JP2012024742A - Centrifugal separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separator capable of continuously carrying out centrifugation without accumulating almost no sludge in a separation barrel during centrifugation.SOLUTION: The centrifugal separator comprises a separation barrel 7 which is provided rotatably, has openings at both upper and lower ends, and has inverted cone-like parts that are successively formed within an approximately cylindrical barrel part and the lower part thereof, a rotational driving means M for rotating the separation barrel 7, and an inflow means 6 that is provided through the opening of the upper end part of the separation barrel 7 for discharging a fluid to be treated toward the inner wall surface of the separation barrel 7. The rotational driving means M performs centrifugal rotation of the separation barrel 7, so as to discharge a fluid to be treated toward the inner wall surface. The fluid is thus separated into a separation solution and sludge S. At the same time, the separation solution is spun up along the inner wall surface of the separation barrel 7 so as to be discharged from the opening of the upper end part and thus the separated sludge S is spun down and discharged from the opening of the lower end part of the separation barrel 7.

Description

  The present invention relates to a centrifuge for centrifuging a fluid to be treated such as muddy water.

  Conventionally, a centrifuge that centrifuges water to be treated by centrifugation is known.

  The centrifugal separator of Patent Document 1 includes a separation cylinder that is rotatably provided and has a cylindrical shape with a U-shaped radial cross section that is open at both ends, and a supply nozzle that feeds water to be treated, which is muddy water, into the separation cylinder. ing. And if to-be-processed water is made to flow in into the inner wall surface of the rotating separation cylinder, it will be centrifuged so that it may become a liquid and a solid order from the inner side of a separation cylinder to the outer side by centrifugation.

  Here, as the amount of solid on the outside increases, the inner liquid level moves further inward, and the separated liquid overflows from the upper end opening. Further, when the solid sludge accumulated on the inner wall surface of the separation cylinder exceeds a predetermined amount, a pair of scraping blades provided so as to be rotatable coaxially with the separation cylinder and movable in the axial direction is separated. The sludge adhered to the inner wall surface of the separation cylinder is scraped off and discharged from the lower end opening of the separation cylinder.

  For example, in the field of civil engineering, when excavating the ground by rotating a drilling bucket, the hole is filled with a stable liquid mixed with bentonite or the like to protect the hole wall, Muddy water generated by mixing sludge such as sand with the stable liquid is sucked up and collected from the excavation hole by a pump, etc., and then centrifuged into a stable liquid and sludge using a centrifuge, and reused as a stable liquid again. is doing.

JP-A-8-117640

  However, in Patent Document 1, the sludge that has been separated and settled is not continuously discharged, and the operation must be interrupted occasionally in order to remove the sludge accumulated on the inner wall surface of the separation cylinder by centrifugation. I must.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a centrifuge that can be operated continuously with little sludge accumulating in the separation cylinder during centrifugation.

  In order to achieve the above object, a centrifuge according to the present invention is a centrifuge for centrifuging a fluid to be treated including sludge. The centrifuge is rotatably provided and has openings at both upper and lower ends, and has a substantially cylindrical body. A separation cylinder having an inverted conical portion formed continuously at the bottom of the body, rotation driving means for rotating the separation cylinder, and an opening at the upper end of the separation cylinder, Inflow means for discharging the fluid toward the inner wall surface of the separation cylinder, and the fluid to be treated discharged toward the inner wall surface by the centrifugal rotation of the separation cylinder by the rotation driving means is separated liquid and sludge. And the separated liquid rises along the inner wall surface of the separation cylinder and is discharged from the opening at the upper end, and the separated sludge descends from the opening at the lower end of the separation cylinder. It is characterized by being discharged.

  The sludge here refers to the separation target contained in the fluid to be treated, and mainly indicates pebbles and sand in the muddy water, but also includes clay and solid waste in the washing liquid. Further, the inverted conical shape portion may have a smooth surface portion.

  Further, the inflow means may be configured to discharge the fluid to be processed in a direction following a rotation direction of centrifugal separation of the separation cylinder.

  Furthermore, the smooth surface portion can be formed of at least a part of the inner peripheral wall of the separation cylinder with ethylene tetrafluoride.

  Further, the fluid to be treated may include bentonite, and the bentonite may be recovered in a state of being contained in the separation liquid by the separation.

  Furthermore, it can be set as the structure by which the said separation cylinder was provided so that attachment or detachment was possible.

  The rotation driving means may have a control means capable of adjusting the number of rotations of the separation cylinder.

  According to the centrifuge of the present invention configured as described above, the centrifuged sludge is lowered and continuously discharged from the opening at the lower end of the separation cylinder. Therefore, it is necessary to separately remove the sludge. Therefore, continuous separation processing is possible.

  Moreover, by providing a smooth surface portion on the inverted conical shape portion, it is possible to further make the sludge descend toward the opening at the lower end portion.

  In addition, by causing the fluid to be treated to flow in a direction that follows the direction of centrifugal rotation of the separation cylinder, the centrifugal force that contributes to the separation is increased and the centrifugal separation can be performed efficiently.

  Furthermore, since at least a part of the inner peripheral wall of the separation cylinder is made of tetrafluoroethylene, the smooth surface portion can be a smooth surface that is highly durable and hardly damaged.

  The treated fluid contains bentonite, and if the bentonite is recovered in the state of being contained in the separated liquid by the separation, the recovered separated liquid is used as a stabilizing liquid for protecting the inner wall of the excavation hole during excavation. Since it can be used, the muddy water collected from the excavation hole can be continuously regenerated and circulated again as a stable liquid for excavation to the excavation hole, so even one centrifuge can cope with continuous excavation.

  Furthermore, by making the separation cylinder detachable and replaceable, the separation cylinder can be easily replaced with a separation cylinder having an inverted conical portion having an angle suitable for the fluid to be treated or sludge.

  Further, if the rotation driving means has a control means capable of adjusting the rotation speed of the separation cylinder, the rotation speed can be adjusted to the optimum separation rotation speed for separation of the fluid to be treated.

The sectional view of the centrifugal separator according to the embodiment of the present invention shows the structure of the centrifugal separator and the movement of the separation liquid and sludge during the centrifugal separation. FIG. 2 is a partial cross-sectional view of the centrifuge as viewed in the direction of the arrow KK in FIG. It is a figure explaining the effect | action at the time of centrifugation.

  FIG. 1 shows a cross-sectional view of a centrifuge 1 according to the present invention.

As shown in FIG. 1, the centrifuge 1 includes a cylindrical separation cylinder 7 that is rotatably provided and has openings at both ends, and a rotation driving unit that rotates the separation cylinder 7. Motor M, and an inflow nozzle 6 as an inflow means for injecting muddy water as a fluid to be treated including sludge S into the separation cylinder 7.
<Case>
The casing 4 is for connecting the separation cylinder 7 and the motor M. The through holes 4a and 4b for installing the separation cylinder, the hole 4c for installing the motor, and the rotation of the separation cylinder provided in the through hole 4a. A bearing bearing portion 5A for the outer ring for support, a cylindrical case portion 2 standing from the outline of the through hole 4a on the upper surface 4d of the housing 4, and an upper cover 3 for closing the upper end opening of the cylindrical case portion 2 are provided. is doing. The through holes 4a and 4b of the housing 4 are provided with outer ring bearing bearing portions 5A and 5B for rotating and supporting the separation cylinder 7, respectively.
<Cylinder case>
The cylindrical case portion 2 has a large-diameter cylindrical portion 2A and a small-diameter cylindrical portion 2B, and a blind flange portion 2b protruding upward is formed on a step surface 2C between them. Further, a separation liquid discharge port 2a is formed on the step surface 2C, and a drain hose 15 is attached. The separation liquid discharge port 2a is connected to, for example, a tank (not shown) that supplies the separation liquid to the excavation hole.

  A nozzle insertion hole 3a is formed at the center of the upper cover 3, and a part of the inflow nozzle 6 for supplying muddy water to the separation surface 9 of the separation cylinder 7 described later is inserted and fixed. The front end portion 6a of the inflow nozzle 6 is disposed above a smooth surface portion 9 inside the separation cylinder 7 to be described later, and is bent and formed in a direction following the rotation direction A of the separation cylinder 7 (see FIG. 2).

The tip 6a of the inflow nozzle 6 discharges muddy water toward the inner wall surface of the jacket 8 described later. The other end of the inflow nozzle 6 is connected to a pump (not shown) that sucks up muddy water from the excavation hole.
<Separation cylinder>
The separation cylinder 7 serves to separate the muddy water containing the sludge S into a clarified liquid (separated liquid) and the sludge S during centrifugal rotation. The separation cylinder 7 includes a jacket section 8 having both ends open and a substantially cylindrical trunk section and a reverse truncated cone-shaped bottom section, and a funnel-shaped smooth surface section 9 disposed coaxially on the bottom inner wall surface of the jacket section 8. And a hollow drive shaft portion 10 extending downward from the bottom portion of the jacket portion 8.

  Here, the inverted conical portion is formed by the bottom portion of the truncated cone shape of the jacket portion 8 and the smooth surface portion 9. Further, the inside of the drive shaft portion 10 and the inside of the jacket portion 8 communicate with each other through the lower end opening of the smooth surface portion 9.

  The inner peripheral surface 9a of the funnel-shaped smooth surface portion 9 is a smooth surface to which the sludge S separated from the muddy water is difficult to adhere. The smooth surface portion 9 is formed of a material that can form a smooth surface and does not adversely affect the separation. For example, the smooth surface portion 9 is made of a fluororesin (such as tetrafluoroethylene).

  The smooth surface portion 9 is integrally fixed to the jacket portion 8 and is configured to rotate together with the jacket portion 8. Further, the lower end portion of the smooth surface portion 9 protrudes from the jacket portion 8 into the drive shaft portion 10.

  An inner flange portion 8b that is slightly larger than the outer shape of the blind flange portion 2b of the cylindrical case portion 2 is formed on the outer peripheral surface of the jacket portion 8, and covers the blind flange portion 2b from above in a non-contact state.

  As a result, the flange portion 8b serves as a baffle so that the separated liquid that has overflowed the upper end of the jacket portion 8 during centrifugation does not leak into the gap between the jacket portion 8 and the small-diameter cylindrical portion 2B of the cylindrical case portion 2. (See FIGS. 1 and 2). Further, since the flange portion 8b is separated from the blind flange portion 2b, the rotation of the separation cylinder 7 is not hindered.

  On the other hand, on the outer peripheral wall of the drive shaft portion 10, bearing bearing portions 10a, 10b for the inner ring in the axial direction and bearing bearing portions 10c for the inner ring in the radial direction are provided at a predetermined interval.

  The separation cylinder 7 is rotatably supported by the housing 4 by the housing 4 as a bearing, the bearing bearing portions 10a to 10c, 5A, and 5B of the drive shaft portion 10 and the rolling elements 14 therebetween.

  Further, a pulley 10d for rotational driving is formed integrally with the drive shaft portion 10 between the bearing bearing portions 10b and 10c. The pulley 10d and the rotating portion MP of the motor M mounted on the housing 4 are formed. Are connected by endless belts 12 and 12. Thereby, rotational power is transmitted from the motor M so that the separation cylinder 7 rotates.

  The motor M has a control means (not shown), can control the motor rotation speed, and can be set to a rotation speed suitable for muddy water separation. For example, the motor rotation speed is set to a rotation speed at which muddy water containing bentonite and sludge S can be separated into a separation liquid containing bentonite and sludge S.

As shown in FIG. 3, the angle b of the corner portion KD of the separation cylinder 7 is formed as an obtuse angle, and the inclination angle a of the smooth surface portion 9 and the rotational speed of the motor M are the gravitational force (sliding-down force) of pebbles and sand. Is a rotational speed and an inclination angle a (an angle with respect to a horizontal plane) that exceeds the component force (force that runs up) caused by the centrifugal force of sand or pebbles.
<Sludge discharge pipe>
As shown in FIG. 1, the sludge discharge pipe 11 is for receiving the sludge S coming out from the lower end opening of the smooth surface portion 9 at the time of centrifugal separation and discharging it to the outside of the centrifugal separator 1. Placed in.

  The sludge discharge pipe 11 includes a fixed portion 11a that is screwed and detachably fixed to the bearing bearing portion 5B of the housing 4, and a discharge pipe portion 11b that extends into the drive shaft portion 10 continuously to the fixed portion 11a. And a funnel-shaped sludge receiving portion 11c formed continuously at the upper end of the discharge pipe portion 11b.

  The funnel-shaped sludge receiving portion 11c is disposed slightly below the lower end of the smooth-surfaced smooth surface portion 9 so as not to receive centrifugal rotation power transmission from the separation cylinder 8. Further, since the sludge receiving portion 11c is arranged so as to cover the lower end portion of the smooth surface portion 9 slightly below, the sludge S from the lower end opening of the smooth surface portion 9 is in the gap between the smooth surface portion 9 and the sludge discharge pipe 11. It is hard to get in.

  Further, since the other part of the sludge discharge pipe 11 is also separated from the separation cylinder 7, the power transmission of centrifugal rotation is not received from the separation cylinder 7.

  Hereinafter, the operation of the centrifuge 1 will be described.

  As shown in FIGS. 1 and 2, in a state where the separation cylinder 7 is rotated by driving the motor M (see the white arrow A in FIG. 2), muddy water is transferred from the inflow nozzle 6 to the inner peripheral surface in the separation cylinder 7. When discharged (see the black thin arrow C in FIG. 2), the muddy water that has flowed in moves as a vortex on the inner peripheral surface (see the black thick arrow B in FIG. 2).

  At this time, the muddy water is separated into muddy water containing a large amount of clarified liquid (separated liquid) and muddy water containing a large amount of sludge S by centrifugal rotation. The former becomes an ascending vortex of the clarified liquid (separated liquid) containing almost no sludge S as the separation proceeds by further vortex rotation, and flows over the upper end opening of the jacket portion 8. The clarified liquid (separated liquid) that has overflowed flows into the drainage hose 15 from the separated liquid discharge port 2a and is discharged and collected. When the muddy water contains bentonite, the bentonite is contained in the clarified liquid and discharged to the drain hose 15 together as a separated liquid.

  On the other hand, the latter containing a large amount of sludge S descends to the smooth surface portion 9 as a descending vortex of a turbid liquid containing more sludge S as the separation further progresses by vortex rotation. Is separated (see FIG. 1), and the separated sludge S is discharged from the sludge discharge pipe 11 to the outside of the centrifuge 1 through the lower end opening of the smooth surface portion 9.

  In FIG. 3, the figure which expanded the corner | angular part KD of the separation cylinder 7 is shown, and the effect | action at the time of centrifugation is shown.

  That the smooth surface portion 9 has a funnel shape, in other words, that the angle of the corner KD is an obtuse angle, the separation liquid overflows the opening at the upper end of the separation cylinder 7 and the sludge S descends. To affect. That is, the sludge S is pressed against the inner wall by centrifugal force and becomes a part of the descending vortex, but a sludge S layer (hereinafter referred to as a sludge layer SL) is formed at the bottom of the descending vortex and the height increases. .

  Here, if the corner KD is a right angle, the thickness of the sludge layer SL must be increased without limit. However, the sludge layer SL has an obtuse angle because the angle b of the corner KD serving as the bottom of the sludge layer SL is obtuse. The layer SL is broken without being formed with a certain height or more, and at this time, the sludge S starts to move downward on the smooth surface portion 9. In addition, since this portion is a smooth surface, the sludge layer SL is more easily collapsed.

  In addition, a certain amount of this sludge layer SL at the corner KD always replaces the new sludge S that has flowed in, so that it becomes a weir for the downward movement of the separation liquid during centrifugation, and the liquid is at the upper end. It becomes a positive factor of overflowing the opening more. Since the centrifugal force is smaller toward the inside of the separation cylinder 7, the sludge S on the smooth surface portion 9 is immediately discharged, and the sludge S hardly accumulates on the smooth surface portion 9.

  Hereinafter, the operation and effect of the centrifuge 1 will be described.

  Since the tip 6a of the inflow nozzle 6 is bent so that the muddy water flows in a direction following the rotation direction of the separation cylinder 7, a strong vortex is generated and the centrifugal force contributing to the separation increases. Muddy water can be separated efficiently.

  Further, the separation of the sludge S is promoted by the smooth surface portion 9 of the separation cylinder 7. That is, by using the smooth surface portion 9, the inclination angle a of the smooth surface portion 9 with respect to the horizontal plane can be made a sharper angle and the separation distance can be increased as compared with the case where the smooth surface portion is not smooth. Separation is increased by the separation distance. In other words, the water on the sand and pebbles can be taken away and recovered accordingly.

  In addition, when the centrifugal separator 1 is applied to the excavation site, if the muddy water to be separated is muddy water derived from a stable liquid containing bentonite collected from the inside of the excavation hole, the rotation speed of the motor M or the like for the stable liquid separation is set. By setting, it is separated and recovered as a stable liquid for excavation (separation liquid) containing bentonite, so that it can be re-introduced into the excavation hole and used as it is at the site.

  On the other hand, since the sludge S is continuously discharged from the sludge discharge pipe 11, it is not necessary to remove the cake (lumps) of the sludge S accumulated on the inner wall surface of the separation cylinder 7 by centrifugal separation as in the prior art. Also good.

  Therefore, at the excavation site, the centrifuge 1 can be operated continuously, and the stable liquid circulation cycle (excavation hole (muddy water) → suction pump (muddy water) → centrifuge (clear water + bentonite, sludge S) → A supply pump (clarified water + bentonite) → drilling hole (muddy water)) is formed, and a single centrifuge 1 can cope with continuous excavation. As a result, capital investment costs and construction costs are reduced.

  As described above, the centrifugal separator 1 according to the present invention has been described according to the embodiment, but the present invention is not limited to the above.

  For example, by providing the separation cylinder 7 so as to be attachable / detachable, the rotation speed of the motor M can be adjusted by replacing the separation cylinder 7 with another separation cylinder 7 having an inverted conical inclination angle which is the bottom of the jacket portion 8 of the separation cylinder 7. Centrifugation of various types of fluids that cannot be separated by itself can be performed.

  Moreover, you may achieve the smooth surface of the smooth surface part 9 by metal mirror-finishing.

  Further, since the jacket portion 8 of the separation cylinder 7 is open at both ends and has a substantially cylindrical body portion and an inverted conical bottom portion, at least sand, pebbles, etc. that are difficult to adhere to the inner wall surface of the separation cylinder 7. If it is muddy water containing the separation object, continuous discharge is possible. On the other hand, in the case of a fluid to be treated including a separation target that is easily deposited, for example, clay, it may be difficult to continuously discharge by being deposited on the inner wall.

  In that case, for example, the entire inner wall surface of the separation cylinder 7, that is, the entire inner wall surface of the jacket portion 8 is a smooth surface, and the clay can be separated from the opening at the lower end by centrifugation and continuously discharged. Good.

  As another example, the components to be separated cannot be removed by one separation cylinder 7 so that other processing is required, such as removing pebbles and sand in the first stage and removing soil components in the second stage. In this case, different separation cylinders 7 may be serially processed in two stages.

  Furthermore, as another example, the smooth surface portion 9 may not be provided as long as the sludge S can be continuously discharged during centrifugation. In this case, as in the case of the smooth surface portion 9, the inclination angle a of the bottom portion of the inverted conical shape of the separation cylinder 7 and the rotational speed of the motor M described above are such that the gravitational force (slip-down force) related to pebbles and sand is sand. And the rotational speed and the inclination angle a (angle with respect to the horizontal plane) higher than the component force (running force) generated by the centrifugal force of the pebbles.

DESCRIPTION OF SYMBOLS 1 Centrifugal separator 2 Cylindrical case part 2a Separation liquid discharge port 2b Blind flange part 2A Large diameter cylinder part 2B Small diameter cylinder part 3 Upper cover 3a Nozzle insertion hole 4 Housing | casing 5A, 5B Bearing bearing part (outer ring)
6 Inflow nozzle (inflow means)
6a Tip portion 7 Separation cylinder 8 Jacket portion 8b Flange portion 9 Smooth surface portion 9a Smooth surface (separation surface)
10 Drive shaft portion 10a to 10c Bearing bearing portion (inner ring)
10d Pulley 11 Sludge discharge pipe 11a Fixed part 11b Discharge pipe part 11c Sludge receiving part M Motor (rotation drive means)
12 Endless belt (rotary drive means)
S sludge

Claims (7)

In a centrifuge for centrifuging a fluid to be treated containing sludge,
A separation cylinder having an opening at both upper and lower end portions provided rotatably and having a substantially cylindrical barrel portion and an inverted conical shape portion continuously formed at a lower portion of the barrel portion;
Rotation driving means for rotating the separation cylinder;
An inflow means that extends through an opening at an upper end of the separation cylinder and discharges the fluid to be treated toward the inner wall surface of the separation cylinder,
By the centrifugal rotation of the separation cylinder by the rotation driving means, the fluid to be treated discharged toward the inner wall surface is separated into a separation liquid and a sludge, and the separation liquid flows along the inner wall surface of the separation cylinder. The centrifuge characterized in that it rises and is discharged from the opening at the upper end, and the separated sludge is lowered and discharged from the opening at the lower end of the separation cylinder.   The centrifuge according to claim 1, wherein the inverted conical portion has a smooth surface portion.   The centrifuge according to claim 1 or 2, wherein the inflow means discharges the fluid to be processed in a direction following a rotation direction of centrifugal separation of the separation cylinder.   4. The centrifugal separator according to claim 1, wherein at least a part of an inner peripheral wall of the separation cylinder is formed of ethylene tetrafluoride.   The centrifuge according to any one of claims 1 to 4, wherein the fluid to be treated includes bentonite, and the bentonite is collected in the separated liquid by the separation.   The centrifuge according to any one of claims 1 to 5, wherein the separation cylinder is provided so as to be removable.   The centrifuge according to any one of claims 1 to 6, wherein the rotation driving unit includes a control unit capable of adjusting a rotation speed of the separation cylinder.

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