A method of measuring the speed of a fluid comprising the following steps: generating a plurality of pseudorandom frequencies (fus_n); for each pseudorandom frequency (fus_n), emitting ultrasound signals into the fluid to travel along a path of defined length; receiving the ultrasound signals; for each received ultrasound signal, producing a travel time measurement, so as to generate for each pseudorandom frequency (fus_n) a predefined number of travel time measurements; for each pseudorandom frequency (fus_n), evaluating the accuracy of the measurements; for evaluating the speed of the fluid, making use of the measurements produced for the pseudorandom frequency that presents the greatest accuracy.

An ultrasonic anemometer (7) as well as a method for determination of at least one component of a wind velocity vector and/or a velocity of sound includes at least one sound transducer at least temporarily working as a transmitter (1, 2, 3, 4, 5, 6, 15, 16) with a sound emission surface for emitting sound waves and at least one sound transducer at least temporarily working as a receiver (1, 2, 3, 4, 5, 6, 15, 16) with a sound detection surface for at least partially receiving the emitted sound waves. An evaluation unit, determines at least one component of a wind velocity vector and/or the velocity of sound, based on a recorded transit time, which the sound waves require on a measuring section located between the sound emission surface of the at least one transmittor and the sound detection surface of the at least one receiver to cover the distance of this measuring section. At least one measuring section is provided between a first sound emission surface of a first transmitter and a first sound detection surface of a first receiver arranged approximately vertical to the earth's surface and the first sound emission surface and/or the first sound detection surface is inclined compared to the horizontal.

An ultrasonic anemometer (7) as well as a method for determination of at least one component of a wind velocity vector and/or a velocity of sound includes at least one sound transducer at least temporarily working as a transmitter (1, 2, 3, 4, 5, 6, 15, 16) with a sound emission surface for emitting sound waves and at least one sound transducer at least temporarily working as a receiver (1, 2, 3, 4, 5, 6, 15, 16) with a sound detection surface for at least partially receiving the emitted sound waves. An evaluation unit, determines at least one component of a wind velocity vector and/or the velocity of sound, based on a recorded transit time, which the sound waves require on a measuring section located between the sound emission surface of the at least one transmittor and the sound detection surface of the at least one receiver to cover the distance of this measuring section. At least one measuring section is provided between a first sound emission surface of a first transmitter and a first sound detection surface of a first receiver arranged approximately vertical to the earth's surface and the first sound emission surface and/or the first sound detection surface is inclined compared to the horizontal.

Apparatus (10) and methods for making simultaneous measurements of composition (water-cut), fluid flow, and sound attenuation in a multiphase fluid flowing (15) through a pipe (12) in real-time, using the same apparatus (10) are described. Additionally, the apparatus (10) provides real-time pipe wall thickness monitoring for observing pipe corrosion or internal deposition. Knowledge of wall thickness is necessary to correct for water-cut (oil-water composition) automatically by adjusting the liquid path length internal to the pipe (spool). The use of short duration frequency chirp excitation signals (24) enables the apparatus to provide information that can be used to extract multiple levels of information from the same measurement in multiphase fluids including the presence of a significant quantity of gas (60% gas volume fraction) in different flow regimes. Besides measuring steady flow, this device is useful for measurements during fast changing flows, such as for a rod-pumped well. Measurements up to about 1000 times a second can reliably be made.

Apparatus (10) and methods for making simultaneous measurements of composition (water-cut), fluid flow, and sound attenuation in a multiphase fluid flowing (15) through a pipe (12) in real-time, using the same apparatus (10) are described. Additionally, the apparatus (10) provides real-time pipe wall thickness monitoring for observing pipe corrosion or internal deposition. Knowledge of wall thickness is necessary to correct for water-cut (oil-water composition) automatically by adjusting the liquid path length internal to the pipe (spool). The use of short duration frequency chirp excitation signals (24) enables the apparatus to provide information that can be used to extract multiple levels of information from the same measurement in multiphase fluids including the presence of a significant quantity of gas (60% gas volume fraction) in different flow regimes. Besides measuring steady flow, this device is useful for measurements during fast changing flows, such as for a rod-pumped well. Measurements up to about 1000 times a second can reliably be made.

The present invention provides a thermal flowmeter having good measurement accuracy by reducing deviation in the flow velocity distribution of a gas under measurement flowing through an auxiliary passage. An auxiliary passage 330 for taking in a portion of a gas under measurement IA flowing through a main passage 124 has a curved passage 32a that bends toward a flowrate measurement element 602. The curved passage 32a has a resistance portion 50 formed therein that applies resistance to the flow of the gas under measurement IA flowing through the outer peripheral side CO of the curved passage 32a so that the pressure loss of the gas under measurement IA flowing through the outer peripheral side CO is high compared to that of the gas flowing through the inner peripheral side CI of the curved passage 32a.

The invention relates to an instrument for measuring air speed by means of parabolic movement and to a measuring method, wherein the measuring instrument is formed by a cubic structure (1) that holds a screwable, flexible container (2) which releaseswhere air speed needs to be measureda drop of liquid, the drop falling on one of the concentric circles located on an interchangeable plate (3) that is positioned on a flat base (4) of the device and perpendicular to the axial end of the outlet for the drop of liquid. Dependingon the heightthe movement with which the drop falls, the air speed can be determined by means of the horizontal range of the parabolic movement followed by the drop of liquid, and evaluated using the distance between the point of impact of the drop on the surface with respect to the center. The direction of the air speed can also be determined from angle formed by the projection of the vertical plane above which projection the air moves in relation to the x-axis of the x-y plane located above the interchangeable plate (3).

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit configured to calculate a speed of the fluid by using the intensity of the light received at the sensor.

An apparatus and method for determining fluid flow (e.g., sterile media flow, filtrate flow, etc.) through tubing is provided. The apparatus includes an air source, a flow valve, a first sensor, a second sensor, and a media tubing section extending between the first sensor and the second sensor. In operation, air from the air source is introduced by the flow valve into a fluid flow to create a lead line of fluid immediately following the introduced air. As the lead line of fluid passes each sensor, the sensors are used to determine a time between when the lead line passes the first sensor and the second sensor and that determined elapsed time is used, along with a determined volume of the media tubing section to determine the rate of flow of the fluid flow.

An apparatus and method for determining fluid flow (e.g., sterile media flow, filtrate flow, etc.) through tubing is provided. The apparatus includes an air source, a flow valve, a first sensor, a second sensor, and a media tubing section extending between the first sensor and the second sensor. In operation, air from the air source is introduced by the flow valve into a fluid flow to create a lead line of fluid immediately following the introduced air. As the lead line of fluid passes each sensor, the sensors are used to determine a time between when the lead line passes the first sensor and the second sensor and that determined elapsed time is used, along with a determined volume of the media tubing section to determine the rate of flow of the fluid flow.