| 摘要 |
PCT No. PCT/EP93/01572 Sec. 371 Date Feb. 21, 1995 Sec. 102(e) Date Feb. 21, 1995 PCT Filed Jun. 21, 1993 PCT Pub. No. WO94/00045 PCT Pub. Date Jan. 6, 1994An espresso coffee maker is provided with a heat exchanger, a coffee dispenser unit and a water supply system in conjunction with the heat exchanger for supplying heated water to the coffee dispenser unit. The water supply system feeds cold water to the heat exchanger and heated water is delivered to the dispenser unit. A heated water return pipe is connected to the heat exchanger from the dispenser unit to form a recirculation circuit between the heat exchanger and the dispenser unit through which the heated water flows by natural convection to transfer heat from the heat exchanger to the dispenser unit. The water supply system includes at least one heat operated control valve incorporated in the recirculation circuit. The valve is provided with a chamber and a shutter is movable in the chamber to control the circulation of the water. A bias element made of a shape-memory material urges the shutter towards a normal position throttling down the transfer port when the temperature of the water through the recirculation circuit is above the transition temperature of the shape-memory material. |
