JPH10281570A - Discharge pressure abnormal rise prevention apparatus for remote condenser type freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge pressure abnormal rise prevention apparatus wherein an abnormal rise of discharge pressure is prevented at the start of a remote condenser freezer. SOLUTION: A bypass circuit 5 is provided, which includes an opening/closing mechanism such as a solenoid opening/closing valve 51 is interposed between a discharge piping 12 and a high pressure liquid refrigerant line in a body unit 1 of a remote condenser type freezer, and the bypass circuit 5 is opened for a short time after starting of the freezer by opening/closing the opening/ closing mechanism. The life of the opening/closing mechanism is prolonged by opening the bypass circuit 5 is opened only when the freezer is started in the state where surrounding air temperature of a condenser unit 2 exceeds a predetermined value or in the case where interruption time of the freezer exceeds a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing an abnormal rise in discharge pressure of a remote condenser type refrigerating apparatus used for a large ice machine, a large refrigerator and the like.

[0002]

2. Description of the Related Art In a conventional general refrigeration system, a high pressure switch for detecting a discharge gas pressure is provided in a discharge pipe as a discharge pressure abnormal rise preventing device, and when a discharge pressure exceeds a predetermined value. Was configured such that the high pressure switch was operated to stop the refrigeration system.

However, like a refrigerating device conventionally used for a large ice machine, a large refrigerator or the like, a remote condenser separated into a main unit containing a compressor and an evaporator and a condenser unit containing a condenser. In the type refrigeration apparatus, when the refrigeration apparatus is started under a condition in which the ambient air temperature of the condenser unit is high, the discharge gas temperature increases and the specific volume thereof increases. Further, in a situation where the gas refrigerant communication pipe is long and installed in a place where it is exposed to high temperatures, not only the degree of cooling of the discharged gas in the gas refrigerant communication pipe is reduced, but also the gas The refrigerant communication pipe temperature becomes higher than the refrigerant temperature, and the refrigerant may be heated by the gas refrigerant communication pipe, so that the refrigerant flow resistance in the gas refrigerant communication pipe increases. Further, under an installation condition such as an installation place where the liquid refrigerant communication pipe is exposed to a high temperature, the liquid refrigerant is vaporized in the liquid refrigerant communication pipe, and the refrigerant flow resistance in the liquid refrigerant communication pipe increases. For this reason, when the ambient air temperature of the capacitor unit is high,
Depending on the installation condition, the high-pressure pressure immediately after the start of the refrigeration system was abnormally high.

Further, if the refrigeration system is stopped for a long time under the condition that the ambient air temperature of the condenser unit is higher than the ambient air temperature of the main unit, the liquid refrigerant stays in the evaporator. For this reason, when the refrigeration apparatus is subsequently started, a large amount of refrigerant accumulated in the evaporator returns to the compressor and is sucked, and a large amount of refrigerant is discharged from the compressor.
Higher pressures could rise even further.

Therefore, when the refrigeration apparatus is started while the ambient air temperature is higher than a predetermined temperature or the refrigeration apparatus has been stopped for a predetermined time or longer, the high / low pressure change after the start is shown in FIG. As shown in the figure, the discharge pressure (high pressure) in the discharge pipe suddenly increased abnormally. Incidentally, the high pressure in the vicinity of the liquid receiver slowly increased without suddenly increasing.

When the discharge pressure rises abnormally as described above, the high-pressure switch provided in the discharge pipe is operated, so that the high-pressure switch is returned to restart the operation. Further, since the high-pressure switch is operated many times, it is necessary to restore the high-pressure switch each time, and the compressor has been repeatedly started and stopped with this operation. However, this operation is troublesome, and there is a possibility that adverse effects such as the operation of the internal protector of the compressor and the activation of the thermal of the electromagnetic switch as a start switch of the compressor may occur. Further, in order to prevent the high pressure switch from operating at the time of starting, the compressor is operated periodically, for example, about once every three hours when the refrigerating apparatus is stopped, and the refrigerant liquid accumulated in the evaporator is discharged to the high pressure side receiver. However, there is a problem in that it is very troublesome to perform this manually, and there is a problem that the control device becomes expensive to automatically perform the control.

Various devices have been conventionally known as high pressure pressure abnormal rise prevention devices other than the provision of the high pressure switch as described above. For example, Japanese Patent Laid-Open No. 58-12964 discloses a bypass circuit that returns high-pressure refrigerant at the outlet of a compressor to the inlet of the compressor. One that opens a bypass circuit is described. JP-A-59-142359 discloses a refrigeration cycle having an injection circuit, in which a refrigerant outlet of a condenser and a refrigerant suction part of a compressor are connected by a bypass circuit provided with an on-off valve, and a discharge pressure Discloses that this bypass circuit is opened when the temperature rises abnormally. Japanese Utility Model Laid-Open Publication No. 63-155959 discloses a bypass circuit that connects a connection pipe between a throttle device and an outdoor heat exchanger and a discharge pipe connected to a compressor, so that when a high pressure exceeds a predetermined value. Discloses a device for opening this bypass circuit.

However, these are related to refrigeration systems in general, not to remote condenser refrigeration systems, and prevent high pressure from rising above a predetermined value during steady-state operation. However, as described above, it does not correspond to an abnormal rise in discharge pressure at the time of starting, which is peculiar to a remote condenser refrigeration system.
As described above, various proposals have been made for preventing an abnormal increase in high-pressure pressure during steady-state operation. However, no proposal has been made yet for a method for preventing an abnormal increase in discharge pressure at the time of startup, which is unique to a remote condenser refrigeration system.

[0009]

As described above, in a remote condenser refrigerating apparatus separated into a main body unit accommodating a compressor, a cooler and the like and a condenser unit accommodating a remote condenser, the air around the remote condenser is not provided. If the refrigeration system is started while the temperature is higher than the predetermined value or the refrigeration system is stopped for a predetermined time or longer, the length of the gas refrigerant communication pipe, the installation status of the gas refrigerant communication pipe, Depending on the installation conditions such as the relationship between the ambient air temperature and the ambient air temperature of the main unit, the discharge pressure may increase abnormally.

The present invention has been made in view of such a problem existing in the prior art, and an object of the present invention is to make the discharge pressure abnormal when starting the remote condenser type refrigeration apparatus. An object of the present invention is to provide a discharge pressure abnormal rise prevention device for preventing the discharge pressure from rising.

[0011]

According to the first aspect of the present invention, there is provided a main unit containing a compressor, an evaporator, an expansion mechanism, etc., and a condenser unit containing a condenser. In the main unit of the remote condenser type refrigeration apparatus separated from the above, a bypass circuit having an opening / closing mechanism interposed between the discharge pipe and the high-pressure liquid refrigerant line is provided. The bypass circuit is opened for a short time.

Further, in the invention described in claim 2, the refrigeration apparatus is started only when the ambient air temperature of the condenser unit is equal to or higher than a predetermined value, or when the refrigeration apparatus is started with the stop time of the refrigeration apparatus equal to or higher than the predetermined value. This is like opening a bypass circuit.

Further, in the invention according to claim 3, the opening / closing mechanism is an electromagnetic on / off valve.

Further, in the invention according to claim 4, the bypass circuit is provided between the discharge pipe and the receiver inlet pipe.

In the invention according to claim 5, the bypass circuit is provided between a discharge pipe and a receiver outlet pipe.

Therefore, the first aspect of the present invention is configured as described above.
In the above described apparatus for preventing abnormal discharge pressure rise of the remote condenser type refrigerating apparatus, the discharge gas at the time of startup hardly flows to the high-pressure side communication pipe, and the bypass circuit provided in the main unit is opened. As a result, most flows into the high-pressure liquid refrigerant line through this short bypass circuit,
Pipe resistance on the compressor discharge side is reduced, and refrigerant circulation from the high-pressure side to the low-pressure side is suppressed by bypassing the discharge gas to the high-pressure liquid line. As a result, the amount of refrigerant sucked into the compressor is reduced. However, the amount of discharge gas discharged from the compressor is reduced, and an increase in discharge pressure at the time of startup is prevented.

As a measure for preventing a rise in the discharge pressure when the refrigeration apparatus is started, a measure to increase the size of the blower for the condenser or the condenser itself can be considered instead of the invention of claim 1. In this case, However, this does not reduce the refrigerant flow resistance of the communication pipe, which is a major factor in the rise of the discharge pressure at startup. Therefore, a remarkable effect of suppressing a rise in the discharge pressure cannot be obtained. In addition to the increase in the size of the blower for the condenser and the size of the condenser itself, the size of the refrigeration system itself increases, the cost increases, the amount of refrigerant charged into the refrigerant circuit increases, and the fan motor increases in size. Problems arise. In contrast, in the case of the first aspect of the present invention, there is no need to increase the size of the condenser or the fan motor for the condenser, so that the size of the refrigeration system does not increase, the amount of refrigerant charged does not need to be increased, and cost is reduced. The rise is also reduced.

According to the second aspect of the present invention, the bypass circuit is opened only when there is a possibility that the discharge pressure is abnormally increased. Since the opening / closing mechanism is not opened, the opening / closing frequency of the opening / closing mechanism is reduced, and the life thereof is prolonged.

According to the third aspect of the present invention, since the opening / closing mechanism is an electromagnetic opening / closing valve, it is versatile and inexpensive. Opening and closing control is easy.

Further, in the apparatus for preventing an abnormal rise in the discharge pressure of the remote condenser type refrigerating apparatus according to the present invention, since the discharge gas is bypassed at the inlet side of the receiver, the liquid from the condenser to the receiver can be obtained. The flow of the refrigerant is hindered, the circulation of the refrigerant from the high pressure side to the low pressure side is suppressed, and as a result, the amount of refrigerant sucked into the compressor decreases, the amount of discharge gas discharged from the compressor decreases, Is prevented from rising.

According to the fifth aspect of the present invention, since the discharge gas is bypassed at the outlet of the receiver, the liquid from the condenser to the receiver can be prevented. Since the inflow of the refrigerant is prevented, and in the expansion mechanism, the liquid refrigerant and the gas refrigerant mix and flow,
The circulation of refrigerant from the high pressure side to the low pressure side is suppressed, and as a result, the amount of refrigerant sucked into the compressor is reduced, the amount of discharge gas discharged from the compressor is reduced, and the rise of discharge pressure at startup is prevented. Is done.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a remote condenser type refrigerating apparatus used for a large ice machine, a large refrigerator or the like will be described in detail with reference to FIGS. I do.

As shown in FIG. 1, a remote condenser type refrigeration system is a main unit 1 usually installed in a building.
And an air-cooled remote condenser unit 2 normally installed outdoors. The units 1 and 2 are connected by a gas refrigerant communication pipe 3 and a liquid refrigerant communication pipe 4.
Therefore, in such a remote condenser type refrigeration apparatus, both communication pipes may be long depending on the installation location of the remote condenser unit, and the gas refrigerant communication pipes may be exposed to high temperatures during the daytime or the like. .

The compressor 11 is housed in the main unit 1, and its discharge pipe 12 is connected to a joint 31 connecting the gas refrigerant communication pipe 3. In addition, the liquid refrigerant communication pipe 4
Between the joint 41 connecting the compressor and the suction side of the compressor 11, a receiver inlet pipe 13, a receiver 14, a high-pressure side passage of the heat exchanger 15 between the liquid refrigerant and the suction gas, and an expansion mechanism. The temperature-sensitive expansion valve 16, the evaporator 17, and the low-pressure side passage of the heat exchanger 15 are sequentially connected. In addition, 16a is the temperature-sensitive expansion valve 1.
6 is a temperature-sensitive cylinder, which is arranged in an evaporator outlet pipe 18 connecting the evaporator 17 and the heat exchanger 15. Also, 1
7a is a blower for the evaporator attached to the evaporator 17, 19
Is a high pressure switch for detecting the high pressure in the discharge pipe 12.

In the main unit 1, a bypass circuit 5 is provided between the discharge pipe 12 and the receiver inlet pipe 13.
The bypass circuit 5 is provided with an electromagnetic opening / closing valve 51 as an opening / closing mechanism, and is opened for a short time of about several seconds when the present refrigeration apparatus is started by a control device (not shown). An air-cooled condenser 21 is housed in the condenser unit 2, and its inlet and outlet are connected to a joint 32 of the gas refrigerant communication pipe 3 and a joint 4 of the liquid refrigerant communication pipe 4, respectively.
2 are connected. Reference numeral 21a denotes a condenser blower attached to the condenser 21.

Next, the operation of the refrigeration apparatus according to the first embodiment will be described. During a normal operation of the refrigeration apparatus, the discharge gas discharged from the compressor 11 is supplied to the condenser 21 through the discharge pipe 12 and the gas refrigerant communication pipe 3, and radiates heat to outside air to be liquefied. The liquefied refrigerant is supplied to the receiver 14 via the liquid refrigerant communication pipe 4 and the receiver inlet pipe 13, heat-exchanges with the suction gas in the heat exchanger 15, is supercooled, and then thermally expanded. The pressure is reduced by the valve 16, vaporized by the evaporator 17, and further heat-exchanges with the high-pressure liquid refrigerant by the heat exchanger 15.
It is overheated and sucked into the compressor 11. The above operation is not different from that of a normal refrigeration system.

If the above-mentioned remote condenser type refrigeration apparatus is stopped for a long time at the time of high outside air temperature, the ambient air temperature of the main unit 1 becomes lower than that of the condenser unit 2. In such a case, the refrigerant in the refrigerant circuit may remain as a liquid refrigerant on the low-pressure side of the evaporator 17 or the heat exchanger 15 on the main unit 1 side. In addition, the connecting pipe may be long and encased in a high-temperature atmosphere on the way, and the connecting pipe itself may be entirely or locally hot. Under such circumstances, when the refrigeration apparatus is started, if the bypass circuit 5 is not provided, the refrigerant flow resistance of the refrigerant pipe from the discharge port of the compressor 11 to the receiver inlet pipe 13 is large. In addition, it is conceivable that a large amount of refrigerant is sucked into the compressor 11 and a large amount of refrigerant is discharged from the compressor 11, so that the discharge pressure is abnormally increased.

However, in the present embodiment, when the refrigerating apparatus is started, the electromagnetic opening / closing valve 51 as an opening / closing mechanism interposed in the bypass circuit 5 is opened for a short time of about several seconds by a control device (not shown). . For this reason, the compressor 11
Is discharged through the bypass circuit 5 having a small refrigerant flow resistance to form a narrow space in the receiver inlet pipe 13.
Therefore, the flow of the refrigerant from the condenser 21 is suppressed, the amount of the refrigerant flowing from the high pressure side to the low pressure side is reduced, the amount of the refrigerant sucked into the compressor 11 is reduced, and the discharge of the compressor 11 is reduced. The rise in pressure is suppressed. FIG. 2 shows transient changes in the high pressure and the low pressure at this time. Thus, in the present embodiment, an increase in the discharge pressure is suppressed without increasing the size of the condenser 21 or the condenser blower 21a.

Next, a second embodiment will be described with reference to FIG. The second embodiment differs from the first embodiment in the configuration of the bypass circuit.
Others are the same. That is, in the present embodiment,
The bypass circuit 5A is formed between the discharge pipe 12 of the compressor 11 and the receiver outlet pipe 13A, and the bypass circuit 5A is provided with an electromagnetic on-off valve 51. Also,
Opening / closing control of the electromagnetic on-off valve 51 is performed in the same manner as in the first embodiment.

Therefore, in the case of the second embodiment, when the refrigerating apparatus is started, the electromagnetic on-off valve 51 is opened for a short time as described above, so that the discharge gas discharged from the compressor 11 is supplied to the bypass circuit. It is bypassed to the receiver outlet pipe 13A which is a narrow space through 5A. For this reason, the flow of the refrigerant from the liquid receiver 14 to the temperature-sensitive expansion valve 16 is hindered, and since the gas refrigerant and the liquid refrigerant flow in the temperature-sensitive expansion valve 16 in a mixed state, the pressure from the high pressure side to the low pressure side is reduced. The flow of the refrigerant is suppressed, and as a result, the amount of gas sucked into the compressor 11 is reduced, and an increase in high-pressure pressure when the compressor is started is prevented. Thus, the second book
Also in this embodiment, an increase in the discharge pressure is suppressed without increasing the size of the condenser 21 or the condenser blower 21a.

Although the two embodiments have been described above,
The present invention can be embodied with the following modifications. (1) The junction of the bypass circuit may be any location as long as it is between the high-pressure liquid line in the unit 1, that is, from the joint 41 to the inlet side of the thermal expansion valve 16. For example,
This junction may be used as a pipe connecting the heat exchanger 15 and the temperature-sensitive expansion valve 16. In addition, it is not preferable that the junction is on the low pressure side because the high pressure and the low pressure are too low.

(2) The electromagnetic on-off valve 51 interposed in the bypass circuits 5 and 5A is not always opened when the refrigerating apparatus is started, but the ambient air temperature of the condenser unit is higher than a predetermined value, or The bypass circuits 5, 5A are opened only when the operation is started with the stop time being equal to or longer than a predetermined value. With this configuration, the electromagnetic on-off valve 51 may be opened and closed only when it is necessary to suppress an abnormal increase in the discharge pressure.
The opening / closing frequency can be reduced, and the life of the solenoid on-off valve 51 can be extended.

(3) As an opening / closing mechanism for the bypass circuits 5, 5A, the electromagnetic on / off valve 51 is eliminated, and a three-way switching valve is provided at a branch point or a junction of the bypass circuit. To open.

[0034]

Since the present invention is configured as described above, the following effects can be obtained. According to the first aspect of the present invention, the piping resistance on the compressor discharge side at the time of starting the refrigeration system is reduced, and an increase in discharge pressure is prevented. Further, since the size of the condenser and the blower for the condenser is not increased, the size of the device and the amount of refrigerant charged are not increased, and the cost is reduced.

According to the second aspect of the present invention, the discharge pressure abnormal rise preventing device operates only when there is a possibility that the discharge pressure may abnormally increase, and does not operate in a normal state. And its lifespan is prolonged.

According to the third aspect of the present invention, since the opening / closing mechanism is an electromagnetic opening / closing valve, it is versatile, inexpensive, and its opening / closing control is easy.

According to the fourth and fifth aspects of the present invention, since the discharge gas is bypassed to the pipe, which is a narrow space of the high pressure liquid line, the flow of the refrigerant from the high pressure side to the low pressure side is efficiently prevented. As a result, the amount of refrigerant sucked into the compressor decreases, the amount of discharge gas discharged from the compressor decreases, and an increase in discharge pressure at the time of startup can be efficiently prevented. .

In particular, in the case of the invention described in claim 5, since the resistance in the expansion mechanism is increased, the flow of the refrigerant from the high pressure side to the low pressure side is more efficiently prevented, and the discharge pressure at the time of startup is reduced. Ascent is prevented.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a remote condenser refrigeration apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing changes in high pressure and low pressure when the refrigeration apparatus of FIG. 1 is started.

FIG. 3 is a refrigerant circuit diagram of a remote condenser refrigeration apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram showing changes in high pressure and low pressure when a conventional remote condenser refrigeration apparatus is started.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... This unit, 2 ... Condenser unit, 3 ... Gas refrigerant communication pipe, 4 ... Liquid refrigerant communication pipe, 5 and 5A ... Bypass circuit, 11 ... Compressor, 12 ... Discharge pipe, 13 ... Liquid receiver inlet pipe, 13A ... Receiver outlet piping, 14 ... Receiver, 15
... heat exchanger, 16 ... temperature-sensitive expansion valve as expansion mechanism, 17
... Evaporator, 21 ... Condenser, 51 ... Electromagnetic on / off valve as opening / closing mechanism.

Claims (5)

[Claims] 1. A discharge pipe and a high-pressure liquid in a main unit of a remote condenser type refrigerating apparatus separated into a main unit containing a compressor, an evaporator, an expansion mechanism and the like, and a condenser unit containing a condenser. A remote condenser type refrigerating apparatus characterized in that a bypass circuit having an opening / closing mechanism interposed between the refrigerant line and the opening / closing mechanism is provided to open the bypass circuit for a short time after the start of the refrigerating apparatus. Discharge pressure abnormal rise prevention device. 2. The method according to claim 1, wherein the bypass circuit is opened only when the ambient temperature of the condenser unit is equal to or higher than a predetermined value or when the refrigeration apparatus is started while the stop time of the refrigeration apparatus is equal to or higher than the predetermined value. The apparatus for preventing abnormal rise in discharge pressure of a remote condenser type refrigeration apparatus according to claim 1, wherein: 3. The apparatus according to claim 1, wherein said opening / closing mechanism is an electromagnetic on / off valve. 4. An abnormal rise in discharge pressure of a remote condenser refrigeration system according to claim 1, wherein said bypass circuit is provided between a discharge pipe and a receiver inlet pipe. Prevention device. 5. An abnormal rise in discharge pressure of a remote condenser refrigeration system according to claim 1, wherein said bypass circuit is provided between a discharge pipe and a receiver outlet pipe. Prevention device.