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"The Beginning” by Jim Scott, Sr.

THE GENESIS OF GASKETS: 37° Flared and 24° Flareless
When asked the question, "How did these gaskets get started?", the single word answer is "perception." If you do not establish the target, you stand a good chance of missing it all.

37° Flared Fitting Gasket – Seco 7 AS4824
The "perception" of the need of a gasket began for me with an old 1926 Model "T" Ford I had while in college. In order to make that old 22 horsepower engine work, you had to have a head gasket and gaskets under the spark plugs. Without the head gasket and the sparkplug gaskets you cannot contain the compression needed to fire the fuel-air mixture inside the cylinder. Also without an electrical spark, the compressed fuel-air mixture will not explode. Having changed many spark plugs on Model "T"s, Dodges, Plymouths, Chevy’s, Caddies, tractors, combines, B-24 and B-29 engines, etc., I soon learned that gaskets are essential to zeroing out the interface gap that occurs on all separable fitting assemblies.

Not to understand what compression yield is will produce flawed expectations in separable fittings, not paying attention to compression yield will create "busted knucks" and a pool of escaping fluid media. This phenomenon became acutely raised in a technical problem on the F7U3 Navy fighter built by LTU, Dallas. JP5 jet fuel in closed containers and properly transmitted is O.K., but you let that same JP5 loose in the stringers of an aircraft engine compartment will certainly produce a fire.

The F7U3 had some 1" fuel fittings that transmitted JP5 to the jet engine manifold. At LTV a jet engine caught fire on engine run-up and did a lot of damage. Needless to say, the pilot was no dummy and got out safely. The fire analysis found the genesis of the problem in the 1" flared fittings. "O.K. engineers, now fix it." Since my job at LTV was to "ride herd" on the fittings, tubing and gaskets, I got the problem.

The solution is then, and it is now, to provide a soft malleable material (gasket) at the interface 37° flared cone. Being "perceptive", I took some 25 (soft) aluminum tubing with .035 wall and flared it to the 37°. I made six of them and tried them in the assembly. "Bingo!" It worked like a charm. And it "buttoned up" the system 100 percent. In closing the loop, I established a CPC (company-LTV) standard with written torque and installation procedures. Flying the F7U3 was great, but only fixed one model series of the airplane. This did nothing for the national picture.
In 1958 I moved to California (the largest aerospace city in the world) to promote some of the lightweight fitting assemblies that were delivered for the B-58. (GDA – "Scott Connector Fitting System").

While working for an aerospace manufacturer I called on GDA, San Diego. I contacted the Senior Design Engineer for the Atlas Rocket. The senior design engineer had interest in the lightweight fittings, but his real problem was sealing helium gas. Two Atlas vehicles had been lost because of the loss of helium pressure in the Lox tanks. GDA was using gaseous helium to pressurize the Lox tanks. The senior design engineer said, "Jim, we have a very serious problem with our helium pressurization. We lost two vehicles and will probably lose more. If we don’t fix it, do you have any ideas?" "Bingo!!!", the same problem we had at LTV, except this time it’s helium gas. I told the senior design engineer that "I can fix it." I asked him what line size he was having the most trouble with. He said, "The _" stainless fittings." I advised him that it would take six to eight weeks before I could produce any parts.

Seven weeks later, I called again on the GDA senior design engineer with 50 pieces of the _" (-8) gaskets. We went down to the GDA test lab and inserted them in the helium assembly. We were able to seal helium gas to a 10 to the minus 8 measured in a mass spectrometer. That pencils out to a one molecule a year leakage rate. You can’t get any better than that. "Bingo!"
This effort proliferated our standard into 22 line sizes in four materials (aluminum, copper, nickel and stainless) Seco is tooled to make all of them. Seco keeps the 88 line sizes on the shelf for a two-day turn-around for shipping.

 

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