Vapour delivery apparatus

A method of operating a vapour delivery apparatus, the vapour delivery apparatus comprising:

• an air passage defined between an air inlet and an outlet;
• a vapour generator arranged in the air passage, wherein the vapour generator comprises a substrate loaded with a source of an active ingredient for generation of the vapour,
• the vapour generator comprising a constricted air flow region, the constricted air flow region being bounded on at least one side by the substrate;
• wherein the constricted air flow region comprises multiple bores through the substrate,
• each bore of the multiple bores configured to enable air to travel from the air inlet to the outlet;
• wherein the method comprises the steps of:
• the user inhaling at the outlet to generate an air flow, wherein an air flow velocity in the constricted air flow region is higher than the air flow velocity in the air passage upstream of the vapour generator for a given air flow rate from the air inlet to the outlet;
• and
• the user receiving the active ingredient from extraction of a vapour from the substrate into the air flow in the constricted air flow region.