Abstract: The invention provides an undershot sluice gate (17) to control flow of liquid through an open channel (10). The gate (17) includes a gate leaf (18) adapted to be raised and lowered by a control means (22) to allow flow of liquid along open channel (10). Gate leaf (18) has at least a pair of opposing liquid level sensors (44, 46) on, or in, gate leaf (18) to provide measurement of liquid level upstream and downstream of gate leaf (18). The sensors (44, 46) are located at a predetermined distance from the lowermost edge of gate leaf (18) to allow said measurements without disturbance from the fluid flow profile resulting from movement of liquid beneath the lowermost edge of gate leaf (18).

Abstract: The invention provides an undershot sluice gate (17) to control flow of liquid through an open channel (10). The gate (17) includes a gate leaf (18) adapted to be raised and lowered by a control means (22) to allow flow of liquid along open channel (10). Gate leaf (18) has at least a pair of opposing liquid level sensors (44, 46) on, or in, gate leaf (18) to provide measurement of liquid level upstream and downstream of gate leaf (18). The sensors (44, 46) are located at a predetermined distance from the lowermost edge of gate leaf (18) to allow said measurements without disturbance from the fluid flow profile resulting from movement of liquid beneath the lowermost edge of gate leaf (18).

Abstract: The invention provides an undershot sluice gate (17) to control flow of liquid through an open channel (10). The gate (17) includes a gate leaf (18) adapted to be raised and lowered by a control means (22) to allow flow of liquid along open channel (10). Gate leaf (18) has at least a pair of opposing liquid level sensors (44, 46) on, or in, gate leaf (18) to provide measurement of liquid level upstream and downstream of gate leaf (18). The sensors (44, 46) are located at a predetermined distance from the lowermost edge of gate leaf (18) to allow said measurements without disturbance from the fluid flow profile resulting from movement of liquid beneath the lowermost edge of gate leaf (18).

Abstract: The invention provides a level detection device (32) having a tube (34) which, in use, contains a material (14) for which its level in the tube (34) is to be measured. An ultrasonic transducer (10) is provided at one end of tube (34) for emitting an acoustic waveform that reflects off the surface of the level and returns to the ultrasonic transducer (10) to allow computation of the level from the time periods of the emitted and reflected acoustic waveforms. A flared section (22) within tube (34) diverges from adjacent ultrasonic transducer (10) towards the inside wall of tube (34) above the level, whereby, in use, the measured reflected waveform has substantially reduced signal distortion due to flare (22).