Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
  • F16C32/0629—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a liquid cushion, e.g. oil cushion
  • F16C32/064—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a liquid cushion, e.g. oil cushion the liquid being supplied under pressure
  • F16C32/0644—Details of devices to control the supply of liquids to the bearings
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/0073—Accessories for calenders
  • D21G1/008—Vibration-preventing or -eliminating devices
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G1/00—Calenders; Smoothing apparatus
  • D21G1/02—Rolls; Their bearings
  • D21G1/0206—Controlled deflection rolls
  • D21G1/0213—Controlled deflection rolls with deflection compensation means acting between the roller shell and its supporting member
  • D21G1/022—Controlled deflection rolls with deflection compensation means acting between the roller shell and its supporting member the means using fluid pressure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor
  • F16C13/02—Bearings
  • F16C13/022—Bearings supporting a hollow roll mantle rotating with respect to a yoke or axle
  • F16C13/024—Bearings supporting a hollow roll mantle rotating with respect to a yoke or axle adjustable for positioning, e.g. radial movable bearings for controlling the deflection along the length of the roll mantle
  • F16C13/026—Bearings supporting a hollow roll mantle rotating with respect to a yoke or axle adjustable for positioning, e.g. radial movable bearings for controlling the deflection along the length of the roll mantle by fluid pressure

Definitions

• the invention relates to a roller for treating a fibrous web having a circumferential, mounted on a rotationally fixed axis hollow roll shell, wherein the annular space between shell and axis is divided by at least two axial seals in at least two chambers, which to achieve a desired roll deflection with Druckflui- the different pressure can be filled.
• the invention further relates to a method for preventing vibrations in a system constructed from this roller and a counter-roller.
• the speech is therefore of a in professional circles as “floating roller” or “S-roll” designated roller.
• these rolls are often used in narrower calenders (based on the web width, the so-called CD direction).
• the differential pressure in the two chambers is sufficient to achieve a deflection that substantially conforms to the curvature of the backing roll.
• the two longitudinal seals in an S-roll are known. They allow the different pressure build-up in a crescent-shaped chamber facing away from the nip and facing away from the nip. In many cases, they even allow a lifting movement of the jacket, without the tightness is lost.
• the oil which is supplied to the higher-pressure chamber from a roll neck side fed back via the second chamber at lower pressure. With broad calenders, this type of roll is generally no longer sufficient to achieve a desired transverse profile of the fibrous web, so that so-called "Nipco rolls" have to be used by the applicant, which are considerably more complex and involve a more complicated application.
• the measures described are therefore not suitable for S-rolls, to actively or passively combat vibrations of the roll shell in the range of 100 to 400 Hz, since the large volume of oil inside the floating roll prevents stiff coupling of the axis and rotating mantle.
• the additional air that is added to the system also prevents a sufficiently high oil rigidity in the range of> 900 N / mm 2 .
• DE 295 09 545 U1 discloses a roller with a vibration damper, in particular for producing or treating fibrous webs, e.g. Paper or board webs, known. It is also a roller with a stationary central axis and with a roller shell rotating about this central axis.
• a central axis In the central axis is a series of e.g. provided cylindrical pressure chambers which extend in the radial direction and each receive a radially displaceable support member.
• Each pressure chamber can be filled with a pressure fluid / transfers a hydraulic support force from the central axis via the support member on the roll shell, so as to be able to adjust a deflection of the roll shell targeted.
• a single elongated pressure chamber with a single elongated support element may be present.
• the object is achieved by the device with a roller, in which at least one actively controllable Kammervolumenver sectionseinrich- device is present.
• Such an actively controllable chamber volume changing device creates the possibility of achieving short-term pressure surges by changing the volume of the chamber filled with a pressurized fluid. These pressure surges can produce an antiphase oscillation and thus extinguish the pressure pulsation, which is caused by the first axis frequency or by the first contact natural frequency of the system. At least the volume change, which is caused by the Kammervolumenver- changing means, approximately 90 ° out of phase between the vibrations of the roll shell and the oscillation of the axis can be adjusted, so that an optimal damping is achieved. A useful damping is expected at a phase offset of at least 50 ° to 130 °.
• the actively controllable chamber volume changing device can generate active phase-shifted counter-vibrations from inside the S-roll, which lead to a significant reduction in the oscillating movements.
• the chamber volume changing means comprises a membrane.
• a membrane makes it possible to change the volume in a chamber easily and, above all, quickly and precisely. It is important that the volume of the chamber pulsating, so adapted to the occurring vibrations of the roller, can be changed.
• the membrane which may also be conceptually formed by a metal lid, is preferably round or quadrangular. Of course, composite materials made of plastic and metal are suitable for the membrane. In many cases, it makes sense to bias the metal membrane / the metal cover hydraulically, mechanically, piezoelectrically or by elastomeric materials or pressure accumulator.
• the membrane is movable in such a way that a chamber volume can be increased or reduced by 0.01-0.5%.
• a chamber volume can be increased or reduced by 0.01-0.5%.
• the membrane is sealed in a recess of the axis all around.
• a membrane that is sealed all around is particularly easy to implement. It can be between two rings be clamped gene or frets. Yet it still has the freedom to keep the membrane surface movable in order to be able to change the volume in a chamber. It is contemplated to bias the diaphragm over the pressure of the pressurized fluid in the chamber.
• the actuator can tie directly to the membrane and move it. As a result, vibrations in the roller can be countered very quickly.
• the actuator is capable of exerting pressure on the jacket with hydraulic, pneumatic or electromagnetic means. These agents are used in a proven manner and are relatively easy to handle and wear. Each calender also has a hydraulic, pneumatic and electrical supply anyway. However, it is particularly advantageous if the actuator comprises at least one piezoelectric element. The expansion of piezoelectric elements can be controlled quickly and precisely by electrical means.
• the piezoceramics are round or preferably rectangular in shape.
• the stack height is 5 to 100 mm.
• the power electronics are housed outside the roller in a control cabinet. Via a cable channel, a secure power supply can be ensured.
• the operating voltage of the actuator is +/- 10 to +/- 1000 V.
• the actuators can be grouped together, which are driven together by a power electronics or are individually controlled.
• the following solution is particularly easy to produce: a cut is made in the axis in the CD direction. Subsequently, an insert is made, which is inserted into the milling and includes all actuators.
• the pressure fluid conducted through the roller can additionally serve as a cooling medium for the actuators.
• the actuator in the recess is located radially further inwardly of the axis than the diaphragm.
• the actuator in the recess is located radially further inwardly of the axis than the diaphragm.
• the depression has a cooling fluid inlet and outlet.
• the pressurized fluid conducted through the roller can, in addition to its other tasks, serve as a cooling medium for the actuators.
• elaborate separate cooling bores with external connections are avoided.
• the pressure chamber is supplied via a pressure fluid line, in which there is a throttle element. Due to vibrations forces on the support element can be intercepted with the help of these chokes.
• the throttles thus additionally dampen in a passive manner and can be, for example, bore, sieve or annular gap throttles.
• a sensor arrangement is mounted on or in the roller, which is in communication with a control device which controls the at least one actuator.
• a control device which controls the at least one actuator.
• the most diverse measuring apparatuses are to be understood. This ranges from the tachometer to the acceleration or speed sensor of the vibrations, touching as non-contact.
• the signals of the measurement results are forwarded to a control device, which provides for an effective active activation of the actuator to intercept the roll jacket vibrations. It is favorable if the pressure exerted by the actuator pulsates via the diaphragm to the pressure fluid of a chamber during operation.
• the pulsation of the actuator preferably takes place in a specific frequency band. It is provided that the pressure exerted by the actuator pressure on the roll shell in operation at a frequency of 100 to 400 Hz pulsates.
• the rolls are usually intended to form a nip with a counter-pressure element, for example a second roll, in which a fibrous web can be treated. So that the profile in the nip is not unduly influenced, it is advantageous if the effective direction of all actuators does not go through the nip.
• the actuators are distributed symmetrically over the length and / or circumference of the roller. This avoids influences that unevenly affect the width of the fibrous web. If the roller only had a "belly" through the actuator on one side, the web would possibly be more compacted at this point than elsewhere.
• the object of the invention is achieved by the features of claim 12.
• the vibrations are avoided in a roller according to claim 1, characterized in that the volume of a chamber is changed pulsating.
• Each roller has a characteristic natural frequency and its own rigidity.
• these can be determined mathematically in a simple way.
• the stiffness and thus the natural frequency can be greatly changed, which in turn means that vibrations are avoided. It has been found that in systems, for example a calender, it is sufficient to avoid most oscillations resulting from natural frequencies with a pulsating volume change of the chamber by means of an actuator and a diaphragm.
• the expansion of the chamber volume changing device is regulated based on vibration measurements. This allows a more targeted and frequency-controlled pulsating pressurization on the roll shell, which dampens the resulting vibrations even better.
• the invention will be explained in more detail below with reference to exemplary embodiments with reference to the drawing. This shows in the figure
• the roller 1 works together with an indicated only as an arrow counter-pressure element 3, for example, a second roller to treat between them in a so-called nip a fibrous web.
• the roll 1 has a rotating roll shell 4 and a fixed axis 5. Between the two longitudinal seals 6 are provided, which share the annulus 7 in an upper chamber 8 and a lower chamber 9. These chambers are filled with a pressurized fluid, usually oil, under different pressure. As inlet and outlet channels of these chambers 8, 9 for the pressurized fluid, the channels 10 are provided. Different pressures in the chambers 8 and 9 allow the roller 1 a deflection which can be adapted to that of the counter-pressure element 3.
• the system of roller 1 and counter-pressure element 3 tends for a variety of reasons, such as unevenness of the treated
• an actively controllable chamber volume change device 2 is used for this purpose, which is housed in a recess 13 of the axis 5.
• the chamber volume change device 2 consists of a laterally sealed in the recess 13 membrane 12 and an actuator 1 first
• the actuator is composed essentially of piezoelectric elements 15, which can be controlled via power lines 16.
• the operating voltage of the actuator is +/- 10 to +/- 1000 V.
• the diaphragm 12 can be moved to increase the space in the chamber 8 in accordance with the vibrations or reduce. In this case, it is preferable to increase or decrease the chamber volume by 0.01-0.5%.
• the difference in pressure created thereby acts as a pulsating measure against the vibrations, either in antiphase to extinguish the vibrations, or out of phase by about 90 ° in order to damp the vibration.
• the chamber volume change device 2 thus actively works against the vibrations.
• the membrane 12 is held around the surface of the axis 5 within the depression 13 and is surrounded by an annular seal 14. sealed, so that the pressure from the chamber 8 can not act directly on the actuator.
• the chamber volume extends over the half-moon-shaped half annular space 7, up to the membrane 12. This active vibration damping can also be supported by chokes are not shown in the inlet or outlet 10 of the chambers arranged in the drawing.
• lines 17, 18 from the chambers 8, 9 to the actuator 1 1 are provided.
• the pressurized fluid which flows from chamber 8 via the line 17, past the piezoelectric element 15, flows through the line 18 into the chamber 9 with the lower pressure, accordingly also cools the actuator 1 1.
• a sensor arrangement 19 for measuring vibrations advantageously sends its measuring signals via a control line 20 to a control device 22, which in turn - indicated via the control line 21 - ensures that the chamber volume changing device 2 is supplied with a pulsating pressure to the pressure chamber space 8 such that the Oscillations of the system are reduced interfering.
• a counter-vibration with pressure on the jacket 4 is introduced via the chamber volume change device 2.
• Suitable sensors are acceleration sensors, capacitive sensors, pressure sensors, optical sensors, etc.
• the actuator 1 1 does not have its effective direction towards the nip formed with the counterpressure element 3. As a result, negative pressure influences of the chamber volume change device 2 on the treatment of the fibrous web are avoided. LIST OF REFERENCE NUMBERS

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Paper (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Treatment Of Fiber Materials (AREA)

Applications Claiming Priority (2)

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• 2010
  • 2010-05-31 DE DE201010029492 patent/DE102010029492A1/de not_active Withdrawn
• 2011
  • 2011-03-25 WO PCT/EP2011/054576 patent/WO2011151092A1/de active Application Filing
  • 2011-03-25 CN CN2011800326621A patent/CN102959257A/zh active Pending
  • 2011-03-25 EP EP11711514.7A patent/EP2577078A1/de not_active Withdrawn

Non-Patent Citations (1)

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