TECHNICAL FIELD
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The present invention relates to a defroster and a defrosting method.
BACKGROUND ART
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Recently, at ultralow-temperature refrigerated warehouses, transition from a two-stage refrigerator using a Freon refrigerant to an air-refrigerant refrigerator has been made to achieve energy saving through Freon refrigerant reduction and fan power reduction by environment measures (for example,
JP 2006-234275 A ).
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The air-refrigerant refrigerator employs an air cycle that sucks air in the warehouse, compresses the air, and returns the air cooled through adiabatic expansion to the warehouse. Accordingly, water contained in the air becomes frost and accumulates in the refrigerator and the warehouse, and thus defrosting needs to be periodically performed in the refrigerator and the warehouse.
SUMMARY OF INVENTION
Technical Problem
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A defroster of
JP 2006-234275 A described above is installed outside a warehouse, and thus when ambient temperature is relatively high, frost melts and plate-shaped ice forms at a filter component, and as a result, the defroster potentially becomes blocked due to clogging and unable to defrost.
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The present invention has been made to solve the above-described problem, and an object of the present invention is provide a defroster and a defrosting method that are capable of discharging accumulated frost on the defroster in frost form. Means for Solving Problem
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A defroster according to the present invention that achieves the above-described object includes a suction port through which air with adhered frost is sucked; a filter component to which the frost adheres and that separates the frost from the air; a first flow path through which the air, from which the frost is separated by the filter component, is transferred into an ultralow-temperature warehouse; and a discharge component that externally discharges the frost that has dropped from the filter component.
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A defrosting method according to the present invention that achieves the above-described object includes a suction step of sucking air with adhered frost through a suction port; a separation step of causing adhesion of the frost to a filter component and separating the frost from the air; a step of transferring the air, from which the frost is separated by the filter component, into an ultralow-temperature warehouse; and a discharge step of externally discharging the frost that has dropped from the filter component.
Advantageous Effect of the Invention
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According to the defroster and the defrosting method described above, dropped frost can be externally discharged in frost form by the discharge component. Thus, it is possible to excellently prevent a situation in which frost melts and plate-shaped ice forms at the filter component, and as a result, the defroster becomes blocked due to clogging and unable to defrost.
BRIEF DESCRIPTION OF DRAWINGS
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- Fig. 1 is a system diagram illustrating an ultralow-temperature refrigeration system including a defroster according to an embodiment of the present invention.
- Fig. 2 is a diagram illustrating the defroster according to the present embodiment in a state in which frost adheres to a filter component.
- Fig. 3 is a diagram illustrating the defroster according to the present embodiment in a state in which frost adhering to the filter component has dropped due to its own weight.
- Fig. 4 is a diagram illustrating a defroster according to Modification 1.
- Fig. 5 is a diagram illustrating a defroster according to Modification 2.
- Fig. 6A is a diagram illustrating a defroster according to Modification 3 in a state in which the filter component is disposed inside the defroster.
- Fig. 6B is a diagram illustrating the defroster according to Modification 3 in a state in which the filter component is disposed outside the defroster.
- Fig. 7A is a diagram illustrating a defroster according to Modification 4 in a state in which the filter component is disposed inside the defroster.
- Fig. 7B is a diagram illustrating the defroster according to Modification 4 in a state in which the filter component is disposed outside the defroster.
DESCRIPTION OF EMBODIMENTS
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An embodiment of the present invention will be described below with reference to Figs. 1 to 3. Note that any same element in description of the drawings is denoted by the same reference sign and duplicate description thereof is omitted. The dimensional ratios of the drawings are exaggerated for convenience of description and different from actual ratios in some cases.
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Fig. 1 is a system diagram illustrating an ultralow-temperature refrigeration system 1 including a defroster 40 according to the embodiment of the present invention. Fig. 2 is a diagram illustrating the defroster 40 according to the present embodiment in a state in which frost adheres to a filter component 42. Fig. 3 is a diagram illustrating the defroster 40 according to the present embodiment in a state in which frost adhering to the filter component 42 has dropped due to its own weight.
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The ultralow-temperature refrigeration system 1 is used to cool, for example, a drug warehouse. Note that a cooling target is not limited to a drug warehouse but may be a food warehouse or the like. As illustrated in Fig. 1, the ultralow-temperature refrigeration system 1 includes an ultralow-temperature warehouse 10 in which a cooling target object is cooled and stored, a circulation path 20 that is connected to the ultralow-temperature warehouse 10 and through which air circulates, an air-refrigerant refrigerator 30 that supplies cooled air into the ultralow-temperature warehouse 10 by using air in the ultralow-temperature warehouse 10 as a refrigerant, and the defroster 40 that removes frost in air supplied from the air-refrigerant refrigerator 30 into the ultralow-temperature warehouse 10.
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Drugs are cooled and stored in the ultralow-temperature warehouse 10 as described above. An automatic conveyance device is used to perform unmanned conveyance of drugs into and out of the ultralow-temperature warehouse 10 where drugs are cooled and stored. The automatic conveyance device potentially does not normally operate when frost adheres to the automatic conveyance device, and thus frost adhering to cooled air returning into the ultralow-temperature warehouse 10 needs to be removed by the defroster 40 when the air-refrigerant refrigerator 30 is used.
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A suction port (not illustrated) for air circulating through the circulation path 20 and a blowoff port (not illustrated) through which air cooled by the air-refrigerant refrigerator 30 is blown out are disposed inside the ultralow-temperature warehouse 10. The internal temperature of the ultralow-temperature warehouse 10 is not particularly limited but is equal to or lower than -50°C. Since the internal temperature of the ultralow-temperature warehouse 10 is such an ultralow temperature, frost can be prevented from melting at the defroster 40 and can be excellently discharged in frost form. Moreover, when the internal temperature of the ultralow-temperature warehouse 10 is equal to or lower than -50°C, frost adhering to the filter component 42 drops as the amount of the frost reaches a certain amount, and thus continuous operation can be performed by removing the frost.
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When frost is generated in air, the temperature of air containing water decreases and water in an amount exceeding a saturated amount deposits. For example, in a case of an internal temperature of -20°C to -30°C, which is higher than the internal temperature of the ultralow-temperature warehouse 10 according to the present embodiment, water exists as supercooling droplets for a long time and is likely to form large crystals through flocculation and coupling before freezing. However, since the internal temperature of the ultralow-temperature warehouse 10 according to the present embodiment is -60°C to -50°C, supercooling is likely to be released and water deposits as ice before mass increases, and thus frost is generated in a small particle size. Moreover, as the internal temperature of the ultralow-temperature warehouse 10 decreases, absolute humidity decreases and the amount of depositing water for the same temperature difference decreases, and accordingly, relatively small frost is generated. Thus, frost adhering to the filter component 42 to be described later is in powder form and can be easily discharged from inside the defroster 40 with wind pressure as described later.
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As illustrated in Fig. 1, the air-refrigerant refrigerator 30 includes a compressor 31, an expander 32, and a primary cooler 33. 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.
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The cycle of the air-refrigerant refrigerator 30 will be described below. Note that temperatures described below are exemplary and the present invention is not limited thereto.
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First, air in the ultralow-temperature warehouse 10 (-60°C), which is sucked into the air-refrigerant refrigerator 30 is compressed and heated at the compressor 31 and becomes high-temperature and high-pressure air at 90°C. Then, the air at 90°C is cooled to 40°C at the primary cooler 33.
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Subsequently, the air at 40°C is adiabatically expanded and cooled to -80°C at the expander 32, and the air is transferred into the ultralow-temperature warehouse 10.
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In the present embodiment, the defroster 40 is provided in the ultralow-temperature warehouse 10 as illustrated in Fig. 1, but the position where the defroster 40 is disposed is not limited. However, the defroster 40 is preferably disposed downstream of the expander 32 in the air-refrigerant refrigerator 30.
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In the present embodiment, one defroster 40 is provided. The defroster 40 removes frost contained in air cooled to -80°C by the air-refrigerant refrigerator 30 when the air is transferred into the ultralow-temperature warehouse 10. The configuration of the defroster 40 will be described below.
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As illustrated in Figs. 2 and 3, the defroster 40 includes a housing 41, the filter component 42 provided in the housing 41, a first flow path 43 through which air, from which frost is separated, is circulated into the ultralow-temperature warehouse 10, a first valve 44 provided in the first flow path 43, a second flow path 45 through which frost passes when discharged from the housing 41, and a second valve 46 provided in the second flow path 45.
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A suction port 41A through which air cooled at the air-refrigerant refrigerator 30 and containing frost is sucked is formed at the housing 41.
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Frost contained in air sucked through the suction port 41A adheres to the filter component 42 and is separated from the air. In the present embodiment, the filter component 42 is disposed to extend horizontally as illustrated in Figs. 2 and 3. With this configuration, the filter component 42 can be provided across a broad range and thus frost can excellently adhere to the filter component 42.
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The filter component 42 includes numerous void spaces. Frost F adheres to the filter component 42 as illustrated in Fig. 2 when air containing the frost passes through the filter component 42. Air from which frost is separated moves upward through the filter component 42 and is transferred into the ultralow-temperature warehouse 10 through the first flow path 43 (refer to arrows in Fig. 2) in a case where the first valve 44 is opened. Accordingly, normal cooling operation is performed in the ultralow-temperature warehouse 10 in this case.
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As normal cooling operation continues, frost F adhering to the filter component 42 drops onto the lower surface of the housing 41 due to its own weight as illustrated in Fig. 3 when its amount becomes equal to or larger than a predetermined amount. The dropped frost F accumulates on the lower surface in what is called a powder state. Note that the defroster 40 may further include a dropping component that assists dropping of frost adhering to the filter component 42 due to its own weight. The dropping component is not particularly limited and may be an ultrasonic vibrator or a blowoff component that blows shot air, but is preferably an ultrasonic vibrator from the viewpoint of preventing clogging of the filter component 42.
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Moreover, to assist dropping of frost adhering to the filter component 42 due to its own weight, air flowmaybe inverted (downward in Fig. 2) to drop the frost adhering to the filter component 42.
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Once a predetermined amount of frost F accumulates on the lower surface of the housing 41, frost F can be discharged through the second flow path 45 with wind pressure of air sucked through the suction port 41A in a state in which the first valve 44 is closed and the second valve 46 is opened as illustrated in Fig. 3. Accordingly, the first valve 44 and the second valve 46 function as a discharge component that externally discharges frost in frost form. Specifically, normal cooling operation is stopped and defrosting operation is performed in the ultralow-temperature warehouse 10 in this case. The second valve 46 is preferably disposed inside the ultralow-temperature warehouse 10. Frost potentially melts and forms ice in the second valve 46, for example, in a case where the second valve 46 is disposed outside the ultralow-temperature warehouse 10. In the present embodiment, the above-described ice formation can be prevented since the second valve 46 is disposed inside the ultralow-temperature warehouse 10.
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Frost discharged to the outside of the defroster 40 is received by, for example, a drain pan, melted by a heater installed in the drain pan, hot air, or the like, and discharged as water to prevent resublimation and facilitate frost removal work.
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Since the defroster 40 according to the present embodiment is disposed inside the ultralow-temperature warehouse 10, defrosting can be performed in a low-temperature atmosphere and accumulated frost on the defroster 40 can be excellently discharged in frost form.
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Note that a heater component may be attached to the filter component 42 of the defroster 40. With this configuration, even when frost adhering to the filter component 42 melts andplate-shaped ice forms at the filter component 42, the ice can be melted by the heater component and thus the defroster 40 can be prevented from becoming blocked and unable to defrost.
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A defrosting method for the defroster 40 of the ultralow-temperature refrigeration system 1 according to the present embodiment will be described below. The defrosting method includes a suction step of sucking air with adhered frost through the suction port 41A of the housing 41; a separation step of causing adhesion of the frost to the filter component 42 and separating the frost from the air; a step of transferring the air, from which the frost is separated by the filter component 42, into the ultralow-temperature warehouse 10; and a discharge step of externally discharging the frost that has dropped from the filter component 42. In the discharge step, the frost is discharged through the second flow path 45 with wind pressure of the air sucked through the suction port 41A in a state in which the first valve 44 is closed and the second valve 46 is opened.
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As described above, the defroster 40 according to the present embodiment includes the suction port 41A through which air with adhered frost is sucked; the filter component 42 to which the frost adheres and that separates the frost from the air; the first flow path 43 through which the air, from which the frost is separated by the filter component 42, is transferred into the ultralow-temperature warehouse 10; and the discharge component that externally discharges the frost that has dropped from the filter component 42. According to the defroster 40 thus configured, frost can be externally discharged in frost form by the discharge component. Thus, it is possible to excellently prevent a situation in which frost melts and plate-shaped ice forms at the filter component 42, and as a result, the defroster 40 becomes blocked due to clogging and unable to defrost.
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The defroster 40 further includes the second flow path 45 through which frost adhering to the filter component 42 is discharged; the first valve 44 provided in the first flow path 43; and the second valve 46 provided in the second flow path 45, and the discharge component discharges the frost with wind pressure of air sucked through the suction port 41A in a state in which the first valve 44 is closed and the second valve 46 is opened. According to the defroster 40 thus configured, it is possible to perform unmanned automatic defrosting.
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The filter component 42 is disposed to extend horizontally. According to the defroster 40 thus configured, the filter component 42 can be provided across a broad range and thus frost can excellently adhere to the filter component 42.
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The defroster 40 further includes the dropping component that drops frost adhering to the filter component 42. According to the defroster 40 thus configured, it is possible to more excellently prevent clogging of the filter component 42.
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The defroster 40 further includes the heater component attached to the filter component 42. According to the defroster 40 thus configured, even when frost adhering to the filter component 42 melts and plate-shaped ice forms at the filter component 42, the ice can be melted by the heater component and thus the defroster 40 can be prevented from becoming blocked and unable to defrost.
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Although the present invention is described above with reference to the embodiment, the present invention is not limited to the above-described embodiment and modifications but may be modified in various manners in the range of the claims.
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For example, the filter component 42 is disposed to extend horizontally as illustrated in Figs. 2 and 3 in the above-described embodiment. However, a filter component 142 may be disposed to extend vertically as illustrated in Fig. 4. With this configuration, the filter component 142 is disposed in a direction orthogonal to the traveling direction of air, and thus it is possible to efficiently cause adhesion of frost to the filter component 142. Alternatively, a filter component 242 may be disposed at a tilt to the horizontal and vertical directions as illustrated in Fig. 5.
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One filter component 42 is provided in the above-described embodiment. However, a plurality (in Fig. 6A, three) of filter components 42 may be provided in the vertical direction as illustrated in Figs. 6A and 6B. In a case where a plurality of filter components 42 are provided in the vertical direction, part of the housing 41 can be opened and closed so that any filter component 42 to which frost F adheres can be taken out as illustrated in Fig. 6B.
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One filter component 142 is provided in the above-described embodiment. However, a plurality (in Fig. 7A, nine) of filter components 142 may be provided in the horizontal direction as illustrated in Figs. 7A and 7B. In a case where a plurality of filter components 142 are provided in the horizontal direction, part of the housing 41 can be opened and closed so that any filter component 142 to which frost F adheres can be taken out as illustrated in Fig. 7B.
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The discharge component is constituted by the first valve 44 and the second valve 46 in the above-described embodiment. However, the discharge component may be a conveyance device such as a conveyer disposed on the lower surface of the defroster 40 so that frost is discharged to the outside of the housing 41 by the conveyance device once a predetermined amount of frost accumulates on the conveyance device.
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The present application is based on
Japanese Patent Application No. 2022-140646 filed on September 5, 2022 , and the entire contents of which are incorporated herein by reference. Reference Signs List
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- 1: ultralow-temperature refrigeration system
- 10: ultralow-temperature warehouse
- 20: circulation path
- 30: air-refrigerant refrigerator
- 31: compressor
- 32: expander
- 33: primary cooler
- 40: defroster
- 41A: suction port
- 42, 142, 242: filter component
- 43: first flow path
- 44: first valve
- 45: second flow path
- 46: second valve