JP2008188601A - Method for fixedly controlling flow rate in multiscrew press, and device for fixedly controlling flow - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for fixedly controlling the flow in multiscrew presses by which varied feed sludge can be controlled into a fixed feed pressure and a uniform flow. <P>SOLUTION: In multiscrew presses, the feed pressure (PS) of a slurry feed tube (32) varying in accordance with the change in the properties of sludge is detected, and the rotating frequencies (Ma, Mb) of external cylinder screens (2a, 2b, ...) in a plurality of lines are controlled with the same rotating frequency, so as to be a previously set standard pressure (PO). Further, the flows (Q1, Q2) of flocculated slurry in respective branched feed pipes (3a, 3b, ...) varying in accordance with the conditions of the clogging of screw presses (1a, 1b) are detected, and the rotating frequencies (Na, Nb) of screw shafts (4a, 4b) in a plurality of lines are controlled with individual rotating frequencies, so as to be homogenous flow. In this way, the feed pressure (PS) and the flows (Q1, Q2) of flocculated slurry are made stable, and the water content in a dewatered cake can be retained to the uniform optimum value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a screw press that adds a flocculant to sewage mixed raw sludge, sewage digested sludge, activated surplus sludge, etc., and performs solid-liquid separation of the agglomerated slurry while rotating the outer cylinder screen and the screw shaft at a differential speed, in particular. The present invention relates to a constant flow rate control method and a constant flow rate control device for a multiple screw press that simultaneously controls a plurality of screw presses.

Conventionally, sludge containing difficult-to-filter organic substances is subjected to solid-liquid separation by adding flocculant to form a floc of suspended solids to reduce the moisture content of the dehydrated cake. As a device for concentrating and dewatering this difficult-to-filter sludge, a screw press that concentrates and dewaters while rotating the screw shaft built in the outer cylinder screen to regenerate the filtration surface that is easily clogged is well known. Yes. Also, as described in Patent Document 1, a screw press that prevents an overload by providing a load detection device on a rotatable outer cylinder screen drive device and decelerating the outer cylinder by load detection. It is known. In addition, the filtration device provided with a screw rotatably inside the filter body is provided with a supply pressure detection means, a screw torque detection means, and a screw rotation speed control means. A control device that controls the number of rotations of the screw to keep the water content of the treated product constant is also known as described in Patent Document 2.
Japanese Patent No. 2500403 (paragraph numbers 0007 to 0009, FIG. 1) Japanese Patent No. 3544070 (Claim 4, FIG. 1)

  Conventional screw presses can control sludge with low viscosity and good filterability by controlling the rotational speed of the screw shaft to prevent overload and obtain a cake with a uniform moisture content. For filterable sludge, if the volume of the filtration chamber is reduced and squeezed and dewatered, the filtration surface of the outer cylinder screen is clogged at an early stage. Or if it squeezes rapidly, sludge will be discharged | emitted from an outer cylinder screen with a filtrate, and there exists a possibility that a filtrate may be suspended. In addition, in devices that detect the sludge concentration and supply volume and control the moisture content and torque of the dewatered cake, there are always changes in the supply sludge volume and sludge concentration, and rotation on the screw shaft and outer cylinder screen. The torque fluctuated and it was difficult to make the water content of the dehydrated cake uniform. In this invention, the agglomerated slurry supplied to a plurality of screw presses from one agglomeration mixing tank controls the supply pressure and the supply flow rate that fluctuate in response to changes in properties, and controls the rotation speed of the outer cylinder screen and the screw shaft. Provided are a constant flow rate control method and a constant flow rate control device for a multiple screw press that control a constant supply pressure and a uniform flow rate of agglomerated slurry.

  The constant flow rate control method of the multiple screw press according to the present invention connects a plurality of branch supply pipes branched from the slurry supply pipe to a plurality of rows of screw presses, while rotating the outer cylinder screen and the screw shaft at a different speed, In a plurality of screw presses that perform solid-liquid separation of the agglomerated slurry, the supply pressure of the slurry supply pipe that fluctuates according to the sludge properties is detected, and the plurality of rows of outer cylinder screens are set so as to have a preset reference pressure. Controls the number of rotations at the same number of rotations, detects the flow rate of each branch supply pipe that fluctuates due to clogging of the screw press, and individually controls the number of rotations of the screw shafts in multiple rows so that the flow rate is uniform. Supplying multiple rows of screw presses in response to unbalanced supply of undiluted solutions such as sludge changes and screw press clogging The supply flow rate is stabilized, to prevent variations in the water content of dehydrated cake, it is possible to maintain the moisture content to a uniform optimum.

  Another method of controlling the flow rate according to another invention of the multi-series screw press is to detect the supply pressure of the slurry supply pipe which fluctuates according to the sludge properties, and to arrange the screw shafts in a plurality of rows so that the reference pressure is set in advance. The number of rotations of the outer tube screens in multiple rows is individually controlled so that the flow rate of each branch supply pipe that fluctuates due to clogging of the screw press is detected and the flow rate is equalized. The water content of the dewatered cake can be maintained uniformly by controlling the supply pressure and the supply flow rate of the screw press uniformly.

  A constant flow rate control device of a multiple screw press for carrying out the constant flow rate control method according to the present invention comprises a filtration chamber formed by a screw shaft around which an outer cylinder screen and screw blades are wound, and the outer cylinder is mounted on the outer cylinder screen. In a screw press that disposes agglomerated slurry by solid-liquid separation while rotating the outer cylinder screen and the screw shaft at a differential speed while arranging the screw drive device on the drive machine and the screw shaft, a plurality of branched supplies branched from the slurry supply pipe Connect the pipes to multiple rows of screw presses, and connect the pressure gauge provided on the slurry supply pipe to the outer cylinder drive via the pressure controller, so that the supply pressure of the agglomerated slurry is constant. The number of revolutions is controlled at the same number of revolutions, and the slurry flow meters installed in each branch supply pipe are connected to the screw drive machine via the flow rate controller. The rotation speed of the screw shaft is individually controlled so that the flow rate of the coagulated slurry supplied to the screw press is equal to the flow rate. The supply pressure of the coagulated slurry depends on the change in the sludge properties and the clogging status of the screw press. Since the supply flow rate can be made uniform, the moisture content of the dewatered cake can be made uniform and the moisture content can be maintained at the optimum value. And there is no possibility that dehydrated sludge is discharged from the outer cylinder screen together with the filtrate.

  In another invention of the multiple flow screw press, the constant flow rate control device connects the pressure gauge provided in the slurry supply pipe to the screw drive through the pressure controller, and supplies the aggregated slurry according to the change in the sludge properties. While controlling the number of rotations of the screw shaft at the same number of rotations so that the pressure is constant, the slurry flow meters provided in the respective branch supply pipes are connected to the outer cylinder driving machine via the flow rate controller, The rotational speed of the outer cylinder screen may be individually controlled so that the flow rate of the agglomerated slurry is equal to the clogging situation of the screw press. Can be maintained.

  A coagulation mixing tank installed at the front stage of the screw press is connected to a stock solution supply pipe provided with a constant flow stock solution supply pump, a concentration meter and a stock solution flow meter, and a chemical solution supply pipe provided with a polymer supply pump and a chemical flow meter. Is connected to the stock solution supply pipe, and a solid proportional injection controller that controls the rotation speed of the polymer supply pump according to the amount of solid matter in the sludge of the stock solution supply pipe is arranged, and the agglomeration of the preset drug injection rate Since the agent is added and the sludge is press-fitted into the flocculation mixing tank, the amount of chemical used can be reduced by adjusting the flocculating agent.

  The constant flow rate control method and the constant flow rate control device of the multiple screw press according to the present invention are configured as described above, and in response to fluctuations in the supply pressure and supply amount of the agglomerated slurry due to changes in the sludge properties, Since the three parameters of the pouring rate, the outer cylinder screen, and the rotational speed of the screw shaft are controlled in combination, the moisture content of the dewatered cakes of a plurality of screw presses can be made uniform. In response to fluctuations in the supply pressure and supply amount of the agglomerated slurry due to changes in the sludge properties, the rotation speed of the outer cylinder screen or screw shaft is simultaneously controlled to maintain the supply pressure to the screw press constant. Depending on the clogging situation of the press, the rotation speed of the screw shaft or the outer cylinder screen is individually controlled to maintain the stock solution supply amount at a uniform flow rate, so that the moisture content of the dewatered cake can be maintained at a uniform optimum value. And the amount of chemicals used can be reduced. Since the dehydrated cake is stabilized, the management of the treatment process after dehydration becomes easy.

  A constant flow rate control method and a constant flow rate control device for a multiple screw press according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a partially longitudinal side view of a screw press used in a constant flow rate control device. The screw press 1 includes a screw shaft 4 in which a screw blade 3 is wound around an outer cylinder screen 2 having a filtration surface on the periphery. The screw shaft 4 is enlarged from the sludge supply side to the cake discharge side, and the filtration chamber 5 between the outer cylinder screen 2 and the screw shaft 4 is reduced from the supply side to the discharge side. FIG. 2 is an enlarged view of the supply side of the screw press, in which a sprocket 7 is fitted on the inlet flange 6 fitted on the supply side of the outer cylinder screen 2 and the outer cylinder drive capable of forward and reverse rotation mounted on the frame 8. It is linked to the machine 9. A supply path 11 for agglomerated slurry is provided in the screw shaft 4, a supply hole 11 a is opened at the start end of the filtration chamber 5, and a supply pipe 10 is connected to the screw shaft 4. FIG. 3 is an enlarged view of the discharge side of the screw press. A rotary plate 12 connected to the discharge side of the outer cylinder screen 2 is supported on a frame 13, and a screw shaft 4 provided in the outer cylinder screen 2 is screwed on the screw shaft 4. A drive shaft 14 is connected. A back pressure adjusting presser 15 provided at the outlet 5 a of the filtration chamber 5 is slidably supported on a moving shaft 16 disposed on the frame 13. As shown in FIG. 1, the screw drive shaft 14 connected to the screw shaft 4 is pivotally supported on a bearing 19 provided on a frame 18 of the frame 13. A sprocket 20 is fitted on the screw drive shaft 14 and linked to a screw drive machine 21 placed on the frame 13.

  As shown in FIG. 1, the external cylinder drive 9 of the external cylinder screen 2 and the screw drive 21 of the screw shaft 4 that are individually arranged are operated to rotate the external cylinder screen 2 and the screw shaft 4 in the reverse direction in the differential direction. Then, the agglomerated slurry is supplied from the supply path 11 of the screw shaft 4 to the filtration chamber 5, and the filtrate is separated from the outer cylinder screen 2 while the agglomerated slurry is transferred by the screw blades 3. The opening amount of the discharge port 5a of the filtration chamber 5 is adjusted by the presser 15, and solid-liquid separation is promoted while applying back pressure to the filtration chamber 5, thereby discharging the dehydrated cake. By rotating the outer cylinder screen 2 and the screw shaft 4 in the reverse direction, the rotational speed of the screw blades 3 is relatively increased, and the number of sliding contact of the filtration surface of the outer cylinder screen 2 is increased. A cleaning tube 22 is disposed along the outer cylinder screen 2, and a filtrate trough 23 is disposed below the outer cylinder screen 2. Reference numeral 24 denotes a cake receiving tank for the dehydrated cake disposed at the end of the screw press 1.

  FIG. 4 is a schematic configuration diagram of a constant flow rate control device of a multiple screw press, in which a constant flow stock solution supply pump SP, a concentration meter D, and a stock solution flow meter are connected to a stock solution supply pipe 26 for extracting sludge from a sludge storage tank 25. F is disposed, and the concentration of sludge and the raw sludge flow rate Qs are measured. The chemical solution supply pipe 28 is connected to the polymer dissolution tank 27 provided in the sludge storage tank 25, and the flow rate of the polymer supply pump PP for supplying the flocculant to the sludge to the chemical liquid supply pipe 28 and the addition amount of the flocculant A chemical flow meter Fp for measuring is disposed. The chemical solution supply pipe 28 is connected to the rear of the stock solution supply pipe 26 in which the stock solution flowmeter F is disposed. A concentration meter D and a stock solution flow meter F arranged in the stock solution supply pipe 26 and a chemical solution flow meter Fp arranged in the chemical solution supply pipe 28 are connected to the solid proportional injection controller 29, and the detected stock solution concentration of sludge is detected. And the detection signal of the raw sludge flow rate Qs is sent to the solid matter proportional injection controller 29 to calculate the solid matter amount of the raw sludge flow rate Qs to be extracted from the sludge storage tank 25 at a constant flow rate. The detection signal is transmitted to the solid proportional injection controller 29, and compared with the supply amount of the polymer flocculant to be added according to the solid amount of sludge set in advance, the predetermined flocculant addition rate is obtained. As described above, the rotation speed PPQ of the polymer supply pump PP is controlled to supply the polymer flow rate Qp with an appropriate addition rate to the raw sludge flow rate Qs of the stock solution supply pipe 26.

As shown in FIG. 4, the rear end of the stock solution supply pipe 26 is connected to the tank bottom of the sealed coagulation mixing tank 30, and sludge to which the polymer flocculant is added is pressed into the coagulation mixing tank 30 from the bottom, Agitation slurry is produced by stirring and mixing with the agitator 31. A slurry supply pipe 32 for extracting the agglomerated slurry with tank pressure is connected to the agglomeration mixing tank 30, and a plurality of branched supply pipes 33a and 33b branched from the slurry supply pipe 32 are connected to the screw presses 1a and 1b, respectively. Yes, the agglomerated slurry is supplied to the supply pipe 10 of the screw press 1 shown in FIG. In the embodiment of the present invention, two screw presses 1a and 1b are installed, but they can be added to a plurality of rows as necessary.

  As shown in FIG. 4, a pressure gauge PSo is disposed in a slurry supply pipe 32 for extracting the aggregated slurry from the aggregation mixing tank 30, and a pressure controller 35 for transmitting a supply pressure detection signal is connected to the pressure gauge PSo. It is. Comparing the supply pressure PS of the agglomerated slurry received by the pressure controller 35 with a preset reference pressure PO, and transmitting a command signal for the number of rotations to be corrected to the outer cylinder drivers 9a and 9b, and the properties of the sludge The rotational speeds Ma and Mb of the plurality of outer cylinder screens 2a and 2b are simultaneously controlled at the same rotational speed so that the supply pressure PS that fluctuates in response to the change becomes the reference pressure PO. Slurry flow meters F1 and F2 are arranged in branch supply pipes 33a and 33b branched from the slurry supply pipe 32, and flow rate controllers 36a and 36b for transmitting detection signals of the flow rates Q1 and Q2 of the agglomerated slurry are respectively provided. It is individually connected to the slurry flow meters F1 and F2. The rotational speed command Qa, Q2 received by the flow rate controllers 36a, 36b is compared with the preset uniform supply flow rate {(Qs + Qp) / the number of branch supply pipes} and the rotational speed command to be corrected. Signals are individually transmitted to the screw drivers 21a and 21b, and the rotational speeds Na and Nb of the screw shafts 4a and 4b are individually controlled according to the clogging state of the screw presses 1a and 1b, and the branch supply pipes 33a and 33b are controlled. The supply amount of the agglomerated slurry is adjusted to a uniform flow rate (Q1≈Q2). The moisture content of the dehydrated cake can be kept constant, and the amount of chemicals used can be reduced in response to changes in sludge properties. Since the dehydrated cake is stabilized, the management of the treatment process after dehydration becomes easy.

FIG. 5 is a flowchart of a constant flow rate control method for a multiple screw press,
1: The operation of the screw presses 1a and 1b is started and the outer cylinder screens 2a and 2b and the screw shafts 4a and 4b are rotated at a differential speed.
2: A predetermined polymer flow rate Qp is added to the fixed raw sludge flow rate Qs (Q = Qs + Qp), and the mixture is stirred and mixed in the coagulation mixing tank 30, and the coagulated slurry is supplied to the screw presses 1a and 1b.
3: The screw presses 1a and 1b operate the screw drivers 21a and 21b at initial rotation speeds Na and Nb.
4: The supply pressure PS of the aggregated slurry in the slurry supply pipe 32 is measured by the pressure gauge PSo at every set time, and the detection signal is transmitted to the pressure controller 35.
5: The pressure controller 35 compares the supply pressure PS of the agglomerated slurry with a preset reference pressure PO.
6: When the supply pressure PS of the agglomerated slurry is larger than the reference pressure PO (PS> PO), a correction command signal is transmitted to the outer cylinder drivers 9a and 9b, and the rotational speed Ma of the outer cylinder drivers 9a and 9b Mb is simultaneously increased to the same number of rotations to maintain the reference pressure (PS = PO).
7: When the supply pressure PS of the agglomerated slurry is smaller than the reference pressure PO (PS <PO), the rotational speeds Ma and Mb of the outer cylinder drivers 9a and 9b are decreased.
The outer cylinder screens 2a and 2b are controlled at the same rotational speed so that the supply pressure PS that fluctuates in response to changes in the sludge properties becomes the reference pressure PO.
8: Next, the flow rates Q1 and Q2 of the agglomerated slurry in the respective branch supply pipes 33a and 33b are measured, and the detection signals are transmitted to the individual flow rate controllers 36a and 36b.
9: Comparing and calculating the flow rates Q1 and Q2 of the agglomerated slurry in the respective branch supply pipes 33a and 33b and a preset flow rate set value δ.
10: When the flow rates Q1 and Q2 of the agglomerated slurry are smaller than the set value δ {(Q1-Q / 2) ≦ −δ or (Q2−Q / 2) ≦ −δ}, the screw shafts 4a and 4b Command signals for individually increasing the rotation speeds Na and Nb are transmitted to the screw drivers 21a and 21b.
11: When the flow rates Q1 and Q2 of the agglomerated slurry are larger than the set value {(Q1-Q / 2)> δ or (Q2-Q / 2)> δ}, the rotation of the screw drive shafts 21a and 21b The numbers Na and Nb are decreased individually.
The flow rates Q1 and Q2 of the agglomerated slurry are always within the allowable range of the set value {−δ ≦ (Q1−Q / 2) ≦ δ or −δ ≦ (Q2−Q / 2) ≦ δ}. The rotation speeds Na and Nb of the screw shafts 4a and 4b are controlled in accordance with the clogging state of the screw presses 1a and 1b.

  FIG. 6 is a schematic configuration diagram of another embodiment of a constant flow rate control device for a multiple screw press, in which a pressure gauge PSo disposed in a slurry supply pipe 32 is connected to a screw driver 21 c via a pressure controller 38. Connected. The supply pressure of the agglomerated slurry is received by the pressure controller 38, compared with a preset reference pressure, and a command signal for the rotational speed to be corrected is transmitted to the screw driver 21c. One screw drive 21c is interlocked with the two screw shafts 4a and 4b, and the plurality of screw shafts 4a and 4b are set so that the supply pressure that fluctuates in response to changes in sludge properties becomes the reference pressure. Are simultaneously controlled at the same rotational speed. Slurry flow meters F1 and F2 arranged in the branch supply pipes 33a and 33b for the agglomerated slurry are connected to the outer cylinder drivers 9a and 9b via the flow controllers 39a and 39b. The flow controllers 39a and 39b that have received the detection signals of the flow rates Q1 and Q2 of the aggregated slurry perform a comparison operation with a preset uniform supply flow rate {(Qs + Qp) / the number of branch supply pipes} and correct the rotation. Command signals individually to the outer cylinder driving machines 9a and 9b, and the number of rotations of the outer cylinder screens 2a and 2b is controlled in accordance with the clogging situation of the screw presses 1a and 1b, so that the stock solution supply amount is equalized ( Adjust to Q1≈Q2). Even in the multiple flow screw press constant control device of the present invention, the moisture content of the dewatered cake can be kept constant, and the amount of chemicals used can be reduced in response to fluctuations in sludge properties. And since a dewatering cake is stabilized, management of the processing process after dehydration also becomes easy.

FIG. 7 is a flowchart of another embodiment of the constant flow rate control method of the multiple screw press,
1: Start the operation of the screw press 1a, 1b,
2: Aggregated slurry obtained by adding a predetermined polymer flow rate Qp to a fixed raw sludge flow rate Qs is supplied to the screw presses 1a and 1b.
3: The screw presses 1a and 1b operate the screw driver 21c at an initial rotation speed Nc, and drive the screw shafts 4a and 4b at the same rotation speed.
4: The supply pressure PS of the agglomerated slurry in the slurry supply pipe 32 is measured every set time, and the detection signal is transmitted to the pressure controller 38.
5: The pressure controller 38 compares the supply pressure PS of the agglomerated slurry with a preset reference pressure PO.
6: When the supply pressure PS of the agglomerated slurry is larger than the reference pressure PO (PS> PO), a correction command signal is transmitted to the screw driver 21c, and the screw shafts 4a and 4b are simultaneously increased to the same rotational speed. Adjust to the reference pressure (PS = PO).
7: When the supply pressure PS of the agglomerated slurry is smaller than the reference pressure PO (PS <PO), the rotational speed Nc of the screw driver 21c is decreased.
The screw shafts 4a and 4b are controlled at the same rotational speed so that the supply pressure PS that fluctuates in response to changes in the sludge properties becomes the reference pressure PO.
8: Next, the flow rates Q1 and Q2 of the agglomerated slurry in the respective branch supply pipes 33a and 33b are measured, and the detection signals are transmitted to the individual flow rate controllers 39a and 39b.
9: Comparing and calculating the flow rates Q1 and Q2 of the agglomerated slurry in the respective branch supply pipes 33a and 33b and a preset flow rate set value δ.
10: When the flow rates Q1 and Q2 of the agglomerated slurry are smaller than the set value δ {(Q1-Q / 2) ≦ −δ or (Q2-Q) / 2 ≦ −δ), the outer cylinder screen 2a, Command signals for increasing the rotation speeds Ma and Mb of 2b are individually transmitted to the respective outer cylinder driving machines 9a and 9b.
11: When the flow rates Q1 and Q2 of the agglomerated slurry are larger than the set value {(Q1-Q / 2)> δ or (Q2-Q / 2)> δ}, the outer cylinder screens 2a and 2b are rotated. The flow rates Q1 and Q2 of the agglomerated slurry for individually decreasing the numbers Ma and Mb are always within the allowable range of the set value {−δ ≦ (Q1−Q / 2) ≦ δ or −δ ≦ (Q2−Q / 2). ) ≦ δ}, the rotational speeds Ma and Mb of the outer cylinder screens 2a and 2b are individually controlled according to the clogging state of the screw presses 1a and 1b.

  The constant flow rate control method and the constant flow rate control device for the multiple screw press according to the present invention are capable of adjusting the chemical injection rate, the outer cylinder screen, and the screw shaft rotation speed in response to fluctuations in the supply pressure and supply amount of the agglomerated slurry. Since the three parameters are combined and controlled, the water content of the dewatered cakes of a plurality of rows of screw presses can be made uniform. That is, the rotational speed of the outer cylinder screen or screw shaft is simultaneously controlled so that the supply pressure to the screw press becomes constant in response to changes in the sludge properties, and the moisture content of the dewatered cake is reduced by clogging of the screw press. In order to prevent the difference from occurring, it is possible to equalize the supply pressure and supply amount of sludge by individually controlling the rotation speed of the screw shaft or the outer cylinder screen. And according to the fluctuation | variation of sludge property, the moisture content of a dewatering cake can be kept constant, and chemical usage-amount can also be reduced. Since the dehydrated cake is stabilized, the management of the treatment process after dehydration becomes easy. Therefore, since a plurality of screw presses can be controlled simultaneously, the screw press is suitable for a treatment plant that requires a large volume of treatment such as sewage mixed raw sludge, sewage digested sludge, activated surplus sludge and the like.

It is a partial longitudinal cross-sectional side view of the screw press used for the multiple flow type constant flow control apparatus which concerns on this invention. Similarly, it is an enlarged view of the supply side of the screw press. Similarly, it is an enlarged view of the discharge side of the screw press. It is a schematic block diagram of the flow volume constant control apparatus of a multiple continuous screw press. Similarly, it is a flowchart of a flow rate constant control method. Similarly, it is a schematic block diagram of the other Example of the constant flow control apparatus. Similarly, it is a flowchart of the other Example of the constant flow control method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Screw press 2, 2a, 2b Outer cylinder screen 3 Screw blade 4a, 4b Screw shaft 5 Filtration chamber 9, 9a, 9b Outer cylinder drive machine 21 Screw drive machine 26 Stock solution supply pipe SP Stock solution supply pump D Concentration meter F Stock solution flow meter 31 Chemical solution supply pipe PP Polymer supply pump FP Chemical solution flow meter 29 Solid matter proportional injection controller 30 Coagulation mixing tank 32 Slurry supply tube 33a, 33b Branch supply tube PSo Pressure gauge 35, 38 Pressure controller F1, F2 Slurry flow meter 36a, 36b, 39a, 39b Flow rate controller Na, Nb, Nc Number of rotations of screw shaft Ma, Mb Number of rotations of outer cylinder screen Q1, Q2 Flow rate PO Reference pressure PPQ Number of rotations of polymer supply pump PS Supply pressure

Claims (5)

  A plurality of screw presses (1...) Are connected to a plurality of branch supply pipes (33a, 33b...) Branched from the slurry supply pipe (32) of the agglomerated slurry, and an outer cylinder screen (2...). And the screw shaft (4...) Are rotated at a differential speed, and the supply pressure (PS) of the slurry supply pipe (32) that fluctuates according to the sludge properties is detected in a plurality of screw presses that perform solid-liquid separation. The rotational speeds (Ma, Mb,...) Of the plurality of rows of outer cylinder screens (2a, 2b,...) Are controlled at the same rotational speed so as to have a preset reference pressure (PO). The flow rate (Q1, Q2...) Of each branch supply pipe (33a, 33b...) That fluctuates due to clogging of the screw press (1a, 1b...) Is detected, and the uniform flow rate (Q1≈Q2). Multiple rows so that ≒ ...) Constant flow rate control of multiple screw presses, characterized in that the rotational speed (Na, Nb,...) Of the screw shafts (4a, 4b,...) Is individually controlled to make the water content of the dewatered cake uniform. Method.   A plurality of rows of screw shafts (4a, 4b,...) Are detected so that the supply pressure (PS) of the slurry supply pipe (32), which fluctuates according to the sludge properties, is detected and set to a preset reference pressure (PO). .) (Nc...) Is controlled at the same rotation number, and each branch supply pipe (33a, 33b...) Fluctuates due to clogging of the screw press (1a, 1b...). The flow rate (Q1, Q2,...) Is detected and the rotation speeds (Ma, Mb,...) Of the plurality of rows of outer cylinder screens (2a, 2b. The water content of the dewatered cake is made uniform, and the flow rate constant control method for the multiple screw press according to claim 1.   A filtration chamber (5) is formed by a screw shaft (4) around which an outer cylinder screen (2) and screw blades (3) are wound, and an outer cylinder driving machine (9) and a screw shaft (4) are formed on the outer cylinder screen (2). In a screw press that disposes the agglomerated slurry by solid-liquid separation while rotating the outer cylinder screen (2) and the screw shaft (4) at a differential speed by disposing a screw driver (21) to the slurry supply pipe (32). ) Are connected to a plurality of screw presses (1a, 1b...), And a pressure gauge (PSo) provided on the slurry supply pipe (32) is connected. The outer cylinder screen is connected to the outer cylinder driver (9a, 9b, ...) via the pressure controller (35) so that the supply pressure (PS) of the agglomerated slurry is constant according to the change in the sludge properties. (2a, 2b ...) rotation speed Ma, Mb... Are controlled at the same rotational speed, and slurry flow meters (F1, F2...) Provided in the respective branch supply pipes (33a, 33b. 36a, 36b...) Are connected to the screw drives (21a, 21b...), And the flow rate (Q1, Q2) of the agglomerated slurry according to the clogging situation of the screw press (1a, 1b...). ..)) Are controlled individually so that the screw shafts (4a, 4b...) Have a uniform flow rate, and the moisture content of the dehydrated cake is made uniform. A constant flow rate control device for multiple screw presses.   The pressure gauge (PSo) provided in the slurry supply pipe (32) is connected to the screw driver (21c) via the pressure controller (38), and the supply pressure (PS ) Is controlled so that the rotation speed (Nc...) Of the screw shafts (4a, 4b...) Is the same, and the branch supply pipes (33a, 33b. The slurry flow meters (F1, F2,...) Provided in the are connected to the outer cylinder driving machines (9a, 9b) via the flow controllers (39a, 39b...), And the screw presses (1a, 1b,. The rotation speed (Ma, Mb,...) Of the outer cylinder screen (2a, 2b,...) So that the flow rate (Q1, Q2,.・) To control the water content of the dehydrated cake evenly. Constant flow rate control device of the plurality communication type screw press according to claim 3, characterized in Rukoto.   A stock solution supply pipe (26) provided with a constant flow stock solution supply pump (SP), a concentration meter (D), and a stock solution flow meter (F) in an agglomeration mixing tank (30) installed in the preceding stage of the screw press (1). And a chemical supply pipe (28) provided with a polymer supply pump (PP) and a chemical flowmeter (Fp) are connected to the raw liquid supply pipe (26), and the amount of sludge solids in the raw liquid supply pipe (26) The solid proportional injection controller (29) for controlling the rotation speed (PPQ) of the polymer supply pump (PP) according to the above is disposed. A constant flow rate control device for multiple screw presses.

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