JPH0684859B2 - Ice machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ice making machine for sending ice cubes of several centimeters square, and in particular, prevention of cotton ice in a form of freezing ice while flowing raw water along an ice making plate. Regarding measures.

(Prior art) This type of ice machine freezes the raw water in a flowing state that flows down the ice-making surface of the ice-making plate. Collected ice pieces became so-called cotton ice, which clogged the pump that feeds the raw water to the ice making plate, causing malfunction and reducing the ice making capacity. Various proposals have been made in order to prevent the generation of such cotton ice, for example, the ice making device described in Japanese Utility Model Publication No. 61-12543.

(Problems to be Solved by the Invention) By the way, in order to freeze the flowing raw water, it is necessary to sufficiently absorb the heat of solidification from the raw water in the process of flowing down the ice making plate. If the heat of solidification is not sufficiently absorbed, freezing does not occur on the ice making surface even if the raw water temperature is cooled to around 0 ° C, and cotton ice is likely to occur in the raw water tank. Especially when the outside air temperature is high and the temperature of the refrigerant in the evaporation coil is not sufficiently lowered, cotton ice is often generated.

Based on the above facts, the present inventor reexamined the ice making process of the current ice making machine.

Currently, when a certain level of raw water is stored in the raw water tank,
The raw water pump is activated to pump up the raw water and let it flow down along the ice making plate. At this time, the water level in the raw water tank drops by the amount of the pumped up raw water, but this drop in water level is immediately supplemented by additional water supply, and the water level in the raw water tank can be replenished to the prescribed level required for one ice making operation. I am trying. In other words, with the current equipment, the raw water was additionally supplied immediately after the start of cooling the raw water, and thereafter, the raw water was not replenished until the ice making was completed and the water level in the raw water tank dropped to a certain level. .

This means that the water temperature in the raw water tank decreases almost uniformly as the icing progresses.
It was confirmed that cotton ice started to be generated when the water temperature in the tank dropped to, for example, about 2 ° C.

Figure 2 shows the data obtained from the experiment.
Fig. 2 (A) shows the temperature change curves during normal operation when cotton ice is generated, and Fig. 2 (B) shows the water temperature in the raw water tank and the dotted line shows the evaporation of the ice making plate. It shows the refrigerant temperature at the outlet. In FIG. 2 (A), the water temperature in the raw water tank drops rapidly at the start of the ice making operation. When the temperature of the raw water in the tank has dropped to around 2 ° C, the temperature of the refrigerant after heat exchange has dropped only to around minus 2 ° C because the outside air temperature is high.
For this reason, the absolute temperature difference between the raw water and the refrigerant is about 4 ° C when the plus 2 ° C raw water is supplied to the ice making surface and flows down.
However, even if the raw water temperature drops to 0 ° C as it flows down, it is not enough to absorb the heat of coagulation and the raw water temperature is almost 0 ° C.
As it was in the liquid state, it flowed down into the tank and the water temperature in the tank further dropped, and as a result, cotton ice was generated in the raw water tank. The V-shaped singular point P on the characteristic curve corresponds to the cotton ice generation site. The refrigerant temperature near the singular point P slightly rises from 0 ° C. to the positive side.

Even during the normal operation of FIG. 2 (B), a temperature change similar to that in the case of FIG. 2 (A) is followed until the water temperature in the raw water tank drops to 2 ° C. The decisive difference is that the water temperature in the tank changes smoothly to a stable temperature (1 ° C), and the singular point P does not appear. This is because icing on the ice making surface is smoothly performed and It is presumed that this is because the absorption is sufficient. In this case as well, the refrigerant temperature slightly rises due to the absorption of the heat of solidification, but the range of change is small, indicating that there is a margin in the cooling capacity of the refrigerant.

That is, in the current ice maker, when the temperature of the raw water in the tank has dropped to 2 ° C. or lower, it is presumed that the condition for producing cotton ice is satisfied if the cooling capacity of the refrigerant is insufficient.

The present invention has been proposed on the basis of the above findings, and it is an object of the present invention to reliably prevent the generation of cotton ice with a simple configuration and improve the ice making capacity.

(Means for Solving Problems) The present invention is directed to the case where the water temperature in the raw water tank during the ice making process is
Originally, it should be frozen to prevent abnormal decrease due to flowing raw water in a liquid state to prevent the production of cotton ice. Use raw water for additional water supply to prevent lowering of water temperature in the tank To do.

Specifically, in the early stage of the ice making process, the raw water tank is sent from the raw water tank through the raw water pump to the ice making plate, and the water level of the raw water tank is lowered by the amount of the circulating water flowing down to the raw water tank again.
This water level drop is not immediately replenished, but new raw water at room temperature is additionally supplied only after the water temperature in the raw water tank has dropped to around 0 ° C (for example, 2 ° C) to forcibly raise the raw water temperature in the tank. Of.

Specifically, as shown in FIG. 1, the solution means taken by the present invention comprises a raw water tank (6) for storing raw water and an ice making plate (4) arranged above the raw water tank (6). , A raw water pump (7) for feeding the raw water in the raw water tank (6) to the ice making plate (4), a water feed passage (11) for supplying new raw water to the raw water tank (6), and the water feed passage A raw water supply valve (12) for opening and closing (11). Further, a water level detector (13) for detecting the water level of the raw water in the raw water tank (6),
The raw water supplied from the raw water tank (6) to the ice making plate (4) receives the temperature detector (15) for detecting the temperature of the raw water, the water level detector (13) and the temperature detector (15). When the raw water level in the tank (6) is at the lower limit, the raw water supply valve (12) is opened to supply water, and when the raw water level reaches the upper limit, the raw water supply valve (12) is closed to start ice making. After the start, when the temperature of the raw water decreases to around 0 ° C, the raw water supply valve (12) is opened to control the additional water supply. Here, the temperature detector (15) is preferably provided in the raw water tank (6), but it is not always necessary, and in the raw water feed passage from the raw water tank (6) to the ice making plate (4). It may be provided anywhere.

(Operation) As a result, in the present invention, the water temperature of the raw water supplied to the ice making plate (4) is around 0 ° C. (for example, after water is supplied to the upper limit high water level in the raw water tank (6) to start ice making. Two
C.), new raw water at room temperature is replenished to the raw water tank (6) and the water temperature in the tank rises. Therefore, even if it flows down into the raw water tank (6) that has been cooled by the ice making plate (4) and could not be frozen, it cannot be frozen in the tank and no cotton ice is generated. After that, as the cooled raw water flows down, the temperature of the water in the tank gradually decreases, but during this decrease in the water temperature, the refrigerant temperature is also sufficiently reduced to reliably supply the cold heat necessary for freezing of the raw water. Cotton ice will not be produced until freezing.

(Effects of the Invention) As described above, according to the ice-making machine of the present invention, when the inside and outside conditions where cotton ice is likely to be generated start to be satisfied, new raw water at room temperature is supplied to the raw water tank to solidify. Even if raw water that has just cooled to the critical state flows down into the raw water tank, the rise in the temperature of the raw water in the tank can prevent icing, so it is possible to reliably prevent cotton ice from forming and improve the ice making capacity. It became possible.

In addition, since the raw water temperature is detected by the temperature detector and the raw water supply valve is opened based on the temperature detection signal to add new raw water, it is not necessary to make a major change in the ice making machine. Some are advantageous in that they can be easily applied to existing ice machines.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 shows the principle structure of an ice making machine. (1) is a cooling device and (2) is a raw water circulation device.

The cooling device (1) includes a compressor (3), a condenser (5),
An expansion mechanism (9), an ice making plate (4) consisting of a flat plate evaporator, and an accumulator (10) are provided, and devices other than the ice making plate (4) are different from the raw water circulation device (2). It is housed in a ward room.

The raw water circulation device (2) has a raw water tank (6) for storing a certain amount of raw water for ice making, and the raw water pump (7) pumps raw water from the raw water tank (6) to a sprinkling tank (8).
Raw water is supplied from above to the ice making plate (4) through the water spray nozzle (8a) of the water spray tank (8). The ice making plate (4) is arranged so that the lower end edge thereof is located above the raw water tank (6), and the raw water ejected from the sprinkling nozzle (8a) is caused to flow down along the ice making surface of the ice making plate (4). , Return to the raw water tank (6).

Fresh raw water at room temperature is supplied to the raw water tank (6) through the water supply channel (11). The water supply channel (11) is opened and closed by a raw water supply valve (12) which is an electromagnetic valve provided in the middle of the water channel.
The raw water supply valve (12) is opened and closed by a control device (16) which receives a water level detection signal from a water level detector (13) provided in the raw water tank (6), and sends it when the water level in the tank reaches a predetermined low water level. Water is supplied by opening the water channel (11), and when the water level in the tank reaches a predetermined high water level, the water channel (11) is shut off to stop water supply. The raw water between the set low water level and high water level is the amount of water required for one ice making. (14) is an overflow pipe.

The raw water pressurized in the raw water tank (7) is ejected from the water spray nozzle (8a) and is cooled while flowing down along the ice making surface of the ice making plate (4). At this time, the water level of the raw water tank (6) falls below the high water level by an amount corresponding to the amount of water circulating between the raw water tank (6) and the ice making plate (4). Replenishment of new raw water for this lowered water level will be performed later.

When the raw water temperature on the ice making surface of the ice making plate (4) and the temperature of the refrigerant passing through the evaporation coil (4a) of the ice making plate (4) reach predetermined values, freezing occurs on the ice making surface. The water temperature in the raw water tank (6) gradually decreases with the progress of freezing.
In order to prevent the generation of cotton ice due to the decrease in the water temperature in the tank, the above-mentioned new raw water is replenished when the water temperature becomes around 0 ° C, for example, 2 ° C or less.

Specifically, a temperature detector (15) for the raw water tank (6) is attached, and the temperature detector (15) is set to emit a detection signal when the water temperature in the tank drops to 2 ° C. The received control device (16) controls the opening of the raw water supply valve (12). As a result, new raw water having almost the same temperature as the outside air temperature is supplied to the raw water tank (6), so that the water temperature in the tank rises rapidly. For example, when new raw water at 35 ° C is additionally supplied, the water temperature in the tank rises to approximately 8 ° C. Therefore, even if the raw water enters the tank in the water state of 0 ° C without completely dissipating the heat of solidification when flowing down the ice making surface of the ice making plate (4), the water temperature in the tank is sufficiently high, The raw water does not freeze and no cotton ice is produced.
After that, the water temperature in the tank gradually decreases again, but it takes some time for the water temperature in the tank to drop to 2 ° C again, during which the refrigerant temperature in the evaporation coil (4a) absorbs the heat of solidification sufficiently. Since the water is reduced and restored to the extent that it can be obtained, raw water in a critical state on the verge of solidification can be reliably frozen on the ice making surface side.

When the water level in the tank reaches a low water level, the control device (16) that receives the signal stops the operation of the raw water pump (7), and the hot gas bypass passage (18) becomes hot due to the electromagnetic valve (19). The gas is forcibly separated from the ice making surface of the ice making plate (4) and drops as ice cubes.

(Modification) In the above embodiment, the raw water tank (6) is changed to the ice making plate (4).
A temperature detector (15) for detecting the temperature of the raw water sent to the raw water tank (6) was attached to the raw water tank (6), but it is not always necessary, and the raw water tank (6) to the raw water pump (7) and the sprinkling tank (8) are not necessarily required. It may be provided anywhere in the raw water supply path (17) that leads to the starting end under the raw water flow at the upper end of the ice making plate (4).

Further, the arrangement structure of the ice making plate (4) and the raw water tank (6) can be applied not only to the configuration described in the embodiment but also to the ice making plate (4) which is vertical.

Further, the temperature rise of the water temperature in the tank due to the addition of new raw water may be unnecessary depending on the temperature of the refrigerant in the ice making plate.
Therefore, the refrigerant temperature or the outside air temperature may be added as one of the conditions, and the additional water supply may be performed in association with the water temperature in the tank only under the condition that cotton ice is likely to be generated.

[Brief description of drawings]

FIG. 1 is a principle diagram of an ice making machine according to an embodiment of the present invention.
2A and 2B are temperature characteristic curve diagrams showing the correlation between the raw water tank water temperature and the refrigerant temperature in the comparative example. (4) …… Ice plate, (6) …… Raw water tank, (7) ……
Raw water pump, (11) …… water supply channel, (12) …… raw water supply valve, (13) …… water level detector, (15) …… temperature detector,
(16) …… Control device.

Claims (1)

[Claims] 1. A raw water tank (6) for storing raw water, an ice making plate (4) arranged above the raw water tank (6), and raw water in the raw water tank (6) for making an ice making plate (4). And a raw water supply valve (12) for opening and closing the water supply passage (11), and a raw water pump (7) for supplying the raw water to the raw water tank (6). , A water level detector (13) for detecting the water level of the raw water in the raw water tank (6)
And a temperature detector (15) for detecting the temperature of the raw water fed from the raw water tank (6) to the ice making plate (4), and the outputs of the water level detector (13) and the temperature detector (15). When the raw water level in the raw water tank (6) is at the lower limit, the raw water supply valve (12) is opened to supply water, and when the raw water level reaches the upper limit, the raw water supply valve (12) is closed to start ice making. ,
An ice making machine comprising: a control device (16) for controlling the raw water supply valve (12) to be opened to supply additional water when the temperature of the raw water has dropped to around 0 ° C after the start of ice making.