| 摘要 |
PURPOSE:To enable the detection of purity of a liquid properly in an accurate and simple manner, by propagating light from an optical fiber with the liquid to be detected brought into direct contact with the core thereof. CONSTITUTION:Water is attached to the core of an optical fiber 3, light is made to propagate through the fiber 3 under the normal temperature and the signal level detected here is inputted into a memory circuit 21 to be a reference signal for correction. After the fiber 3 is immersed into a container filled with a new oil such as soybean oil, it is pulled up and the level of the detection signal obtained under the normal temperature to be memorized into the circuit 21. The memorization of the signal for the correction and the signal levels corresponding to refractive indexes of new oils as respective frying oils are done sequently with a changeover switch 27. Moreover, when a need arises for checking the deterioration in the frying oils, the switch 27 is changed over to match the kind of the frying oil to be detected, the fiber 3 is immersed into the container full of the drying oil and then, pulled up. Then, the light propagating through the fiber 3 under the normal temperature is outputted to a comparator circuit 23, which compares it with a reference value from the circuit 21 and outputs the resulting difference to a display unit 31.
|
