Ultraflux Uf 841, User Manual

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NT UF 841 CP GB (d) / June 2015
5) KH
The hydraulic coefficient KH is used with external probes (clamp-on or diametric intrusive). It is used to
determine the speed throughout the cross-section of the pipe from the average speed over a diameter. Its
value therefore depends on the speed and the flow conditions (laminar or turbulent).
(a) Laminar: The fluid veins are parallel to the axis of the
pipe. This results in a parabolic speed profile.
(a) Laminar flow
(b) Turbulent: The fluid veins are not parallel to the axis
of the pipe. This results in a "rectangular" speed profile.
(b) Turbulent flow
The KH can be calculated automatically ("Type KH = AUTO") or set manually.
In automatic mode, the viscosity of the fluid and the roughness of the inside of the pipe must be defined.
In manual mode, you can define the KH yourself (if you have a good understanding of the flow rate in your
pipe).
6) Deletion rate (Qeff)
The deletion rate is the flow rate below which the flow meter will display 0. This gives you a clear indication
of a flow rate considered to be null.