FLK Gas Sampling System - MPIP - Free

Siemens
SQ252 Electrically Heated Dedusting Filter
4. Maintenance
4.1 General information
With automatic cleaning using compressed air no regular work is needed by the user. However, checks for any damage and
external soiling should be made in conjunction with other maintenance work and remedied if necessary.
4.2 Leakage test
4.2.1 Pressure test
This test is always required after mounting as well as installation and removal of the filter head.
• Seal off absolutely tight the measuring gas input to the filter (a blank plug can be used for this).
• It is sufficient for a short test when using the valve combination to start the flushing and observe whether compressed
air escapes anywhere on the filter.
Note: With small leaks it is recommended that leak-seeking spray or soap solution is applied to the joints to
localise any leaks.
• This opportunity can also be used to test the joints on the measuring gas line up to the four-way valve.
• Any leaks which are found should be rectified.
4.2.2 Low pressure test
Since the filter is normally under negative pressure in operation, a sealing test under negative pressure is more conclusive.
• Close off the measuring gas input on the filter as under 4.2.1.
• Connect a low pressure measurement sensor as close as possible to the filter output. Ensure absolute sealing tightness!
• Produce a negative pressure of about 300 mbar by switching on the measuring gas pump.
• Shut off the line. The low pressure must now remain almost constant (pressure drop in 5 minutes max. 2 mbar).
• Localise any leaks and rectify them.
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