RKI Instruments Digester Gas Monitor - Manual (Page 36)

30 • Making Fitting Connections Digester Gas Monitor Operator’s Manual
4. Before tightening the nut, be sure to hold the fitting still from the outside so it does not
rotate using a 5/8 inch open-end wrench or an adjustable wrench (see Figure 17).
While holding the fitting still, firmly tighten the nut with a 9/16 inch open-end wrench or
an adjustable wrench so the ferrules crimp onto the sample tubing and make a seal.
5. Connect the other end of the tubing coming from the compressed air inlet fitting to the
filter/water trap exhaust. Be sure that the arrow on the top of the filter/water trap is
facing toward the compressed air inlet fitting. Use a 5/8 inch open-end wrench or an
adjustable wrench to hold the filter/water trap still and use a 9/16 inch open-end
wrench or an adjustable wrench to firmly tighten the nut so the ferrules crimp onto the
tubing and make a seal.
Figure 18: Compressed Air Filter/Water Trap
6. Install the desired length of 1/4 inch OD rigid metal tube from the compressed air
source into the tube nut and ferrules on the other side of the filter/water trap. Use a
5/8 inch open-end wrench or an adjustable wrench to hold the filter/water trap still and
use a 9/16 inch open-end wrench or an adjustable wrench to firmly tighten the nut so
the ferrules crimp onto the tubing and make a seal.
7. The filter/water trap is self-draining. If the Digester Gas Monitor is not installed in an
area where the water trap can drain onto the ground, install a length of 1/8 inch ID
tubing onto the barb fitting on the bottom of the filter/water trap and route it to a
bucket.
8. The Digester Gas Analyzer uses a maximum of 63 liters of compressed air per cycle
when the maximum allowable tubing lengths are installed. The minimum regulator
output pressure required when no sample lines are installed is 25 PSI. The minimum
regulator output pressure required when the maximum recommended sample line
lengths are installed is 45 PSI. The maximum compressed air supply pressure is 140
PSI. Be sure that your compressed air source has sufficient capacity, sufficient
pressure, and be sure that the compressed air sample is clean and/or filtered.
Connect the compressor line to the rigid tubing coming from the compressed air filter/
water trap.
Hold Still (5/8 inch)
Nut (9/16 inch)
1/4 inch O D rigid met al
tubing f rom compresse d
air inlet f itt ing o f Digester
1/4 inch O D rigid
me tal t ubin g to
compresso r line