FI13408Y1 - Arrangement to measure the position of a top list in a head box of a fibre web machine - Google Patents

Abstract

1. Arrangement for measuring the position of a tip strip in the inlet box of a fiber web machine, which arrangement (10) comprises – a reference point (14) which can be arranged to follow the tip strip (12), – measuring devices (15) for determining the position of the reference point (14) from the outside of the inlet box (13), characterized in that – the measuring devices (15) include two sensors (19, 20) for determining the position of the reference point (14) in two dimensions, – each of the sensors (19, 20) is equipped with two attachment points (19.1, 19.2, 20.1, 20.2), of which – on their first attachment point (19.1, 20.1) the sensors (19, 20) are arranged to follow the reference point (14), – on their second attachment point (19.2, 20.2) the sensors (19, 20) arranged in connection with the fixed frame structure (49) of the inlet box (13), so that the distance (D) between the other attachment points (19.2, 20.2) is constant.

Description

ARRANGE THE TOP LIST STATION OF THE FIBER WOVEN MACHINE'S TANK BOX

TO MEASURE

The subject of the invention is an arrangement for measuring the position of the headboard of the end box of a fiber web machine, which arrangement includes - a reference point that can be adapted to follow the headboard, - measuring means for determining the position of the reference point from outside the endbox.

From the end box of the fiber web machine, the mass jet is fed from the opening between the upper lip and the lower lip to the wire part for web formation. The opening can be adjusted in different ways. The lip opening and lip gap of the tail box refers to the vertical and horizontal distance between the tip of the bottom lip of the tail box and the tip of the top lip arranged on the top lip. These quantities have a very large effect on the paper manufacturing process and the final properties of the paper. The lip gap adjusts where the mass jet hits the wire, and the thickness of the mass layer coming onto the wire is adjusted with the lip gap. The measurement should be as accurate as possible, so that the lip difference and lip gap entered into the flow calculations of the machine control would be truthful and would not cause problems in process control (e.g. the flow amounts would be 0 correct).

No. 25

S Well-known technology is represented by measuring the lip opening and the lip 2 of the tail box with two LVDT linear sensors. Because ho-

In the sub-area, both horizontal and vertical movement must be measured — — measuring with linear sensors is difficult. If

S 30 lip gap or lip gap is changed, so the change is in motion

N usually has an effect on another measured quantity as well, i.e. a change in the lip gap also changes the lip gap and vice versa. In addition, the articulation solution of the upper lip bar makes the vertical movement non-linear (curved). To compensate for this non-linearity, a separate, relatively difficult compensation calculation for machine control is usually required.

In addition, in many cases the LVDT sensors have to be supported relatively far from the tip of the lip. In this case, the measurement does not take into account the flexibility of the upper lip structure. This usually also has to be compensated by calculation.

The state of the art is also referred to the Finnish utility model FI 11377 U. Its problems are the expensive price and difficult adaptability to tail box structures.

The purpose of this invention is to create an arrangement for measuring the position of the headboard of the end box of a fiber tape machine, which is simple in its implementation and with which one arrangement can be used to measure the position of the headboard with regard to the various variables associated with it. The characteristic features of the arrangement according to the invention are presented in claim 1.

The arrangement includes two sensors adapted to follow the tip list to follow an adjustable reference point.

The sensors are arranged at an angle to each other and in such a way that they or their imaginary extensions intersect each other. Different-

S 25 specifically, one part of the sensors is adapted to the same

S to a reference point, which in particular is a reference point. On the opposite 2 end, the sensors are attached to the other part of the

E at a distance from each other, which distance is constant. In this way, the triangular geometry formed by the sensors can be measured

S 30 lip openings, i.e. between the upper lip (top lip) and the lower lip

N gaps and lip gap, i.e. the distance between the lips in machine direction.

With the arrangement according to the invention, it is possible to reliably measure, for example, the horizontal and/or vertical movement of the upper lip, i.e. the lip opening and the lip gap according to the horizontal and vertical displacement of the actual tip. In this case, separate, difficult and problematic compensation calculations are no longer needed. The measurement method also takes into account the elastics of the upper lip area, so separate compensation is not needed for that as well with the invention.

According to one form of application, the sensors belonging to the arrangement are adapted from one of their parts directly to the reference point, which is adapted to follow the top of the peak list. In this case, there is no need, for example, for motion transmitters, which bring precision to the measurement. In other words, the sensor means are adapted to determine the position of the reference point freely, i.e. without movement restrictions in two dimensions. The arrangement according to the invention can be installed in various tail boxes also as a retrofit. Other additional advantages achieved by the invention are evident from the explanatory part and the characteristic features from the accompanying protective claims.

The invention, which is not limited to the form of application presented below, is explained in more detail by referring to the accompanying figures, in which

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S 25 Figure 1 shows a principled example of a

A cross-section of S ko structures where arrangement 2 can be applied, looking at the tail box from the side

Exposed and without the arrangement according to the invention, — Figure 2 shows a principle view of an arrangement according to the invention, viewed from the side of the tail box : j >"

Figure 3 shows a principle view of the arrangement shown in Figure 2 in the machine direction, looking at the tail box from the side of the lip opening.

Figure 1 shows a principle example of the end box 13 of a fiber web machine in terms of its structures as a cross-section, viewed from the side of the end box 13. In Figure 1, the rear box 13 is depicted without the arrangement according to the invention. The rear box 13 can be implemented as is known from the state of the art. At least one manifold 26 is connected to the tailbox 13 to lead the mass flow to the tailbox 13. The manifold 26, with which the mass suspension flow is brought to the tailbox 13, can typically be, for example, a tubular mass suspension manifold that tapers in its flow direction.

The rear box 13 includes a turbulence generator 27 following the MD manifold 26 in the machine direction, which can also be of a type known from the state of the art. Turbulence generator 27 includes a set of flow pipes 28 for mass flow in the tail box 13 shown. The flow pipes 28 can be formed from the throttle pipes that are closer to the manifold 26 in the flow direction and from the expansion pipes that follow them in the flow direction. A step-like expansion in the direction of flow can form between the throttling pipes and the expansion pipes. Expansion pipes are used to form

S 25, in a known manner, is a cell with several adjacent

S-shaped extension tubes in overlapping rows. The position of the pipes 2 between the different rows can vary in a known manner depending on the machine

E in the direction of the cat.

S 30 follows the turbulence generator 27 in the stern box 13 as such

In a known manner, the lip channel 29. From the 5 lip openings 30 following the lip channel 29, the mass suspension to be banded is fed in a known way from the end box 13 to the wire part (not shown), where the band is formed.

The fixed frame structure 49 of the tail box 13 comprises the upper and lower frames 18, 33. Between the upper frame 18 and the lower frame 33, some of the functional parts of the tail box 13 are formed, such as, for example, the turbulence generator 27. The upper lip 17 is rotatably hinged to the upper frame 18. The upper and lower frame 18 , 33 remain in place when the upper lip 17 moves. In turn, the lower lip 37 is firmly fitted to the lower body 33. The upper lip 17 and the lower lip 37 delimit the lip channel 29.

A top strip 12 is arranged on the outside of the upper lip 17, which is rotatably attached to the upper frame 18 and can be moved in relation to it, in connection with the lip opening 30. The top strip 12 extends to the entire transverse CD length of the end box 13 of the lip opening 30.

The headboard 12 can be positioned using a set of actuators 34 arranged in the transverse direction of the end box 13 at a distance CD from each other, only one of which is shown in figure 1. The tip 12 is connected to the actuator 34 by, for example, an adjustment spindle (figure 3). In addition, the actuator 34 can also be used to shape the end strip 12, for example, to adjust the square weight profile.

N 25 from the upper lip 17 of the tail box 13 and therefore also arranged in it

The tip slat 12 can be moved to the upper lip 17 2 of the tail box 13 with a directed movement. The upper lip 17 of the tail box 13 can be

E articulated in the known way in the transverse direction of the machine — to the upper frame 13 of the tail box 18 from its joint point 36. Joint point

S 30 36 allows the upper lip 17 to be rotated with respect to the upper body 18. Reverse

N changes the distance and/or machine direction MD position between the tip 12 and the 5 lower lip 37 fixed to the lower frame 33. From the upper lip 17, it and the upper body can be turned

with an actuator 48 arranged between 18. Figures 1 and 2 show the flow direction of the mass flow and thus also the machine direction

MD with an arrow drawn below the tail box 13.

Figure 2 shows a principle view of the arrangement according to the invention viewed from the side of the end box 13, and Figure 3 shows the arrangement 10 viewed from the machine direction, viewed from the front of the end box 13, i.e. from the direction of the wire part. The arrangement 10 is intended for measuring the position of the top strip 12 fitted to the lip opening 30 of the end box 13 of the fiber web machine. Examples of the position can be mentioned the measurement of the previously mentioned lip gap and/or lip gap dimensions, where the position of the tip ledge 12, and even more generally the upper lip 17, relative to the lower lip 37, for example, is measured.

In its basic form, the arrangement 10 for measuring the position of the headboard 12 from outside the tail box 13 includes a reference point 14 that can be followed by the head board 12 and measuring instruments 15 to determine the reference point 14 and thus also the position of the head board 12 from outside the head box 13. When placed outside the tail box 13, the arrangement 10 can be easily installed in connection with the tail box 13, also as a retrofit, and thus the measurement can be quickly put into use.

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& 25 Reference point 14 can be formed in an application form mu-

S, for example, about a pin and even more specifically about a pivot pin. 2 It is easy to align the pin with respect to the tip 12. Reference-

E point 14 can be installed to be located in the transversal direction CD of the tail box 13, for example with the tip of the tip strip 12 at the same time

S 30 on the line. Reference point 14 aligned with the tip

The movement of N kilista 12 is found out as truthfully as possible. It always moves along the same g transverse line with the 12 tips of the tip list. The tip of the tip list 12 can be serrated, serrated or also beveled.

The measuring means 15 can be fitted to the fixed frame structure 49 of the tail box 13 (Figure 3) on the outside of the tail box 13. In this case, the measuring means 15 can be fitted, directly or indirectly, to the fixed frame structure 49 of the tail box 13, for example to the side wall 47 of the tail box 13. In this way, we can also speak of the side wall 47 of the tail box 13 frame and even more specifically, the immovable, i.e. fixed, upper frame 18.

The measuring instruments 15 include two sensors 19, 20. The sensors 19, 20 are adapted to the arrangement 10 for cooperation in order to determine the position of the reference point 14 two-dimensionally. Thus, the sensors 19, 20 can be said to be adapted to also form at least one sensor pair. The sensors 19, 20, i.e. the pair of sensors formed by them and the reference point 14, is at least on one side of the tail box 13.

Each of the sensors 19, 20 is equipped with two attachment points, more specifically the first attachment point 19.1, 20.1 and the second attachment point 19.2, 20.2.

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S 25 From its first attachment point 19.1, 20.1, sensors 19, 20 are

S adapted to follow the reference point 14. For this, the sensors 19, 20 are adapted from the first attachment point

The distance 19.1, 20.1 directly attached to the reference point 14. Thus — the sensors 19, 20 directly measure the movement of the reference point 14,

S 30 with which it can be converted into an electronic form of the tip list 12

N to recognize the movement and thus also to measure it. The attachment of the sensors 19, 20 to the reference point 14 thus takes place without, for example, any special motion transmitters.

In this case, the movement directed and measured by the reference point 14 and thus also the sensors 19, 20 is free and takes place unobstructed.

The movement of the reference point 14 with the tip of the tip list 12, i.e. following the tip of the tip list 12 always in the same transverse line, can be arranged to happen with the help of the support outside the tail box 13, which is arranged for the reference point 14.

From their second attachment point 19.2, 20.2, the sensors 19, 20 are adapted to the fixed frame structure 49 of the rear box 13. This is arranged so that the distance D between the other attachment points 19.2, 20.2 is constant, i.e. known. Thus, the sensors 19, 20 are also adapted to the triangular geometry. In this case, the length of one side of the triangle is always constant D, i.e. known, and the length of two sides, i.e. the sides formed by the sensors 19, 20, changes depending, for example, on what is being adjusted in relation to the lip opening at any given time.

For the sensors 19, 20, a first support 23 is fitted to the fixed frame structure 49 of the rear box 13, with which the second attachment points 19.2, 20.2 of the sensors 19, 20 are fitted or can be fitted to a horizontal arrangement. Thus, sensors 19, 20

S 25 can be said to be adapted from its second attachment points

O 19.2, 20.2 for the congruent machine-oriented MD level. 2

E In the presented form of application, the support 23 includes a horizontal beam — 24. The horizontal beam 24 is adapted to form a joint an-

S 30 for the 19, 20 stitches of the second joint points that are now formed

N to other anchorage points 19.2, 20.2. The horizontal beam 24 is fitted firmly and horizontally to the fixed frame structure 49 of the tail box 13. The fastening can be done, for example, with a vertical beam 21. It attaches, for example, from its lower part to the fixed frame structure 49 of the tail box 13, such as for example to the side wall 47. The perpendicular distance of the reference point 14 from the horizontal beam 24 can be for example 50 to 600 mm.

According to one form of application, the sensors 19, 20 are fitted from their second attachment point 19.2, 20.2 to the fixed frame structure 49 of the stern box 13, now more specifically to the support 23 and even more specifically, to the horizontal beam 24 of the support 23, so that one sensor 19 is on the front side of the reference point 14 and the other sensor 20 is on the back side of the reference point 14, in the machine direction MD of the rear box 13.

In addition, the sensors 19, 20 are adapted from their first attachment point 19.1, 20.1 on the side of the reference point 14 to the angle & with respect to each other. Angle o is less than 90 degrees. This can be determined, for example, by the distance D between the attachment points fitted to the sensors 19, 20 on the horizontal beam 24 belonging to the support 23.

The sensors 19, 20 are in the arrangement 10 now also in such a way that they or their imagined extensions intersect each other when elongated. Now this happens from the first attachment points 19.1, 20.1 of the sensors 19, 20, where they are attached to a common

S 25 in tee, reference point 14.

S

2 Sensors 19, 20 are adapted from their attachment points 19.1, 19.2,

E 20.1, 20.2 articulated, i.e. allowing movement to arrangement 10. — Articulation takes place to reference point 14 and support point 23

S 30 to horizontal bar 24. The hinged mounting of the sensors allows refe-

S rence point 14 and thus also the twisting of the upper lip 17. >”

Furthermore, the arrangement 10 also includes means 16 for externally supporting the reference point 14 in connection with the upper lip 17 of the tail box 13, where also the tip strip 12 is movably closed in connection with the lip opening 30 by actuators 34 via the spindle 35. The means 16 for supporting the reference point 14 include, in the case according to the application form, a stem 31 and a suspension 32 arranged for it. With the suspension 32, the stem 31 can be adapted to be attached to the top lip 17 of the end box 13 adapted to be moved. In Figures 2 and 3, the suspension 32 is shown with crossed lines for clarity. Instead of the upper lip 17, we can also talk about the body of the upper lip 17.

The reference point 14 is adapted in the presented embodiment to the connection of one end of the stem 31, being now the first end of the stem 31, which also has the attachment points of the sensors 19, 20, to which they are hingedly attached from their first attachment point 19.1, 20.1. Thus, the reference point 14 is brought from the upper lip 17 and even more specifically, from the tip of the tip strip 12 to the outside of the end box 13, to its side. Being at the opposite end of the stem 31, the other end of the stem 31 is in turn attached to the vertical support 32.1 belonging to the suspension 32. Fastening can take place through the elongated oval hole in the stem 31 with two fasteners. In this way, the 0 reference point 14 at the other end of the stem 31 is always obtained both vertically and horizontally

S 25 easily aligned on the same line as the 12 tips of the tip list

with S when installing it in the tail box 13. 3

E The suspension 32 also includes a transverse structure 32.2 fitted to the end of the vertical support 32.1, on which the machine guide is supported

S 30 nen MD fastening beam 32.3. Fastener bar 32.3 follows the following

I hit the movement of the upper lip 17 of the tail box 13 when, for example, 5 lip differences are changed.

According to one application, the sensors 19, 20 are distance sensors, more specifically linear sensors, such as LVDT sensors, for example. In this case, the sensors 19, 20 are elongated. In addition, the solution according to the invention does not require that the sensors 19, 20 should have special trajectories. In this case, the movement of the upper lip 17 and the tip 12 is transmitted to the sensors 19, 20 in all situations without the possibility of jamming.

The arrangement 10 also includes a data transmission connection 11 adapted between the sensors 19, 20 and the measuring electronics 22 arranged for them. The measuring electronics 22, including, for example, the sensor amplifiers, the display, the compensation calculation and the calibration of the sensors, are adapted to send the measurement result based on the measurement performed by the sensors 19, 20 to the machine control automation 25. The measurement values of the lip gap and lip gap can be transferred from the arrangement 10 to the machine control system 25, for example as a milliampere message.

When moving the lip, the length of the sensors 19, 20 is always known and, in addition, the support of the sensors 19, 20 is adapted so that the measurement D between the attachment points 19.2, 20.2 of the sensor parts opposite to the reference point 14 is always known, the first of the sensors 19, 20 the change in the position of the attachment points 19.1, 20.1, i.e. also the reference point 14, is

S 25 can be calculated with formulas based on trigonometry horizontal and

S for vertical changes, i.e. changes of the lip gap and lip gap. More generally, we can talk about triangulation. Here

The formulas used in the calculation of E can be, for example, the following:

S 30

O

N x pos = ((BRACKET WIDTH”2) - (B Stroke”2) + (A Stroke”2)) / 5 (2*BRACKET WIDTH);

and y pos = sart ((A Stroke 72) - (x pos”2));

In the formulas, A Stroke and B Stroke are the current lengths of the sensors 19 and 20, and Bracket Width is the known distance D between the sensors 19, 20 in the horizontal bar 24. The lengths of the sensors 19, 20 can be, for example, 300 - 700 mm and the attachment points of the sensors 19, 20 The standard distance D between 19.2, 20.2 can be, for example, 400 —- 500 mm. The notation sqrt in the latter formula, on the other hand, means square root.

In the arrangement 10 according to the invention, the movement of the upper lip 17 and the tip strip 12 is transferred to the measuring instruments 15, i.e. the sensors 19, 20 directly. With the invention, for example, the twisting of the upper lip 17 has no error-causing effect.

The invention achieves numerous different advantages. The invention increases the accuracy of measuring the lip gap and lip gap and gets rid of cumbersome and problem-causing compensation calculations. In addition, the solution also takes into account the elastics of the upper lip area, so separate compensation is not necessarily needed in that regard either. Implementation according to the invention facilitates, for example, planning, installation and commissioning. Most

S 25 components can be standardized and project-specific

The contribution of snittelu remains small in the invention. In addition, the structure is 2 inexpensive and easy to install

to the tail box in E.

S 30 Calibration of the measurement is also easy. You don't need to move

N goes to the extremes, but it is enough that one exact point is given to the calibration software. This saves calibration time and makes it easier, for example, to replace a broken sensor 19, 20.

The measurement can be easily calibrated by measuring, for example, the actual lip opening and lip gap readings from the lip opening, and these can be entered directly into the calibration program. For calibration, a measuring device can also be made, which is inserted into the lip opening. When the lip is driven to the point indicated by the measuring aid, for example 10 lip opening, 10 lip difference, then the relevant readings can be entered directly into the calibration program without special measurements. In terms of costs, arrangement 10 is a relatively inexpensive and compact solution.

The arrangement 10 according to the invention is applicable to a paper, cardboard and tissue paper machine as well as a pulp drying machine, generally fiber web machines. The arrangement is suitable for all tail boxes, but especially for flat wire tail boxes.

It should be understood that the above explanation and the related pictures are only intended to illustrate the present invention. The invention is thus not limited only to the embodiments presented above, but many different variations and modifications of the invention that are possible within the scope of the inventive idea defined by the accompanying protection requirements will be obvious to the person skilled in the field.

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Claims (5)

PROTECTION REQUIREMENTS 1. Arrangement for measuring the position of a tip strip in the inlet chute of a fiber web machine, which arrangement (10) comprises - a reference point (14) which can be arranged to follow the tip strip (12), - measuring devices (15) for determining the reference point's (14) ) position from the outside of the inlet chute (13), characterized in that — the measuring devices (15) include two sensors (19, 20) for determining the position of the reference point (14) in two dimensions, = each of the sensors (19, 20) is equipped with two attachment points (19.1, 19.2, 20.1, 20.2), of which —- on their first attachment point (19.1, 20.1) the sensors (19, 20) are arranged to follow the reference point (14), - on their second attachment point (19.2, 20.2 ) the sensors (19, 20) are arranged in connection with the fixed frame construction (49) of the inlet chute (13), so that the distance (D) between the other attachment points (19.2, 20.2) is constant. 2. Arrangement according to protection requirement 1, characterized in that suspension (23) has been arranged for the 0 sensors (19, 20) on the fixed frame construction (49) of the inlet chute (13), by means of which the sensors (19, 20 ) other attachment points (19.2, 20.2) have been arranged in S horizontal configuration. x a — 3. Arrangement according to protection requirements 1 or 2, characterized in that the S 30 sensors (19, 20) have been arranged in their first attachment points S (19.1, 20.1) directly on the reference point (14). >" 4. Arrangement according to one of the protection requirements 1 - 3, characterized in that the sensors (19, 20) have been arranged in their first attachment points (19.1, 20.1) on the side of the reference point (14) at an angle (2) in relation to each other, which angle (0) is less than 90 degrees. 5. Arrangement according to one of the protection requirements 1 - 4, characterized in that the sensors (19, 20) are arranged in their second attachment point (19.2, 20.2) in connection with the fixed frame structure (49) of the inlet chute (13) say that one sensor (19) is on the front of the reference point (14) and the other sensor (20) is on the front of the reference point (14) back side, in the machine direction (MD) of the inlet tray (13) . O N O N O <Q oO N I jami a 0 O <t O N O N D