Other

Carnegie Mellon University

Energy Controls, Inc.

Richard L Longini

Ronald J Zdrojkowski

A method and apparatus for digitally measuring electrical energy consumption from a transmission line carrying alternating current. Instead of actually measuring current from a transmission line conductor, the time derivative of the magnetic field induced by current flowing in the conductor is measured thereby obtaining a reading which is proportional to the time derivative of the current flow. Using an appropriate microcomputer, the time derivative of the magnetic field (the magnetic field rate of change) is represented with an algorithmic series for expressing cyclic phenomena, such as the Fourier series of low order. An approximation of the power consumption is then computed by converting the time derivative of the current as expressed in the algorithmic series and a voltage measurement from the conductor mathematically to a power reading, and the power reading is summed to obtain a number value proportional to the energy consumption. Even harmonics and high frequency harmonics may be eliminated in the algorithmic expression of the current derivative to further simplify computer computations and required hardware, and the magnetic rate of change pickup and the voltage pickup are preferably filtered to remove unwanted noise.

Method and apparatus for digitally measuring electrical energy

The system includes a central fluid heater or cooler and an electrically driven centrifugal pump which pumps fluid therefrom to a supply main from which individual lines lead to each unit supplied. Return lines from each unit bring the used fluid back to the heater or cooler. The supply main is provided with a single digital flow meter or equivalent measuring device and digital thermometer. Each supply line has a control valve and means to signal the opening and closing of that valve. Each return line includes a digital thermometer. The signals from the above-mentioned apparatus are supplied to a microprocessor. The quantity of energy used by each unit is proportional to the volume of fluid received, which is metered by the change in flow when the unit valve is opened and the change in the opposite direction when the valve is closed, multiplied by the temperature difference between the received and the returned water. The microprocessor is multiplexed to monitor each unit in succession at short time intervals and make necessary calculations.

Energy use monitoring system

An apparatus is provided for detecting the quantity of a specific gas hereinafter simply called 'gas' in a carrier gas when water vapor is present. The gas and the carrier gas are passed through a whistle chamber which produces a resonating frequency. The resonant frequency changes as a function of the fraction of the gas, temperature and water vapor. An output signal is produced which is a function of the resonant frequency. A correction device senses water vapor and temperature and produces an output signal which is a function of the water vapor and the temperature. A receiving means receives the output signals and produces a resultant signal which is a function of only the fraction of the gas.

Apparatus and method for detecting a fraction of a gas

Disclosed are a method and an apparatus for magnetically recording and reproducing physiological information such as in an electrocardiogram. The ECG signal is pulse width modulated (PWM), and the transition points, or zero crossings are stored on magnetic tape. The original PWM signal is then reproduced from the output of the playback head by reacting to the simultaneous occurrence of zero crossings and large magnitude derivative signals. Also disclosed is the concept of automatically reacting to recorded audible information during the reconstruction of the original PWM signal.

Growing community of inventors

Pittsburgh, PA, United States of America

Richard L Longini