| 摘要 |
<p>The instantaneous water heater comprises a water flow pipe; a first switch 11; a second switch 12; and a control dial operable to be rotated in order to selectively contact the first and second switches. When the control dial contacts the first switch a flow control valve such as a solenoid valve (2, figure 7) opens to permit passage of water through the water flow pipe. When the control dial contacts the second switch an electrical heating element (31, figure 2) heats water flowing through the water flow pipe. A delay control unit (6,7,7, figures 5-7) is arranged to prevent closure of the flow control valve upon contact between the first switch and the control dial being broken to ensure that residual heat in the heating element is dissipated. Ideally, the instantaneous heater includes a second electrical heating element activated when the control dial contacts a third switch 13. The switches are preferably micro-switches activated by respective first 161, second 162 and third 163 triggers located on a spindle 15 of the control dial. The delay control unit ideally comprises a temperature control switch (6, figure 5) or a time unit (7, figure 6) to control the delay.</p> |
