Improvements in the Method of Thawing Frozen Meat and the like, and in Apparatus employed therein.
Year: 1894

page_text: Date of Application, 23rd Jan., 1894
Complete Specification Left, 2nd Mar., 1894-Accepted, 7th Apr.. 1894
PROVISIONAL SPECIFICATION.
Improvements in the Method of Thawing Frozen Meat and the like,
and in Apparatus employed therein.
We CHRISTIAN ADOLPH LICHTENBERG of The National Liberal Club
Whitehall Place, London, Gentleman, and THOMAS LOWNDES WASHINGTON
of 14 Arno Road, Birkenhead, Liverpool, Engineer, do hereby declare the nature
of this invention to be as follows:-
This invention relates to an improved process of thawing frozen meat and other
animal food and to apparatus employed in carrying out the process in practice.
The object of the invention is to avoid the injury to the appearance and quality
of the meat caused by the superficial condensation of moisture thereon and by the
loss of the animal juices by the so called bleeding of the meat which takes place
when the meat is thawed in the ordinary manner.
This we are enabled to accomplish by subjecting the meat to a continuous
circulation of dry air at a carefully graduated and progressive temperature
whereby the condensation of moisture and other evils consequent on subjecting
the meat to a sudden change of temperature are entirely avoided.
In carrying the process into effect the air current to which the meat is exposed
is composed of a mixture in varying proportions of cold air at say 19° F. and of
air heated up to about 70° by steam pipes or other surface heaters, the supply
of the air from these two sources being controlled by a suitable arrangement of
valves whereby the relative proportions of the hot and the cold air may be
graduated to any required extent.
The combined current is forced or drawn through the thawing chamber by a
fan or by exhaustion by any suitable means and before entering the thawing
chamber it may be thoroughly dried by being brought into contact with a
hygrometric substance.
The temperature of the combined current at the beginning of the operation
should be about 26° F. and be gradually increased up to about 60° at the conclusion
of the operation for which the time required would be from two to five days.
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C. A. LICHTENBERG,
T. L. WASHINGTON,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in the Method of Thawing Frozen Meat and the like,
and in Apparatus employed therein.
We CHRISTIAN ADOLPH LICHTENBERG, of The National Liberal Club,
Whitehall Place, London, Gentleman, and THOMAS LOWNDES WASHINGTON,
of 14, Arno Road, Birkenhead, Liverpool, Engineer, 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 an improved process of thawing frozen meat and other

page_text: animal food, and to apparatus employed in carrying out the process in practice on
a large scale, so as to enable the importer of, or other large dealer in, the frozen
meat to supply the same in a completely thawed condition to the retailer.
The object of the invention is to avoid the injury to the appearance and quality
of the meat, caused by the superficial condensation of moisture thereon, and by the
loss of the animal juices by the so-called bleeding of the meat which takes place
when the meat is thawed in the ordinary manner.
This we are enabled to accomplish by subjecting the meat to a continuous
circulation of dry air at a carefully graduated and progressive temperature,
whereby the condensation of moisture and other evils consequent on subjecting the
meat to a sudden change of temperature are entirely avoided.
In carrying the process into effect, the air current to which the meat is exposed
is composed of a mixture in varying proportions of cold air at, say, 19 degrees F.,
and of air heated up to about 70 degrees by steam pipes or other surface heaters,
the supply of the air from these two sources being controlled by a suitable arrange-
ment of valves, whereby the relative proportions of the hot and the cold air may
be graduated to any required extent. The object of using a mixture of very cold
and of heated and dried air is not only to enable the temperature of the air
supplied to the thawing chamber to be brought under complete control and graduated
as required, but to ensure the dryness of the air necessary for the successful
conduct of the operation.
The combined current is forced or drawn through the thawing chamber by a
fan, or by exhaustion. The temperature of the combined current at the beginning
of the operation should be about 26 degrees F., and be gradually increased up to
about 60 degrees at the conclusion of the operation, for which the time required
would be from two to five days, the duration of the thawing operation depending
on whether carcases, sides, or joints of beef or of mutton are to be thawed.
Reference is to be had to the accompanying drawings forming part of this
Specification, wherein we have illustrated in sectional elevation the apparatus
employed in carrying out the process.
A is the store chamber, in which the frozen meat is hung and maintained at a
temperature of about 19 degrees F. to be stored until it is required. B is the
thawing chamber in which the frozen meat is hung during the operation of thawing
it, and C is an intermediate chamber in which the regulation of the supply of cold
air and of warmed and dried air to be mixed together and supplied to the thawing
chamber is effected.
In the chamber C is placed a steam heated coil D by, which the air drawn
from chamber C is warmed and dried before entering a trunk E through a regulating
slide F.
The cold air at say 19 degrees F. is drawn from chamber A through a passage
controlled by a regulating slide G, the two currents of air being mixed in due
proportion in the trunk E from which the mixed current passes through another
regulating slide H and through a filter I made of charcoal packed between
perforated diaphragms to a fan K situated within the continuation E' of the trunk
and driven preferably by an electromotor L. The trunk E' is continued through
into the thawing chamber B and may extend any distance into the same, its end
being either open or provided with one or more regulating slides for controlling
and distributing the supply of the mixed current of air forced into the chamber B
by the fan.
In this chamber the air is delivered near the floor, the air circulating
continuously around the chamber B, and escaping at an outlet in the roof (should
the air require changing) regulated by a flap M, operated by a cord or other
mechanical connections preferably from within the chamber C. This last mentioned
chamber is provided with a fresh air inlet, preferably in the roof and controlled by
a similarly operated flap N. O is a coil of pipes in the upper part of the thawing
chamber B, through which ammonia may be caused to circulate, to promote a cold
temperature independently of the cold air in chamber A, when it is not desirable
to draw any of the cold air supply from the cold storage chamber A..

page_text: It is to be understood that the cold air need not necessarily be drawn from
the cold storage chamber A but may circulate from this independent source, as
desired.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
The herein described method of thawing frozen meat, which consists in subjecting
the same to a continuous circulation of dry air formed of a mixture of very cold
air and of air dried and heated to about the temperature specified, the proportions
of the mixture being varied in the course of the operation, so as to gradually raise
the temperature of the mixture, substantially between the limits indicated, the
operation being performed substantially in the manner and by means of apparatus
such as herein specified.
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1004
C. A. LICHTENBERG,
T. L. WASHINGTON,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.