JP2021115590A - Screw press and method for washing screw press - Google Patents

Abstract

To provide a screw press that can reliably prevent washing liquid from leaking out from a cake discharge part.SOLUTION: A screw press includes: a filtration cylinder 1; a filtrate receiver 38; a first screw 3 and a second screw 4; a receiving part 101 for receiving washing liquid jetted from a filtration cylinder washing device 150; a liquid discharge pipe 102 for transporting the washing liquid, which is received by the receiving part 101, to the filtrate receiver 38. The receiving part 101 is disposed while being adjacent to a discharge side end part 110 of the filtration cylinder 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a screw press that squeezes a liquid-containing material such as sludge to separate the liquid from the liquid-containing material. Furthermore, the present invention relates to a method for cleaning a screw press.

Conventionally, a screw press has been used as a device for squeezing sludge (liquid-containing matter) discharged from a liquid treatment facility such as a water and sewage treatment plant and a urine treatment plant to separate (that is, dehydrate) water from the sludge. Are known.

The screw press includes a filter tube formed of a screen (perforated plate) and a screw arranged inside the filter tube. The screw squeezes the sludge put into the filter tube and dehydrates it. The dehydrated sludge (cake) is discharged from the discharge side end of the filtration tube. It is desirable that the cake is discharged from the discharge side end of the filtration tube in a state where the water content is as low as possible.

Japanese Unexamined Patent Publication No. 2010-253536 Japanese Unexamined Patent Publication No. 2018-15582

The screw separates the water from the sludge by pressing the sludge against the filter tube, which can cause clogging of the filter tube. Therefore, in order to prevent clogging of the filter tube, the filter tube is regularly cleaned.

However, since the filter cylinder is cleaned by injecting the high-pressure cleaning liquid from the outside to the inside of the filter cylinder, the cleaning liquid flows through the filter cylinder. As a result, the cleaning liquid may flow out from the cake discharge portion at the discharge side end of the filter tube.

Therefore, an object of the present invention is to provide a screw press and a method for cleaning a screw press, which can surely prevent the cleaning liquid from flowing out from the cake discharging portion.

In one aspect, the filter cylinder into which the liquid-containing material is charged, the filtrate receiver arranged below the filter cylinder, and the liquid-containing material are arranged concentrically with the filter cylinder in the filter cylinder to specify the liquid-containing material. The first screw and the second screw to be transferred in the transfer direction of the above, a receiving portion for receiving the cleaning liquid sprayed from the filtration cylinder cleaning device arranged outside the filtration cylinder, and the filtrate received by the receiving portion. Provided is a screw press comprising a drainage pipe for transferring to a receiver, wherein the receiver is located adjacent to the outlet end of the filter tube.

In one aspect, the screw press comprises a ring member to which the receiving portion can be connected, and the receiving portion has an opening connected to a communication hole formed at the lowermost end of the ring member. ..
In one aspect, the screw press comprises a solid-liquid separation screen covering the opening of the receiving portion, the solid-liquid separation screen does not allow the passage of dehydrated sludge separated from the liquid content, said. It is configured to allow the passage of the cleaning liquid jetted from the filter tube cleaning device.
In one aspect, the second screw is arranged downstream of the first screw in the transfer direction, and the first screw and the second screw are directed from the second screw toward the first screw. It is tilted diagonally downward.

In one aspect, the screw press cleaning method is provided. By rotating the first screw, the liquid-containing substance in the filtration tube is transferred to the second screw to form a plug cake around the screw shaft of the second screw, and the plug cake is formed. In this state, the filter tube cleaning device is operated to clean the filter tube.

In one aspect, after cleaning the filter tube, the plug cake is discharged by rotation of the second screw.

The screw press includes a receiving portion for receiving the cleaning liquid and a drainage pipe. Therefore, the screw press can surely prevent the cleaning liquid from flowing out from the cake discharging portion.

It is a schematic diagram which shows the screw press which concerns on one Embodiment. It is the schematic sectional drawing of the 2nd screw shown in FIG. It is a figure which shows the cleaning liquid transfer structure and the cleaning apparatus. It is a figure which looked at the cleaning apparatus from the axial direction of a 1st screw and a 2nd screw. It is a figure which shows the other embodiment of a screw press. It is a figure which shows the receiving part connected to a ring member. It is a figure which shows still another embodiment of a screw press. It is a flowchart which shows the cleaning process of a screw press. It is a schematic diagram for demonstrating the number of turns of a 2nd screw blade.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a screw press according to an embodiment. The screw press shown in FIG. 1 is arranged concentrically with the cylindrical screen casing (filtration cylinder) 1 and the screen casing 1 in the screen casing 1, and sludge (liquid content) is transferred in a predetermined transfer direction D. The first screw 3 and the second screw 4 to be transferred, the first rotating mechanism 7 for rotating the first screw 3, and the second rotating mechanism 20 for rotating the second screw 4 independently of the first screw 3 are provided. I have.

The screen casing 1 is formed of a screen (perforated plate) such as punching metal. A sludge inlet 2 is formed at the upstream end of the screen casing 1. The sludge charged into the screen casing 1 from the charging port 2 is transferred in the screen casing 1 in a predetermined transfer direction D by the rotating first screw 3 and the second screw 4. Further, the screw press has a control unit 6 that controls the operation of the first rotation mechanism 7 and the second rotation mechanism 20.

The second screw 4 is connected to the first screw 3 so that it can rotate independently of the first screw 3. The first screw 3 and the second screw 4 extend through the screen casing 1 and the discharge chamber 33, respectively. The discharge chamber 33 is connected to the screen casing 1. A plug cake, which will be described later, is discharged from the screen casing 1 into the discharge chamber 33. The axial length of the second screw 4 is shorter than the axial length of the first screw.

The first screw 3 is fixed to the outer surface of the first screw shaft 3A having a truncated cone shape (tapered shape) and the first screw shaft 3A whose diameter gradually increases toward the downstream side in the sludge transfer direction D. It has a first screw blade 3B. The second screw 4 has a cylindrical second screw shaft 4A and a second screw blade 4B fixed to the outer surface of the second screw shaft 4A. The second screw 4 is arranged on the downstream side of the first screw 3 in the sludge transfer direction D.

The upstream end of the screen casing 1 is sealed by a closing wall 8. One end of the first screw shaft 3A (upstream end in the transfer direction D) extends through the closing wall 8. A water sealing device 10 for sealing the gap between the closing wall 8 and the first screw shaft 3A is installed on the closing wall 8. The upstream end of the first screw shaft 3A extending through the closing wall 8 is rotatably supported by bearings 11 and 12 installed on the base (not shown) while restraining axial movement. .. One of the bearings 11 and 12 can be omitted.

The upstream end of the first screw shaft 3A is connected to a first rotation mechanism 7 for rotating the first screw 3. In the present embodiment, the first rotation mechanism 7 includes a first drive (for example, an electric motor) 14, a sprocket 15 fixed to the rotation shaft of the first drive 14, and a sprocket fixed to the first screw shaft 3A. A 16 and a chain 17 wound around the sprockets 15 and 16 are provided.

The sprocket 16 is located between the bearings 11 and 12. When the first drive machine 14 of the first rotation mechanism 7 is driven, the sprocket 15 fixed to the rotation shaft of the first drive machine 14 rotates, and the sprocket 16 fixed to the first screw shaft 3A via the chain 17 To rotate. As a result, the first screw 3 is rotated by the first rotation mechanism 7. The first drive unit 14 is connected to the control unit 6, and the control unit 6 is configured to be able to control the operation of the first drive unit 14.

Although not shown, the rotating shaft of the first driving machine 14 may be connected to the first screw shaft 3A via a speed reducer. Alternatively, the rotating shaft of the first driving machine 14 may be directly connected to the first screw shaft 3A.

FIG. 2 is a schematic cross-sectional view of the second screw 4 shown in FIG. As shown in FIG. 2, the second screw shaft 4A has a hollow structure. At the other end of the first screw shaft 3A (downstream end in the transfer direction D), a reduced diameter portion 3C to be inserted into the cylindrical second screw shaft 4A is formed.

By forming the reduced diameter portion 3C on the first screw shaft 3A, a wall surface 3D perpendicular to the axial direction is formed on the first screw shaft 3A. The reduced diameter portion 3C is inserted into the cylindrical second screw shaft 4A and is rotatably supported by the slide bearings 30 and 31 fixed to the inner wall 4C of the second screw shaft 4A. With such a configuration, the first screw 3 is rotatably connected to the second screw 4.

As shown in FIGS. 1 and 2, the second screw shaft 4A of the second screw 4 is arranged concentrically with the first screw shaft 3A. The outer diameter of the second screw shaft 4A is the same as the maximum diameter of the first screw shaft 3A. The second screw shaft 4A is formed with a reduced diameter portion 4F extending through the inner wall 33A of the discharge chamber 33. By forming the reduced diameter portion 4F on the second screw shaft 4A, a wall surface 4D perpendicular to the axial direction is formed on the second screw shaft 4A.

The upstream end of the second screw shaft 4A is rotatably supported by the first screw shaft 3A via the slide bearings 30 and 31, and the downstream end of the second screw shaft 4A is a base (not shown). ), The bearings 22 and 23 are rotatably supported while restraining the movement in the axial direction. The bearing 23 can be omitted.

The downstream end of the second screw shaft 4A is connected to a second rotation mechanism 20 for rotating the second screw 4. In the present embodiment, the second rotation mechanism 20 includes a second drive machine (for example, an electric motor) 24, a sprocket 25 fixed to the rotation shaft of the second drive machine 24, and a sprocket fixed to the second screw shaft 4A. A 26 and a chain 27 wound around these sprockets 25 and 26 are provided.

The sprocket 26 is located between the bearings 22 and 23. When the second drive machine 24 of the second rotation mechanism 20 is driven, the sprocket 25 fixed to the rotation shaft of the second drive machine 24 rotates, and the sprocket 26 fixed to the second screw shaft 4A via the chain 27. To rotate. As a result, the second screw 4 is rotated by the second rotation mechanism 20.

The second drive unit 24 is connected to the control unit 6. The second drive machine 24 has a built-in inverter (not shown), and the control unit 6 is configured to be able to control the operation of the second drive machine 24 via the inverter. That is, the control unit 6 can control the rotation speed and the rotation direction of the second drive machine 24 via the inverter. The second drive machine 24 can rotate the second screw 4 independently of the first screw 3. It is preferable that the first drive machine 14 also has a built-in inverter capable of changing the rotation speed and the rotation direction of the first drive machine 14.

Although not shown, the rotating shaft of the second drive machine 24 may be connected to the second screw shaft 4A via a speed reducer. Alternatively, the rotating shaft of the second drive machine 24 may be directly connected to the second screw shaft 4A.

The first screw blade 3B extends spirally along the axial direction of the first screw shaft 3A, and the second screw blade 4B spirally extends along the axial direction of the second screw shaft 4A. The total length of the portion of the first screw 3 to which the first screw blade 3B is fixed and the portion of the second screw 4 to which the second screw blade 4B is fixed is the axial length of the screen casing 1. Same or longer.

A minute gap is formed between the inner surface of the screen casing 1 and the first screw blade 3B so that the first screw blade 3B can rotate without contacting the screen casing 1. Similarly, a minute gap is formed between the inner surface of the screen casing 1 and the second screw blade 4B, so that the second screw blade 4B can rotate without contacting the screen casing 1. ing.

The sludge charged into the screen casing 1 from the inlet 2 formed at the upstream end of the screen casing 1 is transferred toward the discharge chamber 33 by the rotating first screw blades 3B and the second screw blades 4B (that is, transferred). Can be transferred (in direction D).

In the present embodiment, the winding direction of the second screw blade 4B (that is, the spiral direction) is opposite to the winding direction of the first screw blade 3B. Therefore, when the sludge charged from the charging port 2 is sent out to the discharge chamber 33, the second screw 4 is rotated in the direction opposite to that of the first screw 3, as shown in FIG.

In one embodiment, the winding direction of the second screw blade 4B may be the same as the winding direction of the first screw blade 3B. In this case, when the sludge charged from the charging port 2 is sent out to the discharge chamber 33, the second screw 4 is rotated in the same direction as the first screw 3.

As shown in FIG. 1, the screen casing 1 is divided into a dehydration region 1A in which the first screw 3 is arranged and a plug forming region 1B in which the second screw 4 is arranged. The space to which sludge is transferred in the dehydration region 1A is formed by the inner surface of the screen casing 1, the first screw blade 3B, and the first screw shaft 3A.

As shown in FIG. 1, the cross-sectional area of this transfer space gradually decreases along the sludge transfer direction D. Therefore, as the sludge charged from the charging port 2 is transferred through this transfer space by the first screw blade 3B, the sludge is squeezed and dehydrated. The filtrate that has passed through the screen (perforated plate) of the screen casing 1 is collected by the filtrate receiver 38 arranged below the screen casing 1. A drain 39 is connected to the filtrate receiver 38, and the filtrate collected by the filtrate receiver 38 is discharged from the screw press via the drain 39.

The space to which sludge is transferred in the plug forming region 1B is formed by the inner surface of the screen casing 1, the second screw blade 4B, and the second screw shaft 4A. As shown in FIG. 1, the cross-sectional area of this transfer space is constant. In the plug forming region 1B, the plug cake is formed by the sludge (that is, the cake) dehydrated in the dehydrating region 1A. The method of forming the plug cake will be described later.

As described above, the screen casing 1 is cleaned periodically because the screen casing 1 may be clogged when the filtrate is separated from the sludge. If the cleaning liquid flows out of the discharge chamber 33 (in other words, the cake discharge portion) due to the cleaning of the screen casing 1, the cleaning liquid may be mixed in the cake (that is, the discharge cake) discharged from the discharge chamber 33. As a result, the moisture content of the discharged cake becomes high. From the viewpoint of reducing the cost of disposing of the cake, it is desirable that the cake discharged from the discharge chamber 33 is transported to the outside of the screw press in a state where the water content is as low as possible.

Therefore, this screw press includes a cleaning liquid transfer structure 100 arranged adjacent to the discharge side end 110 of the screen casing 1. The cleaning liquid transfer structure 100 has a structure for transferring the cleaning liquid for cleaning the screen casing 1. Hereinafter, the structure of the cleaning liquid transfer structure 100 and the structure of the cleaning device (that is, the filter tube cleaning device) for cleaning the screen casing 1 will be described with reference to the drawings.

FIG. 3 is a diagram showing a cleaning liquid transfer structure 100 and a cleaning device 150. FIG. 4 is a view of the cleaning device 150 as viewed from the axial direction CL of the first screw 3 and the second screw 4. In FIG. 4, the first screw blade 3B and the second screw blade 4B are not shown.

As shown in FIG. 3, the cleaning liquid transfer structure 100 includes a receiving portion 101 that receives the cleaning liquid ejected from the cleaning device 150, and a drainage pipe 102 that transfers the cleaning liquid collected in the receiving portion 101 to the filtrate receiving 38. , Is equipped. In the embodiment shown in FIG. 3, the receiving portion 101 is attached to the inner wall 33A of the discharge chamber 33 and is arranged below the wall surface 4D of the second screw shaft 4A. In the embodiment shown in FIG. 3, the second screw blade 4B extends to the wall surface 4D of the second screw shaft 4A, and the rear end 4B-1 of the second screw blade 4B extends to the wall surface 4D of the second screw shaft 4A. It is connected.

One end of the drainage pipe 102 is connected to the lower part of the receiving portion 101, and the other end is arranged above the filtrate receiving 38 through the inner wall 33A of the draining chamber 33. Therefore, the cleaning liquid collected in the receiving portion 101 is transferred to the filtrate receiving 38 through the drain pipe 102, and is discharged from the screw press through the drain 39.

As shown in FIGS. 3 and 4, the cleaning device 150 includes a plurality of cleaning nozzles 152 arranged outside the screen casing 1 (more specifically, outside in the radial direction). In the embodiment shown in FIG. 4, a plurality of cleaning nozzles 152 are arranged at equal intervals along the circumferential direction of the screen casing 1. The number of cleaning nozzles 152 is not limited to the embodiment shown in FIG. At least one cleaning nozzle 152 may be arranged. In the embodiment shown in FIG. 4, the plurality of cleaning nozzles 152 are connected to a cleaning liquid supply pipe (not shown) to which the cleaning liquid is supplied, and the injection port of each cleaning nozzle 152 faces the screen casing 1.

When the cleaning device 150 is operated, the cleaning liquid is sprayed from the outside to the inside of the screen casing 1 to remove sludge from a large number of holes formed in the screen casing 1. The cleaning device 150 (more specifically, the cleaning nozzle 152) moves along the axial direction CL in a state where the cleaning liquid is sprayed, and cleans the entire screen casing 1.

As shown in FIG. 3, when the screw press is divided into a filtrate separation region B1 for separating the filtrate from the sludge and a sludge discharge region B2 for discharging the dehydrated sludge, the receiving portion 101 receives the sludge. Arranged in the discharge region B2, the drainage pipe 102 extends from the sludge discharge region B2 toward the filtrate separation region B1. The cleaning liquid transfer structure 100 having such a structure receives the cleaning liquid flowing through the screen casing 1 by the receiving portion 101, and separates the cleaning liquid received by the receiving portion 101 from the sludge discharge region B2 by the drainage pipe 102. It can be returned to the area B1.

FIG. 5 is a diagram showing another embodiment of the screw press. In the present embodiment, the same or corresponding members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted. As shown in FIG. 5, the screw press may include a ring member 50 to which the receiving portion 101 can be connected. The ring member 50 is fixed to the inner wall 33A of the discharge chamber 33 so as to surround the wall surface 4D of the second screw 4. In the embodiment shown in FIG. 5, the rear end 4B-1 of the second screw blade 4B of the second screw 4 does not protrude from the ring member 50. In one embodiment, the rear end 4B-1 of the second screw blade 4B may protrude from the ring member 50 in order to ensure that the cake is discharged into the discharge chamber 33.

FIG. 6 is a diagram showing a receiving portion 101 connected to the ring member 50. As shown in FIGS. 5 and 6, the receiving portion 101 of the cleaning liquid transfer structure 100 is connected to the lowermost end 50a of the ring member 50. In the embodiment shown in FIGS. 5 and 6, the cleaning liquid transfer structure 100 includes a solid-liquid separation screen 103 that covers the opening 101a of the receiving portion 101. As an example of the solid-liquid separation screen 103, a net member or a perforated plate (for example, punching metal) can be mentioned.

A communication hole 51 through which the cleaning liquid flows is formed at the lowermost end 50a of the ring member 50, and the opening 101a of the receiving portion 101 is connected to the communication hole 51 of the ring member 50. The cleaning liquid ejected from the cleaning device 150 is collected at the lowermost end 50a of the ring member 50, and is collected at the receiving portion 101 through the communication hole 51. The solid-liquid separation screen 103 allows the cleaning liquid to pass through while capturing the cake separated from the sludge.

Therefore, the cleaning liquid passes through the solid-liquid separation screen 103, and then is transferred to the filtrate receiver 38 through the drainage pipe 102. Since the solid-liquid separation screen 103 does not allow the passage of the cake separated from the sludge, the cake is discharged from the discharge chamber 33. In one embodiment, the cleaning liquid transfer structure 100 provided with the solid-liquid separation screen 103 may be applied to the embodiments shown in FIGS. 1 to 4.

FIG. 7 is a diagram showing still another embodiment of the screw press. In the present embodiment, the same or corresponding members as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted. In the embodiment shown in FIG. 7, the first screw 3 and the second screw 4 are inclined obliquely downward from the second screw 4 toward the first screw 3. The screen casing 1 is also tilted at the same tilt angle as the first screw 3 and the second screw 4. In the embodiment shown in FIG. 7, the entire screw press is inclined diagonally downward.

In the embodiment shown in FIG. 7, the cleaning liquid jetted from the cleaning device 150 positively flows toward the first screw 3, that is, in the direction opposite to the transfer direction D, so that the screw press receives the receiving portion 101. The amount of cleaning liquid recovered can be reduced. In the embodiment shown in FIG. 7, the cleaning liquid transfer structure 100 may also include a solid-liquid separation screen 103 (see FIGS. 5 and 6).

Next, the method for cleaning the screw press according to the above-described embodiment will be described with reference to the drawings. FIG. 8 is a flowchart showing a cleaning process of the screw press. As shown in step S101 of FIG. 8, the control unit 6 drives the first rotation mechanism 7 to rotate the first screw 3 while the second screw 4 is stopped. Next, sludge is charged into the screen casing 1 from the charging port 2 (see FIG. 1). The sludge charged from the charging port 2 is transferred toward the second screw 4 (that is, in the transfer direction D) by the rotating first screw blade 3B without staying in place.

The sludge is squeezed as it is transferred through the dehydration region 1A, and the liquid contained in the sludge is filtered by the screen casing 1. While the sludge is transferred through the dehydration region 1A of the screen casing 1, the sludge is dehydrated into a cake and sent to the plug forming region 1B where the second screw 4 is arranged.

At the beginning of operation, since the second screw 4 is not rotating (that is, stopped), the cake in the plug forming region 1B is not discharged to the discharge chamber 33, but stays in the plug forming region 1B. The cake is gradually accumulated on the second screw 4 and pressed against the second screw blade 4B by sludge (hereinafter referred to as “subsequent cake”) transferred from the dehydration region 1A to the plug forming region 1B.

The cake in the plug forming region 1B is squeezed by being hindered from moving by the second screw blade 4B, and becomes a cake having a low water content. This low water content cake forms a plug cake that impedes subsequent cake movement (see step S102 in FIG. 8). Back pressure is applied to the subsequent cake by the plug cake formed around the second screw shaft 4A, and the subsequent cake is further squeezed. The liquid separated from the plug cake in the plug forming region 1B is collected by the filtrate receiver 38 and discharged from the screw press via the drain 39.

As the operation of the screw press is continued, the plug cake is uniformly formed over the entire circumference of the second screw shaft 4A. As a result, a plug cake that reliably dams the subsequent cake is formed around the second screw shaft 4A. Therefore, even when the water content of the subsequent cake is high, the plug cake formed in the plug forming region 1B can reliably block the subsequent cake, so that one-sided flow of the subsequent cake can be prevented. This "one-sided flow" means that a subsequent cake having a higher water content than the plug cake passes through the plug forming region 1B as it is and is discharged to the discharge chamber 33.

After forming the plug cake, as shown in step S103 of FIG. 8, the control unit 6 drives the second rotation mechanism 20 to rotate the second screw 4 and drive the cleaning device 150. After that, the control unit 6 moves the cleaning device 150 in the axial direction CL to the discharge side end 110 of the screen casing 1 in a state where the cleaning liquid is sprayed from the cleaning nozzle 152 of the cleaning device 150.

In this way, the cleaning device 150 cleans the screen casing 1 during the operation of the screw press (see step S104). More specifically, the control unit 6 rotates the second screw 4 in the direction opposite to the rotation direction of the first screw 3, and gradually discharges the plug cake from the discharge chamber 33 by the second screw blade 4B. The cleaning device 150 is operated to clean the screen casing 1.

In the embodiment shown in FIG. 8, since the cleaning device 150 cleans the screen casing 1 with the plug cake formed, the passage of the cleaning liquid is hindered by the plug cake. Therefore, the method of cleaning the screen casing 1 with the plug cake formed in this way can surely prevent the cleaning liquid from being mixed into the discharge cake, that is, the cleaning liquid from flowing out from the discharge chamber 33.

In the embodiment shown in FIG. 8, a method of cleaning the screen casing 1 during the operation of the screw press with the plug cake formed has been described, but in one embodiment, the screw press with the plug cake formed has been described. Cleaning of the screen casing 1 may be performed at the end of the operation. In this case, the control unit 6 does not necessarily have to operate the cleaning device 150 with the first screw 3 and the second screw 4 rotated, and after forming the plug cake, the first screw 3 and the second screw 3 and the second screw 4 do not necessarily operate. The cleaning device 150 may be operated with the screw 4 stopped. In this case, after cleaning the screen casing 1, the control unit 6 rotates the second screw 4 to discharge the plug cake from the discharge chamber 33.

In one embodiment, the screen casing 1 may be washed without forming a plug cake. In this case, the control unit 6 moves the cleaning device 150 in the axial direction while injecting the cleaning liquid, and at least before the last winding of the second screw blade 4B, the cleaning liquid is injected and the cleaning device 150 is moved. Stop one operation. Hereinafter, the winding of the screw blade will be described with reference to the drawings.

FIG. 9 is a schematic view for explaining the number of turns of the second screw blade 4B. As shown in FIG. 9, the number of turns of the second screw blade 4B extending spirally is one when the second screw blade 4B advances 360 ° around the first screw shaft 4A from the start point S1 to the point S2. And count. In the second screw 4 shown in FIG. 9, the number of turns of the second screw blade 4B is two. Therefore, in FIG. 9, the control unit 6 stops at least one operation of injecting the cleaning liquid and moving the cleaning device 150 at the position of the point S2.

The above-described embodiment is described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present 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 present invention is not limited to the described embodiments, but is construed in the broadest range according to the technical idea defined by the claims.

1 Screen casing 1A Dehydration area 1B Plug formation area 2 Input port 3 1st screw 3A 1st screw shaft 3B 1st screw blade 3C Reduced diameter part 3D Wall surface 4 2nd screw 4A 2nd screw shaft 4B 2nd screw blade 4B-1 Rear end 4C Inner wall 4D Wall surface 4F Reduced diameter part 6 Control unit 7 1st rotation mechanism 8 Closure wall 10 Water sealing device 11, 12 Bearing 14 1st drive 15, 16 Sprocket 17 Chain 20 2nd rotation mechanism 22, 23 Bearing 24 2nd drive machine 25, 26 Sprocket 27 Chain 30, 31 Slide bearing 33 Drainage chamber 38 Sewage receiver 39 Drain 50 Ring member 50a Bottom end 51 Communication hole 100 Cleaning liquid transfer structure 101 Receiving part 101a Opening 102 Drainage pipe 103 Solid liquid Separation screen 110 Discharge side end 150 Cleaning device 152 Cleaning nozzle

Claims (6)

The filter tube into which the liquid content is charged and
With the filtrate receiver arranged below the filter tube,
In the filter tube, the first screw and the second screw, which are arranged concentrically with the filter tube and transfer the liquid-containing material in a predetermined transfer direction,
A receiving portion that receives the cleaning liquid sprayed from the filtration cylinder cleaning device arranged on the outside of the filtration cylinder, and
A drainage pipe for transferring the cleaning liquid received in the receiving portion to the filtrate receiving portion is provided.
The receiving portion is a screw press arranged adjacent to the discharge side end portion of the filtration cylinder. The screw press includes a ring member to which the receiving portion can be connected.
The screw press according to claim 1, wherein the receiving portion has an opening connected to a communication hole formed at the lowermost end of the ring member. The screw press includes a solid-liquid separation screen that covers the opening of the receiving portion.
The solid-liquid separation screen is configured to not allow the passage of dehydrated sludge separated from the liquid content, but to allow the passage of the cleaning liquid jetted from the filter tube cleaning device, claim 1 or The screw press according to claim 2. The second screw is arranged on the downstream side of the first screw in the transfer direction.
The screw press according to any one of claims 1 to 3, wherein the first screw and the second screw are inclined obliquely downward from the second screw toward the first screw. The method for cleaning a screw press according to any one of claims 1 to 4.
By rotating the first screw, the liquid-containing material in the filtration tube is transferred to the second screw to form a plug cake around the screw shaft of the second screw.
A method of cleaning the filter tube by operating the filter tube cleaning device in a state where the plug cake is formed. The method according to claim 5, wherein after cleaning the filter tube, the plug cake is discharged by rotation of the second screw.

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