초록 ▼

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 mag

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.

대표청구항 ▼

In a water meter having a path for transmitting water which is to be measured by said meter, with said measurement being taken in terms of a predetermined unit of volume, a rotatable body positioned in said path to turn a number of times proportional to the volume of the water that flows through sai

In a water meter having a path for transmitting water which is to be measured by said meter, with said measurement being taken in terms of a predetermined unit of volume, a rotatable body positioned in said path to turn a number of times proportional to the volume of the water that flows through said path in either a normal or a reverse direction of flow, means for indicating the volume of the water used, and transmitting means responsive to rotation of said body for causing said indicating means to display the volume of the water used in terms of said predetermined unit, the improvement wherein said transmitting means comprises: a. a permanent magnet rotatable with said rotatable body; b. a magnetic field sensor positioned in the field of said permanent magnet, said sensor comprising first and second ferromagnetic magnetoresistive elements responsive to the rotating magnetic field of said magnet for respectively generating first and second output signals, said first and second elements producing a predetermined phase difference between said first and second output signals; c. wave-shaping means for shaping each of said first and second output signals to form first and second sequence of pulses; d. totalizing means comprising: (1) flow sense detecting means responsive to said first and second pulse sequences for producing a normal and an inverse flow pulse signals, the number of pulses of said normal flow of pulse signal and the number of pulses in said inverse flow of pulse signal being equal to twice the number of rotations of said magnet which are actually caused by the water flowing through said path in either said normal or said reverse directions, respectively; and (2) calculating means responsive to the pulses of said flow pulse signals to produce said totalizer output signal in terms of said predetermined units of volume, said calculating means subtracting a number of pulses of said inverse flow pulse signal from a number of pulses of said normal flow pulse signal; and e. means responsive to said totalizer output signal for driving said indicating means to display the amount of water that is used.