| 摘要 |
<p>A power linkage for raising and lowering the skimming rake used to sweep surface scum from a rectangular or semicircular decantation tank. The tank is of the type in which the rake is mounted on a mobile chassis which bridges the tank and moves in one direction with the rake lowered to sweep the liq. surface and then back again with the rake raised to an inactive position. The rake is raised and lowered by a power linkage using an actuating jack. An air compressor serves an emulsion pump for shifting sludge from the bottom of the tank. The rake linkage actuating jack is now a pneumatic jack operated by low pressure air from the compressor serving the emulsion pump. The air pressure is pref. less than 0.4 bar and the pneumatic jack comprises a simple, deformable container made of resilient material, e.g. a corrugated, rubber bellows. Pref. as the mobile bridge chassis reaches each end of its travel, a pneumatic limit switch is triggered so that a pilot valve actuates the pneumatic jack. The skimmer is used to clean the top surface of liq. being treated in a sedimentation tank.</p> |
