| Patents for George B. Duffield |
Patents 1 -
7
of 7
      |
| Number | Date | Patentee | Title | Type |
| 1,629,449 | May 17, 1927 | G.B. Duffield | Valve Operating Device | valves |
| 1,661,131 | Feb. 28, 1928 | G.B. Duffield | Expansible Collapsible Element | steam engine packing |
| 1,719,801 | Jul. 02, 1929 | G.B. Duffield | Valve | valves |
| 1,865,560 | Jul. 05, 1932 | G.B. Duffield | Pop Valve | steam safety valves |
| 2,008,323 | Jul. 16, 1935 | G.B. Duffield | Control Device | industrial control apparatus |
| 2,167,433 | Jul. 25, 1939 | G.B. Duffield | Air Vent Valve | valves |
| 2,183,488 | Dec. 12, 1939 | G.B. Duffield | Closure | heating apparatus |
