Patent ID: 7755466

Claim:
A system comprising: a substrate having a substrate top side and a substrate bottom side; a heating element on the substrate top side; an upstream temperature sensor on the substrate top side, wherein the upstream temperature sensor is positioned upstream of the heating element and is configured to sense a measure related to a first temperature of a fluid passing adjacent the substrate bottom side before the fluid reaches the heating element; a downstream temperature sensor on the substrate top side, wherein the downstream temperature sensor is positioned downstream of the heating element and is configured to sense a measure related to a second temperature of the fluid after the fluid passes the heating element; a channel in the substrate forming at least part of the substrate bottom side under the upstream temperature sensor, the downstream temperature sensor, and the heater, such that a fluid can flow through the channel in a flow direction, a first end of the channel defining a channel inlet, wherein the fluid enters the channel at the inlet; the substrate having a membrane forming a top side of the channel and supporting the upstream temperature sensor, the downstream temperature sensor, and the heater above the channel; a thermal dam that thermally isolates at least part of the membrane from the remainder of the substrate; and an inlet temperature sensor on the substrate top side, upstream of the upstream temperature sensor and adjacent the channel inlet.