Patent Publication Number: US-2019195563-A1

Title: Heat exchange device and heat source machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Japan application serial no. 2017-248716, filed on Dec. 26, 2017. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to a heat exchange device and a heat source machine, and more particularly to a heat exchange device having a primary heat exchanger and a secondary heat exchanger and a heat source machine having the same. 
     Description of Related Art 
     Conventionally, a heat exchange device including a primary heat exchanger for recovering sensible heat and a secondary heat exchanger for recovering latent heat has been proposed. This heat exchange device is described in, for example, Japanese Laid-open No. 2017-211173 (Patent Document 1). In the heat exchange device described in this publication, the secondary heat exchanger has a plurality of heat absorbing pipes. The plurality of heat absorbing pipes are arranged vertically. Each of the plurality of heat absorbing pipes extends in a zigzag manner in a forward and backward direction. 
     In the heat exchange device described in the above publication, since each of the plurality of heat absorbing pipes extends in a zigzag manner in the forward and backward direction (horizontal direction), drainage performance is poor when water is discharged from the heat absorbing pipes. Further, since a combustion gas flowing from the primary heat exchanger into the secondary heat exchanger first comes into contact with the uppermost heat absorbing pipe among the plurality of heat absorbing pipes, the uppermost heat absorbing pipe reaches the highest temperature. Therefore, scale (boiler scale) precipitated due to minerals contained in water tends to accumulate in the uppermost heat absorbing pipes more than in the heat absorbing pipes located below the uppermost heat absorbing pipe. As a result, a balance in distribution of water between the plurality of heat absorbing pipes deteriorates. 
     SUMMARY 
     A heat exchange device of an embodiment of the disclosure is a heat exchange device which is capable of recovering sensible heat and latent heat of a combustion gas. The heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger is for recovering the sensible heat of the combustion gas. The secondary heat exchanger is disposed to overlap the primary heat exchanger in a vertical direction in a state in which the heat exchange device is installed and is for recovering the latent heat of the combustion gas. The secondary heat exchanger includes a plurality of first pipes, and a plurality of second pipes each alternately adjacent to each of the plurality of first pipes in a direction intersecting the vertical direction. Each of the plurality of first pipes and the plurality of second pipes has a plurality of linear portions and a plurality of curved portions connecting the plurality of linear portions with each other and extends in a zigzag manner in the vertical direction by the plurality of linear portions being connected to the plurality of curved portions in series. Each of the plurality of linear portions of each of the plurality of second pipes is disposed to be displaced from one of the plurality of linear portions of one of the plurality of first pipes in the vertical direction. 
     A heat source machine of an embodiment of the disclosure includes the above-described heat exchange device, and a burner. The burner is disposed on a side of the primary heat exchanger opposite to the secondary heat exchanger. The burner is formed to be able to supply the combustion gas in the order of the primary heat exchanger and the secondary heat exchanger. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  a diagram schematically showing a configuration of a heat source machine according to an embodiment of the disclosure. 
         FIG. 2  is a perspective view schematically showing a configuration of a heat exchange device according to the embodiment of the disclosure. 
         FIG. 3  is a side view showing an internal structure of the heat exchange device according to the embodiment of the disclosure with a broken line. 
         FIG. 4  is a perspective view schematically showing a configuration of a secondary heat exchanger according to the embodiment of the disclosure. 
         FIG. 5  is an exploded perspective view schematically showing the configuration of the secondary heat exchanger according to the embodiment of the disclosure. 
         FIG. 6  is a top view schematically showing the configuration of the secondary heat exchanger according to the embodiment of the disclosure. 
         FIG. 7  is a rear view showing the internal structure of the heat exchange device according to an embodiment of the disclosure with a broken line. 
         FIG. 8  is a cross-sectional view taken along line VIII-VIII of  FIG. 2 . 
         FIG. 9  is a cross-sectional view taken along line IX-IX of  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The embodiments of the disclosure provide a heat exchange device capable of improving drainage performance and improving the balance of distribution of water and a heat source machine including the same. 
     A heat exchange device of an embodiment of the disclosure is a heat exchange device which is capable of recovering sensible heat and latent heat of a combustion gas. The heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger is for recovering the sensible heat of the combustion gas. The secondary heat exchanger is disposed to overlap the primary heat exchanger in a vertical direction in a state in which the heat exchange device is installed and is for recovering the latent heat of the combustion gas. The secondary heat exchanger includes a plurality of first pipes, and a plurality of second pipes each alternately adjacent to each of the plurality of first pipes in a direction intersecting the vertical direction. Each of the plurality of first pipes and the plurality of second pipes has a plurality of linear portions and a plurality of curved portions connecting the plurality of linear portions with each other and extends in a zigzag manner in the vertical direction by the plurality of linear portions being connected to the plurality of curved portions in series. Each of the plurality of linear portions of each of the plurality of second pipes is disposed to be displaced from one of the plurality of linear portions of one of the plurality of first pipes in the vertical direction. 
     According to the heat exchanger of one or some exemplary embodiments of the disclosure, each of the plurality of first pipes and the plurality of second pipes extends in the zigzag manner in the vertical direction by the plurality of linear portions being connected to the plurality of curved portions in series. Therefore, when water is discharged from each of the plurality of first pipes and the plurality of second pipes, the water drains from an upper side to a lower side due to gravity, and thus drainage performance can be improved. Further, since the secondary heat exchanger is disposed to overlap the primary heat exchanger in the vertical direction in the state in which the heat exchange device is installed, the combustion gas flows into the secondary heat exchanger in the vertical direction. Since the plurality of first pipes and the plurality of second pipes are disposed in a direction intersecting the vertical direction, each of the plurality of first pipes and each of the plurality of second pipes comes into contact with the combustion gas uniformly. Therefore, scale (boiler scale) is deposited uniformly in each of the plurality of first pipes and each of the plurality of second pipes. Therefore, it is possible to prevent a balance in distribution of the water from deteriorating in each of the plurality of first pipes and the plurality of second pipes. That is, the balance in distribution of the water can be improved. Further, each of the plurality of linear portions of each of the plurality of second pipes is disposed to be displaced from each of the plurality of linear portions of each of the plurality of first pipes in the vertical direction. Therefore, it is possible to reduce flow path resistance when the combustion gas flows in the vertical direction between each of the plurality of linear portions of each of the plurality of first pipes and each of the plurality of linear portions of each of the plurality of second pipes. 
     In the above-described heat exchanger, the primary heat exchanger includes a plurality of fin pipes. Each of the plurality of fin pipes extends in a direction in which the plurality of linear portions extend. Therefore, the combustion gas flows between each of the plurality of first pipes and each of the plurality of second pipes along a flow of combustion gas flowing between the plurality of fin pipes. Thus, it is possible to reduce the flow path resistance when the combustion gas flows from the primary heat exchanger to the secondary heat exchanger in the vertical direction. 
     In the above-described heat exchanger, the secondary heat exchanger comprises a circumferential wall portion surrounding the plurality of first pipes and the plurality of second pipes. The circumferential wall portion comprises a main body portion and an expanded portion which expands outward from the main body portion. Each of the plurality of first pipes and each of the plurality of second pipes are disposed in an inner space of the circumferential wall portion surrounded by the main body portion and an inner space of the circumferential wall portion expanded due to the expanded portion. Therefore, the main body portion can be made smaller than the expanded portion. In addition, since the plurality of first pipes and the plurality of second pipes are disposed in the inner space of the circumferential wall portion expanded due to the expanded portion, a heat transfer area of the plurality of first pipes and the plurality of second pipes can be increased as compared with a case in which the expanded portion is not provided. Thus, it is possible to improve heat exchange efficiency of the plurality of first pipes and the plurality of second pipes while the main body portion is miniaturized. 
     A heat source machine of an embodiment of the disclosure includes the above-described heat exchange device, and a burner. The burner is disposed on a side of the primary heat exchanger opposite to the secondary heat exchanger. The burner is formed to be able to supply the combustion gas in the order of the primary heat exchanger and the secondary heat exchanger. According to the heat source machine according to one or some exemplary embodiments of the disclosure, it is possible to provide a heat source machine including a heat exchange device capable of improving the drainage performance and improving the balance in distribution of the water. 
     As described above, according to the embodiments of the disclosure, it is possible to provide a heat exchange device capable of improving drainage performance and improving a balance in distribution of water and a heat source machine including the same. 
     Hereinafter, embodiments of the disclosure will be described below with reference to the drawings. 
     First, referring to  FIG. 1 , a configuration of a heat source machine  100  according to an embodiment of the disclosure will be described. 
     As shown in  FIG. 1 , the heat source machine  100  according to the embodiment mainly includes a spark plug  1 , a primary heat exchanger (sensible heat recovery heat exchanger)  10 , a secondary heat exchanger (latent heat recovery heat exchanger)  20 , a burner  30 , a chamber  31 , a blowing device  32 , a duct  33 , a venturi  34 , an orifice  35 , a gas valve  36 , a pipe  40 , a bypass pipe  41 , a three-way valve  42 , and a housing  50 . The primary heat exchanger  10  and the secondary heat exchanger  20  form a heat exchange device  200 . All of the above components except for the housing  50  are disposed inside the housing  50 . The above-mentioned components are the same as those in the related art except for the heat exchange device  200 . 
     A fuel gas flows to the venturi  34  through the gas valve  36  and the orifice  35 . A mixed gas mixed by the venturi  34  is delivered to the blowing device  32 . The blowing device  32  is for supplying the mixed gas to the burner  30 . The blowing device  32  is connected to the chamber  31 , and the chamber  31  is connected to the burner  30 . The mixed gas supplied from the blowing device  32  is delivered to the burner  30  through the chamber  31 . The burner  30  is for generating a heating gas (combustion gas) which is supplied to the primary heat exchanger  10 . The mixed gas blown out from the burner  30  is ignited by the spark plug  1  and becomes a combustion gas. 
     The burner  30 , the primary heat exchanger  10 , and the secondary heat exchanger  20  are connected so that a combustion gas sequentially passes through the primary heat exchanger  10  and the secondary heat exchanger  20  to exchange heat with hot water. The burner  30  is disposed on a side of the primary heat exchanger  10  opposite to the secondary heat exchanger  20 . The burner  30  is configured to be able to supply the combustion gas in the order of the primary heat exchanger  10  and the secondary heat exchanger  20 . In the embodiment, the burner  30  is disposed above the primary heat exchanger  10 . In other words, the burner  30  is of a reverse combustion type. Further, the burner  30  may be a premix burner of which a capacity fluctuates over an entire region of a combustion chamber frontage. The duct  33  is connected to the secondary heat exchanger  20 , and the duct  33  extends to the outside of the housing  50 . Accordingly, the combustion gas which has passed through the secondary heat exchanger  20  is discharged outside of the housing  50  through the duct  33 . A portion of the pipe  40  on a hot water outlet side from the primary heat exchanger  10  and the bypass pipe  41  are connected by the three-way valve  42 . 
     Next, a configuration of the heat exchange device  200  of the embodiment will be described with reference to  FIGS. 2 to 9 . As shown in  FIGS. 2 and 3 , the heat exchange device  200  is capable of recovering sensible heat and latent heat of the combustion gas. The heat exchange device  200  has the primary heat exchanger  10  and the secondary heat exchanger  20 . The primary heat exchanger  10  is for recovering the sensible heat of the combustion gas. The secondary heat exchanger  20  is for recovering the latent heat of the combustion gas. The primary heat exchanger  10  and the secondary heat exchanger  20  are disposed to overlap in a first direction D 1 . The secondary heat exchanger  20  is disposed to overlap the primary heat exchanger  10  in a vertical direction in a state in which the heat exchange device  200  is installed. That is, in the state in which the heat exchange device  200  is installed, the first direction D 1  is the vertical direction. 
     The primary heat exchanger  10  is connected to the secondary heat exchanger  20 . The combustion gas is supplied through an upper opening of the primary heat exchanger  10 , and the combustion gas is exhausted through a lower opening of the secondary heat exchanger  20 . The hot water entering the secondary heat exchanger  20  from a water inlet portion  20   a  of the secondary heat exchanger  20  exchanges heat with the combustion gas, then exits from a hot water outlet portion  20   b  and enters a water inlet portion  10   a  of the primary heat exchanger  10  via a pipe (not shown). The hot water which has entered the water inlet portion  10   a  of the primary heat exchanger  10  exchanges heat with the combustion gas and then exits from a hot water outlet portion  10   b . The water inlet portion  10   a  is a portion through which the hot water first enters the primary heat exchanger  10 . The hot water outlet portion  10   b  is a portion through which the hot water finally exits from the primary heat exchanger  10 . 
     The primary heat exchanger  10  includes the water inlet portion  10   a , the hot water outlet portion  10   b , a heat exchanging portion  11 , a shell plate  12 , a shell pipe portion  13 , a header member  14 , and a bend pipe  15 . The heat exchanging portion  11  includes a plurality of fins  11   a  and a plurality of fin pipes  11   b . Each of the plurality of fins  11   a  and the plurality of fin pipes  11   b  may be formed of SUS (stainless steel). The heat exchanging portion  11  is configured so that the combustion gas flows outside the plurality of fins  11   a  and the plurality of fin pipes  11   b  and water flows inside the plurality of fin pipes  11   b . The plurality of fins  11   a  are stacked on each other. The plurality of fin pipes  11   b  pass through the plurality of fins  11   a . In  FIGS. 2 and 3 , for convenience of description, only some of the plurality of fins  11   a  are illustrated. 
     The shell plate  12  surrounds the heat exchanging portion  11 . The shell plate  12  includes a front surface portion  12   a , a pair of side surface portions  12   b , and a back surface portion  12   c . The front surface portion  12   a , the pair of side surface portions  12   b , and the back surface portion  12   c  form a square frame. The shell plate  12  has openings at the top and bottom. The shell plate  12  can supply the combustion gas to the inside of the shell plate  12  through the upper opening. The shell plate  12  can exhaust the combustion gas to the outside of the shell plate  12  through the lower opening. 
     The shell pipe portion  13  is disposed along inner surfaces of the pair of side surface portions  12   b  and the back surface portion  12   c  of the shell plate  12 . The shell pipe portion  13  includes a first cooling pipe  131 , a second cooling pipe  132 , and a third cooling pipe  133 . The first cooling pipe  131 , the second cooling pipe  132  and the third cooling pipe  133  are installed side by side in the first direction D 1 . The first cooling pipe  131 , the second cooling pipe  132  and the third cooling pipe  133  are connected in series via the header member  14 . The header member  14  is installed on the front surface portion  12   a  of the shell plate  12 . The header member  14  includes a first header member  141  and a second header member  142 . 
     One end of the first cooling pipe  131  is connected to the water inlet portion  10   a , and the other end of the first cooling pipe  131  is connected to the first header member  141 . One end of the second cooling pipe  132  is connected to the first header member  141 , and the other end of the second cooling pipe  132  is connected to the second header member  142 . One end of the third cooling pipe  133  is connected to the second header member  142  and the other end of the third cooling pipe  133  is connected to the bend pipe  15  disposed on the uppermost side. The plurality of fin pipes  11   b  are connected to each other in series by the bend pipe  15 . 
     As shown in  FIGS. 3 and 4 , the secondary heat exchanger  20  includes the water inlet portion  20   a , the hot water outlet portion  20   b , a heat exchanging portion  21 , a shell plate (circumferential wall portion)  22 , and a header member  23 . The heat exchanging portion  21  includes a plurality of first pipes  21   a  and a plurality of second pipes  21   b . Each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  may be formed of SUS (stainless steel). The heat exchanging portion  21  is formed so that the combustion gas flows outside each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  and the water flows inside the plurality of first pipes  21   a  and the plurality of second pipes  21   b.    
     Each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  is a meandering pipe (meander). The plurality of first pipes  21   a  and the plurality of second pipes  21   b  are alternately folded back in a second direction D 2  orthogonal to the first direction D 1 . Each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  is formed so that the second direction D 2  is a longitudinal direction. The plurality of first pipes  21   a  and the plurality of second pipes  21   b  are stacked on each other in a third direction D 3  orthogonal to both the first direction D 1  and the second direction D 2 . 
     As shown in  FIGS. 4 and 5 , the shell plate  22  surrounds the plurality of first pipes  21   a  and the plurality of second pipes  21   b . The shell plate  22  includes a front surface portion  22   a , a pair of side surface portions  22   b , and a back surface portion  22   c . The front surface portion  22   a , the pair of side surface portions  22   b , and the back surface portion  22   c  form a square frame. The shell plate  22  has openings at the top and bottom. The shell plate  22  can supply the combustion gas to the inside of the shell plate  22  through the upper opening. The shell plate  22  allows the combustion gas to be exhausted outside of the shell plate  22  through the lower opening. The shell plate  22  includes a main body portion  221  and an expanded portion  222 . The expanded portion  222  expands outward from the main body portion  221 . The expanded portion  222  is provided on the front surface portion  22   a . The expanded portion  222  expands from the main body portion  221  toward a side opposite to the back surface portion  22   c.    
     The header member  23  includes a first header member  231  and a second header member  232 . The first header member  231  and the second header member  232  are disposed side by side in the first direction D 1 . The first header member  231  is disposed farther from the primary heat exchanger  10  than the second header member  232  is. The first header member  231  and the second header member  232  are disposed at both ends of the shell plate  22  in the second direction D 2 . Each of the first header member  231  and the second header member  232  is configured to extend in the third direction D 3 . The water inlet portion  20   a  is connected to the first header member  231 . The hot water outlet portion  20   b  is connected to the second header member  232 . 
     As shown in  FIG. 5 , each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  has a plurality of linear portions  21   c  and a plurality of curved portions  21   d . Each of the plurality of linear portions  21   c  extends in the second direction D 2 . Each of the plurality of curved portions  21   d  extends in the third direction D 3 . The plurality of curved portions  21   d  connects the plurality of linear portions  21   c  to each other. Each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  extends in a zigzag manner in the vertical direction (first direction D 1 ) by the plurality of linear portions  21   c  being connected to the plurality of curved portions  21   d  in series. Each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  are disposed not to overlap each other in the vertical direction (the first direction DD. Each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  may have the same shape. 
     As shown in  FIGS. 5 and 6 , one end of each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  is connected to the first header member  231 , and the other end of each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  is connected to the second header member  232 . The plurality of first pipes  21   a  and the plurality of second pipes  21   b  are connected in parallel via the first header member  231  and the second header member  232 . 
     As shown in  FIGS. 6 and 7 , in a state in which the heat exchange device  200  is installed, each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are arranged in a direction (the third direction D 3 ) orthogonal to the vertical direction (the first direction DD. That is, in the state in which the heat exchange device  200  is installed, the third direction D 3  is a horizontal direction. The plurality of first pipes  21   a  and the plurality of second pipes  21   b  are alternately disposed in parallel in the third direction D 3 . In the state in which the heat exchange device  200  is installed, the plurality of second pipes  21   b  alternately adjoin the plurality of first pipes  21   a  in a direction (the third direction D 3 ) intersecting the vertical direction (the first direction DD. Each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  may be alternately brought into contact with each other in the third direction D 3 . 
     Each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  uniformly comes into contact with the combustion gas indicated by a hollow arrow in  FIG. 7 . Therefore, it is minimized that scale (boiler scale) precipitated due to minerals contained in water is locally deposited in each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b . Accordingly, a drift of water flowing through each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  is minimized. 
     Each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  are disposed to be displaced from each other in the first direction D 1 . Each of the plurality of first pipes  21   a  is disposed closer to the primary heat exchanger  10  in the first direction D 1  than each of the plurality of second pipes  21   b . Each of the plurality of first pipes  21   a  comes into contact with the combustion gas indicated by a hollow arrow in  FIG. 7  before each of the plurality of second pipes  21   b.    
     As shown in  FIG. 8 , each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  is disposed in an inner space of the shell plate  22  surrounded by the main body portion  221  and in an inner space of the shell plate  22  expanded due to the expanded portion  222 . Specifically, the plurality of curved portions  21   d  of each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed inside the expanded portion  222 . The plurality of curved portions  21   d  of each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed with a gap between an inner surface of the expanded portion  222  and the curved portions  21   d . The expanded portion  222  is disposed between the first header member  231  and the second header member  232  in the first direction D 1 . 
     As shown in  FIGS. 8 and 9 , each of the plurality of second pipes  21   b  is disposed farther from the primary heat exchanger  10  in the first direction D 1  than each of the plurality of first pipes  21   a . In the state in which the heat exchange device  200  is installed, each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b  is disposed to be displaced from each of the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  in the vertical direction (the first direction DD. In the plurality of first pipes  21   a , one linear portion  21   c  among the plurality of linear portions  21   c  in each of the plurality of second pipes  21   b  is disposed adjacent to a region sandwiched between the linear portions  21   c  adjacent to each other in the vertical direction (the first direction D 1 ) among the plurality of linear portions  21   c  in an intersecting direction (the third direction D 3 ) intersecting with the vertical direction (the first direction D 1 ). 
     In the embodiment, each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b  is disposed between the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  in the vertical direction (the first direction DD. That is, each of the plurality of linear portions  21   c  adjacent to each other in the intersecting direction (the third direction D 3 ) intersecting the vertical direction (the first direction D) of each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed not to overlap each other in the vertical direction (the first direction DD. Also, each of the plurality of fin pipes  11   b  extends in the second direction D 2 . Each of the plurality of fin pipes  11   b  extends in a direction (the second direction D 2 ) in which the plurality of linear portions  21   c  extend. 
     Next, the operation and effects of the embodiment will be described. 
     As shown in  FIG. 8 , according to the heat exchange device  200  of the embodiment, each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  extends in a zigzag manner in the vertical direction (the first direction D 1 ) by the plurality of linear portions  21   c  being connected to the plurality of curved portions  21   d  in series. Therefore, when water is discharged from each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b , the water drains from an upper side to a lower side due to gravity, and thus drainage performance can be improved. 
     Further, as shown in  FIG. 9 , in the state in which the heat exchange device  200  is installed, since the secondary heat exchanger  20  is disposed to overlap the primary heat exchanger  10  in the vertical direction (the first direction D 1 ), the combustion gas indicated by a solid arrow A in  FIG. 9  flows into the secondary heat exchanger  20  in the vertical direction (the first direction DD. Since the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed in the direction (the third direction D 3 ) intersecting the vertical direction (the first direction D 1 ), each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  comes into contact with the combustion gas uniformly. Therefore, the scale is deposited uniformly in each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b . Thus, it is possible to prevent a balance in distribution of the water from deteriorating in each of the plurality of first pipes  21   a  and the plurality of second pipes  21   b . That is, the balance in distribution of the water can be improved. Therefore, failure of the heat exchange device  200  can be minimized. 
     Further, each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b  is disposed to be displaced from each of the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  in the vertical direction (the first direction D 1 ). Therefore, it is possible to reduce flow path resistance when the combustion gas flows in the vertical direction (the first direction D) between each of the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  and each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b . Accordingly, a capacity of the blowing device  32  can be reduced, and thus a power consumption and a size of the blowing device  32  can be reduced. 
     Further, each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b  is disposed between the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  in the vertical direction (the first direction DD. Therefore, even if each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  are in contact with each other in the third direction D 3 , the combustion gas is caused to flow between each of the plurality of linear portions  21   c  of each of the plurality of first pipes  21   a  and each of the plurality of linear portions  21   c  of each of the plurality of second pipes  21   b  in the vertical direction (the first direction D 1 ). 
     As shown in  FIG. 8 , in the heat exchange device  200  of the embodiment, each of the plurality of fin pipes  11   b  extends in a direction (the second direction D 2 ) in which the plurality of linear portions  21   c  extend. Therefore, the combustion gas flows between each of the plurality of first pipes  21   a  and each of the plurality of second pipes  21   b  along the flow of the combustion gas flowing between the plurality of fin pipes  11   b . Thus, it is possible to reduce the flow path resistance when the combustion gas flows from the primary heat exchanger  10  to the secondary heat exchanger  20  in the vertical direction (the first direction D 1 ). 
     As shown in  FIG. 8 , in the heat exchange device  200  of the embodiment, the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed in the inner space of the shell plate  22  surrounded by the main body portion  221  and the inner space of the shell plate  22  expanded due to the expanded portion  222 . Therefore, the main body portion  221  can be made smaller than the expanded portion  222 . Also, since the plurality of first pipes  21   a  and the plurality of second pipes  21   b  are disposed in the inner space of the shell plate  22  expanded due to the expanded portion  222 , a heat transfer area of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  can be increased as compared with a case in which the expanded portion  222  is not provided. In the expanded portion  222 , since heat exchange is performed between the combustion gas indicated by a solid arrow A in  FIG. 8  and the plurality of first pipes  21   a  and the plurality of second pipes  21   b , it is possible to improve a heat exchange amount. Therefore, it is possible to improve heat exchange efficiency of the plurality of first pipes  21   a  and the plurality of second pipes  21   b  while the main body portion  221  is miniaturized. 
     As shown in  FIG. 1 , the heat source machine  100  of the embodiment includes the above-described heat exchange device  200  and the burner  30 . The burner  30  is formed to be able to supply the combustion gas in the order of the primary heat exchanger  10  and the secondary heat exchanger  20 . According to the heat source machine  100  of the embodiment, it is possible to provide the heat source machine  100  including the heat exchange device  200  capable of improving the drainage performance and improving the balance in distribution of the water. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.