1986 >> May >> The CD 211 Brookfield Noleak D  

The CD-211 Brookfield Noleak D
by Elton Gish

Reprinted from "Crown Jewels of the Wire", May 1986, page 32

You must be asking, 'What is a mud collector doing writing about glass". Well, this mud collector started out collecting Brookfields and I still have a soft spot for something to sit in a window and look pretty, not that Brookfields are all that colorful. But, I do have a niche among all the mud that is reserved for glass.

Last summer I visited several collectors in the Seattle area and could not resist getting a Brookfield NOLEAK D with glass insert from Winslow Trueblood. He had painstakingly dug several of these along an old line in the mountains east of Seattle. 

The glass inserts were rarely found undamaged and I felt fortunate to get one in good condition. Then, on one of the many trips I made last year to several Texas universities to research old trade journals for articles on mud, I accidentally found an article on the NOLEAK D.

The article was in an issue of the "Journal of Electricity, Power and Gas" dated February 10, 1912, page 12. I searched every issue prior to that article trying to find the reference, "About two years ago the Journal made mention of this new insulator...'.. The only reference that I could find was a patent summary in the issue dated April 11, 1908.

The test results, if they can be believed, are quite convincing. Note in the last paragraph that the article refers to two forms of the Noleak insulator. Of course, sketches of insulators in these early articles are seldom accurate, so we may never know what the first units actually looked like.

Following the article is a copy of the March 24, 1908 patent #882,803.

The Pacific Coast Highway will probably be congested with collectors looking for the Noleak insulator described in those tests and don't expect to find many available boats to Goat Island either. Happy hunting.

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From the first days of the telegraph, more than sixty years ago, it has been the aim of the transmission companies to find an insulator that would remain an insulator in good weather and in had. Up to the present time it has been the expectation that during a drizzle or a fog, the wire facilities would be materially lessened owing to leakage and the cross-fire that takes place on every crossarm.



Type of Insulator Used in Test.

Now comes the "Noleak" insulator, in which the under part, that is the petticoats, and the space between the petticoats, is protected from dust and moisture. A dry clean space is always present between the conductor and the pin. This effectively stops the leak age that must always obtain with the ordinary insulator when it becomes dirty.


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About two years ago the Journal made mention of this new insulator, and in view of the importance of improved insulation it now takes pleasure in giving the results of a test of twenty-eight months on 71 miles of line through a fog belt along the coast of Southern California. 

After five months use the following report was made:

"The difference in the actual working of the two wires was very noticeable. No. 2 was very heavy and San Diego had difficulty in adjusting, while No. 4 (equipped with "Noleak" insulators) was clear and could have been worked at high speed."

After seventeen months' use the conditions were stated thus:

"Since the Installation of the "Noleak" insulators there has been a great improvement in the working of the two wires. The cross-leak has been reduced to a point where it does not trouble us, and the two wires have been simultaneously workable. Normally the wire insulated with the "Noleak" Insulator shows from one-fifth to one-half the escape of the other wire. The elimination of the cross-leak, however, is the best achievement of these insulators, and I believe it is only fair to give them full credit. as the cross-leak has certainly been eliminated since the "Noleak" insulators were put on."

After twenty-eight months' service this statement was given:

"The conditions are practically the same as when I wrote you a year ago."

The chief object sought for by the designer of this insulator, L. W. Storror, who has been prominently identified with the telegraph and telephone service on the Pacific Coast for many years, was to overcome the leakage and cross-fire which threw the greater portion of the lines in the fog belts out of commission every time there was a fog or a drizzle. How successfully this object has been accomplished is shown by the foregoing records.

A more recent series of tests, extending over a period of six months, has just been made. In July, 1911, one pair of aerial wires across Goat Island was equipped with new standard D.P. Insulators, and another pair of wires was equipped with Noleak Insulators. Tests have been made twice a day on seventy-nine days since October 20th, 1911. The lowest measurements of each wire, taken at the same time, indicate that the Noleak Insulator has one hundred and eighty-four per cent greater efficiency than the standard D.P. Insulator. 

With this will be found a sketch of the latest pattern of the Noleak Insulator. Eight and one-half inches of insulating surface intervenes between the line wire and the pin, and it is claimed that one-half of this distance will always remain clean and dry.

Insulation experts have declared that sixteen percent increased distance between line and pin means 100 percent greater efficiency. The new form of insulator has 25 per cent more insulating distance than the form upon which the tests were made.


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