DE2634835A1 - AGITATING BALL MILL WITH A GRINDING CHAMBER AND A CHANNEL FOR A COOLING OR HEATING MEDIUM - Google Patents

Description

oipi -W J. scnMiDT-EVERS Dr.Kö / ko

8 MUNICH 22. Steinsdoibtr. 10

Willy A. Bachofen , Basel (Switzerland) _f utengasse 15

Patent application

Agitator ball mill with a grinding chamber and a channel for a cooling or heating medium

The invention relates to an agitator ball mill with a grinding chamber with a cylindrical chamber wall and a A channel running helically along the outer surface of the chamber wall for cooling or heating serving fluid, wherein the boundary surface of the channel facing the interior of the grinding chamber through the outer surface of the chamber wall is formed.

Agitator ball mills have a grinding chamber in which an agitator is arranged, which rotates during operation. As a result, the balls contained in the grinding chamber are set in motion, so that they are the ones to be ground Use impact and shear forces to shred the material that is also in the grinding chamber.

Ball mills are used for the production of dyes or for the disintegration of microorganisms used for enzyme recovery. During the grinding process

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kinetic energy converted into heat. Furthermore, chemical reactions can take place in which additionally Heat is released. It is often very important that the temperature of the material to be ground is kept as possible when grinding is increased little. In these cases, the grinding chamber must be cooled. On the other hand, it can sometimes it may also be necessary to additionally heat the grinding chamber.

In a previously known agitator ball mill, the grinding chamber wall is encased by a cylindrical jacket which, together with it, has a circular cross-section Limited space. The coat is at two diametrically opposite points with a series of Provided through openings. Through one of these rows of through openings a coolant, such as tap water, is supplied to the space in between. This flows through then the interspace and exits the interspace again through the other row of through-openings.

In this known ball mill, however, the grinding chamber is not cooled to the same degree everywhere, so that the Temperature can be relatively high at certain points in the grinding chamber. So that not individual parts of the If the ground material is heated inadmissibly, a large coolant flow must be used.

Although not in ball mills, it is known from other applications to have chambers to be cooled with cooling coils to provide, which run helically along the outer surface of the chamber wall. Acquaintance Cooling coils of this type are formed by round or rectangular tubes that are attached to the chamber wall are welded or soldered on. However, this design has the disadvantage that between the pipe and the chamber wall has a relatively large heat transfer resistance, which increases the efficiency reduced.

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It is now also already known, instead of pipes, approximately semicircular chins in this way on a chamber wall To be welded or soldered on so that they form a helical channel together with the chamber wall. Its boundary surface facing the interior of the chamber is then directly passed through the outer surface of the Chamber wall formed so that the coolant has direct contact with the chamber wall. This can reduce the contact resistance between the coolant and the chamber wall can be lowered. So that the two edges of a gutter can be soldered or welded tightly, must be between the successive turns of the gutter there must be a gap. This has the consequence that chamber wall sections between the adjacent channel turns are present that are not flowed around by the coolant. So can also with this training cooling of the coolant channels is not completely uniform can be achieved. In addition, the tight welding or soldering of the channel requires a fairly large one Expenditure of time and must be carried out with great care by a qualified specialist.

The present invention is based on the object of creating an agitator ball mill in which the whole chamber with. low fluid flow can be evenly cooled or heated.

Starting from the chamber last described above, this task is performed by an agitator ball mill of the type mentioned in the introduction, which is characterized according to the invention in that the dem Inside the grinding chamber facing away from the boundary surface of the channel by a shell coaxial to the chamber wall is formed and that the two lateral boundaries of the channel by the two side surfaces of two successive helical turns of a single partition wall are formed.

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Various comparative tests were carried out in which previously known agitator ball mills were compared with agitator ball mills according to the invention. Tap water was used as the fluid for cooling. It has been shown that the temperature was 5O ⁰ C, for example in the grinding chamber under otherwise identical conditions and in particular in cooling with the same amount of fluid at a known ball mill, for example, 60 C and at an inventive ball mill. Further tests have shown that the temperature during cooling in the grinding chamber in the ball mill according to the invention can be kept at a value which is approximately 5 to 20 lower than in the case of the previously known designs.

The subject matter of the invention will now be explained with reference to the exemplary embodiments shown in the drawing. In the drawing show

FIG. 1 shows a longitudinal section through an agitator ball mill with a grinding chamber surrounding the grinding chamber, helical duct,

FIG. 2 shows a detail from FIG. 1, on a larger scale,

FIG. 3 shows a variant of an agitator ball mill, and

FIG. 4 shows a section of the wall and the jacket of a further variant of a grinding chamber.

The agitator ball mill, which is only partially shown in FIG. 1, has a frame, of which only the body 1 is shown. The latter has a sleeve-shaped

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Part la, which is followed by a splash Ib at the free end. On this, the ring 3 is designated as a whole with 2 by means of screws (not shown) Grinding chamber attached.

This has a metallic cylindrical chamber wall 4, which is tightly attached to the metallic ring 3, for example is welded on. At the other end, the chamber wall 4 is provided with a tightly welded ring 5.

As can be seen particularly clearly from FIG. 2, the ring 3 has a cylindrical neck 3a which is provided at its free end with a radially outwardly projecting collar 3b. On the latter is a metallic jacket 6 tightly fastened, namely welded or soldered on. At the other end is the coat 6 attached to the ring 5 in a corresponding manner.

The jacket 6 is also cylindrical and coaxial to the chamber wall 4. It envelops the latter and delimits it you together have a circular cross-section gap. The outer surface 4a of the chamber wall 4 is provided with a helical groove 4b. In the groove 4b is a rectangular cross-section from Metal existing band is used, which forms a spiral-shaped partition wall 7. The Indian FIG. 2 visible end section 7a and the other end section of the band forming the partition wall 7 are on attached to the chamber wall 4, namely welded or soldered. The outer surface 4a of the chamber wall 4, the Inner surface 6a of the jacket 6 and the two side surfaces 7b and 7c of the partition wall 7 together delimit one helical channel 8. The two lateral boundaries of the channel 8 are so, apart from

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the channel ends, formed in each helical turn by the two side surfaces 7b, 7c of "two successive helical turns of the same dividing wall 7. Between two successive helical turns of the channel 8 there is only the dividing wall 7 and no further space available.' ^:

At the edge on the left in FIG of the jacket 6 there is an inlet ^ connecting piece 9 ^ which opens into the beginning of the channel 8. The other end of the channel 9 is provided with an outlet connector 10 tied together. Through the inlet nozzle 9 can the channel 8 a liquid or possibly gaseous fluid can be supplied to the chamber wall cool or warm.

The height of the partition wall 4 is dimensioned such that the partition wall rests reasonably tightly both on the chamber wall 4 and on the casing 6. The partition wall 7 does not have to be completely tight, but it must fit so tightly that at least half of the fluid follows the Söhräubenlinieh turns and not "parallel to the axis of the grinding chamber between the edges of the partition wall 7 and the chamber wall 4 or the Sheath 6 flows through - ^: ' ^: '

When manufacturing the grinding chamber 2, the chamber wall 4 is first welded or soldered to the ring 3; The channel 8 can be approximately made so that one for the preparation ^of: using an elastic "deformable band separation Wähd 7 and wraps from this a helical spring, the Interior

ORlQlNAL INSPECTED

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diameter slightly smaller than the diameter of the outer surface 4a is. When the resilient band is then pushed onto the chamber wall 4, its turns engage under it Bias in the groove 4b and rest on the bottom. Then the ends of the partition wall 7 forming band welded to the chamber wall. The jacket 6 is expediently made so that its inside diameter is slightly smaller than the outside diameter the partition wall 7 · The jacket 6 can then be heated so that it expands and in a warm state be pushed over the partition wall 7. The ring 5 is then pushed onto the chamber wall 4 and welded or soldered to this. Furthermore, the jacket 6 can now be attached to the two rings 3 and 5 be welded or soldered on. When the jacket 6 has cooled down to ambient temperature again, lies he under bias on the partition wall 7 on. In this way, despite any manufacturing inaccuracies that may exist a sufficient tightness can be achieved.

The nozzles 9 and 10 can now be soldered in or welded in and if necessary connected to the ring 3 or 5 by stiffening elements. Furthermore can the jacket 6 can additionally be covered with an insulating cover (not shown) for thermal insulation. Of course, you can also use a protective coat be provided, which together with the coat ί a cavity 1> delimits.

On ring 5 is “in intermediate ring 11 and” in flange 12 screwed the grinding chamber to dk »« at aioh right at the end. The flange 12 is with an input connection 13, you * «* 4 · η that ^ Good to be ground can be supplied.

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In the sleeve-shaped part la is by means of a ball bearing 14 and a further, no longer visible bearing, a shaft 15 is rotatably mounted. Its free end protrudes into the interior of the grinding chamber 2 and carries a stirring element 16 with stirring disks 17. These are with incisions and sliding surfaces are provided in order to stir the balls contained in the grinding chamber during operation.

A gap separator is arranged at the left end of the grinding chamber. This has an annular stator 18 which is fastened to a ring 19. The latter is clamped between the flange Ib and the ring 3. The gap separator also has a rotor 20 which is seated on the shaft 15. The stator 18 and the rotor together delimit an annular gap which is dimensioned such that the ground material flows out of the grinding chamber, but the balls used for grinding are retained. On the left side of the gap separator there is an output connection 21 which is provided with a tap 22 and through which the ground material can be removed. At its left end, which is no longer visible in FIG. 1, the shaft 15 is connected to a drive motor via a gear. In the area of the gap separator, there are also coolant connections, one of which is visible and designated by 23. These allow certain parts of the gap separator to be cooled. For the design and mode of operation of the gap separator, reference is made, for example, to the Swiss fatentsehrift iir .. 55 © OS ¹ J or the number * 3? £ 2 € 57.

When operating <ier agitator ball mill, the grinding chamber 2 through cent. the Jinput connection in liquid form paying good fed. It can be about a liquid with bacteria that is carefully extracted

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an enzyme are to be broken down. The one in the grinding chamber 2 existing balls are moved by the agitator 16 and crush the material to be ground by shocks and shear forces. This releases heat. The channel 8 is now used for cooling during operation Fluid, such as tap water, flows through it. Since the 'fluid inevitably runs along the whole Channel 8 must flow, cooling of the entire chamber wall 4 is guaranteed. As the fluid, apart from the groove 4b filled by the partition wall 7, the entire outer surface 4a of the chamber wall 4 directly touches, there is a good heat exchange between the chamber wall 4 and the fluid and thereby a high degree of efficiency and uniform cooling of the entire chamber wall 4. "So you can use a relatively A small amount of fluid means that the material to be ground is nowhere in the grinding chamber 2 exceeds a specified temperature limit. It should also be noted that the partition wall 7, which is yes is also in thermally conductive connection with the chamber wall 4., Of course, also contributes to the heat exchange between the chamber wall and the fluid.

Another embodiment of an agitator ball mill is shown in FIG. This is provided with a frame 101 and a grinding chamber 102. The latter has a chamber wall 104 and a jacket 106. On the latter a ring is at both ends welded or Ϊ05 103 * The chamber wall is LO4. Both ends of Aüsseriseite äüf with a ^"1 Ver-- thickening 104a, 104b provided, which on the inner surface" and abuts the ring 103 105. The inner surfaces of the rings 103, 105 are each provided with a groove into which a sealing ring 111 or 112 is inserted. The chamber wall is between the two thickenings 104a, 104b

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provided with a helical groove which, together with the jacket 106, forms the helical channel 108. In this exemplary embodiment, the chamber wall 10 ¹ J and the partition wall 104c forming the side surfaces of the channel consist of a single workpiece. The outside diameter of the partition wall 104c is dimensioned such that the jacket can just be pushed over it. The jacket 106 is provided with an input connection 109 at one end of the channel 108 and with an output connection 110 at the other end.

At the end of the on the left in FIG In the grinding chamber 102 there is a ring 113 which is screwed to the ring 103 by means of screws 114. At the At the other end of the grinding chamber 102 there is a hinge 115 which is connected to the ring 105 by means of screws 116 is screwed. The rings 113,115 protrude to the inner edge of the. Chamber wall 104, lie on their annular End faces and are each sealed by a sealing ring or 118. The chamber wall 104 and the jacket 106 are thus detachably and tightly connected to one another.

The grinding chamber 102 is releasably attached to a flange 101b of the frame 101 at the left end. On the right At the end it is closed by a releasably attached flange 112. The gap separator and the rest Parts of the agitator ball mill are designed similarly to the embodiment shown in FIG.

In FIG. 4, a section from a further grinding chamber designated 202 can be seen. These has a cylindrical chamber wall 204 and a jacket 206. The latter is on the inside

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provided with a groove which, together with the chamber wall 204, forms the helical channel 208. the The partition wall 206a, which laterally delimits the channel 208, and the jacket 206 consist of one in this variant one-piece workpiece. The chamber wall 204 and the jacket 206 are otherwise similar to that in FIG Figure 3 illustrated embodiment releasably connected to one another.

When the ball mills are in operation, the chamber walls are worn out by the balls and must after a certain amount of time Operating time to be replaced. In the embodiments shown in Figures 3 and 4 is it is now possible to only replace the chamber wall and to continue to use the jacket. In the Figures 3 and 4 illustrated embodiments must, however, the chamber walls and the jacket with fairly be made with great accuracy so that the jacket can be pushed over the chamber walls and thus the partition walls 104c, 206a are still sufficient Leak tightness, so actually at least about half of the fluid along the canal flows. In the embodiment shown in Figures 1 and 2, the requirements are the manufacturing accuracy, however, is less great. The embodiment shown in Figures 1 and 2 is therefore expediently provided for grinding chambers with a large diameter. Smaller grinding chambers can, however, be produced according to the variants shown in FIGS. 3 and 4.

The slope of the helical channel can be about 6 to 10 % of the inner diameter of the grinding chamber. The width of the channel can be about 70 to 90 % of the slope and the height about 20xfcis 50 % of the slope,

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In certain applications it may be necessary to heat the grinding chamber. In this case it is natural It is easily possible, instead of a cold fluid, to flow a hot fluid through the channel allow. In addition, the fluid can be both liquid and gaseous.

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Claims (4)

PATENT CLAIMS jlJ agitator ball mill with a grinding chamber, with a cylindrical chamber wall and one that runs helically along the outer surface of the chamber wall Channel for a fluid used for cooling or heating, the interior of the Boundary surface of the channel facing the grinding chamber is formed by the outer surface of the chamber wall, characterized in that the interior of the Milling chamber (2,102,202) facing away from the boundary surface of the channel (8,108,208) through a to the chamber wall (4,104,204) coaxial jacket (6,106,206) is formed and that the two lateral boundaries of the Channel (8,108,208) through the two side surfaces of two successive helical turns a single partition wall (7> 104c, 206a) are formed. 2. agitator ball mill according to claim 1, characterized in that the chamber wall (4) on the outside is provided with a helical groove (4b) into which a separating wall (7) is formed Tape is inserted, and that the jacket (6) rests on the outer edge of the tape. 3. agitator ball mill according to claim 1, characterized in that that the chamber wall (104) and the partition wall (104c) consist of a one-piece workpiece and that the jacket (106) and the chamber wall (104) are detachably connected to one another. 4. agitator ball mill according to claim 1, characterized in that that the jacket (206) and the partition wall (206a) consist of a one-piece workpiece and ORIGINAL SHSPECTED 709886/0129 that the jacket (206) and the chamber wall (204) are detachable are connected to each other. The patent attorney Y \ n ι!. ^ ¹ I. 709886/0129