Filter press filter cloth damage detection device

Abstract

To provide a filter cloth breakage detection device in a filter press that can detect breakage of a filter cloth with good accuracy during operation of the filter press.SOLUTION: A filter cloth breakage detection device in a filter press comprises: detectors 17, 22 in which filtrate discharged from each filtration chamber 9 is collected and which linearly communicate with each other; and a detection device 18 which transmits irradiation waves reflected at an interface between a filtrate with specified turbidity and a clear filtrate from ends of the detectors 17, 22, and converts a propagation time until reception of the irradiation waves into a distance and outputs the same. The filter cloth detection device can linearly and longitudinally detect which filter cloth 6 in the parallel filtration chambers 9 is broken by one measuring instrument.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filter cloth damage detection device for a filter press that detects which filter cloth is damaged based on the filtrate discharged from a filter press having a plurality of filtration chambers arranged in parallel. [Background technology]

[0002] In conventional filter presses, the filtrate separated by the filter cloth in each filtration chamber is discharged to an external filtrate tank or the like via a common discharge path provided on the outer side of each filter plate. Therefore, even if a filter cloth is damaged and filtrate containing a large amount of suspended solids is discharged, it is unclear which of the many filter cloths is damaged, so operation has been stopped and the filter cloths in each filtration chamber have been visually identified. However, with this method, it is unclear which filter cloth is damaged, and inspection is time-consuming.

[0003] Furthermore, if operation continues without noticing the damage to the filter cloth, the pressure cannot be maintained in the filtration chamber with the damaged filter cloth, resulting in an imbalance in the pressure being forced into the filtration chambers of the entire filter press, making sufficient dewatering impossible. The filtrate containing a large amount of suspended solids is discharged to the outside, increasing the environmental impact. Furthermore, filtrate containing a large amount of suspended solids from the filter floor surface concentrates in the connecting holes and flows into the discharge channel at high dynamic pressure (high speed), causing wear to the connecting holes and discharge channel, especially due to the hard particles in the suspended solids, and requiring part replacement.

[0004] Patent Document 1 discloses a filter cloth damage detection device for a filter press in which the lower part of each filtrate discharge pipe communicating with a filtration chamber is branched into two branch pipes, a three-way valve is provided at the branch, a turbidity meter is installed in one branch pipe, and the other branch pipe is connected to a common collecting pipe, as shown in Figure 1. Also, Figure 3 discloses a filter cloth damage detection device for a filter press in which the lower part of each filtrate discharge pipe communicating with a filtration chamber is branched into two branch pipes, a three-way valve is provided at the branch, one branch pipe is connected to a common collecting pipe, and the other branch pipe is connected to a common branch pipe, and turbidity is measured with a turbidity meter.

[0005] Patent Document 2 discloses a filter cloth damage detection device for a filter press in which a remote detection device consisting of a transmission type optical sensor is placed on the side of a filter plate row, and when the filter cloth is damaged and the detection rod protrudes to the side of the filter plate, the light beam from the optical sensor is blocked and an alarm is activated. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Utility Model Application Publication No. 58-116005 [Patent Document 2] Patent No. 5582359 Summary of the Invention [Problem to be solved by the invention]

[0007] The technology shown in Figure 1 of Patent Document 1 requires a turbidity meter for each filtration chamber, which increases costs and the risk of breakdowns and malfunctions. The technology shown in Figure 3 of Patent Document 1 requires only one turbidity meter, but requires switching the filtrate discharged from each filtration chamber using a three-way valve and checking each one individually. It also takes time and effort to identify damaged filter cloths.

[0008] The technology in Patent Document 2 detects damage to filter cloths using an optical sensor that shines light along the filter plate row, but requires a detection rod that protrudes from each filter plate when damaged, which increases costs and the risk of malfunctions.In addition, to identify damaged filter cloths, it is necessary to visually check which filter plate the detection rod protrudes from.

[0009] The present invention provides a filter cloth damage detection device for a filter press that can detect filter cloth damage with high accuracy while the filter press is in operation and can identify which filter cloth in parallel filtering chambers has been damaged using a single measuring instrument. [Means for solving the problem]

[0010] The present invention relates to a filter press in which filtrate separated into solid and liquid by filter cloths sandwiched between filter plates is discharged into a collecting pipe through the filtrate passages of each filter plate. The filter press comprises a linearly communicating detection path in which the filtrate discharged from each filtration chamber is collected; Filtrate flows down Detection path upstream end and a detection device that emits an irradiation wave that is reflected at the interface between a filtrate of a specified turbidity and a clear filtrate, and converts the propagation time until the reflected wave is received into a distance and outputs the converted distance. This allows for highly accurate detection of damage to the filter cloth and easy identification of the damaged filter cloth.

[0011] The detection path is a collecting pipe formed when the drain outlets of each filter plate are connected to each other along the arrangement direction by closing the filter plates, or a collecting pipe installed alongside each filter plate.If the detection device is installed at the upstream end where the filtrate flows down, it is easy to improve existing devices and the distance can be accurately detected even if sewage flows downstream.

[0012] When the detection path is formed by connecting a part of the filtrate passage of each filter plate by closing the filter plates, the irradiation wave is emitted perpendicular to the flow direction of the filtrate, so that the position can be detected accurately.

[0013] High concentration filtrate can be detected in the collecting pipe by irradiating the irradiation wave near the connection between the detection path and the filtrate passage and installing a downflow prevention plate that allows the irradiation wave to pass through on the upstream side of the connection between the detection path and the filtrate passage, or by installing a downflow guide pipe consisting of a T-pipe at the connection between the detection path and the filtrate passage and aligning the opening of the T-pipe with the upstream and downstream sides of the collecting pipe and irradiating the irradiation wave from the detection device into the inside of it. [Effects of the Invention]

[0014] The filter cloth damage detection device for a filter press according to the present invention is configured as described above, and can identify which filter cloth in a plurality of parallel filtration chambers has been damaged during operation using a single measuring device. There is no need to stop the filter press for inspection, open the filter plates, and visually check. Furthermore, there is no need for complicated operations such as switching the filtrate, and detection is easy. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic side view of a filter press according to the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is a schematic explanatory diagram of detection along a detection path. [Figure 5] FIG. 10 is a schematic explanatory diagram of detection using a detection path according to another embodiment 1. [Figure 6] FIG. 10 is a schematic explanatory diagram of detection using a detection path according to another embodiment 2. [Figure 7] FIG. 10 is a schematic side view of a filter press according to another embodiment 3. [Figure 8] FIG. 10 is a front view of a filter plate according to another embodiment 3. DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a schematic side view of a filter press according to the present invention. The filter press 1 according to the present invention is mounted on a pair of parallel guide rails 4 supported by a front frame 2 and a rear frame 3. A plurality of filter plates 5 having filtering floor surfaces 5a on the front and back sides, and filter cloths 6 stretched over the filtering floor surfaces 5a, are attached to the guide rails 4. The plurality of filter plates 5... are mounted on the guide rails 4 so as to be movable forward and backward.

[0017] An opening / closing device 7 is supported on the rear frame 3, and the filter plates 5 are closed by extending the opening / closing device 7 and pressing the movable head 8 toward the front frame 2. When raw liquid is supplied to the filtration chamber 9 between the closed filter plates 5, 5, the raw liquid undergoes solid-liquid separation by the filter cloth 6, and the solid matter captured by the filter cloth 6 is dewatered while forming a cake layer within the filtration chamber 9. The filtrate passes through the filter cloth 6 and is discharged to the outside from the filtrate passage 10 on the filtering floor surface 5a.

[0018] After dewatering is completed, the opening and closing device 7 is contracted to open the filter plates 5. The filter plates 5 can be opened simultaneously at predetermined intervals determined by the connecting links 11. The cake in the filtering chamber 9 is then dropped and discharged outside the machine. The opening and closing device 7 for opening and closing the filter plates 5 can be a hydraulic cylinder, an electric cylinder, or the like. Alternatively, the filter plates 5 may be opened one by one in sequence.

[0019] FIG. 2 is a schematic cross-sectional view of the filtration chamber. Each filter plate 5... has a concave filtration floor surface 5a. When the filter plates 5 are closed, the filtration floor surfaces 5a define filtration chambers 9 between the opposing filtration floor surfaces 5a of adjacent filter plates 5. When raw liquid is supplied from the raw liquid supply path 12 through the raw liquid passage 13 between the filter cloths 6, 6 of the filtration chamber 9, the raw liquid undergoes solid-liquid separation by the filter cloth 6, and the filtrate that passes through the filter cloth 6 flows into the filtrate passage 10 provided below the filtration floor surface 5a. If the filter cloth 6 is damaged during this process, solids will pass through the damaged area of ​​the filter cloth 6 and flow into the filtrate passage 10 along with the filtrate. By configuring one of the filtration floor surfaces 5a as a diaphragm, the filtration chamber 9 is compressed by the diaphragm during solid-liquid separation, reducing the moisture content of the solids.

[0020] FIG. 3 is a front view of the filter plate. One end of a filtrate passage 10 for discharging filtrate is open below the filter floor surface 5a where the filtrate collects. The passage 10 passes through the thickness of the filter plate 5 and connects to a drain port 14 formed on the outer side of the filter plate 5 at the other end. The drain port 14, which is connected to the filtrate passage 10, is provided so as to penetrate the filter plate 5 in the thickness direction. When the filter plate 5 is closed, the drain ports 14 of each filter plate 5 are connected to each other along their arrangement direction to form a collecting pipe 15. The filtrate separated into solid and liquid in each filtration chamber 9 is discharged from each filtrate passage 10 through the collecting pipe 15 and to the outside through a discharge pipe 16 connected to the front frame 2. In this way, a large amount of filtrate separated into solid and liquid by the filter cloth 6 is pressurized by a diaphragm or the like, and flows from the filtrate passage 10 to the drain port 14 and then down the collecting pipe 15 toward the front frame 2.

[0021] In this embodiment, the filtrate passages 10 are arranged symmetrically on adjacent filter plates 5, 5, and the filtrate is discharged to the drain ports 14 located on both outer sides of the filter plate 5, respectively. However, the filtrate passages 10 of each filter plate 5 may be connected to only one of the drain ports 14 or to the drain ports 14 on both outer sides. In addition, in this embodiment, the collecting pipe 15 is configured to be integrated with the filter plate 5. As shown in Figures 7 and 8, A collecting pipe 15a independent of the row of filter plates 5 may be provided in parallel, and the filtrate may be discharged from each filtering chamber 9 to the collecting pipe 15a via a flexible tube or the like.

[0022] FIG. 4 is a schematic explanatory diagram of detection along a detection path. The filtrate discharged from each filtration chamber 9 is collected in a common detection path 17, and the position of the suspension that has flowed into the detection path 17 is measured by a detector 18. In this embodiment, the detection path 17 that detects the filtrate with the detector 18 is a collecting pipe 15, and the detector 18 is provided at one end of the collecting pipe 15. The detector 18 can detect the interior of the collecting pipe 15 linearly and longitudinally toward the other end, and detects the interface between the filtrate of a predetermined turbidity and the clear filtrate discharged from each filtration chamber 9 to the collecting pipe 15, and the distance to the detector 18.

[0023] The detector 18 transmits an irradiation wave into the collecting pipe 15, and converts the propagation time from when the irradiation wave is reflected by filtrate with a predetermined turbidity until it receives the reflected wave into distance, and outputs the converted value. In this embodiment, a laser level meter is used for the detector 18, and a laser beam is emitted into the collecting pipe 15 from the detector 18 fixed to the rear section, which is upstream of the filtrate flowing down the collecting pipe 15, toward the front section.

[0024] If the filter cloth 6 is not damaged, the inside of the collecting pipe 15 is filled with clear filtrate, the laser light is irradiated up to the other end of the collecting pipe 15, and the light reflected by the discharge pipe 16 is received by the detector 18. The detector 18 outputs a distance equal to or greater than the length of the row of filter plates 5.

[0025] If some of the filter cloths 6 are damaged and highly turbid filtrate containing suspended solids in the filtration chamber 9 is discharged into the collecting pipe 15, the laser light will be reflected by the highly turbid filtrate being discharged into the collecting pipe 15 from the connecting part 19 with the filtrate passage 10. The reflected light is received by the detecting device 18 and the distance to the discharge position of the highly turbid filtrate is output, so it is immediately determined that the filter cloth 6 in the filtration chamber 9 corresponding to the output distance is likely to be damaged.

[0026] It is desirable to adjust the output of the irradiation wave emitted from the detector 18 in advance according to the raw liquid to be separated into solid and liquid in the filter press 1 so that damage to the filter cloth 6 can be detected with high accuracy.

[0027] In the event of an abnormality such as when the detector 18 outputs a distance shorter than the length of the filter plate 5 row, an alarm is issued on the control panel, etc. hand Alternatively, the distance from the detector 18 to each of the connection parts 19 may be input in advance, and the corresponding filtration chamber 9 or filter cloth 6 may be output on an operation panel or the like, so that the discharge position of the highly turbid filtrate discharged from each filtrate passage 10 to the collecting pipe 15 can be detected.

[0028] In this embodiment, laser light is used as the irradiated wave, but any irradiated wave (ultrasound, microwave, etc.) that passes through a transparent substance and is reflected at the interface between a filtrate of a predetermined turbidity and a clear filtrate can be used in the detection device 18 of the present invention.

[0029] FIG. 5 is a schematic explanatory diagram of detection along a detection path according to another first embodiment. The filtrate discharged from the filtrate passage 10 into the collecting pipe 15 flows down inside the collecting pipe 15 towards the front frame 2. In particular, the filtrate discharged from the downstream filtration chamber 9 into the collecting pipe 15 is swept away by the filtrate flowing down inside the collecting pipe 15 from the upstream side, so it flows downstream immediately after being discharged from the connecting part 19 into the collecting pipe 15, and this may prevent it from being detected by the irradiation wave of the detection device 18, or an error may occur in the detection position. Therefore, it is desirable to irradiate the vicinity of the connecting part 19 between the filtrate passage 10 and the collecting pipe 15, as shown in (a).

[0030] 1(b) shows an embodiment in which a downflow prevention plate 20 is provided upstream of the connection 19 between the filtrate passage 10 and the collecting pipe 15. By providing a transparent downflow prevention plate 20, through which the irradiation wave passes, at each connection 19, the pressure from the filtrate flowing down from the upstream side is inhibited, and the filtrate discharged from the filtrate passage 10 to the collecting pipe 15 flows to near the bottom at that position. The irradiation wave from the detection device 18 passes through the clear filtrate and the transparent downflow prevention plate 20 and is reflected at the interface between the filtrate of a predetermined turbidity and the clear filtrate, enabling accurate detection. The downflow prevention plate 20 hangs down from above to an appropriate position depending on the irradiation position of the irradiation wave from the detection device 18.

[0031] 1(c) is an embodiment in which a flow-down guide pipe 21 is provided at the connection 19 between the filtrate passage 10 and the collecting pipe 15. In this embodiment, a small-diameter T-shaped pipe is connected to each connection 19 inside the collecting pipe 15, and the inside of the T-shaped pipe is irradiated with an irradiation wave from the detection device 18, making it possible to detect the filtrate concentration before it becomes diluted. Since the openings of the T-shaped pipe are aligned with the upstream and downstream of the collecting pipe 15, the filtrate in all of the vertically arranged flow-down guide pipes 21 can be detected with a single irradiation wave.

[0032] FIG. 6 is a schematic explanatory diagram of detection along a detection path according to another embodiment 2. A detection path 22 is formed so as to connect a portion of each filtrate passage 10... in the front-to-rear direction of the collecting pipe 15. As with the collecting pipe 15, an integrated detection path 22 is formed by closing the filter plate 5. A detection device 18 irradiates an irradiation wave from one end of the detection path 22 toward the other end inside the detection path 22. The detection path 22 has a smaller diameter than the collecting pipe 15 and is linear, and the end is configured in a bag shape, so that the filtrate in the detection path 22 does not flow toward the adjacent filtration chamber 9.

[0033] Filtrate detection is performed during the injection process, in which the raw liquid is injected into the filtration chamber 9, and during the squeezing process, in which the dehydrated cake in the filtration chamber is squeezed with a diaphragm or the like after the injection process. After the detection paths 17 and 22 are filled with water, the detector 18 emits an irradiation wave. Because the amount of filtrate decreases over time during the injection process and squeezing process, detection may be performed for a predetermined time from the start of each process. The interval at which the detector 18 emits the irradiation wave is set in advance. [Industrial Applicability]

[0034] The filter cloth breakage detection device for a filter press of this invention utilizes the reflection of an irradiated wave by suspended solids in the filtrate to perform accurate detection, and can identify the position of the filter cloth in the vertically arranged filtering chamber from which suspended solids are being discharged. Therefore, this invention is very useful as a filter cloth breakage detection device for multi-chamber filter presses for drinking water sludge, sewage sludge, industrial wastewater sludge, etc. [Explanation of symbols]

[0035] 1. Filter press 5 Filter plate 6 filter cloth 9 Filtration Chamber 10 Filtrate passage 14 Drain 15 ,15a collecting pipe 17,22 Detection path 18 Detection Device 19 Connection 20 Flow prevention plate 21 Downflow guide pipe

Claims

1. A filter press (1) in which a filtrate obtained by solid-liquid separation using a filter cloth (6) sandwiched between filter plates (5, 5) is discharged into a collecting pipe (15) through a filtrate passage (10) of each filter plate (5...), a linearly communicating detection path (17, 22) in which filtrates discharged from each filtration chamber (9...) are collected; a detection device (18) that transmits an irradiation wave from the upstream end of a detection path (17, 22) through which the filtrate flows down, the irradiation wave being reflected at the interface between the filtrate of a predetermined turbidity and the clear filtrate, and converts the propagation time until the reflected wave is received into a distance and outputs the converted distance; Equipped with A filter cloth damage detection device for a filter press.

2. The detection path (17) is a collecting pipe (15) formed by connecting the drain outlets (14) of the filter plates (5...) to each other along the arrangement direction by closing the filter plates (5), and a detection device (18) is provided at the upstream end where the filtrate flows down.

2. The filter cloth damage detection device for a filter press according to claim 1.

3. The detection path (17) is a collecting pipe (15a) arranged in parallel with each filter plate (5...), and a detection device (18) is provided at the upstream end where the filtrate flows down.

2. The filter cloth damage detection device for a filter press according to claim 1.

4. The detection path (22) is formed by connecting a part of the filtrate passage (10) of each filter plate (5...) by closing the filter plate (5).

2. The filter cloth damage detection device for a filter press according to claim 1.

5. An irradiation wave is irradiated near the connection (19) between the detection path (17) and the filtrate passage (10).

4. The filter cloth damage detection device for a filter press according to claim 2 or 3.

6. A flow-down prevention plate (20) through which the irradiation wave can pass is provided on the upstream side of the connection part (19) between the detection path (17) and the filtrate passage (10).

4. The filter cloth damage detection device for a filter press according to claim 2 or 3.

7. A flow-down guide pipe (21) made of a T-shaped pipe is provided at the connection (19) between the detection path (17) and the filtrate passage (10), and the opening of the T-shaped pipe is aligned with the upstream and downstream of the collecting pipe (15), and the irradiation wave of the detection device (18) is irradiated into the inside of the T-shaped pipe.

4. The filter cloth damage detection device for a filter press according to claim 2 or 3.

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