Labconco Class I Enclosure Models 3980423 - Manual (Page 43)

Chapter 6: Maintaining Your Filtered Enclosure
Product Service 1-800-522-7658 39
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
airflows at 90 fpm; 2' (130cfm), 3' (200 cfm, 4' (265 cfm.)
9. Position the aerosol generator discharge in the intake of the baffle inside the
enclosure.
10. Start the aerosol generator (Pressure to be +/- 1 PSIG). Ensure that one Laskin
nozzle is in the “open” position.
11. Allow the generator to operate for a minimum of 15 seconds. For all integral
motorized impeller models, 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.
NOTE: For the Purifier Enclosures ducted to the outside, place the
sampling nozzle in the center of the remote blower exhaust.
Acceptance
Aerosol penetration shall not exceed 0.01 percent measured by the photometer.
Setting the Inflow Face 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 inflow 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 inflow velocity to confirm.
5. Replace the front panel and tighten the screws.