8
Setting or Verifying the Flow Rate
For Low Flow Sampling (5 to 500 ml/min)
(Requires optional Constant Pressure Controller (CPC) and Adjustable Low
Flow Tube Holders - see Low Flow Adapter Kit in Optional Accessories.) See
Figure 2.
The Constant Pressure Controller (CPC) accessory, Cat. No. 224-
26CPC-10, is used as a pressure regulator to maintain a constant
10 inches water back pressure for low flow sampling. The CPC is
used in conjunction with an Adjustable Low Flow Tube Holder
(Cat. Nos. 224-26-01, -02, -03, or -04) for single or multiple-tube
sampling.
Set the flow rate at approximately 1.5 L/min.
(See Setting Flow Rate
for High Flow Sampling,
page 7.)
For multiple-
tube sampling, the
flow rate must be
greater than the sum of
the required flow rates
through all the tubes.
With a short length of
Tygon
®
tubing, connect
the pump inlet to the
CPC outlet (the side of
the CPC without a label),
(Figure 2). Connect the
inlet side of the CPC
(marked “to sample”) to
the Adjustable Low Flow
Tube Holder (Figure 2).
Label all tubes and
ports. Insert opened
representative tubes
into the rubber
sleeves of each port
on the Adjustable Low Flow Tube Holder. If any port remains
unused, place an unopened tube in it; it is important to “seal”
unused ports.
Use tubing to connect the exposed end of one tube to a primary
standard flowmeter. Loosen the screw on the low flow holder
port. Turn on the pump using the on/off button (Figure 1, #8),
and calibrate flow. Turn the brass screw (needle valve) on the
Adjustable Low Flow Tube Holder (Figure 2) until the flowmeter
matches the desired flow rate. For multiple-tube sampling, repeat
this procedure for each port to calibrate the flow rate for each
tube. Seal unused ports.
Do not adjust the flow on the pump. Adjust flow by using the
brass screw on the Adjustable Low Flow Tube Holder.
2
cont’d
continued on page 9
Collar Clip
Protective
Cover for
Sample Tube
Flow Adjustment
Screw (needle
valve)
Adjustable Low
Flow Tube Holder
Constant
Pressure
Controller (CPC)
Tygon Tubing
"To Sample" Label
Figure 2
Configuration for Low Flow Sampling
