JP2016223688A - Control method of freezing/refrigerating showcase - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method of a freezing/refrigerating showcase capable of defrosting evaporators without affecting contents such as frozen food, fresh food and the like.SOLUTION: In a control method of a freezing/refrigerating showcase 1 including evaporators 8F, 8R cooling ambient air by evaporating a refrigerant 16 flowing therein and cooling the inside of case 5 by using a refrigeration cycle C, the plurality of evaporators 8F, 8R are disposed in a manner that the refrigerant 16 flows in parallel, and the showcase is operated in an operation mode β that when at least one evaporator 8R is operated in a defrosting operation pattern, at least the other one evaporator 8F is operated in a cooling operation pattern.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for controlling a frozen / refrigerated showcase used for displaying frozen foods, fresh foods, and the like in supermarkets, convenience stores, and the like.

  In supermarkets and convenience stores, frozen and refrigerated showcases are arranged to display frozen foods and fresh foods while frozen or refrigerated. This refrigerated / refrigerated showcase includes a case main body constituted by an outer box and an inner box, and an evaporator and a blower installed in a ventilation path formed between the outer box and the inner box. Yes. When the refrigerant flowing into the evaporator evaporates, the evaporator is cooled by taking the heat of the air around the evaporator, and the cool air formed by the evaporator is cooled by the blower by the case body. Frozen foods and fresh foods that are sent to the storage room and displayed in the storage room are frozen or refrigerated.

  In such a refrigeration / refrigeration showcase, by continuing the cooling operation of the evaporator, frosting occurs in the evaporator, and there is a problem that the cooling capacity of the evaporator decreases. A freezer / refrigerated showcase as shown in Patent Document 1 has been developed. In this refrigeration / refrigeration showcase, the cooler (evaporator) is stopped at appropriate time intervals and heated by a heater to defrost the cooler.

No. 7-12861 (Page 2, Fig. 1)

  However, in the refrigeration / refrigeration showcase of Patent Document 1, the cooling operation of the cooler is stopped at the time of defrosting the cooler, so that the internal temperature rises and the internal temperature is If it is too high, the contents such as frozen food and fresh food may be affected.

  The present invention has been made paying attention to such problems, and provides a control method of a frozen / refrigerated showcase capable of defrosting an evaporator without affecting contents such as frozen food and fresh food. For the purpose.

In order to solve the above problems, the control method of the freezing and refrigeration showcase of the present invention,
A control method of a refrigeration / refrigeration showcase that includes an evaporator that cools ambient air by evaporating refrigerant flowing into the interior and cools the interior using a refrigeration cycle,
A plurality of the evaporators are installed so that the refrigerant flows in parallel,
When at least one evaporator is in a defrosting operation pattern, the operation is performed in an operation mode in which at least one other evaporator is in a cooling operation pattern.
According to this feature, in an operation mode in which an arbitrary evaporator has a defrosting operation pattern and another evaporator has a cooling operation pattern, when the arbitrary evaporator has a defrosting operation pattern, Since the vessel has a cooling operation pattern, the cooling capacity of the showcase is maintained, and an increase in the internal temperature can be prevented.

The refrigeration / refrigeration showcase includes an evaporation pressure adjusting device that adjusts the evaporation pressure of the refrigerant in the evaporator, and the evaporation pressure adjusting device is configured so that the evaporation pressure of the refrigerant is a predetermined value during the cooling operation pattern. The evaporator is switched to the defrosting operation pattern by adjusting so as to be higher than the evaporation pressure.
According to this feature, by switching the evaporator to the defrosting operation pattern by the evaporation pressure adjusting device, the refrigerant temperature in the evaporator becomes higher than the refrigerant temperature in the cooling operation pattern during the defrosting operation pattern. , Can be defrosted efficiently.

The plurality of evaporators includes two evaporators,
A first operation mode in which one evaporator and the other evaporator are in the cooling operation pattern;
A second operation mode in which the one evaporator is the cooling operation pattern and the other evaporator is the defrosting operation pattern;
The third evaporator is selected and operated from the third operation mode in which the one evaporator is the defrosting operation pattern and the other evaporator is the cooling operation pattern.
According to this feature, in the first operation mode in which one evaporator and the other evaporator are in the cooling operation pattern, the inside of the refrigerator can be efficiently cooled, and one of the evaporators is excluded. In the second or third operation mode, which is a frost operation pattern, the evaporator on the different side has a cooling operation pattern, so that an increase in the internal temperature can be prevented.

After performing the step of operating in either the second driving mode or the third driving mode, the step of operating in the first driving mode is performed.
According to this feature, since the operation steps of the second and third driving modes are not continued by performing the operating steps of the first driving mode after the operating steps of the second or third driving mode, the warehouse A state in which the internal temperature is higher than that in the first operating mode can be shortened.

The plurality of evaporators includes two evaporators,
An operation mode in which one of the evaporators is the cooling operation pattern and the other evaporator is the defrosting operation pattern;
An operation mode in which the one evaporator is the defrosting operation pattern and the other evaporator is the cooling operation pattern is alternately performed.
According to this feature, when one of the evaporators defrosts, the evaporator on the different side has a cooling operation pattern, so the cooling capacity of the showcase does not change in any operation mode, The inside temperature can always be made uniform.

1 is a side sectional view showing a freezing / refrigerating showcase in Embodiment 1. FIG. It is a block diagram which shows the structure of the piping system of a refrigerating cycle. It is a block diagram which shows the structure of an evaporator. It is a partially exploded perspective view which shows the structure of an evaporator. It is a block diagram which shows the evaporator and switching circuit at the time of a 1st driving | running aspect. It is a block diagram which shows the evaporator and switching circuit at the time of a 2nd driving | running aspect. (A) is a graph which shows the internal temperature in Example 1, and the surface temperature of each evaporator, (b) is a graph which shows the operation | movement aspect of each evaporator. (A) is an enlarged view of the enclosure part A in FIG. 7, (b) is a graph which shows the operation | movement aspect of each evaporator in (a). It is a table | surface figure which shows the experimental result at the time of actually operating the freezing and refrigeration showcase in Example 1. FIG. It is a sectional side view which shows the modification of a freezing / refrigeration showcase. It is a table | surface figure which shows the experimental result at the time of actually operating the freezing and refrigeration showcase of FIG. (A) is a graph which shows the internal temperature in Example 2, and the surface temperature of each evaporator, (b) is a graph which shows the operation | movement aspect of each evaporator. (A) is a table | surface which shows the experimental result at the time of actually operating the freezing / refrigeration showcase in Example 2, (b) provides a damper apparatus in the freezing / refrigeration showcase in Example 2, It is a table | surface figure which shows the experimental result at the time of actually operating. 6 is a block diagram showing a switching circuit of a freezing / refrigerating showcase in Embodiment 3. FIG.

  EMBODIMENT OF THE INVENTION The form for implementing the freezing / refrigeration showcase which concerns on this invention is demonstrated below based on an Example.

  The refrigeration / refrigeration showcase according to the first embodiment will be described with reference to FIGS. Hereinafter, the left side of the screen in FIG. 1 will be described as the front side (front side) of the freezing / refrigeration showcase.

  As shown in FIG. 1, the refrigerated / refrigerated showcase 1 is installed in a store that mainly handles foods such as stores, supermarkets, and convenience stores, and the product is kept cold or frozen while keeping the product at a low temperature. A plurality of shelves 6, 6,... For displaying products are installed in the cold storage room 5, which is installed for display and surrounded by an inner box 3 that opens at the front side. A product (not shown) can be displayed on the bottom 3b provided at the lower part of 3 so that a large number of products can be placed.

  The refrigerated / refrigerated showcase 1 includes a substantially U-shaped outer box 2 having a front surface (left side in the figure) opened and a substantially U-shaped inner box 3 having a front surface opened to the inside. The interior space is a cold storage room 5 (inside the cabinet). The rear ends of brackets 28, 28,... Extending in the front-rear direction are attached to the back surface portion 3a of the inner box 3, and the shelf boards 6, 6,. . A product (not shown) is displayed on the upper surfaces of the shelf boards 6, 6... And the bottom 3 b of the inner box 3.

  A ventilation path 7 is formed between the outer box 2 and the inner box 3, and evaporators 8F and 8R and a blower 9 are installed on the vertical part and the horizontal bottom part of the ventilation path 7, respectively. As will be described later, the evaporators 8F and 8R can cool the surrounding air. Further, heat insulating materials 29 and 29 are provided on the front sides of the evaporators 8F and 8R, and heat exchange between the evaporators 8F and 8R and heat exchange between the evaporator 8 and the cold insulation chamber 5 are performed. It is suppressed. A cold air outlet 10 that communicates with the air passage 7 is formed downward at the front end of the upper portion of the case body, and a cold air inlet 11 that opens upward is formed at the upper end of the lower front end of the case body. .

  When the blower 9 is operated, the cold air cooled by the evaporators 8F and 8R flows upward in the ventilation path 7 as indicated by the arrow, and blows out from the cold air outlet 10 toward the lower inlet 11. Is done. As a result, a cold air curtain 12 is formed on the open surface of the front surface of the case body, and a part of the cold air flows into the cold insulation chamber 5 so that the displayed product is kept cold. These evaporators 8F and 8R are set so that the temperature of the air blown from the cold air outlet 10 (outlet temperature) is substantially 0 ° C., and even if only one side evaporator is operated. A capacity capable of cooling the outlet temperature to 0 ° C. is provided. The evaporator may have a capacity that cools the outlet temperature to 0 ° C. when both the evaporators 8F and 8R are operated.

  Next, the evaporators 8F and 8R in the freezer / refrigerated showcase 1 will be described. As shown in FIG. 1, the evaporator 8 </ b> F is disposed on the front side of the ventilation path 7, and the evaporator 8 </ b> R is disposed on the rear side of the ventilation path 7. In addition, although the present Example demonstrated the case where evaporator 8F, 8R was arrange | positioned forward and backward, two evaporators may be arrange | positioned up and down, and may be arrange | positioned right and left. Furthermore, since the structures of the evaporator 8F and the evaporator 8R are substantially the same, only the evaporator 8F on the front side will be described, and the description of the evaporator 8R will be omitted.

  As shown in FIGS. 2 to 4, the evaporator 8F includes a heat transfer tube 15 through which the refrigerant 16 flows, and the heat transfer tube 15 meanders through the plurality of fins 30, 30,. This increases the contact area between the heat transfer tube 15 and the surrounding air, efficiently blows air from the blower 9, and improves the cooling efficiency. Specifically, as shown in FIG. 4, the heat transfer tube 15 includes a plurality of straight tube portions 15a, 15a,... Penetrating through the plurality of fins 30, 30,. .. (For convenience of explanation, only one U bend portion 15b is shown in FIG. 4), and assembly is easy. Since the heat transfer tube 15 is structurally located at the end portions of the U bend portions 15b, 15b,..., It is difficult for the air blow from the blower 9 to hit the U bend portions 15b, 15b,. The bend portions 15b, 15b,... Are more easily frosted than the straight pipe portions 15a, 15a,.

  As shown in FIG. 2, the evaporator 8F and the evaporator 8R are part of the piping system C of the refrigeration cycle, and are arranged in parallel with the circuits in the piping system C of the refrigeration cycle. . Specifically, at the upstream end of each of the evaporator 8F and the evaporator 8R, an expansion valve 17 that reduces the liquefied refrigerant 16 to a vaporized state by reducing the refrigerant 16 to a predetermined evaporation pressure (temperature), 17 is provided, and a liquid receiver 18 for storing the refrigerant 16 is connected to the expansion valves 17 and 17 via supply pipes 19 and 19 respectively connected thereto. Further, switching circuits 20 and 20 (evaporation pressure adjusting devices) are connected to the downstream ends of the evaporator 8F and the evaporator 8R, respectively, and the evaporator 8F is connected to the downstream side of the switching circuits 20 and 20. And a compressor 21 which sucks the vaporized refrigerant 16 evaporated in the evaporator 8R and compresses the refrigerant 16 and sends it to the liquid receiver 18 side. The compressor 21 is connected via a condenser 22. Connected to the liquid receiver 18. The condenser 22 releases the heat of the refrigerant 16 in the high-pressure vaporized state compressed by the compressor 21 to the outside to make the refrigerant 16 liquefied.

  In FIG. 2, the refrigerant 16 in the liquid (liquefied) state is indicated by a solid line, and the refrigerant (vaporized) state is indicated by a broken line. The temperature of the liquefied refrigerant 16 in the liquid receiver 18 is about 35 ° C. to 40 ° C. in summer and about 20 ° C. in winter.

  As shown in FIGS. 2 and 5, the switching circuit 20 on the evaporator 8F side is in parallel with the first pipe 23 (the other distribution path) communicating with the heat transfer pipe 15 of the evaporator 8F and the first pipe 23. A second pipe 24 (one flow path) which is a bypass pipe provided, a three-way switching valve 25 (switching means) provided at an upstream intersection of the first pipe 23 and the second pipe 24, and a second pipe 24 The evaporation pressure adjusting valve 26 (EPR) and a check valve 27 provided on the downstream side of the evaporation pressure adjusting valve 26 are provided. Since the switching circuit 20 on the evaporator 8R side has the same configuration as the switching circuit 20 on the evaporator 8F side, only the switching circuit 20 on the evaporator 8F side will be described, and the switching circuit 20 on the evaporator 8R side will be described. Is omitted.

  The three-way switching valve 25 closes the second pipe 24 and connects the heat transfer pipe 15 and the first pipe 23 (see FIG. 5), closes the first pipe 23, and connects the heat transfer pipe 15 and the second pipe 24. Can be switched to the communication mode (see the three-way switching valve 25 ′ on the lower side of the screen in FIG. 6). The three-way switching valve 25 is controlled to be switched at predetermined time intervals by a control unit (not shown). By switching the three-way switching valve 25, the evaporator 8F and the evaporator 8R can be switched between a cooling operation pattern for cooling the surrounding air and a defrosting operation pattern for removing frost adhering to the heat transfer tube 15, respectively. It has become. The operation of the cooling operation pattern and the defrosting operation pattern of the evaporator 8F and the evaporator 8R will be described in detail later.

  The evaporation pressure adjusting valve 26 is a valve element that opens the flow path in the second pipe 24 at a set pressure or higher and closes the flow path in the second pipe 24 at a pressure lower than the set pressure. The pressure of the refrigerant 16 flowing into the vessel 8F is adjusted. This set pressure is set to a pressure higher than a predetermined evaporation pressure of the refrigerant 16 in the evaporator 8F when the evaporator 8F is in the cooling operation pattern.

  The check valve 27 prevents the downstream side refrigerant 16 from flowing back to the evaporation pressure adjusting valve 26 side when the three-way switching valve 25 is switched to the second pipe 24 side.

  As shown in FIG. 7B, the refrigeration / refrigeration showcase 1 configured as described above includes a first operation mode α in which both the evaporator 8F and the evaporator 8R are in a cooling operation pattern, and an evaporator. 8F is the cooling operation pattern, the evaporator 8R is the second defrosting operation pattern β, the evaporator 8F is the defrosting operation pattern, and the third operation is the evaporator 8R is the cooling operation pattern. And an aspect γ.

  Next, the operation in the first operation mode α in which both the evaporator 8F and the evaporator 8R are in the cooling operation pattern will be described. As shown in FIGS. 2 and 5, in the first operation mode α, the three-way switching valves 25, 25 ′ close the second pipes 24, 24, and the heat transfer pipes 15, 15 and the first pipe 23, 23 is communicated. When the compressor 21 is operated, the liquefied refrigerant 16 stored in the liquid receiver 18 is sent to the evaporator 8F and the evaporator 8R through the supply pipes 19 and 19 and the expansion valves 17 and 17. When the refrigerant 16 in the liquefied state passes through the expansion valves 17, 17, the refrigerant is decompressed by the expansion valves 17, 17 to a predetermined evaporation pressure, and is in a vaporized state. The vaporized refrigerant 16 that has flowed into the heat transfer tubes 15 and 15 of the evaporator 8F and the evaporator 8R removes heat from the air in the ventilation path 7, whereby the air in the ventilation path 7 is cooled.

  The vaporized refrigerant 16 that has passed through the heat transfer tubes 15 and 15 of the evaporator 8F and the evaporator 8R flows into the first pipes 23 and 23 that communicate with the heat transfer tubes 15 and 15, and passes through the compressor 21 and the condenser 22. To the receiver 18. By repeating this operation, the cooling operation pattern of the evaporator 8F and the evaporator 8R is continuously continued.

  As shown in FIG. 7 (a), in the first operation mode α, both the evaporator 8F and the evaporator 8R are in the cooling operation pattern, so the cooling capacity of the refrigeration / refrigeration showcase 1 is high. It can cool the inside efficiently. Each surface temperature of the heat transfer tube 15 of the evaporator 8F and the heat transfer tube 15 of the evaporator 8R in this cooling operation pattern is around −10 ° C., and as shown in FIG. The internal temperature is kept at approximately + 2 ° C. In addition, the inside temperature here refers to the temperature in the vicinity of the shelf boards 6, 6,.

  Next, the operation of the second operation mode β in which the evaporator 8F is the cooling operation pattern and the evaporator 8R is the defrosting operation pattern will be described. Since the cooling operation pattern of the evaporator 8F has the same configuration as the operation in the first operation mode α described above, the evaporator 8R only explains the defrosting operation pattern, and the cooling operation pattern on the evaporator 8F side. The description of is omitted.

  As shown in FIGS. 2 and 6, in the second operation mode β, the first pipe 23 is closed by the three-way switching valve 25 ′ connected to the evaporator 8 </ b> R, and the heat transfer pipe 15 and the second pipe 24 are closed. Communicate with. The vaporized refrigerant 16 that has passed through the heat transfer tube 15 of the evaporator 8 </ b> R flows into the second pipe 24 that communicates with the heat transfer tube 15.

  At this time, the refrigerant 16 in the heat transfer pipe 15 and the second pipe 24 has a pressure (predetermined evaporation pressure) lower than the set pressure of the evaporation pressure adjustment valve 26 as described above. 26 is the state which obstruct | occluded the 2nd piping 24. FIG. The refrigerant 16 flowing into the second pipe 24 is blocked by the closed evaporation pressure adjusting valve 26, so that the expansion valve 17 provided upstream of the evaporator 8F is connected to the closed evaporation pressure adjusting valve 26. As the pressure in the section increases and increases above the set pressure, the evaporation pressure regulating valve 26 opens the second pipe 24. In other words, the evaporating pressure adjusting valve 26 controls the evaporating pressure of the refrigerant 16 flowing into the section from the expansion valve 17 to the evaporating pressure adjusting valve 26 so that it does not drop below the set pressure.

  According to this, the refrigerant 16 that has flowed into the heat transfer tube 15 of the evaporator 8R is compressed by the evaporation pressure adjusting valve 26, and has a higher evaporation pressure than in the cooling operation pattern, and its temperature is 0 ° C. or higher (+ 5 ° C.). To rise. Therefore, when the evaporator 8R is in the defrosting operation pattern state (the state where the heat transfer pipe 15 and the second pipe 24 are communicated by switching the three-way switching valve 25 ′), the refrigerant 16 whose temperature has risen to 0 ° C. or more. Thus, the frost attached to the outer surface of the heat transfer tube 15 can be melted and removed. In this way, since the defrosting is performed from the inside of the heat transfer tube 15 using the temperature of the refrigerant 16, the bent heat transfer tube 15 is particularly easily frosted and is not easily defrosted at the U bend portions 15b, 15b,. Even if it exists, while being able to defrost to every corner, defrosting efficiency is high and it can defrost in a short time. Furthermore, since it is not necessary to use an external heat source such as a heater in the defrosting of the evaporator 8R, it is easy to adjust the internal temperature.

  Further, when the pressure in the section from the expansion valve 17 to the evaporation pressure adjusting valve 26 increases to a set pressure higher than a low pressure (predetermined vapor pressure), the evaporation pressure adjusting valve 26 is opened. With the pressure adjustment valve 26, the pressure in the section from the expansion valve 17 to the evaporation pressure adjustment valve 26 becomes the set pressure, the evaporation temperature does not become 5 ° C. or higher, and a rapid rise in the internal temperature can be prevented, and evaporation can be prevented. The defrosting operation is reliably performed without lowering the temperature. In addition, the refrigerant 16 that has passed through the evaporation pressure regulating valve 26 that has been opened due to the pressure increasing above the set pressure flows into the compressor 21 via the check valve 27.

  As shown in FIGS. 7, 8, and 9, in the second operation mode β, the surface temperature of the heat transfer tube 15 of the evaporator 8 </ b> R is around −1 ° C. from the start of the defrosting operation pattern. Rises rapidly. This is because the three-way switching valve 25 is switched and the refrigerant 16 in the evaporator 8R is compressed by the evaporation pressure adjusting valve 26. Further, the surface temperature of the heat transfer tube 15 of the evaporator 8R gradually rises from around -1 ° C to around 0 ° C. This is because the surface temperature is difficult to increase because there is unmelted frost attached to the outer surface of the heat transfer tube 15. Further, the surface temperature of the heat transfer tube 15 of the evaporator 8R rises again to around + 5 ° C around 0 ° C. This is because the surface temperature is likely to rise again due to the complete or almost complete melting of the frost.

  Further, the surface temperature of the heat transfer tube 15 of the evaporator 8R is adjusted by the evaporation pressure adjusting valve 26 so that the evaporation pressure of the refrigerant 16 in the evaporator 8R becomes substantially constant. When the defrosting of the evaporator 8F is completed, the internal temperature in the cold insulation chamber 5 is about + 4 ° C. The surface temperature of the heat transfer tube 15 is measured by the U-bend portions 15b and 15b where heat exchange hardly occurs. Furthermore, since the operation of the third operation mode γ in which the evaporator 8F is the defrosting operation pattern and the evaporator 8R is the cooling operation pattern is substantially the same as the operation of the second operation mode β, Description of the operation of the third driving mode γ is omitted.

  Further, as shown in FIG. 9, in this embodiment, after the first operation mode α is performed for about 3 to 6 hours, the second operation mode β or the third operation mode γ (EPR operation) is performed. It takes about 30 to 40 minutes. In addition, when the first operation mode α and the second operation mode β or the third operation mode γ are switched, the cold air temperature (the outlet temperature) in the first operation mode α, The time zone during which the temperature of the cold air (the outlet temperature) in the operation mode β or the third operation mode γ is mixed and circulated through the inside of the cabinet is generated, as described above, The increase in the evaporation temperature from the first operation mode α in the second operation mode β and the third operation mode γ is small, and the increase in the internal temperature is only slightly increased from 2 ° C. to 4 ° C. and Since this temperature rise time is short, the temperature unevenness in the warehouse can be reduced, and even if the operation time of the second operation mode β or the third operation mode γ is increased, the effect on the displayed products is reduced. it can.

  Further, as shown in FIGS. 7B and 9, after the second operation mode β or the third operation mode γ is operated, the operation is performed in the first operation mode α. . According to this, since the operation of the second operation mode β or the third operation mode γ is not continuous, the state in which the internal temperature becomes higher than that in the first operation mode α can be shortened, and the internal temperature can be reduced. Change can be reduced.

  As described above, when any one of the evaporator 8F and the evaporator 8R has the defrosting operation pattern, the other one of the evaporator 8F and the evaporator 8R has the cooling operation pattern. The cooling capacity is maintained, and an excessive rise in the internal temperature can be prevented. That is, it is possible to prevent the internal temperature from rising to a temperature that affects the products displayed in the cold room 5.

  Further, switching circuits 20 and 20 are provided on the downstream side of the evaporator 8F and the evaporator 8R, and the evaporation pressure adjusting valves 26 and 26 of the switching circuits 20 and 20 are predetermined via the expansion valves 17 and 17, respectively. Therefore, the evaporating pressures of the refrigerants 16 and 16 in the evaporator 8F and the evaporator 8R can be stably and reliably adjusted. Further, since the members for adjusting the evaporation pressure of the refrigerants 16 and 16 in the evaporator 8F and the evaporator 8R are not concentrated upstream of the evaporator 8F and the evaporator 8R, the evaporator in the piping system C of the refrigeration cycle. The structure upstream of 8F and the evaporator 8R can be simplified.

  Further, when the heat transfer pipe 15 and the first pipe 23 communicate with each other by the three-way switching valve 25 of the switching circuit 20, the refrigerant 16 flows into the heat transfer pipe 15 with the evaporation pressure of the refrigerant 16 being low, and the evaporator 8F or 8R is connected. Since the cooling operation pattern can be used and the switching circuit 20 is used, for example, there is no need to use an expensive adjustment valve or the like that automatically adjusts the opening, and switching using the evaporation pressure adjustment valve 26 having a simple structure is possible. The circuit 20 can easily control the cooling operation pattern and the defrosting operation pattern of the evaporator.

  Further, since the evaporator 8F and the evaporator 8R are connected in parallel in the piping system C of the refrigeration cycle, the evaporator 8F and the evaporator 8R can be easily controlled separately. Further, since the switching circuits 20 and 20 are provided for each of the evaporator 8F and the evaporator 8R, the evaporator 8F and the evaporator 8R can be controlled very easily and separately.

  In the above-described embodiment, the refrigeration / refrigeration showcase 1 has been described for displaying products in a refrigerated state. However, the decompression capacity of the expansion valves 17 and 17 and the set pressure of the evaporation pressure adjusting valves 26 and 26 are changed. By this, the inside temperature can be changed to a temperature zone such as freezing or refrigeration near normal temperature.

  Moreover, there are the following as modifications of the above embodiment. As shown in FIG. 10, on the heat insulating material 29 that partitions the evaporators 8F and 8R, a swinging member 31a that can swing so as to close the space above either the evaporator 8F or the evaporator 8R. A damper device 31 is provided. In the first operation mode α, the swing member 31a of the damper device 31 stands upright to open the space above the evaporator 8F and the evaporator 8R, and the second operation mode β or the third operation mode. In the case of the mode γ, the control is performed by a control means (not shown) so as to swing to the evaporator side in the defrosting operation pattern and cut off the communication between the evaporator and the inside of the refrigerator.

  According to this, as shown in FIG. 11, only the cold air passing through the evaporator in the cooling operation pattern is circulated in the cabinet, so that the heat exchange between the evaporator 8F and the evaporator 8R is performed. Occurrence is suppressed, and the air outlet temperature is maintained at about 0 ° C. in any of the operation modes of the first operation mode α, the second operation mode β, or the third operation mode γ. The internal temperature is stable at about 2 ° C. without temperature unevenness. In this way, if the damper device 31 is used, the internal temperature is stabilized at about 2 ° C. without temperature unevenness, so switching between the first operation mode α, the second operation mode β, or the third operation mode γ is possible. Can be done freely. In this modification, each operation mode is changed about every 1 hour. Compared to the first embodiment, the time during which the evaporator 8F and the evaporator 8R are in the cooling operation pattern is shortened, and the defrosting operation pattern. The time has been extended. According to this, while being able to end a cooling operation pattern in a state with little frost formation, a defrost operation pattern can be performed until there is no frost residue.

  As described above, when emphasizing the stability of the internal temperature, an aspect like this modified example is preferable, and when emphasizing the cost aspect, an aspect like Example 1 is preferable.

  Next, a freezing / refrigerating showcase according to Embodiment 2 will be described with reference to FIGS. The description of the same configuration as that shown in the above embodiment is omitted.

  As shown in FIG. 12, the refrigeration / refrigeration showcase of the present embodiment includes a second operation mode β ′ and a third operation mode γ ′, and the second operation mode β ′ and The third operation mode γ ′ is alternately performed. Thus, when one of the evaporators is in the defrosting operation pattern, the evaporator on the different side is in the cooling operation pattern, so that either the second operation mode β ′ or the third operation mode γ ′ Even in this operation mode, the freezing / refrigerating showcase does not change, and the inside temperature can always be made uniform.

  As shown in FIG. 13A, when the damper device 31 is not provided, both the outlet temperature and the internal temperature are about 4 ° C., and as shown in FIG. When the apparatus 31 is provided, both the outlet temperature and the internal temperature are about 2 ° C.

  As described above, when the second operation mode β ′ and the third operation mode γ ′ are alternately performed and the damper device 31 is provided, the temperature is the highest in the first and second embodiments and the modification examples described above. There is little unevenness and it is possible to efficiently stabilize the internal temperature at a low state.

  Next, a freezing / refrigerating showcase according to Embodiment 3 will be described with reference to FIG. The description of the same configuration as that shown in the above embodiment is omitted.

  As shown in FIG. 14, a switching circuit 200 is connected to the downstream side of the evaporator 8F and the evaporator 8R. The switching circuit 200 includes first pipes 23 and 23 and second pipes 24 and 24 communicating with the evaporator 8F and the evaporator 8R, and three-way switching is performed at the intersections of the first pipe 23 and the second pipe 24. Valves 25, 25 are provided. The second pipes 24, 24 are connected to each other to form a joining pipe 24a, and one joining pressure 24 and a check valve 27 are provided in the joining pipe 24a. According to this, the operation pattern of the evaporator 8F and the evaporator 8R can be switched by using only the operation of switching the three-way switching valves 25, 25, and also using the single evaporation pressure adjusting valve 26. Manufacturing costs can be reduced.

  In the above-described embodiment, the evaporator on one side has a cooling operation pattern and the evaporators are connected in parallel during the defrosting operation pattern of the evaporator. For this reason, in the defrosting operation pattern of the evaporator, the refrigerant 16 is defrosted in a higher pressure state than in the cooling operation pattern. However, the present invention is not limited to this. For example, the cooling operation pattern of the evaporator is stopped. Then, defrosting may be performed using a defrosting device such as a heater, or defrosting may be performed simply by stopping the cooling operation pattern of the evaporator. Even in this case, since the evaporator on one side has a cooling operation pattern, substantially the same effect as in the above embodiment can be obtained.

  In the above embodiment, the three-way switching valves 25 and 25 ′ are controlled to be switched every predetermined time. However, the present invention is not limited to this, and the evaporator 8F or the evaporator 8R is cooled from the defrosting operation pattern. When switching to the operation pattern, a control unit that detects the surface temperature of the heat transfer tube 15 (the surface temperature of the U-bend portion 15b) and switches the three-way switching valves 25 and 25 ′ based on the detection result is provided. The controller 8 may switch the evaporator 8F or the evaporator 8R from the defrosting operation pattern to the cooling operation pattern by switching the three-way switching valves 25 and 25 ′ when the surface temperature of 15 reaches 0 ° C. According to this, when the defrosting is completed, the defrosting operation pattern can be efficiently switched to the cooling operation pattern. Further, the controller controls the evaporator 8F or the evaporator 8R from the defrosting operation pattern to the cooling operation pattern after a predetermined time has elapsed (so-called delay control). ), And this can reliably prevent frost residue.

  Further, when the evaporator 8F or the evaporator 8R is switched from the cooling operation pattern to the defrosting operation pattern, when the surface temperature of the heat transfer tube 15 rises by a predetermined level or more than the appropriate temperature in the cooling operation pattern, the three-way switching valve 25 , 25 ′, the evaporator 8F or the evaporator 8R may be switched from the cooling operation pattern to the defrosting operation pattern. According to this, at the time when the cooling efficiency of the evaporator 8F or the evaporator 8R is lowered due to the frost adhering, the cooling operation pattern can be efficiently switched to the defrosting operation pattern.

  Further, the evaporation pressure adjusting valves 26 and 26 may be provided between the evaporators 8F and 8R and the expansion valves 17 and 17, respectively, and the evaporation pressure may be adjusted upstream of the evaporators 8F and 8R.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the above-described embodiment, the evaporator 8F and the evaporator 8R having the same configuration are used. For example, a plurality of evaporators having different capacities in the heat transfer tubes and different cooling capacities may be used.

  Further, although two evaporators 8F and 8R are used, when any evaporator has a defrosting operation pattern, if at least one other evaporator is a cooling operation pattern, three or more evaporations An oven may be used, and as the number of evaporators increases, the inside temperature can be finely adjusted. In addition, when goods are not displayed in the cool room 5 after closing, etc., you may make it stop all the evaporators (piping system C of a refrigerating cycle), and defrost at a stretch with a heater etc. .

  Moreover, in the said Example, although the switching means was demonstrated as the three-way switching valve 25,25 ', for example, the two-way switching valve is provided in each of the first pipe 23 and the second pipe 24 in the switching circuit 20, and each two-way switching valve. May be switched between the cooling operation pattern and the defrosting operation pattern of the evaporator by appropriately opening and closing.

1 Refrigeration / Refrigeration Showcase 5 Cold room (inside)
7 Ventilation path 8F, 8R Evaporator 9 Blower 15 Heat transfer tube 15b U bend part 16 Refrigerant 17 Expansion valve 20 Switching circuit (evaporation pressure adjusting device)
21 Compressor 23 1st piping (the other distribution route)
24 Second piping (one distribution channel)
25, 25 'three-way switching valve (switching means)
26 Evaporation pressure adjustment valve (pressure adjustment valve)
C Refrigeration cycle piping system α First operation mode β, β ′ Second operation mode γ, γ ′ Third operation mode

Claims (5)

A control method of a refrigeration / refrigeration showcase that includes an evaporator that cools ambient air by evaporating refrigerant flowing into the interior and cools the interior using a refrigeration cycle,
A plurality of the evaporators are installed so that the refrigerant flows in parallel,
A control method for a refrigeration / refrigeration showcase, characterized in that when at least one of the evaporators has a defrosting operation pattern, the operation can be performed in an operation mode in which at least one of the other evaporators has a cooling operation pattern.   The refrigeration / refrigeration showcase includes an evaporation pressure adjusting device that adjusts the evaporation pressure of the refrigerant in the evaporator, and the evaporation pressure adjusting device is configured so that the evaporation pressure of the refrigerant is a predetermined value during the cooling operation pattern. The method for controlling a refrigeration / refrigeration showcase according to claim 1, wherein the evaporator is switched to the defrosting operation pattern by adjusting the evaporation pressure to be higher than the evaporation pressure. The plurality of evaporators includes two evaporators,
A first operation mode in which one evaporator and the other evaporator are in the cooling operation pattern;
A second operation mode in which the one evaporator is the cooling operation pattern and the other evaporator is the defrosting operation pattern;
3. The third operation mode in which the one evaporator is the defrosting operation pattern and the other evaporator is the cooling operation pattern. The control method of the freezing / refrigeration showcase as described.   The refrigeration / acceleration according to claim 3, wherein after the step of operating in either the second operation mode or the third operation mode is performed, the step of operating in the first operation mode is performed. Control method of refrigerated showcase. The plurality of evaporators includes two evaporators,
An operation mode in which one of the evaporators is the cooling operation pattern and the other evaporator is the defrosting operation pattern;
The refrigeration / refrigeration according to claim 1 or 2, wherein the operation mode in which the one evaporator is the defrosting operation pattern and the other evaporator is the cooling operation pattern is alternately performed. Showcase control method.

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