Abstract:
A refrigerant distributor for a heat exchanger is disclosed. The refrigerant distributor comprises: a pipe for distributing a refrigerant, the pipe having a channel therein in which the refrigerant flows. The channel has at least one portion having reduced cross-section area. With the above configuration, the distributor relieves the layering of refrigerant flowing in a distributing pipe and mixes the vapor-liquid refrigerant relatively uniformly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is entitled to the benefit of and incorporates by reference essential subject matter disclosed in Chinese Patent Application No. 200910132009.7 filed on Apr. 3, 2009. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a refrigerant distributor for a heat exchanger and a heat exchanger having the refrigerant distributor. 
     2. Description of the Related Art 
     A conventional micro-channel heat exchanger  20  generally comprises micro-channels or flat tubes  5 , fins  4  disposed between the adjacent micro-channels or flat tubes  5 , an inlet manifold  3  and an outlet manifold (not shown) disposed at ends of the micro-channels or flat tubes  5  respectively, and a refrigerant distributor  10  disposed in the inlet manifold  3  as shown in  FIGS. 1-2 . The refrigerant distributor  10  is disposed at a side of the heat exchanger  20  to distribute refrigerant. The distributor  10  may have a portion extending out of the inlet manifold  3  as shown in  FIG. 1  or may have no portion extending out of the inlet manifold  3 . The refrigerant distributor  10  comprises a pipe  9 ′ in which a plurality of outlets  8  are formed in an axial direction of the pipe  9 ′. 
     If vapor-liquid phase refrigerant exists, distribution of the refrigerant shall be problematic. In order to distribute the vapor-liquid phase refrigerant, a refrigerant distributor  10  has been proposed as shown in  FIG. 2 . The distributor  10  is formed by a cylindrical pipe in which a plurality of outlets  8  are formed through a wall of the cylindrical pipe. Assuming that refrigerant enters into the distributor  10  from an inlet  7  shown in  FIG. 2 , the refrigerant flows along an inner chamber of the distributor, is ejected out of the pipe  9 ′ through the outlets  8 , and then is mixed in the inlet manifold  3 . After that, the mixed refrigerant flows into the flat tubes  5 . However, the distributor  10  illustrated in  FIG. 2  is disadvantageous in that refrigerant is layered when it flows in the distributing pipe. The liquid refrigerant is located on a lower side and the gaseous refrigerant is located on an upper side due to the gravity. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a refrigerant distributor for a heat exchanger and a heat exchanger having the refrigerant distributor which can alleviate the layering of refrigerant flowing in a distributing pipe. 
     In accordance with an aspect of the present invention, there is provided a refrigerant distributor for a heat exchanger. The refrigerant distributor comprises: a pipe for distributing refrigerant. The pipe has a channel therein in which the refrigerant flows. The channel has at least one portion having reduced cross-section area, for example, between a first end and a second end of the pipe. 
     In accordance with another aspect of the present invention, the at least one portion having reduced cross-section area is a reducing segment formed by reducing a size of the pipe in a direction generally perpendicular to an axial direction of the pipe. The pipe may be a cylindrical pipe and the reduced size is a diameter. 
     In accordance with a further aspect of the present invention, the at least one portion having reduced cross-section area is a flat segment formed by pressing the portion of the pipe to be flat. 
     In accordance with a still further aspect of the present invention, the at least one portion having reduced cross-section area is a reducing segment formed by pressing an outer peripheral surface of the portion of the pipe. 
     In accordance with a further aspect of the present invention, the at least one portion having reduced cross-section area is formed by a raised portion projecting inward from an inner wall of the pipe. 
     In accordance with another aspect of the present invention, the pipe has an inlet disposed at an end of the pipe and the refrigerant flows into the pipe through the inlet. The at least one portion having reduced cross-section area comprises a plurality of portions having reduced cross-section area. Distances between the adjacent portions having reduced cross-section area of the plurality of portions having reduced cross-section area gradually increase from one end to the other end of the pipe. 
     In accordance with another aspect of the present invention, the at least one portion having reduced cross-section area comprises a plurality of portions having reduced cross-section area. Distances between the adjacent portions having reduced cross-section area of the plurality of portions having reduced cross-section area are generally equal. 
     In accordance with another aspect of the present invention, at least one outlet is disposed between every two adjacent portions having reduced cross-section area of the plurality of portions having reduced cross-section area such that the refrigerant flows out of the pipe through the at least one outlet. In accordance with an alternative aspect of the present invention, the pipe has a plurality of outlets through which the refrigerant flows out of the pipe, the at least one portion having reduced cross-section area comprises a plurality of portions having reduced cross-section area, and a plurality of the portions having reduced cross-section area such as two portions having reduced cross-section area are disposed between every two adjacent outlets of the plurality of outlets. 
     In accordance with another aspect of the present invention, there is provided a heat exchanger. The heat exchanger comprises a refrigerant distributor disposed at a side of the heat exchanger to distribute refrigerant, wherein the refrigerant distributor is one of the distributors mentioned above. The heat exchanger may be a micro-channel heat exchanger. 
     With the above configuration, the refrigerant distributor alleviates the layering of refrigerant flowing in a distributing pipe and mixes the vapor-liquid refrigerant relatively uniformly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawing. 
         FIG. 1  is a schematic view showing a conventional micro-channel heat exchanger. 
         FIG. 2  is a schematic view showing a conventional refrigerant distributor. 
         FIG. 3  is a schematic view showing a micro-channel heat exchanger according to a first embodiment of the present invention. 
         FIG. 4  is a schematic front view showing a refrigerant distributor according to the first embodiment of the present invention. 
         FIG. 5  is a schematic top view of the refrigerant distributor shown in  FIG. 4 . 
         FIG. 6  is a schematic perspective view of the refrigerant distributor shown in  FIG. 4 . 
         FIG. 7  is a schematic view showing a micro-channel heat exchanger according to a second embodiment of the present invention. 
         FIG. 8  is a schematic front view showing a refrigerant distributor according to the second embodiment of the present invention. 
         FIG. 9  is a schematic top view of the refrigerant distributor shown in  FIG. 8 . 
         FIG. 10  is a schematic perspective view of the refrigerant distributor shown in  FIG. 8 . 
         FIGS. 11-13  are schematic views showing a refrigerant distributor according to further embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The embodiments are described below in order to explain the present invention, but do not pose a limitation on the scope of the invention. 
     Embodiment 1 
     A micro-channel heat exchanger  2  according to a first embodiment of the present invention comprises micro-channels or flat tubes  5 , fins  4  disposed between the adjacent micro-channels or flat tubes  5 , an inlet manifold  3  and an outlet manifold (not shown) disposed at ends of the micro-channels or flat tubes  5  respectively, and a refrigerant distributor  1  disposed in the inlet manifold  3  as shown in  FIGS. 3-6 . The refrigerant distributor  1  is disposed at a side of the heat exchanger  2  to distribute refrigerant. 
     The refrigerant distributor  1  for the heat exchanger comprises a pipe  9  for distributing refrigerant as shown in  FIGS. 3-6 . The pipe  9  has a channel  91  therein in which the refrigerant flows. The channel  91  has at least one portion having reduced cross-section area  6 . The pipe  9  may be a cylindrical pipe. The pipe  9  further comprises a plurality of outlets  8  from which the refrigerant flows out of the pipe  9 , and an inlet  7  through which the refrigerant flows into the pipe  9 . At least one outlet  8  is disposed between every two adjacent portions having reduced cross-section area  6  of the plurality of portions having reduced cross-section area  6 . Alternatively, one portion having reduced cross-section area  6 , or a plurality of the portions having reduced cross-section area  6  such as two portions having reduced cross-section area are disposed between every two adjacent outlets  8  of the plurality of outlets  8 . 
     The portions having reduced cross-section area  6  may be reducing segments  6  formed by reducing a size of the pipe  9  in a direction generally perpendicular to an axial direction of the pipe  9  as shown in  FIGS. 3-6 . The portions having reduced cross-section area  6  may be the reducing segments  6  formed by pressing an outer peripheral surface of the portions of the pipe  9 . For example, a diameter D 2  of segments of a cylindrical pipe  9  positioned at intervals in a longitudinal direction of the cylindrical pipe  9  is reduced to a predetermined diameter D 1  to form the reducing segments  6  as an example of the portions having reduced cross-section area, that is, D 2 &lt;D 1 . The outlets  8  are arranged through walls of the unreduced portions of the pipe  9 . 
     Assuming that refrigerant enters into the distributor  1  through the inlet  7 , the refrigerant is remixed every time it passes through one of the reducing segments  6 . As a result, the vapor-liquid refrigerant is mixed uniformly. A part of the mixed refrigerant is passed out of the pipe  9  through the outlets  8  in the unreduced portions of the pipe  9 , and the remaining refrigerant continues advancing and is remixed again when flowing through the next reducing segment. The refrigerant is mixed multiple times through the reducing segments to be more uniformly distributed. 
     In order that a vapor-liquid fluid flowing in the pipe  9  is sufficiently mixed before it arrives at the next outlet  8 , two or more portions having reduced cross-section area  6  may be disposed between every two adjacent outlets  8  to remix the vapor-liquid fluid multiple times such that the vapor-liquid fluid is mixed uniformly when it flows out of the pipe through the outlets  8 . 
     According to an example of the embodiment of the present invention, distances between the adjacent portions having reduced cross-section area may gradually increase from one end of the pipe, at which the inlet  7  is disposed, to the other end of the pipe, or the distances between the adjacent portions having reduced cross-section area may be generally equal. When a refrigerant passes through the reducing segments  6  in a refrigerant flow direction R in which the refrigerant flows in the pipe  9 , pressure loss occurs. As shown in  FIG. 4 , the distances d 1 , d 2 , and d 3  between the adjacent reducing segments may be given as d 3 ≧d 2 ≧d 1 . In other words, the distances become larger in the refrigerant flow direction, thereby reducing large pressure loss that is caused by excessive reducing segments through which the refrigerant passes due to excessive length of a distributor. The number of the reducing segments is not limited and may be determined according to actual conditions. Alternatively, the reducing segments may be arranged at generally equal intervals, that is, the distances d 1 , d 2 , and d 3  between the adjacent reducing segments may be given as d 1 =d 2 =d 3 . 
     An example of a method of manufacturing the distributor is described below. Openings with a predetermined size as the outlets  8  are formed by punching at intervals through a wall of a common smooth cylindrical pipe. Then, reducing segments  6  are formed by pressing an outer peripheral surface of the cylindrical pipe at predetermined positions between the adjacent openings in such a way that a size of a cross-section of the pipe located at the predetermined positions is reduced to a required size. 
     The number of outlets  8  in each of the unreduced portions between the adjacent reducing segments  6  is not limited to one, but two or more outlets  8  may be disposed in each of the unreduced portions between the adjacent reducing segments  6 . The specific positions of the openings may be any appropriate positions and are dependent upon specific conditions. 
     In the above embodiment, alternatively, the pipe may be a pipe having an elliptical cross-section, a flat pipe and the like instead of a cylindrical pipe. A cross-section shape of the pipe is not limited. The pipe may have any appropriate cross-section shape. In addition, the pipe is not limited to a straight pipe, but may be a pipe having any appropriate shape. 
     The cylindrical pipe  9  shown in  FIGS. 4-6  does not contain the portion extending out of the heat exchanger  2  as shown in  FIG. 3 . 
     Embodiment 2 
     A heat exchanger  2 ′ according to a second embodiment of the present invention is the same as that of the first embodiment except a refrigerant distributor V. Only the distributor  1 ′ is described below in detail. 
     The refrigerant distributor  1 ′ comprises a cylindrical pipe  9  as shown in  FIGS. 7-10 . The pipe  9  comprises a plurality of outlets  8  through which the refrigerant flows out of the pipe  9 . The distributor  1 ′ according to the second embodiment is the same as the distributor  1  according to the first embodiment except that the flat segments  6 ′ provided as an example of the portions having reduced cross-section area according to the second embodiment is different from the reducing segments  6  of the first embodiment. The portions having reduced cross-section area  6 ′ are flat segments  6 ′ formed by pressing the portions of the pipe to be flat. The flat segments  6 ′ facilitate manufacturing of the distributor and may be formed in a flat duckbill shape as shown in  FIGS. 7-10 . 
     The cylindrical pipe  9  shown in  FIGS. 8-10  does not contain the portion extending out of the heat exchanger  2 ′ as shown in  FIG. 7 . 
     Although the embodiments in which the distributor according to the present invention is used in the micro-channel heat exchanger have been described, the distributor according to the present invention can be applied to any other appropriate heat exchangers except of the micro-channel heat exchanger. 
     In addition, the embodiments have been described and shown for the purpose of explanation of the present invention, but should not be construed as limitation to the present invention. For example, distributors  1 ″ according to further embodiments may be configured as shown in  FIGS. 11-13 , and the portions having reduced cross-section area of the distributors  1 ″ may be formed by raised portions  6 ″ projecting inward from an inner wall of the pipe  9  as shown in  FIGS. 11-13 . Each raised portion  6 ″ may be formed at a complete inner perimeter of the inner wall of the pipe or at a part of the inner perimeter. For example, a wall of a pipe partially projects inward at a part of an outer perimeter of the pipe instead of the wall of the pipe projecting inward at the complete outer perimeter of the pipe. In addition, the portions having reduced cross-section area according to the present invention may be formed in other manners to generate turbulent flow of refrigerant or to mix refrigerant. 
     In the above embodiments, at least one portion having reduced cross-section area is located between both ends of the pipe. Alternatively, the portion having reduced cross-section area may be positioned at the end of the pipe where the inlet  7  is disposed, such that refrigerant supplied to the distributor through a piping can be mixed uniformly. 
     In addition, in the above embodiments, the portion having reduced cross-section area is described for mixing and distributing refrigerant. However, the portion having reduced cross-section area may be used to generate turbulent flow of refrigerant instead of distribution of refrigerant, or to mix refrigerant. 
     In addition, in  FIGS. 3 and 7 , the outlets  8  are disposed towards a direction perpendicular to the flat tubes  5  only for the purpose of illustration. However, the outlets  8  may be disposed towards any appropriate direction relative to the flat tubes  5 .