US 5,511,426 A · Process and device for measuring operating turbine blade vibrations

Abstract

A process and a device for the optical measurement of vibrations of rotating turbine blades moving with a specified speed of rotation. In one embodiment, the process comprises the steps of generating three reference signals in response to the detection, by an optical detector, of the passing of a marking made on the hub of a turbine wheel; detecting measurement signals, by another optical detector, in response to the passing of another marking made on at least one of the parts of a turbine blade, the blade undergoing oscillation; determining the time offsets existing between each of the reference signals and each of the measurement signals, these offsets being, in the absence of oscillations of the blade, zero or equal to specified constant values; and calculating the amplitude, frequency and phase components of blade vibration from the various offsets recorded.

Claims37

Dependent claims

A method for optically measuring vibrations in rotating turbine blades, each of said turbine blades being mounted on a hub integral with a shaft of a turbine wheel, each said blade comprising at least one flank disposed in a plane parallel to the midplane of said hub and a topside disposed in a plane parallel to the tangent plane of said hub, said turbine wheel moving with a specified speed of rotation, said method comprising the steps of:

generating three reference signals in response to the detection of the passing of a first marking made on said hub of the turbine wheel by a first optical detector;
detecting the passing of at least a third marking made on said topside of said blade, by a third optical detector and generating measurement signals in response thereto, said blade undergoing oscillation;
determining a plurality of time offsets between respective ones of each of said reference signals and each of said measurement signals, each said time offset being, in the absence of oscillations of said blade, equal to one of zero or a specified constant value;
and
calculating the amplitude, frequency and phase components of transverse and torsional blade vibrations from said plurality of time offsets.

2 more elements

A method for optically measuring vibrations in rotating turbine blades, each of said turbine blades being mounted on a hub integral with a shaft of a turbine wheel and each said blade comprising at least one flank disposed in a plane parallel to the midplane of said hub and a topside disposed in a plane parallel to a tangent plane of said hub, said turbine wheel moving with a specified speed of rotation and said turbine blades undergoing oscillation, said method comprising the steps of:

generating, with a first optical detector, three reference signals in response to detection of a passing of a first marking made on said hub of said turbine wheel;
detecting first measurement signals in response to passing of a second marking, made on said flank of each said blade, by a second optical detector;
detecting second measurement signals in response to passing of a third marking, made on said topside of each said blade, by a third optical detector;
determining a plurality of time offsets between a respective each of said reference signals and each of said measurement signals, each said time offset being, in the absence of oscillations of said turbine blades, equal to one of zero or a specified constant value;
and
calculating the amplitude, frequency and phase components of tangential transverse and torsional blade oscillations from said time offsets.

3 more elements

Dependencies are inferred from the claim text.

Process and device for measuring operating turbine blade vibrations

Life of this patent

Process and device for measuring operating turbine blade vibrations

Life of this patent

Abstract

Claims37