JP2006336931A - Auger type ice machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an auger type ice machine carrying out control of resolving a "co-rotation phenomenon" wherein ice in a cylinder rotates along with an auger. <P>SOLUTION: The auger type ice machine 100 is provided with a pulse encoder 14 detecting a rotational frequency of a geared motor 9 driving the auger 5, a temperature detector 50 detecting a temperature of an outlet 2b of an evaporator 2, an inverter 28 controlling a rotational frequency of a compressor 3, and a control part 29 controlling them. If the rotational frequency of the geared motor 9 is larger than a predetermined value, and the temperature of the evaporator outlet 2b is lower than a predetermined value, the control part 29 judges that there is co-rotation, and it controls the inverter 28 to lower the rotation of the compressor 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an auger type ice making machine, and more particularly to control of a compressor.

Generally, an auger type ice making machine includes an ice making cylinder that cools internal ice making water into ice. A pipe-shaped cooling evaporator is wound around the outer peripheral surface of the cylinder, and an auger is provided inside the cylinder so as to be coaxial with and rotatable about the longitudinal axis of the cylinder. The evaporator is included in the refrigeration circuit along with the compressor.
A spiral blade is provided on the outer peripheral surface of the auger. The ice-making water supplied into the cylinder is cooled by the evaporator and is iced on the inner peripheral surface of the cylinder. The ice grown on the inner peripheral surface of the cylinder is scraped off by a helical blade of an auger that is rotated by a guard motor, and is scraped up by a screw feed action. The icing pieces scraped up are compressed by a compression passage provided above the cylinder, and cut by a fixed blade to produce chip-shaped ice.

In an auger type ice making machine, if ice grows inside the cylinder, hunting occurs due to overloading of the guard motor, which may cause troubles such as breakage of gears in the guard motor or breakage of the auger.
Therefore, in order to avoid such hunting, an auger type ice making machine having an inverter circuit that detects the temperature at the outlet of the evaporator and adjusts the rotation speed of the compressor when it is determined to be supercooled has been devised. . An example of such an auger type ice making machine is shown in Patent Document 1.
Further, a device has been devised that detects the load current of a geared motor and adjusts the rotational speed of the compressor when it is determined that the load is overloaded.

JP-A-8-178487

However, in the auger type ice making machine as described above, there is a problem that this cannot be solved when "co-rotation" which is one of the internal ice clogging phenomenon occurs.
Co-rotation means that the ice attached to the spiral blade and the ice in the compression passage are separated between the spiral blade rotating integrally with the auger and the fixed compression passage, and the ice attached to the spiral blade. Is a phenomenon in which the auger rotates integrally with the auger and is not conveyed to the upper part.

  When the co-rotation occurs, the ice in the cylinder is not discharged and water is not supplied to the cylinder, so the temperature in the evaporator and the cylinder decreases. If this state continues, the ice overgrown in the cylinder will eventually cause the auger to lock, that is, stop rotating, and overload will be applied to the guard motor that drives the auger. As a result, troubles such as breakage of gears in the geared motor and breakage of the auger may occur.

  The present invention has been made to solve such problems, and an object thereof is to provide an auger type ice making machine that performs control to eliminate co-rotation.

  To achieve the above object, an auger type ice making machine according to the present invention includes a refrigeration circuit including a compressor and an evaporator, temperature detecting means for detecting a temperature at a predetermined portion of the evaporator, a motor for driving the auger, and a motor. And a control means for controlling the rotation speed of the compressor based on the temperature detected by the temperature detection means and the rotation speed detected by the rotation speed detection means. .

  According to the present invention, since the common rotation is detected and the rotation speed of the compressor is reduced based on the temperature at the predetermined portion of the evaporator and the rotation speed of the guard motor, the rotation can be eliminated.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 shows a configuration of an auger type ice making machine 100 according to the first embodiment. A cooling evaporator 2 is wound around the outer peripheral surface of the cylinder 1. A compressor 3 and a condenser 4 are connected to the evaporator 2.

The refrigerant circulates in the direction of arrow (a) through the inside of the refrigeration circuit including the evaporator 2, the compressor 3, the condenser 4, and the expansion valve 15. Of the two end portions of the evaporator 2, the side where the refrigerant flows into the evaporator 2 from the condenser 4 is the evaporator inlet 2 a, and the side where the refrigerant flows out from the evaporator 2 to the compressor 3 is the evaporator outlet 2 b. In the vicinity of the evaporator outlet 2b, a temperature detector 50 is attached as temperature detecting means for detecting the temperature of the evaporator outlet 2b (hereinafter referred to as “exit temperature”).
The position at which the temperature detector 50 is attached is not limited to the evaporator outlet 2b, and may be any part of the refrigeration circuit until the refrigerant reaches the compressor 3 after passing through the expansion valve 15. . Moreover, the evaporator inlet 2a may be sufficient.

  An auger 5 is provided in the cylinder 1 so as to be coaxial and rotatable with the longitudinal axis of the cylinder 1. A spiral blade 6 is provided on the outer peripheral surface of the auger 5. Above the cylinder 1, a pressing head 7 having a compression passage 7a is provided. A fixed blade 8 is provided above the pressing head 7. Below the cylinder 1, a guard motor 9 which is a motor for driving the auger 5 is provided. The geared motor 9 includes a motor unit 10 and a speed reduction unit 11. The lower end of the auger 5 is connected to the motor unit 10 via the speed reduction unit 11. The motor unit 10 has a rotor 12. The rotor 12 includes an output shaft 13.

The output shaft 13 is provided with a pulse encoder 14 to be described later as means for detecting the rotational speed of the rotor 12. A geared motor power supply 16 is connected to the geared motor 9 to supply power. The compressor 3 is connected to a compressor power supply 18 via an inverter 28 to supply power.
The inverter 28 is connected to a control unit 29 as control means. The control unit 29 controls the frequency of the inverter 28, thereby determining the rotation speed of the compressor 3. That is, the control unit 29 indirectly controls the rotational speed of the compressor 3. As the frequency of the inverter 28 increases, the rotational speed of the compressor 3 increases.
The control unit 29 receives signals from the pulse encoder 14 and the temperature detector 50, and controls the frequency of the inverter 28 based on the signals. The control unit 29 may perform other controls related to the operation of the auger type ice making machine 100.

  FIG. 2 shows an enlarged view including the upper part of the spiral blade 6 and the compression passage 7a. Co-rotation occurs when ice separates between the upper end of the spiral blade 6 (end on the compression passage 7a side) and the lower end of the compression passage 7a (end on the spiral blade 6 side), that is, around the portion B.

  The pulse encoder 14 will be described with reference to FIGS. 3 and 4. The pulse encoder 14 includes a Hall IC 20 and a rotating magnet 21. The Hall IC 20 is fixed at a position facing the rotating magnet 21. The Hall IC 20 is connected to the Hall IC power supply 22 and the control unit 29. The rotating magnet 21 is attached to the output shaft 13 that rotates integrally with the rotor 12, and rotates integrally with the output shaft 13. FIG. 4 is a plan view including the configuration of the magnetic poles of the rotating magnet. The rotating magnet 21 shown in FIG. 4 has four poles, but this does not have to be four poles.

  The Hall IC 20 has a magnetic sensor unit. The magnetic sensor unit detects the rotational speed of the output shaft 13 by sensing the magnetism of the rotating magnet 21. For example, when a four-pole rotating magnet is used, a magnetic sensor unit detects a pole at a position facing the Hall IC 20, for example, an N pole. Since the rotating magnet 21 rotates together with the output shaft 13, the pole of the rotating magnet 21 facing the Hall IC 20 changes with rotation. Therefore, the magnetic sensor that first detects the N pole then detects the S pole. After that, it senses similarly as N pole and S pole. Since a four-pole rotating magnet is used, if the magnetic sensor detects the N-pole and the S-pole twice each, the output shaft 13 is rotated once. In this way, the control unit 29 detects the rotational speed of the output shaft 13.

  Next, the operation of the auger type ice making machine 100 according to Embodiment 1 will be described. The cylinder 1 is cooled by the evaporator 2. The refrigerant for cooling the evaporator 2 circulates from the evaporator 2 to the compressor 3, from the compressor 3 to the condenser 4, and from the condenser 4 to the evaporator 2, as indicated by an arrow (a). The ice making water supplied into the cylinder 1 is cooled and icing on the inner peripheral surface of the cylinder 1. The frozen ice pieces are scraped off by the spiral blade 6 of the auger 5 rotated by the guard motor 9. The frozen pieces are scraped up to the compression passage 7a above the cylinder 1 by the spiral blade 6 by the screw feeding action. The ice pieces are compressed in the compression passage 7a and cut by the fixed blade 8 to make chip-shaped ice.

  The geared motor 9 transmits the rotation of the rotor 12 of the motor unit 10 to the auger 5 via the output shaft 13 and the speed reduction unit 11 to rotate the auger 5. The rotation speed of the rotor 12, that is, the rotation speed of the output shaft 13 and the rotating magnet 21 is detected by the pulse encoder 14. The detected number of rotations is input from the pulse encoder 14 to the control unit 29 as a signal. Since the speed reduction ratio of the speed reduction unit 11 is constant, the control based on the rotational speed of the output shaft 13 is the same as the control based on the rotational speed of the auger 5.

  The control unit 29 controls the inverter 28 based on this signal. This control is performed so that the rotation speed of the compressor 3 is kept constant when the outlet temperature is not too low, and the compression is performed when the outlet temperature is too low and the rotation speed of the guard motor 9 is higher than normal. This is done so as to reduce the rotational speed of the machine 3. Details of this control are as follows.

In the control unit 29, threshold values T1 and T2 of the outlet temperature, lower limit R1 and upper limit R2 of the target rotational speed of the guard motor 9, and frequencies F1 to F4 of the inverter 28 are set in advance.
Here, with respect to the outlet temperature, T1 ≦ T2, T1 is a threshold value that is a criterion for determining the occurrence of co-rotation, and T2 is a threshold value that is a criterion for determining whether the ice making capacity is excessive or insufficient. Further, with respect to the frequency of the inverter 28, F1 ≦ F2 ≦ F3 ≦ F4, F1 is a set value corresponding to the control for extremely reducing the rotational speed of the compressor 3 in order to eliminate the co-rotation, and F2 is the ice making capacity When the number is excessive, this is a setting value corresponding to control for slightly reducing the rotation speed of the compressor 3, and F3 is a setting value corresponding to control for maintaining the rotation speed of the compressor 3 at a standard when the ice making capacity is appropriate. Yes, F4 is a set value corresponding to control for slightly increasing the rotational speed of the compressor 3 when the ice making capacity is insufficient.
Specific values of each parameter are, for example, T1 = −25 (° C.), T2 = −18 (° C.), R1 = 1720 (rpm), R2 = 1740 (rpm). F1 to F4 are values selected from, for example, the frequency of the inverter 28 that operates the compressor 3 at 1800 rpm or a frequency in the vicinity thereof. The values of T1, T2, R1, R2, and F1 to F4 may be changeable.

The flow of control by the control unit 29 is shown using the flowchart of FIG.
The control unit 29 compares the rotational speed R of the guard motor 9 detected by the pulse encoder 14 with the lower limit R1 and the upper limit R2 of the target rotational speed (step S1). When R <R1, the control unit 29 sets the frequency of the inverter 28 to F2 (step S2), and then returns to step S1. This corresponds to adjustment when the ice making capacity is excessive during normal operation. As a result of this adjustment, the compressor 3 is rotated at a low speed, so that the refrigeration capacity of the refrigeration circuit is lowered, the amount of icing on the inner peripheral surface of the cylinder 1 is reduced, the load on the guard motor 9 is reduced, and the rotational speed R is increased. However, it becomes larger than the lower limit R1 of the target rotational speed.

  If R1 ≦ R ≦ R2 in step S1, the control unit 29 sets the frequency of the inverter 28 to F3 (step S3), and then returns to step S1. This corresponds to adjustment when the ice making capacity is appropriate during normal operation. By this adjustment, since the compressor 3 has a standard rotational speed, the refrigeration capacity of the refrigeration circuit is maintained at the standard, the amount of icing on the inner peripheral surface of the cylinder 1 is maintained, and the load of the guard motor 9 does not change. R is kept constant.

If R> R2 in step S1, the control unit 29 compares the outlet temperature T detected by the temperature detector 50 with the outlet temperature thresholds T1 and T2 (step S4).
In step S4, if T> T2, the frequency of the inverter 28 is set to F4 (step S5), and then the process returns to step S1. This corresponds to adjustment when the ice making capacity is insufficient during normal operation. Since the compressor 3 is rotated at a high speed by this adjustment, the refrigeration capacity of the refrigeration circuit is increased, the amount of icing on the inner peripheral surface of the cylinder 1 is increased, the load on the guard motor 9 is increased, and the rotational speed R is decreased. The target rotational speed becomes smaller than the upper limit R2.

  In step S4, if T1 ≦ T ≦ T2, the frequency of the inverter 28 is set to F3 (step S6), and then the process returns to step S1. This corresponds to an adjustment corresponding to an abnormal state called pipe peeling, in which the evaporator 2 is peeled off from the outer peripheral surface of the cylinder 1. Due to this adjustment, the compressor 3 has a standard rotational speed, so that the refrigerating capacity is not lowered, and the ice making capacity is maintained even if the pipe is peeled off.

  In step S4, when T <T1, the control unit 29 sets the frequency of the inverter 28 to F1 (step S7), and then returns to step S1. This corresponds to an adjustment corresponding to an abnormal state in which co-rotation occurs. By this adjustment, the compressor 3 is rotated at a very low speed, so that the refrigerating capacity of the refrigerating circuit is extremely low, and the state of excessive refrigerating capacity is eliminated. Thus, co-rotation is eliminated.

As described above, the auger type ice making machine 100 detects the rotational speed of the guard motor 9 and the outlet temperature, controls the inverter 28 based on the detected value, and adjusts the rotational speed of the compressor 3.
Basically, a decrease in the rotation speed of the guard motor 9 is determined as ice overgrowth, and the rotation speed of the compressor 3 is adjusted so as to approach the predetermined rotation speed. That is, when the speed of the geared motor is higher than a predetermined value, it is determined that the load is light, and the speed of the compressor 3 is increased. When the speed of the geared motor is lower than the predetermined value, it is determined that the load is overloaded. Reduce the number of revolutions of machine 3. However, if it is detected that the number of rotations of the guard motor is higher than a predetermined value and the outlet temperature is lower than a predetermined threshold, it is determined that co-rotation has occurred, and adjustment is made to decrease the rotation speed of the compressor.

Therefore, the auger type ice making machine 100 can eliminate co-rotation. This also solves the problems that occur with the co-rotation, such as ice supply stop due to ice clogging, damage to the guard motor 9 due to hunting of the guard motor 9, breakage of the auger 5 due to hunting of the guard motor 9, and the like.
In addition, since the refrigeration capacity of the compressor 3 can be controlled, the frequency of abnormal noise due to overgrowth of ice can be reduced.

In addition to the above effects, the auger type ice making machine 100 can obtain the following advantageous effects over the conventional auger type ice making machine.
The control of the compressor 3 in the auger type ice making machine 100 is based on the number of revolutions of the guard motor 9 directly detected by the pulse encoder 14, and thus compared with the control based on the outlet temperature and the conventional control based on the load current flowing through the guard motor 9. Responsiveness is good. This can prevent ice overgrowth. Further, since the variation in the rotational speed of the guard motor 9 is small compared to the change in load current due to the voltage fluctuation of the guard motor 9 or the difference in load current due to individual differences between different guard motors 9, the threshold value can be easily set.

  Further, in the conventional auger type ice making machine, since the response is relatively low as described above, it is delayed to eliminate the excessive refrigeration capacity, and the temperature detector 50 is exposed to a low temperature for a long time. For this reason, for example, a special thermistor for low temperature that can withstand continuous use at −20 ° C. is required. On the other hand, since the auger type ice making machine 100 according to the first embodiment has good responsiveness as described above, a special thermistor as in the past can be dispensed with.

  In general, in an auger type ice making machine, the outlet temperature does not change so much during normal operation. That is, the difference in outlet temperature is relatively small between the case where the engine is operated with an appropriate refrigeration capacity during normal operation and the case where the refrigeration capacity becomes excessive during normal operation. Therefore, it is difficult to control the number of rotations of the compressor in multiple stages during normal operation with the conventional system that performs control based only on the outlet temperature. On the other hand, since the auger type ice making machine 100 according to the first embodiment performs control based on the outlet temperature and the rotation speed of the guarded motor 9, the inverter 28 in multiple stages such as F2 to F4 described above during normal operation. Frequency control is possible, and the refrigerating capacity can be adjusted more finely.

  Moreover, generally, when pipe peeling occurs, the efficiency of heat exchange in the evaporator decreases, the refrigeration capacity decreases, and the outlet temperature also decreases. In the conventional system that performs control based only on the outlet temperature, it detects that the outlet temperature has dropped and determines that the refrigeration capacity is excessive, and performs control to reduce the number of revolutions of the compressor. Get smaller. On the other hand, since the auger type ice making machine 100 according to the first embodiment performs control based on the outlet temperature and the rotation speed of the guard motor 9, it is possible to detect the pipe peeling state. Therefore, even if pipe peeling occurs, control corresponding to this can be performed accurately, and the ice making capacity can be maintained.

  In the first embodiment described above, the rotation speed detection means is the pulse encoder 14 that detects the fluctuation of the magnetic field generated by the rotation of the rotating magnet 21, but this may be other. For example, a rotary encoder including a turntable having a slit, a light emitting element, and a light receiving element may be used. In such a rotary encoder, the slit passes between the light emitting element and the light receiving element as the turntable rotates, and the light receiving element emits light through the slit only while the slit exists between the light emitting element and the light receiving element. Receives light from the element. By counting the number of times of light reception, the number of rotations of the rotating disk, that is, the number of rotations of the rotor 12 is detected.

  Further, the set value F1 of the frequency of the inverter 28 for eliminating the co-rotation may be zero. That is, in step S6 of FIG. 5, control for stopping the operation of the compressor 3 may be performed. By carrying out like this, co-rotation can be eliminated earlier.

  In Embodiment 1, a heater may be attached. This heater is attached to, for example, the fixed blade 8 or the vicinity thereof. In this configuration, when it is determined that co-rotation has occurred, the control unit 29 may cause the heater to generate heat instead of or in addition to lowering the rotational speed of the compressor 3. As a result, it is possible to more reliably eliminate the excessive cylinder 1 refrigeration capacity.

It is a figure which shows the structure of the auger type ice making machine 100 which concerns on Embodiment 1 of this invention. It is a figure which shows the enlarged view containing the upper part of the spiral blade 6 and the compression channel | path 7a of the auger type ice making machine 100 of FIG. It is a figure which shows typically the pulse encoder 14 in the auger type ice making machine 100 of FIG. It is a top view which shows a part of pulse encoder 14 of FIG. 4 is a flowchart showing a flow of control of the auger type ice making machine 100 according to the first embodiment.

Explanation of symbols

  2 Evaporator, 3 Compressor, 9 Motor (Gard motor), 14 Rotational speed detection means (pulse encoder), 29 Control means (control part) 50 Temperature detection means (temperature detector), 100 Auger type ice making machine.

Claims (1)

An auger ice machine,
A refrigeration circuit including a compressor and an evaporator;
Temperature detecting means for detecting a temperature at a predetermined portion of the evaporator;
A motor that drives the auger;
A rotational speed detection means for detecting the rotational speed of the motor;
An auger type ice making machine comprising: control means for controlling the rotation speed of the compressor based on the temperature detected by the temperature detection means and the rotation speed detected by the rotation speed detection means.

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