| 摘要 |
<p>In the method according to the invention, an indicator element (33) is arranged above the outlet opening, i.e. above the valve (9) of a urinal, said indicator element degrading somewhat through each use and changing its colour after a prescribed number of uses. The colour change is an indicator which alerts the maintenance personnel that it is time to replace the valve (17). At the same time, it is also possible for cleaning and biodegradable substances to be added to the indicator element (33).</p> |
