Abstract
We have been studying on a dynamic observation system to monitor the aged deterioration of water-soluble coolant. The aged deterioration of coolant changes the color and turbidity of coolant and affects the reflectance, absorbance and transmittance of light. An observation technique using red, green and blue LED lights was proposed as a nondestructive measured method to detect the color and turbidity change. In the case of less than 2% of oil content in the coolant, the concentration of oil content and impurities could be monitored separately from the reflectance of red LED and blue LED lights. While the colored LED lights showed a similar reflectance independent of the oil content in the water-soluble coolant and color of light on condition that the oil content is over 5%.
