Contactless leveling of a washcoat suspension
AssigneeUmicore AG & Co. KG
InventorsJuergen Koch, Astrid Mueller
Life of this patent
Estimating the term…
Abstract
A process for coating substrates of motor vehicle exhaust gas catalysts is described, and includes steps of applying a suspension (e.g., washcoat) to a substrate, allowing a shear force to act on the applied washcoat, as in pressure transmitted by gas (e.g., air), and then sucking and/or pressing the washcoat into the substrate. The process in inclusive of providing the suspension (washcoat) containing the catalytic material from above in a metered charge process. An apparatus for carrying out the noted process steps is also featured.
Claims19
A process for coating a substrate monolith of the flow-through or wall-flow type with a washcoat suspension, characterized in that
- the washcoat suspension is applied from above to one end of an upright substrate monolith in a first step,
- a shear force in the form of pressure transmitted by gas is allowed in a subsequent step to act on a surface of the washcoat suspension in order to level it in a contactless manner, and
- the washcoat suspension is subsequently sucked into and/or pressed into the substrate monolith, and wherein the washcoat suspension provided to the one end of the upright substrate monolith in the first step has a thickness of 0.5-15 cm prior to the washcoat suspension being sucked into and/or pressed into the substrate monolith, and wherein the shear force, which is directed into the thickness of the washcoat suspension provided to the one end of the upright substrate monolith in the first step, is applied only to a region of the thickness of the washcoat suspension and not to the entire thickness of the washcoat suspension.
A process for coating a substrate monolith of the flow-through or wall- flow type with a washcoat suspension, characterized in that
- the washcoat suspension is applied from above to one end of an upright substrate monolith in a first step,
- a shear force in the form of pressure transmitted by gas is allowed in a subsequent step to act on a surface of the washcoat suspension in order to level it in a contactless manner, and
- the washcoat suspension is subsequently sucked into and/or pressed into the substrate monolith, and
- wherein the washcoat suspension provided to the one end of the upright substrate monolith in the first step has a thickness of 0.5-15 cm prior to the washcoat suspension being sucked into and/or pressed into the substrate monolith, and
- wherein the washcoat suspension has a viscosity of 0.1 to 50 Pa*s, and
- wherein the shear force is greater than the flow limit of the surface of the washcoat suspension having the viscosity of 0.1 to 50 Pa*s as to put the surface of the washcoat suspension into a flowable state as to enable removal of irregularities in the surface of the washcoat suspension,
- wherein the pressure transmitted by gas on the washcoat suspension is reduced continuously or stepwise during a duration of the transmitting, and
- wherein the pressure transmitted on the washcoat suspension is reduced continuously or stepwise during a duration of the transmitting by one or both of a height variation in a source of the pressure transmitted or a reduction in air pressure or resonator power generated by the source of the pressure transmitted by gas.
A process for coating a substrate monolith of the flow-through or wall- flow type with a washcoat suspension, characterized in that
- the washcoat suspension is applied from above to one end of an upright substrate monolith in a first step,
- a shear force in the form of pressure transmitted by gas is allowed in a subsequent step to act on a surface of the washcoat suspension in order to level it in a contactless manner, and
- the washcoat suspension is subsequently sucked into and/or pressed into the substrate monolith, and
- wherein the washcoat suspension provided to the one end of the upright substrate monolith in the first step has a thickness of 0.5-15 cm prior to the washcoat suspension being sucked into and/or pressed into the substrate monolith, and
- wherein the washcoat suspension has a viscosity of 0.1 to 50 Pa*s, and wherein the shear force is greater than the flow limit of the surface of the washcoat suspension having the viscosity of 0.1 to 50 Pa*s as to put the surface of the washcoat suspension into a flowable state as to enable removal of irregularities in the surface of the washcoat suspension,
- wherein the pressure transmitted is generated by a pulsating gas/air stream from a sound- or pressure-wave generator, and wherein the sound- or pressure-wave generator is lifted in height away from the substrate monolith while still in operation.
A Process process for coating a substrate monolith of the flow-through or wall-flow type with a washcoat suspension, characterized in that
- the washcoat suspension is applied from above to one end of an upright substrate monolith in a first step,
- a shear force in the form of pressure transmitted by gas is allowed in a subsequent step to act on a surface of the washcoat suspension in order to level it in a contactless manner, and
- the washcoat suspension is subsequently sucked into and/or pressed into the substrate monolith, and wherein the washcoat suspension provided to the one end of the upright substrate monolith in the first step has a thickness of 0.5-15 cm prior to the washcoat suspension being sucked into and/or pressed into the substrate monolith, wherein the pressure transmitted is generated by a gas/air stream from an air nozzle, and wherein, upon initiation of washcoat suspension flow, the air nozzle is lifted away from the substrate monolith while still in operation.
Dependencies are inferred from the claim text.