阅读说明：本技术 搅拌磨 (Stirring mill ) 是由 E·纳特 A·里切尔 N·克恩 A·斯特姆 于 2019-03-05 设计创作，主要内容包括：本发明提供一种用于加工可流动的研磨物料的搅拌磨。搅拌磨具有研磨容器(2)、由容器壁(9)界定的研磨室(8)、具有可绕中心纵轴线(19)旋转的并具有内径为d351的转子(35)的搅拌器。多个工具(38)安装在转子上并朝向容器壁延伸。搅拌磨还具有安置在转子之内的内定子(22)。在所述转子和内定子的外壁(23)之间形成研磨物料排出通道(47),研磨物料经此被输送至分离装置(30)且随后被送至排出管路。该研磨室至少部分填充有直径为c的研磨介质。在内定子的上方设置有具有直径d30的分离装置。对于转子和研磨介质分离装置之间的距离s适用的是：s＝0.5·(d351-d30)≤5·c。(The invention provides a stirring mill for processing flowable grinding materials. The agitator mill has a grinding vessel (2), a grinding chamber (8) delimited by a vessel wall (9), an agitator having a rotor (35) which is rotatable about a central longitudinal axis (19) and has an inner diameter d 351. A plurality of tools (38) are mounted on the rotor and extend toward the vessel wall. The agitator mill also has an inner stator (22) disposed within the rotor. Between the rotor and the outer wall (23) of the inner stator a grinding stock discharge channel (47) is formed, through which the grinding stock is conveyed to the separating device (30) and subsequently to the discharge line. The grinding chamber is at least partially filled with grinding media having a diameter c. Above the inner stator a separating device with a diameter d30 is arranged. What applies to the distance s between the rotor and the grinding medium separating device is: s is not more than 0.5 (d351-d30) and not more than 5.c.)

1. A stirring mill for processing flowable grinding material,

-having a grinding vessel (2) and a grinding chamber (8) delimited by a vessel wall (9),

-a stirrer having a rotor (35) rotatable about a central longitudinal axis (19) and having a diameter d351,

-wherein a plurality of tools (38) are mounted on the rotor (35) and extend towards the vessel wall (9),

-having an inner stator (22) arranged within the rotor (35),

-wherein a grinding material discharge channel is formed between the rotor (35) and the outer wall (23) of the inner stator (22),

-wherein the grinding chamber (8) is at least partially filled with grinding media having a diameter c, and

-wherein above the inner stator (22) a grinding media separation device (30) with a diameter d30 is arranged,

characterized in that the relationship applicable to the distance s between the rotor (35) and the grinding media separation device (30) is: s is not more than 0.5 (d351-d30) and not more than 5.c.

2. The agitator mill according to claim 1, characterized in that the relationship applicable to the distance s between the rotor (35) and the grinding medium separating means (30) is: s is not more than 0.5 (d351-d30) and not more than 3.c.

3. The agitator mill according to claim 1 or 2, characterized in that s is 2mm or less.

4. The agitator mill of claims 1 to 3, characterized in that the grinding medium separation device (30) has a cylindrical protective screen.

5. The agitator mill as claimed in claims 1 to 4, characterized in that the tool (38) mounted on the rotor (35) leaves only a small gap from the vessel wall (9), wherein the gap between the tool (38) and the vessel wall (9) has a gap width b for which, in terms of the diameter c of the grinding media, the applicable relationship is: b is not less than 4c and not more than 6c, wherein the minimum gap width b is not less than 1.0 mm and not more than 2.0 mm.

6. The agitator mill as claimed in any of claims 1 to 5, characterized in that a scraper means extending towards the rotor (35) is provided on the inner stator (22).

7. The agitator mill as claimed in claim 6, characterized in that the scraper means arranged on the inner stator (22) overlap one another in the direction of the central longitudinal axis (19) and are arranged on the inner stator (22) in such a way that they exert an impulse directed in the flow direction on the grinding media when the rotor (35) is driven.

8. The mixer mill according to claim 7, characterized in that a gap is formed between the scraping means and the rotor (35), for which gap width e the relation applies in respect of the diameter c of the grinding media of 4c ≦ e ≦ 6c, wherein for the minimum gap width e: c is more than or equal to 1.0 mm and less than or equal to 2.0 mm.

9. The mixer mill according to any of the claims 1 to 8, characterized in that a second tool (74) is arranged on the vessel wall (22), which second tool extends towards the rotor (35).

10. The agitator mill as claimed in any of claims 1 to 9, characterized in that a grinding-medium return channel (55) for returning the grinding medium (43) from the region of the grinding-medium separating device (30) to the grinding chamber (8) is formed in the agitator (20).

11. The agitator mill of any of claims 1 to 10, wherein, in terms of the diameter c of the grinding media, it applies that: c is less than or equal to 0.65 mm, preferably less than or equal to 0.02 mm and less than or equal to 0.3 mm.

Technical Field

The present invention relates to a mixer mill according to the preamble of claim 1.

Background

The present invention is described in EP1992412A 1. Such a stirring mill is known from this document. A stirred mill is used to disperse solids in suspension, i.e. liquid. It can be used, for example, in the manufacture of adhesives, printing inks, cosmetics and pharmaceuticals. For this purpose, the grinding material is fed through a feed channel into a grinding chamber of the agitator mill, which is formed between the outer wall of the rotor and the vessel wall, and is comminuted together with auxiliary grinding media, also referred to below as grinding media, such as ceramic balls, by means of tools arranged on the rotor and/or the vessel wall. The agglomerates are dispersed by the stirring motion and the crystal structure is broken up. Here, the initial particle size may be reduced from 100-500 microns to less than 3 microns. The finished product is then guided through the grinding stock discharge channel to the discharge line via a grinding medium separation device, in particular in the form of a protective screen. In this case, the rotor forms a kind of cage rotating around the separating device.

In such a stirred mill, the grinding media should be located as far as possible only in the grinding chamber between the rotor and the vessel wall. The grinding media are accelerated and concentrated outwardly by means of tools mounted on the rotor and extending to the vicinity of the vessel wall and by the centrifugal forces generated. If the tool is arranged on the vessel wall, the tool extends towards the rotor. The tools, which may be arranged on the vessel wall, are preferably arranged offset to the tools mounted on the rotor, so that the tools can pass between the tools arranged on the vessel wall when the rotor rotates. The grinding material flows through the dense packing of grinding media toward the rotor axis. By concentrating the grinding media in the grinding chamber, their entry into the ground material discharge channel can be substantially avoided. In addition to the concentration of grinding media in the annular outer grinding chamber, means designed to prevent grinding media from flowing to the separating device are also provided in the mill stock discharge channel.

In the grinding stock discharge channel, which is usually arranged within the rotor and is delimited by the rotor and the inner stator, there is therefore as little or no grinding media as possible. However, the pressure in the agitator mill increases as a result of the grinding media accumulating at the separating device, which can lead to a reduction in product and even to an automatic shut-down in order to avoid damage to the agitator mill. In a stirred mill according to the prior art, a scraper may be mounted on the separating device, which scraper moves the grinding media away from the separating device. However, this may be undesirable when dispersing heat sensitive materials, particularly explosives or other hazardous materials, as the scrapers may cause heat generation in the ground material.

Disclosure of Invention

The object of the invention is to avoid the sedimentation of grinding media at the grinding media separation device and the consequent clogging of the separation device caused by the traction force.

According to the invention, this object is achieved by the features of claim 1. The core of the invention is that the accumulation of grinding media at the separating device is effectively prevented by reducing the distance between the rotor and the separating device. This can be achieved by increasing the diameter of the separating apparatus, i.e. in particular the screen diameter. In particular, the distance between the rotor and the separating device can be selected as a function of the diameter of the grinding media, and not merely as a function of the structural dimensions of the agitator mill. Furthermore, a maximum value independent of the size of the grinding media can be set for this distance. These measures can reduce the build-up of grinding media that are deposited at the separation device by the drag force. Thus, not only a stable product flow but also a rapid breaking of coarse particles in the product to be dispersed will be ensured.

In particular, this object is achieved by a stirring mill having the following features. The agitator mill has a grinding vessel and a grinding chamber delimited by a vessel wall and an agitator rotatable about a central longitudinal axis and having a rotor with an inner diameter d 351. A plurality of tools are mounted on the rotor and extend toward the vessel wall. Furthermore, a second tool extending towards the rotor may be arranged on the vessel wall. The agitator mill also has an inner stator disposed within the rotor. Between the rotor and the outer wall of the inner stator there is formed a grinding stock discharge channel, through which the grinding stock is led to a separating device and subsequently to a discharge line. The grinding chamber is at least partially filled with grinding media having a diameter c. Above the inner stator a separating device with a diameter d30 is arranged. The distance s between the rotor and the separating device is determined by the difference between the inner diameter of the rotor and the diameter of the separating device. According to the invention, this distance s is selected according to the grinding medium diameter c and is 0.5- (d351-d 30). ltoreq.5 c. In another preferred embodiment, the distance s can be s.ltoreq.3 · c in relation to the grinding medium diameter c. Furthermore, according to an embodiment of the invention, the value of the distance s should also not exceed 2mm, independent of the size of the grinding media.

Preferably, the tool mounted on the rotor can leave only a small gap from the vessel wall 9, wherein the gap has a gap width b for which the applicable relation is, in terms of the diameter c of the grinding media: 4 c. ltoreq. b.ltoreq.6 c, where 1.0 mm. ltoreq. b.ltoreq.2.0 mm is suitable as the minimum gap width b.

A scraping tool extending towards the rotor may be arranged on the inner stator. The scraper tools, if any, preferably overlap one another in the direction of the central longitudinal axis and are arranged on the inner stator in such a way that they exert an impulse directed in the direction of flow on the grinding medium when the rotor is driven.

Preferably, a gap is formed between the scraper tool and the rotor, for which gap width e, in terms of grinding medium diameter c, the applicable relation is: 4c < e < 6c, where 1.0 mm < c < 2.0 mm applies for the minimum gap width e.

In addition, in the agitator, the grinding medium return channel is designed to return grinding medium from the region of the separating device to the grinding chamber.

With respect to the diameter c of the grinding media, a suitable relationship is c.ltoreq.0.65 mm, preferably 0.02 mm. ltoreq.c.ltoreq.0.3 mm.

Drawings

Other features, advantages and details appear from the following description of the invention taken in conjunction with the accompanying drawings in which:

fig. 1 shows a detail of a stirring mill according to an embodiment of the invention in a vertical longitudinal section.

Detailed Description

The agitator mill shown in fig. 1 generally has a milling container 2 with an internal milling chamber 8. The grinding chamber 8 is at least partially filled with grinding media 43 (not shown) having a diameter c. The agitator mill also has an inner stator 22 and a rotor 35 which is rotatable about the central longitudinal axis 19 and has a diameter d 351. In this case, a grinding material discharge passage 47 is formed between the outer wall 23 of the stator 22 and the rotor 35. A tool 38 is mounted on the rotor 35 and projects into the grinding chamber 8. Furthermore, the second tool 74 is arranged on the vessel wall 9 offset from the tool mounted on the rotor 35. Above the stator 22 is located a protective screen 30 as a separating device, which is designed to be rotationally symmetrical about the central longitudinal axis 19. The protective screen 30 prevents the grinding media 43 from flowing into the downstream discharge line 31 within the inner stator 22. A distance s is formed between the protection screen 30 and the rotor 35. The distance s can be described here as the relationship s 0.5 (d351-d30) and can be set in particular by selecting the diameter d30 of the protective screen 30.

As the size of the agitator mill increases, the distance s that was originally between the screen 30 and the rotor 35 is also selected to be correspondingly greater. But contrary to expectations this does not lead to a proportional increase of the product flow. In contrast, the product flow is always unexpected.

This is related to the fact that, in operation, it may occur: despite the mechanism for intercepting the grinding media 43, they may still be deposited at the protective screen 30 due to traction forces. This can result in reduced flow or complete screen plugging.

To effectively prevent this, the distance s between the protection screen 30 and the rotor 35 is reduced. The distance s can be selected in dependence on the grinding medium diameter c and independently of the configuration of the agitator mill. This results in a higher permeability of the agitator mill, since the risk of the grinding media 43 depositing at the protective screen 30 is reduced, resulting in a faster breaking up of coarse particles in the product to be dispersed.

According to the invention, the distance s between the protective screen 30 and the rotor 35 is, in relation to the grinding medium diameter c, s.ltoreq.5 c or 0.5 ≦ 5 c (d351-d 30).

In another preferred embodiment, in relation to the grinding medium diameter c, for the distance s between the protective screen 30 and the rotor 35, the following applies: s is less than or equal to 3 · c.

In another preferred embodiment, the distance s is no greater than 2mm, also independent of the size of the grinding media.

Although the above described embodiment shows a blender mill having a vertical central longitudinal axis 19, the description may be immediately applicable to a horizontal attitude or an attitude therebetween.