| 摘要 |
<p>A heater for controllably heating liquid in a container includes a substantially flat, elongated pad which is electrically non-conductive and is adapted to receive the liquid bearing container on one of its surfaces. An electrical heating device is embedded in the pad and is adapted to heat the end portions of the pad but not a central portion thereby defining heated and non-heated sections, respectively. A first thermostat, associated with the heating device, is in the nonheated section and is adapted to monitor the temperature if the container at its interface with the pad and limit the temperature to which the container can rise during heating. A second thermostat, associated with the heating device, is in the heated section and is adapted to monitor the temperature of the heated section and limit the temperature to which the heated section may rise during heating. The method includes placing a container with a prescribed amount of liquid on a surface of an electrically non-conductive heating pad having a controllable electrical heating device embedded therein. Heat is applied to the container from the end portions of the pad only, which constitute the heated section thereof, a centrally located portion of said pad being a non-heated section. The maximum temperature to which the interface of the container and the pad can rise during heating is limited to a first predetermined temperature; the maximum temperature to which the heated section can rise during heating is limited to a second predetermined temperature, the second predetermined temperature being higher than the first predetermined temperature. In this way, the liquid in the container is controllably heated to the desired temperature which is approximately that of the first predetermined temperature.</p> |
