EP0987365B1 - Sealing device and process for sealing pressure zones in a papermachine - Google Patents

Description

The invention relates to a sealing device for lateral sealing at least one overpressure adjacent to a moving surface or Vacuum zone in a paper machine with at least one Sealing element, at least in some areas in a receiving area arranged a holder and relative to the moving surface is movable to the holder.

The invention further relates to a method for lateral sealing at least one overpressure adjacent to a moving surface or Vacuum zone in a paper machine by means of a sealing device, which comprises at least one sealing element, at least in regions is arranged in a receiving area of a holder and is moved relative to the holder for application to the moving surface.

Such sealing devices and methods serve, for example the interior of a suction box, which is under negative pressure, whose side walls are provided with the sealing device, opposite to seal the environment by sealing the rotating elements against the Jacket of a suction roll over which a paper web to be dewatered is guided, pressed in such a way that the sealing element is optimal lies against the jacket and a good sealing effect is achieved.

From US 5,580,424 it is known to arrange one in a holder Sealing element with a separate piston that counteracts by means of a spring the sealing element is pressed into the holder. The feather is designed such that a movement of the sealing element in the direction of a Roll jacket not prevented, but the sealing element is held when the pressure in a pressure hose is removed.

In a device known from DE-AS 1 135 745 are legs of a weather strip in a space between walls of one Guide for the weather strip arranged, the thickness of the Each leg is slightly less than the width of the space between the Walls. To reduce air passage is between the weather strips and a small one on each of the outer walls of the guide pneumatic sealing provided in the form of a rubber hose, which is connected to a compressed air source and to the sealing strip to create a seal.

From US 2,649,719 it is known in the side walls of a holder for to form a sealing strip of grooves and sealing tubes in these grooves insert, which roll in the pressing direction in the groove can. The sealing strip can become loose due to the unrolling Tubes within that formed by the side walls of the holder Move the slot freely.

In a device known from DE-AS 1 146 350 are on the inner surface of a roller jacket press-on sealing strips in the body of a Suction chamber loosely guided and inside the suction chamber of pressure chambers and supported outside of ribs.

It is the problem (object) on which the invention is based, a sealing device as well as a method of the type mentioned at the beginning create the simplest possible one during operation consistently good sealing of the pressure zone while avoiding a allow excessive contact pressure.

This task is solved by the characteristics of the independent Device claim and in particular in that the receiving area designed as a clamp receptacle and the sealing element via clamping surfaces the clamping receptacle is subjected to a clamping force.

This creates a frictional connection between the holder and the sealing element, which holds the sealing element securely in the respective Can hold position with respect to the moving surface and at the same time for provides a seal between the holder and the sealing element.

Furthermore, it is possible to measure the clamping force in such a way that the sealing element first with a to overcome the clamping force sufficiently large contact pressure is applied to the moving surface and then the contact pressure can be reduced, whereupon the sealing element by the of the holder on the clamping surfaces on the Sealing element exerted clamping force in its set sealing position is held.

According to a preferred embodiment of the invention, at least a clamping surface partially formed by a clamping member.

Such a clamping member can be tailored to the respective conditions of use be adjusted. If, for example, with vibrations of the moving Surface, in particular a rotating jacket of a suction or Blowing roller, which affect the position of the sealing element, this can lead to the frictional connection between the holder and the clamping element contributing to the sealing element is elastically deformable be designed, whereby the vibrations transmitted to the sealing element can be caught. The appearance of a so-called "Slip stick" effect "is effectively prevented in this way, so that the sealing element in relation to the vibrations in its set position of the roll shell remains. An excessive contact pressure or Surface pressure between the sealing element and the roll shell is avoided in this way, resulting in less wear of the sealing element has the consequence.

If, on the other hand, no disturbing vibrations are to be expected, and in particular desirable for suction rolls with poor concentricity "Slip stick" effect should be promoted, the clamping member be made of a material of low elasticity.

The object underlying the invention is also by the Features of the independent process claim and in particular thereby solved that the receiving area is designed as a clamp receptacle and the sealing element during its movement relative to the holder and in the created state over clamping surfaces of the clamping receptacle with a Clamping force is applied.

Preferred embodiments of both the sealing device according to the invention as well as the sealing method according to the invention are specified in the subclaims, the description and the drawing.

Fig. 1a

eine Seitenansicht einer Dichtungseinrichtung gemäß einer ersten Ausführungsform der Erfindung,

Fig. 1b

einen bezüglich Fig. 1a vergrößerten Ausschnitt einer gegenüber der Ausführungsform von Fig. 1a modifizierten Dichtungseinrichtung gemäß der Erfindung,

Fig. 2

eine weitere Ausführungsform einer erfindungsgemäßen Dichtungseinrichtung,

Fig. 3a

ein Diagramm zur prinzipiellen Erläuterung der auf ein Dichtelement der erfindungsgemäßen Dichtungseinrichtung einwirkenden Kräfte,

Fig. 3b

mögliche zeitliche Verläufe des in einem Anpreßdruckschlauch der erfindungsgemäßen Dichtungseinrichtung herrschenden Drucks,

Fig. 4

eine Seitenansicht einer weiteren Ausführungsform einer erfindungsgemäßen Dichtungseinrichtung, und

Fig. 5

eine Seitenansicht einer gegenüber der Ausführungsform von Fig. 4 modifizierten Ausführungsform einer Dichtungseinrichtung gemäß der Erfindung.

The invention is described below by way of example with reference to the drawing. Show it:

Fig. 1a

a side view of a sealing device according to a first embodiment of the invention,

Fig. 1b

FIG. 1 a enlarged detail with respect to FIG. 1 a of a sealing device according to the invention, modified compared to the embodiment of FIG. 1 a,

Fig. 2

another embodiment of a sealing device according to the invention,

Fig. 3a

1 shows a diagram for the basic explanation of the forces acting on a sealing element of the sealing device according to the invention,

Fig. 3b

possible temporal profiles of the pressure prevailing in a pressure hose of the sealing device according to the invention,

Fig. 4

a side view of another embodiment of a sealing device according to the invention, and

Fig. 5

a side view of a modified from the embodiment of FIG. 4 embodiment of a sealing device according to the invention.

The sealing device according to the invention according to Fig. 1a serves to separate two pressure zones P ₁ , P ₂ , which are adjacent to the inner wall of a casing 20 rotating during operation in the direction of the arrow relative to the sealing device, which is part of a suction roll, not shown, of a paper machine and a moving surface represents in the sense of the invention. The jacket 20 is provided with holes 21 through which moisture can be extracted from a paper web to be dewatered.

The sealing device is assigned to a suction box, not shown, in the interior of which there is a pressure P ₁ during suction operation which is less than the ambient pressure P ₂ . At a distance from the sealing device shown in FIG. 1 a in the circumferential direction, a further sealing device designed according to the invention is provided, which seals the interior of the suction box to the other side.

The sealing device comprises a holder 10 which is in one plane perpendicular to the axis of rotation of the suction roll a U-shaped cross section has and is preferably substantially over the entire length of the roller extends. In the holder 10 is a sealing element 15, which as well formed sealing strip extending approximately over the entire length of the roller is inserted so precisely that side walls 11, 12 of Holder 10, which has a channel-like receiving area 17 for the sealing element Limit 15 laterally, flat on the outer walls of the sealing element 15 concerns.

The width of the receiving channel 17 of the holder 10 is dependent on the width of the sealing element 15 and the material properties of the sealing element 15 dimensioned such that the sealing element 15 tight in the Holder 10 is seated and freely movable neither in the axial nor in the radial direction is.

In this way, the receiving area 17 forms a clamping receptacle for the sealing element 15. The surfaces facing the sealing element 15 the side walls 11, 12 of the holder 10 form clamping surfaces of the Clamping receptacle for a frictional connection between the Sealing element 15 and the holder 10 and the sealing element 15 with a static friction or clamping force.

As indicated by the dashed line in Fig. 1a, the sealing element 15 comprise two different sections 15a, 15b. One with the Sheath 20 cooperating wear section 15a may differ in terms of the material from a clamping portion 15b with which the Sealing element 15 is clamped in the holder 10, distinguish. To this In this way, the material of the two sections 15a, 15b of the sealing element 15 can be optimally adapted to the respective function to be performed. The wear section 15a is on one side with a bevel 16 Mistake.

Between the bottom of the receiving channel 17 and the sealing element 15 a pressure hose 55 is arranged, which is also about extends the entire roll length and is connected to a fluid pressure source 70 is in connection with a fluid reservoir, not shown stands. The flow connection between the fluid pressure source 70 and the pressure hose 55 interrupted become.

By increasing the pressure P _F prevailing inside the pressure hose 55, the pressure hose 55 expands, so that in this way the sealing element 15 is pushed out of the holder 10 against the clamping force exerted by the side walls 11, 12 of the holder 10 on the sealing element 15 and can be applied to the jacket 20. The contact pressure F exerted by the contact pressure hose 55 on the sealing element 15 is indicated by an arrow in FIG. 1a.

The sealing element 15 is preferably applied to the jacket 20 in such a way that there is a minimal sealing gap, which is sufficient for a sufficient Tightness ensures.

According to the modification shown in FIG. 1b, at least one of the Side walls 11, 12 of the holder 10 at least one in the longitudinal direction of the holder 10 extending groove 40 may be formed, in which a sealing element 30 is arranged with a circular cross section, for example is designed as an O-ring.

The side of the sealing element 30 facing the sealing element 15 forms part of the clamping surface and thus contributes to frictional engagement Connection between the holder 10 and the sealing element 15 at. The Sealing element 30 can thus be referred to as a clamping member.

A movement of the sealing element 30 in the direction of the movement the sealing element 15 is prevented in that in this direction the width of the groove 40 of the dimension of the sealing element 30, d. H. corresponds to the diameter of the sealing element 30.

The embodiment of the sealing device according to the invention FIG. 2 differs from the embodiment according to FIG. 1a characterized in that the holder 10 is only partially in a receiving channel shown suction box 65 arranged and relative to the suction box 65 is movable, which is indicated by the double arrows.

This configuration enables the distance between to be preset the holder 10 and the jacket 20 of the suction roll, so that a comparatively slight increase in pressure in the pressure hose 55 is sufficient, to apply the sealing element 15 to the jacket 20.

Another advantage is that the contact pressure hose 55 only needs to change its volume due to the slight pressure increase without having to be stretched in order to bring about the necessary lifting movement of the sealing element 15. As a result, there is a linear relationship between the pressure P _F and the contact pressure between the sealing element 15 and the jacket 20 without dependence on the contact path.

Just as the holder 10 forms a clamping receptacle for the sealing element 15, can also the suction box 65 as a clamp receptacle in the sense of the invention be designed for the holder 10.

The holder 10 of the other described embodiments of the Sealing device according to the invention can for the purpose of a Coarse adjustment can be made adjustable relative to the jacket 20.

Fig. 3 serves to explain the acting on the sealing element 15 Forces, where in the diagram the forces over the extension of the Sealing element 15 along the axis of rotation of the suction roll, d. H. across the roll width Bw are applied.

Fp denotes the force referred to below as the bending force, which is required in order to adapt the sealing element 15 to the contour of the roll shell 20, which can deviate from a straight line, for example due to the roll deflection. While the bending force F _{P is shown} in FIG. 3a as being approximately constant over the length of the sealing element 15, a deviating course of the bending force F _P can occur in practice.

The static frictional force acting by clamping the sealing element 15 in the holder 10 between the sealing element 15 and the holder 10 is designated by F _R in FIG. 3a, a case being assumed here in which the static frictional force F _{R is} greater than the bending force F _P is. The static friction force F _R is also referred to below as the clamping force.

In order to be able to press the sealing element 15 onto the jacket 20 in such a way that the sealing element 15 bears sealingly against the jacket 20 over the entire length of the suction roll, the pressure P _F in the contact pressure hose 55 must be increased to such an extent that the contact force F is greater than the sum F _R + F _P and is therefore in the hatched area of FIG. 3a.

3b, in which the pressure P _{F is shown} in the interior of the contact pressure hose 55 over the time t, an example for the case F _R > F _{P is shown} with a solid line.

After the sealing element 15 has been adapted to the contour of the jacket 20 under the action of a constant high pressure P _F, the pressure P _F - and thus the contact force F - is brought to a constant low, preferably slightly above, between times t ₁ and t ₂ Reduced zero value. Since the static friction or clamping force F _{R is} greater than the bending force F _P , the sealing element 15 cannot move out of its optimally applied state, ie out of its desired sealing position. This means that only the clamping of the sealing element 15 between the side walls 11, 12 of the holder 10 maintains the state of optimal sealing between the sealing element 15 and the jacket 20.

3b shows the case F _R <F _{P in} a broken line in which the clamping force F _{R is} not sufficient to hold the sealing element 15 in its position adapted to the contour of the jacket 20. In this case, the pressure P _F in the contact pressure hose 55 is only reduced at most to such an extent that the contact force F corresponds at least approximately to the difference between the bending force and the clamping force, ie F ≈ F _P - F _R.

The static friction force F _R between the holder 10 and the sealing element 15 is in this case, to a certain extent, supported by the contact pressure F exerted by the pressure hose 55 on the sealing element 15 in order to overcome the bending force F _P and to seal the sealing element 15 over the entire length of the suction roll to press their coat 20.

If, according to a case not shown in FIG. 3b, vibrations of the casing 20 occur and are transmitted to the sealing element 15, this can lead to a temporal variation of the bending force F _P to be applied by the sealing device. In order to maintain the state of optimal sealing even in such a case, the fluid pressure P _F in the contact pressure hose 55 is set in such a way that the contact pressure is at least as great as the bending force at all times, ie that F ≧ F _P applies.

4 shows an embodiment of the sealing device according to the invention, which differs from the embodiments described above an arrangement of one as clamping members 130 Clamping pressure hose 50 and one that can be acted upon by the clamping pressure hose 50 Piston 60 is provided.

The clamping pressure hoses 50 and the pistons 60 each extend in the axial direction over the entire length of the roller inside the grooves 45, which are formed in the side walls 11, 12 of the holder 10 and for Sealing element 15 are open.

The sides of the pistons 60 facing the sealing element 15 each form part of the clamping surface for the sealing element 15 and thus contribute to frictional connection between the holder 10 and the sealing element 15 at.

The contact pressure hose 55 provided for applying the sealing element 15 to the jacket 20 of the suction roll and the two clamping pressure hoses 50 are connected to a common pressure circuit in which the pressure can be regulated by means of a fluid pressure source 70 and a valve 75. Consequently, the same fluid pressure P _F prevails in the contact pressure hose 55 and in the clamping pressure hoses 50 when the sealing element 15 is applied or pressed onto the moving surface 20.

If the sealing element 15 has reached the desired sealing position after application or pressing and the pressure P _{F is} reduced, check valves 85 prevent the pressure in the clamping pressure hoses 50 from dropping. The clamping force exerted by the clamping members 130 is consequently retained. Valves 90 serve to release pressure from the clamping pressure hoses 50 and thus to reduce or remove this clamping force.

4 also shows a pressure regulating or control device 80 which is connected to the pressure circuit in the region of the valve 75 and communicates with the pressure hose 55 and which is used to regulate or control the valve position as a function of the fluid pressure P measured by it in the pressure hose 55 _{F is} formed. Such a pressure control device can also be provided in the other described embodiments of the sealing device according to the invention.

With the embodiment according to FIG. 4, it is possible to specifically change the static friction or clamping force F _R on the clamping surface provided by the piston 60 as a function of the respective operating conditions, without the need for a separate fluid pressure circuit. The geometrical relationships and the properties of the clamping pressure hoses 50, the pistons 60 and the contact pressure hose 55 can be selected according to the respective application and in particular coordinated with one another.

The embodiment according to FIG. 4 allows first of all to work with a comparatively high pressure P _F , which is necessary to move the sealing element 15 relative to the holder 10, and - when the desired sealing position of the sealing element 15 is reached - the pressure P. _F to reduce. Since a pressure drop in the clamping pressure hoses 50 is prevented by the check valves 85, the clamping force exerted by the clamping members 130 on the sealing element 15 is maintained, so that the sealing element 15 is still held in its sealing position.

The pistons 60 can be designed to be elastically deformable and consist of one each produced the desired elasticity material become. A high elasticity of the piston 60 is advantageous when vibrating of the roll shell 20 is to be expected, which on the sealing element 15 are transmitted. Such vibrations can then be caused by the pistons 60 are recorded so that no "slip stick" effect occurs and the sealing element 15 in the optimal sealing position with respect to the Jacket 20 remains.

On the other hand, a low elasticity of the pistons 60 is advantageous if none Vibrations of the roll shell 20 are to be expected and the sealing device used on suction rollers with poor concentricity is because in this way the "slip stick" effect desired in such cases is promoted.

The embodiment of a sealing device according to the invention shown in FIG. 5 differs from the embodiment according to FIG. 4 in that a clamping member 130 comprising a clamping pressure hose 50 and a piston 60 is provided only in one side wall 11 of the holder 10, wherein in the clamping pressure hose 50 during the Applying or pressing the sealing element 15 against the moving surface 20 is the same pressure P _F as in the contact pressure hose 55.

LIST OF REFERENCE NUMBERS

10

holder

11.12

Side wall

15

sealing element

15a

wear section

15b

clamping section

16

bevel

17

Recording area, recording channel

20

Moving surface, coat

21

drilling

30

Clamping element, sealing element

130

clamping member

40, 45

groove

50

Clamping pressure hose

55

Anpreßdruckschlauch

60

piston

65

suction box

70

Fluid pressure source

75

Valve

80

Pressure regulating or control device

85

check valve

90

Valve

P ₁ , P ₂

pressure zones

P _F

fluid pressure

F

, contact pressure

F _R

Clamping force, static friction

F _P

bending force

bw

roll width

Claims (27)

1. Sealing device for the lateral sealing of at least one positive-pressure or negative-pressure zone (P₁, P₂) adjoining a moving surface (20) in a paper machine, using at least one sealing element (15) which, at least in some regions, is arranged in a holding region (17) of a holder (10) and can be moved relative to the holder (10) in order to be placed on the moving surface (20),
   characterized in that
   the holding region (17) is formed as a clamping holder and the sealing element (15) is acted on via clamping surfaces of the clamping holder with a clamping force (F_R) which is greater than a bending force (F_P).
2. Sealing device according to Claim 1, characterized in that, at least in a plane perpendicular to the direction of contact, the sealing element (15) at least substantially completely fills the holding region (17).
3. Sealing device according to Claim 1 or 2, characterized in that the holding region is formed as a holding channel (17) which is open towards the moving surface (20) and which preferably has an approximately square or rectangular free inner cross-sectional area, the side faces bounding the holding channel (17) being formed as clamping surfaces.
4. Sealing device according to at least one of the preceding claims, characterized in that at least one clamping surface is partly formed by a clamping element (13; 130) which is preferably arranged in a groove (40; 45) which is formed in a side wall (11, 12) of the holder (10) and is open towards the sealing element (15).
5. Sealing device according to Claim 4, characterized in that the clamping element is formed as a sealing element (30).
6. Sealing device according to Claim 4 or 5, characterized in that the clamping element (30; 130) is elastically deformable.
7. Sealing device according to at least one of Claims 4 to 6, characterized in that the clamping element (130) comprises a clamping pressure tube (50) arranged in particular between the sealing element (15) and a side wall (11, 12) bounding the holding region (17).
8. Sealing device according to at least one of the preceding claims, characterized in that the sealing element (15) can be placed on the moving surface (20) by means of at least one contact pressure tube (55), which is arranged in particular between the sealing element (15) and a boundary surface of the holding region (17) facing away from the moving surface (20).
9. Sealing device according to Claim 7 or 8, characterized in that the pressures prevailing in the contact pressure tube (55) and in the clamping pressure tube (15) are approximately equally high, at least while the sealing element (15) is being placed on or pressed against the moving surface (20).
10. Sealing device according to at least one of Claims 7 to 9, characterized in that the contact pressure tube (55) and the clamping pressure tube (50) are connected to a common pressure circuit.
11. Sealing device according to at least one of Claims 7 to 10, characterized in that the clamping pressure tube (50) is arranged in a groove (45) formed on the surface of the side wall (11, 12).
12. Sealing device according to at least one of Claims 7 to 11, characterized in that a piston (60) that can move in the groove (45) is arranged between the clamping pressure tube (50) and the sealing element (15).
13. Sealing device according to Claim 12, characterized in that the piston (60) is produced from a material having a low elasticity.
14. Sealing device according to at least one of the preceding claims, characterized in that the sealing element (15) comprises a wearing section (15a) interacting with the moving surface (20) and clamping section (15b) interacting with the holder (10), the wearing section (15a) and the clamping section (15b) being produced from different materials.
15. Sealing device according to at least one of the preceding claims, characterized in that the holder (10) can be moved relative to the moving surface (20) with a component parallel to the contact direction.
16. Sealing device according to at least one of the preceding claims, characterized in that the holder (10) is mounted on a suction or blower box (65), in particular in a sprung manner, such that it can move.
17. Sealing device according to at least one of the preceding claims for the lateral sealing of at least one pressure zone (P₁, P₂) adjoining the inner or outer wall of a rotating shell (20) of a suction or blower roll or a moving belt.
18. Sealing device according to at least one of the preceding claims for use between a suction or blower box (65) and the rotating shell (20) of a suction or blower roll or a moving belt.
19. Sealing device according to at least one of the preceding claims, characterized in that the sealing element (15) is formed as a sealing strip extending at least substantially over the entire length of the roll.
20. Sealing device according to the precharacterizing clause of Claim 1, characterized in that the sealing element (15) is acted on via clamping surfaces of the holder (10) with a clamping force (F_R), at least one clamping surface being at least partly formed by a clamping element (130) which is preferably arranged in a groove (45) formed in a side wall (11, 12) of the holder (10) and open towards the sealing element (15), and which comprises a clamping pressure tube (50) arranged in particular between the sealing element (15) and a side wall (11, 12) bounding the holding region (17), it being possible for the sealing element (15) to be placed on the moving surface (20) by means of at least one contact pressure tube (55), which is arranged in particular between the sealing element (15) and a boundary surface of the holding region (17) facing away from the moving surface (20), and the pressures prevailing in the contact pressure tube (55) and in the clamping pressure tube (50) being approximately equal, at least while the sealing element (15) is being placed on or pressed against the moving surface (20), and in particular the contact pressure tube (55) and the clamping pressure tube (50) being connected to a common pressure circuit.
21. Method for the lateral sealing of at least one positive-pressure or negative-pressure zone (P₁, P₂) adjoining a moving surface (20) in a paper machine by means of a sealing device which comprises at least one sealing element (15), which is arranged in a holding region (17) of a holder (10) and is moved relative to the holder (10) in order to be placed on the moving surface (20), characterized in that the holding region (17) is formed as a clamping holder and, during its movement relative to the holder (10) and in the state in which it is in contact, the sealing element (15) is acted on via clamping surfaces of the clamping holder with a clamping force (F_R) which is greater than a bending force (F_P).
22. Method according to Claim 21, characterized in that the sealing element (15) is clamped in with an at least substantially time-constant clamping force (F_R).
23. Method according to Claim 21, characterized in that the clamping force (F_R) is varied as a function of the distance of the sealing element (15) from the moving surface (20) and/or as a function of a contact force (F) with which the sealing element (15) is acted on in order to place it on the moving surface (20).
24. Method according to at least one of Claims 21 to 23, characterized in that, after the sealing element (15) has been placed on the moving surface (20), a contact force (F) is set as a function of the ratio between the clamping force (F_R) and a bending force (F_P) required to match the sealing element (15) to the contour of the moving surface (20).
25. Method according to at least one of Claims 21 to 24, characterized in that, after the sealing element (15) has been placed on the moving surface (20), a contact force (F) is reduced.
26. Method according to at least one of Claims 21 to 25, characterized in that, after the sealing element (15) has been placed on the moving surface (20), in particular has been matched to the contour of the moving surface (20), a contact force (F) is reduced, in particular to approximately zero.
27. Method according to at least one of Claims 21 to 26, characterized in that a sealing device having the features of at least one of Claims 1 to 20 is used.

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