Apparatus and method for coating substrates with washcoats
The disclosure relates to a substrate coating apparatus that comprises a source of a washcoat; a washcoat showerhead for discharging the washcoat towards an upper surface of a substrate; a conduit fluidly connecting the source of the washcoat to the washcoat showerhead for supplying washcoat to the washcoat showerhead; a headset for engaging the substrate to locate the upper surface of the substrate below the washcoat showerhead; and a vacuum generator for drawing the washcoat discharged from the washcoat showerhead through the substrate. The headset comprises a partition comprising a plurality of holes, the partition being located in between the washcoat showerhead and the upper surface of the substrate when the substrate is engaged in the headset so as to maintain a first gap between a lower face of the partition and the upper surface of the substrate.
1. A substrate coating apparatus comprising:
a source of a washcoat;
a washcoat showerhead for discharging the washcoat towards an upper surface of a substrate;
a conduit fluidly connecting the source of the washcoat to the washcoat showerhead for supplying washcoat to the washcoat showerhead;
a headset for engaging the substrate to locate the upper surface of the substrate below the washcoat showerhead; and
a vacuum generator for drawing the washcoat discharged from the washcoat showerhead through the substrate;
wherein the headset comprises a partition comprising a plurality of holes, the partition being located in between the washcoat showerhead and the upper surface of the substrate when the substrate is engaged in the headset so as to maintain a first gap between a lower face of the partition and the upper surface of the substrate.
2. The substrate coating apparatus according to claim 1 , wherein the partition is fixedly located in the headset so as to be held stationary relative to a housing of the headset.
3. The substrate coating apparatus according to claim 1 , wherein the first gap is between 2 and 7 mm.
4. The substrate coating apparatus according to claim 1 , wherein the percentage open area of the partition, defined as the percentage of the total area of the upper face of the partition that is comprised by the holes, is between 35 and 55%.
5. The substrate coating apparatus according to claim 1 , wherein the percentage open area of the partition, defined as the percentage of the total area of the upper face of the partition that is comprised by the holes, is between 40 and 50%.
6. The substrate coating apparatus according to claim 1 , wherein the headset further comprises a headset seal and the partition is arranged in the headset above the headset seal.
7. A substrate coating system comprising the substrate coating apparatus of claim 1 and a substrate, wherein the upper surface of the substrate is non-planar; and wherein the upper surface of the substrate comprises a groove or cut-out, which extends to the sidewall of the substrate thereby defining a gap in the sidewall.