JPS6182855A - Screw-decanter type centrifugal separator - Google Patents

Abstract

PURPOSE:To obtain a clean separated soln. and a dehydrated cake small in water content by installing a multichamber for a feed chamber provided to an internal cylinder and moving a feed pipe to a longitudinal direction so that the material to be treated is introduced into an optional chamber. CONSTITUTION:In a screw-decanter type centrifugal separator, the plural feed chambers 13 are juxtaposed in the axial core direction of the internal cylinder 1 on an internal cylinder 1l and communicated with an external chamber 4 via a discharge port 6 for raw liquid in every chamber 13 and a feed pipe 3 is freely adjusted to the position in the axial core direction so that the tip thereof is faced to an optional chamber. By this method, since the feed chambers can be selected if necessary, the high recovery rate of solid material and the low water content of cake are obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to sludge generated in water, sewage, and human waste treatment plants that require shunt dewatering, chemical plants, food manufacturing plants, etc. Screw decanter type centrifuges are widely used in the field of separating and dewatering solids from slurry liquids, such as valuables that need to be recovered from manufacturing processes and solids generated in industrial wastewater treatment plants that require separation and dehydration. The present invention relates to a centrifugal separator, and particularly relates to a screw decanter type centrifuge in which a plurality of supply chambers are provided inside the inner shell so that the material to be processed (undiluted solution) can be supplied to any one of the supply chambers.

[Prior art]

A conventional screw decanter type centrifugal separator, as shown in Fig. 1, has one feed chamber 2 in an inner shell 1, and a feed pipe 3 facing this feed chamber 2 is fixed in position. An outer shell 4 is rotatably provided on the outside of the inner shell 1 with a bearing 5, and when the material to be processed (undiluted solution) is fed into the supply chamber 2 through the feed pipe 3, the inner shell 1
The stock solution is supplied into the outer shell 4 through a stock solution discharge port 6 provided in the supply chamber 2, and the stock solution supplied to the outer IFI 4 undergoes a separation action when the outer shell 4 rotates at high speed. The solids in the stock solution immediately settle due to centrifugal force to form a solid layer 10, which is scraped out by the screw 7 and discharged from the outer shell 4 through the cake discharge port 8 provided in the outer shell 4. The separated retentate 11 forms a pool within the outer shell 4, overflows an orifice 9 provided in the outer shell 4, and is discharged to the outside of the outer shell 4. That's how it is.

12 is a support arm for the feed pipe.

However, in the conventional screw-de-canter type centrifugal separation machine described above, the stock solution is supplied to the supply chamber 2 through the feed pipe 3.
Since there is only one undiluted solution discharge port 6 for supplying the undiluted solution into the outer shell 4, there are 14 fixed positions. As a result, the following problems occurred.

■ In order to obtain a clear nitric solution, a so-called settling/separation zone is required between the stock solution discharge port of the inner shell 1 and the orifice 9 to complete the settling and separation. The longer the distance from to the orifice 9, the better.
In order to obtain a cake with a low content rate, it is better to allow the settled and separated solids to stay in the outer shell 4 as much as possible to lengthen the dehydration time, but since there is only one outlet 6 for the raw solution, , it is not possible to satisfy all of the above contradictory demands.

The above dewatering time can be lengthened by adjusting the scraping speed of the screw 7, but there is a limit.

■ For processed materials where sedimentation and separation occur immediately near the raw solution outlet 6, the sedimentation and separation zone from the raw solution outlet 6 to the orifice 9 is not used effectively, and the dehydrated cake with a high moisture content is It is being discharged.

[Purpose of the invention]

The performance required for a screw decanter centrifuge is:
A longer settling and separation zone is required to obtain a higher solids recovery (clear fraction #I liquid) and lower cake moisture content (dehydrated cake with low water content), and a more in-containing fraction M liquid. Also, to obtain a cake with a lower moisture content, a longer dewatering zone is required.

The present invention satisfies the performance required of the screw decanter type centrifuge by making it possible to arbitrarily change the sedimentation/separation zone and the dehydration zone in the same machine depending on the properties of the material to be treated and the purpose of treatment. The purpose is to

[Structure of the invention]

In order to achieve the above object, the screw decanter type centrifuge of the present invention has a configuration similar to that of a conventional centrifugal separator, has multiple supply chambers provided in the inner shell, and is supplied by a feed pipe. The feed pipe is movable in its longitudinal direction so that the material to be treated (undiluted solution) enters any supply chamber.

More specifically, as shown in FIG. 2, a large number of supply chambers 13 (in the drawing, one , Il
, I, and ■) are provided, and a feed pipe 15 for supplying the stock solution to the supply chamber 13 is supported movably in the axial direction thereof, and an extension of the tip of the feed pipe 15 is provided. A baffle plate 16 positioned on a line is attached to the tip of the feed pipe 15 via a support rod 17, so that the stock solution sent by the feed pipe 15 can be supplied from the tip of the feed pipe 15 to each supply chamber. The stock solution is fed into the outer shell 4 through the stock solution discharge port 6 provided in each supply chamber.

As shown in FIGS. 3 and 4, the shape of the tip of the feed pipe 15 is such that a support rod 17 is fixed to the tip of the feed pipe 15 by welding in the same axial direction, and A baffle plate 16 is attached to the tip of the rod 17 by welding in a perpendicular direction, and the stock solution is placed in one supply chamber (for example, one
room) when the adjacent supply room (e.g.
In order to prevent the stock solution from flowing into the chamber (1) with the baffle plate 16, the feed pipe 15 is installed as shown in FIG.
The length of the support +117 is determined so that the distance a from the tip of the support plate 16 to the baffle plate 16 is equal to the width of one supply chamber. In addition, the role of the L baffle plate 16 is to
This is to prevent the stock solution coming out from the tip of 5 from going straight due to the flow velocity and entering each supply chamber through the hole in the center of the partition wall of each supply chamber, but the baffle plate 16 must pass through each partition 14. Therefore, the clearance θ between the inner surface of the hole at the center of each partition wall 14 and the outer surface of the baffle plate 16 is set to about 1111. The reason why the number of support rods 17 is one is to prevent the outflow of the liquid from being obstructed.
If books are used side by side, there is a risk that sludge will get stuck and create a bridge. 'The feature of the structure of the present invention is the above point, but the other structure is the same as that shown in FIG.
Therefore, the same reference numerals are used for the same items.

The screw decanter centrifuge of the present invention includes the above +;
For example, when the clarity of the separated liquid is important, or when it is desired to reduce the content of the cake as much as possible, it can be easily realized as follows.

First, if the blue light property of the separated liquid is important, pull out the feed pipe 15 to the outside and connect the tip of the feed pipe 15 to the first pipe in the supply chamber 13 that is closest to the cake discharge port 8.
the room and bring it to the state shown in Figure 6. As a result, the sedimentation/separation zone from when the stock solution supplied to the first chamber of the supply chamber is supplied into the outer shell 4 through the stock solution discharge port 6 to the orifice 9 becomes the longest, resulting in a high solids recovery rate. A clear fraction M solution will be obtained.

Next, if you want the moisture content of the cake to be as low as possible,
As shown in FIG. 7, the feed pipe 15 is pushed into the inner shell 1, and its tip is set in the second chamber closest to the orifice 9 among the supply chambers 13. As a result, the dehydration zone from the stock solution discharge port 6 to the cake discharge port 8 in the first chamber becomes the longest, making it possible to increase the length of solid matter accumulation and obtain a lower cake moisture content.

It has also been found through experiments that the longer the length of the solid matter deposited, the lower the cake moisture content.

The experimental results show that the relationship between the deposition length and cake moisture content is as shown in Table 1, and as shown in FIG. 8, which is a graphical representation of Table 1.

The experimental results were obtained when the stock solution was supplied to the first chamber of the supply chambers 13, and were not obtained from the first chamber to the second chamber.

Table 1: Relationship between pile length and cake moisture content Notes
In the case of the first supply chamber, the orifice is also 1. Coagulant addition rate: maximum (jq) As can be seen from Table 1 and Fig. The water content is low. Therefore, it is desirable to use continuous rotation that increases the M [plying length] within a range that does not deteriorate the solids recovery rate.

In addition, in FJ materials where sedimentation and separation occur immediately, sedimentation and separation are completed near the first chamber of the supply chamber, and the solids accumulation length is distributed between the first chamber and the cake discharge port 8. For such treated materials, there is no need to make the sedimentation/9-layer zone long, so the tip of the feed pipe 15 is set in the chamber (①) so that the undiluted solution is supplied to the chamber (②), and the length of solid matter accumulation is If the retention time of the solids in the outer shell 4 is increased, the dehydration time becomes longer, and as can be understood from the data in FIG. 8, a high solids recovery rate and a lower cake moisture content can be obtained.

Note that the shape of the tip of the feed pipe 15 is such that instead of attaching the baffle plate 16 via the support rod 17, the tip of the feed pipe 15 is closed and a hole is opened at the tip to allow the stock solution to flow out in the right angle direction. You can also use it as Further, it is a matter of course that the stock solution is supplied to the 0th and ① chambers depending on the properties of the object to be treated and the purpose of treatment.

〔Effect of the invention〕

Since the screw decanter 5 centrifugal separating machine of the present invention has the construction and action as explained above, it can produce the following effects.

(i) With the same machine, operating conditions suitable for JR can be arbitrarily and easily selected depending on the properties of the object to be treated and the purpose of treatment. That is, the length of the sedimentation/separation zone and the length of the dehydration zone can be arbitrarily selected.

(i) Efficient operation is possible.

(g) In particular, a: lower cake moisture content can be obtained for the treated material that undergoes immediate precipitation and separation.

Even if the number of supply chambers increases, it can be adjusted by simply lengthening the Gψ feed pipe, and the configuration is simple and great effects can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional screw decanter type centrifugal machine, and Figure 2 is a sectional view of a screw decanter type centrifugal machine of the present invention.
41, FIG. 3 is a side view showing the feed pipe end A1ff1 in the centrifugal sorting machine of the present invention, and FIG.
Figure 5 is a plan view of Figure 5, which shows the mutual relationship when the tip of the feed pipe is positioned within the supply chamber, Figures 6 and 7.
The figure is a schematic diagram of the shelf showing the fifth condition of operation, and FIG. 8 is a diagram showing the relationship between the stacking length and the moisture content of the cake. 1 is an inner shell, 2 is a supply chamber, 3 is a feed pipe, 4 is an outer shell, 6 is a stock solution discharge port, 7 is a screw, 8 is a cake discharge port, 9 is an orifice, 1o is a solid matter accumulation layer, 11 is a separation 13 is a supply chamber, 14 is a partition wall, 15 is a feed pipe,
16 indicates a baffle plate.

Claims (1)

[Claims] 1) The material to be processed is supplied through the feed pipe to the supply chamber in the inner shell, and from the supply chamber is supplied into the outer shell through the raw solution outlet, and the liquid and solids are separated by high-speed rotation of the outer shell, and the solids are separated. In a screw decanter type centrifugal separator, the material is scraped out with a screw and the liquid is discharged as a cake to the outside of the outer shell, and the separated liquid is also discharged to the outside of the outer shell. They are arranged side by side, and each chamber is communicated with the inside of the outer shell through a stock solution discharge port, and the position of the feed pipe is freely adjustable in the axial direction so that its tip can face any chamber. Screw decanter type centrifuge.