Alicat M Series Mass Flow Meter - Manual (Page 7)

7
We recommend the use of in-line sintered filters to prevent large
particulates from entering the measurement head of the instrument.
Suggested maximum particulate sizes are as follows:
5 microns for units with FS flow ranges of 0-1 sccm or less.
20 microns for units with FS flow ranges between 0-2 sccm and 0-1 slpm.
50 microns for units with FS flow ranges of 0-1 slpm or more.
Connecting Fittings and Filters
http://www.alicat.com/support/instructional-videos/
PRESSURE
Maximum operating line pressure for M-Series units is 145 psig (1 MPa).
If the line pressure is higher than 145 psig (1 MPa), use a pressure regulator
upstream from the flow meter to reduce the pressure to 145 psig (1 MPa) or less.
Maximum operating line pressure for WHISPER units is 50 psig.
Exceeding the maximum specified line pressure may cause permanent
damage to the solid-state differential pressure sensor.
Do Not subject an M-Series Differential Pressure sensor to
upstream-downstream pressure differentials exceeding 75 PSID.
Do Not subject a WHISPER Differential Pressure sensor to
upstream-downstream pressure differentials exceeding 15 PSID.
While high static pressure will typically not damage the dp sensor, sudden
pressure “spikes” can result in complete failure of the sensor.
A common cause of this problem is instantaneous application of
high-pressure gas as from a snap acting solenoid valve either upstream
or downstream of the meter. If you suspect that your pressure sensor is
damaged please discontinue use of the meter and contact Alicat.