Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 138)

IM 11M13A01-04E 10-20
(1) Attach the zero gas valves onto the gas cylinder. First, turn the valve regulator of
the zero gas valves counterclockwise to completely retract the needle at the top from
the gasket surface. Maintaining the valve in this position, screw the valve mounting
into the mouthpiece of the gas cylinder. (If screw connection is proper, you can turn
the screw manually. Do not use any tool.) When the gasket comes in contact with the
mouthpiece of the gas cylinder and you can no longer turn it manually, tighten the
lock nut with a wrench.
(2) Remove the carrying case from the standard gas unit. The case is attached to the
unit with six screws. So, loosen the screws and lift them off.
(3) Slide the gas cylinder through the hole in the back of the unit and connect the tube
(the piping in the unit) to the valve connections. Insert each tube at least 10 mm to
prevent leakage, and secure it using a tube clamp.
(4) Attach the gas cylinder to the case. Extend the valve regulator of the zero gas valves
through the hole in the front panel of the unit and secure the bottom of the cylinder
with the clamp.
(5) Take note of the oxygen concentration of the sealed gas indicated on the gas
cylinder and replace the carrying case. Enter the oxygen concentration of the sealed
gas using the parameter code B01 as a zero-gas oxygen concentration. Also check
that no piping is disconnected.
Thus, the work of installing a gas cylinder is completed. However, gases in the cylinders
cannot immediately flow out after these procedures. To discharge the gases, it is
necessary for the needle in the zero gas valves to puncture a hole in the gas cylinder (see
Section 10.5.3).
10.5.3 Calibration Gas Flow
<Preparation before calibration>
(1) To operate the standard gas unit, place it on a nearly horizontal surface in order to
allow the flow check to indicate the precise flow rate. In addition, a power supply for
driving the span gas (air) supply pump is required near the unit (the length of the
power cord attached to the unit is 2 m). Select a suitable location for the unit near
the installation site of the converter.
(2) Connect the tube connector port of the standard gas unit to the calibration gas inlet
of the detector, using a polyethylene resin tube with an outside diameter of 6 mm. Be
careful to prevent gas leakage.
(3) Fully open the needle valve mounted on the calibration gas inlet of the detector.
(4) Enter the oxygen concentration of the sealed gas (noted from the cylinder) into the
converter. Also check that the oxygen concentration of the span gas is correctly set
(21 vol% O
2
for clean air). When using the ZO21S Standard Gas Unit (for use of the
atmospheric air as a span gas), use a hand-held oxygen analyzer to measure the
actual oxygen concentration, and then enter it.
<Flow of span gas (air)>
The standard gas unit is used only when manual calibration is employed.
Therefore, the timing for flowing span gas (air) is included in the manual
calibration flowchart described in Section 7.10.2, earlier in this manual. For
operation of the converter, see Section 7.10.2.
(1) When the “OPEN” and “the measured oxygen concentration” are alternately
displayed during calibration, plug the power cord into the power supply
socket to start the pump of the standard gas unit.