Method of detecting conductive material contained in glass fiber by detecting changes in amplitude and frequency of an oscillator and detecting apparatus therefor

Claim 1

A method of detecting conductive material in a glass fiber, which is minute and contained in a very small quantity therein, under the condition that the glass fiber is moved at relatively high speed, the method comprising the steps of providing an oscillator including a reactance element set in an oscillating state which has a predetermined oscillating amplitude value and a predetermined oscillating frequency value existing in a range of a relatively high frequency, moving the glass fiber, which may contain the conductive material to be detected, in the vicinity of the reactance element, detecting instantaneous changes respectively in the oscillating amplitude and oscillating frequency in response to such glass movement, in which the corresponding value is changed from the respective predetermined value to a different value of increasing or decreasing direction relative to the predetermined value, and determining instantaneously the presence of such conductive material upon simultaneously determining that a detected change of the oscillating state is caused by the conductive material contained in the glass fiber, by detecting when the direction of the detected change in the oscillating amplitude and the direction of the simultaneously detected change in oscillating frequency are identical to each other.

Claim 2

A method of detecting conductive material in a glass fiber, which is minute and contained in a very small quantity therein, under the condition that the glass fiber is moved at relatively high speed, the method comprising the steps of providing an oscillator including a reactance element set in an oscillating state which has a predetermined oscillating amplitude value and a predetermined oscillating frequency value existing in a range of a relatively high frequency, moving the glass fiber, which may contain the conductive material to be detected, in the vicinity of the reactance element, detecting instantaneous changes respectively in the oscillating amplitude and oscillating frequency in response to such glass movement, in which the corresponding value is changed from the respective predetermined value to a different value of increasing or decreasing direction relative to the predetermined value, and determining instantaneously the presence of such conductive material upon simultaneously determining that a detected change of the oscillating state is caused by the conductive material contained in the glass fiber, by detecting when the direction of the detected change in the oscillating amplitude and the direction of the simultaneously detected change in oscillating frequency are identical to each other.

Claim 8

An apparatus for detecting conductive material in a glass fiber, which is minute and contained in a very small quantity therein, under the condition that the glass fiber is moved at relatively high speed, the apparatus comprising a reactance element disposed for positioning in the vicinity of a moving portion of the glass fiber, an LC oscillator including the reactance element as a circuit component, which is set in an oscillating state which has a predetermined oscillating amplitude value and a predetermined oscillating frequency value existing in a ranged of a relatively high frequency, an AM detector coupled to said oscillator for detecting an instantaneous change from the predetermined value of the oscillating amplitude of the output signal from the LC oscillator, to a different value of increasing or decreasing direction relative to the predetermined value and producing an AM detection signal in response to detection of said instantaneous amplitude change, an FM detector coupled to said oscillator for detecting an instantaneous change from the predetermined value of the oscillating frequency of the output signal from the LC oscillator, to a different value of increasing or decreasing direction relative to the predetermined value and providing an FM detecting signal in response to detection of said instantaneous frequency change, a composite wave generator for summing up the AM and FM detection signals and producing a composite signal, and a comparator for comparing the composite signal with a reference value and producing a conductive material detecting signal when the composite signal is the sum of an oscillating amplitude whose detected change in value and an oscillating frequency whose simultaneously detected change in value are of identical direction.

Claim 9

An apparatus for detecting conductive material in a glass fiber, which is minute and contained in a very small quantity therein, under the condition that the glass fiber is moved at relatively high speed, the apparatus comprising a reactance element disposed for positioning in the vicinity of a moving portion of the glass fiber, an LC oscillator including the reactance element as a circuit component, which is set in an oscillating state which has a predetermined oscillating amplitude value and a predetermined oscillating frequency value existing in a ranged of a relatively high frequency, an AM detector coupled to said oscillator for detecting an instantaneous change from the predetermined value of the oscillating amplitude of the output signal from the LC oscillator, to a different value of increasing or decreasing direction relative to the predetermined value and producing an AM detection signal in response to detection of said instantaneous amplitude change, an FM detector coupled to said oscillator for detecting an instantaneous change from the predetermined value of the oscillating frequency of the output signal from the LC oscillator, to a different value of increasing or decreasing direction relative to the predetermined value and providing an FM detecting signal in response to detection of said instantaneous frequency change, a composite wave generator for summing up the AM and FM detection signals and producing a composite signal, and a comparator for comparing the composite signal with a reference value and producing a conductive material detecting signal when the composite signal is the sum of an oscillating amplitude whose detected change in value and an oscillating frequency whose simultaneously detected change in value are of identical direction.