Abstract: A mass fluid flow controller has a valve which is controlled by a controller rod which is substantially pivotally mounted on a metallic diaphragm which stretches and unstretches with the movement of the rod. The actuation of the rod movement is by the expansion and contraction of an actuator wire which is heated for the expansion and allowed to cool for the contraction. The primary fluid flow path through the controller is straight. A sensor conduit, providing a parallel sensor fluid flow path, is connected in position using metallic sealer members which extend into openings to the primary fluid flow path and which are rounded along the direction through such openings. The pressure drop, along the primary fluid flow path, to create flow through the sensor conduit, is provided by a fluid flow restrictor having a core and having lengths of wire along the core which are squeezed between the core and a tapered fluid flow path wall in the vicinity of the sensor conduit input and output connections.

Abstract: A mass fluid flow controller has a valve which is controlled by a controller rod which is substantially pivotally mounted on a metallic diaphragm which stretches and unstretches with the movement of the rod. The actuation of the rod movement is by the expansion and contraction of an actuator wire which is heated for the expansion and allowed to cool for the contraction. The primary fluid flow path through the controller is straight. A sensor conduit, providing a parallel sensor fluid flow path, is connected in position using metallic sealer members which extend into openings to the primary fluid flow path and which are rounded along the direction through such openings. The pressure drop, along the primary fluid flow path, to create flow through the sensor conduit, is provided by a fluid flow restrictor having a core and having lengths of wire along the core which are squeezed between the core and a tapered fluid flow path wall in the vicinity of the sensor conduit input and output connections.

Abstract: A mass fluid flow controller has a valve which is controlled by a controller rod which is substantially pivotally mounted on a metallic diaphragm which stretches and unstretches with the movement of the rod. The actuation of the rod movement is by the expansion and contraction of an actuator wire which is heated for the expansion and allowed to cool for the contraction. The primary fluid flow path through the controller is straight. A sensor conduit, providing a parallel sensor fluid flow path, is connected in position using metallic sealer members which extend into openings to the primary fluid flow path and which are rounded along the direction through such openings. The pressure drop, along the primary fluid flow path, to create flow through the sensor conduit, is provided by a fluid flow restrictor having a core and having lengths of wire along the core which are squeezed between the core and a tapered fluid flow path wall in the vicinity of the sensor conduit input and output connections.

Abstract: An apparatus for verifying the calibration of a flow meter contains a flow sensor assembly which has a flow tube defining an axial fluid path through the flow sensor assembly; an upstream resistance thermometer in thermal contact with the flow tube; a downstream resistance thermometer in thermal contact with the flow tube, where the two thermometers are operationally connected to a means for producing an output in response to a difference between the heat flows from the first and second resistance thermometers; and means for asymmetrically transferring heat to the first and second resistance thermometers, independently of fluid flow through the flow tube. The calibration of the flow meter's thermal and electronic systems is verified by measuring the flow meter's output in response to a first asymmetric heat transfer, to the upstream and downstream resistance thermometers, when the flow meter is calibrated.

Abstract: A method of correcting measurement errors of an instrument for measuring the flow of a gas, the instrument having a selected measuring range and being constructed to produce a reading indicating the value of a gas flow in the selected measuring range, by the steps of: selecting a limited number of gas flow values which are spaced apart across the measuring range; determining the readings produced by the instrument when the instrument is measuring gas flows at the selected values; measuring the flow of the gas with the instrument to produce a reading indicating the value of the gas flow; and producing a corrected reading by calculating a function of the reading produced in the measuring step and the readings produced in the determining step.

Abstract: A split path mass flowmeter includes a housing having a longitudinally extending bore within which a flow splitter is positioned. The flow splitter includes a tapered portion having a taper corresponding generally to that of a tapered portion of the bore. The tapered portion of the flow splitter is nested within the tapered portion of the bore, the tapered portions of these elements thereby forming a self-holding retention section for non-adjustably retaining the flow splitter within the bore. The retention section may taper outwardly or inwardly in the direction of fluid flow. A calibration section may precede or follow the retention section or may be combined into the retention section. Further, a recovery section may be separately disposed downstream of the retention and calibration sections or may be combined along with the calibration function in the retention section.

Abstract: An apparatus for verifying the calibration of a flow meter contains a flow sensor assembly which has a flow tube defining an axial fluid path through the flow sensor assembly; an upstream temperature sensor in thermal contact with the flow tube; a downstream temperature sensor in thermal contact with the flow tube, the two sensors being operationally connected to a means for producing an output in response to a temperature difference between the first and second sensors; and means for asymmetrically transferring heat to the first and second temperature sensors independently of fluid flow through the flow tube. The calibration of the flow meter's thermal and electronic systems is verified by measuring the flow meter's output in response to a first asymmetric heat transfer to the upstream and downstream temperature sensors when the flow meter is calibrated.

Abstract: A flow meter has an elongate housing with a fluid inlet, a fluid outlet and an axial passage therebetween. The fluid passage contains a flow sensor assembly operationally connected in parallel to a flow splitter section. The flow sensor assembly has a flow tube forming an axial passage therethrough and the flow tube has a thermally diffusive sensor region. An upstream resistance thermometer and a downstream resistance thermometer are in thermal contact with the sensor region. The sensor region can additionally contain an electrically insulating coating on its outside surface and resistance thermometers formed by winding a single layer of a fine, uninsulated wire around its outside surface. The sensor assembly can be surrounded by inner and outer housings made of electrically and thermally conductive material connected to the flow tube near the ends of the sensor region and grounded to a printed circuit board.

Abstract: A flowmeter has an elongated housing with a fluid inlet, a fluid outlet and an axial passage therebetween. The fluid passage contains a flow splitter section and is connected to a flow sensor assembly. The flow splitter section is formed by a surface defining a longitudinal fluid path and a flow splitter secured in the fluid path, so as to form an annular gap between the surface of the fluid path and the flow splitter. The surface of the fluid path defines a tapered calibration bore. The flow splitter has a tapered calibration section comprising the upstream portion of the flow splitter and at least one tapered expansion section comprising the downstream portion of the flow splitter. The taper of the calibration section is substantially parallel to the taper of the calibration bore, and the taper of the expansion section diverges away from the taper of the calibration bore.