JP2008139001A - Refrigerating plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the amount of oil deposited on a refrigerant pipe by collecting extra oil (surplus refrigerating machine oil) discharged from a compressor. <P>SOLUTION: To an oil separator 22, an oil reservoir container 32 is connected into which separated refrigerating machine oil flows to be reserved. Between the oil reservoir container 32 and a suction pipe 2b of the compressor 21, an oil outflow pipe 35 is connected in which the refrigerating machine oil flows from the oil reservoir container 32. An on-off valve 33 is provided in the oil outflow pipe 35. The extra oil amount of the refrigerating machine oil stored in the compressor 21 is calculated in accordance with the length of a communication pipe in a refrigerant circuit 20, and the on-off valve 33 is changed over into an opened condition for every predetermined time depending on the surplus oil amount. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a refrigeration apparatus, and particularly relates to measures for recovering excess oil in a compressor.

Conventionally, a refrigeration apparatus having a compressor and performing a refrigeration cycle is known. For example, the refrigeration apparatus of Patent Document 1 includes a refrigerant circuit that is a closed circuit in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe. In this refrigerant circuit, the high-pressure refrigerant discharged from the compressor returns to the compressor through a condensation process, an expansion process, and an evaporation process in order.
JP 2001-304699 A

    Incidentally, in the above-described compressor casing, generally, a refrigerating machine oil storage section for lubricating each sliding section is provided. And in a compressor, a part of refrigerating machine oil supplied to each sliding part will be discharged with the compressed high-pressure refrigerant. Therefore, in general, an oil separator is provided in the discharge pipe of the compressor to separate the refrigerant and the refrigerating machine oil, and the separated refrigerating machine oil is returned to the suction side of the compressor.

    However, since the refrigeration oil cannot be completely separated in the oil separator, the refrigeration oil that has not been separated flows through the refrigerant circuit together with the refrigerant. A part of the refrigerating machine oil flowing through the refrigerant circuit returns to the compressor together with the refrigerant, but the rest adheres to the refrigerant pipe and the like. Therefore, since the amount of return of the refrigeration oil in the compressor is insufficient in this state, poor lubrication occurs, and conventionally, the amount of refrigeration oil estimated in advance by the amount adhering to the refrigerant pipe or the like is stored in the compressor. .

    Here, the amount of refrigerating machine oil to be accommodated in the compressor may be changed according to the total length of the refrigerant pipe of the refrigeration apparatus to be mounted. However, this requires a great deal of labor and labor, so the total length of the refrigerant pipe. Is generally set to the same amount according to the longest. However, when the compressor is mounted on a refrigeration apparatus having a short refrigerant pipe length, excess refrigeration oil is generated. If it does so, the quantity of the refrigeration oil which flows out out of a compressor and adheres to refrigerant | coolant piping etc. will increase. As a result, there is a problem that the flow loss of the refrigerant in the refrigerant pipe increases and the load on the compressor increases.

    The present invention has been made in view of such a point, and an object of the present invention is to recover surplus oil (surplus refrigerating machine oil) discharged from the compressor in a refrigeration apparatus having a compressor, and to perform refrigerant piping or the like. Is to reduce the amount of oil adhering to the surface.

    The first invention communicates with the compressor (21), the oil separator (22) connected to the discharge side of the compressor (21), the oil separator (22), and the oil separator ( 22) an oil sump container (32) for storing the refrigerating machine oil separated in (22); and an oil supply container (32) connected to the suction side of the compressor (21) and having an on-off valve (33). And a connecting pipe (35) for returning the refrigeration oil in the oil reservoir (32) to the suction side of the compressor (21), and a refrigerant circuit (20) for performing a vapor compression refrigeration cycle. Refrigeration equipment.

    In the above invention, the refrigerant is circulated in the refrigerant circuit (20) to perform the vapor compression refrigeration cycle. That is, the high-pressure refrigerant discharged from the compressor (21) returns to the compressor (21) again through the condensation process (heat radiation process), the expansion process, and the evaporation process in order. The compressor (21) contains refrigeration oil. Most of the refrigeration oil that flows out of the compressor (21) together with the refrigerant is separated by the oil separator (22). A small amount of refrigerating machine oil that has not been separated by the oil separator (22) flows together with the refrigerant, a part of which remains attached to the refrigerant pipe or the like, and the rest is sucked into the compressor (21) together with the refrigerant.

    All the refrigerating machine oil separated by the oil separator (22) is stored (recovered) in the oil sump container (32). That is, most of the refrigerating machine oil that has flowed out of the compressor (21) is stored in the oil reservoir (32). In this state, the refrigerating machine oil is stored in the oil sump container (32) and does not return to the compressor (21). Therefore, the refrigerating machine oil in the compressor (21) is insufficient, resulting in poor lubrication. Therefore, by opening the on-off valve (33) of the connection pipe (35), the refrigeration oil in the oil reservoir (32) flows to the suction side of the compressor (21). Therefore, the amount of refrigerating machine oil stored in the oil sump container (32) is adjusted by adjusting the opening / closing time of the on-off valve (33) during operation. Thereby, even if surplus refrigeration oil is stored in the compressor (21), the surplus oil can be stored (recovered) in the oil reservoir (32). Then, the amount of refrigerating machine oil flowing through the oil separator (22) and flowing through the refrigerant circuit (20) is suppressed, and the amount of oil adhering to the refrigerant pipe is reduced.

    In a second aspect based on the first aspect, the oil separator (22) and the oil reservoir (32) are connected by a flow pipe (31) through which the refrigeration oil of the oil separator (22) flows. Has been. On the other hand, the oil reservoir container (32) is disposed below the oil separator (22).

    In the above invention, as shown in FIG. 1, the oil sump container (32) is located below the oil separator (22), so that the refrigerating machine oil separated by the oil separator (22) is its own weight. It flows into the sump container (32) through the flow pipe (31). Therefore, it is not necessary to separately provide means for allowing the refrigeration oil to flow from the oil separator (22) into the oil reservoir (32). That is, the oil sump container (32) of the present invention is provided at a position where the refrigerating machine oil flows down from the oil separator (22) by its own weight.

    In a third aspect based on the first aspect, a gas refrigerant is sealed in the oil reservoir (32). The refrigerant circuit (20) has an on-off valve (36), one end communicating with the gas refrigerant space in the oil reservoir (32) and the other end on the on-off valve (33) in the connection pipe (35). ) And a pressure reducing pipe (38) for decompressing the oil sump container (32).

    In the above invention, as shown in FIG. 2, the pressure reducing pipe (38) communicates the oil reservoir (32) with the suction side of the compressor (21). Therefore, when the on-off valve (36) is opened, the gas refrigerant in the oil reservoir (32) flows to the suction side of the compressor (21) through the decompression pipe (38), and the oil reservoir (32) is depressurized. The Then, the pressure inside the oil separator (22) is almost the same as the discharge pressure of the compressor (21), and a pressure difference is generated between the oil separator (22) and the oil reservoir (32). Due to this pressure difference, the refrigerating machine oil in the oil separator (22) flows into the oil reservoir (32). Thereby, the refrigerating machine oil separated by the oil separator (22) is stored (recovered) in the oil reservoir container (32).

    According to a fourth invention, in the first invention, the surplus oil amount of the refrigerating machine oil stored in the compressor (21) is calculated based on a refrigerant pipe length of the refrigerant circuit (20), and the surplus oil is calculated. Control means (40) for opening the on-off valve (33) of the connection pipe (35) at predetermined time intervals determined in advance according to the amount is provided.

    In the above invention, the surplus oil amount of the refrigerating machine oil is calculated based on the refrigerant pipe length of the actual refrigerant circuit (20). The amount of refrigerating machine oil to be accommodated in the longest refrigerant pipe length assumed in consideration of the amount of refrigerating machine oil accommodated in the compressor (21) is taken into consideration. Therefore, when the actual refrigerant pipe length is shorter than expected, an excess oil amount is generated by that short amount, and the excess oil amount is calculated from the actual refrigerant pipe length. In addition, the refrigerant | coolant piping length said here, for example, as shown in FIG. 1, piping from the both ends of an indoor heat exchanger (26) to the 2nd port of a four-way selector valve (23), and an expansion mechanism (25) The length of the pipes up to and the tube length of each heat exchanger (24, 26).

    And in this invention, predetermined time is preset according to the calculated excess oil amount, and the on-off valve (33) switches to an open state for every predetermined time. When the on-off valve (33) is opened, refrigeration oil flows from the oil reservoir (32) through the connection pipe (35) into the compressor (21). Thereby, the amount of refrigerating machine oil stored in the oil reservoir container (32) is adjusted. That is, by changing the opening / closing timing of the on-off valve (33), the amount of refrigerating machine oil in the oil reservoir (32) is adjusted, and a desired surplus oil amount can be stored in the oil reservoir (32).

    According to a fifth invention, in the third invention, the surplus oil amount of the refrigerating machine oil stored in the compressor (21) is calculated based on the refrigerant pipe length of the refrigerant circuit (20), and the surplus oil is calculated. Provided with a control means (40) for opening the on-off valve (33) of the connecting pipe (35) and closing the on-off valve (36) of the pressure reducing pipe (38) at a predetermined time according to the amount It is.

    In the above invention, similarly to the above-described fourth invention, the surplus oil amount of the refrigerating machine oil is calculated based on the actual refrigerant pipe length of the refrigerant circuit (20). A predetermined time is preset according to the calculated surplus oil amount, and the on-off valve (33) of the connecting pipe (35) is opened at every predetermined time, and the on-off valve (36) of the pressure reducing pipe (38). Switches to the closed state. That is, when the on-off valve (36) of the pressure reducing pipe (38) is opened, the on-off valve (33) of the connecting pipe (35) is closed, and when the on-off valve (36) of the pressure reducing pipe (38) is closed, the connecting pipe The open / close valve (33) of (35) opens.

    When the on-off valve (36) of the pressure reducing pipe (38) is in the open state, the oil reservoir (32) is depressurized and the refrigerating machine oil of the oil separator (22) is stored in the oil reservoir (32). Further, when the on-off valve (33) of the connection pipe (35) is in the open state, the refrigeration oil flows from the oil reservoir (32) to the suction side of the compressor (21). That is, by changing the opening / closing timing of each on-off valve (33, 36), the inflow amount and outflow amount of refrigerating machine oil in the oil sump container (32) are adjusted. Therefore, surplus refrigerating machine oil can be stored in the oil sump container (32).

    In a sixth aspect based on the fourth or fifth aspect, the control means (40) estimates the amount of attachment of refrigeration oil to the refrigerant pipe according to the refrigerant pipe length of the refrigerant circuit (20). And the excess oil amount of the refrigerating machine oil accommodated in the compressor (21) is calculated from the estimated adhesion amount.

    In said invention, the adhesion amount of the refrigeration oil with respect to the refrigerant | coolant piping is estimated from actual refrigerant | coolant piping length. Then, the difference between the estimated adhesion amount and the refrigeration oil adhesion amount with respect to the assumed longest refrigerant pipe length is calculated as a surplus of the refrigeration oil accommodated in the compressor (21).

    According to a seventh aspect, in the fourth or fifth aspect, the control means (40) is configured to increase the predetermined time as the calculated surplus oil amount increases.

    In the above invention, the larger the amount of surplus oil stored in the oil reservoir (32), the longer the predetermined time. As the predetermined time increases, the amount of refrigerating machine oil flowing out from the oil reservoir (32) decreases. That is, during operation, the time during which the on-off valve (33) of the connection pipe (35) is open is shortened. Thereby, the amount of refrigerating machine oil stored in the oil sump container (32) increases.

    In an eighth aspect based on the fourth or fifth aspect, the heat source side heat exchanger (24), the compressor (21), the oil separator (22), and the oil sump container (32) are accommodated. Heat source unit (11) and a utilization unit (12) in which a utilization side heat exchanger (26) is accommodated. The refrigerant pipe length of the refrigerant circuit (20) is the length of the connecting pipe (2c, 2d) that connects the heat source unit (11) and the utilization unit (12).

    In the above invention, in the refrigerant circuit (20), the refrigerant condensed (heat dissipated) in the heat source side heat exchanger (24) flows through the connecting pipe (2d) to the use side heat exchanger (26) and evaporates. . The evaporated refrigerant returns to the compressor (21) through the communication pipe (2c). Alternatively, in the refrigerant circuit (20), the refrigerant discharged from the compressor (21) flows through the connecting pipe (2c) to the use side heat exchanger (26) and condenses (heatsinks), and then connects to the connecting pipe. It flows through (2d) to the heat source side heat exchanger (24) and evaporates.

    Generally, in the refrigeration apparatus (10), the length of the connecting pipes (2c, 2d) varies depending on the installation location. That is, depending on the installation location of the refrigeration apparatus (10), the connecting pipe (2c, 2d) becomes longer, and the amount of oil attached to the pipe increases accordingly. Therefore, in the present invention, the surplus oil amount of the refrigeration oil accommodated in the compressor (21) is calculated based on the length of the connecting pipe (2c, 2d). Therefore, the excess oil amount of refrigeration oil is grasped exactly.

    According to a ninth aspect, in the eighth aspect, a plurality of the use units (12) are provided and connected in parallel to each other. And the refrigerant | coolant piping length of the said refrigerant circuit (20) is an average length of the connection piping (2c, 2d) which connects the said heat-source unit (11) and each utilization unit (12).

    In the above invention, the connecting pipes (2c, 2d) are branched and connected to each utilization unit (12). In this case, the length of the connecting pipe (2c, 2d) for each usage unit (12) differs depending on the installation location of the usage unit (12). Therefore, in the present invention, the surplus oil amount of the refrigeration oil accommodated in the compressor (21) is calculated based on the average length of the connecting pipes (2c, 2d) of each usage unit (12). Therefore, the excess oil amount of refrigeration oil is grasped without excess or deficiency.

    As described above, according to the present invention, the oil reservoir (32) in which the refrigerating machine oil separated by the oil separator (22) flows in and stored, and the refrigeration stored in the oil reservoir (32) are stored. A connecting pipe (35) for returning the machine oil to the suction side of the compressor (21) is provided. Therefore, all the refrigerating machine oil that has flowed out of the compressor (21) and separated by the oil separator (22) is collected in the oil reservoir (32), and a part of the collected refrigerating machine oil can be optionally compressed ( 21). As a result, during operation, the excess refrigeration oil can always be stored in the oil sump container (32), and the amount of refrigeration oil flowing through the refrigerant circuit (20) through the oil separator (22) is suppressed. can do. Therefore, it can prevent that refrigeration oil adheres to refrigerant | coolant piping more than necessary. As a result, the flow loss of the refrigerant in the refrigerant piping can be reduced, and the heat exchange efficiency of each heat exchanger (24, 26) can be improved.

    According to the second invention, since the oil reservoir (32) is arranged below the oil separator (22), the refrigerating machine oil in the oil separator (22) is taken up by its own weight in the oil reservoir ( 32). Thereby, it is not necessary to separately provide a means for allowing the refrigerating machine oil to flow from the oil separator (22) to the oil reservoir (32), and the refrigeration apparatus can be made compact and the cost can be reduced.

    According to the third aspect of the invention, since the pressure reducing pipe (38) for reducing the pressure of the oil reservoir (32) is provided, there is no problem in the arrangement relationship between the oil reservoir (32) and the oil separator (22). The refrigerating machine oil of the oil separator (22) can be caused to flow into the oil reservoir (32). Therefore, the degree of freedom of installation of the oil sump container (32) can be increased, and the refrigeration apparatus can be simplified.

    According to the fourth, fifth and sixth inventions, the opening / closing timing of the on-off valve (33) is determined based on the surplus oil amount calculated according to the total length of the pipe. It is possible to reliably store surplus refrigeration oil in 32). That is, the amount of refrigerating machine oil necessary for lubricating the compressor (21) can be reliably returned to the compressor (21). Accordingly, excess refrigeration oil can be recovered while preventing poor lubrication of the compressor (21).

    According to the seventh aspect of the invention, the longer the calculated surplus oil amount, the longer the closing time of the on-off valve (33) of the connection pipe (35). In other words, the smaller the calculated excess oil amount, the shorter the closing time of the on-off valve (33) of the connecting pipe (35). Thereby, the on-off valve (33) can be appropriately controlled according to the surplus oil amount, and surplus refrigerating machine oil can be reliably stored in the oil sump container (32).

    According to the eighth aspect of the invention, the surplus oil amount of the refrigerating machine oil is calculated based on the length of the connecting pipe (2c, 2d) connecting the heat source unit (11) and the utilization unit (12). The amount of surplus oil can be grasped appropriately according to the installation location. Therefore, excess refrigeration oil in the compressor (21) can be reliably recovered.

    According to the ninth invention, when a plurality of usage units (12) are connected in parallel, the surplus of refrigeration oil is based on the average length of the connecting pipes (2c, 2d) of each usage unit (12). The amount of oil was calculated. Therefore, the excess oil amount can be grasped without excess or deficiency, and excess refrigeration oil in the compressor (21) can be reliably recovered.

    Embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
A first embodiment of the present invention will be described. As shown in FIG. 1, the air-conditioning apparatus (10) of this embodiment includes a refrigerant circuit (20) that performs a vapor compression refrigeration cycle by circulating refrigerant. This air conditioner (10) constitutes a refrigeration apparatus according to the present invention.

    The refrigerant circuit (20) includes a compressor (21), an oil separator (22), a four-way switching valve (23), an outdoor heat exchanger (24), an expansion mechanism (25), an indoor And a heat exchanger (26). The compressor (21), the four-way switching valve (23), and the like are connected to each other by a refrigerant pipe.

    Specifically, in this refrigerant circuit (20), the suction pipe (2b) of the compressor (21) is connected to the third port of the four-way switching valve (23). The discharge pipe (2a) of the compressor (21) is connected to the first port of the four-way switching valve (23) via the oil separator (22). The oil separator (22) is for separating the high-pressure refrigerant discharged from the compressor (21) and the refrigerating machine oil. The fourth port of the four-way selector valve (23) is connected to one end of the outdoor heat exchanger (24). The other end of the outdoor heat exchanger (24) is connected to one end of the indoor heat exchanger (26) via the expansion mechanism (25). The other end of the indoor heat exchanger (26) is connected to the second port of the four-way switching valve (23).

    The compressor (21) is constituted by, for example, a hermetic high-pressure dome type scroll compressor. That is, the inside of the casing of the compressor (21) is a high pressure space. And although not shown in figure, the storage part of the refrigeration oil is provided in the bottom part of the casing.

    The outdoor heat exchanger (24) and the indoor heat exchanger (26) are so-called cross fin type fin-and-tube heat exchangers. That is, in these heat exchangers (24, 26), a copper tube passes through a plurality of aluminum fins. An outdoor fan (27) and an indoor fan (28) are provided in the vicinity of the outdoor heat exchanger (24) and the indoor heat exchanger (26), respectively. The outdoor heat exchanger (24) constitutes a heat source side heat exchanger in which the refrigerant exchanges heat with the outdoor air taken in by the outdoor fan (27). The indoor heat exchanger (26) constitutes a use side heat exchanger in which the refrigerant exchanges heat with the indoor air taken in by the indoor fan (28). The expansion mechanism (25) is an expansion valve with a variable opening.

    The four-way switching valve (23) includes a first state (state indicated by a solid line in FIG. 1) in which the first port and the fourth port communicate with each other, and the second port and the third port communicate with each other; It is configured to switch to a second state (state indicated by a broken line in FIG. 1) in which the two ports communicate and the third port and the fourth port communicate. That is, in the refrigerant circuit (20), when the four-way switching valve (23) is in the first state, the refrigerant circulates in the cooling cycle, and the outdoor heat exchanger (24) serves as a condenser (heat radiator) to exchange the heat in the room. Vessels (26) each function as an evaporator. In the refrigerant circuit (20), when the four-way switching valve (23) is in the second state, the refrigerant circulates in the heating cycle, the outdoor heat exchanger (24) serves as an evaporator, and the indoor heat exchanger (26). Each function as a condenser (heat radiator).

    The refrigerant circuit (20) is provided with a surplus oil recovery mechanism (30) as a feature of the present invention. The surplus oil recovery mechanism (30) includes an oil inflow pipe (31), an oil reservoir (32), an on-off valve (33), a capillary tube (34), and an oil outflow pipe (35).

    The oil sump container (32) constitutes a sealed container and is connected to the oil separator (22) by an oil inflow pipe (31). The oil reservoir (32) is disposed below the oil separator (22). And the oil sump container (32) is comprised so that the refrigerating machine oil isolate | separated by the oil separator (22) may flow in through the oil inflow pipe (31) with its own weight. That is, the surplus oil recovery mechanism (30) is configured to recover all the refrigerating machine oil that has flowed out of the compressor (21) and separated by the oil separator (22) into the oil reservoir (32). . The oil inflow pipe (31) constitutes a flow pipe according to the present invention.

    The oil outflow pipe (35) is connected to the bottom of the oil sump container (32) and the midway of the suction pipe (2b) of the compressor (21) to constitute a connection pipe according to the present invention. The oil outlet pipe (35) is provided with the on-off valve (33) and the capillary tube (34) in order from the oil reservoir container (32) side. In other words, in the surplus oil recovery mechanism (30), the open / close valve (33) is opened so that the refrigerating machine oil in the oil reservoir (32) passes through the oil outflow pipe (35) and the suction pipe (2b) of the compressor (21). ). The refrigerating machine oil flowing through the oil outflow pipe (35) is adjusted to a predetermined flow rate by the capillary tube (34). The on-off valve (33) is composed of a solenoid valve.

    This refrigeration apparatus (10) includes the compressor (21), oil separator (22), four-way switching valve (23), outdoor heat exchanger (24), expansion mechanism (25), outdoor fan (27) And an outdoor unit (11) in which the surplus oil recovery mechanism (30) is stored, and an indoor unit (12) in which the indoor heat exchanger (27) and the indoor fan (28) are stored. The outdoor unit (11) and the indoor unit (12) constitute a heat source unit and a utilization unit according to the present invention.

    The outdoor unit (11) and the indoor unit (12) are connected by a communication gas pipe (2c) and a communication liquid pipe (2d) which are communication pipes. Specifically, the communication liquid pipe (2d) is connected between the expansion mechanism (25) and one end of the indoor heat exchanger (26). The communication gas pipe (2c) is connected between the other end of the indoor heat exchanger (26) and the second port of the four-way switching valve (23). That is, the communication gas pipe (2c) and the communication liquid pipe (2d) constitute a part of the refrigerant circuit (20).

    The air conditioner (10) includes a controller (40). The controller (40) is provided with a surplus oil amount calculation unit (41) and an on-off valve control unit (42).

    The surplus oil amount calculation unit (41) manually inputs the total length of the communication gas pipe (2c) and the communication liquid pipe (2d) (hereinafter referred to as the communication pipe length). The surplus oil amount calculation unit (41) is configured to calculate a surplus (hereinafter referred to as surplus oil amount) of the refrigeration oil in the compressor (21) based on the input connection pipe length. Has been. That is, in this embodiment, the communication pipe length is the refrigerant pipe length according to the present invention. Specifically, the “surplus oil amount” is calculated by the following equation.

"Excess oil amount" = "Designed oil amount"-"Actual oil amount"
Here, first, the amount of attached oil means that the refrigerating machine oil flowing out from the compressor (21) flows as it is without being separated by the oil separator (22), and the refrigerant pipe and each heat exchanger (24, 26) This is an estimated amount that adheres to the tube, and is estimated according to the length of the connecting pipe. The “designed amount of attached oil” is the amount of attached oil estimated with respect to the assumed longest connection pipe length. That is, it is a fixed value that is uniformly determined for any air conditioner. The “actual machine attached oil amount” is the attached oil amount estimated with respect to the communication pipe length in the actual air conditioner (10), and is the attached amount according to the present invention. Therefore, the “surplus oil amount” is calculated in the surplus oil amount calculation unit (41) by estimating the “actual machine attached oil amount” corresponding to the input actual connection pipe length.

    The on-off valve control unit (42) controls the on-off valve (33) so that the refrigeration oil is stored in the oil sump container (32) by the amount of surplus oil calculated by the surplus oil amount calculation unit (41). To do. Specifically, the on-off valve control unit (42) opens the on-off valve (33) every predetermined time T1 determined in advance according to the excess oil amount. The predetermined time T1 is set to be longer as the calculated excess oil amount is larger. In other words, the surplus oil recovery mechanism (30) always has refrigeration oil flowing from the oil separator (22) into the sump container (32) during operation, but refrigeration oil exceeding the surplus oil amount has entered the sump container (32). In order not to be stored, the refrigeration oil is periodically returned from the oil reservoir (32) to the compressor (21). Detailed control contents will be described later.

-Driving action-
Next, the operation of the air conditioner (10) will be described. The air conditioner (10) is configured to be switchable between a cooling operation and a heating operation.

<Cooling operation>
In this cooling operation, in the refrigerant circuit (20), the refrigerant circulates in the direction indicated by the solid line arrow in FIG. 1, and a cooling cycle is performed. Specifically, the four-way selector valve (23) is set to the first state, and the opening degree of the expansion mechanism (25) is appropriately adjusted. In this state, when the compressor (21) is driven (operation is started), the high-pressure refrigerant discharged from the compressor (21) to the discharge pipe (2a) passes through the oil separator (22). To the outdoor heat exchanger (24). In the outdoor heat exchanger (24), the high-pressure refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (24) is depressurized by the expansion mechanism (25) and then flows to the indoor heat exchanger (26). In the indoor heat exchanger (26), the low-pressure refrigerant absorbs heat from the indoor air and evaporates. The room air is cooled and supplied to the room. The low-pressure refrigerant evaporated in the indoor heat exchanger (26) is drawn into the compressor (21) through the suction pipe (2b).

<Heating operation>
In this heating operation, in the refrigerant circuit (20), the refrigerant circulates in the direction indicated by the dashed arrow in FIG. 1, and a heating cycle is performed. Specifically, the four-way selector valve (23) is set to the second state, and the opening degree of the expansion mechanism (25) is adjusted as appropriate. In this state, when the compressor (21) is driven, high-pressure refrigerant is discharged from the compressor (21) to the discharge pipe (2a), and then to the indoor heat exchanger (26) via the oil separator (22). Flowing. In the indoor heat exchanger (26), the high-pressure refrigerant dissipates heat to the indoor air and condenses. The room air is heated and supplied to the room. The refrigerant condensed in the indoor heat exchanger (26) is depressurized by the expansion mechanism (25) and then flows to the outdoor heat exchanger (24). In the outdoor heat exchanger (24), the low-pressure refrigerant absorbs heat from the outdoor air and evaporates. The low-pressure refrigerant evaporated in the outdoor heat exchanger (24) is sucked into the compressor (21) from the suction pipe (2b).

<Excess oil recovery mechanism operation and controller control operation>
First, before the operation is started, the on-off valve (33) is set to the closed state, and the communication pipe length is manually input to the surplus oil amount calculation unit (41). Then, the surplus oil amount calculation unit (41) calculates the surplus oil amount.

    Next, when the operation is started, the refrigeration oil flows out of the compressor (21) together with the refrigerant, and most of the oil is separated by the oil separator (22). The separated refrigerating machine oil flows into the oil reservoir (32) through the oil inflow pipe (31) by its own weight. A small amount of refrigeration oil that has not been separated by the oil separator (22) flows through the refrigerant circuit (20) together with the refrigerant. A part of the refrigeration oil stays attached to the connecting pipe (2c, 2d) and the tubes of the heat exchangers (24, 26), and the rest returns to the compressor (21) together with the refrigerant.

    When a predetermined time T1 elapses from the start of operation, the on-off valve controller (42) switches the on-off valve (33) to the open state. During this predetermined time T1, the amount of refrigerating machine oil stored in the oil reservoir (32) increases. And when predetermined time T2 passes after switching to an open state, an on-off valve control part (42) will close an on-off valve (33) again. While the on-off valve (33) is open (during a predetermined time T2), the refrigerating machine oil flows from the oil separator (22) into the oil sump container (32), while the refrigerating machine oil from the oil sump container (32). Flows out to the suction pipe (2b) of the compressor (21) at a predetermined flow rate. Subsequently, when a predetermined time T1 elapses after the opening / closing valve (33) is closed, the opening / closing valve (33) is switched to the open state again for the predetermined time T2, and this opening / closing control is repeated. Thereby, the surplus refrigeration oil is always stored in the oil sump container (32). Further, since the predetermined time T1 becomes longer as the calculated surplus oil amount increases, the surplus refrigerating machine oil is reliably stored in the oil sump container (32).

-Effect of Embodiment 1-
According to this embodiment, the oil reservoir (32) in which the refrigerating machine oil separated by the oil separator (22) flows in and stored, and the refrigerating machine oil stored in the oil reservoir (32) are compressed by the compressor ( An oil spill pipe (35) that returns to the suction pipe (2b) of 21) is provided. Therefore, all the refrigerating machine oil that has flowed out of the compressor (21) and separated by the oil separator (22) is collected in the oil reservoir (32), and a part of the collected refrigerating machine oil can be optionally compressed ( 21). As a result, during operation, the excess refrigeration oil can always be stored in the oil sump container (32), and the amount of refrigeration oil flowing through the refrigerant circuit (20) through the oil separator (22) is suppressed. can do. Therefore, it is possible to prevent the refrigeration oil from adhering more than necessary to the communication pipes (2c, 2d) and the tubes of the heat exchangers (24, 26). As a result, the flow loss of the refrigerant in the refrigerant piping can be reduced, and the heat exchange efficiency of each heat exchanger (24, 26) can be improved.

    Further, the oil reservoir container (32) can be disposed below the oil separator (22), and the refrigerating machine oil of the oil separator (22) can be guided to the oil reservoir container (32) by its own weight. Accordingly, surplus refrigeration oil can be recovered in the oil reservoir container (32) with a simple configuration without separately providing power means for introducing the refrigerator oil from the oil separator (22) to the oil reservoir container (32). . As a result, a compact and low-cost air conditioner (10) can be provided.

    In addition, the amount of oil attached to the actual machine greatly fluctuates depending on the length of the connecting pipe. Since the amount of oil attached to the actual machine is estimated based on the length of the connecting pipe, the excess oil amount is calculated. The amount of oil can be grasped. And since the opening / closing timing of the on-off valve (33) is determined based on the calculated surplus oil amount, the refrigerating machine oil necessary for lubrication is ensured while the surplus refrigerating machine oil is reliably stored in the oil reservoir (32). Can be reliably returned to the compressor (21). Therefore, excess refrigeration oil can be recovered while preventing poor lubrication of the compressor (21).

<< Embodiment 2 of the Invention >>
A second embodiment of the present invention will be described. As shown in FIG. 2, the air conditioner (10) of the present embodiment is obtained by changing the configuration of the surplus oil recovery mechanism (30) in the first embodiment. That is, in this embodiment, the pressure reducing pipe (38) is provided in the surplus oil recovery mechanism (30) of the first embodiment.

    One end of the pressure reducing pipe (38) is connected to the oil sump container (32) and communicates with a gas space (refrigerant gas space) in the oil sump container (32). The other end of the pressure reducing pipe (38) is connected to the downstream side of the capillary tube (34) in the oil outflow pipe (35) and communicates with the suction side of the compressor (21). The pressure reducing pipe (38) is provided with an on-off valve (36) and a capillary tube (37) in order from the oil reservoir (32) side. The on-off valve (36) is a solenoid valve.

    That is, the surplus oil recovery mechanism (30) of the present embodiment is configured such that the gas refrigerant in the oil reservoir (32) is sucked into the suction pipe of the compressor (21) by opening the on-off valve (36) of the pressure reducing pipe (38). The oil reservoir (32) is depressurized by being sucked into (2b). As a result, the pressure inside the oil separator (22) is almost the same as the discharge pressure of the compressor (21), so that a pressure difference is generated between the oil separator (22) and the oil reservoir (32). . Due to this pressure difference, the refrigerating machine oil in the oil separator (22) flows into the oil reservoir (32) through the oil inflow pipe (31).

    Thus, in this embodiment, the open / close valve (36) of the pressure reducing pipe (38) is not required to introduce the refrigerating machine oil separated by the oil separator (22) into its sump container (32) by its own weight. By opening, the refrigerating machine oil of the oil separator (22) can be reliably recovered in the oil reservoir (32). Therefore, it is not necessary to arrange the oil reservoir (32) below the oil separator (22) as in the first embodiment, and the oil reservoir (32) may be arranged on the side or above the oil separator (22). That is, the degree of freedom of installation of the oil sump container (32) is increased, and the air conditioner (10) can be made compact.

    The controller (40) of the present embodiment performs the following control operation.

    Similarly to the first embodiment, the surplus oil amount calculation unit (41) manually inputs the communication pipe length, and calculates the “surplus oil amount” based on the communication pipe length. On the other hand, the on-off valve controller (42) alternately opens and closes the on-off valve (33) of the oil outflow pipe (35) and the on-off valve (36) of the pressure reducing pipe (38). Specifically, the on-off valve control unit (42) opens the on-off valve (33) of the oil outflow pipe (35) every predetermined time T1 set in advance according to the excess oil amount, as in the first embodiment. To. When the on / off valve control section (42) opens the on / off valve (33) of the oil outflow pipe (35), the on / off valve (36) of the decompression pipe (38) is closed to close the oil outflow pipe (35). When the on-off valve (33) is closed, the on-off valve (36) of the pressure reducing pipe (38) is opened. That is, the on-off valve control unit (42) closes the on-off valve (36) of the pressure reducing pipe (38) every predetermined time T1 set in advance according to the surplus oil amount.

-Driving action-
Next, the operation of the surplus oil recovery mechanism (30) and the control operation of the controller (40) of this embodiment will be described. The refrigerant flow in the cooling operation and the heating operation is the same as that in the first embodiment.

    First, before starting the operation, the on-off valve (33) of the oil outflow pipe (35) is set to the closed state and the on-off valve (36) of the pressure reducing pipe (38) is set to the open state, Manually input to the surplus oil amount calculation unit (41). Then, the surplus oil amount calculation unit (41) calculates the surplus oil amount.

    Next, when the operation is started, the refrigeration oil flows out of the compressor (21) together with the refrigerant, and most of the oil is separated by the oil separator (22). On the other hand, the gas refrigerant in the oil sump container (32) is sucked into the compressor (21) through the pressure reducing pipe (38) and the oil outflow pipe (35). Thereby, the pressure in the oil reservoir (32) is reduced.

    The refrigerating machine oil separated by the oil separator (22) flows into the oil reservoir (32) through the oil inflow pipe (31) due to the pressure difference between the oil separator (22) and the oil reservoir (32). To do. A small amount of refrigeration oil that has not been separated by the oil separator (22) flows through the refrigerant circuit (20) together with the refrigerant. A part of the refrigerating machine oil stays attached to the refrigerant piping and the tubes of the heat exchangers (24, 26), and the rest returns to the compressor (21) together with the refrigerant.

    When a predetermined time T1 has elapsed from the start of operation, the on-off valve controller (42) closes the on-off valve (36) of the pressure reducing pipe (38) and opens the on-off valve (33) of the oil outflow pipe (35). Respectively. During this predetermined time T1, the amount of refrigerating machine oil stored in the oil reservoir (32) increases. Then, when a predetermined time T2 has elapsed after switching each on-off valve (33, 36), the on-off valve control unit (42) again closes the on-off valve (33) of the oil outflow pipe (35) to the pressure reducing pipe. The open / close valve (36) of (38) is switched to the open state. While the on / off valve (33) of the oil outflow pipe (35) is open (during a predetermined time T2), the refrigerating machine oil is supplied from the oil reservoir (32) at a predetermined flow rate to the suction pipe (2b) of the compressor (21). ). At that time, in the oil reservoir (32), the same amount of refrigerating machine oil as that of the refrigerating machine oil flows from the oil separator (22). In this manner, the opening / closing of the on-off valves (33, 36) is repeated. As a result, surplus refrigerating machine oil is always stored in the oil sump container (32).

-Effect of Embodiment 2-
According to the present embodiment, since the pressure reducing pipe (38) is provided in the surplus oil recovery mechanism (30), there is no problem in the positional relationship between the oil separator (22) and the oil reservoir (32), and the oil separator The refrigerating machine oil separated in (22) can be collected in the oil reservoir (32). Therefore, the installation restriction of the oil sump container (32) can be relaxed, and the air conditioner (10) can be made compact.

    Moreover, since the opening / closing timing of the opening / closing valve (36) of the pressure reducing pipe (38) is determined based on the excess oil amount calculated according to the length of the connecting pipe, it is ensured that the oil reservoir (32) has an excess amount. Refrigerating machine oil can be stored. Other configurations, operations, and effects are the same as those in the first embodiment.

<< Embodiment 3 of the Invention >>
Embodiment 3 of the present invention will be described. As shown in FIG. 3, the air conditioner (10) of the present embodiment is provided with a plurality of indoor units (12) (two in this embodiment) in the first embodiment and connected in parallel to each other. Is. Furthermore, the refrigerant circuit (20) of the present embodiment includes an outdoor expansion mechanism (25a) and an indoor expansion mechanism (25b) instead of the expansion mechanism (25) in the first embodiment.

    Specifically, the communication gas pipe (2c) and the communication liquid pipe (2d) extending from the outdoor unit (11) are branched and connected to each indoor unit (12). The outdoor expansion mechanism (25a) is housed in the outdoor unit (11), and is connected between the outdoor heat exchanger (24) and the communication liquid pipe (2d). The indoor expansion mechanism (25b) is housed in each indoor unit (12), and is connected between the indoor heat exchanger (26) and the communication liquid pipe (2d).

    In this case, in the cooling operation, the outdoor expansion mechanism (25a) is set to a fully open state, and the opening degree of each indoor expansion mechanism (25b) is appropriately adjusted. In this cooling operation, after the refrigerant condensed (radiated) in the outdoor heat exchanger (24) is diverted to each indoor unit (12) through the connecting liquid pipe (2d) and depressurized by the indoor expansion mechanism (25b) Evaporates in the indoor heat exchanger (26). In the heating operation, each indoor expansion mechanism (25b) is set to a fully open state, and the opening degree of the outdoor expansion mechanism (25a) is appropriately adjusted. In this heating operation, the refrigerant discharged from the compressor (21) is diverted to each indoor unit (12) through the communication gas pipe (2c), condensed (heat radiation) in the indoor heat exchanger (26), and then connected to the communication liquid. It flows into the pipe (2d). Other driving operations are the same as those in the first embodiment.

    In the controller (40) of the present embodiment, the surplus oil amount calculation unit (41) is manually input the average length of the communication pipe length of each indoor unit (12). The surplus oil amount calculation unit (41) is configured to calculate the “surplus oil amount” based on the input average length. That is, the “actual machine oil amount” corresponding to the average length of the communication pipe length is estimated, and the “surplus oil amount” is calculated.

    In the present embodiment, the length of the connecting pipe for each indoor unit (12) is different, but since the surplus oil amount is calculated based on the average length, the surplus oil amount can be grasped without excess or deficiency. Therefore, surplus refrigeration oil can be reliably recovered in the oil reservoir (32). Other configurations, operations, and effects are the same as those in the first embodiment.

<< Other Embodiments >>
About each said embodiment, it is good also as the following structures.

    For example, in each of the embodiments described above, the time (predetermined time T2) during which the on-off valve (33) of the oil outflow pipe (35) is open is set to a certain time, but is changed according to the calculated surplus oil amount. May be. In this case, the predetermined time T2 is shortened as the excess oil amount increases.

    Moreover, in the said Embodiment 2, although the on-off valve (36) of the pressure reduction pipe | tube (38) was switched to the closed state for every predetermined time T1, you may make it always open.

    In each of the above embodiments, the surplus oil amount is calculated based on the communication pipe length. However, the present invention is not limited to this, and the total length of the communication pipe length and the tube length of each heat exchanger (24, 26). The excess oil amount may be calculated based on the above. In this case, a more appropriate actual machine attached oil amount is estimated, and the surplus oil amount is reliably grasped. Of course, other pipe lengths may be taken into account.

    In addition, when a plurality of indoor units (12) are provided in parallel in the second embodiment, as in the third embodiment, the surplus oil amount is determined based on the average length of the connecting pipe length for each indoor unit (12). What is necessary is just to calculate.

    Moreover, in each said embodiment, although the solenoid valve was used for each on-off valve (33,36), it may replace with this and may use the flow volume adjustment valve which can adjust an opening degree. In that case, the capillary tubes (34, 37) are omitted.

    In each of the above embodiments, the air conditioner has been described. However, the present invention is not limited to this, and the present invention is a refrigeration apparatus (for example, a refrigerator) including a refrigerant circuit having an oil separator connected to the discharge side of the compressor. Etc.) as long as they are applicable.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

    As described above, the present invention is useful as a refrigeration apparatus including a refrigerant circuit in which an oil separator is connected to the discharge side of a compressor.

1 is a piping system diagram illustrating a configuration of an air conditioner according to Embodiment 1. FIG. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on Embodiment 2. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on Embodiment 3.

Explanation of symbols

10 Air conditioning equipment (refrigeration equipment)
11 Outdoor unit (heat source unit)
12 Indoor unit (Usage unit)
20 Refrigerant circuit
21 Compressor
22 Oil separator
24 Outdoor heat exchanger (heat source side heat exchanger)
26 Indoor heat exchanger (use side heat exchanger)
32 Oil sump container
33 On-off valve
35 Oil spill pipe (connection pipe)
36 On-off valve
38 Pressure reducer
40 Controller (control means)
2c Communication gas piping (Communication piping)
2d Communication liquid piping (Communication piping)

Claims (9)

The compressor (21), the oil separator (22) connected to the discharge side of the compressor (21), and the oil separator (22) communicated with and separated by the oil separator (22). An oil reservoir container (32) for storing refrigerating machine oil, the oil reservoir container connected to the oil reservoir container (32) and the suction side of the compressor (21) and having an on-off valve (33) A refrigeration circuit comprising a refrigerant circuit (20) having a connection pipe (35) for returning the refrigeration oil of (32) to the suction side of the compressor (21) and performing a vapor compression refrigeration cycle. apparatus. In claim 1,
While the oil separator (22) and the oil reservoir (32) are connected by a circulation pipe (31) through which the refrigeration oil of the oil separator (22) flows,
The refrigeration apparatus, wherein the oil reservoir (32) is disposed below the oil separator (22). In claim 1,
The oil sump container (32) is filled with a gas refrigerant,
The refrigerant circuit (20) has an on-off valve (36), one end communicates with the gas refrigerant space in the oil reservoir (32), and the other end of the on-off valve (33) in the connection pipe (35). A refrigerating apparatus comprising a pressure reducing pipe (38) connected to the downstream side for reducing the pressure in the oil reservoir (32). In claim 1,
Based on the refrigerant pipe length of the refrigerant circuit (20), the surplus oil amount of the refrigerating machine oil accommodated in the compressor (21) is calculated, and connected at predetermined intervals determined in advance according to the surplus oil amount. A refrigeration apparatus comprising control means (40) for opening an on-off valve (33) of the pipe (35). In claim 3,
Based on the refrigerant pipe length of the refrigerant circuit (20), the surplus oil amount of the refrigerating machine oil accommodated in the compressor (21) is calculated, and every predetermined time predetermined according to the surplus oil amount, A refrigeration apparatus comprising control means (40) for opening the on-off valve (33) of the connecting pipe (35) and closing the on-off valve (36) of the pressure reducing pipe (38). In claim 4 or 5,
The control means (40) estimates the amount of attachment of refrigeration oil to the refrigerant pipe according to the refrigerant pipe length of the refrigerant circuit (20), and is stored in the compressor (21) from the estimated adhesion amount. A refrigerating apparatus configured to calculate an excess oil amount of the refrigerating machine oil. In claim 4 or 5,
The said control means (40) is comprised so that the said predetermined time may be lengthened, so that the calculated excess oil amount is large. In claim 4 or 5,
A heat source unit (11) in which the heat source side heat exchanger (24), the compressor (21), the oil separator (22) and the oil reservoir (32) are housed, and a use side heat exchanger (26) And a usage unit (12) in which
The refrigerant pipe length of the refrigerant circuit (20) is the length of the connecting pipe (2c, 2d) connecting the heat source unit (11) and the utilization unit (12). In claim 8,
A plurality of the usage units (12) are provided and connected in parallel to each other,
The refrigerant pipe length of the refrigerant circuit (20) is an average length of connecting pipes (2c, 2d) connecting the heat source unit (11) and each utilization unit (12).

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