Abstract: An apparatus for measuring the relative flow of pulverized coal in a plurality of pipes connected between a common pulverizer and respective burners comprises a plurality of electric charge sensors each disposed in a similar position on the plurality of pipes. The electric sensors sense an induced signal produced by charged pulverized coal particles. For unbiased flow, the induced signal is proportional to the amount of flow in each pipe as the charge properties of the particles from the pulverizer are the same for all the pipes. A circuit is connected to the sensors for obtaining a root means square value of the induced signal which in turn is compared to each induced signal respectively to obtain a measurement of the relative flow in each pipe. The induced signal can be integrated twice to improve the correlation between flow and charge amount since the integrated value is independent of radial position for the charges in the pipes.

Abstract: A function generator producing an output signal varying in predetermined non-linear relationship to an input signal wherein the input signal addresses a programmable read-only memory (PROM) which is programmed to produce readout signals linearly proportional to selected values of the input signal and readout signals corresponding to the predetermined non-linear function of the input signal at said selected values and the output signal is derived by interpolation between the consecutive selected input signals which bracket the input signal.

Abstract: A device and method is disclosed which determines the presence and absence of a burner flame by injecting a pressure modulated signal into the burner which modulates a flame at a selected frequency. Light emitted from the flame is modulated at the same frequency. An optical sensor is provided for sensing the light amplitude modulation frequency and connected to a correlator circuit for correlating the light amplitude modulation signal with the pressure modulation signal. If the signals correlate, a flame is assumed to be present and a flame on signal generated. The pressure modulation signal can be discontinued periodically. If a corresponding discontinuation of the light amplitude modulation signal is sensed this is indicative of the continued presence of the flame whereas a continuation of the light amplitude modulation signal indicates a flame out condition.

Abstract: A dedicated correlator receives two noise signals from spaced centers sensing noise in a fluid flow. One of the noise signals in delayed by a variable known amount with respect to the other. The amount of correlation between the delayed and undelayed signal is determined. A sweep voltage generator is connected for variably increasing or decreasing the delay at set rates. A peak lock control is connected to the sweep generator and to the apparatus for establishing correlation for changing the direction of the sweep generator when it is determined that the amount of correlation is decreasing from a maximum. The particular delay amount corresponding to maximum correlation corresponds, in turn, to the amount of time required for the fluid to traverse the two sensors and, thus, the velocity of the fluid. The particular delay amount varies with variations in fluid velocity since the peak lock control follows these variations and controls the sweep voltage generator accordingly.

Abstract: Circuitry for extracting the square root of an incoming voltage signal is disclosed. The circuit (10) utilizes a four-bit up/down counter (14) to control the output duty cycle of a pair of four-bit rate multipliers (16, 18) connected in a cascaded configuration. The output of the second rate multiplier (18), which is related to the square of the up/down counter value, is used to control the mode of the counter (14) so as to track the incoming voltage signal. Inasmuch as the square of the up/down counter value is tracking the incoming voltage signal, the output duty cycle of the first rate multiplier (16) in the cascaded pair is the square root of the incoming voltage signal which is subsequently converted into analog form. The circuit also utilizes a "dithering" technique so that the resulting square root output signal has greater than four-bit accuracy.

Abstract: A circuit for processing the vortex shedding frequency signal of a vortex shedding flowmeter comprises a phase detector, switch and low pass filter connected in series. The phase detector receives the vortex shedding frequency and applies it over the normally closed switch to the low pass filter which produces an analog signal corresponding to the frequency of the vortex shedding frequency signal. A voltage controlled oscillator is connected between an output of the low pass filter and an input of the phase detector for tracking the vortex shedding frequency and producing a tracking frequency signal which is maintained when the vortex shedding frequency signal disappears. A range or gain code circuit portion is connected for establishing a set time period during which the frequency signal is accumulated in a counter. The accumulated signal from the counter is utilized as a digital signal corresponding to the vortex shedding frequency signal.

Abstract: A device is disclosed for measuring the mass and velocity of a fluid flowing in a conduit, in a flow direction, which comprises a pair of signal transducer arrays each disposed at planes extending through the conduit and spaced in the flow direction. Each transducer of each array is adapted to transmit a signal and receive all signals of all other transducers so that a variety of signal paths are established through the flow both transversely to the flow and in the flow direction. Differences in transit times between arrays are used to measure velocity and attenuation of the signal within an array are used to determine density. The density and velocity measurements are combined to determine mass flow.

Abstract: A notch filter arrangement for reducing vibration noise in a vortex shedding flowmeter circuit is disclosed which utilizes a plurality of sequentially closable switches. The plurality of switches are all closed during a single period of the vibration signal fundamental frequency. Each switch is connected in series to a capacitor which is connected to the output signal of a vortex sensor so that the instantaneous average voltage of the vibration signal during any increment of time is subtracted from the vortex shedding frequency signal to produce a noise reduced signal.

Abstract: A circuit for a vortex shedding flowmeter is disclosed which generates an analog signal proportional to the vortex shedding frequency and a pulse signal which equals or is proportional to the vortex shedding frequency signal. A scaling or range selection counter can be provided between the pulse signal and an output stage for changing the effective range of measurement by dividing the shedding frequency by a selected and known number.

Abstract: A hybrid analog function generator producing an adjustable time delayed analog output signal varying in predetermined non-linear relationship with an analog input signal wherein the analog input signal is converted to a first digital signal addressing a programmable read only memory which is programmed to produce a second digital signal, corresponding to the predetermined function of the analog input signal, which is converted to a proportional analog output signal and wherein a selected digital number can be added to the first digital signal and wherein the quotient of a first analog input signal divided by a second analog input signal can be converted to the first digital signal and wherein an analog output signal can be generated which is proportional to the second digital signal multiplied by a third analog input signal.

Abstract: A voltage linearization circuit for use with a resistance thermometer device or a thermocouple to produce a nearly linear output signal from a non-linear input signal. The circuit produces a voltage proportional to the square of the input voltage through the use of operational amplifiers and field-effect transistors connected in voltage dividing arrangements, and combines this second order voltage, or a reduced magnitude thereof, with the original input voltage to produce a nearly linear output signal.