Installation 
36  Cary 100/300/4000/5000/6000i/7000 Spectrophotometers User’s Guide 
Pressure regulator and gauge 
Operating pressure is from 83 to 172 kPa (12 to 25 psig). Always use 
an appropriate regulator and gauge to ensure that the nitrogen 
supply is consistently maintained at the correct pressure.  
Supply tubing 
Use clean, flexible plastic (polyvinyl chloride (PVC) or equivalent) 
tubing of 6 millimeter (1/4 inch) internal diameter. Never use rubber 
tubing because it may be treated internally with talc that can be 
blown into the optical system. 
CAUTION 
Never use rubber tubing, because it may be treated internally with talc that can 
be blown into the optical system. 
 
 
Figure 11. The position of flowmeters when purging with nitrogen 
1) Instrument    2) Sample compartment  3) Tubing 
4) Flowmeters    5) Shut-off valves   6) Manifold 
7) Pressure regulator  8) Nitrogen control valve 
Procedure 
You may need to purge the instrument with nitrogen under the 
following circumstances: