Abstract:
A refrigerant guiding pipe has a pipe wall in which an inner chamber is formed; an opening formed in the pipe wall; and a refrigerant guiding wall portion, at least a part of an edge of the refrigerant guiding wall portion being separated from the pipe wall, thereby forming the opening. The refrigerant guiding pipe can help alleviate generation of non-uniform distribution of refrigerant due to layering of gaseous refrigerant and liquid refrigerant.

Description:
FIELD 
       [0001]    The present invention relates to a refrigerant guiding pipe and a heat exchanger having the refrigerant guiding pipe. 
       BACKGROUND 
       [0002]    The inlet and/or outlet manifold of a typical heat exchanger is provided with a refrigerant guiding pipe, and the refrigerant guiding pipe is used as a distributor in the inlet manifold and as a collector in the outlet manifold. 
       SUMMARY 
       [0003]    It is desirable, for example, to provide a refrigerant guiding pipe and a heat exchanger with the refrigerant guiding pipe which can improve uniformity of refrigerant distribution. 
         [0004]    According to an aspect of the present invention, there is provided a refrigerant guiding pipe. The refrigerant guiding pipe comprises a pipe wall in which an inner chamber is formed; an opening formed in the pipe wall; and a refrigerant guiding wall portion, at least a part of an edge of the refrigerant guiding wall portion being separated from the pipe wall, thereby forming the opening. 
         [0005]    According to an aspect of the present invention, at least a part of the refrigerant guiding wall portion is disposed to be substantially inclined with respect to an axial direction of the refrigerant guiding pipe to guide refrigerant passing through the opening, 
         [0006]    According to an aspect of the present invention, at least a middle portion of the refrigerant guiding wall portion in a direction perpendicular to the axial direction of the refrigerant guiding pipe is positioned at an angle of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the axial direction of the refrigerant guiding pipe; at least a portion of the refrigerant guiding wall portion is positioned at an angle of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the axial direction of the refrigerant guiding pipe; or the refrigerant guiding wall portion is positioned at an angle of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the axial direction of the refrigerant guiding pipe. 
         [0007]    According to an aspect of the present invention, at least the middle portion of the refrigerant guiding wall portion in the direction perpendicular to the axial direction of the refrigerant guiding pipe has a section along the axial direction of the refrigerant guiding pipe, and the section is composed of a plurality of substantially straight line-shaped segments or has substantially a shape of a curve; or the refrigerant guiding wall portion has a section along the axial direction of the refrigerant guiding pipe, and the section is composed of a plurality of substantially straight line-shaped segments or has substantially a shape of a curve. 
         [0008]    According to an aspect of the present invention, there is provided a heat exchanger with the refrigerant guiding pipe described herein. 
         [0009]    With some embodiments of the refrigerant guiding pipe, uniformity of refrigerant distribution can be improved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic view of a heat exchanger according to an embodiment of the present invention; 
           [0011]      FIG. 2   a  is a schematic sectional view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0012]      FIG. 2   b  is a schematic view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0013]      FIG. 3   a  is a schematic sectional view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0014]      FIG. 3   b  is an enlarged schematic sectional view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0015]      FIG. 4   a  is a schematic view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0016]      FIGS. 4   b  and  4   c  are partially enlarged schematic views of the refrigerant guiding pipe according to an embodiment; 
           [0017]      FIG. 5   a  is a schematic sectional view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0018]      FIG. 5   b  is a schematic view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0019]      FIG. 6   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0020]      FIG. 6   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0021]      FIG. 6   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0022]      FIG. 7   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0023]      FIG. 7   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0024]      FIG. 7   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0025]      FIG. 8   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0026]      FIG. 8   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0027]      FIG. 8   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0028]      FIG. 9   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0029]      FIG. 9   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0030]      FIG. 9   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0031]      FIG. 10   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0032]      FIG. 10   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0033]      FIG. 10   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0034]      FIG. 11   a  is a schematic front view of a refrigerant guiding pipe according to an embodiment of the present invention; 
           [0035]      FIG. 11   b  is a schematic top view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0036]      FIG. 11   c  is a schematic perspective view of the refrigerant guiding pipe according to an embodiment of the present invention; 
           [0037]      FIG. 12   a  is a schematic sectional view of a refrigerant guiding pipe according to an embodiment of the present invention; and 
           [0038]      FIG. 12   b  is a schematic view of the refrigerant guiding pipe according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    A further description of the invention will be made as below with reference to embodiments of the present invention taken in conjunction with the accompanying drawings. 
         [0040]    As illustrated in  FIG. 1 , a heat exchanger  100  according to an embodiment of the present invention comprises a first manifold  102 ; a second manifold  101  spaced away from the first manifold  102  by a predetermined distance; a heat exchange tube  103  such as a flat tube having two ends respectively connected with the first manifold  102  and the second manifold  101  so that a refrigerant channel in the heat exchange tube  103  is in communication with the first manifold  102  and the second manifold  101 ; a fin  104 ; and a refrigerant guiding pipe  10 , the first manifold  102 , or the second manifold  101 , or both the first manifold  102  and the second manifold  101  being provided with the refrigerant guiding pipe  10  therein. The heat exchanger may be any appropriate heat exchanger such as a heat exchanger with one row of core or a plurality of rows of cores or a heat exchanger with one loop or a plurality of loops. In addition, the heat exchanger may be a micro-channel heat exchanger. For example, the refrigerant guiding pipe may be applied to an inner chamber part of an inlet manifold of a plurality of loops of the micro-channel heat exchanger and an inner chamber part of a manifold between the plurality of loops to guide and distribute two-phase refrigerant. 
         [0041]      FIGS. 2   a  and  2   b  show a refrigerant guiding pipe  10  according to an embodiment. As illustrated in  FIGS. 2   a  and  2   b , the refrigerant guiding pipe  10  comprises a pipe wall  17  in which an inner chamber  19  is formed; an opening  11   a  formed in the pipe wall; and a refrigerant guiding wall portion, at least a part of an edge of the refrigerant guiding wall portion is separated from the pipe wall  17 , thereby forming the opening  11   a.  At least a part of the refrigerant guiding wall portion is disposed to be substantially inclined with respect to an axial direction of the refrigerant guiding pipe to guide refrigerant passing through the opening  11   a.  The refrigerant guiding wall portion is disposed so that a direction of refrigerant flow flowing through the opening  11   a  is substantially inclined with respect to the axial direction of the refrigerant guiding pipe  10 . For example, at least a part of the refrigerant guiding wall portion is positioned at an angle of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the the axial direction of the refrigerant guiding pipe. For example, the refrigerant guiding wall portion is disposed such that refrigerant flow flowing through the opening  11   a  is inclined with respect to the axial direction of the refrigerant guiding pipe by an angle of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees. 
         [0042]    The refrigerant guiding pipe  10  further comprises a protruded wall section  24  projected outside the inner chamber  19 , and at least a first end  241  of the protruded wall section  24  on one side in the axial direction of the refrigerant guiding pipe is separated from the pipe wall  17 , thereby forming the opening  11   a.  The protruded wall section  24  constitutes an example of the refrigerant guiding wall portion. 
         [0043]    At least a middle portion  24   a  of the protruded wall section  24  in a direction perpendicular to the axial direction of the refrigerant guiding pipe or the protruded wall section  24  is inclined with respect to the axial direction of the refrigerant guiding pipe  10 , or at least a portion of the protruded wall section  24  is inclined with respect to the axial direction of the refrigerant guiding pipe  10 . A second end  242  of the protruded wall section  24  is closer to an axis  15  of the refrigerant guiding pipe  10  than the first end  241  of the the protruded wall section  24  opposite to the second end  242 . The middle portion  24   a  extends from the first end  241  to the second end  242  in the axial direction of the refrigerant guiding pipe  10 . 
         [0044]    As illustrated in  FIGS. 2   a  and  2   b , a method of forming the opening  11   a  is to cut a notch with a certain depth in a pipe wall of a circular pipe for forming the refrigerant guiding pipe  10  in a cutting direction perpendicular to the axial direction of the circular pipe, and then to protrude the pipe wall of the circular pipe on one side of the notch in the axial direction. The opening  11   a  and the protruded wall section  24  are thereby formed. An orientation of the notch is determined by two directions, one of which is a depth direction of the notch (i.e., a direction of the notch in depth) directed in a radial direction of the circular pipe (upward and downward directions in  FIG. 2   a ), and the other of which is the cutting direction perpendicular to the depth direction of the notch and the axial direction of the circular pipe. Alternatively, the depth direction of the notch may be positioned at an angle of less than 90 degrees with respect to the radial direction of the circular pipe, and the cutting direction of the notch may be positioned at an angle of less than 90 degrees with respect to the axial direction of the circular pipe. The notch may be any notch in any appropriate orientation. 
         [0045]    As illustrated in  FIGS. 2   a  and  2   b , a circumferential length of the notch on a circumference corresponding to an inner diameter of the refrigerant guiding pipe  10 , i.e., a length of a circular arc of a separated segment  12  at which the first end  241  is separated from the pipe wall  17 , is L, and a distance or pitch between the adjacent openings is d 1 . On the circumference corresponding to the inner diameter of the refrigerant guiding pipe  10 , a ratio of the length L of the circular arc of the separated segment  12 , at which the first end  241  is separated from the pipe wall  17 , to a circumference of a part of the pipe wall  17  corresponding to the separated segment  12  ranges from 0.05 to 0.8. When the refrigerant guiding pipe  10  serves as a distributor, the distances or pitches d 1  between the adjacent openings  11   a  may gradually decrease in a direction in which refrigerant flows in the refrigerant guiding pipe  10 . Alternatively, the distances or pitches d 1  between the adjacent openings  11   a  of the plurality of the openings may be equal to one another. 
         [0046]    In an embodiment, at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe, the section has a shape of a substantially straight line or is substantially straight, and at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe is inclined at an angle γ with respect to the axial direction of the refrigerant guiding pipe  10 . Alternatively, the protruded wall section  24  has a section along the axial direction of the refrigerant guiding pipe, the section has a shape of a substantially straight line or is substantially straight, and the protruded wall section  24  is inclined at an angle γ with respect to the axial direction of the refrigerant guiding pipe  10 . At least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe is positioned at an angle γ of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the axial direction of the refrigerant guiding pipe  10 ; or the protruded wall section  24  is positioned at an angle γ of more than zero degree and less than 90 degrees, desirably from about 5 degrees to about 75 degrees, with respect to the axial direction of the refrigerant guiding pipe  10 . 
         [0047]    In an embodiment, when the refrigerant guiding pipe  10  serves as a distributor, the protruded wall sections  24  are designed such that at least the middle portions  24   a  of at least some of the protruded wall sections  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe or at least some of the protruded wall sections  24  are inclined at the angles γ with respect to the axial direction of the refrigerant guiding pipe  10 , and the inclination angles γ may gradually increase in the direction in which refrigerant flows in the refrigerant guiding pipe  10 . 
         [0048]    The refrigerant guiding pipe  10  with the above configuration may also serve as a collector in the outlet manifold  101 . 
         [0049]    Referring to  FIGS. 1 and 2 , whether the refrigerant guiding pipe  10  serves as a distributer in the inlet manifold  102  or as a collector in the outlet manifold  101 , an end  31  of the refrigerant guiding pipe  10  will be connected to refrigerant piping but the other end  33  will not be connected to the refrigerant piping. Therefore, the refrigerant guiding pipe  10  may be designed such that the distances or pitches d 1  between the adjacent openings  11   a  may gradually decrease in a direction directed from the end  31  of the refrigerant guiding pipe  10  to be connected to refrigerant piping to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 ; and the refrigerant guiding pipe  10  may be designed such that at least the middle portions  24   a  of at least some or all of the protruded wall sections  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe or at least some or all of the protruded wall sections  24  are inclined at the angles γ with respect to the axial direction of the refrigerant guiding pipe  10 , and the inclination angles γ may gradually increase in the direction directed from the end  31  of the refrigerant guiding pipe  10  to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 . 
         [0050]    A row of the openings  11   a  or a plurality of rows of the openings  11   a  such as two or three rows of the openings  11   a  are disposed along the axial direction of the refrigerant guiding pipe  10 . 
         [0051]    The refrigerant guiding pipe  10  may be formed of a circular pipe. The refrigerant guiding pipe  10  may also be formed of a pipe having any other cross section such as an elliptical or rectangular cross section. In addition, the refrigerant guiding pipe  10  may be formed of a pipe having a varying radius. The refrigerant guiding pipe  10  may be formed of any appropriate pipe known in the art. 
         [0052]    Referring to  FIG. 1 , when the above refrigerant guiding pipe  10  is used in the manifold  102  of the heat exchanger  100 , refrigerant flows along the inner chamber of the refrigerant guiding pipe, and the protruded wall section  24  mainly functions to guide the refrigerant. The refrigerant is ejected to an inner cavity of the manifold along a surface of the protruded wall section  24  so that resistance loss is low. A part of the refrigerant can be ejected directly into inner chambers of flat tubes  103  and the remaining refrigerant rushes to an end of the manifold  101  and then flows reversely so that refrigerant is uniformly distributed to the remaining flat tubes  103 . Refrigerant is mixed in the manifold  101  so that gaseous refrigerant and liquid refrigerant are uniformly mixed and do not layer. 
         [0053]      FIGS. 3   a  and  3   b  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. The structure of the refrigerant guiding pipe  10  according to this embodiment may be substantially the same as that of the refrigerant guiding pipe  10  according  FIG. 2  except as described below. 
         [0054]    As illustrated in  FIGS. 3   a  and  3   b , the protruded wall section  24  is bent from the pipe wall  17  at an angle of more than 90 degrees relative to the pipe wall  17 . Except for the second end  242  connected with the pipe wall  17 , the other edges of the protruded wall section  24  are separated from the pipe wall  17 , thereby forming the opening  11   a.  The protruded wall section  24  constitutes an example of the refrigerant guiding wall portion. 
         [0055]      FIGS. 4   a ,  4   b  and  4   c  show structure of a refrigerant guiding pipe  10  according to an embodiment of the present invention. As illustrated in  FIGS. 4   a ,  4   b  and  4   c , the refrigerant guiding pipe  10  differs from the refrigerant guiding pipe  10  of  FIG. 3  in that a plurality of protrusions  25  are disposed on a surface of the protruded wall section  24  facing the opening  11   a.  The plurality of protrusions  25  can disturb refrigerant when the refrigerant is ejected from the opening, so that the two phase refrigerant mixes more uniformly. The protrusions  25  may have a pointed top as illustrated in  FIG. 4   b , or a rounded top as illustrated in  FIG. 4   c.    
         [0056]      FIGS. 5   a  and  5   b  show schematic views of a refrigerant guiding pipe  10  according to an embodiment of the present invention. The refrigerant guiding pipe  10  according to this embodiment may be the same as the refrigerant guiding pipe  10  of  FIG. 2  except as described hereafter. 
         [0057]    As illustrated in  FIGS. 5   a  and  5   b  and referring to  FIGS. 2   a  and  2   b , in the refrigerant guiding pipe  10  of this embodiment, at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of a plurality of substantially straight line-shaped segments or a plurality of substantially straight segments; or the protruded wall section  24  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of a plurality of substantially straight line-shaped segments or a plurality of substantially straight segments. The middle portion  24   a  extends from the first end  241  to the second end  242  in the axial direction of the refrigerant guiding pipe  10 . Alternatively, at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of an arc-like segment; or the protruded wall section  24  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of an arc-like segment. 
         [0058]    An angle between at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  and the axial direction of the refrigerant guiding pipe  10  may gradually decrease from the first end  241  to the second end  242 , or an angle between the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10  may gradually decrease from the first end  241  to the second end  242 . 
         [0059]    At the middle portion  24   a  of the protruded wall section  24 , an angle β between the second end  242  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe may be larger than 0 degree and less than 45 degrees and an angle θ between the first end  241  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe may be larger than 45 degrees and less than 90 degrees. Alternatively, at the protruded wall section  24 , an angle β between the second end  242  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe may be larger than 0 degree and less than 45 degrees and an angle θ between the first end  241  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe may be larger than 45 degrees and less than 90 degrees. 
         [0060]    Alternatively, at least the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section has substantially a shape of a curve or arc, or is substantially curved; or the protruded wall section  24  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section has substantially a shape of a curve or arc, or is substantially curved. The middle portion  24   a  extends from the first end  241  to the second end  242  in the axial direction of the refrigerant guiding pipe  10 . 
         [0061]    An angle between a tangent of a surface of at least the middle portion  24   a  of the protruded wall section  24  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  (which is referred to as “an angle between at least the middle portion  24   a  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10 ”) gradually decreases from the first end  241  of the protruded wall section  24  to the second end  242  of the protruded wall section  24  opposite to the first end  241 ; or an angle between a tangent of a surface of the protruded wall section  24  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  (which is referred to as “an angle between the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10 ”) may gradually decrease from the first end  241  of the protruded wall section  24  to the second end  242  of the protruded wall section  24  opposite to the first end  241 . 
         [0062]    At the middle portion  24   a  of the protruded wall section  24 , an angle β between a tangent of a surface of the second end  242  of the protruded wall section  24  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  (which is referred to as “an angle between the second end  242  of the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10 ”) may be larger than 0 degree and less than 45 degrees, and an angle θ between a tangent of a surface of the first end  241  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  (which is referred to as “an angle between the first end  241  and the axial direction of the refrigerant guiding pipe  10 ”) may be larger than 45 degrees and less than 90 degrees; or at the protruded wall section  24 , an angle β between a tangent of a surface of the second end  242  of the protruded wall section  24  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  may be larger than 0 degree and less than 45 degrees, and an angle θ between a tangent of a surface of the first end  241  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10  may be larger than 45 degrees and less than 90 degrees. 
         [0063]    Referring to  FIG. 1 , the refrigerant guiding pipe  10  may be designed such that the above angles θ and β of at least some or all of the protruded wall sections  24  may gradually increase in the direction directed from the end  31  of the refrigerant guiding pipe  10  to be connected to refrigerant piping to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 . 
         [0064]    It may facilitate decrease of resistance to refrigerant flowing through the opening to configure the protruded wall section  24  in a shape of an arc or an arc-like shape. In addition, if refrigerant flows outwards from the inner chamber  19 , i.e., the refrigerant guiding pipe  10  is used as a distributor, when the refrigerant flows through the opening  11   a,  the refrigerant is firstly brought into contact with the second end  242  of the protruded wall section  24 , then flows along the surface of the protruded wall section  24 , and finally flows out from the first end  241  of the protruded wall section  24 . When the angle β is larger than 0 degree and less than 45 degrees, less resistance loss is generated when refrigerant flows through the opening, and when the angle θ is larger than 45 degrees and less than 90 degrees, a better effect of guiding and distributing refrigerant can be achieved. 
         [0065]    An angle between a part of the curved refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10  is defined by an angle between a tangent line or surface of a surface of the part of the refrigerant guiding wall portion facing the opening and the axial direction of the refrigerant guiding pipe  10 . 
         [0066]    It can be appreciated from the above embodiments of the protruded wall section  24 : 
         [0067]    At least the middle portion  24   a  of the refrigerant guiding wall portion, such as the protruded wall section  24 , in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe, the section has a shape of a substantially straight line or is substantially straight, and the middle portion  24   a  is inclined at an angle γ with respect to the axial direction of the refrigerant guiding pipe  10 . Alternatively, the refrigerant guiding wall portion such as the protruded wall section  24  has a section along the axial direction of the refrigerant guiding pipe, the section has a shape of a substantially straight line or is substantially straight, and the refrigerant guiding wall portion such as the protruded wall section  24  is inclined at an angle γ with respect to the axial direction of the refrigerant guiding pipe  10 . The angle γ is about more than 0 degree and less than 90 degrees, desirably in the range from about 5 degrees to about 75 degrees. The distances or pitches d 1  between the adjacent openings  11   a  and between the adjacent openings  11   b  may gradually decrease in the direction directed from the end  31  of the refrigerant guiding pipe  10  to be connected to refrigerant piping to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 ; and at least the middle portions  23   a  (see, e.g.,  FIGS. 9 ,  10  and  12 ) and  24   a  of at least some or all of the refrigerant guiding wall portions in the direction perpendicular to the axial direction of the refrigerant guiding pipe, or at least some or all of refrigerant guiding wall portions are inclined at the angles γ with respect to the axial direction of the refrigerant guiding pipe  10 , and the inclination angles γ may gradually increase in the direction directed from the end  31  of the refrigerant guiding pipe  10  to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 . 
         [0068]    Alternatively, at least the middle portion  24   a  of the refrigerant guiding wall portion in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of a plurality of substantially straight line-shaped segments or a plurality of substantially straight segments, or the section has substantially a shape of a curve or arc or is substantially curved; or the refrigerant guiding wall portion has a section along the axial direction of the refrigerant guiding pipe  10 , and the section is composed of a plurality of substantially straight line-shaped segments or a plurality of substantially straight segments, or the section has substantially a shape of a curve or arc or is substantially curved. The middle portion  24   a  extends from the first end  241  to the second end  242  in the axial direction of the refrigerant guiding pipe  10 . 
         [0069]    In an embodiment, at least the middle portion  24   a  of the refrigerant guiding wall portion in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  has a section along the axial direction of the refrigerant guiding pipe  10 , and the section comprises at least one of at least one substantially straight line-shaped segment and at least one substantially curve-shaped segment; or the refrigerant guiding wall portion has a section along the axial direction of the refrigerant guiding pipe, and the section comprises at least one of at least one substantially straight line-shaped segment and at least one substantially curve-shaped segment. 
         [0070]    An angle between at least the middle portion  24   a  of the refrigerant guiding wall portion, such as the protruded wall section  24 , in the direction perpendicular to the axial direction of the refrigerant guiding pipe  10  and the axial direction of the refrigerant guiding pipe  10  (including an angle between the tangent of the surface of the middle portion  24   a  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10 ) may gradually increase in a direction in which the refrigerant guiding wall portion, such as the protruded wall section  24 , extends outside the inner chamber  19  of the refrigerant guiding pipe  10  from a side of the inner chamber  19  of the refrigerant guiding pipe  10 ; or an angle between the refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe  10  (including an angle between the tangent of the surface of the refrigerant guiding wall portion, such as the protruded wall section  24 , facing the opening  11   a  and the axial direction of the refrigerant guiding pipe  10 ) may gradually increase in a direction in which the refrigerant guiding wall portion, such as the protruded wall section  24 , extends outside the inner chamber  19  of the refrigerant guiding pipe  10  from a side of the inner chamber  19  of the refrigerant guiding pipe  10 . 
         [0071]    At at least the middle portion  24   a  of the refrigerant guiding wall portion, such as the protruded wall section  24 , an angle β between the second end  242 , which is close to the axis  15  of the refrigerant guiding pipe  10 , of the refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe (including the angle between the tangent of the surface of the second end  242  facing the opening  11   a  and the axial direction of the refrigerant guiding pipe) may be larger than 0 degree and less than 45 degrees, and an angle θ between the first end  241 , which is located far from the axis  15 , of the refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe (including the angle between the tangent of the surface of the first end  241  facing the opening and the axial direction of the refrigerant guiding pipe) may be larger than 45 degrees and less than 90 degrees. Alternatively, at the refrigerant guiding wall portion, such as the protruded wall section  24 , an angle β between the second end  242 , which is close to the axis  15  of the refrigerant guiding pipe  10 , of the refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe (including the angle between the tangent of the surface of the second end  242  facing the opening and the axial direction of the refrigerant guiding pipe) may be larger than 0 degree and less than 45 degrees, and an angle θ between the first end  241 , which is located far from the axis  15 , of the refrigerant guiding wall portion such as the protruded wall section  24  and the axial direction of the refrigerant guiding pipe (including the angle between the tangent of the surface of the first end  241  facing the opening and the axial direction of the refrigerant guiding pipe) may be larger than 45 degrees and less than 90 degrees. 
         [0072]    The refrigerant guiding pipe  10  may be designed such that the above angles θ and β of at least some of the refrigerant guiding wall portions such as the protruded wall sections  24  and recessed wall sections  23  (see, e.g.,  FIGS. 9 ,  10  and  12 ) or all of the refrigerant guiding wall portions such as the protruded wall sections  24  may gradually increase in the direction directed from the end  31  of the refrigerant guiding pipe  10  to be connected to a refrigerant piping to the other opposite end  33  of the refrigerant guiding pipe  10 , that is, from the end  31  to the other end  33 . 
         [0073]      FIGS. 6   a  and  6   b  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. The structure of the refrigerant guiding pipe  10  according to this embodiment may employ the features of the refrigerant guiding pipe  10  according to any one of the embodiments of  FIG. 2-5  except as described below. As illustrated in  FIGS. 6   a ,  6   b  and  6   c , a first end  241  of a refrigerant guiding wall portion  26  in a circumferential direction of the refrigerant guiding pipe is separated from the pipe wall  17 , and a second opposite end  242  of the refrigerant guiding wall portion  26  is connected with the pipe wall  17 . The protruded wall section  24  is substantially rectangular in shape. In the embodiment, the entire protruded wall section  24  may be located substantially in one plane. In other words, the entire protruded wall section  24  may have a shape of a substantially flat plate. Alternatively, a section of the protruded wall section  24  in a direction directed from the second end  242  to the first end  241  comprises at least one substantially straight line-shaped segment and/or at least one substantially curve-shaped segment. 
         [0074]      FIGS. 7   a ,  7   b  and  7   c  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. The refrigerant guiding pipe  10  according to this embodiment differs from that of the refrigerant guiding pipe  10  of  FIG. 6  in that all of the first ends  241  and the second ends  242  of the protruded wall sections  24  are not positioned on the same side in a circumferential direction of the refrigerant guiding pipe  10 . Rather, the protruded wall sections  24  with the second ends  242  located on a first side in the circumferential direction of the refrigerant guiding pipe  10  and the protruded wall sections  24  with the second ends  242  located on a second side opposite to the first side in the circumferential direction of the refrigerant guiding pipe  10  are alternately arranged along the axial direction of the refrigerant guiding pipe  10 . 
         [0075]      FIGS. 8   a ,  8   b  and  8   c  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. As illustrated in  FIGS. 8   a ,  8   b  and  8   c , a protruded wall section  24  is substantially rectangular in shape in  FIGS. 8   b  and  8   c , and ends  241  and  242  of the protruded wall section  24  opposite to each other in the axial direction of the refrigerant guiding pipe  10  are separated from the pipe wall  17  to form openings  11   a  opposite to each other in the axial direction, and ends  243  and  244  of the protruded wall section  24  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10  are connected with the pipe wall  17 . A section of the protruded wall section  24  in the circumferential direction of the refrigerant guiding pipe may have substantially the shape of an arch. A section of the protruded wall section  24  in a direction directed from the first end  241  to the second end  242  comprises at least one substantially straight line-shaped segment and/or at least one substantially curve-shaped segment. Alternatively, the middle portion  24   a  of the protruded wall section  24  in the direction perpendicular to the axial direction of the refrigerant guiding pipe may have a substantially U-shaped or V-shaped section along the axial direction of the refrigerant guiding pipe. The middle portion  24   a  extends from the first end  241  to the second end  242  in the axial direction of the refrigerant guiding pipe  10 . 
         [0076]      FIGS. 9   a ,  9   b  and  9   c  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. As illustrated in  FIGS. 9   a ,  9   b  and  9   c , the refrigerant guiding pipe  10  comprises a recessed wall section  23 , the recessed wall section  23  is substantially rectangular in shape in  FIGS. 9   b  and  9 C, and ends  231  and  232  of the recessed wall section  23  opposite to each other in the axial direction of the refrigerant guiding pipe  10  are separated from the pipe wall  17  to form openings  11   b  opposite to each other in the axial direction, and ends  233  and  234  of the recessed wall section  23  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10  are connected with the pipe wall  17 . A section of the recessed wall section  23  in the circumferential direction of the refrigerant guiding pipe may have substantially the shape of an arch. A section of the recessed wall section  23  in a direction directed from the first end  231  to the second end  232  comprises at least one substantially straight line-shaped segment and/or at least one substantially curve-shaped segment. Alternatively, the middle portion  23   a  of the recessed wall section  23  in the direction perpendicular to the axial direction of the refrigerant guiding pipe may have a substantially inverted U-shaped or inverted V-shaped section along the axial direction of the refrigerant guiding pipe. The middle portion  23   a  extends from the first end  231  to the second end  232  in the axial direction of the refrigerant guiding pipe  10 . 
         [0077]      FIGS. 10   a,    10   b  and  10   c  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. As illustrated in  FIGS. 10   a ,  10   b  and  10   c , the refrigerant guiding pipe  10  comprises a recessed wall section  23 , and the recessed wall section  23  is substantially rectangular in shape in  FIGS. 10   b  and  10   c . Ends  231  and  232  of the recessed wall section  23  opposite to each other in the axial direction of the refrigerant guiding pipe  10  are connected with the pipe wall  17 , and ends  233  and  234  of the recessed wall section  23  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10  are separated from the pipe wall  17  to form openings  11   b  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10 . The recessed wall section  23  may have a substantially U-shaped or V-shaped section along the axial direction of the refrigerant guiding pipe. 
         [0078]      FIGS. 11   a,    11   b  and  11   c  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. As illustrated in  FIGS. 11   a,    11   b  and  11   c,  the refrigerant guiding pipe  10  comprises a protruded wall section  24 , and the protruded wall section  24  is substantially quadrangular in shape in  FIGS. 11   b  and  11   c.  Ends  241  and  242  of the protruded wall section  24  opposite to each other in the axial direction of the refrigerant guiding pipe  10  are connected with the pipe wall  17 , and ends  243  and  244  of the protruded wall section  24  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10  are separated from the pipe wall  17  to form openings  11   a  opposite to each other in the circumferential direction of the refrigerant guiding pipe  10 . The protruded wall section  24  may have a substantially inverted U-shaped or inverted V-shaped section along the, axial direction of the refrigerant guiding pipe. 
         [0079]      FIGS. 12   a  and  12   b  show a refrigerant guiding pipe  10  according to an embodiment of the present invention. The structure of the refrigerant guiding pipe  10  according to this embodiment may be substantially the same as that of the refrigerant guiding pipe  10  according to  FIGS. 2-5  except as described below. 
         [0080]    As illustrated in  FIGS. 12   a  and  12   b , the refrigerant guiding pipe  10  comprises a protruded wall section  24  projected outside the inner chamber  19 , and a recessed wall section  23  depressed towards the inner chamber  19 . At least a first end  241  of the protruded wall section  19  in the axial direction of the refrigerant guiding pipe  10  and a first end  231  of the recessed wall section  23  in the axial direction of the refrigerant guiding pipe  10  are separated from each other, thereby forming the opening  11   ab.  Alternatively, the first end  241  of the protruded wall section  24  and the first end  231  of the recessed wall section  23  may be spaced from each other by a predetermined distance prior to processing the protruded wall section  24  and the recessed wall section  23 , and at least the first end  241  of the protruded wall section  24  in the axial direction of the refrigerant guiding pipe  10  is separated from the pipe wall  17 , thereby forming the opening  11   ab,  and at least the first end  231  of the recessed wall section  23  in the axial direction of the refrigerant guiding pipe  10  is separated from the pipe wall  17 , thereby forming the opening  11   ab.    
         [0081]    In the above embodiments, at least the first ends  241  and  231  are separated from the pipe wall  17 , or the first ends  241  and  231  are separated from each other. Alternatively, at least a part of edge of the protruded wall section  24  and at least a part of edge of the recessed wall section  23  may be separated from the pipe wall  11 , or at least a part of edge of the protruded wall section  24  and at least a part of edge of the recessed wall section  23  may be separated from each other. 
         [0082]    The protruded wall section  24  and the recessed wall section  23  according to the above embodiments constitute examples of the refrigerant guiding wall portion. 
         [0083]    In the above embodiments, refrigerant flows along the inner chamber of the refrigerant guiding pipe, and the refrigerant guiding wall portion mainly functions to guide the refrigerant. Refrigerant is ejected to the inner cavity of the manifold along the refrigerant guiding wall portion, and mixed in the manifold so that gaseous refrigerant and liquid refrigerant are uniformly mixed and do not layer. 
         [0084]    The structures described in the above embodiments may be appropriately combined to form new embodiments. Features in one embodiment may also be applicable to the other embodiments or substitute for those of the other embodiments. For example, the protrusion described in  FIG. 6  may be applied to the other embodiments. 
         [0085]    Although the embodiments of the present invention have been described with reference to the drawings, the embodiments shown in the drawings are intended to illustrate the preferable embodiments of the present invention and shall not be construed to limit the present invention. 
         [0086]    For example, the opening and the refrigerant guiding wall portion such as the protruded wall section and the recessed wall section have symmetrical structures in the above embodiments. Alternatively, the opening and the refrigerant guiding wall portion such as the protruded wall section and the recessed wall section may have asymmetrical structures in the above embodiments. For example, when the refrigerant guiding pipe is made of a circular pipe, the opening and the refrigerant guiding wall portion such as the protruded wall section and the recessed wall section may be symmetrical or asymmetrical about a plane passing through a center axis of the refrigerant guiding pipe. 
         [0087]    In addition, in the above embodiments, the examples of the refrigerant guiding wall portion are the protruded wall section and/or the recessed wall section. However, the refrigerant guiding wall portion is not limited to the protruded wall section and/or the recessed wall section. Refrigerant passing through the opening may be guided in other appropriate ways. For example, a separate refrigerant guiding wall portion such as a guide pipe and a guide element may be soldered to the refrigerant guiding pipe in the vicinity of the opening, or to an inside or outside of the refrigerant guiding pipe to guide refrigerant passing through the opening. In addition, the opening may have any appropriate shape and the refrigerant guiding wall portion may have any appropriate shape and structure. 
         [0088]    Furthermore, in the above embodiments, the end of the refrigerant guiding wall portion is separated from the pipe wall, thereby forming the opening. However, the present invention is not limited to this. Alternatively, the refrigerant guiding wall portion may be separated from the pipe wall at any position, thereby forming the opening; or the refrigerant guiding wall portion may be separated from the pipe wall at any edge of the refrigerant guiding wall portion, thereby forming the opening. 
         [0089]    In addition, the refrigerant guiding wall portion may have any appropriate shape such as a semicircular shape or a triangular shape.