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Rupture Disc Major Problems |
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Rupture/Buckling Pin Solutions |
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Discs fatigue and usually fail early.
Yearly replacement is recommended. |
Buckling Pins cannot fatigue;
They buckle at set point. No yearly replacement required. |
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With the many manufacturing
tolerances, working close to set point
is impossible. |
Maximum operating pressure to
95% of set point. Zero leakage to
set point. |
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Downstream fragmentation. Metal
and plastic chards clog and damage downstream equipment. |
No downstream trash possible. |
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Vacuum support may be required. |
No vacuum support required. |
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Many manufacturing tolerances (manufacturing, temperature and set point). Pressures below 40 PSI have severe accuracy penalties. |
Tolerance below 5 PSI, +/– 9%.
5 PSI and above +/– 5%.
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Senses differential pressure only.
A major problem with containment
systems. |
Can sense upstream pressure only
or differential pressure only. |
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Discs can be installed improperly. |
It is difficult to imagine a pin
installed improperly.
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Discs are in contact with corrosive
system fluids. |
Pins are external to the process
fluid and are made of corrosion
resistant metals. |
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Costly storage and handling
required. |
Pins are rugged and can be stored
at the valve. |
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Costly time is required to change the discs.
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Pin changing is done with one man
in minutes, even with large valves. |
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It is difficult or impossible to tell when a disc is damaged or has burst. Open line visual inspection is usually required since broken
disc indicators are not reliable. |
The Buckling Pin has two conditions – straight or buckled – making it visually apparent. A
proximity switch may be added to sense a rising valve stem and is very reliable. |
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To change settings, you must
break the line, which could cause pollution. |
Settings can be changed in minutes without breaking the line using the "Poco" system option. |
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Since the temperature of the disc
is not monitored, you do not know
the set point. |
The pin is not system or ambient
temperature sensitive. |
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Burst stress is much greater than
yield stress. |
Buckling stress is much lower than yield stress. |
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In many cases, vessels are over- designed to allow for rupture disc inaccuracies. |
Rupture Pins are accurate, no vessel over-design is required. |
