The Knife Gate Valve began its journey in the Swedish Pulp and Paper industry in the 1920s. The market demanded an inexpensive valve for pulp stock applications, and a revolutionary valve design for the era was born. Known as the Knife Gate Valve, this new technology was capable of low pressure unidirectional general purpose isolation.
The simplistic and inexpensive design did have its problems. The hypothesis that the pulp stock in the water slurry would dewater around the closed gate and seat, thus forming a tighter seal resulted in extremely high allowable leakage rates and fugitive emissions (leakage both inside and outside the piping system). Unfortunately, the original design often acted more as a sieve than a valve.
The 1950s saw a new patent for the Knife Gate Valve in the U.S. From here, a variety of designs (generations of knife gates) began to improve the functionality and capabilities of the valve. A fifth generation knife gate was invented in Switzerland in the 1960s, which became known as the Guided Shear Gate (GSG). Of the five generations of Knife Gate Valves, only the GSG was designed to actually “cut”.
