JP2013217555A - Method for operating automatic ice maker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a concern or emergency stop of a compressor by reducing load applied to the compressor even in an initial operation.SOLUTION: In an initial operation of an automatic ice maker, a compressor CM is activated, and deice operation is started when pressure of refrigerant in a high pressure side and in a low pressure side is balanced in the compressor CM by opening a hot gas valve HV during a protecting time of the compressor CM. The hot gas valve HV left opened is closed, and the closing of the hot gas valve HV is continued for a while directly after activation of the compressor CM during the deice operation.

Description

  The present invention relates to a method of operating an automatic ice maker that can reduce a load applied to a compressor at the time of start-up when the automatic ice maker is operated for the first time or when the operation is stopped for a long time and then the ice making operation is started again. Is.

  Spray-type automatic ice makers that continuously produce ice blocks by spraying ice-making water from below into a large number of ice-making chambers that open downward are suitable for use in facilities such as coffee shops and restaurants, and other kitchens. . As shown in FIG. 7, the ice making mechanism 10 of the automatic ice making machine has an ice making chamber (ice making unit) 12 horizontally arranged in the main body, and a large number of ice making chambers 12a that open downward are defined in a grid pattern. Yes. An evaporator 14 meanders on the top surface of the ice making chamber 12, and the evaporator 14 includes a compressor CM, a condenser CD, an expansion means EV, a cooling fan motor FM for cooling the condenser, and the like. 24. Further, immediately below the ice making chamber 12, a water dish 16 is pivotally supported via a support shaft 16 a, and an ice making water tank 18 is integrally provided below the water dish 16.

  In the ice making mechanism 10, when the ice making operation is started with the ice making chamber 12 a closed from below by the water dish 16, the vaporized refrigerant is circulated and supplied from the refrigeration circuit 24 to the evaporator 14 via the expansion means EV. The ice making chamber 12a is forcibly cooled and ice making water in the ice making water tank 18 is sprayed and supplied from the water dish 16 to the ice making chamber 12a by a pump motor 19 provided in the ice making water tank 18. Thereby, ice blocks M are gradually generated in the ice making chamber 12a. When the temperature detecting means TH disposed in the ice making chamber 12 detects the formation of the ice mass M, the ice making operation is shifted to the deicing operation, and the normally closed hot gas valve HV is opened to open the evaporator 14. Then, hot gas is supplied through the bypass circuit 26 to heat the ice making chamber 12. Further, the water tray opening / closing motor AM is driven to tilt the water tray 16 obliquely downward about the support shaft 16a, thereby opening the ice making chamber 12a. In this deicing operation, the ice making chamber 12 is heated by hot gas, and the icing portion between the ice making chamber 12a and the ice block M is melted. Then, the ice mass M separates and falls from the ice making chamber 12a by its own weight, slides down on the water dish 16 opened obliquely, and is stored in the stocker 22. The stocker 22 is provided with an ice storage switch SW for detecting full ice. When the ice storage switch SW enters a detection state, the ice making cycle for repeating the ice making operation and the deicing operation is stopped. When the ice block M in the stocker 22 is reduced and the ice storage switch SW is in a non-detection state, the ice making cycle is resumed. The completion of detachment of the ice block M from the ice making chamber 12 is detected by the temperature detecting means TH, whereby the deicing operation is shifted to the ice making operation, and the water tray opening / closing motor AM is reversely driven to reopen the water tray 16 again. Return to the closed position.

  For example, as an ice making device that performs deicing with hot gas, a pair of hot gas valves are inserted in parallel with a bypass circuit that supplies hot gas to the evaporator, and one of the hot gas valves is opened at the start of deicing operation, A small amount of hot gas is supplied to the evaporator to melt the frozen part of the water dish and ice block, and then the other hot gas valve is opened after a lapse of time to supply a large amount of hot gas to the evaporator. There has been proposed a structure in which an icing portion between the ice and the ice block is melted (see Patent Document 1).

JP 61-8579 A

  In the above-described automatic ice maker, when the operation is started, the compressor CM is activated to circulate the refrigerant in the refrigeration circuit 24. In order to reduce the load on the compressor CM at the time of start-up, as shown in FIG. 8 (1), a certain protection time is given to the compressor CM so that it does not start immediately after the power is turned on. Also, during the protection time, the hot gas valve HV is opened to achieve a pressure balance between the high pressure side and the low pressure side of the refrigerant in the compressor CM, and after this is substantially achieved, the compressor CM is started. Yes. It should be noted that ice blocks may remain in the water tray 16 during the previous deicing operation. In this case, if the ice making machine is started and immediately shifted to the ice making operation, there is a possibility that the water tray 16 that returns from the tilting posture to the horizontal posture may bite the remaining ice block with the ice making chamber 12. is there.

  In order to avoid such ice biting, a mode is set in advance to enter the deicing operation first when the ice making machine is started. When the compressor CM is started, the temperature detecting means TH monitors the temperature of the ice making chamber 12 and detects that the rising temperature of the ice making chamber 12 has reached a certain set value (for example, 10 ° C.). The valve HV is closed, the water tray opening / closing motor AM is driven, the water tray 16 is returned to the closed position, and the ice making operation is controlled.

  By the way, when the automatic ice maker shipped from the factory is operated for the first time after being installed in a kitchen or when the power is turned on again after the ice making operation is stopped for a long time, the ice storage switch SW is set to the full state of the stocker 22. In the case where the ice making switch is turned off after the ice making machine is stopped for a long time while the power is on and the ice making switch is turned off to restart the ice making cycle (hereinafter referred to as “initial operation”), the compressor CM is turned on. If the hot gas valve HV is opened during the protection time, a large load is applied to the compressor CM after startup. That is, due to the refrigerant pressure equilibrium due to the opening of the hot gas valve HV, the low-pressure side pressure of the compressor CM increases as shown in FIG. During the deicing operation, the pressure on the low pressure side continues to rise, and the pressure on the high pressure side gradually increases. In this state, when the ice making operation is started and the injection of ice making water into the ice making chamber 12 is started, the pressure on the low pressure side and the high pressure side of the compressor CM is considerably high. Excessive mechanical load is applied to the piston, and the load on the compressor motor increases.

  If such an overload operation is continued, heat exchange is performed between the ice making water already circulated and supplied to the ice making chamber 12 and the ice making chamber 12 in the ice making operation. Temperature rises. That is, as shown in FIG. 8 (2), the low-pressure side pressure of the refrigerant in the compressor CM further increases gradually, so that the load applied to the drive motor of the compressor CM also increases thereafter. In some cases, the compressor CM may be brought to an emergency stop as the load increases. This is an event that should be avoided. In the case of a refrigerator, such a problem does not occur because the object to be cooled is not water but air and the heat capacity load is small.

  Therefore, in order to prevent the above inconvenience, it can be considered that the torque of the drive motor in the compressor CM is increased to overcome the peak load. However, in this case, it is necessary to adopt a drive motor having a large capacity, which causes inconveniences such as an increase in the unit price of the compressor CM and an increase in power consumption.

  Therefore, the present invention has been proposed in order to suitably solve this problem in view of the problems inherent in the initial operation of the conventional automatic ice making machine. That is, an object of the present invention is to provide a compressor that can be used in an initial operation of an automatic ice maker even when the refrigerant temperature in the refrigeration circuit rises due to relatively high temperature ice making water circulated and supplied to the ice making chamber. An object of the present invention is to provide an operation method that prevents an increase in the low-pressure side pressure and thereby reduces the load applied to the compressor, thereby eliminating the possibility of an emergency stop.

In order to overcome the above-mentioned problems and achieve the intended purpose, an operation method of the automatic ice making machine according to claim 1 of the present application is
During ice making operation, refrigerant is supplied from the compressor to the evaporator through the condenser and expansion means, and ice making water is supplied to the ice making section cooled by the evaporator to generate ice blocks. , During the initial operation of an automatic ice maker that supplies hot gas from the compressor to the evaporator via a hot gas valve and causes the ice making unit to detach from the ice making unit by heating the evaporator, In the operation method of providing a protection time before, starting the deicing operation by starting the compressor by the passage of the protection time,
The hot gas valve is opened during the protection time of the compressor, and when the refrigerant pressures on the high pressure side and the low pressure side of the compressor are substantially balanced, the compressor is started and the deicing operation is started. ,
The gist of the invention is that the hot gas valve being opened is closed, and that the hot gas valve is kept closed for a while immediately after the start of the compressor during the deicing operation.
According to the first aspect of the present invention, since the hot gas valve is kept closed for a while immediately after the compressor is started, the pressure on the low pressure side of the refrigerant in the compressor is reduced. For this reason, the load on the compressor is reduced and the load peak after startup can be easily overcome. In addition, the ice making water is not supplied to the ice making part in the deicing operation, and the refrigerant supplied to the evaporator during the closing of the hot gas valve is easily returned to the compressor, and the compressor by the returning refrigerant is used. Since the temperature rise is also small, the operating load of the compressor can be reduced.

The gist of the invention according to claim 2 is that the hot gas valve being opened is closed after the compressor is started, and then opened during the deicing operation.
According to the invention which concerns on Claim 2, the pressure of the low voltage | pressure side of the refrigerant | coolant in a compressor can be reduced after starting of a compressor.

The gist of the invention according to claim 3 is that the open hot gas valve is closed simultaneously with the start of the compressor and then opened during the deicing operation.
According to the invention of claim 3, since the hot gas valve is closed simultaneously with the start of the compressor, the pressure on the low pressure side of the compressor does not increase when the compressor is started, and the load on the compressor Can be further reduced.

The gist of the invention according to claim 4 is that the hot gas valve being opened is closed during a protection time of the compressor and then opened during the deicing operation.
According to the invention of claim 4, since the hot gas valve is closed before the compressor is started, there is no refrigerant flow due to pressure equilibrium when the compressor is started, and the compressor at the time of start-up Thus, an excessive load is not applied to the compressor, and the stability of the compressor is increased.

  According to the operation method of the automatic ice maker according to the present invention, the load applied to the compressor is also applied during the so-called initial operation of operating the ice maker for the first time or restarting the ice maker after a relatively long shutdown period. The risk of an emergency stop of the compressor can be avoided. Therefore, excessive torque is not applied to the motor that drives the compressor, power consumption can be reduced, and dangers such as motor burnout can be eliminated. Furthermore, since it becomes possible to set the capacity | capacitance and specification of the motor which drive a compressor low, the cost which this motor requires can be reduced.

(1) is a timing chart during the initial operation of the injection type ice making machine according to the first embodiment, and (2) is a diagram showing changes over time in the high pressure side and the low pressure side of the refrigerant. It is a flowchart figure which shows the driving | operation procedure at the time of the initial stage driving | operation of the compressor and hot gas valve in the injection type ice making machine of Example 1. FIG. (1) is a timing chart during the initial operation of the injection type ice making machine according to the second embodiment, and (2) is a diagram showing changes over time in the refrigerant on the high-pressure side and the low-pressure side. It is a flowchart figure which shows the driving | operation procedure at the time of the initial stage driving | operation of the compressor and hot gas valve in the injection type ice maker of Example 2. FIG. (1) is a timing chart during the initial operation of the injection type ice making machine according to the third embodiment, and (2) is a diagram showing changes over time in the high-pressure side and the low-pressure side of the refrigerant. It is a flowchart figure which shows the driving | operation procedure at the time of the initial stage driving | operation of the compressor and hot gas valve in the injection type ice maker of Example 3. FIG. It is explanatory drawing which shows roughly the ice making mechanism and refrigeration circuit of the injection type ice making machine which concern on an Example. (1) is a timing chart at the time of initial operation of the injection type ice making machine according to the prior art, and (2) is a diagram showing a change with time of the high pressure side and the low pressure side of the refrigerant.

  Next, the operation method of the automatic ice making machine according to the present invention will be described below with reference to the accompanying drawings by giving a preferred embodiment. In the embodiment, the ice making water is sprayed and supplied to the ice making chamber from below, and the water tray is tilted downward when deicing, but the ice making method is not limited to this. Absent. For example, it may be a flow-down type ice maker that circulates and supplies ice making water from above to an ice making plate arranged upright or inclined, and generates ice plate or crescent ice.

  The outline of the injection type ice making machine in which the operation method of the automatic ice making machine according to the present invention is implemented has been described with reference to FIG. The operation method of the present invention is implemented in the case of the initial operation of the ice making machine described above. In other words, when an automatic ice maker that has been tested and packed at the factory is turned on for the first time after being installed in a restaurant, etc., or for some reason, the power is turned on after a certain amount of time has passed since the previous ice making operation. In this case, the case where the ice making cycle is resumed after the ice making cycle has been stopped for a long time while the power is turned on is detected. In such an initial operation, when turning on the power of the ice making machine or restarting the operation, the compressor is driven after the protection time of the compressor has elapsed, or the ice removing operation is started first. It is also as described above.

  The present invention preferably performs control to open the hot gas valve of the refrigeration circuit before the compressor protection time elapses and then close the hot gas valve at a required timing after the initial operation. This prevents an excessive load from being applied to the compressor. In the present invention, three examples of the timing for opening and closing the hot gas valve are conceivable, so each example will be described over time.

  In the jet ice maker shown in FIG. 7, it is assumed that the power is turned on to execute the initial operation. At this time, as shown in the timing chart of FIG. 1 (1), the compressor CM is set with a protection time to be delayed by a timer, for example, so that the drive of the compressor CM is cut off (OFF). The hot gas valve HV in the refrigeration circuit 24 is closed (OFF), and the cooling fan motor FM of the condenser CD is also stopped (OFF). Further, the water tray opening / closing motor AM stops (OFF) the water tray 16 at a raised position where the ice making chamber 12 is closed from below.

  The operation over time after power-on will be described with reference to the flowchart of FIG. When the power is turned on in step S1 to start the ice making machine, the protection time of the compressor CM starts in step S2. Since the hot gas valve HV being closed is set to open for 2 minutes 30 seconds after the power is turned on, for example, after entering the protection time of the compressor CM, the hot gas valve HV is set in step S3. It is confirmed whether or not a predetermined set time has elapsed. If the result is affirmative (YES), the process proceeds to step S4 to open the hot gas valve HV.

  By opening the hot gas valve HV, as shown in FIG. 1 (2), the high-pressure side of the refrigerant in the compressor CM is lowered, and the low-pressure side is raised so that the pressures of both are substantially balanced. The compressor CM protection time is set as a delay time of 3 minutes, for example, with a timer. Therefore, in step S5, it is confirmed whether or not the compressor CM protection time has elapsed. In step S6, the compressor CM is started, and the water tray opening / closing motor AM is driven to lower the water tray 16 from the ice making chamber 12, thereby starting the deicing operation.

  After the ice making machine enters the deicing operation in this way, whether or not a certain time (for example, about several seconds to 10 seconds after the deicing operation is started) has elapsed after the hot gas valve HV is opened in the next step S7. If the result is affirmative (YES), the process proceeds to step S8 to close the hot gas valve HV. At this time, as shown in FIG. 1 (2), the high pressure Pd, which has been lowered due to the pressure equilibrium, slightly rises by driving the compressor CM, and the low pressure Ps, which has been raised due to the pressure equilibrium, also slightly rises. However, this is not so much as to put a burden on the compressor CM. Next, in step S9, it is confirmed whether or not a certain time (for example, several seconds to 30 seconds) has elapsed after the hot gas valve HV is closed, and if affirmative (YES), the hot gas valve HV is opened in step S10. To do. That is, the hot gas valve HV is kept closed for a while after the compressor CM is started.

  The behavior of the refrigerant while the hot gas valve HV from step S8 to step S10 is closed is shown in FIG. That is, during this time, the high pressure Pd further increases, but the evaporator 14 is cooled by the operation of the compressor CM, so that the pressure decreases. Further, the low pressure Ps is lowered by the operation of the compressor CM. The index for controlling the opening and closing of the hot gas valve HV is not limited to the elapse of the predetermined time described above, but the temperature of the ice making chamber 12 is detected and the temperature of the ice making chamber 12 is set to a predetermined value (for example, 0 ° C.) It is good also as a control parameter | index. Further, as a control index for opening and closing the hot gas valve HV, a pressure sensor is provided in the low-pressure refrigerant line of the compressor CM, thereby detecting that the low-pressure Ps of the compressor CM has dropped to a predetermined value, Furthermore, a temperature sensor may be provided in the low-pressure side refrigerant pipe of the compressor CM so as to detect that the refrigerant temperature has dropped to a predetermined value.

  By opening the hot gas valve HV in step S10, the evaporator 14 is directly supplied with hot gas from the compressor CM and heated. The temperature detector TH monitors the temperature rise of the evaporator 14, and when it has detected that the required set temperature has been reached, the hot gas valve HV is closed. That is, in step S11, it is confirmed whether the evaporator 14 has reached a required set temperature. If the result is affirmative (YES), the process proceeds to step S12, and the hot gas valve HV is closed. At the same time, the water tray opening / closing motor AM is driven to raise the water tray 16 and the cooling fan motor FM of the condenser CD is rotationally driven. Thereby, the ice making operation of step S13 is started. Simultaneously with the start of the ice making operation, the pump motor 19 is driven to supply ice making water to the ice making chamber 12. Note that the determination index in step S11 may be detection of completion of deicing by integrating the exchange heat amount in the evaporator 14.

  As described above, in the present invention according to the first embodiment, as shown in FIGS. 1 (1) and (2), the hot gas valve HV is closed for a short time immediately after the start of the compressor CM. The pressure on the low pressure side in CM decreases. For this reason, conventionally, the phenomenon that the pressure on the low pressure side of the compressor CM is increased and an overload is applied to the compressor drive motor is eliminated, the load on the compressor CM is reduced, and the load after the start-up is started. You can easily get over the peak. In addition, since the ice making water to be cooled has not yet been injected into the ice making chamber 12, the refrigerant in the refrigeration circuit 24 easily returns to the compressor CM. Further, since the heat exchange of the refrigerant in the evaporator 14 is not active, the temperature rise of the compressor CM is slightly reduced by the refrigerant returning to the compressor CM, and the load in the ice making operation is reduced as a whole. Even if ice blocks may remain in the ice making chamber 12, the temperature of the ice making chamber 12 is sufficiently lowered because the ice blocks have a negative temperature. Therefore, the refrigerant is easily returned to the compressor CM as in the case described above.

  Next, a second embodiment of the present invention will be described. In the invention of the first embodiment described above, the operation control for opening the hot gas valve HV during the protection time of the compressor CM and closing the hot gas valve HV after a while after the compressor CM is started. It was something to do. On the other hand, in the invention of the second embodiment, as shown in FIG. 3 (1), the hot gas is generated at the same timing as the protection time of the compressor CM is over, the compressor CM is started, and the deicing operation is started. Control to close the valve HV is performed. FIG. 4 shows a control flow of the hot gas valve HV in the second embodiment, and only the part surrounded by the one-dot chain line is different from the control flow of FIG. That is, it is confirmed in step S5 whether or not the protection time of the compressor CM has elapsed. If the determination is affirmative (YES), the process proceeds to step S6 to start the compressor CM and start the deicing operation. To close the hot gas valve HV. Next, in step S8, it is confirmed whether a predetermined time has elapsed since the hot gas valve HV was closed. If the result is affirmative (YES), the hot gas valve HV is opened in step S9.

  At this time, the low pressure Ps of the refrigerant can be further reduced as compared with the case of the first embodiment, as can be seen from the comparison between FIG. 3 (2) of the second embodiment and FIG. 1 (2) of the first embodiment. . This is because the hot gas valve HV is opened until the compressor CM is started, so that the low pressure Ps of the refrigerant immediately after the start of the compressor CM does not increase. Thereby, even after the deicing operation is started, the low pressure Ps can be kept low, and the load on the compressor CM when entering the ice making operation can be further reduced.

  Furthermore, Embodiment 3 of the present invention will be described with reference to FIGS. In this embodiment, the opening timing of the hot gas valve HV during the protection time of the compressor CM is set about 30 seconds ahead of the other embodiments to accelerate the refrigerant pressure equilibrium in the compressor CM. It is. Further, during the protection time, the open hot gas valve HV is closed after a predetermined time has elapsed. This is to prevent the refrigerant from flowing into the refrigeration circuit 24 when the compressor CM is started, thereby facilitating and stabilizing the compressor CM.

  FIG. 6 is a control flow of the hot gas valve HV in the third embodiment, and a portion surrounded by a two-dot chain line is different from the control flow of FIG. That is, in the third embodiment, the predetermined time for opening the hot gas valve HV during the protection time of the compressor CM is set to 2 minutes, which is 30 seconds ahead of the other embodiments. Therefore, in step S3 of FIG. 6, it is confirmed whether or not the predetermined time (2 minutes) has elapsed after the activation, and if affirmative (YES), the hot gas valve HV is opened in step S4. Next, in step S5, it is confirmed whether or not a certain time has elapsed after the hot gas valve HV is opened. Here, the time during which the hot gas valve HV is open is set to be sufficiently shorter than the protection time. If step S5 is affirmative (YES), the hot gas valve HV is closed in step S6. Next, in step S7, it is confirmed whether or not the protection time of the compressor CM has passed. If the determination is affirmative (YES), the process proceeds to step S8 to start the compressor CM and drive the water tray opening / closing motor AM to The dish 16 is lowered from the ice making chamber 12 and the deicing operation is started.

  That is, in the second embodiment, the degassing operation is started and the compressor CM is started, and the open hot gas valve HV is closed at the same time. A refrigerant flows in the refrigeration circuit 24. That is, although the hot gas valve HV is closed at the same time, since the refrigerant is flowing, the starting load of the compressor CM is increased. However, in the third embodiment, as shown in FIG. 5 (2), the time A (for example, about 20 seconds) during which the hot gas valve HV is closed is sufficiently secured before the compressor CM is started. When the compressor CM is started after entering the deicing operation, the refrigerant does not flow, so that an excessive load is not applied to the compressor CM at the time of startup. That is, the stability at the time of starting of the compressor CM is increased as compared with the case of the second embodiment.

(Example of change)
(1) In the embodiment, the operation method in which the hot gas valve is closed for a while immediately after starting the compressor during the initial operation of the ice making machine has been described as an example. However, during the initial operation, the low pressure side pressure of the compressor The operating method of the present invention may be carried out only when conditions such as when it is high or when the temperature of the ice making unit is high are met.
(2) In the embodiment, an example of the operation method in which the protection time of the compressor ends and the deicing operation starts when a certain time elapses during the initial operation of the ice making machine has been described as an example. When the pressure sensor detects that the refrigerant pressure with the side has reached equilibrium, the protection time may be terminated and the deicing operation may be started.

12 ice making room (ice making part), 14 evaporator, CD condenser, CM compressor, EV expansion means,
HV hot gas valve

Claims (4)

During ice making operation, refrigerant is supplied from the compressor (CM) to the evaporator (14) via the condenser (CD) and the expansion means (EV), and the ice making unit (12) cooled by the evaporator (14) Ice making water is generated to generate ice blocks, and during the deicing operation, hot gas is supplied from the compressor (CM) to the evaporator (14) via the hot gas valve (HV), and the evaporator In the initial operation of the automatic ice making machine in which ice blocks are detached from the ice making section (12) by heating in (14), a protection time is provided before the compressor (CM) is started, and compression is performed as the protection time elapses In the operation method of starting the machine (CM) and starting the deicing operation,
The compressor (CM) is opened when the hot gas valve (HV) is opened during the protection time of the compressor (CM) and the refrigerant pressures on the high-pressure side and the low-pressure side in the compressor (CM) are substantially balanced. ) To start the deicing operation,
The open hot gas valve (HV) is closed, and the hot gas valve (HV) is kept closed for a while immediately after the start of the compressor (CM) during the deicing operation. How to operate an automatic ice maker.   The method of operating an automatic ice maker according to claim 1, wherein the opened hot gas valve (HV) is closed after the compressor (CM) is started and then opened during the deicing operation.   The method of operating an automatic ice maker according to claim 1, wherein the open hot gas valve (HV) is closed simultaneously with the start of the compressor (CM) and then opened during the deicing operation.   The method of operating an automatic ice maker according to claim 1, wherein the open hot gas valve (HV) is closed during a protection time of the compressor (CM) and then opened during the deicing operation.

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