Abstract: An electromechanical sensor is provided which comprises: a first silicon wafer which defines a resonant element; wherein the resonant element is doped with approximately the same impurity concentration as a background dopant concentration of the first wafer; and a second single crystal wafer which defines a device for coupling mechanical stress from the second wafer to the resonant element; wherein the first and second wafers are fusion bonded together.

Abstract: Optimum routing for communications between a central control unit (CCU) and remote units (nodes), such as electricity meters, distributed on an electrical power line is established by broadcasting from the CCU an interrogation signal to be received by the remote units. In response to a receipt of the interrogation signal, each remote unit returns an acknowledgement signal, time multiplexed with the acknowledgement signals of the other remote units, to the CCU which determines which units, if any, are "mute", i.e., have not acknowledged. The CCU then selects remote units in proximity to the mute remote units if it has already a good knowledge of the network or at random otherwise, to function as relays and repeats interrogation of the remote units via the relays. This process is repeated, if necessary, until communication paths between the CCU and all remote units are established directly or via delay units, to form maps.

Abstract: A differential electrical current shunt which is particularly adapted for the measurement of large currents with high accuracy and substantially free of errors due to ageing, connection resistance and differentials therein and thermally induced resistance changes. The shunt, according to the invention divides the large current into two substantially equal portions by forming a preferably elongated aperture in a conductor carrying the large current; the two portions of the conductor formed by the aperture having substantially equal but slightly differing resistances. The two conductor portions are formed with respect to a core such that the conductor portions each form a single turn coil on the core with the induced flux from each conductor portion opposing that included in the coil by the other of the two conductor portions.

Abstract: A single optical port in an electric meter is multiplexed between at least two internal systems by using a multiplexer circuit which has a set of data lines which can be connected to the optical port and to one of the internal systems. The multiplexer is controlled by means of a magnetic reed switch which is mounted within the cover of the meter, so no mechanical changes to the meter cover are required.

Abstract: The transmitter in a power line communications system applies to the power line encoded logical-one and logical-zero bit signals consisting of signals formed respectively of predetermined different sequences of frequencies. The receiver, coupled to the power line, includes a first homodyne, non-coherent, quadratic demodulator for demodulating the logical-one bits and a second for demodulating the logical-zero bits. The first demodulator produces, locally, and in first and second channels, respectively, a first reference signal that is a replica of the logical-one bit sequence of frequencies and a second reference signal that is the replica in quadrature. The second demodulator produces, locally, and in third and fourth channels, respectively, cooresponding third and fourth reference signals for the logical-zero bit sequence. Each of the four reference signals is applied to a corresponding analog multiplier for multiplication by the input signal in each channel.

Abstract: A triangle waveform generator for a pulse-width amplitude multiplier includes a digital-to-analog converter and a charge transfer network. Clocked signals applied to the converter, which includes a resistor chain for providing a set of different potentials, sequentially select ones of the potentials and supply two of them to the charge transfer network. The network weights each of the potentials received, then combines them at an output node. By employing appropriate clocking of the converter, a triangular waveform having a plurality of discrete steps results.

Abstract: A high accuracy power meter capable of measuring power supplied or consumed in multiple phases of a distribution system is fabricated as an integrated circuit. Voltage and current sensing transducers coupled to the power meter provide input signals having a potential proportional to the voltage and current in the distribution system. A low charge injection pulse width amplitude multiplier using a digitally-synthesized triangular wave is provided for each phase. Each multiplier receives the input signals and provides an output signal having a current proportional to the product of voltage and current in that phase of the distribution system.Charge from the multiplier output currents for all phases is accumulated in a capacitor connected across an autozeroing amplifier, which corrects for its own offset voltage. The amplifier output controls a switch connected between a reference potential and the capacitor.

Abstract: A vortex flowmeter including a differential pressure transducer with high common mode rejection. No diaphragms are required. A relatively thick machined recess at one end of the vortex shedding body concentrates and transmits the vortex shedding differential pressure to strain transducers located outside the fluid flow conduit. Embodiments are disclosed in which piezoelectric elements and reflective optical fibers are used as strain transducers. The described arrangements allow the mechanical clamping of the transducers and their easy removal without a flow shut down. The shedder shape is optimized in relation to the differential transducer to strengthen the shed vortices and improve the linearity and repeatability of the meter.

Abstract: A domestic reverse osmosis water purification system utilizing few parts in the controller valve mechanism enhances reliability and economic feasibility. All surfaces of the controller valve mechanism in contact with water are non-metallic and are constructed of FDA approved materials. In addition to its normal function of metering the reject water flow, the controller valve mechanism allows the homeowner to easily rinse the reverse osmosis membrane and conserves water by automatically stopping influent water flow when the product storage tank is full.

Abstract: A vortex flowmeter including a differential pressure transducer with high common mode rejection. No diaphragms are required. A relatively thick machined recess at one end of the vortex shedding body concentrates and transmits the vortex shedding differential pressure to strain transducers located outside the fluid flow conduit. Embodiments are disclosed in which piezoelectric elements and reflective optical fibers are used as strain transducers. The described arrangements allow the mechanical clamping of the transducers and their removal without a flow shut down. The shedder shape is optimized in relation to the differential transducer to strengthen the shed vortices and improve the linearity and repeatability of the meter.

Abstract: A Coriolis-type mass flow meter which uses two parallel, omega-shaped conduits and deduces mass flow rate from changes in the phase difference of signals from sensors at the outboard curved portions of the conduits which measure the relative positions of the conduits' sizes.

Abstract: An upstream flow conditioner (rectifier) for a vortex flowmeter. The flow conditioner is constructed with flow rectification vanes placed parallel to the axis of the vortex shedding body at the inlet section of the meter body or between flanges for short meter bodies and insertion meters. The vanes comprise three equally spaced apart flat strips which are inserted in slotted grooves on the inlet side of the meter body or on a plate that can be inserted between flanges. The thickness and the depth of the strips and their distance from the shedding body are optimized to ensure the reproduction of a desired turbulence level and mean fluid velocity profile in the plane perpendicular to the shedding body.

Abstract: A fluid strainer and flow corrector for use with a fluid flow measurement device, such as a turbine-type flow meter, consists of a generally conical grid of ribs attached to an annular base flange. The base flange of the strainer/flow corrector fits into a groove formed on the inlet side of the housing of the flow meter and is held in place by means of a flexible snap-ring. The strainer/flow corrector is arranged with its apex upstream of the flange portion with respect to the direction of fluid flow through the inlet of the flow meter. The spacing between the ribs is chosen as to block the flow of debris which might be present in the fluid flowing through the flow meter. The spacing between the ribs is also chosen to provide a desired velocity profile to the fluid. The strainer/flow corrector may be easily removed or replaced without disconnecting the flow meter from its associated pipework.