| 摘要 |
<p>A hot-water-actuated espresso coffee maker has a chamber receiving a quantity of hot water and a piston. An actuator forces the piston through at least part of the chamber so as to deliver hot water under pressure through ground coffee. The actuator includes a shape-memory element configured such that, when a temperature of the element is raised above a transition temperature, the shape-memory element undergoes a phase change so as to become biased towards a predefined spring configuration, thereby applying force to the piston. A flow-guide element helps define a flow path at least partially blocking an inflow of hot water from reaching the shape- memory element until at least a majority of the chamber has been filled. The inflow of hot water sequentially fills the chamber and then heats the shape-memory element above the transition temperature.</p> |
