JP2691771B2 - Ice making control method of ice making machine - Google Patents

Description

The present invention relates to an ice making control method for an ice making machine.

[Conventional technology]

In recent years, the ice making operation of ice making machines has come to be automatically controlled by a microcomputer. In this conventional control method, the characteristic equation of the outside air temperature (room temperature) and the desired evaporator temperature (ice making completion temperature) is obtained in advance by experiments, empirical rules, etc.
The outside temperature is detected by the sensor for detecting the outside temperature, and the temperature for the evaporator is detected by the sensor for detecting the temperature of the evaporator, and the microcomputer detects the outside temperature from the outside temperature-the desired evaporator temperature characteristic formula. Based on this, the desired evaporator temperature is calculated, and when the detected evaporator temperature becomes equal to or lower than the desired evaporator temperature, the ice making is completed, and the desired ice can be obtained throughout the four seasons.

[Problems to be solved by the invention]

However, this conventional control method requires two sensors.
Since the number of individual pieces is also required and the circuit becomes complicated, there is a drawback that it becomes expensive.

Also, the cause of the refrigeration cycle itself (exhaust degree, aging, etc.)
There is also a drawback that changes in the cooling capacity due to changes in the condensing temperature and changes in the power supply frequency due to changes in temperature are not taken into account and these changes cannot be followed.

In view of the above points, an object of the present invention is to make it possible to stably obtain desired ice throughout the four seasons, irrespective of not only changes in outside air temperature but also changes in condensation temperature and power source frequency.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention firstly provides, in an ice making machine, a certain relationship between a falling time of a refrigerating cycle and a predetermined temperature range and an ambient temperature (outside air temperature). When the temperature changes, it is noted that there is a fixed relationship between the falling time and the ice making completion temperature (the desired evaporator temperature).

That is, for example, in the refrigeration cycle shown in FIG. 2 to be described later, when freon 12 is used as a refrigerant to produce ice with a hole diameter of 5 mmφ, the temperature of the evaporator 3b changes from −5 ° C. to −10 ° C. temperature drop time t and the ambient temperature (outside temperature, room temperature) of the T _R in equation I, equation II until the -15 ° C. from -5 ° C., -
Relational expression III from 5 ℃ to -20 ℃, -5 ℃ to -2
The relational expression IV up to 5 ° C is obtained by experiments and empirical rules, and is as shown in Fig. 3.

Further, at that time, the evaporator temperature (ice making completion temperature) T _{sn at} which the ice making is completed at the descent time t is as shown in FIG. That is, for example, the evaporator temperature T _a is −5 ° C.
If it takes 600 seconds to reach −10 ° C., the ice making completion temperature T _sn becomes −16.5 ° C., and if it takes 450 seconds, T _sn becomes −20.0 ° C. Thus, the descent time t
If the temperature is short, the ice making completion temperature T _sn is low.
This is because it is determined by the product of the cooling temperature and the cooling time.

From the above, if the change is the outside air temperature T _R, the fall time t is changed in the evaporator of a predetermined temperature range (predetermined temperature range TN), the fall time t is understood to be involved in the ice-making completion temperature T _sn it can.

That is, to determine the ice-making completion temperature T _sn descent from time t is equivalent to determining the ice-making completion temperature T _sn from the outside air temperature T _R, the fall time t is ice completion temperature T _sn and the outside air temperature T _R It can be seen that it is a variable that mediates and. For this reason,
Regardless outside temperature T _R, to measure the fall time t of a predetermined temperature range TN _n, with its fall time t, determining the ice-making completion temperature T _sn, evaporator temperature T _a has reached its temperature T _sn At some point, ice making may be completed.

Therefore, the present invention focuses on the above points, and when controlling an ice making machine provided with a refrigeration cycle consisting of a compressor, a condenser, a pressure reducer and an evaporator, a predetermined temperature of the evaporator during the operation of the refrigeration cycle. With reference temperature T
_A required number n of measurement temperature zones TN are measured in a negative temperature range from _{ao in the} negative direction, and the temperature drop time t from the reference temperature T _ao to the minimum temperature of the measurement temperature zone TN and the evaporator temperature at the completion of ice making are measured. advance derive relationship between T _sn, in the ice making action, the temperature T _a of the evaporator was measured until the temperature T _a is the respective measure temperature zones TN since became the reference temperature T _ao Temperature drop time t of the ice making completion evaporator temperature T _sn corresponding to the temperature drop time t is calculated from the relational expressions (I, II ...) Up to the respective measurement temperature zones TN, and the calculated temperature T
_sn is the next 2 of the measured temperature range TN _n of the calculated relational expression
The ice making completion evaporator temperature T _sn according to the temperature drop time t is entered until one of the two measured temperature zones TN _{n + 1} and TN _{n + 2} is entered.
The above measurement temperature band TN _{n + 1} or TN _{n + 2} is repeated.
When it reaches the, by the calculated temperature T _sn and ice complete evaporator temperature T _S in this ice making action, the temperature T _S, when the measured temperature T _a of the evaporator becomes, and so the ice-making completion Of.

The predetermined (reference) temperature T _ao of the evaporator is a value at which the elapse time t of the evaporator is stable without being affected by the water temperature, and is, for example, −5.
If ° C. and water supply is at any temperature, at -5 ° C. is constant becomes close 0 ° C., then, the outside air temperature T _R, the condensation temperature of the refrigeration cycle, the power supply frequency changes fall time t is determined It

The narrower the predetermined temperature range TN is, the more accurate the accuracy is.
Considering the accuracy of the temperature detection sensor (thermometer), the interval is, for example, 5 ° C. as appropriate. The number of bands _n is determined by the temperature drop during the ice making of the evaporator and the temperature band width. When CFC 12 is used as the refrigerant, the temperature drop is −
Since 25 ° C is appropriate, _n = 4 at 5 ° C intervals.

The calculation is repeated until the calculated temperature T _{sn for the} completion of ice making falls into either of the next measurement temperature zones TN _{n + 1} or TN _{n + 2} .
This is because the wider the temperature range to be measured, the more various disturbances can be absorbed and the more accurate ice making completion temperature T _sn can be selected.

It should be noted that the ice making completion temperature T _S can take into consideration the information A for determining the hole diameter of ice as in the embodiment.

〔Example〕

FIG. 2 shows an example of a refrigerating cycle of an upward jet type ice making machine constituted by a general water / refrigerant circuit controlled by the method of the present invention, which is provided at an upper portion of an ice storage (not shown). Ice water tank 2 configured to be rotatable integrally with the water tray 1.
The ice-making water tank 2 is in contact with the ice tray 3 at the rising position of the solid line in the drawing during the ice making operation, and is in the descending position of the chain line in the drawing during the ice removing operation to separate from the ice tray 3. It is driven by a dish drive motor RM (not shown). This drive is performed by a changeover switch (not shown) for detecting the position of the water tray 1.

The ice tray 3 has a large number of ice making compartments 3a and an evaporator 3b each having an opening at the bottom thereof.
Then, the circulation pump 12 pumps the ice making water from the ice making water tank 2 into the water tray 1, and the ice making water is passed through the small holes provided in the water tray 1 to the ice making small chambers 3a as shown by the dotted lines in FIG. When the fountain is sprayed, the ice a shown in FIG. 5 (in the figure, the top and bottom of the ice cube are opposite) gradually grows on the inner wall of the ice making chamber 3a.

The ice tray 3 is cooled by the evaporator 3b. The high-temperature and high-pressure refrigerant gas (Freon 12) compressed by the compressor 5 is cooled and liquefied by the condensing fan motor 7 in the condenser 6 and expanded by the capillary tube 8 and then evaporated. The liquefied refrigerant gas is sent to the vessel 3b and is evaporated while passing through the evaporator 3b.
This is performed by a refrigeration cycle in which heat equivalent to the heat of vaporization is taken from and vaporized and returned to the compressor 5.

A sensor 4 for detecting the temperature is attached to the evaporator 3b, and the ice making completion temperature T _S is determined by the control method described later based on the measured temperature T _a , and the temperature T _S is measured.
When T _a is reached, de-icing operation is started.

In this deicing operation, first, the water tray drive motor RM is driven by the detection signal of the temperature detection sensor 4 to lower the water tray 1 and the ice making water tank 2, and the water tray drive motor is moved to the lowered position.
When the RM operates the changeover switch to stop, the hot gas valve 10 provided in the bypass passage 9 opens, and the high-temperature and high-pressure refrigerant gas from the compressor 5 passes through the bypass passage 9 and the evaporator.
It is sent to 3b and the ice tray 3 is heated. At the same time, the water supply valve 11 is opened, and the melted ice water is guided from the water supply valve 11 to the ice tray 3 and the water tray 1 to melt the ice with a flash, and this melted ice water is used for the next ice making operation. It is stored in the ice making water tank 2 as ice making water. By this heating and water supply, the ice making small chamber
The ice a in 3a is melted at its periphery and separated from the ice tray 3 to be dropped and stored in the ice storage.

When the evaporator temperature detection sensor 4 detects the de-icing completion temperature, the water tray drive motor RM rotates in the reverse direction, the water tray 1 and the ice making water tank 2 rise, and the water tray drive motor RM in the raised position.
Operates the changeover switch to stop and simultaneously closes the hot gas valve 10 and the water supply valve 11 to start the next ice making operation.

The above operation is the ice making end control, that is, the ice making completion temperature.
Other than the determination of T _S , this is the same as the known technique described in Japanese Utility Model Publication No. 62-9491, and the ice making end control, which is a feature of the present invention, will be described.

First, as shown in FIG. 4, the relational expression between the temperature drop time t corresponding to the temperature zone TN and the ice making completion temperature T _sn is determined by experiments and empirical rules. This relational expression I ′, II ′, III ′, I
V ′ is the case where the hole b of the ice a shown in FIG. 5 is 5 mmφ,
The ice making completion temperature T _sn obtained from each relational expression is the required temperature A
If it is increased (for example, when the ice making completion temperature T _sn is −23 ° C.,
If A: 2 ℃ is raised from -23 ℃ to -21 ℃), the growth of the ice a is stopped early, and the diameter of the hole b becomes large. Conversely, if the required temperature A is lowered, the ice a Of the holes, the diameter of the hole b becomes smaller. This required temperature A is
Make appropriate selections based on experiments and empirical rules.

Therefore, at the time of ice making, the controller C stores the above relational expressions I ′ to IV ′ and inputs the temperature A information, and then the ice making is started. Ice making started, evaporator 3b
When the temperature of 5 reaches -5 ° C, time measurement is started and the fall time t to -10 ° C is measured. Based on this measured value, the ice making completion temperature T _sn is calculated as described above, and the temperature T _sn
The ice making completion temperature T _sn is determined by repeating the calculation until the temperature reaches either of the following temperature zones TN _{n + 1} and TN _{n + 2} .

If determined in this ice-making completion temperature T _sn is, the temperature T _sn of the value Ts obtained by adding the temperature A information, it continued cooling until the measurement value T _a from the sensor 4 is, at a temperature Ts, the ice-making action Stop and proceed to the de-icing action described above. The above flow chart is shown in FIG.

〔The invention's effect〕

Since the present invention is configured as described above, and the ice making completion temperature is determined by the evaporator fall temperature time corresponding to changes in the outside air temperature, the condensation temperature and the power supply frequency, the outside air temperature, the condensation temperature and the power supply frequency Even if the temperature changes, the desired ice can be obtained throughout the four seasons, and stable and accurate ice-making can be performed without adjustment throughout the year.

Further, since the sensor for correcting the outside air temperature is not required, the circuit is simplified and an inexpensive product can be provided.

[Brief description of the drawings]

FIG. 1 is a flow chart of an embodiment of an ice making control method for an ice making machine according to the present invention, FIG. 2 is a schematic view of an upward jet ice making machine of the same embodiment, and FIGS. 3 and 4 are temperature drop. FIG. 5 is a diagram showing the relationship between time, ambient temperature and ice making completion temperature, and FIG. 5 is a perspective view of the ice produced in the example. 1 ... Water tray, 2 ... Ice making water tank, 3 ... Ice making tray, 3a ... Ice making chamber, 3b ... Evaporator, 4 ... Evaporator temperature detection sensor, 5 ... Compressor, 6 ... Condenser, 7 ... Condensing fan motor, 9 ... Bypass passage, 10 ... Hot gas valve, 11 ... Water supply valve, C ... Controller, a ... Ice, b ... Hole, _Ta ... Evaporation Vessel temperature, T _ao …… Reference temperature, Tsn, Ts …… Ice-making completion temperature (evaporator temperature), t …… Temperature drop time.

Claims (1)

(57) [Claims] 1. When controlling an ice maker having a refrigeration cycle including a compressor, a condenser, a decompressor and an evaporator, a predetermined temperature of the evaporator during the operation of the refrigeration cycle is used as a reference, and the reference temperature is used as the reference temperature. Determining the required number of measurement temperature zones in the negative direction on the predetermined temperature axis, and deriving in advance the relational expression between the temperature drop time from the reference temperature to the minimum temperature of the measurement temperature zone and the evaporator temperature at the completion of ice making. In the ice making operation, the temperature of the evaporator is measured, and the temperature drop time from when the temperature reaches the reference temperature to each of the measured temperature zones is measured. Calculate the ice making completion evaporator temperature corresponding to the temperature drop time from the formula,
Until the calculated temperature falls within one of the two measured temperature zones next to the measured temperature of the calculated relational expression, the calculation of the ice making completion evaporator temperature based on the temperature drop time is repeated,
When entering the next measurement temperature zone, the calculated temperature is set as the ice making completion evaporator temperature in this ice making operation, and when the measured temperature of the evaporator is reached, the ice making control of the ice making machine is completed Method.