JPS62223570A - Method of controlling operation of 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 Application Field] The present invention relates to operational control of refrigeration equipment such as freezer/refrigerated showcases, and particularly to improved defrosting operation.

[Conventional technology]

Generally, as shown in FIG. 2, such a refrigeration system connects a compressor (1), a water-cooled condenser (2), a pressure reducing device (3), an evaporator (4), and an accumulator (5) with refrigerant piping in sequence. A refrigeration cycle is constructed, and the water-cooled condenser (2
) is provided with a water inlet and a water outlet for the cooling water pipe.
Although not shown, the evaporator (4) is equipped with a blower for forced cold air.

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 pipe (6), and a solenoid valve (6a) for gas refrigerant control is connected here. intervene,
Some water-cooled condensers (2) are also provided with a solenoid valve (7) for gas refrigerant control at the refrigerant inlet.

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

Then, the liquefied refrigerant liquid at room temperature and normal pressure is depressurized by the pressure reducing device (3), becomes a low temperature and low pressure refrigerant liquid, and is sent to the condenser (2), and when it passes through the refrigerant pipe in the condenser (2). However, since the heat required for evaporation is absorbed from the surrounding air, the surrounding air is cooled, and this air is forced into the showcase etc. using a blower.

The refrigerant gas at normal temperature and normal pressure that has almost vaporized in the condenser (4) is sent to the accumulator (5), where gas-liquid separation is applied and only the refrigerant gas is sucked into the compressor (1) and compressed. The temperature and pressure are increased.

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 refrigerant inlet of the water-cooled condenser (2) is closed, and the bypass pipe (6) is closed.
By opening the solenoid valve (6a) of the compressor (1),
The high-temperature, high-pressure refrigerant gas discharged from the refrigerant gas 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 gas and liquid. ), and only the refrigerant gas is sucked into the compressor (1).

When defrosting is completed, open the solenoid valve (7) at the refrigerant inlet of the water-cooled condenser (2) and close the solenoid valve (6a) in the bypass pipe (6) to start defrosting operation. Switches to cooling operation.

[Problem that the invention seeks to solve]

In this way, at the start of defrosting operation, the solenoid valve (7) at the refrigerant inlet of the water-cooled condenser (2) is closed, and at the same time the bypass pipe (6) is closed.
), when the solenoid valve (6a) of the compressor (1) is opened, most of the high-temperature, high-pressure refrigerant gas discharged from the compressor (1) will flow toward the bypass pipe, and a portion will flow toward the water-cooled condenser (2). , Since the solenoid valve (7) in the refrigerant intake section is closed, no accumulation occurs in the condenser (2) and all of the refrigerant flows through the bypass pipe (6).
) is discharged in the opposite direction to the solenoid valve (6a). the result,
The amount of high-temperature, high-pressure refrigerant gas passing through the solenoid valve (6a) increases excessively, and the amount of refrigerant liquid that defrosts and liquefies in the evaporator (4) also increases excessively, causing the accumulator ( 5), the limit of the gas-liquid separation capacity 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. The problem was that the device itself became larger.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling the operation of a refrigeration system which can prevent refrigerant liquid from being sucked into the compressor even in a refrigeration system equipped with a small accumulator, which eliminates the disadvantages of the conventional example.

[Means for solving problems]

In order to achieve the above object, 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 with refrigerant piping, and connects the refrigerant outlet side of the compressor to the pressure reducing device. In a refrigeration system in which the refrigerant outlet side of the condenser is connected to the refrigerant outlet side of the condenser through a defrosting bypass pipe with an intervening solenoid valve, and a solenoid valve is provided on the refrigerant inlet side of the water-cooled condenser, the refrigerant inlet side of the condenser The gist of the solenoid valve is that it closes a while after the bypass management solenoid valve opens, and opens at the same time as the bypass conduit solenoid valve closes.

[Effect]

According to the present invention, by opening both the solenoid valve at the refrigerant inlet of the water-cooled condenser and the solenoid valve at the bypass pipe for the initial setting time of the defrosting operation, no air is allowed to flow inside the water-cooled condenser during that time. Since a certain amount of high-temperature, high-pressure refrigerant gas flows in, the amount of liquefaction in the evaporator is prevented from increasing excessively.

Furthermore, by matching the reverse operation, the amount of liquefaction in the evaporator is held down to a constant amount within the capacity limit of the accumulator, while waiting for the end of defrosting, the electromagnetic Switch to cooling operation by opening and closing the valve and the solenoid valve of the bypass pipe.

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 method of the present invention includes a compressor (1) as shown in FIG. 2, a water-cooled condenser (2), a pressure reducing device (3) such as an expansion valve,
A bypass pipe (6) connects the refrigerant outlet side of the compressor (1) and the refrigerant outlet side of the pressure reducing device (3) by sequentially connecting the evaporator (4) and the accumulator (5) to form a refrigeration cycle.
In the circuit provided with the solenoid valve (6a) provided in the circuit, a specific solenoid valve (7) was provided at the refrigerant inlet of the water-cooled condenser (2).

Based on the operation time chart in Figure 1, the solenoid valve (
To explain the action of 7), the hatched time periods in the figure indicate when the solenoid valves (6a) and (7) are open.

During cooling operation, when defrosting is finished, the solenoid valve (7) at the refrigerant inlet of the condenser (2) is opened, and the solenoid valve (6) at the bypass pipe (6) is opened.
A) is for closing, and these are for sending a signal to each solenoid valve according to the time set on a timer, etc., and the operation of the refrigeration system during cooling operation is exactly the same as in the conventional case. The explanation will be omitted.

Next, to explain the defrosting operation, when defrosting starts, the solenoid valve (7) at the refrigerant inlet of the condenser (2) is kept open for a while without sending a close signal according to the settings of the timer, etc. During this period, a signal is sent to the solenoid valve (6a) of the bypass line (6) to close it.

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

On the other hand, the refrigerant gas that passes through the solenoid valve (6a) as a high-temperature, high-pressure refrigerant gas flows into the evaporator (4), radiates heat for defrosting, and becomes liquefied. (5), where it is separated into gas and liquid. Therefore, by setting an appropriate time in consideration of the gas-liquid separation capacity of the accumulator (5) and closing the solenoid valve (7) at the inlet of the water-cooled condenser (2) using a signal, the refrigerant is compressed. machine (1
A water-cooled condenser for the high-temperature, high-pressure refrigerant gas discharged from the
2), and all high temperature, high pressure refrigerant gas passes through the solenoid valve (6a) of the bypass line (6). As a result, the defrosting time is set so that the amount of high-temperature, high-pressure refrigerant gas liquefied in the evaporator (4) becomes a constant amount and falls within the range of the gas-liquid separation capacity of the accumulator (5). , open the solenoid valve (7) at the refrigerant inlet of the water-cooled condenser (2), and close the solenoid valve (6a).

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

〔Effect of the invention〕

As described above, the refrigeration equipment operation control method of the present invention includes:
A refrigeration cycle is constructed by sequentially connecting a compressor, a water-cooled condenser, a pressure reducing device, an evaporator, and an accumulator. In a refrigeration system that is connected by a frost bypass pipe and is equipped with a solenoid valve on the refrigerant inflow side of a water-cooled condenser, the amount of refrigerant liquefied in the evaporator during defrosting operation is constant, and the amount of Since defrosting can be completed within the gas-liquid separation capacity of the accumulator, the inconvenience of the so-called liquid return phenomenon in which 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 a time chart showing an embodiment of the refrigeration system operation control method of the present invention, FIG. 2 is a block 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 pipe line (6a)...Solenoid valve (7)
... Solenoid valve agent, patent attorney Masuo Ohone Figure 1

Claims (1)

[Claims] A refrigeration cycle is constructed by sequentially connecting a compressor, water-cooled condenser, pressure reducing device, evaporator, and accumulator with refrigerant piping, and a solenoid valve is interposed between the refrigerant outlet side of the compressor and the refrigerant outlet side of the pressure reducing device. In a refrigeration system that is connected by a bypass pipe for defrosting, and also has a solenoid valve on the refrigerant inflow side of the water-cooled condenser, the solenoid valve on the refrigerant inflow side of the condenser is connected to the solenoid valve in the bypass pipe. A method for controlling the operation of a refrigeration system, characterized in that the valve is opened and then closed after a while, and the solenoid valve of the bypass pipe is opened at the same time as the solenoid valve is closed.