Abstract: A sensor apparatus includes a heating element comprising an upstream side and a downstream side. A first heat sensing set is generally configured adjacent to the upstream side of the heating element and comprises a first sensing element and a second sensing element, the first and second sensing elements configured in a serpentine, interdigitated pattern. A second heat sensing set can be configured adjacent to the downstream side of the heating element and comprises a third sensing element and a fourth sensing element, the third and fourth sensing elements configured in a serpentine, interdigitated pattern.

Abstract: A system for sensing or measuring the motion of a fluid such as air. The system typically has a two-part plastic body containing an internal flow passage. The parts of the body may snap together or attach with an adhesive. A transducer or an electronic sensor is typically located within the flow passage, which may measure mass flow rate and may have two resistive thermal devices (RTDs) located on either side of a heat source. The body may have two elongated port tubes configured to attach to tubing. The port tubes may contain venturis, and may be substantially straight and substantially parallel, forming a U shape. A metal lead frame may be provided in electrical communication with the sensor. The lead frame may be integrally molded within the body, and may have a lower coefficient of thermal expansion than the body. The internal flow passage and the sensor may be substantially symmetrical and measure the flow rate of the fluid substantially equally in either flow direction.

Abstract: A system for sensing or measuring the motion of a fluid such as air. The system typically has a two-part plastic body containing an internal flow passage. The parts of the body may snap together or attach with an adhesive. A transducer or an electronic sensor is typically located within the flow passage, which may measure mass flow rate and may have two resistive thermal devices (RTDs) located on either side of a heat source. The body may have two elongated port tubes configured to attach to tubing. The port tubes may contain venturis, and may be substantially straight and substantially parallel, forming a U shape. A metal lead frame may be provided in electrical communication with the sensor. The lead frame may be integrally molded within the body, and may have a lower coefficient of thermal expansion than the body. The internal flow passage and the sensor may be substantially symmetrical and measure the flow rate of the fluid substantially equally in either flow direction.