| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Canada | 8 | |
| #2 | United States | 7 | |
| #3 | Australia | 5 | |
| #4 | South Africa | 4 | |
| #5 | United Kingdom | 3 | |
| #6 | Brazil | 2 | |
| #7 | Germany | 2 | |
| #8 | Sweden | 2 | |
| #9 | EPO (European Patent Office) | 1 | |
| #10 | Spain | 1 | |
| #11 | Peru | 1 |
| # | Industry | |
|---|---|---|
| #1 | Mechanical elements | |
| #2 | Machines | |
| #3 | Control |
| # | Technology | |
|---|---|---|
| #1 | Venting or aerating devices | |
| #2 | Unspecified technologies | |
| #3 | Systems controlling non-electric variables |
| # | Name | Total Patents |
|---|---|---|
| #1 | Clarkson Curtis W | 29 |
| #2 | Koll Larry F | 19 |
| #3 | Williams Nicholas J | 17 |
| #4 | Jennings Milton E | 7 |
| #5 | Mckavanagh Thomas P | 2 |
| #6 | Clarkson C W | 1 |
| #7 | Clarkson C | 1 |
| #8 | Clarkson John R | 1 |
| Publication | Filing date | Title |
|---|---|---|
| US5890700A | Gate valve | |
| CA2127057A1 | Line blind valve | |
| US5370149A | Line blind valve | |
| ZA9302100B | Gate valve | |
| US5271426A | Gate valve | |
| US4895181A | Gate valve | |
| US4846442A | Gate valve with lock ring | |
| US4688597A | Gate valve | |
| US4257447A | Gate valve | |
| GB1170821A | Fluid Control Valve | |
| CA826520A | Valve |