EP0143838B1

EP0143838B1 - Gasket arrangement for a plate heat exchanger

Info

Publication number: EP0143838B1
Application number: EP84902221A
Authority: EP
Inventors: Jarl Anders Andersson; Jan-Ove Bergqvist
Original assignee: Alfa Laval Thermal AB
Current assignee: Alfa Laval Thermal AB
Priority date: 1983-05-20
Filing date: 1984-05-07
Publication date: 1988-01-20
Also published as: DK26685A; BR8406899A; IT1207480B; EP0143838A1; IT8420959A0; NO850219L; JPS60501378A; WO1984004809A1; DE3468938D1; DK26685D0; SE8302861D0

Abstract

A gasket (1; 11; 18) for a plate of a plate heat exchanger, which plate is provided with a gasket groove into which the gasket is intended to be applied. According to the invention the gasket (1; 11; 18) at least at certain places along its extension fills up essentially the whole gasket groove, and the gasket (1; 11; 18) has such a design that necessary expansion space is created for the same in the gasket groove of the plate.

Description

This invention relates to a sealing arrangement for a plate of a plate heat exchanger, the arrangement comprising a groove in the plate and a gasket of elastic material arranged in the groove and filling the cross-sectional area of the groove. Such a sealing arrangement is disclosed in DE-B-1064539.
A plate heat exchanger comprises a number of essentially rectangular plates which are usually supported in a frame. The plates are sealed to each other by means of peripheral gaskets and between the plates are formed heat exchanging passages for throughflow of the heat exchanging media which are conducted to and from the heat exchanger via inlets and outlets preferably arranged at the one end of the plate heat exchanger. In their corner regions the plates are provided with openings for forming inlet channels and outlet channels for the heat exchanging media, the heat exchange passages being connected in parallel between these channels.
The peripheral gaskets which seal between the plates consist essentially of rubber, the sealing pressure of the gaskets being obtained when the plate package is clamped in the frame by means of bolts.
In order that a rubber gasket functions satisfactorily there must, among other things, be sufficient space in the gasket location to allow for an expansion of the rubber caused partly when the gasket is compressed during tightening the plates together and partly as a consequence of possible temperature expansion.
Such an expansion space already exists on certain types of heat exchanger plates due to the fact that recesses are made in the flank of the gasket groove in the heat exchanger plate.
In another type of plate disclosed in Swedish patent No. 116 638, the plate is provided with a gasket groove having a square cross section and the co-operating gasket has a circular cross section. Owing to this form of the groove and gasket an expansion space is obtained in the gasket groove, but problems arise in retaining the gasket in the groove because the contact surface of the gasket at the walls of the gasket groove are small. Due to that fact the gasket has to be held in the groove by means of special projections.
The aim of the present invention is to solve the problem of gasket expansion and retention in a gasket groove having for instance square, rectangular or dovetailed-formed cross section, and according to the invention there is provided a gasket arrangement as initially described above characterised in that at least one face of the gasket has recesses spaced apart along the gasket whereby the gasket in a non-compressed condition fills the cross sectional area of the groove only at those positions where no recesses have been provided and space for expansion of the gasket is defined in the groove.
Three preferred embodiments of the invention will now be described in detail with reference being made to the accompanying drawings, in which:

Figures 1, 4, 7 are plan views of parts of the gaskets according to the three different embodiments;
Figures 2, 5, 8 are cross sections of the gaskets taken along the lines 11-11, V-V and VIII-VIII of Figures 1,4 and 7, respectively, each gasket being shown in a groove in a heat exchanger plate; and
Figures 3, 6, 9 are cross sections of the gaskets taken along the lines III-III, VI-VI and IX-IX in Figures 1,4 and 7, respectively, each gasket being shown in a groove in a heat exchanger plate.

A first gasket arrangement embodying the invention is disclosed in Figures 1-3. The gasket 1, preferably made of rubber, extends around the periphery of a plate 2 for sealing off the interspace between the plate 2 and an adjacent plate (not shown).
The gasket cross section shown in Figure 2 has essentially the form of a trapezium, with two sides 3, 4 connecting two substantially parallel sides 5, 6.
The gasket 1 is put into a dovetail-formed groove 7 in the heat exchanger plate 2, the side 3 of the gasket co-operating with the flank 9 of the groove 7 and the side 4 of the gasket with the flank 10 of the groove 7 so that the gasket 1 fills up essentially the whole of the cross sectional area of the gasket groove 7. The advantage of this type of groove is that the gasket is held securely in the groove. The disadvantage, however, is that when using a conventional gasket filling up all the space in the groove there is not sufficient expansion space for the rubber.
As can be seen in Figure 1, one side 3 of the gasket 1 has recesses 8 so that the cross section of the gasket at these recesses is reduced as appears from a comparison of Figures 2 and 3. The reduction of the cross section is preferably made in that side 3 of the gasket that does not come into contact with the heat exchanging media.
The recesses 8 are located at certain places along one side 3, 4 of the gasket and preferably recur with even interspaces along the gasket. Recesses, however, can be made in both these sides 3,4 of the gasket 1 which are in contact with the flanks 9, 10 of the gasket groove 7.
Due to the reduction of the cross section there is created space for expansion of the gasket during the tightening of the plate package. Thus, during the tightening of the plate package the recesses become filled up by the expanding rubber. Further, due to the fact that the reduction of the cross section is preferably only made in parts of the one flank of the gasket, the feature of the secure retention provided by the dovetail groove is preserved and at the same time as the sealing features of the gasket are not changed.
In the embodiment of Figurs 4--6 the gasket 11 has an appearance similar to that according to Figures 1-3 with the difference that one of the flanks of the gasket is cut away, whereby the one side 12 of the gasket extends essentially perpendicularly to the bottom surface 13 of the gasket. This side 12 co-operates with a side surface 14 of the gasket groove extending essentially perpendicularly to the plane of the plate 15. The other side 16 of the gasket has such a form that it is in contact with the dovetail-formed flank 17 of the gasket groove. Thus, as shown in Figure 5 the gasket fills essentially the entire cross sectional area of the gasket groove. The gasket 11, like the gasket according to Figures 1-3, has recesses 8, preferably with even interspaces along the gasket, in that side of the gasket that does not come into contact with the heat exchanging media. By these recesses 8 space is created for the expansion of the gasket in the gasket groove.
Due to the fact that the gasket 11 fills up essentially the whole gasket groove cross section along a substantial part of its extension, and that the flank 16 of the gasket is in contact with the dovetail-formed flank 17 of the gasket groove, the gasket is securely held in the gasket groove.
In the embodiment of Figures 7-9 the gasket 18 has a square cross section and co-operates with a gasket groove of a corresponding form. The gasket 18 fills essentially the whole of the cross section of the gasket groove as shown in Figure 8. In order to allow for expansion of the gasket, the gasket is provided with recesses 19, preferably made in that side 20 of the gasket which does not come into contact with the heat exchanging media. These recesses 19 can suitably comprise a square of rectangular cut out from the side 20 of the gasket and recur with even interspaces along the gasket.
Due to the fact that the gasket 18 at the unrecessed places fills up the gasket groove, the gasket is held in the same in a secure way.
The gasket in the third embodiment may have rectangular cross section at the unrecessed places instead of square. Furthermore, it is possible at least in certain applications to have in all three embodiments recesses also in that side of the gasket that is in touch with the heat exchanging media.

Claims

1. A sealing arrangement comprising a groove (7) provided in a plate of a plate heat exchanger, and a gasket (1; 11; 18) of elastic material arranged in said groove, characterised in that at least one face (3; 16; 20) of the gasket has recesses (8; 19) spaced apart along the gasket whereby the gasket (1; 11; 18) in a non-compressed condition fills the cross sectional area of the groove only at those positions where no recesses have been provided and space for expansion of the gasket is defined in the groove.

2. An arrangement according to claim 1, wherein only one side (3; 16; 20) of the gasket (1; 11; 18) contacting a flank (9) of the gasket groove has recesses (8; 19).

3. An arrangement according to claim 2, wherein the side (3; 16; 20) of the gasket (1; 11; 18) provided with recesses (8; 19) does not come into contact with the heat exchanging media.

4. An arrangement according to claim 2 or 3, wherein the recesses (8; 19) are positioned with even interspaces along the side (3; 16; 20) of the gasket.

5. An arrangement according to any one of the preceding claims, wherein the groove is a dovetail groove (7) and the gasket (1) has a cross section (II-II) having substantially the form of a trapezium with the top side (5) smaller than the bottom side (6).

6. An arrangement according to any one of claims 2 to 4, wherein the groove has flanks substantially perpendicular to the plane of the plate, and the gasket (18) at the unrecessed portions has a substantially square cross section.

7. An arrangement according to claim 6, wherein the recesses (19) comprise rectangular cut outs in the side (20) of the gasket.

8. An arrangement according to any one of claims 2 to 4, wherein the gasket groove has one flank (17) which is dovetail-formed and the other flank (14) is substantially perpendicular to the plane of the plate (15).

9. An arrangement according to any one of the preceding claims, wherein the gasket is made of rubber.