Vacuum Tension Rolls (VTR) — also known as Vacuum Pull Rolls (VPR) — are hollow rollers with perforated outer shells through which a vacuum is pulled. The VTR stationary centertube is outfitted with internal seals or deckles to create a confined vacuum zone. The pressure differential between the internal vacuum zone and external atmosphere creates a holding force, working with the effect of friction between the roll surface and the web running over it. A drive pulley or journal connected to the outer VTR shell holds back or pulls the web to alter or isolate web tension.
Vacuum tension rolls from PRS feature durable designs that web coaters and converters can use to dial in precise tension levels for optimal performance.
- Screen Options: Allow for protection of the web material. Fine mesh is less likely to damage delicate web materials. Seamless screens are available for the most delicate operations
- Width Adjustments: For variable web widths, choose from mechanically adjusted or pneumatically adjusted vacuum zone width control. Depending on the application, each option offers advantages and disadvantages:
- Mechanical adjustment advantages: Infinitely adjustable within the set range. Position indicator shows width setting
- Mechanical adjustment disadvantages: Moving parts can get stuck (depending on environmental conditions).
- Pneumatic adjustment advantages: User-friendly, well suited for automation. Tighter seal clearances produce a more efficient performance
- Pneumatic adjustment disadvantages: Not infinitely adjustable
- Surface Treatments:
- Electroless Nickel Plated: Corrosion-resistant smooth finish
- Rubber Covered: Compliant surface has the highest traction/grip
- Plasma Coated: Enhanced traction/grip in addition to high-release coating
- Fine Mesh Screens: Non-Marking, best for thin or sensitive webs
- Mechanically Engraved Textured with Micro Grooves: Added traction/grip, enhanced air exhaustion
Vacuum Tension Rolls (VTR) offer single sided contact with sensitive substrates that can eliminate scratching or other potential damages. Removal of the air boundary layer improves constant tension control in all zones and enhances the ability to process lightweight materials at minimal wrap angles.
Questions? Tough challenge? Need a second opinion? The PRS experts are here to guide you to your next-level engraved or precision roll solution. Set up a consultation today!