CN1610763A - Apparatus for controlling coating weight on strip in continuous galvanizing process - Google Patents

Abstract

The present invention relates to an apparatus for controlling coating weight on a steel strip in a continuous hot dip galvanizing process, in which the coating weight is controlled through air wiping after the steel strip passes through a molten zinc coating bath. More particularly, the apparatus according to the present invention keeps the steel strip equidistant from each air knife, uniformly distributes a spray pressure of the air knives in a widthwise direction of the steel strip, and minimizes variation in coating weights on both surfaces of the steel strip. Furthermore, when two steel strips that are different in thickness are continuously hot dip galvanized, the apparatus according to the present invention predicts the movement of the passing line of the steel strips and accurately controls the positions of the air knives. As a result, product deficiencies such as insufficient coating can be reduced and zinc loss due to excess coating can be minimized.

Description

The device of the coating weight in continuous zinc coating is handled on the control steel band

Technical field

The present invention relates to the device of the coating weight on the control steel band in a kind of continuous hot-dipping galvanizing processing, wherein after steel band passes through zinc liquid coating bath, wipe the control coating weight by air.The present invention be more particularly directed to the device of the coating weight on the control steel band in such continuous hot-dipping galvanizing processing, wherein because under predetermined pressure, the airstream of on the steel band that has passed zinc liquid coating bath, jetting, optimized steel band and control coating weight air knife between distance, and/or the jetting pressure of air knife, thereby make the difference minimum of the coating weight that actual coating weight and user order goods.

Background technology

General using coating is handled to be provided anticorrosive and steel band aesthetic appearance.As the example that representational coating is handled, the hot dip process that has steel band to pass through molten metal is handled and with the electroplating processes of electrolytic solution.

It is that molten metal is attached to treating processes on the steel band both side surface of the coating bath by the deposite metal that hot dip process is handled.This needs evenly to control the independent equipment of the coating weight on the steel band.

The conventional coating weight that uses on the air erasure reason control steel band.By passing under certain air pressure of air knife, the airstream of on two surfaces of the steel band that passes coating bath, jetting, this processing can be controlled the coating weight of metal.

It is important keeping the homogeneous coating weight on the steel band in galvanizing is handled.For this reason, need control as the steel band of most important factor and the jetting pressure of distance between the air knife and air knife in the air erasure reason.

Fig. 1 is to use the synoptic diagram of the prior art continuous hot-dipping equipment of air erasure reason.When steel band 1 passed through zinc liquid coating bath 2 via deflector roll 5, zinc liquid was attached on the both side surface of steel band 1.Steel band by zinc liquid coating bath 2 is transported to the space that limits by between first and second air knives 3 and 4 on the upside that is installed in zinc liquid coating bath.At this moment, on the side of the front and back of steel band 1, the jet airstream of on steel band predetermined pressure of air knife 3 and 4, thereby, wipe too much zinc liquid and guarantee zinc liquid uniform distribution on steel band 1.In Fig. 1, the steric direction that symbol 6 expression limits between air knife 3 and 4 is by the stable roller of the steel band of zinc liquid coating bath 2, symbol 8 expressions be installed in air knife 3 and air line that 4 are connected in pressure regulator valve.

Handle with regard to the continuous hot-dipping galvanizing that above-mentioned use air is wiped, at the width (d) of steel band 1, the respective nozzle of the surface of steel band 1 and first and second air knives 3 and 4 must be parallel to each other.And, must be identical in the distance between the front side of the nozzle of first air knife 3 and steel band 1 with the distance between the rear side of second air knife 4 and steel band 1.

By the coating weight of the spatial steel band of qualification between first and second air knives 3 and 4, and the distance between first and second air knives 3 and 4 respective nozzles and steel band 1 increases inversely.For this reason, if the coating weight on the steel band 1 that distributes equably on steel band 1 width (d), then the respective nozzle of steel band 1 and first and second air knives 3 and 4 must remain parallel to each other.In addition, if identical with the coating weight on the steel band rear side, then must keep steel band and each air knife equidistant at the coating weight on the steel band front side.

Prior art uses feedback processing to be controlled at steel band 1 and first and second air knives 3 and 4 distance between each.That is, at first measure the coating weight of the width on the steel band (the spatial steel band that limits between promptly by air knife) at coating.Then, at these observed values not simultaneously, regulate the position of first and second air knives 3 and 4 with electric motor M1-M4.

But such prior art is handled, and in order to make the respective nozzle of steel strip surface and air knife parallel to each other, needs the plenty of time.For this reason, serious problem is, at width (d) the coating weight skewness one of steel band, or inequality at the coating weight of the front side of steel band and rear side.

Simultaneously, for for increase work efficiency will coating steel band continuous hot-dipping galvanizing connected to one another handle, the different steel band of thickness may be connected to each other.

Fig. 2 (a) and (b) be the synoptic diagram that continuous hot-dipping galvanizing is handled.When space by between first and second air knives 3 and 4, limiting of the welding portion P of different in conjunction with thickness two steel band 1a and 1b, act on steel band 1a and 1b owing to stablize roller 6, the traveling route of steel band is moved.

So mobile difference that causes distance between the distance between the steel band front side and first air knife 3 and the steel band rear side and second air knife 4 of the traveling route of steel band.As a result, the coating weight of the front side of steel band and rear side is different.

In order to overcome the problems referred to above, routinely, just at the welding portion of two steel bands different in conjunction with thickness by before the air knife, operator according to the direction of air knife regulate first and second air knives 3 and 4 between distance.Fully by behind first and second air knives 3 and 4, leaving the corresponding coating weight of coating weight transmitter (not shown) measurement on the side of the front and back of steel band of installing on about 100 meters rear positions of first and second air knives 3 and 4 at welding portion.Measure by this, determine to depend on that the coating weight on the side is poor before and after the mobile steel band that causes of steel band traveling route.Based on this difference, can control the distance between these two air knives gradually with feeding back.

But, at this moment, in order to make that the corresponding coating weight on the side equates to need the plenty of time before and after the steel band, thereby produce coated steel strips inferior.

Simultaneously, the continuous hot-dipping galvanizing that just uses air to wipe is handled, and when the speed of feed of the coating weight of the hope that changes steel band or steel band, must suitably regulate the air knife jetting pressure of air.

For this reason, operator according to the direction of air knife, regulate the jetting pressure of air knife according to the variation of the coating weight of the hope of the speed of feed of steel band and steel band.In addition, they also utilize the existing table that the setup pressure value of existing expression air knife changes along with the variation of steel band speed of feed.

But in this case, operator's adjusting may be inaccurate.When utilizing existing table, whenever air knife is overhauled, the air knife characteristic that all values on the table are coordinated to be modified is difficult, and can not realize rapid pressure control, thereby its practical application is worthless.

In a word, become minimum at the coating weight of hope and the difference between the actual coating weight, when the thickness of steel band and speed of feed change, must correctly change the setup pressure value of air knife in order to make.If change the setup pressure value of air knife improperly, then just frequent insufficient coating or the blocked up coating of taking place.For this reason, quality product variation.In addition, when coating was blocked up, the zinc liquid measure of use surpassed required amount, also causes additional consumption.

Summary of the invention

Therefore, in view of the above-mentioned problem of handling with the prior art galvanizing of air wiping, the present invention has been proposed, the purpose of this invention is to provide a kind of device, it can be controlled at the coating weight of continuous hot-dipping layer processing on middle steel band, and is wherein parallel to each other at the width steel band and the nozzle of steel band, and it is equidistant that steel band and each nozzle keep, make the spatial center that steel band limits between air knife, and parallel with each nozzle.

Another object of the present invention provides a kind of device, it can wipe coating weight on the steel band of controlling the continuous hot-dipping galvanizing processing by enough air, wherein according to the coating weight or the speed of feed of the hope of steel band, suitably regulate the jetting pressure of air knife, make difference minimum between the coating weight that is attached to actual coating weight on the steel band and hope.

Another object of the present invention provides a kind of device, coating weight on the steel band during the enough air wipings of its energy control continuous hot-dipping galvanizing is handled, wherein when space by between air knife, limiting of the connection of the steel band of two different thickness, rely on the thickness of steel band to change, moving of the traveling route of prediction steel band, regulate the distance between steel band and the air knife then, make the coating weight difference minimum of front and back sides of steel band.

According to the present invention, by provide a kind of control continuous hot-dipping galvanizing handle on the steel band device of thickness of coating realized above-mentioned and other purposes, in described device, first and second air knives are set, airstream by winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath, coating weight on the control steel band, described device comprises:

Multiple spurs is from measuring apparatus, and the center that it is installed in back shaft is separated from each other predetermined distance, and the described back shaft and second air knife are measured the distance of steel band and described air knife in a straight line;

Distance adjusting means, when moving forward and backward each two ends of first and second air knives, it regulates the distance of first and second air knives each and steel band;

Width of measuring device, it measures the width of steel band; With

The apparatus for adjusting position of distance-measuring device, it makes distance-measuring device can be positioned at the center of the width of steel band according to the measurement result of width of measuring device.

Described width of measuring device can be made of first and second width sensors, they each be included in light emission part and the light receiving part on back shaft on first air knife, described back shaft be installed on the relative end of first and second air knives with second air knife on a straight line, partly launch the light time at light emission, by the light that light receiving part is surveyed, transmitter is determined the position and the width of steel band.

Described apparatus for adjusting position can be by constituting with lower device: the position adjustments electric motor, and it moves described back shaft along the width of steel band, and wherein the light receiving part and the multiple spurs of first and second width sensors are installed on the described back shaft from measuring apparatus; Drive the position controller for motor of described position adjustments electric motor; With first logical block, it calculates the movement value of described position adjustments electric motor, and the value input motor position control that will calculate then is so that the light quantity of surveying on each light receiving part of first and second width sensors equates.

First logical block can produce the movement value of distance-measuring device as follows:

ΔGc＝(Nws-Nds)×Pss

Wherein, Δ Gc is the movement value of distance-measuring device, and Nws is the number of photometry photorectifier in first width sensor, and Nds is the number of photometry photorectifier in second width sensor, and Pss is the distance between the photorectifier.

Distance-measuring device can be made of three or more rang sensor spaced apart a predetermined distance.

Distance adjusting means can be by constituting with the lower section; Four or a plurality of distance adjustment electric motor, when described electric motor was connected to each two ends of first and second air knives, described electric motor moved forward and backward along the steel band direction; Second logical block, it utilizes by the steel band of rang sensor measurement and the distance between second air knife and calculates the movement value at first and second each two ends of air knife, thereby steel band is kept equidistant with each air knife, and parallel with each air knife; With four or a plurality of position controller for motor, their distance adjustment electric motor are as far as from each the movement value at two ends of first and second air knives of second logical block output.

Second logical block can be with any as initial point, limits the X-Y coordinate plane that the Y-axis of the X-axis of the front/rear travel direction of first and second air knives and width of steel band direction is crossed over; And will be following formula at the curve representation of the steel band on the described X-Y coordinate plane:

S(x)：y＝ax ²+bx+c

(wherein, S (x) is the curvilinear function of the steel band on the X-Y coordinate plane, and a, b and c are the coefficients of S (x)); To change the X-Y coordinate figure into from a plurality of observed values that measuring apparatus obtains from multiple spurs; In X-Y coordinate figure substitution function S (x), obtain coefficient a, b and c; With the formula below S (x) substitution that obtains:

$\mathrm{\ΔY}=\frac{[{\∫}^W(S\left(x\right)-L_T\left(x\right))\mathrm{dx}-{\∫}^W(L_B\left(x\right)-S\left(x\right))\mathrm{dx}]}{2W}$

(wherein, Δ Y represents the average movement value of first and second air knives, and W represents the width size by the steel band of width sensor detection, L _T(x) linear equation of the expression first air knife nozzle, and L _B(x) linear equation of the expression second air knife nozzle), thus obtain the average movement value Δ Y of first and second air knives; Calculate the movement value Δ Yds and the Δ Yws of two ends of first and second air knives with following formula:

$\mathrm{\ΔYds}=\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{M}{G_{\mathrm{ss}}},$ $\mathrm{\ΔYws}=-\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{(L-M)}{G_{\mathrm{ss}}}$

(wherein Δ Yds is the movement value of an end of first and second air knives, Δ Yws is the movement value of the other end of first and second air knives, M be multiple spurs from the distance-measuring device at the center in the middle of the measuring apparatus and with distance adjusting means that an end of second air knife is connected between slant range, L is the distance between two distance adjusting means on the two ends of second air knife); Calculate each the final movement value Δ Y1 at two ends of first and second air knives with following formula then, Δ Y2, Δ Y3 and Δ Y4:

ΔY1＝-ΔY-ΔYws

ΔY2＝-ΔY-ΔYds

ΔY3＝ΔY+ΔYws

ΔY4＝ΔY+ΔYds

(wherein, Δ Y1 is the final miles of relative movement of an end (WS) of first air knife, the final miles of relative movement of the other end (DS) of Δ Y2 first air knife, Δ Y3 is the final miles of relative movement of an end (WS) of second air knife, Δ Y4 is the final miles of relative movement of the other end (DS) of second air knife).

According to a further aspect in the invention, a kind of device that continuous hot-dipping galvanizing is handled the coating weight on the steel band that is used for controlling is provided, wherein be provided with first and second air knives, airstream by winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath, coating weight on the control steel band, described device comprises:

Apparatus for adjusting position is regulated the position of first and second air knives;

The welding portion determinator is surveyed the change location of the welding portion that two steel bands that thickness in the zinc liquid coating bath is different combine;

Distance-measuring device is used to measure the distance between second air knife and the steel band;

Miles of relative movement prediction logic device, according to the thickness information of steel band, the movement value of the variation in thickness of the steel band of steel band by calculating the front and the welding back on it and the traveling route of steel band calculates each miles of relative movement of first and second air knives;

Miles of relative movement is measured logical unit, utilizes the steel band measured by distance-measuring device and the distance between second air knife, calculate welding portion by preceding and pass through after the movement value of steel band traveling route, calculate each miles of relative movement of first and second air knives;

The parameter correction device, the parameter that is used to proofread and correct miles of relative movement prediction logic device is so that the miles of relative movement predicted in miles of relative movement prediction logic device of compensation and measure error between the miles of relative movement of measuring in the logical unit in miles of relative movement;

Shifter, it is selected between the miles of relative movement of first and second air knives output of miles of relative movement prediction logic device and the output of miles of relative movement measurement logical unit, then selected miles of relative movement value is applied to apparatus for adjusting position; With

Switch control unit, change location according to the welding portion of surveying by the welding portion determinator, except before welding portion is by the first and second two air knives and after the scheduled time in apply the output valve of miles of relative movement prediction logic device to apparatus for adjusting position, apply the output valve that miles of relative movement is measured logical unit to apparatus for adjusting position.

Miles of relative movement prediction logic device can to following formula input front/back steel band each thickness and the thickness difference between them:

$\hat{S}={\mathrm{\αT}}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}+\mathrm{\β\ΔT}$

(wherein,

Be the prediction movement value of traveling route, T ₁Be the thickness of front steel band, Δ T is the thickness difference between front steel band and the back steel band, α and β are the predictor variablees), thus the prediction movement value of steel band traveling route calculated, generate each prediction miles of relative movement of first and second air knives according to the movement value of traveling route then.

Described miles of relative movement is measured the distance value that logical unit can receive the measurement between front/back steel band each and second air knife from described distance-measuring device, then with the actual movement value of the traveling route of following formula calculating steel band:

S＝(D ₂-D ₁)-(P ₂-P ₁)

(wherein, S is the actual movement value of traveling route, D ₁Be the distance between steel band and second air knife in front, D ₂Be by the distance between the back steel band and second air knife, P at welding portion ₁Be the position that welding portion passes through preceding second air knife, and P ₂Be the position of second air knife after welding portion passes through).

Described parameter correction device can be according to the operating parameters of the described miles of relative movement prediction logic of following formula correction device;

$\mathrm{\α}(t+1)=\mathrm{\α}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\α}}\frac{\∂(S-\hat{S})}{\∂\mathrm{\α}}=\mathrm{\α}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\α}}{T}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}$

$\mathrm{\β}(t+1)=\mathrm{\β}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\β}}\frac{\∂(S-\hat{S})}{\∂\mathrm{\β}}=\mathrm{\β}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\β}}\mathrm{\ΔT}$

(wherein γ alpha, gamma β is the scale-up factor of knowing (learning rate) of α and β.

According to a further aspect in the invention, a kind of device of controlling the coating weight on the steel band in the continuous hot-dipping galvanizing processing is provided, wherein be provided with first and second air knives, airstream by winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath is controlled the coating weight of steel band, and described device comprises:

The coating weight measuring apparatus is used to measure the coating weight by on the steel band of first and second air knives;

The coating weight mathematical model, relevant parameters α, the β and the γ that utilize compensation steel band speed of feed to change, the distance between each air knife and the steel band and the pressure of air knife calculate the changes in weight of coating;

The parameter correction device is used for correction parameter α, β and γ, so that make difference minimum between actual coating weight value of measuring and the calculating coating weight value of calculating in described coating weight mathematical model in described coating weight measuring apparatus;

First pressure control device is used for regulating the jetting pressure of first and second air knives when the coating weight of the hope of steel band changes, and makes the coating weight of steel band accord with the coating weight of hope; And

Second pressure control device, be used for when the speed of feed of steel band changes, regulate the jetting pressure of air knife according to the variation of steel band speed of feed, change with the compensation coating weight, it is characterized in that: when coating weight that change is wished in the continuous hot-dipping galvanizing under predetermined pressure is handled and/or speed of feed, with the output valve of first pressure control device and/or second pressure control device, regulate first and/or second air knife jetting pressure.

Described coating weight mathematical model can receive the speed of feed change amount (Δ V) of steel band according to following formula, the pressure change amount (Δ P) apart from change amount (Δ D) and air knife between steel band and the air knife:

ΔV＝ln(V _k+1)-ln(V _k)

ΔD＝ln(D _k+1)-ln(D _k)

Δ P=ln (P _K+1)-ln (P _k); Be multiplied by corresponding each the change amount of stating with corresponding parameter α, β and γ, obtain formula Δ W=α Δ V+ β Δ D+ γ Δ P; And calculate coating weight change amount then, Δ W=ln (W _K+1)-ln (W _k).

At the coating weight of the hope of steel band from T _kChange to T _K+1The time, first pressure control device can be created in following formula wishes coating weight T _K+1On the setup pressure value (P of air knife _K+1):

$\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\ln \left(T_{\mathrm{\κ}+1}\right)-\ln \left(T_{\mathrm{\κ}}\right)}{\mathrm{\γ}}$

In the speed of feed of steel band from V _kChange to V _K+1The time, second pressure control device can be created in speed of feed V with following formula _K+1On the setup pressure value (P of air knife _K+1):

$\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\mathrm{\α}[\ln \left(v_{\mathrm{\κ}+1}\right)-\ln \left(V_{\mathrm{\κ}}\right)]}{\mathrm{\γ}}$

When detecting the actual coating weight measured by the coating weight measuring apparatus and the difference between the calculating coating weight in the coating weight mathematical model, formula correction parameter alpha, β and γ below the parameter correction device is available:

θ _K+1＝θK+K _K+1[Z _K+1-h′ _K+1θ _k]

Wherein, Z _K+1=Δ W _K+1=ln (W _K+1)-ln (W _k)

According to another aspect of the invention, a kind of system that controls coating weight on the steel band in continuous hot-dipping galvanizing is handled is provided, wherein be provided with first and second air knives, by the coating weight of the airstream control steel band of winding-up predetermined pressure on the steel band that passes zinc liquid coating bath, described system comprises:

The first Coating Weight Control device, it measures steel bands and first and second air knives distance value between each in a plurality of measurement point, and change the position at the two ends of each air knife with a plurality of distance values of measuring, thus steel band is aimed at parallel with each air knife, and maintenance steel band and each air knife are equidistant;

The second Coating Weight Control device, the welding portion of two steel bands by preceding and pass through after the scheduled time in, according to the thickness difference of these two steel bands, change each position of first and second air knives, thereby proofread and correct moving of traveling route;

The 3rd Coating Weight Control device, it changes jetting pressure according to the coating weight of the hope of steel band and/or the variation of speed of feed;

The air knife distance control device, welding portion by preceding and pass through after the scheduled time, it regulates the position at first and second each two ends of air knife with the second Coating Weight Control device, after welding portion passes through, regulate each end positions of first and second air knives with the first Coating Weight Control device; With

The air knife pressure control device, it is regulated from the jetting pressure of first and second air knives winding-up with the 3rd Coating Weight Control device.Change although therefore exist in continuous hot-dipping galvanizing is handled, described system also can satisfy user's requirement.

Description of drawings

To be expressly understood above-mentioned and other purposes, feature and other advantages of the present invention more from detailed description below in conjunction with accompanying drawing, wherein:

Fig. 1 is to use the synoptic diagram of the prior art continuous hot-dipping equipment of air wiping;

The continuous coating figure of the different steel band of thickness during the continuous hot-dipping galvanizing that Fig. 2 (a) and (b) are to use air to wipe is handled;

Fig. 3 is the structural representation according to the Coating Weight Control device of the first embodiment of the present invention;

Fig. 4 is the structured flowchart of the Coating Weight Control device of first embodiment of the invention;

Fig. 5 is the Coating Weight Control device synoptic diagram of second embodiment of the invention;

Fig. 6 is the control flow chart of the Coating Weight Control device of second embodiment of the invention;

Fig. 7 is the block diagram of the coating control device of third embodiment of the invention; With

Fig. 8 is the block diagram of the Coating Weight Control system of fourth embodiment of the invention.

Embodiment

Each embodiment with reference to the accompanying drawings illustrates in greater detail composed component of the present invention and its effect.

Fig. 3 is the structural representation of the Coating Weight Control device of first embodiment of the invention.Fig. 3's and Fig. 1,2 identical composed components are with identical symbolic representation.

As shown in Figure 3, coating control device according to the present invention comprises: four distance adjustment electric motor M1, M2, M3 and M4, they are by moving first and second air knives 3 and 4 each end positions, be adjusted in the steel band 1 of X-direction and the distance between first and second air knives 3 and 4, thereby it is parallel with each nozzle to make steel band 1 aim at; Three rang sensors 21,32 and 33, they are installed in the rear side of steel band 1, measure the distance of second air knife and steel band 1; Two width sensors 34 and 35, each is positioned on the opposite end of first and second air knives 3 and 4, surveys each air knife 3 and 4 positions with respect to the width of steel band 1; With position adjustments electric motor M5, it is connected with back shaft and can moves along X-direction, described back shaft support width transmitter 34 and 35 light receiving part 34b and 35b and rang sensor 31,32 and 33.

With regard to width sensor 34 and 35, as shown in Figure 3, light emission part 34a and 35a are positioned at the two ends of first air knife 3, and light receiving part 34b is relative with light emission part 34a and 35a with 35b, are positioned at the two ends of second air knife 4.Light receiving part 34b and 35b receive from light emission part 34a and the next light of 35a.White circle represents that light receiving part 34b and 35b accept the zone of light, and the black circle is represented the light that stops because of steel band 1, and light receiving part 34b and 35b do not accept the zone of light.For simplicity, the upside of Fig. 3 is called driving side (below be called DS), and the downside of Fig. 3 is called active side (below be called WS).The front side of left side expression steel band, the right rear side of surveying the expression steel band.

Described device also comprises control section, and it is controlled the device of the relevant work of each composed component and all works, but not shown in Fig. 3.Control section preferably includes microprocessor, will describe in detail it below.

Rang sensor 31,32 and 33 is responsible for respective distance Dws, Dcs and the Dds of measurement at three points of the width of steel band 1.They are mounted on second air knife 4, therefore therewith move.At this moment, can be with laser sensor or eddy current sensor as the transmitter of measuring from second air knife to steel band 1 distance, but be not limited to specific sensor type.These three rang sensors 31,32 and 33 install Gss spaced apart a predetermined distance.Two outer distance transmitters 32 must be identical with 33 corresponding measurement.Therefore, the width of steel band is parallel to the nozzle of rear side air knife.

That is, the distance value Dds that measures in DS rang sensor 32 must be identical with the distance value of measuring in WS rang sensor 33, makes steel band 1 parallel with the nozzle of trailing flank air knife 4.For this reason, width between centers transmitter 31 need be positioned at the center of the width of steel band 1.In order to meet this requirement, need a driving mechanism, drive rang sensor 31,32 and 33 and light receiving part 34b and 35b at the width of steel band.

At this point, rang sensor 31,32 is installed on the movable axle that is connected with the 5th electric motor M5 with light receiving part 34b and 35b with 33.Width sensor 34 and 35 is surveyed the edge of steel band 1, estimates the width of steel band according to the result who surveys.At last, regulating the 5th electric motor M5 makes rang sensor 31 be positioned at the center of the width of steel band 1.That is, width sensor 34 and 35 has the situation of the photometry region of similar number outside two, then is positioned at the center of the rang sensor 31 at center at the width of steel band 1.

As shown in Figure 3, on two ends that width sensor 34 and 35 light emission part 34a and 35a are installed in first air knife 3.Their light receiving part 34b and 35b are installed on the two ends of back shaft 36, and the back shaft 36 and second air knife 4 are positioned on the straight line, make light receiving part 34b relative with light emission part 34a and 35a with 35b.Photorectifier light is arranged on the straight line of width of inboard steel band of light receiving part 34b and 35.Therefore, if light receiving part is accepted the light of light emission part 34aa.Then export the predetermined current amount.In the situation of the width of the mensuration steel band of steel milling train, be extensive use of such width measurements mode.Aforesaid way is applied to the present invention, makes rang sensor 31-33 be positioned at the center of the width of steel band.

Fig. 4 is the skeleton diagram of control section structure of the Coating Weight Control device of control chart 3.Fig. 4 (a) uses the width information that obtain from width sensor 34 and 35 to control the treating processes figure of the 5th electric motor M5, and the 5th electric motor M5 is for rang sensor 31,32 and the 33 transfer electric motor in the width positioned centrally of steel band.Fig. 4 (b) is, with rang sensor 31,32 and 33 observed values that obtain, and distance adjustment electric motor M1, the M2 of four points of regulating and controlling position, the treating processes figure of M3 and M4, four points are the points at two each two ends of air knife.

As shown in Figure 4, the control section according to control Coating Weight Control device of the present invention comprises: first logical block 41, position controller for motor 42, the second logical blocks 43 and position controller for motor 44-47.From first and second width sensors 34 and 35 to photometry number of diodes Nws and the Ndss of first logical block 41 input among light receiving part 34b and 35b.Then, first logical block 41 is calculated, with the movement value Δ Gc of the electric motor of the balanced number of the light receiving diode in corresponding light receiving part 34b and 35.Position controller for motor 42 moves the electric motor movement value that the 5th electric motor calculates as far as first logical block 41.Be transformed into the distance that three rang sensor 31-33 of X-Y coordinate figure measure from second air knife to steel band (X0, Y0), (X1, Y1) and (X2 Y2) is imported into second logical block 43.Second logical block 43 is calculated the value Δ Y1 that each electric motor moves, Δ Y2, Δ Y3 and Δ Y4, so as location steel band 1 and first and second air knives 3 with 4 each is parallel, and maintenance and each air knife are equidistant.The movement value of each electric motor that second logical block 43 is calculated is imported into the position controller for motor 44-47 that electric motor M1-M4 is moved to each desired location.

Position controller for motor changes according to the type of controlled electric motor, the present invention be not restricted to specific electric motor or the electrode position control device.

First logical block 41 is according to the miles of relative movement (Δ Gc) of following formula computed range transmitter:

Formula 1

ΔGc＝(Nws-Nds)×Pss

Wherein, Δ Gc is the movement value at the width rang sensor of steel band, Nws is the number of the photometry diode of WS width sensor 35, Nds is the number of the photometry diode of DS width sensor 34, and Pss be install on the light receiving part 34b of width sensor 34 and 35 and the 35b photorectifier between distance.

Position controller for motor 42 drives the 5th electric motor M5 according to the movement value with formula 1 calculated distance transmitter 31-33.Therefore, if at X-direction miles of relative movement transmitter 31-33, so Nws equals Nds, and then the 5th electric motor M5 is no longer mobile.At this state, rang sensor 31-33 is positioned at the center of the width of steel band 1.

Second logical block 43 is carried out work according to following program, and calculates 4 points, that is, and and the corresponding movement value of the end points of air knife.

Calculate the average movement value of first and second air knives 3 and 4, so that maintenance steel band and each air knife are equidistant.

For this reason, be the quadratic equation of formula 2 with the curve representation of steel band, at this moment, coordinate system as shown in Figure 3:

Formula 2

S(x)：y＝ax ²+bx+c

(x0, y0) (x1 is y1) with (x2 y2) satisfies formula 2 to three pairs of coordinates of three rang sensor 31-33 measurements.

Therefore, three pairs of coordinates that three rang sensor 31-33 measure are by substitution formula 2, thereby form three simultaneous equations.If separate this three simultaneous equation, then can obtain coefficient a, b and the c of formula 2.

Describe the effect of second logical block 43 below in detail.

See Fig. 3, the y axle is perpendicular to the transverse axis of air knife 3 and 4, and the x axle is perpendicular to the y axle, thus the x-y coordinate plane of formation two dimension.Can select anyly as initial point, the curve representation of steel band is the quadratic equation S (x) of formula 2.

It is right that the distance from second air knife to steel band that three rang sensor 31-33 survey is changed into the x-y coordinate, thus express respectively (x0, y0), (x1, y1) and (x2, y2).These three coordinates to (x0, y0), (x1, y1) and (x2 during y2) by the quadratic equation of substitution formula 2, then can solve coefficient a, b and c.Therefore, obtain to describe the specific function of steel band.

Be updated to the average movement value that following formula 3 calculates first air knife 3 and second air knife 4 by describing the above-mentioned quadratic power of steel band:

Formula 3

$\mathrm{\ΔY}=\frac{[{\∫}^W(S\left(x\right)-L_T\left(x\right))\mathrm{dx}-{\∫}^W(L_B\left(x\right)-S\left(x\right))\mathrm{dx}]}{2W}$

Wherein, Δ Y is the average movement value of first air knife 3 and second air knife 4, W is the width of steel band of measuring in width sensor 34 and 35, and LT (x) is a linear equation of describing the nozzle of first air knife 3, and LB (x) is a linear equation of describing the nozzle of second air knife 4.

Describe the linear equation of the respective nozzle of first and second air knives 3 and 4 and represent, the position of first and second air knives 3 in above-mentioned x-y coordinate system and 4 nozzle separately.That is, the position of the nozzle separately of first and second air knives can be expressed as the linear equation in the x-y coordinate shown in Figure 3.Preferably, with this linear equation of formal representation of y=a ' x+b '.

Then, calculate the movement value at first and second air knives 3 and 4 each two ends, thereby the nozzle separately of locating first and second air knives 3 and 4 is parallel to steel band 1.

For this reason, calculate at first and second air knives 3 of DS and WS and 4 movement value separately with following formula 4 and 5.Formula 4 produces the DS movement value, and formula 5 produces the WS movement value.

Formula 4

$\mathrm{\ΔYds}=\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{M}{G_{\mathrm{ss}}}$

Formula 5

$\mathrm{\ΔYws}=-\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{(L-M)}{G_{\mathrm{ss}}}$

Wherein, Δ Yds is the DS movement value of first and second air knives 3 and 4, Δ Yws is the WS movement value of first and second air knives 3 and 4, M is the width sensor 31 of central position and the x direction of principal axis slant range between the 4th electric motor M4, and L is the distance between WS distance adjustment electric motor M3 and the DS distance adjustment electric motor M4 in second air knife 4.

At last, steel band 1 is kept and first and second air knives 3 and 4 each equidistant average movement value Δ Y, Δ Yws of movement value separately and the Δ Yds substitution formula 6 of the WS/DS that remains parallel to each other with respective nozzle with first and second air knives 3 and 4, thereby obtain distance adjustment electric motor M1, M2, the movement value separately of M3 and M4.

Formula 6

ΔY1＝-ΔY-ΔYws

ΔY2＝-ΔY-ΔYds

ΔY3＝ΔY+ΔYws

ΔY4＝ΔY+ΔYds

Wherein, Δ Y1 is the final movement value of the WS distance adjustment electric motor M1 of first air knife 3, Δ Y2 is the final movement value of the DS distance adjustment electric motor M2 of first air knife 3, Δ Y3 is the final movement value of WS distance adjustment electric motor M3 of second air knife 4 and the final movement value of the DS distance adjustment electric motor M4 that Δ Y4 is second air knife 4.

If calculated distance adjustment electric motor M1, M2, the movement value separately of M3 and M4 is just then the position control 44-47 of corresponding each electric motor regulates the position of each air knife.Its result, steel band always keeps with first and second air knives 3 and 4 each is equidistant, and each nozzle is in the position parallel to each other in the width of steel band 1.

Coating Weight Control device according to first embodiment of the invention, corresponding mean distance between each air knife and steel band is total to keep equal, the respective nozzle of each air knife is positioned in the width of steel band 1 parallel to each other, and causing the width coating weight of steel band and the front and back side coating weight of steel band almost is uniform distribution.Therefore, can prevent the loss of coating deficiency and undue product defects and zinc, save and produce cost.

Fig. 5 is the Coating Weight Control schematic representation of apparatus of second embodiment of the invention.Notice such fact, that is, depend on the movement value of traveling route of the variation in thickness of steel band, proportional with the thickness and the variation in thickness of steel band, so the mobile of traveling route estimated.Behind each air knife and the actual range between the steel band of measuring at welding portion, proofread and correct the value of prediction and the error between the actual value.Describe the composed component and the effect of described device in detail below with reference to Fig. 5.

The Coating Weight Control device of Fig. 5 comprises: distance measuring unit 7; Welding portion determination unit 51; Miles of relative movement is measured logical block 52; Miles of relative movement prediction logic unit 53; Parameter logical block 54; Switch unit 55; Switch control unit 56; Motor position control unit 57 and 58; With removable motor unit 59 and 60.Distance measuring unit 7 is responsible for measuring the distance between second air knife 4 and steel band 1.Welding portion determination unit 51 is installed in the upstream of first and second air knives in the steel band feed line, and surveys the different steel band 1a of two thickness and the welding portion P of 1b weld.Distance value between steel band 1a that distance measuring unit 7 is measured and 1b each and second air knife 4 is placed in the miles of relative movement measuring unit 52, it is measured according to the steel band 1 of the distance between the steel band 1 and second air knife 4 then, the movement value of the traveling route of steel band 1, and calculate the miles of relative movement separately of first and second air knives 3 and 4.Miles of relative movement prediction logic unit 53 calculates, with Prediction Parameters, before welding portion P and after the steel band 1a of front and the variation in thickness between the steel band 1b of back, calculate the traveling route movement value of steel band 1, and produce the movement value separately of first and second air knives 3 and 4.Parameter logical block 54 correct operation parameters are to proofread and correct the error between traveling route movement value of predicting and the traveling route movement value of measuring in miles of relative movement measurement logical block 22 in miles of relative movement prediction logic unit 53.Switch unit 55 is selectively exported, and miles of relative movement prediction logic unit 53 and miles of relative movement are measured first and second air knives 3 of logical block 52 each output and 4 corresponding miles of relative movement.Switch control unit 56 is according to the change location of the welding portion of welding portion determination unit 51 detections, control switch unit 55, the scheduled time after welding portion passes through to stablize roller 6, select the output valve of miles of relative movement prediction logic unit 53, and except the above-mentioned scheduled time, selecting miles of relative movement to measure the output valve of logical block 52.Motor position control unit 57 and 58 is responsible for the removable electric motor of control first and second air knives 3 and 4, so that move first and second air knives 3 and 4 according to the movement value of switch unit 55 outputs.Each removable motor unit 59 and 60 is made of one or more electric motor, and they move corresponding first and second air knives 3 and 4 with the back forward, and are driven under the control of corresponding motor position control unit 57 and 58.

Though only express motor unit 59 and 60 in Fig. 5, motor unit 59 and 60 is made of four electric motor M1-M4, and they move first and second air knives 3 shown in Figure 3 and two ends of 4.Can be according to conventional methods or the method for above-mentioned first embodiment, measure in logical block 52 and the miles of relative movement prediction logic unit 53 in miles of relative movement and to produce, depend on what steel band moved, first and second air knives 3 and 4 each the movement value at two ends.

Fig. 6 is the control flow chart of the Coating Weight Control device of second embodiment of the invention.Principle below with reference to the Coating Weight Control device shown in Fig. 6 explanatory view 5.

According to second embodiment of the invention, two steel band 1a and soldered hot dip processs continuously then of 1b that thickness is different.

At this moment, notice when the different steel band of thickness passes through the space of qualification between first and second air knives 3 and 4, the movement value of the traveling route of steel band and the thickness and the variation in thickness of steel band are proportional, so design Coating Weight Control device, and work in the following manner according to second embodiment.

When welding portion determination unit 51 is surveyed entering of welding portion P (S601), miles of relative movement prediction logic unit 53 calculates, in the border of welding portion P, the thickness (T of front steel band 1a ₁) and the thickness (T of back steel band ₂) variation (Δ T=T ₂-T ₁) (S602).

Based on the variation in thickness of aforementioned calculation, calculate the movement value of the prediction of traveling route according to following formula 7 The prediction movement value of definite movement value (Δ P) of the air knife of 22 outputs and traveling route from miles of relative movement prediction logic unit

Identical (S603).

Formula 7

$\hat{S}={\mathrm{\αT}}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}+\mathrm{\β\ΔT}$

Wherein, α and β are miles of relative movement prediction work parameters.

At the prediction movement value of welding portion P by generation traveling route before stablize roller 6, whether inspection has passed through the scheduled time from the detection time of welding portion P then.If passed through this scheduled time (S604), promptly welding portion leaves welding portion determination unit 51 according to the working direction of steel band and advances, by stablize roller 6 therefore the traveling route move, then according to the prediction movement value of traveling route

Regulate the position (S605) of first and second air knives 3 and 4.For this reason, behind first setting-up time of the detectable signal output beginning of welding part determination unit 51 certainly, the switching effect of switch control unit 56 control switch units 55 to motor position control unit 57 and 58, applies the output valve of miles of relative movement prediction logic unit 53.Motor position control unit 57 and 58 prediction movement values according to the traveling route that in moving projection logical block 53, calculates

Move the removable motor unit 59 and 60 separately of first and second air knives 3 and 4.

To be welding portion P advance the required time to stablizing roller 6 from the detecting location of welding portion determination unit 51 described first setting-up time.

By behind first and second air knives 3 and 4, measure the actual range between the steel band 1b and second air knife in the back at the part P of welding, and accurately impartial at welding portion by any difference between the observed value of front and back.In detail, by first and second air knives 3 and 4 front and back, measure, at the air knife of reference, promptly at second air knife 4 and the respective distance D1 between the steel band and the D2 (S606-S608) of the rear side of steel band with distance measuring unit 51 at welding portion P.

Miles of relative movement is measured the logical block 52 usefulness steel band 1a in front and the distance value D1 of the measurement between second air knife 4, at the steel band 1b of back and the distance value D2 of the measurement between second air knife 4, at the position P1 of welding portion P by second air knife 4 before first and second air knives 3 and 4, after passing through first and second air knives 3 and 4 at welding portion P, position P2 according to second air knife 4 that moves of miles of relative movement prediction logic unit 53 prediction, according to formula 8, calculate the movement value S of the reality of traveling route.At this moment, by from the actual movement value (S) of traveling route, deducting the prediction movement value of traveling route

Obtain, and the output valve of determining (Δ P) of miles of relative movement measuring unit 52 (S609, S610).

Formula 8

S＝(D ₂-D ₁)-(P ₂-P ₁)

Therefore, by from actual movement value (S), deducting the prediction movement value

The value that obtains moves first and second air knives 3 and 4 correction errors (S611).

In detail, in welding part determination unit 51 certainly, detect welding portion through second setting-up time after, switch control unit 56 control switch units 55 apply the output valve that miles of relative movement is measured logical block 52 to motor position control unit 57 and 58.Then, according to actual movement value with from the difference between the prediction movement value of miles of relative movement measurement logical block 52 outputs

Regulate the position of first and second air knives 3 and 4.

Prediction movement value in miles of relative movement prediction logic unit 53 When identical with the actual movement value of traveling route (S) of miles of relative movement measuring unit 52, the output valve that applies to motor position control unit 57 and 58 is zero (0).

This expression has realized accurate movement value prediction in miles of relative movement prediction logic unit 53.On the contrary, at the prediction movement value of miles of relative movement prediction logic unit 53 When inequality, then the parameter of using in the work of miles of relative movement prediction logic unit 53 (α in the formula 7 and β) is incorrect with the actual movement value of traveling route (S) of miles of relative movement measuring unit 52_, and therefore inaccurate forecast takes place.Therefore, must Reparametrization α and β.About this point, at step S612, at the movement value of prediction And the difference between the actual movement value (S) is when being zero, the finishing control step, but otherwise, according to formula 9 correction parameter α and β:

Formula 9

$\mathrm{\α}(t+1)=\mathrm{\α}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\α}}\frac{\∂(S-\hat{S})}{\∂\mathrm{\α}}=\mathrm{\α}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\α}}{T}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}$

$\mathrm{\β}(t+1)=\mathrm{\β}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\β}}\frac{\∂(S-\hat{S})}{\mathrm{\α\β}}=\mathrm{\β}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\β}}\mathrm{\ΔT}$

Here, γ _α, γ _βIt is the coefficient known of α and β.

In parameter logical block 54, carry out the parameter alpha of miles of relative movement prediction work and the correction of β (S612 and S613).

As mentioned above, according to second embodiment of the invention, two steel bands that continuous hot-dipping thickness is different.Before the space that welding portion limits by two air knives, with the thickness of steel band and the traveling route of variation in thickness adjusting steel band.Therefore, can overcome operator's conventional control arbitrarily inaccurate.In the time of behind the space that welding portion limits by two air knives, rang sensor is measured the actual miles of relative movement of the traveling route of steel band, therefore is controlled at the distance between two air knives and the steel band exactly.Therefore, can minimize, frequently produce the variation of the coating weight between the front and back side of steel band in the steel band that in the prior art continuous hot-dipping, extends from welding portion to hundreds of rice.Its result makes that not enough coating is reduced to minimum degree with undue coating in continuous hot-dipping galvanizing is handled, and therefore, prevents the loss of product defects and zinc, saves cost.

Though control the distance between two air knives and the steel band exactly, when the plating check weighing quantitative change of hope, still inaccurate coating can take place.In order to overcome this problem, the present invention changes according to the coating weight of hope, the control jetting pressure.

Fig. 7 is the Coating Weight Control device skeleton diagram that the present invention the 3rd has implemented.Described layer weight control device comprises: coating weight measuring unit 71; Coating Weight Control unit 72; With pressure control device 73.Coating weight measuring unit 71 is responsible for measuring the coating weight that has passed through first and second air knives 3 and the 4 spatial steel bands that limit.The actual coating weight that Coating Weight Control unit 72 will be measured in coating weight measuring unit 71 and the coating weight of hope are relatively regulated the jetting pressure set(ting)value then to reach the coating weight of hope.Pressure control device 73 pilot air valves 8 are so that jet under the pressure of the setting of airstream in Coating Weight Control unit 72.Coating Weight Control unit 72 comprises: parameter estimation device 721; Coating weight mathematical model 723, it receives the coating weight value of measuring, and the force value of feedback control setting, to reach the coating weight of hope; Preset control device 724, its output setup pressure value of the time when the coating weight of hope changes; Feedforward control device 725.Describe their each function and structure below in detail.

According to coating weight mathematical model 723, with three parameter alpha, β and γ, the distance D between steel band and the air knife, the feed line speed V of the air pressure P of air knife and steel band is expressed as following formula 10 with coating weight W.At current time k, corresponding each argument table is shown V _k, D _kAnd P _kAt this moment, coating weight is W _kAt next time k+1, each argument table is shown V _K+1, D _K+1And P _K+1Obtain coating weight with following formula 10 at time k+1:

Formula 10

If Δ V=ln is (V _K+1)-ln (V _k)

ΔD＝ln(D _k+1)-ln(D _k)

ΔP＝ln(P _k+1)-ln(P _k)；

ΔW＝ln(W _k+1)-ln(W _k)，

Δ W=α V+ β D+ γ P then.

Constantly measure above-mentioned variable V, D and P.

Time when the coating weight variation that steel band is wished is with presetting control device 724.At the coating weight of the hope of steel band from T _kTo T _K+1During change, with the setup pressure value (P of following formula 11 acquisitions at the temporal air knife of k+1 _K+1):

Formula 11

$\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\ln \left(T_{\mathrm{\κ}+1}\right)-\ln \left(T_{\mathrm{\κ}}\right)}{\mathrm{\γ}}$

Time when the speed of feed of steel band changes is used feedforward control device 725.In the speed of feed of steel band from V _kChange to V _K+1The time, with the setup pressure value (P of following formula 12 acquisitions in the k+1 time _K+1):

Formula 12

$\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\mathrm{\α}[\ln \left(v_{\mathrm{\κ}+1}\right)-\ln \left(V_{\mathrm{\κ}}\right)]}{\mathrm{\γ}}$

The effect of parameter estimation device 721 is parameter alpha of optimizing formula 10, β and γ.In parameter alpha, when β and γ are incorrect, occur in the error between coating weight that calculates in the formula 10 and the actual coating weight of in coating weight measuring unit 71, measuring.With the parameter estimation device 230 of this error minimize optimisation technique, estimate the parameter of coating weight mathematical model based on the recurrent least square method that is referred to as the scientific terminology in linear algebra.

In parameter estimation device 230, use following equation 13 according to recurrent least square method.

In detail, at current time k, be V in variables corresponding _k, D _kAnd P _kThe time, the actual coating weight of measuring in coating weight measuring unit 71 is expressed as W _kIn the next time of k+1, be V in variables corresponding _K+1, D _K+1And P _K+1The time, the actual coating weight of measuring in coating weight measuring unit 71 is expressed as W _K+1With the parameter alpha that following formula 13 obtained in the time of k+1, β and γ:

Formula 13

If Z _K+1=Δ W _K+1=ln (W _K+1)-ln (W _k),

θ then _K+1=θ _K+ K _K+1[Z _K+1-h ' _K+1θ _k]

In a word, coating weight mathematical model 723 relies on the actual coating weight of measuring in the coating weight measuring unit 71, exports the setup pressure value of the coating weight of the hope that reaches relevant.When changing the coating weight of wishing, preset control device 724 usefulness formula 11 output setup pressure value.When on-line velocity changed, then feedforward control device 725 usefulness formula 12 were exported setup pressure value according to the variation of linear velocity.

Setup pressure value according to corresponding conditions output is added to pressure control device 73.Pressure control device 73 is regulated the degree that opens and closes pressure lock 8 according to the output valve of Coating Weight Control unit 72, makes jetting pressure be conditioned.

As mentioned above, according to third embodiment of the invention, when the coating weight of hope or change of line speed, can control the pressure of air knife exactly.As a result, the difference between the coating weight of hope and actual coating weight can be minimized.And, farthest prevented to save production cost because coating is not enough and the excessive product of inferior quality that causes.Because parameter estimation device of the present invention is considered the various variations that take place when air knife equipment and other equipment routine preventive maintenance relevant with coating weight, make described mathematical model adaptation new state condition, so reduced the burden of overhaul of the equipments.

Can be separately or be used in combination each the Coating Weight Control device of the first, the second and the 3rd embodiment according to the present invention.But, one when being used from continuous hot-dipping equipment, can realize the more accurate control of coating weight at them.

Fig. 8 is the skeleton diagram of the Coating Weight Control system during continuous hot-dipping galvanizing is handled, and combines the one the second and the related device of the 3rd embodiment in described system.Described system comprises: the first Coating Weight Control device 81; The second Coating Weight Control device 82; Shifter 83; Air knife distance control device 84; The 3rd Coating Weight Control device 85; With air knife pressure control device 86.The first Coating Weight Control device 81, the distance of measurement from a plurality of o'clock on the steel band to second air knife, and from the distance of a plurality of points of measuring changes each the position at two ends of first and second air knives, thereby steel band location is parallel with each air knife, and maintenance steel band and each air knife are equidistant.The second Coating Weight Control device 82 in the scheduled time of welding portion by front and back, according to the thickness difference between two steel bands, changes the position of first and second air knives, compensates moving of traveling route.Shifter 83, welding portion by preceding with after the scheduled time air knife distance control device 84 is connected with the second Coating Weight Control device 82, and after welding portion passes through, air knife distance control device 84 is connected with the first Coating Weight Control device 83.Air knife distance control device 84 according to the control of the first and second Coating Weight Control devices 81 and 82, is regulated each the position at two ends of first and second air knives.The 3rd Coating Weight Control device 85, the coating weight and/or the change of line speed of the hope of dependence steel band are regulated jetting pressure.Air knife pressure control device 86, according to the control of the 3rd Coating Weight Control device 85, the jetting pressure that control adds on first and second air knives.

The first Coating Weight Control device 81 is according to the first embodiment of the invention shown in Fig. 3 and 4, the second Coating Weight Control device 82 is to be according to the third embodiment of the invention shown in Fig. 7 according to second embodiment of the invention shown in Fig. 5 and the 3rd Coating Weight Control device.

Weld in the continuous hot-dipping galvanizing processing of continuous coating at two or more steel bands, the Coating Weight Control system according to the coating weight and the change of line speed of hope, controls the jetting pressure of first and second air knives with the 3rd Coating Weight Control device 83.

In the scheduled time of passing before and after the coating bath, in conjunction with the welding portion of two different steel bands of thickness under the control of the second Coating Weight Control device 82.Therefore, according to depending on moving of traveling route that thickness of strips changes, be controlled at the distance between first and second air knives each and the steel band.Rest part (in the zone between the welding portion) in the mode of feedback under the control of the first Coating Weight Control device 81, thereby cause each and steel band of first and second air knives parallel to each other, it is equidistant with each air knife that steel band keeps.

Therefore, described system can control continuous hot-dipping galvanizing equipment, although so that change in the continuous hot-dipping galvanizing processing, can plate the coating weight of hope.

Though the invention discloses the preferred embodiments of the present invention in order to illustrate, the insider understands, and under the scope of the invention that does not depart from claim and spirit, various variation schemes can be arranged.

Claims (18)

1. One kind control continuous hot-dipping galvanizing handle in the device of coating weight on the steel band, wherein be provided with first and second air knives, be used for controlling coating weight on the steel band by the airstream of winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath, described device comprises:

   Multiple spurs is from measuring apparatus, and the center that is installed in back shaft is spaced apart a predetermined distance, the described back shaft and second air knife in a straight line, described multiple spurs is measured distance between steel band and the described air knife from measuring apparatus;

   Distance adjusting means when moving forward and backward each two ends of first and second air knives, is regulated the distance between first and second air knives each and the steel band;

   Width of measuring device, the width of measurement steel band; With

   The apparatus for adjusting position of described distance-measuring device according to the measurement result of described width of measuring device, makes distance-measuring device can be positioned at the center of the width of steel band.
2. 2. according to the device of claim 1, it is characterized in that: described width of measuring device is made of first and second width sensors, they each be included in light emission part and the light receiving part on back shaft on first air knife, described back shaft be installed on the relative end of first and second air knives and with second air knife on a straight line, partly launch the light time at light emission, the light that width sensor is surveyed by light receiving part is determined the position and the width of steel band.
3. 3. according to the device of claim 2, it is characterized in that: described apparatus for adjusting position is by constituting with lower device:

   The position adjustments electric motor, it moves described back shaft along the width of steel band, and wherein the light receiving part of first and second width sensors and multiple spurs are installed on the described back shaft from measuring apparatus;

   Drive the position controller for motor of described position adjustments electric motor; With

   First logical block, it calculates the movement value of described position adjustments electric motor, and the value that will calculate places position controller for motor then, so that the light quantity of surveying at the corresponding light receiving unit of first and second width sensors equates.
4. 4. according to the device of claim 2, it is characterized in that: the corresponding light receiving part of first and second width sensors comprises a plurality of photorectifiers, and they are arranged in along the width of steel band spaced apart a predetermined distance.
5. 5. according to the device of claim 4, it is characterized in that: the movement value of the following computed range measuring apparatus of first logical block:

   ΔGc＝(Nws--Nds)×Pss

   Wherein, Δ Gc is the movement value of distance-measuring device, and Nws is the number of photometry photorectifier in first width sensor, and Nds is the number of photometry photorectifier in the two or two width sensor, and Pss is the distance between the photorectifier.
6. 6. according to the device of claim 1, it is characterized in that: distance-measuring device is made of three or more rang sensor spaced apart a predetermined distance.
7. 7. according to the device of claim 6, it is characterized in that: distance adjusting means is by constituting with the lower section:

   Four or a plurality of distance adjustment electric motor, when described electric motor was connected to each two ends of first and second air knives, described electric motor moved forward and backward along the steel band direction;

   Second logical block, utilization is calculated the movement value at first and second each two ends of air knife by the steel band of rang sensor measurement and the distance between second air knife, thereby steel band maintenance and each air knife is equidistant parallel with each air knife with the maintenance steel band; With

   Four or a plurality of position controller for motor, they are according to from each the movement value at two ends of first and second air knives of second logical block output, and miles of relative movement is regulated electric motor.
8. 8. according to the device of claim 7, it is characterized in that: second logical block: a) with any as initial point, limit the X-Y coordinate plane that the Y-axis of the X-axis of the front/rear travel direction of first and second air knives and width of steel band direction is crossed over; B) will be following formula at the curve representation of the steel band on the described X-Y coordinate plane:

   S(x)：y＝ax ²+bx+c

   (wherein, S (x) is the curvilinear function of the steel band on the X-Y coordinate plane, and a, b and c are the coefficients of S (x)); C) change multiple spurs into the X-Y coordinate figure from a plurality of observed values that measuring apparatus obtains; D), obtain coefficient a, b and c with in the X-Y coordinate figure substitution function S (x); E) with the formula below S (x) substitution that obtains:

   $\mathrm{\ΔY}=\frac{[{\∫}^W(S\left(x\right)-L_T\left(x\right))\mathrm{dx}-{\∫}^W(L_B\left(x\right)-S\left(x\right))\mathrm{dx}]}{2W}$

   (wherein, Δ Y represents the average movement value of first and second air knives, and W represents the width size of the steel band that width sensor is surveyed, L _T(x) linear equation of the expression first air knife nozzle, and L _B(x) linear equation of the expression second air knife nozzle), thus obtain the average movement value Δ Y of first and second air knives; F) calculate the movement value Δ Yds and the Δ Yws of two ends of first and second air knives with following formula:

   $\mathrm{\ΔYds}=\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{M}{G_{\mathrm{ss}}},$ $\mathrm{\ΔYws}=-\frac{(D_{\mathrm{WS}}-D_{\mathrm{ds}})}{2}\frac{(L-M)}{G_{\mathrm{ss}}}$

   (wherein Δ Yds is the movement value of an end of first and second air knives, Δ Yws is the movement value of the other end of first and second air knives, M be multiple spurs from the distance-measuring device at measuring apparatus center and with distance adjusting means that an end of second air knife is connected between slant range, and L is the distance between two distance-measuring devices on the two ends of second air knife); And g) calculate each the final movement value Δ Y1 at two ends of first and second air knives with following formula then, Δ Y2, Δ Y3 and Δ Y4:

   ΔY1＝-ΔY-ΔYws

   ΔY2＝-ΔY-ΔYds

   ΔY3＝ΔY+ΔYws

   ΔY4＝ΔY+ΔYds

   (wherein, Δ Y1 is the final movement value of an end (WS) of first air knife, Δ Y2 is the final movement value of the other end (DS) of first air knife, and the final movement value of an end (WS) of Δ Y3 second air knife, Δ Y4 are the final movement values of the other end (DS) of second air knife).
9. 9. the device of the coating weight on the control steel band in continuous hot-dipping galvanizing is handled, wherein be provided with first and second air knives, airstream by winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath is controlled coating weight on the steel band, and described device comprises:

   Apparatus for adjusting position is used to regulate the position of first and second air knives;

   The welding portion determinator is used for surveying the change location of the welding portion that two different steel bands of zinc liquid plating mortise thickness are combined;

   Distance-measuring device is used to measure the distance between second air knife and the steel band;

   Miles of relative movement prediction logic device, according to the thickness information of steel band, the movement value of the variation in thickness of the steel band of steel band by calculating the front and the welding back on it and the traveling route of steel band calculates each miles of relative movement of first and second air knives;

   Miles of relative movement is measured logical unit, utilizes steel band that distance-measuring device measures and the distance between second air knife, calculate welding portion by preceding and pass through after the traveling route movement value of steel band, calculate each miles of relative movement of first and second air knives;

   The parameter correction device, the parameter that is used to proofread and correct miles of relative movement prediction logic device is so that the miles of relative movement predicted in miles of relative movement prediction logic device of compensation and measure error between the miles of relative movement of measuring in the logical unit in miles of relative movement;

   Shifter, it is selected between the miles of relative movement of first and second air knives output of miles of relative movement prediction logic device and the output of miles of relative movement measurement logical unit, then selected miles of relative movement value is applied to apparatus for adjusting position; With

   Switch control unit, the change location of the welding portion of surveying according to the welding portion determinator, except before welding portion is by first and second air knives and after the scheduled time in apply the output valve of miles of relative movement prediction logic device to apparatus for adjusting position, apply the output valve that miles of relative movement is measured logical unit to apparatus for adjusting position.
10. 10. according to the device of claim 9, it is characterized in that: miles of relative movement prediction logic device to following formula input front/back steel band each thickness and the thickness difference between them:

    $\hat{S}=\mathrm{\α}{T}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}+\mathrm{\β\ΔT}$

    (wherein,

    

    Be the prediction movement value of traveling route, T ₁Be the thickness of front steel band, Δ T is the thickness difference between steel band and the back steel band in front, α and β are the predictor variablees), thus the prediction movement value of steel band traveling route calculated, produce each prediction miles of relative movement of first and second air knives according to the movement value of traveling route then.
11. 11. device according to claim 9, it is characterized in that: described miles of relative movement measure logical unit from described distance-measuring device receive front/back steel band each with second air knife between the distance value of measurement, then with the actual movement value of the traveling route of following formula calculating steel band:

    S＝(D ₂-D ₁)-(P ₂-P ₁)

    Wherein, S is the actual movement value of traveling route, D ₁Be the distance between steel band and second air knife in front, D ₂Be by the distance between the back steel band and second air knife, P at welding portion ₁Be the position that welding portion passes through preceding second air knife, and P ₂It is the position of second air knife after welding portion passes through.
12. 12. the device according to claim 9 is characterized in that: described parameter correction device is according to the operating parameters of the described miles of relative movement prediction logic of following formula correction device;

    $\mathrm{\α}(t+1)=\mathrm{\α}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\α}}\frac{\∂(S-\hat{S})}{\∂\mathrm{\α}}=\mathrm{\α}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\α}}{T}_1\frac{\mathrm{\ΔT}}{\left|\mathrm{\ΔT}\right|}$

    $\mathrm{\β}(t+1)=\mathrm{\β}\left(t\right)+{\mathrm{\γ}}_{\mathrm{\β}}\frac{\∂(S-\hat{S})}{\∂\mathrm{\β}}=\mathrm{\β}\left(t\right)-{\mathrm{\γ}}_{\mathrm{\β}}\mathrm{\ΔT}$

    γ wherein _α, γ _βIt is the coefficient of knowing of α and β.
13. 13. the device of the coating weight on the control steel band in continuous hot-dipping galvanizing is handled, wherein be provided with first and second air knives, airstream by winding-up predetermined pressure on two surfaces of the steel band that passes zinc liquid coating bath is controlled the coating weight of steel band, and described device comprises:

    The coating weight measuring apparatus is used to measure the coating weight by on the steel band of first and second air knives;

    The coating weight mathematical model, the changes in weight of relevant parameters α, the β that utilization compensation steel band speed of feed changes and the calculation of pressure coating of distance between γ, each air knife and the steel band and air knife;

    The parameter correction device, correction parameter α, β and γ are so that make difference minimum between actual coating weight value of measuring in the described coating weight measuring apparatus and the calculating coating weight value of calculating in described coating weight mathematical model;

    First pressure control device is used for regulating the jetting pressure of first and second air knives when the coating weight of the hope of steel band changes, and makes the coating weight of steel band accord with the coating weight of hope;

    Second pressure control device, be used for when the speed of feed of steel band changes, regulate the jetting pressure of air knife according to the variation of steel band speed of feed, change with the compensation coating weight, wherein when coating weight that changes hope in the processing of continuous hot-dipping galvanizing under predetermined pressure and/or speed of feed, with the output valve of first pressure control device and/or second pressure control device, regulate the jetting pressure of first and/or second air knife.
14. 14. device according to claim 13, it is characterized in that: described coating weight mathematical model, according to following formula, the pressure change amount (Δ P) between speed of feed change amount (Δ V), steel band and the air knife of reception steel band apart from change amount (Δ D) and air knife:

    ΔV＝ln(V _k+1)-ln(V _k)

    ΔD＝ln(D _k+1)-ln(D _k)

    Δ P=ln (P _K+1)-ln (P _k); Be multiplied by corresponding each the change amount of stating with corresponding parameter α, β and γ, obtain formula Δ W=α Δ V+ β Δ D+ γ Δ P; And calculate coating weight change amount then, Δ W=ln (W _K+1)-ln (W _k).
15. 15. the device according to claim 13 is characterized in that: at the coating weight of the hope of steel band from T _kChange to T _K+1The time, first pressure control device is created in following formula wishes coating weight T _K+1On the setup pressure value (P of air knife _K+1):

    $\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\ln \left(T_{\mathrm{\κ}+1}\right)-\ln \left(T_{\mathrm{\κ}}\right)}{\mathrm{\γ}}$
16. 16. the device according to claim 13 is characterized in that: in the speed of feed of steel band from V _kChange to V _K+1The time, second pressure control device is created in speed of feed V with following formula _K+1On the setup pressure value (P of setting of air knife _K+1):

    $\ln \left(P_{\mathrm{\κ}+1}\right)=\ln \left(P_{\mathrm{\κ}}\right)+\frac{\mathrm{\α}[\ln \left(v_{\mathrm{\κ}+1}\right)-\ln \left(V_{\mathrm{\κ}}\right)]}{\mathrm{\γ}}$
17. 17. device according to claim 13, it is characterized in that: during difference between actual coating weight of measuring in detecting the coating weight measuring apparatus and the coating weight that calculates in the coating weight mathematical model, the parameter correction device is with following formula correction parameter alpha, β and γ:

    θ _K+1＝θ _K+K _K+1[Z _K+1-h′ _K+1θ _k]

    Wherein, Z _K+1=Δ W _K+1=ln (W _K+1)-ln (W _k)

    $h_{k+1}=\left[\begin{array}{c}\mathrm{\Δ}{V}_{k+1}\\ \mathrm{\Δ}{D}_{k+1}\\ \mathrm{\Δ}{P}_{k+1}\end{array}\right]=\left[\begin{array}{c}\ln \left(V_{k+1}\right)-\ln \left(V_k\right)\\ \ln \left(D_{k+1}\right)-\ln \left(D_k\right)\\ \ln \left(P_{k+1}\right)-\ln \left(P_k\right)\end{array}\right]$

    ${\mathrm{\θ}}_k=\left[\begin{array}{c}{\mathrm{\α}}_k\\ {\mathrm{\β}}_k\\ {\mathrm{\γ}}_k\end{array}\right],{\mathrm{\θ}}_{k+1}=\left[\begin{array}{c}{\mathrm{\α}}_{k+1}\\ {\mathrm{\β}}_{k+1}\\ {\mathrm{\γ}}_{k+1}\end{array}\right]$
18. 18. one kind control continuous hot-dipping galvanizing handle in the system of coating weight on the steel band, wherein be provided with first and second air knives, the coating weight of the airstream control steel band by winding-up predetermined pressure on the steel band that passes zinc liquid coating bath, described system comprises:

    The first Coating Weight Control device, it measures steel bands and first and second air knives distance value between each in a plurality of measurement point, and change the position at the two ends of each air knife with a plurality of distance values of measuring, thus steel band is aimed at parallel with each air knife, and maintenance steel band and each air knife are equidistant;

    The second coating control device, the welding portion of two steel bands by preceding and pass through after the scheduled time in, change each position of first and second air knives according to the thickness difference of these two steel bands, thereby proofread and correct moving of traveling route;

    The 3rd Coating Weight Control device, its foundation changes jetting pressure in the coating weight of the hope of steel band and/or the variation of speed of feed;

    The air knife distance control device, welding portion by preceding and after the scheduled time, it regulates the position at first and second each two ends of air knife with the second Coating Weight Control device, at welding portion by the back with the first Coating Weight Control device, regulate each end positions of first and second air knives; With

    The air knife pressure control device, it is regulated from the jetting pressure of first and second air knives winding-up with the 3rd Coating Weight Control device.

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