What is Suction Press Roll and Suction Couch Roll Seals?
Rubber Air Tube for Paper Machine
Air tube and sealing strips are common sealing components in the modern papermaking industry. They are important devices for improving dewatering efficiency and paper web forming quality. Air tubes achieve roller surface pressure regulation and water absorption uniformity through stable air pressure support, so as to make the paper web run more stably.
The suction press roll and suction couch roll seals parts is mainly combined with air tube and sealing strips. The material of sealing strips is UHMWPE material and graphite material. The UHMWPE sealing strips are suitable for low speed paper machine. The graphite material sealing strips have features of wear resistance, self-lubricating, and do not deform during use. It's suitable for 200-1800m/min paper machine speed.
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The Working Principle of Suction Roll Seals
The seals principle of suction roll is enlarging the vacuum degree and lock the seals. It shows on below two points:
The sealing strips is used for withstand the suction roll inner shell, and get higher vacuum in the vacuum zone by air tube load.
When the sealing strips widthstand the roll shell, it's locked by the air tube. It will reduce the wear of sealing strips and roll shell by locking the sealing strips, and reduce the noise and transmission load.
The Advanatges of Graphite Sealing Strips
Due to high pure of graphite, when the roll is rotating, static electricity of the same polarity is generated between the two.Under the action of mutual repulsion, a gap is formed, and at the same time, water sprayed out through the spray pipe or vacuum sucked in quickly forms a water ring between the inner wall of the roller body and the graphite sealing strip. The water ring also forms a water layer when passing through the gap, which is called a water sealing layer. And the graphite material is heat resistance, high density and high smoothness, under the strong suction effect of vacuum, when the water layer passes through the gap, a water sealing layer is formed to tightly maintain and produce high sealing degree. Therefore, the characteristics of graphite seals are incomparable to other materials.
Comparison of Graphite Sealing Strips and Sealing Strips Made of Different Materials
For example, Using UHMWPE as a sealing strip, due to its lack of lubrication, high temperature resistance, and static electricity, it cannot form a water ring sealing layer. Under high-speed operation and tight sealing with the tire pressure top, it quickly adheres to the inner wall of the roller body, quickly deforms and increases the friction coefficient. It also damages the inner wall of the roller body, destroys the sealing performance, has a high repair rate, and increases maintenance costs.
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How to Check The Sealing Strips Still Have Seals Function?
Check the axial seal wear and cracks of the suction roll sealing strip, whether the sealing joint is damaged and clean, and whether the sealing strip clamp is clean;
Replace the damaged sealing strip. If the thickness is damaged by more than 10mm, a new sealing strip needs to be replaced;
The suction roll suction box has a narrow axial seal at the inlet and a wide axial seal at the outlet;
Check the longitudinal clearance of the axial seal in the sealing strip;
Check the edge operation, edge seal cleanliness, and operation of loading air tubes.
