Ngk Insulators, Inc.

Teruo Yano

Noboru Higuchi

Masahiro Ohnishi

The disclosed ceramic honeycomb filter comprises a ceramic honeycomb structural body having a multiplicity of parallel channels extending therethrough, selected channels being sealed at one ends thereof while the remainder of the channels being sealed at opposite ends thereof in such a manner that, as dust-containing gas flows therethrough from said one ends to said opposite ends, the gas passes through walls between adjacent channels where the dust particles are collected. The ceramic honeycomb structural body has a coefficient of thermal expansion .alpha..sub.A of 0 to 8.0.times.10.sup.-6 /.degree.C. for 40.degree. C. to 800.degree. C., and the sealing material of the channels at said ends thereof has a coefficient of thermal expansion .alpha..sub.B which is in the following range for 40.degree. C. to 800.degree. C. The relationship of the coefficients of thermal expansion .alpha..sub.A and .alpha..sub.B are such that .vertline..alpha..sub.A -.alpha..sub.B .vertline..ltoreq.3.5.times.10.sup.-6 /.degree.C., and preferably .vertline..alpha..sub.A -.alpha..sub.B .vertline..ltoreq.2.5.times.10.sup.-6 /.degree.C.

Ceramic honeycomb filter

The disclosed ceramic honeycomb filter comprises a ceramic honeycomb structural body with a multiplicity of parallel channels extending therethrough, selected channels being sealed at one ends thereof by sealing material while the remainder of the channels being sealed at opposite ends thereof by said sealing material in such a manner that, as dust-containing gas flows therethrough from said one ends to said opposite ends, the gas passes through walls between adjacent channels where the dust particles are collected. Said sealing material is alumina cement containing not more than 27% by weight of calcium oxide (CaO), or a mixture of the alumina cement and aggregates.

A ceramic honeycomb filter having a large filter area and a low pressure loss is produced by adhering a film on an opening end surface of a porous ceramic honeycomb structural body having a large number of parallel channels extending therethrough, boring holes at a given portion of the film or adhering a film bored at a given portion to an opening end surface of a porous ceramic honeycomb structural body, charging a sealing material into the channels through the bores in the film to seal an end portion of the given channels, and then sealing another end surface of the remaining channels with the sealing material in the same manner as described above.

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Nagoya, Japan

Teruo Yano