An undershot gate system controls flow of liquid through an open channel or pipe. The system includes a gate leaf adapted to be raised and lowered by a control to allow flow of liquid along the open channel or pipe. The gate leaf has a flow diverter at an end of the gate leaf to guide liquid under the gate leaf and through an opening when the gate leaf is in an open position.

The disclosure relates to a reflection unit applied to an ultrasonic anemometer and used to reflect ultrasonic waves from a transmitter, wherein the reflected ultrasonic waves are received by a receiver. The reflection unit comprises a reflection plate and further comprises a mesh cover layer structure covering on the upper surface of the reflection plate. In an embodiment of the present disclosure, the mesh cover layer is provided on the reflection plate, so that the raindrops/water droplets falling on the reflection unit can be quickly scattered on the surface of the reflection unit, thereby eliminating the irregular shape and high liquid accumulation formed on the surface of the reflection unit, ensuring the accuracy of ultrasonic anemometer measurements in wind and rain conditions.

A method for measuring a speed of a fluid includes transmitting an ultrasonic measurement signal; acquiring and digitizing a measurement portion of an ultrasonic measurement signal received after traveling a defined length to obtain measurement samples; estimate, from the samples, an amplitude of the measurement portion; access reference samples forming a reference curve which is an interpolation of the measurement samples; produce adjusted measurement samples by multiplying the samples by ratio between an amplitude of the reference curve and the amplitude of the measurement portion; determine a unit time delay between the adjusted measurement sample and the reference curve; estimate a zero-crossing time of the measurement portion from the unit time delay and from the reference samples, estimate, from an average of the zero-crossing times, the time it takes the ultrasonic measurement signal to travel the defined length; estimate the speed of the fluid from the travel time measurement.

An omnidirectional anemometer and a method for using such an anemometer to measure the airflow along a conveying path, such as a helical path through a processing chamber. The anemometer is a low-profile, omnidirectional, three-axis anemometer with minimal airflow-occluding structure. Because of its low profile, the anemometer can fit in spiral conveyors with a short tier pitch.

A method for measuring a velocity of a fluid, comprising the steps of, acquiring an ultrasonic measuring signal after it has travelled in the fluid over a path of defined length; defining measurement zone of the ultrasonic measuring signal which includes a plurality of measurement lobes; for each measurement lobe, measuring a zero crossing point associated with said measurement lobe; selecting at least two zero crossing points which satisfy a predefined precision criterion; estimating a time of flight for the ultrasonic measuring signal from the selected zero crossing points; utilizing the time of flight to estimate the velocity of the fluid.

A method, apparatus, and system according to which first and second transducers are connected to first and second waveguides, respectively, the first and second waveguides are connected to a pipe, and ultrasonic wave signals are exchanged between the first and second transducers, said ultrasonic wave signals passing through the first and second waveguides, the pipe, and a fluid in the pipe. A temperature of the fluid flowing in the pipe may exceed about 600° C. The first and second waveguides insulate the first and second transducers from the pipe and propagate the ultrasonic wave signals between the pipe and the first and second transducers, respectively, so that the ability of the first and second transducers to exchange the ultrasonic wave signals is not adversely affected by the temperature of the fluid in the pipe. The first and second waveguides may be made of a calcium silicate technical ceramic.

A method of measuring the speed of a fluid, comprising the successive steps of: causing the processor component to emit at the same emission time both a first electrical excitation signal that is applied as input to a first transducer and also a second electrical excitation signal that is applied as input to a second transducer, such that the first transducer generates a first ultrasonic signal and such that the second transducer generates a second ultrasonic signal; putting the processor component on standby; reactivating the processor component after a predetermined standby duration; causing the first ultrasonic signal to be acquired by the second transducer and then by the processor component, and causing the second ultrasonic signal to be acquired by the first transducer and then by the processor component; using a value DToF to estimate the speed of the fluid.

A method and corresponding device are provided for determining a flow speed in a fluid conduit. The fluid conduit is provided with first, second and third ultrasonic wet transducers, wherein respective connection lines between transducers extend outside of a direction of average flow of the fluid conduit. First and second measuring signals are applied to the first ultrasonic wet transducer and received at the second and the third ultrasonic wet transducer, respectively. The measuring signals comprise a respective reversed signal portion with respect to time of a response signal. Respective first and second response signals are measured and the flow speed is derived from at least one of the first and second response signals.

An acoustic airspeed sensor system can include at least one acoustic transmitter configured to provide an acoustic pulse, a plurality of acoustic receivers including at least a first acoustic receiver, a second acoustic, receiver, and a third acoustic receiver, each positioned at a first radial distance from the at least one acoustic transmitter. The first acoustic receiver, the second acoustic receiver, and the third acoustic receiver are each configured to receive the acoustic pulse at a first time, a second time, and a third time, respectively, and output a first receiver signal, a second receiver signal, and a third receiver signal respectively. The system can include a computation unit operatively connected to the acoustic receivers and configured to generate a propagation function. The computation unit is further configured to determine true air speed based upon a receiver signals and the propagation function.

A flowmeter for measuring a flow of a fluid has a sensing element that has a pipeline for the fluid with a pipe wall, at least one phased array ultrasonic transducer unit, which can emit ultrasonic signals into different emission angles and can receive ultrasonic signals from different reception angles, a control and evaluation unit that is designed to control the ultrasonic transducer unit for emitting the ultrasonic signals along a measurement path and for evaluating the received ultrasonic signals and determining a flow using transit times of the ultrasonic signals. The sensing element has at least one reflector, which is designed to reflect the ultrasonic signals emitted by the ultrasonic transducer unit back to the same ultrasonic transducer unit. The ultrasonic signals pass through the measurement path from the ultrasonic transducer unit to the reflector and back to the ultrasonic transducer unit on at least partially different path sections.