I wrote an article on this subject for "Valve Magazine". It was called "The Great Teflon War". The magazine is available for free download at www.valvemagazine.com.
It sounds like it was an out of tolerance part. Had the valve been repaired before? Sometimes a valve repair facility will machine the seat pocket during the repair process and then install a custom ring to fit the new slightly deeper pocket. That creates a problem in that OEM seats will now no...
That is correct. "Level 3" is kind of used as a defacto acceptance standard by many organizations. The problem is that it is a grade or level that exceeds the general casting quality of most of today's imported commodity cast steel valves. On the API RP591 "User Acceptance of Refinery Valves"...
The original valve design standard will stipulate which test must be performed at time of manufacture. In order for the valve to meet its design standard (API 600, ISO 10434, API 603, etc..) EVERY valve must be tested at the factory at the time of final assembly. The most common test standards...
Your customer is not quite correct. Those tables list various categories of defects along with the acceptable defect levels that must be met in order for the valve to meet "special class" in accordance with ASME/ANSI B16.34. Since at this time there is no other standard to reference for casting...
I wrote an article for Valve Magazine on gate valves about a year ago. The text is on our website at www.unitedvalve.com. Just go to the articles link and it will be there.
The best place to start is to obtain a copy of the book "The Design of Valves and Fittings" by G. H. Pearson. It was published about 50 years ago, but it is still on the shelf of nearly every valve designer. It is out of print, but can usually be found at www.abebooks.com or www.bookfinder.com...
I reviewed most of the published valve books for an article I wrote a couple of years ago. The best "handbook" on valves is "The Valve Primer" by Brent Stojkov. It is cheap, concise and easy to read. It should be avialable on Amazon.com. My company has given away over a hundred copies to customers.
API 598 is a stand-alone document and has no relationship with ANSI/ASME B31.1 or B31.3 construction codes. API 598 is referenced as the testing standard for valves made to API downstream valve standards such as API 600 (gate valves) and others. The only ANSI/ASME standard that comes close to...
The predominant standard for ball valve leakage is API 598. My company tests thousands of ball valves each year and other standards are rarely referenced. About once every 2-3 years someone (probably a control valve engineer) will request testing per ANSI/FCI 70.2 on ball valves.
I was a member...
Ball Valve History-
I just came across the thread on ball valve history. I am writing a book on the history of steel valves in the US and as part of my research, I have spent many hours at the US patent office. Here is the "readers digest" version as I have researched it.
The first spherical...
Tod,
The current Edwards catalog says that valve has a "40 year or 40,000 cycle, zero leakage guarantee when used in nuclear service". What does your local Edwards rep say?
Regards,
Greg Johnson