JPH07103625A - Method for operating ice making machine - Google Patents

Abstract

PURPOSE:To rapidly finish an ice separation cycle and prevent an ice from getting out of shape as far as possible even with a structure by a liquid injection method. CONSTITUTION:There are provided a cooler 1 disposed in an ice making unit, condenser 14 for feeding liquefied refrigerant to the cooler 1 through a pressure reducing means 13, compressor 15 for compressing vaporized refrigerant from the cooler 1 to send it to the condenser 14, hot gas pipe 16 for feeding delivery gas before being fed to the condenser 14 directly to the inlet side of the cooler 1, and first solenoid valve 17 provided midway in the pipe 16. Further there are provided a pipe 18 which is branched from a pipe 24 interconnecting the condenser 14 and the means 13 to feed a part of liquid refrigerant to the low pressure side in the compressor 15, second solenoid valve 19 provided midway in the pipe 18, and outside air temperature sensor 20. And at the time of making ice, water for making ice is circulated to an ice making unit to make ice, and when outside temperature is lower than a set value, the second solenoid valve 19 is closed and when outside temperature is higher than the value, the second solenoid valve is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice making machine which alternately makes ice making and ice making to make ice and cools the compressor by supplying a part of a liquefied refrigerant to a low pressure side inside the compressor. The present invention relates to an operation method of an ice making machine equipped with a liquid injection circuit.

[0002]

2. Description of the Related Art Conventionally, this type of ice making machine uses R12 as a refrigerant.
Alternatively, R502 was used for the refrigeration cycle to perform ice making and ice releasing, but due to recent CFC regulations, switching to alternative refrigerants is being carried out at all companies. Among them, R22 and R1
34a is used as an alternative refrigerant, but among them, the R22 compressor that has been conventionally used has been widely used because it has already been developed from small size to large size. In the case of this R22 compressor, the fairness is 5-264.
For the purpose of suppressing the rise in discharge gas temperature shown in Japanese Patent No. 35, a part of the liquefied refrigerant is supplied to the low pressure side inside the compressor,
Therefore, a liquid injection method of evaporating and cooling the compressor is adopted.

[0003]

[Problems to be Solved] However, in this liquid injection, a part of the liquefied refrigerant is supplied to the low pressure side inside the compressor and evaporated there to cool the compressor. In the ice making cycle, the compressor is used. However, in the deicing cycle in which the cooler is heated by hot gas to release the ice, the vaporized refrigerant that has been compressed into high temperature and high pressure before flowing into the condenser is cooled by the cooler. The liquefied refrigerant is supplied to the low-pressure side inside the compressor and evaporated there to cool the compressor. Was able to send the vaporized refrigerant that became high temperature and high pressure to the cooler, but after that (after about 40 seconds in the experiment), the refrigerant temperature dropped sharply, and the deicing cycle could be completed in about 3 minutes at room temperature. Things Also it takes 5 minutes. as a result,
As the time per ice making cycle is extended, the number of cycles per day is reduced, which leads to a decrease in the amount of ice making per day, and the time until the ice formed from the cooler is released becomes longer, so cooling is performed. There was a problem that the ice in the part that was in contact with the container was unraveled excessively, and the ice became a shapeless shape.

The present invention has been made in view of the above-mentioned problems, and even with a liquid injection type structure, the ice removal cycle can be quickly terminated and the shape of ice is prevented from collapsing as much as possible. The present invention provides a method of operating an ice maker for the purpose of achieving the above.

[0005]

As a means for achieving the above-mentioned object, the invention of claim 1 of the present application is a liquefied refrigerant through a cooler arranged in an ice making section and a decompression means in the cooler. And a compressor that supplies the compressed vaporized refrigerant from the cooler and sends the compressed vaporized refrigerant to the condenser, and the compressed vaporized refrigerant that has not flowed into the condenser directly flows into the inlet side of the cooler. A hot gas pipe, a first solenoid valve provided in the middle of the hot gas pipe, and a refrigerant pipe connecting the condenser and the pressure reducing means to part of the liquefied refrigerant to the low pressure side inside the compressor. A bypass pipe for supply, a second solenoid valve provided in the middle of the bypass pipe, and an outside air temperature sensor for detecting the outside air temperature are provided, and ice making water is circulated in the ice making section during ice making operation. When the outside air temperature is lower than the set value, Closes the second electromagnetic valve, is higher than the set value is to provide a method of operating an ice making machine which opens the second solenoid valve.

The invention according to claim 2 of the present application includes a cooler arranged in the ice making section, a condenser for supplying the liquefied refrigerant to the cooler via a pressure reducing means, and a vaporized refrigerant from the cooler. A compressor that compresses and sends out to the condenser, a hot gas pipe that directly flows the compressed vaporized refrigerant before flowing into the condenser into the inlet side of the cooler, and a hot gas pipe provided in the middle of the hot gas pipe A first solenoid valve, a bypass pipe branched from a refrigerant pipe connecting the condenser and the pressure reducing means to supply a part of the liquefied refrigerant to the low pressure side inside the compressor, and a bypass pipe provided in the middle of the bypass pipe No. 2 solenoid valve and a condensing temperature sensor for detecting the condensing temperature, and during the ice making operation, ice making water is circulated in the ice making section to make ice, and when the condensing temperature is lower than a set value, the second electromagnetic valve is used. Second solenoid valve when the valve is closed and higher than the set value There is provided a method of operating an ice making machine which is opened.

Further, the invention of claim 3 of the present application comprises a cooler arranged in the ice making section, a condenser for supplying a liquefied refrigerant to the cooler via a pressure reducing means, and a vaporized refrigerant from the cooler. A compressor that compresses and sends out to the condenser, a hot gas pipe that directly flows the compressed vaporized refrigerant before flowing into the condenser into the inlet side of the cooler, and a hot gas pipe provided in the middle of the hot gas pipe A first solenoid valve, a bypass pipe branched from a liquefied refrigerant pipe connecting the condenser and the pressure reducing means to supply a part of the liquefied refrigerant to the low pressure side inside the compressor, and a bypass pipe provided in the middle of the bypass pipe. A second electromagnetic valve is provided, and at the time of ice making operation, water for ice making is circulated through the ice making part to make ice,
An ice making machine is operated by heating the cooler with hot gas to remove ice, opening the second solenoid valve during the ice making operation, and closing the second solenoid valve during the ice making operation. It is provided.

Further, according to the invention of claim 4 of the present application, a cooler arranged in the ice making section, a condenser for supplying the liquefied refrigerant to the cooler via a pressure reducing means, and a vaporized refrigerant from the cooler are provided. A compressor that compresses and sends out to the condenser, a hot gas pipe that directly flows the compressed vaporized refrigerant before flowing into the condenser into the inlet side of the cooler, and a hot gas pipe provided in the middle of the hot gas pipe A first solenoid valve, a bypass pipe branched from a liquefied refrigerant pipe connecting the condenser and the pressure reducing means to supply a part of the liquefied refrigerant to the low pressure side inside the compressor, and a bypass pipe provided in the middle of the bypass pipe. A second electromagnetic valve is provided, and ice-making water is circulated through the ice-making unit to make ice, and then the cooler is heated by hot gas to remove ice, and a second electromagnetic valve is operated for a predetermined time from the ice-making operation. Open the valve and release the valve from the specified time before the start of ice removal operation. There is provided a method of operating an ice making machine for closing the second solenoid valve to end of operation.

[0009]

In the invention of claim 1 of the present application, when the outside air temperature is lower than the set value, the refrigerant is sent to the condenser by the compressor, and the liquefied refrigerant is supplied to the cooler from the condenser through the pressure reducing means. The refrigerant is circulated so that the vaporized refrigerant from the cooler flows into the compressor, and when the outside air temperature is higher than the set temperature, the second solenoid valve is opened to partially discharge the liquefied refrigerant to the compressor. Operates so that it can flow to the low pressure side and cool the compressor.

Further, in the invention of claim 2, when the condensing temperature is lower than the set temperature, the compressor sends the refrigerant to the condenser, and the liquefied refrigerant is cooled from the condenser via the pressure reducing means. The refrigerant is circulated so that the vaporized refrigerant from the cooler flows into the compressor, and when the condensation temperature is higher than the set temperature, the second solenoid valve is opened to partially discharge the liquefied refrigerant. It flows into the low pressure side of the compressor and operates so that it can be cooled.

Further, in the invention of claim 3, during the ice making operation, the refrigerant is sent to the condenser by the compressor, and the liquefied refrigerant is supplied from the condenser to the cooler through the pressure reducing means to cool the condenser. Refrigerant circulation is performed so that the vaporized refrigerant from the compressor flows into the compressor. During the ice making operation, the second solenoid valve is opened to allow a part of the liquefied refrigerant to flow into the low pressure side of the compressor and compress it. Operate the machine so that it can be cooled.

Further, in the invention of claim 4, the refrigerant is sent to the condenser by the compressor from a predetermined time before the ice removing operation is started during the ice making operation to the end of the ice removing operation, and the ice removing operation is performed. Liquefied refrigerant is supplied to the cooler from the condenser through the decompression means from a predetermined time before the start of operation, and the refrigerant is circulated so that the vaporized refrigerant from the cooler flows into the compressor, and during other ice making operations. First, the second solenoid valve is opened to allow a part of the liquefied refrigerant to flow into the low pressure side of the compressor, and the compressor is operated so that it can be cooled.

[0013]

1 is a circuit diagram showing a refrigeration cycle according to the invention of claim 1 of the present application, FIG. 2 is a circuit diagram showing a refrigeration cycle of the invention of claim 2 of the present application, and FIG. 3 is an invention of claim 1 of the present application. 4 is a time chart of the invention of claim 2 of the present application, FIG. 5 is a time chart of the invention of claim 3 of the present application,
6 is a time chart of the invention of claim 4 of the present application, FIG. 7 is a side view of an ice making device including the water tray of the present invention, and FIG. 8 is a perspective view of the ice making device in a tilted state of the water tray.

The outline structure of the reverse cell type ice making device will be described with reference to FIGS. 7 and 8. Reference numeral 1 is a cooler having a large number of partitioned ice making chambers 1A that open downward. On the lower side of the cooler 1, that is, on the opening surface side of the ice making chamber 1A, there is a rotation fulcrum 3 on the rear side, and on the front side, a drive motor 4A and a drive cam 4 are provided.
A water tray 5 of the present invention is provided which is provided with a drive unit 4 including B and a coil spring 4C, and is configured to be tiltable. Further, the water tray 5 is tilted together with the water tray 5 below the water tray 5. A water tank 6 having a movable upper surface opening is provided.

Thus, the water tray 5 has a water supply port 9 to which a flexible water supply pipe 8 of an external water system having a water supply solenoid valve 7 is connected.
It has an ice making water flow-down port 12 to which a discharge pipe 11 of a circulation pump 10 whose suction side is connected to a water tank 6 is connected, and which flows through a water supply pipe 8 from a water supply port 9 and an inlet 12 The ice making water in the water tank 6 is guided to the water tray 5. A water level detection device 25 is provided in the water tray 5, and the water supply solenoid valve 7 is controlled to be closed when the water level detection device 25 detects full water. A water temperature sensor 26 for detecting the water temperature is provided in the water tank 6.

A refrigerant circuit configuration of the above-described reverse cell type ice making machine will be described with reference to FIGS. 1 and 2. still,
The solid arrows in FIGS. 1 and 2 indicate the flow of the refrigerant during the ice making operation, and the dotted arrows indicate the flow of the refrigerant during the ice removing operation. As a configuration, a cooler 1 for introducing a liquefied refrigerant, an expansion valve 13 for detecting a temperature at an outlet side of the cooler 1 to control a refrigerant flow rate, and the expansion valve 1 for the cooler 1 are provided.
3, a condenser 14 for supplying a liquefied refrigerant through the receiver tank 22 and the dry core 23, a condenser cooling fan 25 for cooling the condenser 14, and a vaporized refrigerant from the cooler 1 through an accumulator 26. A compressor 15 for inflowing, compressing and sending out to the condenser 14, and a hot gas pipe 16 for directly injecting the compressed vaporized refrigerant before flowing into the condenser 14 into the inlet side of the cooler 1, A first solenoid valve 17 provided in the middle of the hot gas pipe 16,
Refrigerant pipe 2 connecting the expansion valve 13 from the condenser 14
A bypass pipe 18 branched from 4 to supply a part of the liquefied refrigerant to the low pressure side inside the compressor 15 to cool the compressor 15;
The second solenoid valve 19 provided in the middle of the bypass pipe 18
And a throttle device 27 that is provided in the bypass pipe 18 and throttles the amount of the refrigerant before flowing into the compressor 15. Further, numeral 20 in FIG. 1 is for detecting the outside air temperature by the outside air temperature sensor, and numeral 21 in FIG. 2 is for detecting the condensation temperature by the condensation temperature sensor. Since the basic circuit configuration is the same from the invention of claim 1 to the invention of claim 4,
The circuit configuration will be described only with reference to FIGS. 1 and 2.

Next, the operation of the invention of claim 1 will be described with reference to the time chart of FIG. After the start of ice making, the water supply solenoid valve 7 is opened to supply water to the ice making water circulation system, and the water level detecting device 2
When the water is supplied to the predetermined water level by 5, the water supply solenoid valve 7 is closed to complete the water supply. The compressor 15, the condenser cooling fan 25, and the circulation pump 10 of the ice making water circulation system operate to perform ice making operation. When the water temperature sensor 26 detects that the water temperature of the ice making water circulation system has dropped to a predetermined water temperature, the first ice making timer starts counting. At this time, the ambient temperature is detected by the outside air temperature sensor 20, but the detected temperature is
When the temperature is higher than a predetermined temperature (for example, 30 ° C.), the second electromagnetic valve 19 of the bypass pipe 18 is opened to supply the liquefied refrigerant to the low pressure side of the compressor 15 to cool the compressor 15, and it is detected. When the temperature is lower than the predetermined temperature (for example, 30 ° C.), the second electromagnetic valve 19 of the bypass pipe 18 is closed to stop the supply of the liquefied refrigerant to the low pressure side of the compressor. Then the first
When the ice making timer of (1) counts a predetermined number of times, the ice making operation is terminated and the ice making operation is started. When the ice removing operation is started, the first electromagnetic valve 17 of the hot gas pipe 16 is opened to supply the hot gas to the cooler 1, and the driving device 4 is operated to open the water tray 5 to open the ice cubes in the cooler 1. De-ice. Even in this operation, the ambient temperature is detected by the outside air temperature sensor 20, but when the detected temperature is higher than a predetermined temperature (for example, 30 ° C.), the second electromagnetic valve 19 of the bypass pipe 18 is opened to open the compressor. When the liquefied refrigerant is supplied to the low pressure side of 15 to cool the compressor 15 and the detected temperature is lower than a predetermined temperature (for example, 30 ° C.), the second solenoid valve 19 of the bypass pipe 18 is closed. The supply of liquefied refrigerant to the low pressure side of the compressor is stopped. When the ice cubes are deiced from the cooler 1, the drive device 4 is operated again to close the water tray 5, and the next ice making operation is started.

Next, the operation of the invention of claim 2 will be described based on the time chart of FIG. After the start of ice making, the water supply solenoid valve 7 is opened to supply water to the ice making water circulation system, and the water level detecting device 2
When the water is supplied to the predetermined water level by 5, the water supply solenoid valve 7 is closed to complete the water supply. The compressor 15, the condenser cooling fan 25, and the circulation pump 10 of the ice making water circulation system operate to perform ice making operation. When the water temperature sensor 26 detects that the water temperature of the ice making water circulation system has dropped to a predetermined water temperature, the first ice making timer starts counting. At this time, the condensing temperature sensor 21 detects the condensing temperature, but the detected temperature is
When the temperature is higher than the predetermined temperature, the second electromagnetic valve 19 of the bypass pipe 18 is opened to supply the liquefied refrigerant to the low pressure side of the compressor 15 to cool the compressor 15, and the detected temperature is
When the temperature is lower than the predetermined temperature, the second electromagnetic valve 19 of the bypass pipe 18 is closed to stop the supply of the liquefied refrigerant to the low pressure side of the compressor. After that, when the first ice making timer counts a predetermined number of times, the ice making operation is ended and the ice making operation is started.
When the ice removing operation is started, the first electromagnetic valve 17 of the hot gas pipe 16 is opened to supply the hot gas to the cooler 1, and the driving device 4 is operated to open the water tray 5 to open the ice cubes in the cooler 1. De-ice. In this operation as well, the condensation temperature sensor 21 detects the condensation temperature, but if the detected temperature is higher than a predetermined temperature, the second solenoid valve 19 of the bypass pipe 18 is detected.
Is opened to supply the liquefied refrigerant to the low pressure side of the compressor 15 to cool the compressor 15. When the detected temperature is lower than a predetermined temperature, the second solenoid valve 19 of the bypass pipe 18 is closed. The supply of liquefied refrigerant to the low pressure side of the compressor is stopped. When the ice cubes are deiced from the cooler 1, the drive device 4 is operated again to close the water tray 5, and the next ice making operation is started.

Next, the operation of the invention of claim 3 will be described with reference to the time chart of FIG. At the same time as the start of the ice making operation after the end of the ice removing operation, the second electromagnetic valve 19 of the bypass pipe 18 is opened to supply the liquefied refrigerant to the low pressure side of the compressor 15 to cool the compressor 15. The water supply solenoid valve 7 is opened to supply water to the ice making water circulation system, and when the water level detection device 25 supplies water to a predetermined water level, the water supply solenoid valve 7 is closed to complete the water supply. Compressor 15 and condenser cooling fan 25
The circulation pump 10 of the ice making water circulation system operates to perform ice making operation. When the water temperature sensor 26 detects that the water temperature of the ice making water circulation system has dropped to a predetermined water temperature, the first ice making timer starts counting. After that, when the first ice making timer counts a predetermined number of times, the ice making operation is finished and the ice making operation is started, but at the same time as the start of the ice making operation, the second solenoid valve 19 of the bypass pipe 18 is closed. The supply of liquefied refrigerant to the low pressure side of the compressor is stopped. When the ice removing operation is started, the first solenoid valve 17 of the hot gas pipe 16 is opened to open the cooler 1
Hot gas is supplied to the device and the drive device 4 is operated to open the water tray 5 to deice the ice cubes in the cooler 1. Cooler 1
When the ice cubes are removed from the ice cube, the drive device 4 is operated again to drive the water tray 5
Is closed and the next ice making operation is started. Next, the invention of claim 4 will be described based on the timing chart of FIG.
Simultaneously with the start of the ice making operation, the second solenoid valve 19 of the bypass pipe 18 is opened to supply the liquefied refrigerant to the low pressure side of the compressor 15 to cool the compressor 15, and the second ice making timer gives a predetermined time. The second solenoid valve 19 is kept open until the time elapses. Simultaneously with the start of ice making, the water supply solenoid valve 7 is opened to supply water to the ice making water circulation system, and when the water level detecting device 25 supplies water to a predetermined water level, the water supply solenoid valve 7 is closed to complete the water supply. The compressor 15, the condenser cooling fan 25, and the circulation pump 10 of the ice making water circulation system operate to perform ice making operation. When the water temperature sensor 26 detects that the water temperature of the ice making water circulation system has dropped to a predetermined water temperature, the first ice making timer starts counting. When the second ice making timer measures a predetermined time during the ice making operation, the second electromagnetic valve 19 is closed. After that, when the first ice making timer counts a predetermined number of times, the ice making operation is ended and the ice making operation is started. When the ice removing operation is started, the first electromagnetic valve 17 of the hot gas pipe 16 is opened to supply the hot gas to the cooler 1, and the driving device 4 is operated to open the water tray 5 to open the ice cubes in the cooler 1. De-ice. When ice cubes are deiced from the cooler 1, the drive device 4 is operated again to close the water tray 5 to shift to the next ice making operation, and at the same time, the second solenoid valve 19 is opened to the low pressure side of the compressor 15. The liquefied refrigerant is supplied to cool the compressor 15.

Although the reverse cell type ice making machine is described in this embodiment, the reverse cell type ice making machine may be used in an auger type ice making machine, a falling type ice making machine and the like without departing from the gist of the present invention.

[0021]

According to the invention of claim 1 of the present application, by performing the operation control as described above, when the outside air temperature is lower than the predetermined temperature, a normal refrigeration cycle is performed, and when the outside air temperature is higher than the predetermined temperature. In addition, a part of the liquefied refrigerant can be made to flow into the low pressure side of the compressor to cool the compressor,
It is possible to shorten the ice-free time, prevent the ice-making ability from decreasing due to the outside air temperature, and stably provide high-quality ice.

Further, in the invention of claim 2 of the present application, when the condensing temperature is lower than the predetermined temperature, a normal refrigeration cycle is performed, and when the condensing temperature is higher than the predetermined temperature, a part of the liquefied refrigerant is compressed. It can flow into the low pressure side of the machine to cool the compressor, shorten the ice removal time, prevent the ice making capacity from decreasing due to the condensation temperature, and stabilize the quality of ice. Can be provided.

Further, according to the invention of claim 3 of the present application, during the ice making operation, the liquefied refrigerant is caused to flow to the low pressure side of the compressor to cool the compressor, and the cooling efficiency of the cooler is improved to perform an efficient ice making operation. At the same time, since hot gas flows through the cooler during ice removal operation, high-temperature and high-pressure refrigerant is allowed to flow without cooling the compressor, and ice removal is efficiently performed. Therefore, it is possible to efficiently and stably control the operations of ice making and ice removing, and to stably provide high quality ice.

Further, according to the invention of claim 4 of the present application, the liquefied refrigerant can be made to flow to the low pressure side of the compressor until the middle of the ice making operation to cool the compressor. Since the cooling of the compressor is stopped for a predetermined time before the operation starts, when the operation shifts to the ice-free operation where cooling of the compressor is unnecessary, a high-temperature and high-pressure refrigerant can be made to flow from the initial stage for cooling, ice making, Since the ice-free operation can be efficiently and stably controlled, it is possible to stably provide high-quality ice.

[0025]

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a refrigeration cycle of the invention of claim 1 of the present application.

FIG. 2 is a circuit diagram showing a refrigeration cycle according to the invention of claim 2 of the present application.

FIG. 3 is a time chart of the invention of claim 1 of the present application.

FIG. 4 is a time chart of the invention of claim 2 of the present application.

FIG. 5 is a time chart of the invention of claim 3 of the present application.

FIG. 6 is a time chart of the invention of claim 4 of the present application.

FIG. 7 is a side view of an ice making device including the water tray of the present invention.

FIG. 8 is a perspective view of the ice making device in a tilted state of the water tray.

[Explanation of reference numerals] 1 cooler 2 ice making section 13 decompression means 14 condenser 15 compressor 16 hot gas pipe 17 first solenoid valve 18 bypass pipe 19 second solenoid valve 20 outside air temperature sensor 21 condensation temperature sensor 24 refrigerant pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F25C 1/00 301 Z 1/04 302 302 Z

Claims (4)

[Claims] 1. A cooler arranged in an ice making section, a condenser for supplying a liquefied refrigerant to the cooler via a pressure reducing means, and a compressor for compressing the vaporized refrigerant from the cooler and sending it to the condenser. Machine, a hot gas pipe for directly flowing the compressed vaporized refrigerant before flowing into the condenser to the inlet side of the cooler, a first solenoid valve provided in the middle of the hot gas pipe, and the condensing Bypass pipe for branching from a refrigerant pipe connecting the pressure reducing means to the compressor and supplying a part of the liquefied refrigerant to the low pressure side inside the compressor, a second solenoid valve provided in the middle of the bypass pipe, and an outside air temperature An outside air temperature sensor for detecting the temperature, and during the ice making operation, the ice making water is circulated in the ice making section to make ice, and when the outside air temperature is lower than the set value, the second solenoid valve is closed to set the value. When it is higher, the second solenoid valve is opened. How to operate an ice maker. 2. A cooler arranged in the ice making section, a condenser for supplying the liquefied refrigerant to the cooler via a pressure reducing means, and a compressor for compressing the vaporized refrigerant from the cooler and sending it to the condenser. Machine, a hot gas pipe for directly flowing the compressed vaporized refrigerant before flowing into the condenser to the inlet side of the cooler, a first solenoid valve provided in the middle of the hot gas pipe, and the condensing Bypass pipe for branching from the refrigerant pipe connecting the pressure reducing means to the pressure reducing means and supplying a part of the liquefied refrigerant to the low pressure side inside the compressor, a second solenoid valve provided in the middle of the bypass pipe, and a condensing temperature Equipped with a condensing temperature sensor to detect,
During the ice making operation, the ice making water is circulated in the ice making section to make ice, and the second solenoid valve is closed when the condensation temperature is lower than the set value, and the second solenoid valve is opened when the condensation temperature is higher than the set value. A method for operating an ice maker, which comprises a valve. 3. A cooler arranged in the ice making section, a condenser for supplying a liquefied refrigerant to the cooler via a pressure reducing means, and a compressor for compressing the vaporized refrigerant from the cooler and sending it to the condenser. Machine, a hot gas pipe for directly flowing the compressed vaporized refrigerant before flowing into the condenser to the inlet side of the cooler, a first solenoid valve provided in the middle of the hot gas pipe, and the condensing A bypass pipe that branches from a liquefied refrigerant pipe connecting the pressure reducing means to the pressure reducing means and supplies a part of the liquefied refrigerant to the low pressure side inside the compressor; and a second solenoid valve provided in the middle of the bypass pipe. During the ice making operation, the ice making water is circulated in the ice making section to make ice, and the cooling device is heated by hot gas to remove the ice, and the second solenoid valve is opened and released during the ice making operation. The second electromagnetic valve is closed during ice operation. how to drive. 4. A cooler arranged in the ice making section, a condenser for supplying a liquefied refrigerant to the cooler via a pressure reducing means, and a compressor for compressing the vaporized refrigerant from the cooler and sending it to the condenser. Machine, a hot gas pipe for directly flowing the compressed vaporized refrigerant before flowing into the condenser to the inlet side of the cooler, a first solenoid valve provided in the middle of the hot gas pipe, and the condensing A bypass pipe that branches from a liquefied refrigerant pipe connecting the pressure reducing means to the pressure reducing means and supplies a part of the liquefied refrigerant to the low pressure side inside the compressor; and a second solenoid valve provided in the middle of the bypass pipe. After ice-making water is circulated in the ice-making unit to make ice, the ice cooler is heated by hot gas to remove ice, and the second solenoid valve is opened for a predetermined time from ice-making operation to perform ice-release operation. The second solenoid valve is closed from a predetermined time before the start until the end of the ice removal operation. A method for operating an ice maker, which comprises a valve.