Abstract: An ultrasonic echo-ranging meter for measuring the changing level of liquid in a tank or open channel, the meter including a transducer at a raised position above the liquid surface. Pulses of ultrasonic energy transmitted by the transducer are directed toward the liquid surface and reflected thereby to produce main echo pulses that are picked up by the same transducer. The round trip transmit time of the pulse energy in the gaseous medium above the liquid depends on the distance between the transducer and the liquid surface, this time being measured to provide a reading of liquid level. Also intercepted by the transducer are parasitic echo pulses originating from reflecting wall surfaces and other obstacles in the vicinity of the tank or channel, which parasitic pulses may be confused with the main echo pulses and result in an erroneous reading.

Abstract: A telemetering system wherein a transmitting device responsive to an input signal derived from a sensor representing a metered variable, such as temperature or flow rate, is adapted to generate a corresponding direct-current signal. This signal is conveyed over a two-wire line to a receiving station through a terminal resistor across which a voltage signal is developed corresponding to the incoming current signal. The receiving station includes a DC power supply whose output is fed over the same two-wire line to the transmitting device to provide operating power therefor. In order to enhance the power available to the transmitting device, the current signal generated by the transmitting device lies in a 0% to 100% signal range in which the ratio of direct-current I.sub.o at 0% signal to direct-current I.sub.100 at 100% signal is greater than 1/5 or 0.2.

Abstract: A magnetic flowmeter in which a fluid to be metered is conducted through a ceramic spool coaxially supported within a cylinder casing to define an inner chamber. Mounted within the chamber at opposing positions on a magnet axis perpendicular to the longitudinal flow axis of the spool are a pair of electromagnets to establish an electromagnetic field in the spool whose lines of flux are intercepted by the fluid to induce a voltage therein. Interposed between the electromagnets and the outer surface of the spool and conforming to and secured to this surface are a pair of flexible printed circuit boards which are so printed as to define capacitance metering electrodes at diametrically-opposed positions on the spool on an electrode axis at right angles to the magnet axis and at right angles to the longitudinal flow axis, whereby the voltage induced in the fluid is picked up by these electrodes to produce a signal which depends on the flow rate of the fluid.

Abstract: An electromagnetic flowmeter having a frame assembly formed by an octagonal metal frame within which are mounted a pair of electromagnets and a pair of electrode holders. The electromagnets are secured to one set of opposing sides of the frame along a first transverse axis which passes through the geometric center of the frame while the holders are secured to another set of opposing sides along a second tranverse axis which passes through the center at right angles to the first axis. The frame assembly is encapsulated within a generally cylindrical plastic insulating body of polymeric material having a longitudinal bore therein defining a flow conduit whose flow axis passes through the geometric center of the frame and is perpendicular both to the first and second transverse axes whereby when the fluid flows therethrough it intersects the magnetic lines of flux produced by the electromagnets.

Abstract: A mass flowmeter of the Coriolis-type in which the fluid to be metered is conducted through a loop supported on a stationary frame, the loop having a natural resonance frequency. Mounted at the vertex of the loop is a ballistic vibrator which is electrically energized to cause the loop to vibrate at its natural frequency on either side of its static plane. The fluid passing through the loop is subjected to Coriolis forces, causing the vibrating loop to torsionally oscillate in accordance with the mass flow rate of the fluid. This torsional oscillation is sensed by a pair of strain gauge transducers mounted in balanced relation on opposite legs of the loop, whereby the signals yielded by the transducers have a difference in magnitude therebetween that depends on the amplitude of the torsional oscillation. These signals are applied to a differential amplifier whose output is proportional to the mass flow rate of the fluid.

Abstract: A mass flowmeter of the Coriolis type in which the fluid to be metered is conducted through a pipe which is coiled to form a double loop. The pipe is anchored at its inlet and outlet ends and also at its center which is the junction of the two loops to define a tuning fork in which the identical loops on either side of the anchored center function as tines that are free to vibrate as well as to twist. An electromagnetic driver mounted at the vertex of the double loop is electrically energized to cause the loops to vibrate in phase opposition at the natural frequency of the tuning fork. The fluid passing through the double loop is subjected to Coriolis forces, thereby causing the vibrating loops to torsionally oscillate in accordance with the mass flow of the fluid.

Abstract: A front display panel for an industrial process control instrument which acts to maintain a process variable, such as flow rate, at a desired value. The instrument compares a signal representing the variable with an adjustable set point to produce an output signal that reflects the deviation of the variable from the set point, the output signal being applied to a final control element such as a valve which governs the process variable. The front panel of the instrument includes a bar graph indicator for the process variable, a bar graph indicator for the set point and a bar graph indicator for the output signal, all three indicators being of the gas discharge type and being integrated into a single panel defining a sealed envelope filled with an ionizable gas and provided with electrodes. Also integrated into the panel are touch-sensitive switches and other control and indicating elements.

Abstract: An electromagnetic flowmeter in which the fluid being metered is conducted through a flow tube having a pair of electrodes, the fluid intersecting a magnetic field whereby the resultant voltage induced in the fluid is transferred to the electrodes to provide a signal indicative to flow rate. The magnetic field is created by a pair of pole pieces formed of "hard" magnetic material. The pieces are placed at diametrically-opposed positions and are magnetically interconnected to define a magnetic circuit. Excitation pulses which alternate in polarity are periodically applied by respective magnet drivers to coils wound about the pole pieces to alternately magnetize the pieces in one direction and remagnetize the pieces in the reverse direction, thereby establishing the desired field. The duty cycle of the pulses is such as to reduce the average power requirements to a very low level.

Abstract: A magnetic flowmeter which includes a spool formed by a metallizable ceramic whose dielectric constant is at least 25 through which the fluid to be metered is conducted. The outer surface of the spool is metallized in its central region to define a pair of capacitative metering electrodes at diametrically-opposed positions, an electromagnetic field being established within the spool whereby when the flowing fluid intercepts this field, an emf is induced therein to produce a signal at the metering electrodes which is a function of flow rate. Overlying each metering electrode and projecting from the spool is a ceramic block whose outer surface is metallized to define a shield electrode which covers the metering electrode.

Abstract: A highly compact electromagnetic flowmeter unit interposable between the flanged ends of upstream and downstream line pipes for metering fluid passing through the line. The flowmeter is constituted by a cylindrical casing of ferromagnetic material within which a pair of electromagnet coils is supported at opposed positions along a diametrical axis normal to the longitudinal axis of the casing, the longitudinal axis passing through the central flow passage of an annular pressure vessel. The vessel, which is formed of high-strength insulating epoxy material, is molded within the casing and encapsulates the coils as well as a pair of pre-cast electrodes formed of conductive epoxy material disposed at diametrically-opposed positions with respect to the flow passage along a transverse axis at right angles to the coil axis to define a unitary structure. The epoxy of the electrodes is compatible with that of the vessel, whereby a fluid-impermeable bond is formed therebetween.

Abstract: An electromagnetic flowmeter wherein a liquid to be metered is conducted through the flow tube of a primary to intersect a transverse magnetic field produced by an electromagnet. The resultant signal induced in the liquid is transferred to a pair of electrodes mounted at diametrically-opposed points on the tube. To avoid spurious signal components arising from stray couplings between the electromagnet and the loop constituted by the electrodes and the liquid bridging the electrodes, the coil of the electromagnet is energized by a low-frequency wave whose frequency is well below that of the standard a-c power line.

Abstract: An analog-to-digital converter for an electromagnetic flowmeter in which the fluid being metered passes through a flow tube to intersect a magnetic field, the voltage induced in the fluid being transferred to a pair of electrodes. The magnetic field is established by an electromagnet supplied with excitation current that is alternately turned "on" and "off" at a low frequency rate. The resultant flow-induced electrode signal is sampled for a predetermined interval in each "on" and "off" field state, successive differences therebetween serving to develop an analog signal representing the flow rate. Conversion is effected by integrating each sample to produce a sloped voltage whose polarity corresponds to that of the sample and whose peak level relative to a base level is determined by the amplitude of the sample, the sloped voltage being then de-integrated back to base level in a time slot whose duration is directly proportional to the average level of the sample.

Abstract: An in-line contactor adapted to bring about intimate contact between a disinfectant and a wastewater stream to produce a reaction between the disinfectant and pathogens effecting kills in a manner minimizing unwanted side effects. The wastewater stream is pumped through the successive stages of the contactor, the first of which is an input section having a converging nozzle that projects the stream at high velocity into a throat. The throat feeds the stream in a highly turbulent state through a mixing section, the resultant vacuum created within the throat acting to draw a disinfectant such as aqueous or gaseous chlorine from a disinfectant supply into the mixing section where it is thoroughly intermingled with the turbulent stream before the stream is discharged from the contactor through a diverging pressure-recovery output section.

Abstract: An electromagnetic flowmeter which includes a flow tube through which the fluid to be metered is conducted, the fluid intercepting a magnetic field to induce a voltage therein which is transferred to a pair of electrodes mounted at diametrically opposed positions on the tube. The inside surface of the meter tube is protectively lined with a stable liner assembly constituted by a three-dimensional stiffening structure embedded in an insulating layer which conforms to the surface.

Abstract: A vortex-shedding flowmeter capable of accurately measuring the flow rate of a liquid or gas even under extreme operating conditions. The fluid to be metered is conducted though a flow pipe having a shedder fixedly mounted therein. A sensor which is caused to oscillate at a rate proportionate to the flow rate of the fluid is torsionally supported downstream behind the shedder on a pivot axis normal to the flow axis of the pipe, the torsional support including a torque tube whose base is received within a bore in the pipe and is welded thereto and whose tip is welded to one end of the sensor to provide a closed structure preventing leakage of fluid from the pipe. The sensor oscillations are converted into corresponding electrical signals by an external torque transducer operatively coupled to the sensor by a sensor link assembly including a rod which extends coaxially into the torque tube and is welded to the tip thereof.

Abstract: A disinfectant system for intermingling a disinfectant with an effluent to be treated, such as wastewater, to kill pathogens therein, the system enhancing contact between the effluent and the disinfectant to effect a rapid and efficient disinfection action. The system includes an ejector through which a minor portion of the effluent is pumped to produce a motive fluid which induces a disinfectant therein to produce a concentrated disinfectant fluid. Th ejector terminates in a cylindrical diffuser section having a closed end and at least two circumferential series of orifices whereby the disinfectant fluid is discharged therefrom as high velocity jets which project radially with respect to the longitudinal axis of the section.

Abstract: A magnetic flowmeter which generates a signal proportional to the flow rate of a fluid passing through a pipe to intersect a magnetic field whose lines of flux are substantially parallel to a transverse axis normal to the longitudinal axis of the pipe. The flowmeter includes two electrode assemblies mounted on the pipe on opposite sides of the transverse axis and capacitively coupled to the fluid. The effective coupling capacity of the electrodes in each assembly is such as to render the signal substantially immune to the influence of non-axisymmetric flow profiles.

Abstract: A dual output vortex-shedding flowmeter in which a liquid or gas to be metered is conducted through a flow tube having a shedding body transversely supported thereon, the flowmeter being usable in a custody transfer system requiring two independent output signals. Torsionally-supported behind the body and spaced therefrom by a gap is a drag-actuated sensor which includes a pair of parallel legs symmetrically disposed with respect to a spindle forming the fulcrum axis of the sensor, this axis being normal to the longitudinal axis of the tube. In operation, torques are developed alternately in the clockwise and counterclockwise directions, causing the torsionally-supported sensor to oscillate at a frequency proportional to the flow rate of the fluid. These oscillations are converted into corresponding electrical signals by a pair of transducers coupled to opposing ends of the spindle to provide two independent outputs.

Abstract: A stabilized vortex-shedding flowmeter for accurately measuring the flow rate of a liquid or gas conducted through a flow tube. The meter includes a front obstacle transversely mounted across the tube with its longitudinal axis normal to the flow axis of the tube. Supported behind the front obstacle and spaced therefrom by a gap is a rear obstacle constituted by a pair of parallel beams symmetrically disposed with respect to the flow axis and lying in a plane normal thereto. In operation, as the incoming fluid stream is divided by and flows past the front obstacle, a stagnant zone is created in the gap. This zone is initially aligned with the flow axis; but as vortices are successively detached from the front obstacle and appear alternately on either side of the gap, the low pressure produced by each vortex act to draw the stagnant zone in front of the beam adjacent thereto, the fluid then going around and past the other beam and imposing a drag force thereon.

Abstract: An electromagnetic flowmeter wherein a liquid to be metered is conducted through a flow tube to intersect a transverse magnetic field produced by an electromagnet, the resultant signal induced in the liquid being transferred to a pair of electrodes mounted at diametrically-opposed points on the tube. To avoid spurious signal components arising from stray couplings between the electromagnet and the loop constituted by the electrodes and the liquid bridging the electrodes, the coil of the electromagnet is energized by a low-frequency wave whose frequency is well below the standard a-c power line frequency. And, to avoid noise components produced when the liquid being metered is a slurry containing solid particles which impinge on the surface of the electrodes, the electrodes are fabricated of or coated by a carbide metal or an alloy thereof whose metallurgical hardness is such as to substantially reduce the generation of such noise components.