DE2910005A1 - Simple heat exchanger for e.g. electric machines - comprises stacked units, each consisting of corrugated sheets forming parallel channels - Google Patents

Abstract

The heat exchanger consists of several units each comprising two corrugated metal sheets welded together to form parallel channels. The first fluid flows through these channels. The second fluid flows around the outside of the sheets and its flow is bounded by the holders holding the unit. The units are stacked one on top of the other; their holders acting simultaneously as supports and spacers. Each sheet is press formed so that when the two sheets are brought together the channels have hexagonal (or polygonal) cross-sections. The parts of the sheets between the channels touching one another are welded together (or otherwise fixed).

Description

29 IC · - "5

SIEMENS AKTIENGESELLSCHAFT Our reference Berlin and Munich VPA 79 P 3 04 0 BRD

Heat exchanger

The invention relates to a heat exchanger according to the preamble of claim 1.

Heat exchangers of this type, as they are preferably used for closed, Circulation-cooled electrical machines are provided, are objected to from each other Surface elements made of sheet metal with cooling tubes soldered or welded onto them parallel to one another formed, the ends of the cooling tubes through which the external cooling medium flows in plate-shaped ends Holding parts are attached, which limit the space for the inner cooling medium at the front.

The fastening of the cooling tubes in the plate-shaped Retaining parts must be tight, which is a complex manufacturing process conditional. Soldering or welding the cooling tubes onto the surface elements is also complex and the direct heat transfer from the cooling tubes to the surface elements due to the linear, small-area * Contact points are limited, so only a limited one

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Heat quantity from the cooling pipes slowly through heat conduction can flow away and thus the heat transfer only takes place from a partial surface of the cooling unit to the external cooling medium. The diameter and thus the clear cross-sections of the cooling tubes are limited, so that such heat exchangers practically only suitable for liquid as a cooling medium inside the pipe.

The invention is based on the object of creating a heat exchanger of the type mentioned at the outset, the one less effort in production, greater freedom of movement in the choice of cooling channel cross-sections according to the shape and size and better heat dissipation through enlarged Allowed heat transfer surfaces and thereby in particular as Gas / gas heat exchanger is suitable.

The task at hand is solved in a simple manner Weiae through the measures according to the characterization of the patent claim 1 .

The individual cooling units can easily be made from be formed known roll-welded and inflated sheet metal blanks, the between the parallel welding zones inflated bulges form the cooling channels.

The cooling units can also be made of welded or Corrugated sheets connected in a different way be formed, the corrugated sheets advantageously interlocking transverse corrugations may have for stiffening and for swirling the cooling medium flowing through the cooling channels. the Flow outside the cooling channels can experience a directional guidance through the transverse beads. The through a Turbulence achievable reduction of the boundary layer thickness of the flow can also be reduced by transverse beads Height can be reached, these transverse beads do not need to fit into one another.

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The ends of the cooling units on the front side can be adapted from or aich matching, stackable closing bodies and these in pre-libaren profile frames be fixed. The closing bodies can be held together in a sealed manner by curable adhesives or permanently elastic masses will. If the cooling units are arranged freely, the closing bodies have at least theirs The sides facing the cooling units have an appropriate matching one Contour and can be flat on the opposite sides, which makes tight stacking easier, ala the cooling units can be adjusted in relation to each other before being pressed together by the profile frame. When ordered of the cooling units on a gap, the internal closing body can be made from a band with a constant cross-section consist of permanently elastic plastic.

All closing bodies are just like the cooling units of the same shape and size, which greatly simplifies storage. They can be cut to length as required.

In the manufacture of the cooling units from inflatable Expandable blanks can end the still flat blanks between the closing bodies clamped in the profile frame are clamped inflated, so that the closure body serve as at least one end shape-giving profile gauges and a subsequent assembly of the inflated and previously stored inflatable plates can be dispensed with.

Purely the surface elements can serve as casting molds thin-walled closure body held together for producing a stackable one that remains on the cooling unit Serve end part, which are removed after the end part has hardened. The clamped in the profile frame End parts are used for tight stacking.

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Cooling units can also be made from the two surface elements be formed with integrally formed stackable end parts such that the ends of the cooling channels of a cooling unit upstream flat end parts on each end face form a common connection space for all cooling channels, which improves the inflow and outflow of the external cooling medium and, depending on the position of its boundary walls, too enables direct lateral supply and / or removal of the relevant cooling medium. 10

Some exemplary embodiments of the invention are explained below with reference to the drawing. Show it

Figure 1 is an end perspective view of part of a Heat exchanger with holding parts before joining,

2 shows a part of a cooling unit to be assembled from corrugated sheets with transverse beads,

3 shows the front view of two stacked cooling units with superimposed Künl channels and these molded upstream connection spaces on each Front side,

Fig. 4 is a plan view of the subject of fig. 3,

Figure 5 is a front view of two stacked cooling units with staggered and interlocking surfaces,

Fig. 6 front view of cooling channels of special dimensions.

The heat exchanger of Fig. 1 contains from inflated Cooling units 1. The two plates are welded to one another at the flat points 1b or otherwise connected and have bulges 1 a that have arisen as a result of inflation and which the cooling channels 4 form. The cooling channels 4 are part of the entire circuit board,

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so that thereby an unhindered flow of heat away from the cooling channels to all sides within the cooling units can be done.

The ends of the cooling units 1 are tightly inserted between the stackable and adapted to the outer contours of the cooling units sides 2b and smooth sides 2a having connecting bodies 2 and these are clamped in a profile frame 3, which is indicated in the drawing slightly removed from these, but tight in operation is present. The cooling channels 4 of a cooling unit 1 are arranged offset to the cooling channels 4 of the respective adjacent cooling units so that the clear cross-sections for the inner cooling medium between the cooling units are practically the same everywhere. This is the case when, according to FIG. 6, given the shape of the double trapezoid ABCDC ¹ B ', neglecting the wall thickness, the length DA * BC + 2.d.tg Ί. The angle \ BAB '= 2 «4 and d are practically everywhere the same distance between the opposing flat surfaces of the cooling units stacked on a gap. If the flow resistances of the two cross-sectional systems are considered to be the same (which is usually not the case), the optimum d_ can be derived from the requirement that the volumes (cross-section χ unit length J. paper plane) of both systems within the unit cell JX ₁ X ₂ X ₅ X.! must be the same, the wave-like paths for the inner cooling medium (cross-flow cooler) result in cooling-favorable vortices with relatively small flow resistances.

Fig. 2 shows a cooling unit, which consists of two corrugated metal sheets with bulges 5a and planar surfaces in between Places 5b welded together or otherwise connected. Transversely to the cooling channels 6 are in uniform Spacing of interlocking transverse beads 7 and 8

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see that stiffen the cooling unit and vortex-generating in the cooling channels 6 with an unchanged clear cross-section Form guide surfaces for the internal cooling medium. The transverse beads 7 each protrude into the interior of the cooling channels 6 before, whereas the transverse beads 9 form corresponding grooves in the interior of the cooling channels.

You cooling units according to FIGS. 3 and 4 consist of each two pressed surface elements 9, the parallel bulges 9a to form cooling channels 10 and planar points 9b in between, at which they come together welded or otherwise connected. At the front ends of each surface element 9 are bent flat end parts 9c are provided, which allow a spaced stacking of cooling units, wherein the end parts 9c form a connection space common to all cooling channels 10, which the supply and discharge of the external cooling medium allowed from the front or the side. The cooling channels 10 are each one above the other, so that for the inner Cooling medium almost identical (staggered arrangement) or changing (aligned arrangement) clear cross-section.

A particularly space-saving arrangement of the cooling units 11 can be achieved according to FIG. 5 in that the Cooling units are spaced with their cooling channels 12 on a gap and interlocking, so that practically result in constant liohte cross-sections for the inner cooling medium.

10 claims
6 figures

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Claims (10)

VPA 79 P 3 0 Ί 0 BRD Claims Heat exchanger with a first cooling medium on the inside flowed around parallel, circumferentially closed and cooling channels connected to surface elements for a second (outer) cooling medium, the end-side, the Space for the first cooling medium frontally delimiting holding parts are included, characterized in that at least two by opposite- lying parallel bulges in two at the intermediate points at least on the outer ones Boundaries sealingly adjacent surface elements formed cooling channels form a cooling unit and at least two such cooling units are spaced apart from one another by the holding parts. 2. Heat exchanger according to claim 1, characterized that the individual cooling units are arranged in parallel planes with their Cooling channels are parallel to each other. 3. Heat exchanger according to claim 1 and 2, characterized in that the cooling channels of the adjacent cooling units offset to one another with a gap are. 4. Heat exchanger according to claim 3, characterized that the cooling channels of a cooling unit are each in the one between the cooling channels The spaces of the adjacent cooling units protrude and the width of the cooling channels is equal to the width of the intermediate ones Make adapted iat that there is essentially the same flow cross-section for the first cooling medium everywhere result. 01003870422 BATH ORIGINAL O] · ■): \ '■■'. r - 2 - VPA 79 P 3 O ^ O BRD 5. Heat exchanger according to one of the preceding claims, characterized in that the two surface elements forming a cooling unit are transverse to the Bulges have extended interlocking, stiffening transverse beads that remain in the cooling channels Form clear cross-section vortex-generating guide surfaces for the second cooling medium. 6. Heat exchanger according to one of the preceding claims, characterized in that the Form transverse beads with the longitudinal direction of the cooling channels from 90 directions deviating, so that the transverse beads for Contribute flow guidance between the cooling units. 7. Heat exchanger according to one of the preceding claims, characterized in that transversely to the flow direction a multitude of transverse beads from low elevation are attached to the surfaces. 8. Heat exchanger according to one of the preceding claims, characterized in that each cooling unit on both end faces each with a one common connection space for its cooling channels "forming stackable end part combined into one structural unit is and the sealingly stacked end parts of all cooling units from a holding frame on each end face are held together. 9. Heat exchanger according to one of the preceding claims, characterized in that each Cooling unit is formed at its ends so that the cooling units can be stacked in a sealing manner without additional end parts are. 10. Heat exchanger according to one of the preceding 030031/0 422 originally inspected - 3 - VPA 79 P 3 O 4 O BRD Claims, characterized in that that the cooling channels in the cooling units are of different sizes and different distances from one another to have. 0 * 0031/0422 ORIGINAL INSPECTED