EP0887463B1 - Apparatus for dewatering a papermaking felt - Google Patents

Description

The invention relates to a device for dewatering a Paper machine certificates, in particular with the characteristics from the generic term of claim 1.

Such a paper machine felt is an endless felt belt, which in one Press section of a paper machine supports a fibrous web and Absorbs liquid in the press zone from the fibrous web. Except for The press zone tends to return water to the fibrous web. However, this rewetting is not desirable.

For this reason, solutions for dewatering felt tapes as in the US - A - 4698134 and GB - A - 2055409 developed in their However, effectiveness is unsatisfactory.

If you form a paper machine felt on two sides with a dense, fine-fiber, paper-side fleece and with a coarse, voids and Carrier layer containing breakthroughs, e.g. B. a plastic sieve, then can be done in a centrifugal field, in which the felt with the rough inside a convex path runs at high speed in the cavities stored water in a arranged inside the felt loop Spin off the drip pan. The spin starts only at one Velocity at which the centrifugal force turns that on Water retention capacity of the surface tension forces Felt exceeds. Therefore the centrifugation according to US - A - 3347740 is after connected with problems on the outside.

But if the fleece layer is made so dense that there is no more air can pass through, then the prerequisite for hurling the Still not given water because there is no air between fleece and Water layer can penetrate. Only gradually form in the surface Water prominences from the water from the surface tension Soak up fabric meshes and thereby a convection movement in Go through the exchange of water and air in the Carrier layer takes place. Because of the mostly short inside convex Wrapping zones in the course of a paper machine felt can occur of this initial loss of time until the formation of convection only one limited amount of water can be thrown off.

It is an object of the present invention to remedy this deficiency and in particular also the spinning off of larger amounts of water to enable at relatively low running speeds.

This object is achieved in that the Water surface in the sieve fabric by inflating many across the felt width distributed displacement medium or fluid jets in front of or in the convex Deflection zone is made wavy. The ripple arises from the fact that the Impulse of the impinging displacer fluid jets the liquid level in the impact areas, so that the water displaced there to a Thickening of the water layer leads in rows between the blow nozzles. This initiates an orderly convection movement, and it Protuberances arise in the thickened areas, the further water soak up and spin off. Can be used as displacement medium or fluid Water or air can be used. Depending on the local conditions, this can one or the other may be more advantageous.

The most favorable distance between neighboring blowing jets in Cross machine direction is 2 to 12 mm. The cheapest distance between the nozzles from the felt surface is less than 20 mm. So that last distance can always be the same size across the width of the felt, with nozzles provided blowpipe, also called a nozzle pipe, with a sliding block or be provided with a sliding surface that is lightly pressed against the felt, so that it lies across the entire width. This pressure is natural only makes sense if the felt in the pressing area is not yet from the Opposite side is supported.

Instead of a nozzle tube, it is conceivable, a so-called To use a rinsing blower device. This has at least one carrier, which is connected to an air supply opening and openings, for example in the form of slots or through openings, through which, for example, air acts on the felt surface. Preferably the rinsing blower device has a box-shaped one, for example Support body, which is provided with a covering, the surface of which The active surface with the felt forms and openings in the form of blow slots Displacement fluid supply or application of the felt. The Air supply opening, which is preferably arranged laterally on the support element is then preferably through openings with those in the covering integrated blow vents coupled. Preferably always one A plurality of blow slots connected to a through hole. The Through opening itself can be in cross-section in the installed position be executed differently in the vertical direction. The blowing air arrives then through the air supply opening, the through openings into the blow slots and blows the air under the webs between the blow slots through the porous inner layers of the felt provided in the covering Longitudinal grooves, which are also provided on the rinsing blower device and that are open to the atmosphere.

The covering is preferably made of wear-resistant in the form of a shoe Made of material, such as polyethylene. To realize a optimal fit of the felt band on the surface of the flushing blower these are curved in the running direction of the felt belt.

To further intensify the drainage of the felt belt and thus to Increasing the paper dry content as well as reducing the The drainage device according to the invention can consume energy to intensify the drainage by centrifugal force with others Drainage systems can be combined. For example it is conceivable, further parts of the liquid from the felt band, which are not through Centrifugal force have been thrown off via wipers and / or Devices for generating a suction effect, for example one on the corresponding surface of the felt tape adjacent suction tube or of a corresponding foil. The concrete constructive Design or combination with other drainage systems is at the discretion of the professional and usually depends on the Operational requirements.

Fig. 1:

Anordnung eines Düsenrohres in einer Filzschlaufe;

Fig. 2:

Detailquerschnitt zu Figur 1 in Schnittlinie II-II;

Fig. 3:

Detaillängsschnitt aus Figur 1;

Fig. 4:

Detaillängsschnitt mit unterstütztem Filz;

Fig. 5:

Detaillängsschnitt mit Stützleiste;

Fig. 6:

Die Verwendung einer erfindungsgemäßen Entwässerungseinrichtung in der Pressenpartie einer Papiermaschine;

Fig. 7:

Anordnung eines Düsenrohres in einer Filzschlaufe in Kombination mit zusätzlichen Wasserabstreifvorrichtungen;

Fig. 8:

Anordnung einer Spülbläsereinrichtung in einer Filzschlaufe zur Erhöhung der Intensität der Entwässerung und Kombination mit zusätzlichen Abstreich- und Ansaugvorrichtungen zur Intensivierung der Entwässerung;

Fig. 9:

Spülbläsereinrichtung im Querschnitt;

Fig. 10:

Ansicht III-III entsprechend Figur 9;

Fig. 11:

Ansicht von unten entsprechend Figur 10.

The invention is explained in more detail with reference to FIGS. 1 to 11. Show it:

Fig. 1:

Arrangement of a nozzle tube in a felt loop;

Fig. 2:

Detailed cross section to Figure 1 in section line II-II;

Fig. 3:

Detail longitudinal section from Figure 1;

Fig. 4:

Longitudinal detail with supported felt;

Fig. 5:

Longitudinal detail with support strip;

Fig. 6:

The use of a drainage device according to the invention in the press section of a paper machine;

Fig. 7:

Arrangement of a nozzle tube in a felt loop in combination with additional water wiping devices;

Fig. 8:

Arrangement of a rinsing blower device in a felt loop to increase the intensity of the drainage and combination with additional wiping and suction devices to intensify the drainage;

Fig. 9:

Rinsing blower device in cross section;

Fig. 10:

View III-III corresponding to Figure 9;

Fig. 11:

Bottom view corresponding to Figure 10.

In FIG. 1, 1 is a felt running in the direction of arrow 7, which has an outer guide roller 2 loops around, which is rotatably mounted on end pins 2 '. The dash-dotted line 1 'shows schematically that the felt is an endless belt. The path of the felt in area 1 'can be selected as desired, and in this area there are also contain other elements influencing the felt, e.g. in Wet presses are common. From the periphery of the felt 1 in the area of the roller 2 thrown water is in a drip pan 3, which over the entire width of the felt extends, collected and through a side Drain 4 led out of the felt loop. Shortly before the emergence of the felt 1 on the roller 2 is from a blowpipe 5 with a variety of over Wide distributed nozzles 6 displacer fluid against the inside of the felt blown.

A needle spray device for keeping clean is also preferred the inside 1a of the felt 1 is provided. However, there is a need Not. The needle spray device is for example as a traversing Needle spray tube 51 executed. This means that the needle spray tube 51, which is usually mounted on a frame, by adjusting the Frame across the felt width with respect to its location relative to the felt 1 or Inside 1a is adjustable adjustable transversely to the direction of felt. The traversing needle spray tube 51 is the nozzle 6 in the felt running direction 7 downstream. In the case shown, the assignment of Needle spray tube 51 to the outer guide roller 2 in its wrapping area with felt 1, i.e. after the emergence of the felt 1 on the roller 2. There is but also the theoretical possibility, not shown here, that traversing needle spray tube 51 in the felt belt running direction 7 between the Point of action of the nozzles 6 on the inside 1a of the felt 1 and Arrange run-up point of the felt on the outer guide roller 2.

A traversing needle spray tube 51 is also conceivable, wherein the adjustment frequency according to the application requirements, i.e. especially free depending on the speed of the felt is preset or adjustable.

Another possibility is to provide a plurality of Needle injectors.

In FIG. 2, the felt 1 consisting of carrier layer 8 and fleece layer 9 is arranged above the blow pipe 5 with nozzles 6. By the impulse of the against The felt fluid blown into the felt underside the water in the Mesh up a fabric serving as a support layer 8 pushed away and dodges to the side so that the surface of the Water level 10 in the carrier layer 8 is wavy. If these furrows Water surface reaches the curved area 12 of the felt web 1, draw them, as can be seen in Figure 3, on a larger radius R with a higher one Centrifugal water ribs 13 further water from the Furrows after that due to the smaller radius r a smaller one Are subjected to centrifugal acceleration. That concentrated in the ribs 13 Water is thrown off.

So that the effect of the displacement fluid over the entire width of the felt is as possible is uniform, the blow pipe 5 can be used over the entire width, as in FIG. 4 shown to be applied to the felt. This is the distance between the openings the nozzles 6 from the surface of the felt 1 the same size everywhere.

In a variant, FIG. 5, the tube 5 with the slide shoe 14 is attached Sliding surface 15 pressed somewhat into the felt 1, with the same result that the distance of the openings of the nozzles 6 from the underside of felt 1 over the width is the same.

Fig. 6 shows a press section of a paper machine in the in a preferred embodiment, a drainage device for Water drainage from the inside of a circulating felt belt Centrifugal force, against which a displacement fluid is applied in front of the curved area the felt is blown, is used.

6 shows two press rolls 100, 102, one Form press zone 104. Each of the press rolls is rotated by one endless felt belt 106, 108 for example a strong double-sided felt belt, surround. In the press zone, liquid, especially water, passes from a fibrous web in the felt belt. With such a felt tape is on a carrier layer interspersed with openings and cavities is a fine one Needled nonwoven.

Each of the felt belts 106, 108 includes a drainage device 110, 112 with nozzles 114, 116 for applying the displacement fluid, and one Collecting pan 118, 120 for receiving the spun off water. The Paper web runs in the direction of the arrow and is shown Transfer take-off roller 122 to the press section. After pressing zone 104 the paper web follows the felt 108 and arrives at a belt 123. This leads the paper web to further press stations or to a dryer section.

By using the drainage devices 110, 112 with nozzles the felt tape can be drained more than before. In particular it is possible the drainage devices 110, 112 instead of directly to the Press rolls 100, 102 arranged means for discharging liquid use or in combination with a previously unachieved one To achieve drainage of the felt tape.

FIG. 7 illustrates a narrow section of a Press section another embodiment of a dewatering device for water removal from the inside of a circumferential felt 52 Centrifugal force, a displacement medium in front of the curved area or fluid is blown against the felt 52. The felt 52 is shown in the Case and others guided over the guide rollers 57.1 and 57.2. The direction of felt is with 7 designated. A nozzle tube 58 is provided which covers the surface in Base fabric of the felt 52 water in the invention Way waves. The nozzle tube 58 is in the direction 7 of the felt 52 in front of the Thrust point of the felt 52 arranged on the guide roller 57.1. That through that Nozzle tube 58 has corrugated water in the base fabric of its surface In the illustrated case, felt 52 is discharged in two ways. A first part is under the influence of centrifugal force in the wrap area of the Felt 52 with the guide roller 57.1, here designated U, at the points of Felt 52 thrown off, the part thrown off being designated 59, and another second part is through a stripping device, for example in the form of a substantially the entire width of the felt belt extending scraper 60 in the area of the drain of Felt belt 52 stripped from the guide roller 57.1, here designated 61. The Water thrown off at points 59 is against a baffle 70 deflected and via a guide plate 62 into a gutter 63, which preferably has a lateral outlet 64. That in the area the drain of the felt tape 52 stripped water is also on Baffle 62 derived in the gutter 63. The channel 63, the scraper 60, the baffle 70 and the baffle 62 are preferably on one common cross member 65 attached, which is also preferably extends over the entire width of the felt 52. The assignment of the Cross member 65 and the attached gutter 63, the baffle 70, the guide plate 62 and the scraper 60 to the felt 52 takes place in Felt running direction 7 such that the water is also in this direction, i.e. in Direction of felt is removed.

Furthermore, instead of a pipe suction device for cleaning the felt 52 Bar, for example in the form of a scraper bar 53, which Dirt is wiped off on the outside of the felt 71 in the direction of the arrow 54. This is through a moistening spray tube 55 or a so-called "duo-cleaner" loosened or loosened. The moistening spray tube 55 is shown in Felt running direction 7 arranged in front of the scraper 53. The scraper 53 is preferably attached to a height adjustable cross member 56 which also extends essentially across the width of the felt. On Cleaning spray tube 51 with several jets across the width cleans the Filzinnenseite.

FIG. 8 illustrates using a section of a press section a further embodiment of a drainage device according to the invention. The felt is labeled 201 here. This is, among other things, about the Guide rollers 202.1 and 202.2 out. The felt running direction is designated 7. Instead of a nozzle tube, in the case shown there is a rinsing blower device 203 provided. The concrete constructive structure as well as the function described in more detail in the following FIGS. 9 to 11. This includes a preferably box-shaped support body 214, which with a wear-resistant element, preferably a shoe made of polyethylene 204, is coupled or coated, which is essentially in the installed position extends into the area of the inside 201a of the felt 201. Preferably presses on the flushing blower device 203 with the shoe 204 made of polyethylene the felt 201. The arrangement in the overall system takes place in front of the guide roller 202.2, on which drainage is to take place. The purge blower device 203 further comprises one, preferably arranged laterally, Air supply opening 215 through which air with a pressure of about 1 to 5 kPa is blown in. The rinsing blower device performs the same function like those designated in FIGS. 1 to 6 with 5 and in FIG. 7 with 58 Blowpipes, but at a higher intensity level. in the Wrapping area of the guide roller 202.2 with the felt belt 201, here also designated U, a first part is due to the centrifugal force at 205 thrown off water from the felt 201 and a second part in one Area 206, which is attached to the outlet of the felt 201 from the guide roller 202.2 connects, i.e. lies outside the looping area, at the The front edge of a strip 207 scraped off. The bar 207 is in terms of their effective area 74 in this way compared to the felt 201, in particular the Inside 201a of the felt 201, arranged that this further one so-called Foilzwickel 208 between the back 80 of the bar 207 and the felt band 201, in which water from the felt 201 due to the Vacuum is sucked and derived via the bar 209 in the area 210 and is guided in a gutter 211. The gutter 211 has preferably also has a lateral outlet 212 and is at one Cross member 213 attached. In the case shown is inclined by the Arrangement of the strip 207 with respect to the felt band on the one hand from water stripped of the felt surface in the area 206 and over a surface 81 of the Catch 211 fed and also additionally by the Inclination of the bar creates suction in the so-called foil wrap 208 exploited. There are therefore three different drainage concepts used - centrifugal dragging in area 205, stripping via a bar in the area 206 and the suction effect in the area 208. Es not only a drainage concept is realized, but the by the ripple of the water surface generated according to the invention Inflation of many displacement medium or -Using fluid jets in front of or in the convex deflection zone remove as much liquid as possible from the felt.

Here too there is the possibility of arranging a needle spray tube 51 behind the flushing blower device 203 and in front of the drainage points Drainage due to centrifugal force on the guide roller 202.2. The Needle spray tube 51 takes on a cleaning function.

FIGS. 9 to 11 use one according to the invention Rinsing blower device 203 shown in detail. This has, as in FIG. 8 already explained, a preferably box-shaped carrier 214, which with a polyethylene covering 205, preferably in the form of a Polyethylene shoe, coupled or coated. The polyethylene shoe 205 forms the surface 222 of the rinsing blower device 203, which is preferably up to the area of the felt surface, in particular the Inside on the felt surface, extends or is contacted with it. to Enlargement of the effective surface 222 and the realization of a optimal contact of the felt tape on the surface 222 of the Polyethylene shoe is curved in the direction of the felt. The felt can then due to its longitudinal tension directly on the surface 222 come to mind. The coupling between box girder 214 and Covering 205 takes place, for example, via clamping devices 216. The blown air passes through the air supply opening 215 via the - in the installed position - bottom of the Box girder 214 incorporated openings 217 and preferably over as Blind holes 218 formed through openings in the polyethylene covering 205 in blow slots 219, which extend from these to the area of Extend surface 222 of covering 205. Regarding the execution of the Blow slots 219 and the connection between the box girder 214, in particular the air supply opening 215 and the blow slots 219 a variety of ways. The concrete constructive execution lies in At the discretion of the specialist and is carried out according to the operational requirements. In the simplest case, the connections are through openings and Slots realized. Preferably, a plurality of blow slots 219 are included a through opening 217 or blind hole 218. In this regard, reference is made to FIG. 10, from which it can be seen that the three blow slots 219a, 219b and 219c into the blind holes 218.1, which is connected to the through opening 217.1 in the box girder, lead. FIG. 10 illustrates a section from a view III-III corresponding to Figure 9. From this it can be seen that the over the Air supply opening 215 conveyed air, which passes through the through openings 217 and the blind holes 218 and the blow slots 219 comes under the Web 220 through the porous inner layers of the felt 201 in longitudinal grooves 221 reaches the atmosphere, which are open to the atmosphere. As the Arrows 223 in Figure 11 illustrate the liquid from the Base fabric of the felt from the areas of the blow slots 219 and Ribs 220 are blown into the areas of the open grooves 221 to make it so concentrated on the circumference of the left guide roller 202.2 in the region 205 more easily can be thrown off.

The slots 219 preferably have a semicircular cross section corresponding to the view shown in Fig. 9, and a rectangular Cross section corresponding to the view in FIG. 11.

The specifically selected combination of the invention Drainage device for intensifying drainage with others Drainage facilities, e.g. Scraper or scraper and the use of negative pressure depends on the requirements of the individual case.

The running direction 5 of the felt in FIG. 11 is either parallel to the slots 219, 221 or slightly inclined as indicated by arrow 7 '. The inclination of the The felt running direction to the slit direction is preferably slight, with an angle of less than 2 °.

This tendency is achieved either in that the entire flushing device 203 tilted from the perpendicular position of its axis 223 to the felt running direction becomes, as shown, or the axis 223 becomes right-angled to Leave the felt running and the slots 219 and 221 become Felt running direction 7 inclined.

Claims (14)

1. Press section having dewatering equipment (110, 112) for leading water away from the inside of an endless, circulating felt belt (1, 52, 201) by means of centrifugal force in a region with a complex curvature of the inner side (1a, 52a, 201a) of the felt belt into a water trough (3, 118, 120) or water channel (63, 212) arranged in the interior of the felt belt (1, 52, 201) so as to pick up the water thrown off, nozzles (6) distributed over the width on the inner side (1a, 52a, 201a) of the felt belt blowing a displacement medium or displacement fluid against the felt belt (1, 52, 201) in or upstream of the region of the deflection effecting the convex curvature.
2. Press section according to Claim 1, characterized in that the nozzles (6) are a constituent part of a machine-width blower pipe (5).
3. Press section according to either Claim 1 or 2, characterized in that the felt is supported on a sliding surface (15) provided on the blower pipe (5).
4. Press section according to Claim 1, characterized in that the nozzles (6) are a constituent part of a substantially machine-width washing and blowing device (203).
5. Press section according to Claim 4, characterized by the following features:

   5.1 the washing and blowing device (203) comprises a box-like supporting element (214) which is coated with or coupled to a wear-resistant covering (205);

   5.2 the box-like supporting element (214) has an air feed opening (215);

   5.3 the air feed opening (215) is coupled to the nozzles extending as far as that surface (222) of the wear-resistant covering (205) which points away from the box-like supporting element.
6. Press section according to Claim 5, characterized in that the nozzles (6) are formed by passage openings machined into the basic surface of the box-like supporting element (214) and blower slots (219) machined into the wear-resistant covering (205) and having a smaller width than the passage openings (218).
7. Press section according to either Claim 5 or 6, characterized in that the washing and blowing device (203) has waste-air slots which connect the surface (222) of the resilient covering (205) to the atmosphere.
8. Press section according to one of Claims 5 to 7, characterized in that the surface (222) of the resilient covering (05) of the washing and blowing device (203) is of curved design in the felt running direction (7).
9. Press section according to Claims 1 to 8, characterized in that the nozzles (6) have a spacing a of 2 to 12 mm from one another.
10. Press section according to Claims 1 to 9, characterized in that the openings of the nozzles (6) are 3 to 15 mm away from the felt surface.
11. Press section according to one of Claims 1 to 10, characterized in that, in or immediately downstream of the region with a complex curvature of the inner side (1a, 52a, 201a) of the felt belt, additional means of leading water away from the inside of the circulating felt belt (1, 52, 201) are provided.
12. Press section according to Claim 11, characterized in that the means comprise at least one wiper strip, which is operatively connected to the surface of the inner side (1a, 52a, 201a) of the felt belt.
13. Press section according to either Claim 11 or 12, characterized in that the means comprise a device for producing negative pressure on the inner side (1a, 52a, 201a) of the felt belt.
14. Press section of a papermachine according to one of the preceding claims, characterized in that the press section has at least two press rolls (100, 102) which form a pressing zone (104), at least one press roll (100, 102) being arranged in the interior of an endless felt belt (106, 108) and the endless felt belt (106, 108) having dewatering equipment (110, 112).

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