Alternate path for refrigerant flow on a split system icemaker

Abstract

An ice-making machine and method that uses an accumulator to accumulate liquefied refrigerant when warm gasified refrigerant is supplied to the evaporator after a freeze cycle. During a harvest cycle, a set of valves operates to bypass the condenser and direct the discharged gasified refrigerant from the compressor through the accumulator and then to the evaporator. The warm gasified refrigerant converts the liquefied refrigerant to gaseous refrigerant. This enhances the suction pressure to the compressor during the next ensuing freeze cycle, thereby increasing the efficiency of the accumulator.

Description

RELATED APPLICATION

[0001] This Application claims the benefit of U.S. Provisional Application No. 60/261,449, filed Jan. 12, 2001.

FIELD OF THE INVENTION

[0002] This invention relates to a method and system that converts liquid refrigerant to a gas after a freeze cycle in an ice-making machine.

BACKGROUND OF THE INVENTION

[0003] Ice-making machines generally include an evaporator, a refrigerant supply, a water supply and an ice bin. During a freeze cycle, the evaporator is cooled by liquid refrigerant provided by the refrigerant supply so as to form ice cubes from water provided by the water supply. During a subsequent harvest cycle, the evaporator is warmed by hot gas that is provided by the refrigerant supply to free the ice cubes, which then fall into the ice bin. The refrigerant supply includes a compressor, a condenser and valving connected in a refrigerant circuit with the evaporator. During the harvest cycle, the valving connects the compressor and evaporator via a bypass circuit that bypasses the condenser so as to supply the refrigerant in a gaseous state to warm the evaporator.

[0004] As the freeze cycle ends and the harvest cycle begins, the liquefied refrigerant is partially warmed by the hot gas, but is still partly liquid as it is forced by the hot gas out of the evaporator to the compressor. This results in the compressor trying to compress the liquefied refrigerant, which is a task that it is not designed to handle. U.S. Pat. No. 5,105,632 describes one solution to this problem that involves the insertion of a pump down cycle between the freeze cycle and the harvest cycle. During the pump down cycle, the hot gas is circulated through the compressor and evaporator for a time sufficient to vaporize the refrigerant.

[0005] Another solution to the aforementioned problem is to provide an accumulator between the evaporator and the compressor. The accumulator collects any liquefied refrigerant and passes only vaporized refrigerant onto the compressor. The accumulator is constructed to have a dip tube that includes a sized orifice, which serves as an oil return to the compressor. In a split system, in which a considerable distance separates the evaporator and the compressor, it is possible for larger amounts of refrigerant to be directed to the compressor during the harvest cycle. To accommodate the additional volume, the orifice is increased in size.

[0006] Liquid refrigerant contained in the accumulator must be converted to gas. During the harvest cycle, hot refrigerant gas flowing into the evaporator continues on to the accumulator. However, the amount of heat contained in the refrigerant gas during the harvest cycle is insufficient to convert the liquid refrigerant in the accumulator to gas. Moreover, the harvest cycle has a short duration that has two negative effects. First, the heat removal ability of the compressor is greatly reduced during the beginning of the ensuing freeze cycle. This extends the freeze cycle, thereby reducing the daily production capacity of the ice-making machine. Second, liquid return to the compressor can be harmful over longer periods of time.

[0007] There is a need to overcome the problem of converting liquid refrigerant to gaseous refrigerant during a harvest cycle.

SUMMARY OF THE INVENTION

[0008] The method of the present invention supplies liquefied refrigerant to an evaporator during a freeze cycle and accumulates liquefied refrigerant during a subsequent cycle. Gasified refrigerant is supplied to the accumulator and to the evaporator during the subsequent cycle so as to warm the accumulated refrigerant and thereby assist in its conversion to a gaseous state and satisfy the aforementioned need.

[0009] The ice-making machine of the present invention includes an evaporator, an accumulator, a compressor, a bypass line and a condenser connected in a circuit to supply liquefied refrigerant to the evaporator during a freeze cycle and gasified refrigerant to the evaporator during a subsequent cycle. The bypass line passes through the accumulator, which accumulates liquefied refrigerant during the subsequent cycle. A valve means connects the bypass line in the circuit during the subsequent cycle so that the gasified refrigerant bypasses the condenser and passes through the accumulator to thereby warm the accumulated liquefied refrigerant and assist in converting it to a gaseous state.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and:

[0011] FIG. 1 is a block diagram of an ice-making machine of the present invention; and

[0012] FIG. 2 is a schematic diagram of the refrigerant supply of the ice-making machine of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Referring to FIG. 1, an ice-making machine 20 includes an evaporator 22, a water supply 24, a refrigerant supply 26, an ice bin 28 and a controller 30. Controller 30 controls water supply 24 and refrigerant supply 26 to produce ice forms, such as cubes or other shapes, during a freeze cycle, to harvest the ice forms during a harvest cycle as well as during other cycles used in ice making machinery. Thus, refrigerant supply 26 supplies liquid refrigerant to cool evaporator 22 during a freeze cycle. Water supply provides water to the cooled evaporator so as to produce the ice forms. During the harvest cycle, the refrigerant supply 26 supplies a gasified refrigerant that warms evaporator 22, thereby freeing the ice forms, which fall into ice bin 28.

[0014] Referring to FIG. 2, refrigerant supply 26 is shown for a split system that has an evaporator package 32, a compressor package 60 and a condenser package 80. Evaporator package 32 may be located in a room of a building where the ice making takes place. The compressor package 60 and the condenser package 80 are located a considerable distance from the evaporator package 32 to shield users from the noise of the compressor and condenser. The compressor package 60 and the condenser package 80 may be located in the same location or in different locations. For example, evaporator package 32 may be located in a first floor room and compressor package 60 and condenser package 80 may be located on the roof. Alternatively, compressor package 60 may be located in a separate room and condenser package 80 may be on the roof.

[0015] Evaporator package 32 includes evaporator 22 that is connected in a circuit 52 with a receiver 34, a drier 36, an expansion valve 38, a solenoid valve 40, a defrost valve 42, a check valve 44 and hand valves 46, 48 and 50. Hand valves 46 and 48, when open, connect circuit 52 to compressor package 60 via supply line 54 and return line 56. Compressor package 60 includes compressor 62, accumulator 64 and filter 68 that are connected in series to return line 56. Bypass line 70 has portion 78 that is situated in accumulator 64. Valve arrangement 72 has a normally open valve 74 and a normally closed valve 76. During the freeze cycle, controller 30 operates valve 76 to its normally closed position and valve 74 to its normally open position so that condenser package 80 is connected between supply line 54 and a discharge output line 79 from compressor 62. During a subsequent cycle, controller 30 directs valve 74 to close and directs valve 78 to open, so that bypass line 70 connects discharge output line 79 of compressor 62 to supply line 54, thereby bypassing condenser package 80.

[0016] Condenser package 80 includes a condenser 82 and a condenser fan 84. Condenser 82 is connected across supply line 54 and the output of valve 74.

[0017] During freeze cycles, controller 30 opens valve 74 and closes valve 76 and operates compressor 62 and condenser 82 to provide cool liquid refrigerant through supply line 54 to evaporator package 32 and evaporator 22. During a cycle occurring after a freeze cycle, e.g., a harvest cycle, controller 30 closes valve 74 and opens valve 76. This connects bypass line 70 between discharge output line 79 of compressor 62 and supply line 54. Controller 30 operates compressor 62 to supply warm gasified refrigerant via bypass line 70 and supply line 54 to evaporator 22. Liquefied refrigerant still in evaporator 22 is forced out and accumulated in accumulator 64. Gasified refrigerant above the liquid level is transferred via a dip tube 66 to compressor 62. The warm gasified refrigerant flowing through portion 78 of bypass line 70 warms the accumulated liquefied refrigerant in accumulator 62, thereby assisting in its conversion to gasified refrigerant. The conversion of the accumulated liquefied refrigerant to a gaseous state during a harvest cycle increases the suction pressure in return line 56 during the initial part of the ensuing freeze cycle, thereby increasing the efficiency of accumulator 64.

[0018] The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. An ice-making machine comprising:

an evaporator, an accumulator, a compressor and a condenser connected in a circuit for the supply of liquefied refrigerant to said evaporator during a freeze cycle and of gasified refrigerant to said evaporator during a subsequent cycle, wherein said accumulator accumulates liquid refrigerant during said subsequent cycle;

a bypass line that passes through said accumulator; and

a valve means that connects said bypass line in said circuit during said subsequent cycle so that said gasified refrigerant bypasses said condenser and passes through said accumulator to thereby convert at least a portion of said accumulated liquefied refrigerant to a gaseous state.

2. The ice-making machine of claim 1, wherein said accumulator is disposed between said evaporator and said compressor.

3. The ice-making machine of claim 1, wherein said valve means disconnects said bypass line before another freeze cycle starts.

4. The ice-making machine of claim 1, wherein said subsequent cycle is a harvest cycle in which ice formed on said evaporator during said freeze cycle is harvested.

5. The ice making machine of claim 3, further comprising a controller that controls the operation of said valve means.

6. A method of making ice comprising:

a) supplying a liquefied refrigerant to an evaporator during a freeze cycle;

b) accumulating liquefied refrigerant during a subsequent cycle; and

c) supplying gasified refrigerant to said evaporator during said subsequent cycle in a manner whereby said accumulated liquefied refrigerant is converted to a gaseous state.

7. The method of claim 6, wherein said subsequent cycle is a harvest cycle in which ice formed on said evaporator during said freeze cycle is harvested.

8. The method of claim 6, wherein step b) accumulates liquefied refrigerant in an accumulator, and wherein step c) supplies said gasified refrigerant via a bypass line that passes through said accumulator.

9. An ice-making machine comprising:

an evaporator, an accumulator, a compressor and a condenser connected in a circuit for the supply of liquefied refrigerant to said evaporator during a freeze cycle and of gasified refrigerant to said evaporator during a subsequent cycle, wherein said evaporator is disposed in a first location and said accumulator, said compressor and said condenser are located remotely from said first location so that noise due to said compressor and said condenser is substantially reduced at said location, and wherein said accumulator accumulates an increased amount of liquid refrigerant during said subsequent cycle due to being located remotely from said location of said evaporator;

a bypass line that passes through said accumulator; and

a valve means that connects said bypass line in said circuit during said subsequent cycle so that said gasified refrigerant bypasses said condenser and passes through said accumulator to convert said accumulated liquefied refrigerant to a gaseous state.

10. The ice-making machine of claim 9, wherein said accumulator is disposed between said evaporator and said compressor.

11. The ice-making machine of claim 9, wherein said valve means disconnects said bypass line before another freeze cycle starts.

12. The ice-making machine of claim 9, wherein said subsequent cycle is a harvest cycle in which ice formed on said evaporator during said freeze cycle is harvested.

13. The ice making machine of claim 11, further comprising a controller that controls the operation of said valve means.