Untitled - COMEVAL

Unival® BUTTERFLY VALVES
Installation, Start-Up and Maintenance
Data Sheets Manual
#. – START UP
- Before start up, ensure that the material, pressure desing, temperature design, flow direction and other essential parameters are
correct in conformity to the process.
- Ensure that the valve is place in its correct position before tightening the final assembly.
- Observe all local regulations concerning the labour risks and essential safety protection at the plant.
- Temperatures above 50ºC or below 0ºC may cause personnel injures if valves are touched. Ensure that the corresponding warning
signs are displayed in the valve or surrounding site..
- Avoid remains of welding and dirties fl ushing through the system as it would damage the valve seating if trapped between disc
and seat.
# – MAINTENANCE AND REGULAR CHECKING.
Maintenance and corresponding intervals should be defined and scheduled an by the plant operation personnel according to service level.
It is highly recommended to operate the valve at least once a month.
Please review the valve seat surface and the fl ow passage as well as the stem packing.
Always wait the valve medium to cool down before starting any maintenance job at the plant, release the pressure from the system,
drain the line and pipe system in the event of toxic, corrosive, flammable or caustic fluids.
Vale rubber seats are replaceable. However, given the reasonably low cost of the entire valve thanks to the serial and bulk production
it is not economically wise to replace seats in small size valves. Should seats are to be replaced, please get in touch with our
specialised personnel for technical assistance.
#- RECOMMENDED SPARES.
The recommended spares should be defined in view of the installation magnitude, duties, nº of cycles and other usual parameters. As
recommended spares only soft goods such as seat and packing should be kept at the plant. In the long term, spare discs and stems
might also be recommended at user’s choice, however, butterfly valves are highly serialised manufactured items at relatively low cost
thus complete valves might be used as replacement.
# – TROUBLE SHOOTING CHART
SYMPTOM LIKELY REASON CORRECTIVE ACTION
No fl ow Valve disc is closed Open the valve disc
End covers still placed.
Remove end covers.
Little fl ow The valve disc is not open enough. Keep on turning the hand lever or worm gear.
Upstream strainer basket clogged with dirties. Clean / replace the spare basket.
Clogged pipe lines.
Check pipe lines.
Atmospheric Leakage Stem packing seals are damaged or worn down. Remove the valve from the line and place a new one.
Flange rubber facing is scratched or worn down Remove the valve from the line and replace the rubber seat.
Stem jamming, valve out
of order
Working duties are beyond permissible parameters.
(medium, temperature, etc.)
Energy source failure (in case of actuated
valves)
Wrong Rotary movement operation.
Remove the valve and consult factory or the nearest UNIVAL
distributor.
Review the energy source.
Operate rightly. Clock wise to close.
Seat Leakage Valve is not properly closed. Tight the lever firmly without using any wrench.
Excessive Differential Pressure at the system. Check plan design parameters.
Operate the valve with worm gear.
Fluid contaminated with dissolved solids. Clean the valve trim. And place a strainer upstream the valve.
Valve body gets broken. Assembly bolts have been wrongly tighten or
counterflanges are misalign.
Align the pipe and install a new valve in a proper way.
Data subject to change without prior notice
75