Cooling storage

Abstract

To inexpensively suppress a situation where melted frost on a cooler is scattered in a storage chamber.SOLUTION: In a cooling operation for cooling a storage chamber 12, when a door sensor 14 detects that a door 13 is opened, a control unit 17 of a cooling storage 10 stops a circulation fan 30 if it is in operation, continues a stop state if it is stopped, and performs first determination when the door sensor 14 detects that the opened door 13 is closed. The first determination is whether or not the opening time of the door 13 is equal to or longer than a threshold time, or whether or not the detected temperature of the cooler temperature sensor 35 is equal to or higher than a first threshold temperature. When the opening time is equal to or longer than the threshold time, or when the detected temperature is equal to or higher than the first threshold temperature, the control unit 17 re-operates the stopped circulation fan 30 at a low speed in the variable range.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present technology relates to refrigerated storage. [Background technology]

[0002] There is known a technology for controlling the operation of an internal fan that circulates air inside a refrigerated storage cabinet in response to the opening and closing of the door, and one example of this technology is described in Patent Document 1. The refrigerated storage cabinet described in Patent Document 1 stops the internal fan when the door is opened and the internal temperature abnormally falls outside the temperature retention range. This is said to prevent the cold air inside the cabinet from actively mixing with the warm air outside the cabinet, thereby suppressing the rise in the internal temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-88667 Summary of the Invention [Problem to be solved by the invention]

[0004] The control described in Patent Document 1 can prevent excessive increases in the temperature inside the refrigerator when the door is opened. However, a certain degree of temperature rise still occurs, and if the door is left open for a long time before being closed, the frost on the cooler (heat exchanger) may melt. This melted frost (melt water) may be scattered throughout the storage compartment by the wind force of the interior fan when the interior fan is restarted. As a result, the melt water may adhere to the stored items inside the storage compartment or fall onto the floor of the storage compartment, wetting it. However, installing ducts or other devices to prevent the scattering of melt water increases costs.

[0005] This technology was developed based on the above-mentioned circumstances, and aims to prevent the situation in which melted ice water from the cooler splashes into the storage room at low cost. [Means for solving the problem]

[0006] In order to solve the above problems, a refrigerated storage cabinet according to the present technology includes a storage cabinet body having an opening and a storage chamber into and out of which stored items are put through the opening, a door that opens and closes the opening, a cooling device that cools the storage chamber, a circulation fan that circulates air within the storage chamber so that air that has been sucked in from the storage chamber and cooled by a cooler constituting the cooling device is returned to the storage chamber, the circulation fan having a variable rotation speed, a door sensor that detects whether the door is open or closed, a cooler temperature sensor that detects the temperature of the cooler, and a control unit, During cooling operation to cool the storage compartment, when the door sensor detects that the door has been opened, the control unit stops the circulation fan if it is operating, or keeps it stopped if it is stopped, and when the door sensor detects that the open door has been closed, the control unit makes a first determination, the first determination being whether the open time from when the door was opened to when it was closed is equal to or greater than a threshold time, or whether the detected temperature of the cooler temperature sensor is equal to or greater than a first threshold temperature, and if, as a result of the first determination, the open time is equal to or greater than the threshold time, or if the detected temperature is equal to or greater than the first threshold temperature, the control unit restarts the stopped circulation fan at a low speed within its variable range.

[0007] Furthermore, the control unit may perform a second determination after restarting the circulation fan at the low speed, the second determination being whether or not the detected temperature of the cooler temperature sensor is less than a second threshold temperature, and if the result of the second determination is that the detected temperature is equal to or greater than the second threshold temperature, the control unit may keep the speed of the circulation fan at the low speed, and if the detected temperature is less than the second threshold temperature, may increase the speed of the circulation fan to a high speed greater than the low speed.

[0008] Furthermore, the control unit may perform the second determination after counting the passage of a predetermined time after restarting the circulation fan at the low speed. [Effects of the Invention]

[0009] According to this technology, it is possible to prevent the melted ice water from the cooler from splashing into the storage room at low cost. [Brief explanation of the drawings]

[0010] [Figure 1] Partially cutaway perspective view of a prefabricated refrigerator according to the first embodiment [Figure 2] Schematic cross-sectional view of the indoor unit [Figure 3] Flowchart showing the process of opening and closing the door of the interior fan [Figure 4] 10 is a flowchart showing a process performed when the door of the internal fan is opened or closed according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment 1> A refrigerated storage cabinet 10 according to the first embodiment will be described with reference to Figures 1 to 3. The symbols F, B, L, R, U, and D shown in some of the drawings respectively indicate the front and rear in the front-to-rear direction of the refrigerated storage cabinet 10, the left and right in the width direction (left-right direction) when viewed from the front, and the top and bottom in the vertical direction (up-down direction).

[0012] As shown in FIG. 1 , the refrigerated storage cabinet 10 mainly comprises a storage cabinet main body 11, an insulated door 13, a cooling device 20 for cooling a storage chamber 12 that occupies most of the interior space of the storage cabinet main body 11, a control unit 17, and an operation unit 18. The storage cabinet main body 11 is an insulated box body formed by assembling insulated walls into a box shape and has a front opening 11S. The door 13 is attached to the front wall of the storage cabinet main body 11 so that the front opening 11S can be swung open and closed. The refrigerated storage cabinet 10 also has a door sensor 14 located near the upper edge of the front opening 11S that detects whether the door 13 is open or closed. The type of door sensor 14 is not limited, but it can be, for example, a proximity switch that responds to a magnet embedded in the door 13. If the door sensor 14 is a proximity switch, the switch turns on and off depending on whether the door 13 is open or closed.

[0013] The front opening 11S and the door 13 according to this embodiment are large enough for a person to enter and exit to take stored items in and out, and the refrigerated storage facility 10 is a prefabricated refrigerated storage facility with a large storage room 12. However, this technology can also be applied to refrigerated storage facilities other than prefabricated facilities that are not large in size.

[0014] An indoor unit 15, which incorporates a cooler 25 and an interior fan 30 (an example of a circulation fan) described below, is disposed within the storage body 11 (hereinafter sometimes referred to as the interior) in a manner that it is suspended from the ceiling wall 11A of the storage body 11. Most of the interior of the storage body 11, excluding the space where the indoor unit 15 is disposed, constitutes the storage chamber 12. An outdoor unit 16, connected to the cooler 25 by refrigerant piping 29, is disposed outside the storage body 11 (hereinafter sometimes referred to as the exterior). The outdoor unit 16 includes at least a compressor 27 and an air-cooled condenser 28. The cooler 25, compressor 27, and condenser 28 are connected by refrigerant piping 29 to form a known refrigeration circuit, constituting the cooling device 20. The cooler 25 is a fin-tube heat exchanger. The cooling device 20 is also assumed to be appropriately equipped with a dryer and the like.

[0015] The control unit 17 is configured with a control board including a CPU, a microcomputer, etc., and controls the operation of the cooling storage cabinet 10. The control unit 17 is equipped with memories such as ROM and RAM, and has a time counting function (timer). The operation unit 18 is provided to allow the user to change various settings of the cooling storage cabinet 10 and select an operation mode.

[0016] As shown in Fig. 2, the indoor unit 15 includes a cooler 25, an internal fan 30, a cooler temperature sensor 35, an internal temperature sensor 36, a defrosting heater 37, and a casing 38 in which these components are housed and attached. The casing 38 has a rectangular parallelepiped shape that is elongated in the front-to-rear direction, and an air inlet 38A for the storage chamber 12 is formed over almost the entire surface of one side surface (the right side in Fig. 2).

[0017] Cooler 25 is disposed on the side of suction port 38A inside casing 38. An internal temperature sensor 36 (e.g., a thermistor) is attached near suction port 38A to detect the temperature of the air in storage chamber 12 flowing into cooler 25. Casing 38 also serves as a drain pan to receive defrosted water that drops from cooler 25. The bottom surface of casing 38 is inclined, and drain port 38B is provided at the lower edge of the bottom surface to which drain hose 39 (see FIG. 1) is connected.

[0018] The interior fan 30 is provided inside the casing 38 on the opposite side of the air inlet 38A, and is disposed adjacent to the cooler 25. The interior fan 30 includes a main body 31 that rotates when driven by a motor, and a fan cover 32 that covers the main body 31. The rotation speed of the main body 31 is variable depending on the output value of the motor, and the speed can be changed to at least two stages: high speed and low speed. The high speed of the main body 31 of the interior fan 30 according to this embodiment is set to a speed at which the motor output is at its maximum, and the low speed is set to a value lower than the maximum motor output.

[0019] The fan cover 32 of the internal fan 30 is attached so as to cover an opening 38C on the other side (the left side in FIG. 2 ) of the casing 38. A vent hole is formed in the fan cover 32, which serves as an outlet 32A for cold air to be blown into the storage chamber 12. The fan cover 32 may be formed as a part of the casing 38, and the outlet 32A may be a vent hole formed in the casing 38.

[0020] Main body 31 of internal fan 30 rotates to draw in cool air from cooler 25 and blow the drawn-in cool air out of outlet 32A. Therefore, internal fan 30 circulates air in storage chamber 12 such that air is drawn from storage chamber 12 through inlet 38A into cooler 25, cooled by cooler 25, and then blown out of outlet 32A and returned to storage chamber 12.

[0021] Defrosting heater 37 heats and melts frost adhering to cooler 25 and the like during defrosting operation, which will be described later. Defrosting heater 37 is, for example, a sheathed heater, and is attached to the surface of cooler 25 on the side of inlet 38A and to the bottom surface. More specifically, defrosting heater 37 is fitted into grooves 25A formed by cutting out the edges of the fins and end plates of cooler 25, and is disposed so as to be wound in a serpentine shape.

[0022] The cooler temperature sensor 35 (e.g., a thermistor) detects the temperature of the cooler 25. The cooler temperature sensor 35 according to this embodiment is provided at a position away from the air inlet 38A side (air inflow side) of the cooler 25, for example, by being attached to an end plate of the cooler 25. The location of the cooler temperature sensor 35 is not particularly limited as long as it can detect the temperature of the cooler 25.

[0023] Next, the operation control of the refrigerated storage cabinet 10 configured as described above will be described. The control unit 17 executes a cooling operation to cool the storage chamber 12 by operating the compressor 27 (cooling device 20) and the internal fan 30. During the cooling operation, air in the storage chamber 12 drawn in through the intake port 38A of the casing 38 becomes cold air through heat exchange while passing through the cooler 25, and this cold air is blown out into the storage chamber 12 from the outlet port 32A. The air circulates in this manner, thereby cooling the storage chamber 12.

[0024] During normal cooling operation when the door 13 is not opened or closed, when the temperature inside the storage compartment 12 detected by the internal temperature sensor 36 drops to a lower limit internal temperature setting (for example, a temperature 3°C lower than the internal temperature setting), the control unit 17 stops the operation of the compressor 27 and the internal fan 30. On the other hand, when the temperature inside the storage compartment 12 rises to an upper limit internal temperature setting (for example, a temperature 3°C higher than the internal temperature setting), the control unit 17 operates the compressor 27 and the internal fan 30. This keeps the temperature inside the storage compartment 12 within a range from the lower limit internal temperature setting to the upper limit internal temperature setting.

[0025] The speed of the internal fan 30 during such normal cooling operation is preferably high to maximize the amount of air circulated and improve cooling efficiency. Furthermore, the operation of the internal fan 30 while the compressor 27 is stopped may be an intermittent operation in which the internal fan 30 is turned on and off repeatedly at a predetermined cycle.

[0026] Furthermore, the control unit 17 performs a defrosting operation at predetermined cooling operation times, etc. With the compressor 27 and the internal fan 30 stopped, the control unit 17 applies power to the defrosting heater 37 to heat the cooler 25, thereby melting and defrosting the frost adhering to the cooler 25. The defrost water generated by the melting is received on the bottom surface of the casing 38, and then flows down the drain hose 39 to be drained outside the cooler. The control unit 17 ends the defrosting operation when the temperature detected by the cooler temperature sensor 35 reaches the defrost completion temperature.

[0027] Furthermore, when the door 13 is opened or closed during the normal cooling operation described above, the control unit 17 continues to control the on / off state of the compressor 27 based on the above-described internal set lower limit temperature and internal set upper limit temperature, while for the internal fan 30, it executes the door opening / closing process shown in Fig. 3. The door opening / closing process for the internal fan 30 will be described below with reference to the flowchart in Fig. 3.

[0028] When the door sensor 14 detects that the door 13 has been opened while the control unit 17 is performing control based on the internal temperature setting lower limit and internal temperature setting upper limit during the normal cooling operation described above, the control unit 17 interrupts and starts door opening / closing processing to control the internal fan 30 as needed (S10). If the internal fan 30 is operating when the door 13 is opened (YES in S15), the control unit 17 stops the internal fan 30 (S20). On the other hand, if the internal fan 30 is stopped when the door 13 is opened, the control unit 17 keeps the internal fan 30 stopped (NO in S15). By stopping the internal fan 30 when the door 13 is opened in this way, the warm air that flows in from outside the compartment when the door 13 is opened is not actively mixed with the cold air inside the compartment, thereby suppressing a rise in the internal temperature.

[0029] When the door sensor 14 detects that the opened door 13 has been closed (YES in S25), the control unit 17 determines whether the open time of the door 13 (the time from when the door is opened to when it is closed) is equal to or longer than a preset threshold time (S30, an example of a first determination). If the result of the first determination is that the time is equal to or longer than the threshold time (YES in S30), the control unit 17 restarts the internal fan 30 at a low speed (S35). On the other hand, if the time is shorter than the threshold time (NO in S30), the door opening / closing process ends (returning to normal cooling operation).

[0030] Here, the case where the door 13 has been open for a long time equal to or longer than the threshold time (YES in S30) corresponds to a state where the temperature of the cooler 25 rises due to the door 13 being open for a long time, causing the frost adhering to the cooler 25 to melt and generate melted ice water. In this case, the temperature inside the storage chamber 12 reaches the upper limit temperature set inside the cabinet, and the compressor 27 is considered to be operating. The threshold time is the time required for melted ice water to be generated in the cooler 25 by opening the door 13 while the compressor 27 is operating, and is set appropriately depending on the specifications of the refrigerated storage cabinet 10, but may be, for example, three minutes.

[0031] In particular, since the refrigerated storage cabinet 10 according to this embodiment is a prefabricated refrigerated storage cabinet, a large amount of warm air flows in from outside the cabinet when the door 13 is opened. Also, no partition member is provided between the door 13 and the indoor unit 15. For this reason, even if the internal fan 30 is stopped (NO in S20 and S15) as described above and an excessive temperature rise is avoided, if the door 13 is left open for a long time, the temperature of the cooler 25 will reach the melting temperature of the frost (specifically, 0°C).

[0032] If the internal fan 30 is restarted at high speed while melted ice water has been generated in the cooler 25 in this manner, the melted ice water may be sucked into the internal fan 30, pass through the outlet 32A of the fan cover 32, and be scattered into the storage room 12. In particular, since the refrigerated storage cabinet 10 according to this embodiment is a prefabricated refrigerated storage cabinet, the wind power (suction force) of the internal fan 30 is large, making such a situation likely to occur.

[0033] Therefore, in this door opening / closing process, the internal fan 30 is restarted at a low speed (S35), thereby restarting the internal fan 30 with a low wind force (suction force). At this time, as described above, the temperature inside the storage compartment 12 reaches the upper limit temperature setting and the compressor 27 is operating. Therefore, restarting the internal fan 30 reduces the internal temperature. Furthermore, by restarting the internal fan 30 at a low speed, melted ice water is prevented from passing through the outlet 32A of the fan cover 32. In other words, the low speed of the internal fan 30 is set to a value lower than the maximum motor output of the main body 31 and to a speed that generates a wind force sufficient to prevent melted ice water adhering to the surface of the cooler 25 from passing through the outlet 32A. As a result, the melted ice water from the cooler 25, generated by opening and closing the door 13, from splashing into the storage compartment 12 is prevented. Furthermore, compared to using a duct or other device to prevent melted ice water from splashing, no additional components are required, resulting in lower costs.

[0034] After restarting the internal fan 30 at low speed, the control unit 17 determines whether the temperature detected by the cooler temperature sensor 35 (the temperature of the cooler 25) has fallen below a preset threshold temperature (e.g., 0°C, a second threshold temperature) (S45, an example of a second determination). If the result of the second determination is that the temperature detected by the cooler temperature sensor 35 is below the threshold temperature (YES in S45), the internal fan 30 is set to high speed (S50) and the door opening / closing process is terminated (returning to normal cooling operation). On the other hand, while the temperature detected by the cooler temperature sensor 35 is equal to or higher than the threshold, the internal fan 30 continues to operate at low speed (NO in S45).

[0035] Here, when the temperature detected by the cooler temperature sensor 35 falls below the threshold temperature (YES in S45), this corresponds to a state in which the temperature of the cooler 25 drops below the threshold temperature by continuing the cooling operation with the interior fan 30 restarted at low speed. In this case, the melted ice water freezes and does not scatter. Therefore, the control unit 17 switches the interior fan 30 to high speed (S50) and ends the door opening / closing process (returning to normal cooling operation). On the other hand, while the temperature detected by the cooler temperature sensor 35 is above the threshold (NO in S45), the melted ice water may not have frozen, so the interior fan 30 continues to operate at low speed (S55). In this way, by determining whether to continue operating the interior fan 30 at low speed based on the result of the second determination (S45), a situation in which the speed is switched to high speed even when the melted ice water may scatter can be avoided. As a result, the scattering of melted ice water can be reliably suppressed.

[0036] As described above, the cooler temperature sensor 35 according to this embodiment is disposed at a position separated from the surface of the cooler 25 where meltwater is likely to be generated, and there is a concern that a temperature difference may occur between the temperature detected by the cooler temperature sensor 35 and the surface temperature of the cooler 25 where meltwater is likely to be generated. Therefore, the control unit 17 counts the elapse of a predetermined time (S40) after restarting the internal fan 30 at low speed and before making the second determination (between S35 and S45).

[0037] In this way, the internal fan 30 can be restarted at low speed for a predetermined time before the second determination is made, thereby mitigating the temperature difference between the temperature detected by the cooler temperature sensor 35 and the surface temperature of the cooler 25, where melted ice water is likely to form. As a result, the accuracy of the second determination can be improved, and scattering of melted ice water can be more reliably suppressed.

[0038] <Embodiment 2> The process of the internal fan 30 when the door is opened or closed according to the second embodiment will be described with reference to Fig. 4. The second embodiment differs from the first embodiment mainly in the condition for the first determination. In the second embodiment, the same configuration and effects as those of the first embodiment will not be described again.

[0039] The control unit 17 performs steps S10 to S25, as in the first embodiment. When the door sensor 14 detects that the opened door 13 has been closed in step S25 (YES in S25), the control unit 17 determines whether the temperature detected by the cooler temperature sensor 35 (the temperature of the cooler 25) has risen to or above a preset threshold temperature (first threshold temperature) (S130, another example of a first determination). If the result of the first determination is that the temperature detected by the cooler temperature sensor 35 is equal to or above the threshold temperature (YES in S130), the control unit 17 restarts the internal fan 30 at a low speed (S35). On the other hand, if the temperature is below the threshold temperature (NO in S130), the door opening / closing process ends (returns to normal cooling operation).

[0040] Here, the case where the temperature detected by the cooler temperature sensor 35 is equal to or higher than the threshold temperature (YES in S130) corresponds to a state in which the temperature of the cooler 25 rises due to the door 13 being open for a long time, melting the frost and generating melted ice water. In this case, the temperature inside the storage compartment 12 reaches the upper limit temperature setting inside the storage compartment, and the compressor 27 is assumed to be operating. The threshold temperature is set to a temperature at which melted ice water is generated in the cooler 25 when the door 13 is open while the compressor 27 is operating, and is, for example, 0°C. However, the cooler temperature sensor 35 according to this embodiment is disposed at a position away from the surface of the cooler 25 where melted ice water is likely to be generated, and there is a concern that a temperature difference may occur between the temperature detected by the cooler temperature sensor 35 and the surface temperature of the cooler 25 where melted ice water is likely to be generated. For this reason, the threshold temperature is not limited to 0°C and may be set to a value lower than 0°C in consideration of this temperature difference.

[0041] After restarting the internal fan 30 at low speed, the control unit 17 performs a second determination (S45) similar to the door opening / closing process according to the first embodiment. If the result of the second determination is that the temperature detected by the cooler temperature sensor 35 is below the threshold temperature (YES in S45), the internal fan 30 is set to high speed (S50) and the door opening / closing process ends (returning to normal cooling operation). On the other hand, while the temperature detected by the cooler temperature sensor 35 is equal to or higher than the threshold, the internal fan 30 continues to operate at low speed (NO in S45). Note that the threshold temperature (first threshold temperature) in the first determination (S130) and the threshold temperature (second threshold temperature) in the second determination (S45) are both the same temperature, 0°C, in this embodiment; however, they may be different, for example, the former being 0°C and the latter being -1°C.

[0042] Furthermore, the control unit 17 may additionally execute a step (S40 in FIG. 3) of counting the passage of a predetermined time period after restarting the internal fan 30 at low speed and before making the second determination (between S35 and S45), as in the first embodiment.

[0043] <Other embodiments> The present technology is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope of the present technology.

[0044] (1) The cooler temperature sensor 35 is used to determine whether the defrost completion temperature has been reached during defrosting operation, and is also used as a so-called defrost thermistor. However, it may be provided as a separate component. For example, the cooler temperature sensor 35 may be provided in the vicinity of the surface of the cooler 25 where melted ice is likely to be generated, separate from the defrost thermistor. [Explanation of symbols]

[0045] 10: Cooling storage, 11: Storage body, 11S: Front opening (opening), 12: Storage room, 13: Door, 14: Door sensor, 17: Control unit, 20: Cooling device, 25: Cooler, 27: Compressor, 30: In-storage fan (circulation fan), 35: Cooler temperature sensor

Claims

1. a storage body having an opening and a storage chamber through which stored items are put in and taken out; a door for opening and closing the opening; a cooling device for cooling the storage chamber; a circulation fan having a variable rotation speed that circulates air in the storage chamber so as to return the air that has been sucked in from the storage chamber and cooled by a cooler that constitutes the cooling device to the storage chamber; and a door sensor that detects whether the door is open or closed; a cooler temperature sensor for detecting the temperature of the cooler; a control unit, The control unit, in a cooling operation for cooling the storage chamber, When the door sensor detects that the door has been opened, the circulation fan stops if it is operating, and continues to be stopped if it is stopped; When the door sensor detects that the opened door has been closed, a first determination is made; the first determination is whether or not an opening time from when the door is opened to when it is closed is equal to or longer than a threshold time, or whether or not a temperature detected by the cooler temperature sensor is equal to or longer than a first threshold temperature; The control unit of the refrigerated storage facility restarts the circulation fan, which is currently stopped, at a low speed within its variable range if the result of the first judgment is that the open time is equal to or greater than the threshold time, or if the detected temperature is equal to or greater than the first threshold temperature.

2. the control unit performs a second determination after restarting the circulation fan at the low speed, the second determination is whether or not the detected temperature of the cooler temperature sensor is less than a second threshold temperature; The cooling storage facility described in claim 1, wherein the control unit keeps the speed of the circulation fan at the low speed when the result of the second judgment is that the detected temperature is equal to or higher than the second threshold temperature, and increases the speed of the circulation fan to a high speed greater than the low speed when the detected temperature is lower than the second threshold temperature.

3. The refrigerated storage facility according to claim 2 , wherein the control unit makes the second determination after counting the passage of a predetermined time after restarting the circulation fan at the low speed.

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