Fin for a finned pack for heat exchangers as well as a heat exchanger

Abstract

The present invention regards a fin for a finned pack for heat exchangers, including a plate in which a plurality of through holes is formed for the positioning of tubes intended to convey a first heat exchange fluid, the plate having an edge as well as two main faces, each intended to be licked by a second heat exchange fluid in a crossing direction (A-A) from an inlet portion to an outlet portion of the edge of the plate.

1 . A fin for a finned pack for heat exchangers, comprising a plate in which a plurality of through holes is obtained for the positioning of tubes intended to convey a first heat exchange fluid, said plate having an edge as well as two main faces each intended to be licked by a second heat exchange fluid in a crossing direction (A-A) from an inlet portion to an outlet portion of said edge of said plate, said holes being delimited by a respective inner delimiting wall of said plate including a first portion facing towards said inlet portion and a second portion facing towards said outlet portion, said fin comprising at least one confinement unit of said second fluid arranged around a hole of said plurality of holes so as to obtain at least one partially surrounded hole, said at least one confinement unit comprising two baffles or two through recesses for housing baffles arranged one opposite the other with respect to a respective partially surrounded hole as well as each surrounding and spaced from a respective section of said second portion of said delimiting wall of said partially surrounded hole, so as to confine, during use, on said plate a first flow zone (FZ 1 ) of said second fluid between each baffle or recess and a respective section of said second portion of said delimiting wall,
 wherein said first flow zone (FZ 1 ) has section, evaluated with reference to a plane orthogonal to said plate and passing through the center or central point of the respective partially surrounded hole, that is constant for the entire extension thereof,   constant and then diverging,   converging for the entire extension thereof,   converging and then diverging,   constant and then converging, or   constant, then converging and finally diverging,   and wherein the intrados of said baffles or said recesses along said first flow zone (FZ 1 ), i.e. the section of said baffles or recesses facing towards or facing the respective partially surrounded hole, comprises a curved or substantially curved surface with concavity facing towards said first flow zone (FZ 1 ) at the areas with constant and/or converging section of said first flow zone (FZ 1 ), and a curved or substantially curved surface with concavity facing away from said first flow zone (FZ 1 ) itself at the optional areas with diverging section of said first flow zone (FZ 1 ).   
     
     
         2 . The fin according to  claim 1 , wherein said first flow zone (FZ 1 ) does not have first areas with section, evaluated with reference to a plane orthogonal to said plate and passing through the center of the respective partially surrounded hole, greater than areas downstream and upstream of said first areas. 
     
     
         3 . The fin according to  claim 1 , wherein by identifying, in a plane orthogonal to the symmetry axis x-x of a partially surrounded hole, an initial angle between an initial axis (S 0 ) parallel to said crossing direction (A-A) and passing through the center or a central point of the partially surrounded hole and a first axis (S 1 ) which extends from the center or central point of the partially surrounded hole to the inlet portion of a baffle or recess, said initial angle is between 45° and 135°, preferably between 80° and 100°. 
     
     
         4 . The fin according to  claim 3 , wherein by identifying, in a plane orthogonal to the symmetry axis (x-x) of a partially surrounded hole, a first angle between a first axis (S 1 ) which extends from the center or a central point of the partially surrounded hole to the first end of a baffle or recess and a second axis (S 2 ) which extends from the center of the partially surrounded hole to the point of such baffle or recess defining the termination or end of said section constant, the first angle is between 45° and 135°. 
     
     
         5 . The fin according to  claim 4 , wherein said first angle has a value between the value of the initial angle and 100°. 
     
     
         6 . The fin according to  claim 1 , wherein if said section of said first flow zone (FZ 1 ) is constant and then converging or constant, then converging and finally diverging, by identifying in a plane orthogonal to the symmetry axis (x-x) of the partially surrounded hole a second angle between a second axis (S 2 ) which extends from the center of the partially surrounded hole to the point of a baffle or recess defining the termination or the end of the constant section and a third axis (S 3 ) which extends from the center of the partially surrounded hole to the point of such baffle or recess defining the termination or the end of the converging section, said second angle is between 45° and 180°,
 whereas if the section of said first flow zone (FZ 1 ) is converging for the entire extension thereof or converging and then diverging, by identifying in the plane orthogonal a second angle between a second axis (S 2 ) which extends from the center of the partially surrounded hole to the point of a baffle or recess defining the first end of a baffle or recess and a third axis (S 3 ) which extends from the center of the partially surrounded hole to the point of such baffle or recess defining the termination or the end of the converging section, the second angle is between 45° and 180°, preferably between 45° and 150°. 
 
     
     
         7 . The fin according to  claim 4 , wherein said section is constant and then converging or constant, then converging and finally diverging, and wherein said second angle has a value comprised between the value of said first angle and 150°. 
     
     
         8 . The fin according to  claim 4 , wherein if said section is constant and then diverging, by identifying in a plane orthogonal to the symmetry axis (x-x) of the partially surrounded hole a third angle between a second axis (S 2 ) which extends from the center of the partially surrounded hole to the point of a baffle or recess defining the termination or the end of the section constant and a fourth axis (S 4 ) which extends from the center of the partially surrounded hole to the point of such baffle or recess defining the termination of the diverging section, the third angle is between 45° and 180°, whereas if the section is converging and then diverging or constant, then converging and finally diverging, by identifying in a plane orthogonal to the symmetry axis (x-x) of the partially surrounded hole a third angle between a third axis (S 3 ) which extends from the center of the partially surrounded hole to the point of a baffle or recess defining the termination of the converging section and a fourth axis (S 4 ) which extends from the center of the partially surrounded hole to the point of such baffle or recess defining the termination of the diverging section, the third angle is between 45° and 180°. 
     
     
         9 . The fin according to  claim 4 , wherein said section is constant and then diverging, wherein said third angle has a value comprised between the value of said first angle and 165°. 
     
     
         10 . The fin according to  claim 1 , wherein said baffles or said housing recesses are extended beyond a respective partially surrounded hole, i.e. said baffles or said housing recesses have terminal sections closer to said outlet portion with respect to a respective partially surrounded hole and defining a second flow zone (FZ 2 ) constituting a continuation of said first flow zone (FZ 1 ), said second flow zone (FZ 2 ) not extending around said partially surrounded hole, said second flow zone (FZ 2 ) having a supply mouth corresponding to the dispensing mouth of said first flow zone (FZ 1 ) as well as a discharge mouth for said second fluid towards parts of said fin subsequent in the direction of said crossing direction (A-A), said second flow zone (FZ 1 ) having a section, evaluated with reference to a plane orthogonal to said plate and passing through the center of the respective partially surrounded hole, that is diverging. 
     
     
         11 . The fin according to  claim 1 , wherein the baffles or the housing recesses of a respective confinement unit have a first end proximal to said inlet portion, a second end distal from said inlet portion of said plate and wherein the distance between said baffles or said recesses in the direction moving away from the inlet portion initially progressively decreases and then, once a minimal value has been reached at an intermediate portion of said baffles or recesses, progressively increases once again up to said second end. 
     
     
         12 . The fin according to  claim 1 , wherein extrados of said baffles or said recesses, i.e. the section of said baffles or said recesses facing away from the respective partially surrounded hole, is substantially rectilinear or slightly curved and does not have depression or stagnation zones for said second fluid. 
     
     
         13 . The fin according to  claim 12 , wherein said extrados is substantially tilted with respect to said crossing direction (A-A) for an angle between −45° and 45°, with an initial end proximal to said inlet portion and distal from said outlet portion and a final end distal from said inlet portion and proximal to said outlet portion, the initial ends of the extrados of the baffles or recesses of a partially surrounded hole being situated at a distance from each other greater than the distance between the final ends of the extradoses of such baffles or recesses. 
     
     
         14 . The fin according to  claim 12 , wherein each baffle or recess of said at least one confinement unit has intrados that is not parallel to the respective extrados, i.e. the section of the baffles or recesses facing away from the respective partially surrounded hole. 
     
     
         15 . The fin according to  claim 1 , wherein said baffles or recesses have a configuration, with reference to the travel direction of said second fluid on said plate, with a first section with constant width, a second section with increasing width and then a third section with decreasing width. 
     
     
         16 . The fin according to  claim 1 , wherein said baffles have a substantially tubular structure so as to delimit at least one first opening or channel. 
     
     
         17 . The fin according to  claim 16 , wherein said at least one first opening or channel is substantially extended parallel to the symmetry axis (x-x) of the respective hole and is set to allow the passage through the respective baffle and in a direction substantially parallel to said symmetry axis (x-x) of a third fluid or of said first fluid or is set to be arranged in communication with the outside. 
     
     
         18 . The fin according to  claim 15 , wherein said first opening is delimited at said second and said third section or at said first, said second and said third section. 
     
     
         19 . The fin according to  claim 16 , wherein said baffles comprise a tubular body with substantially constant thickness. 
     
     
         20 . The fin according to  claim 1 , wherein said baffles comprise at least one drawn portion of the plate, i.e. said baffles are obtained by means of drawing of said plate. 
     
     
         21 . The fin according to  claim 20 , wherein said at least drawn portion of said plate is tapered moving away from the main extension plane of said plate, such that said at least one drawn portion has a free end or tip with lower width than its base or end for constraining to the plate. 
     
     
         22 . A finned pack for a heat exchanger, comprising:
 a plurality of fins according to  claim 1  arranged in succession one after the other and substantially parallel to each other, each fin having its through holes aligned with the through holes of the other fins;   a introduction opening for introducing a second fluid between pairs of fins of said plurality of fins, said fins having their inlet portions at said introduction opening;   an outlet opening for said second fluid between said pairs of fins, said fins having their outlet portions at said outlet opening;   a plurality of tubes fitted in the aligned through holes of said plurality of fins, said tubes having a first sector facing towards said inlet opening as well as a second sector facing towards said outlet opening; and   
       said fins having a confinement unit around a portion of a second sector of at least one of said tubes. 
     
     
         23 . The finned pack according to  claim 22 , wherein said tip of the drawn portions of a plate is fitted in the base or better yet in the opening defined by the base of the drawn portions of an adjacent and successive fin. 
     
     
         24 . A heat exchanger with finned pack comprising at least one finned pack according to  claim 22 . 
     
     
         25 . The fin according to  claim 8 , wherein said section is converging and then diverging or constant, then converging and finally diverging, and wherein said third angle has a value comprised between the value of said second angle and 165°.