| 摘要 |
PURPOSE:To quickly detect the boiling start in a lower vessel by directly detecting the heat of the steam, when the water in the lower vessel is boiled, and its steam flows into an upper vessel, by a boiling detecting means. CONSTITUTION:When the water in a lower vessel 6 is boiled, and the hot water starts to rise in a water passing tube 10, the steam of the hot water rises into an upper vessel 7 and makes contact with a thermosensitive plate 18, and the heat of the steam is detected by a thermal reed switch 19. When the temperature of the thermal reed switch 19 reaches a preset fixed temperature, its contact is opened to release the excitation of a relay, whereby the relay contact is opened to stop the current carrying to a heater 4 and a pilot lamp 32. Although the thermal reed switch is low in precision of temperature detection, compared with a thermistor, it directly detects the heat of the steam in the upper vessel 7, and can quickly detect the start of boiling in the lower vessel 6 even when the temperature detecting precision is low. Therefore, the extracting time of coffee is never prolonged, and coffee of mellow flavor can be extracted. |
