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Publication numberUS3827644 A
Publication typeGrant
Publication dateAug 6, 1974
Filing dateJul 1, 1971
Priority dateFeb 19, 1969
Publication numberUS 3827644 A, US 3827644A, US-A-3827644, US3827644 A, US3827644A
InventorsJohansson J
Original AssigneeDefibrator Ab
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Grinding apparatus
US 3827644 A
Abstract
A grinding apparatus having a pair of grinding discs, at least one of which discs being rotatable and at least one of the discs being adjustable with respect to the other disc by means of two concentric interengaging screws, the outer screw surrounding the inner screw also engaging a part of the casing carrying the adjustable disc.
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Description  (OCR text may contain errors)

United States Patent 1191 1111 3,827,644 Johansson [4 Aug. 6, 1974 [5 1 GRINDING APPARATUS 1,116,611 11/1914 Nash 241/286 x 1,123,494 1/1915 C 241/259.3 [75] Invent: Johan Inge khansson, 1,135,313 4/1915 1121?, et a1. 241/247 Taby, Sweden 2,743,874 5/1956 Asplynd 241/259.1 x 3,371,873 3/1968 Thomas 241/259.1 X [73] Ass'gnee' 2:23;? Akt'ebolagstockholm 3,625,441 12/1971 54111616111 ..241/259.1x

[22] Filed: July 1, 1971 P E G n Y C J rimary xaminer ranv1 e uster, r. [21] Appl' l59069 Assistant Examiner-Howard N. Goldberg Related Application Data [63] Continuation of Ser. No. 6,112, Jan. 27, 1970,

abandoned. ABSTRACT [30] Forelgn Apphcamn pnomy Data A grinding apparatus having a pair of grinding discs, at Feb. 19, 1969 Sweden 2311/69 least one of which discs being rotatable and at least one of the discs being adjustable with respect to the [52] US. 81. 24l/259.3, 23 32087501; other disc by means of two concentric interengaging Ill. C Screws, the outer Screw Surrounding the inner screw 58 Fleld of Search 241/247, 259.1, 253.3, also engaging a part of the casing carrying the adjust 86 able disc.

[56] References Cited UNITED STATES PATENTS 21 Clauns, 3 Drawing F lgures 932,882 8/1909 Moore et a1. 241/247 PAIENIEDAUB 61 M .3 27 s44 sum 'uFz Figl 28 'INVEWBE GRINDING APPARATUS This is a continuation of Ser. No. 6,1 12, filed Jan. 27, 1970, and now abandoned. I

This invention relates to a grinding apparatus with grinding discs housed in a casing of which discs at least one is rotatable and which discs between themselves form a grinding space for the grinding produce consisting of vegetable or similar material.

More specifically, the invention relates to grinding apparatus of the kind in consideration wherein at least the one grinding disc is formed with two concentrical annular elements. The grinding discs are made so that a gradual disintegration, usuallydenoted as, respectively, defibration and refining of the produce passing through the grinding space is effected. According to the US. Pat. No. 3,684,200 the inner of two concentric annular of disc elements is axially adjustable relatively to the outer one for compensation of the non-uniform wear of the grinding surfaces of the elements. The wear is namely greatest in the inner or primary grinding zone which receives the coarser grinding produce, whereas this latter when entering the outer, secondary grinding zone has already been subjected to a homogenization and a pre-working. I

One main object of the invention is to provide an arrangement which permits adjustment of one grinding discor a portion thereof such as the inner one of two concentric annular elements by actuation from outside while the grinding apparatus is in operation and thus the grinding discs are subjected to the high pressure acting on the grinding produce. This pressure may be createdhydraulically, i.e. in the manner disclosed in the US. Pat. No. 2,891,733. The arrangement shall according to the invention be capable of permitting fine adjustment of the disc or the annular element in axial direction with very high exactness, such as hundredths of one millimeter to attain the most favourable quality of the grinding produce or the highest possible capacity of the grinding apparatus in response to the properties of the grinding produce.

Another object of the invention is to provide an arrangement which is capable of compensating during the operation proper, i.e. any interruption of the operation, for the unavoidable wear on the grinding disc or the annular element, respectively.

According to one main feature of the invention the grinding disc or a suitably radially inner annular element is adjustable by means of two screws disposed concentrically relatively one another and having threads cooperating with one another, that in addition the outer screw and a part carrying said grinding disc or said annular element have threads cooperating with one another, that the two pairs of threads are threaded in the same direction but with different pitches and that one of the screws is rotationally stationary.

In accordance with the invention the threads due to their great pitch can be made so strong that they are capable of withstanding without any disturbing deformation the high axial pressure exerted on the grinding discs, which may amount to many tons per pair of screws. At the same time, the resulting axial displacement of the grinding disc or the annular element becomes little for one part-tum through an angle of the rotatable screw, whereby an exact fine adjustment of the grinding disc or the annular element is rendered possible. According to a particularly advantageous embodiment of the invention a closed space which is connectable to a pressure source for a pressure fluid is provided behind the adjustable grinding disc or annular element. Hereby, the threads can be relieved to a substantial degree from the high axial working pressure during the adjustment operation proper.

Further objects and advantages of the invention will become apparent from the following description, considered in connection with the accompanying drawings, which form part of this specification and of which:

FIG. 1 is a longitudinal sectional view of a portion of a grinding apparatus constructed according to one embodiment of the invention.

FIG. 2 shows two screws and adjacent parts in the same section as in FIG. 1 but in a greater scale.

FIG. 3 is an end view of the casing of the grinding apparatus shown in FIG. 1.

Referring to the drawings, reference numeral 10 denotes the rigid stand of the apparatus which forms a casing which is passed by a rotatable shaft 12 extending from end to end. The shaft 12 carries a grinding disc 14 to which a number of concentrically disposed annular or disc elements, in the present case three elements denoted 16, 18, 22 are connected by means of bolts not shown. Most suitably each of the annular elements 16, 18, 22 is composed of segments. Provided in the centre of the grinding disc 14 is a disc member 20 which has for its purpose to feed the grinding produce introduced by means of a screw conveyor 24, and being e.g. in the form of chips or fibre pulp, in a radially outward direction. A stationary grinding disc is composed of two concentric stator rings 28, 30 supporting grinding disc elements 32 and 34, 36, respectively, each of which also may be composed of segments and between which and the rotatable disc elements 16, 18, 22 a grinding space is formed, which is passed by the grinding produce at an outward direction. The segments of the grinding discs are in known manner formed with ribs and grooves.

The outer stator ring 28 is rigidly secured within the stand 10, whereas the inner stator ring 30 is axially adjustable by means of pairs of screws formed according to the invention. Each of these pairs comprises an outer hollow screw 38, which at its external surface is formed with threads 40 cooperating with the threads 42 formed on an inner flange within a sleeve 44 which is rigidly anchored in an axial recess in the casing or stand 10. An inner screw 48 is formed with an external thread 50 which cooperates with an internal thread 52 formed in the outer screw 38. The screw 48 extends through the sleeve 44 and bears on the stator ring 30. A lock pin 54 is disposed freely movable within the inner screw 48 and its end portion is inserted by screwing it into the stator ring 30. By driving home this lock pin at the outer end thereof the two screws are fixed in predetermined positions relative one another and the stand, respectively. The sleeve 44 is at its interior end bent inwardly towards the screw 48 and forms a guide surface 56 for said screw, which guide surface may house a sealing ring 58.

The threads 40, 42 between the outer retainer screw 38 and the stationary sleeve 44 are preferably rightthreaded and have a relatively great pitch, such as 3 mms per turn. The threads 50, 52 between the two screws 38, 48 are threaded in the same direction, i.e. in the present case also right-threaded, and they have a still greater pitch such as 4 mms per turn. The outer screw 38 is at its outwardly facing end formed with a gear ring 60, which cooperates with an inner gear ring 62 formed on an annular member 64 which is disposed around the circumference of the stand inside a space which widens to recesses 66 at the individual pairs of screws. The annular member 64 is externally mounted in a bearing ring, such as a strip 65 of Teflon (R) or some other material having a low friction coefficient. A number of pairs of screws 38, 48, such as six such pairs, are uniformly spaced about the circumference (see FIG. 3) and the outer screw of each pair is in gear connection with the common annular member 64 which is turned by means of a gear 74. Thus the stator ring 30 when being adjusted to its axial position will be actuated simultaneously by a plurality of screws 48, such as six screws in the illustrated embodiment.

The inner screw 48 has a non-circular, such as hexagonal, outer end portion 68 which fits into a noncircular, such as l2-sided, aperture formed in a plate 72 rigidly attached to the stand 10. Thus the screw 48 cannot be rotated but only be displaced axially.

Pressure oil from a pressure source not shown is supplied to the threads of each pair of screws through a conduit 76, which opens into channels 78, 80 formed in the sleeve 44 and the outer screw 38, respectively. Said screw 38 is also formed with an axial channel 82 for equalization of the pressure in the closed chamber 84 within the sleeve 44, when the screw 38 moves axially and thus changes the volume of said chamber. The chamber 84 is sealed against the surrounding parts by means of sealing rings 86, 88 in addition to the sealing ring 58.

A pressure fluid such as a liquid, preferably water, is supplied from a pressure source not shown through a pipe 90 to a space 92 located at the rear side of the stator ring 30. The stator ring 30 is mounted on the outer stator ring 28 by means of a bearing ring 94 and inwardly on a flange 96 formed on the casing 10 by means of a bearing ring 98. These bearing rings may consist of strips of material having a low friction coefficient, such as Teflon (R) which render the axial displacement of the stator ring 30 more easy. A sealing ring 100 may be provided in addition between the stator rings 28 and 30. By supplying pressure fluid to the space 92 an increased pressure is created therein which is controllable by means of a pressure controller 102 provided in a discharge outlet.

The device operates in the following manner. During operation of the grinding apparatus the grinding produce such as the chips or the fibre pulp is introduced by the conveyor 24 into the space between the two grinding discs within which it is carried radially outwardly, while being disintegrated into fibers or fibriles, respectively. In this operation, the rotating grinding disc 14 is subjected to a strong axial pressure in a direction towards the stationary grinding disc, as will become evident from e.g. the patent specifications referred to above. The pressure acting on the inner stationary stator ring 30 may amount to many tens of tons. According to the invention an axial adjustment of the stator ring or disc 30 can now be effected during operation in response to the desired grinding conditions or for compensation of the wear on the disc elements 34, 36 or 18, 22, respectively, by means of the pairs of screws 38, 48. These pairs of screws are actuated together by means of the gear ring 64, whereby the screw 38 is turned and at the same time displaced axially over a distance for each annular part turn or rotation which corresponds to the pitch of the threads 40, 42. The inner screw 48 is actuated also by said turning movement, but as it cannot rotate, it will be displaced axially only. As the threads are directed in the same direction, and the pitch of the one pair of threads, in the embodiment shown, the pitch of the threads 50, 52 is greater than that of the threads 40, 42, the turning of the outer screws 38 will result in an axial displacement of the inner screw 48 over a distance corresponding to the difference in the pitches of the threads. In this way a fine and correct adjustment of the stator ring 30 is rendered possible while at the same time the threads which transfer the axial pressure from the stator disc 30 to the casing 10 may have high structural strength so as to eliminate any appreciable deformation. It may be pointed out that the adjustment of the grinding surfaces of the grinding discs relative one another must be effected with an exactness of a hundredth of l millimeter, for which reason it is essential that non-controllable deformation shall be avoided of those parts which transfer the axial pressure. The threads between the screws or between one of them at the stationary sleeve 44 are lubricated by means of pressure oil supplied from the conduit 76.

In order to relieve the pairs of screws 38, 48 as much as possible from the high grinding pressure during the adjustment of the stator ring 30, it is advantageous to introduce pressure fluid through the conduit into the space 92. Due to the relatively great surface of the stator disc 30, this pressure fluid need not exert any particularly high pressure to obtain compensation so that the threads during the adjustment operation are relieved entirely or at least to a major extent from the grinding pressure. Also during normal operation of the grinding apparatus a minor overpressure should be maintained in the space 92 to avoid water intermixed with fibres from leaking out from the grinding disc to the screw 38, 48.

While one more or less specific embodiment of the invention has been shown and described, it is to be understood that this is for purpose of illustration only, and that the invention is not to be limited thereby, but its scope is to be determined by the appended claims.

What is claimed is:

l. A grinding apparatus with grinding discs housed in a casing of which discs at least one is rotatable and which discs between themselves form a grinding space for the grinding produce consisting of vegetable or similar material, characterized in that one of the grinding discs is adjustable by means of two screws disposed concentrically relatively one another and having threads cooperating with one another, that in addition the outer screw and a part carrying said grinding disc have threads cooperating with one another, that the two pairs of threads are threaded in the same direction but with different pitches and that one of the screws is rotationally stationary.

2. The grinding apparatus as claimed in claim 1, characterized in that a plurality of concentrically disposed screws are distributed about the circumference of the grinding disc and that the outer screw in each pair is adapted to be turned by a common actuating member.

3. The grinding apparatus of claim 2, characterized in that the common actuating member is a geared ring.

4. The grinding apparatus as claimed in claim 1, characterized in that said inner screw is devised loosely to bear against the grinding disc, but to be locked in relation to the grinding disc by means of a locking member located within the inner screw and actuatable from outside.

5. The grinding apparatus as claimed in claim 1, characterized in that the threads formed between the outer of the two concentrically disposed screws and the stationary part have a smaller pitch than the threads existing between the screws.

6. The grinding apparatus as claimed in claim 1, characterized in that the two pairs of threads are rightthreaded.

7. The grinding apparatus as claimed in claim 2, characterized in that the outer screws in each pair of screws have a gearing ring which cooperates with said geared ring and at the same time is actuated by said geared ring.

8. The grinding apparatus as claimed in claim 1, characterized in that disposed behind the adjustable grinding disc is a closed space which is connectable to a pressure source for a pressure fluid.

9. The grinding apparatus as claimed in claim 8, characterized in that arranged in a pressure fluid conduit connected to the space is a pressure controller for determining the magnitude of the relieve pressure acting on the grinding disc.

10. A grinding apparatus with grinding discs housed in a casing in which discs at least one is rotatable and which discs between themselves form a grinding space for the grinding produce consisting of vegetable or similar material, at least one grinding disc being formed with two concentrical annular elements, characterized in that one of said annular elements is adjustable by means of two screws disposed concentrically relatively one another and having threads cooperating with one another, that in addition the outer screw and a part carrying said annular element have threads cooperating with one another, that the two pairs of threads are threaded in the same direction but with different pitches and that one of the screws is rotationally stationary.

11. The grinding apparatus as claimed in claim 10, characterized in that the adjustable annular element is the radially inner one.

12. The grinding apparatus as claimed in claim 10, characterized in that a plurality of concentrically disposed screws are distributed about the circumference of the annular element and that the outer screw in each pair is adapted to be turned by a common actuating member.

13. The grinding apparatus as claimed in claim 12, characterized in that the common actuating member is a geared ring.

ing member located within the inner screw and actuatable from outside.

15. The grinding apparatus as claimed in claim 1, characterized in that the threads formed between the outer of the two concentrically disposed screws and the stationary part have a minor pitch than the threads existing between the screws.

16. The grinding apparatus as claimed in claim 1, characterized in that the two pairs of threads are rightthreaded.

17. The grinding apparatus as claimed in claim 12, characterized in that the outer screws in each pair of screws have a gearing ring which cooperates with said geared ring and at the same time is actuated by said geared ring.

l8.-The grinding apparatus as claimed in claim 1, characterized in that disposed behind the adjustable annular element is a closed space which is connectable to a pressure source for a pressure fluid.

19. The grinding apparatus as claimed in claim 18, characterized in that arranged in a pressure fluid conduit connected to the space is a pressure controller for determining the magnitude of the relieve pressure acting on the annular element.

20. A grinding apparatus having a pair of grinding discs forming between them a grinding space for the material to be ground of which discs at least one is rotatable, and at least one of which discs is provided with two concentrical annular elements, characterized in that one of said annular elements is adjustable by screw means including interengaging threads, a closed space being disposed behind said adjustable annular element, said space being connectable to a pressure source for a pressure fluid, so as to relieve said threads from the grinding pressure between the grinding discs during the adjustment of the annular elements.

21. A grinding apparatus having a pair of grinding discs forming between them a grinding space for the material to be ground of which discs at least one is rotatable, and at least one of which discs is provided with two concentrical annular elements, characterized in that one of said annular elements is adustable by means including two concentrical interengaging screws, the outer surrounding screw also having threads engaging a screw threaded part of the casing carrying said annular element, and a closed space behind said annular element which is adapted to be connected to a source for supplying fluid under pressure whereby to release said threads from the grinding pressure between the grinding discs during adjustment of the annular element.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US932882 *Oct 3, 1908Aug 31, 1909William Forrester MooreGrain-grinding machine.
US1116611 *May 23, 1912Nov 10, 1914Atlanta Utility WorksCotton-seed huller.
US1123494 *Apr 2, 1914Jan 5, 1915 Grinding-machine.
US1135313 *Oct 27, 1913Apr 13, 1915William Forrester MooreGrain-grinding machine.
US2743874 *Jul 19, 1952May 1, 1956Arthur Asplund Arne JohanDisk type grinding apparatus for fibrous materials
US3371873 *Mar 24, 1966Mar 5, 1968Keith V. ThomasRefining apparatus
US3625441 *Sep 29, 1969Dec 7, 1971Beloit CorpCounterrotating refiner
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4114818 *Apr 14, 1977Sep 19, 1978Enso-Gutzeit OsakeyhtioDisk refiner
US5509610 *Jan 27, 1994Apr 23, 1996Gibbco, Inc.Centrifugal chopping and grinding apparatus
US5531385 *May 7, 1993Jul 2, 1996Witsken; AnthonyApparatus and methods for wet grinding
US5707016 *Jul 1, 1996Jan 13, 1998Witsken; AnthonyApparatus and methods for wet grinding
US7694902Jun 8, 2005Apr 13, 2010Kadant Black Clawson Inc.Self-aligning and actively compensating refiner stator plate system
WO2002047822A2 *Nov 28, 2001Jun 20, 2002J & L Fiber Services IncAdjustable refiner plate
WO2006043162A2 *Oct 21, 2005Apr 27, 2006Welldone Weartec N VCrushing element and mills with grinding bodies, mixers, extruders and a pressing worm provided with said crushing elements
Classifications
U.S. Classification241/259.3, 241/285.1
International ClassificationB02C7/14, B02C7/00
Cooperative ClassificationB02C7/14
European ClassificationB02C7/14