Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Secondary discharge slots are cut into the face of newly made or used extrusion dies such that the secondary discharge slots communicate transversely and longitudinally with primary discharge slots but do not communicate with the feed holes. The novel extrusion die arrangement is set forth for the production of ceramic honeycomb structures which produce a greater number of cells per square inch, protrusions on the cell walls, or a combination of both dependent upon the Primary Slots' Volume to Secondary Slots' volume ratio. The secondary discharge slots can produce honeycomb substrates with much greater surface areas, using an extrusion die with a significantly reduced number of feed holes and a greater number of discharge slots.

Abstract: An extrusion die is used for producing ceramic honeycomb materials. It is particularly useful in producing such extrudates in sheet form by configuring the die in the form of a cylinder and providing a cutting device proximate to the exterior of the cylinder so that when relative rotation is imparted between the cutter and the cylinder, a honeycomb sheet is removed. A cover can be provided over the exterior surface of the cylindrically-shaped die to permit formation of honeycomb extrudates in pellet form.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Secondary discharge slots are cut into the face of newly made or used extrusion dies such that the secondary discharge slots communicate transversely and longitudinally with primary discharge slots but do not communicate with the feed holes. The novel extrusion die arrangement is set forth for the production of ceramic honeycomb structures which produce a greater number of cells per square inch, protrusions on the cell walls, or a combination of both dependent upon the Primary Slots' Volume to Secondary Slots' Volume ratio. The secondary discharge slots can produce honeycomb substrates with much greater surface areas, using an extrusion die with a significantly reduced number of feed holes and a greater number of discharge slots.

Abstract: 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.

Abstract: An apparatus for filtering solid particulates from fluid flows having a honeycomb filter body formed by a matrix of thin, interconnected porous walls which define inlet and outlet faces of the body and a plurality of hollow inlet and outlet cells each extending through the body from at least one of the inlet or outlet faces, the thin walls having internal interconnected open porosity sufficient to allow the fluid to travel completely across the thin walls in their narrower dimension and through the thin walls in their longer dimensions between the inlet and outlet cells and to prevent at least a significant portion of the solid particulate material carried by the fluid from passing either completely across or through the walls. Solid particulate filtering occurs on all thin wall surfaces of the inlet cells regardless of whether those thin walls are shared with adjoining inlet or outlet cells.

Abstract: Filtering capacity of a honeycomb filter having a plurality of cells formed by a matrix of thin, porous intersecting walls and used for removing solid particulates mixed in fluids is improved by providing a porous outer wall around the thin walls through which the fluid is also filtered. A particulate barrier is provided between the outer wall and a conduit carrying the contaminated fluid to and filtered fluid from the filter which allows the fluid to flow along and through a substantial portion of the porous outer surface of the filter while preventing contaminated fluid from bypassing the filter. The barrier is preferably formed near an inlet or an outlet end face of the filter and those cells which are located around the periphery of the end faces are preferably open at that same end face and closed at the remaining end face to assure fluid flow across the porous outer wall.

Abstract: A diesel particulate filter for removing particulates from the exhaust gases of smaller displacement light duty vehicle diesel engines (about 3.0 liters or less cylinder displacement or more refined larger engines) which typically generate particulates at an average rate of about 0.45 gm./mile or less in a normal driving cycle comprising a honeycomb structure formed by a matrix of thin interconnected porous walls defining a multiplicity of cells extending, in preferred embodiments, in a substantially longitudinal and mutually parallel fashion through the filter. An inlet group of the cells is open at and define an inlet open end face of the filter. An outlet group of the cells is open at and define an outlet end face of the filter. The inlet cells are closed adjacent to the outlet end face and the outlet cells are closed adjacent to inlet end face.

Abstract: The resistance of a honeycombed structure to damage from asymmetric thermal shock occurring across its surface during use and formed with cells having anisotropic Young's moduli in the planes perpendicular the central longitudinal axis of each cell can be improved by varying the orientation of the anisotropic cells with respect to one another so as to minimize the number of such cells being oriented with an axis of maximum Young's moduli aligned with the direction of either the maximum temperature difference or maximum localized temperature gradient occurring across the cell.

Abstract: The thermal shock resistance of a honeycombed structure or a structure having a honeycombed surface formed by bonding together a plurality of cellular segments each having a honeycombed face forming a portion of the structure or surface of the structure, respectively, is improved by recessing the bond joints between the joined cellular segments from the surface. The thermal shock resistance of a heat recovery wheel operated in a counterflow heat exchanger system and formed from joined cellular segments is improved by recessing the bond joints joining the cellular segments, preferably approximately one-half inch (12.7 mm), from the face of the wheel exposed to the gases at their highest temperatures.