DE2351525A1 - Bar length monitoring system for rolling process - evaluates finished length from emerging length before the whole bar is finish rolled - Google Patents

Abstract

Rolled material is measured by the monitoring appts. during the actual rolling process, and it analyses the material before it emerges from the rolling plant and reaches a downstream connected cutter. This arrangement yields early and accurate information about the material still to be rolled and it controls the machinery used for cutting the material to required lengths. The appts. predicts the finished length while it is still rolling and actuates means for preventing excessive cooling of the rolled material and also yields advance information about the material losses in the form of cut off lengths at the start and finish, to ensure economical parting of the finished length into commercial lengths. The distance between the rolling plant and cutter is very short and the hot material leaves the rolling plant into the shears. Photoelectric cell are arranged downstream of the rolls, and a photoelectric cell arranged upstream of the rolls reports the start and end of a bar.

Description

BROWN, BGVER! &

WAfINHtIM.

Mp.no. 654/73 Mannheim, October 9, 1973

PAT- NL / Fl.

"Procedure for determining rod length"!

The invention relates to a method for rod length. averaging during the rolling operation and is predominantly appli ^~: dung in cold or hot rolling mills or in the areas where ί a material tapering in the work sequence occurs. j

It is known to record the lengths of materials when
they come out of the processing machine. The finished result can only be checked when you leave the machine. ;

Data is also known in a computer, e.g. target data on ' Enter output, dimensions of the raw workpiece and running speed and from this information a rod length; make a determination at the exit. ί

Disadvantage of this method is in addition to a not sufficient Ge ™ \ especially accuracy of great effort. The inaccuracy of the; The above-mentioned method is achieved through the precalculations ■ of the length of the rolled stock exiting the rolling mill, the dimensions or the weight of the incoming rolled stock. Included
namely, an unpredictable loss through cropping and tinder must be taken into account. · "J

- i

In other methods, a length measurement by driver or measuring roller, pulse generator and counter or by integrating the
Rolling speed made. But here, too, a measurement result is only available when the end of the material is out

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the roll stand in question has run.

This is too late for the control of subsequently arranged shears or the distance between the roll stand and the shears must be increased which means additional effort.

The object of the invention is, even during the actual rolling process, taking into account the longitudinal extension of the material to carry out a measurement of the rolling stock and to carry out an assessment before the material leaves the roll stand: increase in order to achieve a favorable division into partial lengths and end scoop lengths for a downstream working machine; aim. ■

According to the invention, this is achieved in that the determination of the finished length emerging from the roll stand takes place before the end of the finished length has reached the roll stand and that the finished length is calculated from the distance between Roll stand and working machine forming constant length and a remaining length, the exiting remaining length by integration the material exit speed or by counting pulses of the corresponding frequency in a certain time is determined. In addition to the instantaneous measured values, only one constant from empirical values is used to determine the time Determinations or from measurements of the previously run bar using the same program. The remaining length determination is both possible in digital and analogue technology. If a process computer is available, the remaining length is determined from the instantaneous measured values, constant intervals and only one constant from empirical determination or from measurement of the previously run baton in the same program.

One advantage of the method according to the invention is the early, precise knowledge of the waIz-

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_ 3 -

good. This allows for quick control of a subsequent connected work machine, such as scissors or saw, allows. The distance between the roll stand and the working machine can can be chosen to be very small, which in turn means small hall dimensions and roller table length. It is also advantageous that by calculating the production length in advance in the rolling mill; prepare too great a cooling of the rolling material on the wide! ren way is avoided and ^ that material losses in the form of beginning and end crop lengths are known because an exact Cutting of tail lengths is made possible. The new ver: Driving also enables inexpensive and economical; Division of the finished length into standard part lengths. I.

An embodiment of the proposal according to the invention is explained in more detail below with reference to the drawings. j

Fig. 1 shows the spatial arrangement of the roll stand, shears ^; and photocells during '

2 shows a block diagram of the entire electronic sequence. \

For processing by cooling bed shears Λ, the still glowing material leaves the roll stand 2. Behind the roll stand 2, the photocells 3 and 4 are arranged and in front of the roll stand there is the photocell 5. These photocells ^! are illuminated or deflated by the glowing material. In front of the last stand 2 in a possibly row of one behind the other; The photocell 5 reports the beginning and end of a moving bar or pipe when the rolling stands are switched on. This photocell 5 has the. Distance c. in front of the scissors 1.;

The finished length c, from the point in time of the photocells 5 - defloration up to scissors 1 is to be determined. This length c is greater than the distance c ^ (photocell-scissors) because of the Strek ™ effect during rolling, c, is the distance between the roll stand 2

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η- * » ac * / 17Ο 11r

I and the scissors 1. The finished length c is determined while the I tip of the rod or tube passes through the distance c ^, i.e. as soon as the tip has passed the photocell 4 and the

: Stand speed n ~ is calibrated _{as ν Λ.} ; (J w ι

I The procedure therefore assumes that when a WaIzi rods or pipe, the first meters are extended during the rolling process by the same factor j as the last meters, i.e. * the machining process must be continuous.

The method according to the invention allows both analog and digital signal processing.

To determine the finished length c, several Auxiliary variables can be determined.

In a measuring device shown in Fig. 2, the

i walking speed ν . of the rolling stock from the roll stand! measure up. In most cases, this measuring device for ν „I is already available within the scissors control, ν. is determined, j while the tip of the rod passes through the calibration path, which is delimited by the photo cells 3 and 4. '■.

In a device, not shown, it is measured at what speed ν ~ the rod or tube end runs into the roll stand 2, ν 2 is determined by the speed n _{& of} the roll stand 2. ^;

^V w2 ^{= K} 2 * ⁿ G.

The constant factor Kp is required for a rolled profile or rolling program to be determined only once.

If several roll stands are arranged in a row for the processing of thin materials and the distance between the roll stand : 2 ζια a next scaffold in front of it is large enough, so

. - .5 -. BATH ORIGINAL

509817/0119

a further photocell is attached in front of the photocell 5, so that with this distance between the two photocells one The calibration distance is given to determine νp.

Is only a small space to attach another photocell Given at the distance of a calibration section in front of the photocell 5, the distance Cq between photocell 5 and roll stand 2 can be used as Serve calibration section, provided that the motor current of the VaIzgerüstes it can be seen when the material is leaving the stand very little material taper, the constant factor Kp is set on a potentiometer or on a decade selector switch set by hand. Kp depends on the roll diameter and from the ¥ alz rod profile.

j The time it takes for the end of the rod to move with the speed Walking from photocell 5 to stand 2 is called tp. ^

What is required is the remaining bar length c _R , which does not run into the frame during this time tp, but which runs out of the frame. This time t, -, could easily be determined at a constant speed of the rolling stands lying in series by measuring the respective previous rolling rod. However, this is not possible due to the different working speeds. Only the most necessary data should be taken from a previous staff to calculate tp, whereas as much information as possible should be used from the staff currently running. Therefore * the constant Kp, which depends on the respective rolling program, is used from the previous member.

tp should be determined early. For this purpose, the speed v is immediately after exposure of the photocell 5. _<? = K · ru applied to the in Fig. 2. integrator shown. 6

50 9817/01 19th

The integrator 6 runs until it has simulated the path of the rod between photocell 5 and frame 2. This result is detected by the comparator 10 shown in FIG. This time t ~, during which the integrator 6 is running, j is stored in the counter 7. For this purpose, 8 pulses of constant frequency are sent to the counter 7 from an oscillator. The j counter thus displays or stores the result for the j throughput time of the yeg C _n . Here, C _{n means} the distance ι υ υ

j from the photocell 5 to the roll stand 2. The time t _o "remains in

t C

j Counter 7 is saved until it is further evaluated, namely as soon as the tip of the rod or pipe has passed the photocell 4 and the stand speed n ~ is calibrated as v ,,,.

j Then counter 7 runs up again at its constant frequency

Zero, what with the coincidence circuit shown in Fig.2

j is detected.

While counter 7 counts to zero, that is to say for t "long, 11 pulses of frequency f ^ are counted in a further counter 11, f ^ is the exit speed ν . of the rod or pipe proportionally. The counting result is the remaining length you are looking for

^C R - { ^f 1 ^German
O

If counter 11 is not started with zero, but with c, the constant scaffolding-scissors distance, its final value c, + c _{R is} the desired finished length c

c = c _R + C ₃

The finished length c as the end value of the counter 11 remains stored until after the photocell 5 has been removed for the final evaluation is queried.

The integration c-, =] ν .. · dt can also be done in analog technology

take place, as well as the addition c = c _R + c ^. However, since the result c must be stored until the photocell 5 is released, digital signal processing is preferable.

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In a further embodiment of the method according to the invention, a computer, which may already be in the system is installed, find application. This enables the task of calculating the finished length c. To be carried out using simple relationships

be solved.

By changing it you can easily see the finished length you are looking for.

O = O _{3 +} C ₀ ^

^ w2

CC ₃₊ C ₀

ü c 1 1177 ιη.ηη.'Κ · ρι

17/0119

Claims (4)

- 8 claims 1. Process for the rod length determination during the rolling operation, boiled characterized. Hen characterized in that the determination of the emerging from the roll stand (2) finished length (c) occurs before the end of the finished length reaches the roll stand (2). 2. The method according to claim 1, characterized in that the finished length (c) is calculated from a distance between the roll stand (2) and the machine (1) forming constant _{length (c v} ) and a remaining length (c _R ), the exiting Remaining length is determined by integrating the material exit speed (v y. ) Or by counting pulses of the corresponding frequency in a time (tp). 3. Method according to claim 1 and 2, characterized in that that for the determination of the time (tp) apart from the instantaneous measured values only one constant (jip) from empirical Determinations or from measurements of the previous staff of the same program is used. 4. The method according to any one of claims 1 to 3> characterized in that the determination of the remaining length (c _R ) can be carried out both in digital and in analog technology. 5. Method according to one of Claims 1 to 4, characterized in that, if a process computer is present, the remaining length (c _R ) is determined from the instantaneous measured values (v * and n _G ), constant distances (c-7 and Cq) and only a constant (Kp) from empirical .. determination or from measurement of the previously run bar in the same program takes place. 1 7/01 19 Blank page