Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/02—Pretreatment of the raw materials by chemical or physical means
  • D21B1/023—Cleaning wood chips or other raw materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
  • B03B5/62—Washing granular, powdered or lumpy materials; Wet separating by hydraulic classifiers, e.g. of launder, tank, spiral or helical chute concentrator type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
  • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
  • B03B5/62—Washing granular, powdered or lumpy materials; Wet separating by hydraulic classifiers, e.g. of launder, tank, spiral or helical chute concentrator type
  • B03B5/626—Helical separators
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C1/00—Pretreatment of the finely-divided materials before digesting
  • D21C1/02—Pretreatment of the finely-divided materials before digesting with water or steam

Definitions

• This invention relates to the washing of chips from wood material.
• the manutacture pT pulp normally proceeds from wood material, which was chipped to small pieces, so-called chips. With these chips also follow along heavy impurit ⁇ ies (scrap) such as gravel,, metal pieces and the like. These impurities must be removed before the chips chem ⁇ ically or mechanically are disintegrated to pulp. This removal takes place in a so-called chip washer, which can be designed in different ways.
• the washing of the chips usually is carried out in two steps.
• the first step comprises the removal of heavy impurities in a container, in which chips and water are stirred by a rotor provided with blades, whereby the impurities sink to the bottom. Thereafter sand- and finer impurities are removed in a screw thickener. Between these steps the chips are collected in a tank, from which they are pumped to the second step.
• This conventional equipment has its weakness, because at a smaller size and weight of the impurities the separ ⁇ ation is uncertain, due to the fact that the particles to te separated are not caused to move to some separation zone, but are stirred together with the chips.
• the present invention offers a solution of the aforesaid problem.
• a tank equipped with a screw-shaped chute for chips and water the impurities can be separated along a relatively long sedimentation path and simultan ⁇ eously be affected by the centrifugal force. Chips and water, besides, are discharged continuously while at the same time the impurities are concentrated and thereby their separation is facilitated.
• the invention implies that the first separation step and the pump tank in a conventional arrangement can be replaced by a device, which can be connected directly to the subsequent thickener.
• Pig. 1 is a section through a device according to the invention, and Pig. 2 is a section II-II of the same device as shown in Pig. 1.
• This embodiment of the invention comprises a cylindric tank 1, the size of which, of course, depends on the desir ⁇ ed capacity.
• the tank can have a diameter, for example, of 1,5-3 m.
• a chute 2 which extends in the form of a screw slightly more than one turn about the tank wall. Por achieving a satisfactory separation effect, the length of the chute 2 in the tank should be at least half a turn. Preferably the length should be at least one turn.
• An inlet 3 for chips and water is located upwardly in the tank 1 at the upper end of the chute 2.
• the chute is outwardly defined by the tank wall and inwardly by an edge 4, the height of which decreases downward along the chute.
• the chute bottom is inclined outward to the tank wall, which inclination increases along the chute.
• the chute can be steeper at the beginning.
• the chute In its first part, preferably in its first quarter, the chute can also be provided with unevennesses or steps in the bottom, while its subsequent part should be smooth.
• a scrap outlet 5 is located at the end of the chute adjacent the tank wall.
• Said scrap outlet preferably is designed for interval discharge, i.e. provided with two valves open ⁇ ing altematingly.
• a water supply conduit 6 is.connected to the scrap outlet 5 in order to bring about a counterflow through the scrap outlet.
• the bottom of the tank 1 is ishaped conically so as to slope down to a central outlet 7 for washed chips. About the outlet 7 possibly one or several additional annular scrap traps 8 can be arranged. In connection to these traps openings can be located for manual emptying.
• the chips to be washed are supplied together with water through the inlet 1 down into the chute 2 and follow the chute downward. Heavy objects and particles are collected by sedimentation on the chute bottom.
• the separation of scrap is increased by action of the centrifugal force and by the fact, that the chute bottom is inclined outward to the tank wall. Unevennesses in the bottom of the first part of the chute and a steeper inclination promote the scrap removal in this ⁇ part of the chute, while in the subsequent part of the chute sedimentation is desired.
• the additional scrap traps 8 which can be arranged about the central outlet, are a safety at extreme scrap loads which in exceptional cases can arise. Such loads may, for example, occur when the chips are taken with a bottom scraping device of a chip bucket from a chip plane.
• the invention is not restricted to the embodim ⁇ ent shown, but can be varied within the scope of the in ⁇ vention idea.

Landscapes

• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Mechanical Engineering (AREA)
• Separation Of Solids By Using Liquids Or Pneumatic Power (AREA)
• Cleaning By Liquid Or Steam (AREA)
• Detergent Compositions (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20374062

Family Applications (1)

Country Status (8)

Families Citing this family (2)

Family Cites Families (3)

• 1988
  • 1988-11-25 SE SE8804261A patent/SE462566B/sv not_active IP Right Cessation
• 1989
  • 1989-11-20 AU AU45221/89A patent/AU4522189A/en not_active Abandoned
  • 1989-11-20 WO PCT/SE1989/000669 patent/WO1990006394A1/en not_active Application Discontinuation
  • 1989-11-20 JP JP51172989A patent/JPH04501891A/ja active Pending
  • 1989-11-20 EP EP19890912677 patent/EP0445143A1/en not_active Withdrawn
  • 1989-11-23 NZ NZ23150089A patent/NZ231500A/en unknown
  • 1989-11-24 CA CA 2003768 patent/CA2003768A1/en not_active Abandoned
• 1991
  • 1991-05-24 FI FI912523A patent/FI912523A0/fi unknown

Non-Patent Citations (1)

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