Abstract: An electromagnetic speedometer for a boat having hull containing an opening includes an electromagnetic coil supported by the hull for establishing an electromagnetic field in the water adjacent the hull opening. A plurality of electrodes are supported by an arrangement that both closes the hull opening and supports the electrodes in engagement with the water adjacent the hull opening. The electrodes are connected by conductors with a velocity measuring circuit arranged above the hull interior surface. Preferably, the electrode support arrangement includes guide tubes supporting the electrodes for removal relative to the boat hull, thereby to permit cleaning of the electrodes. The guide tubes are closed by valves when the electrodes are removed from the assembly. In one embodiment, the electromagnetic coil is of the end-fired type, and in another embodiment, the electromagnetic coil is annular and is arranged above and below the hull.

Abstract: An electromagnetic boat speedometer includes a boundary layer velocity compensating arrangement comprising a primary coil for producing a primary electromagnetic field within a relatively large first volume of water, a secondary coil for producing a secondary electromagnetic field within a relatively small portion of the first volume of water immediately adjacent the hull of the boat, and a set of first electrodes removably mounted in one or more openings in the hull of the boat, such that the tips of the first electrodes extending into the relatively small water portion. In one embodiment, the coils are simultaneously energized in opposition, so that the primary and secondary electromagnetic fields are in opposition. In a second embodiment, the coils are energized alternately, and the signals produced by the electrodes are modified to achieve the desired boundary layer compensation. A second set of second electrodes may be included in the second embodiment.

Abstract: An electromagnetic speedometer for a boat having hull containing an opening includes an electromagnetic coil supported by the hull for establishing an electromagnetic field in the water adjacent the hull opening. A plurality of electrodes are supported by an arrangement that both closes the hull opening and supports the electrodes in engagement with the water adjacent the hull opening. The electrodes are connected by conductors with a velocity measuring circuit arranged above the hull interior surface. Preferably, the electrode support arrangement includes guide tubes supporting the electrodes for removal relative to the boat hull, thereby to permit cleaning of the electrodes. The guide tubes are closed by valves when the electrodes are removed from the assembly. In one embodiment, the electromagnetic coil is of the end-fired type, and in another embodiment, the electromagnetic coil is annular and is arranged above and below the hull.

Abstract: An electromagnetic speedometer for a boat having hull containing an opening includes an electromagnetic coil supported by the hull for establishing an electromagnetic field in the water adjacent the hull opening. A plurality of electrodes are supported by an arrangement that both closes the hull opening and supports the electrodes in engagement with the water adjacent the hull opening. The electrodes are connected by conductors with a velocity measuring circuit arranged above the hull interior surface. Preferably, the electrode support arrangement includes guide tubes supporting the electrodes for removal relative to the boat hull, thereby to permit cleaning of the electrodes. The guide tubes are closed by valves when the electrodes are removed from the assembly. In one embodiment, the electromagnetic coil is of the end-fired type, and in another embodiment, the electromagnetic coil is annular and is arranged above and below the hull.

Abstract: An electromagnetic boat speedometer includes a boundary layer velocity compensating arrangement comprising a primary coil for producing a primary electromagnetic field within a relatively large first volume of water, a secondary coil for producing a secondary electromagnetic field within a relatively small portion of the first volume of water immediately adjacent the hull of the boat, and a set of first electrodes removably mounted in one or more openings in the hull of the boat, such that the tips of the first electrodes extending into the relatively small water portion. In one embodiment, the coils are simultaneously energized in opposition, so that the primary and secondary electromagnetic fields are in opposition. In a second embodiment, the coils are energized alternately, and the signals produced by the electrodes are modified to achieve the desired boundary layer compensation. A second set of second electrodes may be included in the second embodiment.

Abstract: One aspect provides a method including determining that an absolute pressure sensor is not submersed in a fluid; measuring an atmospheric pressure with the absolute pressure sensor to determine an offset pressure measurement; submersing the absolute pressure sensor in a fluid; and measuring pressure with the absolute pressure sensor; wherein a compensated pressure measurement of the fluid is determined. Other embodiments are disclosed.

Abstract: An electromagnetic speedometer for a boat having hull containing an opening includes an electromagnetic coil supported by the hull for establishing an electromagnetic field in the water adjacent the hull opening. A plurality of electrodes are supported by an arrangement that both closes the hull opening and supports the electrodes in engagement with the water adjacent the hull opening. The electrodes are connected by conductors with a velocity measuring circuit arranged above the hull interior surface. Preferably, the electrode support arrangement includes guide tubes supporting the electrodes for removal relative to the boat hull, thereby to permit cleaning of the electrodes. The guide tubes are closed by valves when the electrodes are removed from the assembly. In one embodiment, the electromagnetic coil is of the end-fired type, and in another embodiment, the electromagnetic coil is annular and is arranged above and below the hull.

Abstract: One aspect provides a method including determining that an absolute pressure sensor is not submersed in a fluid; measuring an atmospheric pressure with the absolute pressure sensor to determine an offset pressure measurement; submersing the absolute pressure sensor in a fluid; and measuring pressure with the absolute pressure sensor; wherein a compensated pressure measurement of the fluid is determined. Other embodiments are disclosed.

Abstract: An electromagnetic flowmeter includes at least one electromagnet coil arranged outside a liquid flow passage for generating an electromotive force in the liquid flow, and at least one pair of electrodes adjustably extending within the liquid flow for generating a velocity component signal. Preferably, two collinearly arranged coils are provided externally on opposite sides of the liquid flow passage, and a first set of two orthogonally-arranged pairs of coplanar electrodes are mounted on an adjustable probe strut that extends into the liquid flow. For greater accuracy, a Hall-effect device is provided on the probe. Additional sets of electrode pairs may be secured to the strut in planes parallel to the first electrode set. A second pair of collinear coils may be mounted externally of the liquid passage and orthogonally relative to the first coil pair, the two pairs of coils being alternately energized to produce three orthogonally arranged velocity components.

Abstract: An electromagnetic flowmeter includes at least one electromagnet coil arranged outside a liquid flow passage for generating an electromotive force in the liquid flow, and at least one pair of electrodes adjustably extending within the liquid flow for generating a velocity component signal. Preferably, two collinearly arranged coils are provided externally on opposite sides of the liquid flow passage, and a first set of two orthogonally-arranged pairs of coplanar electrodes are mounted on an adjustable probe strut that extends into the liquid flow. For greater accuracy, a Hall-effect device is provided on the probe. Additional sets of electrode pairs may be secured to the strut in planes parallel to the first electrode set. A second pair of collinear coils may be mounted externally of the liquid passage and orthogonally relative to the first coil pair, the two pairs of coils being alternately energized to produce three orthogonally arranged velocity components.

Abstract: Apparatus for measuring the rate of flow of a fluid in a conduit includes a receptor assembly arranged on the external surface of the conduit, and a removable external connector assembly including an electromagnet for establishing a magnetic field that extends transversely across the conduit, and a plurality of circumferentially arranged electrodes that are insertable into direct contact at their tips with the fluid in the conduit via sealable gland passages contained in the receptor assembly. A calibration adjustment arrangement is provided for adjusting the calibration factor of the flow signal processing system as a function of the conduit cross-sectional area. In a first embodiment, the glands are self sealable, whereupon the gland passages are automatically closed when the electrodes are removed therefrom.

Abstract: A flowmeter utilizing velocity at the surface of a fluid and lookdown level sensors is mounted within a manhole without requiring entry into the manhole by the installer. The velocity and level sensors generate first and second energy signal beams which are directed toward the same vicinity of the fluid surface which reflects the beams back to the sensors surface velocity signal representative of the velocity of scatters on the fluid surface is produced from the Doppler frequency shift between the directed and reflected first beam. This signal is modified to produce a mean velocity signal. A level signal is produced by determining the air space between the sensor and the fluid surface from the directed and reflected second beam and relating changes in the air space to changes in fluid level in accordance with the configuration of the pipe. Fluid flow can be calculated from the mean velocity and fluid level signals.

Abstract: An open-channel flowmeter is calibrated by the use of local velocity and level characteristics existing at a given site, as measured by the flowmeter itself. Stored reference relationships that have been either theoretically or experimentally derived are compared to the velocity level relationships at any particular site so as to determine a correction factor which is valid at that site so as to modify the sensed velocity to be an accurate approximation of the average velocity under those site conditions. A local velocity signal is modified so as to make it an accurate approximation of the mean velocity for open-channel flowmeters of the level/velocity type.

Abstract: An improved flowmeter apparatus and method for accurately determining the liquid flow rate in a conduit and the mass flow rate of selected pollutant components entrained in the flow stream characterized by injecting at least two trace materials into the flow stream at a plurality of locations and, after allowing adequate time for the trace materials to reach a downstream sampling location, collecting a plurality of samples of liquid from the flow stream containing the trace materials. By comparing the concentrations of the trace materials found in the sample, the degree of mixing of the trace materials in the flow stream, and hence the accuracy of the flow stream flow rate and pollutant component mass flow rate measurements, can be evaluated. Other injecting methods for more thoroughly mixing the trace materials with the flow stream are also disclosed.

Abstract: A magnetic flowmeter includes a flow tube that is connected in fluid-conducting relation between a pair of axially spaced sections of a conduit, a first electrical connector being fixed to the outer surface of the flow tube and including first terminals electrically connected with spaced internal electrodes, respectively, that contact the fluid flowing through the tube. A second electrical connector is provided for separable connection with the first connector, which second connector includes an end-fire electromagnet for establishing a transverse magnetic field in the flow tube via the first connector, and second terminals for connecting the electrodes with a flow-indicating meter via the first terminals, respectively, and a cable. In order to calibrate the meter for use with a plurality of flow tubes having different internal cross-sectional dimensions, respectively, the first and second connectors are provided with cooperating size coding and decoding devices, respectively.

Abstract: A pump station flowmeter is disclosed including a sudden high inflow change detection circuit for eliminating from a series of emptying characteristic calculations taken over a period of time those measurements which are outside of a predetermined acceptance range. The wet well dimensions, level detector signals, clock signals and pump status signals are supplied as inputs to both a volume rate of change calculator and to the sudden high inflow change detector. In the event of an undesirable measurement, the sudden high inflow changes detection circuit operates a gate to isolate the volume rate of change calculator from the emptying characteristic calculator that calculates outflow. A flow integrator is provided for calculating volume per cycle from the volume rate of change signal, and an inflow calculator serves to produce inflow from the volume per cycle signal.

Abstract: A pump station flowmeter is disclosed including a sudden high inflow change detection circuit for eliminating from a series of emptying characteristic calculations taken over a period of time those measurements which are outside of a predetermined acceptance range. The wet well dimensions, level detector signals, clock signals and pump status signals are supplied as inputs to both a volume rate of change calculator and to the sudden high inflow change detector. In the event of an undesirable measurement, the sudden high inflow change detection circuit operates a gate to isolate the volume rate of change calculator from the emptying characteristic calculator that calculates outflow. A flow integrator is provided for calculating volume per cycle from the volume rate of change signal, and an inflow calculator serves to produce inflow from the volume per cycle signal.

Abstract: An electromechanical flowmeter includes a coil arrangement located completely outside the fluid conduit for producing a magnetic field that extends concentrically about the longitudinal axis of the conduit, the portion of the field adjacent the inner periphery of the conduit being stronger than that adjacent the center of the conduit. First electrodes are mounted on the interior wall surface of the conduit within the magnetic field, and second electrodes are arranged at a location generally unaffected by the field. In the preferred embodiment, the second electrode is mounted on the interior wall surface outside the magnetic field in longitudinally-spaced relation relative to the first electrodes, whereby the provision of any flow-obstructing electrode within the conduit is completely avoided. In a non-preferred embodiment, the second electrode is mounted centrally with the conduit relative to the longitudinal axis thereof.

Abstract: A sensor for measuring the mean velocity of fluid flow in a conduit senses flow velocities at a number of locations across the interior of the conduit to yield an accurate mean flow signal. The sensor includes a tubular housing which extends across the interior of the conduit. An electromagnet is arranged in the housing and produces an electromagnetic field in the fluid, the axis of the field extending normal to the direction of fluid flow. A plurality of electrodes are arranged in spaced relation along the length of the housing and in diametrically opposed pairs on opposite sides of the housing. The lines which pass through each electrode pair are arranged perpendicular to the direction of fluid flow. The electrodes produce electrical signals in response to the flow of fluid through the field, with each signal being a function of the velocity of fluid flow adjacent each electrode. The signals are combined to produce the mean flow velocity output signal.

Abstract: A pressure level sensor for mounting a pressure transducer in a fluid flow channel. The sensor is characterized by an elongated wedge-shaped configuration wherein the width of the convex front wall portion is less than that of the rear wall portion which in turn is less than the length of the sensor. The side wall portions of the sensor each have concave surfaces, the radius of curvature of which is a function of the length of the sensor. At least one side wall portion contains a horizontal pressure port for communication with the pressure transducer. The front, rear, and side wall portions are tapered and curved vertically inwardly and terminate at a top wall portion. When the sensor is arranged on the bottom of the channel with the front wall portion facing upstream relative to the fluid flow, the velocity vector of the fluid flow is perpendicular to the direction of extension of the opening, thereby to minimize flow velocity effects on the pressure transducer.