Installation manual

4. Connect the supply of nitrogen or argon gas to the inlet purge connection or open

inlet purge line. Leave the outlet connection open.

• Exercise caution to avoid introducing dirt, moisture, rust, or other contaminants

into the sensor case.

• If the purge gas is heavier than air (such as argon), locate the inlet lower than the

outlet, so that the purge gas will displace air from bottom to top.

• If the purge gas is lighter than air (such as nitrogen), locate the inlet higher than

the outlet, so that the purge gas will displace air from top to bottom.

5. Make sure that there is a tight seal between the inlet connection and sensor case, so

that air cannot be drawn by suction into the case or purge line during the purging

process.

6. Run purge gas through the sensor.

The purge time is the amount of time required for full exchange of atmosphere to

inert gas. The larger the line size, the greater amount of time is required to purge

the case. See Table 5-1. If purge lines are being used, increase the purge time to fill

the additional volume of the purge line.

Note

Keep the purge gas pressure below 30 psig (2 bar).

Purge timeTable 5-1:

Sensor model Purge rate, in ft

/hr (l/h) Time, in minutes

F025 20 (566) 4 1/2

F050 20 (566) 4 1/2

F100 20 (566) 6

F200 20 (566) 15

F300 20 (566) 25

7. At the appropriate time, shut off the gas supply, then immediately seal the purge

outlet and inlet connections with the purge plugs.

Note

Avoid pressurizing the sensor case. If pressure inside the case elevates above atmospheric

pressure during operation, the flowmeter density calibration will be inaccurate.

8. Make sure that the purge fitting seals are tight so that air cannot be drawn by

suction into the sensor case.

5.2

Pressure ratings for EN-1092 flanges

See Figure 5-1 for pressure ratings for EN-1092 flanges.

Supplementary information

14 Micro Motion F-Series