GB1592069A

GB1592069A - Heat exchange plate for heat-exchangers

Info

Publication number: GB1592069A
Application number: GB3839677A
Authority: GB
Original assignee: Pasilac AS
Current assignee: Pasilac AS
Priority date: 1976-09-16
Filing date: 1977-09-14
Publication date: 1981-07-01
Also published as: DK417676A; FR2365094A1; DE2741712A1

Description

(54) HEAT EXCHANGE PLATE FOR HEAT EXCHANGERS (71) We, PASILAC A/S, a Danish Joint Stock Company of Box 320, 8600 Silkeborg, Denmark, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a heat exchanger plate for heat exhangers of the type having a frame with fixing members for a stack of heat exchange plates.

In such heat exchangers each plate is normally provided with an edge packing which bounds the flow area between the plate and the adjacent plate of the stack.

Medium is supplied to and removed from this space through holes in the plates which are preferably at the plate corners. The plates are clamped tightly together in the frame.

It is necessary, of course to obtain tightness between the plates of the stack and to ensure accurate positioning of the plates relative to each other, while in order to increase their heat transmission capacity the plates are often provided with corrugations, such corrugations being in some cases of such a shape that the plates engage with each other thereby, which contributes towards accurate fixing of the plates relative to each other.

For their insertion into the frame, the plates are normally provided with recesses in which are engaged the frame fixing members which are girder-shaped.

If it is desired to use the fixing members as aids for accurate relative positioning of the plates, narrow tolerances will be required for them and for the recesses. This will be especially the case where the plates are not provided with corrugations which contribute towards fixing of the plates relative to each other, so that expensive machining of the profiles of the fixing members is necessary.

In known plates the recesses are bounded by tabs which interact with the fixing members, and these are often rather weak which does not help in achieving accurate positioning. This applies especially in cases where because of the heat transmission capacity and the cost of the material, the plates are made of as thin a starting material as possible, for example when the material is titanium. The result is a mechanically weak plate and little possibility of providing strong and accurate assembly and deep corrugations.

According to the present invention there is provided a heat exchange plate for a heat exchanger which has a frame with fixing members extending through a stack of heat exchange plates, such plate being shaped to define means to engage the fixing members, wherein, in the region of the engaging means the plate has a separate fixing device attached to it and a recess arranged for reception of a corresponding fixing device on an adjacent plate of the stack, the separate fixing device being a bent plate element, one leg of which is connected to and parallel to the plane of the heat exchange plate and the other leg of which projects transversely of the plane of the plate.

With the invention, the heat exchange plate is provided with fixing aids which, without requiring careful machining of the fixing members of the frame and without requiring a very large plate thickness, will provide secure and effective alignment of the plates relative to each other. The separate bent plate elements are easy to make, and in actual practice it will often be possible to employ the roundels of plate material which remain when corner holes are punched in the plate. It is preferable for said one leg to be formed as a reinforcement for the engaging means of the heat exchange plate, while the recess can also be part of the bent plate element. Because it can be made in the element, this precise alignment.

The one leg of the angularly bent plate element, connected to the heat exchange plate, can have a rib extending transversely of the other leg and projecting from the one leg in the same direction as the other leg. The rib will reinforce the bent plate element and will support the other leg. The rib can also act as a spacer when it is given the same height as other spacer devices with which the plate can be equipped.

The rib can also form a channel which is open at both ends, one end opening into said other leg so that it can form a drain e.g. for water originating from outside on cleaning of the heat exchanger.

If heat exchange plates are equipped with spacer devices for defining the distance between two adjacent plates, these devices are usually in the form of ribs crossing each other in the pair of plates, or bosses formed in the plate material. Such bosses cannot be positioned identically for two adjacent plates since the boss of one plate will be opposite to the corresponding dent formed in the other plate. According to a preferred feature of the invention the heat exchange plate can be such that the one leg of the angularly bent plate element has at least one spacing rib or boss, and the heat exchange plate itself closes the groove thereof. Alternatively, in the area covered by the one leg the heat exchange plate itself has at least one rib or boss formed therein as a spacer, and the groove thereof is closed by the said one leg.In either case the groove will be closed which means that in the area in question it is possible to use ribs or bosses with the same position and the same orientation on all plates of the stack, which results in a very advantageous pillar-like support throughout the plate stack.

In actual practice it will normally be sufficient to have a single fixing device in accordance with the invention for each fixing member of the frame, but there is nothing to prevent several separate devices from being used. Since the heat exchange plates are normally secured to the frame at opposite ends, separate fixing devices are suitably positioned correspondingly, for example, one device at the upper end and one device at the lower end of the plate.

In order that the invention may be more clearly understood, the following description is given by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a schematic view of a conventional plate heat exchanger with a plate stack composed of heat exhange plates; Fig. 2 is schematic view of a conventional heat exchange plate for use in such a heat exchanger; Fig. 3 shows on a larger scale one end of such a plate having thereon a separate fixing device according to the invention; Fig. 4 shows the same item as Figure 3 viewed from the opposite side; Fig. 5 is a section of a plate according to the invention with a different form of fixing device; Fig. 6 is a section along the line VI VI of Figs. 4 and 5 through a stack of the plates shown herein; Fig. 7 is a section of a plate of a third form according to the invention;; Fig. 8 shows a partial cross-section of a plate of the invention with an additional optional feature; and Fig. 9 shows a modification of the feature of Figure 8.

Fig. 1 shows a stack of heat exchange plates 1 placed between girder-shaped carrying and fixing members 2a of a supporting frame 2. At their opposite ends the heat exchange plates I are each provided with carrying tabs 3 which bound a recess 4 which receives the girders 2a; the tabs and recess comprising engaging means to engage the fixing members 2a of the frame.

At the position indicated by numeral 5 the heat exchange plate 1 has a resilient edge packing 5 for limitation of a flow area 6 which together with a corresponding area of an adjacent plate defines a flow space in the heat exchanger. The flow area 6 is corrugated. Together with ribs 7 and bosses 8 formed in the plate material of the heat exchanger plate, the corrugations of the flow areas 6 form spacer means between adjacent plates. The plates each have four apertures 114 at their corners.

Figs. 3 and 4 show one form of fixing device 9 according to the invention. The device is an angularly bent plate element of which one leg 10 is welded to the plate 1, and the other leg 11 extends generally perpendicular therefrom. The leg 11 is positioned in a recess 12 formed in the edge of plate 1, and the width of the leg 11 is substantially equal to or slightly smaller than the width of the recess 12. Thus, when a plurality of such plates are stacked, the leg 11 on one plate extends accurately into the recess 12 of the next so as to provide accurate alignment, with the previously described corrugations, ribs and bosses giving accurate spacing.

The shape of the leg 11 is more apparent from Fig. 6. It has an inclined ascending part I la, a central part I ib which is, in the main, perpendicular to part I Ia, and an inclined ascending end part I lc extending from the central part. The leg is shaped and sized in such a way that when the plates are clamped together, the end part 1 lc of one heat exchange plate I of the stack bears against the central part I lb of the fixing device of the adjacent plate as shown at the left in Figure 6, which shows other plates in the process of assembly.

On the leg 10 of the plate element 9, a rib 13 is situated extending transversely of the leg II and projecting from the same side of the leg 10 as the leg 11. The rib 13 is of the same height from the plate as the ribs 7 and the bosses 8. The rib 13 forms a channel which is open at both ends.

In the embodiment shown in Fig. 5 the leg 10 is constructed as a reinforcement 14 which not only supports the leg 11 but also strengthens the plate in the region of the recess 4 and particularly the tabs 3.

In the embodiment shown in Fig. 7, a part 14a of the reinforcing plate element 14 shown in Fig. 5 extends above the bottom edge of the recess 4 in the plate, and the leg 11 is bent out from this part and as a result forms a recess 12a in the element 14 corresponding to the recess 12 of other embodiments.

Figs. 8 and 9 show details of embodiments with spacer bosses 15 and 16 respectively provided in the area of the reinforcement 14 shown in Fig. 5. As shown in Fig. 8, the bosses 15 are formed in the material of the reinforcement part 14, and the resultant groove is covered by the material of the heat exchange plate 1 itself. As shown in Fig. 9, the bosses 16 are formed in the material of the heat exchange plate 1 itself and covered by the reinforcement part 14. In both cases the bosses 15 and 16 can be in the same position and orientation in each plate and result in a pillar-like support through the plate stack. Instead of bosses, ribs can be provided.

WHAT WE CLAIM IS: 1. A heat exchange plate for a heat exchanger which has a frame with fixing members extending through a stack of heat exchange plates, such plate being shaped to define means to engage the fixing members, wherein, in the region of the engaging means the plate has a separate fixing device attached to it and a recess arranged for reception of a corresponding fixing device on an adjacent plate of the stack, the separate fixing device being a bent plate element, one leg of which is connected to and parallel to the plane of the heat exchange plate and the other leg of which projects transversely of the plane of the plate.

2. A heat exchange plate as claimed in claim 1, wherein the said one leg of the plate element is in the form of a reinforcement of the engaging means of the plate.

3. A heat exchange plate as claimed in claim 1 or 2, wherein the recess is formed in the bent plate element.

4. A heat exchange plate as claimed in any one of claim I to 3 wherein said one leg of the bent plate element has a rib extending transversely of the other leg and projecting from said one leg in the same direction as said other leg.

5. A heat exchange plate as claimed in claim 4, wherein the plate is provided with spacer devices for interaction with adjacent plates of a plate stack and wherein the rib is of the same height as such spacer devices.

6. A heat exchange plate as claimed in claim 4 or 5, wherein the rib forms a channel open at both ends, one end of the channel opening through the other leg of the bent plate element.

7. A heat exchange plate as claimed in any of claims I to 6, wherein said one leg of the bent plate element has, formed therein, at least one rib or boss to act as a spacer device, the heat exchange plate itself closing the resultant groove.

8. A heat exchange plate as claimed in any of claims 1 to 6, wherein in the area covered by said one leg of the bent plate element the heat exchange plate itself has at least one rib or boss to act as a spacer device and the resultant groove is closed by the said one leg.

9. A heat exchange plate as claimed in any preceding claim, wherein each separate fixing device has a contact face to be engaged by part of a corresponding fixing device of a neighbouring plate.

10. A heat exchange plate as claimed in claim 9, wherein the contact face is constituted by a central part of the other leg of the bent plate element.

11. A heat exchange plate substantially as hereinbefore described with reference to and as shown by Figures 3 to 9 of the accompanying drawings.

12. A heat exchanger comprising a frame carrying a stack of heat exchanger plates according to any one of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. 14a of the reinforcing plate element 14 shown in Fig. 5 extends above the bottom edge of the recess 4 in the plate, and the leg 11 is bent out from this part and as a result forms a recess 12a in the element 14 corresponding to the recess 12 of other embodiments. Figs. 8 and 9 show details of embodiments with spacer bosses 15 and 16 respectively provided in the area of the reinforcement 14 shown in Fig. 5. As shown in Fig. 8, the bosses 15 are formed in the material of the reinforcement part 14, and the resultant groove is covered by the material of the heat exchange plate 1 itself. As shown in Fig. 9, the bosses 16 are formed in the material of the heat exchange plate 1 itself and covered by the reinforcement part 14. In both cases the bosses 15 and 16 can be in the same position and orientation in each plate and result in a pillar-like support through the plate stack. Instead of bosses, ribs can be provided. WHAT WE CLAIM IS:

1. A heat exchange plate for a heat exchanger which has a frame with fixing members extending through a stack of heat exchange plates, such plate being shaped to define means to engage the fixing members, wherein, in the region of the engaging means the plate has a separate fixing device attached to it and a recess arranged for reception of a corresponding fixing device on an adjacent plate of the stack, the separate fixing device being a bent plate element, one leg of which is connected to and parallel to the plane of the heat exchange plate and the other leg of which projects transversely of the plane of the plate.