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Title:
STACKING PLATE FOR A STACKED PLATE HEAT EXCHANGER AND A STACKED PLATE HEAT EXCHANGER
Document Type and Number:
WIPO Patent Application WO/2018/073180
Kind Code:
A1
Abstract:
The stacking plate comprises : - a substantially flat base (2a) extending along a principal plane in which first passage openings (7) and second passage openings (8) are provided for the passage of a first medium and a second medium respectively, and - a raised edge (2b) projecting beyond the perimeter of the said substantially flat base (2a) surrounding it continuously. First portions (2bl) and second portions (2b2) of the raised edge (2b) project beyond the perimeter of the base (2a) according to a first lateral angle (α) and a second lateral angle (μ) which are different from each other. The interchanger comprises a plurality of stacking plates (1) according to the invention, which are stacked and attached one above the other alternately.

Inventors:
DE LA FUENTE ROMERO JOSÉ ANTONIO (ES)
TOMAS HERRERO EVA (ES)
FERNANDEZ MARTINEZ ROBERTO (ES)
CONTE OLIVEROS TERESA (ES)
Application Number:
PCT/EP2017/076365
Publication Date:
April 26, 2018
Filing Date:
October 16, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
VALEO TERMICO SA (ES)
International Classes:
F28D9/00
Foreign References:
US20130126137A12013-05-23
DE102010040321A12012-04-19
US20110024095A12011-02-03
US20150096727A12015-04-09
Attorney, Agent or Firm:
METZ, Gaëlle (FR)
Download PDF:
Claims:
CLAIMS

1. - Stacking plate (1, la, lb) for a stacked plate heat exchanger, comprising : a substantially flat base (2a) extending along a principal plane in which first passage openings (7) and second passage openings (8) are provided for the passage of a first medium and a second medium respectively, and

- a raised edge (2b) proj ecting beyond the perimeter of the said substantially flat base (2a) surrounding it continuously, characterized in that first portions (2bl) and second portions (2b2 ) of the said raised edge (2b) proj ect beyond the perimeter of the substantially flat base (2a) in accordance with a first lateral angle ( ) and a second lateral angle (μ) with respect to the said principal plane respectively, in which the said first lateral angle (a) and the second ( μ) are different from each other . 2. - Stacking plate according to Claim 1 , in which the said first portions (2bl) proj ect from straight segments of the perimeter of the substantially flat base (2a) while the said second portions (2b2 ) project from curved segments thereof .

3. - Stacking plate according to Claim 2 , in which the first lateral angle (a) is smaller than the second lateral angle (μ) . 4. - Stacking plate according to Claim 3, in which the first lateral angle (a) has a value of between 8° and 10.5° while the second lateral angle has a value of between 11° and 14°.

5. - Stacking plate according to Claim 2, 3 or 4 , in which the said curved segments form rounded arrises of the substantially flat base (2a) and are interconnected by the said straight segments .

6. - Stacking plate according to Claim 5 , in which the substantially flat base (2a) is of rectangular shape, including four of the said rounded arrises and four of the said straight segments which interconnect each pair of the said rounded arrises .

7. - Stacked plate heat exchanger comprising a plurality of stacking plates (1) according to any one of the preceding claims , including :

- first stacking plates (la) in which the first passage openings (7) are located on the substantially flat base (2a) , while the second passage openings (8) are located on raised annular formations ; and second stacking plates (lb) in which the second passage openings (8) are located on the substantially flat base (2a) , while the first passage openings (7) are located on raised annular formations ; in which the said first stacking plates ( la) and second stacking plates ( lb) are stacked and fixed one above the other alternately, with at least part of their raised edges (2b) nested together through pressure .

Description:
DESCRIPTION

STACKING PLATE FOR A STACKED PLATE HEAT EXCHANGER AND A STACKED PLATE HEAT EXCHANGER

Sector of the art

In a first aspect this invention relates to a stacking plate for a stacked plate heat exchanger configured in such a way that when stacked and connected to another stacking plate interference problems between them are minimized or eliminated .

A second aspect of this invention relates to a stacked plate heat exchanger comprising a plurality of stacking plates according to the first aspect of the invention .

The invention applies especially to heat exchangers (heating or cooling) in motor vehicles , in particular in TOC (Transmission Oil Cooler) and EOC (Engine Oil Cooler) applications .

Prior art The present configuration of oil coolers available on the market corresponds to that of a metal heat exchanger generally made of stainless steel or aluminium . Most of the components of an oil cooler are metal and are assembled by mechanical means and then oined by welding or brazing to ensure the appropriate level of leakage required for the application .

The main function of the oil cooler is to exchange heat between two fluids , the coolant and the oil . In addition to this it must satisfy other functions such as maintaining a low fluid pressure drop, withstanding the working conditions of the fluid, withstanding environmental conditions , providing a connection to oil and coolant circuits , etc . Market requirements have been increasing in terms of needing more efficient and compact coolers which must be capable of working under more exacting conditions ( for example a greater oil pressure and higher temperature) .

In general an oil cooler comprises a set of plates stacked alternately to allow circulation and prevent contact between the fluids , sealing off both circuits , the coolant circulation and the oil circulation . In their manufacture, once the plates have been stacked a vertical force is applied to compact the device and compensate for the lack of actual contact . The circuits comprising the spaces between the plates have to be completely sealed both within the cooler, that is to say the areas surrounding the passage openings defined in the plates , and laterally, that is to say around the outer perimeter of the plates . In the lateral area, that is to say on the outside perimeter, the manner of resolving this problem is by means of raised edges which project beyond the perimeter of a substantially flat base of the plate with a particular inclination so as to close and join together the edges of each plate with those of the plate onto which it is stacked by means of pressure . Thus the plate has a combination of longitudinal dimensions , height dimensions ( that is to say the dimensions of its raised edges) and the angle of its raised edges , which allow the whole to be adjusted . As a consequence , as the surfaces of the plates are brought into contact in this way, they can be welded together .

Obviously the design and manufacture of the cooler components require a range of tolerances in their various dimensions . On the other hand the distances or spaces between the components must nevertheless lie within a small safety zone which allows the components to be welded together . Thus the design of such components , especially that of the stacking plates , must satisfy a compromise between the said range of dimensional tolerances and the said distances or spaces .

Although this problem is quite easy to solve at raised edges proj ecting from the straight segments of the perimeter of the substantially flat bases of the plates , there is greater difficulty at the raised edges proj ecting from their curved segments , because interference or inadequate space in those areas have adverse consequences during assembly. Furthermore, in the curved areas formed by such raised edges of curved segments , deformation as they nest with the edges of the plate onto which they are stacked is not uniform, because they are highly rigid . Experience shows that friction in curved areas has an adverse effect . Also these areas are marked because of the friction when they are stacked together . This friction during assembly and compression of the set gives rise to deformation and as a consequence the deformation occurs in the less rigid areas . Furthermore this deformation is apparent in actual parts which include visible spaces between the stacked plates , especially in areas corresponding to the raised edges of the shorter straight segments of the stacking plates .

Thus this deformation gives rise to displacement of the straight areas , giving rise to spaces between the plates and as a consequence leaks of fluid (coolant or oil ) to the exterior , which is a technical problem requiring a solution . Patent US7717164B2 describes a stacked plate heat exchanger formed by stacking plates having the characteristics of the precharacteri z ing clause of Claim 1 of this invention . Other patent documents representative of the state of the art and describing stacked plate heat exchangers are the documents JP2006010192A, DE19828029A1 and EP1452816B1.

In none of the cited documents is there provided a solution to the technical problem mentioned above , that is to say the production of fluid leaks caused by displacements due to deformation between the stacked plates .

It would therefore appear necessary to offer an alternative to the state of the art covering the shortcomings found in it , by providing a solution to the technical problem mentioned above .

Explanation of the invention With this obj ect a first aspect of this invention relates to a stacking plate for a stacked plate heat exchanger comprising, in a manner which is in itself known : - a substantially flat base extending along a principal plane, in which first passage openings and second passage openings are located for the passage of a first medium and a second medium respectively, and - a raised edge proj ecting beyond the perimeter of the said substantially flat base , surrounding it in a continuous manner .

Unlike the stacking plates known in the state of the art , in the proposal for the first aspect of this invention first and second portions of the mentioned raised border are characteristically proj ected beyond the perimeter of the substantially flat base in accordance with first and second lateral angles with respect to the said principal plane respectively, in which the said first and second lateral angles are different from each other .

In this way by suitably selecting such first and second angles according to the application or final design of the exchanger for which the stacking plate is intended it is possible to solve the technical problem indicated above , as it brings about suitable contact between the different portions of the raised edges of the separate plates stacked and nested together, optimizing interference between them . According to one embodiment the said first portions proj ect from straight segments of the perimeter of the substantially flat base while the second portions proj ect from curved segments thereof . According to a preferred embodiment the first lateral angle is smaller than the second lateral angle .

In one embodiment in which the first portions proj ect from straight segments of the base perimeter and the second portions proj ect from curved segments thereof , and the first lateral angle is smaller than the second, interference in curved areas is minimized when stacking plates designed according to the first aspect of the invention are stacked and nested, these said curved areas being those where suitable contact between the faces of the raised edges is most difficult .

That is to say that , for the embodiment mentioned, through the first aspect of this invention a design of stacking plate with different lateral angles at the raised edges of the straight segments of the perimeter of the base of the plate in comparison with those of the curved segments is provided in order to compensate for the fact that they behave differently when they are nested together . This solution makes it possible to provide assembly conditions that differ between the different areas , that is to say between the raised edges of the different segments of the perimeter of the base of the stacking plates , in order to solve or minimize problems of interference between them .

Thanks to this difference in the lateral angles , when the stacking plates are stacked together during assembly of the exchanger the raised edges proj ecting from the straight segments of the perimeter of the bases of the stacked plates are in contact with each other, but the raised edges corresponding to the curved segments are not as there is a gap between them in order to avoid interference .

Subsequently, during the assembly process , when a compression force is applied in the stacking direction, the whole becomes compacted and the raised edges corresponding to the straight segments deform slightly, while at the same time those corresponding to the curved segments come into contact with each other and are vertically compressed until they achieve adequate contact , thus avoiding the undesired deformation at the raised edges corresponding to the straight segments which occurred in the state of the art due to friction between the raised edges of the curved segments . According to one implementation of the said preferred embodiment the first lateral angle has a value of between 8° and 10.5° while the second lateral angle has a value of between 11° and 14°. Obviously angles having other values which differ from those indicated are also covered by this invention . In one embodiment the curved segments mentioned form rounded arrises of the substantially flat base and are interconnected by the straight segments mentioned . In one implementation of the said embodiment the substantially flat base is of rectangular shape, including four of the said rounded arrises and four of the said straight segments which are each interconnected by rounded arrises .

In other embodiments the stacking plate according to the first aspect of the invention comprises more than two portions of the raised edge mentioned which proj ect beyond the perimeter of the substantially flat base according to more than two lateral angles with respect to the principal plane respectively, in which the more than two lateral angles are different from each other .

A second aspect of this invention relates to a stacked plate heat exchanger comprising a plurality of stacking plates according to the first aspect of the invention, including : first stacking plates in which the first passage openings are located in the substantially flat base , while the second passage openings are located in raised annular formations ; and

- second stacking plates in which the second passage openings are located in the substantially flat base, while the first passage openings are located in raised annular formations .

In the heat exchanger proposed in the second aspect of this invention the first and second stacking plates are stacked and fixed one above the other alternately, with at least part of their raised edges nested together by means of pressure . Brief description of the drawings

The above and other advantages and characteristics will be more fully understood from the following detailed description of embodiments with reference to the appended drawings , which are to be considered illustrative and non- limiting , in which : Figure 1 is a perspective view illustrating a plurality of stacking plates according to one embodiment of the first aspect of the invention, stacked together with the exception of one, the uppermost one, which is located in a position prior to being nested and stacked on the one located immediately below .

Figure 2a is a view in elevation of the stacking plate provided by the first aspect of the invention for an embodiment corresponding to the uppermost plate in Figure 1.

Figure 2b is a plan view of the stacking plate provided for the first aspect of the invention, for the same embodiment as in Figure 2a.

Figure 3a is a partial view in transverse cross section of the stacking plate in Figure 2b along a section plane indicated by the line G-G, which includes the raised edge proj ecting from a curved segment of the perimeter of the base of the plate .

Figure 3b is a partial view in transverse cross section of the stacking plate in Figure 2b along a section plane indicated by the line E-E, which includes the raised edge proj ecting from the straight segment of the perimeter of the base of the plate . Figure 4a is a view in elevation showing portions of three stacking plates according to one embodiment of the first aspect of this invention, stacked together in an initial situation during assembly, including the raised edges which proj ect from straight segments of the perimeter of their base .

Figure 4b is a view in elevation showing other portions of the three stacking plates according to the same embodiment as in Figure 4a, stacked together in the same initial assembly situation, where the portions in this case include the raised edges proj ecting from curved segments of the perimeter of the base of the plates .

Detailed description of embodiments

As will be seen in the appended figures , especially Figures 1, 2a and 2b, stacking plate 1, la, lb for a stacked plate heat exchanger according to the first aspect of this invention comprises : a substantially flat base 2a extending along a principal plane, in which first passage openings 7 and second passage openings 8 are provided for the passage of a first medium and a second medium respectively, and

- a raised edge 2b proj ecting beyond the perimeter of the said substantially flat base 2a, surrounding it continuously.

Figure 1 likewise illustrates part of the stacked plate heat exchanger according to the second aspect of this invention, in particular a plurality of stacking plates 1 which include : first stacking plates la in which first passage openings 7 are located in the substantially flat base 2a, while second passage openings 8 are provided in raised annular formations ; and

- second stacking plates lb in which the second passage openings 8 are located in the substantially flat base 2a, while first passage openings 7 are located in raised annular formations .

First stacking plate la and second stacking plate lb are stacked and attached one above the other alternately, with their raised edges 2b stacked together through pressure .

The remaining elements of the heat exchanger according to the second aspect of this invention (cooling fluid inlet/outlet pipes , bottom support or base , upper plate or cover, etc . ) have not been illustrated as they are considered to be of a conventional type . As will be seen in Figures 1 and 2b, the raised edge includes first portions 2bl proj ecting beyond curved segments of the perimeter of substantially flat base 2a, in particular from four curved segments corresponding to four rounded arrises of the said perimeter, together with second portions 2b2 proj ecting beyond straight segments of the said perimeter of substantially flat base 2a, in particular from four flat segments which are each interconnected by the said four rounded arrises .

Figure 3b shows how first portions 2bl proj ect beyond the curved segments of the perimeter of substantially flat base 2a according to a first lateral angle a with respect to the said principal plane, while Figure 3a shows how second portions 2b2 proj ect beyond the curved segments of the said perimeter according to a second lateral angle μ , the first lateral angle and the second μ being different from each other, in particular the first a being smaller than the second μ , for the embodiment illustrated .

Figures 4a and 4b show the effect achieved through the difference in lateral angles a and μ , as already- explained in a previous section .

In particular said Figures 4a and 4b illustrate an initial assembly position in which the three stacking plates according to the invention are stacked together but no vertical compression force has yet been applied (or, if it has been applied, it is very small ) , in such a way that while raised edges 2bl proj ecting from the straight segments of the perimeter of bases 2a of the stacked plates are in contact with each other, as will be seen in Figure 4a, raised edges 2b2 proj ecting from the curved segments of the said perimeter are not , there being a space between them in order to prevent interferences , as will be seen in Figure 4b.

As explained previously, subsequently in a subsequent assembly stage (not illustrated) , when a compression force is applied in the stacking direction the whole becomes compacted and raised edges 2bl deform slightly and at the same time raised edges 2b2 come into contact with each other and are compressed vertically until they make suitable contact , thus avoiding undesired deformation of raised edges 2bl which occurred in the state of the art due to friction between raised edges 2b2.

The present inventors have performed experiments with stacking plates constructed, stacked and assembled together, and have achieved as a result that no spaces between the plates or any visible deformations between the raised edges thereof are produced, neither before or after they are welded together by brazing . Likewise the present inventors have carried out digital computer simulations of assembled sets of rectangular stacking plates designed according to a first aspect of the invention and conventional rectangular stacking plates , obtaining as a result values for Von Mises stress levels which are approximately 25% smaller in the set of plates according to this invention than those in conventional stacks , in the areas experiencing greatest stress , that is to say in the areas corresponding to the raised edges proj ecting from the shortest straight segments of the perimeters of the bases of the stacking plates .

A person skilled in the art could introduce changes and modifications in the embodiments described without going beyond the scope of the invention as defined in the appended claims .