JPS62196582A - 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 [Industrial Field of Application] The present invention relates to a refrigeration device such as a freezer/refrigeration showcase, and particularly to one with improved defrosting operation.

[Conventional technology]

Such a refrigeration system generally has a compressor (1), a water-cooled condenser (2), a pressure reducing device (3), an evaporator (4), and an accumulator (5) connected in sequence, as shown in FIG. A refrigeration cycle is constructed, and the water-cooled condenser (2) is provided with a water inlet (7) and a water outlet of a cooling water pipe, and although not shown, the evaporator (4) is provided with a cooling water pipe for forced cold air. A blower is attached.

Furthermore, for defrosting, the refrigerant outlet side of the compressor (1) and the refrigerant outlet side of the pressure reducing device (3) are connected by a bypass circuit (6), in which a solenoid valve (6a) for gas refrigerant control is interposed. let me,
A solenoid valve (7) for controlling cooling water may be provided at the water inlet of the water-cooled condenser (2).

During cooling operation, the solenoid valve (7) at the water inlet of the water-cooled condenser (2) is opened, and at the same time, the solenoid valve (6a) of the bypass circuit (6) is closed to discharge water from the compressor (1). The high-temperature, high-pressure refrigerant gas thus produced is circulated in the direction of the solid line arrow in FIG. In this case, the high temperature and high pressure refrigerant gas is condensed and liquefied in the water-cooled condenser (2), and the heat of condensation released at this time is sucked into the water in the cooling water pipe.

Then, the liquefied refrigerant liquid at room temperature and normal pressure is depressurized in the vacuum bag W (3) to become a low-salt, low-pressure refrigerant liquid and sent to the condenser (2), where it passes through the refrigerant piping in the condenser (2). However, the heat required for evaporation is absorbed from the surrounding air, which cools the surrounding air, which is then forced into the showcase using a blower.

The refrigerant gas at normal temperature and normal pressure, which is almost vaporized in the condenser (4), is sent to the accumulator (5), where it is further vaporized and gas-liquid separated, and only the refrigerant gas is sent to the compressor (1).
), where it is compressed and raised to high temperature and pressure.

By the way, in the cooling operation described above, when the low-temperature, low-pressure refrigerant gas vaporizes in the evaporator (4), it cools the surrounding air, so the moisture contained in the cooled surrounding air turns into frost. and adheres to the surface of the evaporator (4). As this frost thickens, the cooling power of the evaporator (4) decreases, so it becomes necessary to switch the cooling operation to the defrosting operation.

To start such defrosting operation, the solenoid valve (7) at the water inlet of the water-cooled condenser (2) is closed and the solenoid valve (6a) of the bypass circuit (6) is opened. The high-temperature, high-pressure refrigerant gas discharged from the machine (1) is circulated in the direction of the broken line arrow in FIG.

At this time, the high temperature and high pressure refrigerant gas discharged from the compressor (1) flows into the condenser (2) in that state, so its latent heat melts and removes the frost on the surface of the evaporator (4). Do frost.

The refrigerant gas that has flowed into the evaporator (4) is cooled and liquefied, but since the temperature and pressure were high, the liquefaction is incomplete and it flows into the accumulator (5), where it is separated into a gas-liquid mixture and becomes liquid. The gas remains in the accumulator (5) and only the refrigerant gas is sucked into the compressor (1).

When defrosting is completed, open the solenoid valve (7) at the water inlet of the water-cooled condenser (2), and close the solenoid valve (7) in the bypass circuit (6).
If 6a) is closed, the defrosting operation is switched to the cooling operation.

[Problem that the invention seeks to solve]

In this way, at the start of defrosting operation, the solenoid valve (7) at the water inlet of the water-cooled condenser (2) is closed, and at the same time the bypass circuit (6) is closed.
When the solenoid valve (6a) is opened, most of the high-temperature, high-pressure refrigerant gas discharged from the compressor (1) heads to the bypass circuit, and a portion flows out toward the water-cooled condenser (2). At that time, water cooling of the water-cooled condenser (2) is stopped, so the inside of the water-cooled condenser (2) is not cooled and is maintained at a high temperature.

However, in this state, the high-temperature, high-pressure refrigerant gas is difficult to be sucked in and is gradually discharged toward the solenoid valve (6a) of the bypass circuit (6). As a result, the amount of high-temperature, high-pressure refrigerant gas passing through the solenoid valve (6a) gradually increases, and accordingly, the amount of refrigerant liquid that is defrosted and liquefied in the evaporator (4) also gradually increases. The limit of the gas-liquid separation capacity of the rotor (5) is exceeded, and a so-called liquid return phenomenon occurs in which the refrigerant liquid is also sucked into the compressor (1).

This may shorten the life of the compressor (1), and in order to solve this problem, it is possible to increase the size of the accumulator (5) and increase its gas-liquid separation capacity. There was a problem with this, which led to the equipment itself becoming larger.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the disadvantages of the conventional example and to provide a refrigeration system that can prevent refrigerant from being sucked into the compressor even in a refrigeration system equipped with a small accumulator.

[Means for solving problems]

In order to achieve the above object, the present invention constitutes a refrigeration cycle by sequentially connecting a compressor, a water-cooled condenser, a pressure reducing device, an evaporator, and an accumulator, and the refrigerant outlet side of the compressor and the refrigerant outlet of the pressure reducing device In a refrigeration system in which a solenoid valve is connected to the side by a defrosting bypass circuit with an intervening solenoid valve, the solenoid valve opens at the water inlet of a water-cooled condenser and then closes a while after the solenoid valve closes. The gist is that a solenoid valve is provided that opens at the same time.

[Effect]

According to the present invention, both the solenoid valve at the water inlet of the water-cooled condenser and the solenoid valve in the bypass circuit are opened for the initial setting time of the defrosting operation, thereby controlling the temperature of the water-cooled condenser during that time. Since the pressure is lowered, high-temperature, high-pressure refrigerant gas is prevented from being discharged in the opposite direction from the water-cooled condenser, and the amount of liquefaction in the evaporator is prevented from increasing by more than one unit.

Furthermore, by matching the reverse operation, the amount of liquefaction in the evaporator is held down to a constant amount, while waiting for the end of defrosting, the solenoid valve at the water inlet of the water-cooled #@ container and the solenoid in the bypass circuit are Switch to cooling operation by opening and closing the valve. This prevents refrigerant liquid from being sucked into the compressor from the accumulator during defrosting.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

The present invention sequentially connects a compressor (1), a water-cooled condenser (2), a pressure reducing device (3) such as an expansion valve, an evaporator (4), and an accumulator (5) as shown in FIG. A refrigeration cycle is configured, and a water cooling A specific solenoid valve (7) was installed at the water inlet of the type condenser (2).

Based on the operation timer 1- in Fig. 1, the operation of the solenoid valve (7) will be mainly explained. In the diagram, the hatched time period indicates the opening of the solenoid valve (6a>(7)). .

In the cooling operation, when defrosting is finished, the cooling water solenoid valve (7) is opened and the high-temperature, high-pressure refrigerant gas solenoid valve (6a) is closed. The operation of the refrigeration system during cooling operation is exactly the same as in the conventional example, so the explanation will be omitted.

Next, to explain the defrosting operation, when defrosting starts, the cooling water solenoid valve (7) is kept open for a while without sending a close signal according to the settings of the timer, etc. A signal is sent to the solenoid valve (6a) for high-temperature, high-pressure gas to close it.

Then, a part of the high-temperature, high-pressure refrigerant gas discharged from the compression 1J3i (1) passes through the solenoid valve (6a) of the bypass circuit and flows into the evaporator (4), but the rest flows into the water-cooled condenser (
2), where it is water-cooled to become a room-temperature, high-pressure refrigerant liquid, and then passes through the pressure reducing device (3) to become a low-temperature, low-pressure refrigerant liquid that flows into the evaporator (4), where it evaporates. The amount of refrigerant that flows into the accumulator (5) as a refrigerant liquid is extremely small.

On the other hand, the refrigerant gas that has passed through the solenoid valve (6a) as a high-temperature, high-pressure refrigerant gas flows into the evaporator (4), radiates heat for defrosting, and liquefies. (5), where the stream is separated. Therefore, after setting an appropriate time in consideration of the gas-liquid separation capacity of the accumulator (5), the solenoid valve (7) at the water inlet of the water-cooled condenser (2) is closed by a signal. The introduction of cooling water to the water-cooled condenser (2) is stopped, and heat dissipation by the cooling water is stopped, so the flow of high temperature and high pressure refrigerant gas discharged from the compressor (1) to the water-cooled condenser (2) is stopped. People are blocked, and most high-temperature, high-pressure refrigerant gas is bypassed (6)
It passes through the solenoid valve (6). As a result, the amount of high-temperature, high-pressure refrigerant gas liquefied in the evaporator (4) is a constant amount, and the defrosting time is set so that it stays within the range of the gas-liquid separation capacity of the accumulator (5). Open the solenoid valve (7) at the water inlet of the type condenser, and close the solenoid valve (6a).

In this way, the refrigerant liquid is not sucked into the compressor (1) from the accumulator (5), and the defrosting operation is switched to the cooling operation.

〔Effect of the invention〕

As described above, the refrigeration system of the present invention configures a refrigeration cycle by sequentially connecting a compressor, a water-cooled condenser, a pressure reducing device, an evaporator, and an accumulator. In a refrigeration system in which the refrigerant outlet side is connected to the refrigerant outlet side by a defrosting bypass circuit with a solenoid valve, the amount of refrigerant liquefied in the evaporator is constant during defrosting operation, and the gas-liquid separation capacity of the accumulator is Since defrosting can be completed within this range, the inconvenience of so-called liquid return, where liquid refrigerant is sucked into the compressor from the accumulator, is also eliminated. As a result, the life of the compressor can be extended. Furthermore, since the above-mentioned defrosting operation is possible even with a small accumulator within its gas-liquid separation capacity, there is also the effect that the refrigeration apparatus can be made smaller.

[Brief explanation of drawings]

FIG. 1 is an operation time chart showing an embodiment of the refrigeration system of the present invention, FIG. 2 is a program diagram of the refrigeration system, and FIG. 3 is an operation time chart showing a conventional example. (1)...Compressor (2)...Water-cooled condenser (
3)...Pressure reduction device (4)...Evaporator (5)...
・Accumulator (6)...Bypass circuit (6a)...Solenoid valve (7)
...Solenoid valve agent Patent attorney Masuo Oono Figure 1 Darkness Otakoryo

Claims (1)

[Claims] A refrigeration cycle is constructed by sequentially connecting a compressor, a water-cooled condenser, a pressure reducing device, an evaporator, and an accumulator. In the refrigeration system connected by a frost bypass circuit, a solenoid valve is provided at the water inlet of the water-cooled condenser, which closes after a while after the solenoid valve opens, and opens at the same time as the solenoid valve closes. refrigeration equipment.