Tag Archives: Crane

Metal Bellows Seals

Several requests had been made for engineering guidelines regarding metal bellows seals.  Although I like metal bellows seals, I don’t consider myself expert in their design.

SealFAQs does include some comments and anecdotes about metal bellows seals including the history and development of stationary metal bellows seals but no real details about design or application.

Fortunately, John Crane has recently published “Seven Things to Know …” about metal bellows seals in their blog. 

Blogs about Mechanical Seals

A blog is a “weblog”, that is, an online journal or informational website.  Posts to a blog appear in reverse chronological order. A blog can be about anything. Many blogs are personal in nature and often are similar to a diary.  The first blogs began to show up about 1994 and were primarily text with a single author.  A blog is expected to be updated more frequently than a website and also to be somewhat less formal.  Blogs usually have a byline or author and the blog site includes the ability to find previous posts by author, date, category and tags.

A blogger is simply someone who operates a blog or blog site as opposed to someone who authors a post for a blog or website.

Blogs can generate money through sponsors and links to commercial sites; however, SealFAQs does not do this.

One problem with hosting a blog is the commitment to maintain it and to add new posts regularly.  Having neglected my own blog for several months, I’m well aware of this problem.  After a while, the newness and uniqueness of the blog sort of wears off and the blogger runs out of things to write about.  Fortunately, I have plans and topics for 2020.

Manufacturers Blogs

There are several different types of blogs.  Some seal OEMs operate a corporate blog to provide information and updates about their products.  Here are some links to OEM “blogs” that are specifically labelled blogs.

John Crane has a blog, https://resources.johncrane.com/blog/, attached to its main website, JohnCrane.com.  The Crane blog addresses a variety of subjects and appears to be somewhat irregularly updated.  The Crane blog appears to be a mix of technical articles, product announcements, news and field experience.  The author(s) name is not given.  The Crane blog began December 13, 2018.

Chesterton has a blog, https://blog.chesterton.com/, attached to its main website, Chesterton.com.  The current topic is part 4 of a series on double seals and barrier fluids; it dates to October 31, 2019.  Although good information, the overall feel is not that of a “blog”.  Apparently several authors contribute.  The Chesterton blog dates back to at least 2017.

Sepco has a blog, “Seal Connect”, at https://www.sepco.com/community/blog/, with posts by various authors dating back to July 23, 2019.

Flowserve does not appear to have a blog, as such. 

EagleBurgmann does not appear to have a blog, as such. 

Non-Manufacturers Blogs

SealFAQs is not a manufacturer sponsored blog.  There are a few other such blogs, but not many.

The Fluid Sealing Association (FSA), the International Trade Association for mechanical seals, has a blog, http://www.fluidsealing.com/mechanical-seals/mechanical-seals-blog/.  The FSA blog doesn’t feel like a conventional blog.  Posts tend to come from the various member companies of the FSA.  Many of the FSA posts were published in Pumps and Systems Magazine as part of the “Sealing Sense” series.  The most recent post was published in June 2019.

There is a relatively new blog at https://www.mechanicalseals.net/Mechanical-Seal-Blog/index.php?frontpage, with the title “Mechanical Seal Tips and Details”.  It has only three posts and has the feel of a project that was undertaken and then stopped.  However, it was off to a good start.

Seal Websites

Of course, there are other websites containing information about mechanical seals and a few use the word “blog” in their description but don’t really have the feel of a blog.

Wikipedia has a page for mechanical seals, https://en.wikipedia.org/wiki/End-face_mechanical_seal as well as a page for the seal standard, API 682, https://en.wikipedia.org/wiki/API_Standard_682.

If you are aware of other mechanical seals blogs and especially if you have a favorite mechanical seals blog, please leave a comment.

The Development of the Stationary Metal Bellows Seal

Figure 1. Early concept (ca 1976) of stationary metal bellows seal for low temperature.

Stationary metal bellows seals as we know them today were developed as part of a seal reliability program at Exxon’s Baton Rouge refinery in the 1970s.  The Exxon “Pump Team” was not satisfied with reliability and performance of seals in hot oil services because the oils decomposed and locked rotating flexible sealing elements in place.  Beginning in January 1976, prototype stationary metal bellows seals were designed, manufactured and assembled by the Exxon Pump Team using parts from various seal manufacturers fitted into custom assemblies manufactured in the Exxon machine ship.

The Exxon Pump Team tested 19 prototypes in many variations before deciding to turn over the designs and results to the seal manufacturers.  There was some consideration for seeking a patent but it was thought that commercial development of the concept would be better done by the seal OEMs.

I know this for a certainty because I was there and took an active part in this project.

The story of the stationary metal bellows seal is told in more detail on this page of SealFAQs.