JPS6130604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for separating precipitated solids and liquids in a water treatment apparatus and transporting only the solids out of the system.

Although there are various types of solid-liquid separators, mechanical methods are most often used in gravity-type solid-liquid separators to transport the separated solids. The present invention provides a mechanical transport device that includes a vertical screw blade rotatably housed in a solid material transport cylinder, a return hole formed in the screw blade, and a return hole formed on the side surface of the solid material transport cylinder. By circulating a portion of the solids between the solid-liquid separator and the solid-liquid separation tank through the return discharge hole, the efficiency of removing organic particles and other particulates is increased and solid-liquid separation is performed. This is what I did.

An example of a device for discharging precipitated solids is shown in Figure 1.
1 is a gravity solid-liquid separation tank. The liquid to be treated flows in through the inflow pipe 2, the solids in the liquid are separated into solid and liquid in the solid-liquid separation tank 1, and the liquid is discharged from the outlet 3. The solid matter is deposited at the bottom of the tank as precipitated solid matter, and is scraped up and carried out by a number of buckets 5 suspended from cables 4. The precipitated solids carried out by the bucket 5 are carried out of the system by a belt conveyor 6 installed above the solid-liquid separation tank 1. The cable 4 of the unloading device is driven by a transmission gear 7, and the cable 4 is guided by a pulley 8. Further, 9 is a driving device.

In the above-mentioned conventional precipitated solid material transport device,
Due to the structure of the device, the bucket 5 cannot separate the precipitated solids from the liquid, and the organic particles adhering to the precipitated solids are also carried out as they are, and the solids are removed after a separate particle separation operation outside the tank. This method has the disadvantage that it requires a double operation process of transporting it out of the system.
Furthermore, the power required for the unloading device is the power required for scraping up the precipitated solids, the power for transporting it, and the power required for the organic particulate peeling operation, but most of this is consumed by the unloading unit and the particulate peeling operation. ,
In particular, when carrying out the solids using the bucket 5, the liquid must also be carried out at the same time, resulting in a large loss of power.

The present invention has been made for the purpose of eliminating the drawbacks of the conventional precipitated solid material transporting devices described above, and allowing a single device to perform the two functions of transporting precipitated solids and removing fine particles attached to the solid materials at the same time. It is something that

The precipitated solids transport device according to the present invention includes a solids transport cylinder having an open end in contact with the precipitated solids layer in the solid-liquid separation tank at the lower end and a solids transport port at the upper end, at the liquid level of the liquid to be treated. installed almost vertically to
A screw blade is disposed in this solid material delivery cylinder, and a drive device is attached to the screw blade to rotate the screw blade at a rotational speed that allows centrifugal separation of the liquid from the solid material on the screw blade. forming a return hole having a sufficient pore diameter to allow a portion of the solid matter and the centrifuged liquid containing the exfoliated fine particles to fall in the screw blade connected to the screw blade at an appropriate height; A return discharge hole is formed on the side of the solid matter discharge tube and has a hole diameter sufficient to discharge a part of the solid matter and the centrifuged liquid containing exfoliated fine particles to the outside of the tube. It is. With the above configuration, by rotating the screw blade, the liquid and fine particles attached to the solid are centrifuged, and the separated liquid and fine particles are passed through the return hole and the return discharge hole to the solid and solid. By returning only the solids to the separation tank and transporting them out of the system, part of the solids are dropped downward through the return hole and returned to the solid-liquid separation tank through the return discharge hole for circulation. The peeling operation is repeated to increase the peeling efficiency of fine particles attached to solid objects.

The embodiments of the present invention shown in FIGS. 2 and 3 will be described in detail below.

In the embodiment shown in FIG.
The precipitated solids are transported out by the transport device 10 according to the present invention, which is arranged approximately in the center of the tank.

The unloading device 10 includes a cylindrical vertical solids unloading tube 13 that is installed in a direction substantially perpendicular to the liquid surface of the liquid to be treated in the solid-liquid separation tank 11. The open end 13A is in contact with the material layer 12, and the solid material outlet 14 is formed at the upper end.
is connected to. In the illustrated embodiment, the solid material delivery tube 13 is composed of parts 13a to 13d. In this embodiment, each of these parts 13
Although a to 13d are constructed by joining them together as separate structures, it goes without saying that they may be constructed from a single steel pipe. A rotary shaft 17 provided with a threaded blade 16 is disposed within the solid material delivery tube 13 over substantially its entire length. The screw blades 16 are formed to have a blade angle that matches the physical properties of the precipitated solids.

By the way, in the solid material delivery tube 13, the lowest portion indicated by 13a is a solid material delivery portion that sends the precipitated solids upward from the open end 13A. Further, 13c is a return section provided with a return discharge hole 15 for returning a portion of the solids sent upward and a liquid containing fine particles separated by the solid-liquid separation operation to the solid-liquid separation tank 11. As shown in FIG. 3, holes (holes for return) 16a are formed in the threaded blade 16 in this return portion 13c, and during solid-liquid separation operation, part of the solids and solid-liquid separated A liquid containing fine particles is allowed to fall through this hole 16a, and a portion thereof is returned to the solid-liquid separation tank 11 through a return discharge hole 15. Solid material delivery tube 1
The part indicated by 13d in FIG. 3 is a solid material discharge section that transports the solid material separated into solid and liquid using a screw blade and carries it out from the solid material discharge port 14. In addition, the solid material feeding section 1
Portion 13b sandwiched between 3a and return section 13c
is a portion that holds the bearing 18 of the rotating shaft 17 of the screw blade 16. The upper end of the rotating shaft 17 is connected via a suitable transmission mechanism 19 to a drive device 20 that rotates the screw blade at a rotational speed that allows centrifugal separation of liquid from solid matter on the screw blade. Note that 21 is an inflow pipe, 22 is an outlet, and 23 is a belt conveyor.

Next, the operation process will be explained. Since the lower part of the gravity-type solid-liquid separation tank 11 is conical, the precipitated solids gather at the center of the lower part of the tank, and are transferred to the solids transport tube 1 along with the liquid.
The solid material is fed into the solid material feeding section 13a of No.3. The fed precipitated solids and liquid move vertically on the surface of the screw blade 16 while being centrifuged. During this centrifugal separation operation, fine particles such as organic fine particles adhering to the precipitated solid are separated from the solid by centrifugal force and collision/friction between solid particles and particles. A part of the solids and the separated liquid are transferred to the return section 13 during the vertical movement process.
At c, the solids fall through the return holes 16a provided in the screw blade 16 onto the screw blade 16 in the pitch below, and the solids thus fallen are subjected to centrifugal separation again. That is, the residence time of the solids in the return section 13c increases, and the degree to which the fine particles are peeled off increases accordingly.

Return discharge hole 1 provided at the bottom of the return section 13c
5, a part of the solid matter, the liquid separated from the solid-liquid in the return section 13c, and the separated fine particles are discharged into the solid-liquid separation tank 11. As the operation progresses, the solids that have been centrifuged and discharged from the discharge hole 15 are sent into the cylinder again from the solids return section 13a and the centrifugation operation is repeated again.
In addition to the repeated centrifugal separation operation due to part of the solid matter falling in step 3c, the effect of peeling off the adhered fine particles is further increased.

The solids from which the fine particles and differentials in the precipitated solids have been removed in the manner described above are transported upward by the screw blades 16 and discharged from the solids discharge port 14, and then transferred to the outside of the solid-liquid separation tank 11 by the belt conveyor 23. brought out.

The results of using an example of a manipulation experiment in the present invention on urban sewage will be explained.

As is known, sewage treatment equipment removes solids contained in sewage by classifying them into fine sand with a particle size of 0.2 mm or more and other particles, and performs primary treatment to remove these solids. It's called a process.

Among the above-mentioned processing steps, during the sand removal operation, the organic fine particles adhering to the sand cause decomposition after being carried out of the system, which is a major problem on the processing equipment. Therefore, in this experiment, the blade angle and rotation speed of the screw blade 16 were treated as a function of the internal friction coefficient of the sand removal material in the range of 15 to 25 degrees, and the return hole 16
A was set to a return range of around 50% of the vertical feed amount of the screw blade 16 for each pitch, and the discharge amount of the return discharge hole 15 was also set within that range.

The experimental results under the above conditions are as follows:
The content of organic fine particles in the sand carried out from No. 4 was almost negligible, and the amount of solid matter with a diameter of 0.2 mm or less was almost negligible.

Next, using the precipitated solids taken out of the system by the belt conveyor 6 shown in FIG. 1 in a known sewage treatment device as a sample, only the lower conical portion of the solid-liquid separation tank 11 of the device of the present invention was fabricated. I conducted an experiment with this. As a result, good results were obtained that were almost consistent with the experiments described above.

The precipitated solids taken out of the system as samples for this experiment were sediment from the settling basin of the sewage treatment plant in City A, and its physical properties were as follows: particle size 300μ according to Gaudin's equation.
m, index: about 3.0, and the amount of water for settling and cleaning was set to be in the range of 2 to 6 times the amount of settled sand carried out from the solid material carrying out port 14.

As described above, according to the present invention, a portion of the solid material is dropped from the return hole formed in the screw blade onto the screw blade below and subjected to repeated centrifugal separation, and the solid material is transferred to the side surface of the solid material delivery tube. After some of the solids are discharged outside the cylinder through the formed return discharge hole, they are taken in again and subjected to centrifugation, so that the solids taken into the cylinder are cyclically and repeatedly centrifuged as a whole. As a result, fine particles such as organic fine particles attached to the solid material can be peeled off from the solid material with extremely high efficiency.

Further, according to the present invention, under the conditions of appropriate blade angle and blade rotation speed, by changing the position of the solid material return hole of the vertical screw blade in the radial direction of the screw blade, the solid material can be transported out. The critical particle size of
This means that the classification of solids can be set arbitrarily. Furthermore, the above-mentioned peeling efficiency of the adhered fine particles is made possible by varying the amount of the returned solids depending on the size and number of the solid material return holes and the size of the return discharge holes. Furthermore, as is clear from Figures 1 and 2, due to the structural characteristics of the unloading device, the installation area of the device is small, and the entire device can be simplified, and a reduction in equipment costs can be expected, and as a result of this simplification. , the reduction in total operating power is obvious.

Furthermore, as is clear from the experimental results mentioned above,
By installing the device of the present invention in an existing device, operations for removing organic substances, such as peeling off organic fine particles of precipitated solids and organic matter attached to precipitated particles, which could not be separated conventionally, are possible.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional gravity-type solid-liquid separation tank for operation of the solid-liquid separation tank. FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a partially enlarged vertical cross-sectional view of the apparatus shown in FIG. 2, and FIG. 4 is a cross-sectional view of FIG. 3. 10...Solid-liquid separation device, 11...Solid-liquid separation tank,
13...Solid material delivery tube, 14...Solid material delivery port,
15... Return discharge hole, 16... Screwed blade, 16
a... Return hole, 17... Rotating shaft, 21... Inlet, 22... Outlet, 23... Belt conveyor.

Claims (1)

[Claims] 1. A solids transport cylinder, which has an open end in contact with the precipitated solids layer in the solid-liquid separation tank at its lower end and a solids transport port at its upper end, is installed in a direction almost perpendicular to the surface of the liquid to be treated. A screw blade is disposed in the solid material delivery cylinder, and a drive device is connected to the screw blade to rotate the screw blade at a rotational speed that allows centrifugal separation of liquid from the solid material on the screw blade. Then, a hole for return is formed in the threaded blade at an appropriate height with a sufficient pore size to allow a part of the solids and the centrifuged liquid containing the exfoliated fine particles to fall, and A precipitated solid, characterized in that a return discharge hole having a sufficient hole diameter to discharge a part of the solid and a centrifuged liquid containing exfoliated fine particles to the outside of the cylinder is formed on the side of the substance discharge cylinder. Equipment for transporting goods.