Winder air systems
For controlling and reducing emissions and creating a good indoor air quality Valmet has developed a 3-stage approach. The primary stage includes capture of noise, dust, gaseous compounds, moisture and heat at the source. Emissions are captured by local exhausts, air curtains, dust and mist collectors immediately when formed and are transported away without fouling the surrounding air.
Ventilation equipment at winder is needed for
- Dust control
- Trim conveying
- Loose paper conveying
Main benefits of the Winder Air system
- Reduce emissions to air
- Improves working conditions around the winder
|Reduces the amount of inhalable paper dust|
Dust coming off the paper causes problems in a printing machine and impairs the working environment at the winder. Together OnSheet and OffSheet dust removal systems form an effective method for solving such problems at the winder.
OnSheet dust removal
The heart of the OnSheet dust removal system is patented WCH cleaning head (Web Cleaning High Velocity). A high velocity air knife of the whole sheet width and at flow rate of even 200 m/s is directed on the paper surface. The particles detached from the surface are taken into the ventilation system for treatment.
OffSheet dust removal
OffSheet dust removal system removes dust from the winder surroundings. Correctly located exhaust points can significantly decrease the need for cleaning the winder or pulp dryer cutter layboy and improve the air quality of the working areas.
Humidity control at the winder
Ventilation at the winder is used to prevent the paper from drying. The paper shrinks when it dries, which leads to runnability problems at the winders.
Humidification of the winder area
Paper shrinking is affected by controlling the air properties around the paper. The humidified air is blown to the slitting area, which is critical to shrinkage. There the humidity can be effectively controlled. When humidity is optimal, the sheet does not shrink at the knives, hence preventing any problems with runnability.
Vacuum trim conveying system
- Reliable trim handling system with low relative energy consumption.
- Based on the use of vacuum
- Directly connected to the paper machine broke handling facilities.
- Proven to be the most convenient trim handling system for modern high-speed winders.
Operating principle: Trims are sucked from the winder slitter area to trim chutes by the negative pressure created by the fan. The air flow conveys the trims along the conveyor ducts to the trim conveying cyclone where trims are separated from the air flow by water and stock showers and centrifugal force.
Loose paper conveying
- Handles pieces of paper from the winder area to the pulper in a comfortable way
- Consists of feeding hatches, ducts and a fan.
Operating principle: The hatch located in the winder area is opened by an operating switch which starts the loose paper conveyor fan at the same time. Pieces of paper are fed to the open hatch and the system conveys them through ducts into the pulper. The system is also applicable for other parts of paper and board manufacturing process, eg. calenders and reels.