High Efficiency Method and Apparatus for Making and Dispensing Cold Carbonated Water

1. Field of the Invention

This invention pertains to a high efficiency method and an apparatus for making, cooling and dispensing carbonated water or beverage utilizing discrete precool and final coolers supplied by a common refrigerant source; the discrete precooler is of very high thermal efficiency and BTU capacity and precools the water only to an intermediate temperature of about 45 degrees F. (7 degrees C.) and an ice bank final cooler final cools the water to as close to freezing as is possible with great accuracy without freeze-up.

Prior and existing carbonated beverage coolers of high capacity have been devised. They typically have a relatively large compressor and a single evaporator. Some have plural compressors and evaporators.

One type of evaporator system puts the evaporator in direct contact with the water. This is the most efficient of all cooling systems, but this system has suffered from failures due to freeze ups or else the dispensed water has been too warm. The crux of the problem with this type of cooling system is that it cannot be accurately controlled and as the water temperature approaches freezing, and the unit eventually freezes up and becomes plugged with ice or it bursts. In order to avoid these failures, users have set the water temperature higher and the device then dispenses warm drinks which are not acceptable to the soft drink entities or the consuming public. This type of device was fairly popular in the 1940's and 1950's, but has not seen significant use since then because of its history of failure and problems.

Ice bank refrigeration systems are now common and are the most frequently used cooling systems in the cooling and dispensing of carbonated water and soft drinks. A typical ice bank beverage cooler is disclosed in R. T. Cornelius' U.S. Pat. No. 3,056,273. This type of cooler is very accurate and repetitive and it will cool a beverage to very close to freezing (32 degrees F. or 0 degrees C.) reliably and without freeze up. However, the system sacrifices thermal efficiency and its dispensing capacity is limited by the amount of ice it has. This type of unit builds up its ice bank, and uses the inventory of ice to cool beverage. As the ice thickness on the evaporator builds up, the output of the refrigeration system decreases. The response of the refrigeration system to dispensing is slow and there's a considerable time lag before the compressor responds to dispensing and consumption of the ice bank.

Multiple compressor systems are well known and are typically used in semi-frozen drink dispensers. An example is R. T. Cornelius' U.S. Pat. No. 3,608,779. Here, one compressor provides a discrete refrigerant supply for a precooler and a second compressor does the finish cooling of the semi-frozen product. The beverage is cooled well below freezing so there are few problems of control accuracy and/or repeatability.

Split evaporator systems are well known in juice dispensers and a representative system is shown in J. R. McMillin's U.S. Pat. No. 3,898,861. In this type of system, the refrigerant from a single compressor is divided between a juice reservoir and a diluent water cooler. Each divided half of the split system tries to do the entire cooling of its constituent; i.e., concentrate or water, in one step. All of these systems suffer from occasional failure, be it freeze ups or concentrate spoilage.

The type of water refrigeration presently being used by the large retailers of beverages, specifically the fast food stores, is a very large, bulky and expensive ice bank unit that may freeze several hundred pounds of ice in its ice bank. These devices take an inordinate amount of volume within the store. The size of these devices approaches the size of a sub-compact car. These devices have long run times and use quite a bit of electricity.

There is a great need for a physically smaller, higher capacity beverage cooler that weighs less, costs less, and is more efficient and which uses less electricity per unit of produced cold beverage.

It is an object of the present invention to provide a new improved method of making and dispensing cold carbonated water or beverage with a high efficiency and high BTU output precool and a very accurate final cool with both coolings, being done with refrigerant from a slngle source.

It is an object of the present invention to provide a new improved high efficiency method of making, cooling and dispensing a flow of cold carbonated water or beverage at a temperature just above freezing, with a high capacity and high thermal efficiency precool, and lower capacity but very accurate final cool with both coolings, being discretely done with refrigerant from a common source.

It is an object of the present invention to provide a new improved apparatus for making and dispensing cold carbonated water or beverage with a common source of refrigerant supplying both a high capacity and high thermal efficiency precooler, and a discrete ice bank type final cooler.

It is an object of the present invention to provide a new improved and highly efficient apparatus for cooling and dispensing cold carbonated water or beverage at just above freezing with a discrete high thermal efficiency precooler and a discrete thermally accurate final cooler, both of which are supplied refrigerant from a common source.

A method of making, cooling, and dispensing cold carbonated water or beverage has the steps of providing a supply of water, providing a single supply of condensed refrigerant gas, discretely precooling the water in a first heat exchanger, routing a first portion of refrigerant over the first heat exchanger, transferring the precooled water to a discrete second heat exchanger of the ice bank type, discretely first cooling the water in the ice bank exchanger, routing a second portion of refrigerant through the ice bank, carbonating the water, dispensing the water after the final cooling, discretely controlling the refrigerant portions, and condensing refrigerant if needed by either heat exchanger.

A high efficiency method of cooling and dispensing cold carbonated water at a temperature just as close as possible to freezing has the steps of providing a warm water supply, providing a single source of condensed refrigerant, discretely precoollng the water to the range of 35-50 degrees F. (1-10 degrees C.), discretely routing a portion of the refrigerant into a first exchanger for the precooling, transferring precooled water to a discrete second heat exchanger, discretely routing a second portion of refrigerant to the second heat exchanger which is of the ice bank type, discretely final cooling the water down to just above freezing, and thereby providing cold water at just above freezing.

Apparatus for making, cooling, and dispensing cold carbonated water, has a refrigeration high side, a water conduit, first discrete precooling structure for precooling the water, second discrete final cooling structure of the ice bank type and downstream of the precool structure for final cooling of the water, a carbonator spaced upstream of the final cooler first refrigerant discharge branch refrigerant valve structure for the first cooler structure, a second refrigerant discharge branch with discrete refrigerant valve structure for the second cooler structure, and a control for starting and running the compressor when either cooling structure needs refrigerant.

Apparatus for making, cooling and dispensing cold carbonated water or beverage at a temperature just above freezing has a refrigerant high side, a water conduit, a discrete precooler, a discrete final cooler of the ice bank type, a first refrigerant discharge branch with a discrete refrigerant valve for the precooler, a second refrigerant discharge branch with a discrete refrigerant valve for the final cooler, discrete controls for the precooler and the final cooler, and a control to run the compressor if in the precooler or the final cooler needs refrigerant.

A post-mix carbonated beverage dispensing apparatus with an improved refrigeration system for supply of common refrigerant to two discrete heat exchangers has a precool heat exchanger for cooling water down only to an intermediate moderate temperature, a discrete ice bank type heat exchanger, a water conduit having an inlet connectible to a source and an outlet connectible to one or more dispensing valves, the water conduit extends sequentially firstly through the precool and then through a water bath of the ice bank heat exchanger, a carbonator in the water conduit upstream of the ice bank heat exchanger, and a syrup conduit extending from a source and through the ice bank heat exchanger to the dispensing valve, the carbonated water of intermediate temperature is reliably and accurately final cooled to very close to freezing by the ice bank heat exchanger.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and accompanying drawings in which the preferred embodiment incorporating the principles of the present invention is set forth and shown by way of illustrative example.

FIG. 1 is a schematic drawing of the water cooling and refrigeration system of the present invention; and

FIG. 2 is a similar schematic drawing of the preferred embodiment of the beverage dispenser of the present invention.

According to the principles of the present invention, a dispensing apparatus for making, cooling and dispensing carbonated water is schematically shown in the drawing and is generally indicated by the numeral 10. The cooling apparatus has a refrigeration high side 12, a discrete first cooler which is hereafter referred to as the precooler 14, a discrete second cooler which is hereafter referred to as the final cooler 16, and a water conduit 18 extending sequentially through the spaced apart and discrete coolers 14, 16.

The refrigeration high side 12 is a conventional electromechanical refrigeration chassis with a compressor 20, a condenser coil 22, a condenser fan 24, a suction line 26, and a discharge line 28. The high side 12 may be alongside the coolers 14, 165 in a single structure, or the high side 12 may be a remote unit of the rooftop or behind and outside of the building types.

The water conduit 18 has an inlet end 30 adapted to be connected to a bulk supply of water, such as a municipal supply or private well, and to a water pressure booster pump 32. The water conduit 18 extends from the inlet 30 to an outlet 34 which is connectlble to at least one and usually more dispensing valve 36. The water conduit 18 extends firstly through an elongate length of heat exchanger tube 38 in the precooler 14, and then through a final cool coil 40 in the final cooler 16. The water conduit 18 extends through a carbonator 42 which is upstream of the final cooler 16, and in some cases downstream of the precooler 14, or in between the coolers 14, 16.

The precooler 14 is of a high capacity, extremely high efficiency type wherein the refrigerant gas is directly exposed to and placed in direct physical contact with the heat exchanger tube 38 of the water conduit 18. The precooler 14 has a tube-in-tube heat exchanger 44 wherein an elongate outer refrigerant tube 46 surrounds the water heat exchanger tube 38 and provides an elongate annular space 48 for precool refrigerant along the length of the heat exchange tube 38. The water heat exchanger tube 38 is preferably a helically twisted stainless steel tube with behind ribs that cause extremely high thermal contact and transfer. A first refrigerant discharge branch 50 extends from receiver 52 in the discharge line 28. The first branch 50 has a normally closed (NC) solenoid operated refrigerant supply valve 54, and a first thermal expansion refrigerant control valve 56 downstream of the supply valve 54. The heat exchanger 44 has a T-shaped precooler water inlet 58 as is shown and a thermal transducer well in the precooler water inlet 58. The water temperature transducer 60 extends into the water heat exchanger tube 38 and within the refrigerant tube 46. The transducer 60 is operatively connected to open and close the first refrigerant supply valve 54. A suction line temperature transducer 62 is on a discrete suction refrigerant outlet 64 from the precooler 14. The suction transducer 62 is operatively connected to open and close the refrigerant expansion valve 56 in response to the temperature of the refrigerant outlet 64.

A second discrete refrigerant branch 66 is connected to the discharge line 28 in parallel with the first branch 50. The second branch 66 connects the discharge line 28 to an evaporator coil 68 for freezing an ice bank 70 in the final cooler 16, which is an ice bank type cooler having a reservoir 72 filled with ice water which is circulated by an agitator motor 74. The second branch 66 has a discrete second normally closed (NC) refrigerant supply valve 76. An ice bank control 80 in the final cooler 16 determines if the ice bank 70 is of sufficient size or is too small. The ice bank control 80 is operatively connected to open and close the second branch refrigerant supply valve 76 in response to the size of the ice bank 70. A refrigerant temperature transducer 82 is on a discrete refrigerant outlet 84 from the ice bank coil 68. The transducer 82 is operatively connected to selectively open or close the second refrigerant control valve 78 in response to the temperature of the ice bank refrigerant outlet 84.

The carbonator 42 is supplied carbon dioxide gas at a regulated pressure from a gas bottle 86. A water level control 88 is operatively connected to turn the water pump 32 on and off to maintain a desired water level in the carbonator 32 under a propellant gas head of carbon dioxide gas in the carbonator 42.

The compressor 20 is provided with an on-off control 90 which is operatively connected to structure which will turn on the compressor 20 in response to either warm water in the precooler 14 or the size of the ice bank 70 in the final cooler 16.

A first structure for turning on the compressor 20 is a vacuum switch 92 in the suction line 26. If either of the supply valves 54, 76 is opened, refrigerant will be eventually sent into the suction line 26 and the rising refrigerant pressure will cause the vacuum switch 92 to turn on the compressor 20. When both supply valves 54, 76 are closed, a significant low pressure will be pulled in the suction line 28 and cause the vacuum switch 92 to turn off the compressor. The vacuum switch 92 will usually be used with a remote high side 12.

A second structure for turning the compressor 20 on and off is an optional control lead 94 which connects the water temperature transducer and the ice bank control 80 to an OR logic element 96 and thence to the compressor control 90. This type of control lead 94 will usually be used with an integral construction of the high side 12 and coolers 14, 16 as a single unit. If either the incoming water temperature transducer 60 calls for or requests refrigeration, or the ice bank control 68 calls for or requests refrigeration, the compressor 20 will be turned on simultaneously with the opening of either refrigerant supply valve 54, 76.

In the use and operation of the apparatus 10, and in the practice of the method of the present invention, warm water to be cooled and carbonated is provided via the inlet 30 to the water conduit 18. Water flowing into the precooler 14 warms up the incoming water transducer 60 which in turn opens the first refrigerant supply valve 54. A discrete first portion of condensed refrigerant from the received 52 discretely flows through the open refrigerant control valve 56 and into the refrigerant tube 46 and directly upon and over and along the water precool heat exchanger tube 38. The temperature of the refrigerant outlet 64 will gradually decrease and as the temperature sensed by the refrigerant outlet transducer 62 reaches a predetermined low temperature, the control vale 56 will be modulated to control or portion the quantity of refrigerant passing through the precooler 14 as a function of the refrigerant temperature of the outlet 64. Precooled water flows out of the precooler 14 at an intermediate moderate temperature in the range of 35-50 degrees F. (1-10 degrees C.). The range of variation can quite easily be controlled closed, for example 40-45 degrees F. (4.5-7.2 degrees C.). Regardless, the water temperature is sufficiently high enough above freezing so that there is absolutely no probability of a freeze up in the precooler 14. The water is simply not cooled close to freezing in the precooler 14 so there is no probability of freeze-up and failure. The water is not cooled to the serving temperature in the precooler 14. The majority of the water cooling is done in the precooler 14 and the precooled water temperature is brought to a temperature that is only as low as the control envelope will allow; the water is not further cooled. The precooling is done with the refrigerant directly upon the water tube 38 at a high temperature differential and is of the highest efficiency and highest cooling rate possible with a given compressor 20. The precooled water is transferred into the carbonator 42 at about 45 degrees F. (7 degrees C.) and is completely carbonated in the carbonator 42 at about 50 PSIG carbonation pressure under a head of carbon dioxide gas which easily gives a nominal carbonation in excess of 5 volumes. The carbonated water is then subsequently transferred while under the pneumatic carbonation pressure from the carbonator 42 and into the final cooling coil 40 wherein the previously carbonated water is final cooled to as close to freezing or 32 degrees F. (0 degrees C.) as is physically possible. A minor portion of the cooling is done in the final cooler 16 and again there is no posslbility of freeze up because of the ice bank 70 and the ice water bath being used between the final cooler evaporator 68 and the final cooling water coil 40. All cooling of carbonated water in the final cooler 16 is done by melting of ice from the ice bank 70.

When the final cooler 16 has done a quantity of final cooling, the ice bank 70 will have been reduced in physical size and the ice bank control 80 will sense that the ice bank 70 is too small. The ice bank control 80 will open the refrigerant supply valve 76 and a second portion of condensed refrigerant will flow from the receiver 52 through the supply valve 76 and the control valve 78 and through the ice bank coil 68. The transducer 82 monitors the temperature of the final cooler refrigerant outlet 84 and modulates the control valve 78 accordingly to provide an optimal and portioned flow of refrigerant.

It has been explained that either the precooler 14 or the final cooler 16, can effect turn on of the compressor 20. Both the precooler 14 and the final cooler 16 can also concurrently call for a request refrigeration and both refrigerant supply valves 54, 76 can be concurrently opened. In this circumstance the refrigerant control valves 56, 78 portion out the refrigerant in order to produce the greatest possible cumulative cooling of water.

The carbonated water being dispensed out of the dispensing valve 36 is usually about 10-15 degrees F. (5-8 degrees C.) colder than when it is carbonated; it is always colder. The carbonation pressure and therefore the propellant pressure is higher than the carbonation saturation pressure at the outlet of the final cooler 16 and at dispensing valve 36. This phenomena enables the apparatus 10 to very effectively be placed in a basement or lower level and to propel carbonated water to a dispensing valve 36 located remotely or at a higher elevation. The apparatus 10 is ideally suited for very high volume beverage retailers where the dispensing vale 36 is on an upper level, the precooler 14 and final cooler 16 are in a lower level, and the high side 12 is on the roof or outside of the building. The apparatus 10 is particularly effective with high inlet water temperatures.

In the second and preferred embodiment of a post-mix beverage dispensing apparatus 10A illustrated in FIG. 2, like components are given like reference numerals. One of the major improvements is that the carbonator 442 is located upstream of the precooler 14. This enables more consistent carbonation to be obtained compared to the arrangement shown in FIG. 1 as the water inlet temperature is usually more even than the precooler 14 outlet temperature, which very much depends on the water throughput rate. Furthermore because the water is warmer, higher CO2 pressures are required to obtain the necessary levels of absorption and carbonation, and this increases the propellant pressure on the carbonated water in the apparatus 10A to enhance propulsion of water through the system and the beverage dispensing valves 36A, 36B.

A second major improvement is the location of the water transducer 60 on the outlet 59 to the precooler 14 rather than on the inlet 58. This prevents the refrigeration system from fast cycling on and off thus lengthening its life in service. It also slows down the reaction time of the precooler when water starts to flow.

A third major improvement is the OR logic switch 96 which is now prioritized, so that it normally sits in the position shown in the drawing. In this position valve 76 is open and valve 54 is closed. The ice bank 70 is built up under the control of the thermostat 80. However, if transducer 60 senses warm water the switch 96 is operated to cut off current to valve 76, which closes, and to electrify valve 54 which opens to exclusively direct all of the refrigerant to the precooler coil 46.

Fourthly, the beverage concentrate may be supplied from a source 100 through a cooling coil 101 in the water bath 72 before being supplied to one of respective beverage dispensing valves 36A, 36B.

In the improved apparatus 10A, the logic of the prioritized OR switch 96 gives exclusive priority to all of the refrigerant to the precooler 14. The switch 96 is operative to shift all of the refrigerant to the precooler 14 during dispensing and while the compressor 20 is running without shut off of the compressor 20 and without any loss of compressor capacity. During freezing of the ice bank 70, the effective BTU output of the compressor 20 is about 7000 BTU/hour. During water flow through the precooler, heat extraction of up to 27,000 BTU has been measured with the same compressor 20. The BTU extraction increases with water flow rate and/or water inlet temperature. All syrup cooling is done in the final cooler 16.

This apparatus 10, 10A and method are extremely effective. Initial testing indicates that this apparatus 10, 10A and method will provide as much cold carbonated water and/or beverage as currently used units of four times the size of the apparatus 10. More specifically, this apparatus 10, 10A and method with a 50 pound ice bank 70 will provide more cold carbonated water and/or beverage than a 200 pound currently used ice bank unit of current state of the art construction. The apparatus 10, 10A and method of this invention are extremely useful in retailing environments wherein the dispensing may be done on any one or all of random draw during off times or slack business hours, heavy repetitive draw cycles during lunch, dinner and other peak business times, or continuous flow for production of gallonage of carbonated water. The apparatus 10, 10A absolutely excels with the high flow rates and high water temperatures found in the Southern U.S.A. during summer.

Although other advantages may be found and realized and various modifications may be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of my contribution to the art.