Patent Description:
As the heat exchange element of a counterflow type, there is a heat exchange element in which heat transfer plates formed by resin sheets are stacked. For example, Patent Literature <NUM> discloses a heat exchange element formed in a hexagonal column by stacking heat transfer plates having a hexagonal shape. In the heat exchange element of a hexagonal column, a part of a side surface serves as an inlet/outlet port for air for heat exchange. In addition, among edge portions of the heat transfer plates, edge portions other than edge portions facing the side surfaces serving as the inlet/outlet ports for air are joined between the heat transfer plates to be stacked, and leakage of air from the heat exchange element is prevented. The joining of the edge portions is performed by thermal welding or bonding using epoxy.

Patent Literature <NUM>, according to its abstract, relates to a recuperator comprising a number of neighbouring hexagonal sheets which are connected to each other. Flow passages are formed between neighbouring sheets. Each of the sheets, at its periphery, is at least partially surrounded by and connected to an associated connecting body. Neighbouring connecting bodies are connected to each other at at least a part of the periphery of the associated sheets and together form the wall of a housing. Passage openings are provided in the wall which are connected to the flow passages for allowing air into the flow passages via the passage openings. Neighbouring connecting bodies are provided with protruding parts and with recesses respectively on sides facing each other, wherein the forms of the protruding parts and of the recesses adjoin each other in order to connect the connecting bodies to each other by a press fit. Patent Literature <NUM>, on which the preamble of claim <NUM> is based, further provides methods for producing a connecting body and for producing a recuperator.

In recent years, there is a case where ultrasonic welding is used as a method for joining between heat transfer plates. By using ultrasonic welding, it is possible to shorten a time for joining between the heat transfer plates. In ultrasonic welding, ultrasonic vibration is transmitted to an edge portion through a tool sandwiching the edge portion. In the joining between the heat transfer plates using ultrasonic welding, there is a problem that a position of the heat transfer plate is deviated due to the ultrasonic vibration.

The present disclosure has been made in view of the above, and an object of the present invention is to provide a heat exchange element capable of accurately and easily positioning between heat transfer plates without positional deviation, even when the heat transfer plates constituting the heat exchange element are fixed with each other by ultrasonic welding.

According to the present disclosure, a heat exchange element as defined in independent claim <NUM> is provided. Further embodiments of the claimed invention are defined in the dependent claims. Although the claimed invention is only defined by the claims, the below embodiments, examples, and aspects are present for aiding in understanding the background and advantages of the claimed invention.

According to the present disclosure, it is possible to obtain a heat exchange element capable of accurately and easily positioning between heat transfer plates without positional deviation, even when the heat transfer plates constituting the heat exchange element are fixed with each other by ultrasonic welding.

Hereinafter, a heat exchange element according to an embodiment will be described in detail with reference to the drawings.

<FIG> is a perspective view of a heat exchange element according to a first embodiment. <FIG> is an exploded perspective view of the heat exchange element according to the first embodiment. <FIG> is a perspective view in which a part of the heat exchange element according to the first embodiment is extracted. In a heat exchange element <NUM>, a first heat transfer plate <NUM> and a second heat transfer plate <NUM> each having a hexagonal shape are alternately stacked to form a hexagonal column as a whole. Note that, in the following description, a stacking direction of the first heat transfer plate <NUM> and the second heat transfer plate <NUM> is simply referred to as a stacking direction. In addition, a description will be given assuming that a vertical direction on the page of <FIG> is a vertical direction in the heat exchange element <NUM>.

In the heat exchange element <NUM>, one of six side surfaces having a rectangular shape is a first inflow surface <NUM> serving as an inflow port of air into the heat exchange element <NUM>. A side surface facing a direction opposite to the first inflow surface <NUM> is a first outflow surface <NUM> from which air having flowed in from the first inflow surface <NUM> flows out. An air passage <NUM> connecting the first inflow surface <NUM> and the first outflow surface <NUM> is formed inside the heat exchange element <NUM>.

One side surface among two side surfaces adjacent to the first outflow surface <NUM> is a second inflow surface <NUM> serving as an inflow port of air into the heat exchange element <NUM>. A side surface facing a direction opposite to the second inflow surface <NUM> is a second outflow surface <NUM> from which air having flowed in from the second inflow surface <NUM> flows out. The first inflow surface <NUM> and the second outflow surface <NUM> are adjacent to each other. An air passage <NUM> connecting the second inflow surface <NUM> and the second outflow surface <NUM> is formed inside the heat exchange element <NUM>. The air passage <NUM> and the air passage <NUM> do not cross each other inside the heat exchange element <NUM>.

The heat exchange element <NUM> is provided inside a ventilator, for example, and allows an exhaust air flow from inside to outside of a room to pass through the air passage <NUM>, and allows a supply air flow from outside to inside of the room to pass through the air passage <NUM>, so that the heat exchange element <NUM> can cause heat exchange between the supply air flow and the exhaust air flow.

<FIG> is a plan view of a first heat transfer plate according to the first embodiment. The first heat transfer plate <NUM> has a hexagonal shape in plan view. By stacking the first heat transfer plate <NUM> and the second heat transfer plate <NUM>, the air passage <NUM> is formed on one surface side of the first heat transfer plate <NUM>, and the air passage <NUM> is formed on another surface side of the first heat transfer plate <NUM>. The first heat transfer plate <NUM> is provided with a heat exchanger <NUM> that causes heat exchange between air passing through the air passage <NUM> and air passing through the air passage <NUM>. The heat exchanger <NUM> is formed by a rectangular region having, as short sides, sides 1a and 1b facing side surfaces on which the first inflow surface <NUM>, the first outflow surface <NUM>, the second inflow surface <NUM>, and the second outflow surface <NUM> are not formed, among the side surfaces of the heat exchange element <NUM>. Although a structure will not be described in detail, the heat exchanger <NUM> has a corrugated shape having a plurality of irregularities. In the heat exchanger <NUM>, air passing through the air passage <NUM> and air passing through the air passage <NUM> pass in parallel and opposite directions to each other.

The first heat transfer plate <NUM> is provided with a first header 6a having a triangular shape in plan view. The first header 6a includes a side 1c facing the first inflow surface <NUM> and a side 1d facing the second outflow surface <NUM>, in the heat exchange element <NUM>.

The first heat transfer plate <NUM> is provided with a second header 6b having a triangular shape in plan view. The second header 6b includes a side 1e facing the first outflow surface <NUM> and a side 1f facing the second inflow surface <NUM>, in the heat exchange element <NUM>. The first header 6a and the second header 6b are provided on one side and another side with the heat exchanger <NUM> interposed therebetween. The sides 1a and 1b of the first heat transfer plate <NUM> are sides that are not in contact with the first header 6a and the second header 6b.

In the first header 6a and the second header 6b, ribs <NUM> are formed. The rib <NUM> formed in the first header 6a extends from the side 1c toward the heat exchanger <NUM>. The rib <NUM> formed in the first header 6a extends substantially parallel to the side 1d, and allows air having flowed in from the first inflow surface <NUM>, that is, the side 1c side, to smoothly pass toward the heat exchanger <NUM>.

The rib <NUM> formed in the second header 6b extends from the side 1e toward the heat exchanger <NUM>. The rib <NUM> formed in the second header 6b extends substantially parallel to the side 1f, and allows air from the heat exchanger <NUM> to smoothly pass toward the side 1e.

On an outer edge of the first header 6a, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 1c. On an outer edge of the first header 6a, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 1d. In the first heat transfer plate <NUM>, a step <NUM> along the stacking direction is provided between the belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM>, in order to allow inflow of air from the side 1c and prevent inflow of air from the side 1d. More specifically, the belt-shaped flat portion <NUM> is formed at a position below a region where the rib <NUM> is formed, and the belt-shaped flat portion <NUM> is formed at a position above the belt-shaped flat portion <NUM>. Note that the belt-shaped flat portion <NUM> and the region where the rib <NUM> is formed may be formed on one surface.

On an outer edge of the second header 6b, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 1e. On an outer edge of the second header 6b, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 1f. In the first heat transfer plate <NUM>, a step <NUM> along the stacking direction is provided between the belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM>, in order to allow outflow of air from the side 1e and prevent outflow of air from the side 1f. More specifically, the belt-shaped flat portion <NUM> is formed at a position below a region where the rib <NUM> is formed, and the belt-shaped flat portion <NUM> is formed at a position above the belt-shaped flat portion <NUM>. Note that the belt-shaped flat portion <NUM> and the region where the rib <NUM> is formed may be formed on one flat surface.

On an outer edge of the heat exchanger <NUM>, belt-shaped flat portions <NUM> and <NUM> are provided, which are belt-shaped flat regions extending along the side 1a. The belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM> are formed provided with a step <NUM> at an intermediate portion in between in a direction along the side 1a. The belt-shaped flat portion <NUM> is formed above the belt-shaped flat portion <NUM>.

On an outer edge of the heat exchanger <NUM>, belt-shaped flat portions <NUM> and <NUM> are provided, which are belt-shaped flat regions extending along the side 1b. The belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM> are formed provided with a step <NUM> at an intermediate portion in between in a direction along the side 1b. The belt-shaped flat portion <NUM> is formed above the belt-shaped flat portion <NUM>. The first heat transfer plate <NUM> has a point symmetrical shape centered on a center position of the hexagonal shape in plan view.

<FIG> is a plan view of a second heat transfer plate according to the first embodiment. The second heat transfer plate <NUM> has a hexagonal shape in plan view. Configurations similar to those of the first heat transfer plate <NUM> are denoted by identical reference numerals, and a detailed description thereof will be omitted. The second heat transfer plate <NUM> is in a mirror image relationship with the first heat transfer plate <NUM>.

By stacking the first heat transfer plate <NUM> and the second heat transfer plate <NUM>, the air passage <NUM> is formed on one surface side of the second heat transfer plate <NUM>, and the air passage <NUM> is formed on another surface side of the second heat transfer plate <NUM>. The second heat transfer plate <NUM> is provided with the heat exchanger <NUM> that causes heat exchange between air passing through the air passage <NUM> and air passing through the air passage <NUM>. In the second heat transfer plate <NUM>, the heat exchanger <NUM> is formed by a rectangular region having, as short sides, sides 2a and 2b facing side surfaces on which the first inflow surface <NUM>, the first outflow surface <NUM>, the second inflow surface <NUM>, and the second outflow surface <NUM> are not formed, among the side surfaces of the heat exchange element <NUM>.

The second heat transfer plate <NUM> is provided with a third header 6c having a triangular shape in plan view. The third header 6c includes a side 2c facing the first inflow surface <NUM> and a side 2d facing the second outflow surface <NUM>, in the heat exchange element <NUM>.

The second heat transfer plate <NUM> is provided with a fourth header 6d having a triangular shape in plan view. The fourth header 6d includes a side 2e facing the first outflow surface <NUM> and a side 2f facing the second inflow surface <NUM>, in the heat exchange element <NUM>. The third header 6c and the fourth header 6d are provided on one side and another side with the heat exchanger <NUM> interposed therebetween. The sides 2a and 2b of the second heat transfer plate <NUM> are sides not in contact with the third header 6c and the fourth header 6d.

In the third header 6c and the fourth header 6d, the ribs <NUM> are formed. The rib <NUM> formed in the third header 6c extends from the side 2d toward the heat exchanger <NUM>. The rib <NUM> formed in the third header 6c extends substantially parallel to the side 2c, and allows air from the heat exchanger <NUM> to smoothly pass toward the side 2d.

The rib <NUM> formed in the fourth header 6d extends from the side 2f toward the heat exchanger <NUM>. The rib <NUM> formed in the fourth header 6d extends substantially parallel to the side 2e, and allows air having flowed in from the second inflow surface <NUM>, that is, the side 2f side, to smoothly pass toward the heat exchanger <NUM>.

On an outer edge of the third header 6c, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 2c. On an outer edge of the third header 6c, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 2d. In the second heat transfer plate <NUM>, a step <NUM> along the stacking direction is provided between the belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM>, in order to allow outflow of air from the side 2d and prevent outflow of air from the side 2c. More specifically, the belt-shaped flat portion <NUM> is formed at a position below the region where the rib <NUM> is formed, and the belt-shaped flat portion <NUM> is formed at a position above the belt-shaped flat portion <NUM>. Note that the belt-shaped flat portion <NUM> and the region where the rib <NUM> is formed may be formed on one flat surface.

On an outer edge of the fourth header 6d, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 2e. On an outer edge of the fourth header 6d, a belt-shaped flat portion <NUM> is provided, which is a belt-shaped flat region extending along the side 2f. In the second heat transfer plate <NUM>, a step <NUM> along the stacking direction is provided between the belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM>, in order to allow inflow of air from the side 2f and prevent inflow of air from the side 2e. More specifically, the belt-shaped flat portion <NUM> is formed at a position below the region where the rib <NUM> is formed, and the belt-shaped flat portion <NUM> is formed at a position above the belt-shaped flat portion <NUM>. Note that the belt-shaped flat portion <NUM> and the region where the rib <NUM> is formed may be formed on one flat surface.

On an outer edge of the heat exchanger <NUM>, belt-shaped flat portions <NUM> and <NUM> are provided, which are belt-shaped flat regions extending along the side 2a. The belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM> are formed provided with a step <NUM> at an intermediate portion in between in a direction along the side 2a. The belt-shaped flat portion <NUM> is formed above the belt-shaped flat portion <NUM>.

On an outer edge of the heat exchanger <NUM>, belt-shaped flat portions <NUM> and <NUM> are provided, which are belt-shaped flat regions extending along the side 2b. The belt-shaped flat portion <NUM> and the belt-shaped flat portion <NUM> are formed provided with a step <NUM> at an intermediate portion in between in a direction along the side 2b. The belt-shaped flat portion <NUM> is formed above the belt-shaped flat portion <NUM>. The second heat transfer plate <NUM> has a point symmetrical shape centered on a center position of the hexagonal shape in plan view.

Next, a protrusion <NUM>, a base <NUM>, a cone cover <NUM>, and a cone <NUM> formed on the first heat transfer plate <NUM> and the second heat transfer plate <NUM> will be described.

The protrusion <NUM> and the base <NUM> are formed on the headers 6a, 6b, 6c, and 6d. <FIG> is a partially enlarged cross-sectional view in which a protrusion and a base portion in the heat exchange element according to the first embodiment are enlarged. <FIG> is a partially enlarged perspective cross-sectional view in which the protrusion and the base portion in the heat exchange element according to the first embodiment are enlarged. <FIG> is a plan view of the base according to the first embodiment.

The protrusion <NUM> is formed so as to protrude downward. The protrusion <NUM> is a second convex portion. A back surface of the protrusion <NUM> is a recess. Returning to <FIG>, a plurality of protrusions <NUM> are formed along the sides 1c, 1e, 2d, and 2f serving as inlet/outlet ports for air. The plurality of protrusions <NUM> are formed for each of the sides 1c, 1e, 2d, and 2f. The protrusions <NUM> are formed at positions where lengths of the sides 1c, 1e, 2d, and 2f are divided at equal intervals. A ratio of a height of the protrusion <NUM> to a diameter at a root of the protrusion <NUM> is <NUM> or less. With this ratio, when the heat transfer plates <NUM> and <NUM> are formed by vacuum molding, it is possible to prevent a material from becoming too thin and forming a hole.

As illustrated in <FIG>, the base <NUM> is formed so as to protrude upward. A cross-sectional shape of the base <NUM> is trapezoidal shape. A flat region is provided at a top portion of the base <NUM>, and a recess 14a recessed downward is formed in the flat region. As illustrated in <FIG>, a planar shape of the base <NUM> is a rhombus shape. The recess 14a has an elongated hole shape whose longitudinal direction is a direction toward a center of the heat transfer plates <NUM> and <NUM> in plan view. A width along a short direction of the recess 14a is a width in which the protrusion <NUM> is fitted.

The base <NUM> is provided such that a longer diagonal line among two diagonal lines of the rhombus is parallel to the sides 1d, 1f, 2c, and 2e with which the base <NUM> is along. That is, it suffices that the base <NUM> is provided such that the longer diagonal line among the two diagonal lines of the rhombus is along an air flow direction. The base <NUM> is provided as close as possible to the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>, at a position away to such an extent that the base <NUM> does not overlap with the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> with a gap provided in between, on a straight line substantially parallel to the air flow direction. Note that, in the present embodiment, it can also be said that the base <NUM> is disposed on a straight line substantially parallel to the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>.

The protrusion <NUM> and the base <NUM> are formed at positions overlapping with each other in plan view when the first heat transfer plate <NUM> and the second heat transfer plate <NUM> are stacked. As illustrated in <FIG>, when the heat transfer plates <NUM> and <NUM> are stacked, a region serving as a flat surface of a top portion of the base <NUM> abuts on the heat transfer plates <NUM> and <NUM> stacked above. Further, the protrusion <NUM> is fitted into the recess 14a of the base <NUM>. The protrusion <NUM> is fitted into the recess 14a and thus is not exposed to the air passages <NUM> and <NUM>. Note that the protrusion <NUM> may protrude upward, and the base <NUM> may protrude downward.

As illustrated in <FIG>, the cone cover <NUM> is formed on the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> of the heat transfer plates <NUM> and <NUM>. A plurality of cone covers <NUM> are formed for each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>. The cone covers <NUM> are formed at positions where lengths of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> are divided at equal intervals. The cone covers <NUM> are formed at positions closer to the heat exchanger <NUM> than a center in a width direction of each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>.

<FIG> is a partially enlarged cross-sectional view in which a cone cover and a cone portion in the heat exchange element according to the first embodiment are enlarged. <FIG> is a partially enlarged perspective cross-sectional view in which the cone cover and the cone portion in the heat exchange element according to the first embodiment are enlarged. The cone cover <NUM> is a concave portion recessed upward from below. The cone cover <NUM> protrudes on a back surface side of the concave portion. The cone cover <NUM> is formed in a conical shape whose tip end has a flat shape. A ratio of a height of the cone cover <NUM> to a gap distance between the heat exchanger <NUM> and the cone cover <NUM> is <NUM> or less. With this ratio, when the heat transfer plates <NUM> and <NUM> are formed by vacuum molding, it is possible to prevent a material from becoming too thin and forming a hole. The concave portion of the cone cover <NUM> has an elongated hole shape extending in a length direction of each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>.

As illustrated in <FIG>, the cone <NUM> is formed on the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> of the heat transfer plates <NUM> and <NUM>. A plurality of cones <NUM> are formed for each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>. The cones <NUM> are formed at positions where lengths of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> are divided at equal intervals. The cones <NUM> are formed at positions closer to the heat exchanger <NUM> than a center in a width direction of each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>. A ratio of a height of the cone <NUM> to a gap distance between the heat exchanger <NUM> and the cone <NUM> is <NUM> or less. With this ratio, when the heat transfer plates <NUM> and <NUM> are formed by vacuum molding, it is possible to prevent a material from becoming too thin and forming a hole.

As illustrated in <FIG> and <FIG>, the cone <NUM> is a first convex portion protruding upward. The cone <NUM> is formed in a conical shape whose tip end has a curved surface.

When the heat transfer plates <NUM> and <NUM> are stacked, the belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> below. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> above. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> below. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> above. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> below. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> above. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> below. The belt-shaped flat portion <NUM> abuts on the belt-shaped flat portion <NUM> above. As will be described in detail later, the abutting belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> serve as joining edge joined by ultrasonic welding.

The cone cover <NUM> and the cone <NUM> are formed at positions overlapping with each other in plan view when the heat transfer plates <NUM> and <NUM> are stacked. As illustrated in <FIG> and <FIG>, when the heat transfer plates <NUM> and <NUM> are stacked, the cone <NUM> fits into the concave portion of the cone cover <NUM>. Note that the concave portion of the cone cover <NUM> may be recessed downward, and the cone <NUM> may be protruded downward.

Next, a manufacturing process for the heat exchange element will be described. <FIG> is a view illustrating a schematic configuration of a manufacturing device for the heat exchange element according to the first embodiment. The manufacturing device includes a receiving base <NUM> on which the heat transfer plates <NUM> and <NUM> are placed. The receiving base <NUM> has a function of holding the heat transfer plates <NUM> and <NUM> by a method such as suction, and is provided with a hole (not illustrated) for positioning at a location identical to a position of the protrusion <NUM>. Furthermore, on an upper side of the manufacturing device, a guide pin <NUM> and a guide pin <NUM> are included at locations identical to positions of the protrusion <NUM>. <FIG> is a perspective cross-sectional view illustrating a state in which a guide pin illustrated in <FIG> is fitted into the protrusion. The guide pin <NUM> is movable up and down, and a tip end thereof is inserted into a recess on a back surface of the protrusion <NUM> as illustrated in <FIG> when the guide pin <NUM> moves downward. This similarly applies to the guide pin <NUM>.

In the manufacturing process for the heat exchange element <NUM>, stacking and fixing of the first heat transfer plate <NUM> and the second heat transfer plate <NUM> are repeated. <FIG> are views illustrating a manufacturing process for the heat exchange element according to the first embodiment.

In the manufacturing process of the heat exchange element <NUM>, as illustrated in <FIG>, first, the first heat transfer plate <NUM>, which is the first piece of stacking, is placed on the receiving base <NUM>. At this time, the protrusion <NUM> is aligned with the hole of the receiving base <NUM>, so that the protrusion <NUM> is fitted into the hole of the receiving base <NUM> to perform positioning.

Next, as illustrated in <FIG>, a tip end of the guide pin <NUM> is fitted into the concave portion on the back surface of the protrusion <NUM> of the second heat transfer plate <NUM> to be stacked next, and then, as illustrated in <FIG>, the second heat transfer plate <NUM> is stacked. By doing in this manner, the abutting belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are fixed with one another by ultrasonic welding in a state where both the heat transfer plates <NUM> and <NUM> of the upper layer and the lower layer are positioned by the manufacturing device. Next, as illustrated in <FIG>, stacking is performed while positioning is performed using the guide pins <NUM> with respect to the first heat transfer plates <NUM> to be stacked next. In this manner, the first heat transfer plate <NUM> and the second heat transfer plate <NUM> are stacked up to any height by alternately repeatedly stacking and fixing. As can be seen from the description of the manufacturing process, the guide pin <NUM> is used for positioning the second heat transfer plate <NUM>, and the guide pin <NUM> is used for positioning the first heat transfer plate <NUM>.

Further, the tip ends of the guide pins <NUM> and <NUM> are fitted into the concave portions on the back surfaces of the protrusions <NUM>, and the heat transfer plates <NUM> and <NUM> on the upper layer are pressed against the heat transfer plates <NUM> and <NUM> below. Therefore, frictional resistance is generated between the flat portion of the base <NUM> in which the protrusion <NUM> is fitted and the region of the headers 6a, 6b, 6c, and 6d that abuts on the flat portion of the base <NUM>. As a result, reliability of ultrasonic welding is improved, and a yield is improved.

According to the heat exchange element <NUM> described above, the protrusion <NUM>, the base <NUM>, the cone cover <NUM>, and the cone <NUM> formed on the heat transfer plates <NUM> and <NUM> are less likely to cause positional deviation in a stacked state. Therefore, even by ultrasonic welding that applies vibration to the heat transfer plates <NUM> and <NUM>, positional deviation is less likely to occur in the heat transfer plates <NUM> and <NUM>. In addition, since the protrusion <NUM> is fitted into the recess 14a of the base <NUM> and the cone <NUM> is fitted into the cone cover <NUM> only by stacking the heat transfer plates <NUM> and <NUM>, positioning can be performed accurately and easily. In addition, if the protrusion <NUM> is tightly fitted into the recess 14a of the base <NUM> and the cone <NUM> is tightly fitted into the cone cover <NUM>, it is possible to further reduce occurrence of positional deviation. In addition, the heat transfer plates <NUM> and <NUM> contract toward a center thereof after molding. Since the recess 14a has an elongated hole shape whose longitudinal direction is a direction toward a center of the heat transfer plates <NUM> and <NUM> in plan view, the protrusion <NUM> is easily fitted into the recess 14a even when the position of the base <NUM> is deviated due to contraction toward the center of the heat transfer plates <NUM> and <NUM>. In addition, by the protrusions <NUM> abutting on the recesses 14a, the heat transfer plates <NUM> and <NUM> are prevented from being deviated from each other in a direction different from the direction toward the center of the heat transfer plates <NUM> and <NUM>, so that positioning accuracy is also improved.

Further, the protrusion <NUM> and the base <NUM> are at positions close to the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM> even in the regions of the headers 6a, 6b, 6c, and 6d, and the cone cover <NUM> and the cone <NUM> are also at the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Therefore, even when a force for deviating the heat transfer plates <NUM> and <NUM> acts by ultrasonic welding, a bending stress generated in the heat transfer plates <NUM> and <NUM> remains in a short distance range, so that it is possible to make the heat transfer plates less likely to be bent.

In addition, since the plurality of protrusions <NUM>, the plurality of bases <NUM>, the plurality of cone covers <NUM>, and the plurality of cones <NUM> are formed for each of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, positional deviation is further less likely to occur.

Further, since the protrusion <NUM> has a tapered shape, the cone cover <NUM> has a conical shape, and the cone <NUM> has a conical shape, it is easy to perform centering when the heat transfer plates <NUM> and <NUM> are positioned with each other or the heat transfer plate and the manufacturing device are positioned with each other, and the heat transfer plates <NUM> and <NUM> can be easily positioned with each other.

In addition, by performing ultrasonic welding in a state where accurate positioning is made, a range to be welded is less likely to reach other ranges, or a portion having a welding defect is less likely to occur. Accordingly, clogging due to excessive welding and leakage of air from the heat exchange element <NUM> can be prevented.

In addition, since the base <NUM> is provided such that the longer diagonal line among the two diagonal lines of the rhombus is along the air flow direction, and the top portion of the base <NUM> abuts on the adjacent heat transfer plate <NUM> or <NUM>, the base <NUM> is less likely to obstruct an air flow. In addition, by providing a gap between the base <NUM> and the belt-shaped flat portions <NUM>, <NUM>, <NUM>, and <NUM>, it is possible to reduce disturbance of a wind flow around the base <NUM> and the sides 1d, 1f, 2c, and 2e and to suppress occurrence of a pressure loss, as compared with a case where no gap is provided. Further, by disposing the bases <NUM> linearly in the air flow direction, it is possible to similarly reduce disturbance of the flow and suppress occurrence of a pressure loss. In addition, by disposing the base <NUM> as close as possible to the sides 1d, 1f, 2c, and 2e with the gap interposed therebetween, a distance between the welding point and the base <NUM> becomes as short as possible, and the positioning can be more effectively performed at the time of welding.

Further, since the base <NUM> is provided on the headers 6a, 6b, 6c, and 6d, a width of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> can be narrowed as compared with a case where the base <NUM> is provided on the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. If the heat transfer plates <NUM> and <NUM> have equal sizes, the headers 6a, 6b, 6c, and 6d can be widened as the widths of the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are narrower. Although the base <NUM> is to be provided in the flow path, by widening the headers 6a, 6b, 6c, and 6d, a pressure loss of the heat exchange element <NUM> can be reduced as compared with a case where the base <NUM> is provided in the belt-shaped flat portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

The configuration described in the above embodiment is an example of the contents of the present disclosure. The configuration of the embodiment can be combined with another known technique. A part of the configuration of the embodiment can be omitted or changed without departing from the gist of the present disclosure.

Claim 1:
A heat exchange element (<NUM>) formed by stacking a plurality of heat transfer plates (<NUM>, <NUM>), wherein
each of the heat transfer plates (<NUM>, <NUM>) includes:
a heat exchanger (<NUM>) adapted to allow air passing through one side in a stacking direction of a plurality of the heat transfer plates (<NUM>, <NUM>) and air passing through another side in the stacking direction to pass through in directions facing each other to cause heat exchange;
a header (6a, 6b, 6c, 6d) provided on one side and another side with the heat exchanger (<NUM>) interposed therebetween when viewed along the stacking direction; and
a joining edge (<NUM>, <NUM>, <NUM>, <NUM>) provided along a side of the heat exchanger (<NUM>) that is not in contact with the header (6a, 6b, 6c, 6d), wherein
the joining edge (<NUM>, <NUM>, <NUM>, <NUM>) of a plurality of the stacked heat transfer plates (<NUM>, <NUM>) are in contact with each other and joined by ultrasonic welding, and
the joining edge (<NUM>, <NUM>, <NUM>, <NUM>) is formed with a first convex portion (<NUM>) that protrudes along the stacking direction and a concave portion (<NUM>) into which the first convex portion (<NUM>) of an adjacent heat transfer plate (<NUM>, <NUM>) among the heat transfer plates (<NUM>, <NUM>) is fitted, characterized in that
the header (6a, 6b, 6c, 6d) is formed with a base (<NUM>) protruding along the stacking direction and having a recess (14a) formed at a top portion thereof, and a second convex portion to fit into the recess (14a) of an adjacent heat transfer plate (<NUM>, <NUM>) among the heat transfer plates (<NUM>, <NUM>).