|Publication number||US3845909 A|
|Publication date||Nov 5, 1974|
|Filing date||May 3, 1973|
|Priority date||May 10, 1972|
|Also published as||CA983751A, CA983751A1|
|Publication number||US 3845909 A, US 3845909A, US-A-3845909, US3845909 A, US3845909A|
|Original Assignee||Johansson I|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (9), Classifications (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Muted States Patent [1 1 [111 3,845,909
Johansson Nov. 5, 1974 GRINDING APPARATUS FOR VEGETABLE  ABSTRACT MATERIALS The invention relates to a grinding apparatus for vege-  Inventor: lnge J. G. .lohansson, Falkvagen 61, table material which is disintegrated in an interspace 183 50 Taby, Sweden between the opposed grinding surfaces of two grinding discs mounted rotatably in relation to one another  Filed May 1973 within a stationary frame. At least one of the grinding  Appl. N0.: 357,010 discs is carried by a rotatable shaft which in turn is M surrounded concentrically by a screw conveyor for the 30 F A P D t material to be disintegrated in the grinding interspace, 1 M fg g ppslcadlon y a a which conveyor is driven at a substantially lower rotaay 1 we en "6254/72 tional speed than the shaft carrying the grinding disc.
M Disposed between said shaft and the conveyor and be- C(il. 241/6565?! tween the latter and the Stationary frame are stuffing  Field of search 241/66, 65, 67, 247, 250 bxes intended seeping of the apparatus and particles of grinding produce from  References Cited penetrating into thlehspace btettweeli; the shaft and 1th?1 screw conveyor. ese stu mg oxes are supp ie UNITED STATES PATENTS with cooling water under pressure from a common 1,719,784 7/1929 ROSS t 241/67 source in uch a manner that the cooling water first 1,937,788 12/1933 Ross 241/66 X passes through the Stuffing box between the frame and ii zg 2: 55:11 al'm 22 2; the conveyor screw and therefrom to the stuffing box 3:467:323 gngg Asplund ct aim 241/247 between the conveyor screw and the rotatable shaft. 3,717,309 271 973 Luker et al. 241/247 3 Claims, 2 Drawing Figures Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-Howard N. Goldberg 1 1, l l m i i 9 a 5 i a I l 2 v 8 x T A N GRINDING APPARATUS FOR VEGETABLE MATERIALS BACKGROUND OF THE INVENTION The invention relates to a grinding apparatus for vegetable materials of the type comprising two grinding discs mounted rotatably in relation to one another within a stationary frame, at least one of said grinding discs being carried by a rotatable shaft surrounded con centrically and freely by a screw conveyor from an inlet opening in the frame to the grinding surfaces of the discs. This conveyor is driven at a lower number of revolutions per minute than said shaft and serves to feed material to the grinding discs. Grinding apparatus of this kind are disclosed e.g. in the US. Pat. specification No. 3,467,323.
SUMMARY OF THE INVENTION mon external source of pressurized water, such as a pump, while simultaneously preventing fibrous particles from entering into the interspace between the shaft and the screw conveyor inspite of the high pressure prevailing in the zone for feeding the material to be ground into the grinding interspace between the grinding discs. Furthermore, steam is usually supplied to the material to be ground when it is fed from a chute to the inlet opening in order to bring about a softening or steaming of the material.
According to a main feature of the invention water is supplied to the stuffing box pressurized between the shaft and the conveyor which channels in turn communicate with a stationary supply channel from the pressure water source via the stuffing box located between the frame and the conveyor screw.
The object of both stuffing boxes is to prevent steam from escaping due to the over-riding pressure prevailing in the inlet opening and by reason of the over-riding pressure which is produced at the inner side of the grinding surfaces. These conditions arise also if the discharge side of the grinding space is under atmospheric pressure.
By supplying water under over-riding pressure continuous flow of water through the space between the shaft and the screw conveyor in a direction towards the grinding discs is ensured so as to prevent particles of grinding produce from penetrating into said space and thereby establishingfrictional contact with the shaft and the conveyor. It will be apparent that such contact would cause wear and increased power consumption due to thegreat R.P.M. differential between the grinding disc shaft and the screw conveyor. The stuffing box between the screw conveyor and the stationary frame permits a transfer of cooling water to the channels of the rotating conveyor without requiring particular sealing devices.
BRIEF DESCRIPTION OF THE DRAWINGS 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 lateral view, partially in vertical longitudinal section, of a portion of a grinding apparatus embodying the features of the invention.
FIG. 2 is a sectional view on a larger scale of the right hand portion of FIG. 1.
DESCRIPTION OF AN EMBODIMENT OF THE INVENTION outwards from an inner feeding zone 24. The material to be ground is fed to the zone 24 by means of a screw conveyor 26 which is mounted concentrically about the shaft 12 at a spaced distance 28 between the conveyor and the shaft. The conveyor is provided with a suitably helically shaped worm member 30 extending between an inlet opening formed in the stationary frame for the material to be ground and the zone 24. Usually a hopper (not shown) is disposed over the inlet opening 32 and is kept filled with the material to be ground such as wood chips. The screw conveyor 26 may be composed of a cylindrical tube 34 defining the space 28.
0 The outer end of the tube 34 is rigidly secured to a tubular member 36 having a thicker lateral wall. Connected with said tubular member is also a tapering tubular element 38 merging at its narrower end with the tube 34 and located directly below the opening 32. While the shaft 12 may rotate with an R.P.M. of l,800,the R.P.M. of the rotating screw conveyor is substantially less, such as ISO R.P.M. The screw conveyor 26 is mounted in bearings at its external end only, e.g., by means of two ball bearings 40 between which a driving member, such as a gear wheel 42 is mounted for rotating the conveyor.
Disposed between the shaft 12 and the conveyor 26 is a first stuffing box generally denoted 44 and between the conveyor and the stationary frame 10 a second stuffing box generally denoted 46. Both stuffing boxes may be of the same construction and each may comprise a'series of sealing rings 48 made of compressible conventional material and spaced from one another by a distributor or spacing ring 50 or 51, respectively,
made of some harder material, such as metal. Formed stuffing box 46 is rigidly secured to the frame 10 and cooperates with a cylindrical sealing surface formed on the external side of the tubular member 36, and, if desired, provided with a separate lining 66. In the illustrated embodiment the stuffing box 46 is. supportedby an annular element 68 secured to the frame and formed with an annular inner channel 70 which is supplied with cooling water through a channel 72 from a pressure water pump (not shown) connected to the frame. The element 68 has channels 74 equally distributed about the circumference and connecting the channel 70 with the outer annular groove 54 of the distributor ring. From here the pressure water is distributed on both sides to the sealing rings 48 so as to cool said rings and furthermore to make sure that steam which due to the over-riding pressure prevailing in the feeding zone 24 is forced backwards towards the inlet opening 32, is prevented from continuing further to the bearings 40 and to the driving member 42 for the screw conveyor. The stuffing box 44 is located in radial direction inside the bearings 40 and therefore, in axial direction outside the stuffing box 46.
Formed in the annular member 36 of the screw conveyor is a channel system 76 which connects the grooves in the distributor ring 50 of the stuffing box 46 with the grooves in the distributor ring 51 of the stuffing box 44 so that said last-mentioned stuffing box also is supplied with cooling water under over-riding pressure. In addition, this cooling water provides a flow of water through the space 28 between the shaft 12 and the screw conveyor 26 so as to prevent said space from being clogged by ground produce which would cause considerable wear and/or production of heat and increased consumption of power for the rotation of the shaft 12 due to the great R.P.M. differential between the shaft and the conveyor.
According to the invention, cooling water can be fed to the stuffing box 44 inspite of the fact that this stuff ing box is positioned between two parts both of which rotate. The stuffing box 46 also serves the dual purpose of a sealing transfer device for the cooling water hetween the stationary frame and the stationary pressure water source and the rotating screw conveyor.
While a 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:
1. In a grinding apparatus, for vegetable materials, of the type comprising two grinding discs mounted rotatably in relation to one another within a stationary frame, at least one of said grinding discs being carried by a rotatable shaft surrounded concentrically and freely by a screw conveyor for feeding material to be ground from an inlet opening in the frame to the grinding surfaces of the discs, and driven at a lesser number of revolutions per minute than said shaft; the improvement which comprises a stuffing box disposed between the shaft and the conveyor laterally of the inlet opening, said stuffing box being supplied with water under pressure through channels formed in the conveyor which channels in turn communicate with a stationary feeding channel from an external pressure water source over a second stuffing box located between said frame and said conveyor screw.
2. In the apparatus as claimed in claim 1, in which the first-mentioned stuffing box is disposed outside the second-mentioned stufiing box viewed in axial direction.
3. In an apparatus as claimed in claim 2, in which the bearings for supporting the screw conveyor.
|Cited Patent||Filing date||Publication date||Applicant||Title|
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4037801 *||Mar 1, 1976||Jul 26, 1977||Electra Food Machinery, Inc.||Grinding apparatus|
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|US8366114||Feb 5, 2013||Gruner Daron M||Stuffing box cooling system|
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|EP0291410A1 *||May 11, 1988||Nov 17, 1988||C B R Innovation||Method and plant for the extraction of cell water from a basic plant material and/or its by-products|
|U.S. Classification||241/65, 241/247|
|International Classification||B02C7/00, B02C7/06, B02C7/11, D21D1/30, B02C7/16, D21D1/00|
|Cooperative Classification||B02C7/06, D21D1/30|
|European Classification||B02C7/06, D21D1/30|