Abstract: There is provided a fault tolerant clock system for a synchronous design using N-way combinatorial voting schemes for N greater than 3. The system comprises a plurality of clock circuits for generating clock signals and a voting circuit that is connected to each clock circuit for receiving the clock signals and generating an output signal. The voting circuit produces an output signal that is in agreement with a majority of the clock signals and maintains the output signal at a previous output level when the majority of the clock signals is not detected by the voting circuit. From another viewpoint, the voting circuit maintains the output signal at the previous current level when a minority of agreeing clock signals is not detected by the voting circuit.

Abstract: An improved immersible magnetically-coupled mixer has a plurality of rollable bearing assemblies readily cleanable by flushing in place and easily removable and replaceable without damage to either the mixer impeller or the bearings. The rollable bearings are resistant to corrosion, capable of running without lubrication, and have low propensity for batch contamination through wear. The rolling and fixed elements of the bearings are impervious to attack by the process materials being mixed, the rollable elements, preferably balls, can be formed of a hybrid ceramic such as silicon nitride, and the races can be formed of a nickel-beryllium or cobalt-chromium-tungsten alloy.

Abstract: An improved immersible magnetically-coupled mixer has rollable bearings readily cleanable by flushing in place and easily removable and replaceable without damage to either the mixer impeller or the bearings. The rollable bearings are resistant to corrosion, capable of running without lubrication, and have low propensity for batch contamination through wear. The rolling and fixed elements of the bearings are impervious to attack by the process materials being mixed, the rollable elements, preferably balls, being formed of a hybrid ceramic such as silicon nitride, and the races being formed of either a nickel-beryllium or cobalt-chromium-tungsten alloy. A mixer impeller having a central bore is rotatably mounted on the rollable bearings on a fixed impeller shaft attached to the inner wall of a vessel at the bottom of the mixing space, which shaft extends through the impeller bore. The impeller contains magnets and is couplable in driving relationship to an external magnetic mixer drive.

Abstract: The illumination of a photolithographic projection imager is given a variable annular intensity profile by using diverging and counter diverging elements that are movable relative to each other in the illumination path. An upstream element diverges the illumination into an annular configuration, the radius of which is set by the distance downstream to the counter diverging element. Convex and concave conical surfaces on the movable elements can accomplish this.

Abstract: There is provided a conveyor system having a conveyor belt for continuously transporting materials from a feed hopper to an end feed mechanism and a means for continuously weighing the bulk material as they pass over the weigh span of the conveyor belt. The conveyor system comprises a continuous conveyor belt disposed about a pair of pulleys for transporting a material from a feed hopper to a feed mechanism, at least one pair of support rollers, and a weigh assembly having a weigh roller means for continuously determining the weight of materials within the weigh span of the conveyor belt. The support rollers are positioned under the upper portion of the conveyor belt and spaced apart to define the boundaries of the weigh span. Moreover, the support rollers are disposed on opposite sides of the weigh roller wherein the pitch between each support roller and the weigh roller are identical and wherein the support rollers and the weigh roller are on the same horizontal plane.

Abstract: A crystal-pulling apparatus incorporates a temperature sensor and an adjustable radiation shield. The temperature sensor measures temperatures of a melt surface adjacent to a solidification interface between a crystal and the melt. The radiation shield regulates radiational cooling of the melt. A control system adjusts the radiation shield in response to changes in the measured temperature of the melt for enhancing dislocation-free growth of the crystal.

Abstract: A switch for use in transformer tap changing is modular in design, having standardized fixed contact units mounted in alignment on a base. Each contact unit has an electrical contact embedded in an insulating body, with a hollow bore formed through the insulating body and the embedded electrical contact. A cylindrical movable contactor having spaced contact bands is mounted on a shaft to be driven through the hollow bores of the fixed contact units between positions at which its contact bands engage the electrical contacts within adjacent fixed contact units. The electrical contacts of the fixed contact units are connected to different taps of the transformer to allow the transformer turns ratio to be adjusted by changing the position of the movable contactor. The drive shaft is connected by a mechanism to a handle mounted outside the tank of the transformer that can be operated to move the movable contact a selected distance to change the tap connections to the transformer.

Abstract: A door holder assembly for use with an associated electromagnet and an associated door having a pneumatic or hydraulic door closer mechanism mounted thereon which includes an elongated body having first and second axial portions. The apparatus includes a threaded member coupled to the first axial portion and to the second axial portion, the threaded member is coupled to one of the axial portions by mating threaded surfaces whereby relative rotation of the first and second axial portions varies the combined axial extent of the elongated body. The assembly further including a plate at one end of the elongated body and a base at the other end of the elongated body, the base and the plate are each mounted on the elongated body by means that allows relative angular movement therebetween. In some forms of the invention the first and second axial portions are disposed in telescoping relationship and each of the axial portions are cylindrical.

Abstract: A FIFO memory eliminates the delay associated with selecting memory locations during a read and write operation and prevents data intended to be saved from changing during the write operation. The FIFO memory includes a shift register having a plurality of memory locations, data input and data output terminals coupled to the memory, a first memory location coupled to the data output terminal that is immediately output enabled in response to a read operation, and a single pointer arrangement coupled to the memory locations for selectively saving data contents in successive memory locations coincidentally with the occurrence of successive write operations.

Abstract: Instabilities in the output voltage provided from an AC power supply system such as an uninterruptible power supply connected to a power factor correcting load are suppressed by a dynamic voltage regulation stabilizer system which is connected across the output lines from the power supply system to the load. The DVR stabilizer system includes a rectifier connected to the power supply system output lines. A capacitor is connected across the output nodes of the rectifier. Switching devices form a bridge that connects the capacitor to the output lines. Selected switching devices in the bridge are turned on for a selected duration encompassing the time of the peak of each half-cycle of the AC voltage waveform provided by the power supply system. During normal operation, where the peak AC voltage from the power supply system is substantially constant, the capacitor charges up through the rectifier to a voltage level near the peak value of the AC voltage waveform.

Abstract: There is provided an alarm system for detecting and warning of the presence of alarm and trouble conditions in a plurality of zones. The system comprises a loop controller having supply lines extending to the plurality of zones and a module connected to the supply lines within each zones. The module includes means for detecting whether communication between the module and the loop controller has been disrupted. If an alarm condition occurs in a particular zone, the module initiates communication of the alarm condition to the loop controller. During normal operation, when communication with the loop controller has not been disrupted, the module has shared operations with the loop controller to determine whether an alarm condition exists. When communication with said loop controller has been disrupted, temporarily or otherwise, the module continues to operate independently of the loop controller and determines whether an alarm condition exists.

Abstract: A panel sub-system for a life safety system having a plurality of inter-connected panels, each panel including a local rail, and a plurality of modules, each comprising a module circuit board, inter-connected by the local rail. The first of the modules have a central processing unit, and the remainder I/O modules having a variety of functions, as well as at least two channel members containing respective rail circuit boards defining each local rail. Moreover, each board has spaced electrical connectors for connecting to the respective module circuit boards.

Abstract: A labyrinth shaft seal for preventing the migration of gear lubricant from a mixer drive assembly into a batch of process materials being mixed. In the preferred embodiment, a portion of the gearcase outboard of the upper quill bearing, preferably the actual bearing mount, is provided with an axially-directed circular face, the mount being formed of relatively soft material such as ductile cast iron. A disc-shaped seal element having a central aperture and supporting an axially-directed peripheral cylindrical flange is sealingly mounted on the quill above the quill bearing and extends radially from the quill and generally parallel to the circular face. The flange is formed of material substantially harder than the circular face.

Abstract: A refrigeration heat exchanger section useful in circulating a substantially non-CFC refrigerant mixture which comprises: a compressor means, an auxiliary condenser, a first condenser, a second condenser, a third condenser, a subcooler and a liquid/gas separator, wherein a subcooled refrigerant liquid mixture taken as bottoms from the liquid/gas separator is distributed and expanded by a first expansion means and a second expansion means to form first and second expanded streams, respectively, such that the first expanded stream is returned to the auxiliary condenser and compressor in order to avoid overheating of the compressor.

Abstract: There is provided an alarm system for detecting and warning of the presence of alarm and trouble conditions in a plurality of zones. The system comprises a loop controller having supply lines extending to the plurality of zones and a module connected to the supply lines within each zones. If an alarm condition occurs in a particular zone, the module initiates communication of the alarm condition to the loop controller. The system also includes means for variably controlling a specific personality of the module, such as a microcontroller, so that the module functions selectively in a variety of specific ways. The means for variably controlling includes means for selectively storing configuration data, such as an EEPROM, in the module to define the specific personality.

Abstract: An illuminated exit sign having at least one chevron-shaped opening on its outer surface and a replaceable directional arrow cover that is substantially similar in shape to the opening and removable from the opening in order to selectively indicate an exit direction. A shoulder which is formed in the cover is adapted to abut with a shoulder formed at the opening. At least two snap tabs located on opposite sides of the arrow cover fit securely within corresponding notches disposed in the shoulder formed at the opening. The opposing configuration of the shoulders and the corresponding configuration of the snap tabs and notches facilitate the removal and replacement of the arrow by a single, quick snapping action which secures the cover in a snug, flush fit.

Abstract: There is provided an system and method for calibrating weigh assemblies of bulk material feeders using test chains of known weight and pitch. In particular, the present invention is a calibration checking system for a belt-type gravimetric feeder or conveyor having a weigh span section and comprises a continuous conveyor belt, at least one pair of support rollers and at least one weigh roller. A particular weigh roller is disposed under an upper strand of the conveyor belt and equidistant from each of the support rollers so that they are in planar alignment with one another. The calibration checking assembly also comprises a test chain having a chain pitch that is integrally divisible into the pitch of the weigh span section. In addition, portions of the conveyor belt on both sides of the weigh span are inclined equally at a single particular angle relative to the weigh span section.

Abstract: A line monitor uses two wire data transmission in a fire alarm and detection system. A line voltage monitoring mechanism is within each wiring/contact monitoring circuit such that the exact value at any time of varying source voltage is known. The monitoring current resultant from the monitoring arrangement is strictly a function of impedance and not a function of source voltage because a line-monitoring scaling factor is incorporated into the final calculation. The monitoring scheme also results in the alarm and trouble voltage thresholds being suitably altered to take account of changed line voltage conditions.

Abstract: There is provided a synchronous strobe system for synchronizing a flash rate of a plurality of strobe devices positioned along a loop of an alarm system. After the alarm system is energized and activated, a control panel of the synchronous strobe system will transmit a synchronization signal or pulse along the loop at periodic time intervals. Each synchronization signal is detected by a electronic circuit of the strobe device, including a microcontroller. Upon detection of each synchronization signal, the microcontroller determines whether to operate the strobe device in Sync required mode or Sync not required mode. For Sync required mode, the synchronization signal must be detected by the strobe device to flash a strobe light of the strobe device. Otherwise, the microcontroller waits for the next synchronization signal before attempting to flash the strobe light.