DH

Dennis J. Helfritch

RE Research-Cottrell: 2 patents #1 of 2Top 50%
📍 Rapid City, SD: #1 of 9 inventorsTop 15%
🗺 South Dakota: #1 of 62 inventorsTop 2%
Overall (1989): #29,146 of 140,708Top 25%
2
Patents 1989

Issued Patents 1989

Showing 1–2 of 2 patents

Patent #TitleCo-InventorsDate
4883570 Apparatus and method for enhanced chemical processing in high pressure and atmospheric plasmas produced by high frequency electromagnetic waves Philip Efthimion 1989-11-28
4832806 Radiation for the selective destruction of toxic molecules on solid surfaces 1989-05-23