JP7357020B2 - Screw press and liquid content processing method - Google Patents

Description

The present invention relates to a screw press for squeezing a liquid-containing material such as sludge to separate the liquid from the liquid-containing material.

Conventionally, screw presses have been used as devices for squeezing sludge (liquid-containing substances) discharged from liquid processing facilities such as water and sewage treatment plants and human waste treatment plants, and separating water from the sludge (that is, dewatering it). Are known. This screw press includes a filtration tube formed from a perforated plate and a screw placed inside the filtration tube. The screw has a screw shaft arranged concentrically with the filter cylinder and a screw blade fixed to the outer surface of the screw shaft. By rotating the screw blades using a rotation mechanism connected to the screw shaft, the sludge introduced into the filter cylinder is compressed and dehydrated. A back pressure plate that dams up the sludge is placed at the downstream opening end of the filtration tube, and this back pressure plate retains the cake (dehydrated sludge) sent by the rotating screw blades and closes the plug. Form. The cake that forms this plug applies back pressure to the sludge that is fed later, further squeezing the sludge, and thereby lowering the water content of the sludge in the filter cylinder.

Japanese Patent Application Publication No. 2003-126900 Japanese Patent Application Publication No. 2004-249183 Japanese Patent Application Publication No. 2008-6316

The cake, whose moisture content has been reduced by the screw press, becomes hard and is discharged from the screw press as large chunks. However, such large chunks of cake cause a large impact when falling from the discharge port onto the conveyor, causing flight plates and chains of the conveyor to fall off or overloading the conveyor during operation. Another problem was that cake chunks clogged the discharge port and conveyor.

Therefore, the present invention provides a screw press capable of crushing a dehydrated cake discharged from a filter cylinder and a method for treating liquid contents.

In one embodiment, a filtration tube into which a liquid-containing substance is introduced; a screw arranged concentrically with the filtration tube within the filtration tube and transporting the liquid-containing substance toward an outlet of the filtration tube; The crushing device includes a screw motor for rotating the screw, a back pressure plate disposed opposite to the downstream end of the filtration cylinder, and a crushing structure for crushing the plug cake formed by the screw. The structure is provided between the back pressure plate and the downstream end of the filtration tube , is fixed to the downstream end of the filtration tube, and has a plurality of structures arranged concentrically with the filtration tube. A screw press is provided, which is equipped with a crushing blade.

In one embodiment, in the screw press, the tip of the crushing blade faces opposite to the filter cylinder, and the angle of the tip of the crushing blade is within a range of 10 degrees to 150 degrees.

In one aspect, there is provided a method for treating a liquid-containing substance using a screw press that separates a liquid from a liquid-containing substance, wherein the liquid-containing substance is introduced into a filtration cylinder and arranged concentrically with the filtration cylinder within the filtration cylinder. By rotating the screw, the liquid content in the filter tube is transferred toward the outlet of the filter tube, forming a plug cake around the screw axis of the screw, and the liquid content in the filter tube is transferred toward the outlet of the filter tube. The plug cake is removed by a crushing structure that is provided between a back pressure plate disposed facing the downstream end and the downstream end of the filtration cylinder and fixed to the downstream end of the filtration cylinder. and discharging the crushed plug cake from the discharge port , the crushing structure including a plurality of crushing blades arranged concentrically with the filter cylinder, A processing method is provided.

In one embodiment, in the treatment method, the tip of the crushing blade faces opposite to the filter tube, and the angle of the tip of the crushing blade is within a range of 10 degrees to 150 degrees.

According to the present invention, the plug cake discharged from the filter tube is crushed by the crushing structure fixed to the downstream end of the filter tube and broken down into small pieces. Therefore, the load on the conveyor can be reduced and the outlet of the filter tube and the conveyor can be prevented from being clogged.

It is a schematic diagram showing one embodiment of a screw press. FIG. 2 is a schematic diagram of a screw press showing an enlarged crushing structure. FIG. 2 is a front view of the crushing structure shown in FIG. 1. FIG. FIG. 2 is a side view of the crushing structure shown in FIG. 1. FIG. It is a figure showing one embodiment of a crushing blade. FIGS. 6(a) and 6(b) are cross-sectional views of the crushing blade. FIG. 7 is a diagram showing how the crushing structure is crushing the plug cake. It is a figure which shows other embodiment of a crushing blade. It is a figure which shows yet another embodiment of a crushing blade.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing one embodiment of a screw press 1. As shown in FIG. The screw press 1 shown in FIG. 1 includes a cylindrical filtration tube 2, a screw 3 arranged concentrically inside the filtration tube 2, a screw motor 4 for rotating the screw 3, and a downstream end of the filtration tube 2. The device includes a back pressure plate 15 disposed opposite to the back pressure plate 15, and a back pressure plate drive device 16 connected to the back pressure plate 15.

The filter tube 2 is made of a perforated plate such as punched metal. One end of the filter tube 2 is sealed by a closing wall 6, and the other end of the filter tube 2 is connected to a discharge port 8. The input port 7 is formed in the filter tube 2 and is adjacent to the closing wall 6.

The screw 3 includes a screw shaft 3A arranged concentrically with the filter tube 2, and a screw blade 3B fixed to the outer surface of the screw shaft 3A. The screw shaft 3A extends through the filter cylinder 2. The screw shaft 3A has a truncated conical shape whose diameter gradually increases toward the downstream side. The screw shaft 3A extends through the closure wall 6, and the end of the screw shaft 3A is connected to the screw motor 4. The screw motor 4 has a built-in inverter (not shown). The screw motor 4 is connected to a control section 20, and the operation of the screw motor 4, that is, the rotational speed of the screw 3, is controlled by the control section 20.

In one embodiment, the screw press 1 may further include a shaft sliding actuator (not shown) coupled to the screw motor 4. The shaft sliding actuator is configured to move the screw motor 4 in the axial direction of the screw shaft 3A.

The screw blade 3B is a single blade that extends spirally along the longitudinal direction of the screw shaft 3A. A minute gap is formed between the inner surface of the filter tube 2 and the screw blade 3B, and the screw 3 can rotate without contacting the filter tube 2. Sludge introduced into the filter tube 2 from the input port 7 is transferred through the filter tube 2 toward the discharge port 8 by the rotating screw 3 .

A space in which sludge is transferred within the filter tube 2 is formed by the inner surface of the filter tube 2, the screw shaft 3A, and the screw blades 3B. The volume of this space gradually decreases along the direction of movement of the sludge. Therefore, as the sludge is moved through this space by the screw blades 3B, it is compressed and dewatered. The filtrate that has passed through the filter tube 2 is collected by a filtrate receiver 9 disposed below the filter tube 2 and then discharged through a drain 10.

An annular back pressure plate 15 is arranged opposite the downstream end of the filter tube 2 . This back pressure plate 15 has a truncated conical shape with a tapered surface for receiving the dehydrated sludge transferred within the filter tube 2 . A through hole through which the screw shaft 3A passes is formed in the center of the back pressure plate 15, and the back pressure plate 15 is arranged concentrically with the screw shaft 3A. The back pressure plate 15 is not fixed to the screw shaft 3A, and the back pressure plate 15 does not rotate. The sludge dehydrated within the filter cylinder 2 by the rotation of the screw 3 is pressed against the back pressure plate 15 and formed as a plug cake 40.

The back pressure plate 15 is connected to a back pressure plate drive device 16. This back pressure plate drive device 16 is configured to move the back pressure plate 15 in the axial direction of the screw shaft 3A. The gap between the back pressure plate 15 and the downstream end of the filter tube 2 is adjusted by a back pressure plate drive device 16. The back pressure plate drive device 16 is composed of, for example, a hydraulic cylinder or an electric cylinder. The back pressure plate driving device 16 is connected to a control unit 20, and the operation of the back pressure plate driving device 16, that is, the axial position of the back pressure plate 15 is controlled by the control unit 20.

The screw press 1 further includes a crushing structure 30 that crushes the plug cake 40. The crushing structure 30 is provided between the back pressure plate 15 and the downstream end of the filter tube 2 . The crushing structure 30 has a plurality of crushing blades 31 arranged concentrically with the filter tube 2 . A through hole 36 through which the screw shaft 3A passes is formed in the center of the crushing structure 30, and the crushing structure 30 is arranged concentrically with the screw shaft 3A. The crushing structure 30 is fixed to the downstream end of the filter cylinder 2, and the crushing structure 30 does not rotate. As the screw 3 rotates, the plug cake 40 passes through the through hole 36 and is sent toward the back pressure plate 15 little by little. The plug cake 40 discharged from between the filter tube 2 and the back pressure plate 15 is crushed by the crushing blade 31.

FIG. 2 is a schematic diagram of the screw press 1 showing the crushing structure 30 in an enlarged manner. FIG. 3 is a front view of the crushing structure 30 shown in FIG. 1. FIG. 4 is a side view of the crushing structure 30 shown in FIG. 1. The crushing structure 30 of this embodiment includes 16 crushing blades 31 arranged concentrically with the filter tube 2 at equal intervals, a cylindrical body 32, and a mounting plate 33. The cylindrical body 32 has an annular shape concentric with the filter tube 2, and a through hole 32a through which the screw shaft 3A passes is formed in the center. The mounting plate 33 has an annular shape concentric with the filter tube 2, and has a through hole 33a formed in the center thereof through which the screw shaft 3A passes. The through hole 36 formed in the center of the crushing structure 30 is composed of through holes 32a and 33a. The outer diameter of the mounting plate 33 is larger than the outer diameter of the cylindrical body 32, and the cylindrical body 32 is concentrically connected to the mounting plate 33.

The 16 crushing blades 31 are connected to a side wall 32b located on the outer periphery of the cylindrical body 32 and an outer surface 33b of the mounting plate 33, and the tip 31a of the crushing blade 31 is connected to the side opposite to the filter cylinder 2. It's suitable. The cutting edge 31b of the crushing blade 31 faces in the axial direction of the crushing structure 30. The crushing blade 31, the cylindrical body 32, and the attachment plate 33 may be joined to each other by a known joining technique such as welding, or the crushing blade 31, the cylindrical body 32, and the attachment plate 33 may be an integral structure. It's okay. In this embodiment, 16 crushing blades 31 are provided, but the present invention is not limited to this, and the number may be less than 16 or more than 16.

The attachment plate 33 is further formed with a hole 33c for attachment to the filter tube 2. As shown in FIG. 2, the crushing structure 30 is fixed to the downstream end of the filter tube 2. The filter tube 2 has a flange portion 2a surrounding its downstream end. The bolt 34 passes through a hole 33c formed in the mounting plate 33 and a hole (not shown) formed in the flange portion 2a, and is screwed into a nut 35. The hole in the flange portion 2a is formed at a position corresponding to the hole 33c in the mounting plate 33. In this embodiment, the number of holes 33c of the mounting plate 33 and the holes of the flange portion 2a are eight, and the number of connection points by bolts 34 and nuts 35 is eight, but these numbers are not particularly limited. By disengaging the bolt 34 and nut 35, the crushing structure 30 can be removed from the filter tube 2.

As shown in FIG. 5, the tip 31a of the crushing blade 31 has an angle θ. This angle θ is an angle formed by the outer side 31c of the crushing blade 31 and one side forming the cutting edge 31b. The angle θ of the tip 31a of the crushing blade 31 may be within the range of 10 degrees to 150 degrees. The angle θ may be set along the truncated conical inclined surface of the back pressure plate 15 (see FIG. 2). The cutting edge 31b may have an acute-angled cross section to facilitate crushing the plug cake 40, as shown in FIGS. 6(a) and 6(b). The cross section of the cutting edge 31b shown in FIG. 6(a) is inclined from both sides of the crushing blade 31 toward the center of the crushing blade 31 in the thickness direction. The cross section of the cutting edge 31b shown in FIG. 6(b) is inclined from one side of the crushing blade 31 toward the other side.

Next, the operation of the screw press 1 will be explained. As shown in FIG. 1, sludge to be treated is introduced into the filter cylinder 2 from the input port 7. The sludge is transferred through the filter tube 2 toward the discharge port 8 by the rotating screw 3 . As the sludge is moved through the filter tube 2, it is squeezed and dewatered. The filtrate that has passed through the filter cylinder 2 is collected by a filtrate receiver 9 and discharged through a drain 10. The sludge is dehydrated in the filter tube 2 to form a cake.

The cake that has moved inside the filter tube 2 is pressed against the back pressure plate 15. The cake is compressed by being prevented from moving by the back pressure plate 15. This compressed cake forms a plug cake 40 that seals the downstream end of the filter tube 2. The plug cake 40 reduces the moisture content of the cake in the filter tube 2 by applying back pressure to the following cake. While forming a plug cake 40 in the filter tube 2, the cake is pushed by the following cake, passes through the gap between the back pressure plate 15 and the downstream end of the filter tube 2, and is then screwed out from the discharge port 8. It is discharged to the outside of the press 1.

FIG. 7 is a diagram showing how the crushing structure 30 is crushing the plug cake 40. The plug cake 40 extruded from the filter tube 2 is crushed in the axial direction of the crushing structure 30 by the crushing blades 31 of the crushing structure 30 . The plug cake 40 is extruded into the space between two adjacent crushing blades 31 and then discharged to the discharge port 8. The amount of plug cake 40 discharged from the filter tube 2 is adjusted by adjusting the gap between the back pressure plate 15 and the downstream end of the filter tube 2 using the back pressure plate drive device 16 (see FIG. 1). be able to.

The cake discharged from the discharge port 8 is transported by a conveyor arranged below the discharge port 8. According to the present embodiment, the plug cake 40 is discharged while being crushed into small pieces, so that it is possible to prevent a large impact from being applied when falling onto the conveyor, and further to prevent clogging of the discharge port 8 and the conveyor. In this embodiment, in which the number of crushing blades 31 is 16, the width of the crushed plug cake 40 can be reduced to about 20 cm.

FIG. 8 is a diagram showing another embodiment of the crushing blade 31. The crushing blade 31 shown in FIG. 8 has cutting edges 31b-1, 31b-2, and 31b-3. The cutting edges 31b-1 and 31b-3 are formed by sides that are inclined with respect to the outer side 31c of the crushing blade 31. The cutting edge 31b-2 is constituted by a side parallel to the outer side 31c of the crushing blade 31. The tip 31a of the crushing blade 31 has an angle θ. This angle θ is an angle formed by the outer side 31c of the crushing blade 31 and one side forming the cutting edge 31b-1. The angle θ of the tip 31a of the crushing blade 31 may be within the range of 10 degrees to 150 degrees.

The cutting edges 31b-1 and 31b-3 may be inclined with respect to the outer edge 31c along the truncated conical inclined surface of the back pressure plate 15. As a result, when the back pressure plate 15 is moved toward the filtration tube 2 side by the back pressure plate driving device 16 (see FIG. 1), the truncated conical inclined surface of the back pressure plate 15 and the cutting edge 31b-3 of the crushing blade 31 are connected. can be placed so that they are facing each other. As shown in FIGS. 6(a) and 6(b), the cutting edges 31b-1, 31b-2, and 31b-3 may have acute-angled cross sections to facilitate crushing the plug cake. good.

FIG. 9 is a diagram showing still another embodiment of the crushing blade 31. The crushing blade 31 shown in FIG. 9 has cutting edges 31b-1, 31b-2, 31b-3, and 31b-4. The cutting edge 31b-1 is constituted by a side perpendicular to the outer side 31c of the crushing blade 31. The cutting edges 31b-2 and 31b-4 are formed by sides that are inclined with respect to the outer side 31c of the crushing blade 31. The cutting edge 31b-3 is constituted by a side parallel to the outer side 31c of the crushing blade 31. The tip 31a of the crushing blade 31 has an angle θ. This angle θ is an angle formed by the outer side 31c of the crushing blade 31 and one side forming the cutting edge 31b-1. In this embodiment, the angle θ of the tip 31a of the crushing blade 31 is 90 degrees. Thereby, the risk of the crushing blade 31 being worn out and deteriorating can be reduced compared to the case where the tip 31a of the crushing blade 31 is at an acute angle.

The cutting edges 31b-2 and 31b-4 may be inclined with respect to the outer side 31c along the truncated conical inclined surface of the back pressure plate 15. As a result, when the back pressure plate 15 is moved toward the filtration tube 2 side by the back pressure plate driving device 16 (see FIG. 1), the truncated conical inclined surface of the back pressure plate 15 and the cutting edge 31b-4 of the crushing blade 31 are aligned. can be placed so that they are facing each other. The cutting edges 31b-1, 31b-2, 31b-3, and 31b-4 have acute-angled cross sections to facilitate crushing the plug cake, as shown in FIGS. 6(a) and 6(b). You may do so.

The screw press of the embodiment described above is used to separate water, which is a liquid, from sludge, which is an example of a liquid containing material, but this screw press is used to separate liquid from liquid containing materials other than sludge. May be used. For example, the screw press according to the above-described embodiment can also be used for processing food products such as fruit and oil, and processing industrial products such as recycling waste paper. In food processing, screw presses are used to squeeze raw materials (liquid content) such as fruits and seeds to separate liquids such as fruit juice and oil from the raw materials. In waste paper recycling, waste paper is mixed with liquids such as water and chemicals to loosen it into fibrous materials. A screw press is used to squeeze a mixture of fibrous material and liquid (liquid content) to separate the fibrous material from the mixture.

The embodiments described above have been described to enable those skilled in the art to carry out the invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the invention is not limited to the described embodiments, but is to be construed in the broadest scope according to the spirit defined by the claims.

1 Screw press 2 Filtration tube 2a Flange portion 3 Screw 3A Screw shaft 3B Screw blade 4 Screw motor 6 Closure wall 7 Inlet 8 Outlet 9 Filtrate receiver 10 Drain 15 Back pressure plate 16 Back pressure plate drive device 20 Control unit 30 Crushing structure Body 31 Crushing blade 31a Tip 31b Cutting edge 31c Outer side 32 Cylindrical body 32a Through hole 32b Side wall 33 Mounting plate 33a Through hole 33b Outer surface 33c Hole 34 Bolt 35 Nut 36 Through hole 40 Plug cake

Claims (4)

a filtration cylinder into which the liquid content is introduced;
a screw disposed within the filtration tube concentrically with the filtration tube and transporting the liquid content toward the outlet of the filtration tube;
a screw motor that rotates the screw;
a back pressure plate disposed opposite to the downstream end of the filtration cylinder;
comprising a crushing structure for crushing the plug cake formed by the screw,
The crushing structure is provided between the back pressure plate and the downstream end of the filtration tube , is fixed to the downstream end of the filtration tube, and is arranged concentrically with the filtration tube. A screw press equipped with multiple crushing blades . The tip of the crushing blade faces opposite to the filter cylinder,
The screw press according to claim 1 , wherein the angle of the tip of the crushing blade is within a range of 10 degrees to 150 degrees. A method for processing liquid-containing materials using a screw press for separating liquid from liquid-containing materials, the method comprising:
Pour the liquid content into the filter tube,
By rotating a screw arranged concentrically with the filter tube within the filter tube, the liquid content in the filter tube is transferred toward the outlet of the filter tube, and the plug cake is transferred to the screw. formed around the screw shaft of
A crushing structure provided between a back pressure plate disposed to face the downstream end of the filtration tube and the downstream end of the filtration tube, and fixed to the downstream end of the filtration tube. breaking up the plug cake by;
discharging the crushed plug cake from the discharge port ;
The processing method , wherein the crushing structure includes a plurality of crushing blades arranged concentrically with the filter cylinder . The tip of the crushing blade faces opposite to the filter cylinder,
The processing method according to claim 3 , wherein the angle of the tip of the crushing blade is within a range of 10 degrees to 150 degrees.

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