| 摘要 |
<p>A drone for internal scouring of underground pipes, sewers etc. by means of high pressure water jets involves jets on one or more rotating arms supplied with water at outputs of at least 200 litres/min. at at least 300 bars, where the water is transferred through a rotary bearing designed to allow a slight liq. loss so that the rotor can turn freely. Pref. the bearing sleeve is made of a chemically modified form of polyethylene terephthalate known as "Ertalyte" (RTM), having a density of 1.38, being hard, rigid and with low water absorption and coefficient of friction characteristics. Used for systems where the high pressure hose may also serve as the drag line. The carriage may be fixed to ride ledges within a standard passage or may be self-compensating to suit non-circular passages requiring jets and rotors at more than one level.</p> |
