JP2018122216A - Sludge dewatering device and control method and program of sludge dewatering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of obtaining information regarding the water content of a dewatered cake in real time with simple device configuration in a centrifugal separation type sludge dewatering device.SOLUTION: A centrifugal separation type sludge dewatering device comprises: a sludge discharge port 112 discharging sludge after dewatering; a rotation cylinder 110 centrifuging and dewatering the sludge inside by being rotated around a shaft; a housing 130 preventing the sludge after dewatering discharged from the sludge discharge port 112 from scattering; and a sensor 161 detecting physical quantity regarding shock when the sludge after dewatering discharged from the sludge discharge port 112 collides with the housing 130.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for dewatering sludge and a control method thereof, and more specifically to an apparatus for dewatering sludge by a centrifugal separation method.

  Conventionally, sludge generated in the treatment process of a sewage treatment facility or the like is dehydrated to reduce the water content, and then disposed of by incineration or the like. There are various types of dehydration devices used for such dehydration treatment, and it is usual to increase the efficiency of dehydration by injecting flocculant suitable for each dehydration device into the sludge before treatment. Has been done.

  By the way, about the sludge after dehydration processing (henceforth dehydrated cake), if the moisture content is low, not only the cost (fuel cost) at the time of incineration is reduced, but also the cost at the time of storage and transportation is reduced. be able to. Also, from the viewpoint of environmental protection, when the water content of the sludge to be discarded is low, a public subsidy may be issued. From the viewpoint of cost after treatment, the water content of the dehydrated cake is lower. Is desirable.

  On the other hand, in order to reduce the moisture content of the dehydrated cake, it is necessary to increase the amount of the flocculant injected or lengthen the dehydration time. Therefore, the lower the moisture content of the dehydrated cake, the lower the operating cost of the device. It will be high. If the moisture content is too low, depending on the type of the dehydrating device, there is a problem that the dehydrated cake is pressed inside and clogged.

  For this reason, it is desirable to adjust the moisture content of the dehydrated cake so as not to cause clogging inside the apparatus and to be the most cost-effective value in view of the cost during operation of the apparatus and the cost after the dehydration process. . However, the moisture content of the dewatered cake varies from time to time depending on the quality of the sludge supplied, various operating conditions of the dewatering device, etc. In order to maintain the moisture content of the dewatered cake at an appropriate (range) value, It is necessary to frequently measure the moisture content and change the operating conditions of the apparatus based on the result.

  From the above, it is desirable that the moisture content of the dehydrated cake can be measured in real time so that the operating conditions of the apparatus can be changed immediately when the moisture content of the dehydrated cake deviates from an appropriate value.

  For this reason, methods for measuring the moisture content of a dehydrated cake in real time, such as a method for evaluating the weight of a dehydrated cake every fixed time and a method for evaluating a change in color tone of dehydrated sludge, have been proposed so far. Yes. However, since the dewatering cake discharge time varies and the same amount of dehydrated cake cannot always be measured every fixed time, the method of evaluating the weight has a problem in the accuracy of the measurement result. In addition, in facilities that treat multiple types of sludge, the properties including color differ depending on the type of sludge, so it is difficult to treat various types of sludge with the measurement method that evaluates the color change of the sludge. .

  On the other hand, for example, a method of indirectly measuring the moisture content from the resultant force generated when the dehydrated cake is discharged from the apparatus using a load cell (Patent Document 1), color difference information and infrared moisture of a plurality of types of dehydrated cake in advance A method of storing calibration curve information for the measured value of the meter and measuring the moisture content with an infrared moisture meter based on these is disclosed (Patent Document 2).

JP2013-205309A Japanese Patent Laid-Open No. 6-229918

  However, the method described in Patent Document 1 has a problem that it cannot be applied to a centrifugal sludge dewatering device that discharges while dewatered cake is scattered. Further, the method described in Patent Document 2 has a problem that a lot of examination information must be accumulated in advance and a calibration curve must be set.

  In view of the situation as described above, the present invention provides a technology capable of acquiring information about the moisture content of a dewatered cake in real time with a simple device configuration in a centrifugal sludge dewatering device. Objective.

  In order to achieve the above object, the present invention adopts the following configuration.

  A centrifugal sludge dewatering device, comprising a sludge discharge port for discharging sludge after dewatering, a rotating cylinder for centrifugally separating and dewatering sludge by rotating around an axis, and the sludge discharge A housing for preventing the sludge after dewatering discharged from the outlet from scattering, and a sensor for detecting a physical quantity relating to an impact when the sludge after dewatering discharged from the sludge discharge port collides with the housing, Having sludge dewatering equipment.

  Since the dehydrated cake has different properties such as weight, hardness, and viscosity depending on its moisture content, the sound pressure level when the dehydrated cake collides with the inner wall of the casing after being discharged from the sludge discharge port, the casing Physical quantities such as body strain change due to differences in properties depending on the moisture content of the dehydrated cake. For this reason, the information about the moisture content of the dewatered cake can be acquired in real time by constantly measuring the physical quantity related to the impact at the time of the collision using the sensor.

  In addition, the sludge dewatering device may further include a determination unit that determines whether the moisture content of the sludge after dewatering exceeds a predetermined allowable value based on the physical quantity detected by the sensor. .

  The moisture content of the dehydrated cake is preferably as low as possible, but in view of the cost for reducing the moisture content, it is generally acceptable that the moisture content is below a predetermined target value. In such a case, It is only necessary to determine whether or not the moisture content of the dehydrated cake exceeds the predetermined value. In addition, by including the determination unit as described above, it is possible to obtain information on whether or not the moisture content of the dehydrated cake exceeds the allowable value without knowing the correlation between the physical quantity and the moisture content of the dehydrated cake.

  Further, the sludge dewatering device is disposed inside the rotating cylinder, and conveys sludge to the sludge discharge port by rotating in the same direction as the rotating cylinder at a rotation speed different from the rotation speed of the rotating cylinder. The difference between the rotational speed of the rotary cylinder and the screw conveyor so that the moisture content of the sludge after dehydration is a value within a predetermined target range based on the physical quantity detected by the sensor and the sensor. At least one of the operating conditions of the amount of the chemical solution injected into the sludge, the type of the chemical solution injected into the sludge, the supply amount of sludge per fixed time, and the centrifugal force acting on the rotating cylinder. And a control unit to be changed.

If the moisture content of the dehydrated cake is higher than the target predetermined allowable value, to lower it, conversely to increase it if it is significantly lower than the target predetermined value It is desirable to change the operating conditions of the device. In this case, the operator may manually change the operating condition by operating the device. However, according to the configuration described above, the operating condition can be automatically changed without human intervention. it can. This eliminates the need for personnel to adjust the moisture content of the sludge, thereby reducing the operating cost of the apparatus. And since each said operating condition is a main item which affects the moisture content of a dehydrated cake, the moisture content of a dehydrated cake can be adjusted efficiently by changing these items. The predetermined target range herein may be a range defined by the upper limit and the lower limit of the moisture content, or may be a range defined by the upper limit such that the moisture content is below an allowable value. .

  The physical quantity may be a sound pressure level, and may further be a sound pressure level in a predetermined frequency band. When the physical quantity to be measured is a sound pressure level, non-contact measurement is possible. In addition, depending on the configuration of the sludge dewatering device, there is a frequency band where the moisture content of the dewatered cake appears significantly in the sound pressure level, so by measuring the sound pressure level in such a frequency band, accuracy can be improved. High information can be obtained. Since the predetermined frequency band may vary depending on individual devices, the predetermined frequency band may be determined by examining the relationship between the moisture content of the dehydrated cake and the measured sound pressure level in advance by a test or the like.

  Further, the physical quantity measuring device according to the present invention acquires physical quantity information related to an impact when sludge collides with a predetermined object, and based on the acquired physical quantity, the moisture content of the sludge has a predetermined allowable value. You may have the determination part which determines whether it exceeds. According to such a physical quantity measuring device, it is possible to obtain the effects of the present invention by performing the necessary adjustment by adding the physical quantity measuring device to the conventional sludge dewatering device.

  Further, the control method of the sludge dewatering apparatus according to the present invention is a method for controlling a control terminal of a centrifugal sludge dewatering apparatus having a housing that prevents the sludge from being dispersed, and the sludge after dewatering. However, based on the acquired information on the physical quantity and the acquired physical quantity information on impact when colliding with the housing, whether or not the moisture content of the sludge after dehydration exceeds a predetermined allowable value. And determining. The physical quantity may be a sound pressure level.

  Further, based on the acquired physical quantity, the time for centrifuging the sludge, the amount of the chemical solution injected into the sludge, and the injection into the sludge so that the moisture content of the sludge after dehydration becomes a value within a predetermined target range. There may be included a step of changing at least one of the operating conditions among the type of chemical liquid to be performed, the amount of sludge supplied per fixed time, and the centrifugal force for centrifuging sludge. The physical quantity may be a sound pressure level, and the determination may be made based on a sound pressure level in a predetermined frequency band.

  A program according to the present invention is a program for causing a sludge dewatering apparatus to execute each step of the control method.

  In addition, this invention can be grasped | ascertained as a sludge dehydration apparatus which has at least one part of the said structure thru | or function. Moreover, this invention recorded the program for making a computer (processor) perform the control method of the sludge dehydration apparatus containing at least one part of the said process, or such a method, or such a program non-temporarily. It can also be understood as a computer-readable recording medium. Each of the above configurations and processes can be combined with each other to constitute the present invention as long as there is no technical contradiction.

  In the centrifugal sludge dewatering device, it is possible to provide a technique capable of acquiring information about the moisture content of the dewatered cake in real time with a simple device configuration.

FIG. 1 is a schematic diagram illustrating a hardware configuration of the sludge dewatering apparatus according to the first embodiment. FIG. 2 is a diagram illustrating a main configuration of the centrifuge of the sludge dewatering apparatus according to the first embodiment. FIG. 3 is a functional block diagram of the sludge dewatering apparatus according to the first embodiment. FIG. 4 is a graph showing the relationship between the collision sound between the dewatered cake and the inner wall of the casing and the moisture content of the dewatered cake in the experiment. FIG. 5 is a flowchart showing a flow of automatic control of the sludge dewatering apparatus according to the first embodiment. FIG. 6 is a flowchart showing a flow of automatic control of the sludge dewatering apparatus according to the second embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified.

<Example 1>
(Device configuration)
FIG. 1 is a diagram showing a schematic structure of a sludge dewatering device 1 according to the present embodiment. The sludge dewatering apparatus according to the present embodiment is a centrifugal apparatus that performs dewatering using centrifugal force. As shown in FIG. 1, the sludge dewatering device 1 includes a centrifugal separator 10, a control terminal 20, a sludge supply device 30, a chemical liquid injection device 40, a dehydrated cake discharge unit 50, and a separation liquid tank 60. have.

  In the above configuration, the sludge is supplied from the sludge supply device 30 and the chemical solution (for example, polymer flocculant, inorganic flocculant, etc.) is supplied from the chemical liquid injector 40 to the centrifuge 10 and dehydrated in the centrifuge 10. Is done. After the dehydration treatment, the dehydrated cake is discharged to the dehydrated cake discharge unit 50, and the liquid from which the sludge solid components are separated (hereinafter referred to as the separated liquid) is discharged to the separation liquid tank 60. As will be described later, the control terminal 20 holds a program, data, and the like for operating the apparatus, receives various inputs, and controls the apparatus.

  Next, details of the centrifuge 10 will be described. As shown in FIG. 2, the centrifuge 10 according to this embodiment includes a casing 130 in which each of the dewatered cake outlet 131 and the separation liquid outlet 132 is formed below, and a rotation disposed in the casing 130. A cylinder (hereinafter referred to as a bowl 110), and a screw conveyor 120, which is a conveying means for the dehydrated cake to which centrifugal force is applied in the bowl 110, are provided. The centrifuge 10 includes a main motor 140 as a driving mechanism and a pulley and a rotating belt for transmitting the power to the bowl 110 and the screw conveyor 120. The centrifuge 10 further includes a differential speed generating mechanism 150, a sensor box 160 in which a microphone 161 is housed, and a supply pipe 170 for supplying sludge and chemicals into the bowl 110.

The bowl 110 and the screw conveyor 120 are independently rotatable around a horizontal axis, and the power of the main motor 140 as a drive mechanism is transmitted to the pulley on the bowl 110 side via the rotating belt. The bowl 110 rotates at a predetermined rotation speed. The power is transmitted to the screw conveyor 120 through the gear box 152 of the differential speed generating mechanism 150, and the bowl 110 and the screw conveyor 120 are configured to rotate with a relative differential speed.

  Specifically, a differential motor 151 is connected to the gear box 152 via a rotating belt and a pulley, and the brake by reverse rotation is applied so that the screw conveyor 120 rotates slower than the bowl 110. ing. For this reason, the apparatus can be operated at an arbitrary differential speed by setting the rotational speeds of the main motor 140 and the differential motor 151.

  The supply pipe 170 has one end extending into the cavity of the shaft 121 of the screw conveyor 120 as will be described later, and the other end connected to piping from the sludge supply device 30 and the chemical solution injection device 40. Here, the supply pipe 170 is configured to include a first flow path capable of mixing the sludge and the chemical liquid before reaching the dehydrator, and a second flow path capable of supplying the chemical liquid independently of the sludge. May be. With such a configuration, depending on the characteristics of the chemical solution to be used, it is possible to mix the sludge and the chemical solution before reaching the dehydrator, or to supply them independently into the apparatus. Furthermore, it is possible to use a plurality of types of chemical solutions having different characteristics in combination. As an example of the configuration as described above, the supply pipe 170 may be a double pipe structure, for example, or may be a structure that is partitioned into two spaces at the center of the pipe.

  One end of the bowl 110 that applies centrifugal force to the sludge is tapered. The tapered portion is a dewatering part 111 in which sludge in the middle of dehydration (hereinafter referred to as concentrated sludge) transferred by the screw conveyor 120 is separated from a liquid pool to be described later. A dewatered cake discharge port 112 is formed. The body portion 114 of the bowl 110 forms a liquid pool of a mixed liquid of sludge and chemical liquid (hereinafter referred to as a liquid to be treated) supplied into the bowl 110. Further, a separation liquid discharge port 113 for discharging the separation liquid is formed on the end surface on the other end side of the bowl 110. The dewatered cake outlet 112 corresponds to the sludge outlet in the claims.

  The shaft 121 of the screw conveyor 120 has a hollow inside, and one end of the supply pipe 170 is disposed in the hollow. Then, the sludge and the chemical solution supplied from the supply pipe 170 are supplied into the bowl 110 through the supply port 122 provided in the shaft portion 121 of the screw conveyor 120. A spiral screw blade 123 is formed on the outer periphery of the shaft 121 of the screw conveyor 120 to transfer the supplied sludge toward the dewatered cake discharge port 112.

  In the above configuration, when sludge and chemical liquid are supplied into the rotating bowl 110, the sludge and chemical liquid are mixed in the bowl 110, and solid components of sludge settle on the inner peripheral surface of the bowl 110 by the action of centrifugal force. To do. Then, the solid component is transferred toward the liquid separating unit 111 by a screw conveyor 120 that rotates at a differential speed relative to the bowl 110. The solid component separated from the liquid reservoir in the liquid separating unit 111 is dehydrated while being transferred to the dewatered cake discharge port 112 as concentrated sludge, and finally becomes a dehydrated cake and is discharged from the dehydrated cake discharge port 112. . On the other hand, the separation liquid is discharged so as to overflow from the separation liquid discharge port 113 when the liquid to be treated is continuously supplied.

Here, the dehydrated cake discharged from the dehydrated cake discharge port 112 of the bowl 110 rotating at a high speed is discharged while being vigorously scattered. However, when the dehydrated cake collides with the inner wall of the housing 130, Scattering out of the centrifuge 10 is prevented. Then, the dehydrated cake passes through the dehydrated cake outlet 131 provided at the lower portion of the housing 130 and is discharged from the dehydrated cake discharge unit 50. On the other hand, the separation liquid discharged from the separation liquid discharge port 113 of the bowl 110 is accommodated in the separation liquid tank 60 through the separation liquid outlet 132 of the housing 130. Note that the dewatered cake discharge unit 50 may be, for example, a belt conveyor or an inclined slider.

  Next, details of the control terminal 20 will be described. FIG. 3 is a functional block diagram of the sludge dewatering device 1 according to the present embodiment. As illustrated in FIG. 3, the control terminal 20 includes an input unit 210, a storage unit 220, an output unit 230, a determination unit 240, and a control unit 250 as main components. The control terminal 20 is, for example, a general electronic computer, an input device such as a keyboard and a mouse is an input unit 210, a storage device such as a RAM and a hard disk is a storage unit 220, an output device such as a liquid crystal display, a printer, and a speaker, Alternatively, a communication device such as a LAN board corresponds to the output unit 230, and a processing device such as a CPU corresponds to the determination unit 240 and the control unit 250, respectively.

  The input unit 210 has a function of accepting various inputs to the control terminal 20 such as processing execution instructions and various data inputs. The storage unit 220 has a function of storing a program for controlling the sludge dewatering device 1 and various data necessary for controlling the sludge dewatering device 1.

  The output unit 230 has a function of outputting various information related to the sludge dewatering device 1. For example, an input acceptance screen for the terminal and various statuses of the processing device are displayed, and the determination result on the moisture content of the dehydrated cake is displayed and / or voiced as described later.

  The determination unit 240 has a function of determining whether or not the moisture content of the dehydrated cake exceeds a predetermined allowable value based on the sound pressure level in a predetermined frequency band measured by the microphone 161 as described later. Details of the determination will be described later.

  The control unit 250 controls each unit of the sludge dewatering device 1 based on the settings held by the storage unit 220. More specifically, for example, a sludge supply amount control unit 251 that controls the supply amount of sludge from the sludge supply device 30, a chemical solution supply amount control unit 252 that controls the supply amount of chemical solution from the chemical solution injection device 40, and the main motor 140. A main motor control unit 253 for controlling the rotation of the motor, a differential motor control unit 254 for controlling the differential motor 151, and the like.

(Acquisition of moisture content information)
Subsequently, acquisition of information on the moisture content of the dehydrated cake in the present embodiment will be described. As described above, after the dehydrated cake is discharged from the bowl 110, it collides with the inner wall of the housing 130. At this time, a collision sound is generated. When the moisture content of the dehydrated cake becomes sufficiently low, when the dehydrated cake collides with the inner wall of the housing 130, a dry sound is heard that can be heard by the human ear as "para-para ...". .

  This is because when the moisture content of the dehydrated cake becomes sufficiently low, the viscosity and hardness of the dehydrated cake will increase, and its properties will tighten when gripped by hand, such as wet soil. Because. On the other hand, when the dehydration is not sufficient, the viscosity and hardness of the dehydrated cake is lower than the above, and its properties are that it will escape from the gap of the fingers when grasped with a hand, such as a strainer. Even if it collides with the body 130, the above sound is not generated. Thus, there is a correlation between the moisture content of the dewatered cake and the collision sound generated when the dewatered cake is discharged.

FIG. 4 is a graph summarizing experimental results obtained by actually measuring the collision sound between the dewatering cake and the inner wall of the casing and investigating the relationship between the collision sound and the moisture content of the dewatering cake. The vertical axis of the graph represents the average value of sound pressure levels of the 11347 Hz, 11595 Hz, and 11907 Hz frequencies of the impact sound measured for 15 seconds, and the horizontal axis represents the moisture content of the dehydrated cake. Further, the difference in the marker is the difference in frequency, and the circle represents 11347 Hz, the square represents 11595 Hz, and the triangle represents 11907 Hz. From the experimental results, when the moisture content of the dehydrated cake decreases, it can be confirmed that the sound pressure level of the impact sound increases at each of the above frequencies, and it is strong against the moisture content of the dehydrated cake and the impact sound when the dehydrated cake is discharged. It can be confirmed that a correlation exists.

  Therefore, the moisture content of the dehydrated cake is detected by detecting the sound of the dehydrated cake colliding with the inner wall of the housing 130 with the microphone 161 housed in the sensor box 160 and measuring the sound pressure level in a predetermined frequency band. Get information about.

  Specifically, based on the above correlation, the sound pressure level value at which the moisture content of the dehydrated cake is considered to be well below a predetermined allowable value (70%), or a value obtained by adding a predetermined margin to the threshold value Set as. When the sound pressure level in the predetermined frequency band detected by the microphone 161 is less than the threshold value, the determination unit 240 determines that the moisture content of the dehydrated cake exceeds the allowable value (is inappropriate). .

  That is, the acquisition of information about the moisture content of the dehydrated cake in this example does not calculate the value of the moisture content in the dehydrated cake, but the determination result of whether the moisture content exceeds a predetermined allowable value. It means getting. The predetermined frequency band is, for example, 11000 Hz to 11900 Hz. Further, the predetermined threshold value of the sound pressure level is, for example, −60 dB.

(Automatic control of equipment operating conditions)
Next, in the sludge dewatering apparatus 1 of the present embodiment, a process in which the control unit 250 changes the operating conditions so that the moisture content of the dewatered cake is equal to or less than an allowable value will be described. FIG. 5 is a flowchart showing the flow of automatic control related to the determination and adjustment of the water content of the dewatered cake in the sludge dewatering apparatus 1 according to this embodiment.

  First, after the sludge dewatering apparatus 1 is activated, the sludge dewatering process is started under preset initial operation conditions (step S101). Subsequently, the microphone 161 continuously measures the collision sound between the dewatered cake and the inner wall of the housing 130 (step S102), and the apparatus is operated under the same conditions for a predetermined time (step S103). Thereafter, in the determination unit 240, whether or not the collision sound measured by the microphone 161 has a sound pressure level in a predetermined frequency band that is less than a threshold value, that is, whether or not the moisture content of the dehydrated cake exceeds an allowable value. A determination is made (step S104).

  If it is determined in step S104 that the sound pressure level is less than the threshold value, the moisture content of the dehydrated cake exceeds the allowable value (that is, is too high), and the controller 250 operates the operating conditions so that the differential speed is reduced. Is changed (step S105), and the process returns to step S103. In step S104, the same processing is repeated until it is determined that the sound pressure level is equal to or higher than the threshold value.

  In addition, since the solid component of sludge is transferred to the dewatering cake discharge port 112 in a short time (that is, the time during which sludge is centrifuged is short) as the differential speed is large, the moisture content of the dewatering cake increases. For this reason, if the differential speed is changed to a small value, the time during which sludge is centrifuged becomes longer, and the moisture content of the dewatered cake can be lowered. Here, the change of the setting of the differential speed may be stepless by designating the number of rotations of the differential motor, or may be selected from candidates classified into several levels. Moreover, you may change the setting of differential speed | velocity | rate by changing the setting of the time which centrifuges sludge.

On the other hand, when it is determined in step S104 that the sound pressure level is equal to or higher than the threshold value, the moisture content of the dewatered cake is assumed to be lower than the allowable value (that is, appropriate), and the operation under the same condition is continued (step S106). ), The process ends.

  As described above, according to the sludge dewatering device 1 of the present embodiment, it is possible to obtain information on the moisture content of the dehydrated cake without adding a complicated mechanism, and the moisture content of the dehydrated cake is an appropriate value. Thus, the operating conditions of the apparatus can be changed by automatic control. Accordingly, it is not necessary to arrange personnel for measuring the moisture content and operating the apparatus, and it is possible to perform dewatering treatment of sludge at a significantly reduced cost.

<Modification 1>
In the above embodiment, the dehydrated cake discharged from the centrifuge 10 is discharged from the dehydrated cake discharge unit 50, and the separated liquid is stored in the separated liquid tank 60. However, the dehydrated cake discharge unit 50 and the separation liquid tank 60 may be omitted.

  Efficient handling of the dewatered cake and the separated liquid varies depending on the use environment of the apparatus, and the configuration suitable for the various use environments can be performed by using the above-described configuration. For example, the dehydrated cake may be deposited on the ground after being discharged from the dehydrated cake outlet 131, or the separation liquid may be accumulated on the ground or from the separation liquid outlet 132 (after performing an appropriate water quality improvement process if necessary). It may be discharged to a sewer.

<Modification 2>
Moreover, in the said Example, although the operating condition which changes a setting by automatic control was a differential speed, it is not necessarily restricted to this, You may make it change the setting of another operating condition. For example, the amount of chemical liquid injected per predetermined time (or the chemical liquid injection rate, ie, the amount of chemical liquid injected relative to the amount of solid matter in the sludge), the type of chemical liquid to be injected, the amount of sludge supplied per predetermined time, or the centrifuge acting on the bowl 110 Operation conditions such as force may be changed. In addition, the change of the operating condition about a chemical | medical solution also includes not making a chemical | medical solution inject | pour.

  With respect to the chemical injection amount, if the other conditions are the same, the moisture content of the dehydrated cake can be lowered as the amount is increased. For this reason, when the sound pressure level is less than the threshold value, the setting may be changed to increase the injection amount. However, if the injection amount is too large, the moisture content will be increased, and therefore it is preferable to set within the range of the appropriate injection amount.

  Regarding the types of chemical solutions, various organic and inorganic flocculants can be used, and a plurality of types of chemical solutions can be used in combination. For this reason, for example, when only the polymer flocculant is injected and the sound pressure level is less than the threshold value, the setting may be changed so that an inorganic flocculant is also injected in addition to the polymer flocculant.

  As for the supply amount of sludge, the water content of the dewatered cake can be lowered as the other conditions are the same. For this reason, when the sound pressure level is less than the threshold value, the setting may be changed to reduce the supply amount. However, since the moisture content becomes high even if the supply amount is too small, it is preferable to set within the range of the appropriate supply amount.

  As for centrifugal force, the water content of the dehydrated cake can be lowered as the other conditions are the same. For this reason, when the sound pressure level is less than the threshold value, the setting may be changed so as to increase the number of rotations of the power source that rotates the bowl 110, that is, the main motor.

  Further, not only one of these operating conditions may be changed, but a plurality of operating conditions including a differential speed may be appropriately combined and changed.

By enabling a plurality of operation conditions to be automatically set in this way, it is possible to select an efficient operation condition changing method according to the operation environment of the apparatus.

<Example 2>
In the sludge dewatering device 1 in the first embodiment, when the sound pressure level is determined to be equal to or higher than the threshold value, the moisture content of the dewatered cake is equal to or lower than the allowable value (that is, appropriate), and the processing is finished. The operation condition setting may be adjusted in more detail than this. Based on FIG. 6, the processing method will be described as a second embodiment of the present invention. FIG. 6 is a flowchart showing a process of automatically controlling the operation of the sludge dewatering device 1 so that the moisture content of the dewatered cake becomes a value within a predetermined target range. In addition, since it is the same as that of Example 1 about the structure of the sludge dehydration apparatus 1 of a present Example, and acquisition of the information about a moisture content, it uses the same code | symbol and abbreviate | omits detailed description.

  In the sludge dewatering apparatus 1 according to the present embodiment, the operation is continued for a certain period of time after the start of the automatic control process (step S111), and then the determination unit 240 determines whether or not the sound pressure level is less than a predetermined lower limit threshold. Is performed (step S112).

  If it is determined in step S112 that the sound pressure level is less than the lower limit threshold, the controller 250 changes the setting of the operating condition so that the differential speed is reduced, assuming that the moisture content of the dehydrated cake exceeds the target value. Then (step S113), the process returns to step S111. In step S112, the same processing is repeated until it is determined that the sound pressure level is equal to or higher than the lower limit threshold.

  On the other hand, if it is determined in step S112 that the sound pressure level is equal to or higher than the lower limit threshold value, it is subsequently determined whether or not the sound pressure level exceeds a predetermined upper limit threshold value (step S114). Here, when it is determined that the sound pressure level exceeds the predetermined upper limit threshold, the moisture content of the dehydrated cake is assumed to be lower than the target range (that is, too low), and the controller 250 has a large differential speed. The setting of the operating condition is changed so as to be (step S115), and the process returns to step S111. In step S114, the processing from step S111 is repeated until it is determined that the sound pressure level is equal to or lower than the upper limit threshold.

  If it is determined in step S114 that the sound pressure level is equal to or lower than the predetermined upper limit threshold, it is assumed that the moisture content of the dehydrated cake is a value within a predetermined target range, and the operation is continued while maintaining the operation condition setting. (S116), and the process ends.

  By performing the treatment as described above, it becomes possible to prevent the moisture content of the dehydrated cake from becoming too low, so that the moisture content value can be automatically adjusted to a more appropriate range.

  In addition, the above processing may be executed not only once after the start of the operation of the sludge dewatering apparatus 1 but also every predetermined time when the apparatus is in an operating state. In this way, the apparatus automatically and periodically checks whether the moisture content of the dehydrated cake is an appropriate value, and if necessary, the operating conditions can be changed. Thereby, for example, even when the operating environment fluctuates, such as the property of the sludge supplied changes during operation of the apparatus, the moisture content of the dewatered cake can be automatically set to an appropriate value.

  In this embodiment, the case where the operating condition to be changed is a differential speed has been described as an example. However, the present invention is not limited thereto, and the moisture content of the dehydrated cake is automatically adjusted by changing the other operating conditions described above. You may make it do.

<Example 3>
The sludge dewatering device 1 in each of the above embodiments is configured to determine whether the sound pressure level measured by the determination unit 240 is less than a predetermined threshold and automatically control the operating conditions of the device based on the determination. This is not always necessary. That is, the determination result of the determination unit 240 may be output to the output unit 230, and the operator may manually change the operation condition of the apparatus based on the output result.

  If the operator can manually change the operating conditions as described above, the moisture content of the dehydrated cake can be easily adjusted without setting parameters related to changing various operating conditions for automatically controlling the device. Can do.

<Example 4>
Further, as in the third embodiment, when the operator manually changes the operating condition of the apparatus, the sludge dewatering apparatus 1 may be configured not to include the determination unit 240. In this case, the sound pressure level measured by the microphone 161 may be output to the output unit 230, and the operator may manually change the operating condition of the apparatus based on the output result.

  That is, the acquisition of the information about the moisture content of the dehydrated cake in this embodiment is to obtain estimation information as to whether or not the moisture content is below the allowable value based on the sound pressure level output to the output unit 230. Say.

  As described above, if the operator can manually change the operating condition based on the sound pressure level, not only the parameters relating to the change of various operating conditions for automatically controlling the apparatus, but also the timing for making the determination, the sound pressure level The moisture content of the dehydrated cake can be easily adjusted without setting various parameters for the determination process such as the threshold value.

<Example 5>
The sensor box 160 in each of the above embodiments is configured separately from the centrifuge 10, and the sludge dewatering apparatus 1 is configured by retrofitting it to an existing sludge dewatering apparatus. Good. In this case, the sensor box 160 corresponds to the physical quantity measuring device in the claims.

  Here, in addition to the microphone, the physical quantity measuring device has a determination function for determining whether or not the moisture content of the dehydrated cake exceeds a predetermined allowable value based on the sound pressure level of the predetermined frequency band measured by the microphone. It is good also as an apparatus provided with the processor which has, and the output part for outputting this determination result.

  Further, the physical quantity measuring device includes a control unit that changes the operating condition of the sludge dewatering device so that the moisture content of the dewatered cake becomes a value within a predetermined target range based on the physical quantity detected by the microphone. It may be.

  By using the physical quantity measuring apparatus as described above, if the physical quantity measuring apparatus is added to the conventional sludge dewatering apparatus and necessary adjustments are made, the effects of the present invention can be obtained.

<Others>
Each of the above-described embodiments is merely illustrative of the present invention, and the present invention is not limited to the specific forms described above. The present invention can be variously modified within the scope of its technical idea. For example, a piezoelectric element, a load cell, or the like may be used as a sensor of the dehydrating device, and a configuration in which vibration of the casing itself or distortion of the casing when the dehydrated cake collides with the casing may be detected. In addition, the control terminal in each of the above embodiments may be configured integrally with the centrifuge, or may be configured to remotely control the apparatus as a separate configuration.

DESCRIPTION OF SYMBOLS 1 ... Sludge dehydration apparatus 10 ... Centrifugal separator 20 ... Control terminal 30 ... Sludge supply apparatus 40 ... Chemical solution injection apparatus 50 ... Dehydrated cake discharge part 60 ... Separation liquid tank 110 ... Bowl 112 ... Dehydrated cake outlet 120 ... Screw conveyor 130 ... Case 140 ... Main motor 150 ... Differential speed generation mechanism 151 ... Differential motor 152 ... Gear Box 160 ... Sensor box 161 ... Microphone 170 ... Supply pipe

Claims (10)

A centrifugal sludge dewatering device,
A rotating cylinder that has a sludge discharge port for discharging sludge after dehydration, and that rotates around the shaft to centrifuge and dewater sludge inside;
A housing for preventing the sludge after dewatering discharged from the sludge outlet from splashing;
A sensor for detecting a physical quantity related to an impact when the sludge after dewatering discharged from the sludge discharge port collides with the housing;
A sludge dewatering device, comprising: The sludge dewatering according to claim 1, further comprising a determination unit that determines whether or not a moisture content of the sludge after dehydration exceeds a predetermined allowable value based on a physical quantity detected by the sensor. apparatus. A screw conveyor that is disposed inside the rotating cylinder and conveys sludge to the sludge discharge port by rotating in the same direction as the rotating cylinder at a rotation speed different from the rotation speed of the rotating cylinder;
Based on the physical quantity detected by the sensor, the difference in the number of rotations of the rotary cylinder and the screw conveyor is injected into the sludge so that the moisture content of the dewatered sludge is a value within a predetermined target range. A controller that changes at least one of the operating conditions among the amount of the chemical liquid to be applied, the type of the chemical liquid injected into the sludge, the supply amount of sludge per fixed time, and the centrifugal force acting on the rotating cylinder; ,
The sludge dewatering device according to claim 1 or 2, characterized by comprising:   The sludge dewatering device according to any one of claims 1 to 3, wherein the physical quantity is a sound pressure level.   The sludge dewatering device according to claim 4, wherein the physical quantity is a sound pressure level in a predetermined frequency band. Obtain physical quantity information about impact when sludge collides with a given object,
A physical quantity measuring device having a determination unit that determines whether or not the moisture content of the sludge exceeds a predetermined allowable value based on the acquired physical quantity. A method for controlling a centrifugal sludge dewatering device having a casing for preventing sludge scattering after dehydration,
Obtaining physical quantity information relating to impact when dewatered sludge collides with the housing;
Determining whether the moisture content of the sludge after dehydration exceeds a predetermined allowable value based on the acquired physical quantity information;
A control method comprising: Based on the acquired physical quantity, so that the moisture content of the sludge after the dehydration becomes a value within a predetermined target range,
At least one of the time for centrifuging sludge, the amount of chemical liquid injected into the sludge, the type of chemical liquid injected into the sludge, the supply amount of sludge per fixed time, and the centrifugal force for centrifuging sludge The control method according to claim 7, further comprising a step of changing one operating condition.   The control method according to claim 7, wherein the physical quantity is a sound pressure level.   A program for causing a sludge dewatering device to execute each step of the control method according to any one of claims 7 to 9.

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