Metal tube float flowmeter applying magnetic bias technology

Abstract

The utility model discloses a metal tube float flowmeter applying a magnetic bias technology, which comprises a metal tube float flowmeter body, the metal tube float flowmeter body comprises a measuring tube and an indicator, and the measuring tube and the indicator are connected and fixed by screws; the measuring tube comprises a floater and a taper tube, and a bullet metal structure of rod-shaped magnetic steel is arranged in the floater; the indicator comprises a metal shell, window glass is fixedly embedded in the front side of the metal shell, a PCB is installed in the metal shell, and the PCB and the measuring tube are vertically arranged in parallel. By adding the bias magnetic steel, the linear interval of the magnetoresistive sensor can be improved by adopting a magnetic bias technology, measurement errors caused by geomagnetic influence can be reduced, temperature excursion can be reduced or inhibited, the signal-to-noise ratio of the magnetoresistive sensor can be improved, and the magnetoresistive sensor can be applied to weak magnetic coupling micro-flow metal tube float flowmeters to meet use requirements.

Description

Technical Field

[0001] The utility model relates to the technical field of metal tube float flowmeters, in particular to a metal tube float flowmeter using a magnetic bias technology. Background Art

[0002] At present, local indicating type metal tube float flowmeters with small flow rates are widely used. The application of electric remote transmission system can not only realize long-distance signal transmission, but also realize on-site digital display, which greatly improves the measurement accuracy. However, the metal tube float flowmeter with small flow rate adopts the principle of weak magnetic coupling, and has high requirements on the measurement linear interval and measurement range of magnetoresistive sensor. Due to the weak magnetic coupling magnetic field, it is easily affected by the earth's magnetic field and causes measurement errors. For this reason, we propose a metal tube float flowmeter with magnetic bias technology. Utility Model Content

[0003] The utility model aims to solve the shortcomings in the prior art and proposes a metal tube float flowmeter using magnetic bias technology.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A metal tube float flowmeter using magnetic bias technology comprises a metal tube float flowmeter body, wherein the metal tube float flowmeter body comprises a measuring tube and an indicator, wherein the measuring tube and the indicator are connected and fixed by screws;

[0006] The measuring tube comprises a float and a cone tube, wherein a bullet-shaped metal structure of a rod-shaped magnetic steel is built in the float;

[0007] The indicator comprises a metal shell, a window glass is embedded and fixed on the front side of the metal shell, a PCB board is installed in the metal shell, the PCB board is arranged vertically and parallel to the measuring tube, two magnetoresistive sensors are electrically connected to the front side of the PCB board, the magnetoresistive sensors are mounted on the front side of the PCB board, the two magnetoresistive sensors are both located on the left side of the measuring tube, the two magnetoresistive sensors are installed in opposite directions, a bias magnet is mounted on the front side of the magnetoresistive sensor, a plurality of pins are arranged on the magnetoresistive sensor, the bias magnet is attached to the position between the gap between pins 3 and 4 and between pins 5 and 6 of the corresponding magnetoresistive sensor, and the magnetic pole direction of the bias magnet has an N pole corresponding to the gap between pins 3 and 4, and an S pole corresponding to the gap between pins 5 and 6.

[0008] Preferably, a plastic shell is sealed on the outer side of the PCB board, and the rear side of the plastic shell is fixedly connected to the rear inner wall of the metal shell.

[0009] Preferably, the bias magnet is made of iron-chromium-cobalt, the magnetic field strength of the bias magnet is between 45Gs-55Gs, and the fixed size of the bias magnet is 2x1x0.5mm.

[0010] Preferably, the magnetoresistive sensor has four identical sensing units built therein, the four sensing units form a Wheatstone bridge, the differential output of the bridge is proportional to sin2θ, and its output curve is approximately a sine curve.

[0011] Preferably, the measuring tube is used to measure a pipeline through which a medium flows.

[0012] Preferably, the magnetoresistive sensor is a Honeywell HMC1501 magnetoresistive sensor.

[0013] Compared with the existing technology, the beneficial effects of the utility model are:

[0014] The utility model can improve the linear range of the magnetoresistive sensor by adding bias magnet steel, and can reduce the measurement error caused by the influence of geomagnetism, while reducing or suppressing temperature drift, and improving the signal-to-noise ratio of the magnetoresistive sensor. It can be applied to weak magnetic coupling small flow metal tube float flowmeter to meet the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of a metal tube float flowmeter using magnetic bias technology proposed by the utility model;

[0016] Figure 2 This is a structural schematic diagram of a PCB board, a magnetic resistance sensor and a bias magnetic steel connector of a metal tube float flowmeter using magnetic bias technology proposed by the utility model;

[0017] Figure 3 The utility model discloses a curve diagram showing the influence of the bias magnet steel of a metal tube float flowmeter using magnetic bias technology on the sampling of a magnetoresistive sensor.

[0018] In the figure: 1, measuring tube; 101, float; 102, bullet head metal structure; 2, indicator; 201, metal shell; 202, PCB board; 203, magnetoresistive sensor; 2031, bias magnet. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0020] Reference Figure 1-3 A metal tube float flowmeter with magnetic bias technology, comprising a metal tube float flowmeter body, the metal tube float flowmeter body comprising a measuring tube 1 and an indicator 2, the measuring tube 1 and the indicator 2 are connected and fixed by screws, wherein the measuring tube 1 is used to measure a pipeline through which a medium flows;

[0021] The measuring tube 1 comprises a float 101 and a cone tube, wherein a bullet-shaped metal structure 102 of a rod-shaped magnetic steel is built in the float 101, wherein the float 101 is located inside the measuring tube 1 and changes position with the flow rate of the measuring medium;

[0022] The indicator 2 comprises a metal shell 201, a window glass is embedded and fixed on the front side of the metal shell 201, a PCB board 202 is installed in the metal shell 201, wherein the outer side of the PCB board 202 is sealed with a plastic shell, the rear side of the plastic shell is fixedly connected to the rear inner wall of the metal shell 201, the PCB board 202 is vertically parallel to the measuring tube 1, and the front side of the PCB board 202 is electrically connected to two magnetoresistive sensors 203, the magnetoresistive sensor 203 is a Honeywell HMC1501 magnetoresistive sensor, and the magnetoresistive sensor 203 has four identical sensing units built therein, and the four sensing units form a Wheatstone bridge, the bridge differential output is proportional to sin2θ, and its output curve is approximately a sine curve, so the transfer characteristic of the anisotropic magnetoresistive sensor 203 is nonlinear, and when the magnetic field to be measured is very small, the slope of the transfer characteristic is close to zero, and at this time the sensitivity of the magnetoresistive sensor 203 is extremely low;

[0023] The magnetoresistive sensor 203 is mounted on the front side of the PCB board 202. Both magnetoresistive sensors 203 are located on the left side of the measuring tube 1. The installation directions of the two magnetoresistive sensors 203 are opposite. A bias magnet 2031 is mounted on the front side of the magnetoresistive sensor 203. The magnetoresistive sensor 203 is provided with a plurality of pins. The bias magnet 2031 is attached to the position between the gap between pins 3 and 4 and between pins 5 and 6 of the corresponding magnetoresistive sensor 203. The magnetic pole direction of the bias magnet 2031 has the N pole corresponding to the gap between pins 3 and 4, and the S pole corresponding to the gap between pins 5 and 6.

[0024] The bias magnet 2031 is made of iron-chromium-cobalt, the magnetic field strength of the bias magnet 2031 is between 45Gs-55Gs, and the fixed size of the bias magnet 2031 is 2x1x0.5mm; by adding the bias magnet 2031, the utility model can use magnetic bias technology to improve the linear range of the magnetoresistive sensor 203, and can reduce the error caused by the influence of the geomagnetic field on the measurement, while reducing or suppressing the temperature drift, and improving the signal-to-noise ratio of the magnetoresistive sensor 203. It can be applied to weak magnetic coupling small flow metal tube float flowmeters to meet the use requirements.

[0025] Working principle: When in use, since the four sensing units built into the magnetoresistive sensor 203 form a Wheatstone bridge, the differential output of the bridge is proportional to sin2θ, and its output curve is approximately a sine curve, the transfer characteristic of the anisotropic magnetoresistive sensor 203 is nonlinear. When the magnetic field to be measured is very small, the slope of the transfer characteristic is close to zero, and the sensitivity of the magnetoresistive sensor 203 is extremely low.

[0026] After the bias magnet 2031 is added, a bias magnetic field is generated. The bias magnetic field can suppress temperature drift and improve the signal-to-noise ratio of the magnetoresistive sensor 203. When the magnetic field of the float 101 is close to the magnetoresistive sensor 203, when the magnetic field of the float 101 is less than or equal to the bias magnetic field of the bias magnet 2031, the slope of the transfer characteristic of the magnetoresistive sensor 203 is close to zero. At this time, the working point of the magnetoresistive sensor 203 is offset, and as the stroke of the float 101 increases, the magnetoresistive sensor 203 senses the increasing magnetic field of the float, and the slope of the transfer characteristic of the magnetoresistive sensor 203 increases. The sampling curve enters the linear region. When the sampling curve approaches the turning point, that is, when its sampling value reaches the maximum, the slope of the sampling curve with the bias magnetic field remains basically unchanged until the sampling is reversed after the turning point; thereby, the linear range of the magnetoresistive sensor 203 is increased, so that the addition of the bias magnet can increase the linear range that can be used by the magnetoresistive sensor 203.

[0027] In addition, the magnetic field strength of the bias magnet 2031 is between 45Gs-55Gs, while the magnetic field strength of the geomagnetic field is between 0.5Gs-0.6Gs. The magnetic field strength of the geomagnetic field is much smaller than the magnetic field provided by the bias magnet 2031, so the influence of the geomagnetic field can be ignored. Therefore, the use of magnetic bias technology can increase the linear measurement range of the anisotropic magnetoresistive sensor 203, and reduce the influence of the geomagnetic field on the flowmeter measurement. It is suitable for weak magnetic coupling and small flow metal tube float flowmeters to realize magnetic displacement electrical signal conversion, thereby realizing digital display of flow measurement and remote signal transmission.

[0028] In addition, in the description of the present invention, it should be noted that the terms "magnetic bias", "bias magnet", "magnetoresistive sensor", "geomagnetic field", "magnetic coupling", "magnetic field strength", etc. are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A metal tube float flowmeter using magnetic bias technology, comprising a metal tube float flowmeter body, characterized in that: The metal tube float flowmeter body comprises a measuring tube (1) and an indicator (2), and the measuring tube (1) and the indicator (2) are connected and fixed by screws; The measuring tube (1) comprises a float (101) and a cone tube, wherein a bullet-shaped metal structure (102) of a rod-shaped magnetic steel is built in the float (101); The indicator (2) comprises a metal shell (201), a window glass is embedded and fixed on the front side of the metal shell (201), a PCB board (202) is installed in the metal shell (201), the PCB board (202) is arranged vertically parallel to the measuring tube (1), the front side of the PCB board (202) is electrically connected to two magnetoresistive sensors (203), the magnetoresistive sensors (203) are mounted on the front side of the PCB board (202), and the two magnetoresistive sensors (203) are both located at the measuring tube (1). On the left side of the tube (1), the two magnetoresistive sensors (203) are installed in opposite directions, a bias magnet (2031) is attached to the front side of the magnetoresistive sensor (203), a plurality of pins are provided on the magnetoresistive sensor (203), the bias magnet (2031) is attached to the position between the gap between pins 3 and 4 and between pins 5 and 6 of the corresponding magnetoresistive sensor (203), and the N pole of the magnetic pole direction of the bias magnet (2031) corresponds to the gap between pins 3 and 4, and the S pole corresponds to the gap between pins 5 and 6.

2. A metal tube float flowmeter using magnetic bias technology according to claim 1, characterized in that: The outer side of the PCB board (202) is sealed with a plastic shell, and the rear side of the plastic shell is fixedly connected to the rear inner wall of the metal shell (201).

3. The metal tube float flowmeter using magnetic bias technology according to claim 1, characterized in that: The material of the bias magnetic steel (2031) is iron-chromium-cobalt, the magnetic field strength of the bias magnetic steel (2031) is between 45Gs-55Gs, and the fixed size of the bias magnetic steel (2031) is 2x1x0.5mm.

4. The metal tube float flowmeter using magnetic bias technology according to claim 1, characterized in that: The magnetoresistive sensor (203) has four identical sensing units built therein, the four sensing units form a Wheatstone bridge, the bridge differential output is proportional to sin2θ, and its output curve is approximately a sine curve.

5. The metal tube float flowmeter using magnetic bias technology according to claim 1, characterized in that: The measuring tube (1) is used for measuring a pipeline through which a medium flows.

6. The metal tube float flowmeter using magnetic bias technology according to claim 1, characterized in that: The magnetoresistive sensor (203) is a Honeywell HMC1501 magnetoresistive sensor.

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