Temperature-controlled beverage dispenser

Abstract

A temperature-controlled beverage dispenser is disclosed, which provides a cold plate having disposed therein beverage lines and refrigerant lines. The refrigerant lines may be connected to a cooling system, such as a heat exchanger, which is configured to remove heat from the cold plate. The beverage lines may be connected to a beverage supply for dispensing a desired beverage. Valves and a pressure sensor in the refrigerant line are connected to a microprocessor. At regular intervals, the microprocessor closes the valves, waits a short time, and then takes a pressure reading, which corresponds to a temperature. If the temperature falls below a desired value, then the cooling system is shut off. This permits the microprocessor to closely control the temperature of the beverage being dispensed.

Claims

1. A system for controlling temperature of a beverage that is cooled by a cooling system having a compressor, a condenser, a heat-conductive cold plate, and an accumulator, the system comprising: a liquid line valve fluidly positioned downstream of the condenser and upstream of the cold plate; an evaporator valve fluidly positioned downstream of the cold plate and upstream of the accumulator; a temperature or pressure measuring device configured to detect temperature or pressure, respectively, of the refrigerant disposed between the liquid line valve and evaporator valves, a processor configured to control operation of the compressor and the liquid line and evaporator valves as a function of data received from the measuring device; a memory communicatively coupled to the processor, and containing instructions that when executed instruct the processor to: i) close both the liquid line and the evaporator valves, ii) following a stabilizing period of time, and while both the liquid line and the evaporator valves are closed detect a then-current refrigerant pressure or temperature, and then ii) either (a) open both the liquid line and evaporator valves, and run the compressor if the detected refrigerant pressure or temperature is at or above a high threshold value, or (b) de-energize the compressor if the detected refrigerant pressure or temperature is at or below a low threshold value; wherein the steps i) through ii) are executed periodically while the detected temperature or pressure is/are within an intermediate range between the high threshold value and the low threshold value.

2. The system of claim 1, wherein the low threshold value is between 60 psi and 70 psi, inclusive.

3. The system of claim 1, further comprising: a beverage conduit cooled by the cold plate; and a tap disposed to deliver the beverage after the beverage passes through the beverage conduit.

4. The system of claim 1, further comprising the instructions, when executed, instruct the processor to run the compressor during the stabilizing period of time.

5. The system of claim 1, wherein the high threshold value is between 65 psi and 81 psi.

6. The system of claim 1, wherein the low threshold value is between 62.5 psi and 78.5 psi.

7. The system of claim 1, wherein the high threshold value is between 27.1 F. and 37.5 F.

8. The system of claim 1, wherein the low threshold value is between 25.5 F. and 35.9 F.

Description

(1) FIG. 1 is a perspective view of the tabletop unit showing the housing, the beverage outlets, and the spill tray.

(2) FIG. 2 is an equipment layout, not to scale, showing the relative positions of the elements of Applicants' novel beer cooling system.

(3) FIG. 2A is a block diagram illustrating the microprocessor inputs and outputs.

(4) FIGS. 3 and 4 are perspective views of the equipment layout showing the elements of the cooling system in place with the housing cover removed therefrom.

(5) FIG. 5 is an elevational view of the beverage or beer lines and refrigeration lines within the cold plate.

(6) FIG. 6 is a perspective view of a layout for use with Applicants' novel beverage cooling system which shows a tabletop supporting the unit, which tabletop in turn is supported by legs or a cart or the like; the product here, two different beverages, are provided in feed lines to the rear of the housing of the unit.

(7) FIG. 7 is a perspective view of the cold plate showing refrigeration lines and beer lines laying adjacent one another and embedded within an aluminum casting.

(8) FIG. 8 is a flow chart illustrating the standby mode.

(9) FIG. 9 is a flow chart illustrating the compressor mode.

(10) FIG. 10 is a flow chart illustrating the pump down mode.

(11) Run solenoids 34/40 are on (valves opened) and defrost solenoid 42 is on (valve open). Compressor 28 is on and fan 29 is off. Defrost mode runs for a period of T3, for example, for 40 seconds then standby mode is entered. Defrost mode cannot be reentered until a compressor mode cycle has completed.

(12) TABLE-US-00001 TABLE 1 Setpoints On Off Temp On Te Tp Off 1 65 62.5 27.1 25.5 2 67 64.5 28.4 26.8 3 69 66.5 29.7 28.1 4 71 68.5 31.0 29.4 5 73 70.5 32.3 30.7 6 75 72.5 33.6 32.0 7 77 74.5 34.9 33.3 8 79 76.5 36.2 34.6 9 81 78.5 37.5 35.9

(13) TABLE-US-00002 TABLE 2 Temperature Pressure LOW 28 68 HIGH 36 78 Diff 8 12 Pressure Diff per degree 1.53

(14) T1 (see FIG. 8) is a period of time in which the system is in a standby mode which was entered after the cold plate was sufficiently cold and the low end PT1 pressure was below a preset minimum, for example, 10 psi. The system, left in the standby mode, would typically warm up, for example, towards room temperature or when a beer is drawn from adding heat to the cold plate. Thus in standby mode, the cold plate is being monitored for a period of time T1. This period should be short enough to be responsive to temperature change at the cold plate, for example, drawing a beer. It should not be too short generating unnecessary monitoring.

(15) Time period T2 is a time period between leaving standby mode, when the on set point is exceeded and entering compressor mode. That is, time period T2 should not be too long, as the system needs heat removed therefrom.

(16) In compressor mode, the microprocessor (monitor) is looking at the cold plate temperature and comparing it to a pre-selected temperature of either 60 psi or the compressor off temperature 8 psi or an appropriate value below the off set point. It has been determined, through experimentation, that a more accurate reading of the cold plate occurs if run valves 34/40 are closed for a period of time, for example, T3, here 1.5 seconds, after which period of time the cold plate is monitored. If, in the compressor mode, the closed valve reading is below the off set point, here, for example, 68.5, then the system will enter the pump down mode. If the closed valve reading is greater than the off set point, the valves will open and the time period, for example, T4 will be applied and then the cold plate pressure will again be checked. For a time period, T3 experimentation can determine as short a time as possible for pressure in the cold plate to stabilize. For a period of time T4 is not too long or the off set point here, for example, 68.5, may be overshot. If T4 is too short, you are hurting your cooling capacity by having the valves closed again for T3.

(17) While the subject of this specification has been described in connection with one or more exemplary embodiments, it is not intended to limit the claims to the particular forms set forth. On the contrary, the appended claims are intended to cover such alternatives, modifications and equivalents as may be included within their spirit and scope.