| 摘要 |
A drip coffee maker employs a temperature-deformable element (62) to control the flow of hot water by gravity from a reservoir and heater assembly (46). A stopper (56) controlled by the temperature-deformable element (62) near the bottom of the reservoir (48) seals a hole (58) in the bottom of the reservoir until a predetermined water temperature is attained in the vicinity of the temperature-deformable element (62). A heating element (50) near the walls of the reservoir (48) heats higher layers of water in the reservoir by convection leaving the water in the vicinity of the temperature-deformable element (62) relatively cooler. When the hole (58) is unsealed, the loss of the cooler water through the hole brings hotter water from above to provide regenerative control of the temperature-deformable element (62) for positive actuation. A discontinuous embodiment employs a small reservoir and heater assembly fed cooler water by gravity from a main reservoir above; water admitted during each filling of the small reservoir and heater assembly is heated and dispensed before a fresh supply of cool water is admitted. |
