摘要 |
In a technological process two liquids are available for heating purposes, of which the warmer one is to be chosen. For this purpose, the temperature of the two liquids is measured and the flow of the two liquids is controlled as a function of the temperatures by means of actuators. This control is carried out such that at a temperature of the colder liquid which is much lower than the temperature of the warmer liquid, the latter flow is utilized. When the temperature of the colder liquid approaches the temperature of the warmer liquid, the actuator for the colder liquid is slowly opened. In the case of equal liquid temperatures, both actuators are fully opened. If the temperature of the former colder liquid exceeds that of the former warmer liquid, the actuator of the formerly warmer liquid is slowly closed, while the actuator of the formerly colder liquid remains fully open. Sudden large temperature variances of the heating liquid are thereby avoided.
|