A fluid flow meter comprising a fluid pump to displace fluid with pumping strokes of one or more pumping stroke types wherein each of the one or more stroke types displaces a known volume of fluid, a sensor functionally associated with a fluid reservoir and adapted to generate a signal indicative of a fluid pumping condition within the fluid reservoir, which fluid reservoir is integral or functionally associated with the pump, and circuitry to trigger one or a sequence of strokes of the pump in response to a signal from the sensor.

A multiphase fluid is flowed from a flow pipe to a U-bend. Several differential pressures of the multiphase fluid flowing through the flow pipe and U-bend are measured. A mixture density of the multiphase fluid is determined at least based on the measured differential pressures. A total flow rate of the multiphase fluid is determined at least based on the measured differential pressures. In some cases, flow rates of each of the phases of the multiphase fluid can be determined at least based on the measured differential pressures.

An air flow measuring device is adapted to be attached to a duct. The device includes a first housing, a second housing, and a flow sensor. The first housing defines a bypass flow passage which takes in a part of air flowing in the duct, and includes a hollow part and a recess. The bypass flow passage is formed in the hollow part. The recess is formed on an upper side of the hollow part in a vertical direction of the device, and at the recess, an outer surface of the first housing is recessed inward of the first housing. The second housing is formed through secondary formation with the first housing as a primary formed part. The first housing is held on a lower side of the second housing in the vertical direction. The flow sensor is disposed in the bypass flow passage.

An air flow measuring device is adapted to be attached to a duct. The device includes a first housing, a second housing, and a flow sensor. The first housing defines a bypass flow passage which takes in a part of air flowing in the duct, and includes a hollow part and a recess. The bypass flow passage is formed in the hollow part. The recess is formed on an upper side of the hollow part in a vertical direction of the device, and at the recess, an outer surface of the first housing is recessed inward of the first housing. The second housing is formed through secondary formation with the first housing as a primary formed part. The first housing is held on a lower side of the second housing in the vertical direction. The flow sensor is disposed in the bypass flow passage.

A flow conditioner includes a plate having a hole pattern and a flange surrounding the plate; and at least one pressure tap that is integral with the flow conditioner. The at least one pressure tap is on at least one of a first face of the flow conditioner, a second face of the flow conditioner, within a hole, or any combination thereof.

A fluid flow sensor for use in measuring flow parameters in gas and other fluid applications, including patient ventilators and the like. The sensor is characterized by a lower pressure drop at higher flow rates in order to minimize patient effort in breathing.

A multiphase fluid is flowed from a flow pipe to a U-bend. Several differential pressures of the multiphase fluid flowing through the flow pipe and U-bend are measured. A total flow rate of the multiphase fluid is determined at least based on the measured differential pressures. In some cases, flow rates of each of the phases of the multiphase fluid can be determined at least based on the measured differential pressures.

The present invention discloses a negative pressure wave monitoring based leak detection method of a multipath pipeline network, including: analyzing a propagation process of a negative pressure wave in a single straight pipeline to obtain a calculated result of a sound velocity in a thin-walled pipe marking the pressure sensors at known disposing positions on a pipeline network map; linearly interpolating position coordinates of key nodes in the pipeline network to extend pipeline network information; resolving the time that a negative pressure wave signal generated by a leak propagates to each disposed RTUs to form a data column; and simulating a leak situation, detecting a pipeline pressure waveform by using the RTUs in a current network, and determining a point corresponding to the data column closest to a measured propagation time delay in the time delay standard library as a leak point, and outputting the position of the leak point.

The present invention discloses a negative pressure wave monitoring based leak detection method of a multipath pipeline network, including: analyzing a propagation process of a negative pressure wave in a single straight pipeline to obtain a calculated result of a sound velocity in a thin-walled pipe marking the pressure sensors at known disposing positions on a pipeline network map; linearly interpolating position coordinates of key nodes in the pipeline network to extend pipeline network information; resolving the time that a negative pressure wave signal generated by a leak propagates to each disposed RTUs to form a data column; and simulating a leak situation, detecting a pipeline pressure waveform by using the RTUs in a current network, and determining a point corresponding to the data column closest to a measured propagation time delay in the time delay standard library as a leak point, and outputting the position of the leak point.

A method includes opening a flow path from a gas stick through a variable orifice, a chamber, and an outlet isolation valve of the chamber. The method further includes causing a gas to flow through the flow path at a flow rate setpoint. The method further includes actuating an opening of the variable orifice to establish a choked pressure regime within the chamber, the choked pressure regime being achieved by causing a first pressure upstream of the variable orifice to be at least two times a second pressure downstream of the variable orifice. The method further includes closing the outlet isolation valve to cause the chamber to be filled with the gas from the gas stick. The method further includes measuring a pressure rate-of-rise within the chamber. The method further includes determining one or more flow measurements based at least in part on the pressure rate-of-rise.