ADS Environmental Services Model 3600 530002 A2 - Manual (Page 68)

Ring, Sensor, and Special Installations 4-35
"C" or 3/4 Ring Velocity Special
ADS-3004
Front View Typical Pipe
D.
B.
C.
A.
3/4 Ring
Velocity
Sensor
Crown
Invert
Flow Line
Point E.
Anchor
Bolt
(1 of 4)
Pre-Installation Assembly
l Position the metal band so that the small holes drilled along the edge of the
ring are facing towards you. This is the downstream side of the band.
l Check the site report to determine if the cable route and entry will be from the
left, middle, or right of the designated installation position. This determines
which side of the band will be the short end of the velocity band. The short
end of the band is the side opposite of the pipe where entry occurs. If one
enters in the middle of the pipe, it will not make a difference.
l Once the short end has been designated, locate the second pre-drilled hole
down from the short end of the band.
l Check the site report for silt measurement and DOF at investigation.
l If silt is present at the site, the velocity sensor mounting point must be
relocated up the side of the band so that it will be clear of any silt when
installed.
— OR —
If silt is not present, you must determine the location in which the velocity
sensor is attached on the band.
l If holes do not already exist at or near the mark, drill holes in the band for the
velocity sensor using a 3 mm (7/32 in.) drill bit (near depends on the amount
of flow in the line). In large pipes, flow levels are usually high enough that one
can be off several inches. The critical concern is to make sure the sensor is
covered with flow at its lowest level.