Labconco Purifie Horizontal Clean Benches 3970424 - Manual (Page 34)

Chapter 6: Maintaining Your Vertical Clean Bench
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6. Set the valve to “DOWNSTREAM.” Place the palm of your hand over the
sampling port of the pistol. There should be a strong vacuum at this port. If the
vacuum is weak, contact Air Techniques Hamilton Associates.
7. Turn the enclosure on and let it operate for a minimum of 5 minutes.
8. If necessary, adjust the speed control of the enclosure to maintain the following
downflow airflows at 55 fpm; 2' (230cfm), 3' (340 cfm), 4' (460 cfm.)
9. Position the aerosol generator discharge in the intake of the prefilter on top of
the enclosure.
10. Start the aerosol generator (Pressure to be 10 +/- 1 PSIG). Ensure that one
Laskin nozzle is in the “open” position.
11. Allow the generator to operate for a minimum of 15 seconds. Scan the
downstream exhaust side of the HEPA filter by passing the sampling nozzle of
the gun in slightly overlapping strokes over the entire surface the filter, with
the sampling port not more than 1 inch from the surface of the filter media.
Scan the entire periphery of the filter and the gasket between the filter frame
and the enclosure frame. Scanning shall be done at a traverse rate of not more
than 2 inches per second.
Acceptance
Aerosol penetration shall not exceed 0.01 percent measured by the photometer.
Setting the Downflow Velocity with the
Speed Control Adjustment
1. Remove the front panel by loosening the (2) Phillips screws on top that
secure the front panel.
2. The speed control is located on the electrical subassembly located behind
the switched control panel and below the front panel. See Figure 6-1.
3. Adjust the speed control with a small Phillips screwdriver by turning the
screw counterclockwise to increase blower speed or clockwise to decrease
the blower speed. The speed control is very sensitive, so proceed with
caution.
4. Measure the downflow velocity per the averaging technique outlined in
Chapter 3 and adjust the speed control slowly for the desired speed. Allow
the speed to stabilize and re-measure the downflow velocity to confirm.
5. Replace the front panel and tighten the screws.