cashco 987 Manual de instalación, uso y mantenimiento - Página 10

Navegue en línea o descargue pdf Manual de instalación, uso y mantenimiento para Unidad de control cashco 987. cashco 987 15 páginas. Globe-style pneumatic control valve body iom

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NOTE: Secure the actuator stem (6) by the
flats when rotating the travel stop nut.
NOTE: "Stroke" length is in di cat ed on the
name plate (40), and is the dis tance be tween
the "C" and "O" marks of the indicator plate.
NOTE: The proper calibration of the ac tu a tor/
valve unit will occur when at the upper pressure
level of bench setting, the valve plug (4) will
be in the "C" po si tion. At the lower level of
VII. TROUBLE-SHOOTING GUIDE
1.
Valve is "jumpy" in stroking
A.
Excess packing friction.
B.
Installed backwards.
2.
Valve makes "screeching" noise.
Possible Cause
A.
Excess pressure drop.
B.
Bushing wear.
C.
Misalignment.
3.
Valve exhibits "excess" vibration.
Possible Cause
A.
Excess pressure drop.
B.
Bushing wear.
C.
Excessive cavitation in liquid service.
D.
High outlet velocity.
10
Possible Cause
bench set the actuator pressure should be
within ± 8% of the lower bench setting for the
designed stroke length.
12. Release all pres sure from actuator.
SECTION VII
A1.
Realign body–stem–actuator.
A2.
Packing follower too tight.
A3.
Install Positioner.
A4.
Increase bench.
B.
Install per fl ow arrow.
A.
Bring pressure drop within design limits.
B.
Replace bushing and stem.
C.
Realign body-stem-actuator.
A.
Bring pressure drop within design limits.
B.
Replace bushing and stem.
C1. Change operation parameters to relieve causes
of cavitation.
C2. Replace valve with valve equipped for cavitation control.
D1. Reduce fl ow rate and/or pressure drop.
D2. Use multiple valves in series or in parallel.
D3. Increase outlet pipe size.
Remedy
Remedy
Remedy
IOM-987