US3762657A - Continuously operating agitator ball mills - Google Patents

Continuously operating agitator ball mills Download PDF

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Publication number
US3762657A
US3762657A US00254644A US3762657DA US3762657A US 3762657 A US3762657 A US 3762657A US 00254644 A US00254644 A US 00254644A US 3762657D A US3762657D A US 3762657DA US 3762657 A US3762657 A US 3762657A
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US
United States
Prior art keywords
shaft
ball mill
agitator
agitator ball
gap
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00254644A
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English (en)
Inventor
Martin K Schieritz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Willy A Bachofen AG
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Willy A Bachofen AG
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Filing date
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Application filed by Willy A Bachofen AG filed Critical Willy A Bachofen AG
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Publication of US3762657A publication Critical patent/US3762657A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/16—Mills in which a fixed container houses stirring means tumbling the charge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/18—Details
    • B02C17/1815—Cooling or heating devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C25/00—Control arrangements specially adapted for crushing or disintegrating

Definitions

  • the position of the second annular member along the shaft is determined by a demountable spacer member to provide coarse adjustment of the width of a gap defined between mutually facing axial surfaces of the first and second annular members. Coolant is applied to the stator to cause controllable axial contraction of the stator relative to the shaft. This relative contraction increases the width of the gap and thus provides a fine adjustment of the width, so as to prevent grinding bodies from passing through it, whilst permitting material ground in the mill by the bodies to pass through the gap and thereby become separated from the grinding bodms.
  • the present invention relates to an agitator ball mill for extremely fine grinding or the disintegration of extremely small particles.
  • Ball mills are known wherein in a grinding recepta' cle, grinding bodies, in most cases glass balls, are set in motion by way of an agitator shaft. The energy imparted to the balls enables them to comminute the material to be ground through the effect of impact and shearing force. It is self-evident, in this connection, that the size of the grinding bodies must be dependent upon the size of the particles in the starting product. The smaller the particle size in the grinding stock, the smaller, also, must be the diameter of the grinding bodres.
  • An object of the present invention is therefore to create a ball mill of the type mentioned initially, in which the adverse side effects produced by cooling are significantly reduced.
  • an agitator ball mill comprising a generally annular stator assembly including a first annular member, a rotor shaft mounted co-axially with respect to the stator assembly, a second annular member mounted on the rotor shaft to rotate therewith, mutually facing axial surfaces of the first and second annular members defining therebetwee'n a gap, a demountable spacer member axially locating the second annular member relative to the rotor shaft, and means for applying a cooling medium to the stator assembly to cause the latter to contract axially relative to the rotor shaft and thereby to increase the width of the gap, so that in use the width of the gap may be so adjusted as to prevent grinding bodies from passing through it whilst permitting material ground in the mill by the bodies to pass through the gap and thereby become separated from the grinding bodies.
  • the rotor in this connection it is advantageous for the rotor to be connected co-axially with an agitator shaft.
  • Ballbearings especially double ball-bearings, are suitable for the precise mounting of the agitator shaft.
  • the two surface portions between which the gap is defined can consist of hard metal or some other wear-resistant material.
  • a bearing body 4 which is essentially a hollow cylinder, is fixed to the frame 1 by bolts 2 and a support ring 3.
  • a part 5 of the bearing body 4 which narrows by steps from the outside extends through the wall of the frame 1 through a co-axial opening la in the frame.
  • a concentric sleeve 6 is pushed over the bearing body 4.
  • the internal diameter of this sleeve is not constant, however, but at the free end of the 'sleeveit corresonds to the external diameter of the bearing body 4 at this point and likewise at the other end, where the sleeve 6 is also sunk in an annular groove lb in the frame.
  • the free end faces of the bearing body 4 and the sleeve 6 lie in one plane.
  • Formed in the bearing surfaces of the sleeve on the bearing body are two grooves 6a and 6b which accommodate in each case an O-ring 7 and 8 which seal the two parts off from one another.
  • a double ball bearing 12 is fixed by its outer ball race 12a.
  • the inner wall of the bearing body 4 has two graduations, their end faces acting as supports for two rings 13 and 14 which are in contact with the two end faces of the ball-bearing 12, thereby holding the latter in position.
  • the ring 13 is fixed to the bearing body 4 by means of screws 13a.
  • the inner ball race 12b of the ball-bearing 12 is a snug fit on a hollow shaft 15 which extends right through the bearing body and projects beyond it at both ends.
  • the hollow shaft 15 has a torus 115a which acts as a stop for the inner ball race 12b. On its other side the latter is secured against axial displacement by means of a spacer sleeve 16 mounted co-axially on the hollow shaft 15. The inner space of the double ball-bearing is protected by means of two cover rings ll'7a and 17b from the entrance of foreign bodies.
  • a further ball-bearing 18a, 18b At the other end of the bearing body, that is to say in its sector 5, is fitted a further ball-bearing 18a, 18b.
  • the outer ball race 18a is fitted into the somewhat widened inner space of the part 5, whereas the inner ball race rests on the hollow shaft 115 and is braced on the end face of the spacer sleeve 16 on the side facing the double ball-bearing.
  • Fixed on the end of the hollow shaft 15 projecting from the ball-bearing 18 is a fourstep pulley 19 which is connected with the hollow shaft so as to be rigid in respect of rotation by means of a slot-and-key connection 39b.
  • the end face of the hub 19a of the pulley, which faces the frame l, is supported on the inner ball race 18b of the ball-bearing 18a, Mb.
  • the pulley 19 is driven by a motor 652 which is represented'only diagrammatically on the drawing.
  • annular fixing disc 20 Fitted on the common end face of the two parts 4 and 6 is an annular fixing disc 20 which is attached to the bearing body by screws 211. For this purpose threaded bushes 2111 are let into the bearing body to ensure greater stability and precision of the joint.
  • the fixing disc To make it possible for the fixing disc to be fixed in the correct position the sleeve 6 is provided with a centering pin 22 which engages in a corresponding hole in the disc 20, thus defining its position clearly.
  • the disc 20 has a bigger diameter than the sleeve 6.
  • the annular part of the disc projecting beyond the latter has drilled holes 23 to accommodate bolts 23a.
  • a flange 24 of substantially hollow cylindrical shape, is secured to the fixing disc 20, its internal diameter in its portion facing the double ball-bearing corresponding approximately to the mid-line diameter of the latter and in its other part approximately to the external diameter of the ball-bearing 12.
  • a graduated constriction 24a on which is supported by its broad sides an annular lip seal 25a.
  • Adjacent one end face of the lap 25a is a ball spacer 26 which makes contact by its outer wall with the inner wall of the flange 24.
  • a second lip seal 25b adjoins the ball spacer 26, or as a substitute for this a blank flange with an elastic ring 27a adjoining it.
  • a thrust collar 27 rests against the ring 27a by the inner portion of one graduated end face and against the end face of the flange 24 facing the fixing disc 20 by the outer portion and is connected with the flange by means of screws 28.
  • the hollow shaft 15 extends as far as the constriction 24a of the flange 24. in the region beyond the torus 15a, a shaft protecting sleeve 29 is fitted tightly on the shaft.
  • the sleeve 29 consists of polished hard metal and projects slightly over the end of the hollow shaft 15.
  • the lips of the two sealing rings 25a and 25b rest against the smooth surface of the sleeve 29.
  • a disc 30 is mounted on the hollow shaft 15 in such a way that its end face is supported on the shaft protecting sleeve 29 on one side and on the torus on the other.
  • this disc 30 is to throw any grinding stock which may pass through the lip seal radially outwards, where it can run off on the inner wall of the bearing body 4 and can drain away into the outer space of the mill through an opening 31 formed in the body 4 and in the sleeve 6. This provides simultaneously the possibility of controlling the state of the lip seals 25a and 25b.
  • a further function of the disc 30 consists in the fact that with it it is possible to compensate for all the longitudinal dimensions of those machine parts which cannot be produced with the precision required for adjustment of the gap.
  • these bores 32a and 32b can also be utilized for the intake and outlet respectively of a cooling medium which cools the area of the shaft protecting sleeve 29, or the hollow shaft 15, between the two seals where heat is generated through the friction.
  • a bore 34a Opening into the inwardly widened space'35 of the flange 24 from above is a bore 34a which passes, towards the outside, into a connecting nipple 34 for the removal of the ground material.
  • the free end face of the flange 2 4 has a bush-type projection 24b into which there is let a groove 24c in which, in turn, an O-ring 36 is inserted.
  • a bearing ring 37 On this projection 24b and with one end face in contact with the flange 24 a bearing ring 37, which is sealed off by the O-ring 36, is fitted, with an annular groove 38 in the mid-line of its free end face. Inserted in the groove 38 is a further O-ring 39.
  • the bearing ring 37 acts as a mating pressure face for the grinding receptacle 40 which is substantially cylindrical and open at one end face, its opening edge resting tightly on the O-ring 39 and on the bearing ring 37.
  • the support for the receptacle is constituted by a clamping device which is not shown in the drawing. It acts on the closed end of the receptacle and presses it against the bearing ring.
  • the receptacle is double-walled and is provided with an inlet and an outlet for a cooling liquid which'ca n be introduced between its two walls, these also not being shown in the drawing.
  • the actual agitator shaft 41 Mounted inside the hollow shaft 15 is the actual agitator shaft 41, with quite a small amount of play. At one end it projects somewhat beyond the hollow shaft and the pulley 19 and is likewise connected in a rotationally fixed manner by way of the slot-and-key connection 1% with the hollow shaft, or the pulley l9. Screwed on to the projecting portion is a tension nut 42 which is supported on the end face of the hub of the pulley.
  • the other end of the agitator shaft 41 projects from the flange 24 to just before the bottom of the grinding vessel 40 and there has a disc-like widened end 411a.
  • a distance piece 43 Adjacent to the shaft protecting sleeve 29 on the agitator shaft there is mounted a distance piece 43 which widens out conically in the direction of the end of the agitator shaft. Formed in its end face which is in contact with the shaft protecting sleeve is a recess of the diameter ofthe hollow shaft, in which is inserted a sealing sleeve 44 which lies with its other end between the shaft protecting sleeve and the agitator shaft and is supported on the free end of the hollow shaft 15. Consequently the distance piece 43 is tightly connected with the shaft protecting sleeve 29.
  • Thefree end face of the ring 45 is the foremost front surface on the flange 24 and it constitutes the fixed wall of the gap 46.
  • the second wall of the gap is formed by a further hard metal ring 47 which is fixed to a bracket 48 which, in turn, is precisely situated on the agitator shaft.
  • the end face of the ring 47 constituting the second wall of the gap 46 has a smaller internal diameter than the external diameter of the distance piece, so that the latter supports the ring 47by its free end face, presses it against the bracket 48 and thus holds it firmly and, through the longitudinal dimension of the distance piece 43, keeps it at a precisely defined distance from the ring 45.
  • the ring 47 together with the remaining rotatable parts, constitutes the rotor assembly.
  • the entire agitator shaft 41 can be withdrawn from the hollow shaft 15 after the grinding receptacle 40 has been taken off.
  • the individual parts such as for example the'sealing sleeve 44, the distance piece 43, the bracket 48 with the ring 47, the small tubes 49 and the agitator disc 50, can be pulled off the agitator shaft and, if necessary or desired, exchanged for new parts orparts of some other materials. This offers advantages from the point of cleaning techniques, permits a quicker exchange of worn parts, and facilitates the adaptation to special conditions which may be required.
  • the mill can be adapted excellently to any existing conditions.
  • the necessary size of grinding body for the purpose e.g. 0.1 millimetre is first determined. Then, using the rule of thumb mentioned initially, a gap width of approximately 0.02 0.03 millimetre is obtained.
  • a gap width is defined with a slightly smaller value. This value depends, in fact, upon the type of cooling to be employed. If, for example, cooling is to be by tap water a distance piece must be inserted which produces a gap width of 0.02 millimetre at room temperature. If, however, cooling is effected with a special cooling brine at a temperature of20C, a distance piece must be used which reduces the gap width to zero at room temperature.
  • the agitator shaft is then inserted in the hollow shaft and tightened up by means of the tension nut.
  • the cool ing liquid is then introduced into the space 11 between the bearing body and the sleeve 6 and for a definite span of time this part only is cooled and not simultaneously the grinding vessel, into which meanwhile the grinding bodies can be loaded and the suspension with the bacteria introduced by means of a pump.
  • the increase in the width of the gap 46 amounts to approximately 0.005 millimetres and with cooling brine to about 0.03 millimetres, which in conjunction with the distance piece being used at any given time gives a gap width of 0.025 or 0.03 millimetres as the case may be.
  • the suspension is pumped into the vessel through a filler neck 40a and there disintegrated (broken up) in a continuous process. Then, when the grinding bodies have been separated off, it leaves the grinding vessel through the nipple 34.
  • the width of the gap can be adapted to exisiting circumstances in the simplest way by means of inter-changeable distance pieces.
  • the fine adjustment of the gap width by means of the temperature of the cooling medium for the flange on which the fixed wall of the gap is fitted, offers the advantage that it can be carried out conveniently and above all in the most precise manner possible.
  • thermo-switch 61 By fitting an additional safety device, for example a temperature sensor 60 with a thermo-switch 61, it is possible to keep the temperature of the cooling medium and hence also the gap width under constant supervision and in the event of an unforeseen rise in the temperature of the cooling medium the two wallsof the gap can be prevented from becoming jammed, since this danger can be detected promptly and eliminated either manually or automatically by way of the stopping of the driving motor 62.
  • a generally annular stator assembly including a first annular member
  • An agitator ball mill as defined in claim 4 comprising at least one agitator member mounted on said inner shaft to rotate therewith.
  • each said bearing means comprises a ball bearing assembly provided with an inner ball race and an outer ball race.
  • An agitator ball mill as defined in claim 1, comprising temperature sensing means responsive to the temperature of the cooling medium exceeding a predetermined value to automatically disable drive means for rotating said rotor shaft.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
US00254644A 1972-03-01 1972-05-18 Continuously operating agitator ball mills Expired - Lifetime US3762657A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH294472A CH550024A (de) 1972-03-01 1972-03-01 Kontinuierlich arbeitende ruehrwerk-kugelmuehle.

Publications (1)

Publication Number Publication Date
US3762657A true US3762657A (en) 1973-10-02

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ID=4245137

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Application Number Title Priority Date Filing Date
US00254644A Expired - Lifetime US3762657A (en) 1972-03-01 1972-05-18 Continuously operating agitator ball mills

Country Status (17)

Country Link
US (1) US3762657A (xx)
JP (1) JPS5635509B2 (xx)
AR (1) AR197121A1 (xx)
AU (1) AU465327B2 (xx)
BE (1) BE782278A (xx)
CH (1) CH550024A (xx)
CS (1) CS162791B2 (xx)
DD (1) DD102596A5 (xx)
DE (1) DE2215790C2 (xx)
ES (1) ES411920A1 (xx)
FR (1) FR2174127B1 (xx)
GB (1) GB1325835A (xx)
HU (1) HU166540B (xx)
IT (1) IT977906B (xx)
NL (1) NL7204666A (xx)
SE (1) SE398305B (xx)
ZA (1) ZA731391B (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121776A (en) * 1976-07-20 1978-10-24 Carlos Oliver Pujol Cooled horizontal-axle grinder
US20110000993A1 (en) * 2009-07-06 2011-01-06 Willy A. Bachofen Ag Agitator ball mill
US20110121115A1 (en) * 2009-11-25 2011-05-26 Willy A. Bachofen Ag Agitator ball mill
CN113083445A (zh) * 2021-03-16 2021-07-09 山东省冶金设计院股份有限公司 一种同步粉磨烘干方法及系统

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2745355C2 (de) * 1977-10-08 1993-06-24 Gebrüder Netzsch, Maschinenfabrik GmbH & Co, 8672 Selb Rührwerksmühle
DE3245825C2 (de) * 1982-12-10 1994-01-27 Buehler Ag Geb Rührwerksmühle
IT1208868B (it) * 1987-04-15 1989-07-10 Antonio Pelizza Mulino verticale a microsfere perfezionato particolarmente per la dispersione di pigmenti in veicolo fluido
ES2030618A6 (es) * 1990-10-31 1992-11-01 Oliver & Battle Sa Molino para triturar y desaglomerar solidos predispersados en liquidos.
ES2031789A6 (es) * 1991-06-27 1992-12-16 Oliver & Battle Sa Mejoras en el objeto de la patente principal n{ 9002766 por molino para triturar y desaglomerar solidos predispersados en liquidos.
CN102814216B (zh) * 2012-08-26 2015-01-21 向小月 双轴研磨系统
CN114260072B (zh) * 2022-01-22 2022-08-23 广东鸿凯智能科技有限公司 一种高散热性的锂电池用纳米级原料研磨装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1937788A (en) * 1927-12-01 1933-12-05 Oscar A Ross Colloidal mill and system of control therefor
US2083171A (en) * 1930-08-27 1937-06-08 Geneva Processes Inc Adjustable colloid mill stator
US2403914A (en) * 1942-04-07 1946-07-16 Eppenbach Vertical mill

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1937788A (en) * 1927-12-01 1933-12-05 Oscar A Ross Colloidal mill and system of control therefor
US2083171A (en) * 1930-08-27 1937-06-08 Geneva Processes Inc Adjustable colloid mill stator
US2403914A (en) * 1942-04-07 1946-07-16 Eppenbach Vertical mill

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121776A (en) * 1976-07-20 1978-10-24 Carlos Oliver Pujol Cooled horizontal-axle grinder
US20110000993A1 (en) * 2009-07-06 2011-01-06 Willy A. Bachofen Ag Agitator ball mill
US8118247B2 (en) 2009-07-06 2012-02-21 Willy A. Bachofen Ag Agitator ball mill
US20110121115A1 (en) * 2009-11-25 2011-05-26 Willy A. Bachofen Ag Agitator ball mill
CN113083445A (zh) * 2021-03-16 2021-07-09 山东省冶金设计院股份有限公司 一种同步粉磨烘干方法及系统

Also Published As

Publication number Publication date
GB1325835A (en) 1973-08-08
HU166540B (xx) 1975-04-28
AU5237873A (en) 1974-08-22
BE782278A (fr) 1972-08-16
DE2215790C2 (de) 1974-02-07
AR197121A1 (es) 1974-03-15
CS162791B2 (xx) 1975-07-15
JPS48104149A (xx) 1973-12-27
JPS5635509B2 (xx) 1981-08-18
SE398305B (sv) 1977-12-19
FR2174127A1 (xx) 1973-10-12
DE2215790B1 (de) 1973-06-20
FR2174127B1 (xx) 1977-02-04
IT977906B (it) 1974-09-20
NL7204666A (xx) 1973-09-04
DD102596A5 (xx) 1973-12-20
ES411920A1 (es) 1976-01-01
AU465327B2 (en) 1975-09-25
ZA731391B (en) 1973-12-19
CH550024A (de) 1974-06-14

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