COUNCIL FOR THE PREPARATION OF HEALTH DRINKS

摘要

An apparatus is provided (1) for preparing a hot beverage, comprising a water reservoir (3), means for removing and heating water from the reservoir and transferring it into a brewing chamber (5), and a light-transmissive jug (9) for catching hot liquid emerging from the brewing chamber (5), a wall (13) of the jug (9) being provided with optical means (15) for indicating the volume of liquid contained in the jug (9), wherein the optical means (15) comprise a first graduated scale (159) and a second graduated scale (153), the first scale (159) being clearly visible only when the jug wall temperature is below a reference temperature To and the second scale (153) being clearly visible only when the jug wall temperature is above the reference temperature To, whereby the reference temperature To is within the range of 25 DEG C.To80 DEG C., the ratio of the pitch of graduations in the second scale (153) to the pitch of corresponding graduations in the first scale (159) being approximately equal to the liquid yield ratio (RL) of the apparatus. In practice, the optical means (15) may comprise a film (155) of polymer-dispersed liquid crystalline (PDLC) material disposed between the first (159) and second (153) graduated scales.