Abstract: A multi-plate, anti-cavitation fluid pressure reduction device includes a stack of annular plates having a hollow center, a fluid inlet at an inner perimeter thereof and a fluid outlet at an outer perimeter thereof. Selected ones of the plates each define at least one pressure reduction stage including an orifice having a well-rounded or well-tapered inlet and an abrupt discharge, and a communication passage coupled to the discharge. Each pressure reduction stage communicates with another pressure reduction stage in an adjacent one of the annular plates in the stack. Two or more pressure reduction stages are coupled in series to define a pressure reduction flow path from the fluid inlet to the fluid outlet. Each pressure reduction stage is preferably characterized by a velocity head loss greater than 75% and a corresponding pressure recovery less than 25%. The fluid pressure reduction device is typically incorporated into a fluid control valve.

Abstract: The concentration of an analyte in a fluid is measured by a quartz crystal microbalance sensor device in the fluid containing a concentration of the analyte. The sensor device exhibits a resonant frequency representative of the concentration of the analyte in the fluid. A quartz crystal microbalance reference device has a resonant frequency lower, by a predetermined amount, than the initial resonant frequency of the sensor device before the sensor device is exposed to the analyte. A signal is derived based on the difference of the resonant frequencies of the sensor and the reference device, and a first counter counts a predetermined number of cycles of the difference signal frequency to derive a sample time period. A second counter counts cycles of a clock signal frequency during the sample time period to derive a count representative of the difference signal frequency.

Abstract: A taper nut retention device mechanically fastens a plurality of pressure reduction disks. A cage end member at one end of the stacked disks has a series of counterbores, each aligned with respective mounting holes in each disk. A second cage end member at the other end of the stack has a series of inwardly converging, tapered bores with shallow taper angles, each aligned with respective mounting holes and a counterbore. A taper nut with a threaded interior and an outer tapered surface with a shallow taper angle matching the tapered bore is inserted into and engageably contacts the tapered bore. A threaded bolt is inserted into the counterbore and through the disk mounting holes to threadably engage the taper nut. Tightening of the bolt and nut mechanically secures the stacked disk assembly. A process for making the stacked disk assembly wherein each disk and the cage end members are plated with nickel and the components are fused together in a brazing oven.

Abstract: An interface between a remote communications network and a process control system includes a storage device, a communication software stack and a user software layer. The user software layer enables interfacing between the remote communications network and the process control system by directing the communication software stack to operate in the process control system using a process communication protocol, by monitoring the message traffic on the communication software stack, and by copying requested message traffic to the storage device. The user software layer also includes media interface software that allows access to the storage device by the remote communications network to thereby deliver specific data to a device connected to the remote communications network.

Abstract: A diagnostic test unit for deterministically measuring one or more parameters, such as dead band, dead time, response time, gain, or overshoot, of a process control device that is connected in a process control loop during operation of a process includes a switch controller, a signal generator, a switch, a response accumulator mechanism, and an analyzer mechanism. The switch controller monitors a process signal during operation of the process to determine whether the process signal is substantially stable. In the event that the process signal is substantially stable, the switch replaces a control signal with a diagnostic test signal generated by the signal generator. The response accumulator is in communication with the process control loop to obtain an indication of the response of the process control device to the diagnostic test signal. The analyzer unit then determines the device parameter from the test signal and the response indication.

Abstract: An emergency shutdown system for a process control system includes an emergency shutdown (ESD) valve and an associated valve actuator. An emergency shutdown (ESD) controller provides output signals to the ESD valve in the event of a failure in the process control system. A solenoid valve responds to the ESD controller to vent the actuator to a fail state. A digital valve controller (DVC) test strokes the ESD valve. An impedance booster device enables the dc powering of the solenoid valve and the DVC over a two wire line while still permitting digital communication over the same two wire line.

Abstract: An intelligent pressure regulator for maintaining a fluid in a process at a predetermined pressure includes an electronic controller which enhances regulator performance and provides self-diagnostics and communications capabilities. The electronic controller includes a pressure sensor which provides a signal indicating the pressure of the fluid being controlled, an adjusting pressure for adjusting the position of a throttling element; and a PID controller which receives the signal indicating the pressure of the fluid being controlled and applies the adjusting pressure to the actuator in response to the signal.

Abstract: A single-piece flow-control assembly is configured to be disposed within a pit assembly in a manner which allows the flow-control assembly to be easily and quickly removed and replaced. The flow-control assembly includes one or more regulators rigidly connected to a mounting assembly having two coupling mechanisms adapted to rigidly mount to at least one of a fluid inlet pipe or a fluid outlet pipe at locations away from the ends of these pipes. The coupling mechanisms provide a sealed engagement between the ends of the flow-control assembly and the fluid inlet pipe and the fluid outlet pipe when the flow-control assembly is properly installed within the pit assembly. A fluid passageway with a 180 degree bend therein may be provided as part of the flow-control assembly so that the coupling mechanisms simultaneously couple to or decouple from the fluid inlet and outlet pipes by movement of the flow-control assembly in one direction.

Abstract: An electrical circuit and method for measuring small variations in a high frequency signal is disclosed. The circuit generates a coarse measurement of the input signal frequency and a reference signal having the same frequency as the frequency represented by the coarse measurement. The circuit measures the difference in frequency between the input signal and the reference signal, and adds the coarse measurement and the difference measurement to determine the frequency of the input signal. The circuit may be used in conjunction with a piezoelectric acoustic wave device and oscillator to provide an apparatus for accurately measuring low concentrations of a gas.

Abstract: A device and method that automatically tune a valve controller coupled to a process control loop generate a plurality of sets of tuning parameters for use by the controller, deliver a test signal, such as a blocked sinusoidal signal, to the controller to force the process control loop through a test cycle while each of the plurality of sets of tuning parameters are being used by the controller and measure a response of the process control loop during each of the test cycles. The device and method then calculate a performance index for each of the plurality of sets of tuning parameters based on the measured responses and select one of the sets of tuning parameters based on the calculated performance indices. The selected set of tuning parameters is then loaded into the controller for use during normal operation of the process control loop.

Abstract: A fluid control valve having a valve body, a cage, and a flexible elastomeric diaphragm with a formed convolution to fully open the cage opening. An elastomeric diaphragm regulator with a flow diverter in the fluid flow path to reduce fluid flow separation and thereby reduce the required flow recovery area before pressure throttling. A raised knife edge seat located on the cage top in a position of stagnant fluid flow to reduce the build-up of contaminants on the seat. An elastomeric diaphragm regulator with a valve actuator coupled to a guided valve stem attached to the regulator diaphragm.

Abstract: A fluid pressure reduction device with tortuous flow paths in stacked disks. The fluid flow outlets are maintained independent by directed flow paths to avoid flow collisions in the exiting flow streams. A flow straightening section includes an inwardly tapered end section at the fluid flow outlets. Splitting of a tortuous flow path into at least two sub-flow paths with balancing of the mass flow between the sub-flow paths.

Abstract: A schematic generator for use in a process control network, in which control functions are implemented by field devices interconnected at various and distributed locations on a bus, polls each of the field devices to retrieve information pertaining to the identity of the device, the identity of the control functions associated with the device, the manner in which the device communicates with other devices with respect to each of the control functions associated with that device, the timing associated with the execution of each of the control functions of that device and the timing of the communication activities associated with each of the control functions of that device. The schematic generator then analyses the retrieved data to identify the manner in which the devices are physically connected on the bus and the manner in which the different control functions are interconnected over the bus to perform process control loops within the process control network.

Abstract: A rotary valve actuator and linkage include an actuator having a tubular housing with end caps and a piston that is moved by fluid pressure against a compression spring. A rolling diaphragm is used to bias the piston. A pair of ports are provided on opposite sides of the housing, and a linkage having two arms is interconnected with the piston through the ports. The linkage is coupled to a rotary valve shaft and linear movement of the piston causes rotational movement of the shaft. The linkage includes two separate arms and a centerpiece. In one embodiment, the arms and the centerpiece interengage each other at angled surfaces that force the centerpiece and the arms into radial engagement with the shaft when axial compression is provided to the arms and centerpiece to force them toward each other. In another embodiment, each of the linkage arms is provided with a collet having radially movable portions.

Abstract: A displacement sensor includes a magnet assembly having a housing for mounting to one of first and second relatively moveable elements. First and second magnets are mounted to the magnet assembly housing so that the north pole of one magnet confronts the south pole of the other magnet, and vice versa. The first and second magnets form a longitudinal space between them. A flux-shaping pole piece on each of the poles have configurations to sculpt fringing magnetic flux in the longitudinal space so that magnetic flux density in the longitudinal space varies substantially linearly along a line in the longitudinal space between the confronting poles of the magnets. A magnetic field sensor assembly has a housing for mounting to the other of the first and second elements. A magnetic flux sensor is mounted to the sensor housing on the line in the longitudinal space between the first and second magnets.

Abstract: An intelligent pressure regulator for maintaining a fluid in a process at a predetermined pressure includes an electronic controller which enhances regulator performance and provides self-diagnostics and communications capabilities. The electronic controller includes a pressure sensor which provides a signal indicating the pressure of the fluid being controlled, an adjusting pressure for adjusting the position of a throttling element; and a PID controller which receives the signal indicating the pressure of the fluid being controlled and applies the adjusting pressure to the actuator in response to the signal.

Abstract: A device for delivering a metered quantity of vaporized liquid material to the surrounding atmosphere is disclosed. The device includes a reservoir for storing the liquid material, and a conduit in flow communication with the reservoir, with a portion of the conduit defining a dosing chamber for storing the metered quantity of the liquid material. The conduit further includes an impeding portion for restricting the flow of the liquid material from the dosing chamber toward the reservoir. An outlet nozzle is provided and is in flow communication with the dosing chamber. A thermal activator is disposed adjacent the dosing chamber for vaporizing the liquid material in the dosing chamber thereby ejecting the vaporized material through the outlet nozzle to the atmosphere.

Abstract: Functional elements within a two-wire, loop-powered, two-way digital communications environment are interconnected using selective redundant connections and selective redundant functional elements. The redundant functional elements and redundant connections provide a smooth transition from operation of a primary process loop element to a secondary process loop element in the event of a failure of the primary process loop element. Redundancy is selectively implemented using a redundant pair of field devices or a redundant bus pair having a primary bus and a redundant bus. In a first case, redundancy is selectively implemented using a single set of communication media, such as a single communication loop, but implementing redundant functional elements, such as field devices, so that recovery is achieved upon failure of a functional element but not upon failure of the communication media.

Abstract: A system and method for debugging and tuning a process control network having distributed control functions implemented by a set of field devices communicatively linked over a bus includes an operational scheduler that schedules the execution of each of a number of process control functions and communication functions performed by the field devices to define a process control scheme and an indicator that indicates one or more process control scheme locations at which the process control scheme is to be automatically or conditionally interrupted to thereby enable debugging and/or tuning of the process control network. A controller interrupts execution of the process control scheme at the indicated flow locations, communicates process data to a user to display the current or a past state of the process to a user and waits for user input before continuing with operation of the process control scheme.

Abstract: A fuzzy control system for industrial process control utilizes an auxiliary process variable to determine which of several regions of different gain a non-linear process is operating. Based upon that determination and fuzzy input signals, the fuzzy controller provides a process control signal which corresponds to that region.