Cooling System With Multiple Evaporators

Abstract

A cooling system for a refrigerator and a water cooler. A cabinet is provided with a refrigeration chamber having a first evaporator contained therein and a water cooler chamber having a second evaporator contained therein. The evaporators are connected to a single condenser and to first and second valves. The condenser and evaporators are further connected to a compressor. A control circuit is further provided for controlling the valves. The valves remain open while the compressor is off allowing the fluid pressure to equalize on either side of the compressor.

Description

BACKGROUND OF THE INVENTION

This invention relates to an improved multiple evaporator cooling system. More particularly, it relates to an improved refrigerator-water cooler having a pair of evaporators, a compressor and a control circuit where the pressure on the opposite sides of the compressor are nearly equal before the starting of the compressor and the evaporators operate independently of one another.

Refrigeration systems have been provided utilizing a single condenser to operate a pair of evaporators. Usually two evaporators are used in order to provide two enclosures at two different temperatures. The most evaporator double evaorator system is probably the refrigerator-freezer. Another system utilizing two evaporators is a single cabinet having refrigerator chamber and water cooler chamber whereby the water-cooler chamber is cooled by a first evaporator and the refrigerator chamber by a second evaporator. Each chamber utilizes its own thermostat which respond independently to different temperatures. The thermostats are respectively connected to a pair of valve coils. These valve coils operate a pair of valves which connect each evaporator to the condenser which is in the refrigerator system and the water cooler system. When a valve is opened refrigerant fluid is allowed to flow from the condenser to the evaporator. There is also included a pressure switch which is connected to the evaporator side of the compressor and is responsive to a predetermined pressure from the evaporators. The pressure switch is closed thereby turning on the compressor when this pressure builds to the predetermined valve. This pressure build-up is caused when the formerly closed valves are opened thereby allowing fluid to flow into the evaporators. Furthermore, there is a capillary tube connected between each refrigerant valve and each evaporator. Each capillary tube is a very thin tube which regulates the amount of fluid flowing into the evaporators. Because of the smallness in diameter of these capillary tubes, it often takes a large amount of time for the refrigerant fluid to flow from the condenser into each evaporator. This time lag occurs between the time the thermostats indicate that it is time for cooling and the time that the compressor actually comes on, as determined by the pressure switch. This can cause obvious problems in that the compartment may become to warm thereby damaging the goods if the time delay is too long. Furthermore, in the system as described above, utilizing a pressure switch, the compressor must start against a high differential pressure. There will be a substantial pressure differential across the compressor during starting. This is a disadvantage because the starting torque of the compressor motor may not be high enough to start the motor without tripping the motor overload protector. An even further delay is introduced waiting for the motor protector to reset.

There are also other dual evaporator systems which use two compressors but they really have separate systems. Other dual evaporator systems are of a type which supply fluid to either one evaporator or another but not both at the same time. One side dominates over the other and the valves were dependent upon one another.

SUMMARY OF THE INVENTION

Accordingly, it is the general object of the invention to provide a cooling system utilizing a compressor having substantially equal fluid pressure on either side before starting.

Another object is to provide a multiple evaporator cooling system having a single compressor which comes on and off independently of the pressure.

Another object is to provide a multiple evaporator cooling system having multiple valves for controlling fluid in the system, the valves being opened by an electrical control circuit while the compressor is off.

In accordance with one form of the invention there is provided a refrigerator-water cooler including an enclosure divided into a refrigerator compartment and a water cooler compartment. A first evaporator is included in the refrigerator compartment and a second evaporator is included in a water cooler compartment. A compressor is connected on one side of the first and second evaporators. A pair of valves, operating independently, are connected between the evaporators and condenser for controlling fluid flow therebetween. A control circuit is further provided for operating the compressor and for opening and closing the valves. The control circuit includes a means for keeping the valves open at all times while the compressor is not running thus equalizing the pressure across the compressor whereby the compressor will start against substantially zero pressure load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of the front perspective view of a refrigerator-water cooler enclosure showing parts of the cooling system and the control circuit.

FIG. 2 is a diagram of the rear perspective view of the refrigerator-water cooler showing parts of the cooling system and the control circuit.

FIG. 3 is a schematic diagram of the cooling system and the control circuit used in FIGS. 1 and 2.

Description of the Preferred Embodiment

Referring now more particularly to FIG. 1 there is shown a refrigerator-water cooler having two cooling chambers. Chamber 1 is a refrigerator chamber having a refrigerator evaporator 3 attached to ice tray container 17. The water cooler compartment 2 includes cold water chamber 11 with water cooler evaporator 10 connected around it. The cold water chamber is supplied with water from reservoir 12 which is connected to the refrigerator box at opening 13. Cold water is released from water tap 16.

The cooling system may be better understood by referring to FIG. 2 which shows the backside of the refrigerator-water cooler with the sides and top removed. Refrigerator evaporator 3 is connected on one side to compressor 6 and on the other side to capillary tube 4. Capillary tube 4 is relatively narrow in diameter. Capillary tube 4 is further connected to electromechanical valve 5. This valve controls the flow of refrigerant fluid to evaporator 3. Cold water evaporator 10 is connected to compressor 6 together with refrigerator evaporator 3 through tube 19. The other side of water cooler evaporator 10 is connected to capillary tube 9. Capillary tube 9 is also narrow in diameter and is further connected to electro-mechanical valve 8. This valve controls the flow of fluid from the mechanical condenser 7 to refrigerator evaporator 10. Control circuit 14, shown in block form, is used to control the current through valve coils 29 and 31 and further to control the starting and stopping of compressor 6. Valve coils 29 and 31 are used to control the opening and closing of valves 5 and 8 respectively which operate independently of one another.

FIG. 3 shows a detailed schematic circuit diagram of control circuit 14 together with a schematic diagram of the cooling system. An operating potential is connected across input terminals 24 and 25. Compressor 6 is connected to the input terminal 24 through thermostat switches 34 and 35. The opening and closing of thermostats switches 34 and 35 are controlled by thermostats 32 and 33 respectively. A thermostat and a switch may be one unit or may be separated. Switch 34 will close when the temperature sensed by thermostat 32 reaches a predetermined value. Switch 35 will close when the temperature sensed by thermostat 33 reaches another predetermined value. Thermostat 32 is located in the water cooler chamber 2 and thermostat 33 is located in refrigerator container 1. When either switch 34 or 35 or both switches are closed this completes the compressor circuit and the compressor comes on. Switch 34 is electrically connected to the series branch including switch 38 and relay coil 39. Relay coil 39 is further connected to input 25. Switches 34 and 35 are respectively mechanically gauged to switches 38 and 36 in such a manner that when switch 34 is open switch 38 is closed and when switch 35 is open switch 36 is closed and vice-versa. Switches 34 and 38 are complimentary and switches 35 and 36 are complimentary. Switch 35 is electrically connected to switch 36 and to one side of relay coil 37. The other side of relay coil 37 is further connected to input terminal 25. Relay coil 37 is magnetically coupled to relay switch 28 so that when current flows through coil 37 switch 28 is open. Relay coil 39 is magnetically coupled to relay switch 30 to form a relay. When current flows through coil 39, switch 30 is open. Relay switch 30 is connected in series to valve coil 31 and this is connected across input terminals 24 and 25.

Valve coil 31 is magnetically connected to water cooler valve 8 such that valve 8 is open when current flows through valve coil 31. Switch 30 is normally closed, that is, while the compressor is not running current flows through valve coil 31 causing valve 8 to remain open. Since valve 8 tends to remain open pressure will tend to equalize on either side of the compressor while it is not running.

Relay switch 28 is connected to valve coil 29. This series relationship is also connected across input voltage terminals 24 and 25. Valve coil 29 is magnetically coupled to valve 5 to control the valve. FIG. 3 shows the valves and valve coils separated but they may be parts of one unit as shown in FIG. 2. Current also flows through valve coil 29 while the compressor is not running and thus valve 5 is also normally open while the compressor is not running further equalizing pressure across the compressor. Furthermore, since pressure switch is not used to start the compressor, there is no time delay for pressure buildup through capillary tubes 4 and 9 in order to close a pressure switch.

In operation, input operating potential is applied across terminals 24 and 25. While the temperatures inside the refrigerator chamber and the water cooler chamber are cool enough such that thermostats 32 and 33 are not actuated, current flows from input terminal 24 through normally closed switch 28 and valve coil 29 and through normally closed switch 30 and valve coil 31. Thermostat switches 34 and 35 are open and the compressor 6 is off. The two valve coils 29 and 31 are electro-magnetically coupled to valves 5 and 8 and cause these two valves to remain open. Fluid pressure around the fluid circuit is thus equalized while the compressor 6 is not operating, i.e., the pressure in tubes 18 and 19 are approximately equal. Thus, when compressor 6 comes on, it will not have to start against a pressure load since the pressure on either side of it is equalized.

When the temperature near thermostat 32 is high enough such that it activates switch 34 a current flows from terminal 24 through switch 34 and compressor 6 back to input terminal 25. This energizes the compressor motor with no time delay for fluid to flow through capillary tube 10. That is, as soon as thermostat 32 indicates that more cooling is needed the compressor begins to run. In the past, there was a pressure switch between input terminal 24 and compressor 6 and in that case the compressor would only come on when there was sufficient pressure on the evaporator side of the compressor to cause the pressure switch to close. The need for the pressure switch has been eliminated in this circuit.

As thermostat 32 closes switch 34, it also opens mechanically gauged switch 38. However, switch 36 remains closed and current flows from input terminal 24 through switch 34, through switch 36, and relay coil 37 back to input terminal 25. Relay coil 37 is electro-magnetically coupled to the relay switch 28. This current causes relay switch 28 to open thus stopping current flow through refrigerator valve coil 29 and further causes the refrigerator valve 5 to close. However, current continues to flow through switch 30 and water cooler valve coil 31 allowing water cooler valve 8 to continue to be open. Thus, the compressor forces fluid from the condenser 7 through valve 8, through capillary tube 9, and into the water cooler evaporator 10. This causes the temperature in water cooler evaporator 10 to lower and when it is sufficiently low, thermostat 32 will reopen switch 34 and stop the compressor. When switch 34 reopens this stops current flow through switch 36 and relay coil 37 which allows relay switch 28 to close. Current again flows through valve coil 29 allowing refrigerator valve 5 to again open, which allows the pressure again to equalize across the compressor 6.

When the temperature around thermostat 33, which is located in the refrigerator compartment 1, becomes high enough such that the thermostat causes switch 35 to close, switch 36 opens. This allows current to flow through switch 38 and relay coil 39 causing relay switch 30 to open. With relay coil 30 open no current flows through valve coil 31 thus valve 8 closes and no fluid flows to water cooler condenser 10. With current still flowing through switch 28 and valve coil 29, fluid flows through valve 5 from the compressor to the condenser and through capillary tube 4 and into refrigerator evaporator 3 thus lowering the temperature inside refrigerator compartment 1. It is further possible that both the refrigerator and water cooler chamber require refrigerant material at the same time. Under this condition both thermostats 33 and 32 cause switches 35 and 34 to close. This completes the compressor circuit and opens both switches 36 and 38. Switches 36 and 38 are open while 28 and 30 are closed allowing current to flow through valve coils 29 and 31. This keeps valves 5 and 8 open allowing refrigerant material to flow into both refrigerator evaporator 3 and water cooler evaporator 10. Thus, it is possible for both the water cooler chamber and the refrigerator chamber to receive a coolant fluid without one system dominating over the other one.

From the foregoing description of the embodiment of the invention it will be apparent that many modifications may be made therein. It will be understood, however, that this embodiment of the invention is intended as an exemplification of the invention only and the invention is not limited thereto. It will be understood, therefore, that it is intended in the appended claims to cover all modifications as fall within the true spirit and scope of the invention.

Claims

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigeration system and a control circuit comprising: input means for connecting the circuit to a source of operating potential; first and second thermostats; a first switch responsive to said first thermostat connected to said input means; a second switch responsive to said second thermostat connected to said input means; a compressor connected to said first and second switches, said compressor being energized upon the closing of any of said first and second switches; a third switch connected to a first relay coil; a fourth switch connected to a second relay coil; said third and fourth switches being electrically connected to said first and second switches, said third switch being mechanically ganged to said first switch so that when said first switch is open said third switch is closed and visa versa, said fourth switch being mechanically ganged to said second switch so that when said second switch is open said fourth switch is closed and visa versa; a first relay switch connected to a first valve coil and to said input means, said first relay switch being coupled to said first relay coil, said first relay switch being opened upon energization of said first relay coil; a second relay switch connected to a second valve coil and to said input means, said second relay switch being coupled to said second relay coil, said second relay switch being opened upon energization of said second relay coil; first and second electromechanical valves connected to a mechanical condensor, said first and second valves being opened during energization of said first and second valve coils respectively; said condensor being connected to said compressor; a first and second evaporator respectively connected to said first and second valves; said first and second evaporator being connected to said compressor.

2. A refrigerator-water cooler comprising: an enclosure divided into a refrigerator compartment and a water cooler compartment; a cooling system adapted to receive a coolant including: a first evaporator included in said refrigerator compartment, a second evaporator included in said water cooler compartment, a compressor connected to one side of said first and second evaporators, first and second valves connected respectively to the other sides of said first and second evaporators, said first and second valves being open at least while said compressor is off, a condenser connected between said compressor and said valves; a control circuit for controlling the operation of said compressor and the operation of said first and second valves including a first coil magnetically coupled to said first valve for controlling said first valve, a first relay switch connected to said first coil for controlling the current through said first coil, a second coil magnetically coupled to said second valve for controlling said second valve, a second relay switch connected to said second coil for controlling the current through said second coil, whereby the coolant pressure on both sides of said compressor is approximately equal while said compressor is off.

3. A cooling system and control circuit comprising: first and second enclosed compartments; first and second evaporators respectively included in said first and second compartments for absorbing heat; first and second thermostats respectively included in said first and second compartments for sensing temperature; input means for connecting the control circuit to a source of operating potential; first and second switches connected to said input means and controlled respectively by said first and second thermostats; a compressor connected to said first and second switches; said compressor connected to a cooling system including said first and second evaporators, first and second valves respectively connected to said first and second evaporators for controlling cooling fluid flow; means for opening and closing said first and second valves in response to said first and second thermostats whereby said valves remain open at least while said compressor is off.

4. A cooling system and control circuit as set forth in claim 3 wherein said first and said second valves operate independently of one another.

5. A cooling system and control circuit as set forth in claim 3 wherein said first and second switches are connected in parallel; third and fourth switches connected to said first and second switches, said third and fourth switch being respectively complimentary to said first and second switches; first and second relays respectively connected to said third and fourth switches and further connected to said input means; first and second valve coils respectively connected to said first and second relays and further respectively coupled to said first and second valves for controlling the fluid flow through said valves.