Pipes and tubular conduits
Patent class list (only not empty are listed)
Deeper subclasses:
| Class / Patent application number | Description | Number of patent applications / Date published |
|---|---|---|
| 138118000 | FLEXIBLE | 445 |
| 138103000 | COMBINED | 379 |
| 138140000 | DISTINCT LAYERS | 368 |
| 138097000 | REPAIRING | 227 |
| 138037000 | WITH FLOW REGULATORS AND/OR BAFFLES | 167 |
| 138026000 | WITH PRESSURE COMPENSATORS | 152 |
| 138089000 | WITH CLOSURES AND PLUGS | 143 |
| 138177000 | STRUCTURE | 136 |
| 138111000 | PLURAL DUCT | 78 |
| 138155000 | JOINED SECTIONS | 60 |
| 138096000 | END PROTECTORS | 42 |
| 138032000 | THAWING AND FREEZE PROTECTION | 40 |
| 138172000 | REINFORCED | 37 |
| 138156000 | LONGITUDINALLY SEAMED | 33 |
| 138036000 | WITH WEAR INDICATOR | 6 |
| 138154000 | SPIRALLY SEAMED | 6 |