DE102004022951A1 - Suction roller, at a machine for the production/finishing of a paper or cardboard or tissue web, has perforation channels through the mantle surface with outlets aligned radially in the direction of roller rotation to reduce nose emissions - Google Patents

Abstract

The suction roller, in a machine for the production or finishing of a web (1) of paper or cardboard or tissue, has a perforated roller mantle (3) and an inner suction chamber (5) connected to an underpressure source. The perforations through the mantle are channels to apply suction to the web and permeable blanket (2) passing around it. The perforation channels have an angled outlet at the suction zone (4) of the outer mantle surface, aligned radially in the direction of roller rotation to reduce noise emissions from the air flow.

Description

The The invention relates to a rotatable suction roll with a perforated Roll shell and at least one suction zone, the one, with a Vacuum source connected, position-stable suction chamber within the roll shell is formed, wherein the perforation through consists of the roll shell extending channels.

such Suction rollers have been around for a long time known and become u.a. in machines for manufacturing and / or finishing of fibrous webs, in particular paper, board or tissue webs used.

Around while the effect of the suction zone on the wrapping fibrous web evenly will one possible uniform arrangement of preferably many outer canal mouths sought. This is generally done via a variety of holes of the roll shell, which is seconded in circumferential rows and axial rows are and run into the interior of the suction roll.

When venting the channels after leaving the suction zone, there is a sound emission according to the principle of the hole siren. Since the fundamental frequency of these sound waves is determined by the distance of the channel mouths in the circumferential direction and the rotational speed of the suction roll, is in the DE19963469 proposed to vary the distances and slopes of the channels, so as to obtain a greater variety of frequencies.

The The object of the invention is the noise in such Suction rollers as effectively as possible to diminish.

According to the invention was solved the task by that at least in a predominant Part of the channels at least one ending on the outer lateral surface Channel section extends radially inclined in the direction of rotation.

These Inclination leads because of the relative movement of roll shell and ambient air too a reinforcement of the air flow into the channels in the non-looped area of the suction roll. The fast pressure compensation reduces the noise considerably.

The The result is perfected if at least one of the ends of all the channels ends in the outer surface Channel section extends radially inclined in the direction of rotation.

there is it advantageous with regard to the production of the roll mantle, if at least some, preferably all, channels are entirely radial in the direction of rotation run inclined and / or the channels are designed as holes.

Also about that Can sink at least a portion of the holes on the inner circumferential surface, especially when the type and depth of the countersink varies be changed, the frequency distribution of the sound emission and so the noise level be reduced.

A greater frequency diversity and therefore less noise let yourself also achieve that the holes have different diameters and / or the radial inclination in the direction of rotation the channels is different in size.

to But it may also be advantageous to simplify production if the radial inclination in the direction of rotation at the channels is the same is great.

in the With regard to retrofitting already radially drilled roll shells if it has a reference advantageous if only the each extending in relation to the channel section radially in the direction of rotation inclined. Thus, when changing the cover, the desired inclination of the channel sections be realized easily.

following the invention will be explained in more detail in several embodiments. In the accompanying Drawing shows:

1 a schematic cross section through a suction roll;

2 : a partial cross section through a roll shell 3 with reference 6 and

3 : a partial cross-section through another roll shell 3 ,

According to 1 The suction roll is made of an air-permeable belt 2 and the outer fibrous web 1 entwined. To the fibrous web 1 in the wrap around the tape 2 to suck and so improve the web guide, the suction roll has a suction zone 4 ,

This suction zone 4 is inside the roll mantle 3 from a position-stable suction chamber 5 formed opposite to the rotating roll shell 3 sealed and connected to an external vacuum source.

The roll jacket 3 has a perforation in the form of a plurality of continuous channels 7 , so that the negative pressure of the suction chamber 5 through the perforation and the air-permeable belt 2 on the fibrous web 1 can work.

If the channels during rotation the area of the suction chamber 5 leave, it comes to pressure equalization and thus the inflow of air into the channels 7 , To accelerate this and thus reduce the noise, are the channels 7 or the outer channel sections 8th in the direction of rotation 10 of the roll mantle 3 inclined.

To simplify the production, the channels 7 designed as holes with the same inclination and the same diameter.

In 2 owns the roll shell 3 an outer cover 6 made of plastic. While the hole outside the cover 6 radial, is the reference 6 extending channel section 8th in the direction of rotation 10 inclined. This allows a retrofit in Walzenmänteln 3 whose relation 6 is changed.

At the in 3 shown embodiment is the entire bore in the direction of rotation 10 inclined, which simplifies the production.

To influence the frequency of the sound emission, the holes also have different depths 9 on.

Claims (9)

Rotatable suction roll with a perforated roll shell ( 3 ) and at least one suction zone ( 4 ) connected by a, with a vacuum source, position-stable suction chamber ( 5 ) within the roll shell ( 3 ) is formed, wherein the perforation through the roll shell ( 3 ) running channels ( 7 ), characterized in that at least a majority of the channels ( 7 ) at least one end of the outer circumferential surface channel section ( 8th ) radially in the direction of rotation ( 10 ) inclined. Rotatable suction roll according to claim 1, characterized in that in all channels ( 7 ) at least one end of the outer circumferential surface channel section ( 8th ) radially in the direction of rotation ( 10 ) inclined. Rotatable suction roll according to claim 1 or 2, characterized in that at least some, preferably all channels ( 7 ) completely radially in the direction of rotation ( 10 ) inclined. Rotatable suction roll according to one of the preceding claims, characterized in that the channels ( 7 ) are designed as holes. Rotatable suction roll according to claim 4, characterized that at least part of the bores is countersunk on the inner circumferential surface. Rotatable suction roll according to claim 4 or 5, characterized characterized in that the holes have different diameters exhibit. Rotatable suction roll according to one of the preceding claims, characterized in that the radial inclination in the direction of rotation ( 10 ) at the channels ( 7 ) is different in size. Rotatable suction roll according to one of claims 1 to 6, characterized in that the radial inclination in the direction of rotation ( 10 ) at the channels ( 7 ) is the same size. Rotatable suction roll according to one of the preceding claims, characterized in that the roll shell ( 3 ) a reference ( 6 ) and preferably only in each case in relation ( 6 ) extending channel section ( 8th ) radially in the direction of rotation ( 10 ) inclined.