Method of and Apparatus for Raising the Temperature of Organic Substances and Alimentary Products generally, and particularly for Thawing Frozen Meat.
Year: 1895

page_text: Date of Application, 16th Mar., 1895
Complete Specification Left, 23rd Nov., 1895-Accepted, 28th Dec., 1895
PROVISIONAL SPECIFICATION.
Method of and Apparatus for Raising the Temperature of Organic
Substances and Alimentary Products generally, and particularly
for Thawing Frozen Meat.
I, ALEXANDER MELVILLE CLARK, of the Firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Chartered
Institute of Patent Agents, do hereby declare the nature of this invention
(a communication to me by La Compañia Sansinena de Carnes Congeladas, of
523, Calle Piedad, Buenos Ayres, South America,) to be as follows:-
This invention relates to a method of warming organic substances and alimentary
products in general, and particularly of effecting the thawing of meat which has
been preserved by freezing.
In the practical application of methods of preservation by freezing it has been
found that although by the action of cold the inherent qualities and natural
external appearance of the goods (upon which their commercial value depends)
were retained, yet these advantages were frequently lost when the thawing or
In close,
raising of the temperature of the goods took place in the open air.
moist, and stormy weather the raising to the normal temperature of the goods
brought from the cold storage chamber or a cooled cellar, may be attended by
notable changes in the external aspect and even by rapid decomposition consequent
on the sudden change of temperature.
Many plans have been tried with a view to avoid this result, more particularly
in respect of frozen meat. Thus it has been attempted to effect the thawing by a
current of dry and heated air blown in large volume over the goods by means of
fans or established by mere difference of density, and this method has been
supplemented by the artificial desiccation of the air by means of calcium chloride
or by the action of a refrigerator for condensing the moisture in the form of snow
or hoar frost followed by reheating of the air.
The present invention relates to a method whereby still better results may be
obtained.
According to present practice, the thawing in the open air is artificially stimulated
by external warming by contact or by radiation, or with the aid of fans, supplying
hot dry or moist air; but the de-frosting or raising of the temperature cannot be
effected rapidly in consequence of the absolute necessity of avoiding fermentation,
which would entail the deterioration of the goods, or so far modify their aspect as
to reduce their commercial value.
Experience shews that the methods heretofore adopted have not sufficiently
allowed for the slow penetration of heat, consequent on the fact that alimentary
products of all kinds and organic matters in general preserved by cold are very bad
conductors of heat and are nearly impenetrable by the ambient air under ordinary
circumstances, even when set in motion by a fan; hence the heating through to
the centre of goods of certain bulk occupies so long a time that the exterior
portions are liable to putrefy, dry up, or alter in appearance, while the internal
portions are still frozen.
The method of accelerating the defrosting or thawing which constitutes this
invention is based upon the following experiment. If a quarter of meat, however
large and whether fresh or frozen as hard as stone, be placed in a closed receptacle

page_text: in which is created an artificial pressure of air or gas compressed to severa
atmospheres, all its cells will become penetrated, to its core and the bony portion
although surrounded by a considerable thickness of muscular tissue, is very quickly
impregnated to the marrow by the compressed air. Hence it has been concluded
that the true mode of rapidly establishing an exchange of caloric within masses of
meat or other organic matters which are so refractory to the penetration of heat
by radiation or natural conductibility, is to subject the goods to alternations of
pressure in order to cause the penetration throughout their mass of the air or gas
which is the vehicle of the heat necessary for warming or thawing the substance
whose temperature it is desired to raise to that of the outer atmosphere on removal
from the cold storage or refrigerating chambers.
The method, therefore, consists, briefly, in setting up the circulation of air
throughout the mass under treatment, by varying the external atmospheric
pressure in which it is placed. The atmosphere may be air or any gas whatsover.
The method may be applied, in practice, in two different ways:-
1st. By transferring the goods to be thawed or warmed alternately from one to
the other of different chambers containing atmospheres at different pressures and
temperatures ;
2nd. By varying the pressure and temperature of the atmosphere of the same
chamber in which the goods remain untouched.
In either case, any suitable means may be employed for externally heating the
goods whether by radiation or by heating before, or during, the operation, the
gases constituting the atmosphere under variable pressure in which the goods are
placed. For example, if atmospheric air be employed, it, or the gases which may
take its place, may be supplied under pressure to the warming chamber or
chambers, or be compressed directly therein, and may be previously desiccated
or not, or be subjected in the chamber to any suitable process of desiccation.
Any suitable method of heating the air or gas or the matters under treatment
may be adopted, particularly of heating the air before it enters the chamber, or by
employing radiating surfaces within or upon the walls of the chamber, such as
pipes, gilled tubes, jackets, or the like, for the circulation of hot water or
steam, etc. The air or gas introduced into the chamber may be dry or moist and
may be charged or not with vapours or gases having antiseptic or other desirable
qualities.
The pressure may be produced by any convenient means and the periods of
compression and dilatation or rarefaction may be varied, according to the nature
and bulk of the goods under treatment, it being preferred to place the goods in a
closed chamber which is alternately exhausted and supplied with an atmosphere at
normal pressure or at a higher pressure by any suitable means; similar means may
be employed for establishing the internal circulation and the calorific exchange
which is the object sought to be attained.
It is to be observed that the scientific experiments of Pasteur have demonstrated
that the effect of subjecting meat to compressed air is to kill the microbes or
ferments, which cause mouldiness or putrefaction, and the action of the compressed
air in this process of thawing has, therefore, the incidental effect of conducing to
the further preservation of the meat treated according to this improved process.
On the other hand the rarefaction or exhaustion of the atmosphere affords the
means of effecting a partial desiccation of the substance under treatment and of
preventing, especially in the case of meat, the escape of the juices or serous liquid
which is usually noticeable after natural thawing.
The process may be carried out in practice by means of any apparatus suitable
for effecting the warming or thawing operation whilst permitting of the variation
of the pressure of the atmosphere in which the substances under treatment are
placed, and I have illustrated, in the accompanying drawing, forming part of this
Specification, an example of apparatus which has been designed for the purpose.
Figure 1 is a transverse vertical section, and Figure 2 a plan view of the apparatus,
the same letters of reference denoting like parts in both figures.

page_text: The apparatus consists of a closed chamber a in which are placed the
substances 6 to be treated, said chamber being provided with end covers c which
are held closed by any suitable means. Within the chamber is fixed a suspension
rail d from which the substances are hung by hooks attached to roller carriages
running on the rail. To the chamber a are connected pipes e for the introduction
and withdrawal of the air or gas under pressure, said pipes being controlled by
stop valves and connected with vacuum pumps or with compressors. A series of
steam or hot water circulation pipes f, placed within the chamber, enable the
internal temperature of the chamber to be raised to the desired point, the pressure
and temperature being indicated by a gauge and thermometer placed at g. The
chamber a is, for the most part, enclosed in a tank or jacket h, in which steam or
liquid, at a suitable temperature, is caused to circulate between the inlet and outlet
pipes i.
The form and arrangement of the apparatus may, however, be varied to suit the
different substances to be treated.
Dated this 16th day of March 1895.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
Method of and Apparatus for Raising the Temperature of Organio
Substances and Alimentary Products generally, and particularly
for Thawing Frozen Meat.
I, ALEXANDER MELVILLE CLARK, of the Firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Chartered Institute
of Patent Agents, do hereby declare the nature of this invention (a communication
to me by La Compañia Sansinena de Carnes Congeladas of 523, Calle Piedad,
Buenos Ayres, South America,) and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
This invention relates to a method of warming organic substances and alimentary
products in general, and particularly of effecting the thawing of meat which has
been preserved by freezing.
In the practical application of methods of preservation by freezing it has been
found that although by the action of cold the inherent qualities and natural
external appearance of the goods (upon which their commercial value depends)
were retained, yet these advantages were frequently lost when the thawing or
raising of the temperature of the goods took place in the open air. In close, moist,
and stormy weather the raising to the normal temperature of the goods brought
from the cold storage chamber or a cooled cellar, may be attended by notable
changes in the external aspect and even by rapid decomposition consequent on the
sudden change of temperature.
Many plans have been tried with a view to avoid this result, more particularly
in respect of frozen meat. Thus it has been attempted to effect the thawing by a
current of dry and heated air blown in large volume over the goods by means of
faus or established by mere difference of density, and this method has been supple-
mented by the artificial desiccation of the air by means of calcium chloride or by
the action of a refrigerator for condensing the moisture in the form of snow or
hoar frost followed by reheating of the air.
The present invention relates to a method whereby still better results may be
obtained.
According to present practice, the thawing in the open air is artificially
stimulated by external warming by contact or radiation, or with the aid of fans

page_text: supplying hot dry or moist air; but the de-frosting or raising of the temperature
cannot be effected rapidly in consequence of the absolute necessity of avoiding
fermentation, which would entail the deterioration of the goods, or so far modify
their aspect as to reduce their commercial value.
Experience shews that the methods heretofore adopted have not sufficiently
allowed for the slow penetration of heat, consequent on the fact that alimentary
products of all kinds and organic matters in general preserved by cold are very
bad conductors of heat and are nearly impenetrable by the ambient air under
ordinary circumstances, even when set in motion by a fan; hence the heating
through to the centre of goods of certain bulk occupies so long a time that the
exterior portions, are liable to putrefy, dry up, or alter in appearance, while the
internal portions are still frozen.
The method of accelerating the de-frosting or thawing which constitutes this
invention is based upon the following experiment. If a quarter of meat, however
large and whether fresh or frozen as hard as stone, be placed in a closed receptacle
in which is created an artificial pressure of air or gas compressed to several
atmospheres, all its cells will become penetrated to its core and the bony portion,
although surrounded by a considerable thickness of muscular tissue, is very quickly
penetrated to the marrow by the compressed air. Hence it has been concluded
that the true mode of rapidly establishing an exchange of caloric within masses of
meat or other organic matters which are so refractory to the penetration of heat
by radiation or natural conductibility, is to subject the goods to alternations of
pressure in order to cause the penetration throughout their mass of the air or gas
which is the vehicle of the heat necessary for warming or thawing the substance
whose temperature it is desired to raise to that of the outer atmosphere ou removal
from the cold storage or refrigerating chambers.
The method, therefore, consists, briefly, in setting up the circulation of air
throughout the mass under treatment, by varying the external atmospheric pressure
in which it is placed. The atmosphere may be air or any gas whatsoever.
The method may be applied, in practice, in two different ways:-
1st. By transferring the goods to be thawed or warmed alternately from one to
the other of different chambers containing atmospheres at different pressures and
temperatures ;
2nd. By varying the pressure and temperature of the atmosphere of the same
chamber in which the goods remain untouched.
In either case any suitable means may be employed for externally heating the
goods, whether by radiation or by heating before, or during, the operation, the
gases constituting the atmosphere under variable pressure in which the goods are
placed. For example, if atmospheric air be employed it, or the gases which may
take its place, may be supplied under pressure to the warming chamber or
chambers, or be compressed directly therein, and may be previously desiccated
or not, or be subjected in the chamber to any suitable process of desiccation.
Any suitable method of heating the air or gas or the matters under treatment
may be adopted, particularly of heating the air before it enters the chamber, or
by employing radiating surfaces within or upon the walls of the chamber, such as
pipes, gilled tubes, jackets, or the like, for the circulation of hot water or
steam, etc. The air or gas introduced into the chamber may be dry or moist and
may be charged or not with vapours or gases having antiseptic or other desirable
qualities.
The pressure may be produced by any convenient means and the periods of
compression and dilatation or rarefaction may be varied, according to the nature
and bulk of the goods under treatment, it being preferred to place the goods
in a closed chamber which is alternately exhausted and supplied with an
atmosphere at normal pressure, or at a higher pressure, by any suitable means;
similar means may be employed for establishing the internal circulation and the
calorific exchange which is the object sought to be attained.
It is to be observed that the scientific experiments of Pasteur have demonstrated

page_text: that the effect of subjecting meat to compressed air is to kill the microbes or
ferments which cause mouldiness or putrefaction, and the action of the compressed
air in this process of thawing has, therefore, the incidental effect of conducing to
the further preservation of the meat treated according to this improved process.
On the other hand the rarefaction or exhaustion of the atmosphere affords the
means of effecting a partial desiccation of the substance under treatment and of
preventing, especially in the case of meat, the escape of the juices or serous liquid
which is usually noticeable after natural thawing.
The process may be carried out in practice by means of any apparatus suitable
for effecting the warming or thawing operation whilst permitting of the variation
of the pressure of the atmosphere in which the substances under treatment are
placed, and I have illustrated, in the drawing accompanying the Provisional
Specification, an example of apparatus which has been designed for the
purpose.
Figure 1 is a transverse vertical section, and Figure 2 a plan view of the
apparatus, the same letters of reference denoting like parts in both figures.
The apparatus consists of a closed chamber a in which are placed the
substances b to be treated, said chamber being provided with end covers c which
are held closed by any suitable means. Within the chamber is fixed a suspension
rail d from which the substances are hung by hooks attached to roller carriages
running on the rail. To the chamber a are connected pipes e for the introduction
and withdrawal of the air or gas under pressure, said pipes being controlled by
stop valves and connected with vacuum pumps or with compressors.
A series of
steam or hot water circulation pipes f placed within the chamber, enable the
internal temperature of the chamber to be raised to the desired point, the pressure
and temperature being indicated by a gauge and thermometer placed at g. The
chamber a is, for the most part, enclosed in a tank or jacket h in which steam or
liquid, at a suitable temperature, is caused to circulate between the inlet and outlet
pipes, i.
The form and arrangement of the apparatus may, however, be varied to suit the
different substances to be treated.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1st. The process of effecting the de-frosting or thawing of organic substances
and alimentary products which have been preserved by freezing, which consists in
establishing an internal circulation or penetration of the heat within the mass to
be treated, by alternate compression and re-expansion or rarefaction of the
enveloping atmosphere brought to a suitable temperature by any appropriate
means.
2nd. The herein described apparatus for use in carrying out the process of
thawing hereinbefore claimed, substantially as set forth.
Dated this 23rd day of November 1895.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.