Abstract: An ultrasonic level measuring system is disclosed for determining by a time-ratioing technique the level of a liquid within a storage tank. An instrument sensor assembly, including a waveguide formed of a tensioned, ferromagnetic wire having a low thermoelastic coefficient is vertically supported within a storage tank containing a liquid. The waveguide is positioned to span both the tank liquid and vapor spaces. Two permanent magnets are positioned in close proximity to the waveguide at a known dimensional separation which defines the calibration span of the system. The waveguide and magnets are housed in a protective shield which acts as a process barrier and which is convoluted over a substantial portion of its length allowing the instrument sensor assembly to be easily transported and installed. A float, housing a permanent magnet, is positioned concentrically about the instrument sensor assembly to rise and fall with the liquid level.

Abstract: A receiver for a carrier that is swept in frequency in a predetermined manner over a bandwidth comprises frequency tracking with continuous self-synchronization. The frequency tracking permits the carrier to be filtered by a narrowband filter. The filtered carrier is then fed to a frequency discriminator to produce an error signal. A highly-selective phase-locked loop synchronizes only to the desired component of the error signal in frequency and in phase. The output of the phase-locked loop, after appropriate shaping, is the control signal for tracking synchronously the incoming wave. The output data are obtained at detection after the narrowband filtering.

Abstract: An industrial process control system to be used with processes which are geographically spread out over a relatively wide field area, with portions thereof located in respective zones, and wherein the process has associated therewith a large number of instrumentation elements including sensing elements and operating elements for controlling actuators such as process valves. The control system includes a central station with a digital computer which directs signals to a number of primary transmitter/receiver units each producing a swept-carrier wireless signal for transmission to a respective one of the field area zones. Within each zone are a plurality of local transmitter/receiver units similar to the primary units, with each local unit being assigned to one or more sensing elements and/or one or more operating elements.

Abstract: A pressure measuring instrument of the vibrating-wire type comprising an elongate base on which is pivotally mounted an elongate lever parallel to the base. A vibratory wire in the form of a very thin flat ribbon of tungsten is held tautly between the lever and the base. A pair of bellows are supported on the base, on opposite sides of the pivot mounted for the lever, and apply a torque to the lever proportional to differential pressure. Counterbalance means are provided to prevent errors with changes in spatial orientation of the instrument. The lever support-structure is formed of a composite of elements providing a match of temperature expansion characteristics with the vibratory wire. An overrange protection mechanism prevents the application of excessive force to the wire.

Abstract: An industrial process control system to be used with processes which are geographically spread out over a relatively wide field area, with portions thereof located in respective zones, and wherein the process has associated therewith a large number of instrumentation elements including sensing elements and operating elements for controlling actuators such as process valves. The control system includes a central station with a digital computer which directs signals to a number of primary transmitter/receiver units each producing a swept-carrier wireless signal for transmission to a respective one of the field area zones. Within each zone are a plurality of local transmitter/receiver units similar to the primary units, with each local unit being assigned to one or more sensing elements and/or one or more operating elements.

Abstract: A magnetic flowmeter includes a field coil extending along the longitudinal axis of a flow conduit for generating an integral magnetic field concentrically located about the coil and perpendicular to the flow. An inner electrode surrounds the coil, and the conduit itself is used as the other electrode, thereby providing a large surface-area electrode for sensing flow induced voltages. High current (over 20 amperes), very short duration (less than 10 millisecond) pulses energize the field coil whose inductance is low enough to permit electrode output voltages to be read within a few milliseconds after the magnetic field current pulse is turned on. The measured output voltage comprises a short-pulse, flow induced component proportional to flow rate, superimposed on a d-c voltage approximately equal to the galvanic potential at the electrodes.

Abstract: A diaphragm assembly for use in highly corrosive industrial applications includes a metal body subject to corrosion and a diaphragm formed of a corrosion resistant metal. The metal of the diaphragm is metallurgically incompatible with the body metal. The diaphragm is nevertheless hermetically sealed to the body with the aid of a transition member having a first portion of metal which is metallurgically compatible with the body and a second portion of another metal metallurgically compatible with the diaphragm. Both portions are joined together by a sound, molecular bond, as for example, by using explosive bonding techniques. The first portion of the transition member is fusion welded to the body and the diaphragm is similarly welded to the second portion, thereby presenting at the process fluid interface a barrier that consists solely of corrosion resistant metal.

Abstract: A method and apparatus for protecting the transducer in a liquid-filled differential pressure transmitter having stroke limited, isolation diaphragms from exposure to overrange pressure are disclosed. Bidirectional overrange pressure protection is provided through the use of a single, preloaded bellows that is restrained by a preloaded stop means preferably including a preloaded mechanical spring. The bellows remains stationary when the differential pressure transmitter is exposed to a normal, operational differential pressure. When an overrange pressure is applied to the transmitter, the bellows expands or contracts to accommodate the liquid displaced by either of the isolation diaphragms thereby protecting the transducer from the overrange pressure. Upon removal of the overrange pressure condition, the protection apparatus automatically resets itself.

Abstract: Signal-processing apparatus for use with industrial instrumentation systems and the like, and comprising memory means to maintain a signal level for long time periods without drift. An input signal level is translated into the positioning of a movable member, through the use of an actuator motor controlled by the input signal and a position feedback signal. A friction device is coupled to the movable member to hold it in any given position, thereby to serve as a memory for the input signal level. The friction device comprises a thin vane-like element which is secured to the movable member and disposed in the air-gap of a permanent magnet. The air-gap also includes a mass of tiny magnetizable particles which, under the influence of the magnetic field, engage the surfaces of the vane-like element to develop a frictional restraining force.

Abstract: A force-measuring instrument of the vibrating-wire type wherein the mechanical components are located at the force-measuring location and the vibrating wire is coupled through a two-wire transmission line to electronic circuitry at a distant location. The electronic circuitry includes means to excite the vibrating wire and to produce a d-c measurement output signal corresponding to the frequency of vibrations. The electronic circuitry further includes function-generating means to establish a closely-linear relationship between the output current and the force applied to the wire. Means also are incorporated in the electronic circuitry for adjusting the zero and span of the instrument, and this can be done without interaction between the adjustments.

Abstract: A process chromatograph including a column for separating fluid samples into their individual components, and a density-responsive detector connected to the column output to produce a pressure signal representing the concentration of the separated components. The column and associated elements are contained within a thermally-insulated housing the interior spaces of which are heated and maintained at a set-point temperature by a temperature regulating system. Heat energy is supplied by steam to one section of a two-section tubular heat-exchanger. A stream of air is caused to flow through the other section and into the housing interior, to transfer heat thereto. The rate of heat transfer is automatically controlled by a thermostatic control which continuously adjusts the flow of air through the heat exchanger so as to maintain the interior temperature at a desired set-point.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: At least one of two wing-like elements that extend longitudinally alongside each other in the stream of a flowing fluid is pivotally mounted so as to oscillate at a frequency proportional to fluid flow rate. These elements, after being properly positioned with respect to each other, are readily inserted in large conduits to provide accurate measurement of line average flow rate over a wide range of values.

Abstract: A vortex flowmeter in which the vortex-shedder and the vortex sensor comprise two distinct, easily separable assemblies that may be readily removed and/or assembled from the interior of a flow conduit. The sensor is housed in a body fixedly suspended within the conduit by an integrally connected support structure extending outwardly through an opening in the conduit wall. The shedder comprises a blunt front face extending across the interior of the conduit for producing vortices and a bar-member joined to the front face and extending downstream therefrom defining an area for detecting the vortices. The bar-member is formed with a lateral recess that matches the pattern of the sensor and support structure such that when the shedder is positioned to engage the sensor, the overall bar-member configuration is preserved to assure good measurement results. Outside of the conduit, the support structure is securely fastened to the conduit so as to firmly hold the sensor within the shaped recess.

Abstract: A vortex-shedding flow-sensing instrument comprising a flat-faced vortex-generating plate integral with a downstream sensor-bar having flat sides set back laterally with respect to the rows of vortices shed from the edges of the vortex-generating plate. The side surfaces of the plate are tapered inwardly at a moderate angle, and extend downstream a short distance to rear surfaces at right angles with respect to the direction of fluid flow. The downstream end of the sensor bar comprises a tail piece the side surfaces of which are tapered inwardly at a moderate angle, and extend downstream a short distance to a rear surface perpendicular to the direction of fluid flow.The sensor bar carries a liquid-filled capsule having as side walls a pair of flexible diaphragms effectively in the plane of the sensor-bar side surfaces. These diaphragms are of moderately large area so as to respond to a relatively large portion of the vortex energy.

Abstract: An all-pneumatic process chromatograph having a pneumatically-actuated sample-injection valve, an orifice connected in the column output line to develop a pressure signal corresponding to fluid density, a pneumatic amplifier for strengthening the pressure signal, and pneumatically-operated control means for developing a periodic sample-valve actuating signal and for selecting a particular peak of interest at a controllable time following injection of the sample. The pneumatic control means includes means automatically operable to adjust the time of peak selection in response to changes in actual peak elution time. The temperature-sensitive elements of the apparatus are contained in a chamber which is heated by a source of steam heat, with the rate of heat transfer being regulated pneumatically to maintain a relatively constant temperature within the chamber.

Abstract: An amperometric analysis system and method includes a flow tube constituting the amperometric cell in which magnetic flow metering electrodes function also as the counter and test electrodes for amperometric measurement. By combining the magnetic flow measurement with the amperometric measurement, additional electrodes are not needed to obtain the flow signal for compensating the amperometric measurement. Ultrasonic drivers are mounted on the end of the shank of the counter and test electrodes and driven by an ultrasonic oscillator to activate the electrodes to keep them clean. Complementary cleaning can be obtained through the simultaneous application of an electrochemical anodic pulse. The system includes a three-electrode circuit potentiostat in which the potential of the test electrode is fixed versus a reference electrode and the current flows between the test electrode and the counter electrode.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: A method and apparatus for controlling the operation of a distillation column which utilizes cost factors to achieve the best economical production of a product within acceptable purity limits while maintaining the column at maximum operating capacity. The control is based on a series of priorities in which each of the following control signals is selectively used in turn to modify the control the heat-input to the column; cost factors applying to the column, cost factors applying to the several columns in the system, the purity of the product, the operating pressure limit of the column and, for lighter products, the rate of fluid velocity through the column. For heavier products, the rate of fluid velocity through the column is used independently of the heat-input control to restrict the flow of overhead product to the condenser to increase the back pressure on the column.

Abstract: An electronic process control system including a digital computer, a computer interface that is easily replaceable in order to change computer types; a logic module for grouping the computer and controller signals and converting between digital and analog representations; and a control unit interface for generating analog signals for a control unit in response to computer commands and adapting the analog control unit to communicate with a digital computer.