21
Gilian
®
GILAIR-3 & GILAIR-5 AIR SAMPLING SYSTEMS
Sensidyne Document No. 800880M (Rev E)
SECTION THREE
FLOW OPERATION
3.1
LOW FLOW OPERATION
3.1.1
Description
The GilAir-3/GilAir-5 Sampling System offers two
modes of low-flow sampling Constant Flow and Multi-
flow. In each case the appropriate module is fitted to
the top of the sampler and communicates with the
pump through the opening beneath the top insert
plate. Both the Constant Flow and Multi-flow modules
are equipped with an On/Off switch control allowing
these units to be functionally engaged or disengaged
without physical removal from the sampler. The mod-
ules incorporate a luer taper port which is used for bag
sampling.
3.1.2
Constant Low Flow
The Constant Low Flow Module is suitable for sampling
between 5 and 500 cc/min , and will maintain a con-
stant low flow through the sampling head (i.e., tube
holder) despite changes in load - the maximum load
being 25” H
2
O. The device utilizes an internal pressure
regulator to maintain a constant pressure drop and
hence a constant flow, through an externally adjustable
flow control valve discharging to atmosphere. Since the
discharge flow is maintained constant and the sampling
system is otherwise closed, the inlet flow must remain
constant as well. However, the flow constant in this
mode is termed “flow stabilized” and will not activate
the flow fault function should the flow deviate beyond
±
5%.
3.1.3
Constant Low Flow Module
NOTE
Installation or removal of any low flow module must be
done in a clean environment while the sampler is turned
off. Contamination of the air passages between the pump
and the low flow module may result in a failure of the
system.
Make sure the O-ring seals of the low flow module are
properly seated into the top of the pump assembly and
that the mating boss clears the case opening prior to se-
curing the mounting screws. Use a flat screwdriver to
engage the notch in the module’s On/Off control as
shown. With the Module in the Off position, turn the
sampler On and adjust the flow to between 1.0 and 1.5
LPM using the flow adjust pot. Switch the Module On
and using a fine screwdriver, engage the flow control
valve through the access hole. Note that the sampler’s
built-in rotameter will not be useful at flows below 500
cc/min, an external flow measuring device, such as a
Gilibrator 2 or calibrator rotameter, must be used. The
system’s performance should be checked by applying a
load of 20-25” H
2
O and verifying that the flow recovers
to within
±
5%. Note that at very low flow rates it may
take several minutes for the flow to recover. This is
normal.
3.1.4
Bag Sampling
The module is provided with an internal luer taper for
bag sampling. Bag sampling is accomplished by attach-
ing a piece of tubing from the sampling bag to the boss
opposite the luer taper end (luer taper to 1/8” ID tub-
ing). Install the luer taper fitting into the luer taper re-
ceptacle on the top of the module. Flow is adjusted by
means of the same screw used to set low flow. Flow
measurements can be taken via the inlet boss of the
pump. The unique feature of this system is that it will
automatically shut the flow off when the bag has been
filled. The maximum pressure within the bag is ap-
proximately 8” of water.
Summary of Contents for GILAIR-3
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