Running control device for filter fabric and belt filter

Abstract

To provide a running control device for a filter fabric, which can sense an abnormality of a running state of a filter fabric that cannot be sensed by a conventional meander sensing device.SOLUTION: A running control device for a filter fabric 13 in a belt filter comprises sensing means 20 for sensing that a length in a width direction of the filter fabric 13 in a running state becomes shorter than a length in a normal state thereof. The sensing means 20 are arranged laterally at one side or at both sides in the width direction of the filter fabric 13, which comprise contact members 21 that turn toward the width direction of the filter fabric 13 with a predetermined turning shaft as a fulcrum and sensors 22 for sensing the turning of the contact members 21. The contact members 21 are configured to contact side edges of the filter fabric 13 to incline in a normal range with the turning shaft as the fulcrum, when the filter fabric 13 is in the normal state.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a travel control device for a filter cloth in a belt filter. The present invention also relates to a belt filter equipped with a travel control device. [Background technology]

[0002] Conventionally, belt filters have been used for treating slurries (suspensions) in the chemical machinery field, such as chemical plants, paper mills, and food factories. Belt filters generally rotate a dehydration drum with an endless filter cloth stretched on the outer periphery in a tank in which slurry is stored, filter the slurry in the tank with the filter cloth, and separate solids and liquids from the slurry in the tank by peeling off the dehydrated cake formed on the surface of the filter cloth from the filter cloth (Patent Document 1). Such belt filters can be used for solid-liquid separation treatment, such as treatment of wastewater generated in industrial processes.

[0003] Also, devices for detecting the meandering state of the filter cloth have been known for some time. That is, in a belt filter, the filter cloth stretched on the outer peripheral surface of the dehydration drum is rotated in the circumferential direction, and when the filter cloth is run for a long time, the center of the filter cloth may gradually become meandering toward one side in the axial direction of the dehydration drum. If the meandering state of the filter cloth is left as it is, in the worst case, the filter cloth may fall off the dehydration drum, so it is necessary to monitor the running state of the filter cloth and return the filter cloth to the normal position (the center of the drum) when meandering occurs. Therefore, for example, in the meandering detection device described in Patent Document 2, a lever that returns vertically by its own weight is arranged on either the left or right side of the width direction of the filter cloth, and a configuration is adopted in which the lever detects that the filter cloth has meandered and become biased to either the left or right side. In the meandering detection device of Patent Document 2, when the filter cloth becomes meandering, the filter cloth rotates the lever, so that the filter cloth is adjusted to return to the normal position according to the rotation angle of the lever. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Publication No. 59-180713 [Patent Document 2] Japanese Patent Application Publication No. 62-275598 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the meandering detection device of Patent Document 2 has a problem that, since the lever that returns to a vertical position by its own weight is arranged only on one side of the width of the filter cloth, for example, the filter cloth is twisted or bent during its travel, and the width of the filter cloth becomes shorter than the normal state. Specifically, this meandering detection device can detect such an abnormality in the filter cloth by changing the angle of the lever that slides against the side edge of the filter cloth when the filter cloth is traveling biased to the left or right while the width of the filter cloth is properly maintained (meandering state). However, for example, when the filter cloth is twisted, bent, or wavy, and both or one of the left and right side edges of the filter cloth are moved toward the center in the width direction and the width of the filter cloth is shortened, the lever arranged on only one side of the filter cloth cannot accurately determine whether the filter cloth is traveling biased to the left or right, or whether the width of the filter cloth is shorter than the normal state due to twisting or bending during its travel. In particular, the meandering detection device of Patent Document 2 cannot detect an abnormality occurring in the filter cloth, such as the length in the width direction during travel becoming shorter than normal.

[0006] SUMMARY OF THE PRESENT DISCLOSURE ... Therefore, a main object of the present invention is to make it possible to detect abnormalities in the running state of a filter cloth that could not be detected by conventional meandering detection devices. [Means for solving the problem]

[0007] The inventors of the present invention have intensively studied means for solving the problems of the conventional inventions described above, and have found that, for example, by arranging a contact member that returns to a substantially vertical position under its own weight in contact with the width-direction side edge of a normally running filter cloth, it becomes possible to detect when the width-direction length of the filter cloth during running becomes shorter than normal. Based on the above findings, the inventors have come to the realization that it becomes possible to detect abnormalities in the running state of the filter cloth that could not be detected by the conventional inventions, and have completed the present invention. Specifically, the present invention has the following configuration.

[0008] The first aspect of the present invention relates to a device for controlling the running state of a filter cloth provided in a belt filter. The running control device according to the present invention is provided with a detection means for detecting that the widthwise length of the filter cloth becomes shorter than the normal state when the filter cloth is running. The "widthwise length of the filter cloth" here means the linear distance from one side edge to the other side edge of the filter cloth during running. Therefore, when the filter cloth is twisted, bent, wavy, or the like, the "widthwise length of the filter cloth" becomes shorter by that amount. In the conventional meandering detection device, it was not possible to detect that both or one of the left and right side edges of the filter cloth are moved toward the center in the width direction and the widthwise length (linear distance) of the filter cloth is shortened. In the present invention, by providing a detection means for detecting such an abnormality of the filter cloth, it becomes possible to detect an abnormality in the running state of the filter cloth that could not be detected by the conventional meandering detection device.

[0009] In the travel control device according to the present invention, the detection means preferably includes a contact member and a sensor. The contact member is arranged on one or both widthwise sides of the filter cloth, and rotates in the width direction of the filter cloth around a predetermined rotation axis. In particular, the contact members are preferably arranged on both widthwise sides of the filter cloth. The sensor detects the rotation of the contact member. Here, the contact member is configured to contact the side edge of the filter cloth when the filter cloth is in a normal state and tilt within a normal range around the rotation axis. The sensor also includes a first sensor. This first sensor detects that the side edge of the filter cloth in contact with the contact member is displaced toward the center in the width direction and the tilt angle of the contact member deviates from the normal range. For example, when the contact member is no longer in contact with the side edge of the filter cloth, the state of such a contact member is detected by the first sensor. Thus, in the present invention, the filter cloth is brought into contact with the contact member in advance when the travel state of the filter cloth is normal, and when the filter cloth is separated from the contact member when an abnormality occurs, the state of the contact member is detected by the first sensor. As a result, the present invention makes it possible to detect abnormalities in the running condition of the filter cloth that could not be detected by conventional meandering detection devices, such as a shortening of the width direction of the filter cloth while it is running.

[0010] In the travel control device according to the present invention, the contact member and the first sensor are preferably disposed on both sides in the width direction of the filter cloth. In the present invention, the contact member and the first sensor may be disposed on only one side in the width direction of the filter cloth, but by disposing them on both sides in the width direction of the filter cloth, abnormalities in the travel state of the filter cloth can be detected more accurately.

[0011] In the travel control device according to the present invention, it is preferable that the first sensor is capable of detecting a state in which the contact member has become free from the side edge of the filter cloth, thereby making it possible to more accurately detect, for example, a shortening of the width of the filter cloth during travel.

[0012] In the travel control device according to the present invention, it is preferable that the sensor further includes a second sensor. The second sensor detects that the side edge of the filter cloth in contact with the contact member is displaced toward the outside in the width direction, and the inclination angle of the contact member deviates from the normal range. In this way, by providing a second sensor that detects that the side edge of the filter cloth is displaced toward the outside in the width direction, it is possible to detect that the filter cloth is in a meandering state, as with a conventional meandering detection device. In addition, by providing a first sensor and a second sensor on both sides of the filter cloth in the width direction, it is possible to identify whether the filter cloth is meandering to the left or right, whether one side of the side edge of the filter cloth is twisted or bent, or whether both sides of the side edge of the filter cloth are twisted or bent, depending on the combination of detection information from each sensor.

[0013] The travel control device according to the present invention preferably further includes an adjustment means. When the first sensor detects that the inclination angle of the contact member deviates from the normal range, the adjustment means displaces the side edge of the filter cloth in contact with the contact member (including the "side edge of the filter cloth that was in contact with the contact member") toward the outside in the width direction. In other words, the fact that the first sensor detects the contact member means that the side edge of the filter cloth on the first sensor side is warped or bent, shortening the width direction length of the filter cloth during travel, or the filter cloth is meandering away from the first sensor. Therefore, in this case, the travel state of the filter cloth can be returned to normal by displacing the side edge of the filter cloth in contact with the contact member toward the outside in the width direction using the adjustment means.

[0014] In the travel control device according to the present invention, the adjustment means includes one or more rollers that are configured to contact the side edge portions of the filter cloth and pull the side edge portions toward the outside in the width direction, thereby enabling the filter cloth to return to a normal travel state while maintaining continuous travel of the filter cloth.

[0015] A second aspect of the present invention relates to a belt filter having the travel control device according to the first aspect. That is, the travel control device according to the present invention can be implemented alone or incorporated in a belt filter. Effect of the Invention

[0016] According to the present invention, it is possible to detect abnormalities in the running state of the filter cloth, which could not be detected by conventional meandering detection devices. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a side view showing an example of the configuration of a belt filter. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of the configuration of the detection means, showing the case where the running state of the filter cloth is normal. [Diagram 3] FIG. 3 is an enlarged view showing an example of the configuration of the detection means. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the configuration of the detection means, and shows a case where the filter cloth meanders and shifts to the left. [Diagram 5] FIG. 5 is a cross-sectional view showing an example of the configuration of the detection means, showing the case where the filter cloth meanders further to the left. [Figure 6] FIG. 6 is a cross-sectional view showing an example of the configuration of the detection means, and shows a case where the right side edge of the filter cloth is shifted toward the center. [Figure 7] FIG. 7 is a cross-sectional view showing an example of the configuration of the detection means, in which both the left and right side edges of the filter cloth are shifted toward the center. [Figure 8] FIG. 8 is an enlarged view showing a configuration example of the adjustment means. [Figure 9] FIG. 9 is a plan view showing an example of the configuration of the adjustment means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and includes appropriate modifications of the embodiments described below within the scope obvious to those skilled in the art.

[0019] In each figure, the X-axis, Y-axis, and Z-axis are indicated by arrows in an orthogonal coordinate system. The X-axis corresponds to the longitudinal direction (travel direction) of the filter cloth, the Y-axis corresponds to the width direction of the filter cloth, and the Z-axis indicates the thickness direction (height direction) of the filter cloth.

[0020] Fig. 1 shows a belt filter 1 according to an embodiment of the present invention. As shown in Fig. 1, the belt filter 1 according to this embodiment includes a tank 11, a dehydration drum 12, a filter cloth 13, a vent pulley 14, a tension pulley 15, a chute 16, and a cleaning device 17. The belt filter 1 further includes a travel control device 2 for adjusting the travel state of the filter cloth 13. The travel control device 2 includes a detection means 20 for detecting an abnormality in the travel state of the filter cloth 13, and an adjustment means 30 for returning the travel state of the filter cloth 13 to normal when an abnormality in the filter cloth 13 is detected.

[0021] The tank 11 is a container for storing the slurry SL (suspension) to be treated by the belt filter 1. There is no particular limit to the type of slurry SL treated by the belt filter 1, but the belt filter 1 is suitable for treating wastewater generated in industrial processes, such as chemical plants, paper mills, and food factories. Although not shown in the figure, the tank 11 is connected to a supply nozzle for supplying untreated slurry SL into the tank 11 and a discharge nozzle for discharging the overflow of the slurry SL to the outside of the tank 11.

[0022] The dehydration drum 12 is a vacuum type drum, and an endless filter cloth 13 is hung on its outer circumferential surface. The dehydration drum 12 and the filter cloth 13 are arranged so as to be partially immersed in the slurry SL in the tank 11. When the dehydration drum 12 rotates, the filter cloth 13 travels, and the entire filter cloth 13 passes through the slurry SL in sequence. The dehydration drum 12 mainly sucks the filter cloth 13 on the surface that contacts the filter cloth 13. Therefore, the slurry SL in the tank 11 and the slurry SL that has soaked into the filter cloth 13 pass through the filter cloth 13 and are sucked into the dehydration drum 12. As a result, the slurry SL is filtered by the filter cloth 13. That is, the liquid contained in the slurry SL passes through the filter cloth 13 and is collected in the dehydration drum 12, while the solids in the slurry SL remain on the filter cloth 13 while adhering to the filter cloth 13, and become a dehydrated cake DC. Although not shown, the dehydration drum 12 is connected to a vacuum pump for creating a negative pressure inside the dehydration drum 12, a filtrate pump for draining the liquid (filtrate) collected in the dehydration drum 12, and a filtrate tank for storing this liquid. Alternatively, the dehydration drum 12 may be configured to have a vacuum area formed by covering the periphery of the dehydration drum 12 with a hood, and the filter cloth 13 and slurry SL may be sucked in this vacuum area (a so-called vacuum dehydration drum).

[0023] As described above, the filter cloth 13 is an endless filtration belt that is suspended around the dehydration drum 12. The filter cloth 13 may be any material that can filter the liquid constituting the slurry SL and collect solids on its surface, and the material, mesh size, thickness, etc. may be adjusted according to the type of the slurry SL. Furthermore, the longitudinal length and width length of the filter cloth 13 may be appropriately adjusted according to the application of the belt filter 1.

[0024] The vent pulley 14 is a pulley for running a portion of the filter cloth 13 pulled out from the dewatering drum 12 (i.e., a portion not in contact with the outer circumferential surface of the dewatering drum 12), and is arranged particularly for the purpose of changing the traveling direction of the filter cloth 13. In the example shown in Fig. 1, two vent pulleys 14 are arranged on the traveling path of the filter cloth 13. In Fig. 1, the vent pulley 14 that the filter cloth 13 passes first after leaving the dewatering drum 12 is designated as the first vent pulley 14(a), and the vent pulley 14 that the filter cloth 13 passes next is designated as the second vent pulley 14(b).

[0025] The tension pulley 15 is a pulley for running a part of the filter cloth 13 pulled out from the dewatering drum 12, like the vent pulley 14, but is configured so that the tension applied to the running filter cloth 13 can be adjusted by moving its position with an actuator. This ensures that a constant tension is always applied to the filter cloth 13 running by the dewatering drum 12, the vent pulley 14, and the tension pulley 15.

[0026] The chute 16 is a waste path connected to a waste port for discharging the dehydrated cake DC attached to the filter cloth 13. In the embodiment shown in FIG. 1, when the filter cloth 13 reaches the first vent pulley 14(a) and its traveling direction is bent, the dehydrated cake DC is peeled off from the surface of the filter cloth 13 and falls as it is. The chute 16 is provided at the destination where the dehydrated cake DC falls. Although not shown, a peeling means (brush, blade, etc.) for the dehydrated cake DC may be provided near the opposite side of the first vent pulley 14(a) sandwiching the filter cloth 13, to forcibly peel off the dehydrated cake DC attached to the surface of the filter cloth 13.

[0027] The cleaning device 17 is a device for cleaning the filter cloth 13 after the dewatered cake DC is peeled off. In the embodiment shown in FIG. 1, the cleaning device 17 is provided with a pair of roller brushes arranged on both the front side and the back side of the filter cloth 13, and these roller brushes are arranged between the first vent pulley 14(a) and the second vent pulley 14(b). The cleaning device 17 may be provided with a sprayer for spraying a cleaning liquid onto the filter cloth 13 in addition to or instead of the roller brushes. In this way, the filter cloth 13 cleaned by the cleaning device 17 reaches the outer circumferential surface of the dewatering drum 12 again, and is immersed in the slurry SL in the tank 11 as the dewatering drum 12 rotates. In this way, the filter cloth 13 is continuously run, so that the slurry SL in the tank 11 can be continuously treated.

[0028] The travel control device 2 has a function of monitoring the travel state of the filter cloth 13 and adjusting the filter cloth 13 to return it to normal when an abnormality occurs. Specifically, in this embodiment, the travel control device 2 is disposed in a section from when the filter cloth 13 leaves the outer circumferential surface of the dehydration drum 12 to when it reaches the first vent pulley 14(a). This section is immediately after the filter cloth 13 leaves the dehydration drum 12 and dehydrated cakes DC are accumulated on the filter cloth 13, so that abnormalities such as meandering, twisting, and bending are likely to occur in the filter cloth 13. For this reason, it is preferable to dispose the travel control device 2 in the section between the dehydration drum 12 and the first vent pulley 14(a).

[0029] 2 and 3 show the detection means 20 of the driving control device 2 according to this embodiment. As shown in FIG. 2, in this embodiment, the detection means 20 are arranged on both sides of the filter cloth 13 in the width direction. The one arranged on the left side of the filter cloth 13 is referred to as the left sensor device 20(L), and the one arranged on the right side of the filter cloth 13 is referred to as the right sensor device 20(R). Note that FIG. 3 shows an enlarged detailed configuration of the left sensor device 20(L), but the right sensor device 20(R) has the same configuration. As shown in FIG. 2 and FIG. 3, the left and right sensor devices 20(L,R) mainly include a contact member 21, a sensor 22, and a housing 23, respectively.

[0030] The contact member 21 is a member that contacts the side edge of the filter cloth 13 during travel. The contact member 21 includes a rotating shaft 21a, a vertical bar 21b, and a horizontal bar 21c. The vertical bar 21b and the horizontal bar 21c are each a linear rod-like member, and are joined together at the rotating shaft 21a as an intersection. In the illustrated example, the vertical bar 21b and the horizontal bar 21c are joined so as to be almost perpendicular to each other, and the member formed by these integrated members is substantially T-shaped. In reality, the vertical bar 21b of the contact member 21 directly contacts the side edge of the filter cloth 13. The angle between the vertical bar 21b and the horizontal bar 21c (the acute angle side between the horizontal bar 21c and the vertical bar 21b on the opposite side of the filter cloth 13 with the vertical bar 21b sandwiched in the Y direction) is most preferably a right angle (90 degrees), but may be within a range of 70 to 90 degrees, and may be 80 to 90 degrees.

[0031] The substantially T-shaped member in which the vertical bar 21b and the horizontal bar 21c are integrated rotates in the width direction (Y-axis direction) of the filter cloth 13 with the rotation shaft 21a as a fulcrum. This T-shaped member can swing with the rotation shaft 21a as a fulcrum, but when no external pressure is applied to the vertical bar 21b, it tries to return to its natural state by its own weight. In the natural state, the vertical bar 21b extends in a vertical direction relative to the rotation shaft 21a, and the horizontal bar 21c extends in a horizontal direction relative to the rotation shaft 21a. On the other hand, when the vertical bar 21b contacts the side edge of the filter cloth 13, the vertical bar 21b receives pressure from the filter cloth 13 and rotates with the rotation shaft 21a as a fulcrum. The horizontal bar 21c also rotates along with the vertical bar 21b. Depending on the weight balance of the T-shaped member, the vertical bar 21b may not be completely vertical, and the horizontal bar 21c may not be completely horizontal. In the natural state of this T-shaped member, it is preferable that the vertical bar 21b is approximately vertical (90 degrees ±10 degrees with respect to the horizontal plane) and the horizontal bar 21c is approximately horizontal (0 degrees ±10 degrees with respect to the horizontal plane). In addition, in the natural state where the vertical bar 21b is not subjected to external pressure, the horizontal bar 21c may be restricted by contact with an external element such as the housing 23, so that the vertical bar 21b may be maintained approximately vertical and the horizontal bar 21c may be maintained approximately horizontal.

[0032] As described above, in consideration of the vertical bar 21b being approximately vertical and the horizontal bar 21c being approximately horizontal in the natural state, it is preferable that the vertical bar 21b and the horizontal bar 21c are joined in an approximately T-shape as described above. However, for example, one end of the vertical bar 21b and one end of the horizontal bar 21c may be joined to form an approximately L-shaped member. In addition, the vertical bar 21b and the horizontal bar 21c do not necessarily have to be straight members, and may be bent or curved within a range that does not impair the function of the detection means 20. In addition, the vertical bar 21b and the horizontal bar 21c do not necessarily have to be rod-shaped (cylindrical, polygonal prism-shaped), and may be planar members.

[0033] 2 and 3 show the state of the contact member 21 when the filter cloth 13 is running normally. As shown in each figure, the contact member 21 is installed so as to come into contact with the side edge of the filter cloth 13 running normally and to be inclined at a predetermined angle with the rotation shaft 21a as a fulcrum. In other words, when the filter cloth 13 is running normally, the vertical bar 21b of the contact member 21 receives pressure from the filter cloth 13. In FIG. 3, the inclination angle when the vertical bar 21b moves from its natural state to a state in which it is in contact with the side edge of the normal filter cloth 13 is indicated by the symbol θ. 1 That is, the vertical bar 21b in contact with the side edge of the normal filter cloth 13 is approximately vertical when not receiving external pressure, but when in contact with the filter cloth 13 that is moving normally, the vertical bar 21b is at an angle θ 1 The vertical bar 21b is inclined at an inclination angle θ 1 Theoretically, the inclination angle θ can be selected from the range of 1 to 89 degrees, but in practice, it is preferably 1 to 45 degrees, and more preferably 5 to 30 degrees. 1 is about 10 to 15 degrees. It is obvious that the horizontal bars 21c will also be inclined in accordance with such an inclination of the vertical bars 21b.

[0034] On the other hand, when the side edge of the filter cloth 13 is displaced in a direction away from the vertical bar 21b (toward the inside in the width direction), the contact member 21 tries to return to its natural state by its own weight. When the side edge of the filter cloth 13 is completely separated from the vertical bar 21b, the vertical bar 21b becomes substantially vertical, and the horizontal bar 21c becomes substantially horizontal. In the embodiment shown in FIG. 3, when the side edge of the filter cloth 13 is completely separated from the vertical bar 21b, the horizontal bar 21c comes into contact with the bottom surface of the sensor storage case 23b of the housing 23 and does not rotate any further. Therefore, the angle between the vertical bar 21b and the horizontal bar 21c is maintained. It is also possible to prevent the vertical bar 21b and the horizontal bar 21c from coming into contact with anything when the side edge of the filter cloth 13 is completely separated from the vertical bar 21b. On the other hand, when the side edge of the filter cloth 13 is displaced in a direction approaching the vertical bar 21b (toward the outside in the width direction), the inclination angle of the vertical bar 21b and the horizontal bar 21c of the contact member 21 becomes smaller than the normal inclination angle θ 1 Thus, the normal inclination angle θ 1 On the other hand, when the inclination angle of the contact member 21 becomes small or large, it can be said that there is a possibility that some abnormality has occurred in the running state of the filter cloth 13 in either case.

[0035] The sensor 22 detects the rotation of the contact member 21. In this embodiment, more specifically, the sensor 22 is configured to detect the rotation of the horizontal bar 21c of the contact member 21. That is, as shown in FIG. 3, the sensor 22 is installed on the rotation path of the horizontal bar 21c and is configured to detect that the inclination angle of the horizontal bar 21c deviates from a certain normal range. In this embodiment, the sensor 22 includes a total of four sensors, a first sensor 22a, a second sensor 22b, a third sensor 22c, and a fourth sensor 22d. A proximity sensor can be adopted as each of the sensors 22a to 22d. The proximity sensor is a sensor that detects the approach of a detection object in a non-contact manner. That is, when the proximity sensor detects the approach of the horizontal bar 21c, it outputs a detection signal. The type of the proximity sensor is not particularly limited, but for example, a general optical, magnetic, or capacitive sensor may be used.

[0036] As shown in Fig. 3, the sensor 22 has a non-detection area in which the horizontal bar 21c is not detected by the sensors 22a to 22d. In Fig. 3, this non-detection area is indicated by a dotted frame. The range of this non-detection area corresponds to the normal range of the inclination angle of the contact member 21 (specifically, the horizontal bar 21c). In other words, when the inclination angle of the contact member 21 is within the normal range, the horizontal bar 21c belongs to the non-detection area of ​​the sensor 22.

[0037] In addition, sensors 22a to 22d are located in front of and behind the non-detection area. Specifically, when the side edge of the filter cloth 13 is displaced in a direction away from the contact member 21 (toward the inside in the width direction) and the filter cloth 13 is completely separated from the contact member 21, the horizontal bar 21c of the contact member 21 deviates from this non-detection area and is detected by the first sensor 22a. In the example shown in Fig. 3, when the filter cloth 13 is completely separated from the contact member 21, the horizontal bar 21c becomes approximately horizontal and is detected by the first sensor 22a. For the sake of convenience, the angle at which the horizontal bar 21c of the contact member 21 is detected by the first sensor 22a is set as the initial angle (0 degrees).

[0038] On the other hand, when the side edge of the filter cloth 13 is displaced in a direction approaching the contact member 21 (toward the outside in the width direction), the horizontal bar 21c of the contact member 21 gradually deviates from the non-detection area and is detected by the second sensor 22b. Furthermore, when the displacement of the side edge of the filter cloth 13 progresses further, the horizontal bar 21c of the contact member 21 is detected in the order of the third sensor 22c and the fourth sensor 22d. In this way, when the side edge of the filter cloth 13 is displaced in a direction approaching the contact member 21, the detection of the horizontal bar 21c is performed stepwise in the order of the second sensor 22b, the third sensor 22c, and the fourth sensor 22d. The intervals between these second sensor 22b, the third sensor 22c, and the fourth sensor 22d may be, for example, 3 to 20 degrees or 5 to 15 degrees based on the inclination angle of the horizontal bar 21c.

[0039] In the configuration of this embodiment, the area between the first sensor 22a and the second sensor 22b is a non-detection area. As described above, if the angle at which the horizontal bar 21c is detected by the first sensor 22a is the initial angle (0 degrees), the angle at which the horizontal bar 21c is detected by the second sensor 22b is preferably set to, for example, a range of 15 to 45 degrees, and is preferably set to 18 to 40 degrees or 20 to 35 degrees. In other words, the non-detection area of ​​the sensor 22 is a range of 15 to 45 degrees and is a range that is not detected by the first sensor 22a and the second sensor 22b. The setting of this non-detection area can be appropriately adjusted depending on the use of the belt filter 1, etc.

[0040] The housing 23 is an element for supporting the contact member 21 and the sensor 22. In this embodiment, the housing 23 includes a support base 23a fixed on the ground surface, a sensor storage case 23b for storing the sensor 22, a transparent cover 23c forming at least one surface of the sensor storage case 23b, a sensor support 23d for supporting the sensors 22a to 22d in the sensor storage case 23b, and a bar support 23e for rotatably fixing the contact member 21 to the sensor storage case 23b. In this manner, it is preferable to store and protect the sensors 22a to 22d in the sensor storage case 23b. In addition, the horizontal bar 21c of the contact member 21 is inserted in the sensor storage case 23b, and the rotation of the horizontal bar 21c can be detected by the sensors 22a to 22d inside the sensor storage case 23b. In addition, the rotation shaft 21a of the contact member 21 is located outside the sensor storage case 23b, but is fixed to the bar support 23e also provided outside the sensor storage case 23b. As described above, when the filter cloth 13 is completely separated from the contact member 21, the horizontal bar 21c of the contact member 21 comes into contact with the bottom surface of the sensor storage case 23b and is restricted from rotating any further. Therefore, the first sensor 22a detects the horizontal bar 21c in contact with the bottom surface of the sensor storage case 23b. In addition, since at least one surface of the sensor storage case 23b is covered with a transparent cover 23c made of acrylic or glass, the movement of the horizontal bar 21c inside the sensor storage case 23b can be visually confirmed.

[0041] Next, referring to FIG. 2 and FIG. 4 to FIG. 7, the running state of the filter cloth 13 and the corresponding operation of the left sensor device 20(L) and the right sensor device 20(R) will be described. As described above, FIG. 2 shows a case where the running state of the filter cloth 13 is normal. In this state, the contact members 21 of the left sensor device 20(L) and the right sensor device 20(R) are in contact with the side edges of the filter cloth 13 and are inclined within the normal range. In FIG. 2, the center of the width of the filter cloth 13 is indicated by the symbol C. Also, the passing point through which the center C of the filter cloth 13 should pass when the filter cloth 13 is in a normal running state is indicated by the symbol O. Furthermore, the optimal width-direction length (straight-line distance) of the filter cloth 13 without twisting or bending during running is indicated by the symbol W. As shown in FIG. 2, it is ideal that the center C of the filter cloth 13 is located on the normal passing point O and the width-direction length of the filter cloth 13 is maintained at the optimal length W.

[0042] On the other hand, FIG. 4 shows a case where the filter cloth 13 meanders and is biased to the left. In this case, although the width direction length of the filter cloth 13 is maintained at the optimal length W, the entire filter cloth 13 is biased to the left, so that it can be said that there is an abnormality in the running state of the filter cloth 13. At this time, the left edge of the filter cloth 13 is displaced in a direction approaching the left sensor device 20(L), so that the inclination angle of the contact member 21 of the left sensor device 20(L) becomes larger than the normal range. As a result, in the left sensor device 20(L), the horizontal bar 21c of the contact member 21 is detected by the second sensor 22b. In addition, the right edge of the filter cloth 13 is separated from the contact member 21 of the right sensor device 20(R), so that the inclination angle of the contact member 21 of the right sensor device 20(R) becomes smaller than the normal range. As a result, in the right sensor device 20(R), the horizontal bar 21c of the contact member 21 is detected by the first sensor 22a. In such a case, it can be determined that the filter cloth 13 is meandering to the left side in the width direction while maintaining the optimal length W to some extent based on the detection signals of the left and right sensor devices 20 (L, R). In such a case, the adjustment means 30 is controlled based on this detection information, and the filter cloth 13 is moved to the right side in the width direction by the adjustment means 30, so that the running state of the filter cloth 13 can be returned to normal. Note that FIG. 4 shows a case where the horizontal bar 21c is detected by the second sensor 22b of the left sensor device 20 (L), but since the horizontal bar 21c is no longer detected after passing the second sensor 22b, the same control is executed when the horizontal bar 21c is detected by the third sensor 22c. Note that, although the case where the second sensor 22b and the third sensor 22c are provided has been described, a single sensor whose detection range is expanded to the range of the positions of both sensors may be used.

[0043] FIG. 5 shows a case where the filter cloth 13 is further leftwardly shifted than in FIG. 3. At this time, the left edge of the filter cloth 13 is largely displaced toward the left sensor device 20(L), so the inclination angle of the contact member 21 of the left sensor device 20(L) becomes large and significantly exceeds the normal range. As a result, in the left sensor device 20(L), the horizontal bar 21c of the contact member 21 is detected by the fourth sensor 22d. In the right sensor device 20(R), the horizontal bar 21c of the contact member 21 is detected by the first sensor 22a, which is the same as in FIG. 3. In such a case, it can be determined that the meandering width of the filter cloth 13 is critically large based on the detection signals of the left and right sensor devices 20(L,R). Therefore, when the horizontal bar 21c is detected by the fourth sensor 22d, it is preferable to stop the travel of the filter cloth 13 by the belt filter 1 and return the filter cloth 13 to the appropriate position. This makes it possible to prevent the worst case scenario of the filter cloth 13 falling off the dewatering drum 12.

[0044] In Figures 3 and 4, the operation of the left and right sensor devices 20 (L, R) has been explained using the example of the case where the filter cloth 13 is biased to the left side. However, when the filter cloth 13 is biased to the right side, the operation of the left and right sensor devices 20 (L, R) is simply reversed, and basically the same operation is performed.

[0045] FIG. 6 shows a case where the right edge of the filter cloth 13 is displaced toward the center in the width direction. That is, the width direction length W' (straight line distance) of the filter cloth 13 during travel is shorter than the optimal length W. In this case, even if the center C of the filter cloth 13 is located on the normal passing point O as shown in FIG. 6, the right edge of the filter cloth 13 is twisted or bent, so that it can be said that there is an abnormality in the travel state of the filter cloth 13. At this time, since the right edge of the filter cloth 13 is separated from the contact member 21 of the right sensor device 20(R), the inclination angle of the contact member 21 of the right sensor device 20(R) is less than the normal range. As a result, in the right sensor device 20(R), the horizontal bar 21c of the contact member 21 is detected by the first sensor 22a. On the other hand, there is no particular abnormality in the left edge of the filter cloth 13 when viewed locally. Therefore, the contact member 21 of the left sensor device 20(L) and the left edge of the filter cloth 13 remain in moderate contact with each other. As a result, in the left sensor device 20(L), the horizontal bar 21c of the contact member 21 is in the non-detection area of ​​the sensor 22, and no particular detection signal is emitted. In such a case, based on the detection signals of the left and right sensor devices 20(L,R), it can be determined that an abnormality has occurred on the right edge side of the filter cloth 13, and that the width direction length W' of the filter cloth 13 during its travel is shorter than the optimal length W. Therefore, the adjustment means 30 can be controlled based on this detection information, and the right edge side of the filter cloth 13 can be pulled outward in the width direction by the adjustment means 30, thereby returning the travel state of the filter cloth 13 to normal.

[0046] Also, FIG. 7 shows a case where both the left edge and the right edge of the filter cloth 13 are displaced toward the center in the width direction. That is, the width direction length W' (straight line distance) of the filter cloth 13 during travel is shorter than the optimal length W. In this case, even if the center C of the filter cloth 13 is located on the normal passing point O as shown in FIG. 7, the filter cloth 13 is generally twisted or bent, so that it can be said that there is an abnormality in the travel state of the filter cloth 13. At this time, since the left edge of the filter cloth 13 is separated from the contact member 21 of the left sensor device 20(L), the inclination angle of the contact member 21 of the left sensor device 20(L) is less than the normal range. As a result, in the left sensor device 20(L), the horizontal bar 21c of the contact member 21 is detected by the first sensor 22a. Similarly, since the right edge of the filter cloth 13 is also separated from the contact member 21 of the right sensor device 20(R), the inclination angle of the contact member 21 of the right sensor device 20(R) is less than the normal range. As a result, the horizontal bar 21c of the contact member 21 is also detected by the first sensor 22a of the right sensor device 20(R). In such a case, it can be determined based on the detection signals of the left and right sensor devices 20(L,R) that an abnormality has occurred on the left and right edges of the filter cloth 13, and that the width-direction length W' of the filter cloth 13 during its travel is shorter than the optimum length W overall. Therefore, the adjustment means 30 can be controlled based on this detection information, and the adjustment means 30 can be used to pull both the left and right edges of the filter cloth 13 outward in the width direction, thereby returning the travel state of the filter cloth 13 to normal.

[0047] Next, a specific example of the adjustment means 30 will be described with reference to Fig. 8 and Fig. 9. In this embodiment, the adjustment means 30 are arranged on both the left and right sides in the width direction of the filter cloth 13 as shown in Fig. 9, and each of them performs an adjustment operation to return the running state of the filter cloth 13 to normal based on the detection information from the detection means 20 described above.

[0048] 8, the left and right adjustment means 30 each have a front roller 31 and a back roller 32. The front roller 31 is located on the front side of the filter cloth 13, and the back roller 32 is located on the back side of the filter cloth 13. When adjusting the running state of the filter cloth 13, the front roller 31 and the back roller 32 tightly pinch the portions of the filter cloth 13 near the side edges.

[0049] Each adjustment means 30 has a roller support base 33 fixed to the ground surface, a front roller support tool 34 fixed to the roller support base 33 and rotatably supporting the front roller 31, and a back roller support tool 35 rotatably supporting the back roller 32. However, the back roller support tool 35 is not directly fixed to the roller support base 33, and a lifting mechanism 36 is interposed between the roller support base 33 and the back roller support tool 35. The lifting mechanism 36 is, for example, a link mechanism in which a rotating shaft 36a is fixed to a part of the roller support base 33, and one end of the link mechanism is connected to an end of the back roller support tool 35. Therefore, when the cylinder rod connected to the rotating shaft 36b of the lifting mechanism 36 is moved in the Z direction and rotated around the rotating shaft 36a, the back roller support tool 35 connected to the end of the link mechanism 36 is lifted up and down together with the back roller 32. When the back roller 32 is lifted, the filter cloth 13 is tightly sandwiched between the front roller 31 and the back roller 32. Since the filter cloth 13 runs in its longitudinal direction (X-axis direction), when the front roller 31 and the back roller 32 pinch the filter cloth 13, frictional force is generated between them, and the rollers 31, 32 start rotating as the filter cloth 13 runs. On the other hand, when the back roller 32 is lowered, the filter cloth 13 is released from being pinched between the front roller 31 and the back roller 32. In this case, the back roller 32 in particular is no longer in contact with the filter cloth 13, and the frictional force between the rollers 31, 32 and the filter cloth 13 becomes zero or weak, so that the rotation of the rollers 31, 32 stops or slows down.

[0050] 9, in the left and right adjustment means 30 (L, R), the front roller 31 and the back roller 32 are supported by the front roller support 34 and the back roller support 35 described above so that their respective rotation axes are inclined obliquely with respect to the width direction (Y-axis direction) of the filter cloth 13. The inclination angle θ of each roller 31, 32 with respect to the width direction of the filter cloth 13 is 2The angle may be, for example, 5 to 30 degrees, and is more preferably 10 to 20 degrees. In addition, the rotation axis of each roller 31, 32 is inclined so that the feed direction of the filter cloth 13 (the direction indicated by the black arrow in FIG. 9) faces the outside of the width direction of the filter cloth 13. Therefore, when the filter cloth 13 travels in a certain direction with the side edge portion of the filter cloth 13 tightly sandwiched between the rollers 31, 32 from the front and back sides, a force is generated that pulls and guides the side edge portion of the filter cloth 13 toward the outside in the width direction as the rollers 31, 32 rotate. For example, if the filter cloth 13 is sandwiched only by the rollers 31, 32 of the left adjustment means 30(L), the filter cloth 13 will be pulled to the left, and conversely, if the filter cloth 13 is sandwiched only by the rollers 31, 32 of the right adjustment means 30(R), the filter cloth 13 will be pulled to the right. Furthermore, when the filter cloth 13 is simultaneously sandwiched between the rollers 31, 32 of both the left and right adjustment means 30 (L, R), the filter cloth 13 is pulled to both the left and right sides.

[0051] In this way, the left and right adjustment means 30 are independently controlled according to the abnormal state of the filter cloth 13 detected by the detection means 20, so that the filter cloth 13 can be automatically returned to a normal state. Specifically, when the entire filter cloth 13 is meandering to the left, the entire filter cloth 13 can be guided to the right by the right adjustment means 30(R). Conversely, when the entire filter cloth 13 is meandering to the right, the entire filter cloth 13 can be guided to the left by the left adjustment means 30(L). Also, when the left edge of the filter cloth 13 is twisted or bent and the width of the filter cloth 13 is reduced, the left edge of the filter cloth 13 can be pulled outward by the left adjustment means 30(L). Conversely, when the right edge of the filter cloth 13 is twisted or bent and the width of the filter cloth 13 is reduced, the right edge of the filter cloth 13 can be pulled outward by the right adjustment means 30(R). Furthermore, when the filter cloth 13 is twisted or bent on both the left and right side edges, the entire filter cloth 13 can be pulled outward on the left and right sides by the left and right adjustment means 30 (L, R). This makes it possible to deal with any abnormality in the running state of the filter cloth 13 in this embodiment. Therefore, the belt filter 1 can be operated stably and continuously.

[0052] In the above, in order to express the contents of the present invention, the present specification has described the embodiments of the present invention with reference to the drawings. However, the present invention is not limited to the above-mentioned embodiments, and includes modifications and improvements that are obvious to a person skilled in the art based on the matters described in the present specification. [Explanation of symbols]

[0053] 1... Belt filter 2... Driving control device 11...Tank 12...Dehydration drum 13...Filter cloth 14...Vent pulley 15...Tension pulley 16...Chute 17... cleaning device 20... detection means 20(L)...Left sensor device 20(R)...Right sensor device 21... contact member 21a... rotating shaft 21b...Vertical bar 21c...Horizontal bar 22...sensor 22a...first sensor 22b...Second sensor 22c...Third sensor 22d...fourth sensor 23...housing 23a... Support stand 23b... Sensor storage case 23c: Transparent cover 23d: Sensor support 23e... Bar support 30... Adjustment means 31: Surface roller 32: Back roller 33... Roller support base 34... Surface roller support 35... Back roller support 36... Lifting mechanism 36a...rotating shaft 36b...rotating shaft SL: Slurry DC: Dewatered cake

Claims

1. A travel control device for a filter cloth in a belt filter, A detection means is provided for detecting when the length of the filter cloth in the width direction becomes shorter than the normal length while the filter cloth is traveling. Cruise control device.

2. The detection means is A contact member is arranged on one or both sides of the filter fabric in the width direction and rotates toward the width direction of the filter fabric around a predetermined rotation axis as a fulcrum; a sensor for detecting rotation of the contact member; The contact member is configured to contact a side edge of the filter cloth when the filter cloth is in a normal state and to tilt within a normal range with the rotation axis as a fulcrum, The sensor includes a first sensor that detects that a side edge of the filter cloth in contact with the contact member is displaced toward the center in the width direction and the inclination angle of the contact member deviates from the normal range. The cruise control device according to claim 1.

3. The contact member and the first sensor are disposed on both sides of the filter cloth in the width direction. The cruise control device according to claim 2.

4. The first sensor is capable of detecting a state in which the contact member has been separated from the side edge of the filter cloth and become free. The cruise control device according to claim 2.

5. The sensor further includes a second sensor that detects that the side edge of the filter cloth in contact with the contact member is displaced toward the outside in the width direction and the inclination angle of the contact member deviates from the normal range. The cruise control device according to claim 2.

6. The apparatus further includes an adjustment means for displacing a side edge of the filter cloth in contact with the contact member toward an outer side in the width direction when the first sensor detects that the inclination angle of the contact member deviates from the normal range. The cruise control device according to claim 2.

7. The adjustment means includes one or more rollers configured to contact the side edge portion of the filter fabric and pull the side edge portion toward the outside in the width direction. The cruise control device according to claim 6.

8. A belt filter comprising the drive control device according to any one of claims 1 to 7.

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