STRUCTURE FOR A FILTER OR A HEAT EXCHANGER AND A METHOD FOR MAKING THE STRUCTURE

A structure (10 or 100) useful for separating contaminants from fluids or exchanging heat between two fluids includes a fused single crystal acicular ceramic support (12 or 112) having a discriminating layer (38 or 128) disposed on at leat part of the support. The support has at least one channel that extends entirely through the body. If the structure is used as a filter, the discriminating layer is suitably a sintered, porous alpha-alumina membrane or other porous membrane. If the structure is used as a heat exchanger, the discriminating layer is impermeable. The support is preferably composed of a non-stoichiometric acicular mullite. The support may be in either a dead-end or cross-flow configuration. The structure may include plugs (22 and 23) to close off one end or the other of the channels in the support. The structure preferably includes end caps (118) over the ends of the support. The end caps should be of the same ceramic as used in the support. The ceramic material used in the support, plugs and end caps is interlocked, thereby connecting the plugs and end caps to the support. The filter is preferably covered by a fired, enamel glaze on the outside of the support and the end caps. A method for making the filter includes the step of converting a green ceramic support in situ into acicular ceramic particles, preferably into whiskers. The method preferably entails affixing the support, plugs and end caps together by interlocking them by the conversion step. Une structure (10 ou 100) utile pour la séparation d'éléments contaminants de fluide ou pour l'échange de chaleur entre deux fluides comprend un support céramique aciculaire monocristal fusionné (12 ou 112) ayant une couche distinctive (38 ou 128) disposée sur au moins une partie du support. Le support possède au moins un canal qui s'étend entièrement à travers le corps. Si la structure est utilisée comme filtre, la couche distinctive est avantageusement une membrane d'alphar-alumine frittée, poreuse ou une autre membrane poreuse. Si la structure est utilisée comme échangeur de chaleur, la couche distinctive est imperméable. Le support se compose de préférence de mullite aciculaire non stoechiométrique. Le support peut avoir une configuration en cul-de-sac ou une configuration à écoulement transversal. La structure peut comprendre des bouchons (22 et 23) pour fermer une extrémité ou l'autre des canaux du support. La structure comprend de préférence des chapeaux (118) sur les extrémités du supppo