Unpacking; Site Considerations; Electronics Enclosure Location; Flowcell Location - GE AquaTrans AT868 User Manual

September 2004

Unpacking

Site Considerations

Electronics Enclosure
Location

Flowcell Location

Transducer Location

1-2
Carefully remove the electronics enclosure, the transducers, and the
cables from the shipping containers. Before discarding any of the
packing materials, account for all components and documentation
listed on the packing slip. The discarding of an important item along
with the packing materials is all too common. If anything is missing
or damaged, contact the factory immediately for assistance.
Because the relative location of the flowcell and the electronics
enclosure is important, use the guidelines in this section to plan the
AT868 installation.
The standard Model AT868 electronics enclosure is a powder-coated
aluminum NEMA 4X, IP66 weatherproof. Typically, the enclosure is
mounted as close as possible to the transducers. When choosing a
site, make sure the location permits easy access to the electronics
enclosure for programming, maintenance and service.
Note: For compliance with the European Union's Low Voltage
Directive (73/23/EEC), this unit requires an external power
disconnect device such as a switch or circuit breaker. The
disconnect device must be marked as such, clearly visible,
directly accessible, and located within 1.8 m (6 ft) of the
Model AT868.
Ideally, choose a section of pipe with unlimited access; for example, a
long stretch of pipe that is above ground. However, if the flowcell is
to be mounted in an underground pipe, dig a pit around the pipe to
facilitate installation of the transducers.
For a given fluid and pipe, the Model AT868's accuracy depends
primarily on the location and alignment of the transducers. In addition
to accessibility, when planning for transducer location, adhere to the
following guidelines:
•
Locate the transducers so that there are at least 10 pipe diameters
of straight, undisturbed flow upstream and 5 pipe diameters of
straight, undisturbed flow downstream from the measurement
point. Undisturbed flow means avoiding sources of turbulence in
the fluid such as valves, flanges, expansions, and elbows; avoiding
swirl; and avoiding cavitation.
•
Locate the transducers on a common axial plane along the pipe.
Locate the transducers on the side of the pipe, rather than the top or
bottom, since the top of the pipe tends to accumulate gas and the
bottom tends to accumulate sediment. Either condition will cause
increased attenuation of the ultrasonic signal. There is no similar
restriction with vertical pipes. However, vertical pipes with
downward flow should be avoided in order to insure a full pipe at
the measurement point.
Installation