Abstract: An ultrasonic sensor includes an ultrasonic transmitter, an ultrasonic receiver and a support structure. First and second elongated tubes are mechanically coupled to and extend from the support structure. A first elongated waveguide is operably coupled to the ultrasonic transmitter and extends through the support structure and a bore in the first tube. The first waveguide is acoustically isolated from the support structure and first tube except at a distal portion of the first waveguide. A second elongated waveguide is operably coupled to the ultrasonic receiver and extends through the support structure and a bore in the second tube. The second waveguide is acoustically isolated from the support structure and the second tube except at a distal portion of the second waveguide. A measurement gap is located between the distal portions of the first and second waveguides.

Abstract: A capacitive level sensor for sensing level of a in a vessel includes a sensor coupled to the vessel having a shield and an inner sensing rod. An oscillator provides an RF signal to the shield and the sensing rod. Comparison circuitry couples to the sensing rod provides a wet/dry output in response to capacitance between the inner sensing rod and the vessel, the capacitance related to the level of the liquid in the vessel.

Abstract: An ultrasonic level instrument detects the presence of a fluid at a defined location and provides a self-diagnostic integrity check. An excitation circuit simultaneously induces vibrations at a first and second frequency in a transmitting piezoelectric crystal, and the vibrations are detected by a receiving crystal. A first and second filter circuit generate first and second filter outputs, respectively, by selectively passing the receiving crystal output at the first and second frequencies, respectively. The first filter output is indicative of the presence of fluid and the second filter output is indicative of the sensor integrity.

Abstract: An ultrasonic transducer for measuring a property of a material within a defined space has a function of a velocity at which ultrasonic signals travel through the defined space includes a controller. The controller is adapted for coupling to a plurality of ultrasonic transducers. The controller include a multiplexer for selecting one of the plurality of ultrasonic transducers, signal processing means for processing an output of the selected ultrasonic transducer and controller means for providing parameters to the signal processing means based upon the selected ultrasonic transducer. The controller couples to a two wire 4-20 mA communication loop. The controller periodically excites the ultrasonic transducer to obtain a measurement. The controller stores power received from the two wire communication loop and excites the transducer using stored power. The controller is capable of providing power which exceeds that available directly from the two wire communication loop for a brief period of time.

Abstract: An ultrasonic liquid level sensor includes an ultrasonic coupling element for use in self testing. The sensor includes a gap and a pair of transducers spaced apart by the gap. The sensor senses presence of liquid in the gap. The ultrasonic coupling element extends between the transducers and acoustically couples them together. The coupling element is used to test ultrasonic sensor integrity.

Abstract: A process measurement system that utilizes fast neutron backscattering for measuring density, level, and interfaces of substantially non-hydrogenous materials. The present invention substantially expands the use of backscattering technology, by expanding measurement to materials other than those containing hydrogen, and allowing measurement of materials in thicker walled vessels than previously possible. The system contains a fast neutron source for emitting neutrons into the material to be measured. The detection system is mounted near the neutron source to receive the backscattered neutrons. An energy degradation system is also incorporated to reduce the energy level of the fast neutrons down to a desired range.

Abstract: A meter measures the quality of steam flowing in a conduit. The steam comprises a liquid and a vapor. The meter includes a mixer in the conduit for mixing the steam in the conduit to produce a mixture which has a density representative of the liquid and the vapor. A density sensor, or desitometer, senses the density of the mixture. The densitomer produces an improved output due to the mixing. A pressure sensor senses pressure in the steam line. A calculating means, such as a microprocessor system, calculates the steam quality as a function of the sensed density and pressure.