A flowmeter is configured to measure a flow rate of a gas flowing through a main passage. The flowmeter includes a housing and a flow rate detector. The housing is made of a resin and includes a bypass passage branched off from the main passage. The flow rate detector is disposed in the bypass passage and transmits detection signals in accordance with the flow rate of the gas flowing through the main passage. The housing includes a non-insulation portion including graphite.

A flowmeter is disposed in a passage through which a fluid flows. The flowmeter includes a first passage and a second passage. The first passage defines an opening through which a part of the fluid flows into the flowmeter from the passage. The second passage branches off from the first passage and includes a flow rate detector configured to detect a flow rate of the fluid flowing through the second passage from the first passage. The second passage has one end at which the second passage branches off from the first passage and the other end. The second passage includes at least one end opening at the other end and an inflow reducer configured to restrict the fluid from flowing into the second passage through the at least one end opening.

We disclose herein a flow sensor assembly comprising a first substrate, a flow sensor located over the first substrate, a lid located over the flow sensor, a flow inlet channel, and a flow outlet channel. A surface of the flow sensor and a surface of the lid cooperate to form a flow sensing channel between the flow inlet channel and the flow outlet channel, and a surface of the flow sensing channel is substantially flat throughout the length of the flow sensing channel.

We disclose herein a flow sensor comprising: a first substrate comprising an etched portion, a dielectric region located on a first side of the first substrate, wherein the dielectric region comprises at least one dielectric membrane located over the etched portion of the first substrate, a sensing element located on or within the dielectric membrane, and a second substrate adjoining a second side of the first substrate. The first side of the first substrate and the second side of the first substrate are opposite sides. The first substrate and the second substrate cooperate to form a sensing channel through the flow sensor.

A system includes a downhole tool having a housing and a passage extending through the housing, where the passage includes an inlet configured to receive a flow of a wellbore fluid and an outlet configured to discharge the flow of the wellbore fluid. The downhole tool includes a heating element configured to heat the flow of the wellbore fluid and to enable the flow of the wellbore fluid to transition to a single-phase fluid flow within the passage. The downhole tool includes a phase composition sensor positioned adjacent the passage and configured to provide feedback indicative of formation of the single-phase fluid flow. The system includes a controller configured to monitor a power consumption of the heating element and to determine an enthalpy of the wellbore fluid based in part on the power consumption and the feedback from the phase composition sensor.

Mass flow meters and mass flow controllers that include mass flow meters are disclosed. A mass flow meter includes a main flow path for a gas, and a bypass with a length, L, within the main flow path. The bypass includes a continuous flow section including a plurality of continuous capillary tubes that each have a length, L. The bypass also includes n flow segments forming n1 spaces within the bypass where n is greater than or equal to 2, and each of the flow segments has a plurality of capillary tubes. The mass flow meter also includes at least one thermal sensor including a sensor tube, and the sensor tube is positioned across at least one of the flow segments to divert a portion of the gas around the at least one of the flow segments and provide a measured flow signal in response to the diverted portion of the gas.

A method for measuring a flow of a fluid in a tube includes heating the fluid in the tube with a heating element. A first signal is measured with a first temperature sensing element at a first location. A second signal is measured with a second temperature sensing element at a second location. At least one temperature signal is calculated based on the first signal and the second signal. The at least one temperature signal includes a difference temperature signal and a sum temperature signal. The difference temperature signal is calculated based on a difference between the second signal and the first signal. The sum temperature signal is calculated based on a sum of the second signal and the first signal. The flow is derived based on the difference temperature signal, the sum temperature signal, or a combination thereof.

A multi-purpose Micro-Electro-Mechanical Systems (MEMS) thermopile sensor able to use as a thermal conductivity sensor, a Pirani vacuum sensor, a thermal flow sensor and a non-contact infrared temperature sensor, respectively. The sensor comprises a rectangular membrane created in a silicon substrate which has a thin polysilicon layer and a thin residual thermal reorganized porous silicon layer both attached on its back side, and configured to have its three sides clamped to the frame formed in the silicon substrate which surrounds and supports the membrane and the other side free to the frame, a cavity created in the silicon substrate, positioned under the membrane and having its flat bottom opposite to the membrane, its three side walls shaped as curved planes and the other side wall shaped as a vertical plane, a heater or an infrared absorber positioned on the membrane, close to and parallel with the free side of the membrane and a thermopile positioned on the membrane and consists of several thermocouples connected in series and having its hot junctions close to the heater and its cold junctions extended to the frame.

An electric measurement method and apparatus for detecting a mass by an electric capacity (permittivity) or a material's dielectric constant, or alternatively, electric inductance (permeability). The mass may be any phase or combination of phases. The mass may be stationary or flowing. It may comprise discrete particles such as grain, or manufactured products such as ball bearings or threaded fasteners, etc. The mass may be a flow element in a rotameter or similar flow measurement device. The sensor comprises a volume which may be completely full or only partially full of the material. The material may be discrete components or a continuum. Sensor signals may be received by existing planter monitoring systems. In some embodiments the flow sensors are positioned external to the application port. In some embodiments sensors may be utilized which are responsive to the refractive index variation of specific chemicals.

Capillary-type mass flow meters and controllers are described that employ temperature sensor hardware providing boundary conditions as necessary for direct computation of mass flow rate. The approach offers dramatically improved operable range and other potential benefits as compared to known systems.