Method and apparatus for coating a carrier

A method for coating a plurality of carrier bodies comprising flow ducts or flow pores, the method comprising, for each carrier body in a production run:

• (a) weighing said carrier body to determine the weight of the uncoated carrier body;
• (b) delivering a coating suspension to the carrier body;
• (c) removing surplus coating suspension from said carrier body by pumping or suction to leave a quantity of wet coating suspension on the carrier body in the form of a raw coating that is present in a quantity greater than a desired target quantity for the carrier body;
• (d) weighing said carrier body, after step (c) and prior to any further removal of coating suspension from the carrier body, to determine the weight of said raw coated carrier body;
• (e) determining a differential quantity which is the difference between the quantity of raw coating on said carrier body and the desired target quantity of coating on said carrier body;
• and
• (f) reducing the difference between the raw coating quantity and the desired target quantity by applying suction or pressure to still wet raw coating on the carrier body at an intensity, a duration, or both an intensity and a duration that is based on the magnitude of the differential quantity determined following weighing of the raw coated carrier body,
• wherein the delivery step (b) and removal step (c) together yield, on average for the plurality of the carrier bodies coated, an overloaded raw coating comprising a wet coating suspension that is not less than 102% of the target quantity and not more than 105% of the target quantity, the amount of the overloaded raw coating being set to correspond to the sum of the target quantity plus a variation amount of the wet coating quantity applied among carrier bodies coated in the production run coating operation.

A method for coating a plurality of carrier bodies, comprising flow ducts or flow pores, with at least one coating suspension, wherein the coating suspension comprises solids in a liquid medium, in a quantity in wet state that corresponds to at least a required target quantity, and the coating operation includes a variation in the applied wet coating quantity from one body to the other, the method comprising, for each carrier body in a production run:

• (a) placing a raw coating onto a carrier body at a coating station by
• (i) delivering a quantity of the coating suspension to the flow ducts or tow pores of the body;
• and
• (ii) removing an amount of surplus coating suspension by pumping or suction to leave a quantity of wet coating suspension on the carrier body in the form of a raw coating the raw coating being present in a quantity that is larger than the required target quantity;
• (b) determining, after step (a)(ii) and prior to any further removal of coating suspension from the body, the difference between a quantity of raw coating on the carrier body and the required target quantity for the carrier body comprising weighing the carrier body after a coating step,
• (c) reducing the difference between a weighed quantity of raw coating and the target quantity on that carrier body by removing still wet coating suspension from the weighed carrier body by a suction or pressure application based on the determination made in step (b),
• (d) repeating steps (a) to (c) for each of the plurality of carrier bodies;
• and
• wherein the raw coating step (a) yields, on average for the plurality of the carrier bodies coated, an overloaded raw coating comprising a wet coating suspension that is not less than 102% of the target quantity and not more than 105% of the target quantity, the amount of the overloaded raw coating being set to correspond to the sum of the target quantity plus the variation amount of the coating operation,
• wherein the solids of the coating suspension comprises a support material and the liquid medium of the coating suspension comprises water, with the solids having a concentration between 20 and 65 wt.-% based on the total weight of the coating suspension,
• wherein for each of the repeated steps (c) in step (d) there is carried out individualized difference reduction removal of still wet coating suspension if the determined difference for a respective carrier body in the production run exceeds a threshold value, wherein
• each individualized difference reduction removal step comprises an individualized coating suspension removal level adjustment in the suction or pressure application, and
• there is referenced, for each carrier body subjected to a respective individualized difference reduction, data informative of a predetermined association between a required individualized coating suspension removal level adjustment amount for the suction or pressure application that is needed for achieving reduction of the determined difference between the quantity of raw coating on the carrier body and the target quantity for that respective carrier body.