Valmet Paper Machinery Inc.

Lauri Suvanto

Juha Kivimaa

Martti Hirsimaki

Jouko Villa

The invention relates to a method and device in the crawling operation of a press felt in a paper machine. The press felt is passed as a closed felt loop through a nip defined between a center roll and a press roll in a press section of the paper machine. The felt is driven during the running operation of the paper machine by means of a nip drive between the center roll and the press roll of the press. When the paper machine is not operating, and the nip between the center roll and the press roll in the paper machine is open, the felt is moved, so as to moisten the new felt, by means of the crawling drive by rotating the drive roll. An axle of the drive roll is permanently connected to a drive rim. During the crawling operation, a drive wheel of a hydraulic device is brought into engagement with the drive rim. When the crawling drive of the felt is not in operation, the drive roll is switched to the free revolving position by shifting the drive wheel of the hydraulic device apart from the drive rim. The drive wheel is operationally connected to the drive rim.

Method and device in a crawling operation of a press felt in a paper

The invention concerns a method and a device for removing water out of the perforations in a suction roll wherein a doctor blade is brought into contact with the face of the suction roll. The doctor blade is mounted with its slat face in such an angular position in relation to the face of the suction roll that the angle between the face plane of the doctor blade and the tangential direction of the face of the suction roll, when the tangent is drawn at the contact point between the tip of the doctor blade and the face of the suction roll, is from about 2.degree. to about 10.degree.. In the method, water is removed by means of the inlet-side surface plane of the doctor blade, the inlet side being seen in the sense of rotation of the suction roll, and the water is allowed to flow smoothly over the doctor blade out of contact with the construction. According to the invention, water may be additionally removed by means of a suction effect out of the area between the slat face of the doctor blade and the suction roll, negative pressure being produced in the space. The negative pressure produces flow of water out of the perforations or grooves in the suction roll.

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Jyvaskyla, Finland

Lauri Suvanto