FI94552B - Apparatus for measuring paper roll shape defects - Google Patents

Description

94552

APPARATUS FOR MEASURING THE DEFECTS OF A PAPER ROLL

The present invention relates to an apparatus according to the preamble of claim 1 for measuring shape defects in a paper roll.

Moving and otherwise handling the paper rolls coming from the paper machine's slitter causes ovals and other shape defects, so that the paper roll 10 arriving at the customer is no longer as round as it was when leaving the slitter. Newsprint in particular is sensitive to oval. For this reason, it is often necessary to measure the shape defects of the paper rolls.

15 Shape defects can be measured. with suitable measuring equipment. For example, a device sold under the name Radivarius measures the roundness of a roll of paper by drawing a roundness profile of the roll of paper at a distance of 0 to 160 mm from the end of the roll of paper. For the measurement, a hole 20 is cut from the rollers in the end flap at the sleeve and a measuring device is mounted in place of the pin. The measuring device has a centrally axed measuring arm which runs along the circumference of the roller. In the middle of the roll is a drawing device which, as the measuring arm runs along the circumference, simultaneously draws the circumference of the roll on paper (in a smaller dimension-25 formula). The roundness of the roll can then be determined from the image.

Ko. the measuring device also measures the eccentricity of the roller. The disadvantage the device has the fact that the roll cannot be measured from a very long end, in which case it is not possible to get an image of the ovality of the roll along the entire length of the roll. In addition, the when using the device, the 30 packed rolls always have a breakable end tag at the core.

The object of the present invention is to eliminate the drawbacks of the known measuring devices and to provide an electronic measuring device which is better than the current devices for measuring the shape defects of a paper roll. The measuring apparatus according to the invention has gripping arms which adhere to the circumference of the paper roll, by means of which the apparatus can be attached to the paper roll. In addition to its 2 94552, the apparatus includes a measuring unit with a distance sensor which rotates a circle outside the circumference of the paper roll at different heights and non-contact measures the distance of the measuring unit from the circumference of the roll. Ko. the measuring unit 5 is mounted on a vertical mounting arm, which in turn is mounted on a height-adjustable horizontal mounting arm, which is axially mounted on a frame in the center of the end of the roller of the apparatus. The position of the measuring device on the circumference of the roller is measured by a position-10 sensor on top of the frame. The measuring unit can be connected to a measurement data processing system, such as a PC, from which the measurement results can be printed. Instead of gripping arms, the measuring equipment can be attached to the paper roll by means of a pin in the middle. The detailed features of the invention are set out in the appended claims.

With the apparatus according to the invention, the ovality of the circumference can be measured very accurately, and from the height of the entire roll. When the distance measurement takes place electronically and non-contact, for example by means of an ultrasonic sensor, the measuring unit is wear-free, accurate and simple in its mechanical structure. When the equipment is fastened either by means of gripping arms or by a central pin, the measurement can distinguish the factors due to the oval of the circumference and the eccentricity of the roller.

25 - When attaching the equipment by means of gripping arms, there is no need to break the packaging of the packed roll at all.

In addition, when using the gripping arms, the equipment does not need to be mechanically centered exactly in the middle of the roller, but the centering is done programmatically by means of a measuring unit.

The measurement itself, as well as the processing of the measurement results, takes place very quickly, and it is possible to print the results in the desired format, for example graphically.

In the following, the invention will be described in more detail by way of example with reference to the accompanying drawings, in which 3,94552

Figure 1 shows an apparatus according to the invention.

Figure 2 shows the engagement of the gripping and fastening arms with the frame.

5

Figure 3 shows a graphical representation of the measurement results.

Figure 1 shows an apparatus according to the invention for measuring shape defects in a paper roll. The apparatus has a circular body 3 to be attached to the upper end of the pape-10 roller 1, which is upright on the base 2. tightening gripping jaws 5 (Fig. 2). The horizontal shaft 6 fixed to the upper edge of the body 3 is pivotally shafted by means of a fastening part 7 of a horizontal support arm 9 of the measuring unit 8 with holes corresponding to the pins 10 of the fastening part 7 for length adjustment, so that the distance of the measuring unit 8 from the side of the paper roll 1 can be adjusted. To the second fastening part 12 at the end of the horizontal fastening arm 9, in turn, a height-adjustable vertical fastening rod 14 is fastened by means of clamping parts 13, at the lower end of which the measuring unit 8 is placed. During the measurement 25 - the measuring unit 8 is rotated manually around the roller 1.

At the upper end of the body shaft 6, a pulse sensor 15 measuring the position of the measuring unit 8 on the circumference of the roll is placed. The distance 30 from the surface of the paper roll 1 is measured by an ultrasonic sensor 16 at the lower end of the measuring unit 8.

The power supply of the measuring unit 8 and the pulse sensor 15 is a battery 17 on top of the pulse sensor 15. The measuring unit has 35 microprocessor-based electronic units for reading and storing measurements. In addition, it has the necessary actuators 18 (buttons, indicators, e.g. LEDs) for performing 1 94552 measurements. In addition, the apparatus has the necessary cables 19 for connecting the pulse sensor 15 and the battery 17 to the measuring unit 8 and for connecting the measuring unit 8, if necessary, to a microcomputer 20 for processing and printing measurement data, to which the necessary plotter and other printing can be connected.

The software running on the microcomputer 20 consists of a user interface, a data transfer program, measurement data processing algorithms, and measurement data graphics programs. The measurement data processing algorithms are based on algorithms known per se.

The body 3 can also be fastened to the roller 1 (as an alternative 15 to the gripping arms 4a to 4c) to the sleeve 21 in the middle of the roller 1 by a push-in pin 22.

When attaching the measuring equipment by means of gripping arms 4a to 4c, the principle of the algorithm is to fit the cylindrical surface of the paper roll 1 as a model so that the sensor distances calculated from this model deviate as little as possible from the measured distances from the actual roll 1 surface. Two coordinate systems can be used in the calculation: one is the coordinate system attached to the measuring-25 equipment and the other is the coordinate system attached to the roller 1 model. The position and positional relationship between the roller model and the coordinate systems of the measuring equipment can be expressed e.g. in a known manner by means of a rotation matrix and translation, whereby the positions of the sensor 30 in the roller model coordinate system can be calculated and deviations from the circle can be calculated and printed. If, on the other hand, the pin 22 is used in the fastening, the deviations from the circular shape are calculated by an algorithm in which the coordinate system of the roller model is always in the same position and at 35 positions as the coordinate system of the measuring device.

5,94552

The measurement is performed at different cross-sectional levels of the roll (by adjusting the height of the measuring unit 8) as follows: 1. Attaching the body 3 to the paper roll 1.

5 2. Defining the measuring point, for example with the help of potentiometers included in the electronics unit. The parameters to be given can be, for example, the position of the distance sensor 16 in the radial direction and the position in the longitudinal direction of the roller 1.

10 3. Start measurement with the "start measurement" button on the controls 18 / the indicator light on the button starts flashing.

15 4. Rotate the measuring tool until the zero point is found.

A steady light indicates that a zero point has been found as a reference point.

5. Carry out the measurement by rotating the measuring unit 8 around 20 rolls of paper 1. The indicator light goes out and the measurement data is saved the next time the zero point is exceeded. If the measuring unit 8 is rotated too fast, the measurement is discarded and the user is notified of the event by a flashing LED. The measurement must be restarted.

25 · 6. After a successful measurement, move to the next measurement level.

7. When the measurement of the roller 1 has been completed, the measuring unit 8 30 is connected to the microcomputer 20 and the decompression of the measurement data is started by pressing the data transfer button. Ko. the LED on the button indicates the status of the communication connection, before starting the communication, the microcomputer program will ask the user to define a file where the measurements will be stored sequentially in measurement levels.

6 94552 8. For the measurement processing algorithm, a file is defined from which the measurements are read, as well as a result file in which the deviation data generated by the algorithm is stored. The processing algorithm is selected according to the method of mounting the measuring equipment.

5 9. The user-selected result file (= deviation file generated by the algorithm) is displayed on the microcomputer screen as a graphic image. It can be saved to a file selected by the user and printed, for example, with a plotter. Fig. 3 shows an example of such printing, in which the height [m] and the deviation [mm] of the measuring unit 8 are shown on the vertical axis and the position [degree] on the horizontal axis.

It will be clear to a person skilled in the art that the various embodiments of the invention are not limited to the example given above, but may vary within the scope of the claims set out below. Thus, instead of an ultrasonic sensor, another non-contact distance measuring sensor can also be used, e.g. a laser sensor.

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Claims (4)

Apparatus for measuring mold defects of a paper roll (1), the device comprising a frame (3) placed in the end of the paper roll (1), characterized in that the device further comprises gripping arms (4a, 10) connected to the frame (3). 4b) which grip the circumference of the paper roll (1) and with which the body (3) can be attached to the paper roll (1), a measuring unit (8) movable along the side of the paper roll (1), provided with a spacer (16) which measures without contact the distance from the side of the roller (1), which measuring unit with a fastening arm unit (9,14) is fixed to the body so that the height of the measuring unit can be controlled and which is shafted in the body (1) so that it can describe a path around the circumference of the roller, An angle sensor (15) which measures the position of the measuring unit (8) in the path around the roller circumference, and a data processing unit (20) known per se which can be connected to the measuring unit and which processes and outputs the measurement data of the sensor . Device according to claim 1, characterized in that the length of the gripper arms (4a, 4b) can be adjusted and that the arms at the ..30 ends are provided with gripping heads (5) which are fastened to the paper roll. Device according to claim 1, characterized in that the fastening unit is provided with a horizontal arm (9) whose length can be adjusted, whereby the distance of the measuring unit (8) to the side of the paper roll (1) can be adjusted. Device according to claim 1, characterized in that the body (3) is provided with a fastening element (22) which can be fitted in the middle (1) of the roller (1) and the body (1) alternatively can be are fixed in the roll (1), and that in the data processing unit (20) there are two algorithms for processing measurement data, one for each fastening method. • «• · Il Utit liiti 1 1 IM. 1