JPS6252374A - Defroster for refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a 7A defrosting device for a refrigeration system, and particularly relates to a defrosting device for a refrigeration system whose defrosting mechanism is improved by adopting a proportional expansion valve. It is something.

[Technical Background of the Invention and Problems Therewith] Generally, a refrigeration cycle for cooling a refrigeration system consists of a compressor 1. Condenser 2. Expansion valve 3. A refrigeration vehicle 5 is formed by sequentially connecting M generators 4 in series.

Conventionally, this refrigeration cycle 5 includes a bypass refrigerant passage 8 that is branched from a refrigerant passage 6 on the inlet side of the condenser 2 via a two-way valve 7 and connected to the refrigerant passage 6 on the inlet side of the evaporator 4. A snow removal device 11 was constructed by interposing an electromagnetic opening m valve 9 and a drain dish heating vibrator 10 in this bypass cold tofu passage 8.

In operation of the refrigeration cycle 5 having the defrosting Rfa11, the two-way valve 7 changes the flow of refrigerant between the cooling operation and the defrosting operation. Due to the structure of the refrigeration cycle 5, the drain dish heating pipe 10 was constructed so that cold tofu (high temperature) only flowed during defrosting. The expansion mechanism employed the expansion valve 3 or the '1:1t pillar tube (not shown).

However, this conventional defrosting device for a refrigeration system has the following problems.

Since the drain tray was cooled during the cooling operation, there was a risk of ice remaining during the defrosting operation.

Further, there was a problem in that the piping between the refrigeration cycle 5 and the snow removal device 11 on the condenser 2 side and the evaporator 4 side was difficult, making the refrigeration cycle 5 complicated.

Furthermore, the opening degree of the expansion valve 3 could not be adjusted according to the refrigeration load.

Furthermore, as mentioned above, the refrigeration cycle 5 is complicated, so there is a problem that the manufacturing cost is high.

[Object of the Invention] The present invention was devised to solve 14 problems in defrosting devices of refrigeration equipment.

An object of the present invention is to provide a defrosting device for a refrigeration system that has a simple structure, can achieve efficient defrosting, and is inexpensive.

[Summary of the Invention] In order to achieve the above object, the present invention provides a refrigerant passage connecting a condenser and an evaporator that constitute a refrigeration cycle, with a proportional valve opening that is proportional to the refrigeration load. In addition to providing an expansion valve, the configuration includes a defrosting circuit that opens the proportional expansion valve during defrosting and allows hot gas to flow through the evaporator from the condenser side, and the defrosting circuit connects the condenser and evaporator. By detecting that the heat exchange has been stopped and opening the proportional expansion valve, hot gas from the condenser flows into the evaporator, which is highly efficient in a defrosting device with a cylinder structure. Defrosting has been achieved and H-3I! This allows reduction of I-1 stroke.

[Embodiments of the invention] Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the invention.

As shown, compressor 1. Condenser 2. A proportional expansion valve 12 is interposed in a refrigerant passage 6 connecting the condenser 2 and the evaporator 4 of a refrigerating system 5 of a normal refrigeration system having an evaporator 4 . The proportional expansion valve 12 is configured to proportionally adjust its valve opening depending on the refrigeration load and control the refrigerant flow rate of the refrigeration cycle 5. This proportional expansion valve 12 is equipped with a defrosting circuit 13. Further, on the upstream side of the proportional expansion valve 12 provided in the refrigerant passage 6 connecting the condenser 2 and the evaporator 4, a drain dish heating vibe 15 equipped with a power storage device 14 is provided. It is located below the evaporator 4. Furthermore, this drain dish heating pipe 1
The above condensation is in the refrigeration cycle 5 on the upstream side of 5! A defrosting refrigerant passage 16 connected from the inlet side to the outlet side of the defrosting refrigerant passage 16 is provided, and an electromagnetic on-off valve 17 is interposed in this defrosting refrigerant passage 16. Furthermore, the defrosting circuit 13 is connected to the air blower -18°19 provided in the condenser 212 and the evaporator 4, respectively, and is also connected to the electromagnetic on-off valve 17 and is electronically controlled. A defrosting device 11 of the refrigeration system is configured.

Next, the operation of the first embodiment will be described.

During cooling operation, the electromagnetic on-off valve 17 provided in the defrosting refrigerant passage 16 is closed. The refrigerant compressed by the compressor 1 passes through the condenser 2 and is then passed through the drain plate heating pipe 15.
and reaches the power accumulator 14, is evaporated in the evaporator 4 and absorbs heat,
Run cooling operation. At this time, the proportional expansion valve 12 is superheated by the defrosting circuit 13 to keep the degree of superheat constant.

Next, during defrosting operation, when the evaporator 4 is frosted and the defrosting signal is detected, the defrosting circuit 13 detects the electromagnetic amount
1 valve 17 and proportional expansion valve 12 are controlled to be fully open, and heat exchange between the condenser 2 and evaporator 4 is stopped. Then, the hot gas flows into the evaporator 4 to perform defrosting. Note that defrosting is terminated using a temperature pin (not shown) installed near the evaporator 4 outlet.

By operating in this way, 3.
Since the drain tray heating pipe 15 is maintained at a high temperature with a refrigerant of approximately 0 to 40° C., the drain tray is constantly heated and freezing of the drain tray is prevented. In addition, a supercooling effect occurs in the drain dish heating vibrator 15, and the refrigerating capacity E
ER will improve. Furthermore, during the defrosting operation, the drain tray heating pipe 15 becomes even hotter, and the drain tray is completely defrosted.

Next, FIG. 2 shows a second embodiment.

As shown in the figure, in this embodiment, a defrosting refrigerant passage in which a drain heating pipe 15 equipped with a power storage device 14 of the refrigeration cycle 5 in the first embodiment and an electromagnetic shut-off valve 17 are interposed. Defrosting device 11 with simplified structure by removing 16 and 11
It is.

Regarding the operation of the second embodiment, as in the first embodiment, the opening degree of the proportional expansion valve 12 is proportionally controlled by the defrosting circuit 13 during cold r4I operation, and the outlet temperature of the proportional expansion valve 12 is controlled proportionally. The temperature difference between the temperature of the evaporator 4 and the temperature of the evaporator 4 is kept constant. Further, during defrosting operation, the defrosting circuit 13 fully opens the proportional expansion valve 12, and the heat exchange between the condenser 2 and the evaporator 4 is stopped, so that the hot gas is transferred to the evaporator. 4 and is defrosted.

In this way, according to the second embodiment, the structure of the refrigeration cycle 5 including the defrosting device 11 is simplified, and the opening degree of the proportional expansion valve 12 during defrosting operation is set by the defrosting circuit 13. By doing so, the refrigerant flow rate can be controlled. In addition, in this embodiment, a demand defrost method may be adopted in addition to interlocking with a defrost timer (not shown). Furthermore, the valve opening degree of the proportional expansion valve 12 is not limited to full opening, but may be controlled by sensing low pressure, a pressure, etc.

Next, FIG. 3 shows a third embodiment.

As shown in the figure, the third embodiment has a thermistor sensor installed in the refrigerator interior 20 of the refrigeration cycle 5 shown in the second embodiment.
i and a thermistor sensor TII at the outlet of the proportional expansion valve 12.
A thermistor sensor Tll5 is provided at the outlet of Q and evaporation @4.

The operation of the third embodiment will be described below.

The temperatures sensed by the thermistor sensors THe and Tll5 are taken as Te and Ts, respectively. As shown in FIG. 4, during cooling operation, the relationship between the temperature inside the refrigerator 20, the outlet temperature Te of the proportional tension valve 12, and the outlet temperature 1fTs of the evaporator 4 is such that as the temperature inside the refrigerator 20 decreases, Ts and Te also decrease. Go down.

At this time, the valve opening degree X of the proportional expansion valve 12 is the temperature difference ΔT (Ts
-Te) is controlled so that it is always constant. That is, during cooling operation, the degree of superheat (ΔT-TS-TO) is kept constant. Moreover, FIG. 5 is an operation state diagram of the compression Ia1 and the valve opening degree of the proportional expansion valve 12 when the temperature inside the refrigerator 20 is 11111. The temperature inside the refrigerator 20 is controlled by the refrigerator interior 20.
It is controlled by a thermistor sensor Tl1i that senses the air temperature. That is, during the cooling operation, the compressor 1 is turned on (ON).
), and the valve opening X of the proportional expansion valve 12 is ΔT as described above.
= Controlled to be constant. At the same time as the temperature inside the refrigerator 20 decreases and reaches the preset temperature Tea,
With the valve opening degree (x=0), that is, fully closed, the compressor 1 continues to be driven (ON) for a period of time t[, and the time tf
After the time has elapsed, the compressor 1 is set to stop (OFF). When the temperature inside the refrigerator 20 reaches the set humidity Tea or higher, the cooling operation is performed again as described above (pump down control).
. If the minimum stop time is ts, the drive of the compressor 1 (
ON) time [f is set to a time shorter than the minimum stop time tm.

In addition, when the drive (ON) signal of the compression fi1 is transmitted, the proportional expansion valve 12 is controlled to be fully open for tv seconds in order to balance the pressure, and then the compressor 1 is driven (ON). Ru.

As described above, since the superheat degree is constant control system, efficient cooling operation is achieved, and it can be applied even in cases where there are severe load fluctuations, and energy saving can be achieved.

In addition, the structure is simple as thermistor sensors Ttle, Tl1s and Tl1i are provided independently of the proportional expansion valve 12, and serviceability is improved.

Furthermore, matching of the refrigeration cycle 5 can be easily done by setting the degree of superheating and selecting the gasification.

Furthermore, due to the pump down control 311 and the balancing action,
The starting load on the compression unit 11 can be reduced and energy savings can be achieved.

And, even without providing a particular balancing circuit, the proportional expansion valve 12
By fully opening the valve, the pressure can be balanced.

[Effects of the Invention] In summary, the present invention exhibits the following excellent effects.

(1) A proportional expansion valve is installed in the refrigerant passage connecting the condenser and evaporator to proportionally adjust the opening of the valve according to the refrigeration load, eliminating the need for a bypass cold storage passage like in the past.
The structure of the refrigeration cycle can be easily constructed.

(2) By setting the opening of the proportional expansion valve that is turned on during defrosting, the flow of bot gas can be controlled and efficient TI removal operation can be achieved.

(3) As mentioned in item (1), since the structure is simple, the manufacturing cost can be reduced and an inexpensive defrosting device can be obtained.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing the first embodiment of the present invention, Fig. 2 is a system diagram showing the second embodiment of the invention, and Fig. 3 is a system diagram showing the third embodiment of the invention. , Fig. 4 is a diagram of the relationship between the temperature detected by the sensor during operation of the third embodiment, the valve opening of the proportional expansion valve, and the temperature inside the refrigerator, and Fig. 5 shows the compressor and the proportional expansion valve when controlling the temperature inside the refrigerator. FIG. 6 is a system diagram showing a conventional example. In the figure, 2 is a condenser, 4 is an evaporator, 5 is a refrigeration cycle, and 6
1 is a refrigerant passage, 11 is a T1 device, 12 is a proportional expansion valve, 1
3 is a defrosting circuit. Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A proportional expansion valve is installed in the refrigerant passage connecting the condenser and evaporator that make up the refrigeration cycle, and the opening degree of the valve is adjusted proportionally according to the refrigeration load. A defrosting device for a refrigeration system, characterized in that a defrosting circuit is provided in the container to allow hot gas to flow from the condenser side.