Patent Publication Number: US-2013233525-A1

Title: Multi-flow passage device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a multi-flow passage device internally formed with a plurality of flow passages through which a medium is passed, like a micro-channel reactor adopted in a heat exchanger or a chemical reaction device. 
     2. Description of the Related Art 
     Conventionally, a heat pump apparatus is used as an apparatus for transferring heat from a lower temperature side to a higher temperature side. The heat pump apparatus is composed of a compressor, a condenser, an expansion valve, an evaporator, and a piping connecting therebetween. In the evaporator or the condenser used in the heat pump apparatus, a heat exchanger (a plate-type heat exchanger) constituted in such a manner that thin heat transfer plates are stacked and a medium is passed through a gap formed between the heat transfer plates, and a heat exchanger constituted by stacking flow passage plates having a plurality of concave grooves as fluid flow passages on the surface can be adopted. Both heat exchangers are multi-flow passage devices internally formed with a plurality of flow passages through which a medium is passed. 
     For example, a multi-flow passage device for heat exchange is disclosed in Japanese Patent Laid-Open No. 60-71894. 
     Japanese Patent Laid-Open No. 60-71894 discloses a multi-flow passage device (a plate type heat exchanger) including a plurality of plates that are abutted via gaskets to form alternate passages for a heat exchange medium therebetween and that include openings for guiding the medium to and from the passages and corrugated portions abutted to each other between the adjacent plates to form supporting points within the passages, in which at least a pair of adjacent plates at each outside end among the plurality of plates are permanently united and joined at their surroundings and around the openings and further at the supporting points between the plates. 
     Meanwhile, conventionally, as shown in Japanese Patent Laid-Open No. 2008-168173, as a method for manufacturing a desired reaction product by contacting liquids (reactants) having solubility to each other and mixing them, a method with the use of a flow passage forming body referred to as a so-called micro-channel reactor is known. The micro-channel reactor includes a substrate formed with grooves on the surface, and the grooves constitute fine flow passages. By passing liquids to be mixed through the fine flow passages, area of contact between the liquids to be mixed per unit volume is dramatically increased, which results in enhancement of mixing efficiency of the liquids to be mixed. 
     As a multi-flow passage device (a micro-channel reactor), Japanese Patent Laid-Open No. 2008-168173 discloses a reaction apparatus for reacting a first reactant and a second reactant while allowing them to flow, including a flow passage structure having therein a flow passage that extends in a specific direction and allows the first reactant and the second reactant to flow in that direction, in which the flow passage includes: a first introduction passage which is arranged at an entrance side of the flow passage and into which the first reactant is introduced; a second introduction passage which is arranged apart from the first introduction passage while sandwiching a partition wall provided in the flow passage structure and into which the second reactant is introduced; a confluent passage connected to the downstream side of the first introduction passage and the second introduction passage for allowing the first reactant flowing through the first introduction passage and the second reactant flowing through the second introduction passage to meet with each other in a mutually separated laminar flow state; and a reaction flow passage connected to the downstream side of the confluent passage for allowing the laminar flow of the first reactant and the laminar flow of the second reactant to flow in the mutual contact state of both reactants and reacting both reactants in the mutual contact interface, and a dimension in a layer thickness direction vertical to the contact interface of the reaction flow passage is set to become smaller than the sum of a dimension in the layer thickness direction of the first introduction passage and a dimension in the layer thickness direction of the second introduction passage. 
     The multi-flow passage devices disclosed in Japanese Patent Laid-Open No. 60-71894 and Japanese Patent Laid-Open No. 2008-168173, although their use applications are different, naturally have a limitation in the number of flow passages and the length of the flow passage in one flow passage plate (plate) constituting an apparatus due to the dimension of the flow passage plate itself and the manufacturing processing method of flow passage. That is, if the number of flow passages per one plate is increased, the length of the flow passage is shortened and a large amount of medium is allowed to pass, but the time during which the medium stays in the multi-flow passage device is reduced, thereby a heat exchange efficiency and a reaction efficiency may be decreased. On the other hand, if the length of the flow passage is lengthened in the plate, the number of flow passages is decreased, so that it may be difficult to pass a large amount of medium. 
     As a countermeasure against that, it is conceivable that a plurality of multi-flow passage devices are connected in series or parallel to perform the necessary treatment. However, the handling of connecting piping is a problem, and there is also a problem in securing an installation space for multi-flow passage devices. Japanese Patent Laid-Open No. 60-71894 and Japanese Patent Laid-Open No. 2008-168173 described above disclose a structure of the multi-flow passage device itself, and disclose no guideline for solving the above problems. 
     Thus, considering the above problems, the present invention has an object to provide a multi-flow passage device capable of surely performing a desired treatment, such as heat exchange or chemical reaction, even to large amounts of medium. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above object, the present invention takes the following technical measures. 
     A multi-flow passage device according to the present invention is constituted by stacking units for performing heat exchange or chemical reaction of the introduced medium in a thickness direction, and a flow passage for allowing the flowing medium in one unit to flow in another unit adjacent to the unit is an external flow passage provided outside of one unit and another unit. 
     The external flow passage may be preferably provided in contact with the side surface of the unit. 
     Inside the external flow passage, a redistribution means for mixing the medium flowing out of one unit and allowing the medium to be redistributed to another unit may be preferably provided. 
     The redistribution means may be preferably composed of a porous plate which is disposed inside the external flow passage so as to intersect with the medium flowing direction and through which the medium is allowed to pass. 
     With the use of the multi-flow passage device of the present invention, a desired treatment can be surely performed, in heat exchange or chemical reaction, even to large amounts of medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view showing that a multi-flow passage device according to the present invention is used as a heat exchanger. 
         FIG. 2  is a schematic view of a structure of the multi-flow passage device according to the present invention. 
         FIGS. 3A and 3B  are plan views of a flow passage plate constituting the multi-flow passage device according to the present invention taken along the line A-A in  FIG. 2 . 
         FIG. 4  is a schematic view showing that the multi-flow passage device according to the present invention is used as a reactor. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, a multi-flow passage device according to the present invention will be described based on the drawings. 
     First Embodiment 
     As a first embodiment, a case where a multi-flow passage device  1  is used as a heat exchanger  2  will be described. 
     Prior to describing the heat exchanger  2 , firstly, a heat pump apparatus  3  will be described as a typical apparatus to which the heat exchanger  2  is mounted. 
     As shown in  FIG. 1 , the heat pump apparatus  3  transfers heat from a lower temperature side to a higher temperature side. The heat pump apparatus  3  includes a compressor  4 , a use-side heat exchanger  2 B, an expansion valve  5 , and an air heat exchanger  2 A, and the compressor  4 , the use-side heat exchanger  2 B, the expansion valve  5 , and the air heat exchanger  2 A are connected by a piping  6 . The piping  6  is a flow passage through which a working medium is cycled. 
     The working medium in the piping  6  absorbs heat by heat transfer from the external air to a refrigerant in the air heat exchanger  2 A, evaporates to be drawn into the compressor  4 , and is compressed therein into a high temperature and pressure gas to be sent to the use-side heat exchanger  2 B. Further, the refrigerant releases heat and turns into liquid in the use-side heat exchanger  2 B, is decompressed by the expansion valve  5  and returns back to the air heat exchanger  2 A, and undergoes a phase change from a liquid to a gas. 
     As for the heat exchanger  2  used as the air heat exchanger  2 A or the use-side heat exchanger  2 B of the above-mentioned heat pump apparatus  3 , high efficiency (high heat-transfer efficiency from the working medium to the use-side medium) is required. However, even if a plurality of heat exchangers  2  are connected in series or parallel to perform the necessary treatment in an effort to increase the efficiency of the heat exchanger  2 , the handling of the piping  6  is a problem and there is also a problem in securing an installation space for the heat exchangers  2  (The details are as described in the above-mentioned “DESCRIPTION OF THE RELATED ART”). 
     Thus, in the present embodiment, the air heat exchanger  2 A and the use-side heat exchanger  2 B are made up of the laminated heat exchanger  2  constituted by stacking heat exchange units  7  for performing heat exchange of the introduced working medium in a thickness direction. Further, a flow passage for allowing the flowing medium in one heat exchange unit  7  to flow in another heat exchange unit  7  adjacent to the heat exchange unit  7  is an external flow passage  8  provided outside of the heat exchange units  7 . 
     Hereinafter, the details of the air heat exchanger  2 A and the use-side heat exchanger  2 B (hereinafter collectively referred to as the heat exchanger  2 ) will be described. 
       FIG. 2  shows a cross section structure of the heat exchanger  2 . 
     The heat exchanger  2  includes four heat exchange units  7  (unit A-unit D) for performing heat exchange of the introduced working medium and the use-side medium, and constituted by stacking these four heat exchange units  7  in a thickness direction (the vertical direction). 
     Various structures can be adopted in each heat exchange unit  7 . For example, it may have a plate type heat exchanger structure. 
     In the plate type heat exchanger  2 , a plurality of heat exchanger plates (heat transfer plates) made of a thin sheet metal such as a stainless plate or an aluminum plate are stacked, and a working medium and a heat source fluid flow alternately between the heat transfer plates, whereby performing heat exchange. On the surface of the heat transfer plate, in order to enhance the heat transfer effect, a herringbone pattern or a corrugated pattern is formed. In the four corners of the heat transfer plate, holes through which the working medium and the heat source are passed are provided. 
     In addition, as the structure of the heat exchange unit  7 , the heat exchanger  2  constituted by stacking flow passage plates  12  having a plurality of concave grooves as fluid flow passages  9  on the surface thereof can be adopted. 
     More specifically, as shown in  FIGS. 3A and 3B , the flow passage plate  12  is a rectangular flat plate having a thickness of several millimeters, for example, made of a metal such as stainless steel or aluminum. At both ends in the longitudinal direction (the horizontal direction in  FIGS. 3A and 3B ) of the flow passage plate  12 , the flow passages  9  are opened at one end along the longitudinal direction as an entrance  10  for the working medium and the flow passages  9  are opened at the other end as an exit  11  for the working medium. The entrance  10  and the exit  11  for the working medium are formed at opposite positions along the longitudinal direction of the flow passage plate  12 . For example, as shown in  FIG. 3A , if the entrance  10  for the working medium is provided in the lower right portion of the flow passage plate  12  in a plan view, the exit  11  for the working medium is provided in the upper left portion of the flow passage plate  12 . In the flow passage plate  12  to be stacked on  FIG. 3A , as shown in  FIG. 3B , the entrance  10  for the working medium is provided in the upper right portion of the flow passage plate  12  in a plan view and the exit  11  for the working medium is provided in the lower left portion of the flow passage plate  12 . Thus, in such a unit structure that the flow passage plates  12  having the entrance  10  and the exit  11  at different positions are stacked alternately, fluids flowing in the respective layers are not mixed. 
     On the surface of the flow passage plate  12 , the plurality of flow passages  9  are formed so as to meander in a width direction of the flow passage plate  12 , and connect the entrance  10  and the exit  11  for the working medium. The plurality of flow passages  9  are formed approximately parallel to each other, and do not intersect with each other. Therefore, the working medium flowing in the flow passage  9  from the entrance  10  reaches the exit  11  by way of only that flow passage  9 . 
     The reason the flow passages  9  meander in the width direction of the flow passage plate  12  is that it is intended to lengthen the flow passages  9  as much as possible within the limited surface. To achieve such purpose, the flow passages  9  may follow the track other than the meandering shape shown in  FIGS. 3A and 3B . 
     The thus configured flow passage plates  12  described above are provided as the flow passage plates  12  for working medium and the flow passage plates  12  for cooling medium (water, air) respectively. Then, the flow passage plates  12  are alternately stacked to form one heat exchange unit  7 . 
     As shown in  FIG. 2 , in case of the present embodiment, a plurality of (four) heat exchange units  7  (also called simply units) described above are provided and stacked in the thickness direction (the vertical direction). Between the respective units  7 , a partition wall plate  13  is disposed in such a manner that the working medium, the use-side medium, and the cooling medium are not mixed. The partition wall plate  13  has the same shape as the heat exchange unit  7  in a plan view. An upper wall plate  16  is provided on the upper surface of the topmost heat exchange unit  7 , and a lower wall plate  17  is provided on the lower surface of the lowermost heat exchange unit  7 . 
     Further, the flow passage  9  for allowing the flowing medium (for example, working medium) in one heat exchange unit  7  to flow in another heat exchange unit  7  adjacent to the heat exchange unit  7  is arranged in the form of the external flow passage  8  provided outside of the heat exchange units  7 . 
     Specifically, an exit side for the working medium of the unit A and an entry side for the working medium of the unit B are set to the same side (the right side in  FIG. 2 ), and an external flow passage  8 AB connecting the two in the vertical direction is provided. Similarly, an exit side for the working medium of the unit B and an entry side for the working medium of the unit C are set to the same side (the left side in  FIG. 2 ), and an external flow passage SBC connecting the two in the vertical direction is provided. Similarly, an exit side for the working medium of the unit C and an entry side for the working medium of the unit D are set to the same side (the right side in  FIG. 2 ), and an external flow passage  8 CD connecting the two in the vertical direction is provided. 
     These external flow passages  8  ( 8 AB,  8 BC,  8 CD) are formed of a rectangular or semicircular sleeve-shaped pipe in a cross-sectional view, and are provided in such a manner that the open side of the semicircular sleeve-shaped pipe is in contact with the side surface of the heat exchange unit  7  (in other words, the side wall of the heat exchanger  2 ). 
     Due to the presence of the external flow passage  8 AB described above, the working medium passed through the unit A is introduced into the unit B placed above the unit A. The working medium passed through the unit B is introduced into the unit C placed above the unit B by way of the external flow passage  8 BC. Subsequently, the working medium passed through the unit C is introduced into the unit D placed above the unit C via the external flow passage  8 CD, and then the working medium discharged from the unit D flows out to the outside of the heat exchanger  2 . 
     Such a heat exchanger  2 , in spite of being compact, can perform heat exchange at high efficiency as is the case where four heat exchange units  7  are connected in series. By increasing the number of stages of the heat exchange units  7 , it is possible to freely extend (set) the length of the flow passage through which the working medium is passed, so that the restriction of the length of the flow passage due to the manufacturing restrictions is eliminated. Therefore, it is possible to secure a desired heat exchange amount. 
     Meanwhile, though the length of the flow passage can be extended by connecting the plurality of heat exchange units  7  via the external flow passages  8 , it is obvious from the experience that the distribution effect in which the working medium is distributed uniformly to the flow passages  9  of the respective units and flows therein is gradually reduced toward the unit at a rear stage. In order to avoid the disadvantage, the use-side heat exchanger  2 B of the present embodiment is provided with a redistribution means  14  for mixing the medium flowing out of one heat exchange unit  7  and allowing the medium to be redistributed to another heat exchange unit  7 , inside the external flow passage  8 . 
     As the redistribution means  14 , in case of the present embodiment, a porous plate  15  which is disposed inside the external flow passage  8  so as to intersect with the medium flowing direction and through which the medium is allowed to pass is adopted. More specifically, the porous plate  15  is a thin sheet provided orthogonal to the flow direction inside the external flow passage  8 , and a plurality of holes are formed in the thin sheet. The shape, the number, the inner diameter, the arrangement pitch or the like of the holes should be determined in consideration of the flow rate and the viscosity of the working medium, and it is preferable that the flow of the working medium is not prevented and the working medium can be stirred and mixed. It should be noted that a mesh structure can be adopted as the redistribution means  14 . 
     Although the porous plate  15  may be provided at any position in the halfway point of the external flow passage  8 , in case of the present embodiment, the porous plate  15  is arranged in the center (the center in the vertical direction) of the flow passage  8 , and one side of the porous plate  15  is fixed in contact with the partition wall plate  13 . It should be noted that in case of a single phase such as gas and liquid, the porous plate  15  may be disposed at the exit  11  or the entrance  10  for the working medium of the heat exchange unit  7 . In addition, for example, when it is desired to distribute a gas-liquid mixed phase flow to the respective flow passages uniformly, the porous plate  15  may be disposed at the entrance  10  for the working medium of the heat exchange unit  7 . 
     The working medium that flows out of one heat exchange unit  7  (for example, the unit A) and flows to the next heat exchange unit  7  (the unit B) is stirred and mixed by passing through the porous plate  15 , and is distributed uniformly to the fluid flow passages  9  formed in the unit B and flows into them. In this manner, in order to obtain further uniformity, after being discharged, fluid is redistributed and uniformly mixed with the use of the porous plate  15  and the like in a header, after that continuing the reaction. Such an action is achieved in all of the porous plates  15 . Therefore, the working medium flows uniformly and heat exchange is performed to a maximum extent in the respective heat exchange units  7 , so that maximum efficiency as the use-side heat exchanger  2 B can be obtained. 
     Second Embodiment 
     Next, as a second embodiment, a case where the multi-flow passage device  1  is used as a micro-channel reactor  20  will be described. 
     The micro-channel reactor  20  includes flow passage plates  12  formed with the flow passages  9  in a bellows-shape on the surface as shown in  FIGS. 3A and 3B , and is constituted by stacking a plurality of flow passage plates  12  in a thickness direction. The flow passages  9  formed on the flow passage plates  12  are referred to as micro-channels in the technical field of the present embodiment, and they are fine flow passages around  1  millimeter in width. The flow passages  9  referred to as micro-channels is formed by using etching techniques such as chemical etching and the like, and its depth is around 0.4-0.6 times the flow passage width. 
     By passing liquids to be mixed through the fine flow passages  9  within the micro-channel reactor  20 , area of contact between the liquids to be mixed per unit volume is dramatically increased, which results in enhancement of mixing efficiency of the liquids to be mixed. 
       FIG. 4  shows a liquid mixing apparatus  21  according to the present embodiment. The apparatus mixes a first and a second liquids having solubility to each other, and includes a micro-channel reactor  20  for mixing, a first liquid supply part  22  for supplying the first liquid to the micro-channel reactor  20 , and a second liquid supply part  23  for supplying the second liquid to the micro-channel reactor  20 . 
     Even as for such a micro-channel reactor  20  included in the liquid mixing apparatus  21 , the structures shown in  FIGS. 2 ,  3 A and  3 B can be adopted. That is, the flow passage  9  for allowing the flowing medium in one reaction unit  24  (corresponding to the heat exchange unit  7  of the first embodiment) to flow in another reaction unit  24  adjacent to the reaction unit  24  is the external flow passage  8  provided outside of the reaction units  24 . Inside the external flow passage  8 , the redistribution means  14 , composed of the porous plate  15  and the like, for mixing the medium flowing out of one reaction unit  24  and allowing the medium to be redistributed to another reaction unit  24  is provided. 
     According to the thus configured micro-channel reactor  20 , in spite of being compact, can perform chemical reaction at high efficiency as is the case where four reaction units  24  are connected in series. By increasing the number of stages of the reaction units  24 , it is possible to freely extend (set) the length of the flow passage through which the first liquid and the second liquid are passed, so that the restriction of the length of the flow passage due to the manufacturing restrictions is eliminated. Therefore, it is possible to achieve a desired chemical reaction. 
     It should be considered that the embodiments disclosed herein are exemplary and not restrictive in all respects. Specifically, in the embodiments disclosed herein, the matters not explicitly disclosed, such as the running condition and the operating condition, the various parameters, the dimension, weight, volume of the components and the like, do not depart from the scope ordinarily implemented by those of skill in the art, and the values that can be readily contemplated by those of ordinary skill in the art are adopted.