Abstract: A sensor for use in a vortex flow meter capable of measuring various physical characteristics of a flow in a single process penetration from a common source. A shedder bar in the vortex meter generates alternating vortices. The sensor, which is fluidly connected to the vortex meter, comprises one or more pressure and temperature sensing diaphragms containing piezoresistor elements arranged in a Wheatstone bridge configuration. The sensor produces electric signals indicative of flow velocity, fluid pressure, and temperature. These signals are transmitted to a processing element which computes additional flow parameters.

Abstract: A method and apparatus for identifying an unknown gas by generating an infrared spectrum of the unknown gas using an infrared spectrophotometer that includes a circular variable interference filter, compressing the infrared spectrum of the unknown gas, and comparing the compressed infrared spectrum of the unknown gas to a library of compressed infrared spectra of reference compounds. After comparison, the compressed spectra that most closely match the unknown gas are decompressed and displayed. Because frequency characteristics of circular variable interference filters vary from filter to filter, information designating these frequency characteristics for the particular filter employed are used in generating the infrared spectrum of the unknown gas.

Abstract: An overpressure-protected, differential pressure sensor 37 is formed by depositing diaphragm material 24 over a cavity 23 formed and filled with sacrificial material 22 into a front surface of a substrate. The sacrificial material 22 is then removed to create a free diaphragm. The floor of the cavity 23 defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port 33 is created to allow pressure to be applied to the bottom side of the diaphragm 24. An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap 35 to standoffs 34 placed around the top of the diaphragm. The standoffs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A modular pressure sensor has a pressure-sensing element, electrical terminals, interconnections, and a support substrate. The pressure-sensing element produces an electrical signal indicative of pressure at local contacts and the interconnections apply the signal to the electrical terminals. The electrical terminals are secured to the substrate and extend along a peripheral surface of the substrate. The modular pressure sensor can mount, with different orientations, to a header to form a pressure transducer.

Abstract: A level of a chemical in a fluid is accurately measured by an analyzer having an electrode assembly separated from the fluid by a membrane. The electrode assembly is energized to provide a steady state signal and a pulsed signal, both of which indicate the level of chemical in the fluid, but with only the pulsed signal being substantially unaffected by fouling of the membrane. The pulsed signal and the steady state signal are used to determine a predicted value that the steady state signal will have in the absence of fouling. The predicted value is then used to correct the steady state current to compensate for fouling of the membrane.

Abstract: In general, the invention features method for regulating sulfur dioxide emissions from the recovery furnace of a Kraft paper mill.

Abstract: A self-tuning deadtime controller for adaptively adjusting one or several controller parameters during process control activities. The controller tunes, for example, the controller deadtime and the proportional band to optimize deadtime controller performance. The high performance of a deadtime controller is maintained even though the controller is incorrectly pretuned or if the process is subject to loads which change its characteristics.

Abstract: A pressure sensor sub-assembly (18) has a solid-state sensing element (22) mounted on a laminated ceramic substrate (20) and has the electrical signal contacts (22a) on the sensing element electrically connected to connector pins (24) on the substrate. A manufacturing process can fabricate a batch of sub-assemblies on a substrate structure that is sub-divided to form the separate sub-assemblies. The sensor sub-assemblies can be tested, and graded, before or after the sub-division step, and then each mounted in a housing.

Abstract: Apparatus and method for adapting the control parameters of a self-tuning controller. The apparatus detects a closed-loop response to a naturally occurring, unmeasured disturbance and determines two characteristics, the attenuation and the period of the response. The attenuation and the period provide sufficient information to partially identify the characteristic equation of the closed-loop system. The apparatus constructs from the partially identified characteristic equation a process model that represents the general behavior of the process. The apparatus generates new control parameters more appropriate for the identified process model, and appropriately updates the controller.

Abstract: Radiant energy is transmitted to a probe element including an interior conical reflecting surface and a fluid sample chamber. Portions of the light which have been transmitted, partially attenuated, or scattered by a fluid sample in the sample chamber are directed by at least a portion of the interior conical reflecting surface to means for collecting the transmitted, partially attenuated, or scattered light. A stilling valve incorporated into the probe element enables elimination of entrained gas bubbles from the chamber.

Abstract: An electromagnetic flowmeter with conventional orthogonal electrode and magnetic axes (x, y) intersecting the flowtube axis (z) has its electrodes constituted by two pairs (1, 2 and 3, 4) of electrodes mounted in insulating tubing (5) on each side of the flow passage through the tubing. Four conductors extend respectively from the four electrodes to enable the potential difference between the two electrodes on each side due to an axial component on each side of eddy current electric field in the liquid to be determined for self-calibration purposes in compensating automatically for any extraneous change in the magnetic field and the average potential of each pair of electrodes can also be determined to derive the velocity of flow of the liquid. One of the two pairs of electrodes can be replaced by a single electrode.

Abstract: An apparatus and method for process control that extracts information from a process for developing a model of the process that is used to design system control. The apparatus includes means for selecting a process model form that has two or more selectable parameters. The apparatus also includes means for deliberately disturbing a process that is in open-loop operation and that is in a substantially settled state and further includes means for measuring the process response. The apparatus selects parameters for the process model form according to a function of the measured process response. In this way a complete model of the process is identified. The apparatus self-tunes by directly calculating new control parameters according to a function of the identified open-loop process model and a preselected target behavior.

Abstract: A local area network having fault detection and recovery and a method for detecting and recovering from faults in a local area network are disclosed. The network has modules interconnected by a token bus implemented by a pair of redundant cable systems. All of the modules are agent modules and one of the modules also serves as a master module. Each agent module periodically transmits an agent heartbeat signal on each of its cables. Each module monitors all of the agent heartbeat signals from all of the other modules. When a fault is detected by a module, such as missed agent heartbeat signals from another module, the module applies agent rules to determine if and how the fault should be reported. The agent module reports the fault to the master module. The master module collects fault reports from the agent modules, applies a set of master rules to the agent fault reports, and generates a master failure report.

Abstract: A method for patterning a tape to which an integrated circuit may be bonded including providing a tape having a top layer of unexposed film which, when exposed in an interconnection pattern and developed, acts as a mask for processing a photoprocessable layer of the tape to provide conductive portions in an interconnection pattern on the tape.

Abstract: A computer controlled equipment controller and method of operating the same for controlling industrial process control equipment which uses a language structure and data structure specifically adapted for use in constructing computer programs for controlling chemical and physical processing. A translator converts to compilable code programs written as statements expressing control intentions or results. Provision is made for treating the program structure (i.e., control connections, program order, and components, etc.) as part of the dynamic state of the application. Graphical symbols, or icons, are employed to draw the eye to critical features in the control program and to lead the eye through critical interrelationships among the several commands of a control system. At the same time, the translator treats the keystrokes generating these icons as statements (i.e.

Abstract: An overpressure-protected, differential pressure sensor (37) is formed by depositing diaphragm material (24) over a cavity (23) formed and filled with sacrificial material (22) into a front surface of a substrate. The sacrificial material (22) is then removed to create a free diaphragm. The floor of the cavity (23) defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port (33) is created to allow pressure to be applied to the bottom side of the diaphragm (24). An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap (35) to stand-offs (34) placed around the top of the diaphragm. The stand-offs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A microporous, photoprocessable, moderately hydrophilic material on which metal can be deposited directly using electroless plating techniques, and its use in preparing printed wiring boards and circuit components.

Abstract: A rigid central manifold block defines a coaxial inlet and outlet of the flowmeter and supports at least one continuous conduit loop substantially encircling the block and having its inlet and outlet ends closely spaced and rigidly connected to the block. Preferably, the loop includes a straight section perpendicular to the inlet and outlet ends. Dual drive means are preferably provided for oscillating the straight section back and forth about its perpendicular bisector and complementary position detectors employed at or near the opposite ends of the straight section, preferably at the same location as the drive units, provide readouts which are combined algebraically and synchronously demodulated to yield a Coriolis-related output indicative of mass flow. Preferably, a second loop, identical and parallel to the first, is supported by the same block. The block is channeled to serve as a manifold and interchangeable manifolds are disclosed for series and parallel flow through the two loops, respectively.

Abstract: A chromatography device for separating sample fluids from carrier fluids and analyzing the sample is configured so that it is a modular unit. This modularity enables repairs to be quickly effected on the unit and also greatly simplifies the task of accessing the components of the chromatography cartridge. The modular chromatography cartridge is comprised of separation columns for separating the sample fluid from the carrier fluid. The cartridge additionally includes detectors for detecting distinguishing characteristics of fluids exiting the column. Further, the cartridge preferably includes valve assemblies for directing the flow of the carrier fluid and sample fluid throughout the cartridge and restrictors for adjusting the flow rate of the fluids as they flow through the cartridge. All of the components of the cartridge are configured upon a manifold. The manifold has a means for attaching the cartridge to fluid sources and support structure. The manifold enables the system to exhibit its modularity.

Abstract: The invention provides improved methods and apparatus for determining characteristics of a process--such as primary and second time constants, dead-time, and gain--by applying a doublet pulse to the process and measuring its response. By way of example, in one aspect of the invention, there is provided a method for generating a signal, .tau..sub.1, representing an estimate of a primary time constant of a non-self-regulating process, in accord with the mathematical expression .tau..sub.1 =(.delta.m.tau..sub.a.sup.2)/A.sup.+ is a factor representing the time-wise integration of the controlled variable during the period when the doublet pulse is being applied .delta.m is a factor representing an amount by which the manipulated variable is incremented, and .tau..sub.a represents the time period over which the controlled variable signal changes from its original value by a predetermined amount.