Rockwell International Corporation

Sarkis Barkhoudarian

Rudolf R August

Jonathan M Maram

Optical measuring devises for measuring the angular position and rotation rate of a shaft 14. The shaft 14 has a variable pitch diffraction grating 22 etched on one end 16. The pitch gradient of the diffraction grating 22 varies as a function of circumferential position on the shaft 14. A monochromatic light source such as laser source 50 provides incident beam 20 which strikes grating 22. A diffracted light beam 26 from a the grating 22 strikes a position detector 61 at varying positions depending on the angular position of the shaft 14. By employing a position detector 61 which is sensitive to the position of the diffracted beam 26, a continuous position indicator of the shaft angular rotation is possible. A microprocessor calculates shaft position and rotation rates from the data supplied from the beam position detectors.

Diffraction grating rotary speed sensor having a circumferentially

A forced-excitation ultrasonic cavitation detection system for detecting cavities in rotating machinery such as pumps, water turbines and ducting elements, is composed of an ultrasonic transmitting transducer attached to the outer wall of the test component for transmitting ultrasonic pulses into the test component, and at least one, and preferably a plurality of ultrasonic receiving transducers attached to the outer wall of the test component for receiving the ultrasonic pulses passing through the test component. The ultrasonic transmitting transducer is excited by an ultrasonic pulse generator. An electronic data processing system is provided which is connected to the output of the receiving transducers and is also connected to the ultrasonic pulse generator through a synchronization line. The data processing system is programmed to discriminate as between signals from the receiving transducers due to cavitation in the test component, from other extraneous signals including noise. For this purpose the data processing system includes an algorithm, such as ensemble averaging, time-gating or cross-correlation, each capable of extracting signals due to cavitation from noise signals even of much higher intensity. When there is no cavitation, a maximum signal is received. In the presence of cavitation, as by the presence of vapor or gas bubbles, this interferes with the propagation of the pulses, thus reducing the amplitude of the received signal.

Ultrasonic cavitation detection system

A nonintrusive flow sensing system (10) and related method are provided for monitoring fluid flow within a conduit (14), particularly such as a liquid flow (12). The sensing system (10) includes an array of ultrasonic transducers (18, 20, 24, 26) mounted on the conduit (14) and adapted to send and receive pulsed ultrasonic signals bidirectionally across the conduit with an upstream-downstream component of direction, and through the conduit in longitudinal and circumferential directions. Signal transit times are processed to obtain accurate measurements of liquid flow velocity, temperature and pressure.

Nonintrusive flow sensing system

An improved leak detection system (10) of the differential absorption type is provided for identifying gas leaks in a test object (12), wherein the improved system (10) provides enhanced resolution and accuracy by compensating for the effects of background gases and the like along the image path. The system utilizes a video camera (18) to generate images of the test object (12) which has been pressurized with a selected gas (14) having strong absorption properties with respect to an illuminating light source (16) of a selected wavelength. Since the absorption bandwidth of the test gas (14) varies with temperature, the gas is preconditioned as by heating such that the temperature of gas leaking to the exterior of the test object (12) will vary with proximity to the test object. The camera (18) observes the pressurized test object in sequence through filters (30, 32) of narrow and broad bandwidth to generate a pair of images which can be electronically compared to isolate upon the test gas (14) located substantially at a specific leakage site or sites on the test object.

Leak detection system with background compensation

An optical pressure sensor 10 for measuring the pressure within a container 12 such as a combustion chamber of a rocket engine, wherein pressure sensor 10 comprises a pressure deflectable diaphragm 14 in communication with container 12 and which includes an optical grating 22 on one of its surfaces, means 18 for directing a laser 20 to strike optical grating 22 from a fixed direction to form a central diffracted beam 24 and a first order diffracted beam 26, a photo-position detector 60 for generating signals responsive to the changes in position of the central and first order diffracted beams 24 and 26 resulting from the effects of pressure and temperature upon the diaphragm 14, and means 30 for synthesizing a temperature-adjusted indication of the pressure in the subject container from said responsive signals.

Optical pressure sensor

A leak locating, mapping and measuring system (10) comprising an image recording medium (32), a laser (18), optical components (22) which cooperate with the laser to produce and superimpose successive holographic images of the test subject (12) upon the recording medium, a video camera (34) trained upon the medium and a real-time monitor (35) and recorder (36) for processing the output of the camera to assist analysis. The device is operated to create a first, reference hologram of the test subject while it is in an unpressurized state. A second holographic image is then taken while the test subject is pressurized with fluid from tank (38), which image is superimposed over the reference image. The resultant lines of interference between the superimposed images are then analyzed for distortions (66), which distortions indicate the location and magnitude of leakage flows at or about the test subject. Each holographic image may be created with laser beams of a selected duration which diminishes the effects of vibration in the test subject.

Leak locating and mapping system and method

A system for the examination of a test object for internal flaws (or acoustic discontinuities such as solid-to-gas or solid-to-liquid interfaces) by means of ultrasonic waves. The ultrasonic waves 18 are induced in the object 16 by projecting at least one intense, pulsed laser beam 13 on the object 16 and scanning the beam 18 along the object 16. Another laser beam 23 is projected on the object 16, either opposite the first beam 14 or on the same side adjacent to the first beam 14, so that is reacts with and is frequency-modulated by the ultrasonic wave. The reflected, frequency-modulated beam 24 is fed to an optical heterodyning means 26 which passes through only an optical beam 28 modulated with the ultrasonic frequency to a photodetector 30. A flaw 36 (or acoustic discontinuities such as solid-to-gas or solid-to-liquid interfaces) in the test object 16 results either in a decrease or an increase in the output of the photodetector 30, depending on whether the detection laser beam 23 is on the opposite or same side, respectively, of the test object 16 as the ultrasonic-wave-inducing laser beam 13. The system is characterized by non-contact with the test object by the ultrasonic-wave generation-and-detection means.

Contact-free ultrasonic transduction for flaw and acoustic discontinuity

An angular accelerometer utilizing a sensing element 10 comprising a strain member 18 and a crosswise torsion member 24, both substantially comprising flat beams 18 and 25, respectively. The strain member 18 is affixed at each end to the object whose angular acceleration is to be measured, the angular acceleration vector lying along the axis of the strain member 18. The torsion member 24 is formed with an end mass 26,26' at each end. The strain member 18 is formed from a material such as quartz whose elasticity changes in proportion to the torque it experiences. A high-frequency surface acoustic wave is sent along the strain member and the change in its frequency due to the torque in the strain member 18 is measured.

Surface-acoustic-wave, digitized angular accelerometer

A torquemeter 10 comprising a magnetostrictive element 12 which is formed in the shape of a ribbon upon the surface of the subject rotating member 14 and is capable of producing internal, avalanche Barkhausen reversals, permanent magnets 16 and 18 positioned adjacent to the subject rotating member 14 for successively triggering the avalanche Barkhausen reversals in the magnetostrictive element and for resetting the magnetostrictive element after each reversal, a pickup coil 20 for generating signals responsive to the avalanche Barkhausen reversals and a readout circuit 22 in communication with pickup coil 20 for correlating the responsive signals to an indication of the level of torque and/or power in the subject rotating member 14.

Lightweight torquemeter and torque-measuring method

A magnetic field is generated in the vicinity of a rotatably driven, loaded shaft. A Wiegand device in the shaft is differentially displaced by twisting of the shaft. Changes in magnetization in the regions during rotation of the shaft are detected by a coil. The characteristics of the pulses generated by the coil are representative of the twisting of the shaft and accordingly the torque transmitted thereby. A first signal is derived, which is representative of a characteristic of the generated pulses and a second signal is derived, which is representative of the period of the changes in magnetization. Power is represented by the quotient of the first signal divided by the second signal.

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Canoga Park, CA, United States of America

Sarkis Barkhoudarian