US3423950A - Vacuum cooling apparatus - Google Patents

Description

Jan. 28, 1969 J. T. REYNOLDS 3,423,950

VACUUM COOLING APPARATUS Filed Dec. 28, 1966 Sheet of 5 PRODUCE BUILDS UP FORCING\ ITSELF oowN INVENTOR JAMES T- REYNOLDS BY W' ATTORNEY S Jan. 8 96 J. 1'. REYNOLDS VACUUM COOLING APPARATUS 2 dr's Sheet Filed Dec. 28. 1966 20 55% @2308 2E8 BQESEB 55:28 mo 552 22c SQZEWDW. 838E INVENTOR JAMES T. REYNOLDS ATTORNEYS Jan. 28, 1969 J REYNOLDS 3,423,950 v I VACUUM COOLING APPARATUS Filed Dec. 28, 1966 Sheet 3 "or 5 Fl-G 3 INVENTOR JAMES T. REYNOLDS ATTORNEYS United States Patent 3,423,950 VACUUM COOLING APPARATUS James T. Reynolds, Scotch Plains, N.J., assignor to Croll- Reynolds Company, Inc., Westfield, N.J., a corporation of the United States of America Filed Dec. 28, 1966, Ser. No. 605,429 U.S. Cl. 62100 14 Claims Int. Cl. F25b 19/00, 13/06, 17/02 ABSTRACT OF THE DISCLOSURE Apparatus for cooling material which comprises a vacuum chamber and two legs adapted to form a liquid seal to the vacuum chamber. One of said legs acts as an entrance to the vacuum chamber and the other acts as an exit therefrom. A liquid is continuously flowed up one leg, through the vacuum chamber and down the other leg, said liquid being exposed to the vacuum while traveling through said vacuum chamber and being cooled by evaporation. Material to be cooled is passed along the path of the flowing liquid. The method of cooling by the apparatus is also disclosed.

Meat, poultry and fresh produce are generally precooled prior to refrigeration or shipment for marketing. Pre-cooling has been mainly done by batch systems such as in refrigerated chambers, single or multiple vacuum chambers, and with vacuum systems in conjunction with conventional refrigeration coils.

It is an object of this invention to provide a simple, continuous method for cooling produce and an apparatus for carrying out such a method.

It is a further object of this invention to provide a method and apparatus for vacuum cooling having a continously flowing liquid as the cooling and sealing medium.

Another object of this invention is to provide a method for cooling foodstuffs which comprises introducing the material to be cooled into a flowing liquid at atmospheric pressure, conducting said flowing liquid in contact with a vacuum, conducting said flowing liquid from said vacu um to atmospheric pressure, and separating the cooled material from said flowing liquid.

A further object of this invention is to provide a method for cooling foodstuflis wherein the cooling liquid is recirculated.

An additional object of this invention is to provide a method for cooling foodstuffs by means of countercurrent flow of liquid and foodstuffs.

These and other objects of my invention will become apparent as the description thereof proceeds.

The invention may be more readily understood by reference to the drawings which illustrate preferred embodiments, in which FIG. 1 is a cross-sectional schematic view in elevation showing one embodiment of the invention with continuously flowing fluid;

FIG. 2 is a cross-sectional view in elevation of an apparatus having an internal conveyor for conducting the produce through the apparatus;

FIG. 3 is a cross-sectional schematic view in elevation showing a third embodiment with a different fluid flow arrangement.

In FIG. 1, there is avertical ascending barometric leg 1 and a vertical descending barometric leg 2. Legs 1 and 2 are formed by outer shell 3 and by common divider wall 4 between the legs. Divider wall 4 terminates before the top 5 of shell 3-, forming 'vacuum space 6 above both barometric legs 1 and 2.

At the base of legs 1 and 2, shell 3 dips into tanks 7 and 8, respectively. Shell 3 terminates before the bottom of tanks 7 and 8. In tank '7, inlet 9 is provided, leading through seal 10 into ascending leg 1. In tank 8, descending leg 2 leads through seal 11 to outlet 12.

In operation, a vacuum is created in vacuum space 6 by jet vacuum means 13 leading to condenser 14 and to evacuator air pump 15. Water, brine, or other suitable fluid, is fed by recirculating pump 23 to opening -9 in tank 7 which is open to the atmosphere and rises in leg 1 under the vacuum maintained in vacuum space 6 by evacuator jet pump 13. A seal between the atmosphere and vacuum space 6 is thus formed. The vacuum in space 6 causes evaporation of fluid in the space and reduces the temperature in space 6 and the temperature of the water. The temperature of the circulating fluid and the foodstuffs being cooled is regulated by the vapor pressure of the fluid and the vacuum produced. When water is employed as the fluid, as is preferable, the vacuum is regulated so that the evaparation of the water under vacuum causes the temperature thereof to drop to about 33 F. In order to maintain the vacuum seal between vacuum space 6 above the barometric legs 1 and 2 and the atmosphere, it is preferable to have the legs extend about 34 feet above the water level of the water exposed to the atmosphere. Of course, if other temperatures of cooling are desired, simple calculation will determine the amount of vacuum desired and the height of partition 4. If the apparatus is to be utilized at varying temperatures, the upper part of the common divider wall 4 must be moveable. Water overflows at the top of divider 4 forming a flow weir 16, and flows down leg 2, through seal 11 and out outlet 12. The levels of water at 9 and 12 are maintained at slightly different levels to provide the overflow at weir 16.

Foodstuffs, such as mushrooms, berries, vegetables and the like, which have almost the same specific gravity as the liquid being circulated, are fed by a conveyor 17 to inlet 9. A baffle 18 guides the produce through seal 10 into ascending barometric leg 1. Many types of produce are lighter than water and will rise up leg 1 due to their buoyancy. Produce which is slightly heavier than water will be swept up the leg by the flow of water which can be regulated as desired. The movement of water through seal 10 will convey the produce into leg 1. Produce in leg 1 is gradually cooled as it rises in leg 1 and falls down leg 2. In addition some cooling is effected on any surfaces exposed to the vacuum in vacuum space 6. Produce passes from leg 1 into leg 2 by the action of the fluid flowing over weir 16. The weight of the produce and motion of the water in descending leg 2 carry the produce down and out through seal 11 and outlet 12 to a second conveyor 19. Baflle 20 aids in guiding produce through seal 11.

The fluid leaving outlet 12 overflows into receiver 21 through perforated trough 34 and is then recycled by line 22 and pump 23 to inlet tank 7.

Many types of foodstufls, particularly those which have structures which trap air, such as mushrooms, peaches and some berries are more buoyant than the fluid employed, particularly when it is Water. However, on exposure to vacuum the trapped air is removed and replaced by water, thus lowering this buoyancy to a point where the material is heavier than water. The apparatus of FIGURE 1 takes advantage of this phenomena is that the natural tendency of the buoyant produce is to rise in leg 1 and after rernoval of this buoyancy, to sink in leg 2.

Since some produce may not move solely by motion of fluid, however, the invention includes the use of any suitable means, not shown, within the apparatus for aiding in movement of the produce such as paddle wheels or flighted conveyors.

The vacuum pump elements 13, 14 and 15 are steam jet vacuum apparatus well known in the art, and since they form no part of this invention, they are not described in detail here.

As indicated above many types of foodstuffs have structures which trap air and, on undergoing the vacuum cooling process of the invention, the air is replaced by cooled water. This results in adding weight to the produce which is, of course, of advantage in products sold by weight. However, a further advantage of the wetted produce is that in a subsequent freezing process, the heat transfer is improved due to the absence of the trapped air layer which acts as an insulating layer. The process of vacuum cooling of the invention is therefore an economical pre-freezing step in the freezing of fruits and vegetables.

The vacuum cooling process of the invention can also be used to advantage in combination with the process of food preservation, particularly with meat, known as micronization. In this process meat is soaked in a solution of a preservative. If the solution of the preservative is utilized as the cooling liquid in the vacuum cooling process of the invention, a vacuum impregnation of the foodstuff occurs which impregnation is quicker and more effective than merely soaking the foodstuffs as is done by the prior art.

In FIG. 2, a different embodiment of the invention is shown which is essentially the same as in FIG. 1. Like elements are numbered the same as in FIG. 1. FIG. 2, the barometric legs 1 and 2 are completely separated. Vacuum space 6 is elongated. A conveyor 24 is provided for conveying the produce, for example, chickens which may be hung from the conveyor. Fluid is fed at point 25 to the produce outlet side 12 in tank 8, passes through seal 11 and rises in leg 2. The fluid flows in vacuum space 6 to leg 1 and down, through seal to produce inlet 9 in tank 7. Weir 26 maintains the proper flow levels of fluid which discharges to tank 27. The fluid is then recirculated to feed by means of conventional pump and piping not shown.

As shown in IG. 2, the produce can be submerged during the entire path through the cooling apparatus, or it can be removed from the fluid while in vacuum space 6. If the produce is exposed to the vacuum, a further cooling by surface evaporation occurs.

The embodiment of FIG. 2 thus provides countercurrent flow of fluid and produce. This arrangement provides for a more even temperature distribution since the uncooled produce rising in leg 1 comes first into contact with water cooled in vacuum space 6.

A slightly different embodiment of the invention is illustrated in FIG. 3. Reference numerals for like elements are the same as in FIGS. 1 and 2. The apparatus of FIG. 3 uses some principals of FIG. 1 and some from the apparatus of FIG. 2. FIG. 3 shows separate ascending leg 1 and descending leg 2 as in FIG. 2. However, fluid flow is concurrent with the produce flow from inlet 9 to outlet 12. The vacuum seal is formed by closed vessel 30 at the lower end of legs 1 and 2 instead of by separate tanks 7 and 8 as in FIG. 1. Fluid level is maintained by means not shown of a conventional float type. As a further improvement, Condenser 14 discharges through leg 33 to the closed vessel 30, thus conserving liquid.

The apparatus of FIG. 3 was designed particularly for the cooling of mushrooms utilizing water as the fluid. The vacuum maintained in vacuum space 6 is sufficient to cool water to 33 F. The difference between the water level in the barometric legs 1 and 2 and the water level in the closed vessel 30 is about 34 feet. As previously indicated fresh mushrooms retain sufficient entrapped air to render them buoyant in water. A conveyor 31 is therefore required to submerge them and place them at the bottom of leg 1 where they rise due to their natural buoyancy, as they reach the top of leg 1 they lose entrapped air and their specific gravity becomes about 1.05 causing them to fall through leg 2. At the bottom of leg 2 they tend to settle to the bottom of vessel 30 and must be removed therefrom by a conveyor which can be the same conveyor 31 or another conveyor. The mushrooms in rising and settling in legs 1 and 2 cause the water to fOllow along,

thus eliminating the need for a pump or other force to recirculate the water.

The following specific example is given to illustrate the operation of the apparatus of the invention, but it will be understood that the invention is not limited thereto.

Example I Into an apparatus of the type indicated in FIG. 3 having a vacuum space 6 and two 16" legs approximately 34 in length, 10,000 pounds of mushrooms per hour were discharged into the inlet for the up leg of the cooler by means of conveyor 31. A pressure of 4.6 mm. absolute was maintained in the vacuum space by means of the 14 x 10 booster 13. The mushrooms flowed up the ascending leg of the apparatus by their buoyancy and as they become water-logged, settled into the descending leg 2. The mushrooms propelled a flow of water up the ascending leg 1 and down the descending leg 2. A temperature of approximately 33 F. was thus maintained in the circulating water and approximately 10,000 pounds per hour of mushrooms on the incoming weight basis were cooled to 33 F. and discharged on from the conveyor 31. Thereafter they were conveyed to the packing room.

The apparatus of the invention is particularly adaptable to the cooling of produce that traps air at its surface, such as mushrooms, peaches or lettuce, since the air would impede heat exchange. Vacuum cooling removes the air barrier allowing the cooling fluid to have its most effective contact.

It is apparent that the invention provides a simple and effective way for continuously conveying meat, poultry and fresh produce from the atmosphere into a vacuum cooling space and out again using a flowing liquid both as the vacuum space seals and as the cooling medium. In addition, the invention provides a method and apparatus for cooling produce where the cooling liquid is both flowing and recirculated to effect an increase in the cooling efficiency. Furthermore, all liquid evaporated from the circulating liquid can, if desired, be condensed and returned to the cooling system as shown in FIG. 3.

Although certain specific embodiments and preferred modes of practice of the invention have been described, it Will be understood that this is solely for purposes of illustration and that various changes and modifications may be made in the invention without departing from the spirit of the disclosure and the scope of the appended claims.

I claim:

1. A method for cooling which comprises introducing the material to be cooled into a unidirectional, continuously flowing liquid at atmospheric pressure, conducting said material within said liquid to a vacuum zone, exposing said continuously flowing liquid and said material to the vacuum within said vacuum zone whereby some of said liquid is evaporated and said continuously flowing liquid is cooled, conducting said material within said liquid from said vacuum zone to atmospheric pressure, separating the cooled material from said continuously flowing liquid and returning said continuously flowing liquid to said introducing step.

2. The method of claim 1 wherein said material to be cooled is vegetable produce.

3. The method of claim 1 wherein said material to be cooled is introduced into said continuously flowing liquid, passed through said vacuum zone and conducted from said vacuum zone to atmospheric pressure by means of a conveyor.

4. The method of claim 3 wherein said material to be cooled is conveyed countercurrently to the flow of said continuously flowing liquid.

5. The method of claim 1 wherein said material to be cooled flows as :an admixture with the flow of said continuously flowing liquid.

6. The method of claim 5 wherein said material to be cooled is heavier than said liquid but contains suflicient air to be buoyant in said liquid and said air contained in said material to be cooled is removed in said vacuum zone.

7. The method of claim 6 wherein said continuously flowing liquid is caused to flow by the presence of said material to be cooled.

8. The method of claim 7 wherein said material to be cooled is mushrooms.

9. The method of claim 1 wherein said liquid is water.

10. Apparatus for cooling material comprising a vacuum chamber containing a continuously flowing liquid, entrance means to form a liquid seal for said vacuum chamber, exit means to form a liquid seal for said vacuum chamber, said entrance means and said exit means to form a liquid seal for said vacuum chamber being in liquid connection through said vacuum chamber, means to continuously flow liquid at atmospheric pressure into said entrance means through said vacuum chamber and back through said exit means to atmospheric pressure, means to impress a vacuum pressure on said vacuum chamber, said vacuum being suflicient to evaporate some of said liquid and to lower the temperature thereof, and means to introduce a material to be cooled at atmospheric pressure into said continuously flowing liquid passing through said vacuum chamber and to remove cooled material from said continuously flowing liquid after passing through said vacuum chamber, at atmospheric pressure.

11. The apparatus of claim 10 including conveying means to move said material through said apparatus.

12. The apparatus of claim 10 including means to recirculate said liquid.

13. The apparatus of claim 12 wherein said means to recirculate said liquid is said material to be cooled.

14. Apparatus for cooling material which comprises means to continuously flow a liquid in a path from atmospheric pressure to vacuum pressure and back to atmospheric pressure, said vacuum pressure being suflicient to evaporate some of said liquid and lower the temperature thereof and means to introduce material to be cooled at one atmospheric end of said liquid path and to remove said material cooled from the other atmospheric end of said liquid path.

References Cited UNITED STATES PATENTS 2,787,141 4/1957 Julius 62-375 WILLIAM J. WYE, Primary Examiner.

US. Cl. X.R.

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