Siemens SITRANS 7ME3500, Operating Instructions Manual, Page: 60 / 296

Connecting
5.5 Sensor Installation
FUE1010 IP65 NEMA 4X
58
Operating Instructions, 12/2014, A5E03086491-AC
Selecting a location for the sensors
1. Locate the sensors downstream from the center of the longest available straight run. A
location ten pipe diameters or greater downstream from the nearest bend will provide
adequate flow profile conditions.
2. Do not, if possible, install the sensors downstream from a throttling valve, a mixing tank,
the discharge of a positive displacement pump or any other equipment that could possibly
aerate the liquid. The best location will be as free as possible from flow disturbances,
vibration, sources of heat, noise, or radiated energy.
3. Avoid mounting the sensors on a section of pipe with any external scale. Remove all
scale, rust, loose paint, etc., from the location.
4. Do not mount the sensors on a surface aberration (pipe seam, etc.)
5. Do not mount sensors from different ultrasonic flow meters on the same pipe. Also, do not
run the sensor cables in common bundles with cables from other instrumentation. You
can run these cables through a common conduit ONLY if they originate at the same flow
meter.
6. Never mount sensors under water, unless you order submersible units and you install
them in accordance with factory instructions.
7. Avoid mounting sensors on the top or bottom of a horizontal pipe. The best placement on
a horizontal pipe is either the ten o’clock and two o’clock position for Reflect Mode, or one
sensor at nine o’clock and one sensor at three o’clock for Direct Mode. Mounting on a
vertical pipe is recommended only if flow is in the upward direction. When mounting on a
vertical pipe flowing in a downward direction make sure there is sufficient back pressure
in the system to maintain a full pipe.
①
Dual Path, Reflect Mount
②
Dual Path, Direct Mount
Figure 5-9 Sensor Alignment (Horizontal Plane)
Preparing the Pipe
1. Pick a mounting location with the longest straight run. You must have easy access to at
least one side of your pipe. The pipe at the mounting location must remain full, even at
zero flow.
2. Decide on your mounting mode (Direct or Reflect). Always use Reflect Mode whenever
possible. You may only need to use Direct Mode if your pipe is plastic.
3. After receiving the spacing dimensions from the Installation Menu, prepare the pipe
surface. De-grease the surface, if necessary, and remove any grit, corrosion, rust, loose