Optical Engine: Maintenance and Cleaning. TSI Quest Quest Environmental Monitor EVM Series, EVM-7

113 Optical Engine: Maintenance and Cleaning

Cleaning PID Sensor

6.

To refit the lamp and electrode pellet properly, it is recommended to twist the lamp into the O-ring of the electrode pellet (twist clock-wise one full turn) ensuring you use a cloth (with no fibers).

7.

Then, lower into the PID sensor as displayed below.

Electrode Pellet and lamp attached

Figure 7-6: Fitting/Inserting the lamp and pellet

8.

Place the plastic Intel-sensor casing over the sensor. Press firmly to snap it into place.

9.

Insert it back into the sensor housing as explained in “Removing and inserting PID sensor”.

10.

After cleaning, you need to perform a zero and span calibration (see PID calibration.)

Optical Engine: Maintenance and Cleaning

The optical engine should be cleaned when the following conditions occur:

 It will not zero

 Exposed to oily or wet mists.

 Readings are falling lower and lower indicating dirty mirror

EVM Series User Manual

114 Optical Engine: Maintenance and Cleaning

Cleaning PID Sensor

To clean the optical engine, this requires the use of a 1/16th Allen wrench and a cotton swab.

 Maintenance and cleaning of the optical engine

1.

Remove the two screws on the optical engine using a Phillips screwdriver.

2.

You have two options when removing the screws:

 Your first option is to loosen the two screws and turn the D-Ring so the flat angle is facing the circular metal plate.

 Your second option is to remove the two screws and D-ring and set these aside.

Screw with D-ring

Mirror on optical engine

Screw with D-ring

Figure 7-7: Optical engine and cleaning

3.

Next, lift the spherical mirror up and off by using a flatheaded screwdriver. Using a clean cotton swab, gently wipe the spherical mirror in a circular motion. Set aside.

4.

Using a clean cotton swab, gently wipe around the outer cavity of the optical engine.

Mirror from optical engine

EVM Series User Manual

115 Optical Engine: Maintenance and Cleaning

Cleaning PID Sensor

5.

For the photodiode (positioned on the bottom of the optical engine), gently wipe around the bottom of the optical engine using a clean cotton swab/cotton ball.

Photodiode

Outer cavity of optical engine

Figure 7-8: Cleaning the optical engine

6.

Place the spherical mirror back over the optical engine. Gently push it into the cavity of the optical engine.

 NOTE: If you loosened the D-ring and screws, ensure the flat side of the D-ring is facing the metal ring as you place it back into place. If you removed the screws and the D-ring, this will not apply.

7.

Tighten down the two screws and D-rings with the Phillips screwdriver.

EVM Series User Manual