At the end of this module, you will be able to:
- Describe the purpose of carrier ropes on a paper machine
- Identify the major components of a safe and efficient carrier rope system
- Identify and describe the equipment in a carrier rope system
- Describe a typical rope path through a dryer section
- Describe the design considerations for sheaves, including layout, alignment, wear, and material
- Describe the major factors in rope selection
- State the importance of proper rope tension
The following key questions are answered in this module:
What is a "dog leg" in a carrier rope system?
A "dog leg" release transfer refers to a rope transfer sheave setup that facilitates the dropping of loose tails and broke after a transfer point during threading. This improves threading and carrier rope life.
If a carrier rope needs to change direction on a sheave, how should the sheave be set up?
The rope should enter the sheave square to the groove and exit on the required angle. The straight-on entry angle helps keep wads and broke from rolling the rope out of the sheave. The exit angle should be within the groove profile to minimize rope abrasion on the sheave edges.
What is the most common cause of premature rope failures?
Poor sheave condition is the most common cause of premature rope failures. Secondary grooves worn in the root of the sheave will abrade the length of the rope, and especially hammer and wear the splice (which tends to be slightly bigger around than the rope) as it passes through.
Why is rope tension reduced after threading?
Rope tension should be reduced after threading to allow the ropes to recover from the higher threading tension and help them maintain their natural elasticity. It also helps minimize rope wear by reducing the effects of abrasion.
Why are carrier ropes sometimes coated or treated?
Size press and coater sections tend to use coated or treated rope to combat the effects of the chemicals present in these sections.
Below is a transcript of the video sample provided for this module:
A properly operating rope tensioner will work with the ropes to keep them tight but not allow them to stretch as a result of wads passing through the system. The sliding carriages in a tensioner are designed to move to adjust for wads caught in the ropes, normal elongation and shrinkage of the ropes as a result of the combination of wear, moisture, and heat. Running the ropes at a constant high tension negatively affects threading by reducing the diameter of the ropes which may result in the ropes failing in the open draws. Additionally, the ropes built-in elasticity and ability to recover from wads and irregularities in the system will be reduced. Excessive tension on the ropes at any time will lead to premature failure of the ropes, shivs, and shiv bearings.
Use the additional resources and links below to learn more about this topic: