| 摘要 |
<p>A fire hydrant of the "dry" barrel type having an improved means of draining the barrel after the hydrant has been used and the main hydrant valve closed. The hydrant is provided with a drain passageway from the interior of the barrel above the main hydrant valve to the exterior of the valve. A first valve means, which is automatically opened or closed by actuation of the main hydrant valve element, is arranged to close the drain passageway when the main hydrant valve element is open and to open the drain passageway when the main hydrant valve element is closed. A pressure responsive one-way check valve in series with the valve means in said drain passage is automatically actuated to open position by pressure of water when there is water in the hydrant barrel and the valve means in series therewith in the drain passageway is open. The one-way check valve automatically closes when the barrel is dry and prevents ingress of water and dirt, grit or other foreign matter from the exterior of each to the interior, thereby protecting the main hydrant valve and its associated operating mechanism.</p> |
