DE202011000660U1 - Heat exchanger, in particular a condensation tumble dryer - Google Patents

Abstract

Heat exchanger (1, 27), in particular heat exchanger of a condensation tumble dryer, comprising a heat exchanger block (10) consisting of several, a cooling air surface forming, metal laminar layers (3, 25, 25a, 25b) for passing dry cooling air in a cooling air flow direction (KL) wherein between each of the lamellar layers (3, 25, 25a, 25b) at least one process air surface forming tube (2, 24) for passing moist process air in a process air flow direction (PL) is arranged, wherein front ends (16) of the tubes (2, 24) extend beyond the edge of the lamellar layers (3, 25, 25a, 25b) and protrude into and adhere to a respective holding frame (4), characterized in that on the respective top and bottom of the tubes (2, 24 ) in each case a lamellar layer (3, 25, 25 a, 25 b) is attached, wherein the ratio between the cooling air surface and the process air area is greater than or equal to 7, 0 is.

Description

The present invention relates to a heat exchanger, in particular a heat exchanger of a condensation dryer according to the preamble of claim 1 and a condensation dryer.

Generic heat exchangers for condensation dryer are known in numerous variants of the prior art. In today's glued or soldered heat exchangers, the heat exchanger block consists of four to seven flat tubes for guiding the process air and five to eight lamellae for the cooling air flowing perpendicular to the process air. These lamellar layers, usually of the offset type, are connected to the tubes by gluing or brazing. The outer lamellar layers are covered by flat side parts. The front pipe ends are glued tight and tight in a frame made mostly of plastic. This bonding is usually carried out on the side facing the lamellar layers of the frame, in which by means of metering a thick adhesive bead between the walls of adjacent tubes and a web of the frame is placed.

This allows a fast, but comparatively much adhesive-consuming production of such heat exchangers. The heat technically usable length of the lamellar layer is limited by the space required for metering the adhesive space, which reduces the performance of the heat exchanger.

In order to increase the heat technically usable length of the lamellar layer, it is known to glue the front end pipe ends on the side facing away from the lamellar layer of the frame. However, this bonding is very complex, since there is the danger that a part of the adhesive penetrates into the tube ends.

From the EP 0 305 702 A1 It is known to expand the front ends of the tubes and to press them into a circumferential plug-in groove in an edge of the tube sheet and, if necessary, to glue the tubes to the tubesheet.

Object of the present invention is therefore to provide a heat exchanger that provides in a given space and without changing the Luftanströmungsparameter increased compared to conventional heat exchangers performance and is less expensive to produce.

This object is achieved by a heat exchanger with the features of claim 1.

According to the invention, in each case a lamellar layer is fastened on the upper side and the underside of the tubes, which stacked together form the height of a lamella forming a cooling air surface. The surface of the lamellar layer is greater than or equal to 7.0 in relation to the process air area. With such an area ratio a significant increase in performance of the heat exchanger is possible with the same space of the heat exchanger.

Advantageous embodiments of the invention are the subject of the dependent claims.

To achieve this area ratio, the ratio between the height of the slats perpendicular to the cooling air surface and the cam pitch of the slats is greater than or equal to 2.4 according to a particular embodiment variant.

Such a large slat height makes it possible to reduce the number of slats and also the number of tubes of a heat exchanger block, which is associated with significantly lower production costs.

The lamellar layers are formed according to a further advantageous embodiment as rolled lamellar layers. Although this requires to achieve the predetermined conditions between cooling air surface and process air surface or between fin height and cam pitch a larger number of lamellae, but has the great advantage that the lamellae can be made faster by rolling. In addition, for rolls made by rolling much thinner materials can be used and thus the cost of materials can be reduced.

According to a further advantageous embodiment of the invention, the front ends of the tubes are flared and conically mounted on correspondingly shaped, provided with an adhesive and extending in the cooling air flow direction webs of the holding frame. Under a conical widening here is not only an expansion in the sense of a straight-line trapezoidal design to understand, but for example, a curved shape shape, for example, similar to a Parabelfußes, or even a stepped expansion. Due to the conical widening of the pipe ends, on the one hand the lamellar layer can be brought closer to the front ends of the pipes, since the space for introducing the adhesive metering pipes is no longer needed, so that thereby the usable cooling air surface and also the process air surface formed by the individual lamellae of the lamellar layers is enlargeable, which is associated with an increase in the performance of the heat exchanger. In addition, by the described type of Bonding a significant amount of adhesive can be saved.

According to a further embodiment of the invention, the lamellar layers extend to the conically widened areas of the tubes, which is accompanied by an increase in the process air area and thus an increase in performance with the same installation space of the heat exchanger.

According to a further embodiment of the invention, the webs of the holding frame on conically shaped walls, which open into respective filled with the adhesive grooves. In particular, in each case a parallel to the outer walls of the webs extending inner web are integrally formed in the webs of the support frame, wherein the filled with the adhesive grooves are bounded by a wall of the inner web and the conically shaped wall. As a result, the channels filled with adhesive are shaped such that with a minimal amount of adhesive, the pipe ends can be securely bonded to the support frame.

In the conically shaped walls of the webs preferably pocket-shaped bulges for uniform distribution of the adhesive between the walls of the webs and the inner surfaces of the front ends of the tubes are integrally formed. As a result, the best possible strength and tightness of the bonding of the pipe ends is made possible with the holding frame.

According to a further advantageous embodiment of the invention, the lamellar layers are glued to the top or bottom of the tubes, whereby also the production costs can be kept low. The tubes are preferably stacked loosely on top of each other in the region of the lamellar layers attached to them.

According to a further embodiment, the block of a heat exchanger from the cooling air surface forming tubes for passing dry cooling air in a cooling air flow direction, wherein on the respective top and bottom of the tubes in each case a lamellar layer is attached. As a result, lamellar layers of opposite the above-mentioned embodiments halved height on the tube sides are fixed, or glued in particular soldered by stacking these elements, the lamella height between the individual tubes back to a total lamella height as in the embodiments described above and thus the same performance increase is achievable.

Embodiments of the invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 a perspective view of an embodiment of a heat exchanger according to the invention,

2 a perspective view of a portion of a slat layer according to the invention,

3 two side sectional views for comparing a conventional heat exchanger to an embodiment of a heat exchanger according to the invention,

4 a perspective view of a heat block of a heat exchanger with conically flared pipe ends,

5 a perspective view of the pipe ends and fin layers before mounting the pipe ends to the support frame,

6 a detail view of the frame with the in 3 shown embodiment of the heat exchanger according to the invention glued tube ends,

7 a perspective view of a variant of a heat exchanger block of a heat exchanger according to the invention,

8th a perspective view of the heat exchanger of Figure in the assembled state,

9 a perspective view of a heat block of a heat exchanger with rolled blades and

10 a cross-sectional view of embodiments of two differently shaped slats.

In the following description of the figures, terms such as top, bottom, left, right, front, back, etc. refer exclusively to the exemplary representation and position of the heat exchanger and other parts selected in the respective figures. These terms are not intended to be limiting, that is to say, by different working positions or the mirror-symmetrical design or the like, these references may change.

1 shows a heat exchanger 1 with a plurality of here five, designed as individual tubes pipes 2 which are arranged parallel to each other and in a plurality of planes at a distance from each other. Also conceivable is an arrangement of a plurality of parallel juxtaposed rows of tubes 2 , Between or above and below the tube (s) 2 is in each case a lamellar layer 3 arranged. The topmost lamellar layer 3 and the lowest lamellar layer 3 be doing of a sheet side part 8th covered. The pipes 2 In this case, wet process air flows through in a first direction indicated by an arrow PL, while dry cooling air flows through the lamination layers in a second direction indicated by the arrow KL 3 flows.

Cooling air surface is understood to mean the heat-exchanging surface which is in direct contact with the flowing cooling air and consists of the sum of the tube outer surfaces which are not covered by adhesive or lamella cams and which are more or less parallel to the outer surface of the tubes 2 extending surfaces of the lamellae and in particular the surfaces of projecting from the tube surfaces lamella flanks. The outer surfaces of the narrow sides of the pipe lying in the inflow or outflow region of the cooling air likewise belong to the cooling air surface. Not the cooling air surface includes the proportions of the tube outer or lamellar surfaces, which are covered with adhesive or lie directly on or against each other, so that they can not be flown by cooling air. The cooling air surface does not include the surfaces of the side parts that are flown on 28 as well as through these directly covered outer lamellar surfaces.

The process air area is the sum of all acted upon by the process air inner surfaces of the tubes 2 whose outside is flowed by cooling air or provided with lamellae. The process air area does not belong in the frame 4 attached pipe ends 26 ,

The pipes 2 are to the lamellar layers 3 preferably aligned in the manner of a cross-flow heat exchanger, ie perpendicular to each other.

At the open ends of the pipes 2 are respective frames 4 . 5 tightly glued. These frames have respective seals 6 . 7 for sealing in a housing of a floor group of a dryer.

2 shows a section of a lamellar layer 3 , which is preferably formed as an "offset blade", with a height H and a cam pitch NT. This lamella cuts in the direction of air flow 9 through which the lamellar surfaces, which are parallel in the direction of flow, are offset by approximately a quarter of a cam pitch in order to break the flow boundary layer and thus improve the heat transfer. The ratio between the height H of the lamellar layer 3 and the cam pitch NT of the lamination layer 3 is preferably greater than or equal to 2.4. With a slat height selected in this way, the number of slats can be 3 and / or reduce the number of tubes of a heat exchanger at a constant power, which is associated with lower production costs. The lamellar layers 3 are in the direction of flow substantially rectangular and formed on the rectangular narrow sides of the respective tube 2 attached, in particular glued or soldered. An embodiment of the lamellar layers 3 in, for example, triangular or rounded shape is also conceivable.

The 3 shows in the upper part of the upper half of a conventional heat exchanger in cross section. It can be seen that the pipe ends 11 on the lamellar layers 3 facing sides by means of an adhesive 12 tight and firm with the frame 4 . 5 are connected. This adhesive is used during assembly of the heat exchanger 1 after attaching the frame to the pipe ends 11 by retracting dosing pipes into a free space 13 between the pipe ends and the frame 4 dosed. This type of bonding requires comparatively much adhesive. Furthermore, the lamellar layer can not reach the holding frame 4 . 5 be introduced, since the space for adhesive dosing is required during assembly. This clearance is also an undesirable bypass for through the lamellar layer 3 durchzuleitende cooling air.

The lower part of 3 shows in the same scale a mirrored upper part of a heat exchanger according to the invention 1 , In this are the front ends 16 the pipes 2 , in particular their longitudinal sides 14 , conically widened and, as in 5 and 6 shown in detail and will be explained below, on appropriately shaped, with an adhesive 12 provided and extending in the cooling air flow direction KL webs 18 the support frame 4 attachable. This makes it possible, as in the lower part of the 3 it can be seen, the lamellar layers 3 to the support frame 4 . 5 can be introduced. As widened under the term "conical" and variants are considered, in which the front ends 16 the pipes 2 a curved shape shape, for example, similar to a Parabelfußes, or even stepped or stepped expanded. Accordingly, in these conceivable variants, the webs 18 the support frame 4 shaped.

4 shows a perspective view of a heat exchanger block 10 , which consists of several, a cooling air surface forming, metallic lamellar layers 3 for passing dry cooling air in cooling air flow direction KL as well as between each of the lamellar layers 3 arranged, forming a process air surface pipes 2 for passing moist process air in the process air flow direction PL exists. The front ends 16 the pipes 2 are flared, preferably at about 10 ° to 30 ° to the cooling air flow direction KL.

The 5 and 6 serve to illustrate the mounting of the pipe ends to the support frame 4 . 5 , The frame 4 . 5 has webs 18 on, the conical walls 19 have in each with the adhesive 12 stuffed gutters 17 lead.

Preferred is in each of the webs 18 the support frame 4 . 5 one parallel to the outer walls of the bridge 18 running inner bridge 20 molded, with the adhesive 12 stuffed gutters 17 through a wall of the inner web and the conically shaped wall 19 are limited. This may cause the adhesive 12 be dosed in a minimum necessary amount.

Preferred are in the conically shaped walls 19 of the bridges 18 pocket-shaped bulges 21 designed for uniform distribution of the adhesive 12 between the jetty 19 and the pipe inner surface 22 after pushing on the pipe end 16 ensure the best possible strength and tightness of this bond.

In 6 is one in the holding frame 4 inserted pipe end shown in the assembled or bonded state. The bridges 19 and the pipe expansion are preferably coordinated so that a good investment of both parts is generated, optionally with a generated by spatial overlapping strain at the ends lying in the pipe opening 26 of the bridges 19 In order to prevent in particular an accumulation of lint in this area effectively.

In 7 is another particular embodiment of a heat exchanger block of a heat exchanger according to the invention 1 shown. In this case, this block is not in one piece from a number x of tubes and a number x + 1 of slats and two side panels 8th by gluing or soldering, but of individual elements 23 formed, each consisting of a tube 24 and two attached to this, in particular glued or soldered lamellar layers 25 consists of stacked the heat exchanger block 10 form.

The 8th shows the in 7 illustrated heat exchanger block in the assembled state. The outermost lamellar layer are by side parts 28 covered, which as in the embodiment described above can be made of sheet metal or, for example, plastic as injection molded or extruded parts. The side parts 28 are preferably loose on the tube-fin elements 23 up and are in the frame 4 fixed by plug or snap connections.

While in the 1 to 7 slat layers shown 3 . 25 are made by punching, are in the 8th to 10 slat layers shown 25a . 25b produced by rolling. As a result, thinner sheets can be used as starting materials for the lamellar layers 25a . 25b deploy. 9 shows an element 23 with a particularly advantageous form of the lamellar layers 25a by adhesive 31 with the pipe 2 connected is. In order for these rolled laminar layers, the heat transfer between the pipe wall 30 and the lamella 25a , at the same time sufficiently high strength of the adhesive bond between pipe and lamella, to make it as optimal as possible, it is important that the lamellae 29 the largest possible contact surface with the pipe wall 30 possess the disadvantage of a comparatively poor thermal conductivity of a preferably organic adhesive 31 to compensate for a metallic solder joint.

Two particularly advantageous variants of a lamellar layer 25a . 25b are in 10 shown. In the case of the lamella 25a with production-related rounded cam shape, the radius r of the cam is sized to be greater than a quarter of the cam pitch NT, but less than two-fifths of the cam pitch NT. In the case of the lamella 25b with a flat cam shape, the width of the cam is greater than half of the cam pitch NT, but less than two-fifths of the cam pitch NT. The total height h of the slats is made up of two superimposed lamellar layers 25a . 25b together, as is in 8th is shown.

Of particular advantage in this design, the cam also that the slats 25a . 25b in the arrangement of the elements 23 one above the other can not slide into each other and get caught, which facilitates the installation of the heat exchanger.

Opposite in the 1 to 6 shown embodiment of the fins are per heat exchanger 1 much more lamellae 29 required to achieve the claimed ratios between the height of the blade and cam pitch NT or cooling air surface and process air area. However, this manufacturing disadvantage is compensated by the fact that the slats 25a . 25b can be produced in a rapid process by rolling and thinner materials can be used. Furthermore, on each slat only one-sided adhesive 31 be applied to connect to the outer wall of the tubes 24 to enable.

LIST OF REFERENCE NUMBERS

1

heat exchangers

2

Tube)

3

Lamellar layer (s)

4

frame

5

frame

6

seals

7

seals

8th

Sheet metal side panel

9

slice

10

heat exchanger block

11

pipe ends

12

adhesive

13

free space

14

Long side of the pipe

15

External surfaces of the slats

16

front ends / pipe end

17

run

18

Stege

19

walls

20

inner web

21

Bulge (s)

22

Pipe inside

23

elements

24

pipe

25

lamellar layers

25a

lamellar layers

25b

lamellar layers

26

End up)

27

heat exchangers

28

Plastic side panel

29

lamellae cams

30

tube sheet

31

adhesive

H

height

NT

cam division

KL

Cooling air flow direction

PL

Process air flow direction

r

Radius of a cam

n

Width of a cam

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0305702 A1 [0005]

Claims (14)

Heat exchanger ( 1 . 27 ), in particular heat exchangers of a condensation tumble dryer, comprising a heat exchanger block ( 10 ), consisting of several, a cooling air surface forming, metal lamellae layers ( 3 . 25 . 25a . 25b ) for passing dry cooling air in a cooling air flow direction (KL), wherein between each of the lamination layers ( 3 . 25 . 25a . 25b ) at least one tube forming a process air surface ( 2 . 24 ) is arranged for the passage of moist process air in a process air flow direction (PL), wherein front ends ( 16 ) of the pipes ( 2 . 24 ) over the edge of the lamellar layers ( 3 . 25 . 25a . 25b ) and in a respective support frame ( 4 protrude and are glued thereto, characterized in that on the respective top and bottom of the tubes ( 2 . 24 ) each a lamellar layer ( 3 . 25 . 25a . 25b ), wherein the ratio between the cooling air area and the process air area is greater than or equal to 7.0. Heat exchanger ( 1 . 27 ) according to one of the preceding claims, characterized in that the ratio between the height of the lamellar layers ( 3 . 25 . 25a . 25b ) perpendicular to the cooling air surface and the cam pitch of the lamellar layers ( 3 . 25 . 25a . 25b ) is greater than or equal to 2.4. Heat exchanger ( 1 . 27 ) according to claim 1 or 2, characterized in that the lamellar layers ( 3 . 25 . 25a . 25b ) on the top or bottom of the tubes ( 2 . 24 ) are glued. Heat exchanger ( 1 . 27 ) according to one of the preceding claims, characterized in that the tubes ( 2 . 24 ) in the region of the lamellar layers attached to them ( 3 . 25 . 25a . 25b ) are stacked loosely on each other. Heat exchanger ( 1 . 27 ) according to claim 3 or 4, characterized in that the lamellar layers ( 25 . 25a . 25b ) are formed as rolled lamellar layers. Heat exchanger ( 27 ) according to one of the preceding claims, characterized in that on the pipe ( 24 ) adhered rounded cam area of the lamellar layer ( 25a ) has a radius (r) between one quarter and two fifths of the cam pitch (NT) of a lamella of the lamellar layer ( 25a ) lies. Heat exchanger ( 27 ) according to one of the preceding claims, characterized in that on the pipe ( 24 ) adhered flattened cam portion of the lamellar layer ( 25b ) has a width (b) between half and three quarters of the cam pitch (NT) of a lamella of the lamellar layer ( 25b ) lies. Heat exchanger ( 1 . 27 ) according to one of the preceding claims, characterized in that the front ends ( 16 ) of the pipes ( 2 . 24 ) are conically widened and shaped accordingly, with an adhesive ( 12 ) and extending in the cooling air flow direction (KL) webs ( 18 ) of the holding frame ( 4 ) are attachable. Heat exchanger ( 1 . 27 ) according to claim 8, characterized in that the flared ends ( 16 ) of the tubes are widened by 10 ° to 30 ° to the cooling air flow direction (KL). Heat exchanger ( 1 . 27 ) according to one of claims 8 to 9, characterized in that the lamellae ( 3 . 25 ) to the conically widened area of the tubes ( 2 ). Heat exchanger ( 1 . 27 ) according to one of claims 8 to 10, characterized in that the webs ( 18 ) of the holding frame ( 4 ) conically shaped walls ( 19 ) in respective ones with the adhesive ( 12 ) filled gutters ( 17 ). Heat exchanger ( 1 . 27 ) according to one of claims 8 to 11, characterized in that in the webs ( 18 ) of the holding frame ( 4 ) each one parallel to the outer walls of the webs ( 18 ) extending inner web ( 20 ) is molded, with the adhesive ( 12 ) filled gutters ( 17 ) by a wall of the inner web and the conically shaped wall ( 19 ) are limited. Heat exchanger ( 1 . 27 ) according to one of claims 8 to 12, characterized in that in the conically shaped walls ( 19 ) of the webs ( 18 ) pocket-shaped bulges ( 21 ) for uniform distribution of the adhesive ( 12 ) between the walls ( 19 ) of the webs ( 18 ) and the inner surfaces of the front ends ( 16 ) of the pipes ( 2 ) are formed. Condensing tumble dryer with a drying drum and a process air for guiding specific circuit with an exhaust air and a supply air duct for the passage of the process air and an intermediate heat exchanger ( 1 . 27 ) for condensing moisture contained in the process air, characterized in that the heat exchanger ( 1 . 27 ) is formed according to one or more of the preceding claims.

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