KR20020069865A - Milling machine - Google Patents

Abstract

PURPOSE: A size reduction machine is provided which not only maintains injection amount of raw materials constantly through an impeller position adjusting member, but also improves uniformity of powder of the raw materials by properly adjusting a gap between screen and impeller. CONSTITUTION: The size reduction machine(100) comprises a frame(105) equipped with a supporting plate(110) and a plurality of supporting legs(141-144); a control panel(120) installed at one side of the upper part of the supporting plate(110); a hopper(125) mounted on the upper part of the other side of the supporting plate(110); a main panel(115) installed at the lower part of one side of the supporting plate(110); an impeller housing(135) which is installed at the lower part of the other side of the supporting plate(110), and on the inner part of which screen and impeller are mounted; and a driving unit which is installed between the main panel(115) and the impeller housing(135) and between the control panel(120) and the hopper(125), wherein first to fourth supporting legs(141-144) are installed at four corners of the lower part of the supporting plate(110), first to fourth moving members(171-174) are mounted on the lower part of the first to fourth supporting legs(141-144) respectively, the main panel(115) is installed between the first and second supporting legs(141,142) at the lower part of one side of the supporting plate(110), one or more fixed rods(151,152) are installed between the third and fourth supporting legs(143,144) at the lower part of the other side of the supporting plate(110), the driving unit comprises a driving motor part(130), a first pulley, a second pulley, a belt and a cover(155), and the size reduction machine(100) further comprises a supporting rod(180) which is installed at the upper part of one side of the supporting plate(110) to support the control panel(120) and equipped with a length adjusting means to adjust height of the control panel(120).

Description

Milling machine

The present invention relates to a pulverizer, and more particularly, a raw material that can be uniformly pulverized with an impeller position adjusting member and an improved screen, etc., which can arbitrarily adjust the gap between the screen and the impeller. The present invention relates to a pulverizer that can greatly improve the crushing efficiency.

In general, a size reduction machine refers to a device used in the pharmaceutical field or the cosmetic manufacturing field to establish a dried raw material or establish a poor tablet to obtain a fine powder. Therefore, the pulverizer used in cosmetic manufacturing or pharmaceutical processes should be able to crush raw materials or tablets into powder having a uniform size. Conventionally, a pulverizer used in food, pharmaceutical or cosmetics manufactures an impeller in a screen or sieve in which holes having a predetermined diameter are formed, and the impeller rotates by inserting raw materials to be crushed between the screen and the impeller. As a result, the principle of pulverizing the raw material by the rotational force of the impeller and the friction force generated between the screen and the impeller is used.

Such mills are disclosed in US Pat. No. 4,759,507 to Daniel N. Lynch et al. And US Pat. No. 5,330,113 to Kimberly J. Poser et al.

Figure 1 shows a cross-sectional view of the mill disclosed in the US Patent No. 5,330,113.

Referring to FIG. 1, the grinder includes a cabinet-shaped body housing 10, a cylindrical impeller housing 15, a support tube 20 connecting the impeller housing 15 to the body housing 10, and an impeller. A screen 25 mounted in the housing 15 and an impeller 30 fastened to the screen 25.

The body housing 10 is installed on a base plate 40 disposed below the body housing 10, and the electric motor 45, the shaft connecting portion 50 and the bend from below are inside the body housing 10. The gear box 55 is installed. The shaft of the electric motor 45 is connected to the drive shaft 65 located in the support tube 20 via the shaft connection 50 and the bending gear box 55.

The bending gear box 55 transfers the rotational force of the vertically arranged electric motor 45 in the horizontal direction and transmits it to the drive shaft 65. The shaft connecting portion 50 is installed in the connecting housing 60 located on the electric motor 45, the bending gear box 55 is installed on the connecting housing 60.

One side of the drive shaft 65 is connected to the bending gear box 55 through the connecting member 70, the other side is connected to the gear box 75 installed inside the impeller housing 15. The gear box 75 converts the rotational force of the drive shaft 65 in the vertical direction again to rotate the impeller 30 installed thereon.

The screen 25 has a conical shape with an end cut, and a plurality of holes are formed on the side of the screen 25. The raw material introduced between the screen 25 and the impeller 30 is crushed to a predetermined size by the friction force between the impeller 30 and the screen 25 as the impeller 30 rotates in the screen 25. It passes through the holes of the screen 25 and then exits to the outlet 80.

However, in the above-described conventional grinder, there is a disadvantage that it is difficult to adjust the distance between the impeller and the screen because the position of the impeller cannot be adjusted while the impeller rotates in the screen to crush the raw material. That is, since the impeller is initially mounted to be set at a predetermined interval between the impeller and the screen, the gap between the screen and the impeller cannot be adjusted even if the amount of the raw material injected and crushed is changed.

As a result, when the amount of the raw material is large, the size of the raw material powder discharged through the screen is too large because the impeller forcibly pushes the raw material, and when the amount of the raw material is small, the grinding of the raw material smoothly between the screen and the impeller. The problem is that it is not performed, and as a result, the uniformity of the raw material powder discharged through the grinder is greatly reduced.

In addition, the conventional pulverizer is equipped with a screen having a hole having a constant diameter regardless of the type of raw materials to be put in, and since the size of the holes formed in the screen is generally very small, the area occupied by the holes is smaller than the total screen area. There is a problem that the efficiency of the crusher equipped with a lowering.

In addition, the conventional screen forms a plurality of holes in a metal plate having a smooth surface, and then uses them by winding them in a conical shape, so that the particle size of the raw material powder is uniform when the input raw material is a relatively hard material. Not only is it difficult to control, but the efficiency of the crusher to grind the raw material has a disadvantage in that the long time to grind in order to make the raw material powder has a predetermined diameter.

Therefore, an object of the present invention is to maintain the input amount of the raw material through the impeller position adjusting member and at the same time to properly adjust the distance between the screen and the impeller during the operation of the grinder according to the input amount of the raw material uniformity of the powder It is to provide a grinder that can be improved.

Another object of the present invention is to provide a grinder capable of maintaining the uniformity of the powder and improving the efficiency of the grinder according to the type of raw material and the amount of the raw material having a screen having an improved structure.

1 is a cross-sectional view of a conventional grinder.

2 is a perspective view of a grinder according to the present invention.

3 is a front partial projection view of the apparatus shown in FIG. 3.

4 is a side view of the apparatus shown in FIG. 2.

FIG. 5 is an enlarged cross-sectional view of the apparatus shown in FIG. 2 centered on an impeller housing. FIG.

6A and 6B are cross-sectional views illustrating the operation of the impeller position adjusting member according to the present invention.

FIG. 7 is a plan view of the positioning rod of the apparatus shown in FIGS. 6A and 6B.

8A and 8B are perspective and cross-sectional views, respectively, of a conventional screen.

9A and 9B are respectively perspective and cross-sectional views of the screen according to the invention.

<Explanation of symbols for main parts of drawing>

100: crusher 105: frame

110: support plate 115: main panel

120: control panel 125: hopper

130: drive motor unit 133: electric motor

135: impeller housing

141, 142, 143 and 144: first to fourth supporting legs

151 and 152: first and second fixed rods 155: cover

160: Guide member

171, 172, 173, and 174: first to fourth moving members

180: support rod 185: length adjustment member

191, 192: First and second pulleys 195: Belt

200 ： Impeller 210 ： Screen

220: spindle assembly 225: spacer collar

230: impeller screw 240: drive shaft

250: impeller position adjustment member 255: fixation stand

260: Positioning rod 265: Impeller moving member

280 ： Sloped hole 290 ： Flange

295 ： support

According to the present invention for achieving the above object of the present invention, a frame having a support plate and a plurality of support legs, a control panel installed on one side of the support plate, a hopper mounted on the other side of the support plate, the A main panel installed on one side lower portion of the support plate, an impeller housing mounted on the other lower portion of the support plate, and having a screen and an impeller mounted therein, and a drive installed between the main panel, the impeller housing, the control panel, and the hopper; There is provided a grinder comprising a unit.

First to fourth support legs are installed at the lower four corners of the support plate, and first to fourth moving members are mounted to the lower portions of the first to fourth support legs, respectively. In this case, the main panel is installed between the first and second support legs of the lower portion of the support plate, and at least one fixing rod is installed between the third and fourth support legs of the lower portion of the support plate.

Preferably, the drive unit includes a drive motor unit mounted between the main panel and the impeller housing, a first pulley installed on the support plate adjacent to the control panel, and a first motor mounted on the support plate adjacent to the hopper. 2 pulleys and a belt mounted between the first and second pulleys. In this case, an electric motor is installed in the driving motor unit, the shaft of the electric motor is connected to the first pulley, and the second pulley is connected to the impeller so that the electric power of the electric motor is driven by the first pulley, the belt and It is delivered to the impeller through the second pulley.

The drive unit may further include a cover that protects the first pulley, the second pulley and the belt.

The hopper and the impeller housing are connected to each other through a guide member, a support rod for supporting the control panel and having a length adjusting means is formed on one side of the support plate to adjust the height of the control panel.

Preferably, a spindle assembly is installed in the upper part of the impeller in the impeller housing, the drive shaft is coupled to the impeller in order to transmit the rotational force of the drive unit to the impeller. In this case, an impeller screw is formed at a lower end of the impeller located inside the screen, and a spacer collar is formed between the impeller and the spindle assembly.

In addition, an impeller positioning member for adjusting the gap between the impeller and the screen is provided, the impeller positioning member is a fixing rod formed on the other side of the support plate, one side is fastened to the fixing rod and the other side is the drive shaft Positioning rod is hinged to the support, the support for supporting the center portion of the positioning rod and the impeller moving member for moving the other side of the positioning rod fastened to the fixed in the vertical direction. At this time, the impeller moving member is a nut, a thread corresponding to the nut is formed on the outer peripheral surface of the fixing stand.

Preferably, the side of the screen is formed with a plurality of inclined holes inclined at an angle of about 40 to 50 degrees, the metal protrusions are formed in the periphery of the inclined holes toward the inside of the screen.

According to the present invention, it is possible to easily adjust the distance between the screen and the impeller during the operation of the grinder according to the type of raw material or the input amount of the raw material by mounting the impeller positioning member including a positioning rod, a fixed rod, an impeller moving member In addition, the uniformity of the raw material powder to be pulverized can be greatly improved, and the efficiency of the pulverizer can be increased. In addition, by adopting a screen having an improved structure provided with inclined holes and protrusions on the side, it is possible to effectively grind even when a solid raw material is introduced, as well as to increase the friction force generated between the screen and the impeller to significantly increase the grinding efficiency of the raw material. Can be improved.

Hereinafter, a detailed description will be given of a pulverizer according to a preferred embodiment of the present invention with reference to the accompanying drawings, but the present invention is not limited or limited by the following embodiments.

FIG. 2 shows a perspective view of a mill according to the invention, FIG. 3 is a front partial projection of the device shown in FIG. 3, and FIG. 4 is a side view of the device shown in FIG. 2.

2 and 3, the grinder 100 according to the present invention includes a frame 105, a main panel 15, a control panel 120, a hopper 125, a driving motor unit 130, and an impeller housing ( 135, a cover 155, and a guide member 160.

The frame 105 includes a support plate 110 installed flat with respect to a horizontal plane, and first to fourth support legs 141, 142, 143, and 144 mounted below the support plate 110. The first to fourth support legs 141, 142, 143, and 144 are vertically attached to the lower four corner portions of the support plate 110, respectively, and the first and second support legs of the lower side of one side of the support plate 110 ( The main panel 115 is positioned between 141 and 142.

In addition, the first and second fixing rods 151 and 152 are installed side by side in the horizontal direction between the third and fourth supporting legs 143 and 144 at the lower side of the other side of the supporting plate 110 to support the first and third supports. The legs 143 and 144 are prevented from being spaced apart by more than a predetermined interval. Therefore, it is possible to improve the operation and the movement stability of the grinder 100 during the operation of the present grinder 100 or while moving the grinder 100.

First to fourth moving members 171, 172, 173, and 174 are fixed to the lower portions of the first to fourth supporting legs 141, 142, 143, and 144 so as to easily move the grinder 100, respectively. do. Preferably, the first to fourth moving members (171, 172, 173, 174) is made of a wheel attached to the fixing device to move the present mill 100 and at the same time fixed to the desired place.

Referring to FIG. 4, the main panel 115 is mounted below one side of the support plate 110. In the main panel 115, electrical wiring and a circuit board (not shown) for the driving motor 130 and the control panel 120 are installed. One side of the main panel 115 is provided with a door that can open and close the inside and is accessible inside the main panel 115 through the door, thereby easily replacing or repairing the electrical wiring and the circuit board.

Referring to FIGS. 2 and 3 again, the control panel 120 is installed on one side of the support plate 110 via the support rod 180. That is, the support rod 180 is installed on the support plate 110, and a control unit in which a display unit, an indicator light, and a plurality of buttons are formed on the front side of the support rod 180 to control the operation of the grinder 100. The panel 120 is installed. The main panel 115 is positioned below the support plate 110 on which the control panel 120 is installed.

The support rod 180 is provided with a length adjusting member 185 that can adjust the length of the support rod 180 can change the length of the support rod 180, so that the support rod 180 according to the user or the use environment The height of the control panel 120 installed in the upper portion can be adjusted.

The other side of the support plate 1150 is installed with a funnel-shaped hopper 125 into which the raw material is injected, and the cover 155 is mounted on the support plate 110 between the hopper 125 and the support rod 180. The cover 155 is adjacent to the hopper 125 and spaced apart from the support rod 180 on which the control panel 120 is installed at a predetermined interval.

The driving motor unit 130 is installed at a position adjacent to the main panel 115 at the lower center of the support plate 110, and the impeller housing 135 has a hopper 125 at an upper portion of the lower portion of the support plate 110. It is formed adjacent to the part located. A guide member 160 inclined at a predetermined angle is provided between the hopper 125 and the impeller housing 135 to supply raw materials to be crushed from the hopper 125 to the impeller housing 135.

The drive motor 130 is provided with an electric motor 133 which can be controlled through the control panel 120, and the shaft of the electric motor 133 is located on the support plate 110 in the cover 155. 191). In addition, a second pulley 192 is installed at an upper portion of the impeller housing 135 in the cover 155, and an impeller 200 to be described later is connected to the second pulley 192. Belts 195 are connected to the first and second pulleys 191 and 192, respectively, to transmit rotational force transmitted from the shaft of the driving motor 133 to the impeller 200 so that the raw material is crushed. The drive motor 133, the first and second pulleys 191 and 192, and the belt 195 together constitute a driving unit.

FIG. 5 is an enlarged cross-sectional view of the apparatus shown in FIG. 2 centered on an impeller housing. FIG.

Referring to FIG. 5, in the impeller housing 135, a conical screen 210 having a flange formed at a periphery from a lower portion thereof and an end portion thereof cut off, and an impeller positioned at a predetermined interval within the screen 210 ( 200 and the spindle assembly 220 disposed above the impeller 200 are sequentially installed.

An impeller screw 230 is mounted on the bottom of the impeller 200 to prevent the lower part of the impeller 200 from directly contacting the screen 210 and to allow the impeller 200 to easily rotate within the screen 210. do. In addition, a spacer collar 225 is installed between the impeller 200 and the spindle assembly 220 to prevent the impeller 220 from entering the spindle assembly 220.

As shown in FIG. 5, when the raw material to be crushed is introduced into the hopper 125, the injected raw material is interposed between the screen 210 and the impeller 200 along the inclined guide member 160 installed under the hopper 125. Is committed. When the rotational force generated from the driving motor 133 is transmitted to the impeller 200 through the first pulley 191, the belt 195, the second pulley 192, and the spindle assembly 200, the impeller 200 is predetermined. It will rotate at the speed of.

Therefore, the raw material introduced between the screen 210 and the impeller 200 is pulverized by the rotational force of the impeller 200 and the friction force between the screen 210 and the impeller 200, and the pulverized raw material is formed in the screen 210. It is discharged through the holes of the discharge port formed in the lower portion of the impeller housing (135). In this case, in order to uniformly crush the raw material and improve the efficiency of the raw material crushing, it is necessary to appropriately adjust the distance between the impeller 200 and the screen 210 according to the amount of the input raw material or the type of the raw material.

6a and 6b are cross-sectional views for explaining the operation of the impeller positioning member according to the present invention, Figure 7 shows a plan view of the impeller positioning rod of the device shown in Figs. 6a and 6b.

Referring to FIG. 6A, a drive shaft 240 is installed in the spindle assembly 220, the upper portion of which is fastened to the second pulley 192 and the lower portion of the spindle assembly 220, and the outer peripheral surface of the drive shaft 240 includes a lever. By moving the drive shaft 240 to the upper or lower by using the principle, the impeller position adjustment member 250 that can move the position of the impeller 200 fastened to the drive shaft 240 to the upper or lower is fastened.

The impeller positioning member 250 is a support rod for supporting the central portion of the positioning rod 260, the fixed base 255 fixed on the support plate 110 and the positioning rod 260 as shown in FIG. 295). One side of the positioning rod 260 is hinged to the drive shaft 240 of the lower portion of the second pulley 192, the other side of the positioning rod 260 is formed with a connection hole the fixing rod 255 is such a connection hole By being inserted in, the position adjustment rod 260 is coupled to the fixture 255. An impeller moving member 265 such as a nut is mounted on an upper portion of the fixing rod 255 to which the other side of the positioning rod 260 is fastened, and a thread is formed on the outer circumferential surface of the fixing rod 255.

Accordingly, when the moving member 265 is rotated, the impeller moving member 265 moves downward along the fixing stand 255 to press the other side of the positioning rod 260, and thus one side of the positioning member 260 is moved. It is heard upward by the support 290 by the principle of the lever described above. Therefore, the drive shaft 240 to which the positioning rod 260 is fastened moves upwards, and the impeller 200 bound to the drive shaft 240 also moves upwards, and thus, between the screen 210 and the impeller 200. The gap becomes wider.

On the other hand, as shown in Figure 6b, by rotating the impeller moving member 265 to move the impeller moving member 265 upward along the fixing table 255, the other side of the positioning rod 260 is again the support 290 By moving upwards, one side of the position adjustment rod 260 moves downward. As such, when one side of the positioning rod 260 moves downward, the drive shaft 240 to which the positioning rod 260 is fastened also moves downward. Therefore, the impeller 200 bound to the lower portion of the drive shaft 240 also moves downward, so that the gap between the screen 210 and the impeller 200 is narrowed.

In the above-mentioned grinder, the spacing between the screen and the impeller greatly affects the grinding efficiency of the grinder. However, in the conventional crusher, since the impeller is completely fixed to the drive shaft to grind the raw material while maintaining a constant gap between the impeller and the screen, even if the amount of the raw material or the type of the raw material is different from the initially set screen and impeller It was impossible to change the spacing between. In other words, in order to increase or decrease the distance between the screen and the impeller, the mill was stopped, and then the position of the impeller was forced to be used again.

On the other hand, in the present invention, as described above, because the impeller position adjusting member 250 can easily adjust the distance between the screen 210 and the impeller 200 by changing the position of the impeller 200, the grinder It is possible to change the position of the impeller 200 at any time while the 100 is in operation. Therefore, the distance between the screen 210 and the impeller 200 can be appropriately adjusted according to the type of raw material or the amount of the raw material, so that not only the raw material can be crushed uniformly but also the grinding efficiency of the raw material can be greatly improved. In addition, the time for adjusting the distance between the screen 210 and the impeller 200 can be greatly shortened.

8A and 8B show a perspective view and a cross-sectional view of a screen applied to a conventional grinder, respectively, and FIGS. 9A and 9B show a perspective view and a cross-sectional view of a screen according to an embodiment of the present invention.

Referring to FIGS. 8A and 8B, the conventional general screen 270 drills a plurality of holes 275 in a direction perpendicular to the general metal plate and winds the metal plate on which the holes 275 are formed. That is, in the conventional screen 270, the cross-sections of the holes 275 formed on the outer circumferential surface thereof are smoothly formed without protruding.

However, such a screen 270 is because the surface is smooth, when the raw material is pulverized, it is difficult to generate an effective friction force between the screen 270 and the impeller, thereby reducing the grinding efficiency of the raw material of the pulverized powder Not only the particle diameter is uneven, but also to produce a fine powder having a constant diameter, a problem arises in that the input material is pulverized for a long time. This problem becomes more pronounced when crushing hard raw materials.

However, the screen 210 according to the present invention, as shown in Figures 9a and 9b, a plurality of inclined holes inclined at an angle of about 40 to 50 degrees, preferably about 45 degrees to the side ( 280 is formed, and a periphery of the inclined holes 280 has a structure in which a protrusion of a metal plate is formed toward the inside of the screen 210. That is, since the metal protrusions are formed in the inward direction of the screen 210 along the circumference of the inclined holes 280, the protrusions are positioned between the impeller 200 and the screen 210 installed in the screen 210. In order to install the screen 210 in the impeller housing 135, a flange 290 is formed on an upper portion of the conical screen 210 having an end cut.

In order to manufacture the screen 210, the metal plate is drilled at an angle of about 40-50 degrees, so that a portion of the metal plate protrudes at the periphery of the inclined holes 280. As such, when the metal plate including the inclined holes 280 having protrusions formed on the periphery is wound in a circular shape with an end cut, the screen 210 according to the present invention is manufactured.

In the screen 210 according to the present invention, since metal protrusions are formed at the periphery of the inclined holes 280, the friction force between the impeller 200 and the screen 210 can be generated more effectively, and at the same time, the protrusions alone are used for the raw material. Since the grinding effect can be improved, the raw materials can be pulverized remarkably more efficiently than conventional grinders. In this case, since the protrusions around the inclined holes 280 form a right angle with respect to the impeller 200 rotating in the screen 210, a greatly increased grinding effect can be achieved as compared with the conventional grinder. In particular, the screen 210 according to the present invention can be used more effectively in the case of grinding a solid raw material.

According to the present invention, an impeller positioning member including a positioning rod, a supporter, a supporter, and an impeller moving member applying the principle of the lever is mounted so that the screen and the impeller are operated while the grinder is operated according to the type of raw material or the input amount of the raw material. Since the spacing can be easily adjusted, the uniformity of the raw material powder to be pulverized can be greatly improved and at the same time the efficiency of the pulverizer can be increased.

In addition, by adopting a screen having an inclined hole inclined at an angle of about 40 to 50 ° on the side and an improved structure provided with metal protrusions toward the inside of the screen around the inclined holes, it is possible to effectively grind even when a solid raw material is introduced. In addition to increasing the friction between the screen and the impeller can significantly improve the grinding efficiency of the raw material.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

Claims (16)

In the crusher which establishes raw materials, A frame having a support plate and a plurality of support legs; A control panel installed on one side of the support plate; A hopper mounted on the other side of the support plate; A main panel installed below one side of the support plate; An impeller housing installed at the other lower side of the support plate and equipped with a screen and an impeller therein; And And a drive unit installed between the main panel and the impeller housing and the control panel and the hopper. The method of claim 1, First to fourth support legs are installed on the lower four corners of the support plate, and the first to fourth support legs, characterized in that each of the first to fourth moving member is mounted . The method of claim 2, And the first to fourth moving members are wheels that can be moved and fixed respectively. The method of claim 2, The main panel is installed between the first and second support legs of the lower portion of the support plate, the grinder, characterized in that at least one fixing rod is installed between the third and fourth support legs of the other lower portion of the support plate . The method of claim 1, The drive unit, A drive motor unit mounted between the main panel and the impeller housing; A first pulley installed on the support plate adjacent the control panel; A second pulley installed on the support plate adjacent the hopper; And And a belt mounted between said first and second pulleys. The method of claim 5, An electric motor is installed in the driving motor unit, the shaft of the electric motor is connected to the first pulley, and the second pulley is connected to the impeller so that the electric power of the electric motor is the first pulley, the belt and the second. The grinder characterized in that the transfer to the impeller through a pulley. The method of claim 5, The drive unit further comprises a cover for protecting the first pulley, the second pulley and the belt. The method of claim 1, And the hopper and the impeller housing are connected to each other through a guide member. The method of claim 1, And a support rod installed on one side of the support plate to support the control panel and having a length adjusting means to adjust the height of the control panel. The method of claim 1, And a spindle assembly provided therein with a drive shaft fastened to the impeller in order to transmit a rotational force of the drive unit to the impeller. The method of claim 10, An impeller screw is formed at a lower end of the impeller positioned inside the screen, and a spacer collar is formed between the impeller and the spindle assembly. The method of claim 10, And an impeller position adjusting means for adjusting the position of the impeller to adjust the gap between the impeller and the screen. The method of claim 12, The impeller position adjusting means, Fixing plate formed on the other side of the support plate; A position adjustment rod having one side fastened to the holder and the other side hinged to the drive shaft; A support for supporting a central portion of the positioning rod; And And an impeller moving member configured to move the other side of the positioning rod fastened to the holder in a vertical direction. The method of claim 13, The impeller moving member is a nut, characterized in that the screw thread corresponding to the nut is formed on the outer peripheral surface of the holder. The method of claim 1, Mills, characterized in that the side of the screen is formed with a plurality of inclined holes inclined at an angle of 40 to 50 °. The method of claim 15, And milling protrusions formed in the periphery of the inclined holes, respectively, toward the inside of the screen.