JP3133539B2 - Ice machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice maker called a so-called inverted cell type ice maker.

[0002]

2. Description of the Related Art Conventionally, this kind of ice making machine is disclosed in
As shown in Japanese Patent No. 91667 (F25C1 / 22), a tiltable water tray is provided below a cooler that defines a plurality of downwardly opening ice-making chambers, and the water tray closes the ice-making chamber. At the horizontal closing position, the ice making process is performed by fountains into each ice making chamber from the fountain holes formed on the surface of the water tray, and the high temperature and high pressure refrigerant from the compressor is supplied to the cooler at the inclined open position where the water tray opens the ice making chamber. It is configured to flow, heat, and perform the de-icing process.

The fountain is supplied to the ice making chamber by supplying ice making water in a water tank to a water tray by a circulation pump. Water supply to the water tank is controlled by a water supply solenoid valve. Is started when the horizontal position is reached. Also, if the circulation pump is operated before the ice making water is sufficiently stored in the water tank, the circulation pump is damaged by causing air compression, so that the circulation pump is operated with a delay of a predetermined time from the start of the water supply. Was configured to.

[0004]

As described above, in the prior art, the water tray is moved back from the end of the deicing, and the water supply is started after returning to the predetermined horizontal closed position, and the circulation pump is further delayed thereafter. Therefore, there is a problem that the time required for the entire ice making process is prolonged and the improvement of the ice making capacity is hindered accordingly.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art. In a so-called inverted cell type ice making machine, the water supply to a water tank is promptly terminated to improve the ice making capacity. With the goal.

[0006]

That is, an ice making machine according to the first aspect of the present invention comprises a cooler in which a plurality of downwardly opening ice making compartments are formed, and a tiltable water tray for closing each ice making compartment. An ice making process in which ice making water in a water tank is sprayed from a fountain hole formed on the surface of the water tray by a circulation pump into each of the ice making chambers in a state where the water tray is at a predetermined horizontal closed position, and ice making is performed.
An ice-removing process of heating the cooler and de-icing while the water tray is at the predetermined inclined open position is repeated, and a water supply valve provided in a water supply path to the water tank, an ice-making process, Control means for controlling the operation of the ice making machine in the ice-removing process, wherein the control means starts the return of the water tray from the end of de-icing and before the water tray returns to the horizontal closed position. The water supply valve is opened to start supplying water to the water tank.

According to a second aspect of the present invention, there is provided an ice making machine including a cooler in which a plurality of downwardly opening ice making chambers are formed and a tiltable water tray closing each ice making chamber. The ice making process in which the ice making water in the water tank is sprayed from the fountain holes formed on the surface of the water tray into the respective ice making chambers by the circulation pump in the state where the water tray is in the predetermined horizontal closed position and ice is made, and the water tray is in a predetermined inclined open position The deicing process of heating the cooler in a certain state to perform deicing is repeated, and the water supply valve provided in the water supply path to the water tank and the operation of the ice making machine in the ice making process and the deicing process are repeated. Control means for controlling the power supply, and power supply frequency detection means for detecting a power supply frequency and outputting a power supply frequency signal to the control means. The water tray returns to the horizontal closed position based on the signal Open the water supply valve from the predetermined time before that, it is to start the water supply to the water tank.

[0008]

According to the ice making machine of the first aspect of the present invention, the control means starts the return of the water tray from the end of the deicing, and opens the water supply valve before the water tray returns to the horizontal closed position. Since the water supply to the tank is started, the water supply to the water tank is performed quickly. Therefore, the operation of the circulating pump can be started earlier than before, whereby the time of the entire ice making process can be shortened and the ice making capacity of the ice making machine can be improved.

Further, according to the ice making machine of the invention of claim 2,
In addition to the above, the control means opens the water supply valve from a predetermined time before the water tray returns to the horizontal closed position based on the power supply frequency signal from the power supply frequency detection means. Here, the power frequency is 5
At 0HZ and 60HZ, the time from the end of de-icing until the water tray starts moving backward and returns to the horizontal closed position differs. According to the present invention, the control means is controlled based on the power supply frequency signal. Then, the water supply is automatically started from a point in time which is calculated a predetermined time ago by calculating backward from the time from the start of the return movement of the water tray to the return to the horizontal closed position. Therefore, regardless of the power supply frequency, the inclination angle of the water tray at the time when water supply is started can be maintained within a substantially constant range, and the amount of water stored in the water tank at the time when the circulation pump is operated is constant. It can be.

[0010]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an electric circuit diagram of the control device 20 of the ice making machine I of the present invention, and FIG. Ice machine I
Is a so-called inverted cell type ice making machine, which has a plurality of ice making chambers 1A opened downward, a cooling device 1 having an evaporating pipe 2 of a cooling device arranged on the outer surface of an upper wall, and a predetermined horizontal position. At the closed position, each ice making chamber 1A is closed with a sufficient margin from below, and a water tray 5 having a fountain hole 3 and a return hole 4 corresponding to each ice making chamber 1A formed on the surface, and fixed to the water tray 5, A water tank 6 communicating with the hole 4, a circulating pump 9 for spouting water in the water tank 6 from the fountain hole 3 through a water supply pipe 7 and a distribution pipe 8 and circulating the water to each ice making chamber 1 </ b> A, A drive unit 11 including a high gear ratio decelerating motor 10 capable of forward and reverse rotation for tilting and returning, and a sprinkler 13 for spraying water on the surface of the water tray 5 when a water supply solenoid valve 12 as a water supply valve is opened.
And a float tank 14A communicating with the bottom of the water tank 6.
A water level switch WLSW is operated by a float 14B in the inside, and a water level detecting device 14 and the like for detecting a predetermined full water level of the water tank 6 are constituted.

The mounting plate 1 fixed to the support beam 15
The first and second arms 17A and 17A extending in opposite directions are attached to the output shaft of the reduction motor 10 supported by
7B, and a coil spring 18 attached to the end of the first arm 17A of the drive cam 17
Is connected to the side of the water tray 5 and the rear part of the water tray 5 is supported by a rotating shaft 19.

ASW is a water tray position detection switch for detecting the horizontal closed position and the inclined open position of the water tray 5 by opening and closing the contacts. The water dish position detection switch ASW is connected to the first and second arms 1 of the drive cam 17.
When the drive cam 17 rotates counterclockwise in FIG. 2 due to the forward rotation of the deceleration motor 10, the second arm 17B is set when the water tray 5 is at the inclined open position. Is a water dish position detection switch ASW
, Whereby the contact point of the water tray position detection switch ASW is closed and switched to the reverse side.

When the drive cam 17 rotates clockwise in FIG. 2 due to the reverse rotation of the deceleration motor 10, the first arm 17A is set to the water tray position detection switch ASW when the water tray 5 is at the horizontal closed position. The contact of the water tray position detection switch ASW is thereby opened and switched to the tilting side. Next, in the control device 20 of FIG. 1, the following circuits are connected to the power supply AC via the operation switch 35. That is, the compressor 21 constituting the cooling device is connected in series with the relay R1, and the condenser cooling fan 22 for cooling the condenser (not shown) of the cooling device is connected to the relay R2.
And are connected in series. The circulation pump 9 has a relay R
3 is connected in series with the relay R7 and controls the supply of hot gas (high-temperature and high-pressure gas refrigerant) to the evaporating pipe 2 of the cooler 1. Valve 12 is connected in series with relay R4. The deceleration motor 10 is connected in series with a relay R5 and a switching relay R6. This switching relay R6 has a contact a
Side, the deceleration motor 10 rotates forward, and switches to the contact b side to rotate the deceleration motor 10 reversely.

These relays R1 to R7 are controlled by a general-purpose microcomputer 25 as control means. The input of the microcomputer 25 is connected to the water level switch WLSW and the water tray position detection switch ASW, and closes a contact when a predetermined amount of ice in an ice storage (not shown) located below in FIG. 2 is detected. The ice storage switch BSW is connected. The input of the microcomputer 25 is connected to a sensor 26 for detecting the temperature of the cooler 1 and the sensor 31 for detecting the temperature of the condenser, and a monitor 27 is connected to the output of the microcomputer 25.

Further, a power supply frequency detecting circuit 36 as power supply frequency detecting means is connected to the power supply AC. The power supply frequency detection circuit 36 has a power supply AC frequency of 50H.
In the case of Z, 50 pulses are output per second, and in the case of 60 Hz, 60 pulses are output to the microcomputer 25 as a power supply frequency signal. The microcomputer 25 has a counter 25C for counting the number of pulses per second of the power supply frequency signal. Based on the count of the counter 25C, it is determined whether the frequency of the connected power supply AC is 50HZ or 60HZ. And know.

Next, the operation of the ice maker I according to the present invention will be described with reference to the flowcharts showing the programs of the microcomputer 25 in FIGS. 3 and 4 and the operation process diagrams of the ice maker I shown in FIGS. . After installing the ice maker I, or for long-term non-use,
Is cut off, the operation switch 35 is closed again and the ice making machine I is closed.
It is assumed that the power is turned on (ON). At this time, water plate 5
The position of has not been determined, the horizontal closed position, or the inclined open position, or in the middle of the inclined state,
It is considered that the tilting state is in the middle of tilting and in the middle of returning.

However, such a state can be distinguished into two types depending on the open / close state of the contact of the water tray position detection switch ASW. That is, when the contact of the water tray position detection switch ASW is open and on the tilting side, the water tray 5 is in the horizontal closed position or in the middle of tilting, and the contact of the water tray position detection switch ASW is closed and is on the return side. At one time, the water tray 5 is in the inclined open position or in the middle of the backward movement.

Then, when the operation switch 35 is closed and the power supply AC is turned on (ON), the microcomputer 25 determines the state of the water tray position detection switch ASW in step S1, and the contact is opened and the microcomputer 25 is tilted. In some cases (Fig. 5
Situation. The water tray 5 is in the horizontal closed position or in the middle of tilting)
Proceeding to step S2, the relay R5 is closed and the switching relay R
6 is closed to the contact a side, the deceleration motor 10 is rotated forward, and the water tray 5 is tilted. Then, in step S4, the state of the water tray position detection switch ASW is determined again. If the switch is still on the tilting side, the process returns to step S2 to continue tilting. When the water tray 5 is at the predetermined inclined open position, the water tray position detection switch AS
When the contact of W is closed and reversed to the return side, the microcomputer 25 proceeds from step S4 to step S5, this time closing the switching relay R6 to the contact b side, and
Is reversed to start the backward movement of the water tray 5.

The microcomputer 25 then determines in step S6 whether it is 15 seconds before the water tray 5 is completely closed (horizontal closing position), and if not, proceeds to step S9 and again switches on the water tray position detection switch. The state of the ASW is determined, and if it is still on the return side, the process returns to step S5 to continue the return. Here, from the start of the return movement of the water tray 5 to the return to the horizontal closed position, 50 seconds, 60 seconds when the power supply AC is 50 HZ.
It takes 40 seconds for HZ. Microcomputer 25
Has grasped the frequency of the power supply AC based on the power supply frequency signal from the power supply frequency detection circuit 36 as described above.
In the case of HZ, it is 35 after starting the backward movement in step S5.
The determination 15 seconds before in step S6 is made based on whether or not seconds have elapsed, and in the case of 60 HZ, the determination 15 seconds before in step S6 is made based on whether 25 seconds have elapsed since the start of the backward movement in step S5. Do.

Then, 15 seconds before, the process proceeds from step S6 to step S7, where the relay R4 is closed and the water supply solenoid valve 12 is opened (ON). When the water supply solenoid valve 12 is opened, the sprinkler 1
Water is sprayed from 3 onto the surface of a water tray 5 and supplied to a water tank 6 mainly through a return hole 4. Then, in step S8, it is determined by the water level switch WLSW whether or not the water level in the water tank 6 has reached a predetermined full level.
Proceed to.

Thereafter, the water tray 5 is moved to the horizontal closed position (FIG. 2).
When the contact of the water tray position detection switch ASW is opened and inverted to the tilting side, the microcomputer 25 returns from step S9 to step S6, so that the return movement of the water tray 5 is stopped. . On the other hand, when the power supply AC is turned on (ON), the contact of the water tray position detection switch ASW is closed and on the return side (the situation of FIG. 5).
The microcomputer 25 proceeds from step S1 to step S3, closes the relay R5, closes the switching relay R6 to the contact b side, reverses the speed reduction motor 10, and moves the water The plate 5 is moved back. Thereafter, the process proceeds to step S6, and thereafter, as described above, step S9
, The return movement is continued until the water tray position detection switch ASW is inverted to the tilting side, and the water tray 5 is similarly stopped when the water tray 5 returns to the horizontal closed position.

As described above, when the power is turned on (ON), the microcomputer 25 determines the state of the water tray 5 according to the open / close state of the contact of the water tray position detection switch ASW.
If it is determined that the pan is in the horizontal closed position or in the middle of tilting,
Is tilted once, and then moved backward to a predetermined horizontal closing position. When it is determined that the water tray 5 is in the tilting open position or in the middle of the backward movement, the water tray 5 is moved backward to close the horizontal closing position. Position. In any case, according to the ice making machine I of the present invention, after the power is turned on, the water tray 5 is always initialized to the horizontal closed position.

Thereafter, when the water tank 6 is full, the process proceeds from step S7 to step S10 in FIG.
4, the water supply solenoid valve 12 is closed (OFF) to stop water supply to the water tank 6, and then the process proceeds to step S12, where the relays R3 and R7 are closed, and the circulation pump 9 is operated (O).
N) and open the hot gas solenoid valve 23 (ON).

When the circulating pump 9 is operated, the water in the water tank 6 is fountain from the fountain hole 3 into the ice making chamber 1A, and is circulated through the return hole 4 to the water tank 6. As a result, dust or water residue deposited or attached in the circulation channel is washed, and dust clogged in the fountain hole 3 is also removed. At this time, as described above, the microcomputer 25
Regardless of the frequency C (50 HZ, 60 HZ), the water tray 5 starts supplying water to the water tank 6 for a predetermined time, 15 seconds before the water tray 5 returns to the horizontal closing position. The amount of water stored in the water tank 6 when returning to the position becomes constant regardless of the power supply frequency. Here, when the amount of water stored in the water tank 6 is too small at the start of the operation of the circulation pump 9, there is a risk that the circulation pump 9 may be compressed by air and may be damaged. Even if it fluctuates, the amount of water stored in the water tank 6 at the start of the operation of the circulation pump 9 can be kept constant, so that such inconvenience can be solved.

If the water supply is started at a time when the water tray 5 and the water tank 6 are greatly inclined, the ice making water overflows from the water tank 6, but according to the present invention, the water supply at the time when the water supply is started is started. The inclination angle of the water dish 5 is set within a substantially constant range (60H
Z becomes steeper), so that stable water supply with less loss can be performed.

On the other hand, the microcomputer 25 determines in step S13 whether or not the count of a timer having the function has reached 30 seconds. If not, the microcomputer 25 returns to step S12 to continue the above-described cleaning. As described above, the ice maker I performs the first cleaning step after turning on the power, and cleans the inside of the circulating water channel. However, before the circulating pump 9 is operated, the water tray 5 is surely set to the horizontal closed position as described above. Therefore, inconvenience that water is fountain from the fountain hole 3 in a state where the water tray 5 is inclined is reliably prevented. Therefore, it is possible to prevent the inconvenience that the lower ice storage is flooded and the generated or subsequently generated ice is damaged.

After the cleaning is performed for 30 seconds, the microcomputer 25 proceeds from step S13 to step S14.
Then, the relay R1 is closed, the compressor 21 is started, and the process moves to the following deicing process. That is, the ice maker I does not start the compressor 21 during the first cleaning process after the power is turned on. Here, when the power is turned on immediately after the momentary power failure and the compressor 21 is operated at the same time, the pressure difference between the high pressure side and the low pressure side in the refrigerant circuit of the cooling device is large, and a large load is applied to the activation of the compressor 21. . Therefore, there is a danger that a start-up failure such as a failure to start the compressor 21 may occur in a state where the pressure difference is large, but in the present invention, the compressor 21 is not started during the first cleaning process after the power is turned on. Therefore, the difference between the high and low pressures of the refrigerant circuit is reduced during that time, and therefore, the occurrence of the above-described start-up failure is prevented.

In particular, the operation time of the water tray 5 (35 seconds or 2 seconds)
5 seconds) and the timer for setting the period for washing (30 seconds), the forced stop period of the compressor 21 is ensured, so that a special motor timer and a program of the microcomputer 25 as in the related art are not required. Ice machine I
The configuration of the control device 20 can be simplified. Further, cleaning before starting the compressor 21 is performed.
During the second, the microcomputer 25 opens the hot gas solenoid valve 23, so that the pressure in the refrigerant circuit is balanced more quickly, and the occurrence of the starting failure of the compressor 21 is more reliably prevented. become.

Then, in the de-icing process, the microcomputer 25 opens the relay R2 and the relay R3, stops the condenser cooling fan 22 and the circulation pump 9, and turns off the relay R5.
Then, the relay R7 is closed, the switching relay R6 is closed to the contact a side, the deceleration motor 10 is rotated forward, and the water tray 5 is tilted. Further, since the hot gas solenoid valve 23 is open, the hot gas discharged from the compressor 21 is circulated to the evaporating pipe 2 and the cooler 1 is heated.

When the water tray 5 is tilted to a predetermined tilt open position (fully open) as shown by a broken line in FIG.
7 is provided with a water tray position detection switch ASW.
The microcomputer 25 opens the relay R5 and stops the deceleration motor 10 to stop the tilting of the water tray 5 because the contact is reversed. When the water tray 5 is at the inclined open position, the circulating water in the water tank 6 is drained to a drain (not shown) located immediately below the water tank 6. The temperature of the cooler 1 captured by the sensor 26 is, for example, +
Judgment is made as to whether the temperature is higher than the de-icing completion temperature such as 9 ° C., and if it is higher, it is judged that deicing from the cooler 1 has been completed, and the relay R5 is closed and the switching relay R6 is closed to the contact b. The deceleration motor 10 is rotated in reverse to move the water tray 5 upward. Further, after opening the relay R7 and closing the hot gas solenoid valve 23, the hot gas refrigerant discharged from the compressor 21 is condensed and liquefied by the condenser, and decompressed by a pressure reducing device such as a capillary tube (not shown). The cooling of the cooler 1 is restarted by supplying it to the evaporating pipe 2 and evaporating it there.

When the water tray 5 returns to the predetermined horizontal closed position (fully closed position) as shown by the solid line in FIG. 2 by the return movement, the first arm 17A of the driving cam 17 comes into contact with the water tray position detection switch ASW. The microcomputer 25 opens the relay R5, stops the deceleration motor 10 to stop the water tray 5 from returning, and terminates the ice removal process. Then, the microcomputer 25 proceeds to step S1.
Proceeding to 5, the relay R1 is closed, and the following ice making process is performed while the compressor 21 is operating. The microcomputer 25 closes the relay R4 15 seconds before the water tray 5 is completely closed (horizontal closing position) and closes the water supply solenoid valve 12 as described above.
And water supply to the water tank 6 is started as described above.

In the ice making process, the hot gas refrigerant discharged from the compressor 21 is condensed and liquefied by the condenser.
After being decompressed by a decompression device such as a capillary tube (not shown), the pressure is supplied to an evaporating pipe 2, where it is evaporated to cool the cooler 1. In addition, the microcomputer 25
The condenser cooling fan 22 is operated while supplying water by closing the relays R2 and R4, and the relay R3 is closed with a delay of 10 to 30 seconds, and the circulation pump 9 is operated to remove water in the water tank 6. The ice making operation is started by circulating from the fountain hole 3 to each ice making room 1A.

Thereafter, the microcomputer 25 determines whether or not the water level switch WLSW is closed. When a predetermined amount of water is supplied into the water tank 6, and the water level switch WLSW detects a predetermined full water level and closes, the relay R4 is turned off. Open and close the water supply solenoid valve 12 to stop water supply. The microcomputer 25 is connected to the cooler 1 captured by the sensor 26.
When the temperature reaches, for example, 0 ° C., the microcomputer 25 starts the accumulation of an ice making timer provided as a function of the temperature.

The water supply to the water tank 6 is started by the water supply solenoid valve 12 15 seconds before the water tray 5 returns to the horizontal closed position. Therefore, the water level in the water tank 6 can be raised earlier and the water supply can be terminated as compared with the case where water supply is started after returning to the horizontal closed position as in the related art. Further, since the cooling of the cooler 1 is restarted from the start of the return movement of the water tray 5, the operation of the circulation pump 9 can be started earlier than before. Therefore, since the start timing of the ice making operation is advanced, the time required for the entire ice making process is shortened, thereby improving the ice making capability of the ice making machine I.

The ice making chamber 1 of the cooler 1 is operated by the ice making operation.
Ice is gradually generated in A, and when the integrated value of the ice making timer times out, the microcomputer 25 proceeds to step S16, opens the relays R2 and R3, and opens the condenser cooling fan 22 and the circulation pump 9 To stop. Next, the relays R5 and R7 are closed, and
The switching relay R6 is closed to the contact a side to rotate the deceleration motor 10 forward to start the tilting of the water tray 5, and the hot gas solenoid valve 23 is opened to circulate the hot gas to the evaporating pipe 2 so that the cooler 1 Is heated to move to a de-icing process of ice frozen in the ice making chamber 1A.

This de-icing process is performed in the same manner as described above. The microcomputer 25 determines whether or not the ice storage switch BSW is closed during the ice removal process. If a predetermined amount of ice is stored in an ice storage (not shown), the process proceeds to step S17, where the relay R1 and the relay R1 are relayed. R7 is opened, the operation of the compressor 21 is stopped, and the process shifts to the ice storage process. Then, after that, the ice in the ice storage decreases and the ice storage switch BSW
Is maintained until is closed, and when the ice storage switch BSW is closed, the ice making process is executed again.

Incidentally, the various times and the like shown in the embodiment are not limited thereto, and may be appropriately set according to the capacity and capacity of the ice making machine I.

[0038]

As described above in detail, according to the first aspect of the present invention, the control means starts the return movement of the water tray from the end of the deicing and the water supply valve before the water tray returns to the horizontal closed position. Is opened to start water supply to the water tank, so that water supply to the water tank can be performed quickly. Therefore, the operation of the circulation pump can be started earlier than in the past, whereby the time of the entire ice making process can be shortened, and the ice making capacity of the ice making machine can be improved. .

According to the second aspect of the present invention, in addition to the above, the control means controls the water supply valve from a predetermined time before the water tray returns to the horizontal closed position based on the power supply frequency signal from the power supply frequency detection means. Since it is opened, the amount of water stored in the water tank at the time when the circulation pump is operated can be constant regardless of the power supply frequency. Therefore, it is possible to prevent the occurrence of damage due to the air compression of the circulation pump, and to solve the problem that the ice making water supplied into the water tank overflows due to the start of the water supply too soon.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of a control device of an ice making machine according to the present invention.

FIG. 2 is a partially cutaway side view of the ice making machine.

FIG. 3 is a flowchart showing a program of a microcomputer.

FIG. 4 is a flowchart showing a program of a microcomputer.

FIG. 5 is an operation process diagram of the ice making machine.

FIG. 6 is an operation process diagram of the ice making machine.

FIG. 7 is an operation process diagram of the ice making machine.

[Explanation of symbols]

 I Ice machine 1 Cooler 1A Ice making room 2 Evaporation pipe 3 Fountain hole 5 Water tray 6 Water tank 9 Circulation pump 10 Reduction motor 12 Water supply solenoid valve 20 Controller 23 Hot gas solenoid valve 25 Microcomputer 36 Power frequency detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25C 1/22 F25C 1/04

Claims (2)

(57) [Claims] 1. A state in which a plurality of ice-making chambers that open downward are partitioned and formed, and a tiltable water tray that closes each ice-making chamber is provided, wherein the water tray is at a predetermined horizontal closed position. An ice making process in which water for ice making in a water tank is spouted from a fountain hole formed on the surface of the water tray by a circulation pump into each ice making chamber to make ice, and the cooler is operated in a state where the water tray is at a predetermined inclined open position. A water supply valve provided in a water supply path to the water tank, and control means for controlling the operation of the ice machine in the ice making process and the ice removing process. The control means starts the return movement of the water tray from the end of the deicing, opens the water supply valve before the water tray returns to the horizontal closed position, and controls the water tank. An ice machine characterized by starting water supply. 2. A state in which a cooler defining a plurality of ice-making chambers opened downward and a tiltable water tray closing each ice-making chamber is provided, and the water tray is in a predetermined horizontal closed position. An ice making process in which water for ice making in a water tank is spouted from a fountain hole formed on the surface of the water tray by a circulation pump into each ice making chamber to make ice, and the cooler is operated in a state where the water tray is at a predetermined inclined open position. A water supply valve provided in a water supply path to the water tank, and control means for controlling the operation of the ice machine in the ice making process and the ice removing process. Power frequency detecting means for detecting a power frequency and outputting a power frequency signal to the control means, wherein the control means starts the return of the water tray from the end of the deicing, and Based on the frequency signal, the water dish is An ice making machine characterized in that the water supply valve is opened a predetermined time before returning to the horizontal closed position, and water supply to the water tank is started.