3 replies to this topic

[J_Leo]

Dear,

 

For relief valves, we usually set one spare. For rupture disk, there is only one on line at a time, what is the spare practice? Maybe store a couple of them in warehouse?

 

Thank you!

Leo

[ankur2061]

Leo,

 

Isn't it obvious why there is no installed spare for a Rupture Disk?

 

For a relief valve any problem such as chattering or internal passing of the relief valve, you can switch to the installed spare without normally stopping the process and continue with the installed spare till the repaired relief valve is installed back.

 

For a rupture disk also called as a burst disk mounted on any equipment operating under pressure, once it bursts, in most cases you need to stop the process and isolate the equipment for replacing the RD. If you have to stop the process and isolate the equipment then there is no justification of having an installed spare.

 

There may be very rare instances where you don't need to stop the process and isolate the equipment once a RD has burst and an installed spare can be quickly put on line without any hazardous consequences. But having an installed spare for a RD would be an exception rather than the rule.

 

Hope this explanation helps.

 

Regards,

Ankur.

[Lowflo]

First, verify whether the disk is really necessary. The owner is better off using a reclosing device (PSV) unless there's a specific reason why a disk is necessary.

 

It's far cheaper to buy spare disks with the initial order. Disk manufacturers make their money from replacements.The number of spares needed will depend on the risk of premature failure. If it's a liquid filled service, a cycling vapor service, or any service that operates within about 25% of burst pressure, then the owner will need plenty of spares. Better yet, don't a disk in the first place if you have such a system.

 

For those application where a disk is essential, I generally spec 3 spare disks.

[fallah]

Leo,

Although it is usual that several spare disks being kept for operational requirement, it isn't strange that two bursting disks being used in parallel with a three way valve to allow a switch to the second disk upon first disk failure...