11
Providing Fresh Air in a Contaminated
Environment
If the IQ Express is to be located in a
potentially contaminated environment,
fresh air must be delivered to the Air Port
on the dock for use during instrument
processing. This can be accomplished
either by using a cylinder of “zero air” with
a demand flow regulator (option 1 below)
or by plumbing fresh air into the dock in a
sealed conduit from an outside location
that has known fresh air (option 2 below).
Performing the
fresh air calibration in a contaminated
atmosphere will lead to inaccurate and
potentially dangerous readings. Fresh
air containing 20.9% oxygen and no
contaminants must be provided to the
IQ Express Dock for instrument
processing. If fresh air is unavailable
in the immediate area, steps must be
taken to provide fresh air to the dock.
When a secondary fresh air source (either
gas cylinder or sealed conduit) is used
with two or more IQ Express Docks, a
one-way check valve must be placed in
line between the common section of the
fresh air manifold and each of the docks
to ensure the purity of the fresh air source.
See the section below titled “Fresh Air
Manifold” for further instructions.
Option 1: Using a Gas Cylinder to
Provide Fresh Air to the Dock
A calibration cylinder containing “zero air”,
which contains 20.9% oxygen and no
contaminants may be connected to the
gas port labeled “AIR” to provide fresh air
to the dock for calibration. The cylinder
must be equipped with a demand flow
regulator. The connection from the
cylinder and regulator to the dock may be
made with standard gas tubing.
For single docks, simply connect the “zero
air” cylinder and demand flow regulator to
the dock’s AIR port using standard gas
tubing. A check valve is not necessary
when a cylinder is used to provide fresh
air to a single dock. The fresh air filter is
also not required in this configuration.
For multiple dock setups (up to 8), a one-
way check valve must be placed in the
line between each T-fitting and dock to
ensure the purity of the fresh air source.
See “Multi-Dock Setups with Fresh Air
Manifold” below for further instructions.
The fresh air filter is not necessary when a
gas cylinder is used to provide fresh air to
the dock(s).
Option 2: Using a Sealed Conduit to
Provide Fresh Air to the Dock
Fresh air may also be delivered to the
dock from a known fresh air source via a
sealed conduit that feeds directly from the
source into the AIR port on the dock.
For single docks, install the fresh air filter
as discussed above and simply plumb the
fresh air source directly into the dock’s
AIR port.
For multiple dock setups in which fresh air
is provided to the dock via sealed conduit,
begin by installing the fresh air filter on
each dock. A one-way check valve must
be placed in the line between the t-fitting
in the fresh air manifold and each dock to
ensure the purity of the fresh air source.
See “Multi-Dock Setups with Fresh Air
Manifold” below for further instructions.
Multi-Dock Setups with Fresh Air
Manifold
For more information on this, see
Applications Note # 13-291.
The 54-46-116 manifold is necessary for
use when more than one dock is to be
used with an external fresh air source,
whether it be a cylinder of “zero air” or a
sealed conduit to a fresh air source.
The 54-46-116 manifold is comprised of:
(7) small black T-fittings
(8) clear one-way check valves
(18) pieces of gas tubing 5” long
(1) piece of gas tubing 10” long
