1. Common factors that affect the type of tail feeding system used are:
2. No one piece of tail feeding technology can be applied throughout a paper machine, a combination of measures which can deal with the unique characteristics of the machine and product at each site will normally be required. Types of tail feeding technology are described in paras 3-7 below.
3. This is the system of using ropes and sheaves (pulleys). They tend to be lower in initial cost and easy to integrate as part of a combined system. They can cope with vertical paths. However they pose high demands for maintenance with the associated risk of unplanned downtime if this is not carried out. In particular failure to maintain alignment can lead to rope loss. Rope diameter is important, too small and it can result in speed mismatch. Rope surface speed is critical as is the depth of the groove in the pulley.
4. These use compressed air to direct the tail over a tray. They are a relatively low cost option for machines manufacturing one grade of product at one speed. If they are used at a machine where the product varies then they need expert adjustment and there are speed limitations. They are best used to direct the tail over short distances in combination with other technology. The use of compressed are means that the operating costs are high. Crews would require more detailed training where adjustment was necessary.
5. These use compressed air to direct the tail along a tube. They are often an option used for tissue or light grade papers. They carry the same high operating cost as air trays, in terms of both energy usage and operator training. They usually require a smaller tail than the norm of between 75-100 mm.
6. These operate by using compressed air to create a vacuum. They can deal with a wide range of grades and speeds and can be automatically adjusted. They can operate within tight space limitations and cope with vertical/inverted paths. The initial and operating cost is higher than other systems, and there are high maintenance requirements for the fans and ducting.
7. These are a range of measures, including airguns, foil technology and vacuum rolls. They can involve high initial and operating cost. There are particular developments underway in foil technology which can deal with changes in tail width, eliminate the need for separate fans or ducts and can combine blowers and vacuum.
8. In all cases there will also be a need for tail cutters or choppers, using water jet technology or rippers.
