JP2567898B2 - Operation control device for ice making device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the operation of an ice making device in which sherbet-like ice is generated with an ice making solution and stored in a heat storage tank to obtain a cold heat source such as cooling. Regarding the control device.

(Prior Art) Conventionally, an ice making device of this type is disclosed in Japanese Patent Laid-Open No. 56-2567, and as shown in FIG. 9, a blade (F ) Is installed inside, and the evaporator (E) in the refrigerating apparatus configured by using a compressor is coiled between the inner pipe (A) and the outer pipe (B). The sherbet-shaped ice is dropped into the heat storage tank (C) arranged below by the cooling operation by the evaporator (E) and the ice removing operation by the blade (F), and the heat storage tank is also installed. Cooling heat is supplied between the liquid area of (C) and the upper part of the inner pipe (A) via a circulation pump (P), and is supplied to the indoor unit (U) in the daytime by using midnight power or the like. It is known that a source is obtained in advance so that it can contribute to energy saving.

As the ice-making solution that is made into sherbet-like ice, an aqueous solution obtained by adding ethylene glycol or the like to water so as to freeze below the freezing point of water (0 ° C.) is generally used.

(Problems to be Solved by the Invention) In this type of ice making device, it is desirable to store as much sherbet-like ice as possible in the heat storage tank (C) from the viewpoint of securing the heat storage amount. However, while it is necessary to circulate and flow the ice-mixed solution between the inner tube (A) and the heat storage tank (C) while preventing freezing in the inner tube (A), the total weight of the solution (W1 ) And the weight of ice produced (W2) (W2
/ W1) (hereinafter referred to as IPF (Ice Packing Factor)) is limited to about 40 to 60%, and if you try to obtain a higher IPF, you will freeze it in the inner pipe (A). There arises a problem that the rotary drum (D) freezes and locks.
Therefore, it is necessary to operate while controlling the amount of ice produced, that is, the IPF limit value.

In addition, when the number of operating indoor units (U) is small, there are cases where it is desired to operate at an IPF lower than the IPF limit value due to the demand for indoor heat load.

In this case, the generated ice itself is a water-only crystal,
As the concentration of the solution increases with the formation of ice, the temperature at which ice is newly generated, that is, the freezing point, lowers, and the solution temperature is constantly detected. It is possible to stop the operation of the compressor that supplies the cooling medium. However, in such a case, if the initial concentration of the solution changes, the temperature itself at which ice formation first starts differs, so even if the operation is stopped at a specific temperature, the temperature will decrease by the ice formation start temperature. It is not possible to evaluate the temperature, and it is not possible to obtain an accurate ice storage amount. Also, because of the specific temperature, that is, the absolute value detection,
Variations in the temperature detector cause variations in the amount of ice storage.

The object of the present invention is not affected by the initial concentration of the solution by controlling the start and stop of the compressor by the difference between the freezing start temperature and the temperature that decreases with the subsequent increase in concentration, that is, the relative value of the solution temperature. Another object is to provide an operation control device in an ice making device that can be controlled to a predetermined IPF without being affected by variations in temperature detectors.

(Means for Solving the Problem) Therefore, in the present invention, an inner pipe (2) having a rotary drum (5) as an internal component for circulating a solution for ice making and an outer pipe (3 for circulating a refrigerant for cooling the solution). ) And an ice making evaporator (1), and a refrigeration cycle having a compressor (8) for supplying the refrigerant to the outer pipe (3). Freezing detection means for detecting the freezing start of the solution in the inner pipe (2), a temperature detector (Th) for detecting the outlet temperature of the inner pipe (2), and the freezing start is detected by the freezing detection means. Storage means for storing the outlet temperature (T1) detected by the temperature detector (Th) at the time of storage, and the outlet temperature (T2) detected by the temperature detector (Th) after the start of freezing and the stored outlet temperature (T1) Difference with (T1-T
And a compressor starting / stopping means for controlling the starting / stopping of the compressor (8) based on 2).

(Function) The difference between the solution temperature (T1) at the start of freezing and the solution temperature (T2) which decreases due to the increase in the solution concentration after freezing is calculated, and this difference (T1-T2) is used to start and stop the compressor (8). By performing the control, the amount of ice produced, and thus the ice storage rate IPF, can be controlled by the relative value of the temperature detected by the temperature detector (Th), which makes it possible to control a predetermined value without being affected by the initial concentration of the solution. The amount of ice storage is obtained. Also, even if the detected value of the temperature detector (Th) may appear higher or lower than the actual value,
Since it is controlled by the difference between the two detection values, it is not affected by the variation of the detector (Th).

(Example) What is shown in FIG. 5 and FIG. 6 is an evaporator (1) for ice making.
And an inlet (21) for the ice-making solution at one axial end,
An inner tube (2) having an outlet (22) for the solution at the other end,
An outer pipe (3) having an inlet (31) and an outlet (32) for the refrigerant is provided, and the inner pipe (2) is in sliding contact with the inner peripheral surface (20) of the inner pipe (2). A rotary drum (5) equipped with a blade (4) is incorporated, and the solution is cooled by the refrigerant using the inner peripheral surface (20) as a heat transfer surface.

The blade (4) is divided into four along the axial length of the rotary drum (5) into four pairs (4a, 4a) (4b, 4b) (4c, 4
c) (4d, 4d) are arranged, and each pair is provided to face each other with 180 ° on the circumference of the rotating drum (5), and each pair is the axial length of the rotating drum (5). 45 along each other
It is provided by deviating by ° C.

As shown in FIG. 1, the evaporator (1) configured as described above is
The two drums are paired, and the drive shafts (50) (50) of the rotary drums (5) (5) are driven by one motor (M2).
The inner pipes (2) and (2) are connected in series by a communication pipe (63), and a solution supply pipe (61) is connected to a first-stage inlet (21) and a second-stage outlet (22). The heat storage tank (6) is connected by connecting the return pipe (62), and the heat storage tank (6) and each inner pipe (2) (2) are connected via a circulation pump (7) interposed in the supply pipe (61). ) To circulate the solution. On the other hand, the outer tubes (3) (3) are connected in parallel with each other, and the compressor (8)
And is connected to a refrigeration system (10) that constitutes a refrigeration cycle.

The refrigerating device (10) is provided with an oil separator (11) and a water-cooled condenser (12) from the discharge side of the compressor (8), and a two-way branch path through a flow divider (13). (14) An ejector (15) for providing (14) in parallel and expanding the condensed high-pressure liquid refrigerant in each branch path, and the outer pipe (3) for performing an evaporating action of the expanded low-pressure liquid refrigerant. The outlet is integrated with a header (16), and further connected to the suction side of a compressor (8) via an accumulator (17).

In Fig. 1, (18) is the outlet pipe (12) of the condenser (12).
0) and the suction pipe (80) of the compressor (8) are attached so as to be capable of heat exchange, (19) (19) are equalizing pipes of the ejectors (15) (15), and (M3) is the compressor motor,
(SV) is a closing valve, (BV) is a check valve, (RI) is a liquid eye, (DF) is a dryer filter, (HPS) is a high pressure detector, (HG) is the same high pressure gauge, (LPS). Is a low pressure detector and (LG) is a low pressure gauge. Also (M1)
Is a circulation pump motor.

Then, a temperature detector (Th) such as a thermistor for detecting the outlet temperature of the solution flowing out from the inner pipe (2) is interposed in the solution return pipe (62).

Further, an ice-free detecting means (91) for detecting the start of freezing at the temperature detected by the temperature detector (Th) is constituted. As shown in the flow chart of FIG. 2, when the solution starts to freeze, the latent temperature of the solution and the refrigerant are mainly exchanged, and the detected temperature of the solution changes to almost constant (see FIG. 3). ) Is detected from that.

The solution temperature (T1) when the start of freezing is detected is stored in the storage means (92). Further, this storage means (92)
When the difference (T1-T2) between the temperature (T1) stored in the memory and the temperature (T2) after the start of freezing exceeds the set value (T0), the compression is started via the compressor start / stop means (93). Stop the operation of the machine (8).

The reason why the IPF can be controlled to the set value based on the temperature difference (T1-T2) is as follows.

That is, the addition amount (weight) of ethylene glycol in the solution is (x), the initial concentration (weight ratio) of the solution before freezing is (a1), the solution weight is (W1), and the solution outlet temperature is (T1), After freezing, the concentration when only ice (W2) is produced (W2) is the concentration (a2), and the temperature due to the decrease in freezing point due to the concentration increase (T
2) Then, a1 ＝ x / W1 a2 ＝ x / (W1−W2) ∴W2 ＝ W1 ・ (a2−a1) / a2 Therefore, when ice (W2) is generated, IPF ＝ W2 / W1 ＝ ( a2-a1) / a2.

Here, as shown in FIG. 4, the IPF gradually approaches 1 or 100% as the solution concentration increases, but the IPF limit value is at most 40 to 60%, and within this range.
Since the IPF is to be set, the solution concentration and IPF
The correspondence with and is almost linear.

On the other hand, since the relationship between the solution concentration and its freezing point changes almost linearly, the IPF per unit temperature, that is, {(a2-a1) / a2} / (T1-T2) is set as the constant (C). And IPF is expressed as a function of temperature difference (T1-T2) and is obtained from the following equation.

IPF = C · (T1-T2) Therefore, the difference between the solution temperature at the start of freezing (T1) and the solution temperature after freezing (T2) is calculated, and this difference (T1-T2) is obtained as the set IPF. The desired set IPF can be obtained by discontinuing the operation when the temperature difference at the time of heating, that is, the set value (T0) or more is reached.

As described above, in order to obtain the set IPF with the temperature difference (T1-T2), that is, because the control is performed by the relative value of the detected temperature, without being affected by the initial concentration of the solution, A predetermined amount of ice storage can be obtained. Even if the temperature detector (Th) has variations, that is, even if the detected value of the temperature detector (Th) is higher or lower than the actual value, two detections are performed. Since it is controlled by the difference in value, an accurate amount of ice can be obtained without being affected by variations in the detector (Th).

In the freezing detection means (91) in the above embodiment, the freezing was detected by the temperature detected by the temperature detector (Th) becoming constant. In addition, as shown in FIG.
An optical sensor (OPS) for detecting the degree of turbidity of the solution may be provided in the return pipe (62) so that when the ice is generated, the transparency with the solution becomes dull, so that the freezing may be detected.

In addition, as shown in Fig. 8, the temperature of the solution becomes constant after freezing through the pressure detector (PS) that detects the evaporation pressure of the refrigerant that cools the solution, and the transfer of sensible heat to the transfer of latent heat. It is also possible to detect freezing by changing the evaporation pressure of the refrigerant to a substantially constant value as the temperature changes.

In addition, a drive motor (M that rotates the rotary drum (5)
It is also possible to detect freezing by the load torque fluctuation of 2).

(Effects of the Invention) As described above, in the present invention, the freezing detection means for detecting the start of freezing of the ice making solution in the inner pipe (2), and the temperature detector (Th) for detecting the outlet temperature of the inner pipe (2). , Storage means for storing the outlet temperature (T1) detected by the temperature detector (Th) when the start of freezing is detected by the freezing detection means, and the stored outlet temperature (T1) and the temperature detector (Th) after the start of freezing Based on the difference (T1-T2) from the detection outlet temperature (T2) by the compressor, a compressor start / stop means for controlling the start / stop of the compressor (8) for supplying the refrigerant for solution cooling is provided. The predetermined amount of ice storage can be obtained without being affected by variations in the initial concentration of the solution and the detection value of the temperature detector (Th).

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration block of a pipe system and an operation control device of the ice making device of the present invention, FIG. 2 is a diagram showing a control flow of the control device, and FIG. 3 is a diagram showing a change with time of a solution outlet temperature, FIG. 4 is a diagram showing the relationship between the solution concentration, the ice storage rate, and the freezing point, FIG. 5 is a partial cross-sectional side view of the evaporator for ice making, FIG. 6 is its longitudinal cross-sectional view, FIG. 7 and FIG. Are views showing other embodiments of the freezing detection means, respectively, and FIG. 9 is a piping system diagram of a conventional example. (1) …… Evaporator for ice making (2) …… Inner tube (3) …… Outer tube (5) …… Rotating drum (8) …… Compressor (Th) …… Temperature detector (91) …… Freezing detection means (92) …… Storage means (93) …… Compressor start / stop means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Kurata 1304 Kanaoka-machi, Sakai-shi, Osaka Daikin Industrial Co., Ltd., Kanaoka Plant, Sakai Manufacturing Co., Ltd. (56) Reference JP-A-64-46553 (JP, A) Kai 64-23075 (JP, A) JP 58-2567 (JP, A)

Claims (1)

(57) [Claims] 1. An evaporator (1) for ice-making, comprising a rotating drum (5) and an inner pipe (2) for circulating a solution for ice-making, and an outer pipe (3) for circulating a refrigerant for cooling the solution. ) And a compressor (8) for supplying the refrigerant to the outer pipe (3)
An operation control device in an ice making device having a refrigerating cycle having: a freezing detection means for detecting a freezing start of the solution in the inner pipe (2); and an outlet temperature of the inner pipe (2). Temperature detector (Th), storage means for storing the outlet temperature (T1) detected by the temperature detector (Th) when the start of freezing is detected by the freezing detection means, and the stored outlet temperature (T1) A compressor starting / stopping means for controlling starting / stopping of the compressor (8) based on a difference (T1-T2) between the temperature (T2) detected by the temperature detector (Th) after the start of freezing. The operation control device in the ice making device, which is characterized in that