JP2022066863A - Oil amount adjustment device, oil amount adjustment method, oil amount adjustment program, and refrigeration system - Google Patents

Abstract

To provide an oil amount adjustment device which supplies a refrigeration machine oil to an oil container according to a detection result, by detecting oil level height of the refrigeration machine oil in the oil container at three stages, to provide a refrigeration system, an oil amount adjustment method, and an oil amount adjustment program.SOLUTION: An oil amount adjustment device 200 is applied to a system including a plurality of compressors 11, 12, and a plurality of oil containers 13a, 13b provided corresponding to each compressor. The oil amount adjustment device 200 includes: first detection parts OLS-1a, OLS-2a provided at the oil containers 13a, 13b; second detection parts OLS-1b, OLS-2b provided below the first detection parts OLS-1a, OLS-2a; third detection parts OLS-1c, OLS-2c provided below the second detection parts OLS-1b, OLS-2b; and a control part 50 for performing oil amount adjustment of the oil containers 13a, 13b based on the detection result of each detection part.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to an oil amount adjusting device, an oil amount adjusting method, an oil amount adjusting program, and a freezing system.

For example, a cooling / heating facility installed in a store or the like has a condensing unit as an outdoor unit in which a compressor, a condenser, or the like is mounted on the same frame to form a unit.
Evaporator units (unit coolers, showcase coolers, etc.) combined with condensin units vary widely according to individual requirements such as the number and shape of the evaporator units.
For example, due to changes in the number of evaporator units and the length of connecting pipes, refrigerating machine oil (lubricating oil) may stay in the evaporator units and connecting pipes, causing a drop in the oil level in the compressor. .. In addition, there was a possibility that the compressor would malfunction due to lack of oil.

Patent Document 1 describes the oil level height in a tank by installing two sensors at different heights on the tank in a compressor connected to a tank that stores oil by two pipes having different heights. Is disclosed to detect and adjust the oil level inside the compressor. Of the above two sensors, the sensor installed at the higher position detects that the refrigerating machine oil in the tank is decreasing, and the sensor installed at the lower position determines that the amount of refrigerating machine oil in the tank is the refrigerant circuit. It detects that the amount required for normal operation is insufficient.

Further, a technique has been proposed in which the amount of oil is increased by controlling the supply of oil into the tank when it is detected that the amount of oil has decreased. For example, Patent Document 2 discloses an oil leveling control that equalizes an unbalanced amount of oil by changing the rotation speeds of a plurality of compressors.

Japanese Unexamined Patent Publication No. 2016-118317 JP-A-2018-109452

However, for example, oil leveling control for equalizing the amount of oil by changing the rotation speed of the compressor as described in Patent Document 2 causes an overload on the compressor if it is performed frequently, resulting in failure or failure. It may cause performance degradation.

The present disclosure has been made in view of such circumstances, and is an oil amount adjusting device, an oil amount adjusting method, and an oil amount that reduce the load on the compressor and suppress the frequency of abnormal stoppage of the compressor. It is intended to provide a conditioning program as well as a refrigeration system.

The oil amount adjusting device according to the first aspect of the present disclosure includes a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. It is an oil amount adjusting device applied to the system provided with, and is provided in each oil container, and detects that the oil level of the oil container is lower than the first oil level which is a reference of oil leveling control. In the first detection unit and each of the oil containers, it is detected that the oil level of the oil container is below the second oil level, which is provided below the first detection unit and serves as a reference for oil return control. The second detection unit and each of the oil containers are provided below the second detection unit, and detect that the oil level of the oil container is below the third oil level, which is a reference for abnormality detection. A third detection unit is provided, and a control unit that adjusts the amount of oil in the oil container based on the detection results of the first detection unit, the second detection unit, and the third detection unit.

The oil amount adjusting method according to the second aspect of the present disclosure includes a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. A step of detecting that the oil level of the oil container is lower than the first oil level, which is a reference for oil leveling control, in each of the oil containers. In each of the oil containers, a step of detecting that the oil level of the oil container is below the second oil level which is a reference for oil return control, and in each of the oil containers, the oil level of the oil container is It includes a step of detecting that the oil level is below the third oil level, which is a reference for detecting an abnormality, and a step of adjusting the amount of oil in the oil container based on the detection result of each of the steps.

The oil amount adjustment program according to the third aspect of the present disclosure includes a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. It is an oil amount adjustment program applied to a system comprising, and is a process of detecting that the oil level of the oil container is lower than the first oil level which is a standard for oil leveling control in each of the oil containers. In each of the oil containers, a process of detecting that the oil level of the oil container is below the second oil level which is a reference for oil return control, and in each of the oil containers, the oil level of the oil container is A computer is made to execute a process of detecting that the oil level is below the third oil level, which is a reference for detecting an abnormality, and a process of adjusting the amount of oil in the oil container based on the detection result of each of the steps.

According to the present disclosure, it is possible to reduce the load on the compressor and suppress the frequency of abnormal stoppage of the compressor.

It is a figure which shows the schematic structure of the refrigeration system which concerns on one Embodiment of this disclosure. It is a figure which showed an example of the hardware composition of the control device which concerns on one Embodiment of this disclosure. It is a schematic diagram about the structure of the oil amount adjusting device which concerns on one Embodiment of this disclosure, and the peripheral structure thereof. It is a time chart which shows the rotation speed and time of each compressor in the oil leveling control which concerns on one Embodiment of this disclosure. It is a flowchart which showed an example of the procedure of the oil amount adjustment control processing which concerns on one Embodiment of this disclosure. It is a flowchart which showed an example of the procedure of the oil amount adjustment control processing which concerns on one Embodiment of this disclosure. It is a figure which shows the schematic structure of the refrigerating system provided with the oil leveling pipe which concerns on other aspects of this disclosure.

Hereinafter, the oil amount adjusting device, the oil amount adjusting method, the oil amount adjusting program, and the refrigerating system according to the embodiment of the present disclosure will be described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a refrigerant circuit of a refrigerating system 300 according to an embodiment of the present disclosure.
As shown in FIG. 1, the refrigerating system 300 includes a refrigerant circuit including compressors 11 and 12, gas coolers (condensers) 16a and 16b, expansion valve SC-V1, heat exchanger (evaporator) 80, and a control device. It has 100 as the main configuration. The heat exchanger (evaporator) 80 is provided in the showcase 2. Further, a gas-liquid separator such as an accumulator 14, oil separators 15a and 15b is connected to the refrigerant circuit. Further, an oil container 13a is connected to the compressor 11, and an oil container 13b is connected to the compressor 12.
Each of the above configurations is connected by a refrigerant pipe, an oil pipe, or the like.

The compressors 11 and 12 compress the refrigerant and supply the compressed high-pressure refrigerant to the refrigerant circuit. In the present embodiment, the compressor 11 is a two-stage compressor composed of a first-stage first-stage compression unit 11a and a second-stage second-stage compression unit 11b. Similarly, the compressor 12 is a two-stage compressor composed of a first-stage first-stage compression unit 12a and a second-stage second-stage compression unit 12b. In the refrigeration system 300, the compressor 11 and the compressor 12 are provided in parallel. Further, as will be described later, the compressor 11 is connected to the oil container 13a via the communication pipes CP1 and CP2, respectively, and similarly, the compressor 12 is connected to the oil container 13b via the communication pipes CP3 and CP4, respectively.
For example, CO2 is used as the refrigerant of the present embodiment. The CO2 refrigerant has a large pressure difference between high pressure and low pressure, and a two-stage compression structure is adopted to improve compressor efficiency. Further, in order to improve performance and efficiency, a gas injection mechanism for supplying an intermediate pressure (medium pressure) refrigerant to the second stage compression portions 11b and 12b of the compressors 11 and 12 is adopted.

The upper part of the oil container 13a and the discharge side of the first stage compression portion 11a of the compressor 11 are communicated with each other by a communication pipe CP1. Apart from the refrigerating machine oil flowing from the oil return pipe RP11, during the operation of the compressor 11, the refrigerating machine oil also flows into the oil container 13a from the communication pipe CP1 communicating with the discharge side of the first stage compression unit 11a. Further, the bottom of the oil container 13a communicates with the bottom of the compressor 11 by the communication pipe CP2. The refrigerating machine oil accumulated under the oil container 13a is returned to the compressor 11 through the communication pipe CP2 at the bottom.

Further, in the oil container 13a, a first detection unit OLS-1a, a second detection unit OLS-1b, and a third detection unit OLS-1c are provided in order to detect the oil level height in the oil container 13a step by step. They are installed at different heights.

The first detection unit OLS-1a that detects the oil level height in the oil container 13a detects that the oil level of the oil container 13a is lower than the first oil level that is a standard for oil leveling control described later. do. Then, when the oil level of the oil container 13a is equal to or higher than the first oil level, an ON signal is output, and when the oil level of the oil container 13a is lower than the first oil level, the oil container 13a A signal (off signal) indicating a drop in the oil level is output to the control device 100.
Here, the oil leveling control is a control for adjusting each oil amount and eliminating the oil amount imbalance when an imbalance occurs in the amount of oil stored in the oil container 13a and the oil container 13b, respectively.

The second detection unit OLS-1b is provided below the first detection unit OLS-1a, and the oil level of the oil container 13a is lower than the second oil level which is a reference for oil return control described later. Is detected. Then, when the oil level of the oil container 13a is equal to or higher than the second oil level, an ON signal is output, and when the oil level of the oil container 13a is lower than the second oil level, the oil container 13a A signal (off signal) indicating a drop in the oil level is output to the control device 100.
Here, the oil return control is a control in which the refrigerating machine oil circulating inside the refrigerating system 300 is recovered in the accumulator 14, and the recovered refrigerating machine oil is returned to the compressor 11 and the compressor 12.

The third detection unit OLS-1c is provided below the second detection unit OLS-1b, and detects that the oil level of the oil container 13a is below the third oil level, which is a reference for abnormality detection. When the oil level of the oil container 13a is equal to or higher than the third oil level, for example, an on signal is output, and when the oil level of the oil container 13a is lower than the third oil level, the oil container is output. A signal (off signal) indicating a drop in the oil level of 13a is output to the control device 100.

Similarly, for the oil container 13b on the compressor 12 side, the upper part of the oil container 13b and the discharge side of the first stage compression portion 12a of the compressor 12 are communicated with each other by a communication pipe CP3. Apart from the refrigerating machine oil flowing in from the oil return pipe RP12, the refrigerating machine oil also flows into the oil container 13b from the communication pipe CP3 communicating with the discharge side of the first stage compression unit 12a during the operation of the compressor 12. Further, the bottom of the oil container 13b communicates with the bottom of the compressor 12 by a communication pipe CP4. The refrigerating machine oil accumulated under the oil container 13b is returned to the compressor 12 through the communication pipe CP4 at the bottom.
Further, in the oil container 13b, the first detection unit OLS-2a, the first detection unit OLS-2a, like the first detection unit OLS-1a, the second detection unit OLS-1b, and the third detection unit OLS-1c provided in the oil container 13a. 2 The detection unit OLS-2b and the third detection unit OLS-2c are provided.

The accumulator 14 separates the gas and liquid of the refrigerant supplied to the compressors 11 and 12. The gas refrigerant separated by the accumulator 14 passes through the accumulator 21 attached to the compressor 11 and the accumulator 21 attached to the compressor 11 and is supplied to the accumulator 22 attached to the compressor 12. The gas refrigerant from which only the gas phase has been further extracted by the accumulator 21 is supplied to the suction side of the first-stage compression unit 11a of the compressor 11. Similarly, the gas refrigerant from which only the gas phase has been further extracted by the accumulator 22 is supplied to the suction side of the first stage compression unit 12a of the compressor 12.
Further, in the oil leveling control and the oil return control, the refrigerating machine oil contained in the refrigerant recovered in the accumulator 14 is transferred to the compressor 11 via the suction pipe MP14 and similarly to the compressor 12 via the suction pipe MP15. Each is supplied. As a result, the oil levels of the oil containers 13a and 13b can be raised.

The refrigerant discharged from the compressor 11 is supplied to the oil separator 15a via the discharge pipe MP01 on the discharge side. In the oil separator 15a, the refrigerant and the refrigerating machine oil dissolved in the refrigerant are separated, and the refrigerant flows to the gas pipe MP10 and the hot gas bypass pipe BP11.

One of the hot gas bypass pipe BP11 is connected to the gas pipe MP10 between the oil separator 15a and the check valve CV1. The flow of the refrigerant in the hot gas bypass pipe BP11 is controlled by opening and closing the valve HG-V1. That is, when the control device 100 opens the valve HG-V1, the refrigerant discharge side of the oil separator 15a and the suction side of the accumulator 14 communicate with each other, and the refrigerant flows through the hot gas bypass pipe BP11.
During the operation of the refrigeration system 300, the valve HG-V1 is fully closed. As a result, the refrigerant flows through the gas pipe MP10 without flowing through the hot gas bypass pipe BP11.

In the oil separator 15a, the refrigerant and the refrigerating machine oil dissolved in the refrigerant are separated, and the refrigerant flows to the gas pipe MP10 via the check valve CV1. Further, the bottom of the oil separator 15a and the side surface of the oil container 13a communicate with each other by an oil return pipe RP11. The refrigerating machine oil separated by the oil separator 15a is returned to the oil container 13a via the oil return pipe RP11.

The oil return pipe RP11 is divided into two flow paths. A valve R-V1 is provided in the piping of one of the flow paths. The amount of refrigerating machine oil returned to the oil container 13b is adjusted by opening and closing the valve RV1.

Similar to the compressor 11 side, the refrigerant discharged from the compressor 12 is supplied to the oil separator 15b via the discharge pipe MP02 on the discharge side. In the oil separator 15b, the refrigerant and the refrigerating machine oil dissolved in the refrigerant are separated, and the refrigerant flows to the gas pipe MP10 and the hot gas bypass pipe BP12.

One of the hot gas bypass pipes BP12 is connected to the gas pipe MP10 between the oil separator 15b and the check valve CV2. The flow of the refrigerant in the hot gas bypass pipe BP12 is controlled by opening and closing the valve HG-V2. That is, when the control device 100 opens the valve HG-V2, the refrigerant discharge side of the oil separator 15b and the suction side of the accumulator 14 communicate with each other, and the refrigerant flows through the hot gas bypass pipe BP12.
During the operation of the refrigeration system 300, the valve HG-V2 is fully closed. As a result, the refrigerant flows through the gas pipe MP10 without flowing through the hot gas bypass pipe BP12.

Similar to the compressor 11 side, in the oil separator 15b, the refrigerant and the refrigerating machine oil dissolved in the refrigerant are separated, and the refrigerant flows to the gas pipe MP10 via the check valve CV2. Further, the bottom of the oil separator 15b and the side surface of the oil container 13b communicate with each other by an oil return pipe RP12. The refrigerating machine oil separated by the oil separator 15b is returned to the oil container 13b via the oil return pipe RP12.
The oil return pipe RP11 is divided into two flow paths. A valve R-V2 is provided in the piping of one of the flow paths. The amount of refrigerating machine oil returned to the oil container 13b is adjusted by opening and closing the valve RV2.

The high-temperature and high-pressure refrigerant discharged by the compressors 11 and 12 is supplied to the gas coolers 16a and 16b provided in parallel via the gas pipe MP10. The refrigerant supplied to the gas coolers 16a and 16b is condensed by heat exchange with the air sent by the fans 17a and 17b. In the case of CO2 refrigerant, it is cooled.

The refrigerant cooled or condensed by the gas coolers 16a and 16b is sent to the heat exchanger 80 provided in the showcase 2 via the gas-liquid two-phase pipe MP11 and the liquid pipe MP12. At this time, the refrigerant is depressurized by the valve SC-V1 provided in the liquid pipe MP12 and then sent to the heat exchanger 80. In the heat exchanger 80, the refrigerant that has been heated by heat exchange between the refrigerant and the target medium (for example, air or water) is output to the pipe IP10.

The pipe IP10 branches into the pipe IP11 and the pipe IP12, and the refrigerant is sent to the compressor 11 through the pipe IP11 and also to the compressor 12 through the IP12. Further, the liquid phase refrigerant in the heat exchanger 80 is supplied to the accumulator 14 through the return pipe MP13.

The control device 100 controls the refrigeration system 300 according to the present disclosure. Specifically, the compressors 11 and 12, the gas coolers 16a and 16b, the fans 17a and 17b, and the valves and the like are controlled. Further, the control device 100 includes an oil amount adjustment control unit 50. The oil amount adjustment control unit 50 is a detection result input from the first detection unit OLS-1a and OLS-2a, the second detection unit OLS-1b and OLS-2b, and the third detection unit OLS-1c and OLS-2c. The amount of oil in the oil containers 13a and 13b is adjusted based on the on signal and the off signal).

FIG. 2 is a diagram showing an example of the hardware configuration of the control device 100 according to the embodiment of the present disclosure.
As shown in FIG. 2, the control device 100 is a computer system (computer system), for example, a CPU 51, a ROM (Read Only Memory) 52 for storing a program or the like executed by the CPU 51, and when each program is executed. It is provided with a RAM (Random Access Memory) 53 that functions as a work area, a hard disk drive (HDD) 54 as a large-capacity storage device, and a communication unit 55 for connecting to a network or the like. As the large-capacity storage device, another storage device such as a solid state drive (SSD) may be used. Each of these parts is connected via a bus 58.

Further, the control device 100 may include an input unit including a keyboard, a mouse, and the like, a display unit including a liquid crystal display device for displaying data, and the like.

Next, the oil amount adjusting device 200 according to the present embodiment will be described with reference to FIG. FIG. 3 is a schematic diagram of the configuration of the oil amount adjusting device 200 and its peripheral configuration. As shown in FIG. 3, in the oil amount adjusting device 200 according to the present embodiment, the first detection units OLS-1a and OLS-2a, the second detection units OLS-1b and OLS- provided in the oil containers 13a and 13b. 2b, a third detection unit OLS-1c and OLS-2c, and an oil amount adjustment control unit 50 are provided.
A series of processing processes realized by the oil amount adjustment control unit 50, which will be described later, is recorded in a hard disk drive 54 or the like included in the control device 100 in the form of a program (for example, an oil amount adjustment program), and this program is recorded in the CPU 51. Reads into a RAM 53 or the like and executes information processing / arithmetic processing, thereby realizing various functions described later. The program is installed in the ROM 52 or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.
In this embodiment, the case where the oil amount adjustment control unit 50 is incorporated in the control device 100 will be described as an example, but the present invention is not limited to this example. For example, the oil amount adjustment control unit 50 may be provided separately from the control device 100, and may be configured to exchange information between the control device 100 and the oil amount adjustment control unit 50.

Hereinafter, various controls performed by the oil amount adjustment control unit 50 will be described.

[Operation of oil leveling control]
In the oil amount adjustment control unit 50, for example, the detection result of the first detection unit OLS-1a of the oil container 13a and the first detection unit OLS-2a of the oil container 13b is at least one of the oil levels of the oil containers 13a and 13b. The oil leveling control is executed when it is detected that is below the first oil level which is the reference for the oil leveling control. As illustrated in FIG. 3, the oil amount adjustment control unit 50 is detected by the first detection unit OLS-1a to be below the first oil level, and is detected by the first detection unit OLS-2a. 1 When it is not detected that the oil level is below the oil level, the rotation speed of the compressor 11 is increased and the rotation speed of the compressor 12 is decreased. As a result, the pressure of the compressor 11 decreases, and the amount of oil sucked by the compressor 11 from the accumulator 14 becomes larger than in the normal operation. On the contrary, the pressure of the compressor 12 increases, and the amount of oil sucked from the accumulator 14 by the compressor 12 becomes smaller than in the normal operation. In this way, by changing the rotation speeds of the compressors 11 and 12 and continuing the oil leveling control for a predetermined time, the difference in the amount of oil between the oil container 13a and the oil container 13b is reduced. Then, the oil leveling control is terminated by the oil amount adjustment control unit 50 after a predetermined time has elapsed. When it is detected by the first detection units OLS-1a and OLS-2a that the oil levels of the oil containers 13a and 13b are above the first oil level, respectively, the oil level adjustment control unit 50 controls the oil leveling. May be terminated. Further, the oil amount adjustment control unit 50 detects that the oil level is below the first oil level by the first detection unit OLS-2a, and is detected by the first detection unit OLS-1a that the oil level is below the first oil level. If not, the rotation speed of the compressor 12 is increased and the rotation speed of the compressor 11 is decreased.
Further, in the present embodiment, after the oil leveling control is performed, the next oil leveling control is not performed until a predetermined time elapses.

[Time chart of compressor rotation speed change in oil leveling control]
FIG. 4 is a time chart showing the rotation speeds and times of the compressors 11 and 12 in the oil leveling control. As an example, FIG. 4 shows the compressor 11 in the case where the oil level of the oil container 13a is below the first oil level and the oil level of the oil container 13b is above the first oil level, as shown in FIG. , 12 is a diagram showing an example of rotation speed control.

(Time t0 to t1)
First, when the oil leveling control is not performed, the oil amount adjustment control unit 50 drives the compressors 11 and 12 at a rotation speed according to the load.

(Time t1)
Next, when it is detected by the first detection unit OLS-1a or OLS-2a at time t1 that the oil level of the oil container 13a or the oil level of the oil container 13b is lower than the first oil level, the amount of oil Oil leveling control is executed by the adjustment control unit 50.

(Time t2 to t5)
Next, between the times t2 and t5, the rotation speeds of the compressors 11 and 12 are stepped by the oil amount adjustment control unit 50 at predetermined time intervals from the oil leveling control step 1 to the oil leveling control step 3. Will be changed. Specifically, the rotation speed of the compressor 11 is gradually increased, and the rotation speed of the compressor 12 is gradually decreased.

(After time t5)
Then, when the oil leveling control step 3 is performed for a predetermined period, it is considered that the oil amount has been made uniform, the oil leveling control is terminated, and the normal control is returned. Not limited to this example, for example, during oil leveling control, the oil levels of the oil container 13a and the oil container 13b are above the first oil level by the first detection units OLS-1a and OLS-2a. When it is detected, the oil leveling control may be terminated.

[Oil return control operation]
When the second detection unit OLS-1b or OLS-2b detects that the oil level of the oil container 13a or the oil level of the oil container 13b is below the second oil level, the oil amount adjustment control unit 50 detects it. Oil return control is executed.
In the oil return control, when the oil amount adjustment control unit 50 detects, for example, that the second detection unit OLS-1b or OLS-2b is below the second oil level, the compressor 11 and the compressor 12 rotate. Increase the number. As a result, the pressures of the compressors 11 and 12 decrease, and the amount of oil sucked by the compressors 11 and 12 from the accumulator 14 becomes larger than that during normal operation. In this way, by increasing the rotation speeds of the compressors 11 and 12 and continuing the operation for a predetermined time, the amount of oil in the oil containers 13a and 13b increases. Then, when the oil return control is continuously performed for a predetermined time, it is considered that the refrigerating machine oil has sufficiently returned to the oil container 13a and the oil container 13b, and the oil return control is terminated.
Further, in the oil return control, for example, during the oil return control, the second detection units OLS-1b and OLS-2b detect that the oil levels of the oil container 13a and the oil container 13b are equal to or higher than the second oil level. If it is done, it may be terminated. Further, the rotation speed control of the compressors 11 and 12 in the oil return control may be changed stepwise in the same manner as the oil leveling control.

[Abnormal stop operation]
When the oil level of the oil container 13a or the oil level of the oil container 13b is detected by the third detection unit OLS-1c or OLS-2c to be lower than the third oil level, the oil amount adjustment control unit 50 detects it. Abnormal stop due to lack of oil is executed.

〔flowchart〕
Next, an example of the oil amount adjustment control process of the oil containers 13a and 13b executed by the oil amount adjustment control unit 50 will be described. 5 to 6 are flowcharts showing an example of the procedure of the oil amount adjustment control process according to the present embodiment. The following oil amount adjustment control process is started, for example, at the time of starting the refrigerating system 300.

First, when the refrigeration system 300 is activated (S101), it is determined whether or not the compressors 11 and 12 are operating (S102). As a result, when both the compressors 11 and 12 are not operating (S103: NO), the process of step S102 is repeated until the compressors 11 and 12 start operation.

Further, when at least one of the compressors 11 and 12 is operating (S102: YES), subsequent control is performed on the operating compressor. In the following description, the case where both the compressors 11 and 12 are operating is illustrated, but when one of the compressors is stopped, the operating compressor is used. The following processing is performed on the target.
First, whether or not any of the first detection units OLS-1a and OLS-2a is off, that is, whether or not the oil level height of either the oil container 13a or 13b is lower than the first oil level. Is determined (S103). As a result, when neither of the first detection units OLS-1a and OLS-2a is off (S103: NO), that is, when both the oil levels of the oil containers 13a and 13b are above the first oil level, The process returns to step S102 and the subsequent processing is performed.

When the oil container 13a or 13b is off (S103: YES), it is determined whether or not any of the second detection units OLS-1b and OLS-2b is off (S104). As a result, when neither of the second detection units is off, that is, when neither the oil level of the oil containers 13a and 13b is below the second oil level (S104: NO), the previous oil leveling control execution is executed. It is determined whether the elapsed time from time is equal to or longer than a preset predetermined time (S105). As a result, when the elapsed time from the previous execution of the oil leveling control is equal to or longer than a predetermined time (S105: YES), the oil leveling control is executed (S106). As a result, the rotation speeds of the compressors 11 and 12 are changed based on the detection results of the first detection units OLS-1a and OLS-2a, and the imbalance between the oil levels of the oil containers 13a and 13b is reduced.

Subsequently, it is determined whether or not a predetermined period has elapsed since the execution of the oil leveling control (S107). As a result, if the predetermined time has not elapsed (S107: NO), the oil leveling control is continuously performed until the predetermined period elapses. Then, when the oil leveling control is executed for a predetermined period (S107: YES), the process returns to step S102 and the subsequent processing is performed.

On the other hand, when it is determined in step S104 that any of the second detection units is off (S104: YES), or in step S105, the elapsed time from the previous execution of the oil leveling control is less than a predetermined time. In (S105: NO), it is determined whether or not the third detection unit OLS-1c and OLS-2c are off (S108 in FIG. 6). As a result, when none of the third detection units is off, that is, when neither the oil level of the oil containers 13a and 13b is below the third oil level (S108: NO), the oil return control is executed. (S109). As a result, the rotation speeds of the compressors 11 and 12 are changed based on the detection results of the second detection units OLS-1b and OLS-2b, and the amount of oil in the oil containers 13a and 13b increases.

Subsequently, it is determined whether or not a predetermined period has elapsed from the time when the oil return control is executed. As a result, if the predetermined time has not elapsed, the oil return control is continuously performed until the predetermined period elapses. Then, when the oil return control is executed for a predetermined period (S110: YES), the process returns to step S102 in FIG. 5 and the subsequent processing is performed.

On the other hand, if it is determined in step S108 that any third detection unit is off (S108: YES), the refrigeration system 300 is temporarily stopped (S111). This control is, for example, an oil amount abnormality detection signal (a signal for stopping the refrigeration system) from the oil amount adjustment control unit 50 to the control unit (not shown) that controls the system start and stop in the control device 100. It is realized by outputting.

Subsequently, it is determined whether or not the number of times that the third detection unit is determined to be off is the first time. As a result, when the third detection unit was turned off for the first time (S112: YES), an inching operation of driving a fan or a valve to increase the amount of oil in the oil containers 13a and 13b was executed for a predetermined time (S113). ) After that, in order to restart the refrigerating system 300, the process returns to step S101 of FIG. 5 and the subsequent processing is performed.

On the other hand, if the third detection unit is not turned off for the first time (S112: NO), it is assumed that an abnormality has occurred in the refrigeration system 300, and the refrigeration system 300 is kept stopped and the administrator resolves the abnormality. (S114).

Subsequently, it is determined whether or not the abnormality generated in the refrigeration system 300 has been resolved (S115). If the abnormality has not been resolved (S115: NO), the abnormal stop state is continued until it is determined that the abnormality has been resolved.

On the other hand, when the abnormality is resolved (S115: YES), the process returns to step S101 of FIG. 5 and the subsequent processing is repeated.

As described above, according to the oil amount adjusting device, the oil amount adjusting method, the oil amount adjusting program, and the refrigerating system according to the present embodiment, the first detection unit OLS-1a and OLS-2a, the second detection unit OLS. The oil level heights of the oil containers 13a and 13b are detected stepwise by -1b and OLS-2b, and the third detection units OLS-1c and OLS-2c, respectively, and based on these detection results, each oil container 13a and The amount of oil in 13b is adjusted by the oil amount adjustment control unit 50. This makes it possible to keep the amount of oil in each of the oil containers 13a and 13b at an appropriate amount.

Although the present disclosure has been described above using the embodiments, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various changes or improvements can be made to the above embodiments without departing from the gist of the invention, and the modified or improved forms are also included in the technical scope of the present disclosure. Moreover, you may combine the said embodiment as appropriate.
Further, the flow of each process described in the above embodiment is also an example, and unnecessary steps are deleted, new steps are added, or the process order is changed within the range not deviating from the gist of the present disclosure. May be good.

For example, in the above-described embodiment, the case where oil is supplied from the accumulator 14 to the compressors 11 and 12 has been described, but the present invention is not limited to this example. For example, as shown in FIG. 7, the oil container 13a and the oil container 13b are connected by the oil leveling pipe OEP1, and the opening and closing of the oil is controlled by using the valve OE-V1 provided on the oil leveling pipe OEP1 to control the oil leveling. Control and oil return control may be performed.

Hereinafter, the oil amount adjustment control when the oil is supplied through the oil leveling pipe OEP1 will be described. Further, in the following description, for convenience, the oil level height of the oil container 13a is lower than the first oil level, and the oil level height of the oil container 13b is higher than the first oil level. do. That is, the state in which the amount of oil in the oil container 13a is smaller than the amount of oil in the oil container 13b is exemplified.
When the oil leveling control is executed in this state, the oil amount adjustment control unit 50 opens the valve OE-V1 and further increases the rotation speed of the compressor 11 to reduce the pressure in the compressor 11. As a result, the refrigerating machine oil moves from the compressor 12 to the compressor 11 via the oil leveling pipe OEP1, and the bias of the refrigerating machine oil between the compressors 11 and 12 is eliminated. Further, the oil amount adjustment control unit 50 starts the oil leveling operation, and after a predetermined time elapses, returns the rotation speed of the compressor to the original value and ends the oil leveling control.

Further, in the present embodiment, with respect to the oil leveling control and the oil return control, the oil leveling control and the like are terminated when each control is continuously performed for a predetermined period, but the present invention is not limited to this example. For example, each control may be stopped when the detection result of each detection unit satisfies a specific condition.

Further, regarding the installation position of the oil containers 13a and 13b, in the present embodiment, the oil containers 13a and 13b are connected to the compressors 11 and 12 by the communication pipes CP1 to CP4, but the present invention is not limited to this. For example, the oil containers 13a and 13b may be provided inside the compressors 11 and 12. The oil containers 13a and 13b are not limited to a specific configuration such as an oil pod or an oil pack, and may be any one that stores refrigerating machine oil.

Further, the procedure for adjusting the amount of oil shown in FIGS. 5 to 6 is an example, and for example, unnecessary steps may be deleted, new steps may be added, or the processing order may be changed.

The oil amount adjusting device and the refrigerating system, the oil amount adjusting method, and the oil amount adjusting program according to the present disclosure described above are grasped as follows, for example.
The oil amount adjusting device (200) according to the present disclosure is provided with a plurality of compressors (11, 12) and a plurality of oils for supplying oil to the corresponding compressors. It is an oil amount adjusting device applied to the system (300) including the containers (13a, 13b), and is provided in each oil container, and the oil level of the oil container is from the first oil level which is a standard for oil leveling control. The first detection unit (OLS-1a, OLS-2a) that detects that the oil is below the surface and the oil level of each oil container are provided below the first detection unit, and the oil level of the oil container is the standard for oil return control. The second detection unit (OLS-1b, OLS-2b) for detecting that the oil level is below the second oil level, and the oil in the oil container provided below the second detection unit in each oil container. The third detection unit (OLS-1c, OLS-2c) that detects that the surface is below the third oil level, which is the reference for abnormality detection, the first detection unit, the second detection unit, and the third detection unit. A control unit (50) for adjusting the amount of oil in the oil container based on the detection result of the unit is provided.

According to the oil amount adjusting device according to the present disclosure, the oil amount in each oil container is adjusted based on the detection results of the first detection unit, the second detection unit, and the third detection unit. In this way, the oil level of the oil container is detected stepwise by the first to third detection units, and the oil amount of the oil container is adjusted by the control unit based on these detection results, so that the oil amount of the oil container is adjusted. Can be kept in an appropriate amount. In particular, since the second detection unit is provided between the first detection unit and the third detection unit, even if the amount of oil in the oil container rapidly decreases after the detection by the first detection unit, the third detection unit is provided. Before the detection unit detects an abnormality, the second detection unit detects that the oil in the oil container is decreasing. This makes it possible to reduce the frequency with which the oil level falls below the third oil level, which is the standard for detecting an abnormality.

In the oil amount adjusting device according to the present disclosure, when the control unit detects that the oil level is below the first oil level by the first detection unit, the oil level is below the first oil level. Oil leveling control is performed to supply oil to the oil container that is detected to be present.

According to the oil amount adjusting device according to the present disclosure, when the first detection unit detects that the oil level is below the first oil level, the oil level is below the first oil level. Oil is supplied to the oil container in which is detected. This eliminates the bias in the amount of oil between the oil containers.

In the oil amount adjusting device according to the present disclosure, the control unit performs oil leveling control by changing the rotation speeds of a plurality of compressors, and is the first from the time when the oil leveling control is performed until a predetermined period elapses. Even when the detection unit detects that the oil level is below the first oil level, the oil leveling control is not performed.

According to the oil amount adjusting device according to the present disclosure, the frequency of performing oil leveling control can be limited. This makes it possible to limit the frequency with which the number of revolutions of the compressor is forcibly increased or decreased due to the amount of oil, and it is possible to suppress the failure or performance deterioration of the compressor due to the oil leveling control. ..

In the oil amount adjusting device according to the present disclosure, when the second detection unit detects that the oil level of the oil container is lower than the second oil level, the control unit sets the oil level to the second oil level. Oil return control is performed to supply oil to the oil container detected to be below the level.

According to the oil amount adjusting device according to the present disclosure, when the second detection unit detects that the oil level is below the second oil level, the oil level is below the second oil level. Oil is supplied to the oil container in which is detected. For example, when the oil leveling control based on the detection of the first detection unit is performed at a predetermined interval, the amount of oil in the oil container may rapidly decrease during the interval period. Even in such a case, if the second detection unit detects a decrease in the oil level of the oil container, the oil return control is performed. This makes it possible to perform oil return control based on the detection result of the second detection unit before the abnormality is detected by the third detection unit. As a result, it is possible to prevent abnormal stoppage in advance, and it is possible to suppress the frequency of abnormal stoppage.

In the oil amount adjusting device according to the present disclosure, the control unit stops the operation of the system when the third detection unit detects that the oil level of the oil container is lower than the third oil level.

According to the oil amount adjusting device according to the present disclosure, when the third detection unit detects that the oil level is below the third oil level, the operation of the system is stopped. In this way, since the system is not operated in a state where the amount of oil in the oil container is insufficient, it is possible to prevent deterioration of the performance of the device and occurrence of failure.

In the oil amount adjusting device according to the present disclosure, the control unit controls the oil supply to supply the oil to the oil container when the system is restarted after the system is stopped, and after the oil supply control, the oil container is controlled by the third detection unit. When it is detected that the oil level of No. 3 is below the third oil level, the operation of the system is stopped.

According to the oil amount adjusting device according to the present disclosure, when the third detection unit detects that the oil level is below the third oil level, the operation of the system is stopped. In this way, since the system is not operated in a state where the amount of oil in the oil container is insufficient, it is possible to prevent deterioration of the performance of the device and occurrence of failure.

In the oil amount adjusting device according to the present disclosure, each oil container is installed inside the corresponding compressor.

According to the oil amount adjusting device according to the present disclosure, since the oil container is installed inside the compressor, the configuration of the system can be simplified.

The refrigeration system according to the present disclosure includes a plurality of compressors for compressing the refrigerant, a plurality of oil containers provided corresponding to each compressor for supplying oil to the corresponding compressors, and heat exchange. It includes an evaporator that evaporates the refrigerant, a compressor that condenses the refrigerant by heat exchange, and the oil amount adjusting device described above.

The oil amount adjusting method according to the present disclosure is applied to a system including a plurality of compressors and a plurality of oil containers provided corresponding to each compressor and for supplying oil to the corresponding compressors. This is a method of adjusting the amount of oil, in which the oil level of the oil container is detected to be below the first oil level, which is the standard for oil leveling control, and in each oil container, the oil container is used. In the process of detecting that the oil level of the oil is below the second oil level, which is the standard for oil return control, and in each oil container, the oil level of the oil container is lower than the third oil level, which is the standard for detecting abnormalities. It has a step of detecting that it is below and a step of adjusting the amount of oil in the oil container based on the detection result of each step.

The oil amount adjustment program according to the present disclosure is applied to a system including a plurality of compressors and a plurality of oil containers provided for each compressor and for supplying oil to the corresponding compressors. This is an oil amount adjustment program that detects that the oil level of the oil container is below the first oil level, which is the standard for oil leveling control, in each oil container, and in each oil container, the oil container. In each oil container, the oil level of the oil container is lower than the third oil level, which is the standard for detecting abnormalities. The computer is made to execute the process of detecting that the oil is below and the process of adjusting the amount of oil in the oil container based on the detection result of each process.

2: Showcases 11, 12: Compressors 11a, 12a: First-stage compression units 11b, 12b: Second-stage compression units 13a, 13b: Oil container 14, 21, 22: Accumulators 15a, 15b: Oil separators 16a, 16b : Gas coolers 17a, 17b: Fan 50: Oil amount adjustment control unit 51: CPU
52: ROM
53: RAM
54: Hard disk drive 55: Communication unit 58: Bus 80: Heat exchanger 100: Control device 200: Oil amount adjusting device 300: Refrigerating system OLS-1a, OLS-2a: First detection unit OLS-1b, OLS-2b: 2nd detection unit OLS-1c, OLS-2c: 3rd detection unit MP01, MP02: Discharge pipe MP10: Gas pipe MP11: Gas-liquid two-phase pipe MP12: Liquid pipe MP13: Return pipe MP14, MP15: Suction pipe BP11, BP12 : Hot gas bypass pipe CP1, CP2, CP3, CP4: Communication pipe RP11, RP12: Oil return pipe IP10, IP11, IP12: Piping OEP1: Oil leveling pipe SC-V1, HG-V1, HG-V2, R-V1, R -V2, OE-V1: Valve CV1, CV2: Check valve

Claims (10)

An oil amount adjusting device applied to a system including a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. ,
A first detection unit provided in each of the oil containers and detecting that the oil level of the oil container is below the first oil level which is a reference for oil leveling control.
In each oil container, a second detection unit provided below the first detection unit and detecting that the oil level of the oil container is below the second oil level which is a reference for oil return control. ,
In each of the oil containers, a third detection unit provided below the second detection unit and detecting that the oil level of the oil container is below the third oil level as a reference for abnormality detection, and
A control unit that adjusts the amount of oil in the oil container based on the detection results of the first detection unit, the second detection unit, and the third detection unit.
An oil amount adjusting device equipped with. When the first detection unit detects that the oil level is below the first oil level, the control unit detects that the oil level is below the first oil level. The oil amount adjusting device according to claim 1, wherein the oil leveling control for supplying oil to the oil container is performed. The control unit performs the oil leveling control by changing the rotation speeds of the plurality of compressors, and the oil leveling control is performed by the first detection unit from the time when the oil leveling control is performed until a predetermined period elapses. The oil amount adjusting device according to claim 2, wherein the oil leveling control is not performed even when it is detected that the surface is below the first oil level. When the second detection unit detects that the oil level of the oil container is below the second oil level, the control unit has the oil level below the second oil level. The oil amount adjusting device according to any one of claims 1 to 3, which controls oil return to supply oil to the oil container detected to be. Claims 1 to 4 that the control unit stops the operation of the system when the third detection unit detects that the oil level of the oil container is lower than the third oil level. The oil amount adjusting device according to any one of the above items. The control unit controls the oil supply to supply the oil to the oil container when the system is restarted after the system is stopped, and after the oil supply control, the third detection unit controls the oil in the oil container. The oil amount adjusting device according to claim 5, wherein when it is detected that the surface is below the third oil level, the operation of the system is stopped. The oil amount adjusting device according to any one of claims 1 to 6, wherein each oil container is installed inside the corresponding compressor. Multiple compressors that compress the refrigerant,
A plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors.
An evaporator that evaporates the refrigerant by heat exchange,
A condenser that condenses the refrigerant by heat exchange,
The oil amount adjusting device according to any one of claims 1 to 7.
Freezing system with. An oil amount adjusting method applied to a system including a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. ,
In each of the oil containers, a step of detecting that the oil level of the oil container is below the first oil level, which is a reference for oil leveling control, and
In each of the oil containers, a step of detecting that the oil level of the oil container is below the second oil level, which is a reference for oil return control, and
In each of the oil containers, a step of detecting that the oil level of the oil container is below the third oil level, which is a reference for detecting an abnormality, and
A process of adjusting the amount of oil in the oil container based on the detection result of each process, and a process of adjusting the amount of oil in the oil container.
How to adjust the amount of oil. An oil amount adjustment program applied to a system including a plurality of compressors and a plurality of oil containers provided corresponding to each of the compressors and for supplying oil to the corresponding compressors. ,
In each of the oil containers, a process for detecting that the oil level of the oil container is below the first oil level, which is a reference for oil leveling control, and
In each of the oil containers, a process for detecting that the oil level of the oil container is below the second oil level, which is a reference for oil return control, and
In each of the oil containers, a process of detecting that the oil level of the oil container is below the third oil level, which is a reference for detecting an abnormality,
Based on the detection result of each step, the process of adjusting the amount of oil in the oil container and
An oil level adjustment program that causes the computer to execute.

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