Waste paper treatment is of great significance in the paper industry. The collected and sorted waste paper is fiberized in pulpers using large amounts of water with the addition of chemicals and is sorted into slightly and heavily contaminated fractions.
In the de-inking process, the printing ink is removed by means of chemicals and mechanical forces and is skimmed as foam from the surface in the subsequent flotation.
The risk of dry running for the mechanical seal is especially great for the machines used in the flotation process. The seals in the coarse screening are subjected to intense stress due to the contaminations inclined to plaiting. Know-how and experience in the selection of seals and materials are requirements in order to ensure optimal and trouble-free operation.
The shafts of bleaching agent pumps, MC pumps, dispersers, slurry pumps, sorters, pulpers and fiberizers are successfully equipped with EagleBurgmann single and double seals of the LP, M7N, M74, HR and Cartex-DN series. Thermoflon and Buramex type compression packings reliably seal bleaching agent pumps and separators in the waste paper treatment process.
Waste Paper Treatment Process
Successful Mechanical Seals for Waste Paper Treatment Facilities
At UPM Kymmene Shotton in England, nine Voith pressure screens in waste paper treatment are being used successfully with EagleBurgmann HR-D type double cartridge seals. Medium to be sealed: Pulp fibers 1.5 … 4 % abs. dry and water, p = 8 bar (116 PSI), t = max. 40 °C (104 °F).
In the waste paper treatment at Palm in Wörth, Germany, four TL200/TL300 type Metso Screens with LP-D-ST-D15/130-DE were retrofitted to non-flow operation and have been running in continuous operation (24 hrs./day) since 2004. Medium: Pulp 3 % abs. dry and water, t = 50 °C (122 °F), p3 = 4 bar (58 PSI), n = 800 min-1.
At Stora Enso Maxau, Germany, Voith slot sorters in a waste paper treatment plant for the production of standard and upgraded newsprint paper are sealed with EagleBurgmann HR10 type seals (“dead-end”). Flushing with circuit water (return water) is used only when the medium has a too high solids content. Face material combination SiC/SiC, shaft diameter d1 = 46 … 130 mm (1.81” … 5.12”), p1 = 1 bar (15 PSI), t = 60 °C (140 °F), n = 980 min-1, medium: Paper pulp (0.2 … 5 % abs. dry). The Palm Paper Ltd. paper mill produces newsprint for national and international newspapers. Production is based solely on waste paper pulp.
A TotalSealCare service agreement having a duration of several years includes servicing of all installed mechanical seals for pulp pumps, mixers and various pressure screens. Additional contractually agreed services are on-site presence during start-ups, troubleshooting and providing seal-related schooling and training courses for plant personnel.