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10.6 Methods of Operating Valves in the ZA8F Flow
Setting Unit
The ZA8F Flow Setting Unit is used as the calibration equipment for a system conforming to System
2. Calibration in such a system is to be manually operated. So, you have to operate the valve of the
Flow Setting Unit each time calibration is made (starting and stopping the calibration gas flow and
adjusting the flow rate).
10.6.1 Preparation Before Calibration
To operate the ZA8F Flow Setting Unit, prepare for calibration as follows:
(1) Check for a complete closing of the zero gas flow setting valve in the unit and open the reducing
valve for the zero gas cylinder until the secondary pressure is [measurement gas pressure plus
approx. 50 kPa, measurement gas pressure plus approx. 150 kPa when a check valve is used]
(300 kPa maximum).
(2) Check that the oxygen concentration of the zero gas and span gas (instrument air 21 vol%O
the cylinder is set for the analyzer.
10.6.2 Operating the Span Gas Flow Setting Valve
The following description is given assuming that instrument air, the same as the reference gas, is used
as the span gas. For more details, see Subsection 7.10.2, "Manual Calibration," earlier in this manual.
(1) When "OPEn" and the "measured oxygen concentration" appear alternately during the span
calibration, open the span gas flow setting valve of the flow setting unit and adjust the flow rate to
600 ± 60 ml/min.
Loosen the lock nut if the valve shaft has a lock nut, and turn the valve regulator slowly
counterclockwise. To check the flow rate, use the calibration flowmeter.
(2) Adjust the flow rate. After the measured oxygen concentration has stabilized, touch the [ENT]
key, then all the digits will flash. Touch the [ENT] key again to display "ZEro Y."
(3) Close the span gas flow setting valve to stop the span gas (air) flow. If the valve shaft has a lock
nut, be sure to tighten the lock nut to prevent any leakage of the span gas into the sensor during
measurement.
10.6.3 Operating the Zero Gas Flow Setting Valve
Operate the zero gas flow setting valve during zero calibration in the following procedures:
(1) When the "OPEn" and the "measured oxygen concentration" appear alternately during
calibration, open the zero gas flow setting valve of the flow setting unit and adjust the flow rate to
600 ± 60 ml/min. To rotate the valve shaft, loosen the lock nut if the valve shaft has a lock nut and
slowly turn it counterclockwise.
(2) To check the flow rate, use an appropriate calibration gas flowmeter.
(3) Adjust the flow rate. After the measured oxygen concentration is stabilized, touch the [ENT] key,
then all the digits will flash. Touch the [ENT] key again to flash "CAL End."
(4) Close the zero gas flow setting valve to stop the zero gas flow. Be sure to tighten the lock
nut if the valve shaft has a lock nut to prevent any leakage of zero gas into the sensor during
measurement. When the stabilization time elapses, the zero calibration will be complete.
10.6.4 Treatment After Calibration
No special treatment of the instrument is needed after calibration. However, it is recommended that
the pressure reducing valve for the zero gas cylinders be closed because calibration is not required so
often.
<10. Other Functions>
10-21
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IM 11M13A01-04E
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