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Патент USA US2137902

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Nov. 422, 1938.
¢_ T_ WALTER
2,137,902
QUICK FREEZ ING PROCES S
Filed NOV. 2l, 1936
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ATTORNEY
Nov. 22, 1938.
Q_ T_ WALTER
.
2,137,902
QUICK FREEZING PROCESS
Filed NOV. 2l, 1936
2 Sheets-Sheet 2
ATTORNEY \
'Patented Nov. 22, 1938
2,137,902
UNITED STATES
PATENTl
2,137,902
@UNIE FREEZINGÍ PROCESS
Charles 'i'. Waiter, Chicago, lill., assigner to in»
dustrial Patents Corporation, Chicago, mi., a
corporation of Delaware
Application 'November El, i936, Ferial lilo. Multi’
it matroos.
This invention relates to a quick ‘freezing
process for foods and to apparatus for carrying
out the process.
One of the objects of the invention is to provide
5 an improved quick freezing process.
Another object of the invention is to provide
apparatus for carrying out an improved quick
freezing process.
Other objects will be apparent from the de
scription and claims which follow.
As is well known, quick freezing involves ad«
vantages over slow freezing in that in quick
freezing the ice crystals formed in the foods are
small and do not rupture the cell walls, avoiding
15 an excessive moisture loss by cellular leakage
upon defrosting.
The present invention is particularly adapted
for quick freezing poultry.
Embodiments of apparatus involved in the'
Valve i2 is employed for closing the retort ofi
from the compressor. Pump iii is provided to re»
turn to the receiver any liquid refrigerant re»
maining in retort i after completion of 'the
freezing operation prior to opening the retort for it
removal of the product. Liquid refrigerant in
the retort returns to receiver it through line 2t
provided with valve 2| and line il? provided with
valve 23. Gauge 24 is provided for visual ¿ob
servation of the level of liquid refrigerant in li)
retort i.
The apparatus shown in Figure l may be oper
ated in the following manner:
Assuming valves I2 and I8 are closed and that
receiver I6 is filled with liquid refrigerant under l5
suitable pressure and temperature conditions,
retort I is open at head 2, the desired quantity of
product is loaded into the retort and cover 2
tightly closed. Valve II is opened slightly to al
20 present invention are shown in the drawings.
low air retained in the retort to escape. Valve I8 20
is next opened and a suitable quantity of refrig
of one form of apparatus involved in the present I erant permitted to flow into retort I through pipe
I1. A sufiicient quantity of refrigerant is admit
invention.
ted to retort I to completely cover all product to
Figure 2 is a side view, partly in section, of an
25 other form of apparatus Vwhich may be employed be refrigerated, the level being observed in gauge 25
24. When it appears that substantially all air
in carrying out the process of the present inven
Figure 1 is a schematic view, partly in section,
tion.
'
' Referring now more particularly to Figure 1:
Retort I is provided with a removable head 2 at
30 one end. Head 2 may be held tightly in position
by any suitable means as bolts 3 and wing nuts 4,
and is removed to charge the retort with product
to be frozen. Product 5 is placed in retort I on
rack 6. It will be noted that retort I is provided
85 with vapor chamber 1 to avoid return of slugs of
liquid through pipe 8 to compressor 9.
The present invention is carried out with a
within the retort I has b'een discharged through
valve I I, this valve is closed. Pressure is now built
up in retort I. The pressure will depend upon the
nature of the refrigerant and the temperature of 80
the product and retort. Valve I8 is closed after a
suitable quantity of refrigerant has been admit
ted to the retort. Compressor 9 is then started
and valve I2 opened, starting the 'pumping down
process.
As soon as compressor 9 starts to re- 35
move gas from retort I, some of the liquid
refrigerant in retort I evaporates, reducing the
suitable liquid refrigerant, as for example liquid - temperature of the mass of liquid refrigerant
and the surrounding materials. As the vapor
pressure in retort I is lowered, the temperature 40
II. Pipe 8 is provided with valve I2 and returns of the refrigerant is lowered. With such refrig
erants as liquid carbon dioxide, very low tem
gaseous refrigerant to compressor 9 from cham
peratures may be obtained, and consequent rapid
ber 'l of retort I. Compressor 9 delivers the com
pressed refrigerant in gaseous form through line chilling of the product in trays 6.
'I'he shell of the retort is heavily insulated 45
I3 to condenser I4 which may be of any suitable
type and is designed to discharge the liquefied- against the transfer of atmospheric heat into the
refrigerant through pipe I5 into receiver I6. Re
system as by insulation 25. Similarly the receiver
ceiver I6 is preferably of large capacity and is heavily insulated as by insulation 26.
‘As the freezing of the product proceeds, if more
should contain enough of the liquefied refrig
refrigerant is desired to maintain complete sub- 50
erant to fill retort I to the desired level.
.
Liquid refrigerant is delivered from the receiv
mersion of the product, the desired quantity may
er I6 to retort I through pipe I1 provided with be admitted at will through valve I8.
After freezing has proceeded to the desired ex
valve I8 which functions as the control valve for
shutting off the receiver I6 from the retort l, tent, valves 2I and 23 may be opened and pump
I9 placed in operation to pump the remaining 55
~when the retort is to be opened.
carbon dioxide. Before the system is started, air
40 Ais removed through pipe I0 provided with valve
45
'
50
'
55
2
liquid refrigerant from retort I into receiver I6.
After all of the refrigerant in retort I has thus
been returned to receiver I6,` valves 2l and 28
may be closed. Compressor 9 should continue
to operate until the'pressure in retort i has been
reduced to atmospheric pressure or less.
Com
pressor 9 may then be stopped and the retort I
tinues to operate, the temperature of the liquid
refrigerant continues to lower, concurrently low
ering the pressure within space 28. The com.-`
pressed gas passed into the condenser I4 is lique
fled and returned to receiver I6. After'a period
of time, any desired temperature for the liquid
refrigerant may be obtained within the limits of
'opened with safety to permit removal of the
the physical characteristics of the refrigerant.
product.
about the product will be rapidly and completely
For example, if the liquid refrigerant is carbon
dioxide and it is desired to operate ata tempera 10
evaporated from the product during subsequent
pounds per square inch will be maintained in
handling.
receiver I6. After the desired temperature oi
the refrigerant has been reached, it will be main
tained while the compressor is operated at the 15
suction pressure corresponding to that tempera
ture.
Retort l is now filled with a quantity of the
product to be refrigerated, head 2 tightened in
place, and air pump 29 started for the purpose 20
of extracting air from chamber I and to avoid
the introduction of substantial quantities of un
liqueflable gases into the system. If desired, a
simple blow-off valve may be provided as a sub
stitute for air pump 29 permitting the valves to 25
,
Any liquid refrigerant which may remain inv or
.
In the refrigeration of foods, it is essential that
15 the refrigerant be one which is not absorbed and
must be one which is relatively inexpensive, non
toxic, convenient to handle, and which has physi
cal and thermal characteristics making possible
extremely low temperatures and rapid rates lofl
heat exchange. Liquid carbon dioxide is such a
refrigerant.
`
'
Referring now more particularly to Figure 2:
Retort I is provided with head 2 which may be
securely fastened to retort I by means of bolts
3 and wing nuts 4. Product 5 may be placed upon
racks 2l. It is understood, of course, that retort
i must be sufficiently strong to 'withstand the
ordinary working pressures to be imposed upon
it. Retort I is covered with insulation 25 and
receiver I5 is covered with insulation 26. Re
ceiver i6 functions as a liquid receiver and as
an evaporator and is connected to retort I by
pipe Il provided with valve i8. Chamber I 6 is
adapted to hold a quantity of liquid refrigerant
to any suitable level, the space 2t above the lique
fied refrigerant being occupied by the refrigerant
in its gaseous state.
A suitable compressor machine 9 is included
in the`systern to deliver the hot compressed gas
to the condenser ld through pipe i3 where it is
liqueñed and returned to receiver iii through
pipe iii. Airfpump 2@ is provided to exhaust
chamber i of air at the start of the freezing
cycle communicating with retort i through pipe
Sti' and pipe i0 provided with valve 3i. Pipe 3i!
is provided with valve 32. Air withdrawn by pump
29 is exhausted through pipe 33. The pump 34,
suitable for handling liquid refrigerant, is em
ture of 0° F., a. pressure of approximately 300
remain open after a small quantity of liquid car
bon dioxide is introduced into chamber I. The
evaporating carbon dioxide will tend to dispel the
air through the blow-off valve, but this method
would entail a loss of refrigerant and, conse 30
quently, the pump is preferred.
After the chamber i has been well exhausted
by the action of air pump 29, valves I8 and 32
are opened, permitting the prechilled liquid re
frigerant to enter the retort and completely or
partially flood the interior of retort i. Liquid 35
refrigerant comes in contact with the product
to be chilled at the minimum temperature of the
refrigerant, causing freezing of the product to
commence immediately. Contact of the liquid
refrigerant with the warm. product results in a 40
heat exchange and the evaporation of some of
the liquid refrigerant. The gases thus formed
are drawn oiî through pipe line 3S to the com
pressor 9, maintaining a minimum temperature
of the refrigerant at a constant value.
The system assures that the maximum pressure
in retort i is that pressure corresponding to the
ployed to return quantities of liquid refrigerant ~ minimum temperature of the refrigerant. ' The
from retort l to receiver lâ at the end of the carbon dioxide operating from 0° to 50° F. the
50 freezing
process. Pump 34 removes -refrigerant maximum pressure in the chamber will be about 50
from retort i through pipe 35 provided with valve 300 pounds. On the other hand, the pressure>
3d, and returns the refrigerant from receiver i5 which may exist in -receiver i6 will be much
through pipe 3l communicating with pipe i5. higher than this and will correspond to the vapor
Retort
i is provided with safety valve 38 to pre
pressure of the liquid refrigerant at the highest
55
vent damage to the apparatus in, the event of
excessive pressure.
Duringthe operation of the system, gas evap
orating from the liquid refrigerant in retort i
is Withdrawn through pipe 39 communicating
with pipe dil at d i. Gaseous refrigerant formed in
the receiver I5 may also be withdrawn through
pipe dil to compressor 9. Pipe il@ is provided with
valve d2 between compressor it and T di.
65
The operation ofthe apparatus will be readily
understood by reference to Figure 2. Assuming
that the receiver I '6 is nearly full of liquid refrig
erant such as liquid carbon dioxide, the liquid
being at room temperature, valves iß'and 32 are
70 closed. Valve d2 is opened` and the compressor
9 started. The vapor pressure in space 2S will
be reduced and some ef the liquid refrigerant
will be evaporated. This evaporation will bring
about a reduction in the temperature of the re
75 maining refrigerant. .As the compressor con
temperature that may prevail in the receiver,
which may be as high as 100° or more F.
After the system has operated sufficiently to
chill or freeze the product to the desired degree,
the freezing operation is stopped by closing valves
i8 and 32, and starting pump 34, drawing oil” 60
from the bottom of the retorti the liquid re
frigerant remaining therein and returning it
through pipe 3l to receiver I6. The refrigerant
is not heated before being returned to receiver i6, 65
but is returned at approximately its minimum
temperature. After all of the liquid has -been
withdrawn from retort I, pump 34 may be
stepped and valve 36 closed. Valve 42 may be
closed and valve 32 opened. With the compres
sor operating, retort I may be pumped down to
atmospheric pressure. It is now in condition for
opening and removal of the product.
The apparatus which has been described re
suits in extremely rapid freezing, permitting a 75
3
9,137,902
chicken to be frozen solid in about 15 minutes.
means including an air pump having means com
This rapid freezing is brought about by the ex~tremely low temperature involved and the inti
vmate contact between the freezing medium and
the product to be frozen. Due to the efficiency of
the apparatus, its capacity is high and the in
liquefied refrigerant, a freezing retort, a liquefied
refrigerant receiver connected with said retort by
vestment relatively low.
`
I claim:
1. In a freezing device, a product retort, a pipe
10 from said retort communicating with a compres
sor, a condenser connected with said compressor,
a liquefied refrigerant receiver connected' with
said condenser, a pipe communicating with said
receiver and said retort, and a pump for returning
15 liquefied refrigerant from said retort to _said re
ceiver as desired.
2. In a freezing device, a product retort, a
pipe from said retort communicating with a com
pressor, a condenser connected with said com
20 pressor, a liquefied refrigerant receiver con
nected with said condenser, a pipe communicat
ing with said receiver and said retort, a pump for
returning liquefied refrigerant from said retort
to said receiver as desired, and an air vent pro
25 vided with a valve for preventing excessive pres
sures within the retort.
3. In a freezing device, a product retort, a pipe
from said retort communicating .with a compres
sor, a condenser connected with said compres
30 sor, a liquefied refrigerant receiver connected
with said condenser, a pipe communicating with
said receiver and said retort, a pump for return
ing liquefied refrigerant from said retort to said
receiver as desired, an air vent provided with a
35 valve for preventing excessive pressures within
the retort, a valve positioned between said re
ceiver and said retort, a pipe connecting said
pump and said retort, a valve in said last men
tioned pipe, and a pipe connecting said pump and
40 said receiver.
4. In a freezing device, a product retort, a pipe
from said retort communicating with a compres
sor, a condenser connected with said compressor,
a liquefied refrigerant receiver connected with
45 said condenser, a pipe communicating with said
receiver and said retort, a pump for returning
liquefied refrigerant from said retort to said re
ceiver- as desired, an air vent provided with a valve
for preventing excessive pressures within the re
50 tort, a valve positioned between said receiver and
said retort, a pipe connecting said pump and said
retort, a' valve in said last mentioned pipe. a
pipe connecting said pump and said receiver, and
municating with said retort for exhausting air
from said retort.
5. In apparatus for quick freezing food in a
a pipe, a valve in said pipe, a pipe leading from
said receiver to a compressor, said last-mentioned
pipe provided with a valve, a pipe leading from
said retort to said compressor. said last men 10
tioned pipe'provided with a valve, a pipe lead
ing from said compressor to a condenser, a pipe
leading from said condenser to said receiver,apipe
leading from said retort to an exhausting air
pump, a pipe leading from said retort to a liquidl l5
pump, a valve in said pipe between said retort
and said liquid pump, and a pipe leading from
said liquid pump to said receiver.
6. In a quick freezing device, a closed retort
having openable means for admitting product
thereto, a liquefied refrigerant receiver commu
nicating >with the retort, means controlling the
ñow of liquefied refrigerant from the receiver to
the retort, a compressor condenser circuit con
necting the retort with the receiver, said com
presser condenser circuit being adapted for with
drawing gaseous refrigerant from the retort and
for delivering liquefied refrigerant to the receiv‘~
er, and means for delivering liquefied refrigerantI
30
from the retort to the receiver.
7. In a quick freezing device, a closed retort
having openable means for admitting product
thereto, a liquefied refrigerant receiver commu
nicating withthe retort,meanscontrolling the flow
of liquefied refrigerant from the receiver to the
retort, a compressor condenser circuit connecting
the retort with the receiver, said compressor con
denser circuit being adapted for withdrawing gas
eous refrigerant from the retort and for deliver
ing liqueñed refrigerant to the receiver, and
means including a liquid pump for delivering
liquefied refrigerant from the retort to the re
ceiver.
8. The method of quick freezing food products
which comprises submerging the food in a lique
fied refrigerant in a closed system under pres
sure, continuously withdrawing gaseous refrig
erant, continuously returning liquefied refriger
ant at a substantially constant low temperature
until completion lof the freezing process and
thereafter withdrawing all of the liquefied re
frigerant from the system.
.
CHARLES T. WALTER.
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