EP2286025B1 - Shaking device - Google Patents

Abstract

The invention relates to a shaking device (10) for moving a member (12) back and forth along an axis (14) thereof, in particular a roller of a machine for producing and/or treating a fiber web. In the shaking device, the member (12) is coupled elastically to a counterweight (16) for the purposes of forming an oscillating system, and means (18) are provided for driving the oscillation system, which comprises the member (12) and the counterweight (16), at the resonance frequency thereof.

Description

The invention relates to a shaking device for reciprocating a roll of a machine for producing and / or treating a fibrous web along an axis of the roll. The fibrous web may in particular be a paper or board web.

In such shakers, it may happen that reaction forces are introduced into the foundation. Another problem is that a relatively high energy consumption can result.

From the DE-PS 681 896 already a shaking device for long-screen paper machines is known, in which the forming table is elastically connected to a balance weight, whereby a two standing in resonance masses comprehensive oscillating system is formed.

At one of the WO 98/35094 A1 known shaking the body in question is coupled with two eccentric drives whose eccentric positions are adjustable to adjust the stroke of the body movement against each other. A comparable shaking device is also in the EP 1 624 102 B described.

From the EP 0 635 601 A1 is a Schüttelbock for shaking heavy rolls of a paper machine known in which a vibration motor is connected via a connecting element with the mass to be shaken, which in Direction of the forced movement controllable, variable in length and in particular is elastically deformable.

In the EP 0 500 765 B1 a resonant oscillator is described, which comprises an active vibrator part which is in contact with a passive vibrator part of greater length, which mainly determines the resonant frequency and consists of a liquid column contained in a resonant tank, whose amount to change the resonant frequency by an adjustable Part is continuously changeable.

In a resonant oscillator described in DE-GBM 1 982 687 one or more damper devices are provided to change the amplitude in addition to energy-storing resonant springs whose damper members allow a variable damping.

The invention has for its object to provide an improved shaker of the type mentioned. It should be ruled out in a simple and reliable manner, in particular substantially that reaction forces are introduced into the foundation. In addition, the energy consumption should be reduced to a minimum.

According to the invention, this object is achieved by the features of claim 1.

Thus, there is provided a shaking device for reciprocating a roller of a machine for producing and / or treating fibrous web along an axis of the roller, in which the roller is resiliently coupled to form a vibration system with a counterweight. In addition, means are provided in order to drive the vibration system comprising the roller and the counterweight at its resonance frequency. A practical area for the Resonance frequency can be between 3 and 20 Hz, in particular between 5 and 10 Hz.

On the basis of this training, it is achieved, inter alia, that no reaction forces disturbing reaction forces are introduced into the foundation. In addition, the energy consumption for driving the shaker is significantly reduced.

With the roller, possibly together with the piston rod, on the one hand and the counterweight on the other hand results in a kind of resonant oscillator with two masses.

According to the invention a aligned with the roll axis hydraulic cylinder / piston unit is provided, the piston with the roller, coupled and the cylinder is movably mounted along the roll axis to form the oscillating counterweight along the roll axis, wherein the roller on both sides of the piston provided enclosed volumes of particular synchronous cylinder / piston unit resiliently, for example hydraulically coupled with the counterweight comprising the cylinder.

The two elastically coupled together masses can oscillate in the vibration system formed against each other. For practical reasons, preferably the same or approximately the same masses are provided. However, the two elastically coupled together masses can also be in a mutual ratio of 3: 1 to 1: 3.

The cylinder of the cylinder / piston unit expediently comprises a shell which increases the mass, in particular a concrete casing. In this case, the cylinder with the sheathing material, preferably concrete, cast around.

The adjusting springs effecting the elastic coupling can therefore be realized, in particular, as pure oil springs by the enclosed volumes in a particularly uniform hydraulic cylinder.

As already mentioned, the hydraulic oscillator is preferably operated at the natural or resonant frequency.

The drive means of the shaking device advantageously comprise means for the cyclical pressure supply of the cylinder / piston unit. In this case, the drive means of the shaking device may in particular comprise a servo valve.

According to a preferred practical embodiment of the shaking device according to the invention, the cylinder / piston unit can be acted upon via the drive means of the shaker so that energy losses caused by damping and / or friction are compensated again by a corresponding pressure increase, in particular at the maximum pressure at the reversal point. The associated increase in volume can be compensated for example after half a path length (π), that is at zero pressure at the reversal point.

The cyclical pressure supply can take place in particular via the servo valve.

The drive means of the shaking device preferably comprise a control and / or regulating device, which may be provided in particular for controlling the servo valve.

It is also particularly advantageous if the drive means of the shaking device comprise displacement sensors for detecting the stroke of the roller and / or the stroke of the counterweight. The relevant path signals can then be supplied to the control and / or regulating device.

It is also of particular advantage if the control and / or regulating device provided in particular for controlling the servo valve is designed so that the excitation frequency with which the oscillation system is acted upon is automatically determined from the reference frequency in defined steps is varied up and / or down until the sum of the strokes of the roller and the counterweight has reached a maximum. In this case, the predetermined, for example, computational frequency can be varied in particular in small steps.

Furthermore, the resonant frequency of the vibration system can be permanently or temporally checked by a minimum variation (+/-) of the predeterminable frequency and thus an associated total stroke change. Here, the predetermined frequency is preferably the changing circumstances, such as temperature or. Friction conditions, adaptively adaptable.

The control and / or regulating device can in particular also be designed so that the travel and the actuating time of the servo valve are kept constant during the variation of the exciter frequency.

This will then automatically the exact resonance frequency can be found.

According to an expedient practical embodiment, the control and / or regulating device is designed so that after determination of the resonant frequency of the vibration system, the stroke of the counterweight is defined by the preferably supplied at the reversal point or in the reverse range of the cylinder / piston unit volume. In this case, the control and / or regulating device may in particular be designed such that the cylinder / piston unit is supplied with a volume corresponding to a respective desired stroke value specification.

Thus, if the exact resonance frequency is found via the control and / or regulating device, the stroke is defined by the volume preferably supplied at the reversal point or in the reversal region. From the control and / or regulating device, the amount is set according to the Hubsollwertvorgabe.

It is particularly advantageous if the control and / or regulating device is designed so that the resonant frequency of the vibration system for adjusting the shaking frequency via an on and off preferably from the same volume on the two piston sides of the cylinder / piston unit is variable ,

The variation of the natural frequency can thus take place by switching on or off of preferably equal volumes on both sides of the piston (four-way valve). Thus, the shaking frequency can be set gradually.

According to an alternative advantageous embodiment, the volumes on the two piston sides of the cylinder / piston unit can be varied continuously via parallel movable hydraulic cylinders. In particular, both volumes of the two hydraulic cylinders are simultaneously adjusted by equal amounts.

The counterweight can be held by two adjustable Justierfedern in or about in the middle of the total stroke.

If a leak-free oil system is assumed, the energy loss can also be supplied by other means. For example, the roller forming the mass or the counterweight can be excited to oscillate from the outside ("pushing"). For this purpose, for example, so-called mechanical shakers, hydraulic cylinders and / or electromagnets can be used. In this case, the control via the servo valve is eliminated. The method described for the automatic determination of the resonance frequency can also be used.

In the case of a leak-prone oil system, the leakage quantity must be replaced by a subsequent dosing so that the trapped volumes are kept approximately constant. Leakage is detected when the sum of the strokes of the roller and the counterweight becomes smaller and / or the resonance frequency drops with the same loss energy supplied.

In principle, the hydraulic adjusting springs can be replaced by adjusting springs of any kind. As far as the loss energy is concerned, this can be compensated by pushing, for example. For a defined frequency, a mechanical system with adjusting springs can be realized. By switching on and off further adjustment springs frequency jumps can be realized.

Fig. 1

eine schematische Darstellung einer beispielhaften Ausführungsform einer erfindungsgemäßen Schüttelvorrichtung;

Fig. 2

ein Diagramm, in dem für eine beispielhafte Ausführungsform des hydraulischen Resonanzschwingers der Schüttelvorrichtung gemäß Figur 1 der Zylinderdruck sowie das Totvolumen über der Frequenz angegeben sind; und

Fig.3

ein Diagramm, in dem für eine weitere beispielhafte Ausführungsform des hydraulischen Resonanzschwingers der Zylinderdruck sowie das Totvolumen über der Frequenz angegeben sind.

Further features and advantages of the invention will become apparent from the drawing; in this show:

Fig. 1

a schematic representation of an exemplary embodiment of a shaking device according to the invention;

Fig. 2

a diagram in which for an exemplary embodiment of the hydraulic resonance oscillator of the shaker according to FIG. 1 the cylinder pressure and the dead volume are given over the frequency; and

Figure 3

a diagram in which are given for a further exemplary embodiment of the hydraulic resonance oscillator, the cylinder pressure and the dead volume over the frequency.

Fig. 1 shows a schematic representation of an exemplary embodiment of a shaking device 10 according to the invention for reciprocating a mass m ₁ having a roller 12 along an axis 14 thereof. The roller 12 is a Roller of a machine for producing and / or treating a fibrous web, in particular paper or board web.

The roller 12 is spring-elastically coupled to a counterweight 16 for forming a vibration system. In the present embodiment, the two masses of the roller 12 and the piston 22 on the one hand and the counterweight 16 on the other hand at least substantially the same size, ie m ₁ ≈ m ₂ .

In addition, means 18 are provided to drive the roller 12 together with the piston 22 and the counterweight 16 comprehensive vibration system at the resonant frequency.

In this case, an aligned with the roll axis 14 hydraulic cylinder / piston unit 20 is provided, the piston 22 with the roller 12 and mechanically coupled and the cylinder 24 is mounted to form the oscillating counterweight 16 along the roll axis 14 movable. In this case, the roller 12 via the both sides of the piston 22 provided enclosed volumes V _L , V _{R of} the preferably uniform cylinder / piston unit 20 is resiliently coupled to the cylinder 24 comprehensive countermass 16. The cylinder 24 of the cylinder / piston unit 20 may comprise a mass-increasing shroud, in particular concrete sheathing. In this case, the cylinder 24 may be cast around with the sheathing material, preferably concrete.

The drive means 18 of the shaking device may in particular comprise means for the cyclical pressure supply of the cylinder / piston unit 20.

In this case, the drive means 18 of the shaking device, in particular for the cyclical pressure supply of the cylinder / piston unit 20, may comprise a servo valve 26.

The cylinder / piston unit 20 can be acted upon by the drive means 18 of the shaking device in particular so that caused by damping and / or friction energy losses are compensated by a corresponding pressure increase, in particular at the maximum pressure at the reversal point. The associated increase in volume can be compensated again after about half a wavelength (π), that is to say at zero pressure at the point of reversal.

As already mentioned, the cyclical pressure supply preferably takes place via the servo valve 26.

In particular, for driving this servo valve 26, the drive means 18 of the shaking device may include a control and / or regulating device 28.

In addition, the drive means 18 of the shaker device can have displacement sensors 30, 32 for detecting the stroke of the roller 12 and / or the stroke of the counterweight 16.

The control and / or regulating device 28, which is provided in particular for activating the servo valve 26, can also be embodied such that the frequency of excitation, which is applied to the oscillation system, is automatically determined by starting from a predefinable frequency f in defined small steps is varied up and / or down until the sum of the strokes of the roller and the counterweight has reached a maximum.

Furthermore, the resonant frequency of the oscillation system can be permanently or temporally checked by a minimum variation (+/-) of the predeterminable frequency f and thus an associated total deviation change. In this case, the predefinable frequency f is adaptively adaptable to the changing circumstances, such as temperature or friction conditions.

In this case, the control and / or regulating device 28 may in particular also be designed so that the actuating path and the positioning time of the servo valve 26 are kept constant during the variation of the exciter frequency.

In particular, the control and / or regulating device 28 may also be designed such that after the resonant frequency of the vibration system has been determined, the stroke of the countermass 16 is defined by the volume supplied preferably at the reversal point of the cylinder / piston unit 20.

In particular, such an embodiment of the control and / or regulating device 28 is also conceivable, in which the cylinder / piston unit 20 is supplied with a volume corresponding to a respective desired stroke value preset s.

In addition, the control and / or regulating device 28 may in particular also be designed such that the resonant frequency of the vibration system for adjusting the shaking frequency can be varied by connecting or disconnecting equal volumes on the two piston sides of the cylinder / piston unit 20.

In principle, the volumes can also be varied steplessly by parallel movable hydraulic cylinders. In particular, both volumes of the two hydraulic cylinders are simultaneously adjusted by equal amounts.

The counterweight 16 can be held via two adjustable Justierfedern 34, 36 in or approximately in the middle of the total stroke.

If a leak-free oil system is assumed, the energy used to compensate for the loss energy can also be supplied in another way. For example, the mass 12 comprising the roller 12 or the counterweight 16 can be excited from outside to oscillate (pushing on). There are, for example, so-called mechanical shakers, hydraulic cylinders, electromagnets and / or the like conceivable. The control via the servo valve 26 is omitted in this case. The method described for the automatic determination of the resonance frequency can also be used.

In the case of a leak-prone oil system, the leakage quantity must be replaced by a subsequent dosing so that the trapped volumes are kept approximately constant. A leakage is detected when the sum of the strokes of the roller 12 and the counterweight 16 is smaller and / or the resonance frequency drops at the same supplied loss energy.

In principle, the hydraulic adjusting springs can be replaced by adjusting springs of any kind. As far as the loss energy is concerned, the energy required for compensation can be introduced into the system, for example, by pushing. For a defined frequency f, a mechanical system with adjusting springs can thus be realized. By adding additional Justierfedern frequency jumps can be realized.

In the diagram according to Fig. 2 are for an exemplary embodiment of the example in the Fig. 1 reproduced hydraulic resonance oscillator, the cylinder pressure and the dead volume over the frequency indicated. Here, the present embodiment is defined by the following values: Mass of the roll 12 3000 kg Counterweight 16 3000 kg, eg concrete, D = 1.4 mx 1 m Walzenhub 20 mm Effective piston surface 0.006 m ²

In the diagram according to Fig. 3 For a further exemplary embodiment of the hydraulic resonance oscillator, the cylinder pressure and the dead volume over the frequency are indicated. Here, the present embodiment is defined by the following values: Mass of the roll 12 3000 kg Counterweight 16 3000 kg, eg concrete, D = 1.4 mx 1 m Walzenhub 10 mm Effective piston surface 0.0123 m ²

So there are two mutually oscillating masses, namely in particular the roller 12 and the counterweight 16, coupled for example via hydraulic springs, wherein preferably the same masses are provided. The counterweight 16 may include, for example, a cast with concrete hydraulic cylinder. The springs are realized, for example, as pure oil springs, that is to say by the enclosed volumes in the synchronous hydraulic cylinder. The hydraulic oscillator should always be operated in the resonant or natural frequency. Energy losses due to damping and friction are compensated by increasing the pressure, for example, at the maximum pressure at the point of reversal. The associated increase in volume is compensated for again after half a wavelength (π), that is, at zero pressure at the point of reversal. The stroke Sm ₁ , Sm ₂ (see. Fig. 1 ) of the two masses 12, 16 is detected via displacement sensors 30, 32. The control of the servo valve 26 via a control and / or regulating device 28. The control and / or regulating device varies the predetermined (computational) frequency f in small steps (+/-), up to the sum of the two strokes Sm ₁ and Sm ₂ or the two cylinder pressures a maximum is detected, for example, the travel and the travel time of the servo valve 26 are kept constant. This automatically determines the exact resonance frequency.

If the exact resonance frequency is determined by the control and / or regulating device 28, the stroke is defined by the volume preferably supplied at the reversal point. From the control and / or regulating device 28, the amount is set according to the Hubsollwertvorgabe s. The variation of the natural frequency takes place by switching on or off of equal volumes V _R and V _L on both sides of the piston (four-way valve). So can gradually the Shaking frequency can be adjusted. Alternatively, the volumes can be varied continuously by parallel movable hydraulic cylinders.

LIST OF REFERENCE NUMBERS

10

shaking

12

roller

14

roll axis

16

to ground

18

drive means

20

Cylinder / piston unit

22

piston

24

cylinder

26

servo valve

28

Control and / or regulating device

30

displacement sensor

32

displacement sensor

34

adjusting spring

36

adjusting spring

f

frequency setting

m ₁

Mass of the roller

m ₂

Mass of the countermass

p _L

Pressure curve, left

p _R

Pressure curve, right

R

servo valve

s

Hubsollwertvorgabe

S _m1

Stroke of the roller [graphic]

S _m2

Hub of the countermass [grapisch]

t

Time

V _L

Volume, left

V _L1

Additional volume, left

V _R

Volume, right

V _R1

Additional volume, right

W

way valve

Claims (14)

1. Shaking device (10) for moving a roll (12) of a machine for producing and/or treating a fibrous web back and forth along an axis (14) of the roll (12), in which the roll (12) is coupled resiliently to a counter-mass (16) in order to form an oscillating system, and drive means (18) are provided in order to drive the oscillating system comprising the roll (12) and the counter-mass (16) at the resonant frequency of the said system,
   characterized in that
   a hydraulic cylinder/piston unit (20) is provided, which is aligned with the roll axis (14) and of which the piston (22) is coupled to the roll (12), and of which the cylinder (24) is mounted such that it can move along the roll axis (14) in order to form the oscillating counter-mass (16), the roll (12) being resiliently coupled to the counter-mass (16) comprising the cylinder (24) via the enclosed volumes (V_L, V_R) provided on the two sides of the piston (22) of the in particular synchronous cylinder/piston unit (20).
2. Shaking device (10) according to Claim 1,
   characterized in that
   the cylinder (24) of the cylinder/piston unit (20) comprises a casing increasing the mass, in particular a concrete casing.
3. Shaking device (10) according to Claim 1 or 2,
   characterized in that
   the drive means (18) comprise means for the cyclic supply of pressure to the cylinder/piston unit (20).
4. Shaking device (10) according to Claim 3,
   characterized in that
   the drive means (18) comprise a servo valve (26), in particular for the cyclic supply of pressure to the cylinder/piston unit (20).
5. Shaking device (10) according to one of the preceding claims,
   characterized in that
   the cylinder/piston unit (20) can be acted on via the drive means (18) in such a way that energy losses caused by damping and/or friction are compensated for again by means of a corresponding increase in pressure, in particular at the pressure maximum at the point of reversal.
6. Shaking device (10) according to Claim 4,
   characterized in that
   the drive means (18) comprise an open-loop and/or closed-loop control device (28), in particular for driving the servo valve.
7. Shaking device (10) according to one of the preceding claims,
   characterized in that
   the drive means (18) comprise displacement sensors (30, 32) for measuring the displacement of the roll (12) and/or the displacement of the counter-mass (16).
8. Shaking device (10) according to Claim 6,
   characterized in that
   the open-loop and/or closed-loop control device (28) provided in particular for driving the servo valve (26) is designed in such a way that, in order to determine the resonant frequency of the oscillating system automatically, the excitation frequency with which the oscillating system is acted on is varied upwards and/or downwards in defined steps, starting from a predefinable frequency (f), until the sum of the displacements of the roll (12) and of the counter-mass (16) has reached a maximum.
9. Shaking device (10) according to Claim 8,
   characterized in that
   the resonance frequency of the oscillating system can be checked for changes continuously or at time intervals by means of an extremely minimal variation (+/-) of the predefinable frequency (f) and therefore an associated overall displacement change, and in that the predefined frequency (f) can be matched adaptively to the changing conditions, such as temperature or frictional conditions, for example.
10. Shaking device (10) according to Claim 8 or 9,
    characterized in that
    the open-loop and/or closed-loop control device (28) is designed in such a way that, during the variation of the excitation frequency, the actuating travel and the actuating time of the servo valve (26) are kept constant.
11. Shaking device (10) according to Claim 8, 9 or 10,
    characterized in that
    the open-loop and/or closed-loop control device (28) is designed in such a way that, after the resonant frequency of the oscillating system has been determined, the displacement of the counter-mass (16) is defined by the volume preferably fed in at the point of reversal of the cylinder/piston unit (20).
12. Shaking device (10) according to Claim 11,
    characterized in that
    the open-loop and/or closed-loop control device (28) is designed in such a way that the cylinder/piston unit (20) is fed with a volume corresponding to a respective predefined displacement set point (s).
13. Shaking device (10) according to one of Claims 6 or 8 to 12,
    characterized in that
    the open-loop and/or closed-loop control device (28) is designed in such a way that the resonant frequency of the oscillating system can be varied, by connecting and disconnecting equal volumes (V_L1, V_R1) to and from the two sides of the piston of the cylinder/piston unit (20), in order to set the shake frequency.
14. Shaking device (10) according to one of Claims 1 to 12,
    characterized in that
    the volumes on the two sides of the piston of the cylinder/piston unit (20) can be varied continuously via hydraulic cylinders that can be moved in parallel.

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