EP1106729B1 - Cross flow heat exchanger for laundry drier with condenser - Google Patents

Description

The invention relates to cross-flow heat exchangers for Condensation dryer with the characteristics of Preamble of claim 1.

From US-A-2,462,421 a heat exchanger is known which hot and cold air flows through in cross flow. The heat exchanger plates have webs over which they are Be kept apart. The webs extend over the entire length of the hot air duct.

From DE-A-23 40 003 an evaporator is known in which Sheet metal plates are shaped crosswise. There is one plate with its one embossing on the embossing of the another plate.

DE-A-198 38 525 describes a heat exchanger for dehumidifying made known by air, in which the webs also across the entire width of the humid air duct extend. The crosswise to the flow direction Shafts have an angular, symmetrical profile.

From DE-A-198 38 525 are cross-flow heat exchangers for Condensation dryer known. Opposite this itself due to a low material requirement, despite less Foil thickness of the heat exchanger plates through a through the Bars or spacers achieved great rigidity and due to good heat dissipation on the cooling air side distinguished construction, the invention deals with a further development of such cross-flow heat exchangers that the dimensions of the plate pack of the known cross-flow heat exchanger corresponding Dimensioning of the plate pack an increase or despite its smaller dimensions, an adequate or can achieve the same cooling performance.

Such a cross-flow heat exchanger stands out according to the invention by the characterizing features of Claim 1 from.

In a heat exchanger according to claim 1, wherein the Humid air duct can pass through the heat exchanger plates the webs on one or both sides of the Heat exchanger plates can be provided, depending on whether this to be oriented in a horizontal or vertical position.

With a vertical installation position, with two-sided The bar arrangement does not collect any condensate in the bars, see above that the web wall parts of the pocket-like cooling fins Form cooling surfaces, which intensive heat dissipation to ensure.

In the case of a horizontal installation position, however, the webs become provide only on the top of the plate so that they stay free of condensate.

In the heat exchanger according to the invention thus effect Bars or spacers next to a corresponding one Enlargement of the area to be covered by the cooling air Channel surfaces at the same time an effective air swirl.

The efficiency of the heat exchanger according to the invention can improve significantly by the fact that Moist air duct is formed as a flat tube, whereby one whose pocket-like webs with a horizontal arrangement of Heat exchanger plates expedient only to the upper one Form pipe flat side. In this case, the lower plate side of a heat exchanger plate on the of the heat exchanger plate underneath upwards protruding webs, so that despite the absence of the Bottom of the plate protruding downwards between Heat exchanger plates cooling air channels available and thus the Prerequisites for intensive heat dissipation created are.

The length of the extending across the moist air duct Ridges can be roughly the width of a flat tube trained moist air duct correspond. Is preferred however, a web length that is only a fraction of the Corresponds to the width of the flat tube, the webs in Longitudinal direction of the flat tube expediently on gap are provided offset to each other.

In a further embodiment of this heat exchanger construction it can be advantageous to use the webs at least over one Area of the flat tube wall part to the flow direction of the Cooling air directed obliquely, if necessary still densified in some areas or over the entire area flat tube wall part to each other in a symmetrical Provide inclined arrangement.

Such measures, depending on given installation conditions in condensation dryers an optimal one for the cooling air in the heat exchanger Flow control and distribution or optimal Achieve exposure to the cooling surface, whereby by a slightly convex curvature of the longitudinal sides of the web transverse to Flow direction of the moist air the flow conditions in the cooling air ducts can be further improved.

A reduced dimensioning with the same cooling capacity the heat exchanger plates will be possible, if the upper one and lower duct wall part of the moist air duct transverse to Flow direction of the moist air are formed corrugated and preferably the wavy lines of both pipe wall parts run parallel to each other.

To manufacture the heat exchanger plates or the Forming foils are suitable for various materials, such as Plastic or aluminum, as well as various Manufacturing processes. Becomes plate production Plastic film used, this is e.g. thermally like that to reshape two for example from each other independent halves, each forming a plate part incur to bring each other in line and then on opposite long sides close together weld, glue or join using pressure.

It is equally possible that the two plate parts provide plastic films from one piece and by folding the plastic film the two plate parts to cover each other and then only along two overlapping longitudinal edge parts with each other by welding, gluing or pressure joining connect.

Finally, a preferred manufacturing method consist of heat exchanger plates in a blow mold molded from an extruded plastic tube.

Suitable for the manufacture of plastic plate parts especially acrylonitrile-butadiene-styrene copolymers (ABS) or Polypropylene, where desired to achieve Cooling capacities or the necessary Thermal conductivity and stability a film thickness between 0.15 mm and 0.50 mm, preferably 0.30 mm, as advantageous has proven.

In the case of using an aluminum foil for the production plate parts or heat exchanger plates a film thickness between 0.14 mm and 0.20 mm, preferably 0.15 mm, the ones to be produced therefrom Panel parts along two opposite one another Edge parts by mutual gluing, folding or Pressure joints are to be connected airtight.

Fig. 1:

eine Stirnansicht eines Wärmetauscherplattenpakets für einen Kreuzstrom-Wärmetauscher gemäß einem ersten Ausführungsbeispiel;

Fig. 2:

eine Teildraufsicht des Wärmetauscherplattenpaketes gemäß Fig. 1;

Fig. 3:

einen Querschnitt des oberen Plattenteils eines ersten Ausführungsbeispieles einer Wärmetauscherplatte für einen Kreuzstrom-Wärmetauscher gemäß einem ersten Ausführungsbeispiel;

Fig. 4:

einen Querschnitt des unteren Plattenteils eines ersten Ausführungsbeispiels einer Wärmetauscherplatte für einen Kreuzstrom-Wärmetauscher gemäß einem ersten Ausführungsbeispiel;

Fig. 5:

einen Querschnitt einer aus den Plattenteilen gemäß den Fig. 3 und 4 gebildeten Wärmetauscherplatte;

Fig. 6:

einen Teillängsschnitt entlang der Linie VI - VI durch die Wärmetauscherplatte gemäß Fig. 5;

Fig. 7:

einen Querschnitt durch eine Kunststofffolie zur Bildung eines zweiten Ausführungsbeispieles einer Wärmetauscherplatte für einen Kreuzstrom-Wärmetauscher gemäß einem ersten Ausführungsbeispiel;

Fig. 8 und 9:

jeweils eine Draufsicht auf weitere Ausführungsbeispiele von Wärmetauscherplatten; und

Fig. 10:

eine Darstellung ähnlich Fig. 5 zu Veranschaulichung des Querschnittes einer im Blasverfahren gefertigten Wärmetauscherplatte für einen Kreuzstrom-Wärmetauscher gemäß einem ersten Ausführungsbeispiel.

The drawing illustrates preferred exemplary embodiments of the invention, the heat exchanger plates of the heat exchanger plate packs being made from plastic film. Show it:

Fig. 1:

an end view of a heat exchanger plate package for a cross-flow heat exchanger according to a first embodiment;

Fig. 2:

a partial plan view of the heat exchanger plate package according to FIG. 1;

Fig. 3:

a cross section of the upper plate part of a first embodiment of a heat exchanger plate for a cross-flow heat exchanger according to a first embodiment;

Fig. 4:

a cross section of the lower plate part of a first embodiment of a heat exchanger plate for a cross-flow heat exchanger according to a first embodiment;

Fig. 5:

a cross section of a heat exchanger plate formed from the plate parts according to Figures 3 and 4.

Fig. 6:

a partial longitudinal section along the line VI - VI through the heat exchanger plate according to FIG. 5;

Fig. 7:

a cross section through a plastic film to form a second embodiment of a heat exchanger plate for a cross-flow heat exchanger according to a first embodiment;

8 and 9:

in each case a top view of further exemplary embodiments of heat exchanger plates; and

Fig. 10:

a representation similar to FIG. 5 to illustrate the cross section of a heat exchanger plate made in the blowing process for a cross-flow heat exchanger according to a first embodiment.

The plate package 10 shown in Fig. 1 for one Cross-flow heat exchanger for condensation tumble dryers is, for example, of eight individual, as a whole each designated 12, for example horizontally one above the other stacked heat exchanger plates formed.

These heat exchanger plates 12 each have, for example three mutually parallel moist air channels 14 on that define flat tubes. Each heat exchanger plate 12 consists of a lower plate part 16 (Fig. 4) and a upper plate part 18 (Fig. 3), which from a corresponding deformed film are formed.

In the present case it is e.g. around a slide made of thermoplastic. It might as well be one Foil made of suitable metal, for example aluminum, for Come into play.

Used as a plastic material for the production of the film preferably ABS, with a film in a thickness of preferably 0.30 mm is thermoformed to the two Manufacture plate parts 16, 18.

The two, one each shown in Fig. 5 Form heat exchanger plate 12 forming plate parts 16, 18 complementary moldings, so-called blisters, the brought into register with each other and preferably only along outer longitudinal edge parts 20, 22 by welding be connected in a vapor-tight manner. Along from neighboring Moist air channels 14 are their laterally limiting Channel wall parts 28 preferably by pressing together connected, thereby increasing the stability of the heat exchanger plates 12 is favored.

Alternatively, the two plate parts 16 and 18, 7 shows, also by a one-piece as a blister preformed plastic film be formed, the halves then covered by folding and therefore only along two overlapping ones To weld longitudinal edge parts 30 and 31, for example are.

The two duct wall parts 24 and 26 of the flat tubes Forming moist air channels 14 are transverse to Flow direction of the humid air is corrugated, wherein both wavy lines preferably parallel to each other run. This measure creates one accordingly Enlarged surface of the cooling capacity which increases the cooling capacity Channel wall parts 24 and 26.

3 and 5, protrude from the top Plate part 18 on the outside vertically directed cooling fins 32 from, which is transverse to the longitudinal direction of the respective Extend moist air duct 14. The length of this Web-like cooling fins 32 could be approximately the width of the correspond to respective moist air duct 14.

In the embodiment shown, however, these are how can be seen in particular from Fig. 2, across the width each wet air duct 14 preferably in three Individual slats 32 of the same height divided that each other are provided offset.

The cooling fins 32 are, as shown in FIG. 6, through Thermoforming pocket-like, open to the moist air duct 14, molded so that the slat longitudinal wall parts 34 and 36 are spaced from each other, whereby these are preferably still slightly curved outwards are trained to the flow behavior in the To optimally design cooling channels 42.

By deep drawing the cooling fins 32, these are also rounded end edges 38 and 40 (Fig. 2) provided what has a favorable effect when flowing through cooling air.

With appropriate dimensioning of the cross section corrugated heat exchanger plates 12 and more suitable Arrangement and dimensioning of the pocket-like Cooling fins 32 can thus achieve maximum dehumidification achieve the wet air in the wet air channels 14.

If a metal foil, such as aluminum foil, use finds, the web-like cooling fins 32, in Comparison to those from a plastic film shaped, have a reduced height to prevent tearing to avoid the metal foil.

The cooling air is in through the heat exchanger plate pack 10 in the cooling air channels 42 crossing the moist air channels 14 (FIG. 6) passed through. These inevitably arise in that the layered on top of each other Heat exchanger plates 12 with their lower plate part 16 each on the web-like cooling fins 32 of the upper one Plate part 18 of those below Rest heat exchanger plate 12 (Fig. 6).

The cooling air flows around the cooling fins 32 and brushes the undulating outer surface of the lower and upper plate part 16 and 18, the configuration the same is designed so that with a minimal height of the Heat exchanger plate package 10 an optimal Dehumidification performance, e.g. 0% residual moisture, is achieved (1: 1 exchanger).

Possible variants of the arrangement of web-like Cooling fins 32 for forming a cooling air channel are shown in 8 and 9.

For the purpose of distributing a from an outlet port 33 of a machine mounted fan flowing airflow can 8 for example by a Blower outlet connection 33, facing, compressed Arrangement of cooling fins 32 in the inflow area a Achieve increase in flow resistance, or the Cooling fins 33 can, as shown in Fig. 9, e.g. symmetrical to the transverse center of the cooling air duct 42 under one Angle be inclined, if necessary, with increasing lateral distance from the center of the channel increased.

With such an arrangement of Bars 32 or bar groups can be one on the cooling air side significant increase in cooling performance through the optimal Achieve exposure to the cooling surface. It can be so in the case of design-related, unfavorable installation conditions of the heat exchanger in the housing Condensation dryer by selecting the appropriate for air routing and for swirling the cooling air leading pitch angle and by the number of webs 32 to be inclined compared to parallel directed webs 32 up to 20% more cooling capacity to reach.

The heat exchanger plate pack 10 is, analogously to Construction of DE 198 38 525 A1 cited above, at its both ends in one made of plastic existing holding frame kept sealed, which is using an adhesive, preferably cast resin, can be accomplished.

As an alternative to this, the heat exchanger plate package 10 on both sides against a punched or punched Soft rubber sheets are pressed in the relevant Holding frame is inserted.

Another advantageous way of connecting Heat exchanger plate pack and holding frame can be in it exist, the heat exchanger plates with each end to weld a holding frame.

In contrast to the horizontal one shown in FIG. 1 Arrangement of heat exchanger plates 12, these can also in a vertical arrangement rotated by 90 ° be provided. In this case, both Duct wall parts 24, 26 of the moist air ducts 14 pocket-like, open webs 32 are formed. From the itself then vertically extending webs 32 can be attached to them draining condensate. The one from the double-sided web arrangement resulting enlargement of the Cooling surface of the moist air channels 14 enables another Reduction in the size of the heat exchanger plates 12.

Another embodiment of an inventive Fig. 10 illustrates heat exchanger plate in its Cross-sectional design essentially corresponds to that 3 to 5, but with the Difference that they are rather than by each other plastic films connected in a vapor-tight manner Plastic existing molded body 44 is formed from one piece is made by blowing.

For this purpose, an extrusion process is used Plastic hose with a wall thickness of, for example 0.40 mm wall thickness in a thermoplastic state in one Blow mold introduced, in both hose ends squeezed and radially into the cross-sectional shape shown blown. Then the closed ones Hose ends separated from the molded body 44.

This manufacturing method largely enables one scrap-free manufacturing process.

The wave profile can be transverse to the direction of flow Cooling air is also asymmetrical, i. i.e., the Rise phase in the flow direction is flatter and the Fall phase steeper. This allows the pressure drop reduce and flow separations on the sloping Avoid page largely.

Claims (15)

1. Countercurrent heat exchanger for condensation laundry dryers, having several flat heat exchanger plates (12) which are layered in parallel to each other at separation distances as a stack (10), where each plate contains at least one humid air channel (14) and is made out of a film consisting of a thermoplastic plastic or out of a heat-conducting metal foil as well as has several struts (32) that form cooling lamellas projecting out from them, which extend perpendicularly to the humid air channel (14) and, supported together on an adjacent heat exchanger plate (12), form cooling air channels (42), where the heat exchanger plates (12) are fixed on their facing ends that have the openings of the humid air channel (14) so that they are sealed off from each other in a mounting frame, wherein the struts (32) that form the cooling lamellas are shaped as pockets that open towards the humid air channel (14), characterized in that the length of the pocket-like struts (32) molded onto the one flat tube wall part (26) of the flat tube only amounts to a fraction of the width of the flat tube and that the struts (32) are arranged offset from each other by gaps in the longitudinal direction of the humid air channel (14), that the at least one humid air channel (14) is formed by a flat tube and that the pocket-like struts (32) are at least molded onto its one flat tube wall part (26) and that the upper and lower flat tube wall parts (24, 26) of the flat tube are constructed corrugated perpendicularly to the flow direction of the cooing air and that the wave curves of both tube wall parts (24, 26) run in parallel to each other and wherein the profile of the wave runs asymmetric perpendicular to the flow direction, which means that the rising phase in flow direction is shallower and the declining phase is steeper.
2. Countercurrent heat exchanger according to claim 1, characterized in that the struts (32) are bent in a slightly convex manner to the outside on their strut length sides (34, 36), perpendicular to the flow direction of the humid air.
3. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the struts (32) are oriented on the flat tube wall part at least over a surface area of it, at an angle to the current flow direction of the cooling air.
4. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the struts (32) are provided in a compacted arrangement, at least in certain areas, on the flat tube wall part on the current stream side of the heat exchanger plates (12) through the cooling air.
5. Countercurrent heat exchanger according to claim 3 or 4, characterized in that the struts (32) oriented at an angle over the entire flat tube wall part in the current stream direction of the cooling air, are ordered in a symmetrical arrangement to each other.
6. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the heat exchanger plates (12; 52) each made out of two plate edge parts arranged congruently and lying on top of each other, are connected in an air-tight manner with each other, and consist of plate parts (16, 18) that are formed from plastic films.
7. Countercurrent heat exchanger according to claim 8, characterized in that the plastic films that form the two plate parts (16, 18) are a single piece and are made to overlap each other by folding and are bonded together along the two longitudinal edge portions that cover each other by fusing, adhering, or pressure-attaching.
8. Countercurrent heat exchanger according to claim 7, characterized in that the two halves (16, 18) of the plastic film that each form one of the flat tube wall parts (24 or 26) are shaped along their foldable connection piece in a groove-like manner in such a way that for the halves of the plastic film of this connection piece, which are made to overlap, a longitudinal edge piece of the flat tube, which is U-shaped in cross-section, is formed.
9. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the heat exchanger plates (12; 52) are formed by a blow molded part made out of plastic.
10. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the plastic for the blow-molded part or the plastic film is made of acrylonitrile-butadiene-styrene copolymers (ABS) or polypropylene.
11. Countercurrent heat exchanger according to claim 10, characterized in that the heat exchanger plates (12) constructed as a blow-molded part or the plastic film for the construction of the heat exchanger plates (12) have a wall or film thickness of between 0,15 mm and 0,50 mm, preferably 0,30 mm.
12. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the metal film to create the plate parts (16, 18) is an aluminum film with a thickness of between 0,14 mm and 0,20 mm, preferably 0,15 mm.
13. Countercurrent heat exchanger according to claim 12, characterized in that the plate parts (16, 18) of the heat exchanger plates (12), consisting of aluminum film, and connected to each other in an air-tight manner along two edge parts lying opposite each other, are adhered, folded, or pressure-attached together.
14. Countercurrent heat exchanger according to one of the preceding claims, characterized in that the heat exchanger plates (12) are arranged horizontally or vertically.
15. Countercurrent heat exchanger according to one of the claims, characterized in that adjacent humid air channels (14) are pressure attached together with connecting connection struts (28).

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