JP2024035976A - Ultra-low temperature refrigeration system - Google Patents

Abstract

An object of the present invention is to provide an ultra-low temperature refrigeration system that can discharge frost formed in a defroster as it is. An ultra-low temperature refrigeration system 1 includes an ultra-low temperature freezer 10, an air refrigerant refrigerator 30 that cools air in the ultra-low temperature freezer and supplies cooled air to the ultra-low temperature freezer, and is provided in the ultra-low temperature freezer, It has a defroster 40 that removes frost from the air supplied from the air refrigerant refrigerator into the ultra-low temperature freezer. [Selection diagram] Figure 1

Description

TECHNICAL FIELD The present invention relates to ultra-low temperature refrigeration systems.

In recent years, in ultra-low temperature refrigerated warehouses, there has been a shift from binary refrigerators that use fluorocarbon refrigerants to air refrigerant refrigerators in order to reduce the use of fluorocarbon refrigerants as environmental measures and to save energy by reducing fan power.

Air refrigerant refrigerators use an air cycle that sucks in air from inside the warehouse, compresses it, and returns the cooled air to the inside of the warehouse through adiabatic expansion. Therefore, the moisture contained in the air turns into frost and accumulates inside the refrigerator and the warehouse, making it necessary to periodically defrost the inside of the refrigerator and the warehouse.

In connection with this, for example, Patent Document 1 below discloses an air refrigerant refrigerator in which a cyclone defrost device is installed in the front stage of the freezer. According to this configuration, the frost contained in the air cooled in the air refrigerant refrigerator is separated by the cyclone, and the amount of frost that enters the freezer is reduced. On the other hand, Patent Document 2 discloses defrosting using a net (filter section).

Japanese Patent Application Publication No. 2006-234275 Japanese Patent Application Publication No. 11-132583

In the above-mentioned configuration of Patent Document 1 (the defrost is outside the freezer), if the filter disclosed in Patent Document 2 is adopted as the defrost, since the defrost is installed outside the freezer, the ambient temperature If the temperature is relatively high, there is a risk that the frost will melt and plate-shaped ice will form on the filter section, causing the defrost device to become clogged and unable to defrost.

The present invention was invented in order to solve the above problems, and an object of the present invention is to provide an ultra-low temperature refrigeration system that can discharge frost that has formed on a defroster as it is.

The ultra-low temperature refrigeration system according to the present invention that achieves the above object includes an ultra-low temperature freezer that cools and stores objects to be cooled, and sucks and cools air in the ultra-low temperature freezer to supply the cooled air into the ultra-low temperature freezer. and a defrost device provided in the ultra-low temperature freezer to remove frost from the air supplied from the air refrigerant refrigerator into the ultra-low temperature freezer.

According to the above-mentioned ultra-low temperature refrigeration system, since the defrost device is provided in the ultra-low temperature freezer, it is possible to defrost in a low-temperature atmosphere, and the frost formed by the defrost device can be discharged as frost. Therefore, it is possible to suitably prevent frost from melting and plate-shaped ice from forming on the filter portion, which would clog the defrost device and make it impossible to defrost.

1 is a system diagram showing an ultra-low temperature refrigeration system according to an embodiment of the present invention. FIG. 2 is a diagram showing the defrost device of the ultra-low temperature refrigeration system according to the present embodiment, and is a diagram illustrating frost adhering to the filter section. FIG. 3 is a diagram showing the defrost device of the ultra-low temperature refrigeration system according to the present embodiment, and is a diagram illustrating how frost adhering to the filter part falls under its own weight. It is a figure showing a defrost concerning a modification. It is a system diagram showing an ultra-low temperature refrigeration system according to a modification.

Embodiments of the present invention will be described with reference to FIGS. 1 to 3. In addition, in the description of the drawings, the same elements are given the same reference numerals, and redundant description will be omitted. Dimensional proportions in the drawings are exaggerated for illustrative purposes and may differ from actual proportions.

FIG. 1 is a system diagram showing an ultra-low temperature refrigeration system 1 according to an embodiment of the present invention. FIG. 2 is a diagram showing the defrost device 40 of the ultra-low temperature refrigeration system 1 according to the present embodiment, and is a diagram showing frost adhering to the filter section 42. FIG. 3 is a diagram illustrating the defrost device 40 of the ultra-low temperature refrigeration system 1 according to the present embodiment, and is a diagram illustrating how frost adhering to the filter section 42 falls under its own weight.

The ultra-low temperature refrigeration system 1 according to this embodiment is used, for example, to cool a drug warehouse. Note that the object to be cooled is not limited to drug warehouses, but can also be used for cooling food warehouses and the like. As shown in FIG. 1, the ultra-low temperature refrigeration system 1 according to the present embodiment includes an ultra-low temperature freezer 10 for cooling and storing objects to be cooled, a circulation path 20 connected to the ultra-low temperature freezer 10 through which air circulates, and an interior of the ultra-low temperature freezer 10. An air refrigerant refrigerator 30 that supplies cooled air into the ultra-low temperature freezer 10 using air as a refrigerant; and an air refrigerant refrigerator 30 that supplies chilled air into the ultra-low temperature freezer 10 with It has a defrost device 40 for removing.

In the ultra-low temperature freezer 10, chemicals are cooled and stored as described above. In the ultra-low temperature freezer 10 where medicines are kept cooled, an automatic transport device is used to carry in and out the medicines unattended. If frost adheres to the automatic conveyance device, it may not function properly. Therefore, when using the air refrigerant refrigerator 30, the defrost device 40 removes the frost that adheres to the cooled air that returns to the ultra-low temperature freezer 10. must be removed.

Inside the ultra-low temperature freezer 10, an inlet (not shown) for air circulating through the circulation path 20 and an outlet (not shown) from which air cooled in the air refrigerant refrigerator 30 blows out are arranged. Although the internal temperature of the ultra-low temperature freezer 10 is not particularly limited, it is −50° C. or lower. In this way, since the temperature inside the ultra-low temperature freezer 10 is ultra-low, it is possible to prevent the frost from melting in the defrost device 40, and it is possible to suitably discharge the frost as it is. Further, when the internal temperature of the ultra-low temperature freezer 10 is -50° C. or lower, a certain amount of frost adhering to the filter section 42 will fall, so by removing the frost, continuous operation is possible.

When frost is formed in the air, the temperature of the moist air decreases and moisture in excess of the saturation amount precipitates out. Here, for example, when the temperature inside the refrigerator is higher than the temperature inside the ultra-low temperature freezer 10 according to the present embodiment, such as between -20°C and -30°C, the time when the droplets exist as supercooled droplets is long, and the liquid droplets freeze. It is easy to form large crystals by agglomeration and bonding before crystallization. On the other hand, since the internal temperature of the ultra-low temperature freezer 10 according to the present embodiment is -50°C or lower, supercooling is easily released and precipitates as ice before the mass increases, so that frost with small particle size can. Furthermore, since the absolute humidity is lower as the internal temperature of the ultra-low temperature freezer 10 is lower, the amount of moisture that precipitates decreases even with the same temperature difference, and a relatively small amount of frost is generated. Therefore, the frost adhering to the filter portion 42, which will be described later, becomes powdery and can be easily discharged from the defrost device 40 by wind pressure, as described later.

The air refrigerant refrigerator 30 includes a compressor 31, an expander 32, and a primary cooler 33, as shown in FIG. The compressor 31 and the expander 32 are integrated and connected to the same motor M. The air refrigerant refrigerator 30 constitutes a reverse Brayton cycle.

The cycle in the air refrigerant refrigerator 30 will be described below. Note that the temperature described below is an example and is not particularly limited.

First, the air in the ultra-low temperature freezer 10 (minus 60°C) that is sucked into the air refrigerant refrigerator 30 is compressed and heated in the compressor 31 to become high-temperature, high-pressure air at 90°C. The 90°C air is then cooled to 40°C in the primary cooler 33.

Next, the 40° C. air is adiabatically expanded in the expander 32 and cooled to -80° C., and this air is sent into the ultra-low temperature freezer 10.

Defrost device 40 is provided within ultra-low temperature freezer 10, as shown in FIG. For example, if the defrost is placed outside the freezer and the ambient temperature is relatively high, the frost may melt and form ice plates on the filter, causing the defrost to become clogged. There is a risk that it will become blocked and defrosting will not be possible. In contrast, the defrost device 40 according to the present embodiment is placed inside the ultra-low temperature freezer 10, so it can defrost in a low-temperature atmosphere and discharges the frost formed in the defrost device 40 as it is. be able to. Additionally, if the defrost is placed outside the freezer, for example, and the ambient temperature is relatively high, the frost may melt and form ice plates on the filter, causing the defrost to become clogged and blocked. As a result, there is a risk that defrosting will not be possible, so it is necessary to provide heat-insulating equipment, which may increase the size of the entire system. On the other hand, since the defrost device 40 according to the present embodiment is placed inside the ultra-low temperature freezer 10, it can defrost in a low-temperature atmosphere, eliminates the need for heat-insulating equipment, and can prevent the entire system from becoming larger.

In this embodiment, one defrost device 40 is provided. The defrost device 40 removes frost contained in the air when the air cooled to -80° C. is sent into the ultra-low temperature freezer 10 by the air refrigerant refrigerator 30. The configuration of the defrost device 40 will be described below, but the configuration of the defrost device 40 described below is an example, and the configuration of the defrost device 40 is not particularly limited.

As shown in FIGS. 2 and 3, the defrost device 40 includes a housing 41, a filter section 42 provided in the housing 41, and a first flow path through which air from which frost has been separated flows into the ultra-low temperature freezer 10. 43, a first valve 44 provided in the first flow path 43, a second flow path 45 through which frost passes when frost is discharged from the housing 41, and a second valve provided in the second flow path 45. 46.

The housing 41 is formed with a suction port 41A through which air containing frost cooled in the air refrigerant refrigerator 30 is sucked.

The filter portion 42 is attached with frost contained in the air sucked in from the suction port 41A, and separates the frost from the air. In this embodiment, the filter section 42 is arranged to extend in the horizontal direction, as shown in FIGS. 2 and 3. According to this configuration, since the filter portion 42 can be provided over a wide range, frost can be suitably attached to the filter portion 42.

The filter section 42 is configured to include countless voids. When the air containing frost passes through the filter section 42, the frost F adheres to the filter section 42, as shown in FIG. On the other hand, the air from which the frost has been separated passes through the filter section 42 and moves upward, and when the first valve 44 is open, it is sent into the ultra-low temperature freezer 10 via the first flow path 43 (Fig. (See arrow 2). That is, at this time, normal cooling operation is performed in the ultra-low temperature freezer 10.

If normal cooling operation is continued, when the amount of frost F adhering to the filter section 42 exceeds a predetermined value, it falls to the lower surface of the casing 41 due to its own weight, as shown in FIG. The fallen frost F is accumulated on the lower surface in a so-called powder state. Note that the defrost device 40 may further include a falling part that assists the frost adhering to the filter part 42 to fall due to its own weight. Although the falling part is not particularly limited, an ultrasonic vibrator or a blowing part that blows shot air can be used, but an ultrasonic vibrator is preferable from the viewpoint of preventing clogging in the filter part 42.

Furthermore, in order to assist the frost adhering to the filter part 42 from falling due to its own weight, the air flow may be reversed (downward in FIG. 2) to cause the frost adhering to the filter part 42 to fall.

When a predetermined amount of frost F has accumulated on the lower surface of the casing 41, as shown in FIG. The frost F can be discharged from the second flow path 45. That is, the first valve 44 and the second valve 46 function as a discharge section that discharges frost to the outside as it is. That is, at this time, in the ultra-low temperature freezer 10, normal cooling operation is stopped and defrosting operation is performed. Preferably, the second valve 46 is located within the ultra-low temperature freezer 10. Here, for example, if the second valve 46 is placed outside the ultra-low temperature freezer 10, there is a possibility that frost will melt and freeze inside the second valve 46. In this embodiment, the second valve 46 is placed inside the ultra-low temperature freezer 10, so that the above-mentioned freezing can be prevented.

The frost discharged outside the defrost device 40 is received by a drain pan, for example, and is melted and drained using a heater installed in the drain pan or warm air, thereby preventing re-sublimation and removing the frost. It can be easily done.

For example, if the defrost device 40 is not installed in the ultra-low temperature freezer 10 and the ambient temperature is relatively high, the frost attached to the filter section 42 will melt and ice will form on the filter section 42. There is a possibility that the defrost device 40 becomes clogged and cannot be defrosted.

On the other hand, in the ultra-low temperature refrigeration system 1 according to the present embodiment, the defrost device 40 is placed inside the ultra-low temperature freezer 10, so it can defrost in a low-temperature atmosphere, and removes the frost formed by the defrost device 40. It can be discharged as frost.

Note that a heater section may be attached to the filter section 42 of the defrost device 40. According to this configuration, even if frost adhering to the filter part 42 melts and plate-shaped ice forms on the filter part 42, the ice can be melted by the heater part, so that the defroster 40 can This prevents the defrosting from becoming impossible due to blockage.

Hereinafter, a defrosting method of the defrost device 40 of the ultra-low temperature refrigeration system 1 according to this embodiment will be explained. The defrosting method includes a suction process in which air with frost is sucked in from the suction port 41A of the housing 41, a separation process in which the frost is attached to the filter section 42 and separated from the air, and a step in which the frost is separated in the filter section 42. The process includes a step of sending the stored air into the ultra-low temperature freezer 10, and a discharge step of discharging the frost that has adhered to the filter part 42 and fallen under its own weight to the outside as frost. In the discharge step, with the first valve 44 closed and the second valve 46 opened, frost is discharged from the second flow path 45 by the wind pressure of the air sucked in from the suction port 41A.

As explained above, the ultra-low temperature refrigeration system 1 according to the present embodiment includes an ultra-low temperature freezer 10 that cools and stores objects to be cooled, and an ultra-low temperature freezer 10 that cools objects by sucking air inside the ultra-low temperature freezer 10. It has an air refrigerant refrigerator 30 that supplies air, and a defroster 40 that is provided in the ultra-low temperature freezer 10 and removes frost from the air supplied from the air refrigerant refrigerator 30 into the ultra-low temperature freezer 10. According to the ultra-low temperature refrigeration system 1 configured in this way, since the defrost device 40 is provided inside the ultra-low temperature freezer 10, it can be defrosted in a low-temperature atmosphere, and the frost formed by the defrost device 40 can be kept as frost. Can be discharged. Therefore, it is possible to suitably prevent frost from melting and forming ice, which would block the defrost device 40 and make it impossible to defrost.

The defrost device 40 also includes a suction port 41A through which air with frost is sucked in, a filter section 42 where frost is attached and which separates the frost from the air, and a filter section 42 in which the air from which the frost has been separated is kept at an extremely low temperature. It has a first flow path 43 that is sent into the freezer 10, and a discharge section that discharges the frost that falls under its own weight after frost adheres to the filter section 42 to the outside as frost. According to the ultra-low temperature refrigeration system 1 configured in this way, since a discharge section is provided, automatic defrosting becomes possible without an operator.

Moreover, the internal temperature of the ultra-low temperature freezer 10 is −50° C. or lower. According to the ultra-low temperature refrigeration system 1 configured in this way, since the temperature inside the ultra-low temperature freezer 10 is ultra low, it is possible to prevent the frost from melting in the defrost device 40 and to appropriately discharge the frost as it is. I can do it.

Although the present invention has been described above through the embodiments, the present invention is not limited to the embodiments and modifications described above, and can be variously modified within the scope of the claims.

For example, in the embodiment described above, the filter section 42 is arranged to extend in the horizontal direction, as shown in FIGS. 2 and 3. However, as shown in FIG. 4, the filter section 142 may be arranged to extend in the vertical direction. According to this configuration, frost can be efficiently attached to the filter portion 142 because it is arranged perpendicularly to the traveling direction of the air. Further, the number of filter sections 42, 142 provided may be provided in either the horizontal direction or the vertical direction, and is not limited to one.

Further, in the embodiment described above, one air refrigerant refrigerator 30 and one defrost device 40 were provided. However, as shown in FIG. 4, a plurality (three in FIG. 4) of the air refrigerant refrigerator 30 and the defroster 40 may be provided. At this time, if one of the three defrosters 40 is in defrosting operation, the other defrosters stop defrosting operation (normal operation), and the other defrosters stop defrosting operation. If it is in operation, the first defrost device stops defrosting operation (normal operation). According to this configuration, the inside of the ultra-low temperature freezer 10 can be continuously cooled while defrosting the defrost device 40 suitably.

Further, in the embodiment described above, the discharge section was configured by the first valve 44 and the second valve 46. However, the discharge section may be a conveyor or other conveyor placed on the bottom surface of the defrost device 40, and when a predetermined amount of frost accumulates on the conveyor, the conveyor discharges it out of the casing 41. It's okay.

1 Ultra-low temperature refrigeration system,
10 Ultra-low temperature freezer,
20 circulation path,
30 air refrigerant refrigerator,
31 Compressor,
32 Expander,
33 Primary cooler,
40 defrost,
41A Suction port,
42, 142 filter section,
43 first flow path,
44 first valve,
45 second flow path,
46 Second valve.

Claims (4)

An ultra-low temperature freezer that cools and stores items to be cooled;
an air refrigerant refrigerator that sucks and cools air in the ultra-low temperature freezer and supplies the cooled air to the ultra-low temperature freezer;
An ultra-low temperature refrigeration system comprising: a defrost device installed in the ultra-low temperature freezer to remove frost from the air supplied from the air refrigerant refrigerator into the ultra-low temperature freezer. A plurality of the defrosters are provided,
When one of the defrosters is in defrosting operation, the other defroster stops defrosting operation,
The ultra-low temperature refrigeration system according to claim 1, wherein when the other defrost device is in defrosting operation, the one defrost device stops defrosting operation. The defroster is
a suction port through which the frost-covered air is sucked;
a filter portion to which the frost adheres and separates the frost from the air;
a first flow path through which the air from which the frost has been separated in the filter section is sent into the ultra-low temperature freezer;
The ultra-low temperature refrigeration system according to claim 1 or 2, further comprising a discharge section that discharges the frost that has fallen under its own weight after the frost has adhered to the filter section to the outside as frost. The ultra-low temperature refrigeration system according to claim 1 or 2, wherein the internal temperature of the ultra-low temperature freezer is −50° C. or lower.