Contributor

Static control expert Dr. Kelly Robinson, PE, IEEE Fellow, President of Electrostatic Answers, has 25+ years of experience in problem-solving and consulting. To learn more about Dr. Robinson or Electrostatic Answers, visit: www.electrostaticanswers.com

First Static Dissipater

Why was the first static dissipater needed? And, who was the inventor?

Two industries drove the development of static dissipaters; printing and textile manufacturing. High speed printing on a continuous web was enabled by the rotary printing press. In 1847, Richard March Hoe patented an improved rotary drum printing press (US Patent 5,199).

rotary printing press

It took nearly 60 year for static to grow from merely a nuisance into a problem that required a solution. Several early pioneers built the foundation for modern static control.

A prolific inventor opened the modern age of static control for roll-to-roll operations. The first static dissipater was patented in June 1906 by William Henry Chapman of the Chapman Electric Neutralizer Company, Portland, Maine (US 824,339). His device had two wires, one positive and one negative, powered by a Wimshurst machine, an early static generator.

first active dissipater

 The first passive static dissipater was patented by William L. Hardwicke, Richmond, Virginia in November 1906 (US 836,576). His design of an array of grounded pins is still widely used today.

first passive dissipater

William Chapman proved to be a prolific inventor. In November 1909, he patented the first grid controlled corona ionizer (US 940,429). Grid controlled ionizers are still used for some coating applications requiring excellent static control and in imaging applications such as copiers and laser printers.

grid controlled corona charger

And, Chapman patented the first shockless static bar (US 940,431) in November 1909. His invention was to capacitively couple the pins of the static bar with the AC voltage source. This effective design is still used today in some shockless static bars.

shockless static bar

In another visionary invention, John S. Thompson, Chicago, Illinois in December 1914 patented the first static dissipater instrumented to indicate activity using a spark gap. He connected a passive static brush to a capacitor that stored electrical charge. The voltage on the capacitor increased as the brush dissipated static. A spark across an air gap indicated activity when the voltage reached the necessary, high level.

instrumented passive dissipater

I invite you to share your comments on this blog below. And, please feel free to suggest topics for future blogs.

My email address is:

Kelly.Robinson@ElectrostaticAnswers.com

Please feel free to visit my website:

www.ElectrostaticAnswers.com


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