摘要:
A honeycomb filter includes an array of interconnecting porous walls which define an array of first channels and second channels. The first channels are bordered on their sides by the second channels and have a larger hydraulic diameter than the second channels. The first channels have a square cross-section, with corners of the first channels having a shape, such as a bevel or fillet, such that the thickness, t3, of the porous walls adjoining the corners of the first channels is comparable to the thickness, t4, of the porous walls adjoining edges of the first and second channels. Embodiments having a corner fillet with a radius, Rc, are also disclosed. Embodiments wherein 0.30 t4≦Rc≦1.0 t4 exhibit combinations of low wall pressure drop and low thermal stress.
摘要:
A honeycomb substrate includes an inner body having an inner skin and an array of inner webs defining an array of inner cells within the inner skin. The honeycomb substrate further includes an outer body having an outer skin formed concentric with the inner skin and an array of outer webs defining an array of triangle cells between the inner skin and the outer skin. The triangle cells are oriented along a radial direction with respect to a center of the inner body. An extrusion assembly for forming the honeycomb substrate includes an inner cell forming die, an outer cell forming die, and a skin forming mask, all mounted coaxially. An outer skin slot formed between the outer cell forming die and the skin forming mask is in communication with feedholes in the inner cell forming die through an opening in the outer cell forming die.
摘要:
A reduced coefficient of thermal expansion and an increased resistance to thermal shock in cordierite-containing ceramic articles is achieved by contacting such articles with water either in a liquid or gaseous state. It is particularly desirable for such treatment to reduce the coefficient of thermal expansion of the article by at least 1.times.10.sup.-7 .degree. C..sup.-1, measured between 25.degree. and 800.degree. C., during the contacting. This treatment can be used in conjunction with extruded honeycomb structures conventionally used as diesel particle filters and supports for catalysts which treat automotive exhaust gases.
摘要:
A rigid mini-monolith structure formed by extrusion from a die. Such structures are useful as catalyst supports for treating exhaust gases from automobile. The structure is in the shape of a right circular cylinder with a plurality of internal cells extending along the substrate and an opening on both ends. In order to provide maximum crushing strength of the structure, as well as permitting uniform intercell wall thickness at the downstream face of the extrusion die which forms the structure, the majority of the cells are formed in the transverse cross section of a truncated (circular) sector and have the property that they each possess the same hydraulic diameter, although not all are of the same transverse cross sectional shape. The invention also is defined by a novel extrusion die formed by a plurality of concentric, collared tubes provided with longitudinally running slots in the tubes and notches on the collars, the tubes being radially spaced from each other. The non-slotted portions of the tubes define the cells of the extruded structure.
摘要:
A honeycomb filter includes an array of interconnecting porous walls which define an array of first channels and second channels. The first channels are bordered on their sides by the second channels and have a larger hydraulic diameter than the second channels. The first channels have a square cross-section, with corners of the first channels having a shape such that the thickness of the porous walls adjoining the corners of the first channels is comparable to the thickness of the porous walls adjoining edges of the first and second channels.
摘要:
A honeycomb extrusion die includes an inlet face having a plurality of feed channels, and a discharge face having an array of intersecting honeycomb discharge slots. The extrusion die also includes a bonded array of pin elements each exposed on the discharge face of the die and juxtaposed to form the discharge slots of the discharge face and the array of feed channels, wherein the discharge slots extend from the feed channels, and wherein the feed channels communicate with the discharge slots so as to guide an extrudable material toward the discharge face. Each pin element includes a plurality of discharge slot surfaces, a plurality of feed channel surfaces continuous with the discharge slot surfaces for guiding the extrudable material toward the discharge face, and a plurality of spacing surfaces for spacing each pin element from adjacent pin elements.
摘要:
A mask apparatus for charging flowable materials into selected cells of a honeycomb structure comprising a solid body having a number of openings extending therethrough which are spaced to coincide with the open ends of the selected cells exposed at the structure's end face, after the mask is positioned across the end face, the flowable material is charged through its openings. In one embodiment, a rigid plate having a number of bores therethrough is provided for charging a plastically formable plugging material into a honeycomb structure in the fabrication of solid particulate filter bodies and other selectively manifolded structures. In a preferred embodiment, a thin transparent polyester film is attached to an open surface of a honeycomb structure and openings melted therethrough. In a second preferred embodiment, a monolithic mask is formed from a flexible elastic polymer and, in addition to openings, has flexible protrusions which assist in aligning the mask on the structure and temporarily plug the cells into which they are inserted preventing them from being inadvertently charged.
摘要:
Honeycomb structures of brittle material having a plurality of cells extending longitudinally therethrough. When viewed in a plane perpendicular to a longitudinal axis through the structure, the plurality of cells extend thereacross and, with the exception of peripheral cells, are all of uniform size and shape. The shape is a rectangle whose length is twice its width. The cells are contiguously arranged in a repeating pattern that provides a "flexible" rectangle cellular structure wherein wall portions and joints formed by intersecting wall portions are movable to compensate for expansion/contraction stresses or forces thermally induced within the cellular structure, thereby tolerating significant strains without breaking the structure.
摘要:
An engine exhaust system is disclosed which in operation is capable of substantially reducing the quantities of hydrocarbons emitted to the atmosphere during engine start-up. The system utilizes molecular sieve means, such as a high-silica zeolite, which function to adsorb hydrocarbons emitted during engine start-up, before the catalytic converter has attained its effective operating temperature. The system is designed so that, once the catalytic converter has attained an effective operating temperature, the hydrocarbons can be desorbed from the molecular sieve means and conveyed to the converter for conversion to non-toxic by-products.
摘要:
This invention is directed at a cross-flow filtration device for receiving a feed stock and for separating the feed stock into filtrate and retentate, comprising a multicellular monolith structure having a central longitudinal axis and a peripheral surface. The monolith structure has both an inlet and outlet end face and a matrix of porous walls which define a plurality of cells; these mutually parallel cells extending longitudinally between the inlet and outlet end faces. The cells exhibit a uniform transverse cross section throughout each respective cell's length and each cell's cross-section and shape is variable when compared to at least one other cell such that all of the cells of the structure exhibit an equivalent hydraulic diameter. Lastly, the monolith structure's cells exhibit an increasing aggregate wall thickness in at least one direction as the cells approach the peripheral surface.