FI79393C - Procedure for measuring and regulating the straightness of the roller system of a supercalender - Google Patents

Description

79393 1 Method for measuring and adjusting the track straightness of a supercalender A method for measuring and adjusting the roll calibration of a supercalender by means of a supercalender 5

The invention relates to a method for measuring and adjusting the straightness of a supercalender roll, said roll comprising a capacity-compensated upper roll supported on the calendar body JO by external loading devices, i.e. upper cylinders for adjusting the line pressure level. intermediate rollers between the lower rollers.

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In the supercalender, the calender of the supercalender plays an essential role in the operation of the calendar. If the track is not straight, the paper path will be skewed because the rollers in the supercalender body will remain in position when the track rollers are in the skewed position. It is therefore an absolute prerequisite for operation that the rollers in the calendar frame and the rollers in the track must be in line with each other. During the lifting of the track, in particular the closing of the nip between the lower roller and the lowest intermediate roller, i.e. the lower flap, must take place in order to keep the contact surface pressures in the nip low. The same is true in principle 25 during the lowering of the track. In current structures, measuring track straightness, and in particular keeping track straight, has proven problematic in many cases.

It is an object of the present invention to provide a method which solves the problem described above and which avoids the drawbacks associated with current structures. To achieve this, the method according to the invention is characterized in that the method measures the straightness of at least one roll of the roller by means of position sensors mounted on the ends of said roll, from which control pulses are adjusted straight by adjusting the hydraulic control system of the roller.

The most significant advantage of the invention over the previously known solutions is that the method according to the invention makes it possible to adjust the track of the supercalender straight, i.e. to straighten it both during driving and during lifting the track. The method according to the invention is implemented with a simple and reliable control system. Other advantages and features of the invention will become apparent from the following detailed description of the invention, to which, however, the invention is not intended to be exclusively limited.

The following invention will be explained in detail with reference to the figures of the accompanying drawing.

Figure 1 is a schematic view of a supercalender track partially cut away and equipped with position sensors for carrying out the method according to the invention.

Fig. 2 corresponds to Fig. 1 a track equipped with a control system operating according to an embodiment of the invention.

Figure 3 shows an alternative embodiment to the solution shown in Figure 2.

In the figures of the drawing, the upper roll of the supercalender roll is denoted by the reference number 1. The upper roll 1 is a deflection-compensated, zone-adjustable roll 25 comprising a roll shaft 11 and a roll shell 12 supported relative to the shaft 11 by hydraulic (hydrostatic / hydrodynamic) load elements direction to the zones. In addition, at its ends, the roll shell 12 is mounted on the shaft 11 by end bearings (not shown).

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The shaft 11 of the upper roll is supported on the body of the supercalender by external loading slabs 14, i.e. upper cylinders, which are used to adjust the pressure level of the roll. The upper cylinders 14 are double-acting cylinders, so that on the one hand they can increase the line pressure level of the te-35 ** load in the desired manner and on the other hand they can reduce the load caused by the upper roller 1 to less than its own weight. The upper cylinder blades 14 can be advantageously used from a differential cylinder, in which case the leakage of the cylinders has no significant effect on the position of the roll shaft 11 or on the line pressure level of the roll.

The lower roll of the track is denoted by reference numeral 2 and also the lower roll is a belt-5 deflection-compensated deflection roll comprising a roll shaft 21 and a roll shell 22 rotatably supported on the roll shaft 21 by hydraulic loading elements 23. In addition, external loading devices 24, i.e. lower cylinders, can be arranged on the lower roller 2, by means of which the position of the lower roller 2 can be changed. A plurality of intermediate rollers are arranged in a conventional manner between the upper roll 1 and the lower 10 roll 2, of which the lower and upper intermediate rollers 3 and 4 are shown in the drawing figures. , i.e. the nip between the lower roll 2 and the lowest intermediate roll 3 with the reference mark Nj.

Position sensors 27 are mounted at each end of the lower roller shaft 21, as shown in Figure 1, which measure the position and straightness of the lower roller 2. In addition, corresponding position sensors 31 are arranged at each end of the lowest intermediate roller 3, which measure the straightness of said intermediate roller 3. The position sensors 31 can be arranged at the ends of any intermediate roller 3,4, but the most advantageous effect is obtained by placing the position sensors just at the ends of the lowest intermediate roller 3. The position sensors 27,31 are linear sensors, from which, according to the measurement data obtained, the track system is adjusted straight by the control system, as described in connection with Figures 2 and 3.

Figure 2 shows a first embodiment of a method according to the invention. According to Fig. 2, the hydraulic system of the track is provided with a hydraulic pump 6, which feeds the bellows medium 30 e.g. . According to Fig. 2, the bellows medium is fed to the lower roll load laths 24 through the control valves 25 and, accordingly, the pressure medium is supplied to the lower roll hydraulic load element 23 via separate control valves 26. As already stated, the load elements 23 of the lower roll 2 are divided into zones in the width direction of the roll, whereby the hydraulic system has its own control valves 26 for each zone.

4 79393 5 The hydraulic system of the track is equipped with a control computer 5 for controlling the operation of the system. correcting the straightness of the track during lifting the track by adjusting the pressures of the lower cylinders 24 via the lower cylinder control valve 25 so that the movement of the lower cylinders 24 can be synchronized.

During the run, when the track is closed, the track sensor 31 is measured with the position sensor 31 of the intermediate roller 3 and the zone pals (pressures of the load elements 23) of the lower roller 2 are adjusted by means of the load element control valves 26 so that a certain correction is made to the zone pressures.

In the embodiment of Figure 3, the adjustment of the straightness of the track is performed during the lifting of the track in the same way as already described in connection with Figure 2. Instead, the straightness adjustment performed while driving differs from that shown in Figure 2. In the embodiment of Figure 3, during the running of the track, fixed zone pallets are used in the lower roller 2, which depend on the desired clamping force as well as the desired profile. In order to adjust the track directly according to the control impulse received from the position sensors 27,31, separate hydraulic control circuits 30 are arranged on the upper cylinders 14, to which, under the control computer 5, Said inclined load is thus completely dependent on the control pulses of the position sensors. With an inclined load, the track can be adjusted straight.

The invention is not limited to the embodiments shown in the accompanying schematic figures, but the various embodiments of the invention may vary within the scope of the inventive idea defined in the appended claims.

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Claims (5)

6 79393 ^ Claims A method for measuring and adjusting the straightness of a supercalender roll, said roll comprising a deflection-compensated upper roll 5 (1) supported on the calendar body by external loading devices (14), i.e. upper cylinders for adjusting the line pressure level, a deflection-compensated, zone-adjustable lower roll 2 equipped with external loading devices (24), i.e. lower cylinders for changing the position of the lower roll (2) and several intermediate rollers (3,4) between the upper roll (1) and the lower roll (2), characterized in that at least one roll (1-4) of the roll is measured straightness with position sensors (27; 31) mounted on the ends of said roll, from the control pulses of which the roll is adjusted straight by adjusting the hydraulic control system of the roll. 15 Method according to claim 1, characterized in that during the lifting of the track, i.e. closing of the track, and correspondingly lowering of the track, the position of the lower roller (2) lifting cylinders or lower cylinders (24) is measured by position sensors (27) (27), the pressures of the lifting cylinders (24) are adjusted so that the movement of the lifting cylinders (24) can be synchronized. Method according to Claim 1 or 2, characterized in that during the running of the track and when the track is closed, the straightness of the track is measured by measuring at least one intermediate roller of the track; (3,4) straightness using position sensors (31) at the ends of said roll and using control pulses obtained from said position sensors (31) as a control variable, the roll is straightened by adjusting the zone pressures of the lower roll (2). Method according to Claim 1 or 2, characterized in that during the running of the track and when the track is closed the track straightness is measured by measuring the straightness of at least one intermediate roller (3,4) of the track with position sensors (31) at the ends of (1) 35 7 79393 Ί the pressures of the external loading devices, ie the upper cylinders (14), so that the track is straightened. 5 10 15 20 25 30 35 β 79393