Station probe for gas turbine engines

A station probe employed in a gas turbine engine includes a rake portion having a plurality of sensors for sensing conditions in the gas turbine engine. An environmental container attached to the rake portion includes signal conditioning circuitry that locally analyzes sensor signals received from the plurality of sensors to generate measured values, and a communication module for communicating the measured values to a control room.

BACKGROUND

The present invention is related to station probes employed in gas turbine engines.

Station probes are employed in gas turbine engines to test the operation of the engine, including monitoring of the temperature and/or pressure of the working fluid (i.e., airflow) through the engine. To gather this data, station probes are positioned at various locations circumferentially and axially within the gas turbine engine.

A typical station probe consists of a tube (known as a rake portion) that extends radially into the engine with a plurality of temperature sensors (e.g., thermocouples) and inlets opened to monitor pressure located along the length of the tube. Each temperature sensor is connected by wire to a remotely located control room. Likewise, each pressure inlet is connected via pressure line (e.g., hose) to the remotely located control room. The control room includes signal conditioning circuitry for interpreting the inputs received form the temperature sensors and/or pressure inlets. Drawbacks of this architecture include long lengths of wire and/or pressure lines to connect the sensors back to the control room, which is expensive and introduces the possibility of faults along the way. Furthermore, each sensor and/or pressure inlet must be manually connected and disconnected each time the engine is moved from one test stand to another, which is a time-consuming and error-prone process.

SUMMARY

A station probe employed in a gas turbine engine includes a rake portion having a plurality of sensors for sensing conditions in the gas turbine engine. An environmental container attached to the rake portion includes signal conditioning circuitry that locally analyzes sensor signals received from the plurality of sensors to generate measured values, and a communication module for communicating the measured values to a control room.

DETAILED DESCRIPTION

FIG. 1is an orthogonal view of station probe10according to an embodiment of the present invention. Station probe10includes rake portion12, environmental container14, power input16and cooling fluid input18. Rake portion12is tubular, with a plurality of sensor locations for mounting temperature sensors20and pressure sensor inlets22. Environmental container14houses sensor conditioning circuitry (shown inFIG. 2) for interpreting sensor signals received from temperature sensors20and pressure sensor inlets22mounted along rake portion12. For each temperature sensor20, a wire or pair of wires runs within the tubular portion of rake portion12to connect the temperature sensor to the sensor conditioning circuitry. With respect to pressure sensor inlets22, pressure lines run within the tubular portion of rake portion12to connect the pressure inlets to the sensor conditioning circuitry. With respect to the pressure signal provided by the pressure lines, a pressure transducer may be employed to convert the line pressure to an analog signal for provision to the sensor conditioning circuitry.

In one embodiment, station probe10would be mounted on an engine casing of a gas turbine engine, with rake portion12extending into the path of working fluid flowing through the gas turbine engine (i.e., the gas flow). Depending on the axial location of station probe10along the length of the gas turbine engine, temperatures may range from moderate (e.g., room temperature) to extreme (e.g., more than six hundred degrees Fahrenheit).

To maintain accurate measurements and prevent electronic component failure (i.e., accurate interpretation of signals provided by the sensors), the temperature within environmental container14should remain relatively constant despite the high temperatures to which station probe10is exposed. For example, in one embodiment temperature sensors20are thermocouples, with thermocouple wires connecting each sensor20to signal conditioning circuitry housed in environmental container14. The thermocouple includes a hot junction (i.e., portion of the sensor exposed along rake portion12) and a cold junction (located within environmental container14), wherein a voltage generated by the thermocouple is based on the temperature difference between the hot junction and the cold junction. To correctly interpret the temperature at the hot junction, the temperature at the cold junction must be tightly regulated.

To regulate temperature within environmental container14, a cooling fluid is provided via cooling fluid input18to environmental container14. A controller (shown inFIG. 2) monitors temperature within environmental container14and selectively controls a position of a valve (also shown inFIG. 2) to regulate the flow of the cooling fluid and therefore the temperature within environmental container14. In this way, the temperature within environmental container14is controlled to a desired value, providing, for example, a stable cold junction reference for use with thermocouple sensors. In addition, environmental container14may include other features, such as insulation, to mitigate drastic external temperature changes. Power input16provides power to circuitry included within environmental container14, such as a controller, a valve, and sensor conditioning circuitry (shown inFIG. 2).

In the embodiment shown inFIG. 1, station probe10is a wireless station probe including wireless antenna26for transmitting sensor information from station probe10to a control room or data collection center. In other embodiments, a wired communication terminal is provided for communicating sensor information from station probe10to a control room or data collection center via a wired communication protocol.

A benefit of station probe10is signal conditioning circuitry is connected to various temperature sensors and/or pressure inlets only once, during assembly of station probe10. Subsequently, station probe10may be installed on different engines without requiring each sensor to be individually disconnected/re-connected, only station probe10itself must be connected or disconnected from the engine being tested. In addition, station probe10does not require the presence of wires (i.e., thermocouple wires) and pressure lines extending from each sensor to a control room remotely located relative to station probe10. Rather, the sensor signals provided by the plurality of temperature and/or pressure sensors are analyzed locally by the signal conditioning circuitry within environmental container14and measured temperature/pressure values are communicated wirelessly or via a single wired connection to a control room.

FIG. 2is a block diagram of components included in environmental container14according to an embodiment of the present invention. Components include signal conditioning circuitry30, communication controller32, cooling fluid valve34, temperature controller36, and internal temperature sensor38. Inputs provided by temperature sensors20and from pressure sensor inlets22are provided to signal conditioning circuitry30. In response to sensor signals received from the various temperature/pressure sensors, signal conditioning circuitry30generates measured sensor values (i.e., converts the voltage and/or current signals provided by the sensors to values representing the measured temperature and/or pressure).

Temperature sensors20may be thermocouple devices that provide a current and/or voltage signal having a magnitude related to the measured temperature, resistive temperature devices (RTDs) that require signal conditioning circuitry30to provide a reference voltage and/or current that is modified by the RTD based on the measured temperature, or other well-known types of temperature sensor. Signal conditioning circuitry30monitors the voltage and/or current signals provided by temperature sensors20and in response generates measured temperature values for provision to communication controller32.

Likewise, signal conditioning circuitry30receives pressure inputs communicated via pressure lines from pressure sensor inlets22via pressure lines27and converted to analog signal by transducers28. In the embodiment shown inFIG. 2, a pressure transducer is employed to convert the pressure signal to an analog signal for processing by signal conditioning circuitry30, although in other embodiments other means may be employed to convert the pressure signal to an analog or electrical signal for processing by signal conditioning circuitry30. The measured pressure values are provided to communication controller32, which communicates the measured temperature and/or pressure signals either via wireless antenna26(also shown inFIG. 1) or wired connection via wired terminal40to a control room and or data collection center.

The internal temperature of environmental container14is regulated by controller36to maintain a desired temperature. Temperature controller36receives feedback from internal temperature sensor38regarding the temperature inside environmental container14. Temperature sensor38may be an independent temperature sensor, or may monitor voltage at a cold junction terminal associated with one or more of the thermocouple wires associated with temperature sensors20to measure the internal temperature of environmental container14. In response to the monitored internal temperature, temperature controller36modifies a position command to cooling fluid valve34to increase or decrease the flow of cooling fluid, and thereby regulate the temperature within environmental container14.

In this way, the station probe employs an environmental container to provide a stable temperature environment for housing sensor circuitry used to locally interpret temperature and/or pressure signals provided by sensors located on an attached rake portion of the station probe. This solution obviates the need for long wires and/or pressure lines to connect sensors to a remotely located control room.