Eutectic solution and CO.sub.2 snow cool tank

A vented cold tank is provided and partially filled with a eutectic solution. CO.sub.2 snow forming structure is provided within the interior of the tank above the level of eutectic solution therein and liquid CO.sub.2 injection structure is provided in an lower portion of tank below the level of eutectic solution and arranged to create circulation of the eutectic solution within the tank including generally opposite upper and lower horizontal components of movement and generally opposite vertical components of movement of the solution within the tank. The CO.sub.2 injection structure also is operative to educt a portion of the circulating solution from a lower portion of the interior of the tank adjacent the bottom thereof, mix CO.sub.2 snow with the educted portion of solution, and downwardly direct the mixed CO.sub.2 snow and educted portion of solution on to an area of the surface of the solution within the tank substantially at the beginning of the upper horizontal component of eutectic solution circulation within the tank.

CROSS REFERENCE TO RELATED APPLICATION 
This application discloses an improvement over the COOL TANK CONSTRUCTION 
FOR EUTECTIC SOLUTION AND CO.sub.2 SNOW disclosed in my prior U.S. patent 
application Ser. No. 07/190,109, filed May 4, 1988 (now U.S. Pat. No. 
4,848,095) the disclosure of which is incorporated herein by reference. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a closed, but vented, receptacle contructed of 
good heat transfer material and partially filled (approximately 1/3) with 
a eutectic solution. The upper portion of the interior of the receptacle 
includes CO.sub.2 spray head structure for forming CO.sub.2 snow therein, 
which snow may fall down upon the surface of the eutectic solution, and 
the lower portion of the interior of the receptacle includes structure for 
creating a predetermined path of circulation of eutectic solution within 
the approximate 1/3 lower portion of the receptacle, which circulation of 
eutectic solution is accomplished by jet discharging liquid CO.sub.2 into 
the inlet end portion of a circulation pipe including a horizontal leg 
disposed in the bottom of the receptacle and opening outwardly of one side 
wall of the receptacle adjacent the bottom thereof, a vertical leg 
extending upwardly from the end of the horizontal leg opening outwardly of 
the receptacle side wall and an upper L-shaped leg extending inwardly 
through an upper portion of a side wall of the tank above the level of 
eutectic solution therein and terminating inwardly in a down turned outlet 
end portion, the down turned outlet end portion being disposed above the 
surface of the eutectic solution in an area thereof remote from the inlet 
end portion of the first mentioned horizontal leg of the circulation pipe. 
All portions of the circulation pipe disposed exteriorly of the receptacle 
being covered by a suitable insulating covering. 
2. Description of Related Art 
My prior U.S. Pat. No. 4,848,095, dated July 18, 1989 discloses all of the 
instant invention, except for the circulation pipe of the instant 
invention. 
SUMMARY OF THE INVENTION 
The instant invention provides an improved method and apparatus for 
obtaining, in a cold tank or the like, appreciably greater heat absorbing 
capacity through the utilization of a given amount of liquid CO.sub.2. In 
addition, the instant invention provides an apparatus and method for more 
rapidly chilling the eutectic solution within a cool tank or the like. 
The main object of this invention is to provide a more efficient manner of 
cooling the eutectic solution within a cool tank through the utilization 
of liquid CO.sub.2. 
Another object of this invention is to provide a cool tank "charging" 
apparatus and method which does not require any outside power source other 
than a source of liquid CO.sub.2 under pressure. 
A final object of this invention to be specifically enumerated herein is to 
provide a cold tank in accordance with the preceding objects and which 
will conform to conventional forms of manufacture, be of simple 
construction and dependable in operation so as to provide a device which 
will be economically feasible, long-lasting and relatively trouble free in 
operation. 
These together with other objects and advantages which will become 
subsequently apparent reside in the details of construction and operation 
as more fully hereinafter described and claimed, reference being had to 
the accompanying drawings forming a part hereof, wherein like numerals 
refer to like parts throughout.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now more specifically to the drawings the numeral 10 generally 
designates a cool tank such as that disclosed in my prior U.S. Pat. No. 
4,848,095, dated July 18, 1989. The cool tank 10 includes large area 
opposite side walls 12 and 14 and smaller area opposite end walls 16 and 
18. The end walls 16 and 18 interconnect corresponding ends of the side 
walls 12 and 14 and the latter include vertically extending corrugations 
to increase the surface area thereof. Further, top and bottom walls 20 and 
22 extend between and interconnect the upper and lower marginal portions 
of the walls 12, 14, 16 and 18. The interior of the tank 10 is 
approximately 1/3 filled with any suitable eutectic solution 24 (for 
instance, a 3:1 mixture of water and propylene glycol having a freezing 
temperature of approximately -20 degrees F.). 
The lower portion of the tank 10 includes transversely extending heat 
exchange air-flow tubes 26 extending between and sealingly secured through 
the side walls 12 and 14. 
A liquid CO.sub.2 header pipe 28 is disposed in the upper portion of the 
tank 10 and extends longitudinally thereof. The header pipe 28 opens 
through the end wall 16 from a suitable supply of liquid CO.sub.2 under 
pressure. Further, a CO.sub.2 supply line or pipe 30 enters into the upper 
portion of the interior of the tank through the end wall 18 and is 
immediately downwardly directed as at 32 to a position closely adjacent 
the bottom wall 22. The lower end of the supply line 30 includes a 
horizontally directed leg 33 extending lengthwise of the bottom wall 22 
and which projects into the open inlet end portion 34 of a first 
horizontal leg 35 of a eutectic solution circulation pipe 36. 
The horizontal leg 35 of the circulation pipe 36 projects outwardly through 
the end wall 16 as at 37 in fluid tight sealed engagement therewith and 
terminates in an upwardly directed leg 38 of the circulation pipe 36 which 
projects above the level 4 of eutectic solution 24 in the tank 10. The 
upwardly directed leg 38 terminates upwardly in an L-shaped outlet end 
portion 39 including a horizontal leg 40 opening inwardly through the end 
wall 16 as at 41 in fluid tight sealed engagement therewith and 
terminating inwardly in a downwardly directed leg 42 spaced above the 
level 43 immediately inward of the end wall 16 and considerably remote 
from the inlet end 34 of the circulation pipe 36. The horizontal leg 33 of 
the supply line 30 terminates in a upwardly directed outlet end 44 within 
the leg 38 and at a level spaced below the level 43. 
All portions of the circulation pipe 36 disposed exteriorly of the tank 10 
and the end wall 16 are covered with suitable insulation 45 for a purpose 
to be hereinafter more fully set forth. 
The header pipe 28 includes a plurality of downwardly directed discharge 
lines 50 spaced therealong and each discharge line 50 is communicated with 
one or more spray discharge outlets 52 each disposed within a downwardly 
opening horn 54. Spray discharge of liquid CO.sub.2 under pressure from 
the outlets 52 results in CO.sub.2 snow being formed within the horns 54 
and dropping downwardly onto the surface of the eutectic solution 24. In 
addition, the spray discharge of liquid CO.sub.2 from the outlet end 44 of 
the supply line 30 in an upward direction in the leg 38 of the circulating 
pipe 36 acts as an eductor to draw eutectic solution 24 into the inlet end 
portion 34 of the circulation pipe 36 and for eutectic solution 24 to be 
driven upwardly through the leg 38 of the circulation pipe 36 and out 
through the outlet end portion 39 through the open lower end of the 
downwardly directed leg 42. Of course, the circulation of eutectic 
solution through the circulation pipe 36 causes the circulation of the 
eutectic solution 24 within the tank 10 as indicated by the arrows 56 
shown in FIG. 2. In addition, additional CO.sub.2 snow is formed by the 
CO.sub.2 being discharged from the downwardly directed leg 42. 
The circulation as indicated at 56 causes CO.sub.2 snow already formed to 
mix and circulate with the eutectic solution 24 and to quickly reduce the 
temperature thereof to a level nearing the temperature of the CO.sub.2 
snow without excess build-up of CO.sub.2 snow on the surface of the 
eutectic solution 24. 
When the eutectic solution 24 has been sufficiently chilled to form a 
slush-like mixture, the desired chilling operation is almost completely 
accomplished and the discharge of liquid CO.sub.2 from the header pipe and 
the supply line 30 is allowed to continue for only a short time thereafter 
(according to the size of the tank 10 and the rate of discharge of liquid 
CO.sub.2). 
A cooling tank 10 is primarily designed to be used in insulated truck 
bodies (although the tank 10 may be exteriorly mounted) and a certain 
amount of time is required together with a certain amount of liquid 
CO.sub.2 in order to fully chill the tank 10 and the eutectic solution 24. 
As is accomplished by the tank disclosed in my prior U.S. Pat. No. 
4,848,095, if the liquid CO.sub.2 supplied to the header pipe 28 and the 
supply line 30 comprises the same supply of liquid CO.sub.2. Therefore, as 
the eutectic solution 24 reaches a slush-like consistency and the supply 
line 30 experiences a resultant build-up of resistance pressure, excess 
pressure in the supply line 30 is avoided by such excess pressure being 
vented through the header pipe 28 to form additional CO.sub.2 snow on top 
of the eutectic solution 24. 
In addition, it is important that the upwardly directed leg 38 of the 
circulation pipe 36 be disposed exteriorly of the tank 10 in order to 
avoid excess cooling of that portion of the circulation pipe 36 into which 
the liquid CO.sub.2 is discharged, which excess cooling could cause the 
circulation pipe 36 to be prematurely blocked by substantially solidified 
eutectic solution 24. Of course, the insulation 45 is provided to avoid 
excess heat absorption by the upwardly directed leg 38 of the circulation 
pipe 36 exteriorly of the tank 10. 
The rate of CO.sub.2 supplied to the supply line 3 is greater than the rate 
of CO.sub.2 supplied to the header pipe 28. Further, the upper portion of 
the tank 10 is vented to the ambient atmosphere through vent tube 60. 
The foregoing is considered as illustrative only of the principles of the 
invention. Further, since numerous modifications and changes will readily 
occur to those skilled in the art, it is not desired to limit the 
invention to the exact construction and operation shown and described, and 
accordingly, all suitable modifications and equivalents may be resorted 
to, falling within the scope of the invention.