of the weak
liquor from the separator and its return to the same saturated with the gas
which has been expelled from it.
First, the removal of the weak liquor left in the separator after the gas has
been driven off is effected by the pressure to be obtained by increasing the
heat in the coil inside the separator, the amount of which can be regulated
by the steam admission cock. This heat forces the hot weak liquor through
the coolers G and G, G, until being thoroughly cooled it reaches the re-
absorber, into which it quickly enters, a partial vacuum having been produced
by the immediate absorption of ammoniacal gas.
Second. The removal from the re-absorber to the feeder of the liquor which
has been made into a strong concentrated aqueous solution by the re-absorption
of the gas from the vessels to be refrigerated is effected by borrowing pressure
from the liquefying coil by a suitable connection to be described. On the
application of this gas pressure the liquid in the re-absorber is forced into the
feeder through the connecting pipe, which is opened for that purpose.
Third. The separator is refilled with the strong solution from the feeder,
although the pressure in the former vessel is greater than in the latter, by
allowing the excess of the pressure in the separator to pass through the feed
cock 11, and to ascend through the pipe 10 into the feeder, while at the same
time is opened the stop-cock 8, which controls the communication between
the desiccator and the feeder. An equal pressure in the two vessels is soon
effected, and the law of gravitation being free to act takes the liquid from the
feeder to the separator.
Fourth. The removal to the re-absorber of the cold aqueous solution which
constantly accumulates during gasification in the gas compartment of the
meat receiver is accomplished by borrowing gas pressure from the liquefying

page_text: coil by an arrangement similar to that already described in connection with
the removal of the strong liquor from the re-absorber.
I now continue the explanation of the details.
18, an internal pipe fixed near the bottom of the re-absorber H.
19, a stop-cock for controlling the connection between the re-absorber H
and the feeder F, which is established by the pipes 20 and 20° leading into
the feed pipe 10 which communicates with the feeder.
21 and 21°, the gasifying U-pipe which connects the gas compartment of
the meat receiver I with the re-absorber H.
22, a cock to regulate the production of cold.
23, an internal perforated pipe for diffusing the gas through the weak liquor
in the re-absorber H.
24, 240, 240, are three stop-cocks used in applying the pressure in the
liquefying coil D to the removal of the liquid from the re-absorber to the feeder,
and from the gas compartment of the meat receiver to the re-absorber.
25, a pipe branching on to the upper part of the liquefying coil D, and
communicating with the three stop-cocks 24, 24°, 2400; W, a pipe fixed in
the upper portion of the water compartment of the feeder, by which cold.
water is admitted from without to supply the several parts of the apparatus in
succession.
26, a downward pipe to take water into the lower part of the bath in which
the liquefying coil D and the gas receiver E are fixed.
27, also a downward pipe leading the cold water to the lower part of the
bath of the desiccator C.
28, an overflow pipe leading the water in the refrigerating coil fixed in the
re-absorber H.
29, an internal refrigerating coil fixed in the re-absorber.
30, the water escape into the vat surrounding the re-absorber, and 31 a pipe
leading therefrom, first into the cooler G, G, and then into the cooler G, from
which last the heated water is allowed to escape through the waste pipe 32.
33, a water escape pipe to discharge the heated water from the Liebig's
condenser B into the waste pipe 32.
84, a stop-cock connected by a suitable pipe to the upper part of the re-
absorber H, and to which is attached a flexible pipe whose end is plunged into
a vessel of fresh water.
35, a fresh water vessel for collecting the ammoniacal gas which ac-
companies the air expelled from the several vessels previous to starting the
work of the apparatus.
Having described all the various parts generally and in detail, it now

page_text: remains to explain the practical operation thereof, which is commenced by
forcing into the separator, the re-absorber, and the feeder through the two-
way cock 13° the liquid ammonia of commerce, which for use in the apparatus
is rectified to the required strength as follows:-Having closed all the cocks,
and the separator A having been filled to two-thirds of its capacity with the
aqueous solution of ammonia, and the re-absorber having been supplied with
the same strength of the ammoniacal solution to two-thirds of its capacity,
and, lastly, the feeder having been similarly supplied to one-third of its
capacity the steam admission cock 2 is opened, and heat is gently applied
through the internal coil 8 to the solution in the separator A, the condensed
steam cock 4 being also opened to let the condensed steam return to the
steam boiler. To establish communication between all the spaces of the
apparatus not filled with liquid the three pressure cocks 24, 240, 240, the
passing cock 17, the stop-cock 6, and the rectifying cock 8 are opened, then
the air-cock 34 is opened. By the admission of steam through the internal
coil 3 in the separator heat is transmitted to the ammoniacal solution, which
immediately begins to give off gas, which filling the empty spaces of the
vessels and pipes of the apparatus drives before it all the air contained therein.
The water in the vessel 35 absorbs the ammonia which escapes intermixed
with the expelled air, and the air passes away in bubbles. When the air
bubbles cease and a rattling noise is heard in the water it is known that all
the air has been expelled. All the cocks except the rectifying cock 8 and the
steam cocks are now shut. The rectifying cock is left open to allow the
ammoniacal gas contained in the separator A to be re-absorbed under pressure
by the liquid in the feeder F, which it absorbs by passing through the Liebig's
condenser B, the desiccator C, the branch pipe 7, and finally by the perforated
cross pipe 9, which distributes it amongst the solution in the feeder, thereby
greatly strengthening it ready for liquefaction; the pipe 15 returns during
the operation the aqueous vapor condensed in the desiccator C to the
separator A. The heat in the separator is gradually increased until the gas
therein is nearly all exhausted. The rectifying cock is now closed. Then are
opened the weak liquor stop-cocks 13 and 13°, (which last is the two-way
cock, and must be so turned that the communication with the re-absorber is
shut off, and the weak liquor can be removed,) and the weak liquor is driven
in succession through the coils in the coolers G and G, G. This weak liquor
being cooled is removed from the apparatus by the two-way stop-cock 18°, and
the stop-cocks 18 and 18° are thereupon closed. The extraction of the weak
liquor at this stage is to give an increased quantity of absolute ammonia into
the machine, in order to fill under the liquefying pressure all the empty

page_text: spaces. This operation should be repeated according to the number of vessels
to be refrigerated for the preservation of food. Being now ready for the
liquefying operation the steam cock 2 is shut, and the feed cock 11 and the
rectifying cock 8 are opened. The strengthened liquor in the feeder F being
placed under two equal pressures is allowed to run into the separator A by
its own gravitation until the quantity of liquid necessary for liquefaction is
passed; this being done the cocks 11 and 8 are closed. Steam is again
gradually admitted by the steam cock 2 to pass as before through the coil 3
by the condensed cock 4 to the steam boiler. The communication cock 6 being
opened a free current of gas takes place through the Leibig's condenser B,
the desiccator C, and the liquefying coil D into the liquefied gas receiver E,
the steam is gradually increased until the liquefying pressure is attained,
which pressure is maintained until nearly the whole of the ammonia in the
separator A is liquefied, which fact is known by looking at the level gauge I.
Ammoniacal gas being a non-permanent gas has the property, as discovered
by Faraday, of liquefying at a pressure of six and a half atmospheres when
exposed to a temperature of sixty degrees Fahrenheit, or at a lower or higher
pressure according to the temperature.
To obtain absolute ammoniacal gas it would be necessary to desiccate it
thoroughly by chemical agencies, but for the working of my apparatus such
perfect desiccation is not needed, as provision is made to return the aqueous
solution which escapes through the desiccator, which only dries the gas
according to the temperature of the water flowing through the bath. The
desiccated ammoniacal gas being compressed into the liquefying coil D at
the liquefying pressure soon changes its state to a liquid, giving off during
the chauge the latent heat it contains, which latent heat is removed by the
stream of cold water constantly flowing into and from the bath in which the
liquefying coil D and the gas receiver E are immersed. The liquefying
cock 6 and the steam admission cock 2 being closed pressure cock 24
next to the re-absorber is opened to allow the gas from the liquefying coil D
to press upon the saturated liquid in the re-absorber H, at the same time the
discharge cock 19 is opened, and the liquid flows through the internal pipe 18,
passing through pipe 10, and entering the feeder I', which vessel is not
allowed to be completely filled, one-tenth of its capacity being left vacant to
provide for the increased volume which it will have to hold when rectification
takes place after each successive liquefaction. The pressure cock 24 is now
closed, and the rectifying cock 8 is opened, and the remainder of the
ammoniacal gas contained in the weak liquor in the separator A is then
rectified into the feeder F, which operation effects the twofold object of

page_text: depriving the weak liquor of its ammonia and of strengthening the strong
solution in the feeder previous to its being liquefied. The rectifying cock 8
being again closed, and the weak liquor cocks 13, 13°, opened, and the two-
way cock 18° being turned, so as to convey the weak liquor into the re-
absorber H through the perforated ring 14, a little steam is admitted through
the coil 3, which soon generates sufficient pressure to overcome the resistance
offered by the gas in the re-absorber H. As soon as the weak liquor enters
the re-absorber the pressure is neutralised and the steam is turned off. The
weak liquor during its passage through the coolers G and G, G, has its
temperature lowered from three hundred degrees Fahrenheit to that of the
water flowing through the said coolers. The separator being now empty
another charge from the feeder is allowed to pass into it by the means already
described. All the open cocks are now shut, and the passing cock 14 is
opened, and the liquefied gas held in the gas receiver F flows by its combined
pressure and gravity into the gas compartment of the meat receiver I. When
the
gas receiver E is empty the passing cock 17 is closed, the steam admission
cock 2 and all other cocks requisite in the operation of liquefaction, as before
fully explained are opened, and the liquefaction is resumed.
Everything is now ready for the production of cold, which is effected as
follows: The freezing cock 22 connected with the gas compartment of the
meat-preserving vessel by U, pipe 21 and 21° is opened, and the gas in the
said compartment is allowed to enter the U-pipe 21, 21°, and to escape into
the weak liquor in the re-absorber by the perforated pipe 23. Into the
re-absorber the liquefied gas from the gas compartment of the meat receiver
rushes with great violence, for it is still under its liquefying pressure, and
there is a partial vacuum in the re-absorber, and further more ammoniacal
gas has so great an affinity for water that at a temperature of sixty degrees
Fahrenheit water will absorb about six hundred and sixty times its volume of
ammoniacal gas.
Under such circumstances the gas is re-absorbed, and the
liquor gradually restored to its full strength prepared for reliquefaction by the
process already described. During this operation the liquefied gas in the gas
compartment of the meat receiver losing its pressure immediately passes into
the gaseous state, and robs the vessel in which it was confined and its contents
of their heat. The cold soon becomes intense, and very low temperatures
can be obtained. After each liquefaction the gas compartment is replenished,
and the article of food in the meat receiver is reduced to the degree of
temperature desired, and such temperature can be maintained by regulating
the freezing cock, and thus enabling the apparatus by its self-action to
produce cold for days and weeks without any further liquefaction after

page_text: repeated gasifications in the gas compartment of the meat receiver, a cold
solution being the produce of the imperfect desiccation through the desiccator C,
accumulates, of which it is necessary to purge the gas compartment, which
object is accomplished by shutting the freezing cock 22 and opening the
pressure cock 24° next to the passing cock, and the purge cock 2400 leading
into the re-absorber H. This right time for the operation is when the re-
absorber is in vacuum after liquefaction is completed.
To avoid complication in the description of the apparatus I have represented
in a separate Drawing, called Figure Number 2, the mode by which heat is
applied to the separator. The heat is applied by steam which passes through
a pipe superheated by the waste heat of the smoke box, the flue, the funnel,
or chimney of the steam boiler, to be condensed and returned to the water
space of the said steam boiler. By this arrangement three important objects
are attained. First, the superheating of the steam by heat which would
otherwise be lost; second, the return of the excess of heat left in the con-
densed steam after it has effected the separation of the ammoniacal gas from
the liquid in the separator; and, third, the maintenance of a constant supply
of water in the steam boiler, thereby rendering impossible any risk of
explosion. A, the separator; Z, the boiler; 2, the steam cock for admitting
steam to the internal coil, already described amongst the component parts of
the Drawing (Figure No. 1); 36, the steam superheating pipe leading
from the steam room of the steam boiler through the smoke box, the flue, the
funnel or chimney of the said boiler, according to the contruction thereof.
This pipe may be varied in form according to the place in which it may be
fitted, but the object is the same to make use of the waste heat, and thereby
save fuel; 4, the return condensed water cock; 37, the pipe conveying the
condensed steam to the water space of the steam boiler.
Figure Number 3 represents what I call the "portable meat preserver."
This vessel, which is specially for use on short journeys or voyages, may,
however, be substituted for the meat receiver I of Figure Number 1. The
"portable meat preserver" is a double cased metallic vessel of suitable shape
placed inside a case or cask, and protected by some good non-conducting
substance, such as charcoal or gutta percha packed between the wood and the
metal. The object of this vessel is to preserve articles of food in portable
parcels, which is effected by forcing by suitable contrivances through the
narrow compartment between the two metal walls a freezing liquid, such as a
saturated solution of chloride of sodium or of chloride of calcium, which does
not congeal except at a very low temperature. The freezing medium is
introduced by a pipe at the lower or other part of the vessel as indicated by

page_text: the direction of the arrow, and after having circulated through the liquid
compartment of the "portable meat preserver" it is allowed to escape by
another pipe, as also indicated by an arrow, carrying off with it the heat con-
tained in the substance to be preserved by refrigeration. The heated liquid
returns to that part of the apparatus from which it derived its low temperature
to be again refrigerated for further use. The compartment through which
the freezing medium is made to circulate may be separated into two spiral-
shaped divisions, one of which should be filled with fresh water to be frozen,
at the same time the food to be preserved is operated on through the other
division by the freezing medium. The object is to surround the inner metallic
portion of the portable meat preserver with a band of ice, to assist in
maintaining at a low temperature the contents within. a, a, thin metallic
vessel containing the food to be refrigerated; 6 and 6, the liquid compartment
for the circulation of the refrigerating medium; c, a moveable pipe connection
screwed into the lower or other part of the liquid compartment, through which
the refrigerating medium is forced; co, also a moveable pipe through which the
refrigerating medium escapes; d, a screwed plug made of some non-conducting
material to fill the space left vacant on the removal of the moveable pipe; e, a
piece of wood with a countersunk screw to fill up the space cut in the wooden
covering, and to offer a flush surface after the pipe c is removed. Similar
arrangements are made for filling the spaces in the upper part of the metallic
vessel and its wooden covering; f, f, f, and f, the non-conducting substance
surrounding the metallic vessel; g and g, a wooden case or cask enclosing the
metallic vessel; h, a cover of wood and metal with some non-conducting
substance between, and lined on the inner side with india-rubber to prevent
the admission of air to the frozen food. This cover can be fixed to the case
or cask by wooden screws or other suitable means. When the liquid com-
partment is divided into two spiral-shaped portions, i, i, represent the freezing
medium space, and k, k, the ice space.
Having now described the nature and object of the said Invention, and the
manuer of performing the same, I would remark in conclusion, that I claim
as the Invention,―
The method of and apparatus for preserving fish, flesh, and fowl, and all
other articles of food by a process of refrigeration, substantially as herein
described.
I also claim the arrangements to obtain a continuous operation of the
apparatus without the use of any external force beyond the occasional
application of heat from a steam boiler.
I also claim the arrangements for applying heat to the separator

page_text: I also claim the arrangements for rectifying the gases after liquefaction.
I also claim the arrangements for removing the weak liquor from the
separator "into the "re-absorber" by its own pressure.
I also claim the arrangements for sending up into the feeder the strong
liquor from the "re-absorber."
I also claim the arrangements for returning the strong liquor into the
separator."
I also claim the arrangement of the "meat receiver."
I also claim the arrangement of the "portable meat preserver."
In witness whereof, I, the said William Mort, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-eight.