Improvements in Thawing Frozen Meat and in Apparatus therefor..
Year: 1888

page_text: Date of Application, 17th Nov., 1888
Complete Specification Left, 19th Aug., 1889-Accepted, 21st Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Thawing Frozen Meat and in Apparatus therefor..
We, GEORGE FRANCIS WATSON and PIERRE FRANÇOIS RENÉ LAFABREGUE, both
of 23, Boulevard de Strasbourg, Paris, in the Republic of France, Merchants, do
hereby declare the nature of this invention to be as follows:-
This invention relates to the thawing of meat which has been frozen for the purpose
of its preservation and to apparatus therefor.
The means which at present exist for preserving meat by means of cold are not
entirely satisfactory in consequence of the meat when thawed by the processes at
present in use rapidly assuming a dull and discolored appearance destroying the fresh
appearance so necessary to ensure a ready sale.
The object of our invention to remedy this defect and for this purpose we employ
hot dry air for thawing meat. The quarters of meat as they arrive in a frozen state
from the places where the animals are cut up are hung up in a close chamber in
which we deliver the thoroughly dry air, heated to a temperature of 40 to 50 degrees,
in a continuous or intermittent current. The air circulating around the meat quickly
thaws it, the heat causing the frozen parts to melt and the dryness of the air
removing the moisture resulting from the liquefaction.
The two essential conditions necessary to effect the thawing of the meat in a
successful manner are thus afforded.
by
A suitable apparatus for carrying out our invention comprises a chamber,,
preference of circular form, in which the meat is hung upon hooks fixed on
circular rails.
The chamber is by preference made of wood lined with zinc and is provided with
a jacket also of wood lined with zinc. Inside the chamber is a blower serving to
continuously circulate the dry, hot air entering through suitable tubes.
The air serving for thawing the meat passes through a drying apparatus
advantageously composed of small trays on which is placed the drying material such
as chloride of calcium, pumice stone saturated with sulphuric acid or other drying
medium. On leaving this drying apparatus the air passes through a tube into a coil
placed above a fire whereby it is heated. Thence it passes through a series of tubes
which distribute it in the chamber whence it escapes at the upper part through holes
communicating with the jacket. The hot air passes into the jacket and is delivered
through suitable pipes into a shaft serving to draw in the air which has been saturated
with moisture after its passage through the thawing chamber. The escape of the air
used for thawing the meat can be produced by means of any suitable arrangement of
heating apparatus. The chamber is provided with one or more doors to allow of
introducing the meat and it can besides be provided with windows through which the
degree of thawing of the meat in the apparatus can be ascertained.
The drying apparatus may be dispensed with if the air is furnished by a refrigerating
machine in which it is deprived by the cold of its natural moisture. The important
point is that the air should be charged with very little moisture, that is to say,
sufficiently dry to absorb the moisture which is disengaged from the meat being
thawed.
1000

page_text: COMPLETE SPECIFICATION.
Improvements in Thawing Frozen Meat and in Apparatus therefor
We, GEORGE FRANCIS WATSON and PIERRE FRANÇOIS RENÉ LAFABREGUE, both
of 23 Boulevard de Strasbourg, Paris, in the Republic of France, Merchants, do
hereby declare the nature of this invention 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 the thawing of meat which has been frozen for the purpose
of its preservation and to apparatus therefor.
The means which at present exist for preserving meat by means of cold are not
entirely satisfactory in consequence of the meat when thawed by the processes at
present in use rapidly assuming a dull and discolored appearance destroying the fresh
appearance so necessary to ensure a ready sale.
The object of our invention is to remedy this defect and for this purpose we employ
hot dry air for thawing meat. The quarters of meat as they arrive in a frozen state
from the places where the animals are cut up are hung up in a close chamber in which
we deliver the thoroughly dry air, heated to a temperature of 40 to 50 degrees
Centigrade in a continuous or intermittent current. The air circulating around the
meat quickly thaws it, the heat causing the frozen parts to melt and the dryness of
the air removing the moisture resulting from the liquefaction.
The two essential conditions necessary to effect the thawing of the meat in a
successful manner are thus afforded.
We avoid raising the temperature to a point which would effect the melting of
the most easily melted fats of the carcase, at the same time keeping the carcase in
air dry enough to avoid condensation of moisture so that it will give up to the
external air the moisture from the epidermis during the special drying stage. It will
thus be seen that the treatment by our apparatus differs from that carried on in the
drying apparatuses or stoves hitherto in use in that we confine ourselves to removing
from the epidermis of the carcase the moisture which it has condensed during the
freezing operation without depriving it of any of its natural juices.
A suitable apparatus for carrying out our invention is illustrated in the accompanying
drawing in which
Figure 1 is a longitudinal view half in elevation and half in section of such an
apparatus.
Figures 2 and 3 are transverse sections on the lines A B and C D respectively of
Figure 4 which is a view half in plan and half in horizontal section of the
apparatus.
It comprises two chambers of iron and rough glass or of other suitable material
which is absolutely impermeable, this being an indispensable condition to avoid
fermentation.
We suspend vertically the carcases or other bodies of animal origin to be thawed
and dried in these chambers, leaving a space between them sufficient for the circulation
of the air which passes downwards from top to bottom as hereinafter described.
Each chamber serves successively and alternately as a thawing chamber and a
drying and heating chamber.
We utilize for the thawing operation the heat brought by the hot air issuing from
the heating chamber. To this end the air, freed from dust by a suitable screen, is
brought to the required temperature by means of a vapour stove C and forced by the
blower D and the branched pipe E into the top of the heating and drying chamber F.
This movement of the air is controlled by operating a valve a.
The cold air in contact with the meat descends in horizontal layers to the floor of
the chamber which is also air-tight, passes under the partitions band is forced into the
flue G whence it enters the second forcing pipe H. By means of the valve c it is
forced into the thawing chamber I which it traverses from top to bottom and passes
under the partitions into the flue K which conducts it to the base of the pipe H
whence it escapes through the valve d.

page_text: The operation being ended, the meat is removed from the chamber F through the
door M, and is replaced by other meat to be thawed. By means of the lever f
actuating the valves a, c, d the general direction of motion of the air is changed so
that the chamber I becomes the heating chamber and so on.
The floor of each chamber is slightly inclined so as to allow the walls to be properly
washed; the water is discharged through the syphons S forming traps into the drain T
without there being any communication between the atmosphere, the chambers, and
the drain.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is :-
1. The herein described process of thawing meat which has been frozen in order
to preserve it, by the employment of dry heated air so as to melt the frozen parts and
remove from the epidermis the moisture which it has condensed during the freezing
operation.
2. The herein described apparatus for heating and drying the air and effecting the
operations of thawing and drying frozen meat.
3. The employment of glass and other substances in the form of thin impermeable
sheets for constructing the said apparatus.
4. The arrangement of flues and chimneys with valves allowing of alternately
causing the air to circulate in the two chambers substantially as hereinbefore
described.
Dated tha
KULLARY OLATUTING LAAM
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.