Abstract: A pneumatic relay responsive to an air input signal whose pressure represents a variable, the relay producing an air output signal proportional thereto. The relay includes an input chamber to which the input signal is fed, this chamber being separated from an output chamber by a diaphragm of elastomeric material. Air from a constant high-pressure supply is fed into the output chamber through an adjustable supply port that is operatively coupled to the diaphragm to cause this port to open to an extent determined by the deflection of the diaphragm in response to the force produced by the pressure of air in the input chamber until a point is reached where the pressure developed in the output chamber attains equilibrium with that in the input chamber.

Abstract: A transmission system for a vortex-shedding or swirl-type flowmeter whose meter signal lies in the low-frequency range and is therefore of low resolution, the meter signal being subject to jitter. In order to provide a jitter-free, high resolution output signal, the system includes an input amplifier responsive to the meter signal, the output of which is applied through a tracking filter to a Schmitt trigger. The trigger converts the meter signal into pulses of the same frequency which are fed into a frequency multiplier to produce a relatively high-frequency output signal of good resolution. The tracking filter serves to characterize the amplifier response to reduce the amplification gain thereof below a selected frequency level. The tracking filter operates in conjunction with a comparator assembly which compares an analog voltage whose magnitude depends on the meter signal frequency with a series of progressively increased reference voltages, each representing a predetermined frequency level.

Abstract: A 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. Torsionally-supported at a downstream position behind the shedder on a shaft which projects outside of the flow tube to provide a shaft extension is a sensor, the pivot axis of the shaft being normal to the longitudinal axis of the tube. In operation, as the incoming fluid stream is divided by and flows past the shedder, vortices are successively detached therefrom and appear alternately on either side of the sensor, thereby developing a torque about the pivot axis. The torques are developed alternately in the clockwise and counterclockwise directions, causing the torsionally-supported sensor to oscillate at a rate proportional to the flow rate of the fluid. These oscillations are converted by a transducer operatively coupled to the sensor into a corresponding electrical signal.

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 unit being subject to compression by these flanged ends to effect a fluid seal. The flowmeter is constituted by a non-magnetic metal spool of high strength whose inner surface is lined with insulating material to provide a flow conduit for the fluid to be metered, the spool also serving to withstand the compressive forces to which the unit is subjected as well as the fluid pressure. Surrounding the spool and concentric therewith is a cylindrical housing fabricated of ferromagnetic material, the housing being preferably formed by complementary half-pieces which are interconnected and include end plates which join the corresponding ends of the spool to define an inner chamber.

Abstract: An electromagnetic flowmeter having a flow tube provided with a pair of diametrically-opposed electrodes, the fluid to be metered passing through the tube to intercept a magnetic field thereon, thereby inducing a signal at the electrodes which is a function of flow rate. In this arrangement, X is the axis connecting the electrodes, Z is the axis of the tube and Y is an axis mutually perpendicular to the X and Z axes. In order to minimize the adverse effect of disturbances in flow profile on the flow-induced signal, an electromagnetic field is established by an electromagnet assembly formed by two pairs of electromagnets, each pair being disposed at diametrically-opposed positions on the tube exterior to produce a magnetic field whose lines of flux are substantially parallel to the Y axis, the two paris being symmetrically disposed on either side of the X-Y electrode plane to create a combined magnetic field having a B.sub.

Abstract: An electromagnetic flowmeter in which the fluid to be metered is conducted through a flow tube provided with a pair of diametrically-opposed electrodes. The fluid intercepts a magnetic field established in the flow tube by a magnetizable core having a coil wound thereon through which an excitation current flows, thereby inducing a signal voltage in the electrodes. Because the permeability of the core is temperature-dependent, changes in temperature affect the strength of the magnetic field and adversely influence the signal voltage. Compensation means are provided to render the signal voltage independent of temperature, thereby producing an output signal accurately proportional to flow rate.

Abstract: A gravity flow disinfectant contactor adapted to enhance contact between a disinfectant solution such as chlorine and the water to be treated to effect a more rapid and efficient disinfection activity. The contactor is constituted by a rectangular conduit having a cross-sectional diffusion plane adjacent its inlet within which is an array of evenly-spaced diffuser tubes supplied with the disinfectant solution. The tubes each have a row of equi-spaced holes drilled diametrically therethrough to produce side-by-side opposing jets of disinfectant in the diffusion plane at right angles to the cross-flowing water stream. As a consequence, the water flowing through the conduit is subjected to a dense cross fire of multiple jets of disinfectant that are uniformly distributed throughout the diffusion plane and quickly interact with the water within a relatively short downstream distance.

Abstract: A 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. 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 the fulcrum axis of the sensor, this axis being normal to the longitudinal axis of the tube. In operation, as the incoming fluid stream is divided by and flows past the shedding body, it creates a stagnant zone in the gap that is initially aligned with the tube axis. But as vortices are successively detached from the body and appear alternately on either side of the gap, the low pressure region produced by each vortex acts to draw the stagnant zone in front of the adjacent leg of the sensor, the fluid flow then going around and past the other leg, thereby developing a torque about the fulcrum axis.

Abstract: A flangeless electromagnetic flowmeter insertable between upstream and downstream pipes which have the same internal diameter, the adjacent ends of said pipes having like flanges. The cylindrical body of the flowmeter is interposed between the flanged ends of the pipes, the body being provided with an annular pressure vessel formed of insulating material to define a central flow passage whose diameter matches the internal diameter of the pipe whereby the flowmeter functions to meter the flow rate of fluid passing through the pipes and the passage along a longitudinal axis extending therethrough. A pair of electromagnetic coils is embedded in the vessel at opposed positions with respect to the passage to establish a magnetic field therein whose lines of flux are substantially perpendicular to the longitudinal axis.

Abstract: A drive system for an electromagnetic flowmeter wherein the fluid to be metered is conducted through a flow tube to intersect a transverse magnetic field created by an electromagnet having an excitation coil. The resultant voltage induced in the fluid is transferred to a pair of electrodes mounted at diametrically-opposed points on the tube to yield a signal representing flow rate. The drive system, which is powered from an a-c line, includes a full-wave rectifier whose output voltage is applied periodically to the excitation coil at a rate which is low relative to the line frequency.

Abstract: An electromagnetic flowmeter in which a fluid to be metered is conducted through a flow tube formed of a non-magnetizable, weldable metal pipe having an insulating liner therein and provided with a pair of diametrically-opposed electrodes. The fluid passing through the tube intercepts a magnetic field to induce a signal in the electrodes indicative of flow rate. The magnetic field is established by a magnet system excited by a low-frequency alternating or pulsating current, the system including at least one solid core of ferromagnetic material about which is wound an excitation coil. The core has its inner face welded to the outer surface of the pipe to provide a highly stable magnet system.

Abstract: A vortex-shedding flowmeter in which a shedder is transversely mounted in a flow tube through which the fluid to be metered is conducted, the shedder dividing the flow and causing vortices to be shed alternately on either side thereof at a repetition rate proportional to flow rate, thereby producing downstream trains of vortices moving along the right and left sides of the tube. The wave span between the eyes of successive vortices in the trains has a substantially constant length determined by the geometry of the shedder. At a downstream position in the flow tube is a vane flanked by the trains of vortices and having a length no less than one-half the length of the span and no greater than the full length thereof. The vane is pivoted on a torsion shaft on its central axis which is perpendicular to the tube axis and is balanced with respect thereto.

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 ferromagnetic ring within which a pair of electromagnet coils is supported at opposed positions along a diametrical axis normal to the longitudinal axis of the ring, the longitudinal axis passing through the central flow passage of an annular pressure vessel. The vessel, which is formed of high-strength insulating material, is molded within the ring and encapsulates the coils as well as a pair of electrodes 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 unit is compressible between the end flanges of the pipes by bridging bolts that pass through bore holes in the pressure vessel or lie outside the ring to encage the unit.

Abstract: A system adapted to continuously and accurately measure the concentration of chlorine dioxide dissolved in liquid, the system including a sensor immersible in the liquid being tested. The sensor is constituted by a noble-metal measuring electrode, an oxidizable-metal counter electrode and an electrolyte which together define an electrochemical cell whose output current depends on the amount of chlorine dioxide passing into the cell through a diffusion membrane permeable to chlorine dioxide but not to the liquid. The chlorine dioxide within the cell is electrochemically reduced at the surface of the measuring electrode to generate a current proportional to its concentration, the counter-electrode being oxidized to complete the cell reaction.

Abstract: An analyzer for continuously and accurately measuring the hypochlorous acid content of chlorinated water containing free available chlorine having a hypochlorous acid component (HOCl) which is a highly reactive disinfectant and a less reactive hypochlorite ion component (OCl.sup.-). To make this determination, a sample of the chlorinated water is sensed by three probes--one yielding an analog signal representing the free available chlorine content (FAC) of the sample; the second, an analog signal representing the pH of the sample; the third, an analog signal representing the sample temperature (T). These signals are digitized and applied as input data to a digital computer wherein the percentage of HOCl in the sample at a reference temperature is established on the basis of the pH data by consulting a memory storing the relationship between the percentages of HOCl and OCl.sup.- in a range of pH values.

Abstract: An electromagnetic flowmeter capable of accurately measuring the flow rate of fluid conveyed on a line in either direction. The flowmeter includes a primary whose flow tube is provided with electrodes yielding a signal depending on the flow rate of the fluid intersecting a magnetic field established in the tube, the sense of the signal changing with the direction of flow. This electrode signal is applied to a secondary in which the electrode signal is converted by demodulator means into a d-c signal whose magnitude is a function of flow rate and whose polarity depends on the sense of the electrode signal. This d-c signal is converted into variable-frequency pulses which exhibit a duty cycle proportional thereto, the pulses being sampled and fed back through a feedback loop to one input of a summing junction to which the electrode signal is also applied as another input, the ouptut of the junction being fed to the demodulator means.

Abstract: An electronic totalizer interposable in the line of a two-wire transmitter having a transducer which converts a metered variable into a current signal that is conveyed over the line to a receiving station, the same line delivering direct current power from the station to the transducer and to the totalizer. The totalizer input circuit includes a resistor through which the current signal flows to produce a corresponding voltage signal, the voltage signal being applied to a resettable integrator to produce a time-integrated voltage which rises above a base level at a rate depending on the varying magnitude of the voltage. The rising integrated voltage is applied to a comparator having a threshold set by a reference voltage to produce an output signal when the integrated voltage reaches the threshold. The output signal is fed back to the integrator to effect resetting thereof to the base level, the output signal also serving to trigger a one shot generating a pulse which is applied to a digital counter.

Abstract: A continuous analyzer for accurately measuring the free chlorine residual in a chlorinated water supply having an ammonia content which gives rise to a combined chlorine residual whose bactericidal effectiveness is poor as compared to free chlorine. The analyzer includes an amperometric cell through which a sample from the supply is conducted, the cell being provided with a measuring electrode and a counter electrode. Connected in series with the electrodes is an external voltage source whose level is set to impress a potential on the measuring electrode at which the current flow in the cell as a result of the chlorine content of the sample increases progressively in accordance with the concentration of free chlorine residual, the cell being essentially insensitive to combined chlorine residual.

Abstract: A mating device for a cartridge-type fuse to facilitate its insertion in a holder and the removal therefrom. The fuse has a tubular casing whose ends are enclosed by terminal caps which are engageable by the spring clips of the holder. The fuse mate is molded of synthetic plastic material configured to define a block-shaped socket having a longitudinal channel therein adapted to accommodate the tubular casing of the fuse and lateral inlet jaws which are dilatable to admit the casing into the channel, the socket being integral with the underside of a rectangular shield which protectively covers the entire fuse and the "live" holder clips. Formed on the upper side of the shield and integral therewith is a handle having concave sides to define finger depressions and a face which lends itself to marking.

Abstract: A flowmeter of the vortex type in which an obstacle assembly mounted in a flow tube causes vortices to be shed at a frequency that is a function of flow rate. The assembly includes a block having a predetermined geometry fixedly mounted across the flow tube at right angles to the direction of flow. Fitting over the front face of the block is a replaceable adapter cap having a channel therein which conforms to the profile of the block and acts as a socket therefor. The formation of the adapter cap is such as to effectively expand the cross-section of the block without altering the basic geometric configuration thereof whereby the resultant expanded block restricts the effective area in the flow tube of fluid passing by the block, thereby making it possible to measure flow rates below the normal operating range of the meter.