GB1581979A - Plate heat exchangers - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO PLATE HEAT EXCHANGERS (71) We, THE A.P.V. COMPANY LIMI TED, a British Company, of Manor Royal, Crawley, Sussex, 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:: This invention relates to plate heat ex changes of the type comprising a separable pack of plates arranged in spaced face to face relationship to define flow spaces between the adjacent plates, the plates having aligned holes to form ports extending through the pack for the supply and discharge of heat exchange media flowing through the flow spaces, and gasket ing defining and sealing the peripheries of the flow spaces and controlling the com munication between the ports and the flow spaces.

Such plate heat exchangers are well known and will be referred to hereinafter as plate heat exchangers of the type described.

The gaskets of plate heat exchangers are normally of elastomer material to provide an adequate degree of compressibility for sealing and also chemical resistance to the media in the exchanger.

Elastomeric materials for gaskets which are suitable for certain aggressive liquids, such as some organic solvents, are much more expensive than those which are capable of resisting aqueous liquids only. If a plate heat exchanger is designed to handle these different liquids it is normal practice to fit the expensive resistant gaskets throughout the machine.

This overlooks the fact that the- difficult liquid is frequently heated or cooled by a service liquid of an aqueous nature for, which the expensive gasket is unnecessary, and it is proposed, according to the pre sent invention, to provide a cheaper arrangement by using the expensive gaskets only on the plates carrying the aggressive liquids and cheaper gaskets on the plates carrying the aqueous liquids.

Accordingly, the present invention consists in a plate heat exchanger of the type described, in which gasketing in contact with one of the heat exchange media is of one elastomer material, whereas gasketing solely in contact with another heat exchanger medium is of another elastomer material.

It will be appreciated that on any given plate, the peripheral gasket defining the flow-spaces will be of one material while the gaskets sealing the transfer ports between flow spaces carrying the same liquid will be of the other material. In order to prevent a mis-match, i.e. use of the same gasket material for both functions, means may be provided on the gaskets to prevent their assembly together on the same plates in the same material.

The invention will be further described with reference to the accompanying drawings, which illustrate diagrammatically a preferred embodiment of the invention, and in which: Figure 1 is a side elevation of a typical plate heat exchanger of the type described; Figure 2 is an elevation of a typical heat exchanger plate for use in such an exchanger; Figure 3 is a view illustrating the gasket formation on alternate plates in a preferred embodiment of plate heat exchanger according to the -present invention; and Figure 4 illustrates the gasket formations on the intervening plates.

Referring first to Figure 1, a typical heat exchanger is shown and consists of a pack of plates 1 suspended on a top rail 2 and located by a bottom rail 3 extending between a head 4 and an end support 5. The plates 1' are compressed between the head 4 and a follower 6 which is movable along the top and bottom rails 2 and 3, and a pack of plates is retained in compressed condition by suitably constraining the follower 6. In the present case, tie bars 7 are illustrated for this purpose.

The head 4 is shown as having liquid connections 8, which are normally four in number so as to align with ports 9 (see Figure 2) formed by aligned holes near the corners of the generally rectangular plates 1. In the case of a single pass heat exchanger, there will be no connections 8 on the follower 6, but where a multi-pass arrangement is used, further connections will have to be provided on the follower.

Figure 2 shows a typical plate in diagrammatic form, and there is shown a hanging eye 10 for cooperation with the top rail 2 and a recess 11 which fits over the bottom rail 3 to stabilise the plate. The plate is also provided with grooves for gaskets so as to accommodate a peripheral gasket which bounds the flow space 12 and leaves it in communication with two of the flow ports 9a. In addition, there are grooves for gaskets to isolate the two transfer ports 9b from the flow space 12.

It will be appreciated that the peripheral gasket will be in contact with only one heat exchange medium, while the two transfer port gaskets on the plates will be in contact with the other heat exchange medium, and by providing dead spaces 13 which are normally sealed from both media, it can be arranged that neither form of gasket is in contact with both media.

Figure 3 shows a gasket arrangement for a plate which is of the same hand as the plate illustrated in Figure 2, and it will be seen that the peripheral gasket 15 is shown in broken line to indicate that it is of one material, in accordance with the teaching of the present invention, while the transfer port gaskets 16 are shown in full lines to indicate that they are of another elastomeric material. Figure 4 shows a plate of the opposite hand which has its flow space communicating with the other two ports 9 and in this case the peripheral gasket 15a is of the said other material while the transfer port gasket 16a are of the first material. In this manner, one material may be especially chosen for one medium while the other is more suitable for the other.

In respect of an aqueous medium such as is normally used for heating or cooling, the special choice may be on grounds of cost rather than chemical resistance.which is probably the most likely criterion on which a more expensive gasket would be ch-sen.

In order to prevent mis-matching of a gasket 15 with gaskets 16a of the same material which would mean that the same gasket material would be in contact with both media, it is made impossible to assemble these gaskets together without mechanical interference the one with the other. This is achieved by the provision of extension pieces 17 on the gasket 15 which would foul corresponding extensions 18 on the gaskets 16a, and providing corresponding extensions 19 on the gaskets 15a and 21 on the gaskets 16, which also would foul in the case of an mis-match. It will be seen that with directly matched gaskets 15 and 16 or 15a and 16a, no such fouling or mechanical interference will occur.

Various modifications may be made within the scope of the invention.

WHAT WE CLAIM IS: - 1. A plate heat exchanger of the type described in which gasketing in contact with one of the heat exchange media is of one elastomer material, whereas gasketing solely in contact with another heat exchange medium is of another elastomer material.

2. A plate heat exchanger as claimed in claim 1, in which each individual plate is provided with a peripheral gasket and a transfer port gasket which are of different materials and in which means is provided on the gaskets to prevent assembly on to a single plate of a peripheral gasket and a transfer port gasket of the same material.

3. A plate heat exchanger as claimed in claim 2, in which the said means com- prises extension pieces on the gaskets which mechanically interfere with one another when gaskets of the same material are assembled on a single plate but which do not interfere when the gaskets are correctly assembled.

4. A plate heat exchanger as claimed in claim 1 as hereinbefore described with reference to the accompanying drawing.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. number so as to align with ports 9 (see Figure 2) formed by aligned holes near the corners of the generally rectangular plates 1. In the case of a single pass heat exchanger, there will be no connections 8 on the follower 6, but where a multi-pass arrangement is used, further connections will have to be provided on the follower. Figure 2 shows a typical plate in diagrammatic form, and there is shown a hanging eye 10 for cooperation with the top rail 2 and a recess 11 which fits over the bottom rail 3 to stabilise the plate. The plate is also provided with grooves for gaskets so as to accommodate a peripheral gasket which bounds the flow space 12 and leaves it in communication with two of the flow ports 9a. In addition, there are grooves for gaskets to isolate the two transfer ports 9b from the flow space 12. It will be appreciated that the peripheral gasket will be in contact with only one heat exchange medium, while the two transfer port gaskets on the plates will be in contact with the other heat exchange medium, and by providing dead spaces 13 which are normally sealed from both media, it can be arranged that neither form of gasket is in contact with both media. Figure 3 shows a gasket arrangement for a plate which is of the same hand as the plate illustrated in Figure 2, and it will be seen that the peripheral gasket 15 is shown in broken line to indicate that it is of one material, in accordance with the teaching of the present invention, while the transfer port gaskets 16 are shown in full lines to indicate that they are of another elastomeric material. Figure 4 shows a plate of the opposite hand which has its flow space communicating with the other two ports 9 and in this case the peripheral gasket 15a is of the said other material while the transfer port gasket 16a are of the first material. In this manner, one material may be especially chosen for one medium while the other is more suitable for the other. In respect of an aqueous medium such as is normally used for heating or cooling, the special choice may be on grounds of cost rather than chemical resistance.which is probably the most likely criterion on which a more expensive gasket would be ch-sen. In order to prevent mis-matching of a gasket 15 with gaskets 16a of the same material which would mean that the same gasket material would be in contact with both media, it is made impossible to assemble these gaskets together without mechanical interference the one with the other. This is achieved by the provision of extension pieces 17 on the gasket 15 which would foul corresponding extensions 18 on the gaskets 16a, and providing corresponding extensions 19 on the gaskets 15a and 21 on the gaskets 16, which also would foul in the case of an mis-match. It will be seen that with directly matched gaskets 15 and 16 or 15a and 16a, no such fouling or mechanical interference will occur. Various modifications may be made within the scope of the invention. WHAT WE CLAIM IS: -

1. A plate heat exchanger of the type described in which gasketing in contact with one of the heat exchange media is of one elastomer material, whereas gasketing solely in contact with another heat exchange medium is of another elastomer material.

2. A plate heat exchanger as claimed in claim 1, in which each individual plate is provided with a peripheral gasket and a transfer port gasket which are of different materials and in which means is provided on the gaskets to prevent assembly on to a single plate of a peripheral gasket and a transfer port gasket of the same material.

3. A plate heat exchanger as claimed in claim 2, in which the said means com- prises extension pieces on the gaskets which mechanically interfere with one another when gaskets of the same material are assembled on a single plate but which do not interfere when the gaskets are correctly assembled.

4. A plate heat exchanger as claimed in claim 1 as hereinbefore described with reference to the accompanying drawing.