Ashcroft 80-81 - Isolation Rings - Manual (Page 10)

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C. Loosen flange bolts securing the isolation ring assembly to the process pipe flange.
D. Upon separation of pipe flanges, remove assembly and flange gaskets from the piping.
In the event only instrument removal is required, use a wrench to unthread the instrument. Use container to
catch the fill fluid when draining from the isolation ring.
PRODUCT MAINTENANCE / IN-SERVICE REPLACEMENT
The following provides the user with th necessary instructions to service this product. This will allow the
customer to perform routine maintenance that may involve in-service instrument replacement.
IN-SERVICE INSTRUMENT REMOVAL / REPLACEMENT (Dependent upon type of assembly connection
listed below)
1) Direct Mount Instrument Removal: Measuring instrument should never be removed from the isolation
ring while in service. For instrument replacement, complete removal of the isolation ring assembly from
service is required.
2) Needle Valve Instrument Removal Option:
a) Shut down process and fully vent/relieve pressure to the assembly. While it is possible that pressure
may be retained in the process when the instrument is removed, it is imperative that the process pres-
sure MUST be at Zero (0 psi) when reinstalling the replacement instrument.
IMPORTANT: Residual pressure may cause potential injury/damage, and replacing an instrument with
residual pressure could result in fill fluid imbalance, thereby causing accuracy errors.
b) Using a flathead screwdriver, turn the adjustment on the needle valve until fully closed (clockwise).
c) Secure the needle valve body using a ¾˝ wrench, and remove the attached measuring instrument (e.g.
gauge, switch, transducer) with a second wrench applied to the instrument’s wrench flats.
d) Position and secure the measuring instrument so that the pressure port is facing upwards. Then utilizing
an ordinary syringe, fill the internal cavity of the process connection with compatible fill fluid. Place finger
on the port and tilt side-to-side to dislodge any trapped air. Continue filling until air bubbles no longer
appear. Note: Improper fill can result in accuracy errors or damage to the flexible isolation ring liner.
Highly viscous fill fluids may require 10 to 15 minutes until air has been completely dislodged.
e) Apply Teflon tape or sealant to instrument fitting while unit is still upside down and place aside while
retaining this position.
f) Pour fill fluid into instrument until fill fluid is overflowing.
g) Using the flathead screwdriver, open the needle valve. Fill needle valve port until fluid is overflowing.
h) Once steps e, f and g have been completed, take the filled measuring instrument and quickly “flip” over
to install (thread) into the top port of the needle valve. This needs to be performed to lose as little fill
fluid as possible.
i) Secure both instruments utilizing the two wrenches previously used for disassembly.
3) Safe Quick Release (SQR) Option: This option provides the end-user with a flexible approach to
remove/replace an existing instrument once the isolation ring has been installed. Prior to removal, it will
be necessary to obtain a pre-filled instrument to allow continued operation and limit downtime. RECORD
the product model number and pressure at which the instrument has been removed; this is important as
it ensures that an exact replacement is “pre-charged” at the factory to retain accuracy. Safe Quick
Release (SQR) removal procedure is as follows:
a) Ensure process pressure has been relieved to the proper intended removal pressure of <300 psi.
Recommended removal/replacement of product is Zero (0 psi).
b) Twist the instrument so that the coupling sleeve-relief lines up with the sleeve-lock key.
c) While holding the instrument securely, pull sleeve downward to disengage coupling.
d) Place newly “pre-charged” instrument on the coupling and pressure downward to engage the coupling.
STORAGE
Store in a cool, dry area.
7 - PRODUCT
MAINTENANCE /
IN-SERVICE
REPLACEMENT
8 - STORAGE
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