International Business Machines Corporation

Other

Neil R Davie

E Michael Coffey

Martin Aureliano Hassner

Razmik Karabed

Paul H Siegel

Duane W Baxter

Glenn Darrell Batalden

Thomas D Howell

Joseph C Lambiotte

A determination is made of the integrity of a gasket seal between two mating flange faces using capacitance measurement as an indication of the spacing between the flanges and thus the amount of gasket compression. The capacitance measurement can be made between a capacitor plate carried by the gasket and at least one of the flanges which serves as another capacitor plate. A capacitance-measuring instrument connected to the plates provides a measured capacitance signal that can be provided to a signal-processing instrument such as a personal computer. Further, the personal computer can be linked to a remote data center over a communications link for the transfer of gasket compression data.

Determination of gasket integrity by capacitance measurement

A thin flat disk-like capacitive load sensor of layered sandwich construction having a central opening and a circular outer periphery for installation above a packing follower or beneath the packing follower or packing gland. The load sensor has a thin first and second insulating outer layer between which an inner layer is secured. The inner layer is formed of dielectric material having a known dielectric constant, a first face having at least one thin electrically conductive circular ring surrounding the central opening in coaxial radially spaced relation, and a second face having a thin electrically conductive circular ring surrounding said central opening in coaxial radially spaced relation. The inner and outer layers contain electrical conductors engaged with respective electrically conductive circular rings on the opposed faces that are adapted to be connected with an electrical measurement apparatus. As the inner layer is compressed the spacing between the electrically conductive rings on the opposed faces is decreased such that compressive force on the packing can be measured as a function of the change in capacitance of the sensor. Proper compression of the padding can be achieved by monitoring during installation. Follow-up sampling or continuous measurement of packing compression provides early detection prior to packing failure to allow corrective action.

Valve packing gland pressure sensing by capacitance measurement

This disclosure concerns for generating asymmetrically constrained run-length-limited encoded data from a serialized binary string of 1's and 0's. The method comprises the steps of encoding the input data bits using a run-length-limited constraint in the form of M/N (d,k), where M is the number of input data bits, N is the number of output bits associated therewith, d is the minimum number of 0 data bits between adjacent data bit 1's, and k is the maximum number of 0 data bits between adjacent 1's; and alternating the values of d and k between a set (d.sub.1, k.sub.1) and a set (d.sub.2, k.sub.2), respectively, where d.sub.1 .noteq.d.sub.2. The apparatus comprises means for generating N output data bits in response to M input data bits and for generating data bit 0's between data bit 1's based upon a run-length-limited coding constraints (d.sub.1, k.sub.1) and (d.sub.2, k.sub.2), where constraints (d.sub.1, k.sub.1) and (d.sub.2, k.sub.2) apply alternately to runs of zeroes between output data ones. Fractional numerical values of d.sub.1 and d.sub.2 can be employed in the method or apparatus.

Method and apparatus for asymmetrical RLL coding

A magneto-optical player employs a differential readback circuit. The differential signal output of the readback circuit is low pass filtered. The filtered signal is converted to a single-ended signal and applied to a field effect transistor (FET). The FET is connected between one of the differential inputs of the readback circuit and a reference potential. The single-ended signal controls the FET to variably attenuate one side of the differential signal for reducing noise induced into the readback signal from diverse sources.

Readback circuits for magnetooptic players

Width restoring to eliminate unintended width variations in pulse width modulated data in combination with a phase lock loop allows pulse width modulated data in high density optical recordings. The width restoration is accomplished by detecting the timing relationship of the leading and trailing edges of pulses relative to expected timing for the leading and trailing edges. Expected time is derived from a phase locked loop or the original write signal. The detected timing is compared to the expected timing and the timing of the leading and trailing edge signals is corrected. Either analog or digital width correction techniques are used. Width restoration may be used while reading data or while writing the data.

Restoring and clocking pulse width modulated data

An optical file system in which a command to store data results in a write operation in the next available storage position. A single optical path is used for both reading and writing. By dividing the detector in two equal parts along the direction of relative movement, it is possible to determine whether data has been written at a position which is in advance of the center of the area viewed by the detector. The write operation is conditioned on the output of the first part of the detector. Since the first part of the detector gives advance warning on the status of the oncoming data position, it is possible to switch from reading to writing without the requirement for a wasted revolution or wasted space. By dividing the signal resulting from a change of reflectance sensed during a write operation by a measure of the intensity of the write laser a read signal free of the write modulation is obtained.

System for preventing the overwriting of previously optically recorded

In a xerographic printer wherein an acousto-optic modulator is used to derive a deflected first order beam of electromagnetic power which raster scans a charged photoconductor to leave a selectively discharged latent image area bordered by a discharged border area; power contents of said first order beam is maintained constant by adjusting the efficiency of the acousto-optic modulator with a closed loop electrical control system. The efficiency of the acousto-optic modulator is adjusted only when the beam is scanning the border area of the photoconductor.

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Tucson, AZ, United States of America

Neil R Davie