High temperature sensors

for gas turbines

PCB Piezotronics Ltd

PCB Piezotronics introduces high temperature accelerometers and pressure sensors that provide crucial information to enable diagnosis of potential problems, leading to an increase in turbine uptime and a decrease in unplanned maintenance, failures and accidents.

The high temperature accelerometer for gas turbine monitoring , series 357D90, is a charge output sensor that enables vibration measurement in extreme heat environments up to 649°C. With sensitivity of 5pC/g ±10%, measurement range of ±1000g peak and frequency range of 2.5kHz, the 357D90 is suited for use in the most demanding gas turbine measurement and monitoring applications.

The accelerometer is housed in an Inconel welded hermetically sealed package and features an integral hardline 3m cable. Weighing just 50 grams without cable, it features through-hole mounting and can interface directly with handheld data collectors for both permanent and route based applications.
 
The 176M03 charge output pressure sensor has been developed in response to market demands for piezoelectric devices that can detect and measure dynamic pressure phenomena in the presence of high static pressures. Turbine applications are often at 2068kPa static with dynamic pressures up to 34kPa. These sensors also need to be capable of operating in temperatures above 500°C.

The market demands are driven by regulatory pressures for modern power turbine manufacturers to achieve unprecedented reductions in emissions. In particular, NOx emissions have been reduced dramatically through new “lean burn” or “dry low NOx” designs. However, these advances have come at a price as the low fuel-to-air ratios of these combustors can result in coupled acoustic and heat release pressure oscillations. Even though the magnitude of these oscillations may be low, even small fluctuations of 1psi or less can cause high-cycle fatigue in metal parts downstream of the combustors.

The ATEX-CSA approved model 176M03 is suited to these environments with sensitivity to 2.5pC/kPa, ranges from 140 to 2760kPa and high temperature operation up to 535°C. Additional features include low-noise, in-line differential charge amplifier, case isolated and rugged 2-pin MIL connector.