WO2003062527A1

WO2003062527A1 - Apparatus and method in connection with a headbox of a paper machine or the like

Info

Publication number: WO2003062527A1
Application number: PCT/FI2002/001047
Authority: WO
Inventors: Samppa Salminen; Reijo Huuskonen; Hannu LEPOMÄKI; Erkki Ilmoniemi
Original assignee: Metso Paper Oy
Current assignee: Valmet Technologies Oy
Priority date: 2001-12-28
Filing date: 2002-12-19
Publication date: 2003-07-31
Anticipated expiration: 2004-06-28

Abstract

The invention relates to an apparatus and a method in connection with a headbox (100) of a paper machine of the like. The stock flow is controlled by means of a film matrix (10b) by feeding to the film matrix (10b) a voltage signal whose frequency and/or amplitude is regulated. By means of the film matrix (10b) turbulence is generated in the stock flow or by means of the film matrix (10b) vibration is generated in the stock flow, which vibration damps the pressure variations of the stock flow.

Description

APPARATUS AND METHOD IN CONNECTION WITH A HEADBOX OF A PAPER MACHINE OR THE LIKE

The invention relates to an apparatus and a method in connection with a headbox of a paper machine or the like.

A patent related to EMFi film technology is known from US 4,654,546. The arrangement according to the US publication is based on EMFi film technology, which is a variant developed from PVDF film. The film is a 0.05...0.3 mm thick elastic polypropylene-based piezofilm. A change, brought about by a force, in the thickness of the EMFi film generates a voltage proportional to the force. On the other hand, a change in the thickness of the film can be brought about by means of a voltage. This film can be freely moulded into various measuring tapes, plates, etc. Today, the film is being used especially in keyboards for terminals and in loudspeakers.

This application discloses a new way of controlling the stock flow in connection with a headbox of a paper machine by affecting the stock flow by means of a so- called film matrix, whereby, by means of a voltage introduced into the film matrix, a change in the volume of the stock flow is provided and a force is directed at the stock flow. The frequency and/or amplitude of vibration of the film matrix is changed by changing the voltage signal introduced into the film matrix and thus, through the vibration of said film matrix, the stock flow is controlled by generating, in an embodiment of the invention, turbulence in the stock flow or by generating, by means of the film matrix, vibration in the stock flow, which vibration extinguishes/damps an interfering signal, caused e.g. by a pump, in the stock flow. In connection with the headbox of a paper machine, different sensors can be used for producing measurement data and for controlling the headbox of the paper machine. It has been difficult to produce said measurement data with traditional sensor technology. This invention discloses a measurement based on film technology for controlling the headbox. This application further discloses the use of a film matrix also for controlling the degree of turbulence of the stock flow. Control of the degree of turbulence takes place by feeding a voltage signal into the films, the frequency/amplitude of which signal is regulated. Said control of the degree of turbulence can be done with a separate film matrix that performs turbulence con- trol and the control can be based on the use of a matrix that carries out a separate measurement or the same film matrix can serve both as a measurement matrix and as a matrix that controls the degree of turbulence.

A surface element matrix is formed out of the film in a desired area of the head- box flow surface. Areas suitable for use are, for example, the upper and lower surfaces of the slice channel and the surfaces of vanes in the slice channel. The spacing of the elements in the machine and cross directions is chosen as desired, e.g. 1 mm. A conductor for the electronics is provided from each element.

In order to create turbulence the EMFi surface elements are fed with a phased voltage signal, the frequency and amplitude of which can be changed and thus regulated. A change in the film thickness caused by voltage brings about a volume change in the space inside the film, which volume change further causes the liquid to be displaced and thus creates turbulence. The magnitude and generation of tur- bulence on each matrix element or matrix element group can be controlled by means of amplitude regulation and time phasing of successive film elements with respect to the measurement process.

The turbulence can be measured by measuring the voltage signals coming from the different elements of the film matrix and by forming a spectrum out of said signals e.g. relative to time and/or relative to amplitude and relative to the position of the matrix element and relative to time.

In the arrangement according to the invention the turbulence of a paper stock flow or the like can be measured in the headbox and after this it can be adjusted as desired e.g. in the area of the slice channel of the headbox by conducting a voltage to the matrix elements of the film matrix and by generating a force by means of them, which force is directed at the stock flow.

The damping of pressure variations occurring in the short circulation of a paper machine or the like to a level at which harmful basis weight variations do not occur has to be carried out passively, in most cases by means of an air cushion. Due to the lack of a suitable actuating means producing pressure variations it has not been possible to use active dampers.

The pressure variations are measured at a suitable location in the slice of the headbox with a regular pressure sensor or with a film like the one known by the trade name EMFI. The measurement signal is processed so that a voltage signal can be formed, with which voltage signal another film of the type mentioned above and located before the place of measurement in the process is controlled, which film generates pressure variation oppositely phased with respect to the existing (measured) pressure variation so that the pressure variation can be optimally minimized.

The pressure-measuring film may also be located before the headbox, in which case it can be attached, for example, to an inner wall of a pipe, most advantageously so that the film is annular or tubular. The length of the film in the longitudinal direction of the pipe must be shorter than Vi of the wavelength corresponding to the highest frequency desired to be damped. In addition, to guarantee a good damping result, it is also possible to use another pressure sensor disposed in the headbox. The measurement of the pressure variations can also be carried out by traditional pressure sensors only.

A film producing counter pressure can similarly be attached to the inner wall of a pipe, and it is advantageously annular or tubular in shape and size. The efficiency can be improved especially at low frequencies, if the counter pressure is formed by using several separate tubular film sections, in which case they are controlled so that the highest frequencies are compensated by one film element only, and, as the frequency becomes lower, more and more elements are used depending on the frequency. Several elements may also be used for damping high frequencies, when the voltage signals are appropriately phased.

By means of the arrangement according to the invention an advantageous damping system can be provided compared, for example, to air cushion arrangements. At the same time many disadvantages caused by the use of an air cushion can be avoided (overflow, surface measurement, contamination, etc.).

A surface element matrix is formed out of the film in a desired area/areas. Areas suitable for use are, for example, an equalization chamber or a slice channel of a headbox. The spacing of the elements in the machine and cross directions is chosen as desired, e.g. 1 mm. A conductor for the electronics is provided from each element.

One matrix produces measurement data on the changes in the amplitude of vibra- tion, the other generates a change of volume / a force component for damping the vibration.

In order to create a damping force the EMFi surface elements are fed with a phased voltage signal, the amplitude and/or frequency of which can be changed. A change in the film thickness caused by voltage brings about a volume change in the space inside the film, which volume change further causes the liquid to be displaced, and thus provides damping. The damping by each matrix element or matrix element group can be controlled by means of amplitude regulation and time phasing of successive film elements with respect to the measurement process.

The damping can be measured by measuring the voltage signals coming from the different elements of the film matrix and by forming a spectrum out of said signals e.g. relative to time and/or relative to amplitude and relative to the position of the matrix element and relative to time.

In the arrangement according to the invention the pressure variations of a stock flow or the like, caused, for example, by the pumping of stock and/or by the operation of a separating means such as a screen, can be measured in the headbox and/or in a pipe system and after this said pressure variations can be damped by conducting a voltage to the matrix elements of a film matrix and by generating a volume change / a force by means of them, which force is directed at the stock flow. The amplitude and phasing of the voltage provided has been provided based on the pressure amplitude measured. The direction of the force applied from the film matrix is opposite to the direction of propagation of pressure pulses. In such a case the force applied from the matrix extinguishes or damps the pressure vibration.

The film matrix advantageously comprises one or more films, and the film matrix may be of the width of the headbox.

A paper machine or the like refers to a paper, board and tissue machine and a chemical pulp dryer.

The apparatus and method according to the invention are characterized in what is presented in the claims. The invention will now be described with reference to some preferred embodiments shown in the figures of the accompanying drawings, to which embodiments the invention is, however, not intended to be solely confined.

Figure 1A shows an embodiment of the invention in which a separate measurement matrix is arranged in a slice channel of a headbox and a separate matrix controlling the degree of turbulence is arranged in an intermediate chamber of the headbox.

Figure IB illustrates the formation of matrices according to Figure 1 A.

Figure IC shows an embodiment of the invention in which a turbulence- generating film matrix is disposed in a slice cone of a headbox.

Figure ID is a sectional view along the line I-I in Figure IC.

Figure IE shows the operating principle of one matrix element of a film matrix when a force is applied to the film matrix.

Figure IF shows the operation of one matrix element of a film matrix when a voltage change is introduced into the film matrix.

Figure 2 shows an embodiment of the invention in which a separate measurement matrix is arranged in a slice channel of a headbox and in a stock inlet pipe system and a separate matrix controlling the damping is arranged in the stock inlet pipe system of the headbox.

Figure 3 A shows an electronics diagram of the measurement matrix related to the embodiment of Figures 1 A and IB and 2. Figure 3B shows an electronics diagram of the matrix controlling the flow according to the embodiment of Figures 1 A, IB and IC, ID and of Figure 2.

Figure 1A shows a headbox 100 of a paper machine or the like according to the invention, in which headbox film technology is applied in the measurement of the degree of turbulence of a stock flow (arrow Li) and in the regulation of the degree of turbulence of the stock flow. As shown in Figure 1A, the headbox 100 comprises an inlet header J_ls from which the stock is passed via tubes 1 la_1; lla₂... of a tube bank 11 to an intermediate chamber E and further from the intermediate chamber E via turbulence tubes 12aι, 12a₂... of a turbulence generator 12 to a slice channel 13 and from there further onto a forming wire Hj.

As shown in Figure 1A, the headbox 100 of the paper machine comprises in its connection film matrices 10a and 10b. The measuring film matrix 10a comprises matrix elements 10aι _{l s} 10aj ₂... 10a_{2 1}, 10a_{2 2}--- and the film matrix 10b controlling the degree of turbulence comprises matrix elements 10b] _s 10bι ₂... 10b₂ 1 , 10b_{2 2}.... The matrix elements 10aι i, 10a_{) 2}... 10a₂ ι, 10a₂ ... are disposed in the slice channel 13 of the headbox of the paper machine, on an upper wall 13aι or vanes nι,nι of the slice channel 13. In the embodiment of Figure 1A, IB the ma- trix elements 10aι i, 10aι ₂— 10a_{2 1}, 10a_{2 2}--- are located in the slice channel 13 in different width positions of the headbox and further in different length positions of the headbox seen in the machine direction. Correspondingly, the matrix elements 10bi ₁, 10bi ₂-.. 10b₂ ι, 10b_{2 2"}- located in the intermediate chamber E are located in different width positions of the headbox and further, seen in the ma- chine direction of the paper machine or the like, in different length positions. Measurement data is produced from the film matrix 10a via a line ti to a central processing unit 50, and the film matrix 10b located in the intermediate chamber E is controlled based on said measurement data by means of the central processing unit 50 via a line t₂, which film matrix creates a force/forces for regulating the degree of turbulence of the stock flow Li based on said measurement data. The film matrix 10a is observed so that any change in pressure/force caused by the stock of the headbox 100 and directed at each matrix element lOai i, lOai ₂...10a₂ 1, 10a_{2 2}.. of the film matrix - and the resultant change in voltage - are measured. Based on said change, the stock flow in the intermediate chamber E in the width position of said measuring matrix element or matrix element group lOai, 10a₂... 10aπ, 10aι ... 10a₂ ι, 10a₂2-.- of the headbox 100 is regulated by producing a change in the volume of the matrix element or matrix element group 10bι i, 10bι ₂... 10b2 1, 10b₂2... situated in the corresponding width position of the headbox, and thereby affecting the stock flow Li in the headbox 100.

Figure IB shows the film matrix 10a disposed on the upper wall 13a of the slice channel 13 of the headbox and the film matrix 10b used for controlling the degree of turbulence disposed in connection with the intermediate chamber E of the headbox 100. The slice channel 13 comprises on the upper wall 13aj the film matrix 10a comprising the matrix elements 10aι i, 10aι ₂— 10a ₁, 10a_{2 2}.-. Each ma- trix element lOai i, 10aι ₂... 10a2 i, 10a22--. of the film matrix 10a measures the state of turbulence of the stock flow Li at that particular point as changes in the state of pressure of said point. Said changes in the degree of turbulence of the stock flow thus manifest themselves as pressure changes observed by the matrix elements 10aι i, 10ai 2... 10a₂ 1. 10a_{2 2}-- of the film matrix 10a. Information on said changes in the state of each matrix element lOai ι, 10aι ₂— 10a₂ 1, 10a2₂— or matrix element group of the film matrix 10a is transmitted via the data transfer line ti to the central processing unit 50. As illustrated in the figure, the voltage data is passed from the central processing unit 50 to the film matrix 10b in the intermediate chamber E of the headbox 100, the function of which film matrix is to generate the desired changes in the degree of turbulence of the stock flow based on the measured pressure differences. Thus, from the film matrix 10a shown in Figure IB, the data on the pressure change is provided to the central processing unit 50, and, based on said data, the desired voltage is produced in the other film matrix 10b, in its different matrix elements 10bι ₁, 10bι ₂... in order to generate the desired degree of turbulence in the stock flow. Said measurement data is passed via the data transfer line ti to the central processing unit 50, from where, after said data has been processed, instruction data is provided as a voltage for each particular matrix element 10bι, lOb∑... 10bι i, 10b_{1 2}... 10b_{2 1}, 10b_{2 2}... of each force-producing film matrix 10b via the data transfer lines t .

Figure IC shows an embodiment of the invention in which a headbox 100 comprises an inlet header Ji , thereafter a tube bank 11 , an intermediate chamber E and after this, in the flow direction of the stock, a turbulence generator 12 and a slice channel 13. The slice channel has vanes m and n₂. Turbulence-generating matrix films 10b of the invention extending across the width of the headbox are disposed in the slice channel confined by the surfaces of an upper wall 13aj and a lower wall 13a₂ of the slice channel 13. Matrix films 10b extending across the width of the headbox are also disposed on the surfaces of the vanes ni and n₂. Control is passed from a central processing unit 50 via data transfer lines to the film matrices 10b for regulating the degree of turbulence of the stock flow Lj in the headbox 100.

In the embodiments of Figures 1A, IB and IC, ID the degree of turbulence of the stock flow can be regulated by regulating the phasing and/or amplitude of the voltage signal fed into the matrix elements of the film matrix 10b. A paper ma- chine or the like refers to a paper, board or tissue machine and a chemical pulp dryer.

Figure ID shows the apparatus of Figure IC taken along the sectional line I-I. The turbulence-generating film 10b extends across the entire width of the slice channel 13 of the headbox.

Figure IE illustrates measurement taking place by means of a film matrix. The matrix element 10aι of the film matrix 10a comprises a voltage line eι,e₂. When a force ΔF is directed at the film matrix, the film matrix is compressed causing a change in the electric charge ΔQ of the film, which can be seen as a voltage change ΔU across the film matrix i.e. between its upper and lower surfaces fi and f₂. The greater the force ΔF applied to the matrix element lOai, the greater the force of the measurable voltage change ΔQ in the matrix element between the surfaces fi and f₂ of the film matrix.

Figure IF illustrates the matrix element 10bι of the film matrix 10b in operation in which a voltage difference ΔU is generated between the surfaces fi and f₂ of the film matrix 10b, which voltage difference causes a change ΔS in the thickness of the matrix element 10bι of the film matrix 10b. The greater the voltage difference ΔU that is generated between the top and bottom surfaces fj and f₂ of the matrix element 10bι, the greater the change ΔS caused in the thickness of the film matrix.

Figure 2 shows a headbox 100 of a paper machine or the like according to the invention in which film technology is used in the measurement of the pressure variations of the stock flow and in the damping of the pressure variations of the stock flow. As shown in Figure IC, the headbox 100 comprises an inlet header Ji, from which the stock is passed via tubes l lai, l la₂... of a tube bank 11 to an intermediate chamber E and further from the intermediate chamber E via turbulence tubes 12aι, 12a₂... of a turbulence generator 12 to a slice channel 13 and from there further onto a forming wire Hi.

As shown in Figure 2, the headbox 100 of the paper machine comprises in its connection film matrices 10a and 10b. The film matrix 10a comprises matrix elements 10aι i, 10aι ₂... 10a₂ ι, 10a22--- and the film matrix 10b comprises matrix elements 10bι i, 10bι ₂... 10b₂ ι, 10b_{2 2}.... The matrix elements 10aj i, lOai ₂... 10a₂ ι, 10a_{2 2}--- are disposed in the slice channel 13 of the headbox of the paper machine and in the stock inlet pipe system 30, via which the stock is passed to the headbox 100. The matrix elements 10aι i, lOaj ₂— 10a_{2 1}, 10a_{2 2}... may be located in the slice channel 13 in different width positions of the headbox and further in different length positions of the headbox seen in the machine direction. They may also be in the intermediate chamber E of the headbox. The matrix elements lObi 1, 10bι ₂... 10b_{2 1}, 10b_{2 2}— which are located in different length positions in the stock inlet pipe system 30 on the upstream side of the measurement matrices 10a, when seen in the stock flow direction Li. Measurement data is provided from the film matrices 10a via a line ti to a central processing unit 50, and the film matrix 10b located in the pipe 30 is controlled based on said measurement data by means of the central processing unit 50 via a line t₂, which film matrix creates a force/forces through volume changes for damping the pressure variations of the stock flow. The film matrix 10a is observed so that any change in pressure/force caused by the stock and directed at each matrix element 10aι i, 10aι ₂...10a_{2 1}, 10a₂₂... of the film matrix - and the resultant change in voltage - are measured. Based on said change, the pressure variations in the stock flow Li are damped via the matrix element or matrix element group 10bι i, 10bi ₂... 10b₂ ι, 10b22-.-

Figure 2 shows a film matrix 10a disposed in the slice channel 13 of the headbox and in the pipe 30 and a film matrix 10b used for controlling the damping dis- posed in the tube 30. The film matrix 10a formed of the matrix elements 10aι i, 10ai 2... 10a2 i, 10a_{2 2}-.. Each matrix element 10aι i, 10aι — 10a₂ ι, 10a_{2 2}... of the film matrix 10a measures the pressure state of the stock flow at that particular point as changes in said state. Said changes in the pressure of the stock flow, caused by a pump and/or a separating means such as a screen, are transmitted di- rectly to the matrix elements of the film matrix as pressure changes, which are transmitted further by the matrix elements 10aι ₁, 10aι ₂..- 10a_{2 1}, 10a₂₂... of the film matrix 10a as changes in their voltage. Information on said changes in the state of each matrix element 10an, 10ai ₂... 10a_{2 1}, 10a_{2 2}... or matrix element group of the film matrix 10a is transmitted via the data transfer line ti to the cen- tral processing unit 50 and from the central processing unit 50 further, as illustrated in the figure, to the film matrix 10b in the stock inlet pipe 30 leading to the headbox 100, the function of which film matrix is to generate, based on the measured pressure differences, the desired damping in the pressure variations of the stock flow. Thus, from the film matrices 10a shown in Figure IC, the data on the pressure change is provided to the central processing unit 50, and, based on said data, the desired voltage is produced in the different matrix elements 10bι 1, lObi 2... of the film matrix 10b producing a force / a volume change, in order to generate the desired pressure damping in the stock flow. Said measurement data is passed via the data transfer line ti to the central processing unit 50, from where, after said measurement data has been processed, instruction data is provided as a voltage for each particular matrix element lObi, 10b₂... lObi i, lObi ₂... 10b₂ ι, 10b22--- or matrix element group of each force-producing film matrix 10b via the transfer lines t₂.

As shown in Figure 2, the matrix elements 10aι _{1 ;} 10aι ₂... 10a ι, 10a_{2 2}-.- of the measurement matrix 10a are disposed in the slice channel 13 in different length positions in the machine direction and in different width positions of the headbox relative to the width of the machine. Correspondingly, the other measuring film matrix 10a is disposed in the stock inlet pipe 30 so that it is located, as to the matrix elements, in different length positions of the stock inlet pipe 30 and, in addi- tion, circumferentially on the outer circumference of the pipe 30 so that the surface of the matrix elements is delimited, directly or via an intermediate part, by the stock flow L_\.

The matrix 10b damping the pressure variations is correspondingly disposed in the stock inlet pipe 30 ahead of the measuring matrices 10a, when seen in the stock flow direction Li, and as circumferential structures on the inner surface of the pipe 30.

Figure 3A illustrates the electronics diagram relating to the measuring film matrix 10a of the embodiment of Figures 1A and IB and 2. The film matrix 10a is also arranged in different width positions of the slice channel of the headbox 100 for producing voltage data from each matrix element 10aj, 10a₂... lOai i, 10a_t ... 10a₂ ι, 10a_{2 2}--- of the film matrix further via pre-amplifiers 14aι,14a2...14a₆ to a multiplexer 15, which transmits the signals further via a buffer- amplifier 16 to a data collecting means, such as the central processing unit 50. This way the voltage data can be collected from each matrix element 10aι i, 10aι ₂... 10a₂ 1, 10a22-.- and thus an amplitude spectrum as a function of time can be obtained, which ampli- tude spectrum correlates with the changes in the degree of turbulence or in the pressure variations occurring in the stock flow of the headbox. The measured change in the degree of turbulence or in the pressure variations correlates with the change in the pressure of the stock flow, which, in turn, corresponds to each measured change in the voltage of the matrix elements lOai _ls 10a] ₂... 10a₂ i, 10a2₂.... or matrix element groups of the film matrix. When the matrix elements lOai i, lOai ₂ of the film matrix 10a are located at different points in the headbox, a measuring field can be formed by means of the matrix elements 10aj, 10a₂... lOai 1, 10ai 2... 10a₂ ι, 10a22--- Correspondingly, the matrix elements lObi 1, 10b] 2— 1 Ob₂ 1 , 10b22-_"- of the film matrix 10b form a power input/state change field for regulating the degree of turbulence in the stock flow Li or for evening out of the pressure variations caused by pumps and/or a separating means such as a screen, when passing the stock flow to the headbox of the paper machine or the like .

Figure 3B illustrates the electronics diagram relating to the film matrix 10b that controls the flow according to the embodiment of Figures 1A, IB and IC, ID and 2. In Figure 1H the controlling of the stock flow Lj of the headbox 100, such as the controlling of the degree of turbulence and of the damping, is further affected by producing, based on the measurement, a certain voltage in the film matrix 10b controlling the flow and located in the intermediate chamber E or in the slice channel 13 of the headbox 50 or when evening out the pressure variations of the stock flow in the inlet pipe 30 leading to the headbox 100. This makes it possible to introduce a voltage of the desired magnitude from the central processing unit 50 into each matrix element 10b_u 10b₂... lObi ₁, 10bj ₂... 10b₂ 1 , 10b₂2-- of the film matrix 10b or into a separate group formed by them and located, for example, in the intermediate chamber or in the pipe 30. A power source 17 produces energy for a pulse generator 18, which generates pulses of the desired voltage for a control 19 of analog switches 19aι, 19a₂...19a₆ for producing a voltage of the desired magnitude for each matrix element 10bι 1, 10bι ₂... 10b₂ 1, 10b2₂--_" of the film matrix 10b via amplifiers 19aι,19aι ...l9a₆. Thus, by means of the voltage produced into each matrix element lObi, 10b2... lObi.i, lθbι.2... 10b₂ 1, 10b₂.2.... of the film matrix 10b, the matrix element in question can be made to expand and bring about a change of state/a force at said matrix element or group of matrix elements in the intermediate chamber E of the stock flow Li (embodiment of Figures 1A, IB) or in the slice channel 13 (embodiment of Figures IC, ID), or in which pipe 30 the pressure variations in the stock flow are damped by means of the film matrix 10b according to the embodiment of Figure 2.

Claims

1. An apparatus in connection with a headbox (100) of a paper machine or the like, characterized in that there is a film matrix (10b), by means of which a stock flow is controlled by feeding to the film matrix (10b) a voltage signal whose frequency and/or amplitude is regulated, and that by means of the film matrix (10b) turbulence is generated in the stock flow, or that by means of the film matrix (10b) vibration is generated in the stock flow, which vibration damps the pres- sure variations of the stock flow.

2. An apparatus in a headbox (100) of a paper machine or the like, characterized in that the headbox (100) comprises, in its connection, a film matrix (10b) with which a change is produced as a change in the volume of / as a force applied to a stock flow for regulating the degree of turbulence of the stock flow of the head- box in the headbox (100) by feeding to the film matrix (10b) a voltage signal whose frequency and/or amplitude is regulated.

3. An apparatus according to claim 1 or 2, characterized in that there is a measur- ing film matrix (10a) composed of matrix elements (10aπ, 10aι ₂... 10a_{2 1},

10a_{2 2"}--) based on the measurement result of which the frequency and/or amplitude of the voltage signal of the film matrix (10b) is regulated.

4. An apparatus according to claim 1 or 2, characterized in that there is a force- producing film matrix (10b) composed of matrix elements (lObj i, 10b] ₂...

10b_{2 1}, 10b_{2 2}....)-

5. An apparatus according to any one of the preceding claims, characterized in that the matrix elements (10aι i, 10aι ₂... 10a_{2 1} , 10a_{2 2}....; 10bι _I , 10bι ₂... 10b2 1, 10b_{2 2}....) of the film matrix are each arranged to operate separately or they form groups in order to produce or receive voltage data.

6. An apparatus according to any one of the preceding claims, characterized in that the film matrix (10a) is arranged to produce measurement data, preferably pressure change data as voltage data to a central processing unit (50) and that from the central processing unit (50) the voltage data is further provided for the force-generating film matrix (10b) for regulating the degree of turbulence of the stock flow.

7. An apparatus according to any one of the preceding claims, characterized in that the matrix elements of the film matrix (10a, 10b) function so that, when a voltage change is introduced into them, they expand or contract, and if a pressure change is directed at them, said pressure change can be measured as a voltage change of the matrix element.

8. An apparatus according to claim 3, characterized in that the film matrix (10a), comprising the matrix elements (10aι i, 10aι 2— 10a2 1, 10a_{2 2}-—)_> comprises in its connection a preamplifier (14), via which the signal data from each matrix element is transmitted to a multiplexer (15), which transmits the signal data further via a buffer- amplifier (16) to a data collector, such as a central process- ing unit (50).

9. An apparatus according to claim 4, characterized in that the film matrix (10b) used in regulating the degree of turbulence comprises the matrix elements (10bι ₁, 10bι ₂... 10b₂ ι, 10b₂2....) and that there is a power source (14), by means of which energy is produced with a pulse generator (18) producing pulses of the magnitude of the desired voltage to a control (19) of analog switches (19aι, 19a₂...) for producing a voltage of the desired magnitude in each matrix element (10bι 1, 10bι ₂... 10b₂ ι, 10b_{2 2}....) of the film matrix (10b), whereby, by means of the voltage provided, each matrix element or each group formed by them, can be made to expand and produce a force in the stock flow at said matrix element or group formed by the matrix elements.

10. An apparatus according to any one of the preceding claims, characterized in that the film matrix (10a) performing the measurement is disposed in a slice channel (13) of the headbox (100).

11. An apparatus according to the preceding claim, characterized in that the matrix elements (10aι i, 10ai 2... 10a ι, 10a_{2 2}..--; lOct _{l s} 10cι ₂... 10c₂ 1, 10c₂2- - .) of the film matrix (10a) are arranged in connection with the headbox (100) so that the matrix elements are located in different length positions of the head- box and in different width positions of it.

12. An apparatus according to claim 10 or 11, characterized in that the film matrix (10a) performing the measurement is disposed on a wall (13aι) of the slice channel (13) so that said film matrix is, directly or via an intermediate part, in contact with the stock flow (Li) in the slice channel.

13. An apparatus according to any one of the preceding claims, characterized in that the film matrix (10a) performing the measurement is disposed on the surface of a vane/vanes (nι,n₂) of the headbox (100).

14. An apparatus according to any one of the preceding claims, characterized in that the turbulence-regulating and force-generating film matrix (10b) is disposed before the film matrix (10a) performing the measurement, when seen in the flow direction (Li) of the stock flow.

15. An apparatus according to any one of the preceding claims, characterized in that the turbulence-regulating and volume change-/force- generating film matrix (10b) is disposed in an intermediate chamber (E) of the headbox (100) in front of a turbulence generator (12), when seen in the flow direction (Li).

16. An apparatus according to claim 1, characterized in that the turbulence- regulating film matrix (10b) is disposed in the slice channel (13) of the headbox of the paper machine.

17. An apparatus according to claim 16, characterized in that the turbulence- regulating film matrix (10b) is disposed on a wall (13aι ) of the slice channel (13) of the headbox or in a vane/vanes (nι,n₂) in the slice channel.

18. An apparatus according to any one of the preceding claims, characterized in that a phased voltage signal is passed into the turbulence-regulating matrix (10b), the amplitude and phasing of which signal can be regulated according to the requirements of the need for regulation each particular time.

19. An apparatus according to claim 1 in connection with the headbox (100) of a paper machine or the like, characterized in that the apparatus comprises a sensor or a sensor matrix by means of which pressure variations occurring in the stock flow (Li) of the paper machine or the like are measured and based on said measurement data the pressure variations of the stock flow are regulated/damped with the film matrix (10b) by feeding to the film matrix (10b) a voltage signal whose frequency and/or amplitude is regulated.

20. An apparatus according to claim 19, characterized in that the measuring sensor matrix comprises pressure sensors or a film matrix (10a) that comprises matrix elements (10aι i, 10aj ₂... 10a₂ 1, 10a_{2 2}-- based on the measurement result of which the frequency and/or amplitude of the voltage signal of the film matrix

(10b) is regulated.

21. An apparatus according to claim 19, characterized in that the film matrix (10b) producing a force/volume changes is composed of matrix elements (10bι ι, 10bι ₂... 10b₂ ι, 10b_{2 2}....).

22. An apparatus according to claim 20 or 21, characterized in that the matrix elements (lOai i, 10a, ₂- 10a_{2 )}, 10a_{2 2}....; lObi i, 10b_{1 2}... 10b_{2 1}, 10b_{2 2}....) of the film matrix (10a, 10b) are each arranged to operate separately or they form groups in order to produce or they form groups in order to produce or receive voltage data.

23. An apparatus according to claim 20 or 22, characterized in that the film matrix (10a) is arranged to produce measurement data, preferably pressure change data as voltage data to a central processing unit (50) and that from the central processing unit (50) the voltage data is further provided for the force- producing film matrix (10b) for damping the pressure variations of the stock flow.

24. An apparatus according to any one of the preceding claims 19 - 23, charac- terized in that the matrix elements of the film matrix (10a, 10b) function so that, when a voltage change is introduced into them, they expand or contract, and if a pressure change is directed at them, said pressure change can be measured as a voltage change of the matrix element.

25. An apparatus according to claim 19 or 20, characterized in that the film matrix (10a), comprising the matrix elements (10aι i, 10aι ₂... 10a₂ ι, 10a₂₂....), comprises in its connection a preamplifier (14), via which the signal data from each matrix element is transmitted to a multiplexer (15), which transmits the signal data further via a buffer-amplifier (16) to a data collector, such as a cen- tral processing unit (50).

26. An apparatus according to any one of the preceding claims 19, 21, 22 or 24, characterized in that the film matrix (10b), which comprises the matrix elements (10bι i, 10bi ₂... 10b2 i, 10b22---)j comprises in its connection a power source (14), by means of which energy is produced for a pulse generator (18) producing pulses of the magnitude of the desired voltage to a control (19) of analog switches (19aι, 19a₂...) for producing a voltage of the desired magnitude in each matrix element (lObi i, lObi ₂... 10b₂ ι, 10b2.2....) of the film matrix (10b), whereby, by means of the voltage provided, each matrix element or each group formed by them, can be made to expand or contract and produce a force in the stock flow at said matrix element or group formed by the matrix elements.

27. An apparatus according to any one of the preceding claims 20, 22, 23, 24, 25, characterized in that the film matrix (10a) performing the measurement is disposed in the headbox (100) and/or in a stock inlet pipe (30) of the headbox

(100).

28. An apparatus according to the preceding claim, characterized in that the matrix elements (10aι i, 10aι 2— 10a₂ ι, 10a_{2 2}....) of the film matrix (10a) are ar- ranged in connection with the headbox (100) so that the matrix elements are located in different length positions of the headbox and in different width positions of it.

29. An apparatus according to the preceding claim, characterized in that the film matrix (10a) performing the measurement is disposed as a circumferential structure in the stock inlet pipe (30).

30. An apparatus according to claim 20, 22, 23, 24, 25, 27, 28 or 29, characterized in that the film matrix (10a) performing the measurement is disposed on a wall (13a) of an equalization chamber (E) or of a slice channel (13) of the headbox (100) so that said film matrix is, directly or via an intermediate part, in connection with the stock flow (Li) in the slice channel (13) or in the equalization chamber (E).

31. An apparatus according to any one of the preceding claims 19, characterized in that the film matrix (10b) damping the pressure variations is disposed before the film matrix (10a) performing the measurement, when seen in the flow direction (Li) of the stock flow.

32. An apparatus according to any one of the preceding claims 19, 21, 22, 24, 26 or 31, characterized in that the film matrix (10b) damping the pressure variations and producing a change of volume / a force is disposed in the stock inlet pipe (30) leading to the headbox (100).

33. An apparatus according to any one of the preceding claims 19, 21, 22, 24, 26, 31 or 32, characterized in that a phased voltage signal is passed into the matrix

(10b) damping the pressure variations, the amplitude and phasing of which signal can be regulated according to the requirements of the need for regulation each particular time.

34. An apparatus according to any one of the preceding claims 19, 21 , 22, 24, 26, 31, 32 or 33, characterized in that the matrix elements (10bι i, 10b _{1 2}... 10b₂ i , 10b₂₂....) of the matrix (10b) damping the pressure variations are disposed on the walls of the inlet tube (30) so that they are, directly or via an intermediate part, in contact with the stock flow (Li) and that they are placed as circumferen- tial structures on the inner circumference of the pipe 30 in different length positions of the pipe.

35. A method in the damping of pressure variations of a headbox of a paper machine or the like, in which method an apparatus according to any one of claims 19 - 34 is used, characterized in that in the headbox (100) or in connection with it pressure variations occurring in a stock flow (Li) are measured and by means of said measurement data the pressure variations are regulated or damped with a film- like actuator (10b) by means of a voltage.