CN212458485U

CN212458485U - Electromagnetic flowmeter of high-frequency and low-power-consumption excitation system

Info

Publication number: CN212458485U
Application number: CN202021807603.XU
Authority: CN
Inventors: 刘克金
Original assignee: Shenyang Lanshen Instrument Co ltd
Current assignee: Shenyang Lanshen Instrument Co ltd
Priority date: 2020-08-26
Filing date: 2020-08-26
Publication date: 2021-02-02
Anticipated expiration: 2030-08-26

Abstract

An electromagnetic flowmeter of a high-frequency and low-power consumption excitation system and an excitation method thereof belong to the technical field of electromagnetic flowmeters. A group of a plurality of magnetic memory monomers are respectively arranged at the upper part and the lower part outside the measuring tube. Each magnetic memory unit is wound with an excitation coil. Each group of the plurality of magnetic memory cells are arranged in a matrix manner. An excitation current pulse I is supplied to the excitation coil at the excitation start 1/2 cycle. Because the number of turns of the excitation coil wound on each magnetic memory monomer is small, the inductance value of the excitation coil is small, and the excitation current climbs quickly. Therefore, the excitation frequency can be increased in multiples, the measurement response speed of the electromagnetic flowmeter is further increased, and low power consumption of the excitation system of the electromagnetic flowmeter is realized because the excitation current is pulse current instead of continuous constant current.

Description

Electromagnetic flowmeter of high-frequency and low-power-consumption excitation system

Technical Field

The utility model belongs to the technical field of the electromagnetic flowmeter, a high frequency, low-power consumption excitation system's electromagnetic flowmeter and its excitation method are related to, and the electromagnetic flowmeter can be used to the real-time measurement fluid flow, the utility model discloses utilize a unique excitation mode, realized quick response, the design of the electromagnetic flowmeter of low-power consumption.

Background

The electromagnetic flowmeter is an instrument for measuring the volume flow of conductive liquid by utilizing the working principle of Faraday's law of electromagnetic induction. Namely, the conductive liquid is regarded as a conductor, and the flow of the fluid is regarded as that the conductor makes a motion of cutting magnetic lines. And then the flow velocity, the flow and the like of the conductive fluid are measured by the law of electromagnetic induction. The principle is shown in figure 1.

1 is a measuring tube and 2 is a detecting electrode.

When the conductive liquid moves along the measuring tube 1 in the direction perpendicular to the alternating magnetic field and the magnetic lines, the conductive liquid cuts the magnetic lines to generate an induced potential E. A pair of detection electrodes 2 are mounted on the wall of the measuring tube 1 perpendicular to the axis of the measuring tube 1 and the magnetic field lines of the magnetic field, and this induced potential E is detected.

If the induced potential is E, then there are:

E＝BVD ⑴。

in the formula: b … magnetic induction.

The distance between the electrodes D … is equal to the inner diameter of the measuring tube 1;

v … measures the average flow velocity of the measured fluid in the tube 1 over the cross section.

In the formula, a magnetic field B is constant, and D is a constant, so that the induced potential E is in direct proportion to the flow velocity V of the measured fluid. The relationship between the instantaneous volume flow Q and the flow velocity V through the measuring tube 1 in cross section is:

the method has the advantages that:

in the formula: k … instrument constant.

E is generally called flow signal, the flow signal is input into a converter, and is processed to output a 4-20 mA current signal and a pulse (or frequency) signal which are in direct proportion to the flow, and the flow can be recorded and adjusted.

In the application field of the electromagnetic flowmeter, the requirements of quick response and low power consumption of the measurement of the electromagnetic flowmeter are frequently met, such as electromagnetic flow meters for some canning industry (e.g. beer) applications, require a fast start-stop response, which would otherwise affect the accuracy of the canned volume measurement, and there are also some slurry measurement applications, because the measuring medium is liquid-solid two-phase flow, the electromagnetic flowmeter is required to have higher detection frequency in order to meet the requirement of measuring precision, for the electromagnetic flow meters in some special application fields, a high-frequency excitation system is required, and other application fields (such as petroleum and field operation) requiring battery power supply require low power consumption of the electromagnetic flow meter, while the excitation system occupies most of the power consumption of the electromagnetic flow meter, therefore, how to reduce the power consumption of the excitation system is the key point for solving the problem of the power consumption of the electromagnetic flowmeter.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a high frequency, low-power consumption excitation system's electromagnetic flow meter, another object of the utility model is to provide its excitation method. The design method of high-frequency and low-power consumption excitation system adopts the excitation system with series magnetic memory monomer wound around the excitation coil to produce the synthetic magnetic field with magnetic induction intensity of B so as to implement the design goal of high-frequency and low-power consumption excitation system.

The technical scheme is as follows:

the utility model provides a high frequency, low-power consumption excitation system's electromagnetic flowmeter, measures the inside wall of pipe and sets up a pair of detection electrode and excitation system including surveying buret, and excitation system includes two sets of magnetism memory monomer and a plurality of excitation coil.

The technical key points are as follows:

a group of a plurality of magnetic memory monomers are respectively arranged on the upper side and the lower side of the measuring tube. Each magnetic memory unit is wound with an excitation coil.

Each group of the plurality of magnetic memory cells are arranged in a matrix manner.

Each magnetic memory cell is in the shape of a cylinder. The cylinder axis of the magnetic memory cell is arranged along the radial direction of the circular cross section of the measuring tube.

The magnetic memory monomer is made of Wangan magnetic memory material.

As shown in part b of fig. 4.

Excitation system of common electromagnetic flowmeterThe current I is introduced into the excitation winding group with the number of rectangular turns N, and a magnetic field with the magnetic induction intensity B in the vertical direction is generated by Faraday's electromagnetic induction theorem (as shown in a part B in figure 2). The exciting current I is equivalent to a constant current source I_SAnd R_S，(I_SIs a constant current source, R_SIs the dynamic internal resistance of the current source 3 of the excitation system, R is the equivalent resistance of the original excitation coil 4, and L is the inductance of the original excitation coil 4).

The general exciting current I is a standby square wave constant current of 125mA-250mA, the number of winding turns is about 1000 turns, the general exciting frequency cannot be very high (generally 3.2Hz-33Hz) due to the limitation of the self inductance of the exciting coil, otherwise the exciting current does not reach the constant current in the sampling measurement section, and the measurement precision (as part B in figure 3) is influenced, so that the inductance is reduced on the premise of obtaining the same magnetic induction intensity B, the 'climbing' time period is further reduced, namely, the time constant tau of the exciting coil is reduced, (and the time constant tau of the exciting coil is reduced (but the winding turns are about 1000 turns)

In general R_S> R, i.e.

) The key point for improving the frequency of the excitation system is.

An excitation method of an electromagnetic flowmeter of a high-frequency low-power excitation system comprises the following steps: the method is characterized by comprising the following steps:

in terms of increasing the excitation frequency: an excitation system formed by a series of magnetic columns is adopted to generate a composite magnetic field with the same strength B.

Because each magnetic pole is wound by the excitation coil with few turns, the inductance of the excitation coil is small, and the time constant is small

In general R_S＞＞R_ilI.e. by

τ_il＜τ(τ_ilFor the time constant, R, of the field coil of each column_STo encourageDynamic internal resistance R of current source of magnetic system_ilWinding internal resistance, L, of the field coil for each pole_ilThe inductance of the field coil is wound for each pole) so that the field current 'climbs' quickly. The excitation frequency can be increased by a multiple (see part a in fig. 4), thereby increasing the measurement frequency of the electromagnetic flowmeter.

In the aspect of reducing the power consumption of the excitation system:

because the magnetic pillar is made of the Wang 'an magnetic memory material, the hysteresis curve of the magnetic pillar is close to a rectangle (as part a in figure 5), an excitation current pulse I (as part b in figure 5) can be supplied to the excitation coil at the excitation starting 1/2 period, the excitation magnetic field is maintained by the magnetic' memory 'characteristic of the Wang' an magnetic memory, and the excitation coil does not continuously apply current but a current pulse with a narrow width in the whole excitation period, so that the power consumption of an excitation system is greatly reduced.

The advantages are that:

because the number of turns of the excitation coil wound on each magnetic memory monomer (magnetic column or magnetic bead) is small, the inductance of the excitation coil is small, and the 'climbing' of the excitation current is fast. Therefore, the excitation frequency can be increased by times (as part a in fig. 4), and the measurement response speed of the electromagnetic flowmeter is further increased, and the power consumption of the excitation system is greatly reduced because the current applied to the excitation coil is not continuous current but current pulse with a narrow width. And because the exciting current is pulse current rather than continuous constant current, the low power consumption of the exciting system of the electromagnetic flowmeter is realized.

Drawings

Fig. 1 is a schematic diagram of an electromagnetic flowmeter.

Fig. 2 is a schematic diagram of the circuit principle and structure of the exciting coil.

Fig. 3 is a waveform diagram of the excitation voltage U, the current I, and the magnetic induction B.

Fig. 4 is a schematic diagram of magnetic pole distribution, excitation voltage U, excitation current I, and magnetic induction B of the magnetic poles.

FIG. 5 is a diagram of the hysteresis curve, the excitation current pulse I and the magnetic induction B of the magnetic memory material.

Fig. 6 is a front sectional view of the present invention.

Fig. 7 is a top view of the present invention.

The device comprises a measuring pipe 1, a detection electrode 2, an excitation system current source 3, a primary excitation coil 4, a magnetic memory monomer 5 and an excitation coil 6.

Detailed Description

Example 1

An electromagnetic flowmeter of a high-frequency and low-power consumption excitation system comprises a measuring tube 1, wherein a pair of detection electrodes 2 are arranged on the inner wall of the measuring tube 1, and the pair of detection electrodes 2 are symmetrically distributed at two ends of the diameter of a circular section.

The excitation system comprises two groups of magnetic memory units 5 and a plurality of excitation coils 6.

A group of a plurality of magnetic memory monomers 5 of an excitation system are respectively arranged at the upper side and the lower side outside the measuring pipe 1. Each magnetic memory cell 5 is wound with an excitation coil 6.

Each magnetic memory cell 5 is cylindrical in shape.

A pair of detection electrodes 2 are located on the measurement pipe 1 on the left and right sides in the horizontal direction.

The cylinder axis of the magnetic memory cells 5 is arranged in the radial direction of the circular cross section of the measuring tube 1.

Each group of the plurality of magnetic memory cells 5 is arranged in a matrix manner, for example, n rows and m columns.

Each magnetic memory cell 5 is wound with an excitation coil 6.

Each set of a plurality of magnetic memory cells 5 is supported by a corresponding support.

Example 2

An excitation method of an electromagnetic flowmeter of a high-frequency low-power excitation system comprises the following steps:

the excitation coil 6 is supplied with an excitation current pulse I during the excitation start 1/2 period.

The magnetic memory unit 5 is made of a magnetic memory material, such as Wangan magnetic memory material. Its hysteresis curve is close to rectangular. An excitation current pulse I (as shown in part b of fig. 5) can be applied to the excitation system at the excitation start 1/2 period, the excitation magnetic field is maintained by the magnetic memory material and the magnetic "memory" characteristic, and the current is not continuously applied but is a current pulse with a narrow width in the whole excitation period, so that the power consumption of the excitation system is greatly reduced.

By the method, an excitation system with higher excitation frequency and lower power consumption compared with the existing electromagnetic flowmeter can be obtained, and the requirements of canned and slurry type electromagnetic flowmeters with low power consumption on high-frequency low-power consumption excitation systems are met. Low power consumption of the magnetic system.

Claims

1. An electromagnetic flowmeter of a high-frequency and low-power consumption excitation system comprises a measuring tube (1), wherein the inner wall of the measuring tube (1) is provided with a pair of detection electrodes (2) and an excitation system, and the excitation system comprises two groups of magnetic memory monomers (5) and excitation coils (6) of the excitation system; the method is characterized in that:

a group of a plurality of magnetic memory monomers (5) of an excitation system are respectively arranged at the upper side and the lower side outside the measuring pipe (1); each magnetic memory monomer (5) is wound with an excitation coil (6).

2. An electromagnetic flowmeter for a high frequency, low power exciter system according to claim 1, wherein: each group of the plurality of magnetic memory cells (5) are arranged in a matrix manner.

3. An electromagnetic flowmeter for a high frequency, low power exciter system according to claim 1, wherein: each magnetic memory monomer (5) is in a cylindrical shape; the cylinder axis of the magnetic memory unit (5) is arranged along the radial direction of the circular section of the measuring tube (1).