YOKOGAWA EXAxt ZR22G, User Manual, Page: 72 / 211

<4. Piping>
4-7
IM 11M12A01-02E 16th Edition : Mar. 19, 2020-00
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Stop valve or Check valve
Piping for the calibration gas, 6 mm (O.D.)
by 4 mm (I.D.) Stainless steel pipe
Piping for the reference gas, 6 mm (O.D.)
by 4 mm (I.D.)Stainless steel pipe
Figure 4.8 Piping for the Calibration Gas Inlet
4.2.3 Piping for the Reference Gas
Reference gas piping is required between the air source (instrument air) and the flow setting unit,
and between the flow setting unit and the detector.
Insert the air set next to the flow setting unit in the piping between the air source and the flow
setting unit.
Use a 6 mm (O.D.) x 4 mm or larger (I.D.) (or nominal size 1/4 inch) stainless steel pipe between
the flow setting unit and the detector.
4.2.4 Piping to the High Temperature Probe Adapter
Refer to Section 4.1.4 for the piping.
4.3 Piping for System 3
Piping in System 3 is illustrated in Figure 4.10. In System 3, calibration is automated;
however, the piping is basically the same as that of System 2. Refer to Section 4.2.
Adjust secondary pressure of both the air set and the zero gas reducing valve so that these
two pressures are approximately the same. The flow rate of zero and span gases (normally
instrument air) are set by a single needle valve.
After installation and wiring, check the calibration contact output (see Sec. 7.11.2), and adjust
zero gas reducing valve and calibration gas needle valve so that zero gas flow is within the
permitted range. Next check span gas calibration contact output and adjust air set so that span
gas flow is within the permitted range.
CHECK
OUT
ZERO GAS IN
AIR IN
Instrument air Approx.
1.5 l/min.
Flowmeter
Flowmeter
REF
OUT
*2 *2
EV1 EV2
Solenoid valve
EV1, EV2
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*2: Needle valve is supplied as accessory with flowmeter
Figure 4.9 Piping inside in System 3