| 摘要 |
<p>A rotary arm sewage treatment bed has its rotary arms driven by an electrical drive system. The drive system comprises a driving ring (7) to which the arms are secured. The drive ring is driven by a friction belt (8), from a drive wheel (10). The drive wheel (10) is mounted on a pivoted carriage (18). A compressor (30) operates a piston/cylinder (36)/(34). In normal use, the piston (36) acts on the carriage (18) to cause tensioning of the belt (8), and thus enable drive. In the event of a supply failure, the piston is retracted by a return spring and the drive is disengaged, the carriage being pivoted such that the drive wheel is no longer in a position to tension the belt (8). The arms are then free to rotate under the reaction force of the sewage emitted, until the power supply is restored.</p> |
