| 摘要 |
<p>A tea making appliance 2 comprises a water heating vessel 4 provided with a thick film heater 24 on its base 20 and an infusion vessel 6 arranged thereon, containing in use a dose of tea leaves. A tube 8 extends down from the infusion vessel 6 into water heating vessel 4. As water in the water heating vessel 4 is heated, the vapour pressure in the vessel 4 increases, with vapour escaping from the vessel 4 through a valve unit 46. When the water begins to boil, a ball 50 in the valve unit 46 is forced by the vapour pressure against its seat 54 to close the valve, forcing heated water to flow through tube 8 into the infusion vessel 6. Once transfer of the water is complete, a control unit 72 operates to disconnect the power supply to the heater 24. The steam pressure in the water heating vessel 4 begins to fall, and valve 46 reopens, allowing infused tea to flow back into the water heating vessel 4. <IMAGE></p> |
