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: 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 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.