JPH0451330Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to an automatic ice maker, and more specifically,
The present invention relates to an automatic ice-making machine equipped with a protection device that can effectively prevent a compressor from burning out or wasting power during ice-making operation.

BACKGROUND ART Automatic ice making machines for continuously producing large numbers of ice cubes, ice sheets, and other ice shapes of various shapes are suitably used depending on their purpose. For example, a large number of ice-making compartments defined in the ice-making compartment and open downwards are closed by a water tray so that they can be opened and closed, and ice-making water is injected from the water tray to gradually pour ice cubes into the ice-making compartments. A so-called closed cell type ice maker is designed to form ice cubes, and a so-called closed cell ice maker is designed to directly supply ice making water to a large number of ice cube chambers that open downward, without going through a water tray, and form ice cubes in the chambers. Open-cell type ice makers and ice-making machines with ice-making plates arranged at an angle and ice-making water flowing down to the front or back side of the ice-making plates to form ice sheets on the surface of the ice-making plates have become widely used. There is.

These automatic ice making machines generally include an ice making mechanism above the machine and a refrigeration system for cooling the ice making mechanism below the machine, and the refrigeration system includes a compressor, a condenser, a capillary reach tube, and an evaporator. It is composed of various parts such as vessels. The evaporator led out from this refrigeration system is disposed in the ice making section of the ice making mechanism and cools the ice making section. On the other hand, ice is generated by circulating and supplying ice-making water to the ice-making unit that is kept cooled, and when the ice-making completion detection device detects that the ice has grown to a predetermined size, the supply of ice-making water is stopped. . Then, by switching the valve body,
High-temperature refrigerant gas from the compressor is supplied to the evaporator via a bypass pipe to heat the ice making section, and the ice produced in the ice making section is allowed to fall under its own weight and collected and stored in a stocker located below. It's getting old. Note that a fin-and-tube type condenser is generally used in a refrigeration system, and the condenser is forcibly cooled by a cooling fan.

As protection devices for the refrigeration system during ice-making operation, a motor protector (overload protection device) disposed on the compressor, a pressure switch that detects the pressure of the refrigerant, etc. are generally used. In addition, some devices detect the condensation temperature of the refrigerant using a temperature sensing element such as a thermostat or thermistor and activate an alarm device.

Problems that the invention aims to solve In conventional automatic ice making machines, as described below,
Even if the protective device is activated for some reason during ice-making operation, there still remains the problem that the compressor and motor may burn out, and power consumption and ice-making water may be wasted. In other words, if the cooling fan motor of an air-cooled condenser becomes unable to rotate (so-called fan lock) due to damage to its bearings, the condensing capacity of the condenser will be significantly reduced, and the air will leak from the discharge side of the compressor in the refrigeration system. The refrigerant pressure in the high pressure circuit reaching the inlet side of the pillar reach tube increases. Moreover, the refrigerant pressure in the low pressure circuit extending from the outlet side of the capillary reach tube to the suction side of the compressor also increases. In this way, even though the amount of refrigerant circulating in the compressor increases, if forced air cooling of the compressor by the fan motor and cooling of the inside of the compressor by refrigerant gas are no longer performed, the compressor will be in an overload state. As a result, power consumption increases and the compressor becomes abnormally high temperature.

In this state, the motor protector, which is an overload protection device for the compressor, is activated and stops supplying electricity to the compressor. However, when the compressor stops, the refrigerant pressure in the refrigeration circuit gradually decreases, and the temperature of the compressor body also gradually decreases due to natural heat radiation. As a result, the motor protector automatically returns to resume energization of the compressor, thereby restarting overload operation of the compressor.
The motor protector then re-energizes and the compressor stops, repeating the cycle. In other words, when the fan is locked, the compressor will repeat the overload operation and stop unless the user notices the inability to make ice and turns off the power. This not only results in wasted power consumption, but also causes deterioration of the lubricating oil that forms an oil film on the rotating parts of the compressor. If the oil deteriorates in this way, it will impede the smooth operation of the sliding parts and cause further wear, which may cause the compressor itself to seize and become locked, or cause burnout of the motor.

Therefore, in order to prevent burnout of the compressor due to fan lock, conventionally a pressure switch is installed on the high pressure side of the refrigeration system, and when the pressure of the high pressure refrigerant rises below a predetermined value, the pressure switch responds to reduce the compression. The power to the machine is cut off.
However, this pressure switch is designed to operate before the aforementioned motor protector operates (the degree of overload applied to the compressor is reduced compared to when the switch is not provided), and the pressure Since the operating value of the switch is set to respond to a high pressure that does not operate under normal conditions, the compressor will still operate under overload when the fan is locked compared to normal operating conditions.

Furthermore, when the pressure switch operates and the compressor stops during the fan lock state, the refrigerant pressure decreases due to the cooling effect due to natural heat radiation, but when this decreases to a predetermined lower limit setting, the internal contact of the pressure switch turns on, Power to the compressor is restarted and overload operation of the compressor is restarted.
In other words, even if a pressure switch is installed, the degree of overload on the compressor will only be reduced compared to the case described above, but there will be no change in the fact that the compressor will repeatedly operate and stop overloaded, which is the basic problem. It's not a solution.

Therefore, a pressure switch with a locking function is used, and once the pressure switch is activated, it is held in that state to prevent the compressor from repeating overload operation and stop, and the reset is performed manually. An automatic ice maker configured as shown in FIG. Therefore, in general, a method is adopted in which a temperature detection device detects when the condensing temperature becomes abnormally high due to fan lock, and an alarm device is activated thereby to notify the user of the abnormality. However, if the user is not present, it is impossible to avoid repeated overload operation and stoppage of the compressor due to the action of the motor protector and pressure switch described above.

Repeated overload operation and stop of the compressor as described above not only causes fan lock, but also causes the heat exchange section of an air-cooled condenser to become dirty in layers with oil, dust, dirt, etc. This occurs because heat radiation is obstructed when it is blocked by paper scraps, etc. In the case of water-cooled condensers, this occurs when the water supply pressure decreases or there is a water outage.

In addition, in the case of a three-phase compressor, if a phase loss occurs for some reason and results in phase loss operation, the motor protector is activated due to overheating of the internal motor, causing the motor to turn on.
It will turn off repeatedly, causing wasted power consumption and burnout of the compressor, as described above.

If the compressor in the refrigeration system breaks down, it will no longer be possible to make ice, but drive parts such as the pump motor in the ice making water supply system and the condenser cooling fan motor will continue to operate, so even though ice making is not possible, there will be no electricity or ice making. Water will be wasted.

Failures in automatic ice making machines occur not only in the compressor as described above, but also in other parts, and it is necessary to provide protection against such failures. However, in the past, this type of protection device was not provided, resulting in the following problems.

If the solenoid valve that opens and closes the deicing bypass circuit in the refrigeration system fails and cannot be closed, high-temperature refrigerant will flow directly into the evaporator, making it impossible to make ice in the ice making section. In this case, if there is no protection device, other devices such as the pump motor will continue to operate.
This results in wasted electricity and ice making water.

If refrigerant gas leaks due to poor airtightness at connections in the pipes of the refrigeration system, the refrigeration capacity decreases and ice making becomes impossible. However, the compressor compresses the air flowing into the refrigeration system, and as cooling by the low-temperature refrigerant gas flowing into the compressor is cut off, the compressor motor coil overheats, which eventually causes the refrigeration oil to cool. Deterioration of the motor, wear of the sliding parts, and burnout of the motor coil occur in a short period of time. In this case, there is no pressure rise, so it cannot be protected by a pressure switch installed on the high pressure side, and
Since there was no refrigerant, the condensation temperature did not rise and the alarm system did not work.

If the water supply valve connected to the external water supply system of the ice making water supply system malfunctions and leaks water or becomes unable to close,
Since water continues to be supplied from the external water supply system, the temperature of the ice-making water cannot be lowered, making it impossible to make ice. In this case as well, since there is no conventional protection device, the ice maker continues to operate, wasting electricity and the like.

When the capillary reach tube becomes frozen due to moisture in the refrigeration system, and the capillary reach tube becomes blocked (moisture clogging), ice making becomes impossible because refrigerant is not supplied to the evaporator. In this case as well, conventionally, there is no protection device, so power and the like are wasted.

As mentioned above, various types of failures cause wastage of electricity and ice-making water, but in order to prevent these wastes, installing individual protection devices and detection devices to deal with each failure will reduce the overall cost of the ice-making machine. There is a problem with it being bulky.

Purpose of the invention The present invention was proposed in view of the problems inherent in the conventional automatic ice maker mentioned above, and was proposed to appropriately solve these problems. To provide an automatic ice making machine capable of preventing waste and saving water, and equipped with an inexpensive protection device.

Means for Solving the Problems In order to overcome the above-mentioned problems and achieve the intended purpose, the present invention provides an ice-making section equipped with an evaporator connected to the refrigeration system, and an ice-making water supply to the ice-making section. An automatic ice making machine comprising an ice making water supply system, a device for deicing ice generated in the ice making section, and a temperature detection device for detecting the temperature of ice making water circulating through the ice making water supply system. The present invention is characterized in that a protection device is provided that stops the ice-making operation if the temperature of the ice-making water does not fall below a predetermined temperature within a predetermined time after the start.

Operation If the fan locks or other malfunction occurs, it will be impossible to make ice. Therefore, by detecting the inability to make ice, it is possible to know that some kind of failure has occurred.
In the present invention, when it is detected that the temperature of the ice making water does not fall below a predetermined temperature within a predetermined time after the start of ice making, it is determined that ice making is no longer possible, and the protection device stops the ice making operation.

Embodiments Next, the automatic ice making machine according to the present invention will be described below with reference to preferred embodiments and the accompanying drawings.

FIG. 1 shows an example of an automatic ice maker in which the present invention is suitably implemented. This automatic ice-making machine includes an ice-making chamber 1 defining a large number of ice-making compartments 2 that open downward, and an evaporator 3 connected to a refrigeration system is disposed on the outer upper surface of the ice-making chamber 1. Further, a water tray 4 is tiltably disposed below the ice-making chamber 1, and normally closes the ice-making chamber 2 horizontally from below. The water tray 4 is pivotally supported at one end by a pivot (not shown), and is forcibly tilted by an actuator to open the ice making chamber 2 during deicing operation. A distribution pipe 6 for supplying ice-making water to each ice-making compartment 2 is provided on the lower surface of the water tray 4, and an ice-making water tank 5 is further provided below the water tray 4. This tank 5 stores the required amount of ice-making water necessary for one ice-making cycle through the external water supply system 10.
The water is supplied through the water supply valve WV.

The water in the ice-making water tank 5 is sent from the bottom to the distribution pipe 6 via the water supply pipe 11 and the pipe PM, and from the numerous fountain holes 7 formed in the water tray 4 corresponding to each of the ice-making compartments 2. It is injected into the ice making compartment 2. A part of this ice-making water freezes on the inner wall surface of each ice-making compartment 2, and the water that has not yet frozen is left in the water tray 4.
The ice water is then returned to the ice-making water tank 5 through a drainage hole 9 formed adjacent to the fountain hole 7. By circulating ice-making water through the ice-making water supply system 8 having this configuration, ice is gradually grown in layers within the ice-making chamber 1.

On the outer surface of the ice-making compartment 1, there is a temperature detection device consisting of a temperature sensing element such as a thermostat or a thermistor.
Th ₂ is closely placed. This temperature sensing device
Th ₂ is for detecting the temperature of the ice making compartment 1,
When ice has grown sufficiently in the ice-making compartment 2 and the temperature of the ice-making compartment 1 has decreased, the temperature detection device _Th2 is activated to end the ice-making operation and shift to the de-icing operation.

When the automatic ice maker shown in FIG. 1 shifts to deicing operation, it stops the pump PM to stop the supply of ice making water, and moves the water tray 4 and ice making water tank 5 to a certain angle under the action of an actuator (not shown). It is tilted to drain all the ice-making water remaining in the ice-making water supply system 8. Also, by switching the valve body, hot gas is supplied to the evaporator 3 connected to the refrigeration system to warm the ice making compartment 1, causing the ice in the ice making compartment 2 to fall under its own weight and guided into the ice storage 13. discharge.

Completion of the ice falling into the ice storage 13 is detected by a temperature detection device _Th3 , which is arranged closely on the side of the ice making chamber 1 and is made up of, for example, a thermostat or a thermistor, by detecting a temperature rise in the ice making chamber 1. . After the completion of ice falling is detected, the actuator is reversed, the water tray 4 and the ice-making water tank 5 are returned to their original horizontal positions, the ice-making chamber 2 is closed from below, and water is supplied from the external water system 10 via the water supply valve WV. ice-making water is supplied to the ice-making water tank 5. Also, ice-making water is supplied to the ice-making chamber 1 by the pump PM, and ice-making is started again.

In this embodiment, a temperature sensing device _Th4 consisting of a temperature sensing element such as a thermostat or a thermistor is used.
is arranged in the ice-making water tank 5, and the ice-making water tank 5
The temperature of the ice-making water stored inside is detected by this temperature detection device Th ₄ . The temperature detection device _Th4 may be disposed at any position as long as it can accurately detect the temperature of the ice-making water, and is not limited to the illustrated embodiment.

In addition, the code Th ₁ in FIG. 1 indicates the ice storage 13.
When there is no more ice in the ice storage 13, the switch _Th1 closes and starts the ice making operation, and when a predetermined amount of ice is stored in the ice storage 13, it opens. This will stop the ice maker.

FIG. 2 shows a schematic configuration of the refrigeration system. The refrigerant gas compressed by the compressor 20 is condensed and liquefied by the condenser 21, dehumidified by the dryer 22, and then decompressed by the capillary reach tube 23.
Freezing is performed in each ice making compartment 2 by evaporating in the evaporator 3 disposed on the outer upper surface of the ice making compartment 1 and exchanging heat with ice making water supplied from a fountain into each ice making compartment 2. . The refrigerant that has evaporated and vaporized in the evaporator 3 and the liquid refrigerant that has not been completely evaporated flow into the accumulator 24 in a gas-liquid mixed phase state, where the gas-phase refrigerant and liquid-phase refrigerant are separated, and the gas-phase refrigerant is passed through the suction pipe. The liquid refrigerant is returned to the compressor 20 via the refrigerant 25 and stored in the accumulator 24. In addition, the symbols in Figure 2
FM indicates a fan motor for the condenser 21.

Further, a hot gas pipe 26 branched from the discharge side of the compressor 20 is connected to the evaporator 3 via a hot gas valve HV.
The high-temperature refrigerant discharged from the compressor 20 during deicing flows into the evaporator 3 from the hot gas pipe 26 through the hot gas valve HV, warms the ice making chamber 1, and flows into each ice making compartment 2. The surrounding surface of the generated ice blocks is heated, and each ice block is caused to fall under its own weight.
The high-temperature refrigerant flowing out of the evaporator 3 flows into the accumulator 24, heats and evaporates the liquid phase refrigerant staying in the accumulator 24, and returns it to the compressor 20 from the suction pipe 25 as a gas phase refrigerant.

FIG. 3 shows an example of the electric control circuit of the automatic ice maker according to this embodiment. In this figure, a fuse F is provided between the power supply line A and the connection point D, and the connection Point D and power supply line B
Between the opening and closing contacts of the timer device T, which will be described later,
T ₁ , temperature detection device Th ₄ , relay X, and return push button PB are connected in series, and _the connection point between temperature detection device Th ₄ and relay
It is connected to connection point D via. The temperature detection device _Th4 operates to open the contact when the temperature of the ice-making water is below a predetermined temperature t, and close the contact when the temperature exceeds the predetermined temperature. In this embodiment, a timer device T, a temperature detection device Th ₄ , and a relay X constitute a protection device.

Between the connection point D and the connection point H, the normally closed contact _X2 of the relay X and the ice storage detection switch _Th1 are connected in series, and the compressor CM is connected between the connection point H and the power supply line B. The movable contact a of the changeover switch _S1 that tilts the water tray 4 during the deicing operation of the ice making compartment 1 described above is connected to the connection point H, and the fixed contact b of the changeover switch _S1 is connected to the movable contact of the temperature detection device _Th2 . It is connected to contact e. Fixed contact f of temperature detection device Th ₂
A cooling fan motor FM for the condenser 21, a pump motor PM for ice-making water circulation, and the timer device T are connected in parallel between and the power supply line B. This timer device T is for fan motor FM
After a predetermined time has elapsed since the start of operation of the pump motor PM and the pump motor PM (start of ice making operation), the contact _T1 is closed for a predetermined time _T0 .

The fixed contact g of the temperature detection device _Th2 is connected to the power terminal m for driving the actuator motor AM in the tilting direction for tilting and returning the water tray 4, etc., and the other power terminal k of the actuator motor AM is Connected to power supply line B. changeover switch
The fixed contact c of _S1 and the power supply terminal n for driving the actuator motor AM in the return direction are connected to a temperature detection device.
_A hot gas valve HV and a water supply valve are connected between the fixed contact c and the power supply line B.
WV is connected in parallel.

Next, the operation of the automatic ice maker having the above-mentioned configuration will be explained with reference to the timing chart shown in FIG. First, the automatic ice maker is powered on (the power switch is not shown). At this time, there is no ice in the ice storage, so the temperature detection device Th ₁ is closed. The movable contact a of the changeover switch _S1 is connected to the fixed contact b, and since the temperature of the ice making chamber 1 is about room temperature, the movable contact e of the temperature detection device _Th2 is connected to the fixed contact b.
is connected to the fixed contact f. Therefore, at the same time as the power is turned on, the compressor (CM) 20 and fan motor
Power is started to be applied to the FM, pump motor PM, and timer device T, and ice-making operation begins. This results in
The circulation of the refrigerant and the circulation of the ice-making water explained in connection with FIG. 1 and FIG.
The temperature will gradually decrease. When the ice-making operation is normal, the ice-making water temperature becomes 0° C. after the required time has elapsed from the start of ice-making. In addition, the abnormal setting temperature t of the temperature detection device Th ₄ is set to a temperature higher than 0°C, and the setting time of the timer device T is set to be longer than the time required for the ice making water temperature to reach 0°C from the start of ice making. There is. When the ice-making water temperature (the temperature of the ice-making chamber 1) falls below t, the temperature detection device _Th4 is opened, and when the ice-making water temperature reaches 0°C, ice begins to grow.

When the timer device T, which has been measuring time since the start of ice making, times out its set time, the timer device T closes the contact _T1 for a predetermined time _T0 , and then opens the contact _T1. . However, at this time, since the temperature sensing device _Th4 is open, relay X is not energized by the closing of contact _T1 , and its normally closed contact _X2 remains closed. .

When ice making is completed, the temperature detection device Th ₂ detects this and changes the connection of the movable contact e to the fixed contact g, and the power to the fan motor FM, pump motor PM, and timer device T is stopped, and the actuator Motor AM is energized and deicing operation begins.
When the water tray 4 and the ice-making water tank 5 are fully tilted by the rotation of the actuator motor AM, the movable contact a of the changeover switch _S1 is switched to the fixed contact c. At this time, the temperature detection device _Th3 is in an open state. By changing the connection of the changeover switch _S1 , the water supply valve WV is opened, and new high-temperature ice-making water is supplied from the external water supply system to the tank 5, and the evaporator 3 is warmed by opening the hot gas valve HV. de-icing is facilitated. As mentioned above, when the ice in the ice making chamber 2 falls due to its own weight and the temperature rises further, the temperature detection device Th ₃ detects that deicing is complete.
Temperature sensing device Th ₃ is closed. At this time, the temperature detection device Th ₄ is in a closed state because the ice making water temperature is higher than t, and the movable contact e of the temperature detection device Th ₂ is reconnected to the fixed contact f. When the actuator motor AM is energized by closing the temperature detection device _Th3 , the motor AM reversely rotates to return the water tray 4, etc. to the horizontal state, and upon completion of the return operation, the changeover switch _S1 is moved. Contact a is reconnected to fixed contact b. As a result, the ice-making operation is started again, and the above-described operation is repeated.

If there is a decrease in condensing capacity due to fan lock or clogging of the condenser as mentioned above, a decrease in water supply pressure or water outage in the water-cooled condenser, open-phase operation in the three-phase compressor, leakage of refrigerant gas, or failure of the compressor, If any one of the following occurs: a malfunction, a hot gas valve closing failure, water clogging in the refrigeration system, etc., the refrigeration capacity will be extremely reduced and the temperature of the ice making chamber 1 will not drop during ice making operation. Therefore, the temperature of the ice-making water will not drop, and even if the ice-making operation is started, the temperature of the ice-making water will not fall below the abnormal setting temperature t, and the temperature detection device _Th4 will remain closed. Then, the timer device T times out the set time and the contact _T1
At the moment of closing, power supply line A → Fuse F → Connection point D → Contact T ₁ → Temperature detection device Th ₄ → Relay X → Return push button PB → Power supply line B
The circuit leading to is closed and current flows through relay X. As a result, the normally open contact X ₁ of the relay X is closed, and the normally closed contact X ₂ is opened. By closing the normally open contact _X1 , the relay X is self-held, and by opening the normally closed contact _X2 , the power to the compressor CM, fan motor FM, and pump motor PM is cut off. Therefore, in the automatic ice maker according to this embodiment, there is no need for repeated overload operation and stop of the compressor, which was a problem in the conventional technology, and it is possible to avoid compressor failure, prevent wasted power consumption, and save water. This can be done effectively. If a warning lamp L is connected in parallel with the relay X as shown by the broken line in FIG. 3, the user can be visually notified of the occurrence of a problem such as fan lock or clogging. Further, an alarm means such as a buzzer may be provided in parallel with this, and may be operated simultaneously with the alarm lamp L, so that the user is audibly alerted to the trouble.

If you want to start ice making again after fixing problems such as fan lock or condenser clogging, press return pushbutton PB and release its contacts to release the self-holding of relay The self-holding of relay X is released by cutting it off.

Although the automatic ice making machine according to the preferred embodiment of the present invention has been described below, the present invention is not limited to the ice making method of the embodiment, and the present invention is not limited to the ice making method of the embodiment.
It can be applied to ice making machines that employ any type of ice making method, such as a plate type, flowing type, or water storage type. In addition, as a means of detecting the completion of ice making, the temperature detection type (temperature detection device Th ₂ ) was used as an example, but there are also timer type, water level detection type, pressure detection type, ice thickness detection type, and temperature + timer type. The present invention can be applied to any type of ice making machine, such as the water level + timer type, etc.

Furthermore, in the above-mentioned embodiment, the relay It is also possible to configure a protection device that stops the ice-making operation if the temperature of the ice-making water does not fall below a predetermined temperature within a predetermined time after the start.

Effects of the invention As explained above, according to the automatic ice maker according to the invention, if the temperature of the ice making water does not fall below a predetermined time within a predetermined time after ice making starts, an abnormality is determined and the ice making operation is started. A protective device has been installed to prevent the condensing capacity from decreasing due to fan lock or condenser clogging, water supply pressure drop or water outage at the water-cooled condenser, open-phase operation at the three-phase compressor, refrigerant gas leaks, etc.
Even if an abnormality occurs such as a compressor failure, hot gas valve closing failure, or water clogging in the refrigeration system, the ice maker will surely stop. Therefore, it is possible to prevent wasted power consumption, save water, and avoid fatal failures of the compressor. Furthermore, since there is no need to provide dedicated protection devices for each abnormal state, manufacturing is possible at low cost, and maintenance is also facilitated.

[Brief explanation of the drawing]

The drawings show a preferred embodiment of the automatic ice maker according to the present invention, in which FIG. 1 is a schematic diagram of the ice making section and ice making water tank portion of the automatic ice maker according to the embodiment, and FIG. 2 is a diagram illustrating the implementation. FIG. 3 is a refrigeration system diagram of the automatic ice maker according to the example, FIG. 3 is an electric control circuit diagram of the automatic ice maker according to the example, and FIG. 4 is a timing chart explaining the operation of the automatic ice maker according to the example. 1...Ice making compartment, 2...Ice making compartment, 3...Evaporator, 4...Water tray, 5...Ice making water tank, 20...
Compressor (CM), 21... Condenser, 23... Capillary reach tube, 24... Accumulator, 2
6... Hot gas pipe, Th ₁ , Th ₂ , Th ₃ , Th ₄ ...
...Temperature detection device, X... Relay, X ₁ ... Normally open contact of relay X, X ₂ ... Normally closed contact of relay X, T
...Timer device, T ₁ ...Opening/closing contact of timer device,
FM...Fan motor, PM...Pump motor,
WV...Water supply valve, HV...Hot gas valve.

Claims (1)

[Scope of Claim for Utility Model Registration] [1] An ice making section that is connected to a refrigeration system and is provided with an evaporator, an ice making water supply system that supplies ice making water to the ice making section, and an ice making section that supplies ice produced in the ice making section. In an automatic ice maker equipped with a device for deicing and a temperature detection device for detecting the temperature of the ice making water circulating through the ice making water supply system, the temperature of the ice making water falls below a predetermined temperature within a predetermined time after the start of ice making. An automatic ice-making machine characterized by being equipped with a protection device that stops the ice-making operation if the ice-making operation does not decrease. [2] The automatic ice making machine according to claim 1, wherein the protection device includes an alarm means that is activated during a protection operation that stops the ice making operation. [3] The automatic ice-making machine according to claim 1, wherein the protection device includes a means for manually releasing the protection operation that stops the ice-making operation.