Form 37714 Rev 1809
Page 6 of 13
Low Flow Applications (Cont)
Using a CPC and Dual, Tri, or Quad Adjustable Low Flow Tube Holder (Figure 3)
Set/Calibrate Flow Rate for Multiple Tubes
• Requires Constant Pressure Controller (CPC) and Adjustable Low Flow Tube Holder (see Accessories). The low
fl
ow tube holder used with CPC
allows up to four tube samples to be taken simultaneously, each at different
fl
ow rates if desired.
• Allow pump to equilibrate after moving it from one temperature extreme to another.
• Charge pump battery completely before calibration and sampling.
• Calibrate/verify
pump
fl
ow rate before and after each sampling operation using the tube holder and pump to be used for sampling.
• Set
the
fl
ow rate through the pump
fi
rst and then calibrate the
fl
ow rate through each representative sorbent tube.
Pump Flow Rate
Follow these important steps before proceeding.
1. Ensure that the ba
tt
ery is fully charged and that the pump has run for 5 minutes before calibrating. Leave pump running.
2. Prepare a calibrator
(see calibrator instructions)
. Using
fl
exible tubing, connect the calibrator outlet (suction port) to the pump inlet.
3. Calculate the sum of all tube
fl
ow rates. The maximum
fl
ow rate through any one tube is 500 ml/min.*
a. If the sum is
≤
1000 ml/min, set the pump
fl
ow rate to 1.5 L/min.
b. If the sum is > 1000 ml/min, multiply that number by 0.15 and total the two numbers. Set the pump
fl
ow rate for the resulting
new sum. (
Example:
Sampling with three sorbent tubes, each with a
fl
ow rate of 500 ml/min.* The sum of the tube
fl
ow rates is
calculated as 3 x 500 = 1500. Determining a 15% higher
fl
ow rate is calculated as 1500 x 0.15 = 225. Calculating the
fi
nal pump
fl
ow se
tt
ing would be 1500 + 225 = 1725 ml/min.)
* Back pressure across some sample tubes can be higher than average. In these instances, the maximum
fl
ow rate of 500 ml/min per tube may not
be achieved.
4. Using a small screwdriver, turn the
fl
ow adjustment screw on top of the pump
(Figure 1)
(
clockwise
to increase
fl
ow or
counterclockwise
to decrease
fl
ow) until the calibrator indicates the required
fl
ow rate.
5. Remove tubing from the pump inlet and calibrator outlet.
Figure 3.
Quad Adjustable Low Flow Tube Holder
Top view of
fl
ow
adjust screws
Anti-tamper cover
Low
fl
ow holder outlet
Sorbent sample tube
Rubber sleeve
Clothing clip
Flow adjust screws
Protective cover
