| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Switzerland | 7 | |
| #2 | Germany | 5 | |
| #3 | France | 5 | |
| #4 | Austria | 3 | |
| #5 | Sweden | 2 | |
| #6 | United States | 2 |
| # | Industry | |
|---|---|---|
| #1 | Mechanical elements | |
| #2 | Machine tools | |
| #3 | Chemical engineering |
| # | Technology | |
|---|---|---|
| #1 | Pipes | |
| #2 | Nails | |
| #3 | Tools for connecting or disengaging | |
| #4 | Separation |
| # | Name | Total Patents |
|---|---|---|
| #1 | Hefel Walter | 9 |
| #2 | Walter Hefel | 3 |
| Publication | Filing date | Title |
|---|---|---|
| CH598853A5 | Bag type gas filter | |
| US4003590A | Fluid-tight flange coupling and method of making the same | |
| US3957261A | Holding device for workpieces and the like | |
| FR2107731A5 | Fabric filter - for dust removal | |
| CH526327A | Fabric filter - for sepn of dust from air or other gases |