Ralf Steffens
17Patents
8h-index
19Co-inventors
69Inventor score
Filing activity: May 11, 1988 → Sep 14, 2021
Most-cited inventions
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US5767635A | Displacement machine with electronic motor synchronization | Mechanical Engineering; Lighting; Heating | 58 | Expired |
| US5152684A | Rotor profile for a Roots vacuum pump | Mechanical Engineering; Lighting; Heating | 23 | Expired |
| US6666672B1 | Drive mechanism for a screw pump | Emerging Cross-Sectional Technologies | 15 | Expired |
| US4940398A | Twin-shaft, multiple-stage vacuum pump with the shafts vertically disposed | Mechanical Engineering; Lighting; Heating | 13 | Expired |
| US5924855A | Screw compressor with cooling | Mechanical Engineering; Lighting; Heating | 13 | Expired |
| US5904473A | Vacuum pump | Mechanical Engineering; Lighting; Heating | 11 | Expired |
| US4974318A | Method of making a dual-shaft machine | Emerging Cross-Sectional Technologies | 10 | Expired |
| US6497563B1 | Dry-compressing screw pump having cooling medium through hollow rotor spindles | Mechanical Engineering; Lighting; Heating | 8 | Expired |
| US4983107A | Multistage rotary piston vacuum pump having sleeves to fix shaft positions | Mechanical Engineering; Lighting; Heating | 7 | Expired |
| US4917583A | Bearing support for a twin-shaft pump | Mechanical Engineering; Lighting; Heating | 6 | Expired |
| US7056108B2 | Cooled screw-type vacuum pump | Mechanical Engineering; Lighting; Heating | 5 | Expired |
| US5035590A | Double-shaft vacuum pump with synchronization gears | Emerging Cross-Sectional Technologies | 3 | Expired |
| US4915194A | Lubricating oil feed system | Mechanical Engineering; Lighting; Heating | 3 | Expired |
| US8876506B2 | Displacement pump with internal compression | Mechanical Engineering; Lighting; Heating | 1 | Active |
| US10337515B2 | Spindle compressor using refrigerant cooling for housing and rotor | Mechanical Engineering; Lighting; Heating | 0 | Active |
| US12061023B2 | Water-based refrigerant for a thermal working machine and thermal working machine having such a refrigerant | Mechanical Engineering; Lighting; Heating | 0 | Active |
| US12012961B2 | Volume ratio for a R718* compressor | Mechanical Engineering; Lighting; Heating | 0 | Active |
Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.