JP2014155894A - Centrifuge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifuge capable of reducing power consumption required for the driving of the centrifuge by suppressing the power consumption by preventing that separated water discharged from a bowl acts as resistance to the rotation of the bowl.SOLUTION: A centrifuge comprises: a bowl 106 to perform the solid-liquid separation of sludge to be treated; a separated water discharge port 112 located at the end wall 110a of the one end side of the bowl 106; a dewatered cake discharge port 113 located at another end of the bowl 106; a screw conveyor 109 to transport a dewatered cake K on the inner peripheral surface of the bowl 106; and a housing 114 covering the bowl 106. A cover member 114a is located between the outer surface of the end wall 110a of the bowl 106 and the inner surface of the housing 114. In the cover member 114a, an outer side region in a bowl radial direction from the separated water discharge port 112 in the outer surface of the end wall 110a of the bowl 106 is separated from a separated water discharging space E.

Description

  The present invention relates to a centrifuge and relates to a technique for suppressing interference between a bowl and separated water after discharge.

2. Description of the Related Art Conventionally, there are centrifuges such as a centrifugal dehydrator and a centrifugal concentrator as apparatuses for treating sludge generated in a sewage treatment process, for example.
The centrifugal dehydrator rotates the sludge at a high speed to separate the sludge content and the water by the specific gravity difference and dehydrate them. For example, there are those shown in FIGS.
[Constitution]
In this centrifugal dehydrator, the main structural member 1 is installed on the installation floor 2 of the building via the vibration isolating rubber 3, and the dehydrating main body portion 4 disposed on the main structural member 1 is a bearing portion 5a, It is supported by 5b.

  The dewatering main body 4 has a cylindrical bowl 6 and an inner cylinder 7 disposed inside the bowl 6 in a concentric manner. The rotation shafts 6 a and 6 b at both ends of the bowl 6 in the rotation axis direction, and the inner cylinder The rotation shaft portions 7a and 7b at both ends in the direction of the rotation axis 7 are rotatably supported, and the bowl 6 and the inner cylinder 7 arranged concentrically can rotate around the same rotation axis.

  The inner trunk 7 has blades 8 spirally provided around the rotation axis on the outer peripheral surface to constitute a screw conveyor 9. The bowl 6 has a straight body portion 10 at one end side in the direction of the rotation axis and a cone portion 11 that tapers toward the bowl end portion at the other end side. The straight body 10 mainly forms a separated water region where the separated water W of the separated water stays, and a plurality of separated water drains are disposed on the end wall 10a on one end side in the rotation axis direction of the straight body 10. The outlets 12 are arranged at equal distances from the rotation axis and at predetermined intervals around the rotation axis. As shown in FIG. 5, a dam plate (dam plate) 12 a is mounted on each separated water discharge port 12 so that the position of the dam plate 12 a in the radial direction of the bowl 6 can be adjusted. By adjusting, the weir height in the separated water discharge port 12 which becomes the upper limit water level of the separated water W in the bowl 6 is set.

  The cone portion 11 mainly forms a dehydrated cake region portion for transferring the dewatered cake K of the separated sludge. A plurality of dehydrated cake discharge ports 13 are centered on the rotation axis on the peripheral wall on the other end side of the cone portion 11. Are arranged at predetermined intervals around the rotation axis.

  The dewatering main body 4 is configured such that the inner drum 7 rotates at a predetermined differential speed with respect to the bowl 6, that is, with a difference in the number of rotations, and the screw conveyor 9 removes the dewatered cake K on the inner peripheral surface of the bowl 6. Transfer toward the other end.

  The housing 14 disposed so as to cover the dewatering main body 4 is fixed to the main structural member 1 and has a separated water discharge port 15 that opens downward at a portion surrounding the separated water discharge port 12 of the straight body portion 10. In addition, a dehydrated cake discharge port 16 opening downward is provided at a portion surrounding the dehydrated cake discharge port 13 of the cone portion 11.

  A main driving pulley 17 that rotationally drives the bowl 6 is provided on the rotary shaft portion 6a on the side of the straight body portion 10 supported by one bearing portion 5a, and the main driving pulley 17 is a driving motor (not shown). ). A reduction gear 18 is connected to the rotation shaft 7b of the inner cylinder 7 passing through the rotation shaft portion 6b on the cone portion 11 side supported by the bearing portion 5b, and a differential speed driving pulley 19 is connected to the input shaft 18a of the reduction gear 18. The differential speed driving pulley 19 is connected to a driving motor (not shown).

  The sludge supply pipe 20 is inserted into the inner cylinder 7 through the rotary shaft portion 6a on the straight body portion 10 side supported by the bearing portion 5a, and the tip opening 20a is a sludge input portion of the inner cylinder 7. It faces 21 wall surfaces. The chemical supply pipe 22 is inserted into the sludge supply pipe 20, and the tip opening 22 a faces the wall surface of the sludge inlet 21 of the inner trunk 7.

A plurality of sludge inlets 21a that open toward the inside of the straight body 10 are provided at radial positions around the rotation axis at predetermined intervals around the rotation axis. Is arranged in.
[Action]
The raw sludge S is supplied through the sludge supply pipe 20 to the sludge input section 21 of the inner cylinder 7 that rotates at high speed, and the polymer flocculant C is supplied through the chemical supply pipe 22 to the sludge input section 21 of the inner cylinder 7 that rotates at high speed. The mixed sludge of the raw sludge S and the polymer flocculant C is introduced into the bowl 6 rotating at high speed from the sludge inlet 21a of the sludge inlet 21.

  The mixed sludge containing sludge floc F aggregated inside the bowl 6 is solid-liquid separated into separated water W and dehydrated cake K by centrifugal force. The screw conveyor 9 having a slight rotational speed difference (differential speed) with the bowl 6 transfers the dehydrated cake K to the cone portion 11, and the moisture content of the dehydrated cake K further decreases during the movement of the cone portion 11. The product is discharged from the discharge port 13 to the inside of the housing 14 and discharged from the dewatered cake discharge port 16 to the outside of the machine.

The separated water W is discharged from the separated water discharge port 12 of the straight body portion 10 through the dam plate 12a to the inside of the housing 14 and discharged from the separated water discharge port 15 to the outside of the machine.
As another centrifugal dewatering device, there is one described in Patent Document 1, which is a straight barrel centrifugal dewatering device, in which the outer peripheral surface of the rotary drum of the screw conveyor is inclined in a large diameter direction from the straight portion and the straight portion. And has an inorganic flocculant supply path for supplying an inorganic flocculant to the inner peripheral surface of the straight part of the rotary drum, and the straight part is connected to the inorganic flocculant supply path for adding an inorganic flocculant. And an inorganic flocculant addition nozzle protruding into the annular space of the orifice and the bowl.

JP 2012-187570 A

  However, in the configuration shown in FIGS. 4 to 6, the separated water W discharged into the housing 14 from the separated water discharge port 12 of the straight body portion 10 is subjected to centrifugal force and diffused around the rotation axis. A water resistance region is formed in which the space between the housing 14 and the end surface and the outer peripheral surface of the straight body portion 10 is filled with scattered water.

  The separation water W in the water resistance region adheres to or collides with the end surface and the outer peripheral surface of the straight body portion 10 at the boundary between the end surface of the straight body portion 10 and the outer peripheral surface of the end portion and the water resistance region. Thus, the separated water becomes a resistance against the rotation of the bowl 6 and the power consumption required for the rotation of the bowl 6 increases.

  The present invention solves the above-mentioned problems, and prevents the separated water discharged from the bowl from acting as a resistance against the rotation of the bowl, thereby suppressing the power consumption and the power consumption required for driving the centrifuge. It aims at providing the centrifuge which can reduce quantity.

  In order to solve the above problems, a centrifugal separator according to the present invention includes a bowl that rotates around a rotation axis to separate the sludge to be treated into separated water and dehydrated cake by centrifugal force, and a direction of the rotation axis of the bowl The separated water discharge port provided on the end wall on one end of the bowl, the dewatered cake discharge port provided on the other end side in the rotation axis direction of the bowl, and the inside of the bowl rotating around the rotation axis in the bowl A screw conveyor for transferring the dewatered cake toward the dewatered cake discharge port on the peripheral surface, and a housing arranged so as to cover the bowl, and a cover member is provided between the outer surface of the end wall of the bowl and the inner surface of the housing A separation water drainage space is formed between the cover member and the inner surface of the housing, and the cover member separates the outer region in the radial direction of the bowl from the separation water discharge port on the outer surface of the end wall of the bowl from the separation water drainage space. It is characterized by.

  In the centrifuge of the present invention, a dam plate for setting an upper limit water level in the bowl is disposed so as to cover a part of the opening of each separation water discharge port, and the dam plate projects over the overflow edge forward in the flow direction. It has the part.

The centrifuge of the present invention is characterized in that the collar portion protrudes so as to hang over the inner peripheral edge of the cover member.
In the centrifuge of the present invention, the cover member extends to the outer peripheral surface of the bowl and spreads.

  As described above, according to the present invention, the separated water discharged from the separated water discharge port of the bowl to the inside of the housing is subjected to centrifugal force and diffused around the rotation axis, and the cover member and the inner surface of the housing are separated. The separated water drainage space is filled with scattered water.

  Since the cover member separates the outer area in the bowl radial direction from the separated water discharge port on the outer surface of the end wall of the bowl from the separated water drainage space, the separated water in the separated water drainage space adheres to the outer surface of the end wall of the bowl. Power that is required to drive the centrifuge by suppressing the power consumption required for the rotation of the bowl Can be reduced.

  In addition, since the dam plate has a flange portion that protrudes forward in the flow direction at the overflow edge, the separated water discharged from the separated water discharge port is reliably guided to the separated water drainage space, and the separated water is separated from the cover member and the bowl. Dissipation between the outer wall of the end wall can be prevented.

  In addition, the cover member extends and extends to the outer peripheral surface of the bowl, so that the separated water discharged from the bowl is reliably prevented from adhering to or colliding with the bowl, and power consumption required for driving the centrifuge is eliminated. The amount can be further reduced.

Sectional drawing which shows the centrifuge in embodiment of this invention Enlarged view showing the main part of the centrifuge The perspective view which shows the dam plate in the centrifuge Sectional view showing a conventional centrifuge Enlarged view showing the main part of the centrifuge The perspective view which shows the dam plate in the centrifuge

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. 1 to 3, a centrifugal dehydrator 100 includes a main structural member 101 installed on a building installation floor surface 102 via a vibration isolating rubber 103, and a dehydrating main body disposed on the main structural member 101. The portion 104 is supported by bearing portions 105a and 105b.

  The dewatering main body 104 has a cylindrical straight body-shaped bowl 106 and an inner body 107 disposed inside the bowl 106 concentrically, and the bearing portions 105a and 105b are rotation shafts at both ends of the bowl 106 in the rotational axis direction. Portions 106a and 106b are rotatably supported, and the bowl 106 rotatably supports the rotation shaft portions 107a and 107b at both ends of the inner cylinder 107 in the rotation axis direction. The body 107 can rotate around the same rotational axis.

The inner body 107 has blades 108 spirally provided around the rotation axis on the outer peripheral surface to constitute a screw conveyor 109.
The bowl 106 forms a separated water region 110 in which separated water W of water separated mainly at one end side in the direction of the rotation axis is retained, and the sludge dewatered cake K mainly separated at the other end side in the direction of the rotation axis. A dehydrated cake region portion 111 to be transferred is formed.

  A plurality of separated water discharge ports 112 are arranged on the end wall 110a at one end of the bowl 106 in the direction of the rotation axis at equal distances from the rotation axis and at predetermined intervals around the rotation axis. As shown in FIG. 2, a dam plate (dam plate) 112 a covers a part of the opening of each separated water discharge port and can be adjusted in the radial direction of the bowl 106 at each separated water discharge port 112. ing. As shown in FIG. 3, the dam plate 112 a has a flange 112 b that protrudes forward in the flow direction at the overflow edge, and by adjusting the position of the bowl 106 in the radial direction, the separated water W in the bowl 106. The weir height at the separated water discharge port 112 that is the upper limit water level is set. A plurality of dewatered cake discharge ports 113 are arranged on the peripheral wall on the other end side in the rotation axis direction of the bowl 106 at radial positions around the rotation axis and at predetermined intervals around the rotation axis.

  The inner cylinder 107 has a tapered shaft shape in which a portion corresponding to the other end of the bowl 106 approaches the other end of the inner cylinder 107 so that the inner cylinder diameter increases, and a dehydrated cake region between the inner cylinder 107 and the bowl 106 is formed. The portion 111 becomes narrower as it approaches the other end of the bowl 106, and a narrow path 106 c between the outer peripheral surface of the other end of the inner cylinder 107 and the inner peripheral surface of the other end of the bowl 106 is formed in the dehydrated cake region 111 and the dehydrated cake discharge port 113. Is communicated.

  In the dewatering main body 104, the inner cylinder 107 rotates at a predetermined differential speed with respect to the bowl 106, and the screw conveyor 109 transfers the dewatered cake K toward the other end of the bowl 106 on the inner peripheral surface of the bowl 106. The dehydrated cake K is pushed out from the dehydrated cake region 111 to the dehydrated cake discharge port 113 through the bottleneck 106c.

  The housing 114 disposed so as to cover the dewatering main body 104 is fixed to the main structural member 101, and has a separation water discharge port 115 that opens downward at a portion surrounding the separation water discharge port 112 of the separation water region 110. In addition, a dehydrated cake discharge port 116 opening downward is provided at a portion surrounding the dehydrated cake discharge port 113 of the dehydrated cake region 111.

  A hydraulic motor 118 is connected as a differential speed device to the rotating shaft portion 106b on the side of the dehydrated cake region portion 111 supported by the bearing portion 105b and the rotating shaft 107b of the inner cylinder 107 passing through the rotating shaft portion 106b. A drive motor of a drive source and a hydraulic pump (not shown) are connected to the motor.

  The sludge supply pipe 120 is inserted into the inner cylinder 107 through the rotating shaft part 106a on the separated water region part 110 side supported by the bearing part 105a, and the tip opening 120a is inserted into the sludge of the inner cylinder 107. It faces the wall surface of the part 121. The chemical supply pipe 122 is inserted into the sludge supply pipe 120, and the tip opening 122 a faces the wall surface of the sludge inlet 121 of the inner trunk 107.

  A plurality of sludge inlets 121a that open toward the inside of the separated water region 110 are provided at radial positions around the rotational axis and around the rotational axis on the peripheral wall of the sludge inlet 121 of the inner trunk 107. Arranged at intervals.

  A cover member 114 a is provided between the outer surface of the end wall 110 a on one end side in the rotational axis direction of the bowl 106 and the inner surface of the housing 114, and the cover member 114 a is supported by the housing 114. A separated water drainage space E is formed between the cover member 114a and the inner surface of the housing 114, and the cover member 114a extends from the separated water discharge port 112 on the outer surface of the end wall 110a of the bowl 106 to the outer area in the bowl radial direction. Is separated from the separated water drainage space E.

The cover member 114a is not limited to the shape shown in the present embodiment, and the outer area in the bowl radial direction is separated from the separated water drainage space E from the separated water discharge port 112 on the outer surface of the end wall 110a of the bowl 106. As long as it exhibits a function, it may extend to the outer peripheral surface of the bowl 106 and spread as shown in FIG.
[Action]
The raw sludge S is supplied through the sludge supply pipe 120 to the sludge input section 121 of the inner cylinder 107 that rotates at high speed, and the polymer flocculant C is supplied through the chemical supply pipe 122 to the sludge input section 121 of the inner cylinder 107 that rotates at high speed. The mixed sludge of the raw sludge S and the polymer flocculant C is introduced into the bowl 106 rotating at high speed from the sludge inlet 121a of the sludge inlet 121.

  The mixed sludge including the sludge floc F aggregated inside the bowl 106 is solid-liquid separated into separated water W and dewatered cake K by centrifugal force. The screw conveyor 109 having a rotational speed difference (differential speed) with the bowl 106 transfers the dehydrated cake K to the dehydrated cake area 111, and the moisture content of the dehydrated cake K further decreases while moving in the dehydrated cake area 111. It is discharged from the dehydrated cake discharge port 113 into the housing 114 and discharged from the dehydrated cake discharge port 116 to the outside of the machine.

  Separation water W discharged from the separated water discharge port 112 of the bowl 106 over the dam plate 112a and discharged into the housing 114 is subjected to centrifugal force and diffused around the rotation axis, so that the inner surface of the cover member 114a and the housing 114 The separated water drainage space E is filled with scattered water, and the separated water W is discharged from the separated water discharge port 115 to the outside of the apparatus.

  Since the cover member 114a separates the outer region in the bowl radial direction from the separated water discharge port 112 on the outer surface of the end wall 110a of the bowl 106 from the separated water drainage space E, the separated water W in the separated water drainage space E is It is less likely to adhere to or collide with the outer surface of the end wall 110a, and the separated water W discharged from the bowl 106 does not become a resistance to the rotation of the bowl 106, and the power consumption required for the rotation of the bowl 106 is reduced. The power consumption required for driving the centrifugal separator can be reduced.

  Further, since the dam plate 112a has the flange portion 112b that protrudes forward in the flow direction at the overflow edge, the separated water W discharged from the separated water discharge port 112 is reliably guided to the separated water drainage space E, and the separated water W Can be prevented from being diffused between the cover member 114a and the outer surface of the end wall 110a of the bowl 106.

  In addition, since the cover member 114a extends to the outer peripheral surface of the bowl 106, the separated water W discharged from the bowl 106 is reliably prevented from adhering to or colliding with the bowl 106. The power consumption required for driving can be further reduced.

  In the embodiment described above, the bowl 106 is illustrated as a straight body type, but it can also be a decanter type, and the screw conveyor 109 may be straight. Further, the sludge supply and the flocculant injection method are not limited to those disclosed in the present embodiment, and the injection direction can be reversed.

DESCRIPTION OF SYMBOLS 100 Centrifugal dehydrator 101 Main structural member 102 Installation floor surface 103 Anti-vibration rubber 104 Dehydration main body part 105a, 105b Bearing part 106 Bowl 106c Bottleneck 107 Inner trunk 107a, 107b Rotating shaft part 108 Blade 109 Screw conveyor 110 Separation water area part 110a End Section wall 111 Dehydrated cake area 112 Separation water discharge port 112a Dam plate 112b Saddle 113 Dewatering cake discharge port 114 Housing 114a Cover member 115 Separation water discharge port 116 Dehydrated cake discharge port 118 Hydraulic motor 120 Sludge supply pipe 120a Tip opening 121 Sludge Input part 121a Sludge inlet 122 Chemical supply pipe 122a Tip opening C Polymer flocculant S Raw sludge W Separated water K Dehydrated cake E Separated water drainage space

Claims (4)

A bowl that rotates around the rotation axis to separate the sludge to be treated into separated water and a dehydrated cake by centrifugal force; a separation water discharge port provided on an end wall on one end side of the bowl in the rotation axis direction; A dehydrated cake discharge port provided on the other end side in the direction of the rotation axis of the bowl and a rotation around the rotation axis in the bowl to transfer the dehydrated cake on the inner peripheral surface of the bowl toward the dehydration cake discharge port A screw conveyor and a housing arranged to cover the bowl,
A cover member is provided between the outer surface of the end wall of the bowl and the inner surface of the housing, and a separated water drainage space is formed between the cover member and the inner surface of the housing. The cover member is an outer surface of the end wall of the bowl. A centrifugal separator characterized in that the outer region in the bowl radial direction is separated from the separation water drainage space from the separation water discharge port in.   A dam plate for setting an upper limit water level in the bowl is disposed so as to cover a part of the opening of each separated water discharge port, and the dam plate has a flange portion protruding forward in the flow direction at the overflow edge. The centrifuge according to claim 1.   The centrifuge according to claim 1 or 2, wherein the flange portion extends so as to be hung on the inner peripheral edge of the cover member.   The centrifuge according to any one of claims 1 to 3, wherein the cover member extends and spreads on the outer peripheral surface of the bowl.

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