JPH0615199A - Centrifugal separator - Google Patents

Abstract

PURPOSE:To improve the dehydration rate of sludge by providing a cylindrical outer cylinder which rotates around its axial center, an inner cylinder which exists concentrically within this outer cylinder and rotates around its axial center and a discharge pipe which exists concentrically with the outer periphery of the inner cylinder integrally rotates with the inner cylinder, opens at one end annularly around the inner cylinder and communicates at the other end with the outside of the outer cylinder. CONSTITUTION:This centrifugal separator has the outer cylinder 12 which constitutes a cylindrical body, rotates around its axial center and forms a settling and separating part 12a, the inner cylinder 11 which exists concentrically within the outer cylinder 12 and rotates around its axial center and the discharge pipe 13 which exists concentrically with the outer periphery of the inner cylinder 11, integrally rotates with the inner cylinder 11, opens at one end annularly around the inner cylinder 11 and communicates at the other end with the outside of the outer cylinder 12. Namely, the sludge A is charged from a sludge supply pipe 15 into the outer cylinder in the state that the outer cylinder 12 and the inner cylinder 11 rotate at a high speed with a suitable rotation difference. The sludge A receives centrifugal force, by which the solid particles of a large sp. gr. are deposited on the inside wall of the setting and seperating part 12a. The sludge thus separated into two phases; a solid phase B and a liquid phase C. The liquid phase C overflows to the outside of the outer cylinder 12 through a discharge pipe 13.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a centrifuge used for treating tap water and sewage sludge.

[0002]

2. Description of the Related Art Conventionally, a centrifuge for separating solid and liquid has been used to treat sludge discharged from industrial wastewater and municipal sewage. The centrifuge includes a countercurrent type and a cocurrent type. .

A parallel flow type centrifugal dehydrator is, for example, shown in FIGS.
As shown in FIG. 1, the inner body 1 and the outer body 2 which rotate with a predetermined rotational speed difference are arranged coaxially, and the screw conveyor section 3 and the plurality of discharge pipes 4 are provided on the outer peripheral surface of the inner body 1. It was Then, the sludge A to which the polymer flocculant is added is supplied from the mud supply pipe 5 to the sedimentation separation section 2a of the outer case 2, and the sedimentation separation section 2 is supplied.
In a, the polymer flocculant and the sludge are mixed, and the centrifugal force acts on the solid particles and the liquid in the sludge sludge flocculated by the action of the polymer flocculant, so that the solid particles having a large specific gravity are deposited on the inner wall of the sedimentation separation section 2a. The solid phase B and the liquid phase C were separated into two phases.

Then, the solid phase B deposited on the inner wall of the settling / separating section 2a is conveyed to the liquid removing section 2b following the settling / separating section 2a by a screw conveyor section 3 provided around the inner case 1 and one end of the outer body 2 is conveyed. The liquid separated from the liquid phase C was allowed to flow from the other side of the outer shell 2 to the outside through the discharge pipe 4.

[0005]

In the above-mentioned conventional structure, the dehydration rate and SS recovery rate are improved by not disturbing the solid phase B and the liquid phase C in the sedimentation separation section 2a and the dewatering section 2b. It is a condition for. But,
As shown in FIG. 4, since the plurality of discharge pipes 4 are provided on the outer peripheral surface of the inner case 1, the discharge pipe 4 forms irregularities on the outer peripheral surface of the inner case 1, and the discharge pipes 4 are formed along with the inner case 1. When 4 rotates at high speed,
There was a problem that a turbulent flow was generated to disturb the solid phase B and the liquid phase C in the settling / separating section 2a and the liquid removing section 2b.

Further, since the inner case 1 rotates at high speed, it is necessary to arrange the discharge pipe 4 precisely in consideration of the balance of the center of gravity. Means for Solving the Problems The present invention solves the above problems, and can eliminate the occurrence of turbulence due to the discharge pipe, improve the recovery rate of SS and the dehydration rate of sludge, and have a good center of gravity balance and high speed rotation. An object of the present invention is to provide a centrifugal separator that can be used.

[0007]

In order to solve the above-mentioned problems, a centrifugal separator of the present invention comprises an outer cylinder forming a sedimentary separation portion, which forms a cylindrical body and rotates about an axis. An inner cylinder that is concentrically located inside and rotates about the axis, and is concentrically located on the outer circumference of the inner cylinder and rotates integrally with the inner cylinder, and one end opens annularly around the inner cylinder, The other end is provided with a discharge pipe communicating with the outside of the outer case.

[0008]

With the above construction, sludge is thrown into the outer case while the outer case and the inner case rotate at a high speed with an appropriate rotation difference. Sludge receives centrifugal force and deposits solid particles with a large specific gravity on the inner wall of the sedimentation separation part to separate it into two phases, a solid phase and a liquid phase, and the separated liquid forming the liquid phase opens in a ring around the inner shell. Overflow to the outside of the outer case through the discharge pipe.

At this time, since the discharge pipe is concentrically located on the outer circumference of the inner case, there is no unevenness in the direction along the outer peripheral surface of the inner case, and the solid phase and Since the liquid phase is not disturbed, the dehydration rate of sludge and the recovery rate of SS floating on the separated liquid are increased.

Further, since the discharge pipe is annularly opened to the outer periphery of the inner case, the opening area is greatly increased as compared with the conventional discharge pipe, and the suction speed of the separated liquid into the discharge pipe is suppressed to be low. The turbulence given to the liquid phase is reduced and the SS on the separated liquid
Can be widely captured, and a large amount of separated liquid can be discharged.

Further, since the discharge pipe is located concentrically on the outer circumference of the inner case, it has an excellent balance of the center of gravity and is stable even at high speed rotation.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, an inner case 11 having a tubular shape and an outer case 12 loosely fitted to the inner case 11 are rotatably arranged with their axes being horizontal. The inner case 11 and the outer case 12 are connected to a driving device (not shown), and the inner case 11 is the outer case 12
Rotate slightly less. The outer case 12 has a straight settling / separating section 12a and a liquid removing section 12b whose diameter is reduced toward the tip side, and the inner case 11 has a shape along the outer case 12.

Further, there is provided a discharge pipe 13 concentrically located on the outer periphery of the inner case 11 and rotating integrally with the inner case 11,
One end of the inner case 11 opens annularly around the inner case 11 at a position corresponding to the boundary between the settling / separating section 12a and the liquid removing section 12b, and the other end of the inner case 11 is directed toward the outside at the base end side of the outer case 12. It is open. A screw conveyor 14 that rotates integrally with the inner case 11 is provided on the outer peripheral portions of the inner case 11 and the discharge pipe 13. Further, a sludge supply pipe 15 is provided so as to be inserted into the inner case 11, and the sludge supply pipe 15 is opened at a plurality of locations on the outer peripheral surface of the discharge pipe 13.

The operation of the above structure will be described below.
The inner shell 11 and the outer shell 12 are rotated at a high speed with a small number of rotations, and the sediment separation section 12 is passed through the sludge supply pipe 15.
A sludge A having a flocculant added to a is supplied. Sedimentation and separation section 1
In 2a, the sludge A is subjected to centrifugal force, and is separated into a solid phase B of sludge particles and a liquid phase C of a separation liquid that are aggregated by the action of a coagulant.

Then, the solid phase B having a large specific gravity is deposited on the inner peripheral surface side of the settling / separating section 12a, and the scraping action of the screw conveyor section 14 rotating integrally with the inner case 11 causes the tip end side of the liquid removing section 12b. And is discharged to the outside from the tip side of the outer case 12. Further, the separated liquid of the liquid phase C flows out from the base end side of the outer case 12 to the outside through the discharge pipe 13 which is annularly opened around the inner case 11.

In the above-mentioned operation, the discharge pipe 13 is connected to the inner case 1.
Since it is located concentrically on the outer periphery of No. 1, there is no unevenness in the direction along the outer peripheral surface of the inner case 11, and the solid phase B and the liquid phase C are disturbed by the rotation of the inner case 11 and the discharge pipe 13. Since it is not given, the dehydration rate of sludge and the recovery rate of SS floating on the separated liquid are increased.

Further, since the discharge pipe 13 is annularly opened on the outer circumference of the inner case 11, the opening area is greatly increased as compared with the conventional discharge pipe 13, and the suction speed of the separated liquid into the discharge pipe 13 is increased. It is possible to suppress it to a low level to reduce the turbulence given to the liquid phase C, to widely capture SS on the separated liquid, and to discharge a large amount of the separated liquid.

Further, since the discharge pipe 13 is located concentrically on the outer periphery of the inner case 11, the balance of the center of gravity is excellent,
It is stable even at high speeds.

[0019]

As described above, according to the present invention, since the discharge pipe is concentrically located on the outer circumference of the inner barrel, the solid phase and the liquid phase are not disturbed by the rotation of the inner barrel and the discharge pipe. It is possible to improve the dehydration rate of sludge and the recovery rate of SS floating on the separated liquid. Since the discharge pipe is opened in an annular shape on the outer circumference of the inner body and the opening area is increased, the suction speed of the separation liquid is suppressed to reduce turbulence, and SS on the separation liquid can be widely captured. Can be discharged in large quantities, has a good center of gravity balance, and is stable even at high speeds.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a centrifuge showing an embodiment of the present invention.

FIG. 2 is a view taken along the line YY in FIG.

FIG. 3 is a schematic explanatory diagram of a conventional centrifuge.

FIG. 4 is a view on arrow XX in FIG.

[Explanation of symbols]

 11 Inner Body 12 Outer Body 12a Deliquor Part 12b Sedimentation Separation Part 13 Discharge Pipe 14 Screw Conveyor Part 15 Sludge Supply Pipe

Claims (1)

[Claims] 1. An outer cylinder which forms a cylindrical body and rotates about an axis to form a sedimentation separation portion, and an inner cylinder which is concentrically located inside the outer cylinder and rotates about an axis. It is concentrically located on the outer circumference of the body and rotates integrally with the inner body, and has one end open in a ring shape around the inner body and the other end with a discharge pipe communicating with the outside of the outer body. And centrifuge.