GB1484124A - Heat exchangers - Google Patents

Abstract

1484124 Plate heat exchangers ASSOCIATED ENG Ltd 21 Nov 1974 [31 Aug 1973] 41216/73 Heading F4S [Also in Division B3] A heat exchanger matrix comprises a series of contiguous, apertured, metal, plate elements, with together define one or more fluid flow passages, diffusion bonded together. A matrix 1 for a water cooled oil cooler, in one embodiment, comprises copper plates 5 arranged alternately with copper plates 6, the plates 5 having slots 5a and rows of apertures 5b and the plates 6 having slots 6a similar to the slots 5a and wider slots 6b. The assembly is solid state diffusion bonded together and end manifolds 2, 3 having channels 7, 8 and connecting ports 9, 10 are connected to the matrix, by diffusion bonding if made of copper or by adhesive bonding, soldering or brazing or mechanical fixing if of a different metal. In use the ports 9 are for oil to be cooled and the ports 10 for cooling water. In the heat exchanger the oil flows through the passages formed by apertures 5b and slots 6b, and the cooling water flows through the passages defined by apertures 5a and slots 6a. In another embodiment copper plates each with a large rectangular aperture are arranged alternately with copper plates each having three apertures and assembly is solid phase diffusion bonded. The end manifolds are secured by diffusion bonding or otherwise and oil only is passed through the cooler which is is arranged in a water hose. The large aperture may alternatively be divided into two and the inlet and outlet connections are then provided in one manifold, the other merely connecting the passages. The copper plates are provided with a commercially available finish of 20-50 micro inches CLA, are cleaned and degreased, possibly preheated by induction, and are heated at 700‹ C. for 30 minutes under a load of 1À3 ton per square inch in an atomosphere of cracked ammonia. The load may be applied by a jig having end plates 31, Fig. 3a connected by pillars 33 one plate 31 being loaded by springs 32. The jig is of material having a coefficient of expansion similar to that of the matrix. The pressure may be applied by nuts acting directly on the upper end plate when the pillars have a lower thermal expansion than the matrix. The end plates may alternatively have a higher expansion coefficient than the matrix. Stainless steel, nickel or nickel alloys may be the metals of the parts to be joined.