US3031860A - Liquid cooling system - Google Patents

Description

May 1, 1962 H. A. MIDDLETON LIQUID COOLING SYSTEM Filed July 14, 1958 O/ M W H A TTORN 3,031,860 LIQUID COOLING SYSTEM Howard A. Middleton, 2627 McGee Traflicway, Kansas City, Mo. Filed July 14, 1958, Ser. No. 748,264 3 Claims. (Cl. 621S9) This invention relates to a liquid cooling system and more particularly to apparatus having a .relatively large drawofi rate over relatively short periods of time, which cannot be continuous; and a relatively small input rate over relatively long periods of time, which can be continuous.

Cold liquids are usually required wherever food is refrigerated and it would seem that apparatus for cooling liquids would usually be combined with apparatus for refrigerating food. Such liquid coolers have met with little success in the present state of the art however, little advance having been made from the water bottles and the like that are to be found in most home refrigerators and the water coolers of limited capacity that are to be found rates Patent in some commercial establishments. It would seem that-a satisfactory liquid cooler could be made by placing a tank inside a refrigerator, connecting the tank with a source of liquid under pressure and with a drawoif faucet. By actual test however it has been found that such devices often fail to secure an acceptable amount of cooling. To be acceptable the drawoif rate in homes and commercial establishments must be relatively fast, at least 1 ounce per second which equals 500 drops per second or 30 gallons per hour. By actual test however, in the present state of the art such a continuous flow of water cooled from 85 F. to 40 F. would require a relatively large refrigerating machine of 1 /2 to 3 horsepower whereas home and commercial refrigerators and conventional water coolers are usually equipped with relatively small refrigerating machines of not more than /2 horsepower which is about the size that can at the maximum be plugged into a conventional electric outlet.

Elongated upright tanks were tried since it was believed that the cold water would settle to the bottom of the tank and could be withdrawn from there. It was found however by actual test that such tanks did not operate as had been expected; the cold water did not always settle to the bottom, 33 F. water was found to be lighter in weight than warmer Water so the warmer water sometimes settled to the bottom. This problem is solved in the instant invention by cooling a relatively small flow of the liquid, typically as small as 1 drop per second or even less, over relatively long periods of time which can be continuous, accumulating the liquid in a refrigerated tank and subsequently withdrawing it at a relatively fast rate which cannot be continuous. The withdrawal rate must be at least 500 drops per second or 1 ounce per second or 30 gallons per hour to be acceptable in homes and commercial establishments where the liquid is drawn for human consumption.

Accordingly an important object of this invention is to make a liquid cooler so inexpensive that even the smallest user of cold liquids will be economically justified in employing it.

Another important object of this invention is to make a liquid cooling system that can be installed in a heat transfer relationship with the refrigerating apparatus of a conventional refrigerator so that additional refrigerating machines, cooling evaporators, heat exchangers, expansion valves, thermostats, solenoid valves and the like, that are costly and sometimes troublesome, will not be required.

Another important object of this invention is to make a liquid cooler that will eliminate the arduous labor of filling containers such as bottles, pitchers and the like with liquids and placing them in a refrigerator and the arduous labor of removing them after the liquids are cooled as well as eliminating the inconvenience of finding the containers empty when the need for the cold liquids ar1ses.

Another important object of this invention is to make a liquid cooler so constructed that all the liquid withdrawn therefrom will be adequately cooled.

FIGURE 1 illustrates apparatus constructed in accordance with a typical concept of the first form of this invention. FIGURE 2 illustrates a faucet used in this invention.

An insulated cabinet 12, having a rectangular opening in the front thereof is normally closed by a door 14 hingedly mounted by means 16 on cabinet 12 for swinging movement on a vertical axis. Door 14 is shown in the drawing in a position open at so that the interior of cabinet 12 is exposed. The interior of cabinet 12 is cooled by conventional refrigerating apparatus (not shown).

A liquid input mechanism is generally numerated 18. The liquid to be cooled flows from a source of liquid under pressure which may be a city water line 20, through a liquid conducting resistance 22, a manually operated valve 24, a liquid cooler 26, and a flexible conduit 28 into. a refrigerated tank 10. Flexible conduit 28 makes it possible for door 14 to swing on its hinges without interrupting the flow from cooler 26 into tank 10. Faucet 32 can be mounted on any wall of cabinet 12 in which case flexible conduit 28 can be a rigid conduit. Tank 10 may be disposed within cabinet 12 as well as on door 14- as shown. Resistance 22 is preferably an elongated capillary tube though other devices which are continuously open to liquid flow such as an orifice, a screw inside a tube or a throttle valve would be operable for the instant purpose. The liquid input rate is relatively slow, averaging typically 1 drop per second in the specific example of the invention described hereinafter.

Drawoff components consisting of conduit 34 and faucet 32 serve to withdraw the liquid that has been cooled and stored in tank 10. The drawoff rate must be relatively fast, about 500 drops per second, to be commercially acceptable.

Manually operated valve 36 is provided for testing.

In the first form of the invention, valve 38 is needed;-

it is assumed that faucet 32 is below the bottom of tank 10 so it might drain the tank, but conduit 34 slopes slightly upward from the tank so water can be trapped in the conduit which would prevent air from the atmosphere from flowing through the conduit into tank 10.

The operation of the apparatus is substantially as follows: Assuming that tank 10 contains no liquid but is filled with air at atmospheric pressure and drawolf is discontinued; a relatively slow liquid inflow from source 20 causes the liquid to be substantially cooled before it enters tank 10, the inflowing liquid compresses the air in tank 10 until the pressure therein is the same as the pressure at source 20 and liquid inflow then stops. Tank 10 now contains both cold liquid and compressed air and the system is static. When faucet 32 is opened the cold liquid is forced out by the compressed air at a relatively fast rate which must be about 1 ounce per second to be commercially acceptable. This is controlled by the way the user manipulates faucet 32. Upon the beginning of drawofi the pressure within tank It] falls to a lower pressure than the pressure at source 20 and liquid inflow again starts.

In a considerable period of time, typically 8 days, the

liquid in tank graduallyabsorbs the air that was initially entrapped therein. When this occurs, tank 10 can completely fill with liquid. Whenever there is liquid in tank), the pressure at its top will be'less than the pressure at its bottom due to the head of liquid or the Weight of the liquid. Now assuming that no way is provided for air from the atmosphere to enter the upper portion of tank 10, and tank 10 is completely filled with liquid and the air that was initially entrapped therein has all been absorbed by the liquid, now when the user opens faucet 32 in an attempt to withdraw liquid there will be virtually no flow from the faucet, the pressure inside the open faucet will be atmospheric pressure and consequently the pressure in the top of tank 10 will be less than atmospheric pressure, typically pound per square inch less. If air from the atmosphere could now enter the top of tank 10 it would cause water to flow from the faucet 32 at a commercially acceptable drawoif rate. So now if check valve 38 is provided, air from the atmosphere can flow therethrough into tank 10 and cause water to flow outof faucet 32 at a commercially acceptable rate. If all the liquid is withdrawn from tank 10, the tank will again be filled with air at atmospheric pressure as in the beginning.

[The operation of the second form of the invention is similar to the operation of the first form just described. In this second form, check valve 38 is not required, conduit 34 slopes downward from tank 10 and the conduit and faucet 32 are made relatively large without water traps or pockets in them. Now when the air that was initiallycntrapped in tank 10 has been absorbed by the water and the tank is completely filled with water, faucet 32 is opened and air from the atmosphere gurgles through faucet 32 and conduit 34 into tank 10 at the same time water gurgles out of tank 10 through conduit 34 and faucet 32 at a commercially acceptable drawo'ff rate. While FIGURE 2 shows a ground key faucet well known in the art, it is conceivable that other faucets such as an angle compression stop or a compression sediment faucet, well known in the art might be used here.

As used herein: Drops is meant as minims, of a fluid ounce. Rates is meant as units of volume per unit of time rather than as units of velocity. T ypically" is meant to refer to the typical example of the invention described hereinafter. Gurg'le is meant as an inflow of air and an outflow of liquid through the same devices at virtually the same time which may or may not be accompanied by an audible gurgling sound.

Liquid cooler 26 may be omitted and the liquid cooled in conduit 28 and tank 10, if some reduction in cooling capacity can be tolerated. The cooling of tank 10 below living space temperatures may not be necessaryif some temperature rise of the liquid in the tank can be tolerated.

In a typical example of the invention that was actually tested, the liquid was water from a river, the pressure at source was 90 pounds per square inch, resistance 22 was a capillary tube with a bore of .004 inch and a length of 4 inches, liquid cooler 26 had sufiicient capacity to cool the inflowing liquid to40 Fahrenheit and the pressure drop throughit and through conduit 28 was nil. Tank 10 had a diameter of 3% inches and a height of 7 inches and was disposed in an ambient having a temperature of 40 Fahrenheit. The apparatus was operative with intermittent drawofif of about 1 ounce per second and totaling about 1 gallon per 24 hour day. Inflow was virtually continuous at about 7 ounces per hour. The air entrapped initially "m 'tank 10 was completely absorbed in about 16 days by the liquid. "Faucet 32 and conduit34- had a bore of inch which was large enough to permit air to gurgle into tank 10 at'the same time water gurgled out, upon the infrequent occasions when the air in tank 10 had been absorbed by the water and it was necessary to replenish the air.

Itwill be appreciated that those skilled in the art could modify and change the precise structure disclosed for illustrative purposes without departing from the true spirit and intent of the invention. Accordingly it is to be understood that this invention shall be deemed as limited only by the fair scope of the claims that follow.

I claim:

1. The combination with a commercial pressurized water supply system operating at conventional commercial water pressure of apparatus constructed to provide a readily dispensable supply of water cooled to a temperature lower than the water temperature in said system, said apparatus comprising a pressure-tight container disposed in a cold ambient and initially containing air at atmospheric pressure, water conducting means connecting' said system with the interior of said container and providing a constantly open flow path from said system to said container whereby to cause compression of the air in said container to the same pressure as is present in said system, and at the same time partially fill said container with water, draw-cit means connected with the lower portion of said container and including an on-ofl dispensing valve having an effective maximum opening of one size, and so located with respect to said container that when said valve is opened, the compressed air in said container will force cooled liquid therethrough at a selected draw-off rate,.said conducting means including a restriction therein of substantially smaller size than the maximum opening of said dispensing valve whereby to limit the rate of flow of water to said container to a preselected maximum value which is substantially less than the flow rate through said dispensing valve, and means automatically operable to introduce air into said container whenever the pressure therein decreases to less than atmospheric pressure.

2. The combination as in claim 1 wherein said last named means is formed as a part of said valve mecha-' nism whereby air flows count'ercurrently through said valve mechanism into said container as cooled water flows outwardly from the container.

3. The combination as in claim 1 wherein said last named means comprises a one way check valve connected with the upper portion of said containe References Cited in the file of this patent UNITED STATES PATENTS 826,337 Kluhsmeier July 17, 1906 1,965,836 Heath July 10, 1934 2,270,383 Norton et a1. Jan. 20, 1942 2,435,774 Di Pietro Feb. 10, 1948 2,786,338 Wurtz et' al. Mar. 26, 1957

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