| 摘要 |
<p>A sewage distributor arm comprises a hollow tube including an inlet and a series of spaced apart distributor nozzles along its length and, remote from the inlet a closure mounted within the tube so as to be rotatable about an axis perpendicular to the axis of the arm between open and closed positions. The arm may be constructed with the closure mounted within it or a cap including the closure may be provided for installation on existing distributor arms. The closure may be almost wholly spherical but with a face which in the closed position lies perpendicular to the axis of the tube and in the open position lies generally parallel to the tube wall. This closure is less susceptible to interference and damage by vandals than prior arrangements. <IMAGE></p> |
