Abstract: An improved differential pressure transducer includes a chamber divided by a non-magnetic, electrically conductive measuring diaphragm supported between two support members each of which has a cavity covered with a seal diaphragm. Differential pressure of an incompressible fluid medium to be measured and transduced is applied to the measuring diaphragm, the displacement of which is detected by magnetic core detection coils. The detection coil magnetic cores are joined to the support members through spaces of magnetic material having temperature dependent characteristics opposite to that of the cores to thus neutralize temperatures induced effects.

Abstract: A graphic display device of the type which receives instructions from an external computer and, by successively scanning the rasters of a display matrix, displays patterns such as alphanumeric characters, symbols, etc. upon a cathode ray tube. The graphic display device has a pattern generator which stores patterns in raster form and generates signals for forming such patterns upon receipt of a pattern address signal designating the particular pattern to be formed, and a repeating raster designation signal designating the particular raster of stored pattern information to be accessed for each scan of the display matrix. Pursuant to the invention, the graphic display device comprises pattern shifting means for shifting, on demand and in an amount selected by the external computer, the display of a pattern in a direction transverse to the direction of raster scanning.

Abstract: An isolator circuit of the type designed to accept an input current and to generate a corresponding output current which is isolated from the input. The isolator circuit is formed with a core developing a flux in response to the input current and having a feedback winding for carrying the isolated output current. A magneto-sensitive element, such as a Hall effect element, responds to flux in the core, and an amplifier receives the output of the magneto-sensitive element and supplies a current to the feedback winding so as to cancel the flux produced in the core due to the input current. Improved frequency response is attained by means of a compensation winding disposed to respond to the difference between the flux produced by the input current and the flux produced by the output current.

Abstract: A signal transmission system of the type used in process control systems for conveying a signal between a field telemetering instrument and a central controller, or between a central controller and a process control device. The signal transmission system is arranged with a transmitter accepting an input signal, a transmission line for carrying a transmission signal, and a receiver receiving the transmission signal and developing an output signal.In accordance with the invention, converter means in the transmitter develop a pulse width signal with a duration corresponding in a predetermined manner to the value of the input signal, and means in the transmitter provide the transmission signal (e.g., a current signal) with two states (e.g., opposite polarities), one of which has a duration corresponding to the duration of the pulse width signal.

Abstract: A flow metering apparatus of the type having a vortex generating element with a generally elongate cylindrical shape placed in a stream of flowing fluid so as to produce Karman's vortices at a rate proportional to the velocity of the flowing fluid, with means for detecting the rate of production of vortices to give a linearly related measure of fluid velocity. To improve the correspondence of vortex production rate with flow velocity over wide conditions of flow, the element is formed with a rectangular cross-section in which the depth d along the direction of flow and the height h across the direction of flow are arranged in a ratio d/h of between about 0.5 and 0.9 and preferably in a ratio of 2/3. In the vortex generating element, passageway means extend between openings in the two opposed rectangle sides which are aligned with the direction of flow.

Abstract: A flow metering apparatus of the type having a vortex generating element with a generally elongate cylindrical shape placed in a stream of flowing fluid in a pipe so as to produce Karman's vortices at a rate proportional to the velocity of the flowing fluid, with ultrasonic means for detecting the rate of production of vortices to give a linearly related measure of fluid velocity. To improve the sensitivity of detection, especially at low velocities, the element is formed with a passageway transverse to the stream to produce therein an alternating fluid flow corresponding to the alternating shedding of vortices, and an ultrasonic generator and an ultrasonic receiver are positioned on opposite sides of the element so that the ultrasonic signal generated will be propagated through the passageway in the element and will be modulated by the alternating fluid flow therein.

Abstract: An apparatus for continuously measuring with safety and high accuracy the calorific power of a sample containing hydrocarbon compounds and sulfur, such as crude oil and petroleum products. The apparatus supplies two energy levels of radioactive rays to be absorbed by the sample, a first supply of the radioactive rays having an energy level at which the mass absorption coefficient of carbon differs from that of hydrogen, and a second supply of rays having an energy level at which the mass absorption coefficient of carbon is approximately equal to that of hydrogen. The first rays yield a signal varying with the concentrations of hydrogen, carbon and sulfur in the sample, while the second rays yield a signal varying with the concentration of sulfur in the sample. The signals are density compensated, and mathematically correlated according to a predetermined arithmetic formula to determine the calorific power of the sample hydrocarbon compound.