Agitator and agitating hook provided therein

Provided are an agitator and an agitating hook provided therein. The agitator includes a rotary shaft rotatably installed in a reactor, rotor blades installed at an outer circumference of the rotary shaft and rotated with the rotary shaft to agitate a material therein, and an agitating hook constituted by a pair of members spaced apart from each other at an inner wall of the reactor and through which the rotor blades pass. Here, a gap between the agitating hook is larger at an outlet port through which the rotor blade leaves than at an inlet port through which the rotor blade enters. Since a pressure is uniformly applied from the inlet port through which the rotor blade enters to the outlet port through which the rotor blade leaves, a torsional moment applied to the agitating hook is minimized. Therefore, it is possible to improve durability of the agitating hook and increase reliability of products.

This application is a National Stage Entry of International Application No. PCT/KR2010/007536, filed Oct. 29, 2010, and claims the benefit of Korean Application No. 10-2009-0103833, filed on Oct. 29, 2009, which are hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

1. Field of the Invention

The present invention relates to an agitator, and more particularly, to an agitator capable of improving durability of an agitating hook for agitating a high viscosity material with rotor blades, and an agitating hook provided therein.

2. Discussion of Related Art

In general, polymerization refers to a reaction in which small molecules are repeatedly added to form a single long continuous chain. Here, a small unit molecule is referred to as a unit body. An agitator is needed in a polymerization reactor, which performs polymerization, to agitate a high viscosity fluid or gel-type material having a viscosity higher than a predetermined level.

FIG. 1is a perspective view showing a configuration of a conventional agitator, andFIG. 2is an enlarged perspective view of a portion of the agitator shown inFIG. 1.

As shown in the drawings, the agitator has a substantially cylindrical shape, in which an agitation member is installed. The agitator shown inFIG. 1may be installed in plural in the cylinder to perform agitation. A rotary shaft3is rotatably installed at a center in an inner space defined by an inner wall1of the agitator. The rotary shaft3receives power from a power source such as a motor to be rotated.

A plurality of rotor blades5are installed at an outer circumference of the rotary shaft3. The plurality of rotor blades5may be installed at the outer circumference of the rotary shaft3at a predetermined interval. The rotary blades5may be rotated together with the rotary shaft3to substantially agitate a high viscosity material. The rotary blade5has a substantially fan-shape.

In addition, agitating ribs7are formed at ends of the rotary blades5, respectively. The agitating ribs7perpendicularly project from the ends of the rotor blades5. Referring toFIG. 3, the agitating rib7perpendicularly extends from the end of the rotor blade5in both directions. Meanwhile, the agitating rib7passes through a rib passing part13, which will be described.

An agitating hook10is installed at the inner wall1to agitate and crush a high viscosity material. The agitating hook10may be provided around the inner wall1in plural. As shown inFIG. 2, the agitating hook10is formed of a pair of symmetrical members spaced apart a predetermined distance from each other. In addition, the rotor blade5and the agitating rib7pass through the agitating hook10to agitate and crush the high viscosity material.

Referring toFIG. 2, the agitating hook10includes support parts12projecting from the inner wall1of the reactor and spaced apart a predetermined gap from each other, connecting parts14extending from tips of the support parts12in facing directions, and parallel parts16parallelly extending from tips of the connection parts14.

In addition, the rib passing part13through which the agitating rib7passes is formed between the support parts12, and a blade passing part17through which the rotor blade5passes is formed between the parallel parts16. The rib passing part13has a relatively larger width than that of the blade passing part17, because a width of the agitating rib7is larger than that of the rotor blade5.

In order to prevent interference between the agitating hook10and the rotor blade5during rotation, a predetermined gap must be formed therebetween. This is also similar to the agitating rib7. This is shown inFIG. 3well. That is, the high viscosity material passes through the gap formed between the agitating hook10and the rotary blade5to be crushed.

Specifically describing the agitation and crush operation of the agitating hook10, first, a high viscosity fluid or gel-type material is inserted into the agitator. In general, a high viscosity material agitated in the agitator has a viscosity of 10,000 cp or more. Such a material is likely to be changed from a liquid phase into a solid phase so that the volume thereof is abruptly expanded.

When the high viscosity material is input, the material is conveyed from an inlet port to an outlet port and sequentially converted from the liquid phase into a gel type and from the gel type into a solid phase. In particular, as described above, the volume is abruptly expanded while the gel-type is converted into the solid phase. The solid lumps pass through the agitating hooks10to be agitated and crushed by rotation of the rotor blades5.

However, the conventional art as described above has the following problems.

As shown inFIGS. 3 and 4, the agitating hook10through which the rotor blade5passes has a constant gap from an inlet port through which the rotor blade5enters and an outlet port through which the rotor blade5leaves. Since the gap between the rotor blade5and the agitating hook10is constant, a pressure applied to the agitating hook10is increased from the inlet port to the outlet port as shown inFIG. 4.

When the pressure applied to the agitating hook10is not constant and increased as it goes toward the outlet port, a torsional moment is applied to the agitating hook10due to a difference in pressure. That is, the agitating hook10receives a force to be rotated in an arrow direction shown inFIG. 5.

Since such a moment is repeatedly applied to the agitating hook10whenever the rotor blades5continuously pass through the agitating hook10, the agitating hook10may be failed due to fatigue. In particular, when the moment is continuously applied to the support parts12of the agitating hook10, the agitating hook10may be broken to be separated from the inner wall1.

Eventually, when the agitating hook10is broken, since the agitator cannot be normally operated, agitation efficiency is decreased and repair cost is increased.

SUMMARY OF THE INVENTION

In order to solve the problems, the present invention is directed to an agitator having a structure capable of minimizing a torsional moment applied to an agitating hook, and an agitating hook provided therein.

In example embodiments, an agitator includes: a rotary shaft rotatably installed in a reactor; rotor blades installed at an outer circumference of the rotary shaft and rotated with the rotary shaft to agitate a material therein; and an agitating hook spaced apart from each other at an inner wall of the reactor and through which the rotor blades pass. Here, a gap between the agitating hook is larger at an outlet port through which the rotor blade leaves than at an inlet port through which the rotor blade enters.

The gap between the agitating hook may be increased from the inlet port through which the rotor blade enters to the outlet port.

Inclined surfaces may be formed at facing surfaces of the agitating hook so that the gap is increased from the inlet port through which the rotor blade enters to the outlet port.

The rotor blade may further include an agitating rib perpendicularly extending from an end of the rotor blade.

A blade passing part through which the rotor blade passes and a rib passing part through which the agitating rib passes may be formed between the agitating hook, and the blade passing part may have a width smaller than that of the rib passing part.

The agitating hook may include: support parts projecting form the inner wall of the reactor at a predetermined interval and between which the rib passing part is formed; connection parts extending from tips of the support parts in facing directions; and parallel parts parallelly extending from tips of the connection parts and between which the blade passing part is formed.

Inclined surfaces may be formed at facing surfaces of the parallel parts so that the gap is increased from the inlet port through which the rotor enters and the outlet port.

The parallel parts may further include extension parts perpendicularly extending from tips of the parallel parts in opposite directions.

The outlet port may have a width 1.0 to 2.0 times larger than that of the inlet port.

The outlet port may have a width 1.3 to 1.5 times larger than that of the inlet port.

The agitating hook may be formed of a stainless steel material.

An agitating hook includes: support parts projecting from an inner wall of a reactor at a predetermined interval; connecting parts extending from tips of the support parts in facing directions; and parallel parts parallelly extending from tips of the connecting parts to have a width smaller than that of the support parts.

A rotor installed at a reactor may pass between the support parts, and an outlet port through which the rotor blade leaves may have a width 1.0 to 2.0 times larger than that of an inlet port through which the rotor blade enters.

The outlet port may have a width 1.3 to 1.5 times larger than that of the inlet port.

Inclined surfaces may be formed at facing surfaces of the agitating hook so that the width is increased from the inlet port through which the rotor blade enters to the outlet port.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Hereinafter, example embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms. The following embodiments are described in order to enable those of ordinary skill in the art to embody and practice the present invention.

Hereinafter, an exemplary embodiment of an agitator and an agitating hook provided therein in accordance with the present invention will be described in detail with reference to the accompanying drawings. In addition, like elements of the present invention are designated by like reference numerals of the conventional art shown inFIGS. 1 to 5.

FIG. 6is a perspective view showing an agitating hook and a rotor blade in accordance with an exemplary embodiment of the present invention, andFIG. 7is a perspective view showing the agitating hook in accordance with the present invention.

As shown, an agitating hook20in accordance with the present invention includes support parts22projecting from an inner wall1of a reactor at a predetermined interval and defining a rib passing part23formed therebetween, connection parts24extending from tips of the support parts22in facing directions, and parallel parts26parallelly extending from tips of the connection parts24and defining a blade passing part27formed therebetween.

In this embodiment, inclined surfaces28are formed at facing surfaces of the parallel parts26. The inclined surfaces28is formed to minimize a torsional moment applied to the agitating hook20, and uniformly distribute a pressure applied to facing surfaces of the parallel parts26.

In other words, during a process of passing the rotor blade5between the parallel parts26, an inlet port through which the rotor blade5has a smaller width than an outlet port through which the rotor blade5leaves to offset the pressure strongly applied to the outlet port (seeFIG. 4). The inclined surfaces28are configured such that a gap therebetween is increased from the inlet port to the outlet port through which the rotor blade5passes, i.e., increased along the straight surface. In addition, the blade passing part27between the parallel parts26also has a width which is increased from the inlet port to the outlet port through which the rotor blade5passes.

Meanwhile, the inclined surfaces28must not be the straight surfaces as described above but may have only the width larger at the outlet port than at the inlet port through which the rotor blade5passes.

For this,FIGS. 8 and 9show other embodiments of the agitating hook in accordance with the present invention. Referring toFIGS. 8 and 9, inclined surfaces28′ and28″ formed at facing surfaces of the parallel parts26may have curved shapes as shown inFIGS. 8 and 9such that the width is increased from the inlet port to the outlet port in concave or convex shapes. Of course, the inclined surfaces28may be designed to have different shapes, in addition to the embodiments shown in the drawings.

For reference,FIG. 10shows an actual design of the agitating hook in accordance with the present invention. Here, detailed description of the constitution corresponding toFIG. 6will not be repeated.

Referring toFIG. 10, the entire shape of the agitating hook120is similar to that ofFIG. 6. Reviewing the different parts, unlikeFIG. 6, connection parts124of the agitating hook120extends in an inclined direction at a predetermined angle with respect to the support parts122, not perpendicular with respect to the support part122. In addition, extension parts130further extend from tips of the parallel parts126in opposite directions. Of course,FIG. 10merely shows an example of the actual design, but not limited thereto.

In addition, in the agitating hook20in accordance with the present invention, the outlet port through which the rotor blade5leaves has a width 1.0 to 2.0 times larger than that of the inlet port. In addition, the outlet port through which the rotor blade5leaves may have a width 1.3 to 1.5 times larger than that of the inlet port. This is because the high viscosity material can be more effectively agitated and crushed and the torsional moment applied to the agitating hook20can be minimized under the condition that the inlet port and the outlet port have the widths of the above proportion.

Meanwhile, the agitating hook20in accordance with the present invention may be formed of the following material. The agitating hook20may be formed of stainless steel (for example, SUS). The stainless steel is a steel member having good corrosion-proof, machinability and weldability. In this embodiment, duplex having good strength and corrosion-proof, among the stainless steel, is used. The duplex is a material that is widely used in a field such as a marine power plant in which corrosion due to salt may occur.

Next,FIGS. 11 and 12shows graphs for comparing stress distributions and strain distributions of the agitating hook in accordance with the present invention and the conventional agitating hook. For reference, (a) shows the conventional agitating hook, and (b) shows the agitating hook in accordance with the present invention.

Referring to the figures, inFIG. 11, (a) shows that both ends of the support parts22have very high stresses, and (b) shows that only one end adjacent to the outlet port has a high stress. In addition, it will be appreciated that the entire stress is represented as low in (b).

Further, inFIG. 12, it can be seen that strain generated at an outer side of the support parts22is remarkably reduced at (b) than at (a). In addition, it will be appreciated that strain generated from the inclined surfaces28of the parallel parts26is reduced at (b) than at (a).

Actually, through analysis ofFIGS. 11 and 12, it will be appreciated that the stress of the agitating hook in accordance with the present invention is reduced to 70% and the strain is also reduced to 10% in comparison with the conventional agitating hook.

As can be seen from the foregoing, an agitating hook of the present invention through which a rotor blade passes includes an outlet port having a width larger than that of the inlet port. Since the pressure is uniformly applied from the inlet port of the agitating hook through which the rotor blade enters to the outlet port through which the rotor blade leaves, a torsional moment applied to the agitating hook can be minimized. Therefore, it is possible to improve durability of the agitating hook and increase reliability of products.