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.
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.
Yesterday I attended a crawfish boil sponsored by John Crane Inc. – my previous employer for some 28 years. It was great to visit with my former coworkers and fellow retirees. In addition to the local folks, a few John Crane engineers and salesmen came from Houston to enjoy some crawfish. There were even some executives from Morton Grove (Chicago) who joined in the fun. All total, I’d guess that there were some 400 people at the crawfish boil.
I met and enjoyed talking to the new president of John Crane, Jean Vernet. He narrates an interesting video about John Crane and seems interested in the history and culture of the seals industry. I have my fingers crossed that he will be a good leader for John Crane Inc.
Yesterday’s party reminded me of the first crawfish boil I attended. In the early ‘70s, I was a young engineer who had moved to Baton Rouge from East Texas to work at the Exxon Refinery. Although raised on the Mississippi Coast, I knew little about crawfish. In those days, Chempro (became Sealol, now part of John Crane Inc.) was an up and coming supplier of high temperature edge welded metal bellows seals – especially at Exxon. Chempro decided to have a small crawfish boil in the parking lot in front of their little office. During the course of the afternoon, there may have been 50 people in and out of the party. It was a great success.
Chempro/Sealol continued to have an annual crawfish boil for many years with each event becoming larger than the previous one. Soon the crawfish boils were getting out of hand with well over a thousand people – invited or not) attending. (OK, so after becoming part of John Crane, John Crane executive management ended the crawfish boils in 2000.)
Crawfish are cooked by dumping live crawfish into boiling water having spicy seasonings. (You learn not to eat the crawfish that are not curled up; these were dead before being dumped into the boiling water.) Usually potatoes and corn on the cob are cooked along with the crawfish in the boiling water and spices. The mix of spices range from modified commercial packages (“But I also add ….”) to the family secret recipe.
The thing about eating crawfish is that it takes (or seems to take) more energy to peel one than is gained by eating it. The edible part (for me anyway) is a small morsel in the tail of the crawfish which must be separated from the body by removing the shell. Especially for me, peeling the crawfish is a slow and tedious process. So you don’t get full by eating crawfish. You might get full by eating corn or potatoes or drinking beer but not by eating crawfish. (The John Crane crawfish boil also included white beans and jambalaya.)
And then there’s the waste. A crawfish boil might allow for two or even three pounds of crawfish for each person (depending, of course, on the invitees). However, only that small morsel is eaten. The head, claws and shell are discarded. By volume, it appears that nothing has been eaten. Trash collection, disposal (the smell is horrible after a couple of days) and lots of paper towels are a necessity at a crawfish boil – not to mention beer.
The John Crane 2018 crawfish boil was a tremendous success as far as I am concerned. I’m already looking forward for the 2019 version.