JP6909143B2 - Operation method of screw press type dehydrator and control device of screw press type dehydrator - Google Patents

Operation method of screw press type dehydrator and control device of screw press type dehydrator Download PDF

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JP6909143B2
JP6909143B2 JP2017238990A JP2017238990A JP6909143B2 JP 6909143 B2 JP6909143 B2 JP 6909143B2 JP 2017238990 A JP2017238990 A JP 2017238990A JP 2017238990 A JP2017238990 A JP 2017238990A JP 6909143 B2 JP6909143 B2 JP 6909143B2
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星野　正明
正明 星野
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本発明は、スラリーを脱水するためのスクリュープレス型脱水機の運転方法及びスクリュープレス型脱水機の制御装置に関する。 The present invention relates to an operation method of a screw press type dehydrator for dehydrating a slurry and a control device of the screw press type dehydrator.

下水処理場や食品工場などで生じる有機性汚泥を固液分離するためにスクリュープレス型脱水機が使用されている。スクリュープレス型脱水機は、円筒状のスクリーンの内部にスクリューが配置され、スクリューとスクリューの先端の脱水ケーキの排出口に設けられた背圧プレッサ（「押圧板」ともいう。）によって、スクリーンの内部に導入された凝集汚泥を加圧しながら脱水する装置である。予め有機性汚泥に凝集剤が添加された凝集汚泥がスクリュープレス型脱水機に導入される被圧搾物となる。 A screw press type dehydrator is used to separate organic sludge generated in sewage treatment plants and food factories into solid and liquid. In a screw press type dehydrator, a screw is placed inside a cylindrical screen, and a back pressure presser (also referred to as a "pressing plate") provided at the screw and the outlet of the dehydrated cake at the tip of the screw is used to display the screen. It is a device that dehydrates the coagulated sludge introduced inside while pressurizing it. The coagulated sludge to which the coagulant is added to the organic sludge in advance becomes the pressed product to be introduced into the screw press type dehydrator.

特許文献１には、スクリュープレスから排出する汚泥の脱水性を安定させるために、排出部の開口率をリアルタイムに計測し、所定の開口率となるよう押圧板の位置を調整するスクリュープレスの排出部開口率一定制御方法が提案されている。 In Patent Document 1, in order to stabilize the dehydration of sludge discharged from the screw press, the opening ratio of the discharge portion is measured in real time, and the position of the pressing plate is adjusted so as to have a predetermined opening ratio. A method for controlling a constant aperture ratio has been proposed.

当該排出部開口率一定制御方法は、予め基準開口率と、押圧板の押圧力を段階的に増減させる値を設定し、スクリュープレス運転中に算出した開口率と基準開口率とを比較し、開口率が基準開口率より大きい場合、押圧板の押圧力を段階的に増加させ、開口率が基準開口率より小さい場合、押圧板の押圧力を段階的に減少させて開口率を基準開口率に制御するように構成されている。 In the discharge part opening ratio constant control method, a reference opening ratio and a value for gradually increasing or decreasing the pressing force of the pressing plate are set in advance, and the opening ratio calculated during the screw press operation is compared with the reference opening ratio. When the aperture ratio is larger than the reference aperture ratio, the pressing force of the pressing plate is gradually increased, and when the opening ratio is smaller than the reference opening ratio, the pressing force of the pressing plate is gradually decreased to set the opening ratio as the reference aperture ratio. It is configured to control.

特許文献２には、運転開始時又は高負荷時に、濾過水に固形物が混入したり、スクリュー駆動装置や汚泥ポンプの異常停止が生じることなく、脱水を安定して行うことができるスクリュープレス脱水機の運転方法が開示されている、 Patent Document 2 states that screw press dehydration can be performed stably without solid matter being mixed in the filtered water or abnormal stoppage of the screw drive device or sludge pump at the start of operation or at a high load. The operation method of the aircraft is disclosed,

当該スクリュープレス脱水機の運転方法は、スクリュープレス脱水機の運転開始時又は高負荷時に、押圧板自動開閉機構により押圧板を開位置まで移動させて汚泥ケーキの排出を促進させるように構成されている。スクリュープレス脱水機前段の水位またはスクリュープレス脱水機への流入圧力によりスクリュープレス脱水機の負荷が判断される。 The operating method of the screw press dehydrator is configured to move the pressing plate to the open position by the pressing plate automatic opening / closing mechanism at the start of operation of the screw press dehydrating machine or at a high load to promote the discharge of sludge cake. There is. The load on the screw press dehydrator is determined by the water level in the previous stage of the screw press dehydrator or the inflow pressure into the screw press dehydrator.

特開２０１７−８７２３８号公報JP-A-2017-87238 特開２００１−３８４９０号公報Japanese Unexamined Patent Publication No. 2001-388490

スクリュープレス脱水機は、起動時に含水率の悪いケーキが排出されやすく、適正な脱水圧になるまでに時間がかかるという特性があり、上述した特許文献１に開示された制御方法のように背圧プレッサの開度（開口率）を一定に維持する制御や圧力を一定に維持する制御では、適正な脱水圧に上がるまでに時間がかかり、含水率の悪いケーキが起動時に多量に排出されるという問題があった。 The screw press dehydrator has a characteristic that a cake having a poor water content is easily discharged at the time of starting and it takes time to reach an appropriate dehydration pressure, and the back pressure is similar to the control method disclosed in Patent Document 1 described above. In the control that keeps the opening (opening ratio) of the presser constant and the control that keeps the pressure constant, it takes time to reach the proper dehydration pressure, and a large amount of cake with poor water content is discharged at startup. There was a problem.

また、スクリュープレス脱水機は、繊維状物量が少なく強熱減量物ＶＴＳ（Volatile Total Solids）の高い絞り難い汚泥などを圧搾しているときに押圧板に必要以上の圧力をかけると、搬送不良を起こして脱水ケーキの含水率がさらに悪化する場合がある。そのため背圧プレッサに付与する圧力を一定に維持する制御を採用すると、結果的に被圧搾物に必要以上の圧力が付与されて搬送不良が発生しやすくなるという問題があった。 In addition, the screw press dewatering machine causes poor transportation if pressure is applied to the pressing plate more than necessary when squeezing sludge that is difficult to squeeze and has a small amount of fibrous material and high ignition loss VTS (Volatile Total Solids). The moisture content of the dehydrated cake may be further deteriorated by raising it. Therefore, if a control for maintaining a constant pressure applied to the back pressure presser is adopted, as a result, an excessive pressure is applied to the pressed object, and there is a problem that transport failure is likely to occur.

さらに、スクリュープレス脱水機は、繊維状物量が多く蒸発残留物ＴＳ（Total Solids）の高い絞りやすい汚泥などを圧搾しているときに背圧プレッサに高い圧力をかけると、含水率がより低下しやすく、さらに含水率が低下し過ぎても供回りが発生し、脱水不能になる場合がある。そのため開度一定制御や圧力一定制御を採用すると、脱水ケーキの含水率を下げたくない場合でも含水率が必要以上に低下し、場合によっては供回りが発生して脱水不能になるという問題もあった。 Furthermore, when the screw press dehydrator is squeezing sludge that has a large amount of fibrous material and high evaporation residue TS (Total Solids) and is easy to squeeze, if a high pressure is applied to the back pressure presser, the water content will be further reduced. It is easy, and even if the water content is too low, it may become impossible to dehydrate due to the occurrence of back pressure. Therefore, if constant opening control or constant pressure control is adopted, even if you do not want to reduce the moisture content of the dehydrated cake, the moisture content will drop more than necessary, and in some cases, there will be a problem that dehydration will not be possible due to the occurrence of rotation. rice field.

本発明の目的は、上述した問題点に鑑み、起動後に速やかに適正な脱水圧に到達し、含水率が安定した脱水ケーキが得られるスクリュープレス型脱水機の運転方法及びスクリュープレス型脱水機の制御装置を提供する点にある。 In view of the above-mentioned problems, an object of the present invention is an operation method of a screw press type dehydrator and a screw press type dehydrator capable of quickly reaching an appropriate dehydration pressure after starting and obtaining a dehydrated cake having a stable water content. The point is to provide a control device.

上述の目的を達成するため、本発明によるスクリュープレス型脱水機の運転方法の第一の特徴構成は、スラリーを脱水するためのスクリュープレス型脱水機の運転方法であって、汚泥性状に基づいて予め設定されたプレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯに対して、標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧で運転を開始する始動ステップと、前記始動ステップから前記初期プレッサ圧を保持して所定時間経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐを調整する初期プレッサ圧調整ステップと、
を備えている点にある。 To achieve the above object, a first characteristic feature of the method of operating a screw press type dehydrator according to the present invention is a method of operating a screw press type dehydrator for dehydrating slurries, based on the sludge characteristics The initial presser set above the standard value PO and below the upper limit value PH with respect to the preset upper limit value PH, lower limit value PL, and standard value PO between the upper limit value PH and the lower limit value PL of the presser pressure P. The presser pressure P is between the upper limit value PH and the lower limit value PL based on the starting step of starting the operation with pressure and the opening degree of the back pressure presser after the initial presser pressure is held from the starting step and a predetermined time elapses. With the initial presser pressure adjustment step to adjust
It is in the point that it has.

汚泥性状に基づいて予め設定された標準値ＰＯより高く上限値ＰＨ以下のある程度の高い初期プレッサ圧が付与された状態で起動される始動ステップが実行されて、その状態が所定時間継続されることにより機内圧力が上昇して早期に適切な脱水圧になるので、起動時に含水率の高いケーキの排出量が効果的に抑制される。そして所定時間後に初期プレッサ圧調整ステップが実行され、その時の背圧プレッサの開度に基づいて上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐが適切な値に調整されるので、脱水ケーキの排出不良が生じることなく含水率が適切に調整される。 The start step is executed with a certain high initial presser pressure higher than the preset standard value PO based on the sludge properties and lower than the upper limit PH, and the state is continued for a predetermined time. As a result, the pressure inside the machine rises and the dehydration pressure becomes appropriate at an early stage, so that the amount of cake with a high water content is effectively suppressed at the time of start-up. Then, after a predetermined time, the initial presser pressure adjusting step is executed, and the presser pressure P is adjusted to an appropriate value between the upper limit value PH and the lower limit value PL based on the opening degree of the back pressure presser at that time. The moisture content is adjusted appropriately without causing poor discharge.

同第二の特徴構成は、上述の第一の特徴構成に加えて、前記初期プレッサ圧調整ステップにおいて、前記所定時間経過後の背圧プレッサの開度Ｌが、予め設定された第１閾値Ｌ１未満であればプレッサ圧Ｐを下限値ＰＬに調整し、第１閾値Ｌ１を超えればプレッサ圧Ｐを標準値ＰＯに調整する点にある。 The second feature structure, in addition to the first characteristic feature of the above mentioned, in the initial presser pressure adjusting step, the opening L of the back pressure presser after said predetermined time, the first threshold value set in advance If it is less than L1, the presser pressure P is adjusted to the lower limit value PL, and if it exceeds the first threshold value L1, the presser pressure P is adjusted to the standard value PO.

第１閾値Ｌ１を指標に脱水ケーキの脱水性が評価される。背圧プレッサの開度Ｌが第１閾値Ｌ１未満であれば脱水性が悪いと判断されて、プレッサ圧Ｐが下限値ＰＬに調整されることで排出不良の発生を未然に防ぐことができる。背圧プレッサの開度Ｌが第１閾値Ｌ１を超えていれば脱水性が悪くないと判断されて、必要以上に含水率が低下しないようにプレッサ圧Ｐが標準値ＰＯに調整される。 The dehydration property of the dehydrated cake is evaluated using the first threshold value L1 as an index. If the opening degree L of the back pressure presser is less than the first threshold value L1, it is determined that the dehydration property is poor, and the presser pressure P is adjusted to the lower limit value PL, so that the occurrence of discharge failure can be prevented. If the opening degree L of the back pressure presser exceeds the first threshold value L1, it is determined that the dehydration property is not bad, and the presser pressure P is adjusted to the standard value PO so that the water content does not decrease more than necessary.

同第三の特徴構成は、上述の第一または第二の特徴構成に加えて、前記初期プレッサ圧調整ステップの後に、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを所定値または所定範囲に維持するプレッサ開度維持ステップを備えている点にある。 The third feature structure, in addition to the first or second characteristic feature of the above mentioned, after the initial presser pressure adjusting step, by adjusting the presser pressure P between the upper limit PH and the lower limit PL The point is that the presser opening degree maintaining step for maintaining the opening degree L of the back pressure presser within a predetermined value or a predetermined range is provided.

初期プレッサ圧調整ステップの後にプレッサ開度維持ステップが実行されて、背圧プレッサの開度Ｌが所定値または所定範囲に維持されるように、背圧プレッサの開度Ｌに基づいてプレッサ圧Ｐが上限値ＰＨと下限値ＰＬの間で調整される。例えば、背圧プレッサの開度Ｌが所定値より大きければプレッサ圧Ｐが上昇され、背圧プレッサの開度Ｌが所定値より小さければプレッサ圧Ｐが低下される。 The presser opening degree maintaining step is executed after the initial presser pressure adjusting step, and the presser pressure P is based on the back pressure presser opening degree L so that the back pressure presser opening degree L is maintained at a predetermined value or a predetermined range. Is adjusted between the upper limit PH and the lower limit PL. For example, if the opening degree L of the back pressure presser is larger than a predetermined value, the presser pressure P is increased, and if the opening degree L of the back pressure presser is smaller than the predetermined value, the presser pressure P is decreased.

同第四の特徴構成は、上述の第三の特徴構成に加えて、前記プレッサ開度維持ステップは、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを第１閾値Ｌ１と第１の閾値Ｌ１より大きな値に設定された第２閾値Ｌ２との間に維持する点にある。 The fourth characterizing feature of, in addition to the third characteristic feature of the above mentioned, the presser opening sustain step, by adjusting the presser pressure P between the upper limit PH and the lower limit value PL, the back pressure presser The opening point L is maintained between the first threshold value L1 and the second threshold value L2 set to a value larger than the first threshold value L1.

背圧プレッサの開度Ｌが第１閾値Ｌ１とそれより大きな値の第２閾値Ｌ２との間に維持されるように、背圧プレッサの開度Ｌに基づいてプレッサ圧Ｐが上限値ＰＨと下限値ＰＬの間で調整される結果、脱水ケーキの含水率が適切な値で脱水できるようになる。 The presser pressure P is set to the upper limit PH based on the back pressure presser opening L so that the back pressure presser opening L is maintained between the first threshold L1 and the second threshold L2 having a larger value. As a result of adjusting between the lower limit values PL, the water content of the dehydrated cake can be dehydrated at an appropriate value.

同第五の特徴構成は、上述の第四の特徴構成に加えて、前記プレッサ開度維持ステップにおいて、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えるとプレッサ圧Ｐを標準値ＰＯに向けて調整する点にある。 The fifth characterizing feature of, in addition to the fourth characterizing feature of the above mentioned, the in presser opening sustain step, a standard value opening L is a presser pressure P exceeds the second threshold value L2 of the back pressure presser PO There is a point to adjust toward.

汚泥の脱水性がよいことに起因して、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えた場合に、脱水ケーキの含水率が必要以上に低下しないように、プレッサ圧Ｐが低下するように標準値ＰＯに向けて調整される。 Due to the good dehydration of sludge, when the opening L of the back pressure presser exceeds the second threshold value L2, the presser pressure P decreases so that the water content of the dehydrated cake does not decrease more than necessary. Is adjusted toward the standard value PO.

同第六の特徴構成は、上述の第四の特徴構成に加えて、前記プレッサ開度維持ステップにおいて、背圧プレッサの開度Ｌが第２閾値Ｌ２を超え、且つ、スクリュー回転トルクＳが予め設定された閾値ＳＨを超えるとプレッサ圧Ｐを下限値ＰＬに向けて調整する点にある。 The sixth characterizing feature of, in addition to the fourth characterizing feature of the above mentioned, in the presser opening sustain step, beyond the opening L of the back pressure presser is a second threshold value L2, and the screw rotating torque S is When the preset threshold value SH is exceeded, the presser pressure P is adjusted toward the lower limit value PL.

汚泥の脱水性がよいことに起因して、背圧プレッサの開度Ｌが第２閾値Ｌ２を超え、スクリュー回転トルクＳが閾値ＳＨを超えると、脱水ケーキの含水率が必要以上に低下し、さらには被圧搾物とスクリューとの供回りが発生する虞がある。そのような場合に、プレッサ圧Ｐが下限値ＰＬに向けて調整されることにより、必要以上の含水率の低下や供回りの発生といった不都合な事態の発生が未然に回避される。 When the opening degree L of the back pressure presser exceeds the second threshold value L2 and the screw rotation torque S exceeds the threshold value SH due to the good dehydration of sludge, the water content of the dehydrated cake drops more than necessary. Furthermore, there is a risk that the squeezed material and the screw will rotate together. In such a case, by adjusting the presser pressure P toward the lower limit value PL, the occurrence of inconvenient situations such as an unnecessarily low water content and the occurrence of rotation can be avoided.

本発明によるスクリュープレス型脱水機の制御装置の第一の特徴構成は、スラリーを脱水するためのスクリュープレス型脱水機の制御装置であって、 汚泥性状に基づいて予め設定されたプレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯに対して、標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧で運転を開始する始動制御部と、運転開始から前記初期プレッサ圧を保持して所定時間経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐを調整する初期プレッサ圧調整制御部と、を備えている点にある。 The first characteristic feature of the control device, for a screw press type dewatering machine according to the present invention is a control device, for a screw press type dehydrator for dehydrating slurries, presser pressure P set in advance based on the sludge characteristics Start control to start operation with the initial presser pressure set higher than the standard value PO and below the upper limit value PH with respect to the upper limit value PH, the lower limit value PL, and the standard value PO between the upper limit value PH and the lower limit value PL. Initial presser pressure adjustment control that holds the initial presser pressure from the start of operation and adjusts the presser pressure P between the upper limit PH and the lower limit PL based on the opening degree of the back pressure press after a predetermined time has elapsed. The point is that it has a part.

同第二の特徴構成は、上述の第一の特徴構成に加えて、前記初期プレッサ圧調整制御部は、前記所定時間経過後の背圧プレッサの開度Ｌが、予め設定された第１閾値Ｌ１未満であればプレッサ圧Ｐを下限値ＰＬに調整し、第１閾値Ｌ１を超えればプレッサ圧Ｐを標準値ＰＯに調整する点にある。 The second feature structure, in addition to the first characteristic feature of the above mentioned, the initial presser pressure adjustment control unit, the opening degree L of the back pressure presser after said predetermined time, first a preset If it is less than the threshold value L1, the presser pressure P is adjusted to the lower limit value PL, and if it exceeds the first threshold value L1, the presser pressure P is adjusted to the standard value PO.

同第三の特徴構成は、上述の第一または第二の特徴構成に加えて、前記初期プレッサ圧調整制御部による初期プレッサ圧調整制御の後に、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを所定値または所定範囲に維持するプレッサ開度維持制御部を備えている点にある。 The third feature structure, in addition to the first or second characteristic feature of the above mentioned, the initial presser after initial presser pressure adjustment control by the pressure adjustment control unit, up to presser pressure P value PH and the lower limit PL The point is that the presser opening degree maintaining control unit for maintaining the opening degree L of the back pressure presser within a predetermined value or a predetermined range is provided by adjusting between the two.

同第四の特徴構成は、上述の第三の特徴構成に加えて、前記プレッサ開度維持制御部は、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを第１閾値と第１の閾値Ｌ１より大きな値に設定された第２閾値Ｌ２との間に維持する点にある。 The fourth characterizing feature of, in addition to the third characteristic feature of the above mentioned, the presser opening maintenance control unit, by adjusting the presser pressure P between the upper limit PH and the lower limit value PL, the back pressure The point is that the opening degree L of the presser is maintained between the first threshold value and the second threshold value L2 set to a value larger than the first threshold value L1.

同第五の特徴構成は、上述の第四の特徴構成に加えて、前記プレッサ開度維持制御部は、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えるとプレッサ圧Ｐを標準値ＰＯに向けて調整する点にある。 The fifth characterizing feature of, in addition to the fourth characterizing feature of the above mentioned, the presser opening maintenance control unit, when the opening degree L of the back pressure presser exceeds the second threshold value L2 presser pressure P standard value The point is to adjust for PO.

同第六の特徴構成は、上述の第四の特徴構成に加えて、前記プレッサ開度維持制御部は、背圧プレッサの開度Ｌが第２閾値Ｌ２を超え、且つ、スクリュー回転トルクＳが予め設定された閾値ＳＨを超えるとプレッサ圧Ｐを下限値ＰＬに向けて調整する点にある。 The sixth characterizing feature of, in addition to the fourth characterizing feature of the above mentioned, the presser opening maintenance control unit, the opening degree L of the back pressure presser exceeds the second threshold value L2, and the screw rotating torque S Is a point where the presser pressure P is adjusted toward the lower limit value PL when the value exceeds the preset threshold value SH.

以上説明した通り、本発明によれば、起動後に速やかに適正な脱水圧に到達し、含水率が安定した脱水ケーキが得られるスクリュープレス型脱水機の運転方法及びスクリュープレス型脱水機の制御装置を提供することができるようになった。 As described above, according to the present invention, the operation method of the screw press type dehydrator and the control device of the screw press type dehydrator can quickly reach an appropriate dehydration pressure after starting and obtain a dehydrated cake having a stable water content. Can now be provided.

本発明によるスクリュープレス型脱水機の構造の説明図Explanatory drawing of structure of screw press type dehydrator by this invention 本発明によるスクリュープレス型脱水機の要部の機能説明図Functional explanatory view of the main part of the screw press type dehydrator according to the present invention 制御装置により実行される制御手順を示すフローチャートFlow chart showing the control procedure executed by the control device

以下に、本発明によるスクリュープレス型脱水機の運転方法及びスクリュープレス型脱水機の制御装置の実施形態を説明する。
図１には、外胴スクリーン２の一部が除去されたスクリュープレス型脱水機１０の構造が示されている。スクリュープレス型脱水機１０は、基台１に設けられた外胴スクリーン２、上下二本のスクリュー軸３，４、背圧プレッサ５、エアシリンダー６、駆動装置７、洗浄装置８（図２参照）、凝集混和装置１１などを備えて構成されている。 Hereinafter, an operation method of the screw press type dehydrator and an embodiment of a control device of the screw press type dehydrator according to the present invention will be described.
FIG. 1 shows the structure of the screw press type dehydrator 10 from which a part of the outer body screen 2 is removed. The screw press type dehydrator 10 includes an outer body screen 2 provided on the base 1, two upper and lower screw shafts 3 and 4, a back pressure presser 5, an air cylinder 6, a drive device 7, and a cleaning device 8 (see FIG. 2). ), The coagulation / mixing device 11 and the like are provided.

外胴スクリーン２は、汚泥投入側端部１ａから汚泥排出側端部１ｂの間で軸心が水平姿勢となるように配された円筒状の金属ろ材で構成され、軸心方向に複数のセグメントに区分されている。汚泥投入側端部１ａに近接したセグメントには高圧ろ過による目詰まりに対応すべく間隔０．２〜０．５ｍｍ程度のウェッジワイヤで構成された金属ろ材２ａが配され、それより下流側のセグメントには開口径が０．５〜１．５ｍｍ程度のパンチングメタルで構成された金属ろ材２ｂが配されている。 The outer body screen 2 is composed of a cylindrical metal filter medium arranged so that the axis is in a horizontal posture between the sludge input side end 1a and the sludge discharge side end 1b, and has a plurality of segments in the axis direction. It is divided into. A metal filter medium 2a composed of wedge wires with an interval of about 0.2 to 0.5 mm is arranged in a segment close to the sludge injection side end 1a in order to cope with clogging due to high-pressure filtration, and a segment on the downstream side thereof. A metal filter medium 2b made of punching metal having an opening diameter of about 0.5 to 1.5 mm is arranged in the filter medium.

スクリュー軸３，４には、汚泥投入側端部１ａから汚泥排出側端部１ｂに向けてピッチが次第に短く、つまり羽根の１ピッチ当たりのろ室容積が減少するように設定されたスクリュー羽根３ａ，４ａが設けられている。なお、スクリュー軸３，４の軸径を汚泥排出側ほど太くすることでスクリュー羽根の１ピッチ当たりのろ室容積が減少するように構成してもよい。基台１に設けられた電動モータなどで構成される駆動装置７により駆動連結機構であるギヤ７ａ，７ｂを介して当該スクリュー軸３，４は互いに反対方向に回転駆動される。 The screw blades 3a are set so that the pitch of the screw shafts 3 and 4 is gradually shortened from the sludge input side end 1a to the sludge discharge side end 1b, that is, the filter chamber volume per blade pitch is reduced. , 4a are provided. The diameter of the screw shafts 3 and 4 may be increased toward the sludge discharge side so that the volume of the filter chamber per pitch of the screw blades is reduced. The screw shafts 3 and 4 are rotationally driven in opposite directions by a drive device 7 composed of an electric motor or the like provided on the base 1 via gears 7a and 7b which are drive connection mechanisms.

スラリー即ち被圧搾物となる有機性汚泥は、ポンプＰによって凝集混和装置１１に圧送され、凝集混和装置１１に投入された凝集剤とともに撹拌羽根で撹拌混合されてフロックを形成した後に、汚泥投入側端部１ａから外胴スクリーン２で仕切られるろ室に圧入される。 The slurry, that is, the organic sludge to be pressed, is pumped to the coagulation / mixing device 11 by the pump P, and is stirred and mixed with the coagulant charged into the coagulation / mixing device 11 with a stirring blade to form flocs, and then the sludge input side. It is press-fitted from the end portion 1a into the filter chamber partitioned by the outer body screen 2.

ろ室に圧入された被圧搾物は、スクリュー軸３，４の回転に伴ってスクリュー羽根３ａ，４ａにより汚泥排出側端部１ｂに向けて搬送される過程で、外胴スクリーン２でろ過され、２本のスクリュー軸３，４の回転によって中央部に巻き込まれて強い圧密・剪断脱水効果を受けつつ、ピッチが次第に短く設定されたスクリュー羽根３ａ，４ａにより下流側への搬送に伴って次第に圧密化される。 The consolidated material pressed into the filter chamber is filtered by the outer cylinder screen 2 in the process of being conveyed by the screw blades 3a and 4a toward the sludge discharge side end 1b as the screw shafts 3 and 4 rotate. The rotation of the two screw shafts 3 and 4 causes them to be caught in the central part and receive a strong consolidation / shear dehydration effect, while the screw blades 3a and 4a whose pitch is set to be gradually shortened to gradually compact the screw blades 3a and 4a as they are conveyed to the downstream side. Be transformed.

汚泥排出側端部１ｂにはスクリーン２の開口に対向するように背圧プレッサ５が配されている。背圧プレッサ５はスクリュー軸３，４の先端側がブッシュタイプのすべり軸受を介して貫通するように配置され、エアシリンダー６及び押圧シャフト６ａにより所定圧で汚泥投入側端部１ａに向けて押圧駆動される。 A back pressure presser 5 is arranged at the sludge discharge side end 1b so as to face the opening of the screen 2. The back pressure presser 5 is arranged so that the tip side of the screw shafts 3 and 4 penetrates through the bush type slide bearing, and is pressed by the air cylinder 6 and the pressing shaft 6a toward the sludge charging side end portion 1a at a predetermined pressure. Will be done.

圧搾汚泥から受ける反力とプレッサ圧とのバランスにより形成されるスクリーン２の端部と背圧プレッサ５の外周部に形成される間隙から脱水ケーキが排出される。 The dehydrated cake is discharged from the gap formed between the end portion of the screen 2 and the outer peripheral portion of the back pressure presser 5 formed by the balance between the reaction force received from the pressed sludge and the presser pressure.

背圧プレッサ５を加圧するアクチュエータとしてエアシリンダー７以外に油圧シリンダー、電動シリンダーなどを用いることも可能である。 In addition to the air cylinder 7, a hydraulic cylinder, an electric cylinder, or the like can be used as an actuator for pressurizing the back pressure presser 5.

上述したスクリュープレス型脱水機には制御装置２０が設けられ、当該制御装置２０によって運転制御される。制御装置２０はＣＰＵ、メモリ、入出力回路などを備えたコンピュータで構成され、メモリに格納された制御プログラムがＣＰＵで実行されることにより所期の運転制御が具現化される。 The screw press type dehydrator described above is provided with a control device 20, and the operation is controlled by the control device 20. The control device 20 is composed of a computer including a CPU, a memory, an input / output circuit, and the like, and the desired operation control is realized by executing the control program stored in the memory by the CPU.

駆動装置７に組み込まれた電動モータのトルクを検出するトルクセンサ１３、スクリーン２の端部と背圧プレッサ５の外周部に形成される間隙を計測する超音波センサ１２の各検出値が制御装置２０に入力される。なお、超音波センサ１２は基台１に立設された後フレームに取付けられ、後フレームと背圧プレッサ５の背面との間の距離が求められ、当該距離を基準に制御装置２０によってスクリーン２の端部と背圧プレッサ５の外周部に形成される間隙が算出されるように構成されている。 Each detection value of the torque sensor 13 that detects the torque of the electric motor incorporated in the drive device 7 and the ultrasonic sensor 12 that measures the gap formed between the end portion of the screen 2 and the outer peripheral portion of the back pressure presser 5 is the control device. It is input to 20. The ultrasonic sensor 12 is attached to a rear frame erected on the base 1, and a distance between the rear frame and the back surface of the back pressure presser 5 is obtained. Based on the distance, the screen 2 is operated by the control device 20. The gap formed between the end portion of the back pressure presser 5 and the outer peripheral portion of the back pressure presser 5 is calculated.

一般的に、被圧搾物である汚泥の性状は、蒸発残留物ＴＳ（Total Solids）、蒸発減量物ＶＴＳ（Volatile Total Solids）、繊維状物量により把握することができる。 Generally, the properties of sludge, which is a pressed product, can be grasped from the evaporation residue TS (Total Solids), the evaporation weight loss product VTS (Volatile Total Solids), and the amount of fibrous material.

蒸発残留物ＴＳ（Total Solids）とは、汚泥中の固形物量を示す指標で、試料を１０５〜１１０℃で乾燥した後に残留する物質量（ｍｇ／Ｌまたはｍｇ／ｋｇ）で表される。蒸発残留物ＴＳは強熱減量と強熱残留物の和、或いは、ＳＳと溶解性物質の和となる。 Evaporation residue TS (Total Solids) is an index showing the amount of solid matter in sludge, and is represented by the amount of substance (mg / L or mg / kg) remaining after the sample is dried at 105 to 110 ° C. The evaporation residue TS is the sum of ignition loss and ignition residue, or the sum of SS and a soluble substance.

強熱減量物ＶＴＳ（Volatile Total Solids）とは、汚水や汚泥中の有機物量を示す指標。蒸発残留物ＴＳを６００℃で１時間強熱灰化して揮発する物質量をｍｇ／Ｌまたはｍｇ／ｋｇで表される。ＶＴＳの値が小さいほど脱水性は良くなる。 Ignition weight loss VTS (Volatile Total Solids) is an index showing the amount of organic matter in sewage and sludge. The amount of substance volatilized by igniting the evaporation residue TS at 600 ° C. for 1 hour is expressed in mg / L or mg / kg. The smaller the VTS value, the better the dehydration.

また、汚泥に含まれる繊維状物量が多ければフロックの核となりやすく、凝集剤を添加したときの凝集性が上昇する。 In addition, if the amount of fibrous material contained in the sludge is large, it tends to become a core of flocs, and the cohesiveness when a flocculant is added increases.

蒸発残留物ＴＳが高く、強熱減量物ＶＴＳが低く、繊維状物量が多い汚泥は脱水しやすく、脱水ケーキの含水率が低くなるため、絞り過ぎないようにスクリュー軸３，４の回転数及び背圧プレッサ５に付与されるプレッサ圧を調整する必要がある。また、蒸発残留物ＴＳが低く、強熱減量物ＶＴＳが高く、繊維状物量が少ない汚泥は脱水が容易でなく、脱水ケーキの含水率が高くなるため、脱水ケーキの練り込み、排出不良を回避すべくスクリュー軸３，４の回転数及び背圧プレッサ５に付与されるプレッサ圧を調整する必要がある。 Sludge with a high evaporation residue TS, a low ignition loss VTS, and a large amount of fibrous material is easily dehydrated, and the water content of the dehydrated cake is low. It is necessary to adjust the presser pressure applied to the back pressure presser 5. In addition, sludge with a low evaporation residue TS, a high ignition loss VTS, and a small amount of fibrous material is not easy to dehydrate, and the water content of the dehydrated cake is high, so that the dehydrated cake is kneaded and poor discharge is avoided. Therefore, it is necessary to adjust the rotation speeds of the screw shafts 3 and 4 and the presser pressure applied to the back pressure presser 5.

制御装置２０はトルクセンサ１３及び超音波センサ１２の各検出値に基づいて上述したような汚泥の性状を推定し、目標とする含水率で目標とする処理量の脱水ケーキが得られるようにスクリュー軸３，４の回転数及び背圧プレッサ５に付与されるプレッサ圧を演算導出し、導出されたスクリュー軸３，４の回転数となるように電動モータに制御信号を出力し、導出されたプレッサ圧となるようにエアシリンダー６に制御信号を出力する。 The control device 20 estimates the properties of sludge as described above based on the detected values of the torque sensor 13 and the ultrasonic sensor 12, and screwes the sludge so that a dehydrated cake having a target processing amount can be obtained at a target water content. The rotation speeds of the shafts 3 and 4 and the presser pressure applied to the back pressure presser 5 are calculated and derived, and a control signal is output to the electric motor so as to be the derived rotation speeds of the screw shafts 3 and 4, and the derivation is performed. A control signal is output to the air cylinder 6 so as to be a presser pressure.

図３には、制御装置２０により実行される制御手順、つまり運転方法が示されている。
制御装置２０は、電源が投入されると、先ず始動ステップ（Ｓ０，Ｓ１）と、初期プレッサ圧調整ステップ（Ｓ２〜Ｓ４）とを実行し、その後、プレッサ開度維持ステップ（Ｓ５〜Ｓ１７）を繰返し実行する。 FIG. 3 shows a control procedure executed by the control device 20, that is, an operation method.
When the power is turned on, the control device 20 first executes a starting step (S0, S1) and an initial presser pressure adjusting step (S2 to S4), and then performs a presser opening degree maintaining step (S5 to S17). Execute repeatedly.

ろ室に圧入される汚泥の大まかな性状に基づいて、脱水ケーキの含水率が目標値になるように、そして脱水処理量（ｋｇ−ＤＳ／ｈ）が目標処理量となるように、スクリュー軸３，４の回転数（ｒｐｍ）が事前に設定され、プレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯが事前に設定される。 Based on the rough properties of the sludge that is press-fitted into the filter chamber, the screw shaft so that the moisture content of the dewatered cake becomes the target value and the dehydration treatment amount (kg-DS / h) becomes the target treatment amount. The rotation speeds (rpm) of 3 and 4 are preset, and the upper limit PH, the lower limit PL, and the standard value PO between the upper limit PH and the lower limit PL of the presser pressure P are preset.

また、背圧プレッサの開度Ｌについても、第１閾値Ｌ１、第２閾値Ｌ２、第３閾値Ｌ３（Ｌ１＜Ｌ２＜Ｌ３）が設定されている。第１閾値Ｌ１は脱水性の悪い汚泥に練り込みが発生しないように定められた値であり、第３閾値は脱水性の良い汚泥が過剰に脱水されないように定められた値である。さらに、電動モータ（スクリュー軸）に許容される最大トルクＳＨが設定されている。 Further, with respect to the opening degree L of the back pressure presser, the first threshold value L1, the second threshold value L2, and the third threshold value L3 (L1 <L2 <L3) are set. The first threshold value L1 is a value determined so that sludge having poor dehydration does not knead, and the third threshold value is a value defined so that sludge having good dehydration is not excessively dehydrated. Further, the maximum torque SH allowed for the electric motor (screw shaft) is set.

始動ステップでは、スクリュー軸の回転数が設定値（本実施形態では０．２〜０．５ｒｐｍ程度）となるように電動モータを起動するとともに、プレッサ圧が標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧（本実施形態では上限値ＰＨ）となるようにエアシリンダーを制御し（Ｓ０）、その状態が所定時間Ｔ１（本実施形態では、スクリュー軸が０．３ｒｐｍで約３０分）維持される（Ｓ１）。 In the starting step, the electric motor is started so that the rotation speed of the screw shaft becomes a set value (about 0.2 to 0.5 rpm in this embodiment), and the presser pressure is higher than the standard value PO and below the upper limit value PH. The air cylinder is controlled to reach the set initial presser pressure (upper limit pH in this embodiment) (S0), and the state is T1 for a predetermined time (in this embodiment, the screw shaft is about 30 minutes at 0.3 rpm). It is maintained (S1).

初期プレッサ圧調整ステップでは、所定時間Ｔ１経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐが増減調整される。背圧プレッサの開度Ｌが、予め設定された第１閾値Ｌ１未満であれば（Ｓ２）、プレッサ圧Ｐが下限値ＰＬに調整され（Ｓ４）、第１閾値Ｌ１を超えればプレッサ圧Ｐが標準値ＰＯに調整される（Ｓ３）。 In the initial presser pressure adjusting step, the presser pressure P is increased or decreased between the upper limit value PH and the lower limit value PL based on the opening degree of the back pressure presser after the elapse of the predetermined time T1. If the opening degree L of the back pressure presser is less than the preset first threshold value L1 (S2), the presser pressure P is adjusted to the lower limit value PL (S4), and if it exceeds the first threshold value L1, the presser pressure P increases. It is adjusted to the standard value PO (S3).

つまり、第１閾値Ｌ１を指標に脱水ケーキの脱水性が評価される。背圧プレッサの開度Ｌが第１閾値Ｌ１未満であれば脱水性が悪いと判断されて、プレッサ圧Ｐが下限値ＰＬに調整されることで排出不良の発生を未然に防ぎスクリューによる練り込みが回避される。背圧プレッサの開度Ｌが第１閾値Ｌ１を超えていれば脱水性が悪くないと判断されて、必要以上に含水率が低下しないようにプレッサ圧Ｐが標準値ＰＯに調整される。 That is, the dehydration property of the dehydrated cake is evaluated using the first threshold value L1 as an index. If the opening L of the back pressure presser is less than the first threshold value L1, it is judged that the dehydration property is poor, and the presser pressure P is adjusted to the lower limit value PL to prevent the occurrence of discharge failure and knead with a screw. Is avoided. If the opening degree L of the back pressure presser exceeds the first threshold value L1, it is determined that the dehydration property is not bad, and the presser pressure P is adjusted to the standard value PO so that the water content does not decrease more than necessary.

プレッサ開度維持ステップでは、初期プレッサ圧調整ステップの後に設定された所定時間Ｔ２（本実施形態ではスクリュー軸が２回転以上回転する５〜１０分程度の時間）経過後（Ｓ５）に、プレッサ圧Ｐが上限値ＰＨと下限値ＰＬの間で調整されることにより、背圧プレッサの開度Ｌが所定値または所定範囲に維持される。 In the presser opening maintenance step, the presser pressure is set after a predetermined time T2 (a time of about 5 to 10 minutes for the screw shaft to rotate two or more rotations in this embodiment) set after the initial presser pressure adjusting step (S5). By adjusting P between the upper limit value PH and the lower limit value PL, the opening degree L of the back pressure presser is maintained at a predetermined value or a predetermined range.

背圧プレッサの開度ＬがＬ１以下であれば（Ｓ６）、下限値ＰＬになるまでの間でプレッサ圧Ｐを予め設定された微小操作量ΔＰ下げて（Ｓ１３）、ステップＳ５に戻る。背圧プレッサの開度ＬがＬ１を超え（Ｓ６）、且つ、Ｌ２以下であれば（Ｓ７）、上限値ＰＨになるまでの間でプレッサ圧Ｐを予め設定された微小操作量ΔＰ上げて（Ｓ１４）、ステップＳ５に戻る。 If the opening degree L of the back pressure presser is L1 or less (S6), the presser pressure P is lowered by a preset minute operation amount ΔP (S13) until the lower limit value PL is reached, and the process returns to step S5. If the opening degree L of the back pressure presser exceeds L1 (S6) and is L2 or less (S7), the presser pressure P is increased by a preset minute operation amount ΔP until the upper limit value PH is reached (S7). S14), the process returns to step S5.

また、背圧プレッサの開度ＬがＬ２を超え（Ｓ７）、且つ、Ｌ３以下になると（Ｓ８）、プレッサ圧Ｐが標準値ＰＯを超えておれば（Ｓ１５）、プレッサ圧Ｐを予め設定された微小操作量ΔＰ下げて（Ｓ１７）、ステップＳ５に戻り、ステップＳ１５でプレッサ圧Ｐが標準値ＰＯ以下であれば、プレッサ圧Ｐを予め設定された微小操作量ΔＰ上げて（Ｓ１６）、ステップＳ５に戻る。 Further, when the opening degree L of the back pressure presser exceeds L2 (S7) and becomes L3 or less (S8), if the presser pressure P exceeds the standard value PO (S15), the presser pressure P is set in advance. Decrease the minute manipulation amount ΔP (S17), return to step S5, and if the presser pressure P is equal to or less than the standard value PO in step S15, increase the presser pressure P by the preset minute manipulation amount ΔP (S16), and then step. Return to S5.

さらに、背圧プレッサの開度ＬがＬ３を超えたときには（Ｓ８）、検出トルクＳが許容最大値より低ければ（Ｓ９）、プレッサ圧Ｐを標準値ＰＯに設定して（Ｓ１２）、ステップＳ５に戻る。 Further, when the opening degree L of the back pressure presser exceeds L3 (S8), if the detected torque S is lower than the maximum allowable value (S9), the presser pressure P is set to the standard value PO (S12), and step S5. Return to.

ステップＳ９で検出トルクＳが許容最大値以上のときには、プレッサ圧Ｐが標準値ＰＯ以下なら（Ｓ１０）、プレッサ圧Ｐを予め設定された微小操作量ΔＰ下げて（Ｓ１１）、ステップＳ５に戻り、プレッサ圧Ｐが標準値ＰＯを超えていれば（Ｓ１０）、プレッサ圧Ｐを標準値ＰＯに設定して（Ｓ１２）、ステップＳ５に戻る。 When the detection torque S is equal to or greater than the allowable maximum value in step S9, if the presser pressure P is equal to or less than the standard value PO (S10), the presser pressure P is lowered by a preset minute operation amount ΔP (S11), and the process returns to step S5. If the presser pressure P exceeds the standard value PO (S10), the presser pressure P is set to the standard value PO (S12), and the process returns to step S5.

つまり、プレッサ開度維持ステップは、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを第１閾値Ｌ１と第１の閾値Ｌ１より大きな値に設定された第２閾値Ｌ２との間に維持するように構成されることにより、脱水ケーキの含水率が適切な値で脱水されるようになる。 That is, in the presser opening maintenance step, the opening L of the back pressure presser is set to a value larger than the first threshold value L1 and the first threshold value L1 by adjusting the presser pressure P between the upper limit value PH and the lower limit value PL. By being configured to be maintained between the set second threshold value L2, the water content of the dehydrated cake is dehydrated at an appropriate value.

そして、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えるとプレッサ圧Ｐを標準値ＰＯに向けて調整されるので、脱水性が良く含水率が低い脱水ケーキの含水率が必要以上に低下しない。 When the opening degree L of the back pressure presser exceeds the second threshold value L2, the presser pressure P is adjusted toward the standard value PO, so that the water content of the dehydrated cake having good dehydration and low water content is lowered more than necessary. do not.

さらに、背圧プレッサの開度Ｌが第３閾値Ｌ３を超え、且つ、スクリュー回転トルクＳが予め設定された閾値ＳＨを超えるとプレッサ圧Ｐを下限値ＰＬに向けて調整することにより、脱水性が良く含水率が低い脱水ケーキの含水率が必要以上に低下し、さらには被圧搾物とスクリューとの供回りが発生するといった不都合な事態の発生が未然に回避される。 Further, when the opening degree L of the back pressure presser exceeds the third threshold value L3 and the screw rotation torque S exceeds the preset threshold value SH, the presser pressure P is adjusted toward the lower limit value PL, thereby dewatering. The water content of the dehydrated cake, which is good and has a low water content, is lowered more than necessary, and the occurrence of inconvenient situations such as the rotation of the pressed object and the screw is prevented.

以上説明したように、本発明によるスクリュープレス型脱水機の運転方法によれば、標準値ＰＯより高く上限値ＰＨ以下のある程度の高い初期プレッサ圧が付与された状態で起動される始動ステップが実行されて、その状態が所定時間継続されることにより機内圧力が上昇して早期に適切な脱水圧になるので、起動時に含水率の高いケーキの排出量が効果的に抑制される。そして所定時間後に初期プレッサ圧調整ステップが実行され、その時の背圧プレッサの開度に基づいて上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐが適切な値に調整されるので、脱水ケーキの排出不良が生じることなく含水率が適切に調整される。 As described above, according to the operation method of the screw press type dehydrator according to the present invention, the start step is executed in a state where a certain high initial presser pressure higher than the standard value PO and lower than the upper limit value PH is applied. Then, when the state is continued for a predetermined time, the in-flight pressure rises and the dehydration pressure becomes appropriate at an early stage, so that the discharge amount of the cake having a high water content is effectively suppressed at the time of starting. Then, after a predetermined time, the initial presser pressure adjusting step is executed, and the presser pressure P is adjusted to an appropriate value between the upper limit value PH and the lower limit value PL based on the opening degree of the back pressure presser at that time. The moisture content is adjusted appropriately without causing poor discharge.

上述した制御装置２０のうち、始動ステップ（Ｓ０，Ｓ１）を実行する機能ブロックにより、標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧で運転を開始する始動制御部が構成され、初期プレッサ圧調整ステップ（Ｓ２〜Ｓ４）を実行する機能ブロックにより、運転開始から所定時間経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐを調整する初期プレッサ圧調整制御部が構成される。 Among the control devices 20 described above, the functional block that executes the start step (S0, S1) constitutes a start control unit that starts operation with an initial presser pressure set higher than the standard value PO and below the upper limit PH value, and is initially set. The functional block that executes the presser pressure adjustment steps (S2 to S4) adjusts the presser pressure P between the upper limit PH and the lower limit PL based on the opening degree of the back pressure presser after a lapse of a predetermined time from the start of operation. The initial presser pressure adjustment control unit is configured.

さらに、制御装置２０のうち、プレッサ開度維持ステップ（Ｓ５〜Ｓ１７）を実行する機能ブロックにより、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを所定値または所定範囲に維持するプレッサ開度維持制御部が構成される。 Further, in the control device 20, the opening degree of the back pressure presser is adjusted by adjusting the presser pressure P between the upper limit value PH and the lower limit value PL by the functional block that executes the presser opening degree maintaining step (S5 to S17). A presser opening degree maintaining control unit for maintaining L within a predetermined value or a predetermined range is configured.

上述した実施形態では、二軸スクリュープレス型脱水機を例に本発明を説明したが、本発明の適用対象は二軸スクリュープレス型脱水機に限るものではなく、二軸以上の多軸スクリュープレス型脱水機や、一軸スクリュープレス型脱水機にも適用可能であることは言うまでもない。 In the above-described embodiment, the present invention has been described by taking a biaxial screw press type dehydrator as an example, but the application of the present invention is not limited to the biaxial screw press type dehydrator, and a multi-axis screw press having two or more axes Needless to say, it can also be applied to a type dehydrator and a uniaxial screw press type dehydrator.

また、プレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯ、スクリュー軸３，４の回転数（ｒｐｍ）、背圧プレッサの開度Ｌに関する第１閾値Ｌ１、第２閾値Ｌ２、第３閾値Ｌ３（Ｌ１＜Ｌ２＜Ｌ３）電動モータ（スクリュー軸）に許容される最大トルクＳＨの具体的な数値は、特に限定されるものではなく、被圧搾物となる汚泥の大まかな性状に基づいて、脱水ケーキの含水率が目標値になるように、そして脱水処理量（ｋｇ−ＤＳ／ｈ）が目標処理量となるように適宜設定される値である。 Further, it relates to the upper limit value PH and the lower limit value PL of the presser pressure P, the standard value PO between the upper limit value PH and the lower limit value PL, the rotation speed (rpm) of the screw shafts 3 and 4, and the opening degree L of the back pressure presser. The specific numerical values of the maximum torque SH allowed for the first threshold L1, the second threshold L2, and the third threshold L3 (L1 <L2 <L3) electric motor (screw shaft) are not particularly limited and are subject to. A value appropriately set so that the water content of the dehydrated cake becomes the target value and the dehydration treatment amount (kg-DS / h) becomes the target treatment amount based on the rough properties of the sludge to be pressed. Is.

上述したスクリュープレス型脱水機の各部の具体的構成は実施形態の記載に限定されるものではなく、本発明による作用効果を奏する範囲において適宜変更設計可能であることはいうまでもない。 It goes without saying that the specific configuration of each part of the screw press type dehydrator described above is not limited to the description of the embodiment, and can be appropriately modified and designed within the range in which the action and effect according to the present invention are exhibited.

１：基台
２：外胴スクリーン
３，４：スクリュー軸
３ａ，４ａ：スクリュー羽根
５：背圧プレッサ
６：エアシリンダー
７：駆動装置
１０：スクリュープレス型脱水機
２０：制御装置
1: Base 2: Outer body screens 3, 4: Screw shafts 3a, 4a: Screw blades 5: Back pressure presser 6: Air cylinder 7: Drive device 10: Screw press type dehydrator 20: Control device

Claims (12)

スラリーを脱水するためのスクリュープレス型脱水機の運転方法であって、
汚泥性状に基づいて予め設定されたプレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯに対して、標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧で運転を開始する始動ステップと、
前記始動ステップから前記初期プレッサ圧を保持して所定時間経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐを調整する初期プレッサ圧調整ステップと、
を備えている、スクリュープレス型脱水機の運転方法。 A method of operating a screw press type dehydrator for dehydrating a slurry.
The upper limit PH, lower limit PL, and standard value PO between the upper limit PH and lower limit PL of the presser pressure P preset based on the sludge properties are higher than the standard value PO and lower than the upper limit PH. The starting step to start operation with the set initial presser pressure,
An initial presser pressure adjusting step that holds the initial presser pressure from the starting step and adjusts the presser pressure P between the upper limit value PH and the lower limit value PL based on the opening degree of the back pressure presser after a lapse of a predetermined time.
How to operate a screw press type dehydrator equipped with. 前記初期プレッサ圧調整ステップにおいて、前記所定時間経過後の背圧プレッサの開度Ｌが、予め設定された第１閾値Ｌ１未満であればプレッサ圧Ｐを下限値ＰＬに調整し、第１閾値Ｌ１を超えればプレッサ圧Ｐを標準値ＰＯに調整する、請求項１記載のスクリュープレス型脱水機の運転方法。 In the initial presser pressure adjusting step, if the opening degree L of the back pressure presser after the lapse of the predetermined time is less than the preset first threshold value L1, the presser pressure P is adjusted to the lower limit value PL, and the first threshold value L1 The method for operating the screw press type dehydrator according to claim 1, wherein the presser pressure P is adjusted to the standard value PO if the pressure exceeds. 前記初期プレッサ圧調整ステップの後に、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを所定値または所定範囲に維持するプレッサ開度維持ステップを備えている、請求項１または２記載のスクリュープレス型脱水機の運転方法。 After the initial presser pressure adjusting step, a presser opening degree maintaining step for maintaining the back pressure presser opening degree L within a predetermined value or a predetermined range by adjusting the presser pressure P between the upper limit value PH and the lower limit value PL is performed. The method for operating the screw press type dehydrator according to claim 1 or 2, which is provided. 前記プレッサ開度維持ステップは、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを第１閾値Ｌ１と第１閾値Ｌ１より大きな値に設定された第２閾値Ｌ２との間に維持する、請求項３記載のスクリュープレス型脱水機の運転方法。 In the presser opening degree maintaining step, the opening degree L of the back pressure presser is set to a value larger than the first threshold value L1 and the first threshold value L1 by adjusting the presser pressure P between the upper limit value PH and the lower limit value PL. The method for operating the screw press type dehydrator according to claim 3, which is maintained between the second threshold value L2 and the second threshold value L2. 前記プレッサ開度維持ステップにおいて、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えるとプレッサ圧Ｐを標準値ＰＯに向けて調整する、請求項４記載のスクリュープレス型脱水機の運転方法。 The method for operating a screw press type dehydrator according to claim 4, wherein in the step of maintaining the opening degree of the presser, when the opening degree L of the back pressure presser exceeds the second threshold value L2, the presser pressure P is adjusted toward the standard value PO. 前記プレッサ開度維持ステップにおいて、背圧プレッサの開度Ｌが第２閾値Ｌ２を超え、且つ、スクリュー回転トルクＳが予め設定された閾値ＳＨを超えるとプレッサ圧Ｐを下限値ＰＬに向けて調整する、請求項４記載のスクリュープレス型脱水機の運転方法。 In the presser opening degree maintaining step, when the opening degree L of the back pressure presser exceeds the second threshold value L2 and the screw rotation torque S exceeds the preset threshold value SH, the presser pressure P is adjusted toward the lower limit value PL. The method for operating the screw press type dehydrator according to claim 4. スラリーを脱水するためのスクリュープレス型脱水機の制御装置であって、
汚泥性状に基づいて予め設定されたプレッサ圧Ｐの上限値ＰＨ、下限値ＰＬ、および上限値ＰＨと下限値ＰＬの間にある標準値ＰＯに対して、標準値ＰＯより高く上限値ＰＨ以下に設定した初期プレッサ圧で運転を開始する始動制御部と、
運転開始から前記初期プレッサ圧を保持して所定時間経過後の背圧プレッサの開度に基づいて、上限値ＰＨと下限値ＰＬの間でプレッサ圧Ｐを調整する初期プレッサ圧調整制御部と、
を備えている、スクリュープレス型脱水機の制御装置。 A control device for a screw press type dehydrator for dehydrating slurry.
The upper limit PH, lower limit PL, and standard value PO between the upper limit PH and lower limit PL of the presser pressure P preset based on the sludge properties are higher than the standard value PO and lower than the upper limit PH. A start control unit that starts operation with the set initial presser pressure,
An initial presser pressure adjustment control unit that holds the initial presser pressure from the start of operation and adjusts the presser pressure P between the upper limit value PH and the lower limit value PL based on the opening degree of the back pressure presser after a lapse of a predetermined time.
The control device of the screw press type dehydrator equipped with. 前記初期プレッサ圧調整制御部は、前記所定時間経過後の背圧プレッサの開度Ｌが、予め設定された第１閾値Ｌ１未満であればプレッサ圧Ｐを下限値ＰＬに調整し、第１閾値Ｌ１を超えればプレッサ圧Ｐを標準値ＰＯに調整する、請求項７記載のスクリュープレス型脱水機の制御装置。 If the opening degree L of the back pressure presser after the elapse of the predetermined time is less than the preset first threshold value L1, the initial presser pressure adjustment control unit adjusts the presser pressure P to the lower limit value PL, and the first threshold value. The control device for a screw press type dehydrator according to claim 7, wherein the presser pressure P is adjusted to a standard value PO when L1 is exceeded. 前記初期プレッサ圧調整制御部による初期プレッサ圧調整制御の後に、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを所定値または所定範囲に維持するプレッサ開度維持制御部を備えている、請求項８または９記載のスクリュープレス型脱水機の制御装置。 After the initial presser pressure adjustment control by the initial presser pressure adjustment control unit, the back pressure presser opening degree L is maintained at a predetermined value or a predetermined range by adjusting the presser pressure P between the upper limit value PH and the lower limit value PL. The control device for a screw press type dehydrator according to claim 8 or 9, further comprising a presser opening degree maintaining control unit. 前記プレッサ開度維持制御部は、プレッサ圧Ｐを上限値ＰＨと下限値ＰＬの間で調整することにより、背圧プレッサの開度Ｌを第１閾値と第１の閾値Ｌ１より大きな値に設定された第２閾値Ｌ２との間に維持する、請求項９記載のスクリュープレス型脱水機の制御装置。 The presser opening degree maintenance control unit adjusts the presser pressure P between the upper limit value PH and the lower limit value PL to set the opening degree L of the back pressure presser to a value larger than the first threshold value and the first threshold value L1. The control device for a screw press type dehydrator according to claim 9, which is maintained between the second threshold value L2 and the threshold value L2. 前記プレッサ開度維持制御部は、背圧プレッサの開度Ｌが第２閾値Ｌ２を超えるとプレッサ圧Ｐを標準値ＰＯに向けて調整する、請求項１０記載のスクリュープレス型脱水機の制御装置。 The control device for a screw press type dehydrator according to claim 10, wherein the presser opening degree maintaining control unit adjusts the presser pressure P toward a standard value PO when the opening degree L of the back pressure presser exceeds the second threshold value L2. .. 前記プレッサ開度維持制御部は、背圧プレッサの開度Ｌが第２閾値Ｌ２を超え、且つ、スクリュー回転トルクＳが予め設定された閾値ＳＨを超えるとプレッサ圧Ｐを下限値ＰＬに向けて調整する、請求項１０記載のスクリュープレス型脱水機の制御装置。 When the opening degree L of the back pressure presser exceeds the second threshold value L2 and the screw rotation torque S exceeds the preset threshold value SH, the presser opening degree maintaining control unit directs the presser pressure P toward the lower limit value PL. The control device for a screw press type dehydrator according to claim 10, which is adjusted.
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