US20120304685A1 - Air conditioner - Google Patents
Air conditioner Download PDFInfo
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- US20120304685A1 US20120304685A1 US13/572,948 US201213572948A US2012304685A1 US 20120304685 A1 US20120304685 A1 US 20120304685A1 US 201213572948 A US201213572948 A US 201213572948A US 2012304685 A1 US2012304685 A1 US 2012304685A1
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- United States
- Prior art keywords
- oil
- pipe
- compressors
- lubricating oil
- compressor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
- F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
- F24F3/065—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units with a plurality of evaporators or condensers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
- F24F1/26—Refrigerant piping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
- F24F1/26—Refrigerant piping
- F24F1/30—Refrigerant piping for use inside the separate outdoor units
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/023—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units
- F25B2313/0233—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple indoor units in parallel arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/025—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units
- F25B2313/0253—Compression machines, plants or systems with reversible cycle not otherwise provided for using multiple outdoor units in parallel arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
- F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
- F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
- F25B2400/07—Details of compressors or related parts
- F25B2400/075—Details of compressors or related parts with parallel compressors
Definitions
- Embodiments described herein relate generally to an air conditioner configuring a refrigerating cycle by an outdoor unit including a plurality of compressors and a plurality of indoor units, and in particular, relates to improvement of an oil return structure to equally store lubricating oil in each compressor.
- An optimal air conditioner for a building including a plurality of air-conditioned locations is known.
- Such a kind of air conditioner includes an oil return circuit that extracts lubricating oil stored in each compressor in which a specified amount of oil or more is stored via an oil balancing pipe and supplies the extracted lubricating oil to compressors with insufficient lubricating oil.
- a gas refrigerant at high temperature/high pressure discharged from each compressor contains oil liquor of lubricating oil and there is a plurality of compressors and thus, the amount of discharged lubricating oil cannot be ignored. Therefore, an oil separator is provided in the refrigerating cycle to separate the oil liquor of lubricating oil contained in a discharged gas. The separated lubricating oil liquor is also returned to each compressor via the oil return circuit.
- the problem is whether lubricating oil can be returned to each compressor equally. Providing an electromagnetic change-over valve in the oil return circuit to avoid an imbalance of the oil amount can be considered, but costs are affected. If a capillary tube is mounted on the oil return circuit for the purpose of detecting the oil level, it is difficult to adapt to changes in operating capacity of the compressor and changes of the number of operating units, leading to differences of the oil return amount.
- the branch unit includes a strainer portion including an inflow port of lubricating oil, a connecting pipe whose one end is connected to an outflow port of the strainer portion, and a distributor connected to the other end of the connecting pipe.
- the distributor has a plurality of outflow paths provided at an end thereof and each outflow path is connected to the outflow port.
- FIG. 1 is a block diagram of a refrigerating cycle of an air conditioner according to an embodiment of the present invention.
- FIG. 2 is a perspective view showing an oil return structure to a compressor according to the embodiment.
- FIG. 3 is a side view showing the structure of a distributor according to the embodiment.
- FIG. 1 is a block diagram of a refrigerating cycle of an air conditioner.
- the air conditioner includes one outdoor unit 1 and a plurality (four in this case) of indoor units 2 A to 2 D.
- the outdoor unit 1 includes a first compressor 3 a , a second compressor 3 b , and a third compressor 3 c as a plurality of compressors.
- Check valves 5 a to 5 c are provided in discharged refrigerant pipes 4 a to 4 c connected to the compressors 3 a to 3 c and further the discharged refrigerant pipes are converged to one refrigerant pipe 6 .
- the first to third compressors 3 a to 3 c are connected in parallel with the refrigerant pipe 6 .
- An oil separator 7 having a function to separate lubricant oil liquor contained in a gas refrigerant, a first port Qa and a second port Qb of a four-way valve 8 , two outdoor heat exchangers 9 a , 9 b connected in parallel, two outdoor expansion valves 10 a , 10 b connected in parallel, a liquid tank 11 , and a first packed valve 12 as a connection portion of a liquid pipe 20 of the outdoor unit 1 are connected to the refrigerant pipe 6 .
- a refrigerant pipe 13 connected to a third port Qc of the four-way valve 8 is connected to a second packed valve 14 to be a connection portion of a gas pipe 21 of the outdoor unit 1 .
- a refrigerant pipe connected to a fourth port Qd of the four-way valve 8 is connected into an accumulator 15 .
- a refrigerant pipe 16 bent into a U-shape inside the accumulator 15 is branched off in three directions before accumulators 17 a to 17 c provided in inlet portions of the first to third compressors 3 a to 3 c before being connected to the respective compressors 3 a to 3 c.
- the refrigerant pipe 16 bent into a U-shape inside the accumulator 15 and extending along the first to third compressors 3 a to 3 c is called a main inlet refrigerant pipe.
- a refrigerant pipe 18 a branched from the main inlet refrigerant pipe 16 and connected to the accumulator 17 a of the first compressor 3 a is called a first inlet refrigerant pipe.
- a refrigerant pipe 18 b branched from the main inlet refrigerant pipe 16 and connected to the accumulator 17 b of the second compressor 3 b is called a second inlet refrigerant pipe and a refrigerant pipe 18 c branched from the main inlet refrigerant pipe 16 and connected to the accumulator 17 c of the third compressor 3 c is called a third inlet refrigerant pipe.
- a refrigerant delivered from the accumulator 15 is drawn into the first to third compressors 3 a to 3 c from the refrigerant pipe 16 via the first to third refrigerant pipes 18 a to 18 c respectively.
- the first compressor 3 a is positioned most upstream and then the second compressor 3 b and the third compressor 3 c are positioned downstream in this order.
- the liquid pipe 20 extending toward the indoor units 2 A to 2 D is connected to the first packed valve 12 .
- the gas pipe 21 extending toward the indoor units 2 A to 2 D is connected to the second packed valve 14 .
- the liquid pipe 20 is split into a plurality of pipes in a terminal portion thereof and the pipes are connected to respective heat exchangers 23 a to 23 d included in the indoor units 2 A to 2 D via expansion valves 24 a to 24 d respectively.
- the gas pipe 21 is also split into a plurality of pipes in a terminal portion thereof and the pipes are connected to respective heat exchangers 23 a to 23 d inside the indoor units 2 A to 2 D.
- the refrigerating cycle of the air conditioner is configured as described above.
- An outdoor fan 25 is arranged opposite to the outdoor heat exchangers 9 a , 9 b included in the outdoor unit 1 and the operation thereof is controlled by an outdoor controller electrically connected to a remote controller (not shown) together with the first to third compressors 3 a to 3 c.
- the outdoor unit 1 includes an inverter, which rectifies the voltage of a commercial AC power supply and converts the rectified voltage to an AC voltage of a frequency in accordance with an instruction of the outdoor controller to output the AC voltage.
- the first to third compressors 3 a to 3 c are variable-capacity types and are each driven by output of the inverter.
- Indoor fans 26 a to 26 d are arranged opposite to the indoor heat exchangers 23 a to 23 d included in the indoor units 2 A to 2 D respectively. These indoor fans 26 a to 26 d are driven and controlled by operating the remote controller.
- the outdoor unit 1 is provided with an oil balancing circuit, which will be described in detail below.
- One end of a first oil balancing pipe 30 a is connected to a predetermined height position on a case side face of the first compressor 3 a and the other end of the first oil balancing pipe 30 a is connected to an oil storage capsule 31 .
- the first oil balancing pipe 30 a is provided with a check valve 32 a and a capillary tube 33 a and a first temperature sensor 34 is provided downstream of the capillary tube 33 a.
- One end of a second oil balancing pipe 30 b is connected to a predetermined height position on the case side face of the second compressor 3 b and the other end of the second oil balancing pipe 30 b is connected to the oil storage capsule 31 .
- the second oil balancing pipe 30 b is provided with a check valve 32 b and a capillary tube 33 b and a second temperature sensor 35 is provided downstream of the capillary tube 33 b.
- One end of a third oil balancing pipe 30 c is connected to a predetermined height position on the case side face of the third compressor 3 c and the other end of the third oil balancing pipe 30 c is connected to the oil storage capsule 31 .
- the third oil balancing pipe 30 c is provided with a check valve 32 c and a capillary tube 33 c and a third temperature sensor 36 is provided downstream of the capillary tube 33 c.
- a bypass pipe 38 branched from the high-pressure side refrigerant pipe 6 is connected to one end of the oil storage capsule 31 and the bypass pipe 38 is provided with a capillary tube and a fourth temperature sensor 39 .
- An oil balancing guide pipe 40 and a balance pipe 41 are connected to the other end of the oil storage capsule 31 .
- the oil balancing guide pipe 40 is connected to the inflow port of a distributor 43 described later via a first electromagnetic opening and closing valve 42 .
- a fifth temperature sensor 44 is provided in the oil balancing guide pipe 40 between the oil storage capsule 31 and the first electromagnetic opening and closing valve 42 .
- the balance pipe 41 is provided with a second electromagnetic opening and closing valve 46 and a check valve 47 and is connected to a balance pipe packed valve 48 .
- the balance pipe packed valve 48 is provided to balance the compressor and the amount of lubricating oil included in each outdoor unit.
- auxiliary bypass pipe 49 One end of an auxiliary bypass pipe 49 is connected to between the check valve 47 and the balance pipe packed valve 48 in the balance pipe 41 .
- the other end of the auxiliary bypass pipe 49 is connected to the main inlet refrigerant pipe 16 between the accumulator and the first refrigerant pipe 18 a and a parallel circuit of a check valve 50 a and a fourth electromagnetic opening and closing valve 50 b is connected to the halfway portion.
- a first oil delivery pipe 51 is connected to the bottom of the oil separator 7 and a second oil deli very pipe 52 is connected to a side portion of the oil separator 7 .
- the first oil delivery pipe 51 is provided with capillary tube and a third electromagnetic opening and closing valve 53 and is connected to between the first electromagnetic opening and closing valve 42 of the oil balancing guide pipe 40 and the distributor 43 .
- the second oil delivery pipe 52 is provided with only a capillary tube and is connected to between the oil storage capsule 31 in the oil balancing guide pipe 40 and the first electromagnetic opening and closing valve 42 .
- the distributor 43 is to be mounted, as will be described later, in a horizontal attitude and an inflow port is opened on one end face and three outflow ports are provided on the other end face. Inside the distributor 43 , a channel connected to the inflow port is split into three channels and each channel is communicatively connected to the outflow port.
- a first outflow port Rf is positioned on an upper left side in a side view of the distributor 43
- a second outflow port Rg is positioned in a lower center
- a third outflow port Rh is positioned on an upper right side.
- the first outflow port Rf and the second outflow port Rh are positioned at substantially the same height.
- a first oil return pipe 55 is connected to the first outflow port Rf and also connected to the first inlet refrigerant pipe 18 a branched from the main inlet refrigerant pipe 16 .
- a second oil return pipe 56 is connected to the second outflow port Rg and also connected to the second inlet refrigerant pipe 18 b branched from the main inlet refrigerant pipe 16 .
- a third oil return pipe 57 is connected to the third outflow port Rh and also connected to the third inlet refrigerant pipe 18 c branched from the main inlet refrigerant pipe 16 .
- An oil reflux cutoff valve 58 as an electromagnetic opening and closing valve is provided, among the three installed compressors 3 a to 3 c , only in the second oil return pipe 56 arranged in the center and connected to the second compressor 3 b.
- the oil balancing circuit is configured as described above.
- FIG. 2 is a perspective view showing an actual pipe structure around the first to third compressors 3 a to 3 c.
- the first compressor 3 a is arranged on the right side in FIG. 2
- the second compressor 3 b is arranged in the center
- the third compressor 3 c is arranged on the left side.
- the compressors 3 a to 3 c are longitudinally mounted, have the discharged refrigerant pipes 4 a to 4 c projecting in respective upper end portions, and have the accumulators 17 a to 17 c provided along the respective side portions.
- a pipe extending along the installation surface from an upper portion of the first compressor 3 a is the main inlet refrigerant pipe 16 connected to the accumulator 15 (not shown) and is provided up to the vicinity of the third compressor 3 c .
- a T-shaped pipe 60 is provided in a region near the first compressor 3 a of the main inlet refrigerant pipe 16 and the first inlet refrigerant pipe 18 a is connected thereto.
- the first inlet refrigerant pipe 18 a is formed by rising along the accumulator 17 a connected to the first compressor 3 a once before being bent into an inverted U-shape. Then, the first inlet refrigerant pipe 18 a is formed in a U-shape after extending to the installation surface and bent into an inverted U-shape again above the accumulator 17 a before being connected to the upper end portion of the accumulator 17 a.
- a T-shaped pipe 61 is provided in a portion near the second compressor 3 b of the main inlet refrigerant pipe 16 and the second inlet refrigerant pipe 18 b is connected thereto.
- the second inlet refrigerant pipe 18 b is also bent in exactly the same manner as the first inlet refrigerant pipe 18 a and connected to the upper end portion of the accumulator 17 b provided along the second compressor 3 b.
- a third inlet refrigerant pipe 19 c is directly formed successively in the terminal portion of the main inlet refrigerant pipe 16 .
- the third inlet refrigerant pie 18 c is also bent in exactly the same manner as the first and second inlet refrigerant pipes 18 a , 18 b . Then, the third inlet refrigerant pipe 18 c is connected to the upper end portion of the accumulator 17 c provided along the third compressor 3 c.
- the distributor 43 is mounted in a portion of the main inlet refrigerant pipe 16 in the horizontal attitude as a region provided along the installation surface of each of the compressors 3 a to 3 c in the main inlet refrigerant pipe 16 . That is, the distributor 43 is mounted along a horizontal region of the main inlet refrigerant pipe 16 and thus takes up a horizontal attitude.
- the oil balancing guide pipe 40 extending from the oil storage capsule 31 is connected to the left-side portion of the distributor 43 in FIG. 2 .
- One pipe in the upper portion, the first oil return pipe 55 is formed along a horizontal portion of the main inlet refrigerant pipe 16 once and then by rising along the first inlet refrigerant pipe 18 a and is connected to a halfway portion thereof.
- the pipe in the lower portion, the second oil return pipe 56 is formed along the horizontal portion of the main inlet refrigerant pipe 16 once and then by rising along the second inlet refrigerant pipe 18 b.
- the second oil return pipe 56 is bent into the horizontal direction at substantially the same height as a region where the second inlet refrigerant pipe 18 b is bent into an inverted U-shape before being connected to the oil reflux cutoff valve 58 .
- FIG. 2 only the valve element of the oil reflux cutoff valve 58 is shown and an electromagnetic coil portion is omitted.
- the second oil return pipe 56 coming out of the oil reflux cutoff valve 58 is fixed to the second inlet refrigerant pipe 18 b via a pipe fixture 62 and connected to the second inlet refrigerant pipe 18 b in a lower region.
- the other pipe in the upper portion of the distributor 43 , the third oil return pipe 57 is bent in order to be parallel to the oil balancing guide pipe 40 before being connected to a rising portion of the third inlet refrigerant pipe 18 c.
- the gas refrigerant from the oil separator 7 is led into the four-way valve 8 and then, during cooling operation, led into the outdoor heat exchangers 9 a , 9 b for heat exchange with an outdoor air.
- the gas refrigerant is condensed to a liquid to change into a liquid refrigerant before being led into each of the indoor units 2 A to 2 D via the outdoor expansion valves ( 10 a , 10 b ), the liquid tank 11 , the first packed valve 12 , and the liquid pipe 20 sequentially.
- the liquid refrigerant is adiabatically expanded by the expansion valves 24 a to 24 d before flowing into the indoor heat exchangers 23 a to 23 d , where the liquid refrigerant exchanges heat with an indoor air in the respective indoor heat exchangers 23 a to 23 d before being evaporated.
- the indoor air is deprived of evaporative latent heat to change the indoor air into a cold air.
- a cold air is blown indoors by the action of the indoor fans 26 a to 26 d to achieve a cooling operation.
- An evaporative refrigerant delivered from the indoor heat exchangers 23 a to 23 d comes out of the indoor units 2 A to 2 D and then is led into the outdoor unit 1 from the gas pipe 21 and the second packed valve 14 .
- the evaporative refrigerant is led from the four-way valve 8 into the accumulator 15 for vapor-liquid separation and then split into the first to third inlet refrigerant pipes 18 a to 18 c from the from the main inlet refrigerant pipe 16 .
- the evaporative refrigerant is drawn into the first to third compressors 3 a to 3 c from the first to third inlet refrigerant pipes 18 a to 18 c via the accumulators 17 a to 17 c .
- the evaporative refrigerant is compressed in each of the compressors 3 a to 3 c to become a gas refrigerant at high temperature/high pressure before circulating through the above path again.
- the refrigerant during heating operation is led in the direction opposite to the direction during cooling operation by switching the four-way valve 8 .
- the refrigerant is condensed in the indoor heat exchangers 23 a to 23 d of the indoor units 2 A to 2 D to give off heat to an indoor air.
- the indoor air changes to a warm air and is blown indoors to achieve an indoor warming operation.
- Lubricating oil is stored in each sealed case of the first to third compressors 3 a to 3 c and the oil level height may be higher than the connection position of the first to third oil balancing pipes 30 a to 30 c connected to the respective side portions.
- Lubricating oil for the portion exceeding the connection position of the first to third oil balancing pipes 30 a to 30 c is delivered to the first to third oil balancing pipes 30 a to 30 c as surplus lubricating oil. Then, the lubricating oil is led to the oil storage capsule 31 via the capillary tubes 33 a to 33 c.
- the lubricating oil flowing into the oil storage capsule 31 is led into the oil balancing guide pipe 40 by pressure applied from the bypass pipe 38 via a capillary tube.
- the first electromagnetic opening and closing valve 42 provided in the oil balancing guide pipe 40 is normally controlled to open and the lubricating oil flowing out of the oil storage capsule 31 is guided into the distributor 43 .
- the lubricating oil is led to channels split into three directions from the inflow port before flowing out from the respective outflow ports.
- the lubricating oil is equally split into the first to third oil return pipes 55 to 57 . Then, the lubricating oil is led from the first to third oil return pipes 55 to 57 into the first to third inlet refrigerant pipes 18 to 18 c respectively. Particularly, the lubricating oil led into the second oil return pipe 56 is circulated through the oil reflux cutoff valve 58 controlled to be open.
- the lubricating oil having flown into the first to third inlet refrigerant pipes 18 a to 18 c circulates through the refrigerating cycle and is drawn into the first to third compressors 3 a to 3 c together with the evaporative refrigerant delivered from the accumulator 15 .
- the oil level height of the first compressor 3 a may be higher than the connection position of the first oil balancing pipe 30 a
- the oil level height of the second compressor 3 b may be lower than the connection position of the second oil balancing pipe 30 b
- the oil level height of the third compressor 3 c may be in the connection position of the third oil balancing pipe 30 c . That is, the oil levels of the first to third compressors 3 a to 3 c may be imbalanced.
- lubricating oil flows into the first oil balancing pipe 30 a connected to the first compressor 3 a and a gas refrigerant at high pressure flows into the second oil balancing pipe 30 b connected to the second compressor 3 b .
- the lubricating oil and the gas refrigerant having flown into the oil balancing pipes 30 a , 30 b are gathered in the oil storage capsule 31 and flow out in a mixed state to be led into the oil balancing guide pipe 40 .
- the lubricating oil and the gas refrigerant flow from the oil balancing guide pipe 40 into the distributor 43 and equally split into three channels.
- the lubricating oil and the gas refrigerant are led from the distributor 43 into the first to third compressors 3 a to 3 c via the first to third oil return pipes 55 to 57 and the first to third inlet refrigerant pipes 18 a to 18 c.
- lubricating oil moves from a compressor with a large amount of lubricating oil, for example, the first compressor 3 a to a compressor with a small amount of lubricating oil, for example, the second compressor 3 b .
- the oil levels of the first to third compressors 3 a to 3 c are quickly balanced.
- a gas refrigerant discharged from the first to third compressors 3 a to 3 c contains a portion of lubricating oil stored in each of the compressors.
- Such a mixed fluid is discharged into the discharged refrigerant pipes 4 a to 4 c and then led from the high-pressure side refrigerant pipe 6 to the oil separator 7 .
- oil separator 7 lubricating oil liquor is separated from the gas refrigerant.
- the third electromagnetic opening and closing valve 53 is provided in the first oil delivery pipe 51 connected to the bottom of the oil separator 7 and the third electromagnetic opening and closing valve 53 is normally in a closed state.
- the lubricating oil liquor separated here is once stored in the oil separator 7 and only a gas refrigerant is led into the four-way valve 8 .
- the lubricating oil stored in the oil separator 7 increases and at last rises to the connection position of the second oil delivery pipe 52 connected to the side portion thereof. Te lubricating oil for a portion exceeding the connection position of the second oil delivery pipe 52 flows from the oil delivery pipe 52 into the oil balancing guide pipe 40 before being returned, as described above, to the first to third compressors 3 a to 3 c via the distributor 43 and the first to third oil return pipes 55 to 57 .
- an opening signal is issued to the third electromagnetic opening and closing valve 53 provided in the first oil delivery pipe 51 at the bottom of the oil separator 7 and also a closing signal is issued to the first electromagnetic opening and closing valve 42 in the oil balancing guide pipe 40 .
- All lubricating oil stored in the oil separator 7 is led from the first oil delivery pipe 51 into the oil balancing guide pipe 40 and drawn into the first to third compressors 3 a to 3 c via the distributor 43 , the first to third oil return pipes 55 to 57 , the main inlet refrigerant pipe 16 , and the first to third inlet refrigerant pipes 18 a to 18 c before being equally distributed among these compressors 3 a to 3 c.
- the distributor 43 for oil return is mounted on a horizontal portion of the main inlet refrigerant pipe 16 connected to the compressors 3 a to 3 c via the pipe fixture 62 to take up a horizontal attitude.
- the secondary side pipe on the distribution side of the distributor 43 is connected to the first to third inlet refrigerant pipes 18 a to 18 c and thus is provided in a position very close to the first to third compressors 3 a to 3 c.
- vibrations of the first to third compressors 3 a to 3 c being driven are more likely to be propagated to the distributor 43 via the first to third inlet refrigerant pipes 18 a to 18 c and the main inlet refrigerant pipe 16 .
- the same vibration system is created by mounting and fixing the distributor 43 in a horizontal attitude to the main inlet refrigerant pipe 16 so that a pipe fatigue fracture can be prevented.
- the distributor 43 in a horizontal attitude is mounted and fixed to the main inlet refrigerant pipe 16 and thus, no time and effort is needed for the control so that it becomes possible to reduce product variations and cut production costs.
- the outdoor unit 1 including a plurality of compressors, operating compressors and non-operating compressors may be mixed. In such an operation condition, the ratio of lubricating oil flowing back via the oil balancing circuit may not be equal.
- the first compressor 3 a and the second compressor 3 b are operating and the third compressor is non-operating.
- the amount of lubricating oil returned from the distributor 43 to the first compressor 3 a via the first oil return pipe 55 and the amount of lubricating oil returned to the second compressor 3 b via the second oil return pipe 56 are the same.
- the distributor 43 includes three channels for one inflow port and is configured so that the lubricating oil flows equally through these channels. Naturally, the same amount of lubricating oil is led from the distributor 43 to the third oil return pipe 57 to move to the third compressor 3 c.
- the third compressor 3 c is non-operating and thus, the lubricating oil flowing from the third oil return pipe 57 into the third inlet refrigerant pipe 18 c is not drawn into the third compressor 3 c .
- the lubricating oil has nowhere to go and flows from the third inlet refrigerant pipe 18 c into the main inlet refrigerant pipe 16 .
- the ratio of the amounts of lubricating oil flowing back into the first compressor 3 a and flowing back into the second compressor 3 b becomes 1:2 and while too much lubricating oil is stored in the second compressor 3 b , the lubricating oil is insufficient in the first compressor 3 a.
- the second oil return pipe 3 b includes the oil reflux cutoff valve 58 and is controlled to close the oil reflux cutoff valve 58 in the above situation. From the above, lubricating oil is led from the distributor 43 to the first oil return pipe 55 and the third oil return pipe 57 , but does not flow to the second oil return pipe 56 .
- the lubricating oil flows back from the first oil return pipe 55 to the first compressor 3 a and the lubricating oil flows back from the third oil return pipe 57 to the second compressor 3 b . No lubricating oil flows back unchangingly to the non-operating compressor 3 C.
- the second oil return pipe 56 communicatively connected to the middle compressor 3 b of three compressors includes the oil reflux cutoff valve 58 , which is controlled to close in the above situation.
- the first outflow port Rf and the third outflow port Rh of the distributor 43 are positioned at substantially the same height and thus, substantially the same amount of lubricating oil flows into the first oil return pipe 55 and the third oil return pipe 57 . That is, the same amount of lubricating oil flows back to the first compressor 3 a and the second compressor 3 b so that lubricating oil is mutually in proper quantities.
- the amount of lubricating oil held in operating compressors can be adjusted by controlling the oil reflux cutoff valve 58 to open or close.
- the second compressor 3 b may run out of oil while the oil reflux cutoff valve 58 is closed.
- the lack of oil can be known by comparing detected temperatures of the fourth temperature sensor 39 provided in the bypass pipe 38 and first to third temperature sensors 35 to 37 provided in the first to third oil balancing pipes 30 a to 30 c.
- the oil reflux cutoff valve 58 is controlled to open.
- the second outflow port Rg of the distributor 43 is, among three outflow ports, in the lowest position and thus, more lubricating oil flows into the second oil return pipe 56 connected to the second outflow port Rg than into the oil return pipes 55 , 57 . Therefore, the amount of lubricating oil returning from the second oil return pipe 56 to the second compressor 3 b increases to balance the amounts of lubricating oil held by the first compressor 3 a and the second compressor 3 b.
- the present invention is not limited to the above embodiment as it is and can be embodied by modifying structural elements without deviating from the scope thereof in the time of the working. Then, various inventions can be formed by appropriately combining a plurality of structural elements disclosed in the above embodiment.
- an air conditioner achieving effects such as being easy and reliable to fix a distributor to reduce production variations and being able to prevent a pipe fatigue fracture accompanying a compressor being driven.
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Abstract
An air conditioner includes oil balancing pipes that extract lubricating oil stored in an oil separator and each of compressors in which a specified amount of the lubricating oil or more is stored, a distributor that distributes the lubricating oil led from the oil separator and the compressors to a plurality of channels, and oil return pipes that communicatively connect the distribution channels of the distributor and a refrigerant inlet pipe of each of the compressors to return the lubricating oil to each of the compressors.
Description
- This application is a Continuation Application of PCT Application No. PCT/JP2011/03165, filed Feb. 15, 2011 and based upon and claiming the benefit of priority from Japanese Patent Application No. 2010-030526, filed Feb. 15, 2010, the entire contents of all of which are incorporated herein by reference.
- Embodiments described herein relate generally to an air conditioner configuring a refrigerating cycle by an outdoor unit including a plurality of compressors and a plurality of indoor units, and in particular, relates to improvement of an oil return structure to equally store lubricating oil in each compressor.
- An optimal air conditioner for a building including a plurality of air-conditioned locations is known. Such a kind of air conditioner includes an oil return circuit that extracts lubricating oil stored in each compressor in which a specified amount of oil or more is stored via an oil balancing pipe and supplies the extracted lubricating oil to compressors with insufficient lubricating oil.
- A gas refrigerant at high temperature/high pressure discharged from each compressor contains oil liquor of lubricating oil and there is a plurality of compressors and thus, the amount of discharged lubricating oil cannot be ignored. Therefore, an oil separator is provided in the refrigerating cycle to separate the oil liquor of lubricating oil contained in a discharged gas. The separated lubricating oil liquor is also returned to each compressor via the oil return circuit.
- The problem is whether lubricating oil can be returned to each compressor equally. Providing an electromagnetic change-over valve in the oil return circuit to avoid an imbalance of the oil amount can be considered, but costs are affected. If a capillary tube is mounted on the oil return circuit for the purpose of detecting the oil level, it is difficult to adapt to changes in operating capacity of the compressor and changes of the number of operating units, leading to differences of the oil return amount.
- For example, an example using a branch unit capable of distributing in three directions in place of a T cube as a branch pipe connected to three compressors to distribute lubricating oil for oil return is disclosed (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2006-112668).
- More specifically, the branch unit includes a strainer portion including an inflow port of lubricating oil, a connecting pipe whose one end is connected to an outflow port of the strainer portion, and a distributor connected to the other end of the connecting pipe. The distributor has a plurality of outflow paths provided at an end thereof and each outflow path is connected to the outflow port.
-
FIG. 1 is a block diagram of a refrigerating cycle of an air conditioner according to an embodiment of the present invention. -
FIG. 2 is a perspective view showing an oil return structure to a compressor according to the embodiment. -
FIG. 3 is a side view showing the structure of a distributor according to the embodiment. - An embodiment of the present invention will be described based on the drawings.
-
FIG. 1 is a block diagram of a refrigerating cycle of an air conditioner. - The air conditioner includes one
outdoor unit 1 and a plurality (four in this case) ofindoor units 2A to 2D. - The
outdoor unit 1 includes afirst compressor 3 a, asecond compressor 3 b, and a third compressor 3 c as a plurality of compressors.Check valves 5 a to 5 c are provided in dischargedrefrigerant pipes 4 a to 4 c connected to thecompressors 3 a to 3 c and further the discharged refrigerant pipes are converged to one refrigerant pipe 6. In other words, the first tothird compressors 3 a to 3 c are connected in parallel with the refrigerant pipe 6. - An
oil separator 7 having a function to separate lubricant oil liquor contained in a gas refrigerant, a first port Qa and a second port Qb of a four-way valve 8, twooutdoor heat exchangers outdoor expansion valves liquid tank 11, and a first packedvalve 12 as a connection portion of aliquid pipe 20 of theoutdoor unit 1 are connected to the refrigerant pipe 6. Arefrigerant pipe 13 connected to a third port Qc of the four-way valve 8 is connected to a second packedvalve 14 to be a connection portion of agas pipe 21 of theoutdoor unit 1. A refrigerant pipe connected to a fourth port Qd of the four-way valve 8 is connected into anaccumulator 15. - A
refrigerant pipe 16 bent into a U-shape inside theaccumulator 15 is branched off in three directions beforeaccumulators 17 a to 17 c provided in inlet portions of the first tothird compressors 3 a to 3 c before being connected to therespective compressors 3 a to 3 c. - Particularly, the
refrigerant pipe 16 bent into a U-shape inside theaccumulator 15 and extending along the first tothird compressors 3 a to 3 c is called a main inlet refrigerant pipe. Arefrigerant pipe 18 a branched from the maininlet refrigerant pipe 16 and connected to theaccumulator 17 a of thefirst compressor 3 a is called a first inlet refrigerant pipe. - Similarly, a refrigerant pipe 18 b branched from the main
inlet refrigerant pipe 16 and connected to theaccumulator 17 b of thesecond compressor 3 b is called a second inlet refrigerant pipe and arefrigerant pipe 18 c branched from the maininlet refrigerant pipe 16 and connected to theaccumulator 17 c of the third compressor 3 c is called a third inlet refrigerant pipe. - As will be described later, a refrigerant delivered from the
accumulator 15 is drawn into the first tothird compressors 3 a to 3 c from therefrigerant pipe 16 via the first tothird refrigerant pipes 18 a to 18 c respectively. Thus, thefirst compressor 3 a is positioned most upstream and then thesecond compressor 3 b and the third compressor 3 c are positioned downstream in this order. - The
liquid pipe 20 extending toward theindoor units 2A to 2D is connected to the first packedvalve 12. Similarly, thegas pipe 21 extending toward theindoor units 2A to 2D is connected to the second packedvalve 14. - The
liquid pipe 20 is split into a plurality of pipes in a terminal portion thereof and the pipes are connected torespective heat exchangers 23 a to 23 d included in theindoor units 2A to 2D viaexpansion valves 24 a to 24 d respectively. Thegas pipe 21 is also split into a plurality of pipes in a terminal portion thereof and the pipes are connected torespective heat exchangers 23 a to 23 d inside theindoor units 2A to 2D. - The refrigerating cycle of the air conditioner is configured as described above.
- An
outdoor fan 25 is arranged opposite to theoutdoor heat exchangers outdoor unit 1 and the operation thereof is controlled by an outdoor controller electrically connected to a remote controller (not shown) together with the first tothird compressors 3 a to 3 c. - The
outdoor unit 1 includes an inverter, which rectifies the voltage of a commercial AC power supply and converts the rectified voltage to an AC voltage of a frequency in accordance with an instruction of the outdoor controller to output the AC voltage. The first tothird compressors 3 a to 3 c are variable-capacity types and are each driven by output of the inverter. -
Indoor fans 26 a to 26 d are arranged opposite to theindoor heat exchangers 23 a to 23 d included in theindoor units 2A to 2D respectively. Theseindoor fans 26 a to 26 d are driven and controlled by operating the remote controller. - Further, the
outdoor unit 1 is provided with an oil balancing circuit, which will be described in detail below. - One end of a first
oil balancing pipe 30 a is connected to a predetermined height position on a case side face of thefirst compressor 3 a and the other end of the firstoil balancing pipe 30 a is connected to an oil storage capsule 31. The firstoil balancing pipe 30 a is provided with acheck valve 32 a and acapillary tube 33 a and afirst temperature sensor 34 is provided downstream of thecapillary tube 33 a. - One end of a second oil balancing pipe 30 b is connected to a predetermined height position on the case side face of the
second compressor 3 b and the other end of the second oil balancing pipe 30 b is connected to the oil storage capsule 31. The second oil balancing pipe 30 b is provided with acheck valve 32 b and a capillary tube 33 b and a second temperature sensor 35 is provided downstream of the capillary tube 33 b. - One end of a third oil balancing pipe 30 c is connected to a predetermined height position on the case side face of the third compressor 3 c and the other end of the third oil balancing pipe 30 c is connected to the oil storage capsule 31. The third oil balancing pipe 30 c is provided with a
check valve 32 c and a capillary tube 33 c and a third temperature sensor 36 is provided downstream of the capillary tube 33 c. - A
bypass pipe 38 branched from the high-pressure side refrigerant pipe 6 is connected to one end of the oil storage capsule 31 and thebypass pipe 38 is provided with a capillary tube and afourth temperature sensor 39. An oilbalancing guide pipe 40 and abalance pipe 41 are connected to the other end of the oil storage capsule 31. - The oil
balancing guide pipe 40 is connected to the inflow port of adistributor 43 described later via a first electromagnetic opening and closing valve 42. Afifth temperature sensor 44 is provided in the oilbalancing guide pipe 40 between the oil storage capsule 31 and the first electromagnetic opening and closing valve 42. - The
balance pipe 41 is provided with a second electromagnetic opening and closing valve 46 and acheck valve 47 and is connected to a balance pipe packedvalve 48. When a plurality of outdoor units is connected in parallel, the balance pipe packedvalve 48 is provided to balance the compressor and the amount of lubricating oil included in each outdoor unit. - One end of an
auxiliary bypass pipe 49 is connected to between thecheck valve 47 and the balance pipe packedvalve 48 in thebalance pipe 41. The other end of theauxiliary bypass pipe 49 is connected to the maininlet refrigerant pipe 16 between the accumulator and thefirst refrigerant pipe 18 a and a parallel circuit of acheck valve 50 a and a fourth electromagnetic opening andclosing valve 50 b is connected to the halfway portion. - On the other hand, a first
oil delivery pipe 51 is connected to the bottom of theoil separator 7 and a second oil deli verypipe 52 is connected to a side portion of theoil separator 7. - The first
oil delivery pipe 51 is provided with capillary tube and a third electromagnetic opening and closingvalve 53 and is connected to between the first electromagnetic opening and closing valve 42 of the oil balancingguide pipe 40 and thedistributor 43. The secondoil delivery pipe 52 is provided with only a capillary tube and is connected to between the oil storage capsule 31 in the oil balancingguide pipe 40 and the first electromagnetic opening and closing valve 42. - The
distributor 43 is to be mounted, as will be described later, in a horizontal attitude and an inflow port is opened on one end face and three outflow ports are provided on the other end face. Inside thedistributor 43, a channel connected to the inflow port is split into three channels and each channel is communicatively connected to the outflow port. - As shown in
FIG. 3 , a first outflow port Rf is positioned on an upper left side in a side view of thedistributor 43, a second outflow port Rg is positioned in a lower center, and a third outflow port Rh is positioned on an upper right side. The first outflow port Rf and the second outflow port Rh are positioned at substantially the same height. - A first
oil return pipe 55 is connected to the first outflow port Rf and also connected to the firstinlet refrigerant pipe 18 a branched from the maininlet refrigerant pipe 16. A secondoil return pipe 56 is connected to the second outflow port Rg and also connected to the second inlet refrigerant pipe 18 b branched from the maininlet refrigerant pipe 16. - A third
oil return pipe 57 is connected to the third outflow port Rh and also connected to the thirdinlet refrigerant pipe 18 c branched from the maininlet refrigerant pipe 16. An oilreflux cutoff valve 58 as an electromagnetic opening and closing valve is provided, among the threeinstalled compressors 3 a to 3 c, only in the secondoil return pipe 56 arranged in the center and connected to thesecond compressor 3 b. - The oil balancing circuit is configured as described above.
-
FIG. 2 is a perspective view showing an actual pipe structure around the first tothird compressors 3 a to 3 c. - The
first compressor 3 a is arranged on the right side inFIG. 2 , thesecond compressor 3 b is arranged in the center, and the third compressor 3 c is arranged on the left side. Thecompressors 3 a to 3 c are longitudinally mounted, have the dischargedrefrigerant pipes 4 a to 4 c projecting in respective upper end portions, and have theaccumulators 17 a to 17 c provided along the respective side portions. - A pipe extending along the installation surface from an upper portion of the
first compressor 3 a is the maininlet refrigerant pipe 16 connected to the accumulator 15 (not shown) and is provided up to the vicinity of the third compressor 3 c. A T-shapedpipe 60 is provided in a region near thefirst compressor 3 a of the maininlet refrigerant pipe 16 and the firstinlet refrigerant pipe 18 a is connected thereto. - The first
inlet refrigerant pipe 18 a is formed by rising along theaccumulator 17 a connected to thefirst compressor 3 a once before being bent into an inverted U-shape. Then, the firstinlet refrigerant pipe 18 a is formed in a U-shape after extending to the installation surface and bent into an inverted U-shape again above theaccumulator 17 a before being connected to the upper end portion of theaccumulator 17 a. - Also, a T-shaped
pipe 61 is provided in a portion near thesecond compressor 3 b of the maininlet refrigerant pipe 16 and the second inlet refrigerant pipe 18 b is connected thereto. The second inlet refrigerant pipe 18 b is also bent in exactly the same manner as the firstinlet refrigerant pipe 18 a and connected to the upper end portion of theaccumulator 17 b provided along thesecond compressor 3 b. - A third inlet refrigerant pipe 19 c is directly formed successively in the terminal portion of the main
inlet refrigerant pipe 16. The thirdinlet refrigerant pie 18 c is also bent in exactly the same manner as the first and secondinlet refrigerant pipes 18 a, 18 b. Then, the thirdinlet refrigerant pipe 18 c is connected to the upper end portion of theaccumulator 17 c provided along the third compressor 3 c. - On the other hand, the
distributor 43 is mounted in a portion of the maininlet refrigerant pipe 16 in the horizontal attitude as a region provided along the installation surface of each of thecompressors 3 a to 3 c in the maininlet refrigerant pipe 16. That is, thedistributor 43 is mounted along a horizontal region of the maininlet refrigerant pipe 16 and thus takes up a horizontal attitude. - The oil balancing
guide pipe 40 extending from the oil storage capsule 31 (not shown) is connected to the left-side portion of thedistributor 43 inFIG. 2 . A total of threeoil return pipes - One pipe in the upper portion, the first
oil return pipe 55, is formed along a horizontal portion of the maininlet refrigerant pipe 16 once and then by rising along the firstinlet refrigerant pipe 18 a and is connected to a halfway portion thereof. The pipe in the lower portion, the secondoil return pipe 56, is formed along the horizontal portion of the maininlet refrigerant pipe 16 once and then by rising along the second inlet refrigerant pipe 18 b. - Then, the second
oil return pipe 56 is bent into the horizontal direction at substantially the same height as a region where the second inlet refrigerant pipe 18 b is bent into an inverted U-shape before being connected to the oilreflux cutoff valve 58. InFIG. 2 , only the valve element of the oilreflux cutoff valve 58 is shown and an electromagnetic coil portion is omitted. - The second
oil return pipe 56 coming out of the oilreflux cutoff valve 58 is fixed to the second inlet refrigerant pipe 18 b via apipe fixture 62 and connected to the second inlet refrigerant pipe 18 b in a lower region. The other pipe in the upper portion of thedistributor 43, the thirdoil return pipe 57, is bent in order to be parallel to the oil balancingguide pipe 40 before being connected to a rising portion of the thirdinlet refrigerant pipe 18 c. - Next, the flow of the refrigerant in a refrigerating cycle circuit will be described.
- When the first to
third compressors 3 a to 3 c are driven, a gas refrigerant at high temperature/high pressure discharged from each of the first tothird compressors 3 a to 3 c is led into the refrigerant pipe 6 via the dischargedrefrigerant pipes 4 a to 4 c connected respectively. Then, the refrigerant pipe 6 supplies the gas refrigerant to theoil separator 7 where lubricating oil liquor contained in the gas refrigerant is separated. - The gas refrigerant from the
oil separator 7 is led into the four-way valve 8 and then, during cooling operation, led into theoutdoor heat exchangers indoor units 2A to 2D via the outdoor expansion valves (10 a, 10 b), theliquid tank 11, the first packedvalve 12, and theliquid pipe 20 sequentially. - In the
indoor units 2A to 2D, the liquid refrigerant is adiabatically expanded by theexpansion valves 24 a to 24 d before flowing into theindoor heat exchangers 23 a to 23 d, where the liquid refrigerant exchanges heat with an indoor air in the respectiveindoor heat exchangers 23 a to 23 d before being evaporated. At this point, the indoor air is deprived of evaporative latent heat to change the indoor air into a cold air. A cold air is blown indoors by the action of theindoor fans 26 a to 26 d to achieve a cooling operation. - An evaporative refrigerant delivered from the
indoor heat exchangers 23 a to 23 d comes out of theindoor units 2A to 2D and then is led into theoutdoor unit 1 from thegas pipe 21 and the second packedvalve 14. In theoutdoor unit 1, the evaporative refrigerant is led from the four-way valve 8 into theaccumulator 15 for vapor-liquid separation and then split into the first to third inletrefrigerant pipes 18 a to 18 c from the from the maininlet refrigerant pipe 16. - The evaporative refrigerant is drawn into the first to
third compressors 3 a to 3 c from the first to third inletrefrigerant pipes 18 a to 18 c via theaccumulators 17 a to 17 c. The evaporative refrigerant is compressed in each of thecompressors 3 a to 3 c to become a gas refrigerant at high temperature/high pressure before circulating through the above path again. - The refrigerant during heating operation is led in the direction opposite to the direction during cooling operation by switching the four-
way valve 8. The refrigerant is condensed in theindoor heat exchangers 23 a to 23 d of theindoor units 2A to 2D to give off heat to an indoor air. The indoor air changes to a warm air and is blown indoors to achieve an indoor warming operation. - Next, the flow of lubricating oil in the oil balancing circuit will be described.
- Lubricating oil is stored in each sealed case of the first to
third compressors 3 a to 3 c and the oil level height may be higher than the connection position of the first to thirdoil balancing pipes 30 a to 30 c connected to the respective side portions. - Lubricating oil for the portion exceeding the connection position of the first to third
oil balancing pipes 30 a to 30 c is delivered to the first to thirdoil balancing pipes 30 a to 30 c as surplus lubricating oil. Then, the lubricating oil is led to the oil storage capsule 31 via thecapillary tubes 33 a to 33 c. - A small amount of gas refrigerant at high pressure split from the high-pressure side refrigerant pipe 6 into the
bypass pipe 38 flows into the oil storage capsule 31. The lubricating oil flowing into the oil storage capsule 31 is led into the oil balancingguide pipe 40 by pressure applied from thebypass pipe 38 via a capillary tube. - The first electromagnetic opening and closing valve 42 provided in the oil balancing
guide pipe 40 is normally controlled to open and the lubricating oil flowing out of the oil storage capsule 31 is guided into thedistributor 43. In thedistributor 43, the lubricating oil is led to channels split into three directions from the inflow port before flowing out from the respective outflow ports. - That is, in the
distributor 43, the lubricating oil is equally split into the first to thirdoil return pipes 55 to 57. Then, the lubricating oil is led from the first to thirdoil return pipes 55 to 57 into the first to third inlet refrigerant pipes 18 to 18 c respectively. Particularly, the lubricating oil led into the secondoil return pipe 56 is circulated through the oilreflux cutoff valve 58 controlled to be open. - The lubricating oil having flown into the first to third inlet
refrigerant pipes 18 a to 18 c circulates through the refrigerating cycle and is drawn into the first tothird compressors 3 a to 3 c together with the evaporative refrigerant delivered from theaccumulator 15. - For example, the oil level height of the
first compressor 3 a may be higher than the connection position of the firstoil balancing pipe 30 a, the oil level height of thesecond compressor 3 b may be lower than the connection position of the second oil balancing pipe 30 b, and the oil level height of the third compressor 3 c may be in the connection position of the third oil balancing pipe 30 c. That is, the oil levels of the first tothird compressors 3 a to 3 c may be imbalanced. - In such a case, lubricating oil flows into the first
oil balancing pipe 30 a connected to thefirst compressor 3 a and a gas refrigerant at high pressure flows into the second oil balancing pipe 30 b connected to thesecond compressor 3 b. The lubricating oil and the gas refrigerant having flown into theoil balancing pipes 30 a, 30 b are gathered in the oil storage capsule 31 and flow out in a mixed state to be led into the oil balancingguide pipe 40. - Then, the lubricating oil and the gas refrigerant flow from the oil balancing
guide pipe 40 into thedistributor 43 and equally split into three channels. The lubricating oil and the gas refrigerant are led from thedistributor 43 into the first tothird compressors 3 a to 3 c via the first to thirdoil return pipes 55 to 57 and the first to third inletrefrigerant pipes 18 a to 18 c. - In this manner, lubricating oil moves from a compressor with a large amount of lubricating oil, for example, the
first compressor 3 a to a compressor with a small amount of lubricating oil, for example, thesecond compressor 3 b. Thus, the oil levels of the first tothird compressors 3 a to 3 c are quickly balanced. - On the other hand, a gas refrigerant discharged from the first to
third compressors 3 a to 3 c contains a portion of lubricating oil stored in each of the compressors. Such a mixed fluid is discharged into the dischargedrefrigerant pipes 4 a to 4 c and then led from the high-pressure side refrigerant pipe 6 to theoil separator 7. In theoil separator 7, lubricating oil liquor is separated from the gas refrigerant. - The third electromagnetic opening and closing
valve 53 is provided in the firstoil delivery pipe 51 connected to the bottom of theoil separator 7 and the third electromagnetic opening and closingvalve 53 is normally in a closed state. Thus, the lubricating oil liquor separated here is once stored in theoil separator 7 and only a gas refrigerant is led into the four-way valve 8. - The lubricating oil stored in the
oil separator 7 increases and at last rises to the connection position of the secondoil delivery pipe 52 connected to the side portion thereof. Te lubricating oil for a portion exceeding the connection position of the secondoil delivery pipe 52 flows from theoil delivery pipe 52 into the oil balancingguide pipe 40 before being returned, as described above, to the first tothird compressors 3 a to 3 c via thedistributor 43 and the first to thirdoil return pipes 55 to 57. - For some reason or other, the oil levels in the sealed cases of all the
compressors 3 a to 3 c may fall at the same time. In such a case, an opening signal is issued to the third electromagnetic opening and closingvalve 53 provided in the firstoil delivery pipe 51 at the bottom of theoil separator 7 and also a closing signal is issued to the first electromagnetic opening and closing valve 42 in the oil balancingguide pipe 40. - All lubricating oil stored in the
oil separator 7 is led from the firstoil delivery pipe 51 into the oil balancingguide pipe 40 and drawn into the first tothird compressors 3 a to 3 c via thedistributor 43, the first to thirdoil return pipes 55 to 57, the maininlet refrigerant pipe 16, and the first to third inletrefrigerant pipes 18 a to 18 c before being equally distributed among thesecompressors 3 a to 3 c. - In an embodiment of the present invention, the
distributor 43 for oil return is mounted on a horizontal portion of the maininlet refrigerant pipe 16 connected to thecompressors 3 a to 3 c via thepipe fixture 62 to take up a horizontal attitude. - That is, the secondary side pipe on the distribution side of the
distributor 43 is connected to the first to third inletrefrigerant pipes 18 a to 18 c and thus is provided in a position very close to the first tothird compressors 3 a to 3 c. - Thus, vibrations of the first to
third compressors 3 a to 3 c being driven are more likely to be propagated to thedistributor 43 via the first to third inletrefrigerant pipes 18 a to 18 c and the maininlet refrigerant pipe 16. - However, as described above, the same vibration system is created by mounting and fixing the
distributor 43 in a horizontal attitude to the maininlet refrigerant pipe 16 so that a pipe fatigue fracture can be prevented. - If the distributor is mounted in a vertical attitude, it takes a lot of time and effort to correct the inclination of the distributor and dimensional control of connection pipes is troublesome, but according to the present embodiment, the
distributor 43 in a horizontal attitude is mounted and fixed to the maininlet refrigerant pipe 16 and thus, no time and effort is needed for the control so that it becomes possible to reduce product variations and cut production costs. - In the
outdoor unit 1 including a plurality of compressors, operating compressors and non-operating compressors may be mixed. In such an operation condition, the ratio of lubricating oil flowing back via the oil balancing circuit may not be equal. - It is assumed, for example, that the
first compressor 3 a and thesecond compressor 3 b are operating and the third compressor is non-operating. In this case, the amount of lubricating oil returned from thedistributor 43 to thefirst compressor 3 a via the firstoil return pipe 55 and the amount of lubricating oil returned to thesecond compressor 3 b via the secondoil return pipe 56 are the same. - The
distributor 43 includes three channels for one inflow port and is configured so that the lubricating oil flows equally through these channels. Naturally, the same amount of lubricating oil is led from thedistributor 43 to the thirdoil return pipe 57 to move to the third compressor 3 c. - However, as described above, the third compressor 3 c is non-operating and thus, the lubricating oil flowing from the third
oil return pipe 57 into the thirdinlet refrigerant pipe 18 c is not drawn into the third compressor 3 c. The lubricating oil has nowhere to go and flows from the thirdinlet refrigerant pipe 18 c into the maininlet refrigerant pipe 16. - Then, due to a suction force of the
second compressor 3 b on the upstream side, almost all lubricating oil flowing into the thirdoil return pipe 57 is led into the second inlet refrigerant pipe 18 b. Here, the lubricating oil joins lubricating oil led via the secondoil return pipe 56 before being drawn into thesecond compressor 3 b. - In the end, the ratio of the amounts of lubricating oil flowing back into the
first compressor 3 a and flowing back into thesecond compressor 3 b becomes 1:2 and while too much lubricating oil is stored in thesecond compressor 3 b, the lubricating oil is insufficient in thefirst compressor 3 a. - In the present invention, the second
oil return pipe 3 b includes the oilreflux cutoff valve 58 and is controlled to close the oilreflux cutoff valve 58 in the above situation. From the above, lubricating oil is led from thedistributor 43 to the firstoil return pipe 55 and the thirdoil return pipe 57, but does not flow to the secondoil return pipe 56. - The lubricating oil flows back from the first
oil return pipe 55 to thefirst compressor 3 a and the lubricating oil flows back from the thirdoil return pipe 57 to thesecond compressor 3 b. No lubricating oil flows back unchangingly to the non-operating compressor 3C. - That is, the second
oil return pipe 56 communicatively connected to themiddle compressor 3 b of three compressors includes the oilreflux cutoff valve 58, which is controlled to close in the above situation. As shown inFIG. 3 , the first outflow port Rf and the third outflow port Rh of thedistributor 43 are positioned at substantially the same height and thus, substantially the same amount of lubricating oil flows into the firstoil return pipe 55 and the thirdoil return pipe 57. That is, the same amount of lubricating oil flows back to thefirst compressor 3 a and thesecond compressor 3 b so that lubricating oil is mutually in proper quantities. - Further, if an oil shortage temporarily arises in one of the first to
third compressors 3 a to 3 c, the amount of lubricating oil held in operating compressors can be adjusted by controlling the oilreflux cutoff valve 58 to open or close. - For example, the
second compressor 3 b may run out of oil while the oilreflux cutoff valve 58 is closed. The lack of oil can be known by comparing detected temperatures of thefourth temperature sensor 39 provided in thebypass pipe 38 and first to third temperature sensors 35 to 37 provided in the first to thirdoil balancing pipes 30 a to 30 c. - If lubricating oil flows to the first to third
oil balancing pipes 30 a to 30 c, detected temperatures of these tubes becomes higher than the detected temperature of thebypass pipe 38. Conversely, if a refrigerant flows to the first to thirdoil balancing pipes 30 a to 30 c, the detected temperature of thebypass pipe 38 becomes higher than the detected temperatures of these tubes, indicating that the first tothird compressors 3 a to 3 c run out of oil. - If, as described above, the
second compressor 3 b is detected to have run out of oil while the oilreflux cutoff valve 58 is closed, the oilreflux cutoff valve 58 is controlled to open. As shown inFIG. 3 , the second outflow port Rg of thedistributor 43 is, among three outflow ports, in the lowest position and thus, more lubricating oil flows into the secondoil return pipe 56 connected to the second outflow port Rg than into theoil return pipes oil return pipe 56 to thesecond compressor 3 b increases to balance the amounts of lubricating oil held by thefirst compressor 3 a and thesecond compressor 3 b. - The present invention is not limited to the above embodiment as it is and can be embodied by modifying structural elements without deviating from the scope thereof in the time of the working. Then, various inventions can be formed by appropriately combining a plurality of structural elements disclosed in the above embodiment.
- According to the present invention, an air conditioner achieving effects such as being easy and reliable to fix a distributor to reduce production variations and being able to prevent a pipe fatigue fracture accompanying a compressor being driven.
- While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Claims (2)
1. An air conditioner configuring a refrigerating cycle by an outdoor unit including a plurality of compressors connected in parallel and a plurality of indoor units, comprising:
an oil balancing pipe that extracts lubricating oil stored in each of the compressors in which a specified amount of the lubricating oil or more is stored;
a distributor that leads lubricating oil liquor from the oil balancing pipe and distributes the lubricating oil liquor to a plurality of channels; and
an oil return pipe that communicatively connects a distribution channel of the distributor and a refrigerant inlet pipe of each of the compressors to return the lubricating oil to each of the compressors, wherein
the distributor is mounted and fixed to the refrigerant inlet pipe in a horizontal attitude along a horizontal portion of the refrigerant inlet pipe of the compressors.
2. The air conditioner according to claim 1 , wherein
the compressors include three units in parallel and
an oil reflux cutoff valve is provided in the oil return pipe into which the lubricating oil is most likely to flow.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2010-030526 | 2010-02-15 | ||
JP2010030526 | 2010-02-15 | ||
PCT/JP2011/053165 WO2011099628A1 (en) | 2010-02-15 | 2011-02-15 | Air conditioner |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2011/053165 Continuation WO2011099628A1 (en) | 2010-02-15 | 2011-02-15 | Air conditioner |
Publications (1)
Publication Number | Publication Date |
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US20120304685A1 true US20120304685A1 (en) | 2012-12-06 |
Family
ID=44367891
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US13/572,948 Abandoned US20120304685A1 (en) | 2010-02-15 | 2012-08-13 | Air conditioner |
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Country | Link |
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US (1) | US20120304685A1 (en) |
EP (1) | EP2538155B1 (en) |
JP (1) | JP5655014B2 (en) |
CN (1) | CN102753913B (en) |
WO (1) | WO2011099628A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
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US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
CN104990307A (en) * | 2015-08-05 | 2015-10-21 | 珠海格力电器股份有限公司 | Air conditioner, compression module, and compression module group |
CN105180493A (en) * | 2015-09-01 | 2015-12-23 | 珠海格力电器股份有限公司 | Compressor module, multi-module unit and oil-balancing control method for multi-module unit |
US20160116196A1 (en) * | 2014-10-27 | 2016-04-28 | Lg Electronics Inc. | Oil separator and air conditioner including an oil separator |
US20170159976A1 (en) * | 2015-12-08 | 2017-06-08 | Bitzer Kuehlmaschinenbau Gmbh | Cascading oil distribution system |
US9683751B2 (en) | 2012-09-21 | 2017-06-20 | Toshiba Carrier Corporation | Outdoor unit for multi-type air conditioner |
US20180195773A1 (en) | 2017-01-12 | 2018-07-12 | Emerson Climate Technologies, Inc. | Micro Booster Supermarket Refrigeration Architecture |
Families Citing this family (2)
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US9976783B2 (en) * | 2013-09-24 | 2018-05-22 | Mitsubishi Electric Corporation | Refrigeration cycle apparatus |
JP7477431B2 (en) | 2020-11-18 | 2024-05-01 | 三菱重工サーマルシステムズ株式会社 | Refrigeration equipment |
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- 2011-02-15 JP JP2011553917A patent/JP5655014B2/en active Active
- 2011-02-15 WO PCT/JP2011/053165 patent/WO2011099628A1/en active Application Filing
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JPH085169A (en) * | 1994-06-21 | 1996-01-12 | Matsushita Refrig Co Ltd | Air conditioner |
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Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9683751B2 (en) | 2012-09-21 | 2017-06-20 | Toshiba Carrier Corporation | Outdoor unit for multi-type air conditioner |
US10012419B2 (en) * | 2014-02-05 | 2018-07-03 | Lg Electronics Inc. | Heat-pump system |
US20150219372A1 (en) * | 2014-02-05 | 2015-08-06 | Lg Electronics Inc. | Heat-Pump System |
US20160116196A1 (en) * | 2014-10-27 | 2016-04-28 | Lg Electronics Inc. | Oil separator and air conditioner including an oil separator |
US10684049B2 (en) * | 2014-10-27 | 2020-06-16 | Lg Electronics Inc. | Oil separator and air conditioner including an oil separator |
CN104990307A (en) * | 2015-08-05 | 2015-10-21 | 珠海格力电器股份有限公司 | Air conditioner, compression module, and compression module group |
CN105180493A (en) * | 2015-09-01 | 2015-12-23 | 珠海格力电器股份有限公司 | Compressor module, multi-module unit and oil-balancing control method for multi-module unit |
US9939179B2 (en) * | 2015-12-08 | 2018-04-10 | Bitzer Kuehlmaschinenbau Gmbh | Cascading oil distribution system |
US20170159976A1 (en) * | 2015-12-08 | 2017-06-08 | Bitzer Kuehlmaschinenbau Gmbh | Cascading oil distribution system |
US20180195773A1 (en) | 2017-01-12 | 2018-07-12 | Emerson Climate Technologies, Inc. | Micro Booster Supermarket Refrigeration Architecture |
US20180195781A1 (en) * | 2017-01-12 | 2018-07-12 | Emerson Climate Technologies, Inc. | Oil Management For Micro Booster Supermarket Refrigeration System |
US10634424B2 (en) * | 2017-01-12 | 2020-04-28 | Emerson Climate Technologies, Inc. | Oil management for micro booster supermarket refrigeration system |
US10969165B2 (en) | 2017-01-12 | 2021-04-06 | Emerson Climate Technologies, Inc. | Micro booster supermarket refrigeration architecture |
Also Published As
Publication number | Publication date |
---|---|
CN102753913A (en) | 2012-10-24 |
JPWO2011099628A1 (en) | 2013-06-17 |
EP2538155A4 (en) | 2018-04-04 |
JP5655014B2 (en) | 2015-01-14 |
CN102753913B (en) | 2015-10-21 |
EP2538155A1 (en) | 2012-12-26 |
EP2538155B1 (en) | 2023-07-19 |
WO2011099628A1 (en) | 2011-08-18 |
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Owner name: TOSHIBA CARRIER CORPORATION, JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KIGUCHI, YUKIO;REEL/FRAME:028774/0375 Effective date: 20120716 |
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