Abstract: A labyrinth articulation joint (38) for use in the seal frame (35) of a rotary regenerative air heater (20). An internal labyrinth arrangement of intercooperating tabs (54,55) and slots (44,45) in the two hinges (41,51) of the labyrinth articulation joint (38) present a series of successive right angle turns that increases the pressure drop through the labyrinth articulation joint (38) thus reducing the leakage of air through the labyrinth articulation joint (38), and thereby minimizing erosion of the labyrinth articulation joint (38) due to abrasive particles that would otherwise be carried through the joint by the leakage air.

Abstract: Supervisory control system including an arrangement and process for controlling the operation of a dryer for the continuous adiabatic drying of a moist solid product with heated air for achieving the desired final product moisture content which would not exceed scorch level.

Abstract: A method and apparatus for measuring mass flow of a fluid flow in a conduit includes separating the flow into two separate conduits or tubes. The two tubes are oscillated at oscillation portions one portion being 180.degree. out of phase with the other. The oscillation portions are located on each side of midpoints of respective tubes. Velocity, distance, acceleration and phase of oscillation of the midpoints or sensing location near the midpoints of the tubes is measured which measurement corresponds to the mass flow rate of the fluid flow.

Abstract: An improved power supply for power switches arranged in a totem pole configuration is disclosed. A single power supply, having an output voltage substantially less than the voltage applied to the upper power switch, periodically charges a capacitor within a flying capacitor circuit. Microprocessor based control circuitry controls the charging and discharging of the capacitor and the periodic operation of the power switches resulting in the voltage at the output of the power switches being at system common or at the voltage applied to the upper power switch.

Abstract: An ultrasonic apparatus and method for testing a material comprises an oscillator which generates a selected frequency in the ultrasonic range. A transducer is connected to the oscillator for applying an ultrasonic signal to the material and for receiving an echo signal back from the material. Two phase detectors are utilized one of which receives the echo signal and an in-phase oscillator signal to generate a first display signal, and the other of which receives a quadrature signal which is 90.degree. out of phase from the oscillator signal, as well as the echo signal to generate a second display signal. The first and second display signals are utilized in a visual display such as a cathode ray tube, to generate an image. The image changes according to the phase shift between the ultrasonic signal transmitted into the material and the echo signal, which, in turn, can be utilized to determine the presence and depth of a flaw or boundary in the material.

Abstract: An adaptive gain surge control system (18) is disclosed for a centrifugal compressor (14) which reacts to both normal and emergency surge conditions by controlling a bypass valve (48) across the compressor (14) inlet and outlet in response to a variable gain (G) determined by the offset (d) of the surge control line from the surge line of the compressor.

Abstract: A vacuum sealing device includes a plug which is thrust into the port of an insulated steam injection tubing for closing an annular space of the tubing which confines a vacuum. The plug is mounted for movement within a first mounting element and for movement within a bellows having an end connected to the first mounting element. A second mounting element is connected to the opposite end of the bellows and carries a rod which is fixed to the plug. By moving the two mounting elements together, the bellows is compressed and the plug is thrust by movement of the rod. The first mounting element is connected to an upper clamping section which cooperates with a lower clamping section to engage around a tubular to be plugged. The upper section can be correctly centered with its plug over the port of the tubular by momentarily compressing the bellows to extend the plug. The plug is provided with a shank portion and a breakable tab for breaking the plug away from the shank portion.

Abstract: An electronic integrator for integrating a linear voltage signal utilizes a voltage-to-frequency converter for converting the voltage to input frequency. A binary counter counts pulses of the input frequency. The binary counter generates a first operating frequency which is applied to a scaling circuit and another calibration frequency which has a much higher rate than the operating frequency. Both, however are proportional to the input frequency. The scaling circuit scales the operating frequency to a selected extent to form a counting signal. Using the double pole switch, either the calibration frequency or the counting frequency are applied to a pulse counter which is either used to integrate the input voltage signal by counting up pulses of the scaled counting signal, or the integrator can be calibrated using the calibration frequency which quickly increments the pulse counter.

Abstract: An on-line serial communication interface is established from a digital circuit such as a computer or hand held terminal, to a current loop which has lines for connecting a transmitter to a power supply. The interface includes a diode which is connected in series with one of the lines of the current loop. The diode is connected in parallel to the source and drain of a FET. The control gate of the FET is connected to the output of a differential amplifier who receives as one of its inputs, a digital voltage pulse signal from the digital circuit. The other input of the amplifier is held at a selected voltage so that voltage pulses are output from the amplifier when the digital circuit generates its voltage pulses. This turns the FET on and off in synchronism with the voltage pulses, thus cutting the diode in and out of series with the line of the current loop. With the FET in its non-conducting off condition, the diode has a small voltage drop thereacross. This does not effect the current on the current loop.

Abstract: A one-piece clip defines a receptacle for receiving a ribbon cable connector. Spring 10 tabs are provided at ends of the clip for permitting insertion and retention of the clip within a rectangular slot of a panel. The cable connector is insertable into the receptacle of the clip and the clip is insertable into the back panel by hand and without the need for any tools.

Abstract: A roll-and-race pulverizer is disclosed in which the throat vanes are mounted for rotation in the direction of rotation of the grinding ring.

Abstract: Angle-beam ultrasonic shear-waves, which are introduced via a pitch-catch technique in the axial and circumferential directions of a boiler tube, are used to detect the presence of hydrogen damage in boiler tubes.

Abstract: A system for the automatic and continuous determination of the efficiency of a fossil fuel-fired vapor generator for utilization by an automatic load control (88) to control the distribution of the system load among a plurality of generators, wherein various heat losses from various combustion sources are separately determined, the individual losses summed (80) and subtracted (86) from 100 percent to obtain a measure of the vapor generator efficiency.

Abstract: A vacuum sealing device includes a plug which is thrust into the port of an insulated steam injection tubing for closing an annular space of the tubing which confines a vacuum. The plug is mounted for movement within a first mounting element and for movement within a bellows having an end connected to the first mounting element. A second mounting element is connected to the opposite end of the bellows and carries a rod which is fixed to the plug. By moving the two mounting elements together, the bellows is compressed and the plug is thrust by movement of the rod. The first mounting element is connected to an upper clamping section which cooperates with a lower clamping section to engage around a tubular to be plugged. The upper section can be correctly centered with its plug over the port of the tubular by momentarily compressing the bellows to extend the plug. The plug is provided with a shank portion and a breakable tab for breaking the plug away from the shank portion.

Abstract: A sensor arrangement for a vortex shedding flowmeter having a flowmeter housing which is exposed to a flowing fluid in a fluid space on one side of the housing, comprises a sensor housing which is connected to the flowmeter housing and which defines an internal sensor space. A sensor beam is connected to the housing and has a first portion extending into the sensor space with a second portion extending through the flowmeter housing into the fluid space. A diaphragm resiliently carries the beam for movement in response to the passage of vortices in the fluid space. A mounting bracket is detachably connected to the sensor housing and carries a sensor element. The sensor element is operatively connected to the first portion of the sensor beam and can be easily engaged and disengaged thereto when the mounting bracket is to be removed. In this way if the sensor element fails, it can be replaced without stopping the flow of fluid or disturbing the sensor beam.

Abstract: A reflux condensing start-up system comprises a steam generator, a start-up vessel connected parallel to the steam generator, a main steam line connecting steam outlets of the steam generator and start-up vessel to a steam turbine, a condenser connected to an outlet of the turbine and a feedwater return line connected between the condenser and inlets of the steam generator and start-up vessel. The start-up vessel has one or more heaters at the bottom thereof for heating feedwater which is supplied over a start-up line to the start-up vessel. Steam is thus generated to pressurize the steam generator before the steam generator is supplied with a heat transfer medium, for example liquid sodium, in the case of a liquid metal fast breeder reactor. The start-up vessel includes upper and lower bulbs with a smaller diameter mid-section to act as water and steam reservoirs.

Abstract: A mechanism (10) engageable with a threaded shaft (12) which includes a pair of nut halves (16,18) movable into and out of engagement with the shaft (12). The nut halves (16,18) are received within spaced frame plates (32,34) with one nut half (16) attached to the plates (32,34) and the other nut half (18) slidable between the plates (32,34). An elliptical cam member (44) received between the slidable nut half (18) and an end plate (36) connecting the frame plates (32,34) is operable to move the nut halves (16,18) between their engaged and disengaged positions.

Abstract: A method and apparatus of obtaining a correction value for the deviation between an actual power usage and a desired target power usage during a time period, comprises dividing the time period into a plurality of time segments, measuring, after each time segment a fraction of time into each time period, and multiplying the fraction by the target power usage to obtain a value corresponding to the fraction of the total power usage during the cycle. Also after each time segment, the total amount of power which has actually been used is measured and a difference is taken between the total amount power used from the beginning of the period and the fraction of the target power usage from the beginning of the period. This value is then divided by the amount of time remaining in the cycle to obtain the correction value. The correction value can be processed and utilized to control an internal generator for the plant or to take other corrective action.

Abstract: A method is disclosed for ultrasonically detecting and measuring oxide scale on the inner cylindrical surface of a fluid containing boiler tube, in situ, within a boiler. An ultrasonic pulse is directed into the tube. The time of flight of the ultrasonic pulse within the scale is determined. The determined time is correlated to the thickness of the scale.

Abstract: A low power high efficiency switching power supply comprises a switching transducer having primary and secondary windings. The primary winding is supplied with a primary voltage over a series connected constant current source and Zener diode. The primary voltage is chopped by an FET which has a gate connected to an oscillator operating at relatively low frequency. The secondary windings of the transformer are connected to full-wave rectifiers which convert the A.C. signal produced by the chopping of the primary voltage, int a D.C. signal. Efficiency is maximized by using fast switching FET's and low flux densities in the transformer. The power supply is particularly useful in 4-20 mA current loops.