Abstract: A mixer seal assembly for a closable vessel having a dynamic mixer shaft seal in a bore in a vessel flange and a static seal for vessel transport formable by insertion of a disconnected lower portion of a fast connect coupling which is fast to install on the mixer shaft into the flange bore above the dynamic seal. The resulting seal assembly can seal the vessel for over-the-road transport. The dynamic seal includes a circular lip which sealingly engages the surface of the mixer shaft. The static seal includes an O-ring disposed in a first annular groove in the coupling portion. A shaft bushing disposed adjacent to the shaft seal in the flange bore minimizes shaft runout in the shaft seal and permits use of relatively rigid and dry running materials such as fluorocarbon polymer in the shaft seal.

Abstract: In order to extend the life of mixing impellers which circulate materials, and particularly which suspend solids, in the form of particles which erode the blades of the impellers and place a practical limit on impeller speed and/or angle of attack due to increased erosion at high flow velocity (erosion being a function of the cube of the velocity), the blades are constructed from blades into an airfoil configuration which does not limit the thickness of the plates and thereby allows the use of thick plates having extended life. An erosion resistant layer is located at least over the leading edge region of the blade and the shape of the blade reduces velocity of flow over the leading edge; the camber of the blade being maximized midway between the leading and trailing edge. The suction surface of the blade in the region subject to erosion is continuous thereby avoiding discontinuities which form vortices which enhance erosion.

Abstract: In order to circulate a two-phase system (a suspension of solid particles in liquid) in a large (e.g., 100 ft. diameter) and shallow tank (e.g., where the liquid level, Z, to tank diameter, T, ratio is 0.4), a cluster of side entering mixers is used and a desired flow pattern (much like that obtained from a top entering mixer) along the bottom and top of the material in the tank and vertically along the walls of the tank is obtained by (a) rotating an end mixer in the cluster in opposite sense to the other mixers, (b) spacing the mixers so that the interference is reduced between the flow produced by the mixers at the wall of the tank opposite from the mixers, and (c) by tilting the mixers so that the flow intersects the bottom near the wall of the tanks opposite from the mixers.

Abstract: In order to obtain efficient gas dispersion (aeration where air is the gas) in mixing systems where the circulating impeller is offset from the center of the tank containing the medium in which the gas is dispersed or sparged while being circulated, flooding of the impeller due to entrainment of gas released by the sparging device (a pipe or ring having as outlets) because of the asymmetrical return flow of the medium circulating in the tank which entrains the gas and brings the gas into the area swept by the impeller as it rotates, is avoided by arranging the sparging device to prohibit the release of gas into a region, including a sector of the swept area, where the return flow responsible for flooding occurs. This sector has been found to lie along a line between the center of the tank and the axis of rotation of the impeller. The gas dispersion mixing system is especially useful in dispersion of gas into large volumes (e.g. 20,000 cubic feet).

Abstract: The invention describes a method and apparatus for effecting vital functions notwithstanding the fact that non-vital hardware is employed. A vital processor is implemented using non-vital hardware in the form of a digital computer which may for example be a microprocessor. The vital processor accepts binary input values and, based on a series of logical expressions relating output values to input values, determines the appropriate output values. Rather than employing a single bit to represent the condition of a particular input or output, unique multibit binary values or names are used. Each input or output has assigned to it at least two unique multibit values, each satisfying the code rules of a different code. Thus rather than representing a closed contact as a single 1 bit, and an open contact as a single 0 bit, in accordance with the invention the closed contact is represented by a unique multibit name which satisfies the code rules of a first code.

Abstract: This invention relates to a complete double lap lapping and polishing machine particularly to an apparatus designed to finish to a required thickness and/or finished polish workpieces such as thin silicon and/or ceramic wafers. The machine includes improvements in all of it's substructure components, including it's overall housing design, planetary gear drive, fluid cooling systems, positioning and locking of the upper lap plate in an inoperative position, an automatic thickness or sizing control, rotary union with automatic fluid liquid indicator and a slurry delivery and recovery system, all of which result in a more automated efficient use of the machine so as to produce a closer tolerance finished product.

Abstract: A truck having a pair of wheels mounted by individual stub axles to longitudinal members of a frame. Lateral members of the frame received the forces from the wheels via the longitudinal members and forces from the car via air springs mounted to the lateral members adjacent the longitudinal members. The stub axles are easily removed from U-shaped retainers. A sleeve through the hollow axis retains the bearings to the axle. Half shafts interconnect a gear box and the stub axles for driven trucks and the interconnections are dimensioned to allow the shafts to be removed axially through the hollow axle.

Abstract: A device for automatically sizing (thickness control) a workpiece of a double wheeled lapping machine, during the lapping process with simultaneous runout of the lower lap compensation. The device provides an annular ring attached in parallelism to the upper plate, together with a roller follower having contact with the under surface of the ring, with the follower pivoted upon an adjustable mounting arm attached to a vertically extending stationary post mounted beyond the circumference of the ring on a supporting shelf formed as a part of the machine casing. A movement responsive probe is in contact with the follower and responds to any deviation in flatness of the workpiece as it is transmitted therefrom onto the lapping surfaces of dual lap plates during the lapping thereof.

Abstract: An optical focus sensing system is disclosed. The system provides a focus shift measurement capability utilizing the relative motion between two gratings to produce different diffraction orders which are separately detected by a pair of detectors to form signals having a phase difference proportional to the focus error corresponding to the planes occupied by the two gratings. A control circuit is responsive to the phase difference between the signals from the two detectors to provide a controllable focusing capability.

Abstract: Apparatus for mixing or circulating a liquid or a liquid suspension (slurry) to provide efficiently, high head so as to enable slurries which are viscous or contain large or heavy particles or tend to agglomerate to be mixed or circulated, uses an impeller which provides a head coefficient, k.sub.v from about 3 to 10 at high hydraulic efficiency. The impeller has a plurality of blades with a tip configuration which develops the high head where the blades are wider at the tip than at the base and have fins disposed above and below the blades and at the way of a draft tube wherein axial flow is produced.

Abstract: A frame synchronization detection system which enables frame synchronization and synchronizing pulses to be provided from at least two formats of DS1 TDM signals, specifically the D4 and extended superframe Fe formats. A first search logic circuit provides an output indicating the onset of a maintenance mode of frame detection when either Fe or D4 patterns are decoded. For the D4 pattern an alternate pattern is decoded and the first search circuit enters the maintenance mode only after both alternate D4 framing patterns are decoded. A second search logic circuit enables the decoding of a subsequent sequence and detection of framing, thereby reducing the probability of false framing. A frame counter which is synchronized upon the detection of a valid framing pattern by the first search circuit continues to supply frame sync pulses until an error detector, which detects whether a predetermined ratio of invalid to valid framing bits occurs, resets the system back to the search mode.

Abstract: A table stabilization assembly is disclosed. The assembly is intended for use in a microlithography system which includes a stable for supporting a movable stage and a frame support for supporting the table. The assembly includes a pair of brake leaves which are respectively attached to the table and frame support and which are clamped together during stage acceleration or deceleration to provide stabilization.

Abstract: Mixing apparatus having a sealed impeller shaft provided by a seal unit which supports the shaft and to which a motor drive unit may be detachably connected. When the motor drive unit is disconnected, the mixing apparatus may be sterilized, along or together with the vessel containing the material to be mixed and to which the seal unit is attached. The seal unit has a seal assembly with a movable part engageable by a drive shaft in the drive unit when the drive unit is mounted on the seal unit. The movable seal part is biased to move to a position against a mounting plate on which the drive unit is mounted when the drive mounted is removed so as to provide a static seal. When the drive unit is attached to the seal unit, the driven shaft engages the moveable seal unit part and moves it to another position away from the mounting plate, where the seal assembly may freely rotate with the impeller shaft and maintain a dynamic seal.

Abstract: A method for vital memory management of data. A method is disclosed for clearing on specified conditions and for assuring the clearing is effected. Both random access and stack operation are implemented. Clearing the memory area requires reading the contents of a given location and, assuming expected data is read, going on to process the next memory location. In one embodiment the contents of the given location are used to access the next location, thereby assuring that if unexpected data is read the process will not proceed normally.

Abstract: Broken rail detection in a block of track without the need or expense of conventional signalling uses a chain of transmitters and receivers connected to the rails and defining sections of the block between the ends of the block. Either cyclically at a predetermined code rate or upon command of an external unit; an alternating current (AC) signal is launched from one end of the block and is repeated at different frequencies in each of the sections. When received at the end of the block, an indication of the absence of a broken rail condition is given either (a) by way of pole line or radio communication to a central control or dispatcher point and thence back to the trains, or (b) signals at the ends of the block are flashed at the code rate. The detected signal at the code rate may be used to modulate a direct current which is transmitted along the rails in the block to a signal at the opposite end of the block which also flashes at the code rate to indicate a safe condition.

Abstract: Apparatus for mixing liquid and liquid suspension mediums in vessels with a mixing impeller shaft system of a composite of fibrous and plastic material of a structural configuration to enable the use of such material in commercial and industrial applications where the reaction loads of the medium on the system militate against the use of composite fibrous and plastic material. The system utilizes impellers having blades which distribute the reaction load through a hub on a mounting area of a shaft with keys and keyways in a manner to avoid stress risers unamicable to the composite material and which can cause failure thereof. Separate keys and keyways are provided to oppose the thrust due to the reaction loads and to oppose the torque due to such loads. Plural thrust keyways may be used to enable the impeller to be located at different positions on the shaft and at selected heights above the floor of the mixing vessel.

Abstract: An end connection for a shaft made of composite material, which accommodates for differences in stiffness, thermal expansion, chemical resistance between the shaft and the member connected thereto and operates under oscillating torque, thrust, and bending loads, and also provides for manufacturing flexibility in enabling the shaft and connection to be produced as separate parts which are formed when final assembly is to occur. The connection has a male insert which is inserted into the end of the composite shaft. Axial and circumferential grooves in the surfaces of the male insert and the shaft. These grooves are aligned to form circumferential and axial keyways which intersect each other. Material is injected into the keyway and polymerizes to form structural keys which transmit the thrust and torque, while locking the insert member and the shaft permanently together. The bending loads are transmitted through the tight fit extending axially between the shaft, insert member and keys.

Abstract: A fixture for dressing the polishing surfaces of a platen to maintain it in a planar condition, including a flexible carrier which is adapted to be rotated independently of the rotation of the surface to be dressed, with the carrier providing an opening for the placement therein of a dressing pad. About the edges of the opening there are provided a plurality of driving keys which will engage appropriate edge surfaces of the dressing pad for effecting rotation of the dressing pad with the flexible carrier relative to the surface to be dressed.

Abstract: Mixer drive apparatus, which provides gear reduction for driving the impeller shaft of the mixer. A drive shaft from an electric motor is parallel to the impeller shaft which extends through a support collar of a housing. The collar has a hole therethrough through which the impeller shaft extends into the housing. A hub is rotatably mounted on the outside of the housing and carries a gear which is coupled to a pinion on the motor drive shaft. A coupling is attached to the hub and bridges the hole in the collar. The end of the impeller shaft is cantilevered and overhung from the coupling. A gap is defined between the impeller shaft and the inside surface of the support collar which is adapted to receive a seal assembly. The seal assembly includes a retainer hub which captures a sleeve containing the seal structure in the gap between the coupling and the retainer.