Fluid Components International CMB - Manual (Page 21)

Type of fluid Position Assessment
Slurries Standard installation
position
Optimal installation position
Position A High density substances could accumulate in the flow-
meter
Position B Gas bubbles could accumulate
Position C Gas bubbles or high density substances could accumu-
late in the flowmeter
3.5.4 Pressure surges
Pressure surges in a pipe could be provoked by a sudden decrease in flow caused by rapid closing of a
valve or similar factors. This change in pressure can lead to underpressure downstream from a valve that
has been closed rapidly, and to outgasing. If the valve is mounted directly on the inlet section of the
flowmeter, a gas bubble can form in the flow tube that can cause a measuring signal disturbance that
would shift the zero point of the output signal. In extreme cases, a pressure surge could cause mechani-
cal damage to the sensors and/or flow tube.
Whenever possible, quick-closing valves should be mounted downstream from the sensor. If this is not
feasible, such valves are to be mounted a minimum of 10 x DIA (Φ) from the nearest sensor. Alterna-
tively, valve closing speed can be reduced.
3.5.5 Using the device with hazardous fluids
The sealing technology used in the standard mass flowmeter renders the device unsuitable for use with
hazardous fluids. Only sensors that meet the standards for safety instruments are suitable for use with
hazardous fluids.
The pathway between the sensor and transmitter must be pressure-tight so as to prevent fluid from leak-
ing out of a sensor in the event a sensor develops a defect.
In the case of welded components, a colored liquid penetration test should be performed on the welds, or
one joint (only the first one) should be x-rayed. Alternatively, an internal pressure monitoring device can
be used to detect any defect.
3.5.6 Vibration stability
The sensors are insensitive to vibration; vibration stability has been validated in accordance with
DIN IEC 68-2-6, for up to 1 g at 10 to 150 Hz.
If pipe vibration is greater than 1 g in the 10-150 Hz range, an additional fastening is to be mounted as
shown in the following drawings. This fastening will prevent vibration from affecting the device’s mechani-
cal configuration and/or measurement readings. The following drawings are valid for a sensor with a
nominal size of approximately 2 inches [DN 040]. Installation is to be realized as shown in this drawing.
CMB & CT OPERATING MANUAL
Part No 06EN003384 rev. 1.6 Page 21 of 106