The invention relates to a heat exchanger, comprising at least a plurality of rows of media guiding ducts for passing a media flow along their inner, mutually facing boundary walls and a plurality of rows of fluid ducts for passing fluid to be temperature-controlled, wherein said fluid ducts are at least in part located in pairs opposite from each other and accommodate at least one row of media guiding ducts between each other, at least one of the free rectangular end faces of which without coating form a media inlet, wherein at least some of the fluid ducts have a deflector device, which routes contaminant particles entrained in the medium at least in part away from the fluid ducts in the direction of the media ducts, wherein said deflector device is formed by a strip-shaped flow profile part, which is arranged on the free end face of an assignable fluid duct and closes the latter outwards towards the environment and projects beyond the latter, and wherein said deflector device has a guide part and a plug-in part, which is in one piece connected to the guide part and is inserted into the respective assignable fluid duct.
Heat exchangers, which routinely operate as liquid-air heat exchangers, are state of the art, see for instance DE 10 2010 046 913 A1. To achieve the cooling capacities required for the individual applications, air-liquid coolers are usually operated as active coolers having cooling fans that generate the air flow required for an effective heat exchange in the air ducts. To increase the effective heat transfer surface, heat exchangers of this type have cooling fins in their air guiding ducts, preferably in the form of meandering fins made of thin aluminum sheet. When heat exchangers of this type are operated in dust-laden air, particles accumulate on the surfaces facing the air flow. The progressive accumulation of particles results in the air path becoming clogged and in an increased pressure drop, which can no longer be compensated by the blower, causing the air volume, flowing through the air ducts, and consequently the heat transfer to decrease drastically.
DE 31 40 408 A1 also describes a heat exchanger, in particular for use in an internal combustion engine, which is formed in flat tube design, fin design or plate design and through which air flows as a cooling medium, wherein in front of the cooling air inlet end of the heat exchanger a replacement mockup, having the same lattice structure, as the heat exchanger is arranged. Plug-in parts are used to close the associated media ducts at the end, wherein said plug-in parts are flush with the rectangularly arranged end faces of the respective media duct, and the replacement mockup with its individual flow profile parts is placed in front of the plug-in parts and, for the purpose of routing the air flow, its parabolically shaped guide parts project into the free opening cross section of the air-conveying fluid duct each arranged adjacent to a media duct.
DE 31 09 955 A1 describes a generic plate heat exchanger having intermediate layers arranged between the plates in a zigzag shape and each arranged alternating on two edges, opposite to each other, of the plates and flush with the plates except for the protruding parts. The plates delimit flow ducts for the cross-guiding of heat exchange media, one of which is gaseous, such as air. To reduce the accumulation of dirt on the incident-flow end, exposed to the gaseous heat exchange medium, of the heat exchanger, this end is provided with a plastic coating, having a uniformly smooth surface, which, on the part of the surface, immediately succeeding the incident-flow end, ends at an inclination preventing flow separation. This plastic coating evens out the roughnesses resulting from the manufacture of the parts of the heat exchanger.
DE 39 26 283 A1 describes another generic recuperative hollow-chamber plate heat exchanger with aerodynamic incident-flow and outgoing-flow surfaces that are part of flow profiles, plugged-in as separator webs in the end faces of adjacent hollow-chamber plates of the known heat exchanger. The use of hollow-chamber plates in the known solution replaces previous forms of individual sheet metal plates, which are canted against each other, and can vibrate more or less permanently. The flow profile parts referred to, which with their guide parts protrude from the hollow chamber plates and apart from that with their plug-in parts are, connected in one piece to the guide parts, are permanently plugged-in into the hollow chamber plates, also achieve a permanent calibration, wherein the incident-flow surfaces for the flow profile parts are fluidically designed such that the pressure loss of the medium on entering and exiting the heat exchanger is only slight.
In view of this state of the art, the invention addresses the problem of providing a heat exchanger, which, in comparison, is characterized by a more favorable operating behavior.
According to the characterizing part of patent claim 1, this problem is solved by a heat exchanger of the type mentioned at the outset in that at the transition between the guide part and the plug-in part two mutually opposite steps are formed, which allow the flow profile part to sit on the adjacent end faces of a fluid duct without spacing, and in that the flow profile part does not project at any point into a free opening cross-section, which is defined by the imaginary extension of the inner, mutually facing boundary walls of a media duct and by the media inlet. In this way, the free incident flow of the media flow, which may be loaded with contaminants, such as dust-laden air, is not impeded by any flow profile parts, because their media conveying guide parts leave the propagated incident flow space completely empty, which is prespecified by the imaginary duct extension of the respective media duct. In particular, turbulence, that could impede the media (air) entrance, is prevented in this way, and improved dirt rejection and dirt accumulation by the guide parts or at the guide parts with their guide surfaces are achieved. In this respect, the solution according to the invention also manages entirely without a coating in the context of flow routing, which contributes to reducing costs, prevents unnecessary vibrations during operation and does not impair free flow routing.
Because of the integral design of the flow profile parts with their plug-in and guide parts, they can be manufactured cost-effectively in a continuous casting process or an extrusion molding process and the fluid ducts are braced, in particular at their free end faces, which also increases the overall stability of the heat exchanger. Another factor in aid thereof is at the transition between the guide part and the plug-in part of a flow profile part two mutually opposite steps formed, with a matching widening of the diameter towards the guide part, wherein the flow profile part is seated via the steps on the adjacent end faces of a fluid duct without spacing, and therefore in a sealing manner. In this respect, sealing problems in this area are reliably prevented and the flow profile part can be supported against the direction of flow of the media (air) at the end faces of the reference walls of the respective fluid duct across the entire surface(s).
The deflector device according to the invention can be used to route the contaminant particles entrained in the medium, such as air, away from the fluid ducts in the direction of the media guiding ducts. The guide function of the deflector, which influences the flow of the media, fosters the removal of contaminant particles via the media ducts. Compared to otherwise known deflector-free and therefore flat incident-flow surfaces facing the media flow, this impedes the accumulation of contamination particles to achieve an increased operational reliability for dust-laden media such as air, while reducing the risk of blockage. When particles are referred to as contaminants, this includes fibers of any kind, also in the form of plant fibers and the like as they occur when material is chopped and can easily occur in agricultural applications of the heat exchanger with assigned working machines.
The fluid channels can also contain liquids to be cooled or temperature-controlled, such as water-glycol mixtures, lubricants and fuels including transformer oils and HFC liquids, etc. In principle, however, it is also possible to heat such liquids in the fluid ducts by means of gaseous, liquid or paste-like media in the media ducts as part of temperature control. Also, hot gases, such as hot process gases, routed in the media ducts can be cooled by cooling fluids in the fluid ducts. The assigned media guiding ducts and fluid ducts can separate gas/gas; gas/liquid; liquid/gas; and liquid/liquid from each other and permit a temperature exchange in the direction of assimilation of medium and fluid. The respective medium mentioned can also consist of gas mixtures and mixtures with liquids. Liquids can also have gaseous components. Furthermore, the use of paste-like media is possible in context of the heat exchanger arrangement.
The deflector device is formed by at least one flow profile part, which is arranged at the free end face of the assignable fluid duct and closes off the latter towards the outside from the surroundings and projects above thereof. Advantageously, the respective flow profile part for the assigned fluid duct can form a closing part sealing the latter's front end, preferably in the form of the insert part or plug-in part.
The respective flow profile part can advantageously have at least one guide surface, which routes the media flow in the direction of the media inlet to at least one adjacent media duct.
The arrangement can advantageously be made such that the guide surface of the respective flow profile part is formed to be flat, curved or stepped in sections. The geometry can advantageously be adapted to the conditions of the different applications of the heat exchanger, for example to the nature of the dirt particles burdening the media flow, to the dimension of the ducts and the like.
With particular advantage, two guide surfaces of a flow profile part can be formed to extend towards each other on the end facing away from the assignable fluid duct. The thereby resulting reduction in the cross-sectional area in the front pressure area of the flow section parts, facing the media flow, results in a low flow resistance of the deflector device.
In particularly advantageous exemplary embodiments, two guide surfaces of a flow profile part are formed at an acute angle to each other. As a result, a particularly effective outgoing-flow of the dirt particles can be achieved with a particularly low flow resistance generated by the pointed shape.
In preferred exemplary embodiments, the fluid ducts each open out on both sides into a collecting space, wherein the media guiding ducts are delimited by fins, which extend in a row arrangement at least partially between the adjacent fluid ducts. The flow guiding bodies extend continuously in the form of strips from one collecting space to the next. The arrangement can advantageously be made such that, at least during operation, the fluid ducts extend horizontally between the collecting chambers and that the fins, in particular in a zigzag arrangement, delimit the media ducts. The vertically extending collecting chambers can be hollow boxes forming the struts of the stand of a rectangular structure in which the incident-flow surface is spanned between the collecting chambers. However, the hollow box formed in this way does not necessarily have a square cross-section. The deflector device can be an integral part of the heat exchanger; however, it is also possible to place the deflector device in front of the media inlet of the heat exchanger as an independent add-on part conceived similar to a front mounting frame.
The object of the invention is also a deflector device, which is provided in particular for a heat exchanger according to one of patent claims 1 to 7 and which has the features of patent claim 8.
The invention is explained in detail below with reference to exemplary embodiments shown in the drawing. In the Figures:
The exemplary embodiment of the heat exchanger, shown in
In the usual manner for such heat exchangers and as shown in the aforementioned document DE 10 2010 046 913 A1, superposed rows of media ducts 12 (see
As shown in
Just as the media guide ducts 12 have zigzag-shaped or meandering fins for improved flow guiding and heat exchange, there can also be flow guides of comparable construction in the fluid ducts 14 for flow guiding of the fluid, viewed in the direction of the incident flow. It is also possible to form the free end face of the deflector device 20 as a calotte when viewed in cross-section. Particularly preferably, the free end face of the fluid duct 14 can be closed by an adapter mount, which allows different types of profiles to be used interchangeably on the heat exchanger 1, wherein it is also possible depending on the specifications to exchange differently formed profile cross-sections using the adapter (not shown).
As
Number | Date | Country | Kind |
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10 2019 000 922.3 | Feb 2019 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/079421 | 10/28/2019 | WO | 00 |