Keystone International
🏢 View company profile →100Patents
0Active
100Granted
41Portfolio score
Filing activity: Jun 27, 1974 → Nov 22, 1999
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US3982725A | Valve actuator | Mechanical Engineering; Lighting; Heating | 66 | Expired |
| US5823228A | Valve manifold | Emerging Cross-Sectional Technologies | 46 | Expired |
| US5469805A | High visibility valve position indicator | Emerging Cross-Sectional Technologies | 46 | Expired |
| US5036884A | Mounting means for fluid pressure transmitters | Emerging Cross-Sectional Technologies | 40 | Expired |
| US4616803A | Declutchable valve override | Emerging Cross-Sectional Technologies | 40 | Expired |
| US4169543A | Amplitude responsive detector | Physics | 39 | Expired |
| US5579800A | Rotary valve position indicator and method | Emerging Cross-Sectional Technologies | 39 | Expired |
| US5292155A | Method and apparatus for mounting an instrument assembly on a main flow line | Mechanical Engineering; Lighting; Heating | 34 | Expired |
| US5054374A | Rotary actuator | Emerging Cross-Sectional Technologies | 33 | Expired |
| US5244183A | Fugitive emission sealing assembly | Emerging Cross-Sectional Technologies | 32 | Expired |
| US4846212A | Bleed valve assembly for double block and bleed system | Emerging Cross-Sectional Technologies | 32 | Expired |
| US5007330A | Rotary actuator and seal assembly for use therein | Emerging Cross-Sectional Technologies | 29 | Expired |
| US3985151A | Valve actuator | Emerging Cross-Sectional Technologies | 29 | Expired |
| US5313976A | Top entry ball valve and method of assembly | Emerging Cross-Sectional Technologies | 28 | Expired |
| US4570901A | Positioning assembly for use with rotatable valves | Emerging Cross-Sectional Technologies | 27 | Expired |
| USD398375S | Manifold | General | 26 | Expired |
| US5044257A | Rotary actuator and method for forming a rotary piston | Emerging Cross-Sectional Technologies | 26 | Expired |
| US4589281A | Material level detector and control | Physics | 26 | Expired |
| US4079746A | Valve assembly having adapter means | Emerging Cross-Sectional Technologies | 25 | Expired |
| US4685611A | Butterfly valve construction having a composite seat | Mechanical Engineering; Lighting; Heating | 24 | Expired |
| US4701938A | Data system | Electricity | 22 | Expired |
| US5518028A | Adjustable magnet carrier for a valve position indicator | Emerging Cross-Sectional Technologies | 21 | Expired |
| US4541612A | Rotatable shaft assembly | Emerging Cross-Sectional Technologies | 21 | Expired |
| US5494071A | Mounting system for pressure transmitters | Emerging Cross-Sectional Technologies | 20 | Expired |
| US4226118A | Level detector | Physics | 20 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.