| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Germany | 42 | |
| #2 | United States | 2 | |
| #3 | United Kingdom | 1 |
| # | Industry | |
|---|---|---|
| #1 | Basic materials chemistry | |
| #2 | Control | |
| #3 | Chemical engineering | |
| #4 | Mechanical elements | |
| #5 | Electrical machinery and energy | |
| #6 | Machines | |
| #7 | Thermal processes |
| # | Name | Total Patents |
|---|---|---|
| #1 | Bergfeld Karl | 8 |
| #2 | Karl Bergfeld | 2 |
| #3 | Kremser Dr Leo | 1 |
| Publication | Filing date | Title |
|---|---|---|
| DE683592C | Standing retort for generating strong gas from younger fuels | |
| DE629384C | Process for the hot carburizing of gases | |
| GB303903A | Gas pressure regulators | |
| US1812767A | Gas washer | |
| US1756969A | Coal-carbonizing apparatus for the extraction of bituminous materials | |
| DE443579C | Cooler and cooler combined in one column | |
| DE502407C | Gas pressure regulator | |
| DE479098C | Jet pipe regulator, especially for regulating gas or steam pressure |