Abstract:
A regenerative heat exchanger includes a pair of heat exchangers, an inlet valve assembly and an outlet valve assembly. Each valve assembly includes two corresponding pairs of valve ports and two poppet discs each being movable between said corresponding pairs of valve ports. The poppet discs have rods extending to distal ends. Distal ends extending from the inlet valve assembly are pivotably interconnected to distal ends from the outlet valve assembly and pivotably interconnected to a crank of an eccentric mechanical drive to operate one of the inlet poppet discs and one of the outlet poppet discs in tandem.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The subject invention relates generally to a regenerative heat exchanger assembly. 
         [0003]    2. Description of the Prior Art 
         [0004]    Known regenerative heat exchanger assemblies used to transfer heat energy from a dirty airstream to a clean airstream. One example of a known regenerative heat exchanger assemblies includes a heat wheel divided into pie shaped segments. The heat wheel rotates and alternately passes over hot dirty gases, and cold clean gases. To prevent cross contamination, sliding seals are used. 
       SUMMARY OF THE INVENTION AND ADVANTAGES 
       [0005]    The invention provides for such a regenerative heat exchanger assembly including a first heat exchanger having a plurality of first heat recovery media, and a second heat exchanger having a plurality of second heat recovery media. An inlet valve assembly and an outlet valve assembly are in fluid communication with the first and second heat exchangers. The inlet valve assembly has two corresponding pairs of inlet valve ports, and two inlet poppet discs each being movable between one of the corresponding pairs of inlet valve ports. The outlet valve assembly has two corresponding pairs of outlet valve ports, and two outlet poppet discs each being movable between one of the corresponding pairs of outlet valve ports. A first inlet rod extends from one of the inlet poppet discs to a first inlet distal end, and a first outlet rod extends from one of the outlet poppet discs to a first outlet distal end. An eccentric mechanical drive includes a first crank for rotation about an axis and a first linkage assembly connected to the first crank for orbital movement about the axis. The first linkage assembly interconnects the first inlet distal end to the first outlet distal end to operate one of the inlet poppet discs and one of the outlet poppet discs in tandem. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0007]      FIG. 1  is a schematic view of a periodic regenerative heat exchanger in accordance with an exemplary embodiment of the present invention; 
           [0008]      FIG. 2  is a front view of an eccentric mechanical drive in isolation; 
           [0009]      FIG. 3  is a schematic view of the periodic regenerative heat exchanger showing a first and a second flow path; and 
           [0010]      FIG. 4  is a schematic view of the periodic regenerative heat exchanger showing a third and a fourth flow path. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a regenerative heat exchanger assembly is generally shown at  20 . The regenerative heat exchanger assembly  20  includes a first heat exchanger  22  having a plurality of first heat recovery media  24 , and a second heat exchanger  26  having a plurality of second heat recovery media  28 . The first and second heat recovery media  24 ,  28  could include any suitable material for receiving and transferring heat from one gas stream to another, including, for example, stacked wire mesh, porous ceramic monolith, or a random packed ceramic saddle. The first heat exchanger  22  has a first inlet port  30  and a first outlet port  32 , and the second heat exchanger  26  has a second inlet port  34  and a second outlet port  36 . An inlet valve assembly  38  and an outlet valve assembly  40  in fluid communication with the first and second heat exchangers  22 ,  26  are also provided. 
         [0012]    The inlet valve assembly  38  includes a dirty gas inlet  42  and a clean gas inlet  44 . The dirty gas inlet  42  receives a heated gas stream, such as dirty flue gases in a power plant. The clean gas inlet  44  receives a cool gas stream, such as clean ambient air for use in combustion. Using the regenerative heat exchanger assembly  20  to raise the temperature of the clean ambient air minimizes the amount of virgin fuel needed for combustion. The inlet valve assembly  38  has a left inlet valve area  46  and a right inlet valve area  48  fluidly isolated from one another by an inlet dividing wall  50 . 
         [0013]    An upper left inlet valve port  52  is disposed in the left inlet valve area  46 . An upper left inlet valve seat  54  is disposed around the upper left inlet valve port  52 . A lower left inlet valve port  56  is disposed in the left inlet valve area  46  and is aligned with the upper left inlet valve port  52 . A lower left inlet valve seat  58  is disposed around the lower left inlet valve port  56 . A left discharge port  60  is disposed adjacent to the left inlet valve area  46  and is in fluid communication with the first inlet port  30  of the first heat exchanger  22 . An inlet left poppet disc  62  is disposed in the left inlet valve area  46 . The inlet left poppet disc  62  is movable between the upper left and lower left inlet valve ports  52 ,  56 . A first inlet rod  64  extends from the inlet left poppet disc  62  to a first inlet distal end. 
         [0014]    An upper right inlet valve port  66  is disposed in the right inlet valve area  48 , and an upper right inlet valve seat  68  is disposed around the upper right inlet valve port  66 . A lower right inlet valve port  70  is disposed in the right inlet valve area  48  and is aligned with the upper right inlet valve port  66 . A lower right inlet valve seat  72  is disposed around the lower right inlet valve port  70 . A right discharge port  74  is disposed adjacent to the right inlet valve area  48  and is in fluid communication with the second inlet port  34  of the second heat exchanger  26 . An inlet right poppet disc  76  is disposed in the right inlet valve area  48  and is movable between the upper right and lower right inlet valve ports  66 ,  70 . A second inlet rod  78  extends from the inlet right poppet disc  76  to a second inlet distal end. 
         [0015]    The outlet valve assembly  40  includes a dirty gas outlet  80  and a clean gas outlet  82 . The dirty gas outlet  80  discharges the, then cooled, dirty flue gases from the regenerative heat exchanger assembly  20 . The clean gas outlet  82  directs the, then heated, clean air as needed for combustion. The outlet valve assembly  40  has a left outlet valve area  84  and a right outlet valve area  86  fluidly isolated from one another by an outlet dividing wall  88 . 
         [0016]    An upper left outlet valve port  90  is disposed in the left outlet valve area  84 , and includes an upper left outlet valve seat  92  disposed around the upper left outlet valve port  90 . A lower left outlet valve port  94  is disposed in the left outlet valve area  84  and is aligned with the upper left outlet valve port  90 . A lower left outlet valve seat  96  is disposed around the lower left outlet valve port  94 . A left receiving port  98  is disposed adjacent to the left outlet valve area  84  and is in fluid communication with the first outlet port  32  of the first heat exchanger  22 . An outlet left poppet disc  100  is disposed in the left outlet valve area  84  and is movable between the upper left and lower left outlet valve ports  90 ,  94 . A first outlet rod  102  extends from the outlet left poppet disc  100  to a first outlet distal end. 
         [0017]    An upper right outlet valve port  104  is disposed in the right outlet valve area  86  and includes an upper right outlet valve seat  106  disposed around the upper right outlet valve port  104 . A lower right outlet valve port  108  is disposed in the right outlet valve area  86  and is aligned with the upper right outlet valve port  104 . A lower right outlet valve seat  110  is disposed around the lower right outlet valve port  108 . A right receiving port  112  is disposed adjacent to the right outlet valve area  86  and is in fluid communication with the second outlet port  36  of the second heat exchanger  26 . An outlet right poppet disc  114  is disposed in the right outlet valve area  86  and is movable between the upper right and lower right outlet valve ports  104 ,  108 . A second outlet rod  116  extends from the outlet right poppet disc  114  to a second outlet distal end. 
         [0018]    An eccentric mechanical drive is generally shown at  118 . The eccentric mechanical drive  118  includes a drive shaft  120  extending along an axis between a left end and a right end. The drive shaft  120  supports a first crank  122  at the left end, and a second crank  124 , 180 degrees out of phase with the first crank  122 , is supported at the right end. A motor  126  is provided for rotating the drive shaft  120 , and a controller  128  communicates with the motor  126  to selectively energize the motor  126 . The details of the motor  126  and controller  128  operation are discussed in more detail below. 
         [0019]    A first linkage assembly, generally shown at  130 , is connected to the first crank  122  for orbital movement about the axis. The first linkage assembly  130  interconnects the first inlet distal end of the first inlet rod  64  to the first outlet distal end of the first outlet rod  102 . This allows to operate the inlet left poppet disc  62  in tandem with the outlet left poppet disc  100  by turning the first crank  122 . Thus, when the inlet left poppet disc  62  is sealed against the upper left inlet valve seat  54 , the outlet left poppet disc  100  is sealed against the upper left outlet valve seat  92 . The first linkage assembly  130  includes a first connector  132  pivotably interconnecting the first inlet distal end to the first outlet distal end, and a first pin  134  pivotably interconnecting the first connector  132  to the first crank  122 . 
         [0020]    Likewise, a second linkage assembly, generally shown at  136 , is connected to the second crank  124 . The second linkage assembly  136  interconnects the second inlet distal end to the second outlet distal end to operate the inlet right poppet disc  76  in tandem with the outlet right poppet disc  114 . The second linkage assembly  136  includes a second connector  138  pivotably interconnecting the second inlet distal end to the second outlet distal end, and a second pin  140  pivotably interconnecting the second connector  138  to the second crank  124 . 
         [0021]    A plurality of bushings  142  are provided to guide the first and second inlet rods  64 ,  78  and the first and second outlet rods  102 ,  116 . The bushings  142  are attached to the inlet and outlet valve assemblies  38 ,  40  and surround the rods  64 ,  78 ,  102 ,  116  to provide support for movement along a linear path as the rods  64 ,  78 ,  102 ,  116  translate in response to the eccentric mechanical drive  118 . 
         [0022]    The controller  128  is a variable speed drive that can operate the motor  126  to complete a degree cycle in less than 0.5 seconds. The variable speed drive accelerates the motor  126  for 0.2 seconds, and the decelerates the motor  126  for 0.3 seconds. This timing prevents the poppet discs  62 ,  76 ,  100 ,  114  from contacting their respective valve seats  54 ,  58 ,  68 ,  72 ,  92 ,  96 ,  106 ,  110  with excessive force. As noted earlier, the second crank  124  is out of phase by 180 degrees with the first crank  122 . Thus, when the inlet left poppet disc  62  and the outlet left poppet disc  100  are sealed against the upper left inlet and upper left outlet valve seats  54 ,  92 , the inlet right poppet disc  76  and outlet right poppet disc  114  are sealed against the lower right inlet and lower right outlet valve seats  72 ,  110 . In addition, rotation of the drive shaft  120  has a first rotational position and a second rotational position spaced radially about the drive shaft  120  from the first rotational position by 180 degrees. 
         [0023]    Referring next to  FIG. 3 , when the drive shaft  120  is moved to the first rotational position, the inlet left poppet disc  62  seals against the lower left inlet valve seat  58 , and a first flow path A is thereby defined to move dirty hot gas from the dirty gas inlet  42 , through the upper left inlet valve port  52  and through the left discharge port  60  and into the first heat exchanger  22 . In  FIG. 3 , the first flow path A is identified by the dashed line representing the flow of dirty gas. As the dirty hot gas moves through the first heat exchanger  22 , its heat is transferred to the first heat recovery media  24 , which produces dirty cold gas. With the drive shaft  120  still in the first rotational position, the outlet left poppet disc  100  is sealed against the lower left outlet valve seat  96 , thereby further defining the first flow path A to move the dirty cold gas out of the first heat exchanger  22  and through the left receiving port  98  and through the upper left outlet valve port  90  and out through the dirty gas outlet  80 . 
         [0024]    Simultaneously, with the drive shaft  120  still in the first rotational position, the inlet right poppet disc  76  is sealed against the upper right inlet valve seat  68 , thereby defining a second flow path B to move clean cold gas from the clean gas inlet  44 , through the lower right inlet valve port  70  and through the right discharge port  74 , into the second heat exchanger  26 . In  FIG. 3 , the second flow path B is identified by the solid line representing the flow of clean gas. As the clean cold gas moves through the second heat exchanger  26 , heat stored in the second heat recovery media  28  is transferred to the clean cold gas to produce clean hot gas. With the drive shaft  120  still in the first rotational position, the outlet right poppet disc  114  is sealed against the upper right outlet valve seat  106 . The second flow path B is further defined to move the clean hot gas out of the second heat exchanger  26  and through the right receiving port  112 , through the lower right outlet valve port  108  and out through the clean gas outlet  82 . 
         [0025]    Referring next to  FIG. 4 , the drive shaft  120  is rotated to the second rotational position, where the inlet left poppet disc  62  is now sealed against the upper left inlet valve seat  54 . This position defines to a third flow path C to move clean cold gas from the clean gas inlet  44  through the lower left inlet valve port  56 , through the left discharge port  60  and into the first heat exchanger  22 . In  FIG. 4 , the third flow path C is identified by the solid line representing the flow of clean gas. As the clean cold gas moves through the first heat exchanger  22 , heat that was absorbed by the first heat recovery media  24  in the previous half of the cycle is transferred to the clean cold gas to produce clean hot gas. In addition, the first heat recovery media  24  is now ready to receive additional heat. With the drive shaft  120  still in the second rotational position, the outlet left poppet disc  100  is sealed against the upper left outlet valve seat  92 . This further defines the third flow path C to move the clean hot gas from the first heat exchanger  22 , through the right receiving port  112 , through the lower left outlet valve port  94  and out through the clean gas outlet  82 . 
         [0026]    Simultaneously, while the drive shaft  120  is still in the second rotational position, the inlet right poppet disc  76  is sealed against the lower right inlet valve seat  72  to define a fourth flow path D to move dirty hot gas from the dirty gas inlet  42 , through the upper right inlet valve port  66 , through the right discharge port  74  and into the second heat exchanger  26 . In  FIG. 4 , the fourth flow path D is identified by the dashed line representing the flow of dirty gas. As the dirty hot gas moves through the second heat exchanger  26 , it transfers its heat to the second heat recovery media  28  that was previously cooled in the previous half of the cycle, to produce dirty cold gas. With the drive shaft  120  still in the second rotational position, the outlet right poppet disc  114  is sealed against the lower right outlet valve seat  110 . The fourth flow path D is further defined to move the dirty cold gas out of the second heat exchanger  26 , through the right receiving port  112 , through the upper right outlet valve port  104  and out through the dirty gas outlet  80 . 
         [0027]    This cycle then repeats, with the first and second heat recovery media  24 ,  28  being alternatively heated and cooled by the two gas streams, moving the heat from the dirty gas to the clean gas. Such systems can attain thermal efficiencies as high as 95%. 
         [0028]    Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims.