CA1045865A

CA1045865A - Vented disc refiner

Info

Publication number: CA1045865A
Application number: CA267,587A
Authority: CA
Inventors: Lawrence Skeen
Original assignee: Bauer Brothers Co
Current assignee: Bauer Brothers Co
Priority date: 1976-02-06
Filing date: 1976-12-10
Publication date: 1979-01-09
Also published as: FI770245A; JPS5857559B2; SE422819B; ATA69677A; SE7701182L; JPS5296459A; FI59437C; BR7700576A; FI59437B

Abstract

VENTED DISC REFINER

ABSTRACT OF THE DISCLOSURE:

A disc-type refiner wherein the means incorporating the refining surfaces are positioned in opposed, rel-atively adjacent, closely spaced relation and one thereof is formed to include at least one passageway through which steam created in the refining of material between the refining surfaces may be simply and quickly vented. A duct means is provided to receive and carry steam from the passageway to the exterior of the refiner housing, to facilitate use or disposal as and where desired. Means are included to control the amount of steam being vented and to maintain the venting arrange-ment on adjustment of the spacing between the refining surfaces.
In the preferred embodiment illustrated, the invention features are incorporated in a double revolv-ing disc refiner which, by reason of the improvements of the invention, may be operated under either atmos-pheric or pressurized conditions. In either case con-siderable benefit is reflected in the refining pro-cedure and the quality of its end product.

Description

ACKGROUND OF THE INVENTION:
This invention relates to improvements in disc re-finers providing for a simple, effective and controlled venting of steam produced in a ~isc refining operation.
It is particularly advantageous in application to double revolving disc refiners and it will be so described by way of illustration. However, it is to be understood, and should become obvious, that the application of the invention is not so limited, and such is not intended.
The invention is directed to minimizing problems long evidenced in use of the prior art disc refiners. It has been found that substantially all the power applied in a disc refiner is converted to heat, developed as material is reduced between the relatively opposed refining surfaces of the refiner discs. A major portion of this heat functions to convert the moisture or liquid which is present to steam.
Another portion of this heat is absorbed by the material being refined. The degree of heat developed is the source of the problems to a solution of which the present invention is directed. To understand the problem, consider if you will that in the operation thereof a disc refiner will generate heat capable of producing about a ton of steam at 212F.
per ton of wood or fibrous materials passed between the re-finer discs when power is applied at the level of 60 H.P.
days per ton of the material delivered in chip form at 15%
consistency. Such a level of operation, or one with an even higher "effective" power input, is desirable to en- -able higher consistency refining and to obtain high quality products or, in the alternative, to enable the obtaining of the same quality products with a lesser power input.
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However, due to the considerable magnitude of steam de-veloped, it has been found difficult if not impossible to operate a disc refiner under such conditions for any period of time without serious and undesirable consequences. As a matter of fact, experience has sho~n that when utilizing prior art disc refiner equipment one cannot afford normally to put more than about 50 H.P. days per ton into any disc refining operation and expect any degree of operating ef-ficiency.
The nature of the operational problems solved by the present invention is exemplified as follows.
With an overabundance of steam, while part of the steam ~ .
developed will exit with the refined material and in such case merely represent a loss of energy, the steam remaining in the disc refiner will, in conventional equipment, often times create a blowback condition. The import of such a condition is that the steam will move to interfere with the inflow to the refiner of the material to be refined. Of . .
particular concern in the production of fibrous pulp is the fact that the interference of the steam will cause a non-uniform rate of material infeed and consequently a non-uniform quality of the end product issuing from the refiner.
In many instances it has been found that the quantity of steam produced between the refining surfaces of a disc re-finer in the course of its operation is so great that there is not only an interference with infeed but in fact a de-velopment of sufficient pressure in the eye of the refiner to completely block incoming material from passage to and between the refining surfaces of the refiner discs. This last can occur even though a positive displacement infeed .'-.: ~,

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iO4S865 device is provided in the feed passage leading to the inlet to the refiner. As a matter of fact, the restriction of the infeed passage by the positive displacement feed device can contribute to the buildup of the pressure created in the eye of the refiner. In any case, the foregoing presents a concise description of the problems in the prior art which can be alleviated by usage of embodiments of the present invention.
It has been the practice in the prior art to offset some of the problems above enumerated by the introduction of excess water with the material heing refined, the purpose being to quench the steam. While this has helped to some degree, it is not only wasteful but it does cause an un- -desirable reduction in the consistency of the material be-ing refined and a consequent reduction of the quality level of the resultant end product.
SUMMARY OF THE INVENTION:
The primaxy objective and achievement of the present invention is to reduce the normally encountered buildup of excessive pressure in the "eye" of a refiner during a disc refining operation.
To illustrate a means and method by which this objective can be achieved, the present disclosure shows the invention as embodied in a double revolving disc refiner which is basically similar in construction to that of the refiner il-lustrated in U.S. Patent No. 3,709,443. Such a refiner in-cludes a pair of discs the refining surfaces of which are positioned in directly opposed, adjacent and relatively closely spaced relation, which discs are caused to rotate, one relative the other, as material to be refined is passed ~-,. .::

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between their opposed refining surfaces. In accordance with the present invention, the one disc constituting the control end disc, in the example illustrated, is shown to include a plurality of vent holes or passageways communi-- cating at one end with an area of the space between the discs known as the "eye" of the refiner, or adjacent thereto.
The outermost ends of the vent holes or passageways, which are arranged to open from the backside of the control end disc, are commonly communicated with conduit means the nature and extent of which provides for steam received there-in by way of said passageways to be directed to discharge exteriorly of the refiner housing. The conduit means is so coupled to the control end disc as to maintain its oper-ative relation to the vent holes or passageways in the event the control end disc may be moved to or from the ` opposite (feed end) disc to produce a required spacing be-tween the disc refining surfaces.
Particular features to be noted in the illustrated em-bodiment of the invention include the provision of vent holes or passageways the axial length of each of which is relatively short since it extends directly through the body of the control end disc in an essentially straight line path, from one face of the disc to the other. In connection with a feed end disc such as illustrated, the exemplary embodi-ment shows an arrangement wherein the feed passages in the feed end disc and the vent holes or passageways in the control end disc commonly communicate with the same general area of the space between the discs, adjacent their centers.
By virtue of the particular nature and positioning of the vent holes or passageways in the control end disc as here provided and their continuing common communication with the conduit means as indicated, excess steam produced in the course of a disc refining procedure is continuously and effectively channelled from between the discs and to points exterior to the refiner housing. Means provided to regulate this transfer of steam insure optimal control of the environment within the refiner and in the area between the disc refining surfaces. By virtue of this arrangement, the invention has produced unobvious results in its appli-cation.
One important benefit of the invention is that it en-ables disc refiners to operate on slurries having a higher consistency of solids and with an "effective" power input at a much higher level, even up to 70 to 90 H.P. days/ton of the material delivered, with proportional increase in the quality of the end product. By the same token it obviates the need for applying excess water to quench steam as would -otherwise be required. The end result, in any case, is to reduce the pressure developed in the eye of the refiner and to enable the refiner to produce the same quality pulp at lower H.P. days/ton than was previously possible. De-rivative results include more uniform infeed of material to be refined and an elimination of overload and stoppage of a positive displacement feeder, if the same should be employed. Where the refiner is to operate under pressur-ized conditions, the invention may enable the elimination of a cross screw such as is normally required to in-sure positive delivery of material to the refiner. Of 104S~365 course, inherent in the operation of a disc refiner modified in accordance with the invention is the conservation of energy.
I~hile the invention will be described as incorpor-ated in a double revolving disc refiner, it should be obvious therefrom that similar principles may be employed to modify a single disc refiner to embody the features of the present invention.
It is accordingly a primary object of the inven-tion to provide improvements in disc refiners render-ing them more efficient and satisfactory in use, ~- adaptable to a wider variety of applications and unlikely to malfunction.
A further object of the invention is to provide ` improvements in disc refiners enabling them to oper- -ate with delivered materials being maintained at a higher consistency of solids.
- A further object of the invention is to provide improvements in a disc refiner obviating the problems normally produced by the production of steam in the refining procedure.
Another object of the invention is to provide im-provements in disc refiners enabling such refiners to produce a quality end product at lower H.P. days/ton than was previously possible.

- ~045865 An additional object of the invention is to operate a disc refiner in a manner to conserve energy and to produce higher ~uali~y end products by obviat-ing the need for exce~ss water to quench steam in the disc refining operation.
A further object of the invention is to provide a disc refiner with improvements possessing the advan-tageous features, the inherent meritorious character-istics and the means and mode of use herein described.
With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Pat-ent consists of the features of construction, the parts and combinations thereof, and the mode of oper-ation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.
Referring to the accompanying drawing, wherein one but not necessarily the only form of embodiment of the invention is illustrated, Fig. 1 is a generally diagrammatic illustration, in cross section, of a double revolving disc refiner embodying features of the present invention.
The refiner illustrated in the accompanying draw-ings to exemplify an embodiment of the present invention is a modified version of that illustrated ~
; in the previously mentioned U. S. Patent 3,709,443. ~ -As may be seen, the refiner is a double revolving ~ -disc refiner, both of the refiner discs being arranged ~

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to rotate, with each moving re:Lative the other.
As will be self-evident only 80 much of the ref-iner detail is here illustrated or described as may be neces~ary for an understanding of the present invention. The nature and character of the parts not shown or described in detail obviously may be seen with re~erence to the aforementioned U. S. Letters Patent, or they are conventional and will be well known and understood by tho~e versed in the art.
The refiner shown in the arawings comprises a pair of refiner discs 28 and 30 housed within and free and clear of the interior surface of the refiner case 10. The case 10 is comprised of a vertically oriented tubular waist portion 16, capped to one end by a dome-shaped top portion 12 and to the other vertical extremity by a dome-shaped bottom portion 14 which is relatively inverted. As seen in the draw-ing, in transverse section, the relatively remote wall portions 18 and 20 of the waist portion 16, in an axial sense, are orientea in generally vertical planes.
Also disc 28 i8 80 mounted that its back surface is in immediately ad~acent, closely spaced relation to the ~;
interior surface of the wall portion 18 while its operating surface is in a plane parallel to 3aid wall portion.
The refiner di3c 28 has a central aperture accom-modating one end of a drive ~haft 40 to which it is fixed. The shaft 40 is directed outwardly of the case _g_ 10 through the center of an inlet aperture 17, pro-vided in the wall portion 18 immediately to the rear (or to the left as illu~trated) of the disc 28.
The interior wall surface of the wall portion 18 include~ a recessed shoulder 22 which rims the aper-ture 17. The outer peripheral limit of the shoulder 22 is bounded by a shallow cylindrical wall surface 24. A ~imilar shallow cylindrical, axially directed, wall surface 25, aligned with and in end spaced rel- :
ation to the wall surface 24, i8 defined by an annular ring-like projection from the rear face of the disc 28.
Seated to the rear surface of the disc 28 and against the wall surface 25 is the base portion of an axially pro~ected ring element 46. The projected end of the ring 46 provides an annular vertically oriented surface disposing in an almost touching and parallel relation ~:
to the shoulder 22.
The configuration of the innermost peripheral sur-face of the ring 46 i~ such that its pro~ected end por-tion 27 has a cylindrical contour adapted to form adirect axial extension of the wall surface bounding the aperture 17. Following the surface portion 27, in the direction of the disc 28, the remainder of the inner peripheral ~urface of the ring 46 i3 provided with a conically expanding configuration. ~ :
The line defining th~ expanded extremlty of the inner perlpheral surface of the ring 46 is in p~riph-erally rimming relation to the entrance ends of a . ~ . .

1045865plurality of infeed passage~ 29 formed in the body of the di~c 28. The entrance ends of the passages 29 are arranged in a circularly spaced relation, in concentric, ad;acent, radially spaced, relation to the drive shaft 40. The pas~ages 29 are straight line passages formed to extend to the operating face of the disc 28 in a conically divergent pattern, clearly ~een from their generally diagrammatic ~howing in the drawing. The discharge ends of the passages 29 open from the operating face of the disc 28 at loc-ations immediately ad~acent the inner peripheral limit of a series of conventional, circularly arranged, ref-iner plate~ fixed to provide the disc with its refining surface.
The outer peripheral surface of the ring element 46 is formed with a circumferential groove nesting a complementarily shaped male formed projection provided on a r~ng-like element 26 fixed in connection with the wall surface 24 bounding the shoulder 22. By virtue of it~ clo~ely spaced relation to the ad~acent sur-face of the shoulder 22 and the ring element 26, the ring element 46 provides, on rotation thereof with the disc 28, a seal. This seal prevents material fed through the inlet aperture 17 from bypassing the disc 28 in a manner believed obvious and well known in the art.
A tubular wall ~tructure forming a feed spout 32 defines a material feed pa~age 34 directed downwardly : , to the inlet aperture 17, in a verti~ally inclined path. The lowermo~t end of the wall structure forming the feed spout 32 embodies an external flange which is abutted with and welded to a reces~ed shoulder formed : in the outer surface of the wall portion 18 of the ca~e 10, in immediately rimming relation to the aperture -17.
In the vertical plane of it~ discharge end, the diameter of the feed passage 34 i8 slightly less than that of the inlet aperture 17. By reason of the noted difference in dimension and the centered alignment of the lower end opening of the feed passage 34 with respect to the upper portion of the inlet aperture ~::
17, the flanged lower end portion of the wall ~truc-ture of the feed spout will overlap the lowermost portion of the inlet aperture 17. This arrangement is provided to enable material directed through the inlet aperture to more expeditiously flow to and ; through the infeed passages 29 in the disc 28.
As the drive shaft 40 extends outwardly of the : case 10 through the center of the aperture 17 it i~
fir~t directed through the lower end portion of the feed passage 34 and then through a packing gland and follower assembly 42 defining a seal thereabout as it pro~ects through an opening in the wall portion of the feed spout 32 located in an ad~acent vertic-ally spaced relation to it~ lowermost end portion.
Within the case 10, the refiner plates in ~ -12-.. '.......... , ., .: ,.' ~' , ~ - . ..

lV45865 connection with the outer peripheral area of the disc 28 are in immediately opposed, clo~ely adjacent, rel-ation to ~imilar refining plate~ fixed to the adjacent operating ~urface of the disc 30. In accordance with the present invention, the embodiment thereof in the di~c 30 here illustrated proviaes that the di~c ha~
a plurality of straight line passageways defining vent hole~ which open at one end from the body of the di~c 30, from an annular portion of its operating face, to the space between it and that of the disc 28, at location~ immediately inward of the inner radial limit of the di~c refining plates. This annular portion of the operating fa¢e of the disc 30 i~, in the example illu~trated, in direct and axial alignment with an annular surface portion of the operating face of the disc 28 occupied by the circularly ~paced discharge ends of the infeed passages 29. As shown in cros~
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section in the drawing, the vent holes 31 extend from the operating face of the disc 30 to its rear or opposite face in a conic~lly convergent pattern.
This provides that the vent hole~ open from the oppo~-ite face of the disc 30 in concentric, ad~acent, and : closely spaced relation to an aperture at the disc center accommodating one end of a drive shaft 48 to which the di~c i8 suitably fixed.
; In the mounting of the refiner disc 30 the drive shaft 48 i8 placed in direct coaxial alignment and in end sp~ced relation to the shaft 40, as may be :

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~ 045865 seen from the accompanying drawing. The shaft 48 is thus arranged to extend outwardly from the case 10 and through the center of an appropriate aperture provided in the wall surface portion 20. This aper-ture in the wall surface portion 20 is partially capped by an annular cup-shaped plate segment 53 including an external flange at the mouth thereof by means of which the plate ~egment is seated to and connected with the wall portion 20, as may be clearly seen with reference to the accompanying drawing. Suit-able ring-shaped bearing means provided to line the inner periphery of the plate segment 53 accommodates, in bear$ng relation thereto and for axial ad~u~tment therein, one end of a tubular cartridge 52. The : cartridge 52 embodies therein, in a conventional manner, a packing gland and follower assembly 50 accommodating the pro~ection therethrough of the shaft 48 as it ex-tends in a sense outwardly of the case 10. As may be seen, the external diameter of the aartridge 52 i8 en-larged outwardly of the plate segment 53 where the cartridge is abutted to a shoulder prov~ded by an en-largement of the drive shaft 48. Bearings (not shown) : provide for the rotation of the shaft 48 within the cartridge 52 and the cartridge i~ suitably fixed to the ~haft for movem*nt therewith. Thus the cartridge .; 52 ~8 contained for movement with the disc 30 and the shaft 48 in the event the lattèr are axially adju3ted to achieve a de~ired spacing between the refiner plates positioned in ad~acent closely ~paced relation by their connaction with and mount on the di~cs 28 and 30.
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The adju~ting mechanism may be of any suitable char-acter well known to those versed in the art. Since it form~ no part of the present invention, it is neither shown nor further described.
Attention is directed to the fact that the drawing illustrates bearing hou~ings 44 and 54 re~pectively for the shaft 40 and the shaft 48 and cartridge 52. Such bear-ing housing~ will be provided on the conventional refiner base to which the refiner illu~trated will be convention-ally mounted together with the drive motors for the ~hafts -~ 40 and 48. Again, since such details are une~sential to an understanding of the present invention, they a~ well as the other details of similar character are neither shown nor part~cularly described. S-~ch details as this, and detail~ of a mechanism for axially adjusting shaft 48, are exemplified in the aforementioned U.S. Patent 3,709,443.
Referring further to details contributing to the embodiment of the present invention, attention i~ dir-ected to the fact that the openings of the vent holes or pa~ageways 31 from the rearmost face of the disc 30 are arranged in a closely and circularly spaced annular arrangement, concentric to and immediately about the hub portion of the disc 30 through which extends the shaft 48. The outer peripheries of the rearmost openings are immed$ately rimmed by a recessed shoulder 41 ~ormed in the ro~rmost face of the disc 30. The shoulder 41 provides a ~eat for a ~uitably , . :, .

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1~145865 fixed ring 58 which i5 axially projected in the dir-ection of the wall surface portion 20 of the case 10.
The projected extremity of the ring 58 is tele~coped about and accommodates therein one end of a co-axial tubular sleeve structure 56 the opposite end of which i8 suitably fixed by a sealed engagement thereof with the innermo~t face of the closure plate ~egment 53.
The relation of the inner surface of the ring 58 to the outer surface of the sleeve 56 is such that on a rotation of the disc 30 a continuing seal i~ provided there-between. The seal is of a nature to accommodate an axial movement of the shaft 48, to provide for such fine ad~ustment of the spacing between the surfaces of the relatively opposed refining plates on the discs 28 and 30 as may be de~ired.
~The sleeve structure 56 iB provided with an opening ;57 in which i8 fixed one end of an elliptical configured tubular duct segment 59 defining one end portion of a duct ~tructure 33. The latter provides a continuing pas-sage one end of which opens to the interior of the sleeve 56 as des¢ribed and the opposite end of which i8 located exterior to the case 10. In the case of the example ; illu~trated, a ~egment 61 of ~he duct structure 33 which immediately follows the segment 59 i~ formed to provide a generally conical expansion of the duct passage to achieve an enlarged cro~s section thereof which i~ gener-ally uniformly continued in following segments of the duct structure as it is extende~ through an aperture provided ~-in the top of the case 10, at which point a seal is ; ' '.

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provided between the case 10 and the duct structure 33.
For purposes of illu~tration the duct structure i~ merely shown to extend to some point exterior to the case 10.
The duct structure may be interconnected to a heat recov-ery system or any other apparatus provided in a refining in~tallation, to deliver steam thereto as and when required. Incorporated in the duct structure 33 i~ a suitable valve 35 which may be ~electively adjusted to determine the amount of ~team that may be permitted to pa~s from the case 10 by way of the duct 33. While the opening 57 is shown to be po~itioned at the top portion of the sleeve 56, this is merely for convenience of illu5-tration. It will be obvious to those versed in the art that the opening 57 may be otherwise located.
In the case illu~trated the feed spout 32 and a ~` tubular extension 38 thereof, by mean~ of which the feed spout connects to a supply of material to be ref-ined, incorporates in its feed passage a screw type ;`
po~itive displacement feeder device 36. While this device iB illustrated, under certain conaitions and applications such as in the use of the disc refiner as a pres~urized refiner the feeder 36 may in accord-ance with the invention be eliminated.
The aforementioned embodiment particularly des-cribed and diagrammatic~lly and schematically illu3-trated will function in a refining procedure, as follows.

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In the operation of the cli~c refiner illustrated the invention improvements function very simply and very effectively. As the material to be refined 18 directed inwardly of the feed ~pout 32 utilizing the screw fee~er 36 and operating the refiner a~ a free discharge refiner, the material delivered by the ~crew will drop from the lower end thereof into the relatively clear discharge end portion of the passage 34. Under the influence of the material further delivered, this material to be refined will be cau~ed to move smoothly and freely to and through the inlet aperture 17 and, by way of the ring 46, into and through the flow pas- -sages 29 of the rotating di~c 28. From the flow pas-sage~ 29, the material to be refined will enter the space between the operating face~ of the relatively rotating discs 28 and 30 immediately inward of the refining throat at the entrance ends of the relatively opposed refining ~urfaces provided on the di~c~. Due to the inclination of the flow pa~sages 29, the material to be refined will tend to move, immediately, bet- ;
ween the refining surfaces and radially outwardly thereof, in the process of which to h~ve their fibers separated, one from the other. As i~ well known, in ; -view of the slurry form of the material as generally delivered in a pulp refining operation, steam will be developed a~ the power applied in the disc refining procedure i8 converted to heat by reason of the refin~
ing operation. In accordance with the present invention, rather than exce~ steam building up between the discs and in the eye of the refiner, the vent holes provided by the passageways 31 wlll provide paths for portion~
of the ~team to pa88 directly through the body of the disc 30 and into the sleeve 56, to exit by way of the duct 33. The steam may be permitted to exit either freely or to a degree permitted by the setting of the valve 35, the latter being ad~ustable to provide a controlled passage for steam to move from the duct - 10 33 to a place of u~e. It will be cbvious, of course, that this steAm, which i8 so quickly and easily vented, can be channelled by suitable plumbing into a pre-steamer or digester ahead of the refiner. Thi~ will most effectively reduce or eliminate the requirement for fre~h steam that would normally be required and applied in ~ refiner installation absent the u~e of the improvement~ of the present invention. Another benefit of the venting of steam as here provided i8 that the reduction in presQure re~ults in less ~team being di~charged with the refined material. Consequently there i~ a significant ~avings in energy which can be utilized elsewhere.
Attention i8 dirscted to the fact that due to the centrifugal force developed in the refining procedure, any particles which might tend to move from between the di~c operating ~urfaces and into the pa~ageway~ or vent holes 31 would be drawn therefrom under the influence of the centrifugal force and inducsd to move -19~

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1~)45865 radially outward between the rlefining plate~ on the counter-rotating operating surface~ of the discs28 and 30.
A feature of significance in the particular embod-iment illustrated i~ that manufacturing costs can be saved by the arrangement of the pas~ageway~ 31 in the disc 30 to be e~sentially the same as the arrangement of the infeed passages 29 in the disc 28. One can then use ~he ~ame disc as both an infeed disc such as the disc 28 and a control end disc ~uch a~ the disc 30.
Of cour~e, while thi~ is desirable, this arrangement i8 not required to utilize the benefits of the inven-tion.
Under the circum~tances, by rea~on of the very ~imple venting arrangement, whereby there is a natural venting from the eye of the refiner or ad~acent thereto, blowback condition~ are virtually eliminated. This means that with a free discharge refiner one can have a uniform rate of feed, determined by the operation of ;
the feeder ~crew 36. The flow of material will in any case be smoothly directed to the throat of the refiner and move radially outward therefrom under the influence of centrifugal force. In its radial outward movement the material will be refined ln accordance with the reduction set into the refiner by vlrtue of the nature of the refining ~urfaces of the refiner plates and - ..................... .. . ~., , . , . :.
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their spacing. The inflowing material can be readily controlled to permit the ~team developed in the refin-ing procedure to be directed Inwardly toward~ the eye of the re~iner and quickly vented to the degree desired, to be directed clear of the refiner case by way of the duct 33. The regulation of the steam permitted to exit will be such to insure the required conditioning of the material during the refiner operation.
In the instance illu~trated there i~ a 3howing, of a generally d$agrammatic nature, evidencing an outlet 37 from the ca~e 10 through which the refined materi~l ~ssuing from the outer periphery of the refiner disc~ a~ they counter-rotate may drop in a free di~charge.
Of cour3e the nature and placement of the discharge opening will depend on the application of the reflner.
As noted previously, in certain instance~ where the refiner is operated as a pressurized refiner, being appropriately sealed in the well known manner, the ability to con~rol the steam pressure as provided by the lnvention may eliminate the need for the conven- -~
tional ¢ross screw fee~er which i8 normally employed - in delivering material to a preRsurized refiner.
To summarize the benefits of the invention, ~ince the invention eliminates the need for excess water to quench ~te~m that is normally produced in a di~c ref-iner, one can operate the refiner very effect$vely on materials delivered which have a higher consi~tency of ~olids than previously contemplated. A consequence -, . . . . . ...................... .. . .

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: 1045865 of the inventlon in the alternative is that on the one hand one can apply a greater power input to a disc refiner than W~8 previously pos6ible without the usual operational difficulties and with corre~pondingly increasing quality of the end products wh~le on the other hand one can more effectively utilize a lower power input to achleve a higher quality end product than was previou~ly pos~ible.
An obvious additional accomplishment of the invention i8 that it enables a more uniform and controlled feed of the material to be refined and consequently it insures a higher quallty end product. In the process there is a conservation of energy. Obviously, moreover, the invention eliminates overload and stoppage conditions which would normally interfere with a proper infeed of material to be refined.
Much care has been taken to avoid introduction or show-ing of those details of a refiner installation which are not material to an underst~nding of the invention and under such circumstance~, it i~ believed that the invention, it~ ob-~ectives and it~ achievements should be quite clear fromthe foregoing de~cription of an exemplary embodimen~.
From the above description it will be apparent that there i5 thus provided a device of the character described po~sessing th particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construc-tion and arrangement of parts without departing from the principle involved or sacrificlng any of its advantage3.
While in order to comply with the statute the inven- -tion has been described in language more or less specific a~ to ~tructural feature~, it i8 to be understood that the invention is not limited to the ~pecific featurQs shown, but that the mean~ and construction herein dis-closed comprise but one of several modes of putting the invention into effect and the invention is there-fore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A disc refiner including a housing, refiner discs mounted within said housing in paired relation, means de-fining the refining surfaces of said paired discs positioned in opposed, relatively adjacent, and closely spaced re-lation, at least one of said discs being rotatable rel-ative to the other, one of said discs being formed to pro-vide means for the passage therethrough of steam which enters the space between said discs in the operation of the refiner, and means forming an extension of said passage means providing a duct for venting steam from the space be-tween said discs directly to the exterior of said housing.

2. A disc refiner as in Claim 1 wherein means are interposed in said extension to control the amount of steam directed through said duct and from said housing.

3. A disc refiner as in Claim 1 characterized in that said passage means opens to and communicates with an area between said paired discs and their opposed refining sur-faces which constitutes the "eye" of the refiner.

4. A disc refiner as in Claim 1 wherein the one of said paired discs having the means defining its refining surface opposite the refining surface provided on the said disc including said passage means is formed to provide for the material to be refined to pass therethrough and move to the space between said discs in a continuing flow.

5. A disc refiner as in Claim 1 wherein said paired discs comprise a pair of discs each of which is mounted for rotation within said housing and for rotation relative the other, and said passage means opens at one end to a central area of the space provided between said discs.

6. A disc refiner as in Claim 5 wherein each of said discs is mounted on one end of a rotatable shaft, said shafts project from the respective discs in opposite directions and outwardly through apertures in said housing rimmed by sealing means, each of which sealing means provides a bearing surface for the related shaft, and said passage means in said one of said discs includes a plurality of openings which are commonly communicated with said means forming an extension of said passageway.

7. A disc refiner as in Claim 6 wherein said plur-ality of openings as provided in said one of said pair of discs are arranged in adjacent surrounding relation to the shaft to which said one of said pair of discs is mounted.

8. A disc refiner as in Claim 7 characterized in that the other of said pair of discs is formed to also include a plurality of passageways leading from a feed inlet to the refiner to the space between said discs and to provide a flow pattern for the material to be refined to move to and between said refining surfaces provided on said discs.

9. A disc refiner as in Claim 8 characterized in that the ends of said passageways in said discs which communicate with the space between said discs and their refining surfaces are arranged to open to generally the same area of said space.

10. A disc refiner as in Claim 1 characterized in that said paired discs comprise a pair of discs each of which is mounted for rotation within said housing and for rotation relative the other with their refining surfaces in opposed adjacent relation and said passage means opens directly through said one disc, from one face thereof to the other.

11. A disc refiner as in Claim 10 characterized in that said one of said pair of discs is adapted for axial adjustment to change the space between said paired disc refining surfaces as and when required and said means form-ing the extension of said passage means is constructed to accommodate said adjustment while maintaining a directed flow of steam created between the refining surfaces of said discs to and through said passage means and said extension, and one of said passage means and said extension embodies means therein for controlling the flow of steam from between said discs and by way of said passage means and said extension to the exterior of said housing.

12. A disc refiner as in Claim 1 wherein the refin-ing surfaces of said paired discs which are positioned in opposed relatively adjacent and closely spaced relation define therebetween a space a central portion of which pro-vides an eye in which the material to be refined is re-ceived, from which eye the material moves radially outward between the adjacent opposed refining surfaces and dis-charges peripherally thereof into the surrounding interior of said housing, means are provided for supplying the ma-terial to be refined to the said eye, which material will normally embody or be accompanied by liquid inherently heated and converted, at least in part, to steam in the working of said material between said opposed refining sur-faces and said passage means opens to said eye to direct steam therefrom through said duct to the exterior of said housing in bypassing relation to the interior portion of said housing about said discs.

13. A disc refiner according to Claim 12 wherein the disc opposite said disc having therein said passage means is apertured to provide for the passage therethrough to the eye of the refiner of such material as is to be re-fined between said opposed refining surfaces.