Web Tension Control with Vacuum Tension RollsVacuum tension rolls and belts provide web tension control by generating a web force against the roll or belt that is independent of the web tension differential (Tension In and Tension Out). The discussion that follows is based on vacuum rolls, but generally applies to vacuum belts as well. Two things happen when the vacuum is applied to the roll. First, the vacuum under the wrap angle creates a pressure difference between the vacuum level and atmospheric conditions. This pressure difference forces the web against the roll and...
Vacuum Roll CharacteristicsVacuum rolls and belts have a number of characteristics that are potentially useful to converters. What benefits are derived depends on the application, which will be addressed later. A summary list of characteristics follows.
- Single Side Contact - A very popular feature of vacuum rolls is the ability to control tension in a web while touching only one side.
- No nip is used, so a potential source of injuries is eliminated.
- Vacuum rolls can transport a wet web, coated but not yet dried or cured, without touching the coated side.
- Once the coating...
The characteristics listed in Part 3: Five Benefits of Vacuum Rolls lead to a wide variety of applications for vacuum rolls and belts for the converting industry. A vacuum roll may replace a standard driven roll to do the same job better, or its unique characteristics may be used to alter and improve a process. For an idea of how some converters have applied vacuum rolls to their advantage, consider the following: [caption id="attachment_2727" align="alignright" width="200"] Read more