Chapter 2, Maintenance
Operation Manual
2-2
GEMINI Twin-Port Sampler
1. Remove the Filter Disc from the Tube Holder by rolling the
flange part of the Tube Holder down and away from the Disc.
2. Gently tap or blow on the surface to remove any foreign matter.
3. Replace the Disc, orienting it so the previously exposed
surface is once again facing away from the Sampler.
Valves
The needle valve stem of each valve can be occasionally
removed for inspection of the needle and the needle seat.
1. Turn the stem counterclockwise until it is free of the valve body.
2. Clean the needle by wiping it with a soft tissue.
3. If the valve seems to be clogged (i.e., you are unable to
achieve 500 ml/min. flow at 3-1/2 to 4 turns open),
remove the pressure plate and Tube Holders. Direct a
stream of compressed air through the open valve body to
help dislodge any particulate matter causing the problem.
4. Reinstall the needle.
Performance Test
After extended idleness and periodically during use, check the
Sampler for proper performance with the following test:
1. Connect a water manometer or vacuum gauge to one of
the Tube Holders.
2. Open the associated needle valve 3 to 4 turns counter
clockwise from fully closed.
3. Connect a flowmeter to the other Tube Holder.
4.
Close (fully clockwise position) the associated needle valve.