DE102005005292A1 - A plate heat exchanger for gaseous materials has a number of parallel preformed plates between which the gas is passed and heat exchanging tubes passing transversely through them with heater tubes - Google Patents

Abstract

The lamina plates (1) have a saw-tooth profile and are stacked between mounting plates (5) and heat transfer tubes (7) are pressed through them with connecting U-section tubing (6) in a serpentine manner. Heating tubes (9) also pass through without interconnections to accommodate electric heating elements or heating fluid for defrosting.

Description

The The invention relates to a fin heat exchanger with a number parallel lamellae, which in the operation of the finned heat exchanger for heat exchange serve with a flowing between the slats gaseous medium, and at least a heating tube for receiving a heating element or for passage a heating medium, wherein the heating tube through heating tube openings guided in the slats is a method for producing such a fin heat exchanger and a flaring tool for performing the manufacturing process.

A finned heat exchanger operated as a cooler for a gaseous medium is known in DE 197 09 176 A1 described. A number of generally metallic fins are arranged parallel to each other and is penetrated by one or more heat transfer tubes, here coolant tubes. A coolant flows through the at least one coolant pipe in cooling operation, while a gaseous medium to be cooled flows through the free space between the disks. The heat transfer tubes exchange heat with the fins, which in turn exchange heat with the flowing gaseous medium. In particular, when the finned heat exchanger is used for cooling, frost may form on the fins.

at known solutions For defrosting the slats in a break in operation, a heating medium through the heat transfer tubes cleverly. In other known solutions are parallel to the heat transfer tubes one or more heating tubes provided by heating tube openings guided in the slats are. These heating pipes can either send a heating medium be introduced or a heating rod which, e.g. is electrically heated.

Around sufficient thermal contact between the heating tube and the fins are the heating tube openings in known solutions crimped, leaving a larger area for heat transfer to disposal stands. Nevertheless, it may be during the defrosting process to very high temperatures on the heating tube, e.g. up to 300 ° C. Thereby It can be an undesirable Steam formation during come the defrosting.

It It is the object of the present invention to provide a fin heat exchanger indicate that a good heat transfer while the defrosting guaranteed and a high degree of effectiveness in the heat exchange mode with the pouring gaseous Medium allows. Furthermore, a method and a tool should be specified, with their help, such a fin heat exchanger easily and inexpensively can be.

These Task is with a fin heat exchanger with the features of claim 1, a manufacturing method with the features of one of the claims 5 or 6 or a Aufweitwerkzeug with the features of the claim 12 solved. under claims are directed to preferred embodiments.

at a heat exchanger according to the invention the at least one heating tube is pressed into the heating tube openings of the lamellae. Due to the fixed press fit of the heating tube in the slats is a much improved heat transfer guaranteed. The pressing of the heating tube in the slats can e.g. by widening in the heating tube openings introduced Heating tube happen. With accordingly expanded from inside heating pipes Is it possible, the lamella temperature during to increase the defrosting process at the same heat output and at the same time a lower surface temperature of the heating tube to ensure, without the defrosting effectiveness across from conventional solutions would be reduced or the defrosting efficiency to increase at the same heat output.

The Heizrohröffnungen the fin heat exchanger according to the invention can at their edges crimped be. The heating tube is then in the crimped heating tube openings pressed. It is in a fin heat exchanger according to the invention but surprisingly with hardly any reduced heat transfer efficiency possible, on the flaring the edges the heating tube openings to renounce. Alone by the press fit of the heating pipes in the heating pipe openings is a sufficiently good heat transfer guaranteed. The gaseous Medium that flows between the fins to exchange heat with it, should lose as little pressure as possible on its way through the finned block, by e.g. a fan, which promotes the gaseous medium, if possible little to burden. By dispensing with the flaring the heating tube openings becomes the resistance for the streaming Medium kept lower. Compared to solutions with crimped Heizrohröffnungen let yourself the pressure loss when flowing through reduce the medium by the disk pack by a few percent. Next the considerably simplified production of the slats with heating tube openings without flaring so also the effectiveness of the heat exchange operation the slats with the flowing gaseous Medium increased.

This effect is particularly beneficial when Slats are used, which are structured by slots or embossments to produce turbulent flow.

Finned heat exchanger can of heat transfer tubes be interspersed with the heat replace the slats to this z. B. to cool. It can be about a single heat pipe act that z. B. serpentine led the fins is or around several parallel, individual heat transfer tubes. Likewise individual heat transfer tubes outside the parallel lamellae by appropriate connections to a snake-shaped Be connected pipe. In the present text these alternatives are includes, when generally of heat transfer tubes is spoken. An inventive lamellae heat exchanger can be interspersed in a rectangular grid of heat transfer tubes be. Particularly effective is a heat exchanger in which the heat transfer tubes in the flow direction the medium are arranged offset, in particular when three adjacent Heat transfer tubes each form an approximately isosceles triangle. Is advantageous e.g. a choice such that the ratio between diameter the heat transfer tubes or the one for it provided openings in the slats and the length of the isosceles triangle is between 0.25 and 0.33.

at a preferred embodiment of the fin heat exchanger according to the invention is the at least one heating tube between two heat transfer tubes in alignment arranged. This results in a particularly favorable for the exchange of heat flow of the medium in the space between the lamellae. In addition, in such an embodiment simplifies the manufacture, as a simple cutting of the lamella into the desired size is possible.

at a method according to the invention for producing a laminated heat exchanger according to the invention is the at least one heating tube through aligned heating tube openings the lamellae of a disk pack inserted, consisting of a number in parallel arranged lamellae arranged between parallel thereto End plates are arranged with corresponding aligned openings. The End plates are more stable and thicker than the slats yourself and point with the openings in the slats aligned openings on.

Already before plugging in or after insertion, the at least a heating pipe on one side a little bit on its front face, so that the edge is no longer through the openings in the end plate can slip. A Heizrohraufweitstößel is by the at least one Heating pipe encountered, so that the heating tube is widened within the heating tube openings of the slats and in the heating tube openings is pressed. As Heizrohumaufweitstößel can e.g. a spherical element be used.

With the method according to the invention for the production of a finned heat exchanger the press fit of the at least one heating tube is easy and inexpensive too realize. By the bulge of the edge of the heating tube can on elaborate Holding steps during piercing dispensed with the Heizrohraufweitstößels become.

The Auftulpen can be a separate step or by the Impact of the plunger at piercing the ram through the heating tube are effected.

at another method of the invention for producing a laminated heat exchanger according to the invention, for the independent protection is claimed, the at least one heating tube is also through aligned heating tube openings the slats of a disk pack inserted, consisting of a number arranged in parallel slats. A Heizrohraufweitstößel is bumped through the at least one heating tube to the heating tube within the heating tube openings widen and so to press in the heating tube openings. at this method according to the invention the widening step thus effected is simultaneous with widening of at least two heat transfer tubes carried out. By the simultaneous expansion of the heating tube and the heat transfer tubes can individual Aufweitschritte be saved. Moreover, by the simultaneous Expansion of the heat transfer tubes and the heating tube a higher stability while piercing ensures the or the plunger. The manufacturing process is safer and more precise in this way.

Especially Cheap is a combination of the two methods according to the invention, in which both the edge of the at least one heating tube is opened, as well widened at least two heat transfer tubes simultaneously with the heating tube become.

The expansion can be carried out particularly stably if the ends of at least two heat transfer tubes projecting out of the disk pack are held by encompassing grippers. At the end of at least one of the gripped heat transfer tube, a heat transfer tube tappet is attached and on a protruding from the disk set aufgegetulptes end of at least one heating tube a Heizrohraufweitstößel. The at least one heat transfer tube plunger and the at least one heating tube Aufweitstößel are simultaneously pushed through the respective tubes to expand both the heat transfer tubes and the at least one heating tube and so to press in the openings of the slats.

to Further simplification of the method can be provided that the bulge of the edge of the at least one heating tube through the Placing the Heizrohumufweitstößels causes becomes.

Especially Cheap and it is stable when such heat transfer tubes widened simultaneously with the at least one heat transfer tube which are in direct proximity to this heating tube. Especially is it cheap if two heat transfer tubes be widened together with a heating tube, which with the heating tube are in a line and arranged on opposite sides thereof are.

Especially it is effective when the method according to the invention is used, to expand several heating pipes at the same time.

One Inventive expansion tool is used the simultaneous expansion of at least one heating tube and at least two heat transfer tubes. For this purpose, the expansion tool on at least two grippers, the are configured such that they the ends of heat transfer tubes, which protrude from a disk pack, can embrace and one heat transfer tube plunger inside each the gripper guided can be. The expansion tool according to the invention has a Heizrohraufweitstößel on which between two such grippers is arranged. The heating pipe extension ram and the heat transfer tube tappets are so interconnected that they simultaneously by the at least a heating tube and the heat transfer tubes be encountered can.

One Spreader tool according to the invention spared the need to widen individual tubes separately. Especially in embodiments, at those the heating pipes and the heat transfer pipes Are aligned with each other, the space-saving solution of expansion tool according to the invention advantageous. In particular, there is no gripper for the end of the widening Heating tube necessary.

Especially can in a flaring tool according to the invention provided with several heat transfer rams be that individual of these heat transfer rams on the joint expansion process does not participate and for this purpose can be turned off. Likewise, in a widening tool with several Heizrohraufweit provided tappets be that individual Heizrohumufweitstößel be turned off in such a way that they do not participate in the common expansion process. With Such widening tools designed in this way is an individual Adaptation of the tool to the laminated fin to be manufactured just possible.

preferred Embodiments of the invention will be with reference to the accompanying figures explained in detail. Showing:

1 in a schematic representation of a section of a disk pack according to the invention in a lateral plan view,

2 a side perspective view of a section of a disk pack in a schematic representation,

3 a section of a slat in plan view,

4 a lateral plan view of the slat of 3 in the viewing direction IV,

5 an inventive expansion tool and

6 a gripper of such expansion tool.

The disk pack of the 1 consists of a large number of usually metallic lamellae 1 which are arranged parallel to each other. In 1 only a few of these fins are shown. The point row F is intended to indicate that the space between the end plates 5 even with lamellae 1 is filled. The end plates 5 are stable and thicker than the slats and provide a mechanical finish. The finned heat exchanger 3 is not drawn to scale and can be much longer, for example. This should be indicated by the break lines B.

Through the disk pack go several heat transfer tubes 7 , At joints, eg solder joints 8th are the heat transfer tubes 7 over connectors 6 connected snake-shaped. If the finned heat exchanger is a cooler, the heat transfer tubes are used 7 as coolant tubes. Between the heat transfer tubes 7 are heating pipes 9 inserted through the disk pack. They are at one end with a bulge 11 Mistake. The heating pipes 9 are metallic and serve in the embodiment shown for receiving electrically operated heating elements, which in 1 not ge shows are. With the heating rods, frost that occurs in the cooling mode of the finned heat exchanger can be defrosted by the fins. Both the heat transfer tubes 7 as well as the heating pipes 9 are through corresponding openings in the slats 1 and the end plates 5 guided. In the manner described below, the heat transfer tubes 7 and the heating pipes 9 by internal expansion in the corresponding openings of the slats 1 pressed.

2 shows a particular embodiment of the slats 1 in an enlarged view. In the embodiment of the 2 are the slats 1 embossed. For the sake of clarity, the heat transfer tubes and the heating tubes are not shown here. The flow 17 which flows through the spaces between the slats to heat to the slats len 1 is deflected by the embossing and tears at the tips 13 from. This creates a turbulent flow pattern that must first be applied to the lamellar surface again. In this renewed approach process, heat is transmitted particularly effectively. In contrast to a solution with slots for generating turbulent flow, there is no danger of clogging due to frost formation here.

The Period P of embossing and the imprint height PH in the embodiment chosen so that the quotient of the imprint height and the Period between 0.2 and 0.25. The imprint height PH should be used to generate an optimal tear-off effect greater than 2 mm, for a flow velocity from 1.5 to 3.5 m / s e.g. between 2.2 mm and 2.4 mm. The distance A of the individual fins to each other is at said flow rate advantageously between 3 and 8 mm, in particular in a range of 4 mm to 6 mm.

As a rule, there are two points pointing upwards 13 a lamella a down-facing jag 13 , Between individual prongs is in the embodiment shown, a narrow horizontal area 15 For example, to ensure as unhindered drainage of condensation water from the lamella.

3 shows the top view of a blade of a heat exchanger according to the invention. Visible are heat transfer tube openings 19 and heating tube openings 21 , As in other figures, are several existing features, so here, for example, the heat transfer tube openings 19 , not necessarily individually provided with reference numerals.

Visible is the staggered arrangement of the heat transfer tube openings 19 with respect to the flow direction 17 of the medium. Three heat transfer tube openings 19 Each form an isosceles triangle, wherein in the illustrated embodiment, the ratio between the diameter of a heat transfer tube and a heat transfer tube opening 19 and the length of a leg of the triangle is between 0.25 and 0.33. Between every two heat transfer tube openings 19 whose connecting line is oblique to the flow direction 17 is aligned, there is in each case a heating tube opening 21 ,

R denotes a region of the lamella, which coincides with a expansion tool according to the invention can be treated, as will be described below.

In the lateral plan view of 4 , in the 3 Drawn with IV, it can be seen that the heating tube openings 21 have no flaring of the edges. In contrast, this embodiment shows flared edges 20 at the heat transfer tube openings 19 ,

5 shows a widening tool, as it can be used to expand heating tubes and heat pipes, through corresponding openings 19 . 21 a section of a disk pack can be used, as he the example of a single slat in 3 is denoted by R. The total with 30 designated tool includes gripper 31 , with which five heat transfer tubes 7 can be taken, which protrude laterally from a disc pack and in a through the heat transfer tube openings 19 in the slats 1 predetermined grid are arranged. To grip around are the grippers 31 slotted at their ends. Slide on a plug-on tube 33 from behind on the slotted ends of the grippers 31 causes it to reduce its inner circumference and a tube that fits in a gripper 31 is taken from the outside. 35 denotes a Heizrohraufweitstößel for expanding a heating tube in a heating tube opening 21 , Within each gripper 31 is located in each case a heat transfer tube plunger for expanding a heat transfer tube 7 in the openings 19 which is not recognizable in the figure. The heat transfer tube plungers and the heating tube extension plunger 35 can eg by a common carrier plate 37 be held.

6 shows by way of illustration the gripper part 31 isolated. Here is especially good one of the slots 39 to recognize, located in the front end of the gripper 31 are located.

The finned heat exchanger 3 The embodiment shown is made as follows. The slats 1 are arranged parallel to each other and at a distance A of, for example, 4 mm to 6 mm in held in a known manner. In the slats are already the heat transfer tube openings 19 with a border beading 20 and the heating tube openings 21 without edge beading. The flaring 20 The heat transfer tubes can eg as a spacer between the individual slats 1 act. By the disk pack thus formed become heat transfer pipes 7 and heating pipes 9 pushed. The diameters of the openings are chosen so that the tubes 7 . 9 can be easily introduced.

Not necessarily all heating tube openings 21 are provided with heating pipes. For an effective defrosting process after frost formation on the slats 1 it is not necessary that any of the heating tube openings 21 is provided with a heating tube and can be heated. The nevertheless larger number of heating tube openings 21 However, ensures an improved turbulent flow during operation of the heat exchanger 3 ,

The expansion tool 30 is so to a end plate 5 introduced that the five grippers 31 on five heat transfer tubes 7 can attack. Moving the Aufsteckrohre 33 towards the ends of the grippers 31 guides the individual through slots 39 separate segments of the gripper 31 in their end area together, leaving the heat transfer tubes 7 be included. The result is a stable connection between the expansion tool 30 and the gripped heat transfer tubes 7 of the disk pack.

The heat transfer tube plunger inside the gripper 31 and the Heizrohraweitungsstößel 35 are connected to each other and are simultaneously pushed in the direction of the disk pack. In particular, the Heizrohraufweitstößel 35 meets the edge of the heating tube 9 and sculpt this slightly, leaving a bulge 11 forms. Upon further movement of the Heizrohraufweitstößels 35 in the direction of the disk pack, the heating pipe gives way 9 far enough, until the bulge 11 at the end plate 5 hits and stops. Another movement of the heating tube expansion ram 35 drives this into the heating tube 9 and leads to a widening within the heating tube openings 21 , The heating tube 9 So it is from the inside against the heating tube openings 21 pressed.

Simultaneously with the heating pipe extension ram 35 Be the ones in the grapples 31 located ram through the heat transfer tubes 7 bumped and lead to their expansion in the heat transfer tube openings 19 the individual slats 1 ,

Similarly, multiple groups of tubes are made using the expansion tool 30 treated until all desired tubes are expanded.

Of course, the invention is not limited to the special expansion tool of 5 limited. Other arrangements of grippers and heating tube expansion rams may also be provided. 5 shows a tool for the simultaneous treatment of a heating tube and a maximum of five heat transfer tubes. There may also be a larger number of grippers and tappets for the simultaneous treatment of a larger number of tubes.

In particular, it can be provided that individual heat transfer rams or individual Heizrohraufweitstößel can be set, turned off or removed so that they do not participate in the common expansion process. For example, it can also be stipulated that a heating pipe expansion ram does not participate in the expansion process if it would be effective in a common expansion process at a location where there is a heating pipe opening 21 is provided, but no heating tube is inserted. On the other hand, the expansion tool according to the invention in this way is so flexible that, for example, always such heat transfer tubes are expanded simultaneously, which are already connected to one another as a hairpin on one side. This ensures that a possibly occurring change in length due to the expansion process is the same for the two heat transfer tubes connected as a hairpin.

The inventive method using the expansion tool according to the invention 30 thus allows the simultaneous expansion of several tubes of a fin heat exchanger. In particular, even if the heating tubes arranged between two heat transfer tubes are to be widened simultaneously, the method according to the invention and the expansion tool according to the invention offer the advantage of stable handling. For the expansion of the heating tube no own gripping mechanism is necessary, which would be problematic in the cramped conditions.

After the expansion step, the individual heat transfer tubes are in a conventional manner 7 with elbows 6 eg by soldered seams 8th z. B. connected to a queue, insofar as this is not already done on the side on which the plunger and gripper, not already before the expansion process.

In operation as a cooler flows through the heat transfer tubes 7 and the connectors 6 in a conventional manner, a coolant. The gaseous medium to be cooled is z. B. with a fan in the direction 17 through the spaces between the slats 1 cleverly. There is heat to the slats 1 This is promoted by the turbulent flow, which at the serrations 13 of the slats 1 arises. The fins give the heat thus absorbed to the heat transfer tubes 7 and the cooling medium flowing therethrough.

In that not every heating tube opening 21 is provided with a heating tube and no flaring is provided, the gaseous medium is on its way between the slats 1 slowed down so that a fan that drives the gaseous medium has a lower power consumption.

Is it necessary to use the slats 1 defrost, so the cooling operation is interrupted and sent no more cooling medium through the heat transfer tubes. By individual heating pipes 9 Heating rods are pushed or are already provided firmly inserted. The heating elements are electrically heated and lead to a heating of the heating pipes 9 , Due to the interference fit of the heating pipes in the slats 1 the heat energy is particularly effective on the fins 1 that are effectively defrosted. Due to the interference fit, the heat transfer is so good that no excessive heating of the heating pipes is necessary and unwanted vapor formation is reduced or avoided.

1

lamella

3

Finned heat exchanger

5

End plate

6

Connecting pipe piece for heat transfer pipes

7

Heat pipe

8th

soldered seam

9

heating pipe

11

tulip-shaped section

13

Pink the lamella embossing

15

horizontal Area of lamella embossing

17

Flow of gaseous medium

19

Heat transfer tube opening

20

Edge flange

21

Heizrohröffnung

30

flaring

31

grab

33

Extension tube

35

Heizrohraufweitstößel

37

support plate

39

gripper slot

Claims (13)

Laminated heat exchanger with a) a number of parallel lamellae, which serve in the operation of the finned heat exchanger for heat exchange with a flowing between the slats gaseous medium, and b) at least one heating tube for receiving a heating element or for passing a heating medium, wherein the heating tube through heating tube openings in the Slats is guided, characterized in that the at least one heating tube ( 9 ) in the heating tube openings ( 21 ) of the slats ( 1 ) is compressed. Laminated heat exchanger according to claim 1, characterized in that the heating tube openings ( 21 ) for the at least one heating tube ( 9 ) are not flared at their edges. Laminated heat exchanger according to one of claims 1 or 2, characterized in that the lamellae ( 9 ) in each case several times from one or more heat transfer tubes ( 7 ) are interspersed, the heat exchange of the slats ( 1 ) with a heat exchange medium which, during operation of the finned heat exchanger ( 3 ) in the heat transfer tubes ( 7 ), with three adjacent heat transfer tubes ( 7 ) each form an approximately isosceles triangle. Laminated heat exchanger according to claim 3, characterized in that the at least one heating tube ( 9 ) in alignment between two heat transfer tubes ( 7 ) is arranged. A method of manufacturing a fin heat exchanger according to claim 1, wherein the at least one heating tube ( 9 ) through the heating tube openings ( 21 ) of the slats ( 1 ) a lamella packet is inserted, which consists of a number of parallel slats ( 1 ), which between parallel arranged end plates ( 5 ) are arranged, the at least one heating tube ( 9 ) before or after insertion at a front edge ( 11 ) and a heating tube extension ram ( 35 ) through the at least one heating tube ( 9 ) is pushed around the heating tube ( 9 ) within the heating tube openings ( 21 ) and so in the heating tube openings ( 21 ) to be pressed. A method in particular according to claim 5, for producing a laminated heat exchanger according to claim 1, wherein the at least one heating tube ( 9 ) through the heating tube openings ( 21 ) of the slats ( 1 ) a lamella packet is inserted, which consists of a number of parallel slats ( 1 ), a Heizrohraufweitstößel ( 35 ) through the at least one heating tube ( 9 ) is pushed around the heating tube ( 9 ) within the heating tube openings ( 21 ) and so in the heating tube openings ( 21 ), wherein the at least one heating tube ( 9 ) simultaneously with at least two heat transfer tubes ( 7 ), which is used for heat exchange of the fins ( 1 ) with a heat exchange medium which, during operation of the finned heat exchanger ( 3 ) in the heat transfer tubes ( 7 ) flows. Method according to claim 6, wherein a number of heat transfer tubes ( 7 ) through heat transfer tube openings ( 19 ) are inserted in the disk pack, with a corresponding number of grippers ( 31 ) at ends which protrude from the disk pack, to at least one gripped end of a heat transfer pipe ( 7 ) a heat transfer tube tappet is attached, a Heizrohraufweitstößel ( 35 ) on a protruding from the disk pack, aufgegetulptes end ( 11 ) of at least one heating tube ( 9 ), and the heat transfer tube plungers and the Heizrohraufweitstößel ( 35 ) simultaneously through the heat transfer tubes ( 7 ) or the at least one heating tube ( 9 ) are pushed to the heat transfer tubes ( 7 ) and the at least one heating tube ( 9 ) and so in the openings ( 19 . 21 ) of the slats ( 1 ) to be pressed. Method according to claim 7, in which the warming-up of the at least one heating tube ( 9 ) simultaneously with the placement of the Heizrohraufweitstößels ( 35 ) on the heating tube ( 9 ) happens. Method according to one of claims 7 or 8, in which at least such heat transfer tubes ( 7 ) simultaneously with the at least one heating tube ( 9 ) are widened, the at least one heating tube ( 9 ) are adjacent on several sides. Method according to claim 9, wherein at least two heat transfer tubes ( 7 ) simultaneously with the at least one heating tube ( 9 ), whereby the heating tube ( 9 ) between the two heat transfer tubes ( 7 ) is arranged. Method according to one of claims 5 to 10, wherein a plurality of heating tube expansion rams ( 35 ) simultaneously by a corresponding number of heating tubes ( 9 ) is encountered. Expander tool for carrying out a method according to claim 7, with at least two grippers ( 31 ) which are designed such that they have ends of heat transfer tubes ( 7 ), which protrude from a disc pack, can surround at least two heat transfer tube plungers which are located inside the grippers ( 31 ), and at least one Heizrohraufweitstößel ( 35 ) between two grippers ( 31 ), wherein the at least one Heizrohraufweitstößel ( 35 ) and the heat transfer tube plunger are connected to each other in such a way that they simultaneously through the at least one heating tube ( 9 ) and the heat transfer tubes ( 7 ) can be encountered. An expansion tool according to claim 12, wherein at least one of the heat transfer rams and / or at least one of the Heizrohraufweitstößel adjustable so switched off or is removable, that he does not at the simultaneous expansion process participates.