Bump Response

Factors that affect the height and CD width of the bump response are important parameters for designing a steam box.

 Bump Response-Fourdrinier Z-Box, Heavy Basis  weight Liner - Honeywell QCS, 4 Bumps of 70 % up and down

Bump Response-Fourdrinier Z-Box, Heavy Basis  weight Liner - Honeywell QCS, 4 Bumps of 70 % up and down

  • Steam velocity
  • Volume of steam
  • Dwell time of steam against the web
  • Vacuum applied to steam and web

The Transphase Z-Box Steam Profiler is a 100% profiling steam box. The QCS has 100% control of the CD range of the actuator.

  • Uniform application of any amount of steam will heat cold areas faster than warm areas. Leading edge steam preheats the whole sheet reducing the CD control range. Manufactures have been known to tell customers to shut it off to increase performance.
 Bump Response, Fourdrinier Z-Box- Medium, ABB QCS

Bump Response, Fourdrinier Z-Box- Medium, ABB QCS

  • If we blow high velocity steam against the direction of the sheet, we will disrupt the steam being condensed in the CD zones, spreading it in the CD direction. This results in a lower bump response.

Steam velocity is one of the most important parameters to control in order to improve CD response. Most manufactures talk about high velocity steam being used to penetrate the web.

Transphase approach is different. We want to match the steam velocity to the web velocity and the available vacuum and vacuum box cover. We employ the Z plate design to hold the low, matched steam flow against the web and allow the vacuum to draw the steam into the web. We work with a High Vac and Super High Vac  manufacturer to insure the steam diffuser design is correct for the vacuum box design.