| 1931 WESTINGHOUSE Back Up Whistle Application Valve |
| 1931 GRIESHABER Emergency Fuel Tank Sea Valve |
| 1931 AMERICAN VALVE METER COMPA Railway Switch |
| 1931 ALLAND Combined Valve Mixing Unit Patent 36338 |
| 1931 JOHNSON Piston Valve Structure Wind Instruments |
| 1931 AMERICAN PIANO CORP Valve Unit Patent Print |
| 1931 LODER Automatic Signal Whistle Valve Patent |
| 1931 GEORGE Valve Operating Mechanism Tanks Art |
| 1931 OLDS Piston Valve Wind Instruments Art |
| 1931 YORK Piston Valve Structure Wind Instruments |
| 1931 ANDREW A KRAMER Valve Operating Mechanism Tanks |
| 1931 HAMBRIC Shut Off Valve Control Tank Trucks |
| 1931 AEOLIAN Electromagnet Valve Art Print |
| 1931 WOODWARD LEWIS Organ Valve Patent Print Art |
| 1931 LEET Electromagnet Valve Device Patent |
| 1931 ELECTRIC BOAT CO Emergency Fuel Tank Sea Valve |
| 1931 US Automatic Air Distributing Valve Sander Systems |
| 1931 AMERICAN VALVE METER COMPA Switch Stand Art |
| 1931 BARROWS Pipe Organ Valve Action Patent |
| 1931 NEWELL Back Up Whistle Application Valve |
| 1931 OSCAR Valve Controlled Life Preserver |
| 1931 F E OLDS SON INC Piston Valve Wind Instruments |
| 1931 HICKMAN CLARENCE Valve Unit Patent Print |
| 1931 BARROWS Adjustable Pipe Organ Valve Patent |
| 1931 BARROWS Removable Pipe Organ Valve Patent |