Turbine blade temperature detecting pyrometer

Claim 1

A pyrometer for receiving radiation over a wavelength range from a member emitting radiation as a function of temperature of the member, the pyrometer further receiving undesired radiation from a flame adjacent to the member, the flame having arange of flame temperatures substantially higher than the temperature of the member, and the pyrometer also receiving radiation at least once from a reference source having a reference temperature in the range of the flame temperatures, comprising: sensing means for receiving both the emitted and the undesired flame radiation and for providing first and second outputs, I u and I f , substantially proportional to the radiation received across different first and second segments respectively of the wavelength range; comparator means for receiving the first and second outputs and for providing a comparator output which is substantially proportional to an adjusted weighted difference , I u -KI f , between the first and second outputs, the weighting factor K being adjusted such that the comparator output has a reduced dependence on the undesired flame radiation; and output means for receiving the comparator output and for providing a pyrometer output indicative of the temperature as a nonlinear function of the comparator output; and wherein the weighting factor K has been adjusted such that the comparator output has been substantially nulled when the pyrometer received radiation from the reference radiation source.

Claim 3

A method of obtaining a pyrometer output indicative of a temperature of a member emitting radiation as a function of its temperature and received by a pyrometer over a wavelength range of the pyrometer, the pyrometer further receiving undesired radiation from a flame adjacent to the member at the same time that the radiation from the member is received, the flame having a range of flame temperatures substantially higher that the temperature of the member, and the pyrometer also receiving radiation at least once from a reference source having a reference temperature in the range of the flame temperatures, comprising the steps of: coupling the pyrometer to the reference source; sensing the reference radiation over different first and second segments of the wavelength range; providing a first output I u substantially proportional to reference radiation sensed across the first segment of the wavelength range; providing a second output I f substantially proportional to reference radiation sensed across the second segment of the wavelength range; providing a comparator output which is a weighted difference, I u -KI f , between the first and second outputs; adjusting the weighting factor K in the comparator output such that the comparator output is substantially nulled when the reference radiation is received; decoupling the pyrometer from the reference source and subsequently coupling the pyrometer to the emitted and undesired radiation; sensing both the emitted and undesired radiation over the first and second segments of the wavelength range; providing the first output I u while the emitted and undesired radiation and sensed; providing the second output I f while the emitted and undesired radiation are sensed; providing the comparator output while the emitted and undesired radiation are being sensed; and providing a pyrometer output nonlinear as a function of the comparator output, the pyrometer output indicating temperature based on the comparator output such that the effects of the undesired radiation are substantially reduced.

Claim 4

A method of obtaining a pyrometer output indicative of a temperature of a member emitting radiation as a function of its temperature and received by a pyrometer over a wavelength range of the pyrometer, the pyrometer further receiving undesired radiation from a flame adjacent to the member at the same time that the radiation from the member is received, the flame having a range of flame temperatures substantially higher that the temperature of the member, and the pyrometer also receiving radiation at least once from a reference source having a reference temperature in the range of the flame temperatures, comprising the steps of: coupling the pyrometer to the reference source; sensing the reference radiation over different first and second segments of the wavelength range; providing a first output I u substantially proportional to reference radiation sensed across the first segment of the wavelength range; providing a second output I f substantially proportional to reference radiation sensed across the second segment of the wavelength range; providing a comparator output which is a weighted difference, I u -KI f , between the first and second outputs; adjusting the weighting factor K in the comparator output such that the comparator output is substantially nulled when the reference radiation is received; decoupling the pyrometer from the reference source and subsequently coupling the pyrometer to the emitted and undesired radiation; sensing both the emitted and undesired radiation over the first and second segments of the wavelength range; providing the first output I u while the emitted and undesired radiation and sensed; providing the second output I f while the emitted and undesired radiation are sensed; providing the comparator output while the emitted and undesired radiation are being sensed; and providing a pyrometer output nonlinear as a function of the comparator output, the pyrometer output indicating temperature based on the comparator output such that the effects of the undesired radiation are substantially reduced.