Butterfly valves Fault diagnosis - WordPress.com · 17|Butterfly valves | Fault diagnosis Findings...
Transcript of Butterfly valves Fault diagnosis - WordPress.com · 17|Butterfly valves | Fault diagnosis Findings...
© InterApp AG | www.interapp.net
Butterfly valvesFault diagnosisInterApp AGApril 2017 / H. Bayrhuber / O. Notz
© InterApp AG | www.interapp.netButterfly valves | Fault diagnosis2 |
Index
• Valve control
• Piping installation mistakes
• Valve installation mistakes
• Operating failures
© InterApp AG | www.interapp.net
Operating failures
Water hammer
Findings Valve not operating
Explanation /Avoidance
Deformation or breaking of shaft and disc
Water hammer can be avoided by closing thevalves slowly by means of gear boxes(instead handlevers) and air flow regulators onpneumatic actuators
Non-synchronized pump start and valveoperation as well as trapped air in the pipingcan create water hammer. Use air relief andpressure relief valves or bursting discs
TroubleshootingReplace the valve
Install suitable devices
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Butterfly valves | Fault diagnosis3 |
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Valve installation mistakes
Valve disc jammed, additional rubber gasket in use
Findings Valve not operating
Explanation /Avoidance
Never use additional rubber gaskets
Additional rubber gasket increases the volumeof rubber around the disc
Torque increases!
Troubleshooting
Dismount valve from pipe
Remove gaskets
Replace damaged parts
Butterfly valves | Fault diagnosis4 |
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Valve installation mistakes
Valve disc jammed, additional rubber gasket in use
Butterfly valves | Fault diagnosis5 |
Findings Shaft end twisted or broken
Explanation /Avoidance
Never use additional rubber gaskets
Additional rubber gasket increases the volumeof rubber around the disc
Torque increases!
Troubleshooting
Dismount valve from pipe
Remove gaskets
Replace damaged parts
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Valve installation mistakes
Valve disc jammed, liner displaced from body groove
Butterfly valves | Fault diagnosis6 |
Findings Valve not operating
Explanation /Avoidance
Ensure enough space during inserting valvebetween flanges.
Troubleshooting
Dismount valve from pipe
Replace damaged liner
Install valve ensuring enough space betweenflanges.
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Valve installation mistakes
Valve disc jammed, liner displaced from body groove
Butterfly valves | Fault diagnosis7 |
Findings Shaft end twisted or broken
Explanation /Avoidance
Ensure enough space during inserting valvebetween flanges.
Troubleshooting
Dismount valve from pipe
Replace damaged liner
Install valve ensuring enough space betweenflanges
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Piping installation mistakes
Valve disc jammed due to too small inside diameter of flanges
Butterfly valves | Fault diagnosis8 |
Findings Valve not operating
Explanation /Avoidance
Consider Installation & Maintenance Manualof valve
Consider disc hits the piping flange, especiallywhen installing in plastic piping
TroubleshootingCheck valve disc edges, replace if damaged
Reinstall valve using chamfered stub flanges
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Piping installation mistakes
Valve disc jammed due to offset mounting between flanges
Butterfly valves | Fault diagnosis9 |
Findings Valve not operating
Explanation /Avoidance
Consider Installation & Maintenance Manualof valve
Consider dics hits the piping flange
Ensure proper centering of valve betweenpipe flanges
TroubleshootingCheck valve disc edges, replace if damaged
Reinstall valve properly centered
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Piping installation mistakes
Missaligned piping or flanges not parallel
Butterfly valves | Fault diagnosis10 |
Findings Valve leaking on pipe flange
Explanation /Avoidance
Missaligned piping creates unevencompression of liner on flange surface
Ensure proper allignement of pipe and flange.
Troubleshooting
Dismount valve, check liner and replace ifdamaged
Refit the piping
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Piping installation mistakes
Sealing surface of counter flange
Butterfly valves | Fault diagnosis11 |
Findings Valve leaking on pipe flange
Explanation /Avoidance
Not smooth surface creates unevencompression of liner on flange surface
Troubleshooting
Dismount valve, check liner and replace ifdamaged
Refit the piping
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Piping installation mistakes
Use of flanges with too big inside diameter
Butterfly valves | Fault diagnosis12 |
Findings Valve leaking in flow direction
Explanation /Avoidance
To achieve maximum pressure rate of thevalve a correct compression of liner ismandatory
Consider Installation & Maintenance Manualof valve.
Troubleshooting Use flanges with correct inside diameter
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Piping installation mistakes
Insufficient compression of liner downstream
Butterfly valves | Fault diagnosis13 |
Findings Valve leaking in end of line use
Explanation /Avoidance
To achieve maximum pressure rate of thevalve a correct compression of linerdownstream is mandatory
Consider Installation & Maintenance Manualof valve
Troubleshooting Use correct counterflange downstream orreduce pressure to next lower pressure class
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Piping installation mistakes
Flange bolts too long or too high tightening torque
Butterfly valves | Fault diagnosis14 |
Findings Broken body on LUG type
Explanation /Avoidance
Too long bolts splits the lugs of the body
Too high bolt tightening torque damages thethreads
Troubleshooting
Replace the valve
Use correct screw length
Refere to tightening torque table of screwprovider
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Piping installation mistakes
Use of U-section body as flanged body type
Butterfly valves | Fault diagnosis15 |
Findings Broken flange on U-section body
Explanation /Avoidance
When used as flanged body type, U-sectionbody requires flat face flanges
Tightening raised faced flanges bend or breakthe flange of valve body
Refer to Installation & Maintenance Manual ofvalve
TroubleshootingReplace the valve
Install valve with passing through bolts or useflat faced flanges
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Valve control
Too low air supply pressure and flow
Butterfly valves | Fault diagnosis16 |
Findings Valve is slamming when opening
Explanation /Avoidance
Power to operate the actuator insufficient
Actuator selection has to consider theavailable air supply pressure
Orifice of air supply system to small
Use air flow regulators on exhaust ports ofsolenoid valve
Troubleshooting
Increase air supply pressure and/or orifice ofall air supply system
Install air flow regulators
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Valve control
Working conditions not considered
Butterfly valves | Fault diagnosis17 |
Findings Valve is slamming when opening
Explanation /Avoidance
Temperature influences hardness of rubberliners, torque might increase
Consider severe conditions for actuatorselection
TroubleshootingUse correct actuator
Increase air supply pressure on pneum.actuators
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Valve control
Chemical attack on liner
Butterfly valves | Fault diagnosis18 |
Findings Valve is slamming or not opening
Explanation /Avoidance
Incorrect selection of rubber material leads toswelling of liners
Refer to ValveFinder, material resistancecharts or ask technical support
Troubleshooting Replace liner or valve considering the workingand fluid condition
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Valve control
Too high working temperature
Butterfly valves | Fault diagnosis19 |
Findings Valve is slamming or not opening
Explanation /Avoidance
Rubber liners are hardening and torqueincreases
Use liners within specified temperature range
Select liner to effective working temperature
Troubleshooting Replace liner or valve considering the workingand temperature condition
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Valve control
Power and air supply?
Butterfly valves | Fault diagnosis20 |
Findings Valve is not operating
Explanation /Avoidance
Air supply at the actuator missing or air supplypressure too low
Sizing of solenoid valve and / or air supplypiping too small for size of actuator
Power supply missing or wrong voltage
Troubleshooting
Ensure that air supply pressure is according tospecification
Use a bigger solenoid valve and / or air supplypiping according to Installation Manual
Use the correct voltage
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Valve control
Solenoid valve in manual mode
Butterfly valves | Fault diagnosis21 |
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Findings Valve is not operating
Explanation /Avoidance
Manual override of solenoid valve in thewrong position (manual mode activated)
Troubleshooting Put the manual override on automatic (manualmode deactivated)