2: Installation
10
U3000/U4000 User Manual
(Issue 2.0)
Power connections
The instrument can be powered from a mains supply (86 - 264V a.c., 47/63Hz) or from a 24V a.c./d.c. supply
if it is fitted with a 24V supply module.
1.
Route the power cable through one of the two cable glands on the right hand side of the instrument,
below the power connection terminals, using the gland most suitable for the cable diameter.
2.
Cut the wires to length, strip back the insulation by approximately 10mm and connected to them into the
correct power supply terminals identified in
Figure 2.1
.
3.
On completion, tighten the cable glands to ensure the cables are held securely.
4.
Refit the terminal block cover.
2.3
Installing The Ultrasonic Transducers
2.3.1 Transducer
positioning
Figure 2.3 Locating the transducers
To obtain the most accurate results the condition of both the liquid and the pipe wall must be suitable to allow
the ultrasound transmission along its predetermined path. It is important also that the liquid flows uniformly
within the length of pipe being monitored and that the flow profile is not distorted by any upstream or
downstream obstructions. This is best achieved by ensuring there is a straight length of pipe upstream of the
transducers of at least 20 times the pipe diameter and 10 times the pipe diameter on the downstream side, as
WARNING
LETHAL VOLTAGES
Ensure the power cable is isolated from the mains supply.
Do not apply mains voltage with the terminal cover removed.
Flow
Valid transducer location
10 x Diameter
20 x Diameter
45°
The U3000/U4000 equipment expects a uniform flow profile
as a distorted flow will produce unpredictable measurement
errors. Flow profile distortions can result from upstream
disturbances such as bends, tees, valves, pumps and other
similar obstructions. To ensure a uniform profile the
transducers must be mounted far enough away from any
cause of distortion such that it no longer has an effect.
Uniform Flow Profile
Distorted Flow Profile
In many applications an even flow velocity profile over
a full 360° is unattainable due, for example, to the
presence of air turbulence at the top of the flow and
possibly sludge in the bottom of the pipe. Experience
has shown that the most consistently accurate results
are achieved when the transducer guide rails are
mounted at 45° with respect to the top of the pipe.
Possible
sludge
Air
Flow
Guide
rail
