AN ENDLESS PLATE HEAT EXCHANGER RUBBER-GASKET

Abstract: An endless rubber packing for plate heat exchangers to be inserted between the plates as known in the art, characterized in that a sleeve (6) of a for the heat exchanger media unpenetratable metal material is provided at least along one side of the packing (4) across the packing plane.

Description: An endless Plate Heat Exchanger Rubber Gasket The present invention relates to an endless plate heat exchanger rubber gasket, especially to be inserted between the plates as known in the art around its ports. In plate heat exchangers the packings and the packing material are considered to be the plate heat exchangers more critical components. The chemical composition of the rubber used as packing makes the rubber to age in different ways depending on the temperature and the media the heat exchanger has to operate in. Oil for instance makes the rubber to swell, the sealing force then increasing with resulting cracks, if not the right material is used. When for instance ammonium hydrate is used in the plate heat exchanger a certain mass transport of it is achieved through the packing material itself. Different types of packing materials have to be used for ammonium hydrate in combination with oil and for ammonium hydrate without any oil. The choice of packing is always a compromise. In trying to eliminate these drawbacks and to increase the lifetimer of the packing the invention has been proposed in accordance with the claims characterizing parts. The invention will be described in detail with examples with reference to the drawing, where Ωgure 1 schematically shows a corner of the heat exchanger with packings, figure 2 shows two assembled heat exchanger plates, figures 3 and 4 show various embodiments of the invention and figure 5 shows a further detail of an embodiment of the invention. The plate heat exchanger consists in the usual way of a number of plate elements, the short side of such an element being shown in figure 1 with the packing 1 sealing peripherically, the medium said to be harmless. Around two port holes on the plate the endless packings 2 are installed sealing the medium with a tendency for diffusion. Hitherto this is known plate heat exchanger technology and will therefore not been discussed in detail. Figure 2 shows a partial section of two assembled plates 3 in their packing groove portion and the there situated packing 4. In the shown example the packing consists of an O-ring packing situated around two of the plate element ports. It is assumed that one of the heat exchanger media, e.g. ammonium hydrate, is situated on the drawing to the right of the packing, i.e. the pressure on the packing acts from this side. Figure 3 shows a packing according to the invention. The packing of the example is an O-ring packing, where on its outside, i.e. the side of the packing situated across the packing plane, a sleeve is fastened in form of a metal ring of an alloy conveniently selected depending of the for the heat exchanger proper substance diffusing through the packing. The sleeve circumsizes the packing cross section to such an extent that the sleeve, when pressing the packing during assembly between the heat exchanger plates, will come into contavt with the packing groove plate material. This is illustrated in figure 2 with the packing 4 by means of compression pressing the sleeve 6 against the packing groove edges and the sleeve thus sealing against these, and any diffusion through it will thus be stopped at the sleeve 6 and therefore not be leaking any further. Figure 4 shows an O-ring packing provided with a sleeve 6 both on the outside and on the inside. Here it is only the packing pressing the inside sleeve 6 against the packing groove material. However, in the case of the ouside sleeve 6, the sealing force is effected also by the hydrostatic pressure between the heat exchanger plates. Figure 5 shows a partial section of a sleeve 6 provided with a sealing lip 7 along each outside edge, of which only one is illustrated. During assembly according to figure 2 this sealing lip in cooperation with the packing groove material will contribute to an effective sealing effect. The sleeve can be fixed to the packing in different ways, e.g. by means of glueing or vulcanizing or simply hooking to the packing, if this is an O-ring packing. Moreover it is understood that the invention might be adapted to other types of packings and that the invention is not limited to an O-ring packing or any packing profile.

Claims: CLAIMS 1. An endless rubber packing for plate heat exchangers to be inserted between the plates as known in the art around its ports, characterized in that a sleeve (6) of a for the heat exchanger media unpenetrable metal material is provided at least along one side of the packing (4) across the packing plane and in a cross section has a concave form partly circumsizing the packing side or sides. 2. An endless rubber packing according to claim 1, characterized in that the sleeve (6) at its outside edges comprises formed lips (7). 3. An endless rubber packing according to any of the preceding claims, characterized in that the packing is an O-ring packing.

Inventors: LINDAHL LARS, LINDAHL, LARS
Applicants: LINDAHL LARS, SWEP INTERNATIONAL AB, LINDAHL, LARS
Application year: 1997
Main classification: F28F3
IPC codes: F16J15, F28F3