Damping - Siemens SITRANS F Operating Instructions Manual

Installing/Mounting

4.5 Damping

● Align the flanges in order to achieve an installation free from strain.
● Use mounting screws and gaskets of the prescribed dimensions. The gaskets must be
● Tighten the screws crosswise so that the process connections are sealed. The tightening
● Ensure that the pipe has been mounted securely enough to exclude any vibration or
● Do not use steel mounting brackets on the instrument!
Gas applications
Pay particular attention to the positioning of the valve when gas is to be measured. If the
instrument is absolutely calibrated for a pressure exceeding 1.013 bar, the valve is usually
installed in the outlet of the flowmeter.
In order to prevent compression oscillation during gas measurements, a throttle must be
arranged immediately behind the measuring instrument. In order to avoid erroneous
measurements, the arrangement must be selected to ensure that the pressure prevailing in
the measuring instrument corresponds to the reference pressure of the calibration.
4.5 Damping
Variable area flowmeter damping is recommended:
● In general during the measurement of gas
● If air bubbles in the medium cannot be avoided
● If shock pressure predominates in the pipes, arising through a delay in the flow, e.g. due
● If turbulence, pulsations or any other type of instability in the variable area flowmeter
● If the flow pressure cannot be built up slowly
● If vibrations in the line cannot be avoided
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appropriate for the operating pressure, the temperature and the process media.
CAUTION
PTFE-lined devices
For PTFE-lined instruments, use gaskets where the inner and outer dimensions conform
with the raised face of the device.
torque for the screws must be adhered to especially in the case of PTFE-lined devices.
The flange screws for PTFE-lined fittings may only be tightened with the following
maximum torques (VDI/VDE Guideline 3513):
– DN 15 to 25 (½" to 1"): 14 Nm
– DN 50 (2"): 25 Nm
– DN 80 (3"): 35 Nm
– DN 100 (4"): 42 Nm.
oscillation.
to rapid throttling or shut-off
could lead to vibration
Operating Instructions, 02/2013, A5E03821131-01
SITRANS FVA250