JP3251852B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow meter for detecting the rotation of a rotor that rotates in accordance with the flow rate of a liquid flowing into a measuring chamber and measuring the flow rate of the liquid from the number of rotations.

[0002]

2. Description of the Related Art Conventionally, as a flow meter for measuring a flow rate of a liquid, a rotary piston type flow meter (hereinafter, referred to as a flow meter) is often used because of its reliability. This flowmeter has an annular groove-like measuring chamber provided with an inlet and an outlet for liquid, and a predetermined amount while the rotor swings and rotates via an eccentric bearing rotatably arranged at the center position. Each liquid is discharged from the outlet. A magnet is implanted at the center of the rotor, and the magnet rotates around the weighing chamber with the swinging rotation of the rotor, so that a rotating magnetic field of the magnet is generated. Further, a magnetic detection element having directivity of magnetic sensitivity in one direction on the measurement chamber side is disposed at a position separated from the measurement chamber and on the rotating magnetic field of the magnet. By detecting the passage, the rotation of the rotor is detected, and the flow rate of the liquid is measured from the number of rotations.

[0003]

In the flowmeter, in order to improve the measurement accuracy, a plurality of magnetic resistance elements are provided on the rotating magnetic field of the magnet so that a plurality of detection signals can be obtained per one rotation of the rotor. It must be arranged and a plurality of magnets must be implanted in the rotor. Therefore, the smaller the flow meter, the shorter the distance between the magnets,
Even when the magnet approaches or separates from the magnetism detecting element, the change amount of the output voltage becomes small, so that it is impossible to detect the passage of the magnet.

SUMMARY OF THE INVENTION The present invention has been made for the purpose of eliminating the above-mentioned drawbacks.
An object of the present invention is to provide a flow meter capable of obtaining a plurality of rotation detection pulses per rotation of a rotor by using a plurality of magnetic detection elements.

[0005]

A weighing chamber having a liquid inlet and a liquid outlet is provided. The weighing chamber moves along the inner wall of the weighing chamber via an eccentric bearing rotatably arranged on the center line of the weighing chamber. A rotor having a bottomed cylindrical shape that swings and rotates while a magnet is planted at the center of the rotor so that the N-pole and S-pole extend in the same direction as the rotor axis. While a rotating magnetic field is generated, a magnetoresistive element located in a position separated from the measuring chamber and near the center of the rotating magnetic field and having directivity of magnetic sensitivity in four surrounding directions is formed in these four directions. The plane is arranged so as to extend in parallel with the rotation plane of the magnet, the rotation of the rotor is detected from the rotation of the magnet, and the flow rate of the liquid is measured from the number of rotations.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary piston type flow meter according to an embodiment of the present invention will be described below with reference to the drawings. FIG.
In FIG. 2 and FIG. 2, reference numeral 1 denotes a rotary piston type flow meter (hereinafter, referred to as a flow meter), which measures an inlet (not shown) and an outlet (not shown) of a liquid and an annular groove communicating therewith. A flow meter main body 2 having a chamber 2a, a separating plate 3 for closing the measuring chamber 2a, and a measuring chamber lid 4 for pressing the separating plate 3 toward the flow meter main body 2 are provided. The flow meter main body 2 is provided with a cylindrical partition wall 2b projecting toward the measuring chamber side 2a and having an open end, and a bottomed cylindrical member between the wall surface of the measuring chamber 2a and the outer periphery of the partition wall 2b. Of the rotor 5 are accommodated with the bottom upper side. At the center of the rotor 5, a rotor shaft 5a is implanted, and the rotor shaft 5a is mounted on an eccentric bearing 6 rotatably held on the center of the measuring chamber 2a in the partition wall 2b. Is configured to be swingably rotatable while moving along the inner wall in the measuring chamber 2a. The eccentric bearing 6 has a plurality of rotor shaft mounting holes 6a whose distances from the center are slightly different from each other.
The gap between the inner wall of the measuring chamber 2a and the outer periphery of the rotor 5 can be adjusted by changing the position of the measuring chamber 2a from the center.

A magnet 7 is implanted at the center of the bottom of the rotor 5 with the N-pole and S-pole in the same direction as the rotor axis, and a rotating magnetic field of the magnet 7 is generated as the rotor 5 rotates. Is configured. A signal processing unit 1 is provided inside the measuring chamber lid 4 separated from the measuring chamber 2a.
A substrate 11 on which a magnetic resistance element 9 as an example of a magnetic detection element is mounted is mounted on the measurement chamber 2.
It is arranged along the separation plate 3 at a position separated from the position a, and is configured to detect the passage of the magnet 7 at a position separated from the rotation plane of the magnet 7 and near the center of the rotating magnetic field. The magnetic resistance element 9 is shown in FIGS.
As shown in (1), it has directivity of magnetic sensitivity (X range, Y range) in four surrounding directions, and the plane formed in these four directions is configured to extend in parallel with the rotation plane of the magnet 7. Moreover, the magnetic resistance element 9 is configured to output an output voltage in two positive and negative directions with respect to a magnetic field in two orthogonal directions, so that the output voltage in the other direction is not affected when passing through the magnet 7. ing. The output voltage of the magnetic resistance element 9 is controlled by the amplifying unit 1 constituting the signal processing unit 10.
2. The pulse is converted into a rotation detection pulse via the pulse conversion unit 13 and the counting unit 14, the number of rotations of the rotor 5 is measured from the number, and the flow rate of the liquid is measured from the number of rotations, and this is displayed on the display unit 15. It is configured to be.

In the flow meter, when the liquid flows from the inlet, the liquid enters the measuring chamber 2a, moves in the measuring chamber 2a while swinging the rotor 5, and is discharged from the outlet. At this time, as the rotor 5 rotates, the magnet 7 disposed at the center of the rotor 5 rotates to generate a rotating magnetic field around the magnetic resistance element 9. Therefore, the magnetic resistance element 9
When the magnet 7 approaches the magnetic resistance element 9 in one sensitivity direction, the output voltage increases. When the magnet 7 moves away from the magnet 7, the output voltage decreases, and an output voltage having a positive waveform shown in FIG. 4 is obtained. Further, when the rotor 5 rotates beyond 90 degrees, the direction of the magnetic field from the magnet changes by 90 degrees, the polarity of the output voltage becomes negative, and an output voltage having a negative waveform similar to that when the output voltage is positive is generated. can get. The output voltage is converted into a rotation detection pulse, the number of which is counted, the flow rate of the liquid is calculated from the counted value, and displayed.

During this time, when the rotor 5 makes one rotation, the magnetoresistive element 9 alternately outputs two positive and negative output voltages, and outputs four rotation detection pulse signals in one rotation. Four rotation detection pulses can be obtained per rotation. Therefore, when outputting a plurality of rotation detection pulses per rotation of the rotor, only one magnet 7 and one magnetic detection element are required, and there is no need to provide extra magnet 7 and magnetic detection element 9, and the flow meter body becomes small. Also, it is possible to provide a flow meter with high resolution.

[0010]

As described above, according to the present invention, magnets are implanted in the rotor of a rotary piston type flow meter which rotates in accordance with the flow rate of a liquid so that the N and S poles extend in the same direction as the rotor axis. In addition, a rotating magnetic field is generated in accordance with the rotation of the rotor. Since the plane formed in the direction is arranged so as to be parallel to the rotation plane of the magnet, one magnet and one magnetic detection element can be obtained, and a plurality of detection pulses can be obtained per one rotation of the rotor.
There are advantages, such as being able to provide an inexpensive, high-resolution flow meter that can be used with small flow meters.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an outline of the present invention.

FIG. 2 is a sectional view schematically illustrating a rotary piston type flow meter according to the present invention.

FIG. 3 is an explanatory diagram showing the magnetic sensitivity of the magnetoresistive element according to the present invention.

FIG. 4 is an output waveform diagram of the magnetoresistive element according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flowmeter 2 Flowmeter main body 2a Measuring chamber 2b Partition wall 3 Separation plate 4 Metering chamber lid 5 Rotor 5a Rotor shaft 6 Eccentric bearing 6a Rotor shaft mounting hole 7 Magnet 9 Magnetic resistance element 10 Signal processing unit 11 Substrate 12 Amplifying unit 13 Pulse conversion Unit 14 Counting unit 15 Display unit

Claims (1)

(57) [Claims] An annular groove-like measuring chamber having an inlet and an outlet for liquid is provided. The measuring chamber moves along an inner wall of the measuring chamber via an eccentric bearing rotatably arranged on the center line of the measuring chamber. The rotor has a bottomed cylindrical rotor that swings while rotating. A magnet is implanted at the center of the rotor so that the N-pole and S-pole extend in the same direction as the rotor axis. A magnetic resistance element having directivity of magnetic sensitivity in four directions around a position spaced apart from the measuring chamber and near the center of the rotating magnetic field is configured in these four directions. A flowmeter, wherein a flat surface extends parallel to a rotation plane of a magnet, and the rotation of the rotor is detected from the rotation of the magnet, and the flow rate of the liquid is measured from the number of rotations.