JPH0240248A - Centrifugal separator - Google Patents

Abstract

PURPOSE:To increase separation capacity and to prevent deterioration of capacity due to generation of a vortex by fitting a plurality of separation plates which are tilted for the lines radiated from a shaft center in a cylinder and provided in the radial directions while keeping the intervals in the lengthwise direction of the title separator to a supprting body fixed to a screw shaft. CONSTITUTION:Centrifugal force acts on liquid to be treated in the annular space and particles are relatively pushed to the radial directions. At this time, some particles are shortly allowed to collide against the surfaces of the correspondent separation plates 50 and thereafter flow down to the edge sides along inclination and flow out because the separation plates 50 are tilted for the radial lines. Further the edge sides of the separation plates 50 are separated from the plates 50 and the partition plates 41 in the circumferential direction because of the circumferential thickness of a supporting member and therefore the particles are passed through the separated parts and pushed to the inner surface of a cylinder 10. By such a way, the particles which have been separated from liquid and deposited near the inner surface of the cylinder 10 are continuously discharged as heavy phase substance W1 through an outlet 12a by the screw blades 22. On the other hand, clarified liquid separated from the particles is discharged as light phase substance W2 over a weir 13 while holding the liquid level L.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a horizontal screw centrifuge, and the present invention relates to a horizontal screw centrifugal separator. It is used to separate suspensions of organic substances such as polyethylene, and is particularly effective in separating sludge from water and sewage.

[Conventional technology]

In this type of horizontal screw centrifuge, as shown in FIG. 1, a cylindrical body 10 and a screw conveyor 20 arranged concentrically inside the cylindrical body 10 are rotated at different speeds by a rotary drive motor (not shown). The liquid to be treated W0 is supplied through the supply pipe 31 facing into the screw shaft 21, and is supplied from the through hole 21a to the screw shaft 2.
1 and the annular space between the cylindrical body 10 and push the particles to the inner surface of the cylindrical body 10 by the solid-liquid separation effect of centrifugal force.
These particles are scraped toward one end of the centrifugal separator by the screw blades 22 and discharged from the outlet 12a in the middle of the conical part 12 as heavy phase substances 'ff w + . , weir 1 at the end of the cylindrical part 1)
3, the method is to discharge it as light phase material W2.

On the other hand, disk-type centrifuges are known in which a large number of disks (separation plates) are stacked to increase the sedimentation area under the separation plates several tens to hundreds of times (compared to the sedimentation area of only a cylindrical body). Although it has excellent separation efficiency, since it does not have a solid matter discharge mechanism, it is difficult to discharge solid matter, and its uses tend to be limited.

In this respect, horizontal screw centrifuges forcefully discharge solid matter (particles) using the screw blades as described above, so solid matter can be discharged smoothly and a wide range of liquids can be separated. It can be used for.

However, for boat fishing, the horizontal screw conveyor does not have a separation plate, so the settling area is small and the separation efficiency is not sufficient.

Therefore, in order to improve separation efficiency,
No. 65 and No. 63-2218 disclose that a horizontal screw centrifuge is provided with a separation plate.

[Problem to be solved by the invention]

Although the techniques described in each of the above-mentioned publications have a high separation efficiency, the technique disclosed in Japanese Patent Publication No. 63-2218, which aims at particularly high separation efficiency, has various drawbacks as described below.

In other words, in order to ensure that each particle collides with the separation plate and has sufficient residence time when subjected to the action of centrifugal force,
As shown in Fig. 10, it is necessary to take a sufficient slope of the separator plate P and arrange a large number of separator plates P at small intervals, and because the length of the separator plate is long, the sludge stays for a long time. Particles tend to become deposits and adhere between the separation plates P and P, and it is not easy to clean the deposits.

In addition, if the protruding length of the separation plate P is long, the stress in the centrifugal force field is large, and in order to withstand this, the thickness of the plate must be increased or only the base is fixed, so that the centrifugal force causes the stress in the radial (arrow In order to prevent the separation IIyiP from being opened in
In practice, this poses major design difficulties, such as the need for a member to hold the tip.

Therefore, the main object of the present invention is to achieve high separation efficiency and to
To provide a centrifugal separator which can reduce the adhesion rate of particles by taking a large jli interval, can increase the separation capacity by sufficiently increasing the settling area of the particles, and does not reduce the separation capacity due to the generation of vortices. There is a particular thing.

[Means to solve the problem]

The problem described above is that the cylindrical body and the screw conveyor arranged concentrically inside the cylindrical body rotate at different speeds, and the liquid to be treated that is supplied to the annular space between the cylindrical body and the shaft of the screw conveyor is caused by centrifugal force. In a centrifugal separator that separates heavy-phase material and light-phase material and discharges them to the outside; separator plates are spaced apart in the radial direction within the annular space and are inclined to the radiation from the axis; This problem can be solved by providing a plurality of separation plates along the direction and fixing each separation plate to a support body fixed to the shaft of the screw conveyor.

In addition, if a plurality of partition walls are provided circumferentially protruding from the outer periphery of the screw conveyor shaft along the radial direction, and a group of separation plates is provided in each of the adjacent partition walls, each block between the partition walls can be Separation is possible while preventing interference with blocks, and the overall separation ability is increased.

[For production]

In the present invention, since a separation plate is provided, the sedimentation area increases, thereby improving the separation ability.

Further, a plurality of separation plates are provided in the radial direction. Therefore, in the radial direction, as in the prior publication, the sedimentation area increases and the separation ability improves, compared to the case where there is no substantial stacking.

Furthermore, in the present invention, the separation plates are not provided protruding from the screw shaft but are fixed to a support fixed to the screw shaft, so that a plurality of separation plates can be installed at intervals in the radial direction. This makes it possible to not only achieve the above-mentioned effects, but also to allow the separation plate to stand on a cantilever and support it on both sides, making it possible to support thin separation plates as well. The upper degree of freedom increases.

〔Example〕

The present invention will be explained below with reference to Examples.

1 to 4 show a first embodiment. In this embodiment, radial directions are placed on the outer periphery of the two screw shaft parts.
Eight partition plates 41, 41, . . . are provided protrudingly, for example, by welding, at equal intervals in the circumferential direction, and each partition plate 41, 41 forms one separated block, making up a total of eight blocks.

One separation block has a chevron-shaped separation plate 50°50...
A plurality of sheets are arranged at intervals in the radial direction, and in the illustrated example, there are ten sheets in total. These separation plates 50 are supported by three support members 42A, 42 that are integrated and protrude from the screw shaft 21 in the radial direction at intervals along the longitudinal direction.
A, 42A and the adjacent support member 4 spaced apart in the circumferential direction
2B, 42B.

42B, three separation plates 50. It is supported by fixing the side edges to 43.

On the other hand, the remaining five separation plates 50. have the same structure.
50...Group is supported. The support members in this case are designated by 42G and 42D, and the support members 42B and 42C are placed back to back, and the support member 42
A and 42D are in contact with the surfaces of the partition plates 41 and 41.

As shown in FIG. 1, the separation plate group consisting of a set of five separation plates 50 in such a supported manner is a plurality of separation plate zone groups Z+ and Zz in the illustrated example, which are two in the longitudinal direction. , as a whole centrifuge plate: 8 (separation block) XIO (inside separation block) x 2 (zone Z+, Zz)
=160 separation plates are arranged.

In the above centrifugal separator, the following operations are performed. That is, in a state where the cylindrical body 10 and the screw conveyor 20 are rotating at a different speed, the liquid to be treated W0 that is continuously supplied through the supply pipe 31 is transferred from the through hole 21a to the screw shaft portion 21 and the cylindrical body. It is guided into the annular space between the IO and the IO. In this annular space, centrifugal force acts on the liquid to be treated, and the particles are relatively pushed in the radial direction. At this time, after a certain particle collides with the surface of the corresponding separation plate 50, because the separation plate 50 is inclined to the radiation,
It flows down to the side edge along the slope of the separation plate 50 and flows out. The side edge of the separation plate 50 is spaced apart from the adjacent separation plate 50 and the partition plate 41 in the circumferential direction due to the circumferential thickness of the support member, so as shown in FIGS. 3 and 4, It is pushed to the inner surface of the cylindrical body 10 through these spaced parts. In this way, the particles separated from the liquid and accumulated near the inner surface of the cylindrical body 10 are scraped by the screw blades t122 toward the conical portion 22 and further toward the outlet 12a.
It is continuously discharged from a as a heavy phase substance W.

The clarified liquid from which particles have been removed is discharged from the weir 13 as light phase material W2 while maintaining the liquid level.

In the above example, the intervals between the groups of separation plates 50, 50, etc. are equal and the length of the separation plates is short, thereby preventing deposits from adhering to the separation plates.

The angle θ between the separation plate 50 and the radiation is preferably 40 to 70 degrees, particularly 45 to 60 degrees. Also, there is a separation plate 50.50
...The number of groups may be a plurality of sheets, but is more preferably three or more. Although the separation plate 50 is a flat plate in the above example, it may be a curved plate 50A as shown in FIG. 5 or a bent plate 50B as shown in FIG. Although it is desirable that the intervals between the separating plates 50 and 50 be equal, even if there is some inconsistency, the practical hindrance may be ignored compared to the effect of increasing processing capacity.

In the first embodiment, two separation plate groups were provided between the partition plates 41 and 41, but as shown in FIG. 7, there may be one separation plate group. The set of the separation plate group and the support body can be detachably attached to the screw shaft part using a cassette system. A plurality of partition plates 41 is sufficient, but preferably three or more. A partition plate 41 is provided,
Although the reason is unclear, when the processing area is divided in the circumferential direction,
Separation performance is improved compared to the case where the partition plate 41 is not provided.

On the other hand, if the separation plate group is divided along the longitudinal direction of the centrifuge as shown in FIG. 1, the separation performance will be improved compared to the case where it is not divided. The reason for this is not certain, but it is thought that this is because zone Z on the right side of Figure 1 performs rough separation and zone Z2 performs purification separation.The number of 0 divisions is 3 or more. There may be.

FIG. 8 shows yet another example. In this example, a support member 42B is used in common, and a separation plate 50' is fixed to this support member 42E and the partition plate 41. As in this example, the "support body" referred to in the present invention includes the support member 4
In addition to 2A to 42E and the arc plate 43, the partition plate 41 may also be included. Although FIG. 9 is a combination of the example shown in FIG. 3 and the example shown in FIG. 8, no further explanation is necessary.

〔Example〕

Next, the effects of the present invention will be explained using examples.

(Example 1) The body diameter of the cylindrical body is 24 inches x the total length of the separator is 72 inches,
For a centrifugal separator with a conical part having an elevation angle of 18 degrees, a chevron-shaped separation plate group as shown in Figure 3, which is made by stacking three separation plates with an axial length of 800 mm, is set to 8 In this case, as shown in Fig. 3, there are no separating plates fixed to the arc plate, and each separating plate is a support member. It stuck to. The spacing between the separation plates was 20u+.

The operation was carried out at a rotational speed of the cylindrical body of 2200 rpm, and excess activated sludge with a feed concentration of 0.4% by weight was used as the liquid to be treated.

(Example 2) The same as Example 1 except that the interval between the separation plates was set to 15 fins.

(Comparative example) It was the same except that it did not have a separation plate.

(Results) When we investigated the recovery rate by changing the supply flow rate in three stages, we found that
The results shown in the table were obtained.

Table 1 Note) The percentage value indicates the recovery rate.

Thus, it can be seen that by providing the separator plate, the throughput is significantly improved according to the present invention under the same power consumption. It can also be seen that the processing capacity can be increased by reducing the interval.

〔Effect of the invention〕

As described above, the present invention provides advantages such as a significant increase in processing capacity.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the centrifuge of the present invention, Fig. 2 is a cross-sectional view thereof, Fig. 3 is an enlarged view of its main parts, Fig. 4 is a perspective view of a group of separating plates, Figs. 6 is a perspective view of a separating plate having a different shape, FIGS. 8 and 9 are sectional views of other examples of supporting the separating plate, and FIG. 1θ is a sectional view of a conventional example. W,...Liquid to be treated, W,...Heavy phase substance, Wt...
Light phase substance, 10... Cylindrical body, 12... Outlet, 13.
... Weir, 21 ... Screw shaft portion, 22 ... Screw blade, 41 ... Partition plate, 42A to 42E ... Support member, 43 ... Arc plate, 50.50A, 50B, 50
'... Separation plate. Figure Figure Figure Figure Figure Figure Figure Procedure Amendment Written Type) % Formula % Display of the Case 1987 Patent Application No. 187894 2, Title of Invention Centrifugal Separator 3° Amendment Case Related address name

Claims (2)

[Claims] (1) The cylindrical body and the screw conveyor arranged concentrically inside the cylindrical body rotate at different speeds, and the liquid to be treated that is supplied to the annular space between the cylindrical body and the shaft of the screw conveyor is weighed by centrifugal force. In a centrifugal separator that separates a phase substance and a light phase substance and discharges them to the outside; Separation plates are arranged in the annular space at intervals in the radial direction so as to be inclined to the radiation from the axis, and in the longitudinal direction of the machine. A centrifugal separator characterized in that a plurality of separation plates are provided along the axis of the centrifugal separator, and each separation plate is fixed to a support body fixed to a screw conveyor shaft. (2) The centrifugal separator according to claim 1, wherein a plurality of partition walls are provided circumferentially protruding from the outer periphery of the shaft portion of the screw conveyor along a radial direction, and a group of separation plates is provided in each adjacent partition wall.