JP6157182B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus. In particular, the present invention relates to a configuration for preventing supercharging to the compressor.

  For example, in a refrigeration system in which a plurality of outdoor units are connected in parallel, oil leveling pipes that communicate with each other are provided at positions where the appropriate amount of oil in the compressors of each outdoor unit can be secured, and individually on the discharge side of each compressor There is an apparatus in which an oil separator is provided to separate refrigerant gas and refrigerating machine oil. The refrigerating machine oil separated by the oil separator flows through the oil return pipe and the capillary tube into the suction side pipe (suction pipe) of each compressor (for example, see Patent Document 1).

Japanese Examined Patent Publication No. 7-122522

  In a conventional refrigeration apparatus having a compressor as described in Patent Document 1, when the pressure in the compressor container becomes the suction pressure, oil is moved between the compressors by an oil equalizing pipe. Therefore, the required oil amount can be secured. For this reason, when a compressor with a large operating capacity and a compressor with a small operating capacity are communicated with each other, the higher the operating capacity, the larger the oil rises and the more oil is used, but the pressure in the container also decreases. Therefore, the oil moves from the compressor having a small operating capacity, and the variation in the amount of the refrigerating machine oil in the compressor is eliminated, so that the necessary oil amount can be ensured.

  However, when this structure is applied to a refrigeration system having a compressor in which the pressure in the compressor container becomes the discharge pressure, the pressure in the compressor having a large operating capacity becomes higher than the pressure in the compressor having a small operating capacity. The refrigeration oil moves in the direction of the smaller compressor. In a compressor with a small operating capacity, the refrigeration oil decreases and the required amount of oil cannot be secured. Therefore, in a compressor having a large operating capacity, the refrigerating machine oil is supercharged, leading to a rise in the suction pipe temperature.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain a refrigeration apparatus that prevents refrigeration oil from returning excessively to the compressor.

The refrigeration apparatus according to the present invention includes a compressor that compresses and discharges the sucked refrigerant, a condenser that condenses the refrigerant by heat exchange, a decompression apparatus that decompresses the refrigerant related to condensation, and a refrigerant that relates to decompression. An evaporator that exchanges heat with air to evaporate the refrigerant and an accumulator that is connected to the suction side of the compressor and stores excess refrigerant are connected by piping to form a refrigerant circuit. An oil separator that separates the oil discharged from the compressor in between, the return pipe that sends the oil separated by the oil separator to the suction side pipe of the compressor, and the return pipe and the refrigerant inflow side pipe of the accumulator A return oil bypass pipe for sending oil passing through the return pipe to the accumulator, an opening / closing device for controlling passage of oil in the return oil bypass pipe, a control device for controlling opening / closing of the opening / closing device, an accumulator and a compressor, Piping connection The oil return pipe for sending the oil in the accumulator to the compressor and the oil return pipe temperature detecting device for detecting the oil return pipe temperature, which is the temperature of the oil return pipe, are provided. If it judges, it will control so that oil may pass through a return oil bypass pipe .

  According to the refrigeration apparatus according to the present invention, the return oil bypass pipe that connects the return pipe and the inflow side of the accumulator is provided, and the oil flowing through the return pipe also flows to the accumulator. The amount of oil flowing directly to the machine 2 can be reduced, and supercharging to the compressor 2 can be prevented.

It is a block diagram which shows schematically an example of a structure of the freezing apparatus 100 which concerns on Embodiment 1 of this invention. It is the figure which showed the relationship between the oil quantity inside the compressor supposing the compressor used as the supercharging, and the discharge oil quantity from a compressor. It is a block diagram which shows the structure of the control system which concerns on Embodiment 1 of this invention. It is a figure explaining the opening / closing control of the bypass solenoid valve 26 which the control apparatus 30 performs based on the suction pipe temperature which the suction pipe temperature sensor 41 detected. It is a figure explaining the opening / closing control of the bypass solenoid valve 26 which the control apparatus 30 performs based on the shell lower temperature detected by the shell lower temperature sensor. It is a figure explaining the opening / closing control of the bypass solenoid valve 26 which the control apparatus 30 performs based on the oil return pipe temperature which the oil return pipe temperature sensor 43 detected. It is a block diagram which shows schematically an example of a structure of the freezing apparatus 200 which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the control system which concerns on Embodiment 2 of this invention. It is a block diagram which summarizes and shows an example of a structure of the freezing apparatus 300 which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the control system which concerns on Embodiment 3 of this invention. It is a figure explaining the opening degree control of the bypass adjustment valve 28 which the control apparatus 30 performs based on the suction pipe temperature which the suction pipe temperature sensor 41 detected. It is a figure explaining the opening degree control of the bypass adjustment valve 28 which the control apparatus 30 performs based on the shell lower temperature which the shell lower temperature sensor 42 detected. It is a figure explaining the opening degree control of the bypass adjustment valve 28 which the control apparatus 30 performs based on the oil return pipe temperature which the oil return pipe temperature sensor 43 detected. It is a block diagram which shows schematically an example of a structure of the freezing apparatus 400 which concerns on Embodiment 4 of this invention. It is a block diagram which shows the structure of the control system which concerns on Embodiment 4 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, in the following drawings including FIG. 1, the size relationship of each component may be different from the actual one. In addition, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common to the whole text of the embodiments described below. . Further, in the following description, subscripts such as “a” and “b” attached to the reference numerals may be omitted if it is not necessary to distinguish between them. And the form of the component represented by the whole text of specification is an illustration to the last, Comprising: It is not limited to the form described in the specification.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram schematically illustrating an example of a configuration of a refrigeration apparatus 100 according to Embodiment 1 of the present invention. Based on FIG. 1, the structure and operation | movement of the freezing apparatus 100 which concerns on Embodiment 1 of this invention are demonstrated. The refrigeration apparatus 100 is used for a supermarket, a convenience store showcase, a refrigerator, a freezer, and the like, for example. And the refrigeration apparatus 100 in this Embodiment reduces the supercharging of the compressor 2, and aims at the improvement of the quality of the compressor 2. FIG.

  As shown in FIG. 1, the refrigeration apparatus 100 of the present embodiment includes a plurality of (two in FIG. 1) outdoor units 1a and 1b. The outdoor units 1a and 1b are connected in parallel to each other through a liquid pipe 23 and a gas pipe 24 to an indoor unit 20 having an expansion valve 21 and an evaporator 22 that are decompression devices. Here, although FIG. 1 shows an example in which two outdoor units 1 (compressors 2) are connected in parallel, three or more units may be used. Moreover, although there are few effects, it is applicable even if there is only one outdoor unit 1 (compressor 2). In FIG. 1, the case where there is one indoor unit 20 is shown as an example, but usually a plurality of indoor units 20 are connected.

  The outdoor units 1a and 1b include compressors 2a and 2b, oil separators 3a and 3b, condensers 4a and 4b, accumulators 5a and 5b, and oil regulators 6a and 6b, respectively. In the refrigeration apparatus 100, the condensers 4a and 4b are connected to the liquid piping 23 that communicates with the expansion valve 21, and the accumulators 5a and 5b are connected to the gas piping 24 that communicates with the evaporator 22 via the distributor 25a. In this way, the refrigerant circuit is formed by connecting the component devices by piping. And a refrigerating machine oil (henceforth oil) contained in a refrigerant and a refrigerant circulates in a refrigerant circuit.

  The compressors 2a and 2b compress the refrigerant and discharge the high-temperature and high-pressure refrigerant. The compressors 2a and 2b are low-pressure shell types such as scrolls in which the inside of the shell has a low pressure, are variable capacity inverter compressors, and have a structure in which oil is held in the compressor shell. The oil separators 3a and 3b are provided on the discharge sides of the compressors 2a and 2b, and separate oil discharged together with the refrigerant from the compressors 2a and 2b from the refrigerant. The condensers 4a and 4b condense the refrigerant by exchanging heat between the refrigerant discharged from the compressors 2a and 2b and air supplied from, for example, a blower (not shown). The accumulators 5a and 5b are installed on the suction side of the compressors 2a and 2b, and are for storing surplus refrigerant among the refrigerant circulating in the refrigeration cycle. The oil regulators 6a and 6b are for controlling the amount of liquid returned to the compressors 2a and 2b and keeping the amount of oil in the compressors 2a and 2b at a specified amount.

  The expansion valve 21 decompresses and expands the refrigerant circulating in the refrigerant circuit. The expansion valve 21 may be configured by a valve whose opening degree can be variably controlled, for example, an electronic expansion valve. The evaporator 22 evaporates the refrigerant by exchanging heat between the refrigerant decompressed by the expansion valve 21 and, for example, air supplied from a blower (not shown).

  The distributor 25a distributes the refrigerant and oil flowing through the gas pipe 24 to the accumulators 5a and 5b.

  The accumulators 5 a and 5 b are connected to each other by an oil equalizing pipe 10 in order to correct a deviation in the amount of oil stored in each accumulator 5. The oil equalizing pipe 10 is provided with an electromagnetic valve 12a for opening and closing the oil flow. Here, the front end portions 10a and 10b of the oil leveling pipe 10 are inserted through the bottoms of the accumulators 5a and 5b, and the end inlet of the oil leveling pipe 10 has a predetermined height from the bottom surface of the accumulators 5a and 5b. It is installed at the same height. Thereby, the minimum amount of oil which can always be secured in the accumulators 5a and 5b can be set. The minimum amount of oil that can always be secured in one of the accumulators is usually about 1 to 2 liters.

  Further, the gas refrigerant (including oil that cannot be separated) in the accumulators 5a and 5b is sucked into the compressors 2a and 2b through the gas suction pipes 7a and 7b. The gas suction pipes 7a and 7b are U-shaped at one end inserted into the accumulators 5a and 5b, and have oil return holes 8a and 8b in the U-shaped pipe portions, respectively. However, the U-shaped tube portion inserted into the accumulators 5a and 5b may be a straight tube, and the straight tube portion may not include the oil return holes 8a and 8b. Furthermore, oil return pipes 13a and 13b for returning the oil stored in the accumulators 5a and 5b to the compressors 2a and 2b are connected to the bottoms of the accumulators 5a and 5b through one end, and the other end is an oil regulator. 6a and 6b.

  The oil regulators 6a and 6b and the compressors 2a and 2b are connected by suction pipes 14a and 14b and pressure equalizing pipes 15a and 15b. Inside the oil regulators 6a and 6b, there are provided float valves (not shown) that interlock with the float. When the oil level is below the specified height, the float valve is opened and oil is supplied to the compressors 2a and 2b. When the oil level reaches the specified height, the float valve is shut off, and the supply of oil to the compressors 2a and 2b is stopped. Here, the oil separated and stored in the oil separators 3a and 3b is gas-intaked through the return pipes 29a and 29b through the capillary tubes (not shown) or directly without the capillary tubes. Oil is returned to the compressors 2a and 2b via the pipes 7a and 7b.

  In the refrigerating apparatus 100 of the present embodiment, the required amount of oil is the amount of oil to be secured as an appropriate amount in the compressors 2a and 2b, and the amount of oil present in the piping, equipment, etc. of the refrigerant circuit leaving the compressor And the total amount. Actually, the amount of oil to be filled in the refrigerant circuit is filled more than the total amount. Excess oil is stored in the accumulators 5a and 5b.

  Next, the flow of the refrigerant in the refrigeration apparatus 100 in the present embodiment will be described. The flow of the refrigerant is indicated by solid line arrows in FIG. The high-temperature and high-pressure gas refrigerant discharged from the compressors 2a and 2b is condensed and liquefied by the condensers 4a and 4b via the oil separators 3a and 3b. Thereafter, the liquefied refrigerant is reduced in pressure by the expansion valve 21 of the indoor unit 20 through the liquid pipe 23 to become a two-phase refrigerant, and is evaporated by the evaporator 22. The gasified refrigerant then enters the accumulators 5a and 5b of the outdoor units 1a and 1b via the gas pipe 24 and the distributor 25a. The refrigerant that has entered the accumulators 5a and 5b and is further evaporated and vaporized is sucked into the compressors 2a and 2b through the gas suction pipes 7a and 7b. In this way, the refrigerant circulates through the refrigerant circuit.

  Next, the flow of oil in the refrigeration apparatus 100 in the present embodiment will be described. The flow of oil is indicated by broken arrows in FIG. About 90% of the oil discharged together with the gas refrigerant from the compressors 2a and 2b is separated from the refrigerant by the oil separators 3a and 3b. The separated oil flows into the gas suction pipes 7a and 7b through the return pipes 29a and 29b, and is returned to the compressors 2a and 2b. The oil that has not been separated by the oil separators 3a and 3b passes through the condensers 4a and 4b, the liquid pipe 23, the expansion valve 21, the evaporator 22, the gas pipe 24, and the distributor 25a together with the refrigerant in order, to the outdoor unit 1a. 1b flows again into the accumulators 5a and 5b.

  In the accumulators 5a and 5b, the oil and the gas refrigerant are separated, and the separated oil stays at the bottom of the accumulators 5a and 5b. The oil staying in the accumulators 5a and 5b is supplied from the oil return pipes 13a and 13b to the compressors 2a and 2b via the oil regulators 6a and 6b. In order to make the oil level heights of the oil regulators 6a, 6b and the compressors 2a, 2b equal, pressure equalizing pipes 15a, 15b through which gas flows are connected. And the surplus oil in the freezing apparatus 100 is stored in the accumulators 5a and 5b of the low-pressure part.

  In the refrigerant flow from the accumulators 5a and 5b to the compressors 2a and 2b, pressure loss due to friction loss in the piping occurs. The differential pressure corresponding to the pressure loss becomes a driving force for the oil to flow from the accumulators 5a and 5b to the compressors 2a and 2b. Moreover, the oil level head difference resulting from the level difference between the oil level in the accumulators 5a and 5b and the oil level in the compressors 2a and 2b also affects the oil flow. If the oil level of the accumulators 5a and 5b is above the oil level in the compressors 2a and 2b, the supply of oil from the accumulators 5a and 5b to the compressors 2a and 2b is promoted. On the contrary, if it is in the lower part, the oil supply is inhibited.

  In actual operation, due to variations in the amount of oil contained in the high-pressure gas refrigerant discharged from the compressor 2, variations in the mounting angle that occur when assembling the distributor 25a, etc., the inside of the outdoor unit 1a and the outdoor unit 1b The oil in is not even. Further, the refrigeration apparatus 100 is generally used in an environment where the indoor temperature of the indoor unit 20 is +15 to −55 ° C. and the evaporation temperature of the evaporator 22 is about +10 to −65 ° C. The fins of the heat exchanger part of the evaporator 22 used in the low temperature range are frosted, and when the amount of frost increases, the heat exchange capacity of the evaporator 22 decreases, the internal temperature rises, and the product in the internal compartment The quality of will deteriorate.

  Therefore, when using the refrigeration apparatus 100 in a low temperature region, a defrosting operation is performed in which the frost of the evaporator 22 is melted several times a day (the number of times can be arbitrarily determined by the product in the warehouse and the temperature setting). . For details of one defrosting operation, first, the operation of the refrigeration apparatus 100 is stopped (about 20 to 30 minutes). In the meantime, for example, in a state where the fan of the evaporator 22 is stopped, the heater inside the heat exchanger fins is energized and heated to melt the attached frost. As a method for melting frost, besides the heater, there are a method of supplying heat from the inside of the evaporator by flowing a high-temperature and high-pressure refrigerant gas, and a method of simply stopping the fan of the evaporator 22.

  The inside of the evaporator 22 immediately after melting the frost is hot. If the fan is rotated in this state, high-temperature air may flow into the space to be cooled, which may increase the temperature of the space. In addition, high-temperature air may be cooled by the cold air in the space and re-frost on the product, which may affect the quality of the product. Therefore, for about 3 to 20 minutes immediately after melting the frost, the refrigeration apparatus 100 is operated with the fan that allows air to pass through the evaporator 22 is stopped. In about 3 to 20 minutes, the temperature inside the evaporator 22 is cooled. Thereafter, the fan of the evaporator 22 is operated to prevent the rise in the internal temperature to a minimum.

  However, while the fan of the evaporator 22 is not operated, the refrigeration apparatus 100 is operating. During this time, heat exchange on the evaporator 22 side is not sufficient. For this reason, in the refrigeration apparatus 100, the refrigerant is not converted into evaporative gas on the evaporator 22 side, and remains as a two-phase refrigerant. Of this two-phase refrigerant, particularly about 10% of the liquid refrigerant that could not be separated by the oil separator 3 (oil staying in the gas pipe 24) is returned to the outdoor unit 1 side (liquid back operation). ) This stagnant oil cannot be evenly distributed to a plurality of outdoor units 1 in a transient operation that recools the internal temperature that has risen within the time of melting and the effect of the above-mentioned variation and frost. Can be considered.

  For example, when only one of the plurality of compressors 2 is activated, the oil and liquid refrigerant discharged from all the compressors 2 are returned to the outdoor unit 1 of the activated compressor 2 at a time. . Then, the returned oil and liquid refrigerant are stored in one accumulator 5. The returned oil is the amount of oil discharged from all the compressors 2. The accumulator 5 overflows faster due to the large amount of oil and the liquid back operation. And the oil which flows into the compressor 2 will also become supercharging.

  FIG. 2 is a diagram showing the relationship between the amount of oil inside the compressor and the amount of oil discharged from the compressor (oil circulation amount) assuming a compressor that has become supercharged. In FIG. 2, the horizontal axis represents the amount of oil (L) inside the compressor, and the vertical axis represents the amount of oil discharged from the compressor (oil circulation rate%).

  As shown in FIG. 2, the amount of oil discharged from the compressor increases as the amount of supercharged oil increases (the amount of oil inside the compressor increases). In the inverter compressor, the higher the operating frequency, the greater the refrigerant circulation amount and the greater the amount of discharged oil.

  The discharged oil is mixed with the high-temperature refrigerant gas, separated by the oil separator 3, and returned to the gas suction pipe 7 side of the compressor 2. Therefore, as the amount of oil increases, the oil cannot be cooled with the low-temperature refrigerant gas passing through the gas suction pipe 7, and the oil and refrigerant gas sucked by the compressor 2 become higher in temperature. By sucking in the high-temperature refrigerant gas, the compressor 2 may cause an excessive increase in the motor temperature, deterioration of parts in the compressor 2, and the like, and the quality of the compressor 2 may be reduced.

  Therefore, in the refrigeration apparatus 100 including a plurality of outdoor units 1, oil return bypass pipes 27a and 27b are provided in the outdoor units 1a and 1b, respectively. The oil separated by the oil separators 3a and 3b is divided into a flow path that flows into the gas suction pipes 7a and 7b and a flow path that flows through the oil return bypass pipes 27a and 27b and flows into the accumulators 5a and 5b. Divide. Further, bypass solenoid valves 26a and 26b serving as opening / closing devices are provided between the oil return bypass pipes 27a and 27b.

  By providing the oil return bypass pipes 27a and 27b and the bypass solenoid valves 26a and 26b, the amount of oil returned to the compressor 2 can be adjusted, and thus the temperature rise of the refrigerant sucked by the compressor 2 is suppressed. can do. Moreover, the quality fall by the supercharging to the compressor 2 can be suppressed. Here, in the present embodiment, the oil separator 3 and the inflow side piping of the accumulator 5 are not directly connected by the return piping 29. This is because the oil separator 3 having good oil separation efficiency has a larger amount of oil return to the compressor 2 than the oil regulator 6. If the oil separator 3 and the inflow side piping of the accumulator 5 are directly connected by piping, the amount of oil returning to the compressor 2 is reduced. For this reason, during operation under a high compressor load condition, oil exhaustion in the compressor 2 becomes a problem, and the compressor 2 may break down. Therefore, in the present embodiment, the return pipe 29 for returning oil to the gas suction pipe 7 side of the compressor 2 and the return oil bypass pipe 27 for returning oil to the inflow side pipe of the accumulator 5 are divided.

<Control system>
FIG. 3 is a block diagram showing the configuration of the control system according to Embodiment 1 of the present invention. The control device 30 controls the refrigeration apparatus 100 (particularly the outdoor units 1a and 1b). In particular, the control device 30 of the present embodiment controls each device in order to adjust the oil returned to the compressor 2. The control device 30 includes an operation unit 500, a storage unit 501, and a control unit 502.

  The operation unit 500 includes, for example, input means for an operator to input settings, instructions, and the like related to the operation of the refrigeration apparatus 100. The storage unit 501 stores data used temporarily or for a long time for the control unit 502 to perform processing. For example, data related to settings input via the operation unit 500 is stored. The control unit 502 is configured by a microcomputer having a CPU, for example. In the present embodiment, for example, the opening and closing of the bypass solenoid valves 26a and 26b is appropriately controlled to perform a process for adjusting the suction pipe temperature.

  As shown in FIGS. 1 and 3, the present embodiment includes suction pipe temperature sensors 41a and 41b, under-shell temperature sensors 42a and 42b, and oil return pipe temperature sensors 43a and 43b. These temperature sensors are sensors that detect a temperature that is used as a judgment material in the opening / closing control of the bypass solenoid valves 26a and 26b.

  The suction pipe temperature sensors 41a and 41b are temperature sensors (suction side temperature detection devices) that detect the temperature of the gas suction pipes 7a and 7b (the temperature of the gas refrigerant flowing through the gas suction pipes 7a and 7b). The shell lower temperature sensors 42a and 42b are temperature sensors that detect the temperature under the compressor 2 (shell). The oil return pipe temperature sensors 43a and 43b are temperature sensors that detect the temperature of oil flowing through the oil return pipes 13a and 13b. Each temperature sensor includes temperature data related to detection in a signal and sends the signal to the control device 30.

<Operation: When bypass solenoid valve 26 is open>
Next, opening / closing control of the bypass electromagnetic valve 26 by the control device 30 will be described. For example, by opening the bypass electromagnetic valve 26 during the operation of the outdoor unit 1, a part of the oil separated by the oil separator 3 passes through the oil return bypass pipe 27 and flows into the accumulator 5. The accumulator 5 serves as a buffer, so that all oil does not flow into the gas suction pipe 7 and is returned to the compressor 2. Further, since the inside of the accumulator 5 is in a low temperature / low pressure state, the temperature of the oil flowing into the accumulator 5 decreases. In this state, the refrigerant flows into the gas suction pipe 7 together with the refrigerant and is returned to the compressor 2. As described above, the oil does not become supercharged oil, and the temperature of the refrigerant flowing into the compressor 2 can be suppressed.

<Control method 1 of bypass solenoid valves 26a and 26b>
FIG. 4 is a view for explaining the opening / closing control of the bypass solenoid valve 26 performed by the control device 30 based on the suction pipe temperature detected by the suction pipe temperature sensor 41.

  For example, the operation unit 500 is operated to set the suction pipe temperature as a trigger to 30 ° C. and the temperature differential to 2 ° C. The temperature differential is provided to prevent hunting associated with opening and closing of the bypass solenoid valve 26. In consideration of the fact that the piping shape and length of the refrigeration apparatus 100 vary depending on the apparatus, measurement error of the sensor, etc., the operation unit 500 can change the numerical value of the temperature differential and set the trigger suction pipe temperature. .

  Then, when the suction pipe temperature sensor 41 detects at regular intervals and determines that the suction pipe temperature is 32 ° C. or higher, the bypass solenoid valve 26 is opened so that oil flows also to the oil return bypass pipe 27. So that the temperature of the sucked refrigerant does not rise.

  Further, after the bypass solenoid valve 26 is opened, the suction pipe temperature detected by the suction pipe temperature sensor 41 based on the suction pipe temperature detected at regular intervals is 28 ° C. or less in consideration of the temperature differential. When judged, the bypass solenoid valve 26 is closed so that oil does not pass through the oil return bypass pipe 27. Opening and closing control is repeated as described above to prevent supercharging to the compressor 2 and to prevent the temperature of the gas suction pipe 7 from rising excessively.

<Control Method 2 for Bypass Solenoid Valves 26a and 26b>
FIG. 5 is a diagram for explaining the opening / closing control of the bypass solenoid valve 26 performed by the control device 30 based on the shell lower temperature detected by the shell lower temperature sensor 42.

  For example, by operating the operation unit 500, the under-shell temperature serving as a trigger is set to 35 ° C., and the temperature differential is set to 2 ° C. As in the case of the intake pipe temperature, considering that the piping shape, length, etc. of the refrigeration apparatus 100 differ depending on the apparatus, the operation unit 500 can change the numerical value of the temperature differential and set the temperature below the shell as a trigger. ing.

  Then, when the shell lower temperature sensor 42 detects at regular intervals and determines that the shell lower temperature is equal to or higher than 37 ° C., the bypass solenoid valve 26 is opened so that oil flows also to the oil return bypass pipe 27. So that the temperature of the sucked refrigerant does not rise.

  Further, after the bypass solenoid valve 26 is opened, if it is determined that the under-shell temperature detected by the under-shell temperature sensor 42 is 33 ° C. or less based on the under-shell temperature detected at regular intervals, the bypass solenoid valve 26 Is closed so that oil does not pass through the oil return bypass pipe 27.

<Control Method 3 for Bypass Solenoid Valves 26a and 26b>
FIG. 6 is a diagram for explaining the opening / closing control of the bypass solenoid valve 26 performed by the control device 30 based on the oil return pipe temperature detected by the oil return pipe temperature sensor 43.

  For example, by operating the operation unit 500, the oil return pipe temperature serving as a trigger is set to 35 ° C., and the temperature differential is set to 2 ° C. As in the case of the suction pipe temperature, considering that the piping shape and length of the refrigeration apparatus 100 vary depending on the apparatus, the operation unit 500 can change the numerical value of the temperature differential and set the trigger oil return pipe temperature. ing.

  Then, when the oil return pipe temperature sensor 43 detects every predetermined time and determines that the oil return pipe temperature is 37 ° C. or higher, the bypass solenoid valve 26 is opened so that oil flows also to the oil return bypass pipe 27. So that the temperature of the sucked refrigerant does not rise.

  Further, after opening the bypass solenoid valve 26, if it is determined that the oil return pipe temperature detected by the oil return pipe temperature sensor 43 is 33 ° C. or less based on the oil return pipe temperature detected at regular intervals, the bypass solenoid valve 26 Is closed so that oil does not pass through the oil return bypass pipe 27.

  Here, although not particularly limited, for example, it is not necessary to perform opening / closing control using all of the suction pipe temperature sensor 41, the shell lower temperature sensor 42, and the oil return pipe temperature sensor 43. For example, when there is a sensor that is not provided for cost reduction, the opening / closing control may be performed based on the detection of another sensor. In addition, for example, when the piping structure differs depending on the type and installation location of the refrigeration apparatus 100, the detection accuracy of the sensor may differ depending on the position. Therefore, it is possible to perform opening / closing control by selecting a sensor with high detection accuracy. Also good. At this time, a sensor to be used may be selected and set by the operation unit 500. Conversely, on the basis of the temperatures detected by the suction pipe temperature sensor 41, the shell lower temperature sensor 42, and the oil return pipe temperature sensor 43, the opening / closing control is performed (the condition for opening and closing the valve is satisfied if the temperature related to any detection is met). If it is satisfied, the valve may be closed).

  As described above, according to the refrigeration apparatus 100 of Embodiment 1, the return oil bypass pipe 27 that connects the return pipe 29 and the inflow side of the accumulator 5 is provided, and the oil flowing through the return pipe 29 is supplied to the accumulator 5. Therefore, the amount of oil flowing from the oil separator 3 to the suction pipe 14 can be reduced, and supercharging to the compressor 2 can be prevented. At this time, the control device 30 controls the opening and closing of the bypass electromagnetic valve 26 so as to control the passage of oil to the oil return bypass pipe 27 leading to the accumulator 5, so that the oil separated by the oil separator 3 is removed. It is possible to prevent the refrigerating machine oil from being supercharged to the compressor 2 without returning all to the compressor 2. Moreover, since the temperature of the refrigerant | coolant which the compressor 2 suck | inhales can be made low, damage to the compressor 2 can be prevented. At this time, the present invention can be applied regardless of the type of the compressor.

  Further, since the suction pipe temperature detected by the suction pipe temperature sensor 41 is used when the control device 30 controls the opening and closing of the bypass solenoid valve 26, the bypass solenoid valve is directly determined from the temperature of the refrigerant sucked by the compressor 2. 26 can be controlled to open and close.

  Further, when the control device 30 controls opening and closing of the bypass electromagnetic valve 26, the under-shell temperature detected by the under-shell temperature sensor 42 is used, so that the bypass electromagnetic valve is determined from the temperature of oil (refrigerant) sucked by the compressor 2. 26 can be controlled to open and close.

  In addition, when the control device 30 controls the opening and closing of the bypass solenoid valve 26, the oil return pipe temperature detected by the oil return pipe temperature sensor 43 is used, so that the bypass solenoid valve 26 is opened and closed from the temperature of the oil returned to the compressor 2. Can be controlled.

Embodiment 2. FIG.
FIG. 7 is a configuration diagram schematically showing an example of the configuration of the refrigeration apparatus 200 according to Embodiment 2 of the present invention. In the refrigeration apparatus 200 according to the present embodiment, a case where three outdoor units 1a, 1b, and 1c are connected in parallel will be described. In FIG. 3, the constituent elements of the outdoor unit 1c are the same as the constituent elements of the outdoor units 1a and 1b. Further, distributors 25a and 25b are provided to branch the refrigerant passing through the gas pipe 24 into three. The distributor 25a distributes the refrigerant to the outdoor unit 1a side and the outdoor units 1b and 1c side, and the distributor 25b distributes the refrigerant to the outdoor unit 1b side and the outdoor unit 1c side. The operation of the refrigeration apparatus 200 and the operation of the outdoor unit 1c accompanying the operation of the refrigeration apparatus 200 are the same as the operations in the outdoor units 1a and 1b described in the first embodiment.

  FIG. 8 is a block diagram showing a configuration of a control system according to Embodiment 2 of the present invention. In FIG. 8, the same reference numerals as those in FIG. 3 denote the same operations as those described in the first embodiment. As shown in FIG. 8, in the present embodiment, signals related to the temperatures detected by the temperature sensors are also sent from the suction pipe temperature sensor 41c, the under-shell temperature sensor 42c, and the oil return pipe temperature sensor 43c. And the control apparatus 30 performs opening / closing control of the bypass electromagnetic valve 26c. The method for opening / closing control is the same as that described in the first embodiment. As described above, also in the refrigeration apparatus 200 having three or more outdoor units 1, the oil return bypass pipe 27 is provided, and the bypass electromagnetic valve 26 is controlled to be opened and closed, thereby preventing supercharging to the compressor 2. be able to.

Embodiment 3 FIG.
FIG. 9 is a configuration diagram schematically showing an example of the configuration of the refrigeration apparatus 300 according to Embodiment 3 of the present invention. In FIG. 9, the same reference numerals as in FIG. 1 perform the same operations as those described in the first embodiment.

  In FIG. 9, the refrigeration apparatus 300 is provided with bypass adjustment valves 28a and 28b instead of the bypass electromagnetic valves 26a and 26b described in the first embodiment. The bypass adjustment valves 28 a and 28 b are configured by, for example, electronic expansion valves that can change the opening degree based on an instruction from the control device 30. For this reason, the amount of refrigerant passing through the oil return bypass pipes 27a and 27b can be finely adjusted.

<Control system>
FIG. 10 is a block diagram showing a configuration of a control system according to Embodiment 3 of the present invention. 10 that have the same reference numerals as those in FIG. 3 perform the same operations as those described in the first embodiment. As shown in FIG. 10, in the present embodiment, the control device 30 opens the opening of the bypass adjustment valve 28 based on signals sent from the suction pipe temperature sensor 41, the shell lower temperature sensor 42, and the oil return pipe temperature sensor 43. Take control.

<Operation: When bypass adjustment valve 28 is open>
Next, the opening degree control of the bypass adjustment valve 28 by the control device 30 will be described. Similar to the bypass solenoid valve 26 of the first embodiment, for example, by opening the bypass adjustment valve 28 during the operation of the outdoor unit 1, the oil separated by the oil separator 3 passes through the oil return bypass pipe 27. It also flows into the accumulator 5. For this reason, the temperature of the refrigerant flowing into the compressor 2 can be suppressed without being supercharged.

<Control Method 1 of Bypass Adjustment Valves 28a and 28b>
FIG. 11 is a diagram illustrating the opening degree control of the bypass adjustment valve 28 performed by the control device 30 based on the suction pipe temperature detected by the suction pipe temperature sensor 41.

  For example, the operation unit 500 is operated to set the suction pipe temperature as a trigger to 30 ° C. and the temperature differential to 2 ° C. The temperature differential is provided to prevent hunting associated with a change in the opening degree of the bypass adjustment valve 28. In consideration of the fact that the piping shape and length of the refrigeration apparatus 300 vary depending on the apparatus, measurement errors of the sensor, etc., the operation unit 500 can change the numerical value of the temperature differential and set the trigger suction pipe temperature. .

  When the suction pipe temperature sensor 41 detects at regular intervals and determines that the suction pipe temperature is 32 ° C. or higher, the opening of the bypass adjustment valve 28 is opened and the oil return bypass pipe 27 is also filled with oil. So that the temperature of the sucked refrigerant does not rise.

  Further, after opening the opening of the bypass adjustment valve 28, the suction pipe temperature detected by the suction pipe temperature sensor 41 is 28 ° C. or less in consideration of the temperature differential based on the suction pipe temperature detected at regular intervals. When it is determined that there is, the opening degree of the bypass adjustment valve 28 is closed, so that the oil does not pass through the oil return bypass pipe 27. The opening degree control is repeated as described above to prevent supercharging to the compressor 2 and prevent the temperature of the gas suction pipe 7 from rising excessively.

<Control Method 2 for Bypass Adjustment Valves 28a and 28b>
FIG. 12 is a diagram illustrating the opening degree control of the bypass adjustment valve 28 performed by the control device 30 based on the shell lower temperature detected by the shell lower temperature sensor 42.

  For example, by operating the operation unit 500, the under-shell temperature serving as a trigger is set to 35 ° C., and the temperature differential is set to 2 ° C. As in the case of the suction pipe temperature, considering that the piping shape, length, etc. of the refrigeration apparatus 300 differ depending on the apparatus, the operation unit 500 can change the numerical value of the temperature differential and set the temperature under the shell as a trigger. ing.

  When the shell lower temperature sensor 42 detects at regular intervals and determines that the shell lower temperature is equal to or higher than 37 ° C., the opening of the bypass adjustment valve 28 is opened and oil is returned to the oil return bypass pipe 27 as well. So that the temperature of the sucked refrigerant does not rise.

  Further, after opening the opening of the bypass adjustment valve 28, the shell under temperature detected by the shell under temperature sensor 42 is 33 ° C. or less in consideration of the temperature differential based on the shell under temperature detected every predetermined time. When it is determined that there is, the opening degree of the bypass adjustment valve 28 is closed, so that the oil does not pass through the oil return bypass pipe 27. The opening degree control is repeated as described above to prevent supercharging to the compressor 2 and prevent the temperature of the gas suction pipe 7 from rising excessively.

<Control Method 3 for Bypass Adjustment Valves 28a and 28b>
FIG. 13 is a diagram for explaining the opening degree control of the bypass adjustment valve 28 performed by the control device 30 based on the oil return pipe temperature detected by the oil return pipe temperature sensor 43.

  For example, by operating the operation unit 500, the oil return pipe temperature serving as a trigger is set to 35 ° C., and the temperature differential is set to 2 ° C. As in the case of the suction pipe temperature, considering that the piping shape, length, etc. of the refrigeration apparatus 300 vary depending on the apparatus, the operation unit 500 can be used to change the numerical value of the temperature differential and to set the trigger oil return pipe temperature. ing.

  When it is determined that the oil return pipe temperature detected by the oil return pipe temperature sensor 43 is equal to or higher than 37 ° C., the opening of the bypass adjustment valve 28 is opened and the oil is supplied to the oil return bypass pipe 27 as well. The temperature of the refrigerant to be used should not be raised.

  Furthermore, after opening the bypass adjustment valve 28, the oil return pipe temperature detected by the oil return pipe temperature sensor 43 based on the oil return pipe temperature detected every predetermined time is 33 ° C. or less in consideration of the temperature differential. If it judges, the opening degree of the bypass adjustment valve 28 will be made into a closing direction, and oil will not pass through the return oil bypass pipe 27. FIG. The opening degree control is repeated as described above to prevent supercharging to the compressor 2 and prevent the temperature of the gas suction pipe 7 from rising excessively.

  Here, as in the first embodiment, for example, the opening degree control can be performed using any one or all of the suction pipe temperature sensor 41, the under-shell temperature sensor 42, and the oil return pipe temperature sensor 43.

  As described above, the oil return bypass pipe 27 is provided, and the control device 30 controls the opening of the bypass adjustment valve 28 to control the passage of oil to the oil return bypass pipe 27 leading to the accumulator 5. The oil separated by the oil separator 3 is not all returned to the compressor 2, and the compressor 2 can be prevented from being supercharged with refrigerating machine oil. Moreover, since the temperature of the refrigerant | coolant which the compressor 2 suck | inhales can be made low, damage to the compressor 2 can be prevented. At this time, the present invention can be applied regardless of the type of the compressor.

  Further, when the control device 30 controls the opening degree of the bypass adjustment valve 28, the suction pipe temperature detected by the suction pipe temperature sensor 41 is used, so that the bypass is directly performed from the temperature of the refrigerant sucked by the compressor 2. The opening degree of the regulating valve 28 can be controlled.

  Further, when the control device 30 controls the opening degree of the bypass adjustment valve 28, the under-shell temperature detected by the under-shell temperature sensor 42 is used, so that the bypass from the temperature of the oil (refrigerant) sucked by the compressor 2 is bypassed. The opening degree of the regulating valve 28 can be controlled.

  Further, when the control device 30 controls the opening degree of the bypass adjustment valve 28, the oil return pipe temperature detected by the oil return pipe temperature sensor 43 is used, so that the bypass adjustment valve 28 is determined from the temperature of the oil returned to the compressor 2. Can be controlled.

Embodiment 4 FIG.
FIG. 14 is a configuration diagram schematically illustrating an example of the configuration of the refrigeration apparatus 400 according to Embodiment 4 of the present invention. In the refrigeration apparatus 400 of the present embodiment, a case where three outdoor units 1a, 1b, and 1c are connected in parallel will be described. In FIG. 14, the constituent elements of the outdoor unit 1c are the same as the constituent elements of the outdoor units 1a and 1b. Further, distributors 25a and 25b are provided to branch the refrigerant passing through the gas pipe 24 into three. The distributor 25a distributes the refrigerant to the outdoor unit 1a side and the outdoor units 1b and 1c side, and the distributor 25b distributes the refrigerant to the outdoor unit 1b side and the outdoor unit 1c side. About the operation | movement of the outdoor unit 1c accompanying operation | movement of the freezing apparatus 400 and the freezing apparatus 400, it is the same as that of the outdoor unit 1a, 1b demonstrated in Embodiment 1,3.

  FIG. 15 is a block diagram showing a configuration of a control system according to Embodiment 4 of the present invention. 15 that have the same reference numerals as those in FIG. 10 perform the same operations as those described in the third embodiment. As shown in FIG. 15, in the present embodiment, signals relating to the temperatures detected by the temperature sensors are also sent from the suction pipe temperature sensor 41c, the under-shell temperature sensor 42c, and the oil return pipe temperature sensor 43c. And the control apparatus 30 performs opening / closing control of the bypass adjustment valve 28c. The method for opening / closing control is the same as that described in the third embodiment. As described above, also in the refrigeration apparatus 400 having three or more outdoor units 1, the oil return bypass pipe 27 is provided and the opening of the bypass adjustment valve 28 is controlled to prevent supercharging to the compressor 2. And so on.

  1, 1a, 1b, 1c outdoor unit, 2, 2a, 2b, 2c compressor, 3, 3a, 3b, 3c oil separator, 4, 4a, 4b, 4c condenser, 5, 5a, 5b, 5c accumulator 6, 6a, 6b, 6c Oil regulator, 7, 7a, 7b, 7c Gas suction pipe, 8, 8a, 8b, 8c Oil return hole, 10 Oil equalizing pipe, 10a, 10b, 10c Tip, 12, 12a, 12b Solenoid valve, 13, 13a, 13b, 13c Oil return pipe, 14, 14a, 14b, 14c Suction pipe, 15, 15a, 15b, 15c Pressure equalizing pipe, 20 Indoor unit, 21 Expansion valve (pressure reducing means), 22 Evaporator, 23 Liquid piping, 24 Gas piping, 25, 25a, 25b Distributor, 26, 26a, 26b, 26c Bypass solenoid valve, 27, 27a, 27b, 27c Oil return bypass pipe, 28, 28a 28b, 28c Bypass adjustment valve, 29, 29a, 29b, 29c Return pipe, 30 control device, 41, 41a, 41b, 41c Intake pipe temperature sensor, 42, 42a, 42b, 42c Under shell temperature sensor, 43, 43a, 43b , 43c Oil return pipe temperature sensor, 100, 200, 300, 400 Refrigeration apparatus, 500 operation unit, 501 storage unit, 502 control unit.

Claims (5)

A compressor for compressing and discharging the sucked refrigerant;
A condenser for condensing the refrigerant by heat exchange;
A decompression device for decompressing the refrigerant associated with the condensation;
An evaporator that evaporates the refrigerant by exchanging heat between the refrigerant and the air related to decompression;
Connected to the suction side piping of the compressor, and connected to an accumulator for storing excess refrigerant to form a refrigerant circuit;
An oil separator between the compressor and the condenser for separating the oil discharged from the compressor;
A return pipe for sending the oil separated by the oil separator to a suction side pipe of the compressor;
A return oil bypass pipe that connects the return pipe and the refrigerant inflow side pipe of the accumulator, and sends oil passing through the return pipe to the accumulator ;
An opening and closing device for controlling the passage of the oil in the oil return bypass pipe;
A control device for controlling opening and closing of the switchgear;
An oil return pipe that pipe-connects the accumulator and the compressor and sends the oil in the accumulator to the compressor;
An oil return pipe temperature detection device for detecting the oil return pipe temperature, which is the temperature of the oil return pipe,
When the control device determines that the oil return pipe temperature is equal to or higher than a predetermined temperature, the control device controls the oil to pass through the oil return bypass pipe . A flow rate control device for controlling the amount of the oil passing through the oil return bypass pipe;
The refrigerating apparatus according to claim 1, further comprising a control device that performs flow rate control of the flow rate control device. A suction side temperature detecting device for detecting a suction pipe temperature which is a temperature of the suction side pipe;
3. The refrigeration apparatus according to claim 2 , wherein the control device performs control so that the oil passes through the oil return bypass pipe when it is determined that the suction pipe temperature is equal to or higher than a predetermined temperature. It further comprises an under-shell temperature detection device that detects an under-shell temperature that is a temperature at the bottom of the compressor,
Wherein the controller, when the shell bottom temperature is determined to be greater than or equal to the predetermined temperature, the refrigeration apparatus according to claim 2 or 3, wherein the controller controls so as to pass the oil into the oil return bypass pipe. The refrigeration apparatus according to any one of claims 1 to 4 , wherein a plurality of the compressors are piped in parallel.

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