GB2417315A - Heat exchange element with flame retardant and moisture permeable portions - Google Patents

Heat exchange element with flame retardant and moisture permeable portions Download PDF

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Publication number
GB2417315A
GB2417315A GB0523037A GB0523037A GB2417315A GB 2417315 A GB2417315 A GB 2417315A GB 0523037 A GB0523037 A GB 0523037A GB 0523037 A GB0523037 A GB 0523037A GB 2417315 A GB2417315 A GB 2417315A
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United Kingdom
Prior art keywords
members
moisture
base material
flame retardant
heat exchanging
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0523037A
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GB0523037D0 (en
GB2417315B (en
Inventor
Masaru Takada
Hidemoto Arai
Youichi Sugiyama
Hisao Yokoya
Kenzo Takahashi
Junji Harada
Masayuki Tsubaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Mitsubishi Paper Mills Ltd
Original Assignee
Mitsubishi Electric Corp
Mitsubishi Paper Mills Ltd
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Filing date
Publication date
Priority claimed from JP2003354635A external-priority patent/JP4206894B2/en
Application filed by Mitsubishi Electric Corp, Mitsubishi Paper Mills Ltd filed Critical Mitsubishi Electric Corp
Publication of GB0523037D0 publication Critical patent/GB0523037D0/en
Publication of GB2417315A publication Critical patent/GB2417315A/en
Application granted granted Critical
Publication of GB2417315B publication Critical patent/GB2417315B/en
Anticipated expiration legal-status Critical
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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/66—Salts, e.g. alums
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/16—Sizing or water-repelling agents
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
    • D21H21/34—Ignifugeants
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/30—Multi-ply
    • D21H27/40—Multi-ply at least one of the sheets being non-planar, e.g. crêped
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J1/00—Fibreboard
    • D21J1/08—Impregnated or coated fibreboard
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
    • F24F13/30—Arrangement or mounting of heat-exchangers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/14—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification
    • F24F3/147—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by humidification; by dehumidification with both heat and humidity transfer between supplied and exhausted air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0015—Heat and mass exchangers, e.g. with permeable walls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D9/0062—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by spaced plates with inserted elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D9/02—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the heat-exchange media travelling at an angle to one another
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F2203/00—Devices or apparatus used for air treatment
    • F24F2203/10—Rotary wheel
    • F24F2203/1032—Desiccant wheel
    • F24F2203/1036—Details

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Inorganic Chemistry (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

A heat exchange element comprises flat partition members 2 having a base material 2a impregnated with a moisture absorbent 2b and are alternately laminated with corrugated spacing members 3 impregnated with a flame retardant. The partition members 2 have first portions provided with a flame retardant but not a moisture absorbent at junction areas that are in contact with spacing members 3 and second portions provided with a moisture absorbent but not a flame retardant at areas other than the junction areas, and the spacing members 3 being provided with a flame retardant but not a moisture absorbent. Partition members 2 may be bonded to the spacing members by a vinyl acetate adhesive. Base material 2a may be nonporous pulp fibres or a gas impermeable microporous base material having a polyvinyl alcohol filler applied to fill the pores. The moisture absorbent 2b may be an alkali metal salt such as lithium chloride and calcium chloride. The spacing members 3 may also be pulp fibres and the flame retardant may be a guanidine salt such as guanidine chloride and guanidine sulfamate. The heat exchange element 1 may be used in air conditioners and ventilators.

Description

HEAT EXCHANGING ELEMENT
The present invention relates to a heat exchanging element of laminated structure for use in a heat exchanging apparatus for conducting heat exchange between two fluids in the field of air conditioning. In particular, the invention relates to a heat exchanging element for exchanging both latent heat and thermal energy.
A heat exchanging element of laminated structure typically presently used in the field of air conditioning comprises basic component members each of which is formed by laminating a partition member of flat shape and a spacing member of corrugated section. Here, the basic component members are laminated and bonded so as to make the directions of corrugation in their spacing members have substantially right angles with each other. The spacing members of this heat exchanging element form flow paths. Airflows of different states (typically, airflows of different temperatures and humidities) are passed through the flow paths which adjoin in the direction of lamination so that latent heat and thermal energy are exchanged between the fluids across the partition members.
The partition members lie between the two airflows, existing as the medium for latent heat and thermal energy exchange. The heat conductivity and moisture permeability of the partition members thus have a large impact on the efficiency of the latent heat and thermal energy exchange of the heat exchanging element. The spacing members have the role of maintaining the partition members at certain spacings to secure the flow paths for the two airflows to pass through.
In a heat exchanging element intended for air conditioning, it is particularly necessary to reduce the transfer of such gases as carbon dioxide (CO2) between the two airflows. Both the partition members and the spacing members thus require a high gas barrier property aside from the aforementioned capabilities.
Besides, the heat exchanging element itself must have high flame retardancy in view of ensuring product safety.
Various properties are thus required of the partition members and spacing members of the heat exchanging element, and various types of partition members and spacing members have been used accordingly.
In one of conventional examples of the heat exchanging element for exercising the aforementioned capabilities, base paper is produced from slurry consisting chiefly of paper making fibers, mixed with a moisture absorbing/desorbing powder and a heat fusing substance. The base paper is impregnated with a flame retardant if necessary, and then provided with a moisture absorbing/desorbing coat on either or both sides to produce heat exchanger paper.
The resulting heat exchanger paper is corrugated before laminated crosswise alternately (for example, see Japanese Patent Laid-Open Publication No. Hei 10-212691, pp. 3-4 and Fig. 1).
Another example is a heat exchanger which is composed of flat liner sheets and corrugated sheets. The liner sheets are made of flame resisting paper formed by adding a flame retardant and a moisture absorbent to paper that consists chiefly of pulp. The corrugated sheets are made of a polypropylene film having no moisture adsorbability. The corrugated sheets are joined with the liner sheets interposed therebetween with their directions of corrugation orthogonal to each other alternately (for example, see Japanese Patent Laid-Open Publication No. 2001-241867, p. 2 and Fig. 1).
Still another example is a heat exchanger in which a plurality of flat partition plates are laminated with the intervention of corrugated spacer plates. Here, the corrugated spacer plates are made of base paper that is produced from a mixture of a ceramic fiber base material and a plant fiber base material, followed by impregnation of a flame retardant.
The flat partition plates are also made of the same base paper impregnated with a flame retardant and a moisture absorbent (for example, see Japanese Patent Laid-Open Publication No. Sho 54-44255, pp. 1-2 and the drawings).
These conventional heat exchanging elements are characterized in that any of the partition members, i.e., the heat exchanger paper, the liner sheets, and the partition plates contain a flame retardant and a moisture absorbent overlapping in lamination or in mixture.
Nevertheless, such conventional configurations with the overlapping flame retardant and moisture absorbent have the following problems.
1) Take the case of transferring latent heat, or equivalently, moisture between the two airflows flowing along the respective sides of each partition member. In the conventional configurations, not only a layer of moisture absorbent but also a layer of flame retardant lies in the direction of transfer of the moisture. Thus, even if the moisture is absorbed by the layer of moisture absorbent, the layer of flame retardant resists the moisture transfer so that the amount of the moisture transfer decreases in that part, with a drop in the moisture permeability of the partition member as a result.
2) Then, for the sake of still higher moisture permeability, it may be possible to increase the amount of the moisture absorbent. Nevertheless, the maximum total amount of chemicals capable of application or impregnation to a unit area of the base material of the partition member is limited. In the conventional configurations where the moisture absorbent and the flame retardant are both applied to the same portion of the partition member, an increase in the amount of the moisture absorbent thus decreases the amount of the flame retardant with a drop in flame retardancy. The same holds vice versa, adding up to another problem of a trade-off between the moisture adsorbability and the flame retardancy.
3) Furthermore, since the moisture absorbent and the flame retardant are used in the same portion, deliberate selections of the two chemicals are required so as not to react with each other easily because of their contact. This means another problem which is a narrow choice of the moisture absorbent and the flame retardant. The narrow choice should be avoided as far as possible since it causes higher product cost.
As described in Japanese Patent Laid-Open Publication No. Sho 54-44255, moisture adsorbability and flame retardancy may be provided simultaneously by impregnating the partition members with a flame retardant having moisture adsorbability.
This moisture adsorbability, however, is not as high as that of a moisture absorbent, and it is therefore difficult to achieve exchange efficiency higher than with a moisture absorbent alone. In addition, the same problem as the aforementioned problem 3) also occurs in that such a flame retardant has only a limited choice.
According to the present invention, there is provided a heat exchanging element comprising partition members and spacing members laminated alternately, said partition members being spaced by said spacing members to form flow paths between the partition members so as to allow separate airflows to pass through adjacent flow paths and to exchange heat between said separate airflows via said partition members, wherein said partition members have first portions provided with a flame retardant but not a moisture absorbent at their junction areas in contact with said spacing members, and have second portions provided with a moisture absorbent but not a flame retardant at areas other than said junction areas; and said spacing members are provided with a flame retardant but not a moisture absorbent.
Since the moisture permeable portions provided with a moisture absorbent and the flame resisting portions provided with a flame retardant of the partition members and spacing members do not overlap each other within the partition members and do not overlap each other within the spacing members, the effect of the moisture absorbent is not hampered by the overlap with the flame retardant, so that it is possible elicit the effect of moisture permeation. As a result, it is possible to improve the effect of moisture permeation, so that the heat exchanging element achieves both an improved efficiency of heat exchange and flame retardancy.
Furthermore, the present invention allows the amounts of use of the moisture absorbent for providing moisture permeability and the flame retardant for providing flame retardancy to be set freely without restriction on each other, and allows the two to be selected irrespective of reactivity with each other so that the heat exchanging element improves in the efficiency of heat exchange while achieving flame retardancy.
A heat exchanging element according to an embodiment of the present invention will be described in more detail with reference to the accompany drawings, in which: Fig. 1 is a perspective view showing a heat exchanging element 1 which is not an embodiment of the present invention but is useful for understanding; Fig. 2 is a perspective view showing a unit component member of the heat exchanging element of Fig. 1; Fig. 3 is a sectional view of the unit component member of Fig. 2, taken along a direction perpendicular to the path thereof; and Fig. 4 is a sectional view of a unit component member of the heat exchanging element according to an embodiment of the present invention, taken along a direction perpendicular to the path thereof.
Fig. 1 shows the heat exchanging element 1 which is not an embodiment of the present invention but is useful for understanding. The heat exchanging element 1 is composed of partition members 2 and spacing members 3 which are laminated alternately. The partition members 2 have a flat shape. The spacing members 3 have a corrugated section of serrate shape, sinusoidal shape, or the like. The spacing members 3 are formed so that their projections onto the planes of the partition members 2 coincide with the partition members 2. As shown in Fig. 2, a unit component member is fabricated by laminating a single partition member 2 and a single spacing member 3 so as to make contact at the convex portions of the corrugated shape, and fixing the same by such means as adhesive bonding. Such unit component members are laminated with the partition members 2 and the spacing members 3 in alternate layers so that the openings of the corrugated shapes of the spacing members 3 alternate by approximately 90 in direction (Fig. 1 shows an example where six unit component members are laminated into the heat exchanging element).
Consequently, as shown in Fig. 1, the heat exchanging element 1 has flow paths 4 and 5 for the two types of airflow (shown by the arrows) intersecting each other in alternate layers. Two types of airflows having different states can pass through the two types of flow paths 4 and 5 to exchange latent heat and thermal energy between the airflows by the medium of the partition members 2.
Fig. 3 is a sectional view of the unit component member of Fig. 2, taken perpendicularly to the direction of airflow through the flow path 4 or 5. For the sake of securing the moisture permeability, gas barrier property, and flame retardancy, the partition members 2 and the spacing members 3 of the heat exchanging element 1 are given the following configuration.
Each of the partition members 2 is composed of a base material 2a and a moisture absorbent 2b applied to the base material 2a. The base material 2a is made of a cellulose-based material, such as nonporous pulp fibers (paper produced from beaten pulp), or a gas-impermeable microporous base material.
The moisture absorbent 2b is an alkali metal salt such as lithium chloride and calcium chloride. The base material 2a is impregnated or coated with this moisture absorbent 2b. The spacing members 3 are also formed by impregnating pulp fibers with a guanidine-salt flame retardant such as guanidine chloride and guanidine sulfamate. A partition member 2 and a spacing member 3 are pasted to each other by an adhesive such as vinyl acetate adhesive, to form an unit component member as shown in Fig. 3.
The base material 2a of the partition member 2 itself is resistant to moisture transfer, and thus is desirably thinned as much as possible. The preferable thickness of the base material 2a is approximately 25 him to 150 Em or so, however, since a reduction in the thickness causes an abrupt drop in material strength with deterioration in workability. In view of the gas barrier property, the base material 2a is made of nonporous film material. Water vapor cannot pass through nonporous material as if through porous material. Thus, the moisture transfer presumably takes the form that moisture is absorbed into the surface of the partition member 2 and permeates the same before it passes through the partition member 2 by moisture diffusion. According to this principle, the base material 2a of the partition member 2 is preferably made of hydrophilic material which has excellent moisture diffusibity, containing hydrophilic groups such as a hydroxyl group.
The base material of the spacing member 3 is so-called flame-resistant paper, made of ordinary pulp to which a guanidine-salt flame retardant is given at the stage of paper production. This paper is generally equivalent to flame retardancy grade 2 (JIS A1322, method of testing building thin material for flame retardancy). Otherwise, paper impregnated or coated with a flame retardant on either or both sides may also be used. The single-side coating, however, may be somewhat less effective when heated from the side opposite to the coated one. In consideration of its role of forming and
-
maintainingthepaths, the spacing member 3 is preferably as thick as possible for the sake of higher strength. When a thin partition member 2 is bonded to a thick spacing member 3 to form the unit component member as shown in Fig. 2, however, there might occur the phenomenon that the component member itself curves because of a difference between the size variations of the two members 2 and 3 resulting from moisture absorption after fabrication, and because of a difference between the strengths of the same. Such component members could cause a serious deterioration in workability when they are subsequently laminated into the element form as shown in Fig. 1. The thickness must therefore be determined with consideration given to those factors. In the present embodiment, a thickness of approximately 100 Am is employed.
In the heat exchanging element 1 configured thus, the moisture absorbent and other chemicals including the flame retardant will not overlap each other on the partition members 2 which function as the medium for heat exchange. This provides the following two effects.
1) There is nothing but the base material 2a of the partition members 2 alone which resists the transfer of the moisture absorbed in the moisture absorbent. This elicits the effect of the moisture absorbent more than in conventional articles, with an improvement to the moisture permeability of the partition members 2 themselves.
2) The amount of use of the moisture absorbent can be determined freely independent of that of the flame retardant.
Additional effects include an increase in the maximum possible amount of use of the moisture absorbent. These are combined into an ultimate effect that the heat exchanging element 1 improves in the efficiency of latent-heat exchange. In addition, since the effect of the moisture absorbent can be elicited, it is possible to reduce the amount of use of the moisture absorbent while maintaining the same performance as heretofore. This means a cost reducing effect.
3) Furthermore, since the moisture absorbent and the flame retardant are not mixed with each other, it becomes possible to use chemicals that are not available heretofore due to reactivity therebetween. This leads to the effect of providing a wider choice of chemicals. Consequently, inexpensive effective chemicals can be selected from a wider range, and used with cost reduction.
To verify these effects, a test was conducted in which two samples were compared for the efficiency of latent-heat exchange and that of enthalpy exchange, with the same element size and the same conditions of circulating airflows. The two samples were the heat exchanging element 1 of the present configuration and a heat exchanging element of laminate type according to a conventional example. The conventional one had partition members made of a base material having flame retardancy, consisting of porous material and a flame retardant additive, coated with a moisture absorbent, as well as spacing members made of paper, a typical porous material. Table 1 shows the results.
[Table 1]
Type of heat Efficiency ratio of Efficiency ratio of exchanging element latent-heat exchange enthalpy exchange heat exchanging element of conventional1 1
example
heat exchange element of present1.2 1.18 embodiment As can be seen, the present invention provides the effect that the heat exchanging element 1 improves approximately 20% in the efficiency of latent-heat exchange and approximately 18% in the efficiency of enthalpy exchange at the same time. It is thus confirmed that the configuration of this heat exchanging element 1 provides the effect of improving the exchange efficiencies, though the ratios may vary depending on the conditions etc. The flame retardancy of the heat exchanging element 1 is provided by the flame retardant which is included in the spacing members 3. As can be seen from Fig. 2 and others, the spacing members 3 have an area greater than that of the partition members 2. A greater amount of flame retardant can thus be applied as compared to the case where the partition
-
members 2 aloneare coated with the flame retardant.
To clarify the degree of flame retardancy of the heat exchanging element 1, a flame test specified in UL-723, one of US standards; was conducted on three samples. The three samples were, namely, the heat exchanging element 1, a heat exchanging element given flame-retardant treatment to its partition members alone, and one given flame-retardant treatment to both partition members and spacing members thereof. Table 2 shows the results of the test.
[Table 2]
Type of heat exchanging element Flame Smoke spread developed Conventional example l (Flame-retardant treatment to partition members and spacing O O members) Conventional example 2 (Flame-retardant treatment to partition member alone) lO 55 heat exchanging element of present embodiment (Flameretardant treatment to lO 5 spacing members alone) As can be seen, the heat exchanging element 1 has flame retardancy higher than that of the sample given flame- retardant treatment to its partition members alone, or rather has flame retardancy close to that of the sample given flame retardant treatment to both the partition members and spacing members thereof. Applying flame- retardant treatment to the spacing members 3 alone can thus provide practically sufficient flame retardancy.
Consequently, the incorporation of the present lo configuration into a heat exchanging element of laminate type can improve the efficiency of latent-heat exchange by virtue of such factors as elicitation of the effect of the moisture absorbent and an increase in the maximum possible amount of use thereof, while ensuring practically sufficient flame retardancy at the same time.
Incidentally, the heat exchanging element 1 described above ensures the gas barrier property by using a nonporous material for the base material of the partition members 2. Nevertheless, porous film materials may also be used. In this case, a filler must be applied to fill the pores for the sake of ensuring the gas barrier property. The filler may be made of polyvinyl alcohol (PVA) or the like which has moisture permeability and the barrier property. This allows filling with minimum hindrance to the effect of the moisture absorbent. As a result, it is possible to provide almost the same effects as those of the heat exchanging element 1 described above.
When the partition members 2 are made of such a porous material, nonporous films of polymeric material having high moisture adsorbability comparable to that of a moisture absorbent, namely, members having a gas barrier property and moisture adsorbability may be bonded instead of the filler.
This also provides the same effects. In this case, in order to reduce the resistance against moisture transfer, nonwoven lo fabric or the like of high air permeability, having a minimum thickness and high porosity, should be selected as the base material. The reduced resistance can further increase the moisture adsorbability of the entire partition members 2.
Note that the partition members 2 are made of the base material having the gas barrier property as described above, whereas there is a wide range of choices from nonporous to porous base materials for the spacing members 3.
In the heat exchanging element 1 described above, the partition members 2 are configured as moisture permeable portions provided with moisture permeability, and the spacing member 3 as flame resisting portions provided with flame retardancy. Since the moisture permeable portions and the flame resisting portions can be separated from each other, the effect of moisture permeation and the flame retardancy are obtained from the partition members 2 and the spacing members 3, respectively, so that the effect of the moisture absorbent or other materials for providing the moisture permeability is not affected hampered by the flame retardant or other materials for providing the flame retardancy.
In the heat exchanging element l described above, the partition members 2 are made of a nonporous base material or gas-impermeable microporous base material, and the base material is provided with the moisture absorbent.
The spacingmembers 3 are made of a base material selected from among nonporous and porous ones, and the base material is provided with the flame retardant. The partition members 2 can thus provide moisture permeability and prevent the transfer of carbon dioxide and other gases between the two types of airflows by their nonporous base material or gasimpermeable microporous base material. In other words, the partition members 2 can ensure both the moisture permeability and the gas barrier property.
In the heat exchanging element 1 described above, the partition members 2 are made of a porous base material, and the base material is provided with the filler having a gas barrier property and the moisture absorbent or is provided with the members having a gas barrier property and moisture adsorbability. The spacing members 3 are made of a base material selected from among nonporous and porous ones, and the base material is provided with the flame retardant.
The partition members 2 can thus ensure the gas barrier property by means of the filler or the gas barrier members while ensuring moisture permeability by means of the porous base material. In particular, when the base material is provided with the members having a gas barrier property and moisture adsorbability, it is possible to ensure the gas barrier property with a significant improvement in moisture permeability.
Fig. 4 is a sectional view showing the heat exchanging element according to an embodiment of the present invention. This sectional view is of the unit component member in Fig. 2, taken along a direction perpendicular to the airflow path formed by the spacing member.
In this heat exchanging element 1,a flame retardant 2c (guanidine-salt flame retardant) is applied to specified areas of the base material 2a of the partition member 2, where the partition member 2 is in contact with the spacing member 3, and a moisture absorbent 2b to the other areas. The moisture absorbent 2b consists chiefly of an alkali metal salt such as lithium chloride and calcium chloride. The spacing member 3 is made of flame-retarded paper which is impregnated with a guanidine-salt flame retardant such as guanidine chloride and guanidine sulfamate. The partition member 2 is pasted to the same spacing member 3 as that of the first embodiment by an adhesive (such as vinyl acetate type) to form the configuration of Fig. 4.
In this heat exchanging element 1, as in the heat exchanging element 1 initially described with reference to Fig. 3, the moisture absorbent 2b does not overlap the flame retardant in the areas of the partition members 2 not in contact with the spacing members 3, where moisture transfer takes place actually. Consequently, it is possible to obtain the same effects including an improvement in the efficiency of latent heat exchange as in the case of the heat exchanging element 1 of the first embodiment. Besides, still higher flame retardancy is obtained since the amount and the area of application of the flame retardant are greater than in the foregoing case where the flame retardant is not applied to the base material 2a of the partition members 2.
In this configuration, some consideration must be given to such factors as the reactivity between the moisture absorbent 2b and the flame retardant 2c since the flame retardant 2c and the moisture absorbent 2b come into contact at the borders between their respective areas of application (2b and 2c in Fig. 4). Nevertheless, this configuration is far more suited to a heat exchanging element 1 that requires particularly high flame retardancy, than those of other
examples.
In the heat exchanging element 1 of the present embodiment, the junction areas of the partition members 2 with the spacing members 3 are configured as flame resisting portions provided with flame retardancy, and the other areas as moisture permeable portions provided with moisture adsorbability. The spacing members 3 are configured as flame resisting portions provided with flame retardancy. It is therefore possible to give flame retardancy to the junction areas which hardly contribute to moisture permeability, thereby enhancing flame retardancy without impairing moisture permeability.
A chief characteristic of the heat exchanging elements 1 according to the embodiment of the present invention, in terms of configuration, consists in that the moisture permeable portions provided with moisture adsorbability and the flame resisting portions provided with flame retardancy, formed by providing the partition members 2 and the spacing members 3 with a moisture absorbent and a flame retardant, respectively, are prevented from overlapping each other within each individual partition member 2 and spacing member 3. It is this configuration that prevents the moisture permeable portions provided with moisture adsorbability and the flame resisting portions provided with flame retardancy from interfering with each other to cause adverse effects on the moisture adsorbability (moisture permeability) and/or the flame retardancy. Thus, selections of the moisture absorbent (moisture adsorbability applying agent), the flame retardant (flame retardancy applying agent), and the like, and the method of providing these agents to the base materials of these members may be publicly known ones unless departing from the gist of the present invention.
As above, the heat exchanging element of the present invention can be used effectively for heat exchanging apparatuses that conduct heat recovery in exchanging heat between room air and outdoor air for ventilation and other purposes in the field of air conditioning including air conditioners and ventilators.

Claims (8)

  1. Claims 1. A heat exchanging element comprising partition members and
    spacing members laminated alternately, said partition members being spaced by said spacing members to form flow paths between the partition members so as to allow separate airflows to pass through adjacent flow paths and to exchange heat between said separate airflows via said partition members, wherein said partition members have first portions provided with a flame retardant but not a moisture absorbent at their junction areas in contact with said spacing members, and have second portions provided with a moisture absorbent but not a flame retardant at areas other than said junction areas; and said spacing members are provided with a flame retardant but not a moisture absorbent.
  2. 2. A heat exchanging element according to claim 1, wherein the partition members are flat and the spacing members are corrugated.
  3. 3. A heat exchanging element substantially as hereinbefore described with reference to the accompanying drawings.
  4. 4. A total heat exchanging element comprising partition members and spacing members laminated alternately, said partition members being spaced by said spacing members to form flow paths therebetween so as to allow two types of airflows to pass through adjoining flow paths, and to exchange heat between said two types of airflows via said partition members, wherein said partition members and said spacing members have moisture permeable portions and flame resisting portions provided with flame retardancy, said both portions not overlapping with each other within each partition or spacing member.
  5. 5. The total heat exchanging element according to claim 4, wherein said partition members have only said moisture permeable portions, and said spacing members have only said flame resisting portions provided with flame retardancy.
  6. 6. The total heat exchanging element according to claim 4 or 5 wherein: said partition members are made of nonporous base material or gas impermeable microporous first base material, and said first base material is provided with a moisture absorber; and said spacing members are made of a second base material selected from among nonporous materials and porous materials, and said second base material is provided with a flame retardant.
  7. 7. The total heat exchanging element according to claim 4, 5 and 6, wherein: said partition members are made of a porous first base material, and said first base material is provided with a filler having a gas barrier property and a moisture absorber or is provided with a member having a gas barrier property and moisture adsorbability; and said spacing members are made of a second base material selected from among nonporous materials and porous materials, and said second base material is provided with a flame retardant.
  8. 8. The total heat exchanging element according to claim 4, 5, 6, or 7 wherein: said partition members have said flame resisting portions provided with flame retardancy at their junction areas in contact with said spacing members, and have said moisture permeable portions provided with moisture permeability at areas other than said junction areas; and said spacing members have only said flame resisting portions provided with flame retardancy.
GB0523037A 2003-10-15 2004-09-21 Heat exchanging element Expired - Fee Related GB2417315B (en)

Applications Claiming Priority (2)

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JP2003354635A JP4206894B2 (en) 2003-10-15 2003-10-15 Total heat exchange element
GB0420984A GB2407151B (en) 2003-10-15 2004-09-21 Heat exchanging element

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GB2417315B GB2417315B (en) 2006-07-05

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EP2138792A1 (en) * 2007-04-17 2009-12-30 Mitsubishi Electric Corporation Process for manufacturing total heat exchanger element and total heat exchanger element
EP2146171A1 (en) * 2007-05-02 2010-01-20 Mitsubishi Electric Corporation Heat exchanger element and heat exchanger
WO2012107156A1 (en) 2011-02-09 2012-08-16 Klingenburg Gmbh Heat and/or moisture exchange element
WO2015104426A1 (en) * 2014-01-13 2015-07-16 Zeidler Bernd Method and device for the concurrent transfer of heat and moisture between at least two different gas streams
WO2016082902A1 (en) * 2014-11-24 2016-06-02 Klingenburg Gmbh Plate element for a plate heat exchanger
US10012450B2 (en) 2012-01-20 2018-07-03 Westwind Limited Heat exchanger element and method for the production
US10415900B2 (en) 2013-07-19 2019-09-17 Westwind Limited Heat / enthalpy exchanger element and method for the production

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US11486650B2 (en) * 2017-03-31 2022-11-01 Mitsubishi Electric Corporation Total heat exchange element, method of manufacturing total heat exchange element, and total heat exchanger

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JPS5444255A (en) * 1977-09-13 1979-04-07 Sanyo Electric Co Ltd Heat exchanger
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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2138792A1 (en) * 2007-04-17 2009-12-30 Mitsubishi Electric Corporation Process for manufacturing total heat exchanger element and total heat exchanger element
EP2138792A4 (en) * 2007-04-17 2013-07-24 Mitsubishi Electric Corp Process for manufacturing total heat exchanger element and total heat exchanger element
EP2146171A1 (en) * 2007-05-02 2010-01-20 Mitsubishi Electric Corporation Heat exchanger element and heat exchanger
EP2146171A4 (en) * 2007-05-02 2014-02-19 Mitsubishi Electric Corp Heat exchanger element and heat exchanger
US8726978B2 (en) 2007-05-02 2014-05-20 Mitsubishi Electric Corporation Heat exchanger element and heat exchanger
WO2012107156A1 (en) 2011-02-09 2012-08-16 Klingenburg Gmbh Heat and/or moisture exchange element
US10012450B2 (en) 2012-01-20 2018-07-03 Westwind Limited Heat exchanger element and method for the production
US10415900B2 (en) 2013-07-19 2019-09-17 Westwind Limited Heat / enthalpy exchanger element and method for the production
US20160305673A1 (en) * 2014-01-13 2016-10-20 Bernd Zeidler Method and device for the concurrent transfer of heat and moisture between at least two different gs streams
WO2015104426A1 (en) * 2014-01-13 2015-07-16 Zeidler Bernd Method and device for the concurrent transfer of heat and moisture between at least two different gas streams
US20180238567A1 (en) * 2014-01-13 2018-08-23 Bernd Zeidler Method of making and using a membrane for heat and moisture exchange betrween gas streams
RU2674961C2 (en) * 2014-01-13 2018-12-13 Бернд ЦАЙДЛЕР Method and device for concurrent transfer of heat and moisture between at least two different gas streams
WO2016082902A1 (en) * 2014-11-24 2016-06-02 Klingenburg Gmbh Plate element for a plate heat exchanger

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GB2417315B (en) 2006-07-05

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