cashco 521 Panduan Pemasangan, Pengoperasian & Pemeliharaan - Halaman 4
Jelajahi secara online atau unduh pdf Panduan Pemasangan, Pengoperasian & Pemeliharaan untuk Unit Kontrol cashco 521. cashco 521 20 halaman. Total tfe, globe-pattern control valve body iom
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C. Auxiliary Detection:
1. When a fluid is known to permeate TFE over
a finite time period and the fluid is lethal
or is subject to stringent limits of fugitive
emis sions, the vented pipe plug (12) should
be removed and one of, or a com bi na tion of,
IV. STARTUP
A. General:
1. Ensure that the Model 521 unit has been
properly adjusted and calibrated, including
the po si tion er, if in stalled.
2. Recommend startup to be in "manual"
mode. This procedure assumes double
block (iso la tion) and bypass valves for the
"control valve station" per Figure 1.
3. Start with either of the two block valves
closed, with the other open. The bypass
valve should be closed. Pres sur ize system
if possible/prac ti cal.
4. Back out the airset's adjusting screw until
loose.
5. Turn on air supply pressure.
6. Adjust the air supply airset (filter-regulator) to
the proper level as indicated in the technical
bulletin 521-TB. DO NOT STROKE THE
CON TROL VALVE WITH AN AIR SUPPLY
PRESSURE SET TING GREATER THAN
REC OM MEND ED MAX I MUM PRESSURE!
7. Place loop controller into "manual" mode.
Vary setting from minimum – mid-range—
maximum SIG out put. Ob serve response of
control valve unit to these changes of input
SIG. The valve should fully stroke at the
variation from minimum SIG to maximum
SIG; the mid-range SIG should have the
valve stem travel at/near 1/2 open.
8. Confirm that action of controller and
po si tion er – direct or reverse – are producing
the desired response in the control unit.
Confirm that the control valve "fail" position
is as re quired.
4
the following methods should be considered
to monitor the integrity of the internal primary
stem (9) seal – the bellows sub-assembly
(8):
SECTION IV
9. Hereafter, the procedure assumes that
actual fluid flow may be established. This
may not be practical/pos si ble in all cases;
if so, vary pro ce dure as required.
Always "heat" or "cool" down the system
pip ing SLOW LY by opening the control valve
station bypass valve in small increments.
10. With one of the control valve station block
valves still closed, and the loop controller
still in "man u al" mode, open bypass valve
and vary flow rate manually to observe the
re sponse of the controller and control valve
unit to geth er.
11. Attempt to develop manual control of the
loop by opening/closing the manual bypass
as required, or by manually controlling
main stream flow as required.
12. When the control valve is partially open,
crack open, slowly, the closed block valve
while si mul ta neous ly clos ing the bypass
valve; it may be necessary/desirable to
vary the man u al output SIG from the
controller si mul ta neous ly also. Continue
this procedure until the by pass is closed
and the block valves are both fully open.
The system is still under "manual" mode
control, but all flow is passing through the
control valve.
DO NOT WALK AWAY AND LEAVE A MANUALLY
CONTROLLED CONTROL VALVE UNATTENDED!
13. Vary controller "manual" SIG output until
match ing the "automatic" SIG output, then
change the mode of the controller over to
"automatic", and the loop will ex pe ri ence a
minimum of upset conditions, and will be in
automatic control.
a. gas detector with alarm
b. pressure indicating gauge
c. pressure switch with alarm
d. inert gas, constant flow purge.
CAUTION
IOM-521