Penstock flow rate measurement


Energy has become a priority issue (due to the depletion of fossil fuels and the production and operation costs of nuclear energy, etc.). As a result, electricity production by hydroelectric power plants has become an interesting alternative, because it is natural and does not create pollution. There is a large and ever-growing number of plants (more than 1,500 with a small, medium or large production capacity). It is therefore vital to control and optimise the yield of these plants. This is why Ultraflux offers its clients a debit meter that is capable of responding to this objective of knowing the yield of their plants as precisely as possible.


Ultraflux was asked to equip pipes in a hydroelectric plant situated within a mountain range. We were asked to install multi-chord ultrasound flow meters on existing pipes with large diameters (1,800 to 2,700mm). To do this, we needed to take into account hydraulic, time and access constraints in relation to the various sites to be equipped.

Conduites forcées SHEM


Uf 831 CO converters Intrusive probes
Convertisseur Uf 831  Sonde intrusive
These devices enable us to measure between one and eight speeds, depending on the version. The chosen probes allow for mounting and dismantling under load and can withstand a pressure of 100 bars.


In order to satisfy our client’s requirements, the measurement uncertainty of the measurement points must be better than 1%.


  • Measures speed over several sections so that the various flow speeds can be taken into account,
  • Controlled and highly reliable measurement uncertainty,
  • Probes can be mounted under load,
  • Very dynamic measurements,
  • Good repeatability.

The Ultraflux solution:

  • Overall project management (choice of subcontractors, project supervision, etc.),
  • Full study capable of integrating the hydraulic profile of the flow (using a specific piece of software),
  • Control of the section of pipe (dimensional arm, thickness gauge),
  • Controlled costs (regardless of the pipe diameter and the installation of the flow meter),
  • Production is not shut-down to install the equipment and the pipe is not cut,
  • Little to no mechanical stress on the pipework.