| CPC B05B 1/185 (2013.01) [B05B 12/20 (2018.02); B05C 5/027 (2013.01); B05D 1/02 (2013.01)] | 14 Claims |

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1. A method of coating a substrate with a liquid washcoat using a washcoat showerhead;
the washcoat showerhead comprising:
a housing having an inlet;
a showerhead plate; and
a baffle;
the housing and showerhead plate defining a showerhead cavity and the baffle being located within the showerhead cavity;
the showerhead plate comprising a plurality of nozzle apertures;
the baffle comprising an impermeable central body and a plurality of arms extending from the impermeable central body, the plurality of arms defining a plurality of flow apertures circumferentially arranged around the impermeable central body and an upper face of the impermeable central body facing the inlet comprises a protrusion;
the baffle being mounted in the showerhead cavity such that the impermeable central body is spaced from the showerhead plate; and
the impermeable central body being aligned below the inlet of the housing;
wherein the method comprises the steps of:
locating the substrate below the washcoat showerhead;
passing the liquid washcoat through the showerhead cavity from the inlet to the nozzle apertures of the showerhead plate;
discharging the liquid washcoat out of the nozzle apertures towards a face of the filter substrate;
wherein during passage of the washcoat through the showerhead cavity the washcoat is diverted to flow around the impermeable central body of the baffle and through the plurality of flow apertures before being discharged through the nozzle apertures of the showerhead plate.
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