CN100416230C - Magnetic-label fluid flowmeter - Google Patents

Abstract

A magnetic fluid flow meter of magnetic labeling type is prepared as series-connecting modified nylon pipe on path of magnetic pulp transportation and winding two wire coils on nylon pipe intensively, setting one of two coils to be magnetic charge coil at upstream and another to be magnetic detection coil at down stream, connecting two said coils in serial mode, loading rectangular pulse on magnetic charge coil at equal time interval and sending magnetic detection signal to analysis-processor for carrying out calculation and display by magnetic detection coil.

Description

Magnetic-label fluid flowmeter

Technical field

The present invention relates to a kind of on-line continuous and measure the measurement instrument of magnetic fluid flow, flow velocity.

Background technology

In type selecting, find: still do not have the flowmeter that is suitable for measuring ultra-fine broken section and chats section flow of slurry at present at the flow measurement instrument of iron ore mine wet separation flow of slurry.Flow of slurry has following characteristics: a, flow of slurry is a solid, liquid two-phase stream; B, flow of slurry have magnetic, and the magnetic power changes at any time with the change of breeze concentration and breeze character; C, flow of slurry particularly wherein ultra-fine broken section existence surpass the big build solid particle of Ф 3mm; Big, solid particle the usually hardness of d, flow of slurry flow velocity is very high so have a very strong abrasive action.Above characteristics in view of flow of slurry, what most probable was applicable to the flow measurement of iron ore slurry is following three kinds of flowmeters: 1, Doppler ultrasonic flow meter: this type of flowmeter can be measured the flow of solid, liquid two-phase stream, and be not subjected to the fluid effect of magnetic influence, but the concentration that requires solid matter usually is below 100ppm, so and be not suitable for to transport the high concentration flow of slurry that breeze is a purpose.2, (be called for short: the Ke Shi flowmeter): the Ke Shi flowmeter can be measured solid, liquid two-phase stream to curry sharp mass flowmeter difficult to understand, be not subjected to the fluid effect of magnetic influence, but can produce very big measuring error during the tube wall of the solid particle in the fluid, the particularly sensing element-vibrating tube of larger particles bump Ke Shi flowmeter, vibrating tube is generally thin-wall metal pipe simultaneously, its abrasion resistance is limited, so also inapplicable.3, electromagnetic flowmeter: electromagnetic flowmeter is successfully applied to the fine ore transportation section of iron ore slurry stream.But and be not suitable for the flow measurement of the flow of slurry of ultra-fine broken section and chats section.

Summary of the invention

Owing to do not have special at present as yet at magnetic fluid, the especially flowmeter of solid, liquid two-phase magnetic flow, purpose of the present invention will be filled up this technological gap exactly, a kind of magnetic-label fluid flowmeter is provided, realize that iron ore slurry transports the measurement of flow, particularly solve the measurement of ultra-fine broken and chats ore pulp volumetric flow rate and flow velocity, realize the volumetric flow rate of all magnetic fluids and the measurement of flow velocity.

Technical scheme of the present invention is achieved like this: a kind of magnetic-label fluid flowmeter, be characterized in: on magnetic ore pulp transport path, be serially connected with the good modified MC nylon pipe 4 of anti-wear performance, closely on nylon tube 4 be wound with two lead loop, one is the coil 3 that magnetizes, another is a magnetic pick-up coil 2, two coil serial arrangement, the coil that magnetizes is in the upstream, and magnetic pick-up coil is in the downstream; Constant duration loads rect.p. on the coil that magnetizes, and magnetic pick-up coil will be examined magnetic signal by signal transmssion line and deliver to analysis processor and calculate demonstration.

The present invention is suitable for measuring the flow of ultra-fine broken section and chats section flow of slurry, can online direct measurement, and the precision high level error is little.

Description of drawings

Fig. 1 is the principle schematic of the embodiment of the invention 1.

Fig. 2 is the spatial distribution map of magnetic induction density in the magnetic field that coil produces of magnetizing of the embodiment of the invention 1.

Fig. 3, Fig. 4 are the corresponding time relationship figure of the magnetize pulse and the magnetic pick-up coil induction electromotive force of the embodiment of the invention 1.

Fig. 5 is the principle schematic of the embodiment of the invention 2.

Fig. 6 is that the magnetic strength of the coil that magnetizes of the embodiment of the invention 2, the cylinder that magnetizes distributes, the spatial relationship figure of two magnetic pick-up coils.

Fig. 7 is the time chart of the pulse of magnetizing of the embodiment of the invention 2.

Fig. 8 is the corresponding time relationship figure of the preceding magnetic pick-up coil induction electromotive force of the embodiment of the invention 2.

Fig. 9 is the corresponding time relationship figure of the back magnetic pick-up coil induction electromotive force of the embodiment of the invention 2.

---flow of slurry is to 2---magnetic pick-up coil 3---coil 4 magnetizes---MC nylon pipeline 5---preceding magnetic pick-up coil 6---back magnetic pick-up coil among the figure 1

Embodiment

Fundamental measurement principle of the present invention is that the magnetic fluid that flows is realized magnetizing and examining two processes of magnetic, and specific implementation has following two kinds of embodiments:

Embodiment 1: unicoil inspection magnetic mode

From Fig. 1 as seen, arrange two lead loop on magnetic ore pulp transport path, one is the coil 3 that magnetizes, and another is 2, two coil serial arrangement of magnetic pick-up coil, and the coil that magnetizes is in the upstream, and magnetic pick-up coil is in the downstream.Two coils are close to be around on the good modified MC nylon pipe 4 of anti-wear performance, and the loop length of the coil that magnetizes is with to transport pipe caliber and flow velocity relevant.The length of magnetic pick-up coil is at below 0.1 times of the coil that magnetizes.Two coils are generally with the enameled wire coiling of 0.3mm.Constant duration loads rect.p. on the coil that magnetizes, and the time interval of two pulses is relevant with the flow rates of ore pulp, can adjust continuously, set.Magnetic pick-up coil will be examined magnetic signal by signal transmssion line and deliver to analysis processor and calculate demonstration.The size of charging current is strong and weak relevant with flow velocity with the magnetic of ore pulp, can test adjustment, set.The interval of centimetre magnitude can be arranged or leave to two coils continuously.

Logical going up after the electric current, the space distribution of the magnetic induction density in the magnetic field that coil produces of magnetizing as shown in Figure 2.The maximum position of magnetic induction spatial variations rate appears at two intersection point P of tube's axis and magnetic strength distribution curve ₁And P ₂On, these two intersection points and they the magnetize end face distance of coil of place side separately are made as Δ, and two end faces of coil that magnetize are respectively L to the distance of magnetic pick-up coil center line ₁And L ₂Be carried in current pulse width on the coil that magnetizes in the millisecond magnitude, this pulse signal can inspire induction electromotive force at once on magnetic pick-up coil, and this electromotive force obtains two opposite maximum value of direction respectively in two moment on the upper and lower edge of pulse of magnetizing.The magnetic fluid that is magnetized is cylindric, and Distribution of Magnetic Field in this cylinder and the Distribution of Magnetic Field of Fig. 2 have strong positive correlation.Consider that this cylinder at the uniform velocity passes through magnetic pick-up coil, because the size of induced electromotive force is directly proportional with the flux change rate, therefore working as the forward and backward magnetic induction rate of change of cylinder maximum is position P ₁And P ₂The place constantly can produce two opposite induced electromotive force maximum value of direction by two of magnetic pick-up coil.

The moment of two electromotive force peak values that the pulse of magnetizing excites on magnetic pick-up coil is determined to be known quantity by the pulsewidth that magnetizes, so by the measurement ore pulp cylinder P that magnetizes ₁And P ₂The place by two electromotive force peak values that magnetic pick-up coil excited, two positions just can calculate corresponding flow time, constantly because the distance L of two end faces of coil to the magnetic pick-up coil center line that magnetize ₁And L ₂Known, just can calculate the flow velocity of ore pulp in view of the above.

Fig. 3, Fig. 4 have provided the corresponding time relationship of magnetize pulse and magnetic pick-up coil induction electromotive force, and cylinder P wherein magnetizes ₁The distance that the position arrives the magnetic pick-up coil center line is L ₁+ Δ, P ₂Reach is L ₂-Δ (see figure 2), and the corresponding time is respectively τ ₁And τ ₂

$\left\{\begin{array}{c}{\mathrm{\τ}}_1=t_2-t_0\\ {\mathrm{\τ}}_2=t_{3-t_1}\end{array}\right.----\left(1\right)$

P ₁And P ₂Movement velocity be respectively:

$\left\{\begin{array}{c}{V}_1=\frac{L_1+\mathrm{\&Delta;}}{{\mathrm{\&tau;}}_1}\\ {\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="C20051009472700081.png"\; state="\{\{state\}\}">V</figure-callout>}}_2=\frac{L_2-\mathrm{\&Delta;}}{{\mathrm{\&tau;}}_2}\end{array}\right.---\left(2\right)$

Because V ₁=V ₂=V analysis mode (2) obtains:

$V=\frac{(L_1+\mathrm{\&Delta;})+(L_2-\mathrm{\&Delta;})}{{\mathrm{\&tau;}}_1+{\mathrm{\&tau;}}_2}=\frac{L_1+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="C20051009472700081.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}{{\mathrm{\&tau;}}_1+{\mathrm{\&tau;}}_2}---\left(3\right)$

It should be noted that decision P ₁And P ₂The factor of position is in fact very complicated, so Δ can't measure, so the result of formula (3) is important and easily.

Embodiment 2: the twin coil detection mode

This scheme has been used two magnetic test coils, is provided with back magnetic pick-up coil 6 on the left side of preceding magnetic pick-up coil 5, and principle is illustrated as Fig. 5.The magnetic strength of coil, the cylinder that magnetizes of magnetizing distributes, the spatial relationship of two magnetic pick-up coils is seen Fig. 6.Fig. 7, Fig. 8, Fig. 9 are the corresponding time relationship figure of pulse and forward and backward magnetic pick-up coil induction electromotive force of magnetizing.

The principle of two magnetic pick-up coil detection schemes is utilized the cylinder P that magnetizes exactly ₁And P ₂The room and time relation of one in front and one in back two the electromotive force peak values that pass through former and later two magnetic pick-up coils respectively and excited calculates the flow velocity of magnetic fluid, herein only to P ₁Pass through to example and discuss.

By Fig. 6, Fig. 7, Fig. 8, Fig. 9 as can be known: τ ₁=t ₂-t ₀Be P ₁The time of magnetic pick-up coil center line before passing through, travel distance is (L ₁+ Δ).τ ₃=t ₄-t ₀Be P ₁Pass through the time of back magnetic pick-up coil center line, travel distance is (L ₃+ Δ).Then flow rate of pulp is:

$V=\frac{({\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="C20051009472700071.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+\mathrm{\&Delta;})-(L_1+\mathrm{\&Delta;})}{{\mathrm{\&tau;}}_3-{\mathrm{\&tau;}}_1}=\frac{L_3-L_1}{{\mathrm{\&tau;}}_3-{\mathrm{\&tau;}}_1}---\left(4\right)$

Utilize formula (3) or formula (4) to obtain after the flow rate of pulp,, then can obtain the volumetric flow rate I of magnetic fluid for pipeline transportation and when being full-section pipe-flow:

I＝SV (5)

S in the formula (5) is a cross-sectional area in the conveying pipe.

Online direct measurement related in the design proposal only is time measurement, measurement range from 1 millisecond to the several seconds, the precision of considering existing embedded computing chip onboard clock can reach in tens of nanoseconds easily, so the time measurement error is controlled in 0.1% easily.

Claims (2)

1. magnetic-label fluid flowmeter, it is characterized in that: on magnetic ore pulp transport path, be serially connected with the good modified MC nylon pipe (4) of anti-wear performance, go up close coil that magnetizes (3) and the magnetic pick-up coil (2) of being wound with at nylon tube (4), magnetize and the magnetic pick-up coil serial arrangement, magnetize coil in the upstream, and magnetic pick-up coil is in the downstream; Constant duration loads the rect.p. electric current on the coil that magnetizes, and magnetic pick-up coil will be examined magnetic signal and deliver to analysis processor by signal transmssion line and calculate demonstration.

2. a kind of magnetic-label fluid flowmeter according to claim 1 is characterized in that: described magnetic pick-up coil is made of preceding magnetic pick-up coil (5) and the back adjacent arrangement of magnetic pick-up coil (6) two lead loop.

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