| 摘要 |
1,187,331. Temperature measuring. GENERAL ELECTRIC CO. Jan.22, 1968 [April 21, 1967], No.3325/68. Heading G1A. [Also in Division G3] The temperature of an inaccessible surface of a body is measured by investigating two spectral bands of the radiation from a proximate accessible surface by means of a fibre optic guide, the transmitted radiant energy being converted into a series of electrical pulses alternate ones of which represent the amplitude of the respective spectral components and the pulses representing the respective bands being separated and compared by a comparison device in which adjustment to give a null output provides the temperature indication. The temperature of the hottest spot on a cutting tool 10, Fig. 3, is determined by such apparatus, the fibre optic guide being inserted in a hole in the bottom of the tool beneath the hot spot and its remote end applying infrared to a detector 35 through a disc 31 comprising a pair of rotating different filters 32, 33. The pulses are separated by an FET switch 43 controlled by pulses from an arc-responsive presence or absence optical system 37-40 associated with disc 31, and applied to differential amplifier 51 through peak-topeak detector 46 and LP filters 45, 47. The temperature is indicated by a nulling unit 48. The fibre optic may be let into a hole in the cutting member support opposite a hole beneath the hottest spot in the cutting member itself and separate optics within a milling cutter may be air coupled to a fixed fibre optic guide. The output may be used to regulate tool cutting speed to obtain a desired tool temperature. The guides may be of glass or quartz fibres according to the temperature to be measured, the former being used in conjunction with gallium arsenide or cadmium sulfide detectors, and the latter with lead sulfide or indium arsenide. The filters may be made to reciprocate or alternatively the end of the light guide may be moved. |
