Rising energy prices and growing environmental awareness have led to a sales boom for MAN’s vacuum systems in the tissue segment over the last 10 years. Sanitary paper manufacturers appreciate the many benefits of blower technology compared with traditional vacuum generation using water ring pumps.

Vacuum systems play a central role in the paper production process. They are deployed at the point in the production process at which the installation dewaters the paper using vacuum. MAN’s one-stage RT is now very widely used for new tissue machine installations.

There is also a fast-growing trend towards conversion, with the old vacuum systems previously installed in existing tissue machines being replaced with RT blowers. The RT 56 is most popular for the narrow 2.8 m tissue machines with production speeds of up to 2200 m/min, while the larger RT 71 is the preferred model for 5.6 m tissue machines.

 

Automatic airflow regulation.
Automatic airflow regulation.

 

MAN covers all the usual manufacturing processes: conventional crescent former, TAD (through-air drying), ATMOS (Advanced Tissue Molding System) and Advantage NTT technology for producing sanitary paper.

Resource-efficient and cost-saving dewatering

The sustained success of the single-stage TURBAIR® is based on a number of factors:

♦ Compared with traditional water ring pumps, a TURBAIR® blower from the RT series requires only about 45-55% of the absorbed power.

♦ The volume flow changes depending on the age of the felt: the air volume requirement is controlled automatically by diffusor blades regulation. The aim is to achieve consistent dewatering over the felt.

♦ The RT has a frequency-controlled drive: the vacuum may be adjusted to a wide range of tissue weights and types.

♦ TURBAIR® blowers do not require seal water, so no fresh water and no cooling tower is required.

♦ Vacuum blowers have no wearing parts, making them dependable and maintenance-friendly.

♦ The base frame for the RT series bolts straight to the floor, resulting in a very compact design.

♦ The efficiency of the water separation process has seen considerable improvement in recent years, making it possible to extend the cleaning intervals for the concrete or steel separator.

♦ The blower exhaust air can be sent to a heat exchanger (from single- to three-stage), which discharges the blower at a temperature of 120-130°C and thereby recovers up to 70% of the absorbed energy.

 

Huge cost savings can be made on paper dewatering

 

Type RT TURBAIR® vacuum blower.
Type RT TURBAIR® vacuum blower.

“In combination, these benefits result in a simple return-on-investment calculation for our customers: the amortization time of a TURBAIR® system of this kind, installed in an existing paper production mill, is less than two years,” says Manfred Dobler, Head of Paper Industry at MAN Diesel & Turbo.

Following here a small selection of references for new tissue installations: SCA in Germany; WEPA in Germany, France and Poland; FRIPA in Germany; HAYAT in Turkey, Russia and Egypt; Ipek Kagit in Turkey; METSÄ-Tissue in Poland; First Quality Tissue in the USA; Sofidel in Poland and USA and many more. A few references where TURBAIR® blowers replaced the existing vacuum system: Kimberly-Clark in Spain and the USA; Sofidel in Belgium; LC Paper in Spain; Georgia-Pacific in Spain and many more.

A large number of satisfied sanitary paper producers confirm the successful use of TURBAIR® blowers in tissue manufacture and show that huge cost savings can be made on paper dewatering.