Abstract:
An ultrasonic cleaning apparatus and method is provided for a venturi flow nozzle which is mounted in a pipe having fluid flowing therethrough. The apparatus includes a plurality of ultrasonic transducers mounted in openings provided upstream of the venturi flow nozzle inlet. The transducers transmit ultrasonic waves directly into and thereby excite the fluid flowing through the venturi flow nozzle and create cavitation which cleans the nozzle. Additional transducers are preferably provided in the throat area of the venturi flow nozzle. In alternative embodiments, the transducers are mounted in high and low pressure taps associated with the venturi flow nozzle such that the transducers directly transmit ultrasonic waves into fluid flowing into the high and low pressure taps. The transducers may be mounted flush with the interior of the pipe or venturi flow nozzle, or the transducers may be mounted at a position spaced therefrom in the high and low pressure tap piping.
Abstract:
A method and apparatus which indicates an actual arc occurrence only if a voltage or current of a generator neutral lead exceeds a specified threshold amplitude, and is followed by a second RF signal again exceeding the threshold amplitude and occurring within a specified time period.
Abstract:
A system for monitoring the temperature of a plurality of turbine blade shroud segments includes indicia carried by each shroud segment. A sensor produces input signals in response to the indicia. A temperature sensor measures the temperature of the sensor producing the input signals. A first circuit, responsive to the temperature sensor, corrects the input signals to compensate for the effects of temperature on the sensor. A second circuit determines the temperature of each shroud segment based on the corrected input signals.
Abstract:
A flow sensor includes a strap-on heater attached to a fluid conduit downstream of a drain valve and two differential temperature measuring thermocouples attached to the fluid conduit downstream of the heater. A monitoring system employing at least one of the flow sensors further includes a controller which receives the differential temperature signal produced by the two thermocouples, a signal indicative of a selected valve position, and a signal indicative of steam turbine operating condition, i.e., hot or cold. The controller includes a logic circuit for correlating the differential temperature value signal, the valve position signal and the steam turbine condition signal to a diagnosis of the drain valve condition.
Abstract:
An improved tracer gas leak detection system and method for air inleakage testing of a turbine-condenser system quantified leak testing with two new elements: one, by providing discharge of a fixed, reproducible amount of tracer gas at a possible leak site, which is accomplished by controlling the flow rate, pressure and time interval of the discharge. Secondly, the total amount of tracer gas subsequently detected within the turbine-condenser is determined by integrating the detector response.
Abstract:
A heated, split thermowell comprises a cylindrical shank and integral, axially extending, part-cylindrical probes spaced by at least a first gap defined by a bilateral plane. The thermowell is mounted to the sidewall of a pressure vessel for communicating through a penetration in the sidewall with the fluid state in the pressure vessel. Each probe has at least one parallel axial bore therein, a related, selected pair of probes receiving respective heater and temperature sensing elements in the associated bores, and together functioning as a differential temperature sensor producing distinguishable, differential temperature outputs representative of the fluid condition of steam versus water. Duplex sensor embodiments permit toggling between different, selected such pairs of probes for on-line testing and verification of monitored conditions and operability of the elements and supporting circuits, with automatic substitution of complementary elements in the event of element failure. Each thermowell also permits on-line replacement of a failed element.
Abstract:
A thermally self-adjusting mount for a proximity sensor for detecting movement of a turbine blade tip within a turbine housing includes an elongated chamber in an interior wall of the turbine housing adjacent the path of travel of the turbine blade tip. The chamber is configured to receive a blade tip sensor therein and accommodate relative movement of the sensor toward and away from the path of travel of the blade tip. A thermally expansive element is operable coupled with the sensor for moving the latter in the chamber toward the path of travel of the blade tip upon heating of the sensor. A spring is provided for maintaining the sensor in contact with the thermally expansive element during both expansion and contraction of the latter. The thermally expansive member is capable, upon being heated to any given temperature, of causing movement of the sensor in the chamber and relatively toward the path of travel of the blade tip a distance which is substantially the same as the linear movement of the wall away from the path of travel due to having been heated to the same temperature. Thus, the spatial relationship between the sensor and the path of travel of the blade tip remains the same at different temperatures.
Abstract:
A method is disclosed for eliminating aberrations in position-time data provided by an apparatus which monitors the position of a rotating blade in a turbo machine as a function periodic rotation, the apparatus including at least one sensor adjacent at least one blade position to provide a time signal corresponding to the actual arrival time required for a blade to move from a predetermined position to the at least one sensor position, the aberrations being caused by misalignment or movement of the at least one sensor with respect to a rotating blade. The method comprises the steps of first calculating an average blade arrival time for blade movement from the predetermined position to the at least one sensor position, and then estimating sensor position relative to the predetermined position based on blade velocity and average arrival time. Alternatively, measured displacements between blade position and sensor position at the average blade arrival time may be used to derive a time signal indicative of blade vibration.
Abstract:
A liquid-filled tube placed next to a generator winding section provides an indication of an abnormal hot spot which may develop along the winding. The tube is filled with a liquid which vaporizes to form a vapor bubble at the hot spot location. Acoustic energy is projected through the liquid in the tube and is normally received at the distal end of the tube. Presence of a vapor bubble blocks the acoustic propagation and forms a reflective surface for the acoustic energy which then is utilized to calculate distance to the vapor bubble. With a known pressure versus temperature relationship, the pressure of the liquid is controlled such that the hot spot temperature may be determined.
Abstract:
A generator stator core through-bolt tensioning device that automatically tightens the nut on the through-bolts that hold together and compress laminate plates of the stator core in a high voltage generator. A controller receives a signal from a measuring device, such as a fiber Bragg grating that measures the strain on the bolt, and based on that signal determines whether the nut needs to be tightened. If the controller determines that tightening is necessary, it will cause the tensioning device to automatically tighten the nut while the generator is in service, and use the measuring device to provide feedback of the tensioning of the through-bolt to know when to stop the device from tightening the nut.