JP2016002516A - Sludge dehydration system, and control method of sludge dehydration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge dehydration system and a control method of the sludge dehydration system where a total use amount of wash water does not increase while keeping desired washing performance even when the travel speed of a filter cloth belt is changed.SOLUTION: A sludge dehydration system 10 includes an endless filter cloth belt 20 that travels on a circulation track and practices solid-liquid separation while conveying sludge, and a washing device 23 that washes the filter cloth belt 20 by discharging wash water from a nozzle 23a. The sludge dehydration system 10 further includes: a travel speed changing unit 68 that changes the travel speed of the filter cloth belt 20; a washing location displacing unit 70 that displaces a washing location W where the filter cloth belt 20 is washed by the washing device 23, in the longitudinal direction of the filter cloth belt 20 at a displacement speed corresponding to the travel speed of the filter cloth belt 20; and a discharge control unit 64 that practices on-off control of wash water discharge from the nozzle 23a according to the travel speed of the filter cloth belt 20.

Description

  The present invention relates to a sludge dewatering system that performs solid-liquid separation while conveying sludge with an endless filter cloth belt, and a control method therefor.

  2. Description of the Related Art Conventionally, a dehydration system that separates solid and liquid while conveying sludge such as sewage and industrial wastewater with an endless filter cloth belt that runs on a circular track has been used. In such a dewatering system, in order to prevent the circulating filter cloth belt from being clogged with sludge, the filter cloth belt is generally washed with high-pressure washing water.

  In such cleaning of the filter cloth belt, it is important in terms of environment and running cost to reduce the amount of water used. Thus, for example, in Patent Documents 1 and 2, in a belt press dewatering device that pressurizes and dewaters sludge between a pair of upper and lower filter cloth belts, the dirt on the filter cloth belt and the peeling state of the sludge are optically detected and detected. A configuration is disclosed in which the amount of cleaning water used is reduced by controlling on / off the discharge of cleaning water or controlling the amount (flow rate) of discharging water in accordance with the degree of contamination.

Japanese Patent Laid-Open No. 01-233098 Japanese Patent Laid-Open No. 62-179896

  When washing the sludge adhering to the filter cloth belt with washing water as described above, the washing water discharge pressure and the discharge rate (discharge flow rate) per unit time are set to constant conditions in order to maintain the washing performance. It is necessary to keep it.

  By the way, in the above sludge dewatering system, the traveling speed of the filter cloth belt may be changed depending on the properties of the sludge to be treated. In that case, in the above prior art, the degree of contamination of the filter cloth belt is detected, and the discharge of the cleaning water is controlled accordingly, so that the cleaning water is continuously discharged regardless of the traveling speed of the filter cloth belt. Or intermittent discharge. Therefore, for example, when the traveling speed of the filter cloth belt is set slower than the standard speed, the total amount of cleaning water used increases or cleaning leakage occurs.

  The present invention has been made in consideration of the above-mentioned conventional problems, and even when the traveling speed of the filter cloth belt is changed, the total amount of cleaning water used does not increase and the desired cleaning performance is maintained. An object of the present invention is to provide a sludge dewatering system and a control method for the sludge dewatering system.

  The sludge dewatering system according to the present invention includes an endless filter cloth belt that travels on a circular track and separates solid and liquid while conveying sludge, and a cleaning device that discharges cleaning water from a nozzle to clean the filter cloth belt. A sludge dewatering system comprising: a traveling speed changing means for changing a traveling speed of the filter cloth belt; and cleaning of the filter cloth belt by the cleaning device at a displacement speed corresponding to the traveling speed of the filter cloth belt. A washing position displacing means for displacing the position in a direction along the longitudinal direction of the filter cloth belt, and a discharge control means for controlling on / off the discharge of the washing water from the nozzle according to the traveling speed of the filter cloth belt. It is characterized by providing.

  According to such a configuration, even when the traveling speed of the filter cloth belt is changed, the discharge of the cleaning water is controlled on and off according to the traveling speed of the filter cloth belt while the cleaning position of the nozzle is displaced by the cleaning position displacing means. can do. Thereby, the amount of cleaning water used for cleaning in a desired cleaning range can be made constant by turning on and off the discharge of cleaning water while appropriately displacing the cleaning position by the nozzle. Therefore, even when the traveling speed of the filter cloth belt is changed, it is possible to maintain the total amount of cleaning water used while maintaining the cleaning ability of the cleaning water discharged from the nozzles.

  The cleaning device is set so that the discharge pressure and the discharge flow rate of the cleaning water from the nozzle are always constant, and the cleaning position displacing means includes the traveling speed of the filter cloth belt set by the traveling speed changing means and the The displacement speed of the cleaning position is controlled so that the relative speed between the displacement speed of the cleaning position is always constant, and the discharge control means discharges the cleaning water required for cleaning the predetermined area of the filter cloth belt. The discharge of the washing water may be controlled on and off so that the on time is always constant. If it does so, the usage-amount of the washing water required for washing | cleaning of a predetermined area can be more reliably maintained constant, maintaining the washing | cleaning capability of a filter cloth belt.

  The cleaning device can clean a predetermined area of the filter cloth belt by discharging cleaning water while displacing the cleaning position by the cleaning position displacing means, and the filter cloth belt by displacing the cleaning position After the cleaning of the predetermined area is completed, the discharge control unit may control the discharge of the cleaning water to be turned off until the cleaning starts for the predetermined area adjacent to the downstream side of the predetermined area where the cleaning is completed. . If it does so, the waste of washing water can be prevented reliably while maintaining the washing ability of the filter cloth belt.

  When the filter cloth belt is traveling at a reference traveling speed, the cleaning position displacing means may not displace the cleaning position, and the discharge control means may always control the discharge of the cleaning water to be on.

  A concentrator that gravity concentrates while transporting sludge with an endless first filter cloth belt that travels on a circular track, and a pair of upper and lower second and third filter cloth belts disposed downstream of the concentrator. A dehydrating device that pressurizes and dewaters sludge between the nozzles, and the nozzles are provided to be able to wash the second and third filter cloth belts of the dewatering device, respectively, and the travel speed changing means is the concentrating device The traveling speed of the first filter cloth belt in the dewatering device can be set according to the setting, and the traveling speed of the second and third filter cloth belts can be set in accordance with the setting. The displacement speed of the cleaning position is controlled based on the difference in travel speed between the travel speed of the first filter cloth belt and the travel speed of the second and third filter cloth belts; The discharge of the washing water is controlled on and off based on the traveling speed difference It may be so. Then, the cleaning performance of the filter cloth belt and the amount of cleaning water used in the dehydrator are adjusted so that the cleaning performance of the filter cloth belt and the amount of cleaning water used in the concentrator are the same. Can be set. Thereby, the washing | cleaning operation | movement according to the concentration capacity | capacitance of a concentration apparatus and the dehydration capacity | capacitance of a dehydration apparatus as a whole system is attained, and the usage-amount of washing water can be reduced more.

  The traveling speed of the second and third filter cloth belts is set to be the same as or slower than the traveling speed of the first filter cloth belt, and the traveling speed of the first filter cloth belt and the second And when the traveling speed of the third filter cloth belt is set to be the same, the cleaning position displacement means does not displace the cleaning position, and the discharge control means always turns on the discharge of the cleaning water, When the traveling speeds of the second and third filter cloth belts are set slower than the traveling speed of the first filter cloth belt, the cleaning position displacing means moves the cleaning position according to the traveling speed difference. And the discharge control means may perform on / off control of the discharge of the cleaning water in accordance with the difference in the traveling speed. Then, it becomes possible to control the washing operation in consideration of the running speed difference between the running speed of the filter cloth belt of the concentrator and the running speed of the filter cloth belt of the dehydrator, and the total amount of washing water used in the entire system can be efficiently Can be reduced.

  The cleaning position displacing means may include a moving mechanism that moves the nozzle so that a predetermined area of the filter cloth belt can be cleaned.

  A plurality of nozzles may be provided side by side along the steering direction of the filter cloth belt, and the cleaning position may be displaced by sequentially turning on and off the plurality of nozzles by the discharge control means.

  The control method of the sludge dewatering system according to the present invention includes an endless filter cloth belt that travels on a circular track and separates solid and liquid while conveying sludge, and the filter cloth belt is cleaned by discharging cleaning water from a nozzle. A sludge dewatering system comprising a cleaning device, wherein a cleaning position of the filter cloth belt by the cleaning device is set in a longitudinal direction of the filter cloth belt at a displacement speed corresponding to a traveling speed of the filter cloth belt. The discharge of the washing water from the nozzle is controlled on and off while being displaced in the direction along the line.

  According to such a method, even when the traveling speed of the filter cloth belt is changed, it is possible to maintain a constant total amount of cleaning water while maintaining the cleaning ability of the cleaning water discharged from the nozzle. It becomes.

  The discharge pressure of the cleaning water from the nozzle and the discharge amount per unit time in the cleaning device are always set constant, and the relative speed between the traveling speed of the filter cloth belt and the displacement speed of the cleaning position is always constant. The displacement speed of the cleaning position is controlled so that the discharge time of the cleaning water required for cleaning with respect to a predetermined area of the filter cloth belt is always constant. May be.

  The sludge dewatering system includes a concentrator that concentrates gravity while conveying sludge with an endless first filter cloth belt that runs on a circular track, and is disposed on the downstream side of the concentrator. A dehydrating device for pressurizing and dewatering sludge between the third filter cloth belts, and the nozzles are respectively provided to be able to wash the second and third filter cloth belts of the dewatering device, The displacement speed of the cleaning position is controlled based on the traveling speed difference between the traveling speed of the filter cloth belt and the traveling speed of the second and third filter cloth belts, and the washing water is based on the traveling speed difference. The discharge may be controlled on and off.

  According to the present invention, the amount of cleaning water used for cleaning in a desired cleaning range can be made constant by turning on and off the discharge of cleaning water while appropriately displacing the cleaning position by the nozzle. Therefore, even when the traveling speed of the filter cloth belt is changed, it is possible to maintain the total amount of cleaning water used while maintaining the cleaning ability of the cleaning water discharged from the nozzles.

FIG. 1 is a side view showing an overall configuration of a sludge dewatering system according to an embodiment of the present invention. FIG. 2 is a plan view of the concentrating device constituting the sludge dewatering system shown in FIG. FIG. 3 is a block diagram showing the configuration of the control device of the sludge dewatering system shown in FIG. 1 and its control system. FIG. 4 is a side view schematically showing a state in which the filter cloth belt is washed while the washing position by the washing device is displaced by the washing position displacement portion. FIG. 5 is a side operation diagram schematically illustrating the cleaning operation of the filter cloth belt by the cleaning device, and FIG. 5A is a diagram illustrating a state in which a predetermined cleaning range is being cleaned. (B) is a diagram showing a state in which the nozzle is returned to the initial position after the completion of the cleaning of the predetermined cleaning range, and FIG. 5 (C) is for cleaning the next cleaning range with the nozzle returned to the initial position. FIG. FIG. 6 is a side view schematically showing a state in which the filter cloth belt is being washed while the washing position by the washing apparatus according to the first modification is displaced by the washing position displacement unit. FIG. 7 is a side view schematically showing a state in which the filter cloth belt is being washed while the washing position by the washing apparatus according to the second modification is displaced by the washing position displacement unit.

  Hereinafter, the sludge dewatering system according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to the control method.

1. Description of Overall Configuration of Sludge Dewatering System FIG. 1 is a side view showing the overall configuration of the sludge dewatering system 10 according to an embodiment of the present invention, and FIG. 2 is a concentration configuration of the sludge dewatering system 10 shown in FIG. 3 is a plan view of the device 12. FIG. The sludge dewatering system 10 according to the present embodiment is a sludge treatment facility for discharging sludge (for example, sewage sludge) by gravity with an upper concentration device 12 and then discharging it as a dehydrated cake by dehydrating with a lower dewatering device 14. It is.

  The sludge dewatering system 10 is a pair of a concentrating device 12 including a filtration unit 18 that gravity filters (gravity concentration) sludge on the upper surface 16a of the filter cloth belt 16 traveling on a circular track, and a sludge concentrated by the concentrating device 12. A dehydrating apparatus 14 that conveys the filter cloth while being sandwiched between the filter cloth belts 20 and 22 and performs pressure dehydration, and a control apparatus 15 that comprehensively controls the entire system are provided. Immediately before the concentrating device 12, a coagulation mixing tank 24 is provided for mixing the polymer flocculant (first chemical) F1 into the sludge transported from the preceding equipment of the sludge dewatering system 10. As the polymer flocculant F1, generally known ones may be used, and examples thereof include an anionic polymer flocculant and a cationic polymer flocculant.

1.1 Description of Concentration Device First, the concentration device 12 will be described.

  As shown in FIGS. 1 and 2, the concentrating device 12 includes a filtration unit 18 that gravity-filters the sludge charged from the flocculation / mixing tank 24 onto the upper surface 16 a of the filter cloth belt 16, and sludge that has been gravity-filtered by the filtration unit 18. And a pressure unit 28 that depressurizes and dehydrates the water to the lower dewatering device 14. A moving mechanism 30 that moves sludge in a direction that intersects (orthogonally in FIG. 2) the conveying direction by the filter cloth belt 16 is provided in the middle of the filtering unit 18.

  The filtration part 18 is comprised by the upper surface (outer peripheral surface) 16a of the endless filter cloth belt 16 wound around the some roller 19a, 19b, 19c, 19d, 19e, and drive | circulated in one direction. The filtration unit 18 is means for filtering and separating moisture contained in the sludge by gravity by placing the sludge on the upper surface 16a of the filter cloth belt 16 stretched between the rollers 19a and 19e.

  The filter cloth belt (first filter cloth belt) 16 is constituted by, for example, a long band-shaped filter cloth having water permeability, a long band-shaped metal screen in which a plurality of fine holes are formed in a mesh shape, and the like. It is wound around each roller 19a-19e with sufficient tension. The filter cloth belt 16 is driven by a predetermined drive roller (for example, a roller 19a) by a drive source such as a motor (not shown) provided in the upper drive unit 29, which is driven and controlled by the control device 15, so that FIG. The vehicle can travel in the direction of the arrow shown in the figure (counterclockwise in FIG. 1). That is, in FIGS. 1 and 2, the direction from the right side (upstream side) to the left side (downstream side) is the sludge transport direction in the concentrator 12.

  Therefore, the sludge thrown in and placed from the outlet port 24a of the flocculation / mixing tank 24 at the upstream position of the filtration unit 18 is transported downstream by the filter cloth belt 16, while only the moisture passes through the filter cloth belt 16 by gravity. Permeated, filtered and dehydrated, the filtered water (separated liquid, filtrate) is collected by the filtrate receiving trays 32a and 32b (see FIG. 1).

  A cleaning device 17 is provided in the middle of the orbit of the filter cloth belt 16 (between the rollers 19c and 19d in FIG. 1). The cleaning device 17 is a device for cleaning the filter cloth belt 16 by discharging cleaning water supplied from a cleaning water supply source (not shown) from the nozzle 17 a at a high pressure and spraying it onto the filter cloth belt 16.

  On the upper surface 16a of the filter cloth belt 16 constituting the filtration unit 18, a plurality of rod bodies 34 (a total of twelve configurations are illustrated before and after the moving mechanism 30 in FIG. 2) are erected. The rod 34 is an obstacle for abutting and dispersing the sludge transported on the filter cloth belt 16 to promote draining of the sludge, and its installation position, number, shape and the like can be appropriately changed. Note that a part of the rod body 34 installed on the upstream side of the screws 40 a and 40 b may be replaced with a roller (not shown) similar to the primary dewatering roller 26. In that case, it is preferable to provide a slight gap between the roller and the filter cloth belt 16, and the roller is used not for dehydration but for simple draining. There may be a plurality of the rollers.

  A second chemical injection device (medicine addition device) 36 for adding an iron-based inorganic flocculant (second chemical) F2 to the sludge to be conveyed is provided on the upstream side of the moving mechanism 30 in the filtration unit 18. ing. The second chemical injection device 36 includes a chemical tank 36a for storing the inorganic flocculant F2, and a first line 36c and a second line 36d branched from the outlet of the chemical tank 36a by a two-way valve 36b. As the inorganic flocculant F2, generally known ones may be used, and examples thereof include iron-based and aluminum-based ones.

  As shown in FIG. 2, in the present embodiment, the first line 36 c is further branched into two in parallel, and the two first lines 36 c and 36 c are arranged in the width direction of the filter cloth belt 16 at the upstream position of the moving mechanism 30. The addition nozzles 36e are provided in the vicinity of both side portions of the filter cloth belt 16, respectively. Of course, the first line 36a may be used as it is without branching. As indicated by a two-dot chain line in FIG. 1, the second line 36d is arranged so that the inorganic flocculant F2 can be added to the sludge charged into the flocculation mixing tank 24. Although not shown, the first line 36d is arranged. The configuration may be the same as that of the addition nozzle 36e of 36c. In the normal operation state of the present embodiment, the two-way valve 36b is controlled to be switched to the first line 36c side under the control of the control device 15.

  On the other hand, the above-described polymer flocculant F1 is added to the sludge immediately before being put into the agglomeration mixing tank 24 by the first chemical injection device (drug addition device) 38 in the normal operation state of the present embodiment. The first chemical injection device 38 includes a chemical tank 38a for storing the polymer flocculant F1, and a first line 38c and a second line 38d branched from the outlet of the chemical tank 38a by a two-way valve 38b.

  As shown in FIG. 1, the first line 38c can add the polymer flocculant F1 to the sludge charged into the flocculation mixing tank 24 at a position downstream of the second line 36d of the second chemical injection device 36. It is arranged. As shown by a two-dot chain line in FIG. 2, the second line 38 d extends in the width direction of the filter cloth belt 16 at a position upstream of the first line 36 c of the second chemical injection device 36, and the filter cloth belt 16. The addition nozzles 38e are provided in the vicinity of both side portions of each. In the normal operating state of the present embodiment, the two-way valve 38b is controlled to be switched to the first line 38c side under the control of the control device 15.

  During normal operation, the coagulation mixing tank 24 into which the sludge to which the polymer flocculant F1 is added from the first chemical injection device 38 is introduced has a tank 24b in which the sludge is stored, and the sludge in the tank 24b to the motor 24c. And a stirring blade 24d for stirring. The sludge in which the polymer flocculant F1 is sufficiently mixed in the tank 24b by the stirring blade 24d is put into the upper surface 16a of the filter cloth belt 16 from the outlet port 24a.

  Next, the moving mechanism 30 provided in the middle of the filtering unit 18 moves the sludge conveyed on the filter cloth belt 16 in the crossing direction, while reducing the width direction size and simultaneously increasing the sludge height. By doing so, the inorganic flocculant F2 added by the second chemical injection device 36 is sufficiently kneaded. Thereby, the filtration efficiency of the sludge in the concentration apparatus 12 and the dehydration apparatus 14 can be improved, and the sludge concentration can be increased.

  The moving mechanism (screw conveyor) 30 opens toward the entire upstream surface of the upper surface 16a of the filter cloth belt 16 and can accept sludge. The moving mechanism 30 is disposed close to a pair of screws 40a and 40b for moving sludge in a direction orthogonal to the conveying direction by the filter cloth belt 16 and downstream of the screws 40a and 40b. Are provided with a pair of guide plates 42a and 42b. In the moving mechanism 30, a gap between the guide plates 42 a and 42 b (substantially the same as the gap between the screws 40 a and 40 b) and a passage (sludge passage 43) for discharging sludge downstream from the moving mechanism 30. It has become.

  The screws 40a and 40b extend in a direction orthogonal to the sludge transport direction by the filter cloth belt 16 and extend across the filter cloth belt 16 in the width direction, and outer peripheral surfaces on both sides except for the vicinity of the center of the screw shaft 44. And screw blades 41a and 41b provided in a spiral shape.

  Both ends of the screw shaft 44 are pivotally supported at positions outside the filter cloth belt 16 in the width direction by a bearing (not shown). For example, a flexible power such as a chain or a belt is applied to the roller 19a around which the filter cloth belt 16 is wound. By being linked by the transmission member 39 (see the two-dot chain line in FIG. 1), it can be rotated as the filter cloth belt 16 travels. A drive source such as a motor that independently rotates the screw shaft 44 may be provided, and the drive source may be driven and controlled by the control device 15.

  The screw blades 41a and 41b are respectively provided on the outer peripheral surface of the screw shaft 44 at positions close to both sides in the width direction of the filter cloth belt 16, and the tips of the screw blades 41a and 41b are approximately the same as the gap between the guide plates 42a and 42b. It is opposed through a gap. The direction of the spiral of each screw blade 41a, 41b is a contrast shape (reverse direction) at the center line of the filter cloth belt 16, and the direction of sludge movement by each screw 40a, 40b is set in the opposite direction. Yes. For this reason, each screw 40a, 40b moves sludge from the outer side toward the inner side (center) in the width direction of the filter cloth belt 16, and at the center part where the tips are separated from each other via the gap, both outer sides The sludge moved from the above is pressed against each other to be compacted, and the inorganic flocculant F2 is sufficiently kneaded in the sludge.

  In the case of the present embodiment, the sludge that has been conveyed on the center side in the width direction of the filter cloth belt 16 to the central portion of the screw shaft 44, that is, the outer peripheral surface of the screw shaft 44 exposed between the screws 40a and 40b, and a pair of A plurality of paddles 45 for smoothly discharging the sludge consolidated in the center by the screws 40a, 40b to the downstream side are provided. The paddle 45 is, for example, an impeller provided in pairs on the outer peripheral surface of the screw shaft 44 along the circumferential direction.

  The guide plates 42a and 42b are provided on the downstream side of the screws 40a and 40b and at a position close to the screws 40a and 40b. It has a bottom portion 47 that covers the lower half of the screws 40a and 40b by curving and projecting toward the upstream side. A pair of passage plates 48a and 48b extending downstream along the sludge transport direction by the filter cloth belt 16 are provided at the center ends of the guide plates 42a and 42b, respectively. The gap between the guide plates 42a and 42b is located on the front side in the direction of sludge movement by the screws 40a and 40b, and this gap forms a sludge passage 43 for discharging the sludge downstream. Yes.

  The wall portion 46 is a plate-like member set to a height approximately equal to the height of the screws 40a and 40b, and the height can be changed as appropriate. As shown in FIG. 1, the bottom portion 47 is a plate-like member that protrudes from the lower end of the wall portion 46 toward the upstream side in the transport direction to a position that is approximately the center of the screws 40 a and 40 b, and has a length. Can be appropriately changed. For the wall portion 46 and the bottom portion 47 constituting the guide plates 42a and 42b, a screen or the like in which many fine holes are formed may be used.

  The passage plates 48a and 48b are erected so as to face each other with a gap having the same width as the gap formed between the screw blades 41a and 41b and between the guide plates 42a and 42b. The passage plates 48a and 48b are wall members that form a passage for smoothly discharging sludge, which is compacted near the center of the filter cloth belt 16 by the screws 40a and 40b, to the downstream side. Set to a height of about.

  The pressurizing unit 28 constitutes a pre-stage dehydrating unit (primary dehydrating unit) of the dehydrating device 14 disposed below the concentrating device 12, and an outer peripheral surface thereof is pressed against the filter cloth belt 16. A primary dewatering roller 26 is provided.

  The sludge that has been filtered and concentrated by the filtration unit 18 and sufficiently mixed with the inorganic flocculant F2 by the moving mechanism 30 and increased in height by compaction is separated between the primary dewatering roller 26 and the filter cloth belt 16 by the pressurization unit 28. After the pressure dehydration between the two, it is discharged / dropped from the outlet of the pressurizing unit 28 (the outlet of the concentrating device 12), and put into the dehydrating device 14 in the next step. The pressurizing unit 28 crushes the sludge that has been consolidated by the moving mechanism 30 and gathered in the center, and sends it to the dehydrating device 14 in a state where it has been expanded again in the width direction of the filter cloth belt 16. It also has a function of increasing the dewatering area of the sludge to be added and improving the dewatering efficiency here.

  As shown in FIG. 1, an inclined plate 49 is disposed between the pressurizing unit 28 and the dehydrating device 14 below the pressurizing unit 28. The inclined plate 49 is a guide for smoothly guiding the sludge discharged / dropped from the concentrating device 12 onto the filter cloth belt 22 serving as a loading position of the dehydrating device 14.

1.2 Description of Dehydration Device Next, the dehydration device 14 will be described.

  As shown in FIG. 1, the dehydrating device 14 includes a dehydrating unit 50 that depressurizes and dewaters the sludge introduced from the outlet of the concentrating device 12 through the inclined plate 49 while being transported between the pair of filter cloth belts 20 and 22. The squeezing part 52 further pressurizes and squeezes the sludge dehydrated by the dehydrating part 50. The dehydrator 14 has a configuration substantially similar to that of a general belt press type dehydrator.

  The lower filter cloth belt (second filter cloth belt) 20 is, for example, a long band-shaped filter cloth having water permeability, or a long band-shaped metal screen in which a plurality of fine holes are formed in a mesh shape. Composed of etc. The filter cloth belt 20 is wound around a plurality of rollers 21a, 21b, 21c, 21d, 21e, 21f, 21g, 21h, 21i, 21j, 21k, 21l, 21m, and 21n with sufficient tension. The filter cloth belt 20 is driven by a predetermined driving roller (for example, a roller 21a) rotated by a driving source such as a motor (not shown) provided in the lower driving unit 33 that is driven and controlled by the control device 15, so that FIG. The vehicle can travel in the direction of the arrow shown in the figure (clockwise in FIG. 1).

  For the upper filter cloth belt (third filter cloth belt) 22 as well, for example, a long belt-like filter cloth having water permeability and a long belt-like metal screen in which a plurality of fine holes are formed in a mesh shape. Composed of etc. The filter cloth belt 22 is wound around a plurality of rollers 21o, 21b, 21c, 21d, 21e, 21f, 21g, 21h, 21i, 21j, 21p, 21q with sufficient tension. The filter cloth belt 22 is driven by a predetermined drive roller (for example, a roller 21o) rotated by a drive source such as a motor (not shown) provided in the lower drive unit 33 that is driven and controlled by the control device 15. The vehicle can travel in the direction of the arrow shown in the figure (counterclockwise in FIG. 1).

  A portion where the outer peripheral surfaces (surfaces) of the lower filter cloth belt 20 and the upper filter cloth belt 22 between the rollers 21b to 21i are in contact with or close to each other while being meandering up and down constitutes the dewatering unit 50. During this time, the sludge is sufficiently dehydrated under pressure. Further, the portion where the outer peripheral surfaces (surfaces) of the lower filter cloth belt 20 and the upper filter cloth belt 22 between the rollers 21j and 21p are in contact with each other or close to each other constitutes the pressing part 52. In the pressing part 52, sludge is further pressurized and compressed between the rollers 21j and 21p serving as pressing rollers, and is discharged to the outside as a dehydrated cake having a desired moisture content.

  A cleaning device 23 is provided in the middle of the orbit of the filter cloth belt 20 (between the rollers 21m and 21n in FIG. 1), and in the middle of the orbit of the filter cloth belt 22 (between the rollers 21p and 21q in FIG. 1). A cleaning device 25 is provided. The cleaning devices 23 and 25 discharge cleaning water supplied from a cleaning water supply source (not shown) from the nozzles 23a and 25a at high pressure and spray the cleaning water onto the filter cloth belts 20 and 22, respectively. It is a device.

  In the vicinity of the inlet of the dewatering device 14, the height of the sludge dropped and introduced from the outlet of the concentrating device 12 onto the filter cloth belt 20 is made uniform to some extent, and a dewatering section formed between the filter cloth belts 20 and 22. A leveling plate 51 is provided for smooth introduction into the 50 inlets 50a. The leveling plate 51 is a plate member that is disposed slightly upstream on the downstream side of the sludge dropping position from the concentrating device 12 onto the filter cloth belt 20, and that is gradually inclined downward toward the inlet 50a and presses the sludge downward. You may form with the leaf | plate spring member urged | biased to the direction.

  At the outlet of the dewatering device 14, a discharge tray 54 is installed in an inclined posture with the rear end lowered so as to be close to the filter cloth belt 20 running on the outer peripheral surface of the roller 21 j. The dehydrated cake is discharged while sliding on the discharge tray 54. Above the discharge tray 54, a scraper (scraping plate) 56 is installed in an inclined posture with the rear end raised so as to be close to the filter cloth belt 22 running on the outer peripheral surface of the roller 21p. The sludge that is not discharged to the discharge tray 54 from between the rollers 21j and 21p but remains attached to the upper filter cloth belt 22 is scraped off by the scriber 56 and discharged to the discharge tray 54. The sludge that remains attached to the lower filter cloth belt 20 is scraped off by the discharge tray 54 and slides down on the discharge tray 54 as it is.

  In such a dewatering device 14, the sludge introduced from the concentrating device 12 onto the filter cloth belt 20 is drawn between the filter cloth belts 20 and 22 constituting the dewatering unit 50 from the inlet 50 a and is sandwiched and pressurized. In the state, it is conveyed downstream. During this time, only moisture passes through the filter cloth belt 20 by the pressure applied by the two filter cloth belts 20 and 22, and is filtered and dehydrated. Further, after being squeezed by the squeezing unit 52, it is discharged onto the discharge tray 54 as a dehydrated cake. The water filtered by the dewatering unit 50 and the pressing unit 52 passes through the filter cloth belt 20 and falls, and is collected by the filtrate receiving tray 58.

  As shown in FIG. 1, in the sludge dewatering system 10 according to the present embodiment, the filter cloth belt 16 of the concentrating device 12 and the filter cloth belts 20 and 22 of the dewatering device 14 are not combined, and each is an independent endless track. It is configured to run. For this reason, the upper drive unit 29 and the lower drive unit 33 are appropriately driven and controlled under the control of the control device 15, so that the traveling speed of the filter cloth belt 16 of the preceding concentration device 12 and the filter cloth of the subsequent dehydration device 14 are controlled. The running speed of the belts 20 and 22 can be easily controlled to a different speed.

  In this case, it is preferable to set and control the traveling speeds of the filter cloth belts 20 and 22 of the dehydrator 14 to be lower than the traveling speed of the filter cloth belt 16 of the concentrating device 12. That is, in the sludge dewatering system 10, since the moving mechanism 30 is mounted on the concentrating device 12, the dewatering rate is significantly increased as compared with the conventional concentrating device, and as a result, the sludge that is input to the dewatering device 14. The amount of cake (the amount of cake) can be significantly reduced, and even if the traveling speed of the filter cloth belts 20 and 22 in the dehydrating device 14 is slowed down, it is possible to sufficiently dehydrate the total amount of sludge to be charged. It has become. Then, by slowing the traveling speed of the filter cloth belts 20 and 22 in the dehydrator 14, the time required to pass between the filter cloth belts 20 and 22 during the dehydration can be lengthened, and the dehydrator 14 has a compact configuration. However, high dewatering performance can be obtained.

1.3 Description of Control Device and its Control System Next, the control device 15 and the control system by the control device 15 will be described.

  FIG. 3 is a block diagram showing the configuration of the control device 15 and the control system of the sludge dewatering system 10 shown in FIG. As shown in FIG. 3, the control device 15 includes a belt drive control unit 60, a cleaning position control unit 62, and a discharge control unit 64, and is based on a predetermined control program stored in the storage unit 66. The overall control of the sludge dewatering system 10 is performed while controlling the operation of the dewatering device 12 and the dewatering device 14.

  The belt drive control unit (belt drive control means) 60 operates the upper drive unit 29 and the lower drive unit 33 based on the travel speed setting values of the filter cloth belts 16, 20, and 22 set by the travel speed changing unit 68. Control. Accordingly, the filter cloth belts 16, 20, and 22 are driven and controlled so as to travel at the set traveling speed set values. The travel speed changing unit (travel speed changing means) 68 is configured by an input operation means such as a keyboard or a dial type. The setting of the traveling speed in the traveling speed changing unit 68 is changed before the operation of the sludge dewatering system 10 is started, for example, according to the property of the sludge to be processed.

  The cleaning position control section (cleaning position control means) 62 drives and controls the cleaning position displacement section 70 provided in each of the cleaning apparatuses 23 and 25 on the dehydrating apparatus 14 side. The cleaning position displacement section (cleaning position displacement means) 70 controlled by the cleaning position control section 62 includes, for example, a pendulum that moves the nozzle 23a (25a) along the longitudinal direction of the filter cloth belt 20 (22) as shown in FIG. A cleaning mechanism (moving mechanism) 72 that swings in a shape is provided, and the cleaning position by the nozzle 23a (25a) can be displaced within a desired range at a desired displacement speed. A specific configuration of the cleaning position displacement unit 70 will be described later.

  The discharge control unit (discharge control means) 64 performs on / off control of the discharge of the cleaning water from the nozzles 17a, 23a, 25a of the cleaning devices 17, 23, 25. As shown in FIG. 4, the discharge controller 64 includes an electromagnetic on-off valve 76 provided in the middle of a supply hose 74 from a cleaning water supply source (not shown) connected to the nozzle 23a (25a) of the cleaning device 23 (25). Cleaning water discharge control is performed by opening and closing control. Although not shown, the cleaning device 17 is also provided with an electromagnetic open / close valve in the middle of the supply hose for the cleaning water to the nozzle 17 a, and this electromagnetic open / close valve is controlled to open and close by the discharge control unit 64.

  The storage unit 66 is, for example, a readable / writable memory. The storage unit 66 stores an operation control program for the concentrator 12 and the dehydrator 14, an operation control program for the cleaning devices 17, 23, 25, and the like. Furthermore, the storage unit 66 also stores travel speed setting values of the filter cloth belts 16, 20, and 22 that are changed by the travel speed change unit 68.

2. Next, the configuration and operation of the cleaning devices 17, 23, and 25 will be described.

  First, the cleaning device 17 provided in the concentration device 12 will be described. The cleaning device 17 is a device that cleans the filter cloth belt 16 by discharging high-pressure cleaning water from the nozzle 17 a accommodated in the cleaning case and spraying it onto the filter cloth belt 16. For example, a plurality of nozzles 17 a are juxtaposed along the width direction of the filter cloth belt 16, and the washing water can be sprayed over the entire width direction of the filter cloth belt 16. By appropriately setting the shape of the discharge port of the nozzle 17a, the entire region in the width direction of the filter cloth belt 16 may be washed with one nozzle 17a. In the cleaning device 17, the electromagnetic on / off valve is controlled to open / close under the control of the discharge control unit 64, and the discharge of the cleaning water from the nozzle 17 a is controlled to be on / off.

  The nozzle 17a of the cleaning device 17 cleans the dirt adhering to the filter cloth belt 16 by continuously spraying the cleaning water on the filter cloth belt 16 traveling on the circular track at a predetermined fixed position. In the present embodiment, the traveling speed of the filter cloth belt 16 of the concentration device 12 is set to, for example, 0.75 m / min, and the cleaning position of the nozzle 17a is fixed at a fixed position. 0.75 m of the filter cloth belt 16 can be washed.

  At this time, since the displacement speed of the cleaning position by the nozzle 17a fixed at a fixed position is zero (0 m / min), the relative speed between the displacement speed and the traveling speed of the filter cloth belt 16 (0.75 m / min). Is 0.75 m / min, and the filter cloth belt 16 passes through the washing position of the washing water with this relative speed. That is, in the cleaning device 17, the cleaning water discharge pressure (MPa) and the discharge flow rate (L (liter) / min) from the nozzle 17 a contact the cleaning water and the filter cloth belt 16 at the relative speed of 0.75 m / min. In this case, the dirt on the filter cloth belt 16 can be sufficiently washed, and the use amount (L (liter) / min) of washing water per unit time required for washing within a predetermined washing range or one round is minimized. Is set to the set value.

  In the case of the sludge dewatering system 10 according to the present embodiment, the three cleaning devices 17, 23, 25 have the nozzles 17a, 23a, 25a regardless of the traveling speed of the filter cloth belts 16, 20, 22 to be cleaned. The discharge pressure (MPa) and the discharge flow rate (L / min) of the cleaning water from are controlled so as to be always constant at the same preset value. The discharge pressure and the discharge flow rate in each of the cleaning devices 17, 23, and 25 may be changed depending on the properties of the sludge introduced into the sludge dewatering system 10, and the cleaning device 17 on the concentration device 12 side. And the cleaning devices 23 and 25 on the dehydrator 14 side may have different set values.

  Next, the cleaning devices 23 and 25 provided in the dehydrator 14 will be described.

  FIG. 4 is a side view schematically showing a state in which the filter cloth belt 20 is being cleaned while the cleaning position by the cleaning device 23 is displaced by the cleaning position displacement unit 70. In addition, since the structure and operation | movement of the washing | cleaning apparatus 25 and the washing | cleaning position displacement part 70 with which this was equipped are the same as that of the washing | cleaning apparatus 23, it represents below about the washing | cleaning apparatus 23 and the washing position displacement part 70 with which this was equipped. I will explain it.

  As shown in FIG. 4, the cleaning device 23 is a device that cleans the filter cloth belt 20 by discharging cleaning water from the nozzles 23 a housed in the cleaning case 27 and spraying the water onto the filter cloth belt 20. The nozzle 23 a is connected to a supply hose 74 extending from a cleaning water supply source (not shown) via a cleaning position displacement unit 70. The supply hose 74 is provided with an electromagnetic on-off valve 76 at a position upstream of the cleaning position displacement unit 70. For example, a plurality of nozzles 23 a are arranged in parallel along the width direction of the filter cloth belt 20, and the washing water can be sprayed over the entire width direction of the filter cloth belt 20. By appropriately setting the shape of the discharge port of the nozzle 23a, the entire region in the width direction of the filter cloth belt 20 may be washed with one nozzle 23a. In the cleaning device 23, the discharge of the cleaning water from the nozzle 23 a is controlled on and off under the control of the discharge controller 64. Further, the cleaning device 23 is controlled to drive the cleaning position displacement unit 70 under the control of the cleaning position control unit 62, thereby displacing the cleaning position by the nozzle 23 a along the longitudinal direction of the filter cloth belt 20. Washing can be carried out by spraying washing water (predetermined range).

  The cleaning position displacement unit 70 includes a swing mechanism 72. The swing mechanism 72 has a swing shaft portion 71 that supports a base end portion of the nozzle 23a so as to be swingable via a drive source such as a motor (not shown), and the cleaning position W by the nozzle 23a is set on the filter cloth belt 20. It is displaced along the longitudinal direction.

  In the present embodiment, as shown in FIG. 4, the cleaning start position (position P <b> 1) that is the initial position of the nozzle 23 a is set at the downstream end of the cleaning range A with respect to the filter cloth belt 20. In the cleaning device 23, the filter mechanism belt is driven while swinging the nozzle 23 a in the opposite direction (the right side in FIG. 4) to the traveling direction of the filter cloth belt 20 (the left side in FIG. 4). Twenty cleanings can be performed. After the nozzle 23a reaches the cleaning end position (position P2) (see the nozzle 23a and the cleaning position W indicated by the two-dot chain line in FIG. 4) and the cleaning of the cleaning range A is completed, the nozzle 23a is moved by the swing mechanism 72. Is again returned to position P1 and waits for the next cleaning area to be cleaned. Depending on the traveling speed of the filter cloth belt 20, the cleaning position displacement unit 70 may stop the swing mechanism 72 and clean the filter cloth belt 20 with the nozzle 23a fixed at the position P1. In addition, you may set the displacement direction at the time of washing | cleaning of the nozzle 23a to the reverse direction (direction along the running direction of the filter cloth belt 20) with the above.

  Next, the cleaning operation of the filter cloth belt 20 (22) using the cleaning device 23 (25) and the cleaning position displacement unit 70 will be described.

  In the sludge dewatering system 10, assuming that the traveling speed of the filter cloth belt 16 of the upper concentration device 12 is the reference traveling speed, the traveling speed of the filter cloth belts 20 and 22 of the lower dewatering device 14 is the same as this reference traveling speed. Set to a slower speed. For example, when the reference traveling speed, which is the traveling speed of the upper filter cloth belt 16, is set to 0.75 m / min, the traveling speed of the lower filter cloth belts 20 and 22 is preset by the traveling speed changing unit 68. Is set to about 0.25 to 0.75 m / min depending on the properties of the sludge.

  Therefore, based on the predetermined cleaning range or the amount of cleaning water used per unit time (L / min) required for one round of cleaning for the filter cloth belt 16 traveling at a traveling speed of 0.75 m / min in the concentrator 12. The amount of cleaning water used per unit time required for cleaning the predetermined cleaning range A or one round for the filter cloth belts 20 and 22 traveling at a traveling speed of 0.25 to 0.75 m / min in the dehydrator 14. If (L / min) is the same, the filter cloth belts 20 and 22 can be sufficiently washed with the minimum required amount.

  However, in the lower dewatering device 14, the traveling speed of the filter cloth belt 20 is set to be the same as or slower than the traveling speed of the upper filter cloth belt 16. For this reason, when the set value is the same as the discharge pressure and discharge flow rate of the nozzle 17a described above at a fixed position without displacing the nozzle 23a, the filter cloth belt 20 requires a predetermined cleaning range or one round of cleaning. The usage amount (L / min) per unit time of the cleaning water becomes, for example, about three times per revolution, and the total usage amount (L) of the cleaning water increases. On the other hand, if the discharge pressure and flow rate of the nozzle 17a are set to the same set values and the discharge of the cleaning water from the nozzle 23a is simply controlled to be turned on / off, the entire length of the filter cloth belt 20 cannot be cleaned, resulting in a cleaning leak point. It will be.

  Therefore, in the present embodiment, first, with respect to the cleaning device 23 (25) for cleaning the lower filter cloth belt 20 (22), the discharge pressure and the discharge flow of the cleaning water from the nozzle 23a (25a) are the same as the upper cleaning device 17. The cleaning performance is ensured as the same set value as in this case, and this set value is always set constant regardless of the traveling speed of the filter cloth belt 20 (22).

  Next, the cleaning position displacement unit 70 is driven and controlled under the control of the cleaning position control unit 62 to displace the cleaning position W of the nozzle 23a (25a) within the predetermined cleaning range A, and at the same time, the discharge control unit 64 is controlled. The electromagnetic on / off valve 76 is controlled to open / close downward. Specifically, the discharge control unit 64 performs cleaning required for cleaning a predetermined area (for example, one turn or cleaning range A) of the filter cloth belt 20 (22) regardless of the traveling speed of the filter cloth belt 20 (22). The electromagnetic on-off valve 76 is on / off controlled so that the water discharge on-time is always constant, and the total amount of cleaning water used is kept constant to prevent the increase. At the same time, the cleaning position displacement unit 70 is controlled to displace the cleaning position, thereby preventing the occurrence of cleaning leakage.

  Hereinafter, the traveling speed of the filter cloth belt 20 (22) is set to three types of 0.75 m / min (first condition), 0.5 m / min (second condition), and 0.25 m / min (third condition). The cleaning operation of the filter cloth belt 20 by the cleaning device 23 will be described by exemplifying the case where each is set.

  FIG. 5 is a side operation diagram schematically showing the cleaning operation of the filter cloth belt 20 by the cleaning device 23, and FIG. 5 (A) is a diagram showing a state where a predetermined cleaning range A1 is being cleaned. FIG. 5B is a diagram showing a state in which the nozzle 23a is returned to the initial position after completion of the cleaning in the cleaning range A1, and FIG. 5C is a diagram illustrating the next cleaning by the nozzle 23a returned to the initial position. It is a figure which shows the state which wash | cleans range A2.

  First, when the filter cloth belt 20 is traveling at the reference traveling speed of 0.75 m / min (first condition), the cleaning device 23 operates the cleaning position displacement unit 70 under the control of the cleaning position control unit 62. Is stopped, the nozzle 23a is fixed at the initial position P1, and the discharge controller 64 always controls the discharge of the washing water from the nozzle 23a while the filter cloth belt 20 is running. As a result, the filter cloth belt 20 has the same cleaning performance as the cleaning operation of the filter cloth belt 16 by the cleaning device 17, and the use amount (L / min) of cleaning water required for cleaning the predetermined cleaning range A1 or one round. It will be the same.

  Next, when the filter cloth belt 20 is traveling at 0.25 m / min, which is 1/3 of the reference traveling speed (third condition), the cleaning device 23 is under the control of the cleaning position control unit 62. The operation of the cleaning position displacement unit 70 is controlled, and at the same time, the discharge of the cleaning water is on / off controlled under the control of the discharge control unit 64.

  That is, as shown in FIG. 5A, the nozzle 23a moves from the position P1, which is the cleaning start position, to the position P2, which is the cleaning end position, at the traveling speed (0.25 m / min) of the filter cloth belt 20. It is driven to swing at a corresponding displacement speed (m / min). Here, the use amount (L / min) and the total use amount (L) of the cleaning water used for cleaning in the cleaning range A are set to be the same as those in the first condition even in the case of the third condition. Need to be done. Therefore, the cleaning position control unit 62 always maintains the relative speed (m / min) between the traveling speed of the filter cloth belt 20 and the displacement speed of the nozzle 23a regardless of the traveling speed of the filter cloth belt 20. In the third condition, the discharge of the cleaning water from the nozzle 23a is controlled to be ON only until the cleaning of the cleaning range A1 is completed.

  Therefore, under the third condition, the displacement speed of the nozzle 23a during the cleaning shown in FIG. 5A is set to 0.5 m / min, so that the travel speed of the filter cloth belt 20 and the displacement speed of the nozzle 23a are reduced. The relative speed is 0.75 m / min, which is the same as the first condition. Then, in the first condition, it takes 1 minute to clean the cleaning range A1 corresponding to the length of 0.75 m of the filter belt 20, whereas in the third condition, the length of the filter belt 20 is 0. It takes 1 minute to clean the cleaning range A of 75 m. Therefore, for example, if the cleaning range A1 in FIG. 5A is 0.75 m, it takes one minute for the cleaning position of the nozzle 23a to be displaced from the position P1 to the position P2, and this one minute The cleaning of the cleaning range A1 of the filter cloth belt 20 is completed under the same conditions as in the first condition.

  However, in the third condition, the filter cloth belt 20 has actually advanced only 0.25 m when 1 minute has passed to complete the cleaning of the cleaning range A1 (see FIG. 5B). For this reason, the remaining cleaning time A1 is 0.5 m before the cleaning range A1 that has been cleaned passes the position P1 that becomes the next cleaning range by the nozzle 23a, that is, 2 minutes is a standby time that does not require discharge of cleaning water. Therefore, as shown in FIG. 5B, the cleaning position displacement unit is controlled under the control of the cleaning position control unit 62 while the discharge control unit 64 controls the discharge of the cleaning water from the nozzle 23a during the standby time. 70 is controlled, and the nozzle 23a is returned to the original cleaning start position P1. It should be noted that the displacement speed of the nozzle 23a during the returning operation may be set to a speed at which the nozzle 23a can return to the initial position during the standby time.

  Subsequently, as shown in FIG. 5C, when the downstream end of the next cleaning range A2 reaches the cleaning position P1, the cleaning operation of the filter cloth belt 20 by the nozzle 23a is performed again. This cleaning operation is performed in the same manner as in the previous cleaning range A1, and the cleaning operation as shown in FIGS. 5A to 5C is repeatedly executed while the filter cloth belt 20 is traveling. As a result, the filter cloth belt 20 can be cleaned with the same discharge pressure, discharge flow rate, and total amount used as in the first condition even in the third condition.

  Note that when the filter cloth belt 20 is traveling at a speed of 0.5 m / min, which is 2/3 of the reference traveling speed (second condition), the control is performed in the same manner as in the third condition. Therefore, under the second condition, as shown in FIG. 5A, the nozzle 23a moves from the position P1 that is the cleaning start position toward the position P2 that is the cleaning end position (0. The nozzle 23a is driven to swing at a displacement speed corresponding to 5 m / min). Therefore, under the second condition, the displacement speed of the nozzle 23a during cleaning shown in FIG. 5A is set to 0.25 m / min, so that the traveling speed of the filter cloth belt 20 and the displacement speed of the nozzle 23a The relative speed of 0.75 m / min is the same as the first condition and the third condition. Then, the discharge of the cleaning water is on-controlled only while the cleaning position of the nozzle 23a is displaced from the position P1 to the position P2. Thereby, the washing | cleaning of the washing | cleaning range A1 of the filter cloth belt 20 can be completed on the same conditions as the case of the 1st condition and the 3rd condition, and it is the same as that of the case of the 3rd condition also about the following washing | cleaning range A2.

3. Description of Modification Example of Cleaning Device In the above, the configuration in which the nozzles 23a and 25a are displaced by the cleaning position displacement unit 70 using the swing mechanism 72 is illustrated. However, the cleaning device and the cleaning position displacement unit that displaces the nozzle are other types. It may be a configuration.

3.1 Description of cleaning device according to first modification

  FIG. 6 is a side view schematically showing a state in which the filter cloth belt 20 (22) is being washed while the washing position by the washing apparatus 80 according to the first modification is displaced by the washing position displacement unit 82.

  As shown in FIG. 6, the cleaning device 80 is configured so that the nozzle 23 a (25 a) can be slid in parallel along the longitudinal direction of the filter cloth belt 20 (22) in the cleaning case 27. In the cleaning device 80, the nozzles 23a (25a) are installed in a direction orthogonal to the filter cloth belt 20 (22). The cleaning position displacement portion 82 that slides and displaces the nozzles 23 a (25 a) has an expansion / contraction mechanism (movement mechanism) 84 provided in a part of the supply hose 74. The expansion / contraction mechanism 84 is constituted by a retractable hose formed by, for example, a bellows or a winding / feeding mechanism of the supply hose 74. By using such a cleaning position displacement portion 82, the filter cloth belts 20 and 22 can be cleaned while displacing the cleaning position of the nozzle 23a (25a).

3.2 Description of the cleaning apparatus according to the second modification

  FIG. 7 is a side view schematically showing a state in which the filter cloth belt 20 (22) is being cleaned while the cleaning position by the cleaning device 86 according to the second modification is displaced by the cleaning position displacement unit 88. FIG.

  As shown in FIG. 7, the cleaning device 86 has a plurality (six in FIG. 7) of nozzles 23 a (25 a) arranged in the cleaning case 27 along the longitudinal direction of the filter cloth belt 20 (22). . The respective nozzles 23a (25a) are arranged in a positional relationship such that the ranges of the respective cleaning positions W are somewhat overlapped with each other, and the cleaning water is discharged from all of the nozzles 23a (25a), so that the entire area of the cleaning range A is covered. It can be washed. In the cleaning device 86, each nozzle 23a (25a) is installed in a direction orthogonal to the filter cloth belt 20 (22), and a supply hose 74 and an electromagnetic on-off valve 76 are connected to each nozzle 23a (25a). ing.

  The cleaning position displacing unit 88 sequentially controls each electromagnetic on-off valve 76 to each nozzle 23a (25a) by the cleaning position control unit 62 linked with the discharge control unit 64. That is, when cleaning the cleaning range A of the filter cloth belt 20 (22), the cleaning position control unit 62 is linked to the discharge control unit 64, and the cleaning position displacement unit 88 is responsible for the position P1 that is the cleaning start position. The nozzle 23a (25a) from the left end nozzle 23a (25a) to the position P2 which is the end point of cleaning in FIG. 7 is controlled so that the cleaning water is discharged in order for each nozzle 23a (25a) from the nozzle 23a (25a) at the right end in FIG. To do. By appropriately controlling the discharge time and switching time of each nozzle 23a (25a), the traveling speed and the cleaning position of the filter cloth belt 20 (22) are the same as in the case of the cleaning position displacement portions 70 and 82 described above. The filter cloth belts 20 and 22 can be washed while displacing the washing position of the nozzle 23a (25a) by controlling the relative speed between the displacement speed of W to be constant.

4). Operation and Control Method and Effect of Sludge Dewatering System Next, the operation and effect of the sludge dewatering system 10 configured as described above will be described.

  First, the sludge that is the object to be concentrated and dewatered by the sludge dewatering system 10 is added to the flocculation mixing tank 24 with the predetermined polymer flocculant F1 added by the first line 38c of the first chemical injection device 38. be introduced. The sludge introduced into the tank 24b of the agglomeration mixing tank 24 is sufficiently stirred and mixed by the stirring blade 24d to form a floc, and from the outlet port 24a to the upstream side of the upper surface 16a of the filter cloth belt 16, that is, the inlet of the concentrating device 12. It is thrown into.

  The sludge thrown into the concentrating device 12 is conveyed through the filtration unit 18 by the traveling filter cloth belt 16 and gravity filtered (gravity dehydration) while receiving a draining promoting action by the rod body 34 on the way. During this time, as shown in FIGS. 2 and 3, a predetermined inorganic flocculant F2 is dripped from the addition nozzle 36e of the second chemical injection device 36 to the sludge conveyed on both sides in the width direction of the filter cloth belt 16. Meanwhile, the sludge reaches the moving mechanism 30.

  When the sludge which is conveyed on both sides in the width direction of the filter cloth belt 16 and is added to the rotation of the screws 40a and 40b is added to the belt in which the inorganic flocculant F2 is continuous in the conveying direction, the guide plates 42a and 42b It moves while being pushed toward the center while being guided. Then, the sludge moved by the screws 40a and 40b with the inorganic flocculant F2 is mixed with the sludge that has been transported through the central portion (center portion) of the filter cloth belt 16. At the same time, sludges are crushed and consolidated in the center of the filter cloth belt 16 by the pressing force of the screws 40a and 40b. As a result, the sludge is passed through the sludge passage 43 from the passage plates 48a and 48b to the downstream side while the rotational force of the paddle 45 is applied while the width direction dimension is reduced and the height (bulk) is increased. During this time, gravity filtration by the filter cloth belt 16 is continued and concentrated to a desired concentration. Thereby, the concentration density | concentration of the sludge in the concentration apparatus 12 increases significantly compared with the case where only normal gravity filtration is received with the general concentration apparatus.

  The sludge consolidated by the moving mechanism 30 is transported further downstream and introduced into the pressurizing unit 28 while receiving drainage promoting action by the rod 34 on the downstream side. The sludge that has been introduced into the pressurizing unit 28 and spread flatly and further concentrated is then dropped and introduced to the inlet side of the dehydrator 14.

  The sludge thrown into the dehydrator 14 is leveled by the leveling plate 51 while being transported by the traveling filter cloth belt 22, and is first introduced into the dewatering unit 50 from the inlet 50a. In the dewatering unit 50, the sludge is nipped and pressurized between a pair of upper and lower filter cloth belts 20, 22 that meander and is transported while being efficiently dehydrated, and then introduced into the pressing unit 52. In the squeezing section 52, the sludge is sandwiched between the pair of filter cloth belts 20 and 22, and is strongly pressed and squeezed between the rollers 21j and 21p serving as squeezing rollers to form a dehydrated cake having a desired moisture content, and discharged. The paper is discharged from the tray 54 to the outside of the system.

  During the sludge concentration / dehydration process, the filter cloth belts 16, 20, and 22 driven by the upper drive unit 29 and the lower drive unit 33 are moved while the cleaning devices 17, 23, and 25 (80, 86), the clogging of the filter cloth is eliminated by the washing operation using the minimum washing water, and the sludge filtration efficiency is stably maintained.

  As described above, in the sludge dewatering system 10 according to the present embodiment, the traveling speed changing unit 68 that changes the traveling speed of the filter cloth belts 20 and 22 and the displacement speed according to the traveling speed of the filter cloth belts 20 and 22 are used. A cleaning position displacement section 70 (82, 88) for displacing the cleaning position W of the filter cloth belts 20, 22 by the cleaning devices 23, 25 in the direction along the longitudinal direction of the filter cloth belts 20, 22, and the filter cloth belt 20. , 22 according to the traveling speed of the nozzles 23a, 25a. In the control method of the sludge dewatering system according to the present embodiment, the cleaning position W of the filter cloth belts 20 and 22 by the cleaning devices 23 and 25 is set at the displacement speed corresponding to the traveling speed of the filter cloth belts 20 and 22. The discharge of the cleaning water from the nozzles 23a and 25a is controlled on and off while being displaced in the direction along the longitudinal direction of the nozzles 20 and 22.

  Thus, in the sludge dewatering system 10, even when the traveling speed of the filter cloth belts 20 and 22 is changed depending on the properties of the sludge to be treated, the cleaning position W of the nozzles 23a and 25a is displaced by the cleaning position displacement unit 70. The discharge of the cleaning water can be controlled on and off according to the traveling speed of the filter cloth belts 20 and 22. Thus, the amount of cleaning water used for cleaning in the desired cleaning range A can be made constant by turning on and off the discharge of cleaning water while appropriately displacing the cleaning position W by the nozzles 23a and 25a. Accordingly, even when the traveling speed of the filter cloth belts 20 and 22 is changed, the filter cloth is maintained while maintaining the desired cleaning performance by setting the discharge pressure and discharge flow of the cleaning water from the nozzles 23a and 25a constant. It is possible to maintain a constant total amount of cleaning water required for cleaning one belt or cleaning a predetermined area of the filter cloth belt.

  The cleaning devices 23 and 25 are set so that the discharge pressure and the discharge flow rate of the cleaning water from the nozzles 23 a and 25 a are always constant, and the cleaning position displacement unit 70 (82 and 88) is set by the traveling speed changing unit 68. The displacement speed is controlled so that the relative speed between the traveling speed of the filter cloth belts 20 and 22 and the displacement speed of the cleaning position W in the cleaning devices 23 and 25 is always constant. And the discharge control part 64 carries out on-off control of discharge of cleaning water so that the discharge ON time of the cleaning water required for cleaning the predetermined area (cleaning range A) of the filter cloth belts 20 and 22 is always constant. Thereby, the usage-amount of the washing water required for washing | cleaning of a predetermined area can be maintained more reliably and constant, maintaining the washing | cleaning capability of the filter cloth belts 20 and 22.

  The cleaning devices 23 and 25 can clean a predetermined area (cleaning range A1) of the filter cloth belts 20 and 22 by discharging cleaning water while displacing the cleaning position W by the cleaning position displacement unit 70 (82 and 88). On the other hand, after the cleaning of the cleaning range A1 of the filter cloth belts 20 and 22 by displacing the cleaning position W is completed, the discharge control unit 64 has a predetermined area (cleaning) adjacent to the downstream side of the predetermined area where the cleaning is completed. The cleaning water discharge is controlled to be off until the start of cleaning for the range A2). Thereby, it is possible to reliably prevent wasting water while maintaining the cleaning ability of the filter cloth belts 20 and 22.

  Here, the sludge dewatering system 10 according to the present embodiment includes a concentrating device 12 and a dewatering device 14, and nozzles 23 a and 25 a are respectively provided so that the pair of filter cloth belts 20 and 22 of the dewatering device 14 can be washed. . Therefore, the traveling speed changing unit 68 can set the traveling speed of the filter cloth belt 16 in the concentrator 12 and can set the traveling speed of the filter cloth belts 20 and 22 in the dehydrator 14 according to the setting. The cleaning position displacement section 70 (82, 88) is a displacement speed of the cleaning position W by the nozzles 23a, 25a based on the traveling speed difference between the traveling speed of the filter cloth belt 16 and the traveling speed of the filter cloth belts 20, 22. The discharge control unit 64 may control the discharge of the cleaning water on and off based on the travel speed difference.

  That is, in the above-described configuration example, the traveling speed of the filter cloth belts 20 and 22 in the dehydrator 14 is used as a reference, the displacement speed of the cleaning position W is controlled according to the changed value, and the discharge of cleaning water is controlled on and off. It was supposed to be. On the other hand, the displacement speed of the cleaning position W is controlled based on the traveling speed difference between the traveling speed of the filter cloth belt 16 of the concentrating device 12 and the traveling speed of the dehydrating device 14, and the discharge of the cleaning water is controlled on and off. Also good. Then, on the basis of the cleaning performance of the filter cloth belt 16 in the concentrating device 12 and the usage amount of the cleaning water, the cleaning performance of the filter cloth belts 20 and 22 in the dehydrating device 14 is set so as to match the reference performance and the reference usage amount. The amount of washing water used can be set. Thereby, the washing | cleaning operation | movement according to the concentration capacity | capacitance of the concentration apparatus 12 and the dehydration capacity | capacitance of the spin-drying | dehydration apparatus 14 as a whole system is attained, and the use amount of washing water can be reduced more.

  For example, when the traveling speed of the filter cloth belt 16 of the concentrator 12 and the traveling speed of the filter cloth belts 20 and 22 of the dehydrator 14 are set to be the same, the cleaning position displacement unit 70 (82, 88) is the cleaning position. W is not displaced, and the discharge controller 64 always turns on the discharge of the cleaning water. On the other hand, when the traveling speed of the filter cloth belts 20 and 22 of the dehydrating apparatus 14 is set slower than the traveling speed of the filter cloth belt 16 of the concentrating device 12, the cleaning position displacement unit 70 (82, 88) travels as described above. The cleaning position W may be displaced according to the speed difference, and the discharge control unit 64 may perform on / off control of the discharge of the cleaning water according to the travel speed difference. As a result, it is possible to control the washing operation in consideration of the running speed difference between the running speed of the filter cloth belt 16 of the concentrating device 12 and the running speed of the filter cloth belts 20 and 22 of the dehydrating apparatus 14, and the washing water in the entire system can be controlled. The total amount of use can be reduced efficiently.

  Further, in the sludge dewatering system 10, as described above, the traveling speed of the filter cloth belts 20 and 22 of the subsequent dewatering device 14 is set and controlled slower than the traveling speed of the filter cloth belt 16 of the preceding concentration device 12. The sludge dewatering performance in the dewatering device 14 can be improved. Therefore, in this control, as shown in FIG. 1, the moisture content of the sludge concentrated by the concentration device 12 is measured by a moisture meter 59. For example, when the moisture content is lower than the reference value, it is introduced into the dehydration device 14. The water content can be further reduced by determining that the volume (cake amount) of the sludge is small and making the traveling speed of the filter cloth belts 20, 22 slower than the reference speed. On the other hand, when the moisture content of the sludge detected by the moisture meter 59 is higher than the reference value, it is determined that the volume of the sludge introduced into the dehydrator 14 is large, and the traveling speed of the filter cloth belts 20 and 22 is determined. By making it faster than the reference speed, it is possible to increase the amount of sludge that can be treated in the dewatering device 14 and prevent the occurrence of defective processing. That is, even if the properties of the sludge to be treated fluctuate, the dehydration process can be performed at an appropriate rotation speed according to the treatment capacity of the dehydration apparatus 14. And by performing the washing speed control based on the running speed control of the filter cloth belts 16, 20, and 22 and the running speed difference, the total amount of washing water used can be reduced while improving the dewatering efficiency of the entire system. Can do.

  As shown by a two-dot chain line in FIG. 1, in place of the moisture meter 59, the sludge falling from the concentrator 12 is temporarily stored in a container 61a, and a viscometer 61 for measuring the viscosity of the sludge in the container 61a is provided. It may be used. When the viscometer 61 is used, in the detection result, for example, when the sludge viscosity is lower than the reference value, the running speed of the filter cloth belts 20 and 22 is more than the reference speed because the moisture content is low. If the sludge viscosity is higher than the reference value, the traveling speed of the filter cloth belts 20 and 22 may be higher than the reference speed because it is almost synonymous with the high water content.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be freely changed without departing from the gist of the present invention.

  For example, in the above embodiment, in the sludge dewatering system 10 having the concentrating device 12 in the upper stage and the dewatering device 14 in the lower stage, the cleaning apparatuses 23 and 25 (80, 80) provided with the cleaning position displacement portions 70 (82, 88). 86) was used for cleaning the filter cloth belts 20 and 22 of the dehydrator 14. However, the cleaning devices 23 and 25 (80 and 86) provided with the cleaning position displacement portions 70 (82 and 88) in this way may be used for the concentration device 12 and, furthermore, have the same configuration as the concentration device 12. It may also be used for a concentrating device used alone or a dehydrating device used alone with the same configuration as the dehydrating device 14. In the example shown in FIG. 1, the cleaning devices 17 and 23 are cleaned by discharging cleaning water to the back surfaces of the filter cloth belts 16 and 20, and the cleaning device 25 is cleaning by discharging cleaning water to the surface of the filter cloth belt 22. Although it is configured, its arrangement can be changed as appropriate. That is, the filter cloth belts 16 and 20 may be cleaned from the front surface side with the cleaning devices 17 and 23, and the filter cloth belt 22 may be cleaned from the back surface side with the cleaning device 25. The belt 16, 20, 22 may be configured to be able to clean both surfaces.

  In the above embodiment, the cleaning position control unit 62 drives and controls the cleaning position displacement unit 70 and the like according to the traveling speed of the filter cloth belts 20 and 22 preset by the traveling speed setting unit 68. In contrast, a speedometer for measuring the traveling speed of the filter cloth belts 20 and 22 from the rotational speed of an inverter (not shown) provided in the lower drive unit 33 or detecting the actual traveling speed of the filter cloth belts 20 and 22 It is good also as a structure which provides detectors, such as an encoder, and operates the washing | cleaning position control part 62 and the washing | cleaning position displacement part 70 according to this real-time detection speed.

DESCRIPTION OF SYMBOLS 10 Sludge dehydration system 12 Concentrator 14 Dehydrator 15 Control device 16, 20, 22 Filter cloth belt 17, 23, 25, 80, 86 Washing device 17a, 23a, 25a Nozzle 18 Filtration part 24 Coagulation mixing tank 26 Primary dehydration roller 26 28 Pressurizing unit 29 Upper driving unit 30 Moving mechanism 33 Lower driving unit 50 Dehydrating unit 52 Squeezing unit 60 Belt drive control unit 62 Washing position control unit 64 Discharge control unit 68 Travel speed changing unit 70, 82, 88 Washing position displacement unit 74 Supply hose 76 Electromagnetic on-off valve

Claims (11)

A sludge dewatering system comprising an endless filter cloth belt that travels on a circular track and separates solid and liquid while conveying sludge, and a cleaning device that discharges cleaning water from a nozzle to clean the filter cloth belt. And
Traveling speed changing means for changing the traveling speed of the filter cloth belt;
Cleaning position displacing means for displacing the cleaning position of the filter cloth belt by the cleaning device in a direction along the longitudinal direction of the filter cloth belt at a displacement speed corresponding to the traveling speed of the filter cloth belt;
A discharge control means for controlling on / off the discharge of the washing water from the nozzle according to the traveling speed of the filter cloth belt;
A sludge dewatering system characterized by comprising: In the sludge dewatering system according to claim 1,
The cleaning device is set so that the discharge pressure and flow rate of cleaning water from the nozzle are always constant,
The cleaning position displacing means controls the displacement speed of the cleaning position so that the relative speed between the traveling speed of the filter cloth belt set by the traveling speed changing means and the displacement speed of the cleaning position is always constant. ,
The sludge dewatering system, wherein the discharge control means controls the discharge of the cleaning water so that the discharge time of the cleaning water required for cleaning the predetermined area of the filter cloth belt is always constant. In the sludge dewatering system according to claim 2,
The cleaning device is capable of cleaning a predetermined area of the filter cloth belt by discharging cleaning water while displacing the cleaning position by the cleaning position displacement means,
After the cleaning of the predetermined area of the filter cloth belt by displacing the cleaning position is completed, the discharge control means is in a period until the start of cleaning the predetermined area adjacent to the downstream side of the predetermined area where the cleaning is completed. A sludge dewatering system, wherein discharge of the washing water is controlled off. In the sludge dewatering system according to claim 2 or 3,
When the filter cloth belt is traveling at a reference traveling speed, the cleaning position displacement means does not displace the cleaning position, and the discharge control means always controls the discharge of the cleaning water to be on. Sludge dewatering system. In the sludge dewatering system according to any one of claims 2 to 4,
A concentrator that gravity concentrates while conveying sludge with an endless first filter cloth belt that travels on a circular track,
A dehydrator disposed downstream of the concentrator and dehydrating sludge under pressure between a pair of upper and lower second and third filter cloth belts;
The nozzles are respectively provided to be able to wash the second and third filter cloth belts of the dehydrator,
The travel speed changing means sets the travel speed of the first filter cloth belt in the concentrator, and sets the travel speed of the second and third filter cloth belts in the dehydrator according to the setting. Is possible,
The cleaning position displacement means controls the displacement speed of the cleaning position based on a traveling speed difference between a traveling speed of the first filter cloth belt and a traveling speed of the second and third filter cloth belts. ,
The sludge dewatering system, wherein the discharge control means performs on / off control of the discharge of the wash water based on the travel speed difference. In the sludge dewatering system according to claim 5,
The traveling speed of the second and third filter cloth belts is set equal to or slower than the traveling speed of the first filter cloth belt,
When the traveling speed of the first filter cloth belt and the traveling speed of the second and third filter cloth belts are set to be the same, the cleaning position displacement means does not displace the cleaning position, and The discharge control means always turns on the discharge of the cleaning water,
When the traveling speeds of the second and third filter cloth belts are set slower than the traveling speed of the first filter cloth belt, the cleaning position displacing means moves the cleaning position according to the traveling speed difference. The sludge dewatering system is characterized in that the discharge control means controls the discharge of the washing water on and off according to the travel speed difference. In the sludge dewatering system according to any one of claims 1 to 6,
The sludge dewatering system, wherein the cleaning position displacing means has a moving mechanism for moving the nozzle so that a predetermined area of the filter cloth belt can be cleaned. In the sludge dewatering system according to any one of claims 1 to 6,
A plurality of the nozzles are provided side by side along the steering direction of the filter cloth belt,
The sludge dewatering system characterized in that the cleaning position is displaced by sequentially turning on and off a plurality of nozzles by the discharge control means. Control of a sludge dewatering system comprising an endless filter cloth belt that travels on a circular track and separates solid and liquid while conveying sludge, and a cleaning device that discharges cleaning water from a nozzle to clean the filter cloth belt. A method,
The cleaning water is discharged from the nozzle while displacing the cleaning position of the filter cloth belt by the cleaning device in the direction along the longitudinal direction of the filter cloth belt at a displacement speed according to the traveling speed of the filter cloth belt. Control method of sludge dehydration system characterized by carrying out on-off control. In the control method of the sludge dewatering system according to claim 9,
The discharge pressure and the discharge amount per unit time from the nozzle in the cleaning device are always set to be constant,
Controlling the displacement speed of the washing position so that the relative speed between the traveling speed of the filter cloth belt and the displacement speed of the washing position is always constant,
A control method for a sludge dewatering system, wherein discharge of the cleaning water is on / off controlled so that a discharge on time of the cleaning water required for cleaning a predetermined area of the filter cloth belt is always constant. In the control method of the sludge dewatering system according to claim 9 or 10,
The sludge dewatering system is a concentration device that concentrates gravity while conveying sludge with an endless first filter cloth belt that runs on a circular track,
A dehydrator disposed downstream of the concentrator and dehydrating sludge under pressure between a pair of upper and lower second and third filter cloth belts;
The nozzles are respectively provided to be able to wash the second and third filter cloth belts of the dehydrator,
Controlling the displacement speed of the cleaning position based on the traveling speed difference between the traveling speed of the first filter cloth belt and the traveling speed of the second and third filter cloth belts;
A control method for a sludge dewatering system, wherein on-off control of discharge of the washing water is performed based on the difference in traveling speed.

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