4.1
DISaSSEMBLy aND CLEaNING PROCEDURE
The PIRVOL should be inspected periodically to
ensure that its performance is not impaired by fouled
optics or by clogging of the sample draw cup or
hydrophobic screen. Inspection and/or periodic
maintenance involves three different areas.
IMPORTANT
Remove power before disconnecting and
removing the PIRVOL for maintenance.
Sample Draw Cup.
Perform a visual inspection of
the sample draw cup and associated plumbing, and
clean as required. External filtration of sample stream
is recommended.
hydrophobic Screen.
The flow of gas through the
screen can be inhibited by an accumulation of mud
or other contaminants. To inspect the hydrophobic
screen, disassemble the PIRVOL as described below.
If the screen appears to be fouled, replace it.
Optics.
Cleaning of the optical surfaces is required
only if an optical fault is indicated (1.0 milliampere
current output signal from the PIRVOL). This
procedure is most easily accomplished on a bench.
Required materials: Clean, flat work surface,
foam tipped swabs (no cotton), isopropyl alcohol,
screwdriver.
CAUTION
The PIRVOL contains semiconductor devices
that are susceptible to damage by electrostatic
discharge. An electrostatic charge can build
up on the skin and discharge when an object is
touched. Therefore, use caution when handling
the device, taking care not to touch electronic
components or terminals. If the electronics
assembly is removed, it should be placed in an
anti-static bag or box while stored or transported.
A static safeguarded work area is highly
recommended (if available) for disassembly and
cleaning of the PIRVOL.
1. Remove the sample draw cup from the front of the
PIRVOL. See Figure 12.
2. Perform a visual inspection of the sample draw
cup and associated plumbing, and clean as
required. Also inspect the two O-rings inside the
sample draw cup and clean, lubricate or replace
as required.
3. Loosen the two captive screws on top of the
mirror assembly (Figure 12) and remove the
mirror assembly and hydrophobic screen from the
electronics assembly.
4. Thoroughly douse the interior of the mirror
assembly as well as the foam tipped swab
with isopropyl alcohol. Use the swab to gently
cleanse the surfaces of the reflecting mirrors
inside the mirror assembly. After cleaning with
the swab, flush out the mirror assembly using
a liberal amount of isopropyl alcohol. Tip the
mirror assembly with mirror openings downward
to remove accumulated isopropyl alcohol and
particle contaminants. Repeat the alcohol flush
to remove any remaining contaminants. Allow the
mirror assembly to air dry in a dust-free location.
IMPORTANT
Do not insert any sharp object into the mirror
assembly. Scratching of the mirrors will void
the PIRVOL warranty. Do not use cotton tipped
swabs or buds as they are likely to leave fiber
residue.
5. Clean the two windows on the electronics
assembly using the procedure described above.
When the mirror assembly and electronics
assembly are thoroughly dry, proceed with re-
assembly.
6. Slide a new hydrophobic screen over the end of
the mirror assembly, then carefully seat the mirror
assembly and hydrophobic screen against the
base of the electronics assembly. Be careful not
to crumple or fold the hydrophobic screen.
7. Tighten the two captive screws on the top of the
mirror assembly. Tighten the screws evenly. Do
not over-tighten (6 inch-pounds recommended).
8. Slide the sample draw cup back onto the PIRVOL.
9. Check for leaks around the PIRVOL sample draw
cup.
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