The ubiquitous gate valve has a long history of serving the flow control industry in the United States. From its humble beginnings during the middle of the 19th century, to its universal usage today, the gate valve has soldiered on behind the scenes of America’s industrial pageantry.
The first valve patent in America was for a gate valve. It was issued in 1839 to New Haven resident, Charley W. Peckham. Although Mr. Peckham’ s patent was for a sluice gate valve, it was a gate valve nonetheless. It wasn’t until 1840 that the first gate valve as we would recognize it today was patented. It was called a “stop cock” and was issued to Theodore Scowden of Cincinnati, Ohio. Mr. Scowden’s valve was actually a unidirectional gate valve with a primitive bolted bonnet.
The control of steam was the driving force behind virtually every new valve design to come to life from the draughtsman’s table during the period from 1850 through the turn of the 19th Century. This embryonic period for the American valve industry saw many future flow control manufacturing icons get their start: William Teller Crane (Crane); Edmund H. Lunken (Lunkenheimer); William Powell (Powell); H. G. Ludlow (Ludlow); Rufus B. Chapman (Chapman); Charles Jenkins (Jenkins); Daniel Kennedy (Kennedy); and Rufus Pratt (Pratt & Cady). All of these men patented their valve designs and founded companies that would later become well known in the field of flow control.
Other inventors were also striving to improve gate valve design, primarily in the area of disc and seat construction. In 1896, William Jennings, an engineer for the Pratt & Cady Company, patented the screwed-in seat ring design that would remain the standard for the next 75 years, until advancements in welding technology rendered the screwed-in arrangement obsolete.
As the steam power industry matured and boiler temperatures and pressures increased, the valves had to keep up. In some case boiler manufacturers couldn’t get the valves they needed, so they designed and manufactured their own.
Not until the first decades of the 20th century did steam pressures begin to move past the 150-200 psi level. Until then, these low pressure applications were easily handled by the brass and iron valves of the day. Cast iron valves could also easily handle the modest 350-400 degree temperatures in these days prior to high temperature superheaters and steam turbines.
Innovations in the power industry resulted in the rise of operating temperatures and pressures around the 1915-1925 period. This situation fostered the rapid development of a new valve material- steel. Steel could take the pressures and the temperatures that piping in the new central power stations required. During this period of maturation, the steel gate valve adopted the design and appearance that it is still known for today. As operating temperatures and pressures continued to rise, new chrome/moly alloys began to be employed in valve construction.
Powerful new compounds developed by the chemical and petro-chemical industries created corrosion challenges for the valve manufacturers. These challenges were met by a host of new alloys such as Hastelloy, Alloy 20 and Inconel.
The last big advance in gate valve design occurred during the early 1940’s with the invention of the pressure-seal bonnet. The pressure design reduced the mass and weight of large high pressure gate valves by as much as 40%. Pressure seal valves are now the default style of valve for use in power plants.
Since the flurry of pressure-seal patent activity of the 40’s and early 50’s, valve design work has been focused on other types of valves, particularly ball and butterfly valves. As far as design innovation goes, the gate valve may have passed its prime, but its popularity with piping designers, cost-conscious purchasing agents and plant engineers is still very high.