Title (en)

Sawdust pumping, and processing.

Title (de)

Pumpen und Behandlung von Sägemehl.

Title (fr)

Pompage et traitement de sciure de bois.

Publication

EP 0157279 A1 19851009 (EN)

Application

EP 85103154 A 19850319

Priority

US 59611184 A 19840402

Abstract (en)

A method and apparatus are provided for effecting treatment of sawdust to produce paper pulp in a simplified and effi-cient manner. The sawdust is entrained with liquid so that it forms a slurry having a consistency of between about 10-25%, and preferably between about 15-22% solids. The slurry consistency is maintained generally constant throughout the treatment process. The slurry at that consistency is pumped by a fluidizing, high speed. degassing, centrifugal pump (22). The pumping action alone provides for transport of the slurry to a digester vessel (40, 46). The digester vessel may be an upflow vessel, a hydraulically filled downflow vessel (40), or a superatmospheric vapor phase downflow vessel (40). Kraft pulping may be practiced in the digester, or a sulfite process may be practiced in the digester (46) and the slurry then passed to a refiner to produce a mechanical pulp. Between the pump and the digester the slurry passes through a heating device (30), which may comprise a fluidizing mixer for directly introducing high pressure steam into the slurry, or a pressure diffuser (30) for effecting indirect heating of the slurry.

IPC 1-7

D21C 7/06; D21C 3/22

IPC 8 full level

D21C 3/22 (2006.01); D21C 7/00 (2006.01); D21C 7/06 (2006.01)

CPC (source: EP)

D21C 7/06 (2013.01)

Citation (search report)

• [X] US 3586600 A 19710622 - RICH JOHN P, et al
• [X] FR 569326 A 19240410
• [Y] FR 1226093 A 19600708 - BUSS AG
• [A] US 4370172 A 19830125 - GUEISSAZ CHARLES [FR]
• [AD] US 3475271 A 19691028 - LAAKSO OLIVER A
• [AD] US 4410337 A 19831018 - GULLICHSEN JOHAN [FI], et al

Designated contracting state (EPC)

DE FR SE

DOCDB simple family (publication)

EP 0157279 A1 19851009; EP 0157279 B1 19880810; BR 8501512 A 19851126; CA 1242055 A 19880920; DE 3564300 D1 19880915; FI 78745 B 19890531; FI 78745 C 19890911; FI 851253 A0 19850328; FI 851253 L 19851003; JP H0639755 B2 19940525; JP S60231890 A 19851118

DOCDB simple family (application)

EP 85103154 A 19850319; BR 8501512 A 19850401; CA 477850 A 19850328; DE 3564300 T 19850319; FI 851253 A 19850328; JP 6406785 A 19850329