Etaeval GmbH products

etaeval carries out temporarily installed acoustic discharge measurements or will be pleased to advise you on installations for continuous operation.

Flow rate measurements with propeller type current meters. In case of short intakes, open channel flows, and also closed conduits propeller type current meter can be used. The procedures are described in the IEC (International Electrotechnical Commission) standard 60041 "field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump turbines". The following three images depict a typical installation, which was performed with current meters fixed in the stop log notches in the intake of a low head hydro plant.

Transient operation is inherent to the operation of hydroelectric power plants and water supply systems, since machines are started, stopped or work at time varying operating conditions. Water hammer and/or mass oscillations may occur. Due to the elasticity of the pipes, the compressibility of the water and of air bubbles, pressures pulsations propagate in closed conduits through the water at a propagation speed being lower than the speed of sound in water of 1440 m/s. If no precaution is taken water hammer may become destructive. For any modification of the control system the effect on pressure pulsations and water hammer must be checked. In systems with open channel transients lead to free surface variations.

Noise emission guarantees are often part of contracts in case of new or revised hydraulic machines in hydro power or water supply plants.

We employ numerical flow simulations for determination of the uncertainty of the flow rate integration for ultrasonic flow meters, when the installation is exposed to an upstream flow distortion and a resulting nonuniform velocity distribution occur.