| 摘要 |
<p>Wet barrel fire hydrants which feature additional structure for reducing the potential that those with ill intent can foul municipal water supplies by introducing toxins or other materials into fire hydrants. Various embodiments include valves which close off portions of the hydrant or water conduit otherwise available for receipt of toxic or other materials when the fire hydrant nozzle cap is unscrewed and open and/or a pump is connected to the nozzle. Such valves preferably open automatically when water is flowing from the water supply through the nozzle, but close off portions of the barrel when the nozzle is open and water is not flowing through the nozzle.</p> |
