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AN INTELLIGENT INDUCTIVE ENCODER FOR GAS METERING APPLICATION

IP.com Disclosure Number: IPCOM000246134D
Publication Date: 2016-May-11
Document File: 3 page(s) / 112K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention proposes an inductive encoder device for gas metering application. A resonant electronic circuit is supplied with impulsive current that generates a sinusoidal wave that energizes some soft magnetic inductors placed near a rotating composite disc with some sectors of conductive and some sectors of non-conductive material. Gas within a pressure conduit is configured to drive a spindle attached to the rotating disc such that the rotation is proportional to the volume flow of gas. The circuit is configured to detect passage of the conductive sectors of the rotating disc by detecting attenuation of eddy currents. Using a logic circuit to monitor the attenuation of the inductors the number of rotations is counted, and thus the volume of gas passing through in unit time is measured. The number of sectors on the disc and inductors is in function of resolution needs. More sectors and inductors increase the volume calculation resolution. The inductive encoder device provides correct measurement with dirty gas and is less affected by stray magnetic fields.

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AN INTELLIGENT INDUCTIVE ENCODER FOR GAS METERING APPLICATION

BACKGROUND

The invention is related to an encoder for gas metering application. Inductive technology is found in water meters and production line application, but the use of an intelligent inductive encoder in gas metering application is novel. There are various meters like optical and magnetic encoders available for gas metering. Dirty gas with dust or other constituents could cause errors in readings using an optical encoder. A magnetic encoder using Hall Effect sensors or Reed sensors is affected by stray magnetic fields. Moreover, manufacturing optical and magnetic encoders requires expensive components, eventually making these encoders costly. Power consumption of optical and magnetic encoders is relatively high. The measurement of loss of pressure of gas due to minor friction is not credible with the available encoders for gas metering application.

BRIEF DESCRIPTION OF DRAWINGS

The invention discloses an intelligent inductive encoder for gas metering application, wherein:

FIG. 1 illustrates intelligent inductive encoder for gas metering.

DETAILED DESCRIPTION

The invention proposes an inductive encoder device for gas metering application as schematically illustrated in FIG. 1. The intelligent inductive encoder works on the principle of detecting eddy currents. As shown in Fig. 1, a resonant electronic circuit is supplied with impulsive current that generates a sinusoidal wave that energizes some soft magnetic inductors placed near a rotating composite disc. The composite disc is provided with sectors of conductive and non-conductive material. This sinusoidal wave decreases in amplitude as function of time. Due to the eddy currents, this amplitude decreases faster if the conductive sector of the rotating disc is near the inductor. As illustrated in FIG. 1, gas within a pressure conduit is configured to drive a spindle such that the rotation is proportional to the volume flow of gas. The spindle is connected via a pressure seal to the composite disc to drive it. The circuit is thus configured to detect the passage of the conductive sector of the rotating disc every time it passes by an inductor by detecting attenuation of eddy currents. Using a logic circuit to monitor the attenuation of the inductors the number of rotations is counted, and thus the volume of gas passing through the pressure conduit in unit time is measured and recorded. For simplicity the inductive encoder illustrated in FIG. 1 is with a conductive and a non-conductive sector and 2 soft magnetic inductors but, in function of counting resolution requested, it can be with many sectors and many soft magnetic inductors.

FIG. 1: Schematic of an intelligent inductive encoder for gas metering

The detection circuitry is further described....