System and method for monitoring torsional vibrations and operating parameters of rotating shafts
First Claim
1. A system for analyzing rotational characteristics of a moving shaft having an axis of rotation and having a plurality of grid lines spaced about its circumference, comprising:
- optical detection means mountable in a fixed position proximate tot he shaft in the area of the grid lines for producing an output signal varying with movement of the grid lines relative to said optical detection means during rotation of the shaft, said optical detection means comprising;
incoherent radiation energy generation means for producing incoherent radiation energy and directing it against the grid lines;
Ronchi grid means for selectively passing radiation from said radiation energy generating means and having a plurality of radiation passage lines with spacing corresponding to the grid lines;
lens means for imaging a radiation image scattered from the shaft grid lines onto the plan of said Ronchi rid means; and
photodetection means for detecting the radiation level passing through said Ronchi grid means and generating an output signal representative of said movement of the grid lines; and
processing circuit means connected to said photodetection means for receiving said output signal and generating an output signal and generating an output indicative of recurring torsional vibrations in the shaft.
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Accused Products
Abstract
An optical system for monitor vibration, particularly applicable to power shafts in rotating power systems such as those found in trucks, naval vessels, turbogenerators, hydroelectric and nuclear generators, and helicopters, has an optical unit including IRLED radiation sources aimed at grid lines applied around the circumference of the shaft. The reflection of the radiation is imaged through lenses and a matching Ronchi grid onto a photodiode which produces a periodic wave signal from which indications of rotational irregularities can be derived. In one embodiment, duplicate radiation sources and imaging apparatus are arranged in diametric opposition across the shaft to permit compensation for pitch and plunge shaft vibration. In another preferred embodiment, a second, duplicate optical unit is located at a distance along the shaft from the first unit. The output signals of the two units are passed through a comparator and a EX-NOR gate, then low-pass filtered to produce a signal indicative of torsional deflection. Quadrature techniques can be used to provide shaft directional information. Also disclosed are a method and apparatus for precisely applying finely spaced grid lines to an existing shaft on site. A photosensitive material is applied to the shaft, and a strobe light synchronized to the rotation of the shaft exposes the photosensitive material as the shaft is rotated to create finely spaced grid lines on the material.
80 Citations
37 Claims
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1. A system for analyzing rotational characteristics of a moving shaft having an axis of rotation and having a plurality of grid lines spaced about its circumference, comprising:
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optical detection means mountable in a fixed position proximate tot he shaft in the area of the grid lines for producing an output signal varying with movement of the grid lines relative to said optical detection means during rotation of the shaft, said optical detection means comprising; incoherent radiation energy generation means for producing incoherent radiation energy and directing it against the grid lines; Ronchi grid means for selectively passing radiation from said radiation energy generating means and having a plurality of radiation passage lines with spacing corresponding to the grid lines; lens means for imaging a radiation image scattered from the shaft grid lines onto the plan of said Ronchi rid means; and photodetection means for detecting the radiation level passing through said Ronchi grid means and generating an output signal representative of said movement of the grid lines; and processing circuit means connected to said photodetection means for receiving said output signal and generating an output signal and generating an output indicative of recurring torsional vibrations in the shaft. - 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, 31, 32, 33, 34, 35, 36, 37)
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Specification