Patent Publication Number: US-2023146349-A1

Title: Dehumidifying element, dehumidifying device, and a method of manufacturing dehumidifying element

Description:
TECHNICAL FIELD 
     The present disclosure relates a dehumidifying element, a dehumidifying device provided with the dehumidifying element, and a method of manufacturing the dehumidifying element. 
     BACKGROUND ART 
     In the past, dehumidifying elements that dehumidify air have been known. Such a dehumidifying element has a layered body in which plural sheets having a wavy shape and a planar shape are alternately stacked on each other. In addition, the layered body is fitted into a casing, and the outer shape of the layered body is thus fixed. Patent Literature 1 discloses a dehumidifying device provided with such a dehumidifying element as described above. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: Japanese Patent No. 6636053 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     In general, each of sheets that form a layered body is a fibrous sheet and supports an adsorbent that adsorbs and desorbs moisture in air. The layered body expands when the adsorbent adsorbs moisture, and contracts when the adsorbent desorbs moisture. The adsorbent does not easily expand in a direction parallel to surfaces of the sheets since its expansion is restricted by the fibers of the sheets and portions of the adsorbent interfere with each other. By contrast, the adsorbent easily expands in a stacking direction where the sheets are stacked together, since no object that interferes with the adsorbent is present in the stacking direction. That is, the layered body easily expands in the stacking direction. 
     Thus, when the layered body that has been fitted into the casing and fixed expands, a great load is applied to the layered body in the stacking direction because of the expansion of the sheets. Therefore, there is a possibility that the great load applied from the casing to the layered body in the stacking direction will break the layered body. In Patent Literature 1, it is described that the material and the thickness of a casing are adjusted in consideration of the expansion of a layered body. However, the casing of Patent Literature 1 does not intend to reduce the probability that the layered body will be broken. 
     The present disclosure is applied to solve such a problem as descried above, and relates to a dehumidifying element that is made in such a manner as to reduce the probability with which a layered body will be broken. 
     Solution to Problem 
     A dehumidifying element of an embodiment of the present disclosure includes: a layered body in which a plurality of sheets supporting an adsorbent that dehumidifies air are stacked on one another, with gaps provided between adjacent ones of the plurality of sheets, the gaps allowing air to pass therethrough; a casing that holds the layered body; and a cushioning member provided between the casing and the layered body in a stacking direction in which the plurality of sheets are stacked on one another, the cushioning member being configured to expand and contract. 
     Advantageous Effects of Invention 
     According to an embodiment of the present disclosure, the dehumidifying element includes the cushioning member provided between the casing and the layered body in the stacking direction. Thus, when the layered body expands, a force of the layered body that presses the casing in the stacking direction of the sheets is reduced. That is, when the layered body expands and the casing holds the layered body, the load applied to the layered body in the stacking direction of the sheets is reduced. Therefore, in the dehumidifying element, the probability with which the layered body will be broken is reduced. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    illustrates a configuration of a dehumidifying device  1  according to Embodiment 1. 
         FIG.  2    is a perspective view of a dehumidifying element  2  according to Embodiment 1. 
         FIG.  3    is a perspective view of a dehumidifying element  2 A according to a modification of Embodiment 1. 
         FIG.  4    is a perspective view of a desiccant unit  51  according to the modification of Embodiment 1. 
         FIG.  5    is a perspective view of a dehumidifying element  102  according to Embodiment 2. 
         FIG.  6    is a perspective view of a dehumidifying element  102 A according to a modification of Embodiment 2. 
         FIG.  7    is a perspective view of a desiccant unit  151  according to the modification of Embodiment 2. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiment 1 
       FIG.  1    illustrates the configuration of a dehumidifying device  1  according to Embodiment 1. The dehumidifying device  1  is provided, for example, at a duct, and dehumidifies air that passes through the duct. In the dehumidifying device  1 , a first air passage  3  and a second air passage  4  are provided. In the first air passage  3 , a first dehumidifying element  2   a  is provided, and in the second air passage  4 , a second dehumidifying element  2   b  is provided. The first dehumidifying element  2   a  and the second dehumidifying element  2   b  dehumidify air having a relatively high humidity and humidify air having a relatively low humidity. It should be noted that “dehumidifying element  2 ” in the following description is a generic term for the first dehumidifying element  2   a  and the second dehumidifying element  2   b . The dehumidifying element  2  may be applied to a device other than the dehumidifying device  1  of Embodiment 1. 
     The dehumidifying device  1  has a first inflow port  5 , a first outflow port  6 , a second inflow port  7 , and a second outflow port  8 . The first inflow port  5  communicates with an outside air duct  9  through which outdoor air flows from the outside of a room to the dehumidifying device  1 . The first outflow port  6  communicates with an air-supply duct  10  through which outdoor air flows from the dehumidifying device  1  to the inside of the room. The second inflow port  7  communicates with a return air duct  11  through which indoor air flows from the inside of the room to the dehumidifying device  1 . The second outflow port  8  communicates with an exhaust duct  12  through which indoor air flows from the dehumidifying device  1  to the outside of the room. 
     The dehumidifying device  1  further includes an air-supply fan  21  and an exhaust fan  22 . The exhaust fan  22  sends air from the second inflow port  7  toward the exhaust duct  12 . The air-supply fan  21  sends air from the first outflow port  6 , from the outside of the room, toward the inside the room. 
     The dehumidifying device  1  switches the state of each of the first air passage  3  and the second air passage  4  between a first state and a second state. In the first state, the first air passage  3  communicates with the first inflow port  5  and the first outflow port  6 , and the second air passage  4  communicates with the second inflow port  7  and the second outflow port  8 . In the second state, the first air passage  3  communicates with the second inflow port  7  and the second outflow port  8 , and the second air passage  4  communicates with the first inflow port  5  and the first outflow port  6 . 
     The flow of air in the first state will be described. In the first air passage  3 , a first air  31  from the outside of the room flows through the outside air duct  9 . When passing through the first dehumidifying element  2 , the first air  31  is dehumidified. The dehumidified first air  31  flows through the air-supply duct  10  and is supplied into the room. In the second air passage  4 , a second air  32  from the inside of the room flows through the return air duct  11 . When passing through the second dehumidifying element  2   b , the second air  32  is humidified. The humidified second air  32  flows through the exhaust duct  12  and is exhausted to the outside of the room. 
     The flow of air in the second state will be described. In the first air passage  3 , the second air  32  from the inside of the room flows through the return air duct  11 . When passing through the second dehumidifying element  2   b , the second air  32  is humidified. The humidified second air  32  flows through the exhaust duct  12  and is exhausted to the outside of the room. In the second air passage  4 , the first air  31  from the outside of the room flows through the outside air duct  9 . When passing through the first dehumidifying element  2   a , the first air  31  is dehumidified. The dehumidified first air  31  flows through the air-supply duct  10  and is supplied into the room. 
     While one of the first dehumidifying element  2   a  and the second dehumidifying element  2   b  dehumidifies the first air  31 , the other dehumidifying element humidifies the second air  32  and can restore its dehumidification capacity, since moisture is desorbed from the other dehumidifying element. In the dehumidifying device  1 , of the first dehumidifying element  2   a  and the second dehumidifying element  2   b , the dehumidifying element that re-has the dehumidification capacity is used to dehumidify the first air  31  that flows from the outside of the room, by switching of the state of each of the first air passage  3  and the second air passage  4  between the first and the second state. Thus, the dehumidifying device  1  can continuously supply dehumidified air into the room. 
     (Configuration of Dehumidifying Element  2 ) 
       FIG.  2    is a perspective view of the dehumidifying element  2  according to Embodiment 1. The dehumidifying element  2  includes a layered body  41 , a casing  42 , a cushioning member  43   a , and a cushioning member  43   b . It should be noted that “cushioning member  43 ” in the following description is a generic term for the cushioning member  43   a  and the cushioning member  43   b . The dehumidifying elements  2  are provided in the dehumidifying device  1  such that a stacking direction, which will be described later, coincides with an up-and-down direction of the dehumidifying device  1 . 
     In the layered body  41 , a plurality of sheets having a wavy shape and a plurality of sheets having a planar shape, that is, wavy sheets and planar sheets, are alternately stacked on one another. Hereinafter, a direction in which the sheets of the layered body  41  are stacked on one another will be referred to as the stacking direction. In addition, a direction orthogonal to the stacking direction will be referred to as an end portion direction. The end portion direction corresponds to a lateral direction of the dehumidifying element  2 . The sheets of the layered body  41  extend in the end portion direction. Also, a direction orthogonal to the stacking direction and to the end portion direction will be referred to as an air-flow direction. The air-flow direction corresponds to a front-back direction of the dehumidifying element  2 . Between the adjacent ones of the wavy sheets and the planar sheets, gaps are provided to allow air to flow in the air-flow direction. It should be noted that the sheets that form along with the planar sheets the layered body  41  are not limited to the wavy sheets. The sheets may be, for example, knurled by an embossing roller or other tools. In addition, the layered body  41  may include only the wavy sheets or only knurled sheets. Also, in this case, the sheets are stacked on one another, with gaps provided between any adjacent ones of the sheets. 
     In each of sheets that form the layered body  41 , an adsorbent that dehumidifies air is supported by a sheet base material. The sheet base material is made of, for example, paper. It should be noted that the sheet base material may be selected from materials such as a nonwoven fabric base material made of polypropylene, polyethylene, polystyrene, polyester, or rayon, a metallic fiber nonwoven fabric made of a highly thermally conductive metal, such as, aluminum or copper, and a resin fiber nonwoven fabric. In addition, the sheet base material has minute pores between fibers that form the sheet base material. Air sent to the dehumidifying element  2  passes through pores of the sheet base material, and the air is diffused throughout the sheet. When the air is quickly diffused into the pores of the sheet base material, the contact between the air and the adsorbent supported on surfaces of the fibers in the sheet is promoted, and the speed of adsorption is thus increased, whereby a satisfactory adsorption performance is achieved. It should be noted that hydrophilic fibers may be used for the sheet base material, or the sheet base material may be subjected to a hydrophilization treatment. In the case of using such a material, the sheet base material has higher wettability and can thus support more efficiently the adsorbent on the surfaces of the fibers. 
     The adsorbent is, for example, a material that adsorbs and desorbs moisture in the air, and is made of a high molecular compound such as a polyacrylic acid salt and an inorganic compound such as a silica gel. The adsorbent is applied on a surface of the sheet base material, or the inside of the sheet base material is impregnated with the adsorbent. The adsorbent can be contained in the sheet base material, for example, by the following way: fibers and the adsorbent are mixed with each other to form a sheet-shaped nonwoven fabric or the adsorbent is mixed into paper. In the case where an adsorbent of dispersion liquid or of solution is used, the adsorbent may be applied onto the sheet base material, or paper or nonwoven fabric may be impregnated with the adsorbent. In the case where a fibrous adsorbent is used, the adsorbent itself may be fibers that form paper or nonwoven fabric. The sequence of a step of causing the sheet to support the adsorbent and a step of processing the sheet to form it into a wavy shape are adjusted in consideration of, for example, the workability of the sheet or the workability for adding the adsorbent. 
     The layered body  41  expands when the adsorbent adsorbs moisture. The layered body  41  contracts when the adsorbent desorbs moisture. The adsorbent does not easily expand in the end portion direction since its expansion is restricted by the fibers of the sheets and portions of the adsorbent interfere with each other. By contrast, the adsorbent easily expands in the stacking direction, in which an object that interferes with the adsorbent is absent. That is, the layered body  41  easily expands in the stacking direction. 
     The casing  42  is a frame body having a substantially rectangular shape and is open in the front-back direction. It should be noted that the shape of the casing  42  is not limited to the rectangular shape. The casing  42  may have a polygonal shape, a circular shape, or an oval shape. In addition, the material of the casing  42  is selected from various materials such as plastic, metal, and wood, based on the temperature and humidity of air and the speed of wind. 
     Each of the cushioning members  43  is a member that expands and contracts, and is, for example, a sponge sheet, a rubber sheet, or a binder. The material, the shape, or dimensions of the cushioning member  43  are adjusted appropriately. The cushioning member  43  has low air permeability. In addition, the air permeability of the cushioning member  43  does not change even when the cushioning member  43  expands and contracts. Thus, in the dehumidifying element  2 , a decrease in the dehumidification performance is reduced because air passes through the cushioning member  43  which does not contribute to dehumidification. It should be noted that the cushioning member  43  may have hygroscopicity. 
     The casing  42  holds the layered body  41  and the cushioning members  43  in the up-and-down direction and in the lateral direction. Thus, the outer shape of the layered body  41  is fixed. Each of the cushioning members  43  is provided between the layered body  41  and the casing  42  in the up-and-down direction and is bonded to the layered body  41  and the casing  42 . More specifically, the cushioning member  43   a  is bonded to an upper surface of the layered body  41 , and the cushioning member  43   b  is bonded to a lower surface of the layered body  41 . An upper end portion of the cushioning member  43   a  is bonded to an inner surface of an upper portion of the casing  42 , and a lower end portion of the cushioning member  43   b  is bonded to an inner surface of a lower portion of the casing  42 . Thus, even when the layered body  41  expands and contracts repeatedly, gaps are not easily formed between the cushioning member  43   a  and the upper surface of the layered body  41  and between the cushioning member  43   a  and the inner surface of the upper portion of the casing  42 . Also, even when the layered body  41  expands and contracts repeatedly, gaps are not easily formed between the cushioning member  43   b  and the lower surface of the layered body  41  or between the cushioning member  43   b  and the inner surface of the lower portion of the casing  42 . It should be noted that only one of the cushioning member  43   a , which is provided on the upper surface of the layered body  41 , and the cushioning member  43   b , which is provided on the lower surface of the layered body  41 , may be provided as the cushioning member  43 . In addition, it is not indispensable that the cushioning members  43  are bonded to the layered body  41  and the casing  42  that are adjacent to the cushioning members  43  in the up-and-down direction. In the case where the cushioning members  43  are not bonded to the layered body  41  or the casing  42 , the cushioning member  43   a  also contracts and expands in accordance with the upward expansion and the contraction of the layered body  41 ; and the cushioning member  43   b  contracts and expands in accordance with the downward expansion and the contraction of the layered body  41 . It should be noted that the casing  42  may hold the layered body  41  and the cushioning members  43  in a direction oblique to the stacking direction or to the end portion direction. 
     In addition, the movement of the layered body  41  and that of each of the cushioning members  43  in the front-back direction are limited. In the air-flow direction, the dimension of the casing  42  is larger than or equal to that of the layered body  41  at time at which the layered body  41  most greatly expands. Thus, the layered body  41  does not interfere with the first air passage  3  or the second air passage  4 . 
     End portions of the cushioning member  43  in the lateral direction are not bonded to the casing  42 . Thus, the end portions of the cushioning member  43  in the lateral direction, that is, the end portions thereof that are adjacent to the casing  42 , can be moved along the casing  42  in the up-and-down direction when the layered body  41  expands and contracts. It should be noted that in another embodiment, the cushioning member  43  may be bonded to the casing  42  in the lateral direction. Also, end portions of the layered body  41  in the lateral direction are not bonded to the casing  42 . Thus, the layered body  41  can be moved along the casing  42  in the up-and-down direction when the layered body  41  expands and contracts. It should be noted that in another embodiment, the layered body  41  may be bonded to the casing  42  in the lateral direction. 
     (Method of Manufacturing Dehumidifying Element  2 ) 
     A method of manufacturing the dehumidifying element  2  will be described. First, a layered-body preparing step of preparing the layered body  41  having the wavy sheets and the planar sheets that are stacked on one another is carried out. Next, a first bonding step of bonding the cushioning member  43   a  to the upper surface of the layered body  41  is carried out. Subsequently, a second bonding step of bonding the cushioning member  43   b  to the lower surface of the layered body  41  is carried out. Then, a setting step of setting the layered body  41  and the cushioning members  43  in the casing  42  is carried out. At this time, the casing  42  and the cushioning members  43  are bonded to each other. In such a manner, the dehumidifying element  2  is manufactured. It should be noted that the sequence of the first bonding step and the second bonding step may be changed appropriately. 
     The layered-body preparing step will be described in detail. First, a planar sheet is squeezed using, for example, a corrugating machine or a rack and a pinion, thereby forming a wavy sheet. Next, a planar sheet is laid on the wavy sheet to make a pair of sheets having the shape of a single-face corrugated board. Such single-face corrugated board-shaped sheets are then stacked on one another to form the layered body  41 . 
     It should be noted that when each of the cushioning members  43  is not bonded to the layered body  41  or the casing  42 , subsequent to the layered-body preparing step, a layered body setting step of setting only the layered body  41  in the casing  42  is carried out. Next, a first cushioning-member setting step of setting the cushioning member  43   a  on the upper surface of the layered body  41  is carried out. Then, a second cushioning-member setting step of setting the cushioning member  43   b  on the lower surface of the layered body  41  is carried out. In such a manner, the dehumidifying element  2  is manufactured. It should be noted that the sequence of the steps of setting and bonding of the cushioning members  43  may be changed appropriately. 
     In Embodiment 1, the dehumidifying element  2  includes the cushioning members  43  each of which is provided between the casing  42  and the layered body  41  in the stacking direction. Thus, when the layered body  41  expands, the force of the layered body  41  that presses the casing  42  in the stacking direction of the sheets is cushioned. That is, when the casing  42  holds the expanding layered body  41 , the load applied to the layered body  41  in the stacking direction of the sheets is reduced. Consequently, in the dehumidifying element  2 , the probability with which the layered body  41  will be broken is reduced. 
     The cushioning member  43  contracts when the layered body  41  expands in the stacking direction. Thus, in the dehumidifying element  2 , a region occupied by the layered body  41  is increased. Therefore, in the dehumidifying element  2 , even when the layered body  41  expands, the space between any adjacent ones of the sheets of the layered body  41  is hardly narrowed. Thus, the dehumidifying element  2  reduces the pressure loss of air that passes through the dehumidifying element  2 . In addition, the cushioning member  43  expands when the layered body  41  contracts in the stacking direction, thereby maintaining the contact between the layered body  41  and the casing  42 . Thus, gaps are not easily formed between the layered body  41  and the cushioning member  43  or between the casing  42  and the cushioning member  43 . Thus, air that passes through the dehumidifying element  2  easily flows to the layered body  41 , and the dehumidification performance of the dehumidifying element  2  is thereby improved. 
     In addition, according to Embodiment 1, the layered body  41  and each of the cushioning members  43  which are adjacent to each other in the stacking direction are bonded to each other. Moreover, the casing  42  and the cushioning members  43  which are adjacent to each other in the stacking direction are bonded to each other at end portions of the cushioning members  43 . Thus, even when the layered body  41  contracts and expands repeatedly, gaps are hardly formed between the layered body  41  and the cushioning members  43  and between the casing  42  and the cushioning member  43 . Therefore, air that passes through the dehumidifying element  2  easily flows to the layered body  41 , and the dehumidification performance of the dehumidifying element  2  is thus improved. 
     Furthermore, according to Embodiment 1, the casing  42  and the end portions of the cushioning members  43  which are adjacent to each other in the end portion direction are in contact with each other such that the end portions of the cushioning members  43  are movable along the casing  42  in the stacking direction. Thus, when the layered body  41  expands in the stacking direction, each of the cushioning members  43  is pressed toward the casing  42  by the layered body  41 , and entire part of the cushioning member  43  in the end portion direction moves evenly. Therefore, when the casing  42  holds the expanding layered body  41 , a load thereof that holds the layered body  41  is also applied evenly to the entire part of the layered body  41  in the end portion direction. In such a manner, in the dehumidifying element  2 , the load applied to the layered body  41  is distributed, and the probability with which the layered body  41  will be broken is thus reduced. 
     In addition, according to Embodiment 1, the end portions of the layered body  41  and the casing  42  which are adjacent to each other in the end portion direction are in contact with each other such that the end portions of the layered body  41  are movable along the casing  42  in the stacking direction. Thus, even the portions of the layered body  41  that are in contact with the casing  42  are movable in the stacking direction to the same degree as a central portion of the layered body  41  in the end portion direction. Therefore, when the layered body  41  expands and the casing  42  holds the expanding layered body  41 , the load of holding the layered body  41  is applied evenly to part of the layered body  41  that is entire part thereof in the end portion direction. As described above, in the dehumidifying element  2 , the load applied to the layered body  41  is distributed and the probability with which the layered body  41  will be broken is thus reduced. 
     Modification of Embodiment 1 
       FIG.  3    is a perspective view of a dehumidifying element  2 A according to a modification of Embodiment 1. As illustrated in  FIG.  3   , the dehumidifying element  2 A includes a plurality of desiccant units  51  and the casing  42 , which holds the desiccant units  51 . The desiccant units  51  are arranged in the casing  42  such that two rows of desiccant units  51  are arranged in the up-down direction, and two desiccant units  51  of each of the two rows are arranged in the lateral direction. 
       FIG.  4    is a perspective view of each of the desiccant units  51  according to the modification of Embodiment 1. As illustrated in  FIG.  4   , the desiccant unit  51  includes the layered body  41  and the cushioning members  43  which are provided on both sides of the layered body  41  in the up-and-down direction. More specifically, the cushioning member  43   a  is bonded to the upper surface of the layered body  41 , and the cushioning member  43   b  is bonded to the lower surface of the layered body  41 . The casing  42  and the end portions of the cushioning members  43  which are adjacent to each other in the up-and-down direction are bonded to each other. The casing  42  maintains the outer shape of the entirety of the four desiccant units  51  in the up-and-down direction and the lateral direction. 
     In the desiccant units  51 , of the cushioning members  43 , cushioning members  43  adjacent to each other in the up-and-down direction are bonded to each other. Thus, no gaps are provided between the cushioning members  43  adjacent to each other in the up-and-down direction. Therefore, air that passes through the dehumidifying element  2 A easily flows to each of the layered bodies  41 , and the dehumidification performance of the dehumidifying element  2 A is thus improved. 
     On the other hand, in the desiccant units  51 , of the cushioning members  43 , cushioning members  43  adjacent to each other in the lateral direction are not bonded to each other. Thus, in the desiccant units  51 , when the layered bodies  41  expand and contract, the cushioning members  43  adjacent to each other in the lateral direction move in the up-and-down direction. In addition, in the desiccant units  51 , of the layered bodies  41 , layered bodies  41  adjacent to each other in the lateral direction are not bonded to each other. Thus, in the desiccant units  51 , the layered bodies  41  adjacent to each other in the lateral direction move in the up-and-down direction, when the layered bodies  41  expand and contract. As described above, the layered body  41  of each of the desiccant units  51  moves independently of the other desiccant units  51 , and is not compressed or elongated by the other desiccant units  51 . Thus, the dehumidifying element  2 A reduces the probability with which the layered body  41  will be broken by a cause other than moisture adsorption and desorption of the layered bodies  41 . 
     It should be noted that in the desiccant units  51 , of the cushioning members  43 , one or both of cushioning members  43  adjacent to each other in the up-and-down direction may be omitted, and in this case also, cushioning members  43  adjacent to the casing  42  in the up-and-down direction expand and contract. Thus, also, when the layered body  41  of any of the desiccant units  51  expands, and presses the casing  42  in the up-and-down direction of the sheets, the force of pressing the casing  42  is lessened. That is, when the layered body  41  expands and the casing  42  holds the layered body  41 , a load applied to the layered body  41  in the up-and-down direction of the sheets is reduced. Therefore, in the dehumidifying element  2 , the probability with which the layered body  41  will be broken is reduced. 
     In addition, regarding the dehumidifying element  2 A, in each of the desiccant units  51 , the expansion and the contraction of the layered body  41  can be handled; that is, it can be handled in units of one desiccant unit  51 . Thus, in the dehumidifying element  2 A, the probability with which the entirety of the layered bodies  41  will be broken is further reduced. It should be noted that the desiccant units  51  may be arranged in only one of the up-and-down direction and the lateral direction. In addition, in each of the up-and-down direction and the lateral direction, three or more desiccant units  51  may be arranged. 
     Embodiment 2 
       FIG.  5    is a perspective view of a dehumidifying element  102  according to Embodiment 2. In Embodiment 2, the dehumidifying element  102  includes holding members  144 . In this regard, Embodiment 2 is different from Embodiment 1. Regarding Embodiment 2, components that are the same as those in Embodiment 1 will be denoted by the same reference signs, and their descriptions will thus be omitted. Embodiment 2 will be described by referring mainly to the differences between Embodiments 1 and 2. 
     As illustrated in  FIG.  5   , the dehumidifying element  102  includes a holding member  144   a  and a holding member  144   b . It should be noted that “holding member  144 ” in the following description is a generic word for the holding member  144   a  and the holding member  144   b . The dehumidifying element  102  is provided in the dehumidifying device  1  such that the stacking direction in the layered body  41  coincides with the up-and-down direction of the dehumidifying device  1 . In addition, regarding the dehumidifying element  102 , the positions of the cushioning members  43  and those of the holding members  144  are adjusted such that the cushioning members  43  and the holding members  144  are not in contact with and do not interfere with the first air passage  3  or the second air passage  4 . 
     Each of the holding members  144  has stretchability. The holding member  144   a  is provided between the layered body  41  and the casing  42  in the lateral direction and is bonded to the casing  42 . More specifically, the holding member  144   a  is provided on a left side portion of the layered body  41 , and a left end portion of the holding member  144   a  is bonded to an inner surface of a left side portion of the casing  42 . The holding member  144   b  is provided on a right side portion of the layered body  41 , and a right end portion of the holding member  144   b  is bonded to an inner surface of a right side portion of the casing  42 . It should be noted that each of the holding members  144  may be bonded to part of the layered body  41  that is adjacent to the holding member  144  in the lateral direction. In addition, it is not indispensable that an end portion of the holding member  144  is bonded to the part of the casing  42  that is adjacent to the holding member  144  in the lateral direction. 
     As describe above, the layered body  41  easily expands in the up-and-down direction. However, since the layered body  41  expands and contracts repeatedly, in the layered body  41 , a load applied in the lateral direction is also accumulated. Because of the stretchability of the holding member  144 , when the layered body  41  presses the casing  42  in the lateral direction, the holding member  144  lessens the pressing force acing on the casing  42 . The holding member  144   a  contracts and expands in accordance with the leftward expansion and the contraction of the layered body  41 . The holding member  144   b  contract and expands in accordance with the rightward expansion and the contraction of the layered body  41 . It should be noted that regarding the holding member  144 , only one of the holding member  144   a , which is provided on the left side portion of the layered body  41 , and the holding member  144   b , which is provided on the right side portion of the layered body  41 , may be provided. 
     In the layered body  41 , the load applied in the end portion direction is smaller than the load applied in the stacking direction. Thus, the material, the shape, or the dimensions of the holding member  144  are adjusted such that the holding member  144  has lower stretchability than that of the cushioning member  43 . For example, when being made of a material having a higher rate of expansion and contraction than that of the cushioning member  43 , the holding member  144  is formed to have such a shape or dimensions as to have a lower rate of expansion and contraction, whereby the stretchability of the holding member  144  is adjusted to be lower than that of the cushioning member  43 . 
     The holding member  144  is not bonded to the layered body  41 . In addition, a surface of the holding member  144  that is in contact with the layered body  41  is smoothed to prevent the adsorbent of the layered body  41  and fibers of the sheets from getting in the surface of the holding member  144 . Thus, the layered body  41  slides along the holding member  144  in the stacking direction in accordance with the expansion and the contraction of the layered body  41 . It should be noted that the material of the surface of the holding member  144  that is in contact with the layered body  41  may be changed to a material having high slidableness. In addition, it is not indispensable that the surface of the holding member  144  that is in contact with the layered body  41  is smoothed. However, the layered body  41  and the holding member  144  may be bonded to each other. 
     The holding member  144  has a low air permeability. In addition, the air permeability of the holding member  144  does not change even when the holding member  144  expands and contracts. This reduces a decrease in the dehumidification performance of the dehumidifying element  2 , because air passages through the holding member  144 , which does not contribute to dehumidification. It should be noted that the holding member  144  may have hygroscopicity. 
     Method of Manufacturing Dehumidifying Element  102   
     Next, a method of manufacturing the dehumidifying element  102  will be described. First, a layered-body preparing step of preparing the layered body  41  having the wavy sheets and the planar sheets that are stacked on one another is carried out. Next, a first bonding step of bonding the cushioning member  43   a  to the upper surface of the layered body  41  is carried out. Subsequently, a second bonding step of bonding the cushioning member  43   b  to the lower surface of the layered body  41  is carried out. Then, in a state in which the holding members  144  are provided at the left side portions of the layered body  41  and the cushioning members  43  and at the right side portions of the layered body  41  and the cushioning members  43 , a setting and bonding step of setting the layered body  41 , the cushioning members  43 , and the holding members  144  in the casing  42  is carried out. At this time, the casing  42  and the cushioning members  43  are bonded to each other. In such a manner, the dehumidifying element  102  is manufactured. It should be noted that the sequence of the first bonding step and the second bonding step may be changed appropriately. 
     It should be noted that when the cushioning members  43  are not bonded to the layered body  41  or to the casing  42 , subsequent to the layered-body preparing step, a layered body setting step of setting only the layered body  41  in the casing  42  is carried out. Next, a first cushioning-member setting step of setting one of the cushioning members  43  on the upper surface of the layered body  41  is carried out. Subsequently, a second cushioning-member setting step of setting the other cushioning member  43  on the lower surface of the layered body  41  is carried out. Then, a first holding-member setting step of setting the holding member  144   a  on the left side portion of the layered body  41  is carried out. Finally, a second holding-member setting step of setting the holding member  144   b  on the right side portion of the layered body  41  is carried out. In such a manner, the dehumidifying element  102  is manufactured. It should be noted that the sequence of the first cushioning-member setting step and the second cushioning-member setting step may be changed appropriately. 
     In Embodiment 2, each of the holding members  144  is provided between the casing  42  and the layered body  41  in the stacking direction. Thus, when the layered body  41  expands and the casing  42  holds the expanding layered body  41 , the load applied to the layered body  41  in the end portion direction is reduced. Therefore, in the dehumidifying element  102 , the probability with which the layered body  41  will be broken is reduced. 
     According to Embodiment 2, the layered body  41  and each holding member  144  which are adjacent to each other in the end portion direction are in contact with each other such that the end portions of the layered body  41  are movable along the holding member  144  in the stacking direction. Thus, even the portion of the layered body  41  that is in contact with the holding member  144  is movable in the stacking direction to the same degree as the central portion of the layered body  41  in the end portion direction. Therefore, when the layered body  41  expands and the casing  42  holds the expanding layered body  41 , such a holding load is also applied evenly to the layered body  41  throughout the entire part of the layered body  41  in the end portion direction. In such a manner, in the dehumidifying element  2 , since the load applied to the layered body  41  is distributed, the probability with which the layered body  41  will be broken is reduced. 
     In addition, according to Embodiment 2, the layered body  41  slides along the holding member  144  in the stacking direction in accordance with the expansion and the contraction of the layered body  41 . Thus, deterioration of the layered body  41  that would be caused by friction is reduced. 
     It should be noted that if the dehumidifying element  102  is provided in the dehumidifying device  1 , for example, such that the stacking direction coincides with the lateral direction of the dehumidifying device  1 , the force of the layered body  41  that presses the holding members  144  downward is enhanced under the influence of gravity. At this time, the portions of the layered body  41  that are in contact with the holding members  144  cannot be easily moved in the stacking direction. In Embodiment 2, the dehumidifying element  102  is provided in the dehumidifying device  1  such that the stacking direction coincides with the up-and-down direction of the dehumidifying device  1 . Thus, the portions of the layered body  41  that are in contact with the holding members  144  can be easily moved in the stacking direction to the same degree as the central portion of the layered body  41  in the end portion direction. 
     Modification of Embodiment 2 
       FIG.  6    is a perspective view of a dehumidifying element  102 A according to a modification of Embodiment 2. As illustrated in  FIG.  6   , the dehumidifying element  102 A includes a plurality of desiccant units  151  and the casing  42 , which holds the desiccant units  151 . The plurality of desiccant units  151  are arranged in the casing  42  such two rows of desiccant units  151  are arranged in the stacking direction, and two desiccant units  151  of each of the two rows are arranged in the end portion direction. The casing  42  maintains the outer shape of the entirety of the four desiccant units  151  in the up-and-down direction and the lateral direction. 
       FIG.  7    is a perspective view of each of the desiccant units  151  according to the modification of Embodiment 2. As illustrated in  FIG.  7   , the desiccant unit  151  includes the layered body  41 , the cushioning members  43  which are provided on both sides of the layered body  41  in the up-and-down direction, and the holding members  144  which are provided on both sides of the layered body  41  in the lateral direction. In each of the desiccant units  51 , the layered body  41  and each of the cushioning members  43  are bonded to each other. The casing  42  and the end portion of each cushioning member  43  which are adjacent to each other in the up-and-down direction are bonded to each other. The casing  42  and the end portion of each holding member  144  which are adjacent to each other in the lateral direction are bonded to each other. 
     In the desiccant units  151 , of the cushioning members  43 , cushioning members  43  adjacent to each other in the up-and-down direction are bonded to each other; and of the holding members  144 , holding members  144  adjacent to one each other in the up-and-down direction are bonded to each other, and holding members  144  adjacent to each other in the lateral direction are bonded to each other. In such a manner, no gap is provided between any adjacent two of the desiccant units  151 . Therefore, air that passes through the dehumidifying element  102 A easily flows to the layered body  41 , and the dehumidification performance of the dehumidifying element  102 A is thus improved. 
     In the dehumidifying element  102 A, in each of the desiccant unit  151 , the expansion and the contraction of the layered body  41  can be handled; that is, it can be handled in units of one desiccant unit. Thus, in the dehumidifying element  102 A, the probability with which the layered body  41  will be broken is further reduced. It should be noted that the desiccant units  151  may be arranged in only one of the up-and-down direction and the lateral direction. In addition, in each of the up-and-down direction and the lateral direction, three or more desiccant units  151  may be arranged. 
     REFERENCE SIGNS LIST 
     1: dehumidifying device,  2 : dehumidifying element,  2 A: dehumidifying element,  2   a : first dehumidifying element,  2   b : second dehumidifying element,  3 : first air passage,  4 : second air passage,  5 : first inflow port,  6 : first outflow port,  7 : second inflow port,  8 : second outflow port,  9 : outside air duct,  10 : air-supply duct,  11 : return air duct,  12 : exhaust duct,  21 : air-supply fan,  22 : exhaust fan,  31 : first air,  32 : second air,  41 : layered body,  42 : casing,  43 : cushioning member,  51 : desiccant unit,  102 : dehumidifying element,  102 A: dehumidifying element,  144 : holding member,  151 : desiccant unit