JPH0451347Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a refrigerated open refrigerator that cools the inside of the case by isolating it from outside air by forming a cold air curtain in the opening for entering and exiting products formed on the front of the case. Regarding the refrigerant circuit of the case.

[Conventional technology]

In order to prevent a drop in cooling capacity, some such open refrigerator/freezer cases are equipped with two coolers to perform cooling and defrosting operations alternately. First, the overall structure is shown in Figure 2. To explain, it has an opening 2 on the front for entering and exiting products,
The case body 1 formed of a heat insulating wall is divided into a product storage 4 and a cold air circulation duct 6 by a duct plate 3, and a cold air circulation duct 6 and a protective air circulation duct 7 by a duct plate 5. The upper and lower ends of each are connected to air outlet ports 8, 9 and suction ports 10, 1.
1, and the inside of the cold air circulation duct 6 is further divided into two layers of passages 17a and 17b by a partition plate 16 to form a passage 17.
Coolers 18a and 18b are disposed inside a and 17b, respectively. In the figure, reference numerals 12 and 13 indicate blowers disposed in the cold air circulation duct 6 and the protective air circulation duct 7, respectively, and 14 and 15 indicate their fin guides.

In this way, the suction port 10,
The air sucked into the cold air circulation duct 6 and the protective air circulation duct 7 from 11 is cooled by the coolers 18a and 18b and becomes cold air, and the latter is blown out from the air outlets 8 and 9, respectively, and becomes cold air. A curtain and a protective air curtain are formed to close the opening 2.

By the way, the refrigerant circuits of the coolers 18a and 18b have conventionally been of various configurations, but basically, as shown in FIG.
d, compressor 19a, condenser 19b and liquid distillate 19c
are sequentially connected to form a condensing unit 19, and a refrigerant liquid pipe 40 is branched into two on the refrigerant discharge side of the condensing unit 19, that is, on the condenser 19b side, and is connected to the inlet side of the coolers 18a and 18b. The refrigerant inlet side, that is, the compressor 19a side, is connected to the outlet sides of the coolers 18a and 18b by refrigerant gas pipes 41, thereby forming a refrigeration cycle.

As a cooling circuit, electromagnetic valves 42a, 42b and expansion valves 43a, 43b are provided in the middle of the refrigerant liquid pipe 40 near the coolers 18a, 18b, respectively. Solenoid valves 44a and 44b are provided in the middle of the gas pipe 41.

In addition, as a defrosting circuit, the refrigerant discharge side of the compressor 19a and the coolers 18a, 18b are separately connected with a refrigerant pipe 45, and solenoid valves 46a, 46b are provided in the middle, and the inlet side of the coolers 18a, 18b is connected separately. , solenoid valves 42a, 42b and expansion valves 43a, 43
Refrigerant liquid pipes 47a and 47b are provided to bypass the refrigerant pipes b, and check valves 48a and 48b are provided here, respectively.

In this way, the coolers 18a and 18b are
Basically, for cooling operation, solenoid valve 4 in the defrosting circuit is required.
If 6a and 46b are closed and 42a and 42b are left open, the liquid refrigerant compressed to high temperature and high pressure by the compressor 19a and liquefied by the condenser 19b enters the cooling circuit and flows through the electromagnetic valves 42a and 42b and the expansion valves 43a and 43b. The refrigerant enters the coolers 18a and 18b through the air blower 12, where it exchanges heat with the air sent by the blower 12, evaporates, and passes through the refrigerant gas pipe 41 to the accumulator 19d and compressor 19a in the condensing unit 19.
The refrigeration cycle is thus formed.

By the way, during the cooling operation, the coolers 18a and 18b
In order to remove this frost, the moisture contained in the air sucked into the cooler 18 becomes frost and adheres here, blocking ventilation and reducing the cooling effect.
The cooling operation of the a and 18b is stopped alternately and the defrosting operation is performed. To perform this defrosting operation,
For example, when defrosting the cooler 18a side, open the defrosting solenoid valve 46a in the middle of the refrigerant pipe 45, and close the solenoid valve 44a in the middle of the refrigerant gas pipe 41 and the solenoid valve 42a in the middle of the refrigerant liquid pipe 40. The high-temperature, high-pressure refrigerant that exits the compressor 19a does not enter the condenser 19b, but passes through the refrigerant pipe 45 and enters the cooler 18a from the defrosting circuit, and is attached to the cooler 18a due to the heat held by this refrigerant. Melt the frost. The liquid refrigerant that has passed through the cooler 18a is passed through the refrigerant liquid pipe 47 via the check valve 48a.
a, and then enters the cooler 18b through the electromagnetic valve 42b and expansion valve 43b on the other cooler 18b side, where it performs a cooling action.

It should be noted that not all of the refrigerant discharged from the condensing unit 19 is supplied from the compressor 19a to the cooler 18a during defrosting, but some of it passes through the condenser 19b and is sent from the liquid distillate 19c to the refrigerant pipe. 40 and is directly supplied to the cooler 18b which is in cooling operation.

In this way, switching between defrosting and cooling operation is performed using the solenoid valves 42a, 42b, 44a, 44b, 46a, 46.
When one cooler, for example 18a, enters defrosting operation, the defrosting circuit of cooler 18a that defrosts and the cooling circuit of the other cooler 18b that continues cooling operation. and condensing unit 19
The refrigerant sent out from the compressor 19a of the condensing unit 19 is first supplied to the cooler 18a that performs defrosting, and then the refrigerant is supplied to the cooler 18b that performs cooling operation via this. I have to.

[Problem that the invention attempts to solve]

For this reason, the temperature of the refrigerant supplied to the cooler 18b that continues the cooling operation varies depending on the amount of frost on the cooler 18a, and it may be difficult to obtain the prescribed cooling capacity in the cooler 18b. In order to obtain sufficient cooling capacity, it is necessary to use a large-sized cooler.

As a result, the space in the product storage 4 becomes narrower.

If the cooler is downsized to eliminate this inconvenience, the evaporation temperature of the cooler must be lowered to obtain the required cooling capacity, and as a result, the amount of frost on the cooler increases, further reducing the load. Sometimes problems such as so-called stagnation of refrigerant occur in compressors and the like.

Further, since defrosting is performed using the high temperature and high pressure refrigerant discharged from the compressor 19a as a heat source, the temperature inside the refrigerator increases significantly, which may reduce the quality of stored products.

The purpose of the present invention is to eliminate the disadvantages of the conventional example,
To provide a refrigerant circuit for a freezer/refrigerator open case, which can miniaturize a cooler without reducing cooling capacity and can suppress the rise in internal temperature during defrosting operation.

[Means for solving problems]

In order to achieve the above object, the present invention provides a refrigerated open storage case in which two coolers are installed in the cold air circulation duct provided inside the storage case body, and these coolers are operated alternately for cooling and defrosting. , an accumulator, a compressor, a condenser, and a liquid distillate are connected in sequence to form a condensing unit, and for cooling, the liquid distillate side of this condensing unit is connected to the inlet side of each cooler with a refrigerant liquid pipe. A solenoid valve and an expansion valve are respectively arranged near the cooler inlet of the refrigerant liquid pipe, a refrigerant discharge pipe provided with a solenoid valve is connected to the outlet side of the cooler, and the refrigerant discharge pipe is connected to an accumulator. It is connected to a refrigerant gas pipe to form a cooling circuit.On the other hand, for defrosting, the liquid reservoir side of the condensing unit is connected to a cooler with a defrosting refrigerant liquid pipe equipped with a solenoid valve, and the refrigerant outlet of the cooler is The gist is that defrosting refrigerant discharge pipes each provided with a pressure reducing valve that bypasses the refrigerant discharge pipe and serves as a pressure reducing part are connected to the side, and the other end of the discharge pipe is connected to the refrigerant gas pipe. It is something.

[Effect]

According to the present invention, when one of the two coolers is in defrosting operation and the other is in cooling operation, the condenser is connected to the cooler to be defrosted via the defrosting circuit. Refrigerant is supplied from the side, and its latent heat of condensation melts the frost adhering to the cooler. The refrigerant exiting the cooler is depressurized in the decompression section of the refrigerant discharge circuit for defrosting, and then sucked into the compressor again. On the other hand, refrigerant is directly supplied from the condenser to the cooler that continues the cooling operation, as in the case of the two-unit cooling operation.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a refrigerant circuit diagram of the refrigerated open-shelf case of the present invention, and the overall structure of the open-shock case of the refrigerated-freezer in which the refrigerant circuit of the present invention is used is the same as that already explained with reference to FIG. Detailed explanation here will be omitted.

In the figure, numeral 19 indicates a condensing unit, in which an accumulator 19d, a compressor 19a, a condenser 19b, and a liquid distillate 19c are sequentially connected as in the conventional case. The refrigerant liquid pipes 20 are connected to the respective coolers 18a and 18b, and near the inlets of the coolers 18a and 18b of the refrigerant liquid pipes 20, solenoid valves 21a and 21a are connected.
21b and expansion valves 22a and 22b were respectively arranged to form a cooling circuit. and coolers 18a, 18
Refrigerant discharge pipes 24a and 24b having electromagnetic valves 23a and 23b provided in the middle thereof were connected to the outlet side of b, and the refrigerant discharge pipes 24a and 24b were connected to a refrigerant gas pipe 30 connected to an accumulator 19d. Note that the refrigerant discharge pipes 24a, 24b and the refrigerant gas pipe 30 may be configured as an integral continuous pipe.

On the other hand, for defrosting, the liquid distillate 19c side of the condensing unit 19 is branched into two in the middle and connected to the coolers 18a and 18b by a defrosting refrigerant liquid pipe 25 which is provided with solenoid valves 26a and 26b on the downstream side. Also, cooler 1
The refrigerant discharge pipe 2 is provided on the refrigerant outlet side of 8a, 18b.
Defrosting refrigerant discharge pipes 28a, 28b are connected, which are provided with pressure reducing valves 27a, 27b, which serve as pressure reducing parts by bypassing the defrosting refrigerant discharge pipes 28a, 24b.
The other end of 28b is connected to the refrigerant gas pipe 30.

In the figure, 29 is the electromagnetic valve 21a, 21b, 23.
a, 23b, 26a, 26b and pressure reducing valve 27a,
This is a control device that controls opening and closing of 27b.

Next, a method for controlling the operation of a frozen/refrigerated open case using such a refrigerant circuit will be explained according to the time chart of FIG.
The cooling/defrosting operation of 8a and 18b is performed by the control device 29.
Each solenoid valve 21 is activated at each time set here by the function of
a, 21b, 23a, 23b, 26b, 26b,
This is done by opening and closing the reduced pressure 27a, 27b. First, the coolers 18a, 18b are opened and closed.
To perform cooling operation, the solenoid valves 21a, 21b, 23a, and 23b are opened by the control device 29.
If the solenoid valves 26a, 26b and the pressure reducing valves 27a, 27b are closed, the liquid refrigerant compressed to high temperature and high pressure by the compressor 19b and discharged from the condenser 19b enters the cooling circuit and flows through the solenoid valves 21a, 21b and the expansion valve 22.
The refrigerant enters the coolers 18a and 18b via the air conditioners 18a and 22b, where it exchanges heat with the air sent here by the blower 12, evaporates, and flows into the refrigerant discharge pipe 2.
4a and 24b, and returns to the accumulator 19d and compressor 19a in the condensing unit 19 through the refrigerant gas pipe 30, thus forming a refrigeration cycle.

By the way, during the cooling operation, the coolers 18a and 18b
In order to remove this frost, the moisture contained in the air sucked into the cooler 18 becomes frost and adheres here, blocking ventilation and reducing the cooling effect.
The cooling operation of the a and 18b is stopped alternately and the defrosting operation is performed. To perform this defrosting operation,
For example, when defrosting the cooler 18a side, the solenoid valves 21a and 23a in the cooling circuit of the cooler 18a side
Close the solenoid valve 26a and pressure reducing valve 27 in the defrosting circuit.
The other cooler 18 opens and continues cooling operation.
The solenoid valves 21b, 23b, 26b and pressure reducing valve 27b on the b side are left as they are.

As a result, the liquid distillate 19c passes through the defrosting refrigerant liquid pipe 25 to the cooler 18a that performs the defrosting operation.
A 35° C. refrigerant condensed gas or refrigerant condensate is supplied, and although the temperature is lower than the discharge gas discharged from the compressor 19a, the condensation heat of this refrigerant melts the frost adhering to the cooler 18a. Then, the refrigerant that has exited the cooler 18a enters the defrosting refrigerant discharge pipe 28a, is reduced in pressure by a pressure reducing valve 27a provided here, expands, is vaporized, and returns to the accumulator 19d.

At this time, the other cooler 18b is continuing the refrigeration cycle at the same time as the cooling operation by the two coolers, and the cooler 18a during defrosting is discharging relatively low-temperature condensation heat as described above. Since the temperature inside the refrigerator is kept low during this period, the quality of stored products does not deteriorate.

When the time set in the control device 29 has elapsed, the two coolers 18a and 18b enter the cooling operation again, and then the cooler 18b side enters the defrosting operation.

In this way, the cooler 18a enters the defrosting operation.
Or 18b includes a cooler 18 that continues the cooling operation.
A separate defrosting circuit independent from the b or 18a side is formed, and the two coolers 18a and 18b are connected in parallel to the condensing unit 19, and the refrigerant discharged from the cooler 18a or 18b to be defrosted is , directly returns to the condensing unit 19 without entering the other cooler 18b or 18a.

In addition, although the case where a pressure reduction valve is provided as a pressure reduction part was demonstrated in the said Example, it is not limited to this, and it is also possible to arrange|position an electromagnetic valve and a pressure reduction pipe.

[Effect of idea]

As described above, when two coolers are installed and the refrigerant circuit of the open storage refrigerator case of the present invention is used for defrosting and cooling operations alternately, the defrosting circuit of the cooler that defrosts and the cooling circuit of the other cooler that performs cooling are used. The cooling circuit of the cooler is connected in parallel to the condenser unit, so the refrigerant from the cooler that performs defrosting does not enter the other cooler, so the cooler that continues cooling operation Refrigerant in the same state as when the two units are in cooling operation continues to be supplied, and as a result, there is no change in cooling capacity, there is no need to make the cooler particularly large, and sufficient space can be secured inside the refrigerator. .

In addition, since defrosting is performed using the heat of condensation of the refrigerant coming out of the condenser as a heat source, compared to using the discharge gas from the compressor, defrosting is performed using a low-temperature source while ensuring the amount of heat necessary for defrosting. It is possible to suppress the rise in temperature inside the refrigerator during frost, and prevent the quality of stored products from deteriorating.

[Brief explanation of the drawing]

Figure 1 is a refrigerant circuit diagram of the open refrigerator/freezer case of the present invention, Figure 2 is a longitudinal cross-sectional side view of the open refrigerator/refrigerator case, Figure 3 is a time chart showing the opening and closing of valves, and Figure 4 is a refrigerant circuit diagram of the conventional refrigerant. It is a circuit diagram. 1...Show case body, 2...Opening, 3...
... Duct plate, 4 ... Product storage, 5 ... Duct board, 6 ... Cold air circulation duct, 7 ... Protective air circulation duct, 8, 9 ... Air outlet, 10, 11 ... Suction port, 12, 13...Blower, 14,15...Fan guide, 16...Dividing board, 17a, 17b...
Passage, 18a, 18b...Cooler, 19...Condensing unit, 19a...Compressor, 19b...Condenser, 19c...Liquid distiller, 19d...Accumulator, 20...Refrigerant liquid pipe, 21a, 21b... ...Solenoid valve, 22a, 22b...Expansion valve, 23a, 23b
... Solenoid valve, 24a, 24b ... Refrigerant discharge pipe, 2
5... Defrosting refrigerant liquid pipe, 26a, 26b... Solenoid valve, 27a, 27b... Pressure reducing valve, 28a, 28b
... Defrosting refrigerant discharge pipe, 29 ... Control device, 30
... Refrigerant gas pipe, 40 ... Refrigerant liquid pipe, 41 ... Refrigerant gas pipe, 42a, 24b ... Solenoid valve, 43a,
43b...expansion valve, 44a, 44b...electromagnetic valve,
45... Refrigerant pipe, 46a, 46b... Solenoid valve, 4
7a, 47b... Refrigerant liquid pipe, 48a, 48b...
non-return valve.

Claims (1)

[Scope of Claim for Utility Model Registration] In an open refrigerated storage case in which two coolers are installed in a cold air circulation duct provided in the storage case body and these coolers are operated alternately for cooling and defrosting, an accumulator is provided. , a compressor, a condenser, and a liquid distillate are connected in sequence to form a condensing unit, and for cooling, the liquid distillate side of this condensing unit is connected to the inlet side of each cooler with a refrigerant liquid pipe.
A solenoid valve and an expansion valve are each arranged near the cooler inlet of the refrigerant liquid pipe, a refrigerant discharge pipe provided with a solenoid valve is connected to the outlet side of the cooler, and the refrigerant discharge pipe is connected to an accumulator. It is connected to a refrigerant gas pipe to form a cooling circuit.On the other hand, for defrosting, the liquid reservoir side of the condensing unit is connected to a cooler with a defrosting refrigerant liquid pipe equipped with a solenoid valve, and the refrigerant outlet of the cooler is Defrosting refrigerant discharge pipes each having a pressure reducing valve that bypasses the refrigerant discharge pipe and serves as a pressure reducing part are connected to the side, and the other end of the discharge pipe is connected to the refrigerant gas pipe. Refrigerant circuit of open refrigeration case.