A conical refining gap inside one refiner housing (Fig. 4.30).

The latest developments on the market are cylindrical refiners; the Papillon™

(Andritz) (Fig. 4.31) incorporates the advantages of hollaender beating with the

Continuous refiner principle. Also available are multiconical refiners; an example

is the TriConic® (Pilao) (Fig. 4.32), which is a medium-angle, double-flow conical

Refiner with a low refining intensity and low no-load.

Fig. 4.27 The single-disc refiner (Metso RGP 268).

Fig. 4.28 The double-disc refiner (Metso RGP 68DD).

Mechanical Pulping Processes

Fig. 4.29 The twin-refiner TwinFlo™ (Andritz).

Fig. 4.30 The conical-disc refiner (Metso RPG 82 CD).

Fig. 4.31 The cylindrical refiner Papillon™ (Andritz), with an

Open housing for plate change.

Refiner Processes 1107

Fig. 4.32 The multiconical refiner TriConic® (Pilao). Left: Refiner

with an open housing. Right: TriConic®; upper diagram,

Principle of operation; lower diagram, plate design.

Fig. 4.33 Double disc refiner concept.

And 2, Rotating discs; 3, active parts

Of the discs (refiner plates); 4, entrance

Area into the refining zone; 5, outlet from

The refining zone; 6, chip feed.

Mechanical Pulping Processes

The working principle of mechanical pulp refiners is explained by means of the

Double disc concept in Fig. 4.33. The pulp is treated between two refiner discs,

Enters in the center at the shaft, and passes the discs from center to side. Refining

Plates constructed from high-strength steel and with different profiles are

Mounted on the refiner discs, which are pressed together hydraulically. The refining

Gap has an important influence on mechanical pulp quality.

An overview of the design of selected refiner types is provided in Tab. 4.3.

Tab. 4.3 Characteristics of selected large-size refiner types.

Refiner type Characteristics

RGP 268 SD Single-disc refiner (Metso)

Motor size 15 MW, disc diameter 1728 mm (68 in), rotational speed

R.p.m.

RGP 68 DD Double-disc refiner (Metso)

Motor size 30 MW, disc diameter 1730 mm (68 in), rotational speed

R.p.m. (50 Hz) or 1800 r.p.m. (60 Hz); designed pressure 1.4 MPa

RGP 82 CD Conical-disc refiner (Metso)

Motor size 30 MW, disc diameter 2080 mm (82 in), rotational speed

R.p.m. (50 Hz) or 1800 r.p.m. (60 Hz); designed pressure 1.4 MPa;

Refining surface 3.2 m2

Twin 66 Twin refiner (Andritz)

Motor size 24 MW, nominal disc diameter at 1800 r.p.m.: 1680 mm (66 in)

Papillon CC-600 Cylindrical refiner with center feed (Andritz)

Motor size 2000 kW, diameter of refining area 600 mm, idle load 160 kW

TriConic Type

RTC 6000

Multiconical refiner (Pilao)

Motor size 880–1470 kW, throughput 200–1800 t day–1

Refiner plates are the “heart” of the refining process. The type of refiner plate

Design chosen is specified for a certain pulp quality and depends on the requirements

Of the paper machine. These depend on the type of paper produced and on

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