Sheet Takeoff System Combines Features Of Inclined And Vertical Stacks

Sheet Takeoff System Combines Features Of Inclined And Vertical Stacks

The Trident Series J-Stack sheet takeoff system from Processing Technologies (PTi) is said to combine the benefits of 45-deg inclined stacks (but  with 25% greater roll wrap) with those of up-stacks (greater space under the conveyor for water system component location and access, as well as gravity-assisted web transport, which is said to minimize orientation due to conveyance tension control.)

The unit, which is designed for use with the manufacturer's Trident Series extruders, has 450 deg of web wrap, as opposed to the 360 deg commonly found with vertical configurations. This is claimed to yield 25% greater utilization of roll cooling for high throughput systems and thick sheet systems that require stabilization of web core temperatures for dimensional control and high surface quality effects.

According to PTi, most stacks only use a small percentage of the roll's actual surface area during processing. A fully inclined 45-deg stack does not offer the amount of roll wrap that is provided by the J-Stack, because they are essentially a vertical stand that is at a 45-deg attitude.

By contrast, the J-Stack has a 45-deg approach with a vertical completion. This is said to be beneficial when processing low melt strength materials because it allows the die extrudate to enter the primary roll nip point at closer proximity than that of a vertical arrangement.

In addition, the vertical completion balances the web's roll exposure symmetrically (i.e., the amount of wrap both sides of the web are in contact with before exiting the roll stand). This balances the process for thermal and dimensional stabilization.

Other features include quick roll change-outs with split style arms to facilitate roll removal; direct- or chain-drives, depending on what the process calls for; in-line lamination and masking for web protection or decorative appearances; levant or other pattern rolls for an embossed appearance; pneumatic or hydraulic roll actuation, depending on requirements; and PTi's Auto-Gap hydraulic roll gap modulation for automatic set-up and roll gap maintenance.

Please contact the manufacturer for pricing information (use the Key Contact Directory on p 38).

Processing Technologies, Inc.
St. Charles, IL