Hemingray Glass Company - Muncie, Indiana

The Story of Hemingray Screw Glass Insulators

[Trade Journal]

Publication: Telephony

Chicago, IL, United States
vol. 7, no. 5, p. 386, col. 1-2




Among the manufacturers of screw glass insulators in the United States, the Hemingray Glass Company of Covington, Kentucky, stands as a pioneer, whose goods for scores of years have successfully stood the most severe tests, and at the present time are in use in all parts of the United States. When it is taken into consideration that the Hemingray Company was established in 1848 more than half a century ago, beginning the manufacture of glass insulators at that time it can be readily understood why the product of this concern is so well known throughout the country. In the fullest sense have its insulators been "time-tried and fire-tested."




In 1870 the business was incorporated, since which time it has increased its output each year and made marked improvements in the class of goods manufactured. At the present time the claim is made that the Hemingray Glass Company is not alone the largest establishment of its kind in the world, but that its yearly output and sales are more than those of all the other insulator manufacturing industries combined. It manufactures annually many millions of insulators, all of which find a ready market. The factory at Muncie, Indiana, is kept running day and night, but even with the plant working to its outside limit, the company reports that it is behind in its orders. The offices of the concern, at Covington, Kentucky, are a busy hive of industry.




The Hemingray Company manufactures more than thirty different types of high potential insulators, all with "patent drip petticoats." The points or teats on the lower rim of the "petticoat" attract the water on the outer and inner surfaces of the insulator into drops. The drops from these points fall on the cross-arm, thereby preventing the moisture from creeping upon the insulator, and thence to the pin. It is claimed that they have given the best satisfaction of any insulator ever designed for the purpose. The company also makes several varieties of insulating or break knobs, electric light globes and battery jars.




It is the proud claim of the Hemingray Company that to the superiority of its insulators, more than any other agency, is due the marvelous success of high voltage power transmission. The reasons it advances for this cover all the cardinal points in the case. Primarily, perfection of manufactures leads the list, and is given the credit for being the chief feature in winning success in the insulator market. Perfect design, uniformity of quality, and mechanical and electrical strength are also named as leading points of merit in its goods. It has been the one aim and constant study of the Hemingray Company not only to improve its insulators wherever possible, but also to obtain the highest degree of electrical and mechanical perfection in the construction of the same.

One of the leading insulators manufactured by this company is the "Provo" its standard type for voltages of from 10,000 to 50,000. It is furnished in several types. The "Provo" insulators were named after Provo City, Utah, where the main generating station and offices of the Utah Department of The Telluride Power Company are located, and where the insulators were first used.

Another insulator of still greater voltage carrying capacity is the Gerry 55,000-volt type, known also as the 9-inch Muncie type. This insulator is used on the high voltage transmission between Canyon Ferry and Butte, Montana. It is all glass, non-cemented, and it is claimed for it that it has carried as high as 57,000 volts.

A high-tension insulator made by the Hemingray Company recently stood a test of 120,030 volts without a break-down.

Speaking of its insulators in a general way the company in its catalogue says:

Our experience in the manufacture of insulators dates from their earliest use. We have a very extensive equipment for this work, and our factories are advantageously located in the natural gas district. High voltage insulators are given especial attention both as to the quality of glass, and the process and length of annealing. Not the least important is the careful selecting and packing of high voltage insulators. Many times insulators are delivered to the customer which were never fit for use, or arrive in a thoroughly unfit condition. We have been many times complimented on the even grade of our high voltage insulators and the apparent care that was exercised in the packing and shipment.

We will be pleased to furnish on request, full information regarding other manufacturers' statements of measurements on our insulators.

Nearly 100 big electric railway, power and lighting companies throughout the United States use the high potential insulators manufactured by the Hemingray concern, besides scores of smaller companies. The four highest voltage plants on which the "Provo" insulators are used are: The Telluride Power Company, The Logan Power Company, The Power Company and The Kalamazoo Valley Electric Company, all operating at 40,000 volts or over.

Catalogues, price lists and any other information desired will be furnished on application.


Keywords:Hemingray Glass Company : CD 106 : CD 196 : CD 196.2 : CD 190-191 : CD 283 : CD 303-310
Researcher notes:Older articles portrayed the CD 196 looking more like the CD 196.2, but it was probably referring to the former. The other insulators are CD 106 and CD 190/191. The Gerry insulator is CD 303/310. The Provo insulator is CD 283.
Supplemental information: 
Researcher:Bob Stahr
Date completed:July 3, 2009 by: Bob Stahr;