Water meter comprising a ferromagnetic magnetoresistor coupled to a rotatable permanent magnet
US4253341A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1979 |
| Grant date | Mar 3, 1981 |
| Priority date | — |
| Expiry date | Apr 24, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/075
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A water meter eliminates the usual conversion gear trains by using a permanent magnet which rotates in proportion to the volume of water to be measured. A magnetic field sensor, comprising a ferromagnetic magnetoresistor, produces a sensor signal which varies as a function of the rotation of the magnet. A wave shaper forms the sensor signal into a sequence of pulses which drive a totalizer for producing a signal indicative of the volume of the water used. The output of the totalizer is supplied to an indicator device which displays the total amount of water passing through the meter, in terms of a predetermined unit of measure. Preferably, the sensor comprises at least two magnetoresistors for producing two sensor signals with a phase difference therebetween. The wave shaper then produces two pulse sequences for identifying a normal and an inverse flow of water, respectively. These two sequences cause the totalizer to count up or down, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.