Lift Sling Rigging Co., Ltd manufacture paper machine rope tailing,paper machine rope threading.

Paper Machine Rope Threading System is an essential auxiliary mechanism designed for the automatic threading of a paper web from the press section, through the drying section, and onto the reel of the paper machine. Its primary function is to guide a narrow leader strip (or "tail") of paper safely and efficiently through various machine sections, especially during startup or after a web break.

This system serves as the connecting link between all rollers of varying sizes in sections such as sizing, coating, post-drying, and the reel. It is responsible for pulling the narrow paper web from one roller to another, ensuring continuous and stable production.

Key Components & Design

A standard rope threading system consists of a set of pulleys, rope stretchers, and, if necessary, a rope drive. Auxiliary chutes and air pipes with nozzles can be installed at transfer points to assist in guiding the paper.

Rope Pulleys: The dimensions of the pulleys (diameter, width, groove depth) depend on the machine speed and the basis weight of the paper.

Leading Pulleys: Used to form rope threading wedges at transfer points, featuring a lower depth of groove.

Guiding Pulleys: Used for guiding threading ropes through the machine, featuring a higher depth of groove and available in single or double modifications.

Rope Drive: The rope drive is employed when the threading ropes do not pass through drying cylinders or when the web contact is insufficient to prevent slippage. The speed of the electric motor is controlled by a frequency converter and is typically derived from the speed of the nearest suitable roll.

Rope Stretching System: Designed to stretch the threading ropes individually, this system ensures proper tension for effective paper handling.

Pneumatic Rope Stretching: Controlled by a pneumatic control board, this allows continuous adjustment and a quadruple stroke of the cylinders. The maximum stroke is signaled by magnetic position sensors.

Mechanical Rope Stretching: A system of weights provides vertical stretching with a doubled stroke, offered upon request.

Threading Rope (Carrier Rope)

The carrier rope is a high-temperature, quality-impregnated filament nylon rope, often made from DuPont fiber or similar high-performance materials. It must be wear-resistant and heat-resistant (capable of withstanding 180-280°C).

Construction: Many modern ropes feature a unique hollow braided construction that resists flattening under normal operating tension, enhancing threading efficiency and ease of splicing. For extra resistance to elongation, options in filament polyester are available for wet conditions.

Performance: The rope's unique impregnation gives greater protection to the fibers and provides an excellent surface for gripping the paper tail.

Selection:

Two-Rope System (Dual Rope): Typically used for paper grades with a basis weight of 40–120 g/m².

Three-Rope System (Triple Rope): Used for heavier paper grades over 120 g/m².

Diameter & Elongation: For machine speeds of 300–800 m/min, a diameter of 12–15 mm is sufficient. For speeds above 800 m/min, a thicker rope is recommended. The elongation rate is typically 3%–5%.

How It Works: The Threading Process

The threading process involves guiding the paper web tail through the machine using the rope system:

Tail Separation: A leader strip (tail) is separated from the edge of the paper web, typically in the dryer section.

Rope Nip: The leader strip is directed into a "rope nip," which is the convergence point between a pair of ropes. This nip is formed by the ropes running in a common loop.

Transfer: The leader strip is guided between the ropes and carried through the machine sections. In some designs, air blowing is used to transfer the leader strip from the drying wire into the rope gap.

Completion: The ropes carry the tail over drying cylinders and through finishing devices (like size presses or coaters) until it reaches the reel.

Applications & Advantages

The rope threading system is critical for paper machines manufacturing kraft paper, printing paper, and other grades. Key benefits include:

High Efficiency: Automates the threading process, reducing downtime during startup or after breaks.

Versatility: Can be customized for different paper grades and machine speeds.

Reliability: The use of high-quality nylon carrier ropes ensures a stable grip and long service life, even at high speeds (up to 800 m/min or more).

Precision: Pneumatic stretching systems allow for precise and continuous tension adjustment, ensuring stable operation across all sections