Apparatus and method for coating substrates with washcoats

A method of coating a substrate with a washcoat using a substrate coating apparatus;

• the substrate coating apparatus being of the type comprising:
• a source of a washcoat;
• a washcoat showerhead comprising a showerhead plate having a plurality of nozzle apertures;
• a conduit fluidly connecting the source of the washcoat to the washcoat showerhead;
• and
• a partition ring located between the washcoat showerhead and a face of the substrate;
• wherein the method comprises the steps of:
• locating the substrate below the washcoat showerhead;
• bringing the partition ring into contact with the face of the substrate to thereby define a central region of the face of the substrate which lies within an interior of the partition ring and a peripheral region of the face of the substrate which lies outside the partition ring;
• conveying washcoat from the source of the washcoat, along the conduit and through the washcoat showerhead;
• discharging the washcoat out of the nozzle apertures towards the face of the substrate, the showerhead plate of the washcoat showerhead discharging washcoat onto both the central region and the peripheral region of the face of the substrate.