Plate heat exchanger with reinforced covers and method for the production of said reinforced covers and their assembly

Abstract

A plate heat exchanger includes a pack of superimposed heat exchanger plates, and has two cover plates mounted on the side portions of the first heat exchanger plate. The surface area of each of the two cover plates is smaller than half of the surface area of said first heat exchanger plate.

Claims

1. A plate heat exchanger (1) comprising: a pack (10) of superimposed heat exchanger plates (101) provided with alternating ridges (102) and depressions (103), said alternating ridges and depressions defining, together with the ridges (102) and depressions (103) present on another facing heat exchanger plate (101), circuits for the heat exchange fluids, and through-holes (104) configured to convey two of the heat exchange fluids in spaces between the heat exchanger plates following at least two hydraulically isolated circuits, wherein each heat exchanger plate (101) is rectangular in shape, wherein the heat exchanger comprises two cover plates (21, 22) mounted on a first one (107) of said heat exchanger plates (101), wherein a surface area of each of said two cover plates (21, 22) is smaller than half the surface area of said first heat exchanger plate (107) and wherein each of said two cover plates (21, 22) further comprises: a pair of second holes (23, 231) shaped and positioned to correspond to said through-holes (104) in the heat exchanger plates; and a metal ring (3, 3′), positioned to surround one of said second holes (231) and on a lower area of said first heat exchanger plate (107) where one of the through-holes (104) for one of the heat exchange fluids is made, wherein said metal ring (3, 3′) is adapted to guarantee a hermetic seal between one of said cover plates (21 22) and said first heat exchanger plate (107).

2. The plate heat exchanger (1) according to claim 1, wherein an edge (232) of the one of said hole (231) in one of said cover plates (21, 22) is bent towards one side of the one of said cover plates (21, 22), forming said metal ring (3′) in a single solid piece with the one of said cover plates (21, 22).

3. The plate heat exchanger (1) according to claim 2, wherein the edge of said metal ring (3′) is further bent outwardly to form a flange (3 G).

4. The plate heat exchanger (1) according to claim 1, wherein a shape and size of said two cover plates (21, 22) correspond to side portions of said first heat exchanger plate (107), the side portions comprising said through-holes (104) and being located in proximity to the transverse edges (16).

5. The plate heat exchanger (1) according to claim 4, wherein each of said two cover plates (21, 22) has a symmetrical shape, so that each of said two cover plates can be mounted either on a right side or a left side of the pack (10).

6. The plate heat exchanger (1) according to claim 1, wherein each of said two cover plates (21, 22) comprises one or more shaped tabs, which project from an edge (24) facing a center of said first one (107) of said heat exchanger plates (101) and is configured to be inserted in one of said depressions (103) provided on said first one (107) of said heat exchanger plates (101).

7. The plate heat exchanger (1) according to claim 1, wherein said two cover plates (21, 22) provide a seat or base (27) for an application of fixing stud bolts and is provided with holes, seats or coupling means for installation of means for fixing said two cover plates (21, 22) one of the at least two hydraulically isolated circuits.

8. The plate heat exchanger (1) according to claim 1, wherein said first one (107) of said heat exchanger plates is equal to at least one of the other heat exchanger plates (101) forming the pack (10).

9. The plate heat exchanger (1) according to claim 1, wherein said heat exchanger plates (101) are all identical or of two different types in order to define hydraulic circuits with different flow resistance.

10. A method of making the plate heat exchanger (1) according to claim 1, comprising the following steps: preparing and assembling said pack (10) of superimposed heat exchanger plates; preparing a steel sheet; performing a stamping step of said steel sheet, wherein one or more of said cover plates (21, 22) are stamped at a time; drilling said steel sheet forming said pair of second holes in pre-determined positions; applying or forming said metal rings (3) on said steel sheet; shearing said steel sheet in at least one shearing step to cut said cover plates (21, 22); and assembling said plate heat exchanger (1), wherein said cover plates (21, 22) are applied to two side portions of the first heat exchanger plate (107) of said pack (10) of heat exchanger plates.

11. The method according to claim 10, further comprising a step of bending said steel sheet to form tabs of said cover plates (21, 22).

12. The method according to claim 10, further comprising a step of coupling said steel sheet with a copper sheet suitable for subsequent braze welding.

13. The method according to claim 10, wherein two or more of said steps are grouped and carried out in a same station.

Description

[0054] The characteristics of the present invention will be better clarified by the following description with reference to the drawings, attached by way of a non-limiting example.

[0055] FIG. 1 shows a three-dimensional view of the completely assembled plate heat exchanger (1), while FIGS. 2 and 3 show a section view and a plan view respectively.

[0056] FIG. 4 shows a three-dimensional view of cover plates (21) to be installed on one side of a heat exchanger plate pack (10), for example on the left.

[0057] FIG. 5 shows a three-dimensional view of cover plates (22) to be installed on one side of a heat exchanger plate pack (10), for example on the right.

[0058] In FIGS. 1 to 5 each of said cover plates (21, 22) has an asymmetrical shape, according to a first possible embodiment. In contrast, a preferred embodiment of said cover plates (21, 22) is schematized in FIG. 6, where said cover plates (21, 22), whether they are on the right or on the left, have a symmetrical, substantially rectangular shape where the shorter sides are made up of semicircles.

[0059] FIG. 7 shows a section view of a cover plate (21, 22) at the level of the hole (231) made in the cover plate (21, 22) itself, where the metal ring (3′) obtained by deformation and/or stamping of the edge (232) of the hole (231) itself can be seen. In this particular embodiment, said metal ring (3′) is a single solid piece with said cover plate (21, 22), thus without the need for welding or mechanical joining in general.

[0060] The plate exchanger (1) comprises in its main parts at least one pack of exchange plates (10) that is a series of superimposed plates (101) in a pack.

[0061] Each of said exchange plates (101) in turn comprises alternating ridges (102) and depressions (103), arranged preferably and substantially in a herringbone pattern or arranged in two intersecting directions.

[0062] Each of said exchange plates (101) is also provided with two pairs of through-holes (104) for the passage of at least two heat-transfer fluids, said holes (104) being made at the level of lowered and raised areas alternately positioned on the two sides of the plates (101), to convey said two fluids into the spaces between the plates following at least two hydraulically isolated circuits.

[0063] Said exchange plates (101) forming said pack (10) are normally made of thin shaped steel sheets.

[0064] Each exchange plate (101) has a substantially rectangular shape, with two longitudinal sides (105) and two transverse sides (106), and where said fluid through-holes (104) are formed near said transverse sides (106), close to the corners.

[0065] Two cover plates (21, 22) are mounted on the first exchange plate (107) of said pack (10), each shaped in correspondence with the transverse side for which it is intended.

[0066] Each of said cover plates (21, 22) has a shape and dimensions substantially corresponding to the side portions of said first exchange plate (107) close to the two transverse sides (106) and comprises a pair of said holes (23, 231) corresponding to said holes (104) in the exchange plates (101).

[0067] In the example of FIG. 6, each of said cover plates (21, 22) has a symmetrical shape, so that they can be mounted either on the right or the left of the pack (10).

[0068] Each of said cover plates (21, 22) is made of steel sheet or in any case of material normally used or in any case suitable for use in plate heat exchangers.

[0069] As can be seen from FIGS. 1, 2 and 3, said cover plates (21, 22) also act as a seat or base (27) for the application of the fixing stud bolts and can also be suitably provided with holes, seats or coupling means in general for the installation of fixing means to the hydraulic circuit, such as fittings or the like.

[0070] At least one hole (231) in one or both of said cover plates (21, 22) may be provided with a metal ring (3, 3′), necessary to create a hermetic seal between said cover plates (21, 22) and said first exchanger plate (107) at the lowered area in which the through-hole (104) for a fluid is made, in order to convey said fluid from the cover plate (21 22) to the internal channels of the exchanger.

[0071] In the embodiment in FIGS. 4 and 5, said metal ring (3) is for example applied at the level of said hole (231) in the cover plate (21, 22) and constrained/coupled by means of spot welding and/or deformation and/or welding and/or mechanical assembly in general. Said ring (3) is therefore a distinct piece from the cover plate (21, 22) and joined to it during the production/assembly step.

[0072] In the specific and preferred but not exclusive embodiment in FIG. 7, said metal ring (3′) is a single piece with respect to the cover plate (21, 22) being obtained by means of deformation and/or stamping of the edge (232) of the hole (231) in the cover plate (21, 22) itself.

[0073] In this case, the edge (232) of said hole (231) in said cover plate (21, 22) is bent towards one side of the cover plate (21, 22) itself, that is, the side intended to be turned towards said first exchanger plate (107), thus forming said metal ring (3′) in a single solid piece with said cover plate (21, 22).

[0074] Said metal ring (3′) is therefore substantially formed by an open cylinder. The embodiment in FIG. 7 shows how said metal ring (3′) can further comprise a flange (31′) suited to ensure a tight seal in the subsequent assembly of each cover plate (21, 22) to the first exchange plate (107) of the pack (10).

[0075] Said flange (31′) is also preferably obtained by deformation/bending.

[0076] Each of said cover plates (21, 22) may also comprise, but not necessarily, shaped tabs (24, 25), protruding from the edge (26) facing the center of said first exchange plate (107), and suited to be inserted in one of said depressions (103) of said first exchange plate (107) itself.

[0077] Therefore, with reference to the preceding description and the attached drawings the following claims are made.