| 摘要 |
<p>A shower comprises a slug (24) located in the water passage and movable in response to the rate of flow of water through the passage, a wave emitter (25) and a wave detector (26) so arranged as to detect movement of the slug through the disturbance produced by the slug on the transmission of waves between the emitter and detector, and an electrical switch means responsive to the output of the wave detector and controlling the electrical supply to the heating element assembly. <IMAGE></p> |
