US2927738A - Rotary stock thickener and refiner - Google Patents

Description

March 8, 1960 E. P. ARPIN, JR 2,927,738

ROTARY STOCK THICKENER AND REFINER 75@ We me March 8, 1960 E. P. ARPIN, JR

ROTARY sTocx THICKENER AND REFINER s sheets-sheet 2 Filed Oct. 13, 1955 March 8, 1960 E. P. ARPIN, JR

ROTARY STOCK THICKENER AND REFINER 5 Sheets-Sheet 3 Filed Oct. 13, 1955 rares United This invention relates to improvements in rotary refining machines which are used to refine Wet, fibrous material, such as pulp, paper stock and the like.

Thepresent invention has particular application to a rotary reiner of the type having a cylindrical abrasive liner and a series of rotor elements carried on a central shaft and movable against the abrasive liner by centrifugal force upon rotation of the shaft, the material being moved progressively axially through the machine from an inlet to an outlet as it is treated bythe refining surfaces. lt has been found that for this type of machine to operate at its highest efficiency there is an optimum stock consistency which is higher than that normally fed to stock refiners. The reason for this is that the water, if above a certain percentage, tends to act as a cushion which prevents the pulp fibers from being most efciently acted upon by the refining elements of the machine. Also, excess water tends to propel the stock through the machine too rapidly for thorough action. Indications are that under high density conditions, treatment costs on this type of machine are very much reduced from that of any Y i known competitive equipment. It is also possible to provide a wide range of treatment effects under high density stock conditions which are not obtainable at lower densities.

I t is thus an important object of the present invention to provide a novel and improved rotary rener machine having means associated therewith to regulate the density of fibrous material being fed into the refining surfaces.

Itis a further object of the present invention to provide such a machine which is extremely simple in construction and which requires a minimum of floor space.

It is another object of the present invention to provide such a machine which will operate with or without a preliminary separate operation removing water from the stock.

It is afurther object of the present invention to provide improved means for controlling the amount of water removed from a stock mass prior to a refining action thereon, and to provide a water extracting `means which is of optimum construction from the standpoint of accumulated settlement and biological contamination.

Other and further objects, features and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevational View of a rotary refiner machine constructed in accordance with the present invention;

Figure 2 is a fragmentary longitudinal sectional view ofthe inlet end of the machine of Figure 1;

Figure 3 is an enlarged fragmentary transverse sectional view illustrating the means for extracting liquid from the inlet chamber for increasing the consistency of the stock;

Figure 4 is a fragmentary elevational View of the structure of Figure 3;

Figure` 5 is an end elevational View of the Aimpeller mechanism at the inlet end of the machine which co'- operates in increasing the consistency of the stock at the inletY end of the machine;

Figure 6 is a fragmentary enlarged sectional View taken generally along the line VI-VI of Figure 5; and

Figure 7 Vis an elevational view looking in the direction of the arrows VII-VII in Figure 5j As shown on the drawings:

The present invention is illustrated as being embodiedin a rotary reiiner machine indicated generally by the reference numeral 10, including a generally cylindrical shell or casing 11 which may be supported in ak generally horizontal orientation upon suitable supports l2. The shell l1 is provided with end plates 13 and lll closing the ends thereof, the end plate at then inlet end' of the machine having an inlet, pipe 16, and the plate le at the discharge end having a discharge pipe ll'7. A hollow shaft i9, Figure 2, extends axially through the refiner machine and is journaled in suitable bearings 2l) and 2l at the opposite ends of the machine. The shaft 19 is adapted to be rotated by means of a grooved pulley (not shown) securedon the lshaft externally of the casing lll. y

v The shell .il is provided internally with a liner '22, Figure 2, composed of a number of ring sections 23 Awhich are formed of suitable abrasive material, such as stone, metal or synthetic ceramic of an abrasive type.

A series of equally spaced helical grooves (not shown) extend longitudinally in the machine and form continuous passages along the inner surfaces Vof the ring sections 23 between the inlet and outlet ends of the machine.

ln the machine illustrated, a plurality of rotor assemblies 25 are mounted in peripheral sets of four each for rotation with the hollow shaft i9. Each rotor assembly includes a refining element 27 securedV in a backing member 2S pivotally mounted to a collar 2e keyed to the shaft i9. The refining elements 25 are pivoted at their leading ends so that as the shaft i9 is rotated, the refining elements 27 are centrifugally urged against the abrasive liner 22. Both the liner rings 23 and the rotor'elements 27 may be formed of stone, metal or of a synthetic cereamic of an abrasive type.

Means may be provided for maintaining a minimum clearance at all times between the surfaces of refining elements -27 and the abrasive surface of the liner rings 2,3, and such means may include push rods, such as indicated at 3l), the radial position of which is controlled by respective frusto-conical wedge members such as d3 carried on respective telescoping rods such as dit extending longitudinally inside the shaft 19. Means for adjusting the axial position of the rod 44 is illustrated in Figure l at di?, for example. The' precise structure of the refining section of the machine is not per se a part of the present invention, and reference is made to my prior patents for such details, for example to my Patent No. 2,475,869 or For regulating the consistency of the stock fed into the refining section of the machine, means is provided at the inlet end of the machine for extracting a controlled amount of excess water from the stock. Such means lintcludes impeller blades such as dll (Figure 2,) secured by bolts 51 to an annular plate 53, which is secured to the shaft 19. Said impeller blades are disposed between the inlet chamber 54 and the refining section of the machine defined by the shell ll. Referring to Figure 5, the arrow 5.5 indicates the direction of rotation of the impeller blades S0, and it will be observed. that the leading inner marginal portion Sila adjacent the plate 53 is curved opposite to the direction of rotation of the bladesrso as to generally impel material radially outwardly toward peripheral notches such as 60 in the plate 53. rl`he notches et) afford communication between the inletcham- Patented Mar. 8, 19d@ ber 54 and the refining section of the machine. The action of the impeller blades 50 tends to force material into the refining section of the machine and along the inner surfaces of the ring sections 23 to the outlet end of the machine.

Cooperating with the impeller blade 50 in removing excess liquid from the stock is a perforated ring 62 having apertures such as 63 therethrough leading from the inlet chamber to an annular chamber 65 formed in the inlet end plate 13. The ring 62 is secured to the end plate 13 by suitable means such as indicated at 66. A drain pipe 67 extends through the end plate 13 at the lower end thereof in communication with the drainage chamber 54 for delivering the liquid drained from the incoming stock to the outlet end of the machine, as will hereinafter be described.

As indicated in Figures 3 and 4, the openings 63 may be more or less uniformly distributed over the surface of the ring 62, and may be counterbored as indicated at 63a at the ends thereof remote from the inlet chamber to facilitate drainage. Also, as indicated in Figure 3, the axes of the openings 63 are inclined from a true radius opposite to the direction of rotation of the impeller blades 50, which is indicated by the arrow 70, in order to reduce the tendency of stock to plug the openings 63. 'Ihe outer edges 50h of the impeller blades 50 are preferably machined to fit to a rather close tolerance within the ring 62 so as to tend to have a cleaning effect upon the surface of the ring. To the same end, the edges 50h are provided with a slight bevel away from the leading edge Sllb as indicated at 50c (Figs. 5 and 6.)

For removing liquid from the drainage chamber 54 and for providing a very practical means for regulating the amount of liquid removed from the stock, a suitable variable speed pump 89 is connected with the drainage pipe 67 and may be driven by a suitable electric motor 81. A gate valve S2 may be interposed in the line 83 leading from the pipe 67 to the inlet to the pump 80 and the pump outlet may be connected by means of a line 85 to the outlet chamber of the machine defined by the dished outlet end plate 14 in a manner entirely similar to the inlet chamber defined by the inlet end plate 13. By regulating the flow of liquid through the pump 80, it is thus possible to control the amount of water removed from the stock in the inlet chamber.

Provision is made in the illustrated design to employ water under pressure to assist in cleaning out the openings 63 of the thickener should such be necessary, and to this end wash water under pressure from an outside source may be introduced into the pipe 87, with the gate valve 82 closed and hence through the lines 83 and 67 into the chamber 54. After passing through said openings 63, the water is discharged through an opening indicated at 90 (Fig. 2) at the top of the inlet plate 13.

The operation of the illustrated embodiment will now be understood. The stock or other fibrous suspension to be treated is introduced by means of the inlet pipe 16 into the inlet chamber. There, as the impeller blades 50 are rotated by means of the shaft 19, the material is forced against the perforated ring 62 by the action of centrifugal force. While the stock is in the process of being thickened, it is further somewhat compressed and moved laterally through the intake ports 6l) in the plate 53 which feed the stock into the refining section of the machine ahead of the rotating refining elements 27. The stock is forced between the liner 22 and the refining elements 27 by the pressure head under which the material is delivered to the inlet 16 and by the action of the impeller blades. The amount of water removed from the stock mass at the inlet chamber is regulated by means of the pump 80 which removes liquid from the drainage chamber 54 and delivers it to the outlet chamber or at other suitable points where it is mixed with the stock discharged from the refining section of the machine.

As indicative of the improved properties that can be imparted to the same stock as a result of refining the same at a higher consistency, such as can be obtainable by the use of my thickener and refiner, rather than that which is usual under normal operating conditions, the following comparison is given of representative results in the retining of west coast bleached Kraft pulp at a moderately low consistency (4 to 5% on an air dry basis) and at a relatively high consistency (9 to 10% on an air dry basis). The rate of feed through the refiner used was in each case 2000 lbs. of bone dry stock per hour.

The improved Mullen strength tear factor, and fold qualities resulted solely from the use of the higher consistency, since the same stock was fed continuously at the same rate of feed, in the one case at the normal operating consistency of 4 to 5% through a rotary rener not provided with my thickener feature but otherwise similar to that herein described, and in the other case at the same initial consistency or 4 to 5% through a combined thickener and refiner apparatus such as herein described and claimed. No auxiliary thickener ahead of my present rotary thickener and refiner was used; the stock consistency was raised to from 9 to 10% within the refiner itself by the action of the cooperating thicken ing elements of the device. The water so removed atl the feed end of the refiner was then returned for admixture with the refined stock discharged from the refiner.

Experience has proved that under normal operating conditions, excellent results are obtained in the refining of chemical pulp screen rejects at 7-8% consistency, and of mechanical pulp screen rejects at 3.5 to 4% consistency, whereas if refined at normal consistencies of 1 to 2%, as delivered from the screens, the results are unsatisfactory.

I claim as my invention:

1. In a rotary refiner for Wet fibrous material, a stationary shell having a cylindrical abrasive liner pr0 viding a refining surface, a drive shaft carrying centrifugally acting rotor elements having refining surfaces for coacting with said abrasive liner surface, inlet means cooperating with said shell to define an inlet chamber at one end thereof, outlet means cooperating with said shell to define an outlet chamber at the other end of said shell, means for introducing material into said inlet chamber, an impeller plate carried on said drive shaft and interposed between said inlet chamber and the refining section of the machine and having peripheral openings therein affording communication from said inlet chamber to said refining section, impeller blades in said inlet chamber and carried by said impeller piate for rotation therewith to impel the material in said inlet cham ber toward the periphery thereof, and a ring secured about the periphery of said inlet chamber and having a plurality of openings for removing liquid expelled from the material in said inlet chamber.

2. In a rotary refiner for wet fibrous material, a casing having a cylindrical abrasive liner providing an interior refining surface, a drive shaft mounted axially of said refining surface, centrifugally acting rotor elements carried by said shaft having refining surfaces for cooperating with said abrasive liner surface, said casing having an inlet chamber at one end thereof, an inter mediate refining section and an outlet chamber at the opposite end thereof, means for introducing material into said inlet chamber, impeller blades rotatable with said drive shaft and disposed in said inlet chamber for impelling material in the inlet chamber toward the periphery thereof, means affordingA communication between the inlet chamber and the refining section of the machine, means disposed about the periphery of the inlet chamber and having openings therein for draining liquid from the material in said inlet chamber, said impeller blades extending in close relation to said drain means to tend to scrape material therefrom and expel liquid therethrough, said drain means comprising a ring having apertures therein, and the axis of said apertures being inclined opposite to the direction of movement of the impeller blade so as to avoid clogging thereof by the material in said inlettchamber.

3. In a rotary refiner for wet fibrous material, a casing having a cylindrical abrasive liner providing an interior refining surface, a drive shaft mounted axially of said refining surface, centrifugally acting rotor elements carried by said shaft having refining surfaces for cooperating with said abrasive liner surface, said casing having an inlet chamber at one end thereof, an intermediate refining section and an outlet chamber at the opposite end thereof, means for introducing material into said inlet chamber, impeller blades rotatable with said drive shaft and disposed in said inlet chamber for impelling material in the inlet chamber toward the periphery thereof, means affording communication between the inlet chamber and the refining section of the machine, means disposed about the periphery of the inlet chamber and having openings therein for draining liquid from the material in said inlet chamber, said impeller blades extending in close relation to said drain means to tend to scrape material therefrom and expel liquid therethrough, said drain means comprising a ring having a series of apertures therein, and said apertures being enlarged at the ends thereof remote from said inlet chamber to facilitate drainage of liquid therethrough.

4. In a rotary refiner for wet fibrous material, a casing having a cylindrical abrasive liner providing an interior refining surface, a drive shaft mounted axially of said refining surface, centrifugally acting rotor elements carried by said shaft having refining surfaces for co operating with said abrasive liner surface, said casing having an inlet chamber at one end thereof, an intermediate refining section and an outlet chamber at the opposite end thereof, means for introducing material into said inlet chamber, impeller blades rotatable with said drive shaft and disposed in said inlet chamber for impelling material in the inlet chamber toward the periphery thereof, means affording communication between the inlet chamber and the rening section of the machine, and means disposed about the periphery of the inlet chamber and having openings therein for drainkfining surface, centrifugally acting rotor elements carried by said shaft having refining surfaces for cooperating with said abrasive liner surface, said casing having anV inlet chamber at one end thereof, an intermediate refining section and an outlet chamber at the opposite end thereof,

means for introducing material into said inlet chamber, d

impeller blades rotatable with said drive shaft and disposed in said inlet chamber for impelling material in the inlet chamber toward the periphery thereof, means affording communication between the inlet chamber and the refining section of the machine, means disposed about the periphery of the inlet chamber and having openings therein for draining liquid from the material in said inlet chamber, and pump means for delivering liquid drained'from the inlet chamber to said outlet chamber.

6. In a rotary refiner for wet fibrous material, a unitary casing having an inlet chamber at one end thereof, an intermediate refining section and an outlet chamber at the opposite end thereof, said casing having means pro viding a cylindrical abrasive liner in said intermediate refining section providing an interior refining surface, a drive shaft extending the length of said casing axially of said refining surface, centrifugally acting rotor elements carried by said shaft having refining surfaces for cooperating with said abrasive liner surface, means for introducing material into said inlet chamber, means defining a radially extending wall between said inlet chamber and said intermediate refining chamber having apertures providing axial communication between said inlet chamber and said intermediate chamber at the periphery of said inlet chamber, impeller blades disposed about said drive shaft in said inlet chamber for impelling material toward the periphery thereof, a perforated ring having a perforated portion thereof extending generally axially and defining the radially outer margin of said inlet chamber, and means controlling the pressure at the radially outer side of said ring outside of said inlet chamber to regulate the amount of water removed from said material in said inlet chamber.

References Cited in the file of this patent UNITED STATES PATENTS in said inlet chamber, -the

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