Ngk Insulators, Inc.

Institute of Technology Precision Electrical Discharge Work's

Nippon Gaishi Kabushiki Kaishi

Noboru Higuchi

Shoji Futamura

Teruo Yano

Masahiro Ohnishi

Shoji Seike

Takayuki Ogasawara

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 die for extruding a honeycomb structural body, all parts of which are uniform in mechanical strength, is disclosed. The die is provided with guide grooves between discharge slits and feed inlets for raw stock, said discharge slits having a cross-sectional shape corresponding to that of the honeycomb structural body and said guide grooves having a cross-sectional area larger than that of the discharge slits.

Die for extruding a honeycomb structural body and a method of extruding

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.

Method for producing ceramic honeycomb filters

A die for extruding a honeycomb structural body which comprises a throttle portion having a plurality of openings where the forcedly supplied raw stock flow is throttled at the rear surface side of the die, a reservoir portion provided with a plurality of guide channels, an opening portion having a plurality of openings and guide slots, and discharge slits.

Die for extruding a honeycomb structural body

Extrusion dies for extruding honeycomb structural bodies which comprise a plurality of cell blocks having a cross sectional shape conforming to cells of the honeycomb structural body, a spoke supporter, and spokes, one end of which is fixed to the cell blocks and another end of which is integrally secured to the spoke supporter, said adjacent cell blocks forming discharge slits conforming to the cross sectional shape of the honeycomb structure, and said spoke supporter being provided with a plurality of feed inlets having a larger diameter, which are perforated from one end surface of the spoke supporter toward the cell blocks and a plurality of openings having a smaller diameter, which are perforated from another end surface of the spoke supporter to the feed inlet and connect to the feed inlet.

Extrusion dies for extruding honeycomb structural bodies

An insulator with a tin oxide semiconductor glaze coating has a portion at least 100.mu. thick extending from the glaze surface in which the ratio of the maximum to the minimum volume resistivity is not more than 30. It is found that such glazes display marked improvement in resistance to deterioration under unfavorable conditions.

Electrical insulator with semiconductive glaze

A die for extruding a honeycomb structural body capable of preventing the deformation of the honeycomb structural body when the honeycomb structural body is extruded.

Apparatus for extruding a honeycomb structural body

The invention relates to an electrical insulator coated with a semi-conducting tin oxide system glaze layer wherein the glaze layer contains 0.05 to 10 percent by weight of at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, titanium oxide, zirconium oxide, yttrium oxide and tungsten oxide. The additional metal oxide reduces the dependance of resistance on the environmental temperature.

Growing community of inventors

Nagoya, Japan

Noboru Higuchi