Patent Update: Prior Commercial Use Can Affect Patentability


Inventors sometimes decide to apply for a patent after the invention has been shown to have commercial value. However, an early commercial use by the patent applicant, rather than a competitor, can be detrimental to a later-filed patent. The case of Heat On-The-Fly’s U.S. Patent No. 8,171,993 shows the difficulties this mistake can cause.

The invention in the ’993 patent relates to hydraulic fracturing (fracking). Fracking is a process to fracture the geological formation surrounding the wellbore of an oil or gas well to increase the formation’s porosity and, thus, enhance hydrocarbon production. An aqueous suspension of solids known as proppants, typically sand, is heated and pressurized, then injected into the wellbore to create cracks in the surrounding formation. The pressure is then released, but the proppants remain in place, holding the cracks open and, thereby, maintaining the higher porosity.

A major component of the cost of fracking is the use of frac tanks, in which the fracking fluid is heated in batches to a temperature high enough to compensate for the heat loss that occurs during transfer of the fluid from the tanks to the well. The ’993 invention reduces this cost by heating only a portion of the fracking fluid in a continuous process. The portion to be heated is drawn into a bypass loop on the water...

Author Bios: 

M. Henry Heines

M. Henry Heines, PhD, JD, (Email:; Website: is a patent attorney and an author, speaker, and consultant on patent-related topics for lawyers, as well as for scientists, engineers, and managers in technology companies, and has served as an expert witness in patent litigation. He began his career as a research engineer in the chemicals industry and worked in corporate patent practice before entering private practice, including 25 years as a partner in the firm now...Read more

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