A History of Valves

The Great Teflon War

13 wnt teflon 1The late 1950s saw the introduction of Teflon as a valve material for seals and closure members. This vintage Dupont ad touts the exemplary properties of Teflon as a membrane material for diaphragm valves.You might call it either the “Great Teflon War” or “The Battle of Massachusetts,” but either way, the fight took place in the courtrooms of The Bay State, rather than in its cities or countryside. No matter how it’s labeled, however, the victory prize was substantial: rights to the patent for the first functional bidirectional elastomer-seated ball valve.


The saga began in the laboratories of the DuPont Chemical Company in the years preceding World War II. Chemist Roy Plunkett was searching for a new form of refrigerant when he stumbled upon polytetrafluoroethylene (PTFE) resin quite by accident. After creating his “mistake,” however, he began to analyze the sample and discovered that the properties of the new compound were unmatched by any other material. At this point DuPont knew it had a winner, and so it coined and registered the trade name “Teflon” to identify the new substance.

The new material was immediately put to work in a secret endeavor in which DuPont assisted the government—The Manhattan Project. Teflon was used for gaskets and seals to contain the corrosive uranium hexafluorides and other tough applications required for the atomic bomb project.

At about the same time (1942-1943), the Navy was having trouble fighting shipboard fires and needed a better spray nozzle, one that could create a blanketing fog to smother a fire. A young engineer for the Rockwood Sprinkler Company, Howard G. Freeman, solved the problem and created a fog nozzle. The Navy was impressed and called upon Rockwood and Freeman for other solutions. During this period, Rockwood also became involved with the Manhattan Project. As an insider, Freeman learned all about the new DuPont Teflon material and the miracles it could accomplish.


13 wnt teflon 2The idea of a ball or spherical valve is not new, as this 1871 patent granted to John Warren clearly shows. Unfortunately the bronze to bronze, non-energized seat design did not work too well or last too long. It would take 80 years for the proper seat materials to become available, which would make the ball valve the workhorse that it is today.The principle of the basic ball valve or spherical plug valve as it was also called, goes back to the 19th century, with the first patent issued for a metal-seated ball-type valve (patent #0117704) in 1871 to John Warren, who assigned it to John Chapman, the founder of Chapman Valves. The design was generic and does not appear to have been put into production. Additional ball valve designs ensued over the next 60-70 years but the effective soft-seated ones were only unidirectional in function. The problem of the day was how to create a bidirectional soft-seated ball valve.

Howard Freeman, although well compensated at Rockwood, yearned to start his own company and create the first bidirectional, zero-leakage ball valve. Freeman left Rockwood Jan. 25, 1955. His new company, called Jamesbury, began business the next month as Freeman put his ideas for bidirectional seats on paper and began making the valves. The key to the valve’s success and the heart of the patent was the design of the flexible Teflon seats, which created a positive seal in either direction. Freeman filed for a patent on the design in February of 1958 and patent #2945666 (a.k.a. the “666” patent) was granted in July of 1960.

13 wnt teflon 3This is the famous Freeman “666” patent that kick-started an industry and created a lot of income for the legal community along the way.The success of the valve was tremendous, and not surprisingly the lawsuits began to follow. The first court battle was waged between the new owners of Rockwood (E. W. Bliss Co.) and Jamesbury. The suit, which was filed in 1966, claimed that the idea for the “666” patent valve was conceived while Freeman was still with Rockwood. Bliss claimed that “an undisclosed idea is an invention” while Jamesbury countered “that an idea must be written down or documented before it becomes an invention.” The federal Appeals Court ruled in favor of Jamesbury in 1971.


The U.S. Navy was an early proponent of the Jamesbury valve for use in its submarines. It was quiet, easy to open and close, and leak tight. Unfortunately, shortly after Jamesbury’s initial sales to the government for the U.S. nuclear navy, the Navy allowed other suppliers, including prime contractor, Electric Boat, to infringe on its patent. Electric Boat began building Jamesbury-designed valves without permission thinking that “little” Jamesbury wouldn’t fight the Navy’s favorite son, Electric Boat. They were wrong.

Jamesbury filed suit against the government as well as all the vendors that manufactured Jamesbury-patented designs. It wasn’t until 1980 that the suit against the government was successfully won by Jamesbury, and other suits against vendors in this case were not settled until as late as 1988.

An interesting anecdote to the Teflon ball valve story surrounds the patent by Crane Valve Company for a soft-seated ball valve design (also called a spherical plug valve), patent number 2373628, which was granted in 1945. The Crane design used spring-loaded, graphite-impregnated rubber seats for bidirectional sealing. It is not known how well the valve actually worked because during those booming post-war years, Crane decided to concentrate on other valve types. According to a retired Crane engineering manager, at that time “the com­pany could see no useful purpose in that type of valve design and that future sales success could not be guaranteed.” Obviously, timing is everything, including in the valve business. Perhaps if Crane, while it was assisting with the Manhattan Project and nuclear navy projects, had learned of and applied the technology of Teflon to their ball valve seats, history would be different.


13 wnt teflon 4An elastomer-seated ball valve is fitted with energized Teflon seats that allow for bidirectional sealing.The last 25 years have seen an explosion of bidirectional soft-seated ball valve designs from all over the world. The technology and designs are now mature, and the valves are used everywhere. The original Teflon material has been updated and upgraded with additives such as glass fibers and carbon put into the mix to increase mechanical properties and temperature resistance. Meanwhile, the dust has settled on the courthouse floors of Massachusetts and the Great Teflon War has been won, at least for the valve industry. Teflon is now used in many types of valves as well as cavity linings and seating inserts.

And of course, the entire nation now knows about the wonders of Teflon, though most of us think about non-stick cookware. No doubt chemist Roy Plunkett would be both surprised and pleased at what his invention has wrought.

GREG JOHNSON is president of United Valve (www.unitedvalve.com), Houston, and is a contributing editor to VALVE Magazine. He serves as chairman of VMA’s Education & Training Committee, is a member of the VMA Communications Committee and is president of the Manufacturers Standardization Society. Reach him at This email address is being protected from spambots. You need JavaScript enabled to view it..