Inspecting The Sampling Line; Checking For Leaks; Figure 5-10. Maintenance: Final Dusting - Teledyne T640 User Manual

5.2.7.

INSPECTING THE SAMPLING LINE

5.2.8.

CHECKING FOR LEAKS

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5. Use a can of compressed gas made specifically for electronics to blow any
dust or other debris from the optics chamber, from the cup, from the bottom
of the optics chamber, and from the tubing.

Figure 5-10. Maintenance: Final Dusting

6. When finished, reassemble optics chamber components; reinsert cup to
bottom of optics chamber; reconnect tubing from cup in bottom of chamber to
RH/T sensor and from RH/T sensor to the DFU filter, and reinstall the ASC
support.
7. Close instrument, and perform a PMT sensor check with the SpanDust™
(Section 4.1.4).
Look inside the sampling line for debris or dust on the walls. If needed, push a
rag or a paper towel through the line; then use a can of compressed gas made
specifically for electronics to blow through the line for final cleaning.
The internal components of the T640 are not meant to be under strict vacuum as
what would normally be done in a leak test. So, to avoid damage to internal
components, it is recommended that the inlet never be capped (air tight) while the
instrument pump is running.
The Zero Test is a way to check for leaks that do not involve pulling a vacuum
on the system.
1. Remove the inlet and fit a HEPA filter to the sample port.
2. Observe the PM values on the front panel display.
3. Within a few minutes, the PM values should be at zero.
4. If the PM values are not reading zero, then there may be a leak in the system
above the optical sensor (i.e. from the optical sensor nozzle up to where the
HEPA filter was fitted).

Note, it is also possible the HEPA filter being used is either bad or
leaking. Always have a second filter handy to check.

If the PM values do read zero, then there is not a leak above the optical
sensor.
Teledyne API T640 PM Mass Monitor 60