Photoelectric ice accumulation monitor using dual detectors
First Claim
1. An ice accumulation monitor for detecting the formation of ice on a surface and measuring the amount of ice accumulated, comprising:
- (a) a prism that is transparent to radiation emitted by an emitter and with one surface of the prism exposed to ice accumulation and this surface positioned in the same plane as the surface on which ice accumulation is to be measured;
(b) an emitter of pulsed electromagnetic radiation with means for maintaining the emission intensity independent of temperature, which emitter is oriented so that at the exposed prism surface the emitted radiation is totally reflected within the prism when the exposed prism surface is bare, but at the exposed prism surface the emitted radiation is only partially reflected within the prism when the exposed prism surface is covered with ice and the balance of the emitted radiation is transmitted into the ice layer and reflected at the subsequent ice-air interface;
(c) two radiation detectors located to detect radiation reflected within the prism with one radiation detector located closer to the exposed surface than the other radiation detector; and
(d) a temperature sensor located in the transparent prism near the exposed surface, whereby upper and lower bounds of ice accumulation are measured by comparing outputs from each radiation detector with a calibration curve for that radiation detector.
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Abstract
Apparatus and method using internal reflection of electromagnetic radiation to detect ice or water on pavements or other surfaces and to continuously measure the thickness of the accumulation. A prism which is transparent to pulses of electromagnetic radiation from an emitter is mounted in the pavement with an exposed prism surface flush with, and in the plane of the surface being monitored for the accumulation. Radiation from an emitter is directed at the exposed prism surface at an angle so that the radiation is totally reflected when the exposed surface is bare, but only partially reflected when there is an accumulation. Radiation detectors are positioned so that changes in the intensity of internally-reflected radiation are measured and interpreted to detect the onset of an accumulation, measure the thickness of the accumulation, distinguish accumulations of ice from accumulations of water, and distinguish accumulations of mud or dirt from accumulations of ice or water.
35 Citations
30 Claims
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1. An ice accumulation monitor for detecting the formation of ice on a surface and measuring the amount of ice accumulated, comprising:
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(a) a prism that is transparent to radiation emitted by an emitter and with one surface of the prism exposed to ice accumulation and this surface positioned in the same plane as the surface on which ice accumulation is to be measured; (b) an emitter of pulsed electromagnetic radiation with means for maintaining the emission intensity independent of temperature, which emitter is oriented so that at the exposed prism surface the emitted radiation is totally reflected within the prism when the exposed prism surface is bare, but at the exposed prism surface the emitted radiation is only partially reflected within the prism when the exposed prism surface is covered with ice and the balance of the emitted radiation is transmitted into the ice layer and reflected at the subsequent ice-air interface; (c) two radiation detectors located to detect radiation reflected within the prism with one radiation detector located closer to the exposed surface than the other radiation detector; and (d) a temperature sensor located in the transparent prism near the exposed surface, whereby upper and lower bounds of ice accumulation are measured by comparing outputs from each radiation detector with a calibration curve for that radiation detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification