Abstract: A system for improving the pulse-echo type of testing to determine certain parameters of tubes, such as internal diameter, external diameter, wall thickness, etc. A pair of pulses are directed transversely to the tube wall so that the transit times of the respective pulses and their reflections from a tube surface, are substantially different. From the value of the transit times associated with each pulse pair the respective parameter is derived. Inaccuracies due to undesired oscillations of the driving shaft for rotating the pulse transducer within the tube to be tested are eliminated. By means of auxiliary reflective surfaces each pair of pulses emitted from the transducer are directed transversely relative to the respective tube wall in substantially one and the same plane.

Abstract: A gas sensing apparatus is adapted to detect the presence of a gas of interest in air in very small quantities and to provide a rapid alarm or other indication in response to the presence of such gas. The apparatus incorporates a gas sensing composition which changes its electrical resistance more dramatically than previously possible in response to the presence of the gas and electronic circuitry designed to sense and evaluate the patterns of resistance change during the first approximately 30 seconds after exposure to gas and to accurately estimate gas concentration based on such initial resistance variations. The system also looks at overall change in sensor resistance to detect gradually increasing gas levels. A preferred method of manufacturing the sensor and a sensor configuration particularly suited to the early detection of gas levels are disclosed.

Abstract: Method and apparatus for diagnosing abnormality of an oil-filled electric apparatus is disclosed. Presence or absence of abnormality is determined by comparing contents of plural predetermined components contained in gas extracted from the oil of the electric apparatus with respective predetermined reference values. The type of abnormality is determined on the basis of at least one set of two specific components selected from the plural components.

Abstract: A counterflow helium mass spectrometer leak detector includes a test port for receiving a gas sample including the tracer gas helium, a high vacuum pump such as a diffusion pump and a mass spectrometer tuned to detect the helium. The mass spectrometer is coupled to the inlet of the high vacuum pump. The leak detector further includes a cold trap containing liquid nitrogen coupled between the test port and the foreline, or outlet port, of the high vacuum pump. The helium received at the test port passes in reverse, or counterflow, direction through the high vacuum pump to the mass spectrometer. One or more mechanical vacuum pumps insure that the pressure at the foreline of the high vacuum pump is maintained at a prescribed level during a leak test. The cold trap condenses contaminants, water vapor and other gases from the gas sample and prevents backstreaming of oil from mechanical vacuum pumps.

Abstract: A procedure and an apparatus for continuously measuring the coal content of quick ash, ash being fed through a measuring chamber (1), through between measuring capacitor plates (2), the change of capacitance caused by the coal being measured, and a measuring signal being formed which characterizes the coal content of the ash.

Abstract: A gas detecting and monitoring device comprises a bridge circuit including a gas detecting element and a constant-current circuit for feeding a constant current to the gas detecting element. The device further comprises a compensating bridge circuit including at least a part of the gas detecting element. The compensating bridge circuit produces a signal corresponding to the variation of the resistance value of the gas detecting element depending upon the variation of the ambient temperature and feeds the signal to the constant-current circuit to automatically control the current fed to the bridge circuit thereby maintaining the resistance value of the gas detecting element at a constant value. The device may further comprise a correcting circuit including a temperature sensor for sensing the variation of the ambient temperature disposed near the gas detecting element.

Abstract: Two axis shaker vibration of a slip plate is achieved by use of angularly disposed shakers of novel design, each being provided with an armature cantilevered from the slip plate and free to laterally translate at the same time they drive the slip plate. Pivoting moments are converted to linear motion by a torsionally stiff flexure support for the slip plate.

Abstract: A circuit for adjusting the sweep time provided by a sweep generator used in an ultrasonic test instrument is described. The adjustment takes into account three test parameters, i.e. the angle of propagation of the sound in the workpiece, the speed of propagation of sound in the workpiece, and the thickness of the workpiece. To this end, the quartz-stabilized frequency of an oscillator comprising an adjustable frequency divider is divided by the angle function value of the angle of sound propagation to which the test instrument is set. The divided frequency is fed to a frequency multiplier in a phase locked loop circuit, comprising an adjustable frequency divider by means of which the speed of propagation of the sound is adjusted. A succeeding time reference stage contains also an adjustable frequency divider by means of which the workpiece thickness is adjusted.

Abstract: This invention is concerned with a method and apparatus for measuring the electro-kinetic properties of a liquid which may be a mixture such as a slurry of particles, or a dispersion of droplets. Electrodes are placed in the liquid and an apparatus is provided for applying an alternating electrical potential to these electrodes. The electric field from this alternating potential acts upon the charged elements in the liquid, resulting in the generation of sound at the frequency of the applied electrical potential. By placing a conventional acoustic transducer in a spaced relationship to the electrodes, the acoustic signal is detected and measured. The amplitude of the acoustical signal will be a function of the electro-kinetic properties of the particles or emulsion droplets in the liquid. In its preferred form, the electrodes that are placed in the liquid have a spacial separation of one-half wave length, or odd integer multiples of half wave length of the sound which they generate.

Abstract: According to the process signals adapted to the medium and to the kind of discontinuity to be analyzed are transmitted towards the discontinuity from a number of transmitting points located on at lease one base line, these signals are received at a number of reception points located on at least one base line placed on the opposite side of the discontinuity as far as the transmission paths are concerned; the received signals are then analyzed to obtain the position and shape of the discontinuity. In certain cases the echos and backscatter are also analyzed. At least one of the base lines F.sub.1 carrying the transmission points does not intersect with at least one of the other base lines carrying the reception points. This system and method may be used to determine the position and shape of underground discontinuities, to analyze the internal structure of human or animal bodies, or any other inanimate object in any medium.

Abstract: A collapsible parachute is propelled through a pipeline by flow of the pipeline contents. The parachute tows a pipeline profiling device which may include spring loaded feeler arms. The parachute collapses in order to pass obstructions or constrictions in the pipeline, and the feeler arms of the profiling device retract to avoid becoming stuck in the pipeline.

Abstract: A sensing device which senses the presence and/or concentration of one or more gases contained in a mixture is disclosed. An electrically charged semiconductor whose surface is in contact with the mixture of gases is illuminated with light, either intermittently or constantly. Changes in the transient and steady state conductivity of the semiconductor are measured and amplified. The form of the functionality between the gas and the conductivity changes is unique to a particular gas at a particular concentration and is used both to detect the presence and/or concentration of the gas.

Abstract: A pressure gauge for determining the pressure applied to a cylindrical vibrator by measuring the resonance frequency of the vibrator. The vibrator comprises a thin-wall cylindrical portion, a thick wall cylindrical portion extending from one end of the thin wall cylindrical portion and a thick wall end portion joined to the end of the thin wall cylindrical portion. The thin wall cylindrical portion is installed within a cover, to which the thick wall end portion is securely attached. The inventive vibrator type pressure gauge produces greater accuracy and reliability while also being resistant to external vibrations and pressures.

Abstract: An arrangement is provided for the simplified and rapid recalibration of electrochemical toxic gas detectors. Periodically, a single untrained operator may temporarily operate the system of the invention for adjusting the "span" and "zero" settings on the sensor, make two adjustments until he obtains a signal, such as a light signal, in order to obtain recalibration. The arrangement allows the use of untrained personnel to make otherwise technical adjustments in remote regions where gas detectors may be utilized. The system of the invention may be located at the sensing head of the toxic gas sensor or at the controller thereof.

Abstract: A filter testing apparatus and method are provided wherein a challenge aerosol or the like is introduced upstream of the filter, and the downstream face of the filter is scanned with an air sampling probe to detect for the presence of leaking aerosol. The apparatus comprises a generally rectangular frame, and an air sampling probe which is mounted to the frame so as to be movable in a predetermined pattern wherein the entire face of an adjacent filter is scanned. The assembly may be removably mounted in a filter housing immediately downstream of the filter, or mounted on a framework downstream of a bank of several filters. In the latter instance, the assembly is sequentially indexed to a position alignment with each filter, and an upstream aerosol dispersion assembly is also provided which is correspondingly indexed across the filter bank.

Abstract: A process and apparatus are provided for continuously sampling, for example, crude oil, to determine the amount of water and bottom sediments in the crude oil, wherein the crude oil is passed through a mixing zone in a pipeline to homogenize the crude oil, a fluid stream is continuously withdrawn from the homogenized crude oil and introduced into a collecting vessel. The collected fluid is mixed for homogenization, whereafter a sample is taken from the fluid for analysis.

Abstract: Tracer emission sources which emit tracer gas at a predetermined constant known rate are distributed throughout a building. The preferred source is a small vessel containing a vaporous perfluorocarbon tracer (PFT) substance having a very small bore hole in the top through which the PFT vapor can escape. Time is permitted for the tracer gas to mix uniformly throughout the building and for its concentration to equilibrate with infiltrating air. The concentration of the tracer is then measured and compared to the known volume of air in the building to determine the infiltration rate. In the preferred mode, the concentration is integrated and measured by continuously sampling the tracer gas at a constant rate on activated charcoal adsorbent over a period of several weeks.

Abstract: An ultrasound imaging system is provided having an articulated arm for holding a transducer. Signals representative of the angular position of the arm joints are scaled up to a voltage range over which the restricted range of movement of each joint is distributed. The scaled signals are combined to produce a plurality of combined angular signals, which then may be digitized and used to compute the X-Y position of the transducer.

Abstract: A noble gas leak detector is provided using a non-evaporable getter pump to remove active gases but not noble gases during leak detection. The vacuum system is constructed of all-metal valves, metal connection devices and metal passageways to reduce out gassing and minimize the permeation of helium into the system. Valves are appropriately located to seal off unnecessary devices during the actual leak detection. In addition, a process of calibrating a noble gas leak detector is provided using americium 241 alpha as the calibrating source.

Abstract: Apparatus for the optical observation of the evolution of instabilities between two fluids having different densities subject to high initial pressures, of the type comprising an observation chamber with parallel faces containing the two fluids, initially separated by a diaphragm, and wherein it comprises in combination the arrangement of the observation chamber within a tight enclosure equipped with static pressurizing means and whereof one face is constituted by an optical observation window parallel to the two parallel faces of the observation chamber, the diaphragm having a straight cylindrical shape and is coupled to a mechanical extraction shaft, the geometrical axes of the diaphragm and the extraction shaft being perpendicular to the faces of the observation chamber, the extraction shaft sealingly sliding through the wall of the enclosure opposite to the said window, while part of the extraction shaft external of the pressure enclosure is integral respectively with a piston sliding within a cylinder an