JPH0722366U - Temperature zone switchable showcase - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent problems such as short cycle and high pressure rise that occur in high temperature zones in a showcase where switches are used to cool temperature zones with different temperature ranges. [Structure] A second solenoid valve 6 is provided between the evaporator 5 and the compressor 1 of the refrigerant circuit, and a suction pressure adjusting device 7 is provided by bypassing the second solenoid valve 6. Then, in cooperation with the temperature control device, only when the temperature zone is high, the second solenoid valve 6 is closed, the refrigerant is caused to flow into the suction pressure adjusting device 7 to be depressurized, and then returned to the compressor 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a low-temperature showcase, and more particularly to a showcase having a temperature control device having different refrigeration and freezing temperature ranges and capable of switching the inside of the refrigerator to different temperature zones.

[0002]

[Prior art]

 Generally, as shown in FIG. 3, a showcase displaying, selling and storing food in a supermarket or a convenience store stores a compressor 21 for compressing a refrigerant gas, a condenser 22 for converting a high pressure gas into a liquid, and a refrigerant. It comprises an electromagnetic valve 23 (SV0) for controlling the supply and stop of the refrigerant, an expansion valve 24 for squeezing the refrigerant liquid, and an evaporator 25 for evaporating the refrigerant liquid to cool the inside of the refrigerator. In addition, this showcase can control two temperature zones of 0 ° C to 5 ° C for refrigeration of fresh food such as vegetables and fruits and -15 ° C to -20 ° C for freezing of frozen foods. It has become.

The temperature control device 20 of the showcase having a structure for controlling the cooling temperature by switching between these two temperature zones has conventionally been performed by switching between two thermostats. That is, as shown in FIG. 4, a temperature control thermostat TSL for refrigeration is provided in series with an operation circuit for operating the solenoid valve 23 (SV0) for starting the circulation of the refrigerant in the refrigeration cycle, and a freezing / refrigeration changeover switch is also provided in series therewith. A contact for SW is provided, and a temperature control thermostat TSM for refrigeration is provided by bypassing the contact for the freezing / refrigeration selector switch SW.

According to this structure, when the freezing / refrigerating changeover switch SW is OFF, the freezing temperature adjusting thermostat TSL is always higher than the set temperature, so that it continues to be turned ON, and the temperature is set higher than the set temperature by setting the refrigerating temperature adjusting thermostat TSM. When the temperature rises, the compressor 21 and the solenoid valve 23 (SV0) are operated to cool it. When the temperature is lower than the set temperature, the cooling is stopped and the showcase is controlled for refrigeration. Further, when the freezing / refrigeration selector switch SW is ON and the temperature is equal to or higher than the setting of the temperature control thermostat TSL for freezing, the compressor 21 and the solenoid valve 23 (SV 0) are always operated to cool the showcase. Control for freezing.

[0005]

[Problems to be solved by the device]

 However, since the capacity of the refrigerator with multiple temperature zones described above is designed on the low temperature side, when used in a high temperature zone (when the set temperature is significantly higher than the evaporation temperature), In the thermostat-only control, the temperature-sensitive part of the thermostat TSM is near the cooler (evaporator 25) as in the above example, and the temperature of the temperature-sensitive part drops and rises quickly, and the inside of the refrigerator is not cooled sufficiently. If the refrigerator is stopped before, and it is driven immediately, and the start and stop of the refrigerator are repeated in a short period of time (so-called short cycle), the refrigerator is burdened and its life is shortened. was there.

[0006] Further, since the high-pressure refrigerant that has not reached the proper suction pressure returns to the compressor 21 with respect to the capacity of the refrigerator, the high-pressure pressure rises due to the compression of the compressor 21, and the pressure switch or the like operates. There is also a problem that the life of the refrigerator is adversely affected by the high pressure.

The present invention was devised in view of the above problems, and prevents a short cycle in which a refrigerator starts and stops repeatedly in a short period of time, and prevents an abnormal increase in high pressure. It is intended to provide a temperature zone switchable showcase.

[0008]

[Means for Solving the Problems]

 To achieve the above object, in the present invention, in a temperature zone switching type showcase having a plurality of temperature control devices having different temperature ranges and capable of arbitrarily switching the temperature ranges, the evaporator and the compressor of the refrigerant circuit are A solenoid valve is provided between them, and a suction pressure adjusting device is provided by bypassing this solenoid valve so that the refrigerant flows into the suction pressure adjusting device only when the temperature zone is high in cooperation with the temperature control device. It is characterized by switching to. Then, as the above-mentioned suction pressure adjusting device, a suction pressure adjusting valve or a capillary tube is used.

[0009]

[Work]

 Since the above configuration is adopted, the refrigerant is introduced into the suction pressure adjusting device in cooperation with the temperature control device only when the temperature zone is high, the pressure is reduced, and the refrigerant is returned to the compressor as an appropriate suction pressure of the refrigeration cycle. Therefore, it is possible to prevent a short cycle, a rise in high pressure, and the like, which have been problems in the past, and to extend the life of the refrigerator.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing a refrigerant circuit of a showcase of the present invention, and FIG. 2 is a schematic diagram of a temperature control device of the present invention.

In FIG. 1, reference numeral 1 is a compressor for compressing a gaseous refrigerant (usually Freon 12) to a high pressure, and 2 is a condenser for converting the high-pressure gaseous refrigerant into a high-pressure liquid, on the back or bottom of the showcase. It is provided so that it can exchange heat with air. The first solenoid valve (SV1) 3 has a function of supplying and stopping the refrigerant. An expansion valve 4 reduces the pressure by squeezing the refrigerant liquid. Reference numeral 5 is an evaporator for converting a liquid refrigerant into a low-pressure gas, which cools the inside of the showcase cabinet.

In the refrigerant circuit of the showcase of the present invention, the second solenoid valve 6 (SV2) is provided between the evaporator 5 and the compressor 1 described above, and the solenoid valve 6 (SV2) is bypassed for suction. A feature is that a pressure adjusting device (suction pressure adjusting valve) 7 is provided.

In FIG. 2, a temperature control device 10 for a showcase according to the present invention comprises a conventional refrigeration temperature control thermostat connected in series with an operation circuit for activating a first solenoid valve SV1 for starting circulation of a refrigerant in a conventional refrigeration cycle. In addition to the TSL, a freezing / refrigeration switching switch SW contact is provided in series, and a refrigeration temperature control thermostat TSM is provided by bypassing the contact of the freezing / refrigeration switching switch SW. Another operating circuit is provided in parallel with the operating circuit that operates the solenoid valve SV1. The other operation circuit has contacts in series with ON / OFF of the freezing / refrigeration changeover switch SW, and is configured to operate the second solenoid valve SV2 in series.

Therefore, when the freezing / refrigerating changeover switch SW is ON and the temperature is not less than the setting of the refrigeration temperature control thermostat TSL, the compressor 1, the first solenoid valve 3 (S V1) and the second solenoid valve 6 ( SV2) is activated to cool the showcase and control the showcase for freezing.

When the freezing / refrigerating changeover switch SW is OFF, the freezing temperature adjusting thermostat TSL is always higher than the set temperature, so that it continues to be turned ON, and when the temperature rises from the setting due to the setting of the refrigerating temperature adjusting thermostat TSM. The compressor 1 and the first solenoid valve 3 (SV1) are operated, and the second solenoid valve 6 (SV2) is closed to allow the refrigerant gas to flow into the bypass circuit of the suction pressure adjusting valve 7. This suction pressure control valve 7 depressurizes the return refrigerant gas from the evaporator 5 to the compressor 1, which is in a light load condition of a showcase having a large capacity of refrigerant capacity, and has an appropriate suction pressure for the capacity of the refrigerator. It has the function of returning to an appropriate refrigeration cycle.

That is, according to the present invention, the second solenoid valve 6 (SV2) is provided between the evaporator 5 and the compressor 1 of the refrigeration cycle, and the suction pressure adjusting device 7 is bypassed by bypassing the second solenoid valve 6. When the switch SW is switched so as to operate the thermostat which is provided and set in the high temperature zone, the second solenoid valve 6 is closed to allow the refrigerant gas to flow into the suction pressure adjusting device 7 through the bypass circuit, and the suction refrigerant Is decompressed.

Therefore, even when the showcase having a large refrigerating capacity is switched to refrigerating which is a high temperature zone, the refrigeration cycle becomes appropriate by the suction pressure adjusting device 7, and the refrigerating temperature control thermostat TSL is provided near the evaporator 5. Even if a temperature sensing unit is installed, the temperature inside the showcase can be cooled to an appropriate set temperature without a sudden temperature change, causing a short cycle or starting / stopping the refrigerator (compressor) in a short time. It can be prevented from falling.

Further, since the refrigerant gas is prevented from returning to the compressor 1 with the high suction pressure, there is no possibility that the high pressure on the discharge side of the refrigerator becomes abnormally high and the pressure switch or the like operates. Therefore, it is possible to prevent a short cycle and an increase in high pressure, reduce the load on the refrigerator, and improve the life of the refrigerator.

In this embodiment, the suction pressure adjusting valve is used as the suction pressure adjusting device 7, but the suction pressure adjusting device is not limited to this, and the suction pressure adjusting device may be a structure capable of reducing the pressure such as a capillary tube. Can also be added.

[0020]

[Effect of device]

 As explained above, the refrigeration / refrigeration showcase is designed with the lowest refrigeration capacity among the switchable temperature zones with different temperature ranges. Although problems such as short cycle and high pressure rise occur due to imbalance between machine capacity and load, in the present invention, a solenoid valve is provided between the evaporator and the compressor of the refrigerant circuit, and this solenoid valve is bypassed. The suction pressure adjusting device is provided to allow the refrigerant to flow into the suction pressure adjusting device in cooperation with the temperature control device only when the temperature range is high. The refrigeration cycle can be maintained, short cycles and high pressure rise can be prevented, and the life of the refrigerator can be extended.

[Brief description of drawings]

FIG. 1 is a system diagram showing a refrigerant circuit of a showcase of the present invention.

FIG. 2 is a schematic view of a temperature control device of the present invention.

FIG. 3 is a system diagram showing a refrigerant circuit of a conventional showcase.

FIG. 4 is a schematic diagram of a conventional temperature control device.

[Explanation of symbols]

 1 Compressor 2 Condenser 3 First Solenoid Valve SV1 4 Expansion Valve 5 Evaporator 6 Second Solenoid Valve SV2 7 Suction Pressure Regulator CPR

Claims (3)

[Scope of utility model registration request] 1. In a temperature zone switching type showcase having a plurality of temperature control devices having different temperature ranges and capable of arbitrarily switching the temperature range, an electromagnetic valve is provided between the evaporator and the compressor of the refrigerant circuit, A temperature range characterized in that a suction pressure adjusting device is provided by bypassing the solenoid valve, and is linked to the temperature control device so that the refrigerant is switched to flow into the suction pressure adjusting device only when the temperature range is high. Switchable showcase. 2. The temperature zone switchable showcase according to claim 1, wherein the suction pressure adjusting device is a suction pressure adjusting valve. 3. The temperature zone switchable showcase according to claim 1, wherein the suction pressure adjusting device is a capillary tube.