JP2024007741A - Refrigerant circuit device - Google Patents

Abstract

To suppress the breakage of a compressor even if a cooling load is small.SOLUTION: A refrigerant circuit 10 which is constituted by sequentially connecting an evaporator 11, a compressor 12, a heat radiator 13 and an expansion mechanism 14 by a refrigerant conduit 15 comprises: an oil separator 20 separating oil included in a refrigerant which is compressed by the compressor 12; an oil valve 23 which is arranged in an introduction conduit 21 introducing the separated oil to the compressor 12, and is brought into an open state when the compressor 12 is driven, and brought into a closed state when the compressor 12 is stopped in the drive; and an oil tank 24 storing the oil. The refrigerant circuit also comprises: an oil storage quantity sensor 25 for detecting whether or not an oil storage quantity of the oil stored in the oil tank 24 is smaller than a reference quantity; and a control portion 30 causing a notification portion 40 to perform a notification action issuing a prescribed alarm when a continuation open time of the oil valve 23 in a state that the oil storage quantity is detected to be smaller than the reference quantity by the oil storage quantity sensor 25 reaches a preset reference time or longer.SELECTED DRAWING: Figure 1

Description

The present invention relates to improvements in refrigerant circuit devices.

Conventionally, a refrigerant circuit device applied to a showcase in a store such as a convenience store has a refrigerant circuit in which carbon dioxide, which is a refrigerant, is sealed, and the refrigerant circuit has an evaporator, a compressor, and an evaporator. , a radiator, and an expansion mechanism are sequentially connected through a refrigerant pipe.

An evaporator is a heat exchanger that cools the surrounding air by evaporating a supplied refrigerant. The compressor includes a first compression element that sucks and compresses the refrigerant evaporated by the evaporator, an intermediate heat exchanger that radiates heat from the refrigerant compressed by the first compression element, and a refrigerant that radiates heat by the intermediate heat exchanger. and a second compression element for compressing.

A radiator is a heat exchanger that heats the surrounding air by radiating heat from a refrigerant compressed by a compressor. The expansion mechanism adiabatically expands the refrigerant that has radiated heat in the radiator and sends it to the evaporator.

In the above refrigerant circuit device, in order to recover the oil contained in the refrigerant discharged from the compressor, the oil contained in the refrigerant compressed by the compressor is separated by an oil separator, and the separated oil is introduced into the oil separator. It is passed through a pipe and returned to the compressor (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2013-108735

By the way, in the refrigerant circuit device proposed in Patent Document 1 mentioned above, the compressor and condenser that constitute the refrigerant circuit are arranged in an outdoor unit installed outside the store. Therefore, during periods when the outside air temperature is low, such as winter, the cooling load is also small, making it difficult to continuously drive the compressor for a sufficient period of time. This makes it difficult for the oil separated by the oil separator to return to the compressor, which may result in damage to the compressor.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a refrigerant circuit device that can prevent damage to a compressor even when the cooling load is small.

In order to achieve the above object, a refrigerant circuit device according to the present invention includes an evaporator, a compressor that sucks and compresses the refrigerant evaporated by the evaporator, and a radiator that radiates heat from the refrigerant compressed by the compressor. and an expansion mechanism that adiabatically expands the refrigerant heat radiated by the radiator and supplies the refrigerant to the evaporator, the refrigerant circuit being configured by sequentially connecting the refrigerant through a refrigerant pipe, the refrigerant circuit device comprising: The circuit includes an oil separator that is disposed in a refrigerant pipe line leading from the compressor to the radiator, and that separates oil contained in the refrigerant compressed by the compressor; and an oil separator that separates the oil separated by the oil separator. The oil introduction pipe is disposed in an oil introduction pipe leading to the compressor, and when the compressor is driven, the oil introduction pipe is in an open state allowing the oil to flow, while the compressor is driven. an oil valve that is in a closed state to restrict the oil from flowing through the oil introduction pipe when the oil is stopped; and an oil tank that stores the oil that has passed through the oil introduction pipe; an oil storage amount detection section that detects whether the amount of stored oil is less than a reference amount; and an oil storage amount detection section that detects whether or not the amount of stored oil is less than a reference amount; The present invention is characterized by comprising a control unit that performs a notification operation to issue a predetermined alarm when the continuous open time is equal to or longer than a preset reference time.

Further, in the refrigerant circuit device according to the present invention, the control unit may be arranged such that a continuous open time of the oil valve in a state where the oil storage amount is detected to be less than the reference amount by the oil storage amount detection unit is less than the reference time. The present invention is characterized in that, if the number of times the advance notice time, which is shorter than the reference time or more, exceeds a predetermined reference number, a notification operation is performed to issue a predetermined advance warning.

Further, the present invention is characterized in that, in the refrigerant circuit device, the oil tank constitutes the compressor.

Further, the present invention is characterized in that, in the refrigerant circuit device, the refrigerant circuit includes an oil cooler disposed in the oil introduction pipe and separated by the oil separator to radiate heat from the oil.

Further, the present invention is characterized in that, in the refrigerant circuit device, the refrigerant is carbon dioxide.

According to the present invention, the refrigerant circuit is arranged in a refrigerant pipe line leading from the compressor to the radiator, and is separated by an oil separator that separates oil contained in the refrigerant compressed by the compressor. When the compressor is driven, the oil introduction pipe is in an open state allowing oil to flow, but when the compressor stops driving. In some cases, an oil valve that is closed to restrict the flow of oil through the oil introduction pipe, and an oil tank that stores the oil that has passed through the oil introduction pipe are provided, and the oil storage amount detection unit detects whether or not the oil is in the oil tank. The control unit detects whether or not the amount of stored oil is less than the reference amount, and the control unit determines how long the oil valve continues to be open when the oil storage amount detection unit detects that the amount of oil storage is less than the reference amount. However, when the time exceeds a preset reference time, a notification operation is performed to issue a predetermined alarm, which has the effect of suppressing damage to the compressor even when the cooling load is small. play.

FIG. 1 is a schematic diagram showing a refrigerant circuit device according to an embodiment of the present invention. FIG. 2 is a flowchart showing the contents of the oil level monitoring control process executed by the oil level monitoring control section of the control section shown in FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a refrigerant circuit device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a refrigerant circuit device according to an embodiment of the present invention. The refrigerant circuit device 1 illustrated here is applied to a showcase 2 applied to a store such as a convenience store, for example, to cool the internal atmosphere of a storage 2a to be cooled, and has a refrigerant circuit 10. ing.

The refrigerant circuit 10 is configured by sequentially connecting an evaporator 11, a compressor 12, a radiator 13, and an expansion mechanism 14 through a refrigerant pipe 15, and is filled with a refrigerant such as carbon dioxide. The evaporator 11 is arranged in the storage 2a of the showcase 2. Although not clearly shown in the figure, the evaporator 11 is disposed in an air passage that communicates with a storage chamber in which products are stored in the storage warehouse 2a.

The compressor 12 is installed in an outdoor unit 3 installed outside the store where the showcase 2 is installed. This compressor 12 is driven in response to a command given from a control unit 30, which will be described later. When driven, the compressor 12 compresses the low-temperature, low-pressure refrigerant discharged from the evaporator 11 and discharges it as a high-temperature, high-pressure refrigerant. It is something. Although not clearly shown in the drawings, in this embodiment, the refrigerant discharged from the evaporator 11 is sucked, compressed by the first compression element, and then radiated, and then compressed by the second compression element and discharged. A two-stage compressor is used.

The heat radiator 13 is arranged in the outdoor unit 3 similarly to the compressor 12. The radiator 13 is a heat exchanger that radiates heat from the refrigerant compressed by the compressor 12 by exchanging heat with the surrounding air. The expansion mechanism 14 is configured by, for example, an electronic expansion valve, and is installed in the showcase 2 similarly to the evaporator 11. The expansion mechanism 14 adiabatically expands the refrigerant discharged from the radiator 13 and supplies it to the evaporator 11.

In such a refrigerant circuit 10, high temperature and high pressure refrigerant discharged from the compressor 12 radiates heat in the radiator 13. The refrigerant that has radiated heat in the radiator 13 is adiabatically expanded by the expansion mechanism 14 and supplied to the evaporator 11 . The refrigerant supplied to the evaporator 11 exchanges heat with the internal atmosphere of the housing 2a supplied by a blower fan (not shown), and cools the internal atmosphere of the housing 2a by absorbing heat. The refrigerant that has passed through the evaporator 11 is sucked into the compressor 12.

Such a refrigerant circuit 10 includes an oil separator 20, an oil cooler 22, an oil valve 23, and an oil tank 24 in addition to the above configuration.

The oil separator 20 is arranged in a refrigerant pipe line 15 extending from the compressor 12 to the radiator 13. The oil separator 20 separates oil such as lubricating oil contained in the refrigerant compressed by the compressor 12.

The oil cooler 22 is disposed in an oil introduction pipe 21 that guides oil separated by the oil separator 20 to the compressor 12. The oil cooler 22 is a heat exchanger that cools the oil passing through the oil introduction pipe 21 by exchanging heat with the surrounding air to radiate heat.

The oil valve 23 is constituted by, for example, a solenoid valve, and is disposed between the oil cooler 22 and the compressor 12 in the oil introduction pipe 21. This oil valve 23 opens and closes in response to commands given from the control unit 30, and when it is in the open state, it allows oil to flow through the oil introduction pipe 21, but it is in the closed state. In this case, the flow of oil through the oil introduction pipe 21 is restricted.

The oil tank 24 stores oil sent to the compressor 12 through the oil introduction pipe 21. This oil tank 24 constitutes the compressor 12.

The refrigerant circuit device 1 also includes an oil storage amount sensor 25, a control section 30, and a notification section 40 as its control system. The oil storage amount sensor 25 is an oil storage amount detection section that detects whether the amount of oil stored in the oil tank 24 is less than a predetermined reference amount. The oil storage amount sensor 25 outputs a detection signal to the control unit 30 when it detects that the oil storage amount is less than a reference amount.

The control unit 30 is electrically connected to the compressor 12, the oil valve 23, and the oil storage amount sensor 25, and operates the refrigerant circuit device 1 according to programs and data stored in the storage unit 35, which is also electrically connected. This is to centrally control the system.

The control unit 30 gives an open command to the oil valve 23 when a drive command is given to the compressor 12, and gives a close command to the oil valve 23 when a drive stop command is given to the compressor 12. It gives instructions.

That is, the oil valve 23 is in an open state that allows oil to flow through the oil introduction pipe 21 when the compressor 12 is driven, and the oil valve 23 is in an open state that allows oil to flow through the oil introduction pipe 21 when the compressor 12 is stopped. 21 is in a closed state to restrict the flow of oil.

The control section 30 has an oil level monitoring control section 31 as a feature of this embodiment. This oil level monitoring control section 31 is for implementing oil level monitoring and control processing, which will be described later.

Note that the control unit 30 may be realized by causing a processing device such as a CPU (Central Processing Unit) to execute a program, that is, by software, or may be realized by hardware such as an IC (Integrated Circuit). Alternatively, it may be realized using a combination of software and hardware.

The notification section 40 is electrically connected to the control section 30, and includes display means capable of displaying various types of information, a device that emits a buzzer sound, and the like. This notification section 40 is a notification means that issues a warning or a preliminary warning based on a command given from the control section 30. Note that the advance warning does not correspond to a warning at present, but is intended to make the user aware that there is a high possibility that a warning will be issued in the near future.

FIG. 2 is a flowchart showing the processing contents of the oil level monitoring control process executed by the oil level monitoring control section 31 of the control section 30 shown in FIG. Hereinafter, the operation of the refrigerant circuit device 1 will be explained with reference to FIG. 2.

In the oil level monitoring control process, the oil level monitoring control section 31 waits for input of a detection signal from the oil storage amount sensor 25 (step S101). When a detection signal is input from the oil storage amount sensor 25 (step S101: Yes), the oil level monitoring control unit 31 calculates the continuous open time of the oil valve 23 (step S102). That is, the oil level monitoring control unit 31 calculates the continuous driving time of the compressor 12.

The oil level monitoring control unit 31 that has calculated the continuous open time of the oil valve 23 in this way determines whether the continuous open time is longer than a predetermined reference time (for example, about 10 minutes) (step S103). .

If the continuous open time is less than the reference time (step S103: No), the oil level monitoring control unit 31 determines whether the continuous open time is longer than the advance notice time (for example, about 9 minutes) shorter than the reference time. A judgment is made (step S104).

If the continuous open time is less than the advance notice time (step S104: No), the oil level monitoring control unit 31 returns the procedure and ends the current process without performing the process described later.

On the other hand, if the duration is equal to or greater than the advance notice time (step S104: Yes), the oil level monitoring control unit 31 counts the number of times the continuation time is equal to or greater than the advance notice time (step S105), and the count number is determined in advance. It is determined whether or not the number of times is equal to or greater than a reference number of times (for example, about five times) (step S106).

If the count is less than the reference number (step S106: No), the oil level monitoring control unit 31 returns the procedure and ends the current process without performing the process described later.

If the count is greater than or equal to the reference number of times (step S106: Yes), the oil level monitoring control unit 31 sends an advance warning issuing command to the notification unit 40 (step S107), and then returns the procedure to the current one. Terminates the process.

According to this, the notification section 40 issues a notice warning by emitting a predetermined buzzer sound while displaying the wording of the notice warning and, for example, a yellow color on the display section, so that the store employees etc. can recognize it. Can be done. In other words, the control unit 30 causes the notification unit 40 to perform a notification operation of issuing an advance warning.

By the way, if the continuous opening time is equal to or longer than the reference time in step S103 (step S103: Yes), the oil level monitoring control section 31 sends an alarm issuing command to the notification section 40 (step S108).

According to this, the notification unit 40 issues a warning such as emitting a buzzer sound different from the advance warning while displaying the warning text and, for example, a red color on the display unit, and alerts store employees, etc. It can be recognized. That is, the control unit 30 causes the notification unit 40 to perform a notification operation to issue an alarm.

The oil level monitoring control unit 31 that has sent out the alarm issuing command resets the count counted in step S105 (step S109), and then returns the procedure to end the current process.

As described above, according to the refrigerant circuit device 1 according to the embodiment of the present invention, the oil storage amount sensor 25 detects whether the amount of oil stored in the oil tank 24 is less than the reference amount. However, when the continuous open time of the oil valve 23 in a state in which the oil storage amount sensor 25 detects that the oil storage amount is less than the reference amount is equal to or longer than a preset reference time, the control unit 30 sets a predetermined value. Since the notification operation of issuing a warning is performed, it is possible to prevent the compressor 12 from being damaged even when the cooling load is small, such as in winter, for example.

In particular, even if the continuous open time of the oil valve 23 in a state where the oil storage amount sensor 25 detects that the oil storage amount is less than the reference amount is less than the reference time, the control unit 30 determines that it is longer than the advance notice period that is shorter than the reference time. When the number of times becomes equal to or greater than a predetermined reference number of times, a notification operation is performed to issue a predetermined advance warning, so it is possible to prevent damage to the compressor 12.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various changes can be made.

In the embodiment described above, the operation of issuing a advance warning is performed, but in the present invention, the operation of issuing a advance warning does not need to be performed.

In the embodiment described above, the control unit 30 that constitutes the refrigerant circuit device 1 caused the notification unit 40 to perform the notification operation, but in the present invention, the control unit that constitutes the refrigerant circuit device manages the store etc. Alternatively, a signal to issue a warning or the like may be sent to the management device, and the management device may cause the notification unit to perform the notification operation.

In the embodiment described above, the oil tank 24 constitutes the compressor 12, but in the present invention, the oil tank may be provided independently of the compressor.

DESCRIPTION OF SYMBOLS 1... Refrigerant circuit device, 2... Showcase, 2a... Housing, 3... Outdoor unit, 10... Refrigerant circuit, 11... Evaporator, 12... Compressor, 13... Heat radiator, 14... Expansion mechanism, 15... Refrigerant pipe 20...Oil separator, 21...Oil introduction pipe, 22...Oil cooler, 23...Oil valve, 24...Oil tank, 25...Oil storage amount sensor, 30...Control unit, 40...Notification unit.

Claims (5)

an evaporator, a compressor that sucks and compresses the refrigerant evaporated by the evaporator, a radiator that radiates heat from the refrigerant compressed by the compressor, and adiabatically expands the refrigerant that radiates heat by the radiator to form the evaporator. A refrigerant circuit device comprising a refrigerant circuit configured by sequentially connecting an expansion mechanism for supplying a refrigerant to an expansion mechanism through a refrigerant pipe,
The refrigerant circuit is
an oil separator that is disposed in a refrigerant pipe line from the compressor to the radiator and that separates oil contained in the refrigerant compressed by the compressor;
An opening is disposed in an oil introduction pipe that leads the oil separated by the oil separator to the compressor, and allows the oil to flow through the oil introduction pipe when the compressor is driven. an oil valve that is in a closed state and restricts the oil from flowing through the oil introduction pipe when the compressor is in a closed state;
an oil tank that stores the oil that has passed through the oil introduction pipe;
an oil storage amount detection unit that detects whether the amount of oil stored in the oil tank is less than a reference amount;
a notification operation that issues a predetermined alarm when the continuous open time of the oil valve in a state where the oil storage amount is detected to be less than a reference amount by the oil storage amount detection section is equal to or longer than a preset reference time; A refrigerant circuit device comprising: a control section for performing the following steps. The control unit is configured to control the control unit to provide a warning time shorter than the reference time even if the continuous open time of the oil valve in a state where the oil storage amount is detected to be less than the reference amount by the oil storage amount detection unit is less than the reference time. 2. The refrigerant circuit device according to claim 1, wherein a notification operation is performed to issue a predetermined advance warning when the number of times the above occurs is equal to or greater than a predetermined reference number. The refrigerant circuit device according to claim 1 or 2, wherein the oil tank constitutes the compressor. The refrigerant circuit device according to claim 1 or 2, wherein the refrigerant circuit includes an oil cooler that is disposed in the oil introduction pipe and is separated by the oil separator to radiate heat from the oil. . The refrigerant circuit device according to claim 1 or 2, wherein the refrigerant is carbon dioxide.

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