RKI Instruments 30-0951RK LEL - Manual (Page 6)

6 • 30-0951RK LEL Sample Draw Aspirator Adapter
2. The sample draw adapter is normally shipped installed to the detector. If not, screw
the sensor adapter onto the detector and then attach the chamber (with the regulator,
aspirator and flowmeter attached) onto the sensor adapter with the three captive
thumbscrews.
3. Connect a sample line from the area to be sampled to the inlet fitting on the
flowmeter. The fitting accepts 1/4” OD rigid metal tubing such as copper, aluminum
or stainless steel tubing.
4. The aspirator exhaust includes the sample air. It may be routed to a different area
where it can be exhausted safely by installing a tube fitting in the exhaust port of the
aspirator and running tubing to the “safe” area from this port. The port has 1/8 NPT
female threads.
5. Turn the regulator adjustment knob completely counterclockwise and then turn it one
turn clockwise so that the flow will start out at a low level when the compressed air is
connected and turned on.
6. Connect a compressed air source up to a maximum of 300 psi to the inlet of the
regulator. The regulator is only rated up to 300 PSI inlet pressure. Adjust the regulator
adjustment knob so that the flowmeter indicates 3 SCFH. The regulator exhaust
pressure indicated by the regulator gauge will vary for a particular flow depending
on the length of the sample line and other restrictions such as filters. Typically the
pressure will be between 5 and 10 psi for short sample runs. It will be higher for
longer sample runs and if filters are used.
Calibration
1. Follow the instructions in the detector head operator’s manual for setting the zero
reading and making span adjustments.
2. When introducing gas to the detector, fill a gas sample bag with a regulator or
dispensing valve. See “Parts List” on page 7 for available parts.
NOTE: A gas bag is recommended for calibration instead of a demand flow regulator because a
demand flow regulator introduces enough flow restriction to significantly reduce the
flow. If a demand flow regulator is used, the flow will have to be adjusted up to 3 SCFH
while the regulator is connected during calibration and down to 3 SCFH after calibration.
3. Connect the sample bag tubing to the inlet of the flowmeter.
4. Allow the sampe draw adapter to draw gas to flow for 1 minute and then make any
calibration adjustments necessary.
5. Disconnect the sample bag from the flowmeter inlet.