FI115310B - Creator for a paper or cardboard machine - Google Patents

Description

115310

Paper or board machine scraper Schaber för en pappers- eller cardboard mask 5

The present invention relates to paper and board machines. More particularly, the present invention relates to a scraper according to the preamble of claim 1.

The rotary roll, drying cylinder or winding cylinder 10 of a paper or board machine can be provided with a scraper. The purpose of the scraper is to prevent the web from wrapping around the roll or cylinder during web break and to facilitate threading of the web. The purpose of the scraper is also to keep the surface of the roll or cylinder clean. There are two different types of scrapers: a tactile scraper with a scraper blade extending across the entire width of the roll or cylinder against an outer surface of 15 rolls or a cylinder, blowing into the gap between the tip of the scraper blade and the outside of the roll from the back of the scraper blade to prevent the web from rolling with the roll or cylinder. The present ·· 20 invention relates to a tactile formulator, hereinafter referred to as:.

*. Touch jets known in the art include: following *. disadvantages: insufficient grip on the blade, uneven grip, excessive pressure to increase grip, resulting in increased cylinder or roll torque. If the grip of the stencil blade is insufficient or uneven, it * i * '· ·.' may result in the web being trapped between the blade and the cylinder or roll. This: *, \ situation is undesirable and device malfunction. Contact of the web with the scraper blade ':' and between the cylinder or roller may break the scraper blade. In addition, the web will not be triggered in 30 desired and controlled ways.

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Prior art solutions cannot control the web flowing from cylinder or roll to pulper or to a wreck conveyor.

Some drawbacks of the prior art solutions also include that the abrasive contact scrapers wear, brake the rotating cylinder and load the cylinder drive. In addition, as a result of wear, scrapers need to be replaced regularly, resulting in short production stoppages.

Another problem with prior art tactile patterning solutions 10 is that when the web collides with the scraper blade blade, the web may bend the blade backward so that the blade scrapes the worn blade socket, allowing the blade tip to open between the cylinder blade and causing the web to be deflected around the cylinder, in which case the web must be cut and re-routed past this point to clarify the situation.

It is an object of the invention to provide a scheme in which the problems and drawbacks of prior art solutions are eliminated or at least minimized.

In order to achieve the foregoing and further objects, the paper or board machine schema according to the invention is substantially * characterized in what is set forth in the characterizing part of claim 1.

. In accordance with the invention, a contact blade is provided with a * 'down blowing device for removing and drawing the web with a downward jet of air from the scraper, and the jet removes the web from the diatomaceous earth and' * prevents the web from colliding with the scraper blade. The pull-down blow in accordance with the invention is carried out with substantially the entire width of the web.

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Thus, according to the invention, the scraper comprises a substantially web-wide pull-down blowing function which is intended to keep the web out of the scraper and to direct the web to a pulper or scrap conveyor.

5 The web retraction blow is used to pull the web off the surface of the cylinder or roll as soon as it has reached and passed the stencil blade and tightens the web between the cylinder surface and the web retraction nozzle. The pull-down blasting is used when the web is driven from the cylinder or roll to the pulper or the wreck conveyor to provide greater reliability for controlled wrecking of the wreck 10 and to prevent the web from wrapping around the roll or cylinder. The scraper itself will be responsible for scraping only when the end of the web is bypassed. Later, the scratches have only a securing role alongside the drawdown.

The down blowing device consists of a blowing nozzle which is substantially as long as the maximum track width, and the supply of air to the blowing nozzle is advantageous both from the service and the operating side of the machine.

According to the invention, when the end of the web passes the scraper and starts to run on the pulper: or on the wreck conveyor, the end of the web is immediately controlled by a draw blow

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: 20 by means of which pulls the end of the web off the surface of the cylinder or roll and tightens it between the surface of the cylinder and the blow nozzle. This keeps the web under control all the time when the paper is fed to the pulper or to the scrap conveyor.

According to a preferred further feature, a slit orifice nozzle is used as the downflow nozzle.

. 25 Compressed air blow-down with approx. 7 bar and nozzle gap 1-6 mm, preferably • ·. ·· 1.5-3 mm.

• · * »» I »•» '! In accordance with another preferred feature,> 9,411,510 is used as the blow-off nozzle

According to a further advantageous feature of the invention, the blowing force can be profiled in the transverse direction, i.e. in the width direction of the web.

Preferably, the scraper and blower control devices of the invention are coupled to a paper or board machine breaker automation, whereby in the event of a web break, the blowing operation is automatically activated and, if desired, the scraper timing can be switched to the thread blowing sequence. The scraper control device and the blower device control device are coupled and there is a time delay between the control and the blower device and the blower device. In addition, the devices 10 can be automatically switched off after clearing the web break.

According to the invention, the pull-down blowing provided by the device underneath the scraper provides control over the web passage of the web down to the pulper, since in down-blow blast the downflow web is driven directly to the pulper or scrap conveyor without risk of falling through the scraper.

The scraper according to the invention is preferably used in connection with a winding cylinder, but it is also applicable to drying cylinders and at suitable locations in the press, as well as in other roller / cylinder roll downs. The scraper according to the invention can be used at least up to 1200 m / min and up to 2500 m / min.

In the following, the invention will be described in more detail with reference to the figures in the accompanying drawing, which are not intended to be the details, however. 25 in no way narrowly restricts.

Fig. 1 schematically illustrates a prior art situation in which the web • 1 · * 'j is just about to collide with a scraper blade.

Fig. 2 schematically illustrates a prior art situation where:. 1 ·: The scraper blade removes the web from the cylinder.

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Fig. 3 schematically illustrates a situation in which, in accordance with the invention, the web is pulled out by means of a retraction blast to remove the scraper blade steel.

In Figures 1-3, like reference numerals are used for like parts.

Fig. 1 shows a scraper 20 arranged in connection with a roll / cylinder 10 with a scraper blade 21 which removes the web W from the surface of the cylinder 10. The direction of rotation of the cylinder 10 is denoted by the reference S. As shown in the prior art solution, the web W is just about to collide with the blade 21 of the scraper 20.

In the situation of Fig. 2, in the prior art applications, after the situation of Fig. 1, the web W is removed by a scraper blade 21 of the scraper 20 from the surface of the cylinder 10. The web W detaches from the surface of the cylinder 10 and begins to fold after the blade 21, dropping into the pulper. Then, at a given force and frequency, the web W hits the blade 21 of the scraper 20, whereupon the blade 21 of the scraper 20 becomes deflected, which causes the angle of the blade 20 to change, i.e. the angle between the blade 21 and the cylinder 10. allowing the web W to pass along the surface of the cylinder 10 between the blade 21 and the * () cylinder 10, causing the web to deflect around the cylinder 10,! ! whereby the web must be cut, the roll / barrel 10 cleaned, possibly even / stopped and the web re-passed past that point. Stopping large rotating inertia masses requires unnecessarily expensive production time, e.g.

; 25 100 - 200 euros / minute.

Fig. 3 shows an arrangement according to the invention in which the scraper 20 is connected! a device 25 for pull-down blowing PA to control the passage of web W is provided. straight down towards the pulper so that the web W does not hit the stencil blade 21 of the stencil 20 or the t 20, but remains loose and guided to the pulper.

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The control device 31 of the scraper 20 and the control device 32 of the lower blowing device 25 are preferably coupled together with the paper or board machine break and thread control system 30 so that it can be adapted to operate automatically in the event of a break and / or head export.

5, 31.32 has a time delay and possibly also a time duration in both.

The nozzle slot 26 of the blowing device 25 is preferably a slot nozzle which extends over the entire width of the web and the blow slot is 1-6 mm. The down blowing device 25 10 provides a pull down blowing PA, whereby the air flow it requires is pressurized pressure, preferably 5-7 bar.

The invention has been described above only with reference to a preferred embodiment thereof, the details of which, however, are not intended to be narrowly limited.

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Claims (9)

115310 A paper or board machine scraper fitted to a roll or cylinder (10) of a paper or board machine to clean the surface 5 of the roll or cylinder (10), the scraper (20) comprising a scraper blade (21) to prevent the web (W) from rotating. or around the cylinder (10) during a web break and to facilitate threading of the web (W), wherein a down blowing device (25) is provided in connection with the scraper (20) to prevent blow (PA) from colliding with the scraper (20) Past the scraper (20), characterized in that the scraper (20) of the scraper (20) is arranged to provide a pull-out blow (PA) of substantially the entire web (W), by which the web (W) is detached and drawn from the scraper (20) that the blowing nozzle (26) of the down blowing device (25) is a slot nozzle. Scraper according to Claim 1, characterized in that the down-blowing device (25) is arranged to provide a down-blowing (PA) having an air pressure of 5 to 7 bar. A scraper according to claim 1 or 2, characterized in that. · * The nozzle gap of the slit nozzle of the 20 lower blowing devices (25) is 1-12 mm, preferably 2-10 mm. Scraper according to one of Claims 1 to 3, characterized in that the draw-down blow (PA) is arranged to be effected by compressed air. 25 I Scraper according to one of Claims 1 to 4, characterized in that '. the control device (31) for the scraper (20) and the control device (32) for the lower blower device (25) are connected to the cut and thread control system (30) of the paper and board machine. ' to operate automatically in the event of interruptions and taking into account the threading of the web. : ·; 30, 115310 Scraper according to one of Claims 1 to 5, characterized in that the control means (31,32) of the scraper (20) and the lower blowing device (25) are connected. Scraper according to claim 6, characterized in that there is a time delay between the control of the control means (31,32) between the scraper (20) and the lower blowing device (25). Scraper according to Claim 6 or 7, characterized in that the controls of the control means (31,32) have a time duration between the scraper (20) and the downflow device (25). Scraper according to one of Claims 1 to 8, characterized in that the blowing force provided by the down blowing device (25) is to be profiled in the transverse direction 15. 115310