Plate heat exchanger

Abstract

A plate heat exchanger has flow channels through which a first flow and a second flow pass in concurrent or countercurrent flow. The flow channels are formed for the first medium between individual plates (1) joined together to form in each case a pair (P) of plates, and for the second medium between pairs (P) of plates joined together to form a stack (S) of plates, wherein the individual plates (1) within an inlet region (E) have guide blades (2) which are formed by stamped embossments and protrude into the flow channel, wherein the guide blades (2) are formed in an arch-shaped manner with an inflow leg (21) aligned substantially parallel to the main flow direction and an outflow leg (22) aligned at an angle to the inflow leg (21).

Claims

1. A plate heat exchanger comprising flow channels through which a first and a second flow flows in concurrent or countercurrent flow, which flow channels are formed for a first medium between individual plates (1) joined together to form pairs (P) of plates, respectively, and for a second medium between the pairs (P) of plates joined together to form a stack (S) of plates, wherein the individual plates (1) and the pairs (P) of plates are connected to each other at longitudinal edges (12) and contact surfaces (13) running parallel to a main flow direction, wherein the stack of plates comprises inflow and outflow cross-sections (Z1, Z2, A1, A2), arranged diagonally and corresponding in a longitudinal direction, for the first medium and inflow and outflow cross-sections (Z1, Z2, A1, A2), adjacent thereto in a transverse direction, for the second medium, wherein the inflow and outflow cross-sections (Z1, Z2, A1, A2) for the first medium are in each case offset by half the height of the inflow and outflow cross-sections (Z1, Z2, A1, A2) for the second medium, wherein the individual plate (1) is provided with a profiling (31, 32) that generates turbulences, wherein the profiling (31, 32) is formed perpendicular to the main flow direction over the entire bottom (11) up to the contact surfaces (13), and in a region of the contact surfaces (13), the individual plates (1) are shaped to form edge channels (15) that are arranged between the flow channels and the longitudinal edges (12), respectively, the edge channels delimited in a direction parallel to a stacking direction of the individual plates by opposed upper and lower boundary walls extending in the longitudinal direction, wherein the opposed upper and lower boundary walls of each edge channel each are shaped to provide the respective edge channel with at least two blocking embossments staggered relative to each other over a longitudinal extension of the edge channels, wherein a first one of the blocking embossments is located on a first side of the edge channel facing the flow channels and extends into the interior of the edge channel in a direction toward the longitudinal edge, and wherein a second one of the blocking embossments is located on a second side of the edge channel, opposite the first side and facing the longitudinal edge, and extends into the interior of the edge channel in a direction toward the first side of the edge channel, wherein the blocking embossments each consist of a first embossment member and a second embossment member, wherein the first embossment member is provided by the upper boundary wall and the second embossment member is provided by the lower boundary wall, wherein, viewed in a cross-sectional view, the blocking embossments each extend across the full height of the edge channel and over at least 50% of the width of the edge channel measured from the first side to the second side, wherein the blocking embossments each are shaped as a circle segment and a sagitta of the circle segment equals half of said width of the edge channel or is greater than half of said width of the edge channel, wherein the at least two staggered blocking embossments generate in the edge channels a cross-sectional area having a cross-sectional size that varies over said longitudinal extension, respectively.

2. The plate heat exchanger according to claim 1, wherein the edge channels (15) are formed to be S-shaped or multiple times S-shaped.

3. The plate heat exchanger according to claim 1, wherein the individual plates (1) within an inlet region (E) comprise guide blades (2) formed by stamped embossments protruding into the flow channel, wherein the guide blades (2) are formed in an arch shape with an inflow leg (21) aligned substantially parallel to the main flow direction and an outflow leg (22) aligned at an angle to the inflow leg (21), wherein the inflow legs (21) and the outflow legs (22) are arranged at an angle between 140 and 100 relative to each other.

4. The plate heat exchanger according to claim 3, wherein the inflow legs (21) and the outflow legs (22) are arranged at an angle between 135 and 112 relative to each other.

5. The plate heat exchanger according to claim 3, wherein the guide blades (2) of the inflow cross-sections (Z1, Z2) do not protrude beyond a longitudinal center of the individual plates (1), wherein the inflow legs (21) and the outflow legs (22) have identical lengths, and wherein the guide blades (2) are arranged at the same distance from the associated transverse edge (14a, 14b) of the respective individual plate (1).

6. The plate heat exchanger according to claim 3, wherein the inlet region is divided relative to a longitudinal center of the individual plates into a first region and a second region, wherein the first and second regions each have a peripheral contour and the peripheral contours are mirror-symmetrical to each other relative to the longitudinal center of the individual plates and wherein the guide blades are arranged only in the first region and not in the second region, wherein the profiling (31, 32) protrudes in the first region up to the guide blades (2) and the second region is free of the profiling.

7. The plate heat exchanger according to claim 3, wherein the guide blades (2) are completely stamped through so that the guide blades (2) rest without any gap against the adjacent individual plate (1).

8. The plate heat exchanger according to claim 7, wherein the guide blades (2) as spacers serve for supporting.

9. The plate heat exchanger according to claim 1, wherein the profiling (31, 32) has stamped knobs (31, 32).

10. The plate heat exchanger according to claim 9, wherein some of the stamped knobs (31, 32) are formed as spacers for adjacent individual plates (1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention arise from the following description by means of the figures.

(2) FIG. 1 shows a perspective view of a plate stack formed from a plurality of individual plates, wherein for a better overview, the guide blades and the profiling are not illustrated.

(3) FIG. 2a shows a top view of an individual plate with guide blades and indicated profiling.

(4) FIG. 2b shows a perspective view of a plate stack formed according to FIG. 2a from a plurality of individual plates.

(5) FIG. 3 shows an enlarged detailed illustration of an S-shaped edge channel.

(6) FIG. 4a shows a sectional view according to section A of the S-shaped edge channel.

(7) FIG. 4b shows a sectional view according to section B of the S-shaped edge channel.

(8) FIG. 4c shows a sectional view according to section C of the S-shaped edge channel.

DESCRIPTION OF PREFERRED EMBODIMENTS

(9) The exemplary embodiment of a plate heat exchanger schematically illustrated in FIG. 1 shows perspectively a plate stack S from a plurality of individual plates 1 which are in each case connected to each other so as to form a pair P of plates. Each individual plate 1 comprises a bottom 11 which lies in a different plane than the longitudinal edges 12. Subsequent and parallel to these longitudinal edges 12, each individual plate 1 is formed with a contact surface 13 which is offset in height with respect to the longitudinal edges 12. The offset between the contact surface 13 and the associated longitudinal edge 12 is twice as large as the offset between the longitudinal edges 12 and the bottom 11. Accordingly, the bottom 11 is positioned at the middle of the height between the plane of the longitudinal edges 12 and the plane of the contact surfaces 13. In the exemplary embodiment, the edges running transverse to the longitudinal edges 12 of the individual plate 1 lie approximately half in the plane of the longitudinal edges 12 or in the plane of the contact surfaces 13, respectively. In this manner, the transverse edges 14a and 14b are created which are offset relative to each other in height, i.e., perpendicular to the surface of the bottom 11, by the same amount as the planes in which the longitudinal edges 12 lie, on the one hand, and the contact surfaces 13, on the other. FIG. 1 clearly shows that here, the transverse edges 14a and 14b oppose each other diagonally.

(10) In each case two of the individual plates 1 illustrated in FIG. 1 as the uppermost part are connected according to the bottom illustration in FIG. 1 so as to form pairs P of plates. FIG. 1 exemplary illustrates five complete pairs P of plates, wherein on top of the uppermost pair of plates, an additional individual plate 1 is arranged which is also connected to the uppermost individual plate 1 shown spaced apart so as to form a pair P of plates.

(11) When the pairs P of plates are connected in the region of the contact surfaces 13 so as to form a plate stack S, this results in channels arranged on top of each other for the two media involved in the heat exchange. While the one medium flows in the flow channels which are formed in each case by the pairs P of plates, the other medium flows in the flow channels which are formed by joining the pairs P of plates together so as to form the plate stack S. Here, the individual plates' 1 transverse edges 14a lying in the plane of the longitudinal edges 12 form the inflow cross-section Z1 or, respectively, the outflow cross-section A1 of the flow channels for the medium flowing between the pairs P of plates. The individual plates' 1 transverse edges 14b extending in the plane of the contact surfaces 13 form the inflow cross-sections Z2 or, respectively, the outflow cross-sections A2 for the other medium which flows between the individual plates 1 of each pair P of plates in the same direction or in the direction counter to the first medium. FIG. 1, which shows a countercurrent heat exchanger, illustrates that due to the diagonal arrangement of the inlet and outlet openings, the inflow cross-sections Z1 and Z2, respectively, for the one medium are located next to outflow cross-sections A2 and A1, respectively, for the other medium, namely offset in each case by half the height of a pair P of plates.

(12) FIG. 2a shows an individual plate 1 according to the invention, the inflow cross-section Z1 of which extends over half the width of the individual plate 1, from the longitudinal center up to the longitudinal edge 12. The individual plate has an inlet region E, the length of which in the main flow direction characterizes the path which the inflowing medium requires to spread over the full width of the individual plate 1. In the image plane, four guide blades 2 are arranged to the right of the longitudinal center of the individual plate 1, each of which comprises one inflow leg 21 and one outflow leg 22. The inflow legs 21 and outflow legs 22 are approximately of the same length and enclose an angle of approximately 140 to 100 between them. None of the outflow legs 22 protrudes beyond the longitudinal center of the individual plate 1. The inflow legs 21 are in each case attached in close vicinity to the transverse edge 14a. The individual plate 1 has a turbulence-generating profiling 31, 32 which extends over the entire width of the individual plate up to the contact surfaces 13. Said profiling 31, 32 consists of a high number of knobs 31, 32 stamped into the individual plates 1, which knobs extend in the region of the inflow cross-section Z1 up to the guide blades 2 and are recessed in the region to the left of the longitudinal center.

(13) With regard to the image plane according to FIG. 2, S-shaped edge channels 15 are formed in the region of the contact surfaces 13, said channels having a cross-section that is size-variable over their longitudinal extension.

(14) FIG. 2b shows a perspective view of a plate stack S formed from a plurality of individual plates 1. The interaction of the individual plates 1 is clearly visible in this illustration.

(15) FIG. 3 shows such an edge channel 15 in an enlarged top view. FIGS. 4a, 4b and 4c show sectional views of this edge channel 15 at different sections A, B and C according to FIG. 3. It can be seen that the cross-section through which the medium flows is at its maximum at the position A, whereas the cross-section at the positions B and C is in each case less than 50% of the maximum cross-section, wherein the cross-section at the positions B and C is in each case narrowed on different sides of the edge channel 15. Here the restrictions result from stamped embossments which, with regard to the image plane according to FIG. 3, are shaped as a partial circle, so that in the longitudinal direction, the overall S-shaped course of the channel is obtained.

(16) The invention functions such that the heat medium, here the flue gas, flowing through the inflow cross-section Z1 into the individual plate 1, impinges onto the guide blade's 2 inflow legs 21 immediately adjacent to the transverse edge 14a. From there, the flue gas is guided onto the outflow legs 22 which are arranged at an angle of approximately 140 to 100 relative to the inflow legs 21. Due to the fact that the inlet region E in the region of the inflow cross-section Z1 has a profiling 31, 32 arranged immediately subsequent to the guide blades 2 while there is no profiling 31, 32 in the inlet plate's 1 region located mirror-symmetrically on the left next to the longitudinal center, a pressure distribution develops above the profiling 31, 32 within the inlet region E, which pressure distribution sucks the inflowing flue gas from the guide blades 2 into the profile-free region. In this manner, the flue gas is uniformly distributed over the width of the plate and provides for a homogenous heat flow rate over the entire inlet plate 1 of the heat exchanger. Due to the particularly short and steep configuration of the guide blades 2, adherence of dirt particles on the guide blades 2 is reduced so that clogging of the inflow cross-section Z1 is prevented. Therefore, all in all, a low-maintenance plate heat exchanger is created which is not subject to a performance loss.

(17) According to an embodiment variant, the individual plate 1 can comprise, in addition to the above-illustrated measures, edge channels 15 which, for the purpose of forming a labyrinth, comprise stamped embossments 33. Here, the medium reaching the edge region of the individual plate 1 flows through the edge channels 15 and arrives at the restrictions and expansions of the respective channel cross-sections which cause a backup effect and result in an increased interaction of the medium with the individual plate 1. As shown in FIG. 3, the flue gas gets into the S-shaped edge channels 15 where the whole channel cross-section is available in the section area A (view FIG. 4a). In the region of section B (view FIG. 4b), the flue gas has to flow through the first curve in which the cross-section is reduced by half. In the course of this, the aforementioned backup effect is generated. Downstream of the curve, the cross-section expands again temporarily and decreases again in the region of section C (FIG. 4c) to half the cross-section; however, here it follows the S-shape of the edge channel 15 in the region of the opposing channel side wall. Therefore, all in all, performance losses which, according to the prior art, occur due to bypasses in the edge region of the individual plate 1, are considerably reduced through higher interaction of the heat medium with the individual plates 1, which, in turn, results in increased performance of the heat exchangers. This effect can be enhanced in 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 facilitates avoiding bypasses and therefore results in improved performance of the heat exchanger.

LIST OF REFERENCE CHARACTERS

(18) A Outlet region A1 Outflow cross-section A2 Outflow cross-section E Inlet region P Pair of plates S Plate stack Z1 Inflow cross-section Z2 Inflow cross-section 1 Individual plate 11 Bottom 12 Longitudinal edge 13 Contact surface 14a Transverse edge 14b Transverse edge 15 Edge channel 2 Projection 21 Inflow leg 22 Outflow leg 31 Individual knob 32 Individual knob 33 Stamped embossment