FI79571C - FOERFARANDE FOER PRESSBEHANDLING AV MATERIALBANOR, BOEJNINGSREGLERAD VALS OCH I SAMBAND MED DENNA ANVAEND VENTILANORDNING. - Google Patents

Description

The present invention relates to a method for compressing material webs such as paper or board through a compression zone formed by a compression element, such as a compression roll and / or a compression shoe, and in which the profile transverse to the direction of movement of the compression roll or shoe casing or similar track is controlled by a series of hydraulic elements loaded with hydraulically adjustable pressures.

The invention further relates to a deflection-controlled tk roll for use in a paper or board machine or finishing apparatus, comprising a stationary central shaft, a roll shell arranged to rotate around it, intended to form a compression zone with the counter-element and to which the central shaft is arranged with a plurality of load elements. the elements comprise a reading shoe having a sliding surface against the inner surface of the roller flange 25 and a load piston or the like operating in a load cylinder to which an adjustable pressure of the ER bellows medium can be applied.

The invention also relates to an electrically controlled valve device for use in the method of the invention and in the tk roll.

Various capacity-adjusted and compensated paper machine rolls are known, which are later commonly referred to as tk-rolls. Tk rolls are commonly used in paper machines or paper finishing machines as press rolls and calender rolls. The structure of the known tk rolls is generally such that they have a stationary central axis and a jacket rotating around it. Between the central shaft and the casing there are a series of 2 79571 1 hydraulic piston-loaded sliding shoes which can be pressed onto the inner surface of the roll casing, by means of which the roll casing and the compression pressure profile of the tk roll with its counter roll are adjusted in the tk roll axial direction. With regard to the details of the structure of the Tk rolls, reference is made as 5 examples to the applicant's FI patent applications No. 880515 and 881974.

With regard to the method for adjusting the compression profile of a deflection-compensated roll, reference is made to the applicant's FI patent application No. 870774 (cf. U.S. Pat. No. 085,358).

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Hydraulic and control technology has previously been used for profile adjustment of Tk rollers, so that the sliding shoes are arranged in several blocks containing e.g. 6-8 shoes, to each block of which a separate hydraulic pipe is introduced, to which the pressure of the medium to be fed is separately adjusted. The number of such blocks and pressure control areas can be at most about 6-8, because for each of about 50 different load shoes it is practically impossible to arrange a separate pressure pipe inside the roll and lead it there.

20 It could be considered possible to fit, for example, a remotely adjustable pressure relief valve from the outside in connection with each hydraulic load element inside the roll. However, such an arrangement using known valves would become practically unfeasible, not least because valves with mechanical moving parts cannot be made sufficiently reliable in practice, as a malfunction or damage of any valve would cause the entire roll to fail, leading to long downtimes on paper machines.

By using the above-mentioned 6-8 pressure control blocks, it is generally not possible to adjust the deflection profile of the roll shell as precisely as would be desirable. On the other hand, the limited number of pressure ranges leads to difficulty or complexity of the deflection control system and its stability and other control problems.

35 For the ER (ER Electro Rheological) phenomenon utilized in the present invention and its previously known applications, reference is made to U.S. Patent 2,417,850 and Machine Design / January 21, 1988, pp.42-46:

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1 Duclos, Acker, Carlson; "Fluids That Thicken Electrically." With regard to valve structures utilizing ER phenomena, reference is made to SU Patents Nos. 673793 and 885602.

3 79571 5 The object of the present invention is to develop a new method for the compression treatment of material paths, a new profile-adjusted tk roll and a new valve device, by means of which the problems discussed above can be largely avoided.

The object of the invention is to provide such a profile-adjusted tk roll, such as a press roll or a calender roll, in which a sufficiently large number of pressure control blocks can be used so that the pressure profile of the tk roll jacket and the nip formed by it can be controlled with sufficient accuracy.

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It is a further object of the invention to provide a profile-controlled tk roll and a valve device used in connection therewith in which the structures are made simple and reliable so that the tk roll does not cause downtime to the operation of the paper machine or paper finishing tray.

It is a further object of the present invention to provide a method, a tk roll and a valve device used therefor, which is preferably connectable to a paper machine control system, including a closed control system, in which the properties and tread profile of the web passed through the nip formed by the tk roll are measured and measured. adjusting the compression pressure profile of the nip formed by the tk roll.

Although the invention is described above and below with reference mainly to tk rolls, it is to be understood that the method and valve devices according to the invention can also be used with various so-called in connection with long nip pressing devices comprising either a compression zone formed by a counter roll and a long nip shoe member or a compression zone formed by two long nip shoe members, the transverse compression pressure profile of which is adjusted using the method according to the invention and / or valve devices according to the invention.

* 79571 1 In order to achieve the above and later objects, the method according to the invention is mainly characterized in that the pressures of the pressure gap applied to the hydraulic elements are controlled by ER-Electro Rheological pressure-5 pressure reducing .

The profile-controlled roll according to the invention, in turn, is characterized in that a medium pressure is applied to each load cylinder or cylinder group via a pressure relief valve based on the ER phenomenon, ER = Electro Rheological, that the medium is fed to different load elements via the same or the same ER liquid, preferably ER oil, the viscosity of which can be changed by means of changes in the electric field and that said ER valves are arranged outside the roll to be controlled by a series of electrical voltages.

The valve according to the invention, in turn, is mainly characterized in that the valve device is static in structure comprising at least two electrically isolated opposite electrodes spaced apart by a small electrode gap, said electrode gap limiting the flow channel of the valve connected on one side of the valve on the outlet side of the valve, and that said electrodes are connected to a controllable direct current source by which the pressure drop of the ER liquid passed through the flow channel between the valve electrodes can be varied by influencing the viscosity of said ER liquid by an electric field between the electrodes.

According to the invention, when using ER valves to control the load pressures applied to the load pistons of the tk roll reading shoe and ER fluid as the load medium, even each hydraulic load element can be provided with an electrically controlled ER valve, thus simplifying profile adjustment and simplifying control devices.

The structure of the tk roll according to the invention is preferably such that the tk roll has one common load medium inlet pipe, of which an ER valve is placed in the flow channel leading to each load element of Eris, and a recyclable special ER fluid is used as the hydraulic fluid. Each ER valve is separately connected to a control unit which electrically regulates the pressure drop of the valve and thus the load locally applied to the roll shell by the load-5 element. The control unit can be controlled on the basis of the measurement results of the properties of the web passing through the nip formed by the tk roll by utilizing a closed control system.

Thanks to the invention, the load shoes of the tk roll can be connected together in different ways, whereby the load width and position can be varied in order to achieve optimal profile adjustment.

It is known that temperature causes changes in the viscosity of ER fluids, which, however, can be advantageously compensated in the invention by adjusting the basic settings of the electrical voltage controlling the EF valves.

Since the valves used in the tk roll according to the invention do not require any moving parts in the valves used for pressure control of the load elements and since only one common pressure pipe needs to be introduced into the device, a fairly simple structure is obtained which is available so that the tk roll according to the invention has fewer malfunction and, in addition, provides faster, more accurate and more versatile profile adjustment of the press nip or calender nip.

The invention will now be described in detail with reference to some embodiments of the invention shown in the figures of the accompanying drawing, to which the inventions are not limited.

30

Figure 1 shows the method according to the invention and the related environmental devices schematically and partly in block diagram form.

Figure 2A shows a central axial reduction of a 35 roll according to the invention.

Figure 2B shows a vertical section A-A in Figure 2A.

6,79571 1 Figure 3A schematically shows the so-called ER vent tulle as a central cut.

Figure 3B shows a section B-B in Figure 3A.

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Figures 4A, 4B, 4C, 4D, 4E and 4F show, in a manner similar to Figure 3B, some alternative embodiments of the ER valve used in the invention. Figures 4A-4F are at the same time cross-sections along the line C-C marked in Figure 2A.

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Figure 5 shows a typical characteristic of a valve according to the invention.

Figure 1 illustrates the operating environment of the invention, related peripherals and a preferred embodiment of the invention.

Figure 1 shows a nip N formed between the rollers 10 and 30, which is, for example, a dewatering nip of a press part of a paper machine or a calendering nip of a calendar. The Tk roll 10 comprises a statonal central shaft 11 attached to its shaft journals 11a and 11b by load bases 34a, 34b which are loaded by hydraulic cylinders 35a and 35b to provide a base load of the nip N and / or to close or open the nip N. The rotating roller shoe 12 is mounted on a fixed shaft 11 as is known per se at both ends or is supported and supported only by the sliding shoes 16. The counter roll 30 is preferably a roll fixedly mounted on its shaft journal 30a and 30b.

The Tk roll 10 is an electrically controlled sheath profile-adjusted tk roll according to the invention, which has a large number of e.g. about 50 adjacent sliding shoes 16, which are loaded with adjustable hydraulic pressures in the cylinders 14 in the cylinders 14.

The system for controlling and managing the properties of the nip N shown in Fig. 1 and the paper or cardboard web passing through it (Fig. 2B) comprises a microcomputer unit 40 having e.g. zone pressure control and setpoint unit, system locks and I / O cards. The microdata machine unit 40 is controlled on the one hand by the user station 44 and on the other hand by the control table 41 via the connections 42,45. In addition, the parameters of the nip N are fed to the microcomputer unit 40 from the block 45 together via 46. The nip parameters are controlled by a unit 43 which includes a transverse web ii? 79571 1-direction property distribution measurement block 43, together via 44.

The microcomputer unit 40 controls via the connections 47 the voltage and pressure setting unit 31 of the roller 10 control-5, which receives its electricity for transmission 37a from the power supply 36. The unit 31 provides the load pressures of the load cylinders 35a and 35b, which are directed to the load cylinders 35a and 35b via In addition, the unit 31 provides the tk roll 10 with a series of control voltages U ^ ... U ^, (N = number of load shoes 16 10), which are conducted via a multi-pole cable 35 and a coupling unit 33 via a cable 37 placed in the space 13 between the roll shell 12 and the central shaft 11. From the cable 37, taps 36 (Fig. 2B) are taken for the electrically controlled ER pressure relief valves 20 used in the invention, which also have N pieces, i.e. one for each load-15 element.

Through the ER valves 20, an adjustable pressure p £ is applied to the cylinder 14 of the piston 15 of each element. The operating principles and different design variations of the ER valves 20 will be described in more detail later. In this connection, it should be noted at the outset that the ER valves (ER = Electro Rheological) 20 are static valves without moving parts controlled by electrical voltages Uj ... U ^, through which the viscosity of the special ER pressure medium passing through the direct voltage Uj. .11 ^ through 25 electric fields E in its area of influence.

Figure 1 shows, as block 50, devices for effecting the circulation of the ER bellows medium inside the tk roll 10. Fig. 1 shows an ER bellows medium inlet pipe 48 through which the medium inlet flow F is led to the bore 18 shown in Figs. 2A and 2B.

In addition, Fig. 1 shows an ER medium riser 39 connected to the outlet pipe 18a shown in Figs. 2A and 2B, through which the ER medium return flow F is taken to the unit 50. The unit 50 includes ER pressure medium pumps, filters and, if necessary, other equipment, such as cooling or heating equipment, to keep the temperature level of the ER pressure medium constant or in a certain range. Unit 50 may also include devices for measuring the temperature of the pressure medium 8 79571 1, on the basis of which the basic setting of the voltages U ^ ... UN is controlled. This operation is illustrated in Figure 1 by compound 51.

According to Figures 2A and 2B, the central shaft 11 of the tk roll 10 has a central bore 18 with a tube 18a inside. The pipe 18a and 18, the space defined by the bore 19 through the unit 50 is passed into the cylinder spaces of the pistons 15 14 ER valves 20 through the arrow direction of the pressure medium, in this case, specific additives with ER oil pressure p ^ through the bores 17. The flows of ER oil lubricating the sliding surface 16a of the sliding shoes 16 are led from the cylinder space 15 through the bores 15a 10 in the load pistons 15. For details of the construction of the sliding shoes 16 and the load cylinders and pistons, reference is made as examples to the applicant's FI patent applications Nos. 880515 and 881974. From the space 13 between the roll shell 12 and the central shaft 11, lubricating and pressure gaps are collected. and from there again to recycling.

The following are used as adjustable valves 20 (N pcs.) With electric voltages U ^ ... UN: the so-called ER valves based on the ER phenomenon. ER fluids undergo changes in viscosity when subjected to an electric field E. As ER fluids, e.g., hydraulic oil-based suspensions with the addition of certain additives such as starch, silica gel and / or certain polymers are used. ER liquids consist of a finely divided suspension in which the particle size of the particles is generally between 1 and 10. In addition, surfactants can be used in the ER fluids, if necessary, to promote the uniformity of the suspension.

The electric fields used in connection with ER fluids and the invention are typically of the order of 1 ... 4 kV / mm. Thus, ER liquids are known which have a low electrical conductivity and thus also a low power consumption, so that even the high control voltages used are not dangerous.

When an electric field is applied to ER fluids, their viscosity increases as the electric field strength E increases substantially linearly over a certain field strength range. This is based on the fact that the particles of the ER fluid additive are charged so that they have a positive and a negative side and thus the opposite polarity of the particles.

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When the sides having 9 79571 1 are attracted to each other, the particles chain in an electric field in a manner similar to ferromagnetic particles in a magnetic field. Said chaining causes an increase in viscosity.

5

In the invention, the ER phenomenon has been realized to be applied to the otherwise problematic pressure control of the load pistons of the tk rolls by utilizing the static ER valves 20 ^ ... 20 ^ according to the invention, which are preferably in each pressure pipe 17 of the tk roll 10. The ER phenomenon is sufficiently sufficient. fast because the viscosity of the ER fluid responds to changes in the electric field E in milliseconds. When using ER valves 20 ^ ... 20 ^, the electrical power consumption remains quite low when the ER liquid and its particulate additive or additives are appropriately selected.

15 The characteristic curve of a typical ER valve, the bellows loss AP - electric field E is shown in Fig. 5. By selecting the additives of the ER liquid and changing their concentration, the steepness of the characteristic curve of Fig. 5 can be changed and varied between e.g.

Figures 3A and 3B show a structural example of an ER pressure relief valve 20 used in the invention. A flow of ER liquid is arranged to flow through the valve channel 25, the pressure drop Δρ of which is regulated. Said flow channel 25 is delimited by opposite planar electrodes 22a and 22b, the constant spacing of which is denoted by D.

Electrodes 22a and 22b, which are of electrically conductive material, are attached to the insulating body 26 and are electrically insulated from each other. The electrodes 22a and 22b are locked in place by means 27, through which contacts 38a and 38b are passed to the electrodes 22a and 22b. The second electrode 22a is connected by a contact 38a and an electric line 30 27 to a voltage source 36 whose voltage U is adjustable. The counter electrode 22b is connected to the ground via the contact 38b and the line 37G as well as the negative terminal of the voltage source 36.

Between the electrodes 22a and 22b, an electric field of magnitude E = U / D is generated in the valve channel 25 by the action of the DC voltage. By adjusting the voltage U and thereby the strength of the electric field E, the viscosity of the ER liquid in the channel 25 and thus the pressure drop of the flow A p = Pj ~ P2 Pa ^ as ^ ^ predictive valve ^^^ - ^ s8 ^ 20 can be influenced.

The valve 20 shown in Figures 3A and 3E is characterized by static 5, i.e. it has no moving parts at all, so the valve 20 is very reliable and simple in construction.

Figures 4A-4F show some other examples of ER valves used in the invention. As shown in Figure 4A, the valve 20A has two opposing substantially semicircular conductive electrodes 22a, 22b with a narrow flow passage 25A therebetween. The electrodes 22a and 22b are attached to each other by insulating pieces 23 and dovetail joints 24. The electrodes 22a, 22b and insulating pieces 23 form a cylindrical structure 21 which is placed e.g.

15 inside the insulating sleeve into the bore 17.

The ER valve 2QB shown in Fig. 4B comprises four electrodes 22a, 22b, of which the electrodes 22a are connected to the positive voltage terminal and the electrodes 22b to the negative terminal. A cross-ribbed flow channel 25B is formed between the electrodes 22a and 22b. The electrodes 22a and 22b are attached to each other by insulating pieces 23 and dovetail joints 24: so as to form a cylindrical structure 21 with a cross | shaped flow channel 25B.

According to Fig. 4C, the ER valve 20C comprises two coaxial cylindrical electrodes 22a and 22b, of which the outer annular electrode 22a is connected to the negative terminal of the electric voltage and the inner cylindrical electrode 22b to the positive terminal. Between the circular cylinder surfaces of the electrodes 22a and 22b there is a uniform flow channel 30C connected at one end to the inlet side of the valve 20c and at the other end to the outlet side of the valve 20c.

The structure shown in Fig. 4D is otherwise similar to that shown in Fig. 4C except that the outer electrode 22a has a square opening with a square inner electrode 22b inside so that a square muted flow channel 24D remains between said electrodes.

Fig. 79571 Fig. 4Ε shows a modification of the ER valve according to Fig. 4A in which a flow channel 25E with a fractured cross-section is formed between the opposing electrodes 22a and 22b.

Fig. 4F shows a modification of the ER valves shown in Figs. 4A and 4E in which a flow channel 25F in the form of a rectangular broken line is formed between the opposing electrodes 22a and 22b. In Figures 4E and 4F, a larger cross-section of the flow channel is provided with a smaller electrode gap D, if necessary, which allows even lower electrical voltages Up..UN to be used to control the valves. Typically, the electrode gap D of the valves is in the range D 0.2 ... 5 mm, preferably D = 0.5 ... 2 mm. The voltages U ^ ... UN used in this case are usually in the range 1 ... 5 kV.

The valve 20; 20A-20F according to the invention can be made negative in the flow direction. By increasing the length of the valve, a certain pressure drop A p can be achieved with a lower control voltage Uj ... U ^ or a larger electrode gap D. Relatively small electrode spacings D can be used partly because ER fluids are generally quite good at electrical insulation.

It has been stated above that DC control voltages Up..U ^ can be used with the control voltage of the ER valves 20 ^ ... 20 ^, which affect the strength E of the electric field prevailing in the reference channel 25 of the ER valve 20 ^ 20.

25 It is not necessary to use a level-adjustable DC voltage to control the ER valves 20 ^ ... 20 ^. A preferred way of controlling the ER valves 20 and the tk roll 10 according to the invention is to use pulsed DC control signals U ^ ... U ^. The use of pulsed DC signals 30 is also advantageous in that the control of the tk roll 10 can be connected more simply to the control of modern digital control devices. When using the pulsed control signals U ^ ... U ^, a control method in which the length and / or height of the DC control pulse is constant but the frequency of the pulse-35 (number of pulses per unit time) is preferably adjusted and in this way the electric field strength can be affected the capacitance generated by the valve 20 acts in a way as an electrical integrator.

12 79571 Ί Control at voltages υ ^ ... υ ^ can of course also be used for pulse height and / or pulse width modulus. Regarding the suitability of using pulsed DC signals to control the ER effect, reference is made to the following journal article: Stevens, Sproston, Stanway: 5 "Influence of Pulsed D. C. Input Signals on Electrorheological Fluids;" Univ of Liverpool, Dep of Mechanical Engineering, Liverpool, Journal of Electrostatics, July 1985 pp. 181-191.

Although the invention has been described above with reference to application examples 10 in which each tk roll compression element is provided with its own ER valve 20, it should be noted that the invention also encompasses applications in which the ER pressure medium is applied to two or in some special cases several load elements. through the same ER valve 20. It should be emphasized, however, that the most preferred embodiment of the invention is one in which the different load elements of the lime are provided with their own separate ER valve.

The following claims set forth within the scope of the inventive idea defined by the various details of the invention may vary and differ from those set forth above by way of example only.

25 30

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Claims (17)

A method for compression treatment of webs of material such as paper or board webs (W), wherein the web (W) to be treated is passed through two compression zones formed by two opposing compression elements, such as a compression roll (10,30) and / or a compression shoe, and wherein the compression roll (10) or -the profile transverse to the direction of movement of the shoe shell (12) or the corresponding track (W) is controlled by a series (N) of hydraulic elements loaded with adjustable pressures (Pj) of the hydraulic medium »characterized in that the pressures of the pressure medium (P2) applied to the hydraulic elements is controlled by pressure relief valves (20 ^ ... 20Ν) based on the ER effect, KR = Electro Rheological, which are controlled by a series of electrical signals (U ^ ... UN) from outside the press roll or the corresponding press shoe. 15 1 Claims A method according to claim 1, applied to deflection-controlled tk rolls (10) using a stationary central shaft (12) and a rotating cylindrical shell (12) arranged to form a compression zone 20 with the counter roll (30) or shoe element. (N) and in connection with the stationary central shaft (11) of which a plurality (N) of hydraulic loading elements are arranged, by means of which hydraulically adjustable forces press the sliding shoes (16) against the inner surface of the roll shell (12) and in which adjustable hydraulics are supplied to said loading elements. (p ^)> characterized in that the pressures (p ^) applied to the hydraulic load cell are controlled by pressure relief valves (20 ^ ... 20 ^) based on the ER phenomenon, the pressure drop (Δ P) of which is controlled from a voltage source outside the tk roll (10) ( 13) imported electricity with a set of 30 voltages (1 ^ ... uN). Method according to Claim 2, characterized in that each hydraulic load element is provided with its own static pressure relief valve 35 (20r..20N) based on the ER effect. »79571 Method according to one of Claims 1 to 3, characterized in that the ER liquid used as a pressure medium in the method is led to different load elements by a common pressure pipe (19) and said pressure medium is recirculated from the inner space (13) of the tk roll (10) by a common with an outlet pipe (18) which at the same time leads from the space (13) between the stationary central axis (11) and the jacket of the pressure medium tk roll (10) acting as a lubricant in the sliding shoes (16) back to the medium circulation (F -Fq) · Method according to one of Claims 1 to 4, characterized in that the method uses continuous DC signals with a voltage level of the control unit (31) as a series of control voltages (U ^ - .. υ ^) for the ER valves (20 ^ ... 20 ^). ). Method according to one of Claims 1 to 4, characterized in that pulsed DC signals are used to control the ER valves (20p..20 ^), the pulse height and / or length of which is constant and the DC pulse frequency is modulated and / or stored. the height and / or length of the pulses are modulated to control the pressure losses (Aβ) caused by the ER medium flow 20 of the ER valves (20 ^ ... 20). Method according to one of Claims 1 to 6, characterized; that the effect of the change in viscosity caused by changes in the temperature of the ER fluid, such as the ER oil, is compensated by adjusting the basic setting of the level and / or duration and / or frequency of the control voltages of the ER vent (25 ... 20 ^). Method according to one of Claims 1 to 7, characterized in that the method measures the properties 30 and the distribution of the properties in the transverse direction of the track (W), and on the basis of said measurement a series of control signals is generated to control the ER valves (20). ... 20 ^) sets of control voltages (U ^ ... U ^). 9. For use in paper or board machines or finishing machines. . A deflection-controlled tk roll (10) comprising a stationary central shaft (11), a roller flange (12) arranged to rotate around it, intended to form a compression zone (N) II 15 79571 ^ with the counter-element (30) and having a central shaft (11) a plurality of loading elements comprising a sliding shoe (16) having a sliding surface (16a) against the inner surface of the roller flange (12) and a loading piston (15) or the like acting on the loading cylinder member (14) to which the loading cylinders 5 (14) are adjustable pressure of the pressure medium (P2) »characterized in that a pressure of the medium is applied to each load cylinder (14) or group of cylinders via a pressure relief valve (20 ^ ... 20 ^) based on the ER phenomenon, ER = Electro Rheological, that a different load -the medium is introduced into the measuring elements via the same or the same inlet pipes (19) 10 so that the load medium is an ER liquid, preferably an ER oil, j whether the viscosity can be changed by changes in the electric field (E) and that said ER valves (20p..20N) are arranged outside the roll to be controlled by a series of electrical voltages (ϋ ^.,. υ ^). A tk roll according to claim 9, characterized in that inside the stationary central axis (11) of the tk roll (10) there is an axial bore (19) from which transverse radial bores (17) exit in each load cylinder (14), and that in each of the latter an electrically controlled ER valve (20 ^ ... 20 ^) is arranged in the bore (17). 20 A tk roll according to claim 10, characterized in that inside said axial bore (19) there is a tube (18) through which the return flow (F) of the ER pressure medium is taken outside the roll (10), which return flow is led to a stationary central axis (11). ) From the space (13) between the roller 25 and the roller blade (12), into which the ER pressure medium has passed mainly after the sliding surface (16a) of the sliding shoes (16) has folded. Electrically controlled valve device for use in a method according to one of Claims 1 to 8 and / or in a deflection-controlled tk roll (10) according to one of Claims 9 to 11, characterized in that the valve device (20) has a static structure comprising at least two electrically isolated opposite electrodes (22a, 22b) spaced apart by a small electrode gap (D), said electrode gap (D) defining a valve reference passage (25) connected on one side to the valve inlet side and on the other side to the valve outlet side, and that said electrodes 16 79571 1 (22a, 22b) is connected to an adjustable direct current source (36) by which the pressure drop (& p) of the ER liquid passed through the flow passage (25) between the electrodes (22a, 22b) of the valve (20) can be varied by acting on the electric field between the electrodes (22a, 22b). E) the viscosity of said ER liquid 5. Valve device according to Claim 12, characterized in that the valve device (20) comprises two substantially parallel plate-shaped electrodes (22a, 22b) arranged inside the insulating body (26) and connected by contacts (38a, 38b) to an electrical source (36). (Figures 3A and 3B). 13 79571 Valve device according to claim 12, characterized in that the valve device comprises a valve body with a substantially circular cross-section with two opposite electrodes (22a, 22b) delimiting either a planar (Fig. 4A) or dashed (Figs. 4E and 4F) flow channel (Figs. 4E and 4F) 25A, 25E, 25F). Valve device according to claim 12, characterized in that the valve device comprises four or more pairs of opposite electrodes (22a, 22b) connected alternately to the positive and negative poles of the electric source (36) and that said electrodes (22a, 22b) ) delimit a cross-sectional flow channel (25B) (Fig. 4B). 25 Valve device according to claim 12, characterized in that the valve device comprises two nested electrodes (22a, 22b) delimiting a circular, elliptical or polygonal flow channel (25C, 25D) (Figures 4C 30 and 4D). Valve device according to one of Claims 12 to 16, characterized in that the electrode gap (D) of the electrodes (22a, 22b) delimiting the flow channel (25) of the valve device is in the range D = 0.2 to 5 mm, preferably in the range D * 0, 5 ... 1.5 mm and that the valve device is dimensioned so that the level of its control voltage (υ ^.,. Υ ^) is adjustable in the range 1 kV ... 5 kV. Il 17 79571