Abstract: A thermal flow sensor of a switching control type for measuring the flow rate of intake air of an internal combustion engine comprises a bridge circuit including temperature sensing resistors, a differential amplification circuit, a pulse generating circuit, a power supply control circuit and a resonance preventing circuit. The amplification circuit amplifying the output from the bridge circuit. The pulse generating circuit receives the output from the amplification circuit and generates a pulse train which has a time ratio corresponding to the output level of the amplification circuit. The power supply control means comprises a switching transistor which is turned on and off by the pulse train from the pulse generating circuit and a smoothing circuit which makes the output from the transistor continuous and supplies the continuous voltage to the bridge circuit.

Abstract: A digital image preprocessing method for eliminating background patterns and scenes from digitized gray level document image data. The method accepts multi-gray level image data as input and produces a gray level output image containing a "white" background. Document image backgrounds are eliminated (or suppressed) by computing a separate (and typically different) threshold value for each gray level pixel of the original document image. Input image pixels whose gray level is greater (brighter) than the threshold value are assumed to be background picture data and are modified to be "white" pixels in the output image. The pixel threshold value is determined dynamically pixel-to-pixel based on gray level pixel data observed within the input image. Additionally, the pixel threshold can be automatically controlled to insure retention of written and/or printed information present in the input image.

Abstract: In an image scanning device having a scanning array with a plurality of photosites detecting light from an image, the signals from the photosites being output from the scanning array through an amplifier in a sequence having reset pulses between the analog signals for each photosite, an apparatus maintains the reset pulses at a constant offset voltage. A peak follower holds the maximum value of voltage from each cycle of the sequence as the offset voltage, and outputs a constant voltage related to the offset voltage. An amplifier return driver accepts the constant voltage from the peak follower, and maintains the potential between the signal input to the amplifier and the return of the amplifier at a constant value.

Abstract: An acoustic signal is transmitted into a flowing gas (10). The velocities of propagation of the signal in two predetermined directions are measured, and combined with sensed gas pressure and the frequency of the acoustic signal to compute the mass flow rate of the gas. The velocities are preferably measured as analogous phase differences between the transmitted signal, and the signal as incident upon receivers (18,20) spaced from the signal transmitter (16) by predetermined distances in the predetermined directions. The phase differences are preferably sensed using at least one phase locked loop (44) which adjusts the signal frequency so that a predetermined phase difference is maintained between the transmitted signal and one of the received signals or a derivative thereof. The flow rate computation includes obtaining the speed of the acoustic signal (speed of sound) in the material and the velocity of movement of the gas from the sensed phase differences.

Abstract: A flowmeter has a vortex generating bluff body (102) disposed across the flow passage (106), a planar member (103) disposed immediate upstream of the bluff body (102) including a plurality of total pressure ports emerging through the leading edge of the planar member (103) and a plurality of static pressure ports emerging through the side faces of the planar member (103), and a vortex sensing device including a planar member (104) and one or two transducers (111 and 112), which flowmeter determines the mass and volume flow rates of the fluid and the density of the fluid from the dynamic pressure determined from the difference between the total and static pressures and the fluid velocity determined from the vortex shedding frequency.

Abstract: An apparatus for measuring the mass flow rate of air has a resistance bridge circuit, whose diagonal voltage is applied to a switching control element, which is in turn supplied with voltage pulses for heating a flow sensor probe. The switching control element regulates the heat output conveyed to the probe, and emits an output signal proportional to the mass flow rate of air over the probe. The voltage pulses (U.sub.T) for heating the probe are supplied to a first closed loop control circuit. The first closed loop control circuit emits a first output signal (U.sub.a1), which is a function of the voltage measured across the diagonals of the resistance bridge circuit. A second closed loop control circuit is adapted to receive the first output signal (U.sub.a1) and an input signal (V.sub.2 U.sub.R). The input signal (v.sub.2 U.sub.R) depends on the voltage pulses (U.sub.T) for heating the sensor's probe, a reference variable (U.sub.R), and the first output signal (U.sub.a1).

Abstract: A positive displacement apparatus usable as a pump or motor or flowmeter comprises a first revolving vane rotatably disposed in a first cylindrical cavity wherein the edge of the first revolving vane sweeps on a circular cylindrical portion of the cylindrical wall of the first cylindrical cavity, and a second revolving vane rotatably disposed in a second cylindrical cavity wherein the edge of the second revolving vane sweeps on a circular cylindrical portion of the cylindrical wall of the second cylindrical cavity, wherein the rotating motions of the first and second revolving vanes are coupled to one another in such a way that the edge of at least one of the first and second revolving vanes sweeps on respective circular cylindrical portions of the cylindrical walls of the respective cylindrical cavities at all instances, whereby a fluid moving through the first and second cylindrical cavities providing a flow passage in series results in a rotating motion of the revolving vanes and vice versa.

Abstract: A vortex flowmeter is provided with a vortex-inducing bluff body in the form of a first, upstream, cylinder having a semi-circular or semi-ellipsoidal front surface and a planar rear surface, and a second, downstream, cylinder having a planar front surface and a planar or concave rear surface. The rear surface of the upstream cylinder is parallel to the front surface of the downstream cylinder, and separated from it by a gap whose width is preferably about 25% of the diameter of the upstream cylinder.

Abstract: In a heat-sensitive flow sensor including a bridge circuit composed of a heat-sensitive resistor formed on a substrate provided within a fluid flow passage and a plurality of resistors and a control circuit for controlling current supplied to the heat-sensitive resistor to maintain the bridge circuit in a thermally balanced condition, a flow rate being detected from the thermal balance condition of the bridge circuit, current supply leads and a base portion of the substrate are buried in a heat insulating support member supported by a base. Preferably, lead terminals of the heat-sensitive resistor formed on the base portion are also buried in the heat insulating support member.

Abstract: A turbine flowmeter includes an impeller rotatably provided within a flow passage through which a fluid to be measured flows and comprising a rotary shaft which rotates together with the impeller, a pair of bearing part having bearing surfaces for axially supporting the rotary shaft, a holding part for holding the bearing part and provided on the flow passage, an oil accumulating space defined by an end portion of the rotary shaft and bearing surfaces facing respective sides of the end portion, an oil accumulating part provided on the holding part and filled with the lubricating oil to be supplied to the oil accumulating space, an oil supplying part for supplying oil to the oil accumulating space which part comprises a capillary part connected on one end direct to the oil accumulating part and communicated on the other end to the space, wherein the lubricating oil is supplied to the space via the oil supplying part from the oil accumulating part by capillarity introduced in the oil accumulating part and the s

Abstract: A gas flowmeter which is disposed between adjacent sections of a gas piping includes a central elongate housing. This housing includes a central gas passage, a plurality of sensor modules arranged in a row adjacent the central passage, and a distribution strip arranged along the sensor modules to conduct measuring signals therefrom. A plurality of electronic processing units are mounted about the elongate housing and in electrical contact with the distribution strip to process the signals from the modules and to then produce processed signals. These processing units are shell shaped with an open longitudinal side so as to fit onto and about a corresponding portion of the elongate housing. With this construction, a compact, lightweight and easy to repair gas flowmeter is provided.

Abstract: A constant temperature gradient fluid mass flow transducer is described. The upstream and downstream ends of a measuring section of a capillary tube of the transducer are held at respective constant temperatures by separate temperature regulated heat sinks, the downstream end being hotter. A heat conducting outer tube surrounds the measuring section and joins the heat sinks to cause the measuring section temperature to assume a substantially linear profile at a constant gradient. An electrical heater supplies heat uniformly to the measuring section to replace that transferred to the flowing fluid within the capillary tube and thereby keep the temperature and gradient constant. The voltage across the heater, proportional to the square root of mass flow rate, is taken as the output signal.

Abstract: An arrangement for measuring a quantity of intake air passing through an intake air duct by a sensing element disposed in parallel with a flow direction of the intake air. The sensing element includes a flow speed sensing resistor deposited on a base plate and formed into a film for sensing a flow speed of the intake air, and a pair of lead members deposited on the base plate and electrically connected to the resistor. The flow speed sensing resistor is arranged to form a temperature distribution of the resistor uniform in a direction parallel with and/or perpendicular to the flow direction of the intake air.

Abstract: An apparatus for measuring the rates of flow of fluid through a line, which is characterized by a fluid driven turbine whose axis may be pivotably varied throughout an arc from being parallel to the direction of fluid flow to a position perpendicular to the direction of fluid flow. By varying the angle at which the fluid flow impinges on the turbine wheel the "K factor", that is the rate of turbine rotation per unit of fluid flow can be adjusted so as to adapt the flowmeter to differing fluids (such as, steam, air and other gaseous fluids, and, both low and high density liquids). Also, by varying the angle at which the fluid flow impinges on the turbine wheel the rate of turbine rotation per unit of fluid flow can be adjusted to adapt the flowmeter to a very wide range of flow rates (high rangeability).

Abstract: A flow rate measuring apparatus includes a measuring pipe in which a fluid to be measured flows, a flowmeter for measuring a flow rate of the fluid to be measured flowing in the measuring pipe, and a cleaning flow generator for removing an adhesive substance in the measuring pipe by using the fluid to be measured, thereby correctly performing flow rate measurement by the measuring pipe. When the flowmeter is an electromagnetic flowmeter, the cleaning flow generator prevents the adhesive substance from resistively connecting electrodes for induced electromotive force detection. When the flowmeter is an ultrasonic flowmeter, the cleaning flow generator prevents the adhesive substance from interfering with transmission of an ultrasonic wave in the measuring pipe.

Abstract: A flow sensing apparatus has an obstruction extending across the tube to form two openings. The obstruction is at an angle to the tube axis and includes a portion with reduced dimension. Pressure sensors are located on opposite sides of the obstruction.

Abstract: A mass flowmeter comprises a conduit with two end sections respectively extending from the two secured extremities of the conduit and connected to one another by a curved midsection of the conduit, an electromagnetic vibrator vibrating the two opposite halves of the conduit relative to one another in directions generally parallel to a plane including the curved midsection of the conduit, and a pair of motion sensors respectively measuring flexural vibrations of the two opposite halves of the conduit; wherein mass flow rate of media moving through the conduit is determined from the phase angle difference between two flexural vibrations respectively measured by the two motion sensors.

Abstract: An apparatus for generating and/or measuring fluid flow and/or generating power from fluid flow comprises two combinations of a cylindrical cavity and a divider member rotatably disposed in the cylindrical cavity about an axis of rotation parallel and eccentric to the geometrical central axis of the cylindrical cavity, which divider member extends across the cylindrical cavity on a plane including the axis of rotation in all instances of rotating movement thereof, and a rotary motion coupling means coupling rotating motions of the two divider members in such a way that a phase angle difference of ninety degrees in the rotating motion between the two divider members is maintained, wherein fluid moving through the two cylindrical cavities and crossing each plane including the geometrical central axis and the axis of rotation in each of the two cylindrical cavities relates to rotating motion of the two divider members.

Abstract: A mass flow meter for flowing media, which operates on the Coriolis Principle, has a conduit inlet, a conduit for carrying a flow medium, a conduit outlet, a carrier system carrying the conduit, the conduit inlet and the conduit outlet, at least one oscillator acting on the conduit and at least one measuring device detecting Coriolis oscillation based on a Coriolis force or forces. The mass flow meter is especially appropriate for technical manufacturing, measuring and operating requirements because the conduit is designed in a meandering form and has an inlet bend, at least two return bends, an outlet bend and connecting pieces in between.

Abstract: The bobbin (21) of the heating resistor (1) is made by zirconia or glass fiber. On the surface of the bobbin, a platinum film (31) or a platimum wire (23) are formed. At both ends of the heating resistor, the heating resistor is supported by a pair of supporting conductors (25).