Abstract: A method for controlling the coating with alumina of ceramic monolithic catalyst supports on a production basis to achieve repeatability of coating utilizing a vacuum system to distribute a coating slurry of alumina over the interior surfaces of and purge the excess coating slurry from the support at the same time that plugged tubular passageways through the support are unplugged, comprising the steps of applying the coating slurry to the support which has at least about 100 axially aligned tubular passageways to the square inch and subjecting the support to a vacuum to draw the slurry through the passageways and remove plugging and excess slurry to form a coating of alumina on the passageway surfaces. The support is dried and calcined to fix the alumina coating on the passageway surfaces.

Abstract: A method for controlling the coating of ceramic monolithic catalyst supports on a production basis to achieve repeatability of coating utilizing a vacuum system to distribute the coating slurry over the interior surfaces of and purge the excess coating slurry from the support at the same time that plugged tubular passageways through the support are unplugged, comprising the steps of applying the coating slurry to the support and subjecting the support to a vacuum to draw the slurry through the passageways and remove plugging and excess slurry to form a coating on the passageway surfaces. Apparatus for practicing the method is adapted to either dipping the support in the slurry or charging the slurry to the support at its upper end as positioned in the apparatus.