Heat exchanger with collecting channel for discharging a liquid phase

Abstract

A heat exchanger for indirectly exchanging heat between a first medium and a second medium, the heat exchanger having a easing enclosing an encased area for receiving the liquid phase of the first medium and at least one plate heat exchanger arranged in the encased area for receiving the first medium and the second medium. The plate heat exchanger is surrounded by the liquid phase of the first medium during operation. A collecting channel is located in the encased area in order to allow for discharge of part of the liquid phase of the first medium from the encased area.

Claims

1. A heat exchanger for the indirect exchange of heat between a first medium and a second medium, said heat exchanger comprising: a casing having a longitudinal axis and defining an encased area for receiving a liquid phase of the first medium, wherein said longitudinal axis extends in a horizontal direction, a plate heat exchanger having first heat transfer passages for receiving the first medium, and second heat transfer passages for receiving the second medium, said first and second heat exchange passages permitting heat to be indirectly be exchanged between the first and second mediums, wherein the plate heat exchanger is arranged within the encased area such that the plate heat exchanger can be surrounded with a liquid phase of the first medium located in the encased area, a collecting channel arranged in the encased area for collecting the liquid phase of the first medium located in the encased area before it can be discharged from the casing, and an outlet connecting pipe connected to the casing and in direct fluid communication with the collecting channel for discharging the collected liquid phase from the casing, wherein the collecting channel comprises a wall fixed to the casing at a position underneath the plate heat exchanger such that the wall and the casing together define an interior area of the collecting channel, and said wall having a longitudinal axis which extends substantially parallel to said longitudinal axis of said casing, and wherein said wall comprises a top wall part arranged between the plate heat exchanger and the casing, and a side wall part extending from the perimeter of the top wall part to directly contact the casing such that the side wall part circumscribes the interior area between the top wall part and the casing.

2. The heat exchanger in accordance with claim 1, wherein the collecting channel is arranged below said longitudinal axis of said casing.

3. The heat exchanger in accordance with claim 1, wherein said encased area includes a region above the plate heat exchanger wherein a gaseous phase of the first medium, generated by the indirect exchange of heat between the first medium and the second medium within said plate heat exchanger, can be collected.

4. The heat exchanger in accordance with claim 1, wherein the first heat transfer passages of the plate heat exchanger are arranged so that the first medium can flow vertically in the first heat transfer passages, and the second heat transfer passages are arranged so that the second medium can flow in counter-flow with respect to flow of the first medium.

5. The heat exchanger in accordance with claim 1, wherein said encased area contains a plurality of plate heat exchangers.

6. The heat exchanger in accordance with claim 1, wherein the wall of the collecting channel is below said longitudinal axis.

7. The heat exchanger in accordance with claim 1, wherein the outlet connecting pipe opens centrally, with respect to the longitudinal extent of the wall, into the interior area of the collecting channel.

8. The heat exchanger in accordance with claim 1, wherein transverse to the longitudinal axis of the wall, the interior area of the collecting channel has a cross-section that increases towards the outlet connecting pipe.

9. The heat exchanger in accordance with claim 1, wherein the collecting channel has a plurality of inlet openings for inflow of the liquid phase of the first medium into the collecting channel, wherein the inlet openings are formed in the top wall part and/or the side wall part.

10. The heat exchanger in accordance with claim 9, wherein said collecting channel further comprises two end wall parts connected to said top wall part and said side wall parts and wherein said inlet openings are arranged next to one another in said top wall part and/or said side wall part along the longitudinal axis of the wall and the distance between adjacent inlet openings reduces from a center of the wall towards longitudinal ends of the wall.

11. The heat exchanger in accordance with claim 9, wherein said inlet openings are provided in said top wall part and are slot shaped, and said inlet openings are provided in said side wall part and are circular in shape.

12. The heat exchanger in accordance with claim 1, wherein the casing comprises a cylindrical wall formed about the longitudinal axis of the casing and two end walls that are transverse to the longitudinal axis of the casing, and wherein said cylindrical wall connects said two end walls to one another.

13. The heat exchanger in accordance with the claim 12, wherein the outlet connecting pipe is arranged in said cylindrical wall below said collecting channel of the casing.

14. The heat exchanger in accordance with claim 12, wherein transverse to the longitudinal axis of the wall, the interior area of the collecting channel has a cross-section that increases towards the outlet connecting pipe.

15. The heat exchanger in accordance with claim 14, wherein the collecting channel has a plurality of inlet openings for inflow of the liquid phase of the first medium into the collecting channel, wherein the inlet openings are formed in the top wall part and/or the side wall part of the collecting channel.

16. The heat exchanger in accordance with claim 1, wherein the first heat transfer passages of the plate heat exchanger are arranged so that the first medium can flow vertically in the first heat transfer passages, and the second heat transfer passages are arranged so that the second medium can flow in cross-flow with respect to flow of the first medium.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

(1) Further details and advantages of the invention are to be explained by the following description of an example of embodiment with the aid of the figures.

(2) FIG. 1 shows a view in cross-section of an inventive heat exchanger,

(3) FIG. 2 shows a further view in cross-section of the heat exchanger along the line II-II in FIG. 1,

(4) FIG. 3 shows a plan view onto an inventive collecting channel of the heat exchanger in accordance with FIGS. 1 and 2, and

(5) FIG. 4 shows a cross section view of the heat exchanger of FIG. 1 with two plate heat exchangers.

(6) FIG. 1 shows, in conjunction with FIGS. 2 and 3, a heat exchanger 1, which has a transverse (circular) cylindrical casing 2, which bounds an encased area 3 of the heat exchanger 1. Here the casing 2 has a cylindrical peripheral wall 14, which is bounded on its end faces by two walls 15 located opposite one another.

(7) As shown in FIG. 1, a plate heat exchanger 4 is arranged in the encased area 3 enclosed by the casing 2; this has a plurality of parallel heat transfer passages. FIG. 4 illustrates an embodiment in which a plurality of plate heat exchangers 4 are arranged in the encased area 3 enclosed by the casing 2.

(8) The plate heat exchanger 4 here has a number of e.g. corrugated or folded sheets (so-called fins), which in each case are arranged between two plane separating plates or sheets of the plate heat exchanger 4. In this manner a multiplicity of parallel channels, that is to say, heat transfer passages, are formed between each pair of separating plates (or between a separating plate and a cover plate, see below), through which the respective medium F1, F2 can flow. The two outermost layers are formed by cover plates of the plate heat exchanger 4; to the sides cover plates are provided between each pair of adjacent separating plates, or separating plates and cover plates.

(9) During operation of the heat exchanger 1 the encased area 3 is filled with a first medium F1 via an inlet connecting pipe 60 that is provided on an upper face 8 of the casing 2. This inlet flow into the heat exchanger 1 is usually two-phase, but can also be solely in liquid form. The liquid phase L1 of the first medium F1 then forms a bath surrounding the plate heat exchanger 4, wherein the gaseous phase G1 of the first medium F1 collects above the liquid phase L1 in an upper region 34 of the encased area 3.

(10) The liquid phase L1 of the first medium F1 can rise in assigned first heat transfer passages of the plate heat exchanger 4, and thereby is partially vaporized as a result of indirect heat transfer from a second medium F2 that is to be cooled, which, e.g. in cross-flow to the first medium F1, is led in assigned second heat transfer passages of the plate heat exchanger 4. The gaseous phase G1 of the first medium F1 that is thereby generated can exit at an upper end of the plate heat exchanger 4 and rises in the encased area 3 of the heat exchanger 1, from where it can be discharged via appropriate outlet connecting pipes 40 on the upper face 8 of the casing 2.

(11) Furthermore, a part of the liquid phase L1 circulates in the encased area 3, wherein that part is raised from bottom to top in the plate heat exchanger 4 in the first heat transfer passages, and then once again flows downwards in the encased area 3 outside the plate heat exchanger 4.

(12) The second medium F2 is led into the plate heat exchanger 4 via a suitable inlet connecting pipe O, and after passing through the assigned second heat transfer passages is discharged from the plate heat exchanger 4 in a cooled or liquefied state via an outlet connecting pipe O.

(13) A box-shaped collecting channel 5 is arranged on the lower face 16 of the heat exchanger 1, on an inner surface 2a of the casing 2 facing towards the encased area 3; the collecting channel 5 extends along an extension direction 7. Here the collecting channel is, in particular, designed in an elongated manner, and accordingly has a larger extent along the extension direction 7 than it has transverse to the same extension direction 7.

(14) Furthermore, the collecting channel 5 has a wall W, which bounds an interior area I of the collecting channel 5, through which the liquid phase L1 of the first medium F1 can be discharged out of the encased area 3. In detail the wall W has an upper face 9, together with two side walls 11 extending from the latter, which extend along the extension direction 7 and are connected with one another via a floor (lower face) 10 of the collecting channel 5 located opposite to the upper face 9, which floor is formed by the casing 2. Furthermore, the collecting channel 5, that is to say, its wall W, has two end faces 11a, 11b, which are located opposite one another along the extension direction 7.

(15) For purposes of an, in particular continuous, discharge of the liquid phase L1 of the first medium F1 out of the encased area 3 during operation of the heat exchanger 1, inlet openings 13, preferably circular-shaped, are now provided on the sidewalls 11, and/or inlet openings 12, preferably slot-shaped, are now provided on the upper face 9 of the collecting channel 5, through which the liquid phase L1 can enter into the collecting channel 5. The inlet openings 12, 13 are thereby arranged next to one another along the extension direction 7, wherein the distance between adjacent inlet openings 12, 13, starting from the outlet connecting pipe 6, preferably reduces along the extension direction 7 towards each of the two end faces 11a, 11b of the collecting channel 5. At the same time the longitudinal axes of the slot-shaped inlet openings 12 in each case run transverse to the extension direction 7 of the collecting channel 5.

(16) The collecting channel 5 is furthermore connected with an outlet connecting pipe 6 of the casing 2, which enters into the collecting channel 5 on the lower face 10 of the collecting channel 5, such that the liquid phase L1 of the first medium F1 that has entered into the interior area I of the collecting channel 5 can be discharged from the collecting channel 5 via the outlet connecting pipe 6.

(17) The outlet connecting pipe 6 is preferably arranged centrally on the collecting channel 5, along the extension direction 7, wherein the upper face 9 of the connecting channel 5 preferably has two sections 9a, 9b rising towards the outlet connecting pipe 6, which preferably meet above the outlet connecting pipe 6.

(18) Starting from the end faces 11a, 11b, the cross-section of the collecting channel 5 in each case preferably increases (widens) in the direction towards the outlet connecting pipe 6 in order to obtain as homogeneous a velocity field of the liquid phase L1 of the first medium F1 as possible in the collecting channel 5. In particular, the flow of the liquid phase L1 in the adjacent encased area 3 should also thereby be negatively influenced as little as possible.

LIST OF REFERENCE SYMBOLS

(19) 1 Heat exchanger 2 Casing 2a Inner surface 3 Encased area 4 Plate heat exchanger 5 Collecting channel 6 Outlet connecting pipe 7 Extension direction 8 Upper face of the casing 9 Upper face of the collecting channel 9a, 9b Upper face sections 10 Lower face of the collecting channel 11 Side walls of the collecting channel 11a, 11b End faces 12 Slot-shaped inlet openings 13 Circular-shaped inlet openings 14 Peripheral wall of the casing 15 End face walls of the casing 16 Lower face of the casing 33 Lower region of the encased area 34 Upper region of the encased area 40 Outlet connecting pipe for the gaseous phase 60 Inlet connecting pipe F1 First medium L1 Liquid phase of the first medium G1 Gaseous phase of the first medium F2 Second medium 1 Interior area of the collecting channel O Inlet connecting pipe for the second medium O Outlet connecting pipe for the second medium Velocity field of the liquid phase L1 W Peripheral wall of the collecting channel