| 摘要 |
<p>We have found that foam generated from an aqueous medium can have a thermal insulating effect. The creation of a substantial volume of foam on the surface of an aqueous medium can reduce the apparent thermal IR emission substantially when compared to that of the aqueous medium free of foam. This difference in infrared emission can be used to control the addition of a defoaming agent to control foam in the aqueous medium. In the foam control method of the invention, an infrared detector is used to measure the infrared emission of an aqueous medium free of foam and during operations such a measurement is compared to the infrared emission of the aqueous medium under foaming conditions. As foam develops on the surface of the aqueous medium, the apparent thermal infrared emission from the foam is less than that of the aqueous medium free of foam. As the thermal IR emissions drop as foam develops, the difference between the apparent temperature of the foam and the aqueous medium, as measured as infrared thermal emissions, drops. Such a drop in temperature can be used to trigger the addition of a defoaming agent which can substantially reduce foam volume. As the foam volume is reduced, the thermal infrared emission of the aqueous medium returns to a value near the thermal inverting emission of the aqueous medium without foam. At this point, the addition of a defoaming composition is substantially reduced or stopped. During the control method, a predetermined limit is established at which the defoaming composition is introduced into the aqueous medium. As long as the thermal infrared emission of the foamed aqueous medium is different than the thermal infrared emission of the aqueous medium without foam, the defoaming agent is continually added to the aqueous medium. Further, the method permits the amount of defoaming agent added to the aqueous medium to be in proportion to the difference in infrared emission above the preset predetermined limit.</p> |
