US2191518A - Means of refrigeration - Google Patents

Description

Feb. 27, 1940. l F CLERC 2,191,518

MEANS 0F REFRIGERATION Filed June 17. 1938 4 Sheets-Sheet 2 a, INVENTOR. Leonard Ff Clerc,

Feb. 27, 1940. L.. F. CLERC MEANS OF REFRIGERATION Filed Jima 17, 19:58

4 Sheets-Sheet 3 c R.r mk MC /..O T MFM/M d?, r a n O e L F. CLERC 191,518

MEANS 0F REFRIGERATI ON Fehn 27, 1940.

Filed June 17, 1938 4 Sheets-Sheet 4 U0 6 5 Fig@ @r INVENTOR. Leon ard PC l@ rc ATTO FY.

Patented Feb. 27, 1940 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to refrigeration apparatus and methods and'has particular reference to the refrigeration of food stuffs, although the principles involved may be vreadily applied to any refrigerating purpose.

The principle object of the invention is to generally improve the art of refrigeration.

Another object of the invention, is the provision of a method and apparatus, which may be l0 eiliciently utilized in the making, handling, and

storage of frozen foods.

A further object of the invention, is thc provision of a method and apparatus, with which may be advantageously employed a solid refrigerant, such as solidified (CO2) or dry ice, thereby obviating many diiculties now encountered in the use of refrigerating devices, which employ brine tanks and mechanical refrigeration.

Another object of the invention, is the provision of apparatus which may employ a solid refrigerant, in such manner that the deterioration, and output of the refrigerant,vmay be automatically controlled, so as to effect greater eiliciency.

A further object of the invention, is the provision of a refrigerating device, having a capacity to effectively achieve much lower temperatures than devices now in commercial use, and do it in a relatively shorter period of time.

A further object of the invention, is the pro- 30 vision of a device, Which will effect a greater amount of refrigeration per unit of air moved within a given confined space.

A still further object of the invention, is the provision of refrigerating apparatus, having a very flexible refrigerating capacity, with equal eiciency, throughout its entire range.

Another object of the invention, is the provision of a device which will uniformly distribute refrigeration to all parts of a conned space, which it n is desired to refrigerate.

Further objects and advantages of the invention will appear as the description proceeds, reference being made from time to time to the accompanying drawings, which form a part of this disclosure, in which drawings:

Fig. 1 is a front view of a device embodying my invention, with parts broken away and partly in section.

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal section taken on the line 3-3 of Fig. 1.

Fig. 4 is a diagrammatic view, with parts in perspective, illustrating part of the heat exchange mechanism, and the control means.

(Cl. (i2-91.5)

Fig. 5 is a perspective view, With parts broken away, illustrating the construction of the heat exchange unit.

Fig. 6 is a horizontal section taken on line 6 6 of Fig. 5.

Fig. 7 is a diagrammatic view of the exhaust gas coil, lines and controls.

Fig. 8 is an end view of the refrigerant indicating mechanism.

Fig. 9 is a View, partly in section, of a modified lo form of heat exchange unit.

Fig. 10 is a section taken online III-I0 of Fig. 9.

Fig. 11 is a section taken on line II-II of Fig. 10.

Fig. 12 is a perspective view of one of the ele- 15 ments comprising the heat exchange unit illustrated in Figs. 9 to 11.

Referring now more particularly to the drawings, it will be understood that in the embodiment of the invention herein disclosed, the reference 20 character I5 indicates a cabinet or box in which is housed the device embodying my invention. The cabinet I5 may be made of any desirable material and, is heat insulated, as at I6, and provided with doors I'I and I8, (Fig. 2), which doors 25 respectively open into the mechanical compartment I9 and the storage compartment 20. Housed Within the compartment I9, is a smaller, gas tight container 2I, in the bottom of which is mounted the heat exchange unit 22, which Will 30 be described more fully hereinafter. The container 2l is adapted to receive a solid refrigerant 23, such as dry ice, which is arranged to rest on the heat exchange unit 22. The solid refrigerant 23, may be introduced to the container 2| 35 through a door 24 (Fig. 2) in the container 2l and the door I'I of the cabinet I5. The door 24 is sealed by a gasket 25, and held in position by means of the bolts 26 and nuts 21.

A walking plate 28 (Fig. 1) i s arranged within 40 the container 2| and is adapted to cover the topof the solid refrigerant 23. Secured to the underside of the Walking plate 28 is an insulating pad 29, which is preferably made of felt. The pad 29 is provided with depending curtains 30, which are l intended to insulate the solid refrigerant 23, on the sides. This insulation about the refrigerant tends to retard its action on all sides except where it is in contact with the heat exchange unit 22.

The Walking plate 28 is supported by chains 50 3I, which are secured at one end to the plate 28 and at the other end of sprockets 32, the latter being supported above and outside the container 2 I, in gas tight housings 33. The sprockets 32 are mounted on a common shaft 34, and are arranged tight container 2|.

to hold the walking plate 28 in horizontal alignment as it descends with the deteriorating solid refrigerant 23.

An indicator 35 (Figs. 2 and 8) is positioned at the end of the shaft 34, which extends to the outside of the cabinet I5, and shows at all times how much solid refrigerant remains in the contalner 2|.

A blower 36 is mountedwithin the compartment I 9, and may be supported on top of the container 2| and secured thereto by any suitable means. An electric motor 31 is adapted to drive the blower 36. The motor is preferably mounted in a separate compartment 38, which is cooled by means of the louvres 39, which open to atmosphere. In some applications I prefer to insulate the blower 36, by imbedding it in a good heat insulator, within the compartment I9. This reduces to a minimum any tendency of moisture to condense on the blower, because of air getting to it from the motor compartment 38.

The blower 36 is connected to air intake pipes 39 (Fig. 4) the latter having intake ports 40 positioned near the bottom of the storage compartmen 20. The air is expelled from the blower 36 into the air intake pipes 4I, which in turn communicate as at 42, with the interior of the heat exchange unit 22. As shown by the arrows in Fig. 6 the air enters the heat exchange unit 22 at 42 and travels back and forth inside the unit 22 until it reaches the outlet 43, which communicates with the air exhaust pipes 44, which carry the air to the upper interior of the storage compart ment 20, where it is distributed through a series of apertures 45. The apertures 45 diminish in size as the ends of the pipes 44 are reached, this tends to equalize the air pressure and distribute it uniformly throughout the interior of the cabinet.

An important feature of my invention resides in my ability to retard the deterioration of the solid refrigerant and to control its effective cooling output. I do this by controlling the exhaust of the refrigerant. It will be remembered that the solid refrigerant 23 is confined within a gas I provide a gas exhaust line 46, which communicates with the interior of the container 2| and carries off the C02 gas, which is generated in the container. 'The solid refrigerant deteriorates much slower by maintaining a pressure in the container. This is accomplished by providing safety valves 41 and 49 (Fig. 1) in the line .46. I prefer to maintain a pressure of approximately 25 lbs. per square inch in the container 2|, although the pressure will vary in different installations.

In order to getthe maximum refrigerating efiiciency from the deteriorating solid refrigerant, I also utilize the CO2 gas as a cooling medium by running it through a coil 48, which extends through the storage compartment 20. I provide the second valve 49 (Fig. '7) at the end of the coil 48, so that the desired pressure may be maintained in the coil 48. The valve 41 is preferably set at 15 lbs. and the valve 49 is preferably set at 25 lbs., so that a pressure of 25 lbs. may be maintained throughout the container 2|, and coil 48.

- In order to precool the cabinet I5, I provide a,

shut off valve 50, which enables me to by-pass the gas around the valve 41 into the coil 48 and hence through the valve 49 and the pipe 5I, to the atmosphere. I provide a pressure gauge 52 in the gas exhaust line 46, so that the pressure may be checked at all times.

I have found that the deterioration of the solid i tube.

refrigerant is faster while the blower 36 is forcing air through the heat exchange unit 22, and the deterioration diminishes when the blower 36 stops. 'I'he faster the ice deteriorates, the faster the gas pressure builds up in the line 46, and when the desired gas pressure is reached deterioration of the solid refrigerant is slackened.

In order to control the operation of the blower 36, and the output of the device I provide an electric circuit 54 (Fig. 4) which is connected to a source of electric current (not shown). The operation of the motor 31 is controlled by a thermostatic element 55, which actuates the mercury switch 56 to open and close the circuit 54. The thermostatf55 is preferably set to operate between the range of zero and 3 below zero. The lights 51, one of which is green, and the other red, are also positioned in the circuit 54, to indicate whether or not the blower is operating. Any combination of lights may be used, but I prefer to employ the red light to indicate when the motor 31 is running the blower 36, and the green light to indicate when the motor is not running. In other words the red light will go on when the temperature inside the cabinet I reaches zero, and will remain on until it drops to 3 below zero, and the green light will be on when the temperature is below 3 below zero.

The construction of the heat exchange unit 22 (Fig. 5) has particular significance in the eflicient operation of my device. I prefer to construct it with tubes made of a highly conductive metal, each tube having a substantially square cross section. This affords the maximum flat surface area for contact with the solid refrigerant, and enables me to use two tiers of tubes in close relation. In that way there are no voids between the tubes and there results a maximum of conductivity between the tiers. Constructed in this manner the air can travel a comparatively long distance through the tubes and be subjected to a very low degree of temperature all the way. Another advantage results from this construction. As the airis forced from tube to tube it is made to travel around sharp corners, which causes it to be agitated and mixed. It is a well known fact that air traveling through a straight tube would not have the same temperature at the center of the stream as it would have at the edge of the stream. Because of friction, the air at the edge of the stream would travel slower and would have more time to absorb heat or cold from the walls of the By the same token the 'air at the center of the stream would be warmer, so that there would not be any uniformity in the temperature of the air, particularly if the tubes were of comparatively large diameter. With mydevice the air is agitated and the stream is broken at the turns, so that the cold and less cold air are thoroughly mixed. I have also found that `more effective cooling of the air results if the air is forced through the tubes under a constant pressure.

In Fig. 5, I have illustrated the preferred form of heat exchange unit 22. lIn this embodiment the tiers of tubes are in contact with one another and the ends of the tubes are flush, the connections between the respective tubes being made through ducts formed in the end members 22a.

The end members 22a may be castings or stampings. The individual tubes are first welded or soldered at their ends, to plates 22h, which have square apertures formed therein, corresponding to the inside dimensions of the tubes. The end members 22a, are then welded or soldered to the plates 22h, to effect air tight joints.

In Figs. 9 to 11, I have illustrated a modified form of heat exchange unit. In this embodiment the tiers of tubes are separated by the space 6l). This is done to enable the unit to be submerged in a heat transfer agent such as alcohol'or the like. There are some applications where such procedure is advisable due to the limitation of horizontal space. The operation of the unit, however, is the same.

In the construction shown in Figs. 9 to 11, the tubes are formed of channel members (Fig. 12), Which have cut out portions 6I at opposite'ends to provide communication between the tubes. The channel members, Fig. 12, are then arranged inside the top and bottom members 62 and 63, Fig. 11, to form the unit. In this embodiment I prefer to divide the unit at the center, as at 64, so that only half of the air stream passes through each half of the unit. The air stream is divided by the two way intake tting 65.

The eiTective temperature of dry ice is 109 below zero. With my device I have found that I could introduce air to the heat exchange unit at '70 or room temperature and have it emerge at below zero instantaneously. In `this instance the air traveled only a distance of approximately 27 feet in the unit. By increasing the distance of travel to '72 feet, I can take air in at 76 above zero, and bring it out at 80 below zero. The quantity of solid refrigerant on the unit makes no diierence so long as the upper surface area, of the unit is covered. In other words a piece of dry ice, one inch thick is as effective as a piece ten inches thick.

The heat exchange is so quick with my device, that it is possible to hold the temperature in the cabinet to which a 3 variation. 'I'his is very important when it is considered that brine and other systems now in use vary as much as 10 to 15. In the production of frozen foods it is important that the foods be frozen quickly. With this device I can freeze an equal quantity of food in a fraction of the time required of other devices now in use.

I have discovered that in the operation of this device, and while employing such comparatively low temperatures, that there is no tendency whatsoever for frost to accumulate on the outside or inside of the heat exchange unit 22. This is particularly advantageous, as it permits the device to be used for longer periods of time, Without the necessity of defrosting.

I have found this device so ecient, that it is possible to greatly change the temperature of the air in a comparatively largo space in a very short period of time. With this device, it is possible to lower the temperature in an ordinary store cabinet 3 in approximately one minute. The changing of the temperatures of the air in larger spaces may be effected with corresponding eniciency.

Having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a device of the character described, the combination of a space to be cooled, a compartment insulated from said space, a container in said compartment, a heat exchange unit positioned in the bottom of said container, a solid refrigerant in contact with and resting upon said heat exchange unit, means to force air through said heat exchange unit and into said space to be cooled, a cooling coil positioned in said space to be cooled, said coil being connected to said refrigerant container and adapted to draw 01T the gas resulting from the sublimation of the solid refrigerant, said gas and said coil being adapted to serve as an ancillary refrigeratng medium in the space to be cooled, and means to regulate the pressure in the container, in the connecting line, and in the coil.

2. In a device of the character described, the combination of a space to be cooled, a compartment insulated from said space, a container in said compartment, a heat exchange unit positioned in the bottom of said container, a solid refrigerant in contact with and resting upon said heat exchange unit, means to force air through said heat exchange unit and into said space to be cooled, a cooling coil positioned in said space to be cooled near the discharge openings in said air means, said' coil being connected to said refrigerant container and adapted to draw oi the gas resulting from the sublimation of the solid refrigerant, said gas and said coil being adapted to serve as an ancillary refrigerating medium in the space to be cooled, and means to regulate the pressure in the container, in the connecting line, and in the coil.

LEONARD FRANK CLERC.

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