Patent ID: 8286478

Claim:
A flow sensor for sensing a flow of a fluid stream, the flow sensor comprising: a substrate having a top surface; a depression extending into the substrate from the top surface, the depression having an upstream side, a downstream side, a first lateral side and a second lateral side, wherein during use of the flow sensor, the fluid stream flows from the upstream side towards the downstream side; a bridge extending across the depression from the first lateral side of the depression to the second lateral side, the bridge being supported by the substrate adjacent the first lateral side and the second lateral side of the depression, wherein the bridge includes first and second lateral sides extending substantially parallel to a direction of fluid flow, and a leading edge and a spaced trailing edge each extending from the first lateral side to the second lateral side of the depression, the leading edge of the bridge being spaced apart from the upstream side of the depression defining a fluid inlet and the trailing edge of the bridge being spaced apart from the downstream side of the depression defining a fluid outlet; a heater element provided on the bridge; a first sensor element provided on the bridge adjacent an upstream side of the heater element; a second sensor element provided on the bridge adjacent a downstream side of the heater element; and a plurality of apertures extending through the bridge, the plurality of apertures disposed at spaced locations adjacent the first lateral side of the depression along a direction that is substantially parallel to the direction of fluid flow.