JP3402418B2 - Centrifugal concentrator - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a screw decanter type centrifugal concentrator used for solid-liquid separation of a suspension containing a fine solid substance in a liquid.

[0002]

2. Description of the Related Art In a decanter type centrifugal concentrator of this type, a screw conveyor is coaxially arranged in a rotating bowl rotating at a high speed so that the rotating bowl and the screw conveyor rotate in the same direction with a speed difference. The liquid to be treated introduced into the rotating bowl through the supply pipe contains a large amount of clarified separated liquid and fine solids due to the action of centrifugal force to settle the particles on the inner peripheral wall of the rotating bowl. And concentrated solution. The concentrated liquid is discharged from the concentrated liquid discharge passage while being scraped to one side of the rotating bowl by the screw blades of the screw conveyor, and the separated liquid is discharged to the outside from the separated liquid discharge passage formed on the other side of the barrel. have.

Various discharge mechanisms for the concentrated liquid and the separated liquid (both of which are also referred to as discharge liquids hereinafter) have been developed in the past, such as that disclosed in Japanese Patent Publication No. 63-31261.

According to the present invention, in the prior art, since the discharged liquid needs to be discharged through the discharge passage formed in the outer peripheral portion of the rotary bowl, the discharged liquid is discharged at a large peripheral speed, so that a large amount of power is required. It solves the need to rotate.

As a specific structure for this purpose, a plurality of skimmer tubes are radially fixed to the end surface of the body of the screw conveyor, and the open ends of the skimmer tubes are extended to the vicinity of the inner wall of the rotating bowl. The concentrated liquid thus collected is guided through a skimmer tube into a hollow support shaft of a rotating bowl. Further, for the separated liquid, a plurality of linear guide channels in the radial direction are formed in the body of the screw conveyor, each guide channel is opened to the outer surface of the body, and each guide channel is a hollow of the screw conveyor. Connect it to the inside of the support shaft to discharge the separated liquid to the outside of the machine through the hollow support shaft, and to discharge the concentrated liquid to the outside of the machine through the gap between the support shaft of the screw conveyor and the support shaft of the rotating bowl. It is the one. Further, flow rate control valves for adjusting the discharge amounts of the concentrated liquid and the separated liquid are respectively provided.

[0006] In addition, as a device in which a concentrated liquid or the like is discharged from the shaft center portion in order to reduce power consumption, Japanese Patent Laid-Open No. 62-45363 and Japanese Utility Model Laid-Open No. 62-13623 are known.
No. 7, gazette No. 2-86652, gazette No. 2-8
Some are disclosed in Japanese Patent No. 6653.

[0007]

[Problems to be Solved by the Invention]
The structure described in JP-A-31261 which discharges the discharged liquid through the support shaft portion has an advantage of low power consumption, but the skimmer pipe and the guide passage extending in the radial direction have a cross section along the radial direction. All of them are the same and narrow, so that the inner wall surface of the skimmer tube in which the concentrated liquid containing a large amount of fine solid matter flows is particularly abraded and easily clogged. Further, since the concentrated liquid stays between the skimmer pipes and the inflow portion of the skimmer pipe is narrow, a dead space is likely to occur, and the separation concentration of the discharged concentrated liquid changes with time. There's a problem.

Further, in the case of miniaturization, reducing the diameter of the skimmer tube reveals the above-mentioned problems, so that it cannot be applied to a small centrifugal concentrator in practice. .

Moreover, since the liquid to be treated is supplied from one side of the device and the concentrated liquid and the separated liquid are discharged on the other side of the device, respectively, it is a parallel flow type, so that the structure can discharge the concentrated liquid. There is a risk that the inlet port for separation and the inlet part for discharging the separated liquid cannot be clearly distinguished as the liquid flow, and the particles of the concentrated liquid are often mixed in from the outlet for discharging the separated liquid.
It is greatly affected by operating conditions and its processing capacity is limited.

[0010] Therefore, the applicant of the present invention has previously disclosed that the concentrated liquid and the separated liquid are clearly distinguished and smoothly discharged, and the main purpose is to reduce the power consumption required for operation. In the publication, while the conventional examples for the purpose of energy recovery were parallel flow type, an example of counter flow type was proposed. As a result, it was also proved that the separation characteristics of the concentrated liquid and the separated liquid were actually improved as compared with the conventional example.

However, thereafter, depending on the type of the liquid to be treated, the concentrated liquid collected on the discharge side of the concentrated liquid is likely to accumulate between the screw blade and the weir, and may stay without going through the weir. It was found that there is a possibility that it may hinder stable driving for a long time.

Therefore, the main object of the present invention is to provide a countercurrent type centrifugal concentrator, in which the weir is made to smoothly dive in discharging the concentrate so that the concentrate stays and deposits between the screw blade and the weir. It is to prevent and increase the concentration of the concentrated liquid to ensure stable discharge.

[0013]

In the centrifugal concentrator of the present invention which has solved the above-mentioned problems, a screw conveyor is concentrically arranged in a horizontally supported rotating bowl, and the rotating bowl and the screw conveyor are in the same direction. At a high speed with a differential speed, the liquid to be treated supplied from the outside to the longitudinal intermediate position of the pool space formed between the rotating bowl and the screw conveyor is separated into a concentrated liquid and a separated liquid by centrifugal force. While the concentrated liquid is collected on one side of the rotating bowl and the separated liquid is collected on the other side of the rotary bowl, and these are discharged to the outside from an independent discharge path, the screw conveyor is a screw conveyor main body and screw blades. has the door, a weir is provided to protrude in the bowl inner surface side of the outer peripheral surface at the concentrate exhaust side end portion of the screw conveyor body, to face the weir In an annular space between the end of the bowl, at intervals in the circumferential direction, a plurality of concentrate exhaust vanes fixed to the end of the weir or the bowl, the space of the annular, the pool space And a cone portion whose radius increases toward the concentrate discharge side between the outer peripheral surface of the screw conveyor body and the vicinity of the outer peripheral edge of the weir , which are respectively communicated with the concentrate discharge path in the hollow shaft of the screw conveyor. Provided, the screw blade of the portion corresponding to this cone,
It is characterized in that it is provided so as to surround the outer peripheral surface of the cone portion.

In this case, the screw blade may have a double blade structure at least in the portion corresponding to the cone portion.

In the present invention, since the cone portion whose radius increases toward the concentrated liquid discharge side is provided between the outer peripheral surface of the screw conveyor main body and the vicinity of the outer peripheral edge of the weir , the rotation of the screw conveyor causes concentration. Assures low-concentration liquid on the screw conveyor body side along the cone.
Since it can be guided near the outer edge of the weir ,
The concentrated liquid can be smoothly drained through the weir without accumulating between the weir and the weir . Moreover, it is possible to enhance the concentration effect while consolidating in the process of transferring the low-concentration liquid to the weir along the cone portion.

In the conventional parallel flow system, even if a cone portion is provided to enhance the concentration effect, the installation of the cone portion makes it impossible to discharge the separated liquid. Therefore, the configuration of providing the cone portion according to the present invention is meaningful in combination with the adoption of the countercurrent system.

[0017]

[Description of structure]

1. Overall configuration of centrifugal concentrator (see mainly FIG. 1) A cylindrical (rotating) bowl having an appropriate size for receiving a continuous supply of a suspension as a liquid to be treated and concentrating the suspension by centrifugal force. 10 is a flange portion 11a of the hollow shaft 11 and a flange portion 12a of the hollow shaft 12 at both ends thereof.
And is rotatably supported via both shafts 11 and 12. Flange portion 11a and flange portion 12
Each a constitutes an end portion of the bowl 10.

The screw conveyor 20 has end plates 2 at both ends.
The end plate 21 is composed of a screw conveyor body 21 having 1A and 21B and a screw blade 22.
Hollow shafts 23 and 25 are fixed to A and 21B.

The screw blade 22 is fixed to the screw conveyor main body 21 with a slight gap such that the outer edge of the screw blade 22 contacts the inner peripheral surface of the bowl 10. The left end of the screw blade 22 is supported on an outer end 42a of a horizontally extending support plate 42 fixed on the outer peripheral surface of the screw conveyor main body 21 and reaches the vicinity of the flange 11a.

A screw conveyor 20 is provided in the bowl 10.
However, hollow shafts 23 and 25 are rotatably and concentrically arranged in the hollow shafts 11 and 12, respectively. Bowl 10 has a cover 70
It is located inside.

The bowl 10 and the screw conveyor 20 are rotated by the differential device 30 through the hollow shafts 11 and 23, respectively, in the same direction with a speed difference.

A hollow shaft 24 is concentrically arranged and fixed in the hollow shaft 23, and a coaxial supply passage 24a is connected to a guide passage 31. The guide path 31 opens at the central position of the bowl 10.

2. Configuration on Discharged Separated Liquid Side (See FIGS. 1, 2, and 4) On the outer peripheral surface of the left end portion of the screw conveyor main body 21, a plurality of (for example, 4 to 12) the support plates 42 are erected radially at equal intervals. It is fixed.

The outer edge 42a of the support plate is attached to the screw blade 22.
Up to, for example, about 1/3 of the height of the
c respectively protrude to substantially the same position as the side edge 40c of the discharge vane described later, and the rear end 42b of the support plate extends from the front end 42c toward the center of the bowl 10 by a length of about one pitch of the screw blades 22. There is.

The flange portion 2 of the hollow shaft 23 integrated with the left end plate 21A of the screw conveyor body 21.
3b includes a plurality of sheets (for example, 2 to 6) at equal intervals in the circumferential direction.
The discharge vanes 40 of one sheet are arranged and fixed radially at a position different from the support plate 42.

The inner end 40b of the discharge vane 40 and the hollow shaft 23
A gap is provided between the outer peripheral surface of the screw conveyor main body 21 and the side edge 40c and the flange portion 11a of the hollow shaft 11, and the outer end 40a slightly projects from the outer peripheral surface of the screw conveyor main body 21.

The flow path of the separated liquid is a plurality of open spaces in the horizontal direction formed by a plurality of support plates 42 standing up in the radial direction on the same surface as the outer peripheral surface of the screw conveyor main body 21 and extending to the left end side, An annular space formed by the screw blades 22 rotating with the screw conveyor 20 and the flange portion 11a rotating with the bowl 10 and deformed due to a difference in rotation speed, a surface of the flange portion 23b of the hollow shaft 23, and a radial surface on the same surface. An annular space that is divided into a trapezoidal shape by a plurality of discharge vanes 40 that are set up at equal intervals, and the flange portion 11a side is open;
It is constituted by a side edge 40c of the discharge vane rotating with the screw conveyor 20 and an annular space between the annular space and the flange portion 11a rotating with a speed difference, and the discharge passage 23a of the hollow shaft 23 is provided in these spaces. Is open.

3. Condensate discharge side configuration (see FIGS. 1, 3 and 5) At the right end of the screw conveyor main body 21, the end plate 21B is provided.
An annular weir 26 is fixed to the surface of the member 26, and a plurality of pieces (for example, 4 or 6 pieces) are equally spaced on the surface of the member 26 in the circumferential direction.
The curved concentrated liquid discharge vane 41, whose outer end 41a precedes the inner end 41b, is arranged and fixed.

The inner end 41b of the discharge vane 41 and the outer peripheral surface of the hollow shaft 25, the outer end 41a and the inner peripheral surface of the bowl 10, and the side edge 41c and the flange portion 12a of the hollow shaft 12 each have a gap. is doing.

The concentrated liquid discharge vane 41 may be fixed to the weir 26 or the end plate 21B, or may be fixed to the flange portion 12a forming the end portion of the bowl instead of these modes.

The flow path of the concentrated liquid is divided into a deformed trapezoidal shape by the surface of the weir 26 and the curved discharge vanes 41 standing at equal intervals on the same surface, and the annular portion whose flange portion 12a side is open. A space and an annular space between the side edge 41c of the discharge vane rotating with the screw conveyor 20 and the flange portion 12a rotating at a differential speed, and the discharge path 25 of the hollow shaft 25 is formed in these spaces.
a is open.

4. Furthermore, the discharge passage 23 for the separated liquid and the concentrated liquid
The adjustment valve 5 is provided only in the concentrated liquid discharge passage 25a of a and 25a.
0 is provided (see FIG. 1).

[Explanation of Operation (Flow of Liquid)] Flow of Suspension The suspension to be processed is continuously supplied to the central position in the bowl 10 via the supply passage 24a of the hollow shaft 24 and the guide passage 31.

The suspension supplied to the central position of the bowl 10 is separated into a separated liquid and a concentrated liquid by centrifugal force, and the separated liquid is the outer peripheral surface of the screw conveyor main body 21, the screw blades 22 and 22, and the bowl. 10 passes through the inside of the pool space formed by the inner peripheral surface of the bowl 10 to the left end side of the bowl 10, and the concentrated liquid flows to the right end side of the bowl 10 opposite to the separated liquid, and the screw blade 22 having the differential speed with the bowl 10 Are collected by the discharge passages 23a through the following flow forms,
It is discharged from 25a.

2. Most of the separated liquid that has flowed to the left end side of the bowl 10 flows horizontally through the plurality of open spaces, and while swirling, it flows through the annular space of the same section. The separated liquid merges with the open space formed on the tip side of the support plate 42, and thereafter, while exhibiting a complicated flow including liquid movement and swirling, the discharge passage 23a of the hollow shaft 23.
Be led to.

3. Concentrated liquid flow The concentrated liquid collected on the right end side of the bowl 10 by the screw blades 22 passes through the entire circumference of the outer end of the dip wear 26 to form an annular open space divided into the plurality of deformed trapezoids. The discharge path 25 of the hollow shaft 25 is sent while exhibiting a complicated flow including liquid movement and swirling between the two.
is led to a.

[Cone Part] In the present invention, as shown in FIGS. 1, 3 and 6 as a representative (FIG. 6 is a view developed with reference to the outer peripheral surface of the screw blade), In particular, the cone portion 6 whose radius increases toward the concentrated liquid discharge side between the outer peripheral surface of the screw conveyor main body 21 and the vicinity of the outer peripheral edge of the weir 26.
0, and the screw blade 22 (22A) corresponding to the cone portion 60 is provided so as to surround the outer peripheral surface of the cone portion 60.

In the illustrated example, since the end plate 21B projects from the outer peripheral surface of the screw conveyor main body 21, the cone portion 60 is fixed to the outer peripheral portion of the end plate 21B by welding or the like.

The extent of expansion of the cone portion 60 is preferably lower than the outer peripheral edge of the weir 26 as in the illustrated example, but can be appropriately selected up to the same height.

On the other hand, in the illustrated example, FIGS.
As shown in, the screw blade 22A is fixed to the screw blades 22 that are continuously continuous over the entire length, and the screw blades 22A are fixed between the screw blades 22 from the middle, and the screw blades 22 are screwed for one pitch. It is a screw blade having a double blade structure provided at the same pitch as the blade 22.

The ends of the screw blades 22 and 22A shown in FIGS. 5 and 6 are 1
They are positioned at 80 degrees apart.

If the cone portion 60 does not exist, the concentrated liquid conveyed near the outer peripheral surface of the screw conveyor main body 21 becomes
It is necessary to move the radial distance to the outer edge of the weir 26. For this reason, the cone portion 60 is provided, whereas the area Z in FIG.
As shown in FIG. 3, the particles can be sequentially fried (moved) along the cone portion 60, and the drainage vanes of the concentrated liquid can be dipped under the outer peripheral edge of the weir 26 without causing retention. It can be led between 41 and 41.

In this case, as shown in the drawing, by using a screw blade having a double-blade structure, the main concentrated liquid overflows at two locations instead of one, so that it is almost even in the circumferential direction. The concentrated liquid can be stably discharged while the concentrated liquid is made to pass through the weir .

When it is difficult to consolidate the suspension of interest, the cone portion is expanded from the vicinity of the guide passage 31 of the screw conveyor main body 21 in order to make the cone portion longer than in the illustrated example and enhance the consolidation effect. be able to.

[0045]

As described above, according to the present invention, since the discharged liquid is collected at the shaft center and discharged from the support shaft portion, a small rotational driving force is sufficient, and further, a conventional drain pipe such as a skimmer pipe is used. The problem of uneven wear of the inner wall of the pipe, clogging, and discharge, which occurred when using, was solved all at once, and stable operation can be performed.In particular, in a countercurrent centrifugal concentrator, Advantageously, the weir can be smoothly dipped to prevent retention and deposition of particles between the weir and the screw blade, and stable discharge of the concentrated liquid can be performed. Moreover, by providing the cone portion, the consolidation effect can be enhanced and the concentration characteristic can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the overall structure of a centrifugal concentrator according to the present invention.

FIG. 2 is an enlarged view of a portion X in FIG.

FIG. 3 is an enlarged sectional view of a Y portion of FIG.

FIG. 4 is a view taken along line 4-4 of FIG.

5 is a view taken along line 5-5 of FIG.

FIG. 6 is a development view for explaining a screw conveyor.

[Explanation of symbols]

10 ... Bowl, 11, 12 ... Hollow shaft, 20 ... Screw conveyor, 21 ... Screw conveyor main body, 22, 22
A ... Screw blade, 23, 24, 25 ... Hollow shaft, 26
... weir , 30 ... differential device, 31 ... guideway, 40 ... separated liquid discharge vane, 41 ... concentrated liquid discharge vane, 42 ... support plate, 5
0 ... Regulator valve, 60 ... Cone part, 70 ... Cover.

Continuation of front page (56) Reference JP-A-57-56061 (JP, A) JP-A-60-64657 (JP, A) JP-A-53-117859 (JP, A) JP-A-58-43252 (JP , A) JP 59-136152 (JP, A) JP 62-45363 (JP, A) JP 7-859 (JP, A) Actual development 57-9346 (JP, U) Actual development 62-13551 (JP, U) Actual opening 61-204657 (JP, U) Actual opening Sho 62-136237 (JP, U) Actual application Sho 63-168099 (Actual opening 2-86652) Microfilm filming the contents of the detailed description and drawings (JP, U) Microfilm filming the contents of the detailed description and drawings attached to the application for Japanese Patent Application No. 63-168100 (Japanese Utility Model Publication No. 2-86653) ( (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B04B 1/20

Claims (2)

(57) [Claims] 1. A screw conveyor is concentrically arranged in a horizontally supported rotating bowl, and the rotating bowl and the screw conveyor rotate at high speed in the same direction with a differential speed, and between the rotating bowl and the screw conveyor. While separating the liquid to be treated supplied from the outside at an intermediate position in the longitudinal direction of the pool space formed into a concentrated liquid and a separated liquid by centrifugal force, the concentrated liquid is placed on one side of the rotating bowl and the separated liquid is Collected on the other side, respectively, in a centrifugal concentrator that discharges these to the outside from an independent discharge path, the screw conveyor has a screw conveyor main body and a screw blade, at the concentrated liquid discharge side end of the screw conveyor main body protrudes from the outer peripheral surface in the bowl inner surface side weirs provided, location in the annular space, the intervals in the circumferential direction between the end of the bowl opposite to the weir Te, a plurality of concentrate exhaust vanes fixed to the end of the weir or the bowl, the space of the annular each in communication with the concentrate exhaust passage in the hollow shaft of the pool space and screw conveyor, the screw conveyor A cone portion whose radius increases toward the concentrated liquid discharge side is provided between the outer peripheral surface of the main body and the vicinity of the outer peripheral edge of the weir , and the screw blade corresponding to this cone portion is located on the outer peripheral surface of the cone portion. A centrifugal concentrator, which is characterized in that: 2. The centrifugal concentrator according to claim 1, wherein the screw blade has a double blade structure at least in a portion corresponding to the cone portion.