9 replies to this topic

[Art Montemayor]

S Le:

I suggest you go to the Rupture Pin Technology webpage:

http://www.rupturepin.com/

and read their presentation there. These people in Oklahoma have told me that they have licensed the technology to ProtectoSeal, Inc. of Illinois, who is marketing and applying the buckling pins to industry.) ASME recognizes the certification and application of rupture pins/buckling pins and I am sure that the folks at either Rupture Pin Technology or ProtectoSeal can tell you exactly what paragraphs or section within the ASME code you can find the verbiage that states their recognition. They will also answer your specific questions.

I have used Buckling Pins since 1989 and recommend them to anyone who is employing rupture discs. In my opinion, with the technology and historical track record set by the Buckling Pin, there simply is no manner that the rupture disc can compete with the Buckling Pin with regards to:

• Engineering accuracy;
• Repeatability results;
• Corrosion immunity;
• Dependability and reliability;
• Flexibility;
• Capital cost; and,
• Spare parts cost.

I am an old time user of rupture disc and even worked for Black, Sivalls & Bryson (BS& – the people who wrote the book on the rupture disc – but I cannot see any justification in their process application today in light of the many engineering advantages offered by buckling pins. I hate to admit it, but in my opinion the rupture disc is now obsolete. Even BS&B has admitted as much in developing their own buckling pins. The era of the rupture disc is essentially over. The King is dead; long live the King!

Art Montemayor
Spring, TX

[pleckner]

In Part 6 of my series on rupture disks, I list two references for the Rupture Pin, one of which is repeated by Art in his reply. I invite you, as did Art, to go to these sites and learn all you can. They are indeed great devices.

As far as your questions go:

1. The acceptance of Rupture Pins for use as primary relief devices is not specifically stated in ASME Section VIII, Div 1, paragrpah UG-127 as you point out. However, it was accepted by the ASME Committee in a reply to an inquiry and is now part of Code in the form of CODE CASE 2091 and CODE CASE 2169.

2. I'm not a mechanical expert but the housing for these devices fall under the same criteria as do relief valves and these are not hydrotested after installation. You would have to ask the specific manufacturer for any details.

3. Yes, the rupture pin is classified as a spring loaded, non-reclosing relief valve.

[pleckner]

You'll have to ask the manufacturer but I can safely say this. All valves are designed to a maximum mechanical pressure and temperature, similar to vessels. These values are published in the catalogs for that manufacturer.

I'm curious as to why you are so concerned about this. If you buy an ASME coded valve, there is nothing to worry about.

Again, ask the manufacturer for any specific questions related to the mechanical design/operation for their valves. They will be more than happy to discuss this with you.

[Art Montemayor]

Holy Mole! and Suffering Soccatach!

Thanks to Phil for asking the correct and probing question. Now, finally, we find out "the rest of the story"!

To all who write in asking for help and advice:

Please, Please give us ALL the basic data that you have available! Why do some engineers act like "secret squirrels" and retain important and basic data? Are they afraid we are going to abscond with it? Are they going to be the poorer for it? Do they believe that the answer or reply they receive will be flawed if they give us all the correct and truthful data? What happens is just the contrary. The quality of the response is directly proportional to the quality (& quantity) of the basic data supplied. With poor and deficient basic data we can only reply in a general and speculative manner. The reply could be mis-interpreted or mis-applied.

If we had been told at the very onset that this application deals with 15,000 psig Hydrogen, we could have saved a lot of time and effort in getting down to the essential problem. This is a very unique and special application - not only because of the pressure level, but also because it deals with a very minute and small atom. It is very difficult to maintain a positive and bubble-tight containment around one of the Cosmo's smallest molecules! In this particular application, I dare to say that perhaps both Phil Leckner and I might get in a huddle and think this over, ultimately coming out with the proposal that a rupture disk might be the better option over the buckling pin. But we still need ALL the rest of the basic data.

To all our friends and colleagues out there: Please heed the direction this query started out on and where it ultimately led to. In the future, please submit ALL your basic data and an accurate description of your application if you expect an experienced and accurate response. I know that Phil Leckner, like myself, takes his responses to queries very seriously and always considers the responsibilities this infers. Readers of our responses can generalize and apply a response in a wrong and hazardous situation if they don't have access to all the facts and basic data.

We want to help each other on this forum and furnish good, prompt, and positive help and experience to all who sincerely and honestly need it. But we need to be concerned about furnishing only piece-meal, deficient, and poor basic data - and yet expect a concise and accurate response. The last and least thing we ever want to do is furnish a response or suggestion and later find that it was mis-applied or resulted in someone getting hurt. That is not engineering; that is stupidity being practiced - something engineers should not be involved in. I hope I haven't hurt anyone's feelings by writing in this frank manner, but I feel a responsibility for what I respond on and I know that the key people that form this Forum - like Phil and Chris Haslego - also share that concern and resposibility of furnishing correct, accurate, and safe advice.

I am very interested in anyone's opinions and points of view on this subject because I continue to see examples of sparse and deficient basic data elsewhere.

Art Montemayor
Spring, TX

[pleckner]

To all, please, please and please read carefully what Art has written. It cannot be emphasized enough!!

And one additional thing. The manufacturer is not responsible for sizing (determing load and conditions) any relief device but he/she is an excellent source for information and advice on the design and application of their particular devices. Do not hesitate for one second in seeking them out. And their consult is free too!