Abb Research Ltd.

Bbc Brown Boveri Ag

Thomas Dobler

Ken Yves Haffner

Georg Mastner

Martin Maschek

Wolfgang Evers

Urs Ammann

The present invention discloses a high temperature pyrometer 20 which is suitable, in particular, for temperature measurement in a gas turbine. The pyrometer comprises a flexible lightguiding measuring probe 21 with a microlens 22 resistant to high temperatures and with an optic fiber 24 composed of quartz or sapphire, said microlens and said fiber being provided with a gold sheathing 25, 26 and/or a protective capillary 27, 28. The heat radiation is evaluated in a remote detector 32 having measuring electronics 33 connected to it. The pyrometer 20 is distinguished by compactness, high temperature capability, flexibility, versatile installability and high measuring accuracy. The invention also relates to a development of the pyrometer 20 for gas turbines, to a gas turbine with a pyrometer 20 according to the invention, and to a method for monitoring a gas turbine with the aid of a pyrometer 20. Explanations are given of ways in which the measuring probe 21 can be fitted in guide blades 34, 48 and by means of which accurate temperature measurements are possible on moving and guide blades 34, 35, 48, 49 in low pressure and high pressure turbines. The operating safety and the efficiency of gas turbines can thereby be increased.

Optic pyrometer for gas turbines

Measurement value signals (S1), for example from a signal transmitter which is located at high-voltage potential, which are transmitted by a signal transmitter (1) with a transmit diode (6) on the high voltage side via an optical waveguide (8) to a signal receiver (9) with a photodiode (10) at ground potential, are subject to an optical signal attenuation along the way. To ensure automatic attenuation compensation both for alternating and for direct voltage measurement signals (S1), a reference direct current (I.sub.REF) is fed back to the transmit diode (6). The transmission system is calibrated before each measurement. During this process, the input of an amplifier (4) of the signal transmitter (1) is connected to reference potential (U0) via a switch (3) and the gain factor of the signal receiver (9) is controlled in such a manner that its output signal (S9) is equal to a predeterminable reference voltage (U.sub.REF). The output signal (S14) of a differential amplifier (14) is supplied via a lowpass filter (16) and a 1st post amplifier (17) to an instantaneous-value memory (18), the output signal (S18) of which controls the gain factor. After the calibrated state has been reached, the closed-loop control circuit is interrupted so that the gain factor remains constant until a new calibration is performed. The gain factor can be adjusted via electrically, electromechanically or optically controllable resistances or a multiplier or via the bias voltage of an avalanche photodiode (10).

Method and device for automatic compensation of the attenuation of a

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Wurenlos, Switzerland

Thomas Dobler