Abstract: An apparatus includes a conduit having a generally circular cross-section, and a liquid flow sensor extending into the conduit so that a liquid contacting portion extends generally parallel to an axis of the conduit and is positioned to extend into an interior of the conduit a first distance. An electromagnetic coil is positioned in the housing for generating a magnetic field within the liquid flow. In addition, the sensor includes a pair of spaced apart electrodes defining a second distance therebetween and being exposed on the liquid contacting portion for generating a signal related to the liquid flow rate. Moreover, the second distance is preferably greater than or equal to about two times the first distance and is greater than or equal to about one-tenth a diameter of the conduit. An open channel embodiment of the invention has a cross-section of a predetermined width and an opening in a bottom wall thereof. A liquid flow sensor is positioned in the opening in the open channel.

Abstract: The inductive flow meter and method of exciting a coil includes a coil with unipolar excitation, which generates exciting pulses having a pulse interval therebetween. The length of the pulse interval is shorter than that of an exciting pulse. The associated evaluation circuit includes two alternately clocked channels whose evaluation phases overlap each other in time, the measuring voltage being obtained at the ends of the signal paths by alternately sampling the channels.

Abstract: A sensing apparatus includes a conduit and a liquid flow sensor positioned in a first opening in a conduit. The liquid flow sensor includes an electromagnetic coil positioned in a housing for generating a magnetic field having a predetermined pattern within the conduit so that a relatively strong magnetic field is adjacent the liquid contacting portion and so that a relatively weak magnetic field is adjacent a second opening through which a liquid characteristic sensor is positioned. The liquid characteristic sensor preferably comprises a sensor susceptible to magnetic fields. Accordingly, the liquid characteristic sensor is subject to only a relatively weak magnetic field. For example, the liquid characteristic sensor may be a turbidity sensor or a dissolved oxygen sensor. The second opening is preferably positioned in an arcuate portion of the conduit in a range of about 70 to 110 degrees of rotation from an imaginary line extending longitudinally through a center of the first opening.

Abstract: A liquid flow sensor includes a housing positioned in a conduit and comprises a liquid contacting portion extending generally parallel to an axis of the conduit. An electromagnetic coil is positioned within the housing and cooperates with a pair of electrodes exposed on the liquid contacting portion to generate a signal relating to the liquid flow rate. Liquid velocity profile enhancement is provided to increase the accuracy of the liquid flow rate sensing. In particular, a plurality of projections or transverse ridges may be defined in the liquid contacting portion for causing turbulence in liquid flow adjacent the liquid contacting portion. The conduit may have a cylindrical shape with a circular transverse cross-section. Alternately, the conduit may have an open upper portion defining an open channel. The ridges may preferably be arranged in two bands extending adjacent opposite side edges of the liquid contacting portion. Each band may also include a gap in the ridges adjacent a respective electrode.

Abstract: An apparatus includes a conduit having a generally circular cross-section, and a liquid flow sensor extending into the conduit so that a liquid contacting portion extends generally parallel to an axis of the conduit and is positioned to extend into an interior of the conduit a first distance. An electromagnetic coil is positioned in the housing for generating a magnetic field within the liquid flow. In addition, the sensor includes a pair of spaced apart electrodes defining a second distance therebetween and being exposed on the liquid contacting portion for generating a signal related to the liquid flow rate. Moreover, the second distance is preferably greater than or equal to about two times the first distance and is greater than or equal to about one-tenth a diameter of the conduit. An open channel embodiment of the invention has a cross-section of a predetermined width and an opening in a bottom wall thereof. A liquid flow sensor is positioned in the opening in the open channel.

Abstract: A sensor for liquid flow rate and liquid pressure includes a housing, in turn, including a liquid contacting portion positioned within a liquid carrying conduit. The liquid contacting portion includes a pressure responsive diaphragm. An electromagnetic coil is positioned in the housing for generating a magnetic field within the flow of liquid, and a pair of spaced apart electrodes are exposed on the liquid contacting portion for generating a signal related to the liquid flow rate. A pressure sensing device or mechanism, such as a gauge or transducer, may be operatively coupled to the diaphragm. Accordingly, a compact and reliable sensor for both liquid flow rate and liquid pressure is provided by the present invention. In one embodiment the conduit may have a cylindrical shape with a circular cross-section and in another embodiment, the conduit may be an open channel conduit. Method aspects of the invention are also disclosed.