EP2657636A1 - Plate heat exchanger - Google Patents

Abstract

The exchanger has flow channels that are formed for first medium between individual plates (1) joined together to form pair (P) of plates and for second medium between plate pair. Individual plates and plate pair are connected at longitudinal edges (12) and support surfaces running parallel to main flow direction. Individual plate is provided with turbulence-generating profiling formed perpendicular to main flow direction over entire bottom (11) up to contact surfaces (13) and edge channels with cross section variable over longitudinal extension of channels in contact surface region.

Description

The invention relates to a plate heat exchanger with flowed in cocurrent or countercurrent flow of a first and a second medium flow channels, which are formed for the first medium between each pair of plates connected to individual plates and for the second medium between assembled to a plate stack plate pairs, wherein the individual plates and the plate pairs are connected to one another at longitudinal edges and contact surfaces extending parallel to the main flow direction, wherein each individual plate has longitudinally corresponding, diagonally arranged inflow and outflow cross sections for the first medium and transversely adjacent inflow and outflow cross sections for the second medium, wherein the Abströmquerschnitte for the first medium are each offset by half the height of the inflow and outflow of the second medium, wherein the single plate ver with a turbulence generating profiling see is.

Plate heat exchangers of this type are used industrially with plate dimensions of several meters. One field of application here is the use in waste incineration plants, power plants, chemical plants, refineries and / or the like in which the resulting combustion heat of the flue gas is used to heat a second medium.

A plate heat exchanger according to the above type discloses in detail the German patent DE 41 42 177 C2 , In this case, to increase the efficiency of the heat exchanger or alternatively to reduce the dimensions of the required Single plates guide vanes are provided, which distribute the medium entering through the inflow to the full channel width of the flow channel. In order to avoid dead zones in the inlet region, in particular in the mirror symmetry to the longitudinal center next to the inflow cross-section plate region, the guide vanes are provided with extended Abströmschenkeln, which protrude beyond the longitudinal center of the single plate. In addition, the vanes for equalizing the flow within the flow channel in the longitudinal center of the individual plates are arranged closer to the inflow cross section than in the direction of the longitudinal edge of the single plate. The turbulence-generating profiling, which covers the largest possible area of the individual plates, serves the same purpose.

Although this arrangement has been proven in practice, there are nevertheless disadvantages due to flow bypasses arising on the single plate, which allow the heat medium to flow along the profiling without interaction. This concerns in particular the edge regions of the single plate. As a result, the heat output of the plate heat exchanger decreases, so that it must have correspondingly longer individual plates for a required performance.

It is therefore an object of the invention to provide a plate heat exchanger in which the interaction-free flow of heat medium through the single plate is as low as possible and thus increases the heat output at a constant plate dimension.

For technical solution , a plate heat exchanger according to the preamble of the main claim is proposed, in which the turbulence generating profiling is formed perpendicular to the main flow direction over the entire bottom of the individual plates to the contact surfaces, and the individual plates in the region of the contact surfaces edge channels with a variable across its longitudinal extent cross-section exhibit.

Through this over the entire width of the single plate reaching to its side edges profiling a controlled flow pattern is created while avoiding bypasses. In contrast to the prior art, it is thus avoided that the medium flowing over the single plate migrates into profile-free areas and contributes only to a lesser extent to the heat exchange. Overall, in contrast to the prior art, the result is closer to the side edge

Profiling thus improving the heat output of the heat exchanger.

The edge channels according to the invention also lead, by reducing the barrier-free bypasses, to an improved flow pattern, which in turn increases the heat output of the heat exchanger. The edge channels are formed like a labyrinth and are in the area of the contact surfaces, d. H. formed in the edge region of the individual plates, where otherwise the heat medium would seek a barrier-free and thus interaction-free flow path. The variation of the cross-section over the longitudinal extension of the edge channels ensures that the medium flowing through it can not continue to flow straightforward, but suffers a congestion effect at the narrowings of the cross section. Thus, an interaction-free medium flow through the edge channels of the single plate and consequently also a power loss is greatly reduced. This leads to a performance increase of up to 5% over the prior art. This power increase can also be used to reduce the necessary plate length of the heat exchanger, so that the same performance can be achieved with shorter individual plates.

Particularly advantageously, the edge channels are substantially S-shaped, i. formed several s-shaped. This results in a staggered blocking embossing on both sides of each edge channel, which leads to an increased interaction of the heat medium due to the resulting constrictions and extensions. The blocking embossing can be formed on one side or two sides per edge channel, i. it can be one side of a channel or both sides of a channel can be equipped with corresponding imprints.

Advantageously, the cross section of the edge channels is variable by more than 50%. This reduces the barrier-free cross-section for the medium at a constriction by half or more. In addition, a spatially offset flow channel is created in combination with the s-shaped design, which further enhances the interaction between the medium and the heat exchanger.

The Randkanalsausgestaltung invention results in combination with the inventive design of the turbulence generating profiling into the respective edge region of each individual plate the synergistic effect that free flow paths for the medium are basically avoided. The in the Plate heat exchanger inflowing media can thus avoid a pass-like, interaction-free flow path. Neither the edge near the bottom of each individual plate nor in the edge region between two individual plates forming edge channel represent according to the embodiment of the invention in contrast to the prior art such Beipassführung, since the edge channels according to the invention are designed like a labyrinth and the turbulence causing profiling into the edge region is pulled into each individual plate. As a result, with a constant plate size, a performance increase or with the same power a reduced plate size can be achieved. For such a configuration, there is no model in the prior art.

The invention provides that the onflow limbs and the outflow limbs have an angle between 140 ° and 100 °, preferably 135 ° and 112 ° to each other. The shorter the vanes are, the steeper inflow limbs and outflow legs can be arranged to one another. As a result of the combination with an inflow leg oriented substantially parallel to the main flow direction, angling of up to 90 ° is thus also possible, without the risk of blockages of the inflow cross sections due to foreign substance deposits on the guide vanes.

It is recommended that the individual plates within an inlet region formed by embossments, projecting into the flow channel guide vanes, wherein the guide vanes arcuately formed with a substantially parallel to the main flow direction aligned inflow leg and at an angle to the inflow leg aligned Abströmschenkel, wherein the turbulence generating Profiling of the individual plates has pronounced nubs. The nubs can be produced very easily and inexpensively by embossing the individual plates. A uniform pimple field is also ideally suited to increase the performance of the heat exchanger. Due to the turbulent flow of heat transfer is increased and thus improves the efficiency.

In addition, some of the nubs may be formed as spacers for adjacent individual plates. As a result, the predetermined plate spacing over the full channel length and channel width can be ensured even with small distances between adjacent individual plates. Such spacers can also be formed in the region of the guide vanes to the individual plates in the area of the inflow and Keep outflow cross sections at the specified distance from each other. Of course, all nubs can serve as spacers.

In addition, it is proposed that the guide vanes of the inflow cross sections do not protrude beyond the longitudinal center of the individual plates, i. the vanes are formed exclusively in the plate halves assigned to the respective inflow cross sections, the inflow limbs and the outflow limbs of the vanes having substantially equal lengths, and wherein the inflow limbs of the vanes are respectively arranged directly on the transverse edges of the individual plates running essentially perpendicular to the main flow direction. Due to the shorter, steeper to the main flow direction and closer to the edge arranged vanes, the adhesion of the dirt particles is minimized. This reliably prevents clogging of the inflow cross sections, which would otherwise result in expensive cleaning.

Furthermore, it is proposed that the turbulence-generating profiling in the region of the inflow cross-sections project up to the guide vanes and be recessed in the region of the outflow cross-sections. By this profile recess in lying next to the inflow cross-sections plate half creates a negative pressure relative to the gas pressure within the profiled inflow cross-section, whereby an intake of the incoming flue gas is effected in the profile-free area. Thus, a homogeneous distribution of the inflowing medium is effected on the entire plate width, which in turn positively affects the performance of the plate heat exchanger.

The invention Leitschaufelnausgestaltung one hand, and the inventive design of the turbulence generating profiling on the other hand provide in combination the synergistic effect that a homogenization of the incoming media in the plate heat exchanger on the entire plate width, while minimizing the risk of leading to blockages in the worst case Contamination of the vanes. This is in contrast to the prior art according to the aforementioned DE 41 42 177 C2 with the invention deliberately in contrast to the previous embodiment proposed to reduce the guide vanes, in particular with regard to the respective discharge limb. In addition, in deliberate departure from the prior art, the number of vanes has been significantly reduced. The according to the statements in the DE 41 42 177 C2 As a result of these measures, the fear of deterioration in the equalization of media is more surprising

Way did not occur or could be compensated in combination with the inventive design of the turbulence generating profiling. As a result of the embodiment according to the invention, a reduction in the attack caused by the guide blades attack surfaces for dirt particles, foreign substances and / or the like is achieved in a relation to the prior art increased efficiency in terms of media distribution. As a result, the plate heat exchanger according to the invention, in contrast to previously known plate heat exchangers, is less susceptible to soiling or even blockage, as a result of which the operational reliability is increased and / or maintenance intervals can be increased. In this context, it has a particularly positive effect that the outflow legs of the guide vanes according to the invention, in contrast to the prior art, are much steeper and much shorter.

Advantageously, the guide vanes are completely embossed, so that these rest without gaps on the adjacent individual plate. With this configuration, the guide vanes serve completely as a support or as a spacer, so that vibrations within the plate pairs and within the plate stack are reduced and thus the structure of the heat exchanger is more stable overall. Depending on the embodiment, the fully stamped guide vanes may rest on the guide vanes of adjacent individual plates or on the opposite wall of the flow channels.

Fig. 1

eine perspektivische Ansicht eines aus mehreren Einzelplatten gebildeten Plattenstapels, wobei jedoch wegen der besseren Übersicht die Leitschaufeln und die Profilierung nicht dargestellt sind,

Fig. 2a

eine Draufsicht auf eine erfindungsgemäße Einzelplatte mit Leitschaufeln und angedeuteter Profilierung,

Fig. 2b

eine perspektivische Ansicht eines aus mehreren Einzelplatten nach Figur 2a gebildeten Plattenstapels,

Fig. 3

eine vergrößerte Detaildarstellung eines erfindungsgemäßen s-förmigen Randkanals,

Fig. 4 a

eine Schnittdarstellung gemäß Schnitt "A" des s-förmigen Randkanals,

Fig. 4 b

eine Schnittdarstellung gemäß Schnitt "B" des s-förmigen Randkanals

Fig. 4 c

eine Schnittdarstellung gemäß Schnitt "C" des s-förmigen Randkanals.

Further features and advantages of the invention will become apparent from the following description with reference to FIGS. Showing:

Fig. 1

a perspective view of a plate stack formed from a plurality of individual plates, but for reasons of clarity, the guide vanes and the profiling are not shown,

Fig. 2a

a top view of a single plate according to the invention with vanes and indicated profiling,

Fig. 2b

a perspective view of one of several individual plates FIG. 2a formed plate stack,

Fig. 3

an enlarged detail of an inventive S-shaped Edge channel

Fig. 4 a

a sectional view according to section "A" of the S-shaped edge channel,

Fig. 4 b

a sectional view according to section "B" of the S-shaped edge channel

Fig. 4 c

a sectional view according to section "C" of the S-shaped edge channel.

This in FIG. 1 schematically illustrated embodiment of a plate heat exchanger shows in perspective a plate stack S of a plurality of stamped individual plates 1, which are each connected to a pair of plates P. Each individual plate 1 comprises a bottom 11, which lies in a different plane than the longitudinal edges 12. Following and parallel to these longitudinal edges 12, each individual plate 1 is in each case formed with a contact surface 13, which is offset in height relative to the longitudinal edges 12. The offset between the abutment surface 13 and the associated longitudinal edge 12 is twice as large as the offset between the longitudinal edges 12 and the bottom 11. The floor 11 is therefore in height in the middle between the plane of the longitudinal edges 12 and the plane of the contact surfaces 13. Die In the embodiment, somewhat perpendicular to the longitudinal edges 12 of the single plate 1 extending edges lie in the plane of the longitudinal edges 12 and in the plane of the contact surfaces 13. In this way, transverse edges 14a and 14b, in height, ie perpendicular to the surface of the bottom 11 are offset by the same amount as the planes in which on the one hand the longitudinal edges 12 and on the other hand the contact surfaces 13 lie. The FIG. 1 clearly shows that in this case the transverse edges 14a and 14b are diagonally opposite each other.

Two of each in FIG. 1 As a top part illustrated individual plates 1 are shown in the lower illustration in FIG. 1 connected to plate pairs P. In FIG. 1 five complete plate pairs P are shown, wherein on the uppermost plate pair still a single plate 1 is arranged, which is also connected to the spaced top single plate 1 to a pair of plates P.

If the plate pairs P are connected in the region of the contact surfaces 13 to the plate stack S, resulting superimposed channels for the two participating in the heat exchange media. While a medium flows in the flow channels, the are each formed by the plate pairs P, the other medium flows in the flow channels, which result from the joining of the plate pairs P to the plate stack S. The lying in the plane of the longitudinal edges 12 transverse edges 14a of the individual plates 1 in this case form the inflow Z1 and the outflow A1 of the flow channels for the flowing between the plate pairs P medium. The transverse edges 14b of the individual plates 1 running in the plane of the abutment surfaces 13 form the inflow cross sections Z2 and the outflow cross sections A2 for the other medium, which flows between the individual plates 1 of each plate pair P either in the same or in the opposite direction to the first medium. The FIG. 1 , which shows a countercurrent heat exchanger, can be seen that due to the diagonal arrangement of the inlet and outlet openings, the inflow Z1 or Z2 for the one medium next to the outflow sections A2 and A1 for the other medium, each by half Height of a pair of plates P offset.

FIG. 2a shows a single plate 1 according to the invention, the Zuströmquerschnitt Z1 extends over half the width of the single plate 1, from the longitudinal center to the longitudinal edge 12. The single plate has an inlet region E whose length in the main flow direction characterizes the distance which the inflowing medium requires in order to be distributed over the full width of the single plate 1. In the image plane, four guide vanes 2 are arranged to the right next to the longitudinal center of the single plate 1, which each have an inflow leg 21 and a discharge limb 22. The on-stream legs 21 and outflow legs 22 are approximately the same length and enclose an angle of approximately 140 ° to 100 ° between them. In this case, none of the outflow limb 22 projects beyond the longitudinal center of the single plate 1. The on-stream legs 21 are each mounted in the immediate vicinity of the transverse edge 14a. The single plate 1 has over its entire width up to the contact surfaces 13 a turbulence generating profiling 31, 32. This profiling 31, 32 consists of a large number of embossed nubs 31, 32 embossed in the single plate 1, which extend in the region of the inflow cross section Z1 as far as the guide vanes 2 and are recessed in the area to the left of the longitudinal center.

In the area of the contact surfaces 13 are with respect to the image plane to FIG. 2 S-shaped edge channels 15 formed with a size variable over its longitudinal extension cross-section.

FIG. 2b can be seen in a perspective view one of a plurality of individual plates 1 plate stack S formed. The interaction of the individual plates 1 can be taken from this presentation well.

The FIG. 3 shows such an enlarged edge channel 15 shown in plan view. The Figures 4 a, 4 b and 4 c show sectional views of this edge channel 15 at different interfaces A, B and C according to FIG. 3 , It can be seen that the cross section through which the medium can flow is at maximum point A, while the cross section at points B and C is only about 50% or less of the maximum cross section, the cross section at points B and C respectively is narrowed to different sides of the edge channel 15. This results in the constrictions due to impressions 33, which with respect to the image plane after FIG. 3 are formed part-circular, resulting in the total longitudinally s-shaped channel shape.

The invention works in such a way that the heat medium, in this case flue gas, flowing into the single plate 1 through the inflow cross section Z1, meets the on-stream leg 21 of the guide vanes 2, which adjoins the transverse edge 14a directly. From there, the flue gas is passed to the outflow legs 22, which are at an angle of about 140 ° to 100 ° to the on-stream legs 21. Characterized in that the inlet region E in the region of the inflow Z1 has a directly following the vanes 2 profiling 31, 32, while in the mirror-symmetrical left of the longitudinal center region of the inlet plate 1 no profiling is formed above the profiling 31, 32 within the inlet region E from a pressure distribution, which sucks the inflowing flue gas from the guide vanes 2 in the profile-free area. As a result, the flue gas is distributed uniformly over the plate width and ensures a homogeneous heat output over the entire inlet plate 1 of the heat exchanger. Due to the particularly short and steep design of the guide vanes 2, the adhesion of dirt particles to the guide vanes 2 is reduced, so that a blockage of the inflow Z1 is prevented. Overall, thus creating a low maintenance plate heat exchanger, which requires no loss of performance.

According to one embodiment variant, the single plate 1 may have, in addition to the measures described above, edge channels 15, which have indentations 33 for the purpose of labyrinth formation. This flows into the edge area the single plate 1 reaching medium through the edge channels 15 through and strikes the constrictions and extensions of the respective channel cross-sections, which cause a congestion effect and lead to a higher interaction of the medium with the single plate 1. As in FIG. 3 shown, the flue gas enters the S-shaped cut edge channels 15, where it is in the section A (view FIG. 4 a) the entire channel cross-section has available. In the area of section B (view FIG. 4 b) the flue gas must flow through the first bend, in which the cross-section is reduced by half. This creates the aforementioned congestion effect. Behind the curvature, the cross-section then expands again for a short time in order to reach the region C (FIG. FIG. 4c) again to reduce to half, but this time the s-shape of the edge channel 15 following in the region of the opposite channel side wall. Overall, therefore, due to the higher interaction of the heat medium with the individual plates 1 power losses, which occur in the edge region of the single plate 1 according to the prior art by bypasses, which in turn leads to an increase in performance of the heat exchanger. This effect can be further enhanced by the fact that the turbulence generating profiling 31, 32 is formed over the entire width of the individual plates 1 up to the contact surfaces 13. This helps avoid by-passes and thus improves the performance of the heat exchanger.

LIST OF REFERENCE NUMBERS

A

exit area

A1

outflow cross

A2

outflow cross

e

entry area

P

pair of plates

S

plate stack

Z1

inflow cross

Z2

inflow cross

1

Single plate

11

ground

12

longitudinal edge

13

contact surface

14a

cross-border

14b

cross-border

15

edge channel

2

survey

21

Abströmschenkel

22

Anströmschenkel

31

Einzelnoppe

32

Einzelnoppe

33

impressing

Claims (10)

Plate heat exchanger with in DC or countercurrent flowed through by a first and a second medium flow channels, for the first medium between each pair of plates (P) connected individual plates (1) and for the second medium between assembled to a plate stack (S) plate pairs (P ), wherein the individual plates (1) and the plate pairs (P) at parallel to the main flow direction extending longitudinal edges (12) and contact surfaces (13) are interconnected, each individual plate (1) corresponding longitudinally, diagonally arranged inflow and outflow (Z1, Z2, A1, A2) for the first medium and in the transverse direction adjacent to these lying inflow and outflow cross sections (Z1, Z2, A1, A2) for the second medium, wherein the inflow and outflow cross sections (Z1, Z2 , A1, A2) for the first medium in each case by half the height of the inflow or outflow cross sections (Z1, Z2, A1, A2) for the second med ium staggered, wherein the single plate (1) is provided with a turbulence generating profiling (31, 32),
characterized, - That the profiling (31, 32) is formed perpendicular to the main flow direction over the entire bottom (11) to the contact surfaces (13), and - That the individual plates (1) in the region of the contact surfaces (13) edge channels (15) having a variable in size over its longitudinal extension cross-section. Plate heat exchanger according to claim 1, characterized in that the edge channels (15) are formed substantially s-shaped or multiple s-shaped. Plate heat exchanger according to claim 1 or 2, characterized in that the cross section of the edge channels (15) is variable by up to 50% or more. Plate heat exchanger according to one of the preceding claims, characterized in that the individual plates (1) within an inlet region (E) formed by forms, projecting into the flow channel guide vanes (2), wherein the guide vanes (2) arcuate with a substantially parallel to the main flow direction oriented The inflow limbs (21) and an outflow limb (22) aligned at an angle to the inflow limb (21) are formed, wherein the inflow limbs (21) and the outflow limbs (22) form an angle between 140 ° and 100 °, preferably 135 ° and 112 ° to each other exhibit. Plate heat exchanger according to one of the preceding claims, characterized in that the turbulence-generating profiling (31, 32) has pronounced nubs (31, 32). Plate heat exchanger according to claim 5, characterized in that some of the nubs (31, 32) are designed as spacers for adjacent individual plates (1). Plate heat exchanger according to one of the preceding claims 4 to 6, characterized in that the guide vanes (2) of the inflow cross sections (Z1, Z2) do not protrude beyond the longitudinal center of the individual plates (1), wherein the inflow limbs (21) and the outflow limbs (22) in Have substantially equal lengths, and wherein the guide vanes (2) at substantially the same distance to the associated transverse edge (14a, 14b) of the respective single plate (1) are arranged. Plate heat exchanger according to one of the preceding claims 4 to 8, characterized in that the turbulence-generating profiling (31, 32) in the inlet region (E) of the inflow cross sections (Z1, Z2) up to the guide vanes (2) protrudes and in mirror symmetry to the longitudinal center of the individual plates (1) adjacent area of the outflow cross sections (A1, A2) is recessed. Plate heat exchanger according to one of the preceding claims 4 to 8, characterized in that the guide vanes (2) are completely stamped through, so that they rest without gaps on the adjacent individual plate (1). Plate heat exchanger according to claim 9, characterized in that the guide vanes (2) serve as spacers of the support.

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