Abstract: An AC display excitation and synchronous display updating circuit for a digital electronic instrument in which the counter accumulating clock pulses representative of the magnitude of the quantity to be represented on the digital display is used as a frequency divider to obtain an AC display energizing signal whose frequency is reduced from the clock frequency to a suitable level for energizing the display. The contents of the continuously driven counter are synchronously transferred to the display register at the end of the conversion cycle by the use of a two-phase clock.

Abstract: In accordance with an illustrative embodiment of the present invention, a valve apparatus adapted for use in drill stem testing to apportion a pressure differential across two vertically spaced packers includes a housing mounted between the packers and having a flow passage leading from the exterior to the interior thereof, a first valve means including a spring-loaded mandrel arranged to close the passage at a preselected difference in pressures inside and outside the housing, and a second valve means that also can close the passage after a measured quantity of fluids has flowed through the passage.

Abstract: Apparatus for measuring the phase difference between two electrical signals Asin (wt+.theta.), Bsin (wt+.phi.), given a reference signal Vsin wt generated by the apparatus, comprises a phase lock loop for generating a clock frequency f = 360F where F is the frequency of the reference signal. This clock frequency f is then used to tune a 360 stage CCD transversal filter which is used to filter successively the two first-mentioned signals, whose phase difference is then measured by a zero intercept system. The clock frequency f is used to give phase difference in degrees.The phase lock loop comprises a 90-stage CCD to which the reference signal is applied. The output of the CCD is applied to one input of a phase sensitive detector whose other input is connected to receive the reference signal, and the control signal produced by the phase sensitive detector controls a voltage controlled oscillator whose output is applied to the clock input of the CCD.

Abstract: In a spectrum analyzer, the analogue signal to be analyzed is periodically sampled and digitized, and the digit samples are formed into R successive arrays each containing 2N successive samples and each overlapping the previous array by 50%. The forward Fourier transforms of each array are then successively formed, and an array of 2P complex points is formed from the result of each transform, where L-P/2 and L+P/2-1 are the points which represent the upper and lower limits of a Vernier band to be studied in detail and each array extends from points L-P to L+P-1 (i.e. each array is twice the width of the Vernier band, and the Vernier band is symmetrically disposed therein): additionally, each array for which L and R are odd is complemented. The arrays thus formed are then each multiplied by a window function (effectively equivalent to a band pass filter), and the result is subjected to the inverse Fourier transform to form respective further arrays of 2P points.

Abstract: A combination display window cover, tilt stand, and handle for a portable instrument, the unit serving each of these functions by virtue of an integrally formed appropriately shaped unit which can preferably be molded as a single piece of elastomeric material and does not introduce any substantial cost increase over and above a conventional handle. The invention is suited for use in conjunction with a portable instrument which includes a housing of generally parallelepiped configuration having relatively large area front and rear opposing surfaces and relatively small area top, bottom and opposing side surfaces, the housing having a display window extending across its front surface relatively near the top edge thereof and substantially parallel to the top edge.

Abstract: An interface circuit for use in a data transmission system is designed to be used not only between a highway and a device but also to link highways and can be commanded to enter a status in which commands sent to it on one highway are modified and sent out as commands on a second highway so that a controller device on the one highway can control devices not only on that highway but also on the second highway, with extension, if desired, to a third highway or beyond. To achieve this, the interface circuit has two ports each for connection to a respective one of two substantially identical highways, and status control means responsive to signals received at either port to establish different statuses of the interface. For inter-highway communication, the status control means is responsive to a command signal of particular form at either port to produce a modified command signal at the other port.

Abstract: The analogue storage circuit includes a charge transfer device such as a charge-coupled device (CCD) and a quantizing circuit. The charge transfer device is arranged to shift an analogue signal from its input to its output, the analogue signal being subject to a change in magnitude during such shifting.The quantizing circuit receives the analogue signal from the output of the charge transfer device and quantizes that signal at a respective one of several substantially discrete levels. The quantizing circuit is arranged to apply the quantized analogue signal to the input of the charge transfer device, whereby in operation the analogue signal is circulated round the loop defined by the charge transfer device and the quantizing circuit. The quantizing circuit is further arranged to quantize the analogue signal, upon each subsequent receipt thereof, at the same one of the discrete levels.

Abstract: A radiation gauge for measuring the profile of a moving strip, e.g. strip issuing from a strip rolling mill, comprises two X-ray tubes arranged on one side of the strip. The X-ray tubes are connected in push-pull configuration, for pulsing in alternation, and they each produce a respective curtain of radiation which intersects the strip in a respective straight line extending across the width of the strip, perpendicular to its direction of travel: these two straight lines are aligned with each other and overlap slightly in the center of the strip. A linear array of radiation detectors is disposed on the other side of the strip, so as to receive the radiation which passes through the strip. Signal processing circuitry processes the detector output signals to display the deviation of the thickness profile of the strip from a predetermined thickness profile.

Abstract: In accordance with an illustrative embodiment of the present invention, there is disclosed herein a device for anchoring downhole apparatus such as a safety valve in a tubing landing nipple, and a running tool for lowering the anchoring device at the end of a wire line into the tubing.The anchoring device comprises a body member that carries locking dogs which are shifted outwardly and engaged by the longitudinal movement of an expander mandrel. An expansible ring that is maintained on the mandrel by shear pins functions to lock the mandrel in the engaged position of the dogs. The running tool comprises a control sleeve having pivotally mounted connecting keys which remain engaged with the mandrel until the locking dogs are properly engaged and which then are released automatically from the mandrel. A safety shear pin makes it possible to free the running tool from the anchoring device in the event of incorrect anchoring of the latter and, when sheared, provides a "tell-tale" of incorrect installation.

Abstract: In the representative embodiment of the present invention disclosed herein, a nuclear-magnetism logging tool is arranged with at least its polarizing and detecting coil isolated in an enclosed chamber containing a uniquely-treated hydrogenous oil and preferably coupled to a suitable compensating system operatively arranged for responding to borehole pressure and temperature conditions. In particular, a selected, minor amount of a ferromagnetic colloid is dispersed in the oil in a sufficient concentration for uniquely effecting a controlled decay of nuclear magnetic noise signals from the coil-isolating oil, with this decay being of selected rapidity sufficient to avoid interference with the measurement of nuclear magnetic measurement signals from earth formations.

Abstract: A circuit for protecting speakers connected to the output of an audio amplifier. The output of the amplifier is connected to a filter which blocks normal audio frequency signals but passes both high and low frequency signals outside the normal audio range. The positive and negative filter output signals are connected respectively to the inverting and non-inverting inputs of an operational amplifier whose output is connected via a turn-on delay circuit to a speaker relay, which, when closed, connects the speaker to the amplifier. The turn-on delay circuit prevents speaker relay closure until turn-on transients have ended. If a DC voltage or a high frequency signal is present at the amplifier output, the operational amplifier generates a signal to open the relay thereby disconnecting the speaker from the amplifier output. The speaker relay quickly opens when power is turned off so that amplifier turn-off transients are not connected to the speaker either.

Abstract: In the representative embodiment of the apparatus of the present invention disclosed herein, a plurality of outwardly-biased bow springs are disposed around the lower end of the body of a spinner-type flowmeter and cooperatively arranged for centering at least that portion of the tool body in a well bore. The upper ends of the bow springs are pivotally secured to the tool body and their lower ends are coupled together below the body and adapted for longitudinal movement in relation thereto. To maintain the bow springs at a uniform spacing from the tool body when the flowmeter is in a deviated well bore, a corresponding number of rigid arms are pivotally coupled to the mid-portion of each spring and extended upwardly to a pivotal connection on a downwardly-biased collar which is slidably mounted on the tool body below the spring pivots. The spinner is provided with pivoted blades which are cooperatively arranged to be extended and retracted in response to the expansion and contraction of the bow springs.

Abstract: In the representative embodiments of the present invention disclosed herein, new and improved termination assemblies for multi-conductor electrical cables are manufactured by first molding a unitary fluid barrier around the cable conductors for integrally bonding or fusing this barrier around the conductor insulating sheaths so as to block fluid-leakage paths within the barrier and along the exterior of the conductor sheaths. The forward face of the barrier and the rear face of the contact support member of an electrical connector are also specially prepared so that as a selected thermosetting polymer, such as an unvulcanized elastomer, is subsequently molded to form a body individually surrounding each of the conductors extending ahead of the barrier, the now-vulcanized elastomer will be bonded to both the contact support member and the fluid barrier so to block fluid-leakage paths within the body and ahead of the fluid barrier which might otherwise intercommunicate the interiors of these sheaths.

Abstract: The data terminal is manually operable and is intended for communicating with a data processor. The terminal has a keyboard having a plurality of manually selectable keys, each of which represents a respective message to be communicated to the processor. A display is provided having a plurality of zones each corresponding to a respective key of the keyboard, and the display is arranged to display in each zone an indication of the message represented by the key corresponding to that zone. The keys are in the form of touch keys. Merely touching a key serves to manually select that key, and causes the visual appearance of the display to change, so as to indicate which key is selected. This change may for example be a reversal of the relative brightness of the corresponding zone of the display e.g. dark on light instead of light on dark. Actually depressing the key, as opposed to just touching it, produces an output signal for communicating the message represented by the selected key to the processor.

Abstract: A frequency counter is disclosed which determines the frequency of an input signal in a high speed and accurate manner. High speed is achieved by utilizing electronic digital processing circuitry. The high degree of accuracy is achieved by a combination of elements which perform period averaging of an integral number of periods of the input signal over a flexible measurement interval. The counter is particularly useful in accurately measuring low frequency signals.

Abstract: A moving coil instrument with a unique base of nonmagnetic sheet metal construction so arranged that sides of the base can flex to receive and clampingly retain a magnetic circuit, without causing movement of end portions of the base which support the moving coil for pivotal movement. Projections of a casing cooperate with circular mounting ears on the sides of the base to exert an inward force to assist the clamping action of the sides to securely hold the magnetic circuit against movement. A unique unitary sheet metal balance cross and a terminal plate assembly provide for connecting inner ends of taut bands which support the coil for movement. Cooperating tabs and slots on the coil, balance cross, and terminal assembly provide for securing the terminal plate and balance cross at opposite ends of the coil in predetermined locations with respect to the coil.

Abstract: In accordance with an illustrative embodiment of the present invention, a subsurface safety valve assembly includes a dome precharged with a set reference pressure that tends to close the valve, and means responsive to both ambient pressure and to the pressure of a control fluid for holding the valve open under normal conditions, a decrease in either control fluid pressure or tubing pressure, or both, enabling the dome pressure to cause the valve to automatically close and shut-in the well. The valve does not employ a coil spring to cause closure, which permits installation at great depths in a well, and a narrow spread between valve opening and closing pressures.