HK1092865B - A plate-type heat exchanger - Google Patents

Description

Plate heat exchanger

This application is a divisional application of another prior application (application date: 5/8/2004; application number: 200410042162.8; title of the invention: plate heat exchanger with single-wall and double-wall heat transfer plates) filed by the present applicant with the national intellectual property office.

Technical Field

The present invention relates to a plate heat exchanger.

Background

Plate heat exchangers are used to transfer thermal energy between heat exchange fluids. At least two heat exchange streams flow through separate flow path interstices defined between heat exchange plates in the plate heat exchanger. Typically, the heat exchanger plates are arranged in a stacked structure forming part of a plate heat exchanger. Individual flow path voids are formed by through-going holes in the heat exchanger plates. The heat transfer between the at least two heat exchange streams takes place substantially in the area of the central heat transfer portion of the heat exchange plate. In order to transfer thermal energy, one heat exchange flow passes through the flow passage spaces on one side of the heat exchange plate, and the other heat exchange flow passes through the flow passage spaces on the other side of the heat exchange plate. In this way heat is exchanged between the two heat exchange streams flowing in opposite directions through the heat exchange plates.

In addition to plate heat exchangers in which the stacked heat exchanger plates are each designed as single-walled heat exchanger plates with a single plate member, other known heat exchangers are in the form of heat exchangers in which all heat transfer related stacked heat exchanger plates are designed as double-walled heat exchanger plates. The double-walled heat exchanger plate consists of two plate members which are in tight engagement with each other at least in the area of the central heat transfer portion. A double-walled heat exchanger plate may meet higher safety standards than a single-walled heat exchanger plate, since the two heat exchange streams will not mix together if a leak should occur in one of the two plate members of the double-walled heat exchanger plate. The reason for this is that any liquid that seeps out will only seep into the space between the two plate members, in particular into the edge portions, and not to the other side of the heat exchanger plate. A plate heat exchanger consisting of a double-walled heat exchanger plate package is particularly useful in situations where the three separate flow path interspaces for the three heat exchange flows are provided by through-going holes in the heat exchanger plates and intermediate interspaces between the heat exchanger plates in the plate heat exchanger.

Disclosure of Invention

It is an object of the present invention to provide an improved plate heat exchanger, thereby providing a wider use for the use of the plate heat exchanger.

The above object is solved by a plate heat exchanger comprising a heat exchanger plate package consisting of a number of heat exchanger plates fixedly connected to each other and defining between said heat exchanger plates separate flow path interspaces for at least two heat exchange flows, according to the invention a part of said heat exchanger plates being designed as single-walled heat exchanger plates each having one plate member and another part of said heat exchanger plates being designed as double-walled heat exchanger plates each having two plate members.

In this way, a plate heat exchanger can be produced in the form of a single structural element, in which the heat exchange plate pack has a plurality of portions that meet different safety standards. The incorporation of single and double wall heat transfer plates in the same plate heat exchanger allows the heat exchanger to be manufactured for use in a variety of applications which, in part, require the use of more expensive double wall heat exchange plates to ensure that higher safety standards are met. But in addition at least a part of the heat exchanger plates may also be designed as single walls if lower safety standards are sufficient for some of the flow path interspaces defined in the plate heat exchanger. This is especially true if the plate heat exchanger is formed with more than two flow path gaps for the heat exchange flow. In this case, the heat transfer between one heat exchange flow and the other must generally meet high safety standards, requiring a heat exchanger of double-walled design. For the heat transfer between one heat exchange flow and the other, a heat exchanger of single-walled construction may be used if it is sufficient to guarantee a lower safety standard.

In addition, the combination of single-and double-walled heat exchanger plates has the advantage that the plate heat exchanger, which normally consists of double-walled heat exchanger plates, in combination with a single-walled heat exchanger plate, gives full play to a more efficient heat transfer. In addition, the combination of two heat exchanger plates contributes to a reduction of the manufacturing costs compared to known heat exchangers provided with double-walled heat exchanger plates only.

The combined use of single and double wall heat exchanger plates in one plate heat exchanger would be most useful if three separate flow path interspaces for the heat exchange streams were formed between the heat exchanger plates.

Drawings

The invention will be further described by way of embodiments and with reference to the accompanying drawings, in which:

fig. 1 shows a heat exchanger plate package consisting of several heat exchanger plates;

FIG. 2 shows a front view of a plate heat exchanger;

FIG. 3 shows a side view of the plate heat exchanger shown in FIG. 2;

FIG. 4 shows a cross-sectional view of the plate heat exchanger shown in FIG. 2 along the line A '-A' of FIG. 2;

fig. 5 shows an enlarged view of an edge portion of the cross-section shown in fig. 4.

Detailed Description

Figure 1 shows an arrangement consisting of several single-walled heat exchanger plates 1 and several double-walled heat exchanger plates 2. Both heat exchanger plates are each provided with a central heat transfer portion 3 and through-going holes 4 in the corner areas 5. The areas other than the through-holes 4 are formed with embossings 6 forming a surface structure. The embossing 6 enhances the spacing arrangement between the single/double wall heat exchanger plates 1, 2 when the single/double wall heat exchanger plates 1, 2 are used in a plate heat exchanger, thereby defining flow path voids.

Fig. 2 and 3 show a front view and a side view, respectively, of a plate heat exchanger. The plate heat exchanger comprises a heat exchanger plate package 21 arranged in accordance with the single/double wall heat exchanger plates 1, 2 shown in fig. 1, wherein the single/double wall heat exchanger plates 1, 2 are fixedly joined together by means of soldering. In addition, the plate heat exchanger 20 comprises two outer plates 22, 23 provided with connectors 24 for providing and discharging a heat exchange flow. A separate flow path interspace for introducing/discharging a heat exchange flow through the connection 24 is formed between several heat exchanger plates 1, 2. The embossings 6 provoke a highly turbulent heat exchange fluid flow between the several heat exchanger plates 1, 2 in the central heat transfer portion 3 of the single/double wall heat exchanger plates 1, 2.

Fig. 4 shows a cross-sectional view of the plate heat exchanger shown in fig. 2 along the line a '-a' of fig. 2. A heat exchanger plate package 21 consisting of single-and double-walled heat exchanger plates 1, 2 is arranged between the outer plates 22, 23. Fig. 5 shows an enlarged view of the edge portion 25 of the cross-sectional view of fig. 4. It can thus be seen that in the embodiment of the plate heat exchanger 20 shown in the figure, the heat exchanger plate package 21 comprises three double-walled heat exchanger plates 2a, 2b, 2c, each comprising two plate members 2a ', 2a ", 2b ', 2 b" and 2c ', 2c ", respectively. The single-and double-walled heat exchanger plates 1, 2 comprise edges 26 which are bent upwards in relation to the plane of the central heat transfer portion 3. In the illustrated embodiment, an optional outer edge 27 is integrally formed with the edge 26, which outer edge 27 is bent outwardly so as to be substantially parallel to the plane of the central heat transfer portion 3. In an alternative embodiment, the outer edge 27 may be omitted.

As shown in fig. 5, the outer edges 27 of the plate members 2a ', 2a ", 2b ', 2 b" and 2c ', 2c "of each of the double-walled heat exchanger plates 2a, 2b, 2c are arranged spaced apart from each other, while the adjacent double-walled heat exchanger plates 2a and 2b and 2c are tightly joined to each other. Thus, any heat exchange flow that is formed between the plate members 2a ', 2a ", 2 b', 2 b" or 2c ', 2c ", respectively, due to leakage of one of the two plate members 2 a', 2 a", 2b ', 2b "or 2 c', 2 c", and flows to the region of the edge 26 due to capillary action, can already be observed from the outside of the region 28.

In the illustrated embodiment of the plate heat exchanger 20, the single-walled and the double-walled heat exchanger plates 1, 2 are each integrated in a separate heat exchanger plate package 21a, 21 b. But the single-walled and double-walled heat exchanger plates 1, 2 may also be arranged in any combination, e.g. several groups of single-walled/double-walled heat exchanger plates 1, 2 are combined in one plate heat exchanger.

The technical features of the invention disclosed in the above description, the claims and the drawings are essential to the realization of the various embodiments of the invention, individually or in any combination.

Claims (2)

1. A plate heat exchanger (20) comprising a heat exchanger plate package (21) of a number of heat exchanger plates (1, 2) which are fixedly connected to each other and between which separate flow path interspaces are defined for at least two heat exchange flows, characterized in that a part of the heat exchanger plates (1, 2) is designed as single-walled heat exchanger plates (1) each having one plate member, and in that another part of the heat exchanger plates (1, 2) is designed as double-walled heat exchanger plates (2) each having two plate members, the stack of single-walled heat exchanger plates and double-walled heat exchanger plates being arranged between outer plates.

2. A plate heat exchanger according to claim 1, characterized in that between the heat exchanger plates (1, 2) separate flow path interspaces are defined for the three heat exchange flows.