Patent Publication Number: US-11656013-B2

Title: Distributor and refrigeration cycle apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a U.S. national stage application of PCT/JP2018/021609 filed on Jun. 5, 2018, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a distributor and a refrigeration cycle apparatus. 
     BACKGROUND ART 
     In a conventional refrigeration cycle apparatus, a distributor for evenly flowing refrigerant to multiple refrigerant paths of a heat exchanger is used. For example, Japanese Patent No. 3842999 (PTL 1) discloses a two-branch distributor including a U-bend bent into a U-shape and an inflow pipe serving as a flow inlet of the U-bend. In the distributor disclosed in PTL 1, the inflow pipe is connected to a junction between a bent pipe portion and a straight pipe portion of the U-bend while avoiding the bent pipe portion. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent No. 3842999 
     SUMMARY OF INVENTION 
     Technical Problem 
     In the distributor disclosed in PTL 1, gas-liquid two-phase refrigerant flows into the bent pipe portion of the U-bend while spreading from the inflow pipe, and accordingly, part of the gas-liquid two-phase refrigerant flows into the bent pipe portion without contacting the straight pipe portion. As a result, a large amount of gas-liquid two-phase refrigerant flows through the bent pipe portion, which makes it difficult to evenly distribute the refrigerant to the bent pipe portion and the straight pipe portion. Such uneven distribution of the refrigerant may lead to lower-efficiency heat exchange in the heat exchanger. 
     The present invention has been made in view of the above problem and has an object to provide a distributor that facilitates even distribution of refrigerant and a refrigeration cycle apparatus including the distributor. 
     Solution To Problem 
     A distributor of the present invention includes an upstream flow path and a downstream flow path. The upstream flow path extends in a first direction. The downstream flow path is located downstream of the upstream flow path in a refrigerant flow. The downstream flow path has a branch portion and a bent portion. The branch portion has a first connecting portion connected to the upstream flow path to branch the refrigerant flow from the first connecting portion in a second direction intersecting the first direction. The bent portion has a second connecting portion connected to the branch portion and is located downstream of the branch portion in the refrigerant flow. The second connecting portion of the bent portion is located downstream of the first connecting portion of the branch portion in the refrigerant flow. 
     Advantageous Effects of Invention 
     In the distributor according to the present invention, the second connecting portion of the bent portion is located downstream of the first connecting portion of the branch portion in the refrigerant flow, and accordingly, the refrigerant flows through the branch portion from the first connecting portion to the second connecting portion. The refrigerant flowing from the first connecting portion into the branch portion while spreading is thus restrained from flowing into the bent portion without contacting the branch portion. The refrigerant flow is thus easily branched evenly in the branch portion. This facilitates even distribution of the refrigerant. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    schematically shows a refrigeration cycle apparatus in Embodiment 1 of the present invention. 
         FIG.  2    schematically shows a heat exchanger in Embodiment 1 of the present invention. 
         FIG.  3    schematically shows a distributor in Embodiment 1 of the present invention. 
         FIG.  4    schematically shows a distributor in Modification 1 of Embodiment 1 of the present invention. 
         FIG.  5    schematically shows a distributor in Modification 2 of Embodiment 1 of the present invention. 
         FIG.  6    is a graph showing a relation between a distance from a first connecting portion to a second connecting portion and a distribution ratio of a flow into a bent portion in Embodiment 1 of the present invention. 
         FIG.  7    schematically shows a distributor in Embodiment 2 of the present invention. 
         FIG.  8    is an exploded view of a distributor in Modification 1 of Embodiment 2 of the present invention. 
         FIG.  9    schematically shows a distributor in Modification 2 of Embodiment 2 of the present invention. 
         FIG.  10    schematically shows a distributor in Embodiment 3 of the present invention. 
         FIG.  11    schematically shows a distributor in Embodiment 4 of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the drawings. In the drawings described hereinafter, identical or corresponding parts are identically denoted, which is common throughout the specification. Also, the modes of the constituent elements described throughout the specification are merely by way of example, and they are not limited to the embodiments described herein. 
     Embodiment 1 
     A refrigeration cycle apparatus  100  in Embodiment 1 of the present invention will be described with reference to  FIG.  1   .  FIG.  1    shows a configuration of refrigeration cycle apparatus  100  in the present embodiment and also shows refrigerant flows during heating operation and during cooling operation. Refrigeration cycle apparatus  100 , such as a room-air conditioner for home use or a package air conditioner for store or office use, in which one outdoor heat exchanger and one indoor heat exchanger are mounted, will be described below by way of example. Refrigeration cycle apparatus  100  according to the present embodiment can be used in, for example, a heat pump apparatus, a water heater, or a refrigeration apparatus. 
     Refrigeration cycle apparatus  100  in the present embodiment includes a compressor  1 , a four-way valve  2 , an indoor heat exchanger  3 , an expansion valve  4 , an outdoor heat exchanger  5 , an outdoor fan  6 , and an indoor fan  7 . Compressor  1 , four-way valve  2 , indoor heat exchanger  3 , expansion valve  4 , and outdoor heat exchanger  5  are connected to each other by pipes. 
     Compressor  1  is configured to compress sucked refrigerant and discharge the refrigerant. Four-way valve  2  is configured to switch refrigerant flows to indoor heat exchanger  3  and outdoor heat exchanger  5  between during heating operation and during cooling operation. Indoor heat exchanger  3  serves to perform heat exchange between the refrigerant and indoor air. Expansion valve  4  is a throttle device that decompresses the refrigerant. Expansion valve  4  is, for example, a capillary tube or an electronic expansion valve. Outdoor heat exchanger  5  serves to perform heat exchange between the refrigerant and outdoor air. 
     During heating operation, indoor heat exchanger  3  functions as a condenser, and outdoor heat exchanger  5  functions as an evaporator. During cooling operation, indoor heat exchanger  3  functions as an evaporator, and outdoor heat exchanger  5  functions as a condenser. Each of indoor heat exchanger  3  and outdoor heat exchanger  5  includes, for example, a heat transfer tube PI, through which the refrigerant flows, and fins FI, which are attached to the outside of heat transfer tube PI (see  FIG.  2   ). Outdoor fan  6  is configured to supply air to outdoor heat exchanger  5 . Indoor fan  7  is configured to supply air to indoor heat exchanger  3 . 
     In  FIG.  1   , the refrigerant flow during heating operation is indicated by the solid line, and the refrigerant flow during cooling operation is indicated by the broken line. During heating operation, high-temperature, high-pressure gas refrigerant compressed by compressor  1  flows through four-way valve  2  and through a point A into indoor heat exchanger  3 . The gas refrigerant condenses while flowing through indoor heat exchanger  3 , and is cooled by the air flowed by indoor fan  7  to be liquefied. The liquid refrigerant after the liquefaction flows through a point B into expansion valve  4 . The liquid refrigerant flows through expansion valve  4  to enter a two-phase refrigerant state in which low-temperature, low-pressure gas refrigerant and liquid refrigerant coexist. 
     The refrigerant in the two-phase refrigerant state flows through a point C into outdoor heat exchanger  5 . The two-phase refrigerant evaporates while flowing through outdoor heat exchanger  5 , and is heated by the air flowed by outdoor fan  6  to be gasified. The gas refrigerant after the gasification flows through a point D into four-way valve  2 . The gas refrigerant returns to compressor  1  through four-way valve  2 . Through such a cycle, a heating operation of heating indoor air is performed. 
     During cooling operation, four-way valve  2  is switched so as to flow refrigerant in a direction opposite to that during heating operation. In other words, the high-temperature, high-pressure gas refrigerant compressed by compressor  1  flows through four-way valve  2  and through point D into outdoor heat exchanger  5 . The gas refrigerant condenses while flowing through outdoor heat exchanger  5  and is cooled by the air flowed by outdoor fan  6  to be liquefied. The liquid refrigerant after the liquefaction flows through point C into expansion valve  4 . The liquid refrigerant flows through the expansion valve to enter the two-phase refrigerant state in which low-temperature, low-pressure gas refrigerant and liquid refrigerant coexist. 
     The refrigerant in the two-phase refrigerant state flows through point B into indoor heat exchanger  3 . The two-phase refrigerant evaporates while flowing through indoor heat exchanger  3  and is heated by the air flowed by indoor fan  7  to be gasified. The gas refrigerant after the gasification flows through point A into four-way valve  2 . The gas refrigerant returns to compressor  1  through four-way valve  2 . Through such a cycle, a cooling operation of cooling indoor air is performed. 
     Next, a heat exchanger in the present embodiment will be described with reference to  FIG.  2   . The present embodiment will describe, by way of example, a configuration in which a heat exchanger is used as outdoor heat exchanger  5  during heating operation in refrigeration cycle apparatus  100 . The heat exchanger of the present embodiment can also be used as indoor heat exchanger  3 . 
       FIG.  2    schematically shows outdoor heat exchanger  5  in the present embodiment.  FIG.  2 ( a )  is a left lateral view of outdoor heat exchanger  5 .  FIG.  2 ( b )  is a front view of outdoor heat exchanger  5 .  FIG.  2 ( c )  is a right lateral view of outdoor heat exchanger  5 . For the purpose of illustration,  FIG.  2 ( b )  does not show heat transfer tube PI and shows only some of fins FI. 
     Outdoor heat exchanger  5  includes heat transfer tube PI, fins FI, and a distributor  10 . Heat transfer tube PI passes through fins FI. Heat transfer tube PI includes a plurality of straight portions extending so as to pass through fins FI. The straight portions are connected in series with each other. Distributor  10  is connected to two straight portions. 
     In outdoor heat exchanger  5 , gas-liquid two-phase refrigerant which has flowed in from an inflow portion IN in  FIG.  2 ( c )  flows through part of outdoor heat exchanger  5  and is subjected to heat exchange with the air flowed by outdoor fan  6  ( FIG.  1   ). At this time, when a degree of dryness X, indicating a ratio of a mass velocity of gas to an overall mass velocity of gas-liquid two-phase refrigerant, is used, degree of dryness X is about 0.05 or more and about 0.25 or less (X=0.05-0.25). As the liquid refrigerant of the gas-liquid two-phase refrigerant evaporates through heat exchange between the refrigerant and air, the gas-liquid two-phase refrigerant completes flowing through part of outdoor heat exchanger  5  at a varying ratio of the mass velocity of gas to the overall mass velocity. 
     Then, distributor  10  of two-branch type distributes the gas-liquid two-phase refrigerant to a flow path R 1  and a flow path R 2 . At this time, the gas-liquid two-phase refrigerant that flows into distributor  10  can have a degree of dryness X of about 0.10 or more and about 0.60 or less (0.10-0.60). This degree of dryness depends on a ratio of a part of outdoor heat exchanger  5 , through which the gas-liquid two-phase refrigerant flows before reaching distributor  10 , to the entire outdoor heat exchanger  5 . The gas-liquid two-phase refrigerant which has flowed through flow path R 1  and the gas-liquid two-phase refrigerant which has flowed through flow path R 2  flow through other parts of outdoor heat exchanger  5  and meet together after being subjected to heat exchange with air. Then, the resultant gas-liquid two-phase refrigerant reaches an outflow portion OUT. 
     Distributor  10  in the present embodiment will be described in detail with reference to  FIG.  3   .  FIG.  3    schematically shows distributor  10  in the present embodiment. As shown in  FIG.  3   , distributor  10  in the present embodiment includes an upstream flow path  11  and a downstream flow path  12 . Each of upstream flow path  11  and downstream flow path  12  may be configured of a tube (pipe). 
     Upstream flow path  11  extends in a first direction YD. Upstream flow path  11  is connected to downstream flow path  12 . A portion of upstream flow path  11  which is connected to downstream flow path  12  may be configured as a linear portion. Upstream flow path  11  is also connected to heat transfer tube PI. In other words, one end of upstream flow path  11  is connected to downstream flow path  12 , and the other end of upstream flow path  11  is connected to heat transfer tube PI. 
     Downstream flow path  12  is located downstream of upstream flow path  11  in refrigerant flow. Downstream flow path  12  has a branch portion  12   a  and a bent portion  12   b . Branch portion  12   a  has a first connecting portion CP 1  connected to upstream flow path  11 . Branch portion  12   a  is configured to branch a refrigerant flow from first connecting portion CP 1  in a second direction XD intersecting first direction YD. Branch portion  12   a  is configured to branch a refrigerant flow from first connecting portion CP 1  to flow path R 1  and flow path R 2 . Branch portion  12   a  extends in second direction XD. First direction YD and second direction XD may be orthogonal to each other. Branch portion  12   a  may be configured as a straight portion. 
     Bent portion  12   b  is configured to bend with respect to branch portion  12   a . In the present embodiment, bent portion  12   b  extends opposite to upstream flow path  11 . Bent portion  12   b  is also configured to fold back downstream flow path  12  from the positive direction to the negative direction of second direction XD. Bent portion  12   b  has a second connecting portion CP 2  connected to branch portion  12   a . Bent portion  12   b  is located downstream of branch portion  12   a  in refrigerant flow. Second connecting portion CP 2  of bent portion  12   b  is located downstream of first connecting portion CP 1  of branch portion  12   a  in refrigerant flow. In second direction XD, thus, a length L between first connecting portion CP 1  and second connecting portion CP 2  is greater than zero. 
     Distributor  10  in Modification 1 of the present embodiment will be described with reference to  FIG.  4   . In distributor  10  in Modification 1 of the present embodiment, in second direction XD, length L between first connecting portion CP 1  and second connecting portion CP 2  is greater than or equal to a width W of upstream flow path  11 , as shown in  FIG.  4   . In this case, width W of upstream flow path  11  is the upper limit of length L. 
     Distributor  10  in Modification 2 of the present embodiment will be described with reference to  FIG.  5   . In distributor  10  in Modification 2 of the present embodiment, in second direction XD, length L between first connecting portion CP 1  and second connecting portion CP 2  is greater than or equal to a dimension obtained by multiplying a width h of branch portion  12   a  in first direction YD by tan 15°, as shown in  FIG.  5   . 
     As gas-liquid two-phase refrigerant that has flowed from upstream flow path  11  into downstream flow path  12  flows in the positive direction of first direction YD, the gas-liquid two-phase refrigerant collides with a traverse wall  21  of branch portion  12   a  while spreading from first connecting portion CP 1  in the range of a spread angle θ. Spread angle θ is an angle at which refrigerant spreads from first connecting portion CP 1  in second direction XD with respect to first direction YD. 
     Traverse wall  21  faces the flow outlet of upstream flow path  11 . Branch portion  12   a  has a length L 1  of flow path R 1  and a length L 2  of flow path R 2  in second direction XD. One gas-liquid two-phase refrigerant that has collided with traverse wall  21  flows through flow path R 1  in the positive direction of second direction XD and travels a distance of length L 1  with width h, and then travels toward bent portion  12   b . The other gas-liquid two-phase refrigerant that has collided with traverse wall  21  flows through flow path R 2  in the negative direction of second direction XD and travels a distance of length L 2  with width h. Herein, length L 1  and length L 2  have relations represented by Expressions (1) and (2) below.
 
 L 2≥ L 1 ≥h  tan θ+0.5 W   (1)
 
θ=15°  (2)
 
     Even at the same mass velocity, the speed of the gas-liquid two-phase refrigerant flowing per unit time increases as degree of dryness X is higher, resulting in a larger pressure loss caused by the collision with traverse wall  21 . Thus, spread angle θ of the gas-liquid two-phase refrigerant tends to be large so as to avoid a pressure loss caused by a collision. In view of the above, the inventor has found through experimental research that spread angle θ in Expression (2) less easily exceeds 15 degrees (θ=15°) if degree of dryness X used in outdoor heat exchanger  5  is 0.10 or more and 0.60 or less (X=0.10-0.60). Thus, distributor  10  of two-branch type that satisfies the relations of Expressions (1) and (2) above can be mounted in a heat exchanger with a minimum length L 1 . 
       FIG.  6    is a characteristic diagram showing length L 1  of flow path R 1  of branch portion  12   a  and a distribution ratio of a mass flow rate at which refrigerant flows on the bent portion  12   b  side in the present embodiment, where a mass flow rate at which refrigerant flows through upstream flow path  11  is 100%.  FIG.  6    reveals that refrigerant is distributed evenly when length L 1  satisfies the relation of Expression (1), whereas refrigerant of a large mass flow rate flows on the bent portion  12   b  side when length L 1  does not satisfy the relation of Expression (1). 
     Next, the function and effect of the present embodiment will be described. 
     In distributor  10  according to the present embodiment, second connecting portion CP 2  of bent portion  12   b  is located downstream of first connecting portion CP 1  of branch portion  12   a  in refrigerant flow, and accordingly, refrigerant flows through branch portion  12   a  from first connecting portion CP 1  to second connecting portion CP 2 . This restrains refrigerant flowing from first connecting portion CP 1  into branch portion  12   a  while spreading from flowing into the bent portion without contacting branch portion  12   a . The refrigerant flow can thus be easily branched evenly in branch portion  12   a . This facilitates even distribution of the refrigerant. This leads to higher-efficiency heat exchange in the heat exchanger. 
     In distributor  10  according to Modification 1 of the present embodiment, in second direction XD, length L between first connecting portion CP 1  and second connecting portion CP 2  is smaller than or equal to width W of upstream flow path  11 . This can reduce a size of distributor  10 . 
     In distributor  10  according to Modification 2 of the present embodiment, in second direction XD, length L between first connecting portion CP 1  and second connecting portion CP 2  is greater than or equal to a dimension obtained by multiplying width h of branch portion  12   a  in first direction YD by tan 15°. This enables even distribution of the refrigerant. 
     As described above, distributor  10  in the present embodiment can have a size reduced to a minimum required size while evenly distributing gas-liquid two-phase refrigerant, which has been distributed unevenly in a conventional distributor. Distributor  10  having a minimum required size reduced as described above can accordingly contribute to reductions in material cost and mounting space. 
     The refrigeration cycle apparatus in the present embodiment, which includes distributor  10  described above, can thus achieve the function and effect described above. 
     Embodiment 2 
     With reference to  FIGS.  7  to  9   , Embodiment 2 of the present invention will describe a mode in which the opposite ends of downstream flow path  12  run in second direction XD and change their directions of travel in a curved manner or at a right angle, and subsequently, travel in first direction YD or a synthetic direction of first direction YD and second direction XD. 
     Distributor  10  in the present embodiment as shown in  FIG.  7    will be described in detail.  FIG.  7    schematically shows distributor  10  in the present embodiment. As shown in  FIG.  7   , downstream flow path  12  is configured in an S shape. Downstream flow path  12  has a first downstream flow path portion  121  and a second downstream flow path portion  122 . First downstream flow path portion  121  is configured to travel a distance L 1  from the central axis of upstream flow path  11  in the negative direction of second direction XD, change the direction of travel at a right angle, and then travel in the positive direction of first direction YD. Second downstream flow path portion  122  is configured to travel a distance L 2  from the central axis of upstream flow path  11  in the positive direction of second direction XD, change the direction of travel at a right angle, and then travel in the negative direction of first direction YD. In second downstream flow path portion  122 , thus, a positive-going component of a vector of the refrigerant in first direction YD is zero. 
     Bent portion  12   b  of downstream flow path  12  has a first downstream portion  12   b   1  and a second downstream portion  12   b   2 . Second downstream portion  12   b   2  is disposed opposite to first downstream portion  12   b   1  with respect to branch portion  12   a . First downstream portion  12   b   1  extends in the positive direction of first direction YD. First downstream portion  12   b   1  may be disposed at a right angle with respect to branch portion  12   a . Second downstream portion  12   b   2  extends in the negative direction of first direction YD opposite to the positive direction. Second downstream portion  12   b   2  may be disposed at a right angle with respect to branch portion  12   a.    
     In second downstream flow path portion  122 , gas-liquid two-phase refrigerant that flows in from upstream flow path  11  needs to change the direction of travel and travel in the negative direction of first direction YD. Thus, even if length L 2  does not satisfy Expression (1) above, the gas-liquid two-phase refrigerant that flows in from the flow outlet of upstream flow path  11  while spreading at spread angle θ inevitably collides with traverse wall  21 . 
     On the other hand, in first downstream flow path portion  121 , if length L 1  does not satisfy Expression (1) above, the gas-liquid two-phase refrigerant that flows in from upstream flow path  11  has spread angle θ, and accordingly, travels without colliding with traverse wall  21 . Thus, length L 1  needs to satisfy Expression (1) above. On the other hand, length L 2  is not limited to Expression (1) above. 
     Referring to  FIG.  8   , distributor  10  in the present embodiment may be configured by overlaying plate-shaped bodies on each other.  FIG.  8    is an exploded perspective view of distributor  10  in Modification 1 of the present embodiment. 
     As shown in  FIG.  8   , distributor  10  in Modification 1 of the present invention includes a first plate  101 , a second plate  102 , and a third plate  103 . First plate  101 , second plate  102 , and third plate  103  are overlaid on each other. In other words, first plate  101 , second plate  102 , and third plate  103  are stacked on each other. First plate  101 , second plate  102 , and third plate  103  may have an equal plate thickness. 
     First plate  101  has a first surface S 1  and a second surface S 2  opposite to first surface S 1 . First plate  101  is provided with a channel  101   a  passing through first surface S 1  and second surface S 2 . Second plate  102  is attached to first surface S 1  of first plate  101 . Second plate  102  is provided with a flow inlet  102   a  communicating with channel  101   a . Third plate  103  is attached to second surface S 2  of first plate  101 . Third plate  103  is provided with flow outlets  103   a  communicating with channel  101   a.    
     Channel  101   a  of first plate  101  configures upstream flow path  11  and downstream flow path  12 . Flow inlet  102   a  of second plate  102  is connected to upstream flow path  11 . Flow outlets  103   a  of third plate  103  are connected to downstream flow path  12 . 
     When distributor  10  is configured of a circular pipe typically used, it is difficult to form right-angle portions of first downstream flow path portion  121  and second downstream flow path portion  122 . Thus, a flow path can also be formed by punching plate-shaped bodies as shown in  FIG.  8    by pressing. This can improve manufacturability and reduce processing cost. 
     Although  FIG.  8    shows distributor  10  configured of three plate-shaped bodies, namely, first plate  101 , second plate  102 , and third plate  103 , the number of plate-shaped bodies is not limited to three. For example, each of first plate  101 , second plate  102 , and third plate  103  may be configured of multiple plate-shaped bodies. Also, the shape of the plate-shaped body is not limited to a rectangular shape. 
     The configuration of distributor  10  configured of plate-shaped bodies as shown in  FIG.  8    may be used in Embodiment 2, as well as in Embodiment 1 and Embodiment 3 and Embodiment 4 described below. 
     Referring to  FIG.  9   , distributor  10  in the present embodiment may be used in a mode in which first downstream flow path portion  121  and second downstream flow path portion  122  travel in a curved flow path.  FIG.  9    schematically shows distributor  10  in Modification 2 of the present embodiment. As shown in  FIG.  9   , first downstream flow path portion  121  is configured to be folded back in the positive direction of second direction XD. Specifically, first downstream portion  12   b   1  is configured to be inclined in the positive direction of second direction XD toward the central axis of upstream flow path  11 . Second downstream flow path portion  122  is configured to be folded back in the negative direction of second direction XD. Specifically, second downstream portion  12   b   2  is configured to be inclined in the negative direction of second direction XD toward the central axis of upstream flow path  11 . 
     Next, the function and effect of the present embodiment will be described. 
     In distributor  10  in the present embodiment, first downstream portion  12   b   1  extends in the positive direction of first direction YD, and second downstream portion  12   b   2  extends in the negative direction of first direction YD opposite to the positive direction. In second downstream portion  12   b   2 , thus, the positive-going component of the vector of the refrigerant in first direction YD is zero. Length L 2  of branch portion  12   a  to second downstream portion  12   b   2  can thus be reduced. This can reduce a size of distributor  10 . 
     As described above, distributor  10  in the present embodiment can have length L 1  in first downstream flow path portion  121  which is reduced to a minimum required length within the range that satisfies Expression (1) above and length L 2  in second downstream flow path portion  122  that can be reduced without being restricted by Expression (1) above. Thus, distributor  10  in the present embodiment can have a size reduced to a minimum required size while evenly distributing gas-liquid two-phase refrigerant, which has been distributed unevenly in a conventional distributor. Distributor  10  having a minimum required size reduced as described above can accordingly contribute to reductions in material cost and mounting space. 
     In distributor  10  in Modification 1 of the present embodiment, channel  101   a  of first plate  101  configures downstream flow path  12 , and accordingly, downstream flow path  12  can be configured in an appropriate shape (e.g., right-angle shape) by punching first plate  101  by pressing. This improves manufacturability and reduces processing cost. 
     Embodiment 3 
     Referring to  FIG.  10   , Embodiment 3 of the present invention will describe a mode in which a flow path width of upstream flow path  11  shown in Embodiment 2 decreases from upstream to downstream.  FIG.  10    schematically shows distributor  10  in the present embodiment. As shown in  FIG.  10   , in distributor  10  in the present embodiment, upstream flow path  11  has a first width W 1  and a second width W 2 . First width W 1  is a width of a portion disposed upstream of first connecting portion CP 1  in refrigerant flow. Second width W 2  is a width of a portion connected to first connecting portion CP 1 . Second width W 2  is smaller than first width W 1 . Upstream flow path  11  is configured to decrease from first width W 1  to second width W 2 . Upstream flow path  11  has a tapered shape continuously decreasing from first width W 1  to second width W 2 . 
     In distributor  10  in the present embodiment, the flow path width of upstream flow path  11  decreases from first width W 1  to second width W 2 , and accordingly, spreading of the refrigerant from the flow outlet of upstream flow path  11  to traverse wall  21  can be restrained. In such a case, Expression (1) above has relations of Expression (3) below and Expression (2).
 
 L 1 ≥h  tan θ+0.5 W 2  (3)
 
     Next, the function and effect in the present embodiment will be described. 
     In distributor  10  in the present embodiment, upstream flow path  11  is configured to decrease from first width W 1  to second width W 2 . Thus, length L 1  and length L 2  from the flow outlet of upstream flow path  11  to bent portion  12   b  can be reduced. This can reduce a size of distributor  10 . 
     As described above, distributor  10  in the present embodiment can have length L 1  in first downstream flow path portion  121  which is reduced to be smaller than in Embodiment 2. Distributor  10  in the present embodiment can thus have a size reduced to a minimum required size while evenly distributing gas-liquid two-phase refrigerant, which has been distributed unevenly in a conventional distributor. Distributor  10  having a minimum required size reduced as described above can accordingly contribute to reductions in material cost and mounting space. 
     Embodiment 4 
     Referring to  FIG.  11   , Embodiment 4 of the present invention will describe a mode in which the central axis of upstream flow path  11  described and shown in Embodiment 3 has an inclination angle θ 1  with respect to the central axis of branch portion  12   a  of downstream flow path  12 . 
       FIG.  11    schematically shows distributor  10  in the present embodiment. As shown in  FIG.  11   , in distributor  10  in the present embodiment, first direction YD is inclined with respect to the direction orthogonal to second direction XD. Upstream flow path  11  may be configured to be inclined with respect to the direction of gravity. Upstream flow path  11  is inclined toward second downstream portion  12   b   2  extending in the negative direction of first direction YD. In other words, upstream flow path  11  is inclined opposite to first downstream portion  12   b   1  extending in the positive direction of first direction YD. 
     Upstream flow path  11  is inclined at an inclination angle θ 1  from the central axis of branch portion  12   a . Thus, spreading of the refrigerant from the flow outlet of upstream flow path  11  to traverse wall  21  can be restrained. Inclination angle θ 1  is as shown in Expressions (4) and (5) below.
 
82°≤θ1&lt;90°  (4)
 
90°&lt;θ1≤98°  (5)
 
     When θ 1  is out of the range represented by Expressions (4) and (5), the refrigerant that flows out of upstream flow path  11  has a large amount of kinetic energy for travel in second direction XD, and accordingly, a large amount of refrigerant flows to downstream flow path  12  in the direction of travel without being evenly distributed to two branches even when the refrigerant has collided with traverse wall  21 . The inventor has found through experimental research that a kinetic energy component for travel in second direction XD is negligibly small when inclination angle θ 1  is within the range represented by Expressions (4) and (5). 
     Next, the function and effect of the present embodiment will be described. 
     In distributor  10  in the present embodiment, first direction YD is inclined with respect to the direction orthogonal to second direction XD. Thus, as upstream flow path  11  is inclined with respect to bent portion  12   b  extending in the positive direction of first direction YD, refrigerant can less easily flow into bent portion  12   b . This can reduce a size of distributor  10 . 
     As described above, distributor  10  in the present embodiment can have length L 1  of first downstream flow path portion  121  which is reduced to be smaller than in Embodiment 3. Distributor  10  in the present embodiment can have a size reduced to a minimum required size while evenly distributing gas-liquid two-phase refrigerant, which has been distributed unevenly in a conventional distributor. Distributor  10  having a minimum required size reduced as described above can accordingly contribute to reductions in material cost and mounting space. 
     The above embodiments can be combined as appropriate. 
     It should be construed that the embodiments disclosed herein are given by way of illustration in all respects, not by way of limitation. It is therefore intended that the scope of the present invention is defined by claims, not only by the embodiments described above, and encompasses all modifications and variations equivalent in meaning and scope to the claims. 
     REFERENCE SIGNS LIST 
       1  compressor;  2  four-way valve;  3  indoor heat exchanger;  4  expansion valve;  5  outdoor heat exchanger;  6  outdoor fan;  7  indoor fan;  10  distributor;  11  upstream flow path;  12  downstream flow path;  12   a  branch portion;  12   b  bent portion;  12   b   1  first downstream portion;  12   b   2  second downstream portion;  100  refrigeration cycle apparatus;  101  first plate;  101   a  channel;  102  second plate;  102   a  flow inlet;  103  third plate;  103   a  flow outlet;  121  first downstream flow path portion;  122  second downstream flow path portion; CP 1  first connecting portion; CP 2  second connecting portion; S 1  first surface; S 2  second surface; W 1  first width; W 2  second width; XD second direction; YD first direction.