EP0578933B2 - Welded plate type heat exchanger - Google Patents

Abstract

Plate heat exchanger in which all the plates (1) are welded to one another, for which purpose the plates (1) have along their outer circumference two mutually offset edge regions (3, 4) and likewise mutually offset inlet and outlet openings (2) via which they are welded alternately to one another. <IMAGE>

Description

The invention relates to a plate heat exchanger with several profiled, essentially rectangular plates with inlet and outlet openings in the corner areas, which are arranged in a stack such that flow spaces alternating with a first between the plates and can be charged to a heat-exchanging second medium, the plates being joined together by welding and facing each other the environment are sealed and the plate profiling is formed on both sides of the plates and accordingly on both sides apex planes forms.

Welded plate heat exchangers have compared to the heat exchangers with removable plates the advantage that on the elastic seals can be dispensed with between the plates. Therefore welded Plate heat exchangers with higher temperatures and pressures as well as operated with more aggressive media than heat exchangers with seals. Beyond that there are no malfunctions due to leaking and therefore replaceable seals fear.

Through the English patent applications 2 126 703 and 2 167 175 welded plate heat exchangers known in which the spacing and welding of adjacent panels using separate sealing strips made of metal. These sealing strips are made accordingly the desired flow admission to one Plate welded, then the neighboring plate is aligned accordingly and in turn welded onto these metal strips. Regarding of the latter welding process, it is necessary in each case weld the top plate through. So that there is no damage here of the weld connection previously made, the Sealing strips in successive flow spaces can be arranged offset relative to each other. All of this leads to very high manufacturing costs for these plate heat exchangers.

From GB-1 580 368 a plate heat exchanger is known, the Plates are angled several times along their outer circumference, so that a staggered first peripheral area running parallel to the plate have, with the one apex plane of the plate profiling aligned and a second offset peripheral area parallel to this, the one with the other apex plane of the panel profiling is aligned, with the inlet and outlet opening of each plate equally for the one medium have ring surfaces which are approximately - preferably exactly - to the one apex plane, while the in and Have outlet opening for the other medium ring surfaces that approximately - preferably exactly - are offset from the other apex plane, and that two adjacent plates continuously along the adjacent first edge areas and along the ring surfaces are welded to a cassette while adjacent cassettes continuously along the adjacent second edge areas and are welded along the ring surfaces.

However, this design has a number of disadvantages: First on the one hand, the welding of adjacent plates or cassettes along the ring surfaces a very high precision, both what the mutual Positioning as well as regarding the welding process itself, which makes the production correspondingly more complex and expensive becomes. In addition, the ring surfaces form sharp-edged for the flow Inlet and outlet openings, resulting in stalls and thereby Flow and heat transfer losses in this area leads. On the other hand there is also the successive welding adjacent plates along the first edge areas and welding adjacent cassettes along the second edge areas disadvantageous: because on the one hand there is a connection between neighboring ones Flatten the danger that the position of the second is only afterwards edge areas to be welded - for example by Faults - something that changes, especially with regard to the Double fit through the ring surfaces on the one hand and the second edge areas on the other hand, problems and inaccuracies when connecting adjacent cartridges can lead. On the other hand, the gaps form between the first edge areas and the outside offset second edge areas with low flow dead spaces, which also have a negative impact on the quality of heat transfer.

It is also known from US Pat. No. 5,125,453 for plate heat exchangers to provide bending elements adjoining the ring surfaces, leave the longer peripheral areas of the openings free. Indeed the plates are mutually vacuum vacuum soldered to each other connected.

Finally, GB-A 1 223 752 shows a plate heat exchanger at the adjacent plates are welded on the end face via U-shaped spacers while they are on their longitudinal sides perpendicular to this are directly connected to each other via folds.

The present invention has for its object a plate heat exchanger specify where all the panels are welded together are, however, compared to the prior art distinguishes much cheaper production.

This object is achieved by a heat exchanger with the features of claims 1 or 2.

In this way, there is no need to attach separate sealing strips. Rather, only the plate edges lying against each other need each other to be welded, what given the thin wall thickness the plates don't cause any problems. It is essential that through the targeted offset of the ring surfaces and, if necessary, the turns at the inlet and outlet openings there too without additional Measures the welding necessary to separate the product streams longitudinally adjacent plate areas is possible.

In addition, the design according to the invention has the advantage that all plates can be shaped identically, that is, for the whole Heat exchanger only one type of stamp is necessary. To make the Cassettes only need the plates rotated 180 ° against each other to be so that they lie in pairs back to back come.

From a fluidic point of view, it is particularly favorable if the ring surfaces are on one side of the longitudinal axis of the plate opposite to the ring surfaces are offset on the other side of the longitudinal axis of the plate. The Plates then have to be rotated about their transverse axis and the media mainly flow in the counterflow direction. Of course lies but it is also within the scope of the invention, the ring surfaces relative to To move the transverse plate axis.

In all cases it is recommended that the edge areas as well as the The ring surface of each plate is flat so that a problem-free, tight welding is guaranteed.

A particularly expedient embodiment of the invention consists in that the turns following the ring surfaces are about are arranged perpendicular to it and that these turns alternately are directed so that the plates that make up a common cassette form, each have pluggable bends. Thereby the plates of a cassette no longer need inside the plate hole be welded, but from the top of the plate, the better is accessible and visible. The welding is therefore easier and at the same time more reliable.

It is particularly advantageous if the bends to be plugged together two plates are of different lengths, such that the free edges the turns are aligned when plugged together. Thereby welding is made even easier.

With this design, each plate has a wide top and a slightly larger one less protruding turn and below as well.

The first edge area along which the plates form a cassette to be welded is appropriate by a perpendicular to the plate plane circumferential intermediate piece connected to the second edge area, along which the cassettes are welded together. Thereby the marginal areas immediately follow one another outward and one receives a compact structure of the plate.

Figur 1

drei im oberen Lochbereich geschnittene Platten in Schrägansicht gemäß einer ersten Bauform;

Figur 2

die Draufsicht auf eine solche Platte;

Figur 3

eine schematische Seitenansicht durch einen Stapel solcher Platten;

Figur 4

eine Ansicht von oben auf diesen Stapel und

Figur 1a bis Figur 4a

die gleichen Ansichten wie die zuvor genannten Figuren bei einer zweiten Plattenbauform.

Further features and details of the invention emerge from the following description of exemplary embodiments with reference to the drawing; shows

Figure 1

three obliquely cut plates cut in the upper hole area according to a first design;

Figure 2

the top view of such a plate;

Figure 3

a schematic side view through a stack of such plates;

Figure 4

a top view of this stack and

Figure 1a to Figure 4a

the same views as the aforementioned figures for a second plate design.

The heat exchanger plates 1 of both designs have in common that they at their four corners each have an opening 2 for the inlet and outlet of the have heat-exchanging media and that the field between them Openings with waves 8 is profiled. These waves 8 are symmetrical arranged with respect to the plate level, so stand around on both sides the same measure before.

In addition, both designs have in common that the plates of one first edge area 3 are surrounded, this edge area to the an apex plane of the shafts 8 is offset, at least as far as the waves 8 protrude. By the same measure there are two of the four openings 2 in the one apex plane of the shafts 8 and two other openings in the other apex plane of the shafts 8 transferred. The openings 2 are each of an annular surface 5 or Surround 9 that join this offset.

In relation to the front plate in FIG. 1, the two are in the left Plate half arranged openings, only the top of which is visible, with its ring surfaces 9 as well as the first edge region 3 offset to the front, whereas the two are arranged in the right half of the plate Openings, of which only the upper one is visible, are offset with their ring area 5 to the rear.

In this respect, both plate designs are the same.

In the plate design according to Figures 1 to 4 follows the An approximately cylindrical bend in each case on the inner edge of the ring surfaces 5 and 9 5a or 9a. The size and direction of these turns are like this chosen that with two plates, with which a cassette is formed should, the bends at openings 2 or 3 that have no passage to the space between the plates should be slidably inserted into each other are and that then the free edges of the turns in mated Condition aligned with each other. This allows this Bends easily and reliably welded from the top of the plate will.

In addition, the inner edge region 3 is connected via a vertical A second edge area running right around the plate level 4, which, however, runs in the opposite vertex plane like the edge area 3.

The connection of this plate design takes place as follows: To the rear one Heat exchange plate 1 in Figure 1 becomes a similar heat exchange plate - but with opposite turns - in reverse orientation, that is, rotated 180 ° around the transverse axis. Then lie both plates, i.e. the rear and the middle, along the first edge area 3 and along the two ring surfaces 9 and the extending into each other Bends 9a to each other and are along the edge area 3 and butt welded together at the edge of the bends 9a. This creates a first cassette with a flow channel 6 as shown in Figures 1, 3 and 4.

Additional cassettes made in the same way are then turned back Put the backs together and weld them along the adjacent ones outer edge areas 4 and the nested Bends 5a welded together, the intermediate cassette channel 7 arises. This continues until the plate stack has the desired size, roughly corresponding to FIG. 3 and 4. Instead, it is also possible to make all the cassettes first, by the edge areas 3 and bends 9a of all plate pairs are welded together and later all the cassettes along the to weld outer edge regions 4 and the bends 5a.

It is also possible instead to weld one plate at a time, in each case along the turns 5a and 9a and along the edge areas 3 and only at the end the complete plate package to be welded along the outer edge regions 4.

FIGS. 3 and 4 show sections through the plate pack according to FIG 1, wherein for the sake of simplicity no turns 5a and 9a are shown are.

The other plate design according to Figures 1a to 4a differs by the fact that the second edge region 4 is dispensed with So plates with the first edge area 3 leak and that the connection adjacent cassettes by interposed U-profiles 10 take place, cf. Figure 1a. These U-profiles 10 are dimensioned so that they are in the space between the edge areas 3 of adjacent cassettes fit flush so that their thighs lightly with these edge areas can be welded.

With this design, the plates do not need to be individually welded together be, but there is the advantageous possibility that Place panels and U-profiles on top of each other and two panels each, which form a cassette and two U-profiles on both sides in one welding together in a single operation.

The plate heat exchanger is most conveniently assembled in such a way that two panels that belong together are placed one on top of the other so that, for example, the bends 5a are nested, that then the turns at both openings simultaneously 5a are welded together, that a U-profile frame 10 and the third heat exchanger plate is placed, so that their turns 9a with the corresponding turns 9a the second plate and then the bends 9a are welded together. This process is repeated with placing the fourth plate, which in turn with the turns 5a is inserted and welded. If the complete plate package all outer edges are welded to the openings in this way welded.

With this type of construction there is also the possibility of the bends 5a and 9a and instead the welding along the adjacent Make ring surfaces 5 or 9. This variant is shown in Figures 1a to 4a.

This weld is somewhat problematic in terms of accessibility, but offers the advantage that the entire heat exchanger can be assembled from absolutely identical panels, whereas one in the embodiment described above two slightly different plate types needed because the turns once project forward, backward once and with different lengths have to. In practice, this is of little importance. Therefore, the Welding over the bent edges 5a or 9a also with the Construction according to Figures 1a to 4a can be used advantageously.

Claims (12)

1. Plate-type heat-exchanger with a plurality of profiled, essentially rectangular plates with inlet and outflow openings in the corner regions which are so arranged into a stack that flow spaces between the plates may be charged alternately with a first medium and with a second medium in heat exchange therewith, wherein the plates are connected together by welding and are sealed from the environment, and wherein the profiling of the plates is formed on both sides of the plates and accordingly forms peak planes on both sides, wherein along their outer periphery the plates (1) are multiply bent so that they have a first, offset peripheral edge region (3) parallel to the plate and aligned with one of the peak planes of the plate profiling (8), and a second offset peripheral edge region (4) which extends parallel to the first edge region and which is aligned with the oppositely lying peak plane of the plate profiling (8) and wherein in equal measure the inlet and outflow openings (2) of each plate have annular surfaces (9) for one of the media which surfaces are offset approximately to the first-mentioned peak plane of the plate profiling, while the inlet and outflow openings (2) for the other medium have annual surfaces (5) offset approximately to the other peak plane,
      characterised in that
      in each case two adjacent plates are continuously welded together into a box structure along the first edge regions (3) bearing against each other and along bent parts (9a) adjoining the annular surfaces (9), while adjacent box structures are continuously welded together along the second edge regions (4) lying against each other and along bent parts (5a) adjoining the annular surfaces (5).
2. Plate-type heat-exchanger with a plurality of profiled, essentially rectangular plates with inlet and outflow openings in the corner regions which are so arranged into a stack that flow spaces between the plates may be charged alternately with a first medium and with a second medium in heat exchange therewith, wherein the plates are connected together by welding and are sealed from the environment, and wherein the profiling of the plates is formed on both sides of the plates and accordingly forms peak planes on both sides, wherein along their outer periphery the plates (1) are multiply bent so that they have a first, offset peripheral edge region (3) parallel to the plate and aligned with one of the peak planes of the plate profiling (8), and wherein in equal measure the inlet and outflow openings (2) of each plate have annular surfaces (9) for one of the media which surfaces are offset approximately to the first-mentioned peak plane of the plate profiling, while the inlet and outflow openings (2) for the other medium have annular surfaces (5) offset approximately to the other peak plane,
      characterised in that
      in each case two adjacent plates are continuously welded together into a box structure along the first edge regions (3) bearing against each other and along the annular surfaces (9) or the bent parts (9a) adjoining the annual surfaces, and in that the welding together of adjacent box structures takes place along the annual surfaces (5) or the bent parts (5a) adjoining them as well as via a peripheral, inserted profiled member (10) of approximately U-shape the two limbs of which bear against at the mutually spaced apart sides of the first edge region (3) and which is continuously welded together with these sides.
3. Plate-type heat-exchanger according to claim 1 or 2,
      characterised in that
      all plates (1) have an identical shape but are alternately angularly displaced by 180°.
4. Plate-type heat-exchanger according to claim 1 or 2,
      characterised in that
      the annular surfaces (5) on one side of the longitudinal axis of the plate are offset oppositely to the annular surfaces (9) of the opposite side of the longitudinal axis of the plate.
5. Plate-type heat-exchanger according to claim 1 or 2,
      characterised in that
      the mentioned edge regions (3, 4) of each plate are flat.
6. Plate-type heat-exchanger according to claim 1 or 2,
      characterised in that
      the two annular surfaces (5, 9) of the openings (2) are flat.
7. Plate-type heat-exchanger according to claim 1 or 2,
      characterised in that
      the bent parts (5a, 9a) extend approximately perpendicularly to the annular surfaces (5, 9) and the plates of a box structure have respective bent parts (5a, 9a) that can be fitted into each other.
8. Plate-type heat-exchanger according to claim 7,
      characterised in that
      the plate of a box structure lying at the rear relative to the bend has longer bent parts such that the free edges of the bent parts are aligned with each other in the fitted-together condition.
9. Plate-type heat-exchanger according to claim 7 or 8,
      characterised in that
      the plates are identically profiled but are divided into two types of plates relative to the direction of the bend of the bent parts.
10. Plate-type heat-exchanger according to claim 1,
       characterised in that
       the two edge regions (3, 4) are connected together by way of an intermediate piece extending peripherally at a right angle to the planes of the plates.
11. Plate-type heat-exchanger according to claim 2,
       characterised in that
       the profiled member (10) is a prefabricated frame.
12. Plate-type heat-exchanger according to claim 1 or 2
       characterised in that
       the weld seams are formed as frontal seams along the bent parts (5a, 9a) and along the edge regions (4) or along the edge regions (3) and profiled parts (10).

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