People - Elmer G. Fridrich

Biography
Elmer G. Fridrich was born on April 11, 1920⁵. He started out on the path to become a chemical engineer, however in his second year he decided that perhaps that wasn't the right career route for him. Instead, he took courses in explosives and found employment as an inspector of powder and explosives. As this was during the outbreak of World War II and the draft was in effect, Elmer entered into Ordnance at the Aberdeen Proving Ground in Maryland. His attention was directed toward neutralizing unexploded German bombs. Elmer attended a specialized Army training program at Pennsylvania State College. This led to service in the Chemical Warfare Service at Camp Sibert, Alabama. Towards the end of World War II Elmer taught machine shop skills as a therapy aid at Welch Convalescent Hospital.

Elmer Fridrich started his General Electric employment at the Cleveland Welds Works as a machinist. His talent in developing the necessary apparatus was soon recognized, and it was recommended that he be transferred to the Nela Park headquarters. At Nela Park Elmer worked under Duryea E. "Red" Elmendorf, to develop a less expensive inside coating for incandescent lamps as well as a zinc oxide light-diffusing coating.

After a period of time Elmer was assigned to work under Alton Foote, the team leader of the group that was to develop a quartz heat lamp.

The Invention of the Halogen Lamp
The use of halogens in lamps was trialled as early as 1882 by Edwin A Scribner of the United States Electric Lighting Company, who patented a chlorine-filled lamp which was not successful. The idea was picked up again in 1892 by John Waring of the Waring Electric Company, who patented his Novak Lamp as a circumvention of the Edison patents. As the name implies this lamp contains no vacuum, but has a smal pressure of bromine inside the bulb. This was also not successful - probably the bromine had very little effect. Although it was declared that Waring's lamp was still in violation of the Edison patents, he escaped closure as the Edison patent itself expired in 1894 - after which his company reverted to vacuum lamps.

The next noteworthy attempt to use a halogen occurred in the early 1950s following the formation of a small group, for the purpose of developing a heat lamp, at the General Electric lighting headquarters of Nela Park, in E. Cleveland, Ohio. The group was under the leadership of Alton Foote. The lamp, which was to be used for drying purposes, was to have a small diameter outer envelope of fused quartz instead of the traditional larger reflector type bulb. A marked difference between the reflector type of bulb and the quartz bulb is that the quartz can withstand much higher temperatures. During operation it is possible for the quartz to become red hot.

Linear quartz heat lamps were made in the laboratory but sometimes it was found that they would blacken. One of the workers in the group was Elmer G. Fridrich. His assignment to that group resulted in an unforseen benefit to the lighting industry that was to be realized many months later. Elmer had read about a refining process for exotic metals in a chemistry and metallurgy magazine; the process utilized a halogen cycle. For about six months the similarity of the refining apparatus and a vertically burning quartz heat lamp continued to intrigue Elmer. One day, after the chores of the workday had been completed (that is, following the making of a certain number of heat lamps), Elmer asked Al Foote if he could pursue an idea that he had; the idea was to put some iodine in the lamp to determine its effect. Permission was granted, and Elmer then consulted with some of the older technical personnel, including Carl Kenty. It was during these consultations that Elmer learned that halogens had been tried in (carbon filament) lamps before. At least two patents had been granted, as mentioned above. As a result of these consultations it was decided to proceed with the idea to add iodine to some lamps.

One of the engineers at that time was William F. Hodge. Bill was nearing retirement and in his laboratory he had an unused vacuum system that was offered to Elmer for lamp processing. In addition to allowing Elmer to use his vacuum system, Bill supplied Elmer with tubulated clear quartz heat lamps which had tungsten supports. Another colleague, Mary Jaffe, supplied Elmer with iodine. At that time Elmer had no experience in "tipping off" lamps and so he approached another colleague and friend, Emmett H. Wiley, who did have the necessary experience in tipping off lamps from a vacuum system. The stage was now set for the first quartz tungsten filament halogen lamp to be made with a measured amount of iodine. Unlike many initial attempts at invention, this one was to be, in Elmer's own words, "A howling success." The promise of a workable lamp seemed assured. It was to be found out later, however, that short lamp life was experienced. It became clear that additional investigations were required in order to result in a product that was consistent in its performance.

One of the key members in the engineering group who helped establish the necessary lamp design and manufacturing equipment for the dependable operation of the iodine cycle was Fred Mosby.

It was found during the investigation of blackening that impurities in the tungsten wire played a role. In the case of iodine lamps Mosby said¹:

"Because oxygen, as part of the iodine cycle, is required for it to operate, it is essential that a quantity of oxygen is available throughout life of the lamp. Tungsten impurities, if not controlled, form stable oxygen compounds that deplete oxygen thus causing the lamp to blacken. It is very difficult to control oxygen and impurities in the iodine cycle lamp."

When the darkening of the new quartz heat lamps was recognized as a real problem it was decided in early 1954 to bring Ed Zubler, a physical chemist, into the picture. Zubler and Mosby helped to determine satisfactory iodine and oxygen levels as well as the tolerable wire impurity levels. Developments such as these are often result of combined efforts of several individuals. Unlike the more usual effort of one individual in days past, synergism is the key to success today. A great advantage of developing a product by a group of people is that a wide range of talent, education and experience comes into play. As time went on Fridrich and Wiley played reduced roles in the project.

Fridrich and Wiley applied for a patent on their basic idea of the halogen lamp on 3 March 1958, and U.S. Patent 2,883,571 was granted on 21 April 1959. In that patent a modified lamp design also was presented by Fridrich.

The Gemini Halogen Lamp
Later in time Fridrich proposed another halogen lamp which he called "the Gemini", on account of its twin miniature halogen capsules within the same outer envelope. One of the early problems of creating a halogen lamp to replace the ordinary general service incandescent bulbs is that it becomes increasingly difficult to create lower wattage high voltage halogen lamps, due to problems of supporting the relatively long and thin filament, and keeping the end seals sufficiently hot for correct operation of the halogen cycle. In addition the high operating pressure of the halogen capsules presents an increased risk of explosion at end of life. In the Gemini lamp these problems were partially overcome by developing a miniature halogen capsule having a specially shaped burner, and designed to operate at just 60V, thereby halving the filament length and also reducing the internal gas pressures. Two such lamps were operated in series within a single outer bulb. An experimental mock-up created by Fridrich in 1974 can be seen in the lamp collection of the National Museum of American History, and is pictured below. However various other problems, not to mention its high cost, prevented this lamp from being marketed.