Abstract: A coriolis flow sensor is disclosed. The coriolis flow sensors comprises a first substrate layer, a second substrate layer, and a third substrate layer. The first substrate layer comprises a first wall. The second substrate layer comprises a second wall. The third substrate layer is disposed between the first and second substrate layers in a stacked configuration. The third substrate layer defines a flow path. The first and second walls of the respective first and second substrates and the flow path defined by the third substrate layer define a first flow channel configured to receive a fluid therethrough. A first actuator is configured to generate vibrations in the first flow channel. The first flow channel is mechanically moveable.

Abstract: A coriolis flow sensor is disclosed. The coriolis flow sensors comprises a first substrate layer, a second substrate layer, and a third substrate layer. The first substrate layer comprises a first wall. The second substrate layer comprises a second wall. The third substrate layer is disposed between the first and second substrate layers in a stacked configuration. The third substrate layer defines a flow path. The first and second walls of the respective first and second substrates and the flow path defined by the third substrate layer define a first flow channel configured to receive a fluid therethrough. A first actuator is configured to generate vibrations in the first flow channel. The first flow channel is mechanically moveable.

Abstract: A flow sensor including a symmetrical sensor tube for carrying the fluid, first and second heaters symmetrically disposed at the sensor tube, and a first temperature sensor in thermal communication with the fluid. A flow meter including a flow sensor having a sensor tube, a first heater disposed at the sensor tube, a second heater disposed at the sensor tube, and a first temperature sensor in thermal communication with the fluid. The meter also includes a circuit for selectively applying power to the first and second heaters to maintain a temperature difference between a temperature of the first and second heaters and the temperature of the fluid, and for determining a difference in power supplied to the first and second heaters.

Abstract: A laminar flow element for use in flow metering devices has a laminar flow element plug with an upstream end and a downstream end and a linear extent between the upstream end and the downstream end, the laminar flow element plug configured to be positioned within a base cavity with the upstream end oriented toward the direction of flow, and sensor taps through walls of the base cavity positioned inboard of the laminar flow element plug so that entrance effect is eliminated, error due to flow cross-sectional area differential is eliminated, and orifice effect is minimized, to produce a laminar flow with linear pressure drop across the sensor taps as a function of flow rate. Coaxial laminar flow guides are fixed coaxially about at least a portion of the length of the laminar flow element plug to increase the number of flow passages to enable linear measurements of higher flow rates.

Abstract: A miniaturized silicon based thermally controlled vacuum sensor uses thin film resistors on a membrane in a minute measuring chamber to accurately detect vacuum pressures in the range of 760 Torr to 1.times.10.sup.-5 Torr. The configurations of the measuring chamber and gas diffusion port of the sensor structure insure that heat transfer from the membrane is predominately conductive over the pressure detection range to provide linear output up to 0.1 Torr. A microprocessor is used to control and measure power required to maintain a predetermined temperature differential between a sensing resistive element on the membrane and an ambient temperature sensing element of the sensor base from analog voltage and current values. Pressure detection errors introduced by ambient temperature variations are minimized by measuring power dissipated into the gas. Analog and digital converters for both current and voltage signals use a .SIGMA.-.DELTA.