Two-stage variable intensity refiner
First Claim
1. In a method of operating a high consistency pulp refiner of the type having a pressurized casing (12) containing opposed grinding discs (14,18) mounted for counter-rotation abut a common axis (26) and between which material to be refined is introduced near the axis so as to move generally radially outwardly through an inner refining zone (40) between the discs while producing steam as a result of the refining action, the partially refined material and steam then moving through a generally radially outer refining zone (50) between one (14) of the discs and a stationary grinding surface (54) situated generally radially outwardly of the other disc (18), whereupon the refined material and steam are discharged from the casing through a material outlet (62), wherein the improvement comprises:
- removing from the casing, at least some of the steam generated in the inner refining zone (40), by discharging the removed steam from the casing through a dedicated steam discharge opening (66) other than said material outlet (62) before said generated steam enters the outer refining zone (50), wherein steam situated between the inner and outer refining zones is at a first pressure and the steam discharge opening is at a second pressure;
adjusting the second pressure during operation to control the amount of steam discharged from the casing as between the material discharge outlet (62) and the steam discharge opening (66); and
rotating one disc at a constant speed different from the speed of rotation of the other disc.
1 Assignment
0 Petitions
Accused Products
Abstract
A high consistency pulp refiner of the type having a pressurized casing (12) containing opposed grinding discs (14,18) mounted for counter-rotation about a common axis (26) and between which material to be refined is introduced near the axis so as to move generally radially outwardly through an inner refining zone (40) between the discs while producing steam as a result of the refining action. The partially refined material and steam then move through a generally radially outer refining zone (50) between one of the discs (14) and a stationary grinding surface (54) situated generally radially outwardly of the other disc (18), whereupon the refined material and steam are discharged from the casing through a material outlet (62). A generally axially extending flow path (64) originates between the first refining zone (40) and the second refining zone (50), for diverting steam produced in the first refining zone away from the second refining zone while the partially refined material moves from the first refining zone to the second refining zone.
59 Citations
11 Claims
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1. In a method of operating a high consistency pulp refiner of the type having a pressurized casing (12) containing opposed grinding discs (14,18) mounted for counter-rotation abut a common axis (26) and between which material to be refined is introduced near the axis so as to move generally radially outwardly through an inner refining zone (40) between the discs while producing steam as a result of the refining action, the partially refined material and steam then moving through a generally radially outer refining zone (50) between one (14) of the discs and a stationary grinding surface (54) situated generally radially outwardly of the other disc (18), whereupon the refined material and steam are discharged from the casing through a material outlet (62), wherein the improvement comprises:
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removing from the casing, at least some of the steam generated in the inner refining zone (40), by discharging the removed steam from the casing through a dedicated steam discharge opening (66) other than said material outlet (62) before said generated steam enters the outer refining zone (50), wherein steam situated between the inner and outer refining zones is at a first pressure and the steam discharge opening is at a second pressure; adjusting the second pressure during operation to control the amount of steam discharged from the casing as between the material discharge outlet (62) and the steam discharge opening (66); and rotating one disc at a constant speed different from the speed of rotation of the other disc. - View Dependent Claims (2, 3, 4, 5)
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6. In a high consistency pulp refiner of the type having a pressurized casing (12) containing opposed grinding discs (14,18) mounted for counter-rotation about a common axis (26) and between which material to be refined is introduced near the axis so as to move generally radially outwardly through an inner refining zone (40) between the discs while producing steam as a result of the refining action, the partially refined material and steam then moving through a generally radially outer refining zone (50) between one of the discs (14) and a stationary grinding surface (54) situated generally radially outwardly of the other disc (18), whereupon the refined material and steam are discharged from the casing through a material outlet (62), wherein the improvement comprises:
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means (64) operative between said other disc (18) and said stationary grinding surface (54), for diverting steam produced in the inner refining zone away from the outer refining zone while the partially refined material moves from the inner refining zone to the outer refining zone; said inner and outer refining zones (40,50) are substantially radially spaced apart and the space therebetween defines a transition region (48) which, during operation of the refiner, contains a mixture of partially refined pulp and steam at a first pressure (P4); the material outlet (62) is at a second pressure (P2); means (28) are provided for supplying high consistency feed material at a fourth pressure (P1), through the one disc (14) to the inner refining zone (40); the means for diverting steam (64) includes means for defining a by pass flow path (73,74) from the transition region to a dedicated steam discharge opening (66) in the casing (12); means are provided for establishing a third pressure (P3) in the steam discharge opening, that is lower than the pressure (P4) in the transition region (48); and means are provided for independently adjusting the pressure (P3) in the steam discharge opening (66) and at least one of said feed pressure (P1) and pulp outlet pressure (P2). - View Dependent Claims (7, 8, 9, 10)
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11. In a high consistency pulp refiner of the type having a pressurized casing (12) containing opposed grinding discs (14,18) mounted for counter-rotation about a common axis (26) and between which material to be refined is introduced near the axis so as to move generally radially outwardly through an inner refining zone (40) between the discs while producing steam as a result of the refining action, the partially refined material and steam then moving through a generally radially outer refining zone (50) between one of the discs (14) and a stationary grinding surface (54) situated generally radially outwardly of the other disc (18), whereupon the refined material and steam are discharged from the casing through a material outlet (62), wherein the improvement comprises:
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means (64) operative between said other disc (18) and said stationary grinding surface (54), for diverting steam produced in the inner refining zone away from the outer refining zone while the partially refined material moves from the inner refining zone to the outer refining zone; and said inner and outer refining zones (40,50) are substantially radially spaced apart and the space therebetween defines a transition region (48) which, during operation of the refiner, contains a mixture of partially refined pulp and steam; and said means (64) for diverting steam has an upstream portion (73) in fluid communication with said transition region (48) and a downstream portion (100) in fluid communication with a dedicated steam discharge opening (66) in the casing (12), other than said material outlet (62).
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Specification