| # | Country | Total Patents | |
|---|---|---|---|
| #1 | United States | 21 | |
| #2 | Canada | 1 |
| # | Industry | |
|---|---|---|
| #1 | Engines, pumps and turbines | |
| #2 | Machines | |
| #3 | Chemical engineering | |
| #4 | Environmental technology | |
| #5 | Transport |
| # | Technology | |
|---|---|---|
| #1 | Supplying combustion engines | |
| #2 | Unspecified technologies | |
| #3 | Separation | |
| #4 | Gas-flow silencers for machines | |
| #5 | Vehicle seats | |
| #6 | Pumps | |
| #7 | Cyclones |
| # | Name | Total Patents |
|---|---|---|
| #1 | Donaldson Frank A | 22 |
| #2 | Enblom John C | 1 |
| Publication | Filing date | Title |
|---|---|---|
| US2391887A | Two-way air cleaner for air compressors | |
| US2219176A | Backfire oil trap | |
| US2193479A | Centrifugal air cleaner | |
| US2206718A | Backfire oil trap for air cleaners | |
| US2203407A | Radiator and air cleaner assembly | |
| US2053603A | Air cleaner | |
| US2072548A | Air cleaner | |
| US1992025A | Backfire oil trap for air cleaners | |
| US1926841A | Air cleaner | |
| US1850343A | Air cleaner | |
| US1787235A | Air cleaner and coupling | |
| US1811043A | Spark arrester for internal combustion engines | |
| US1831805A | Spark arrester for internal combustion engines | |
| US1759978A | Spring implement seat | |
| US1641746A | Air cleaner | |
| US1755319A | Air cleaner | |
| US1669413A | Air cleaner | |
| US1513035A | Air cleaner | |
| US1513036A | Air cleaner | |
| US1556592A | Air cleaner |