Installing Gas Cylinders; Calibration Gas Flow - YOKOGAWA ZR22G User Manual

10.11.2

Installing Gas Cylinders

Each ZO21S Standard Gas Unit comes with six zero gas cylinders including a spare. Each
gas cylinder contains 7-liters of gas with a 0.95 to 1.0 vol%O2 (concentration varies with each
cylinder) and nitrogen, at a pressure of 700 kPaG (at 35°C).
The operating details and handling precautions are also printed on the product. Please read them
beforehand.
To install the gas cylinder, follow these steps:
(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, following
instructions on the converter display. 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 10.7.3).
10.11.3

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 stop 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%O2 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 feeding span gas (air) is included in the manual calibration flowchart described in Section
"7.12.2 Manual Calibration". For operation of the converter, see Section "7.12
(1) When the message "Open span gas valve" is displayed on the converter display during
calibration, plug the power cord into the power supply socket to start the pump of the
standard gas unit.
<10. Other Functions>
Calibration".
IM 11M12G01-02EN 1sh Edition : Mar. 25, 2021-00
10-37