JPH10118531A - Bottom material separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate bottom materials with decreased driving power without requiring many cyclones by providing a cylindrical vessel with an inflow port for water contg. the sand and soil from a pump and an inflow port for pressurized water contg. a satd. air quantity in the tangent direction of the vessel and providing the top end of the cylindrical vessel with an outflow port and the bottom end of a conical shape of the lower part with an outflow port for grain. SOLUTION: A tower I handles three phases; solid, gas and liquid and is a kind of centrifugal separator. A tower II installed behind the tower I is also a similar centrifugal separator. The excavated sand and soil 6 flowing into the tower I flow into the inflow port 7 via a pump 3. Besides, the pressurized water 4, 5 which dissolves air, oxygen or oxygen-rich air to supersaturation flow into the respectively inflow ports 8, 9. In such a case, the pressurized water 4, 5 are admitted by the pump as well. The water discharged from the tower I is discharged together with the sand and soil of large grain sizes from the discharge port 12 at the bottom end. A mixture composed of micro-air bubbles, fine grain size sand and soil and org. component flows out of an outflow port 10 at the top end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment device for removing suspended particles contained in raw water of waterworks, or a device for improving soil quality on a water bottom, such as a device for cleaning lower sediment of a fish farm in a sea area or a device for improving sediment quality. And the like.

[0002]

2. Description of the Related Art Conventionally, soil modification of water bottoms such as rivers and seas has not been carried out at present, and underwater concrete such as landfills is used for dredging and removing water bottom soil as necessary. And hardening by draining water from the soil with a sand drain. There are methods using filters and multi-stage cyclones for the removal of fine particle size particles and particles containing organic components from sediment.However, in the case of filters, problems such as clogging and wear can be ignored. Low practicality.

For this reason, attention is paid to a structure in which cyclones are arranged in multiple stages. FIG. 10 illustrates the principle and the shape of the cyclone. As shown in FIG. 10 (a), the cyclone has an internal flow state in which the undiluted solution flows in from the tangential direction of the cylindrical portion to generate an eddy, A swirling flow is generated and coarse particles and liquid are discharged from the lower end outlet of the conical portion, and fine particles and liquid are discharged from the upper end outlet by the upward swirling flow in the center portion. For a standard cyclone, the diameter D _{C of the} cyclone body is used. There is a dimensional standard based on the formula, and the separation performance pressure loss is also formulated.

In general, the flow rate of a liquid into a hydrocyclone cannot be made as high as that of a gaseous substance under the condition that the pressure loss is proportional to the square of the flow rate and no cavitation occurs in the liquid. Assuming that the inflow velocity is constant, the particle separation performance is 50% separation particle diameter D ₅₀ (the particle diameter at which 50% of the particles entering the cyclone are separated by cyclone when the group of particles entering the cyclone is classified) is cyclone. in proportion to the square root of the cylindrical diameter D _c, the pressure loss ΔH is known to be inversely proportional to the fourth power of the cyclone cylindrical diameter D _c. Therefore, it is attempted to reduce the 50% separation particle size by one order of magnitude, that is,
If the particle size that can be separated by 0% is reduced to 1/10, the cyclone cylinder diameter becomes 1/100 and the pressure loss becomes 10 ⁴ times, which is not practical.

For this reason, as shown in FIG. 11, a cyclone is formed in multiple stages, and when particles are separated in the cyclone, coarse particles are separated in the first stage cyclone F.
In order to reduce the pressure loss, the liquid flow rate is divided, a second-stage cyclone S for separating medium-sized particles is provided for each of the divided liquid flows, and a third-stage cyclone T for separating fine-particles is further divided and provided. A cyclone system is used. Also in this multi-stage cyclone system,
Since the pressure loss is a total sum of the pressure losses of the cyclones in each stage, the pressure loss becomes large as a whole, and it is necessary to increase the head of the pump for flowing the liquid, and the power cost for driving this pump cannot be ignored.

[0006]

Although it is easy to remove large-diameter particles by the above-described multi-stage cyclone system, separation of micro-particles such as clayey particles containing fine earth and sand and organic components is difficult. In order to flow the desired flow rate in a short time, a large number of cyclones are required,
Problems such as cost and processing efficiency occur, and a large amount of power is required due to a large pressure loss as described above. Furthermore, there is also a problem that it is difficult to separate fine-grained soil and organic matter attached to the large-grained particles.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a sediment separation apparatus which does not require a large number of cyclones, requires less power, and achieves perfect separation.

[0008]

In order to achieve the above-mentioned object, the present invention has the following matters specifying the invention. (1) A cylindrical container having a lower conical shape is provided, an inlet for water containing earth and sand from a pump is provided tangentially to the cylindrical container, and pressurized water containing a saturated air amount is provided tangentially to the cylindrical container. An inlet is provided, an outlet is provided at the upper end of the cylindrical container, and a discharge port for particles is provided at a lower end of the lower conical shape. (2) In the above (1), the inflow port of the pressurized water is separately provided at an upper portion and a lower portion of the cylindrical container. (3) In the above (1) or (2), the inflow port of the pressurized water is movable at a desired angle with respect to the hollow axis direction of the cylindrical container. (4) In the above (1), a cylindrical container having a larger diameter than the cylindrical container is provided at an upper portion of the cylindrical container, and a discharge port is provided at a lower part around the cylindrical container having a large diameter. I do. (5) In the above (1), a cylindrical shape having a tangentially provided inlet into which water from the outlet of the tower I flows in the subsequent stage with respect to the tower I comprising the cylindrical container having the lower conical shape. Comprising a tower II having a container and a lower cone,
The tower II is characterized in that a lower conical lower end has a discharge port and an upper end has an outlet. (6) In the above (5), the tower II is provided with a bypass outlet in an upper side wall of the cylindrical container. (7) In the above (5), the tower II is arranged to be inclined. (8) In the above (1), an ejector is provided between the pump and the inlet of the water containing earth and sand in the cylindrical container. (9) In the above (1), a diffusion prevention film is provided on the dredged soil by the pump. (10) In the above (5), a sedimentation filtration tank is provided downstream of the tower II.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an example of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an overall configuration. A tower I is a kind of centrifugal separator that handles three phases of solid, gas, and liquid and is different from a conventional cyclone. Is a similar centrifuge. Excavated earth and sand 6 flowing into the tower I flows into the inlet 7 via the pump 3, while pressurized water 4, 5 in which air, oxygen, or oxygen-rich air is dissolved in supersaturation is supplied to the respective inlet 8. , 9. In this case, the pressurized waters 4 and 5 are also supplied by a pump (not shown). Further, the water discharged from the tower I is discharged together with the large-sized earth and sand from the outlet 12 at the lower end, and a mixture of micro-bubbles and fine-grained sand and organic components is discharged from the outlet 10 at the upper end. .

FIG. 2 shows the internal flow state of the tower I.
As shown in FIG. 2, at the upper part of the tower I, an inflow port 8 of the pressurized water 4 is communicated in a cylindrical tangential direction, and in an inner part of the tower I, an inflow port 7 of the earth and water 6 is communicated in a cylindrical tangential direction.
At the lower part of the tower I, an inlet 9 for the pressurized water 5 communicates in a cylindrical tangential direction.

The sediment / water 6 flowing into the tower I flows in the tangential direction of the cylindrical tower I to generate a swirling flow. Similarly, the pressurized waters 4 and 5 flow in the tangential direction of the tower I to generate a swirling flow. In this case, the pressurized water 4 emits many microbubbles at a low pressure portion near the center of the hollow shaft of the tower I,
These microbubbles are mixed with fine-grained sediment and organic matter that tend to collect in the center due to a small effect of the centrifugal force of the upward swirling flow, and adhere to the bubbles by interfacial tension. The particles further gather at the center of the swirling flow, and as a result, the particles can be easily separated from the large-sized particles adhering to the side wall of the tower I by centrifugal force. In this case, the microbubbles formed by the pressurized water 4 are preferably as small as possible to adhere small particles.
It is preferable to generate many fine bubbles having a diameter. Furthermore,
Since the pressurized water 4 also has a function of adjusting the strength of the swirling flow in the tower I together with the generation of microbubbles, the inlet 8 is not only in the horizontal direction but also in the vertical direction with respect to the horizontal direction as shown by φ in FIG. It is also necessary to reduce the turning force above the inflow port 8 by making an angle. This is necessary to weaken the swirl because the swirl flow may cause large-sized earth and sand to be discharged from the upper part if the swirl flow is too strong. The direction of the inflow port 8 may be completely opposite to the swirling flow, and the pressurized water 4 may be introduced.

The inflow port 9 is tangentially connected to the lower portion of the cylindrical tower I, and the pressurized water 5 flows in so as to generate a swirling flow. The pressurized water 5 to the inflow port 9 is
The tower I was allowed to flow at a slightly higher pressure, and a large number of microbubbles were released near the wall immediately after the tower I inflow, and vigorously mixed with the large-diameter sediment on the centrifuged wall.
Bubble mixed with fine-grained sediment and organic matter collects in the center of the surface. In this case, the bubbles of the pressurized water 5 and the fine particles or the organic components in the earth and sand are strongly mixed and adhered by the swirling turbulent flow, and the cavitation is performed by the pressurized water 5 in the large-diameter particles falling on the side wall by gravity. This causes a so-called washing action in which fine particles adhered around the large particles are peeled off and adhered to fine bubbles by cavitation.

Further, the large-diameter particles in the tower I alternately and violently collide with water and bubbles in a strong turbulence, so that there is also an effect that the fine-diameter particles on the surface of the large-diameter particles are repelled. A baffle plate 11 is disposed at an upper end portion of the tower I, and a group of bubbles collected at a central portion in the tower I is discharged from the outlet 10.
It is installed to prevent it from passing straight through. The baffle plate 11 can further increase the mixed bubbles and the adhesion effect by pushing the rising bubbles toward the side wall. Here, the position of the outlet 10 is shown in FIG.
-When placed at the upper center of the tower I as seen from the arrow A, all the energy of the swirling flow of the tower I is dissipated in the tower I. When the outlet 10 is tangential to the periphery of the tower I, part of the energy of the swirling flow is recovered and enters the connecting pipe to the tower II, which has the effect of reducing the overall pressure loss. Due to the presence of large particles, there is also the possibility that these particles will be sent to Tower II. Therefore, depending on the situation, the outlet 10
Is provided at the center of the upper end of the tower I or in the tangential direction.

The separation of the large-diameter particles and the internal flow state in the tower I are summarized as follows. Since the mixed water 6 containing organic matter and water flowing into the tower I from the inlet 7 flows in the tangential direction, a strong swirling flow is generated in the tower I, and particles having a large particle size are deposited on the side wall by centrifugation. Separated. On the other hand, near the center of the tower I, a large number of particles having a small particle size that cannot be separated by the centrifugal separation function are floating. When the pressurized water 4 is introduced here, the pressure in the vicinity of the central part is lower than that in the peripheral part, so that many microbubbles having a diameter of 20 to 30 μm are generated and adhere to floating fine particles or organic components. Further below the tower I, the pressurized water 5 has a slightly higher pressure than the pressurized water 4 and generates air bubbles on the wall immediately after inflow. This bubble is generated by cavitation,
In a swirling flow field such as a cyclone, since the wall surface has the highest pressure, the generated bubbles are not crushed at high pressure to cause wall erosion. Since the inflow port 9 for the pressurized water 5 is located below the earth and sand 6 and the water inflow port 7, centrifugally separated particles having a large particle diameter are gravitationally falling on the wall surface into which the pressurized water 5 flows. Pressurized water 5 flows into this, generating cavitation bubbles (20 to 30 μm diameter).
The fine particles and organics attached to the periphery of the large particles are repelled from the large particles, and the bubbles themselves adhere to the separated fine particles and organics, and are centrifuged to the center. It has the effect of separating and transporting. Microbubbles generated from the pressurized water 4 and 5, including fine particles and those adhering to organic components, go up through the center of the tower I to the top, and flow out of the outlet 10 to the tower II. At the same time, the separated large-sized earth and sand is discharged from the lower end discharge port 12 of the tower I.

Bubbles, fine-grained sediment, organic matter, water, and medium- and small-grained sediment flowing out from the upper end outlet 10 of the tower I are sent to the tower II and flow into the tower II through the widening inlet 13. . In Tower II, the widening inlet 13 is tangentially mounted to reduce the flow rate and generate a slow swirling flow. Here, the small particle particles that could not be separated by the tower I are separated. That is, when the mixture is introduced into the tower II from the tangential direction, a weak swirling flow is generated, and the small-diameter particles can be discharged from the lower discharge port 14 by the flotation effect of separating the particles by the specific gravity difference, and further by the separation effect by the centrifugal force. . Further, water containing fine-grained soil, organic matter, and microbubbles flows out from the upper outlet 15 and is separated. Furthermore, the outlet 15
In order to reduce the amount of water flowing out of the tower II, a bypass outlet 16 is provided in the upper part of the tower II in a tangential direction, and water is extracted and returned to the suction side of the pump 3 via a flow control valve 17. FIG. 3 shows the internal flow state of the tower II. FIG.
Shows a configuration in which Tower II is installed at an angle,
Separation efficiency is improved by small particles having a small particle diameter due to gravity reaching the wall surface of the tower II earlier than reaching the lower end of the container and being attached to the wall surface by centrifugal force, so that solid particles hardly come out from the bypass outlet 16.

The operation of the above tower II is as follows. What flows into the tower II from the inlet 13 is water, air bubbles, fine-grained sediment, organic matter, and small-grained sediment particles that cannot be completely separated by the tower I. Inflow to Tower II enters tangentially at a small velocity (less than 1 m / s) and creates a slow swirling flow within the tower. Most of the small-sized particles flowing in by this swirling flow are centrifuged. In addition, water containing bubbles gathers at the center and rises. In this process, so-called floating separation is performed in which small-sized particles contained therein settle and separate from water containing bubbles due to the effect of gravity. Due to the swirling, the fine particles and organic components attached to the bubbles collect together with many other bubbles at the center and flow out from the outlet 15. For this reason, clean water is separated and generated around the upper side wall in the tower II. In this example, this is bypassed to the suction side of the pump 3 and reused. This is because, in order to treat fine particles and organic components in the water flowing out from the outlet, the smaller the amount of transported water, the better. The internal flow phenomenon when the Tower II is tilted
This is almost the same as when the II is upright, but the smaller the particles that settle by gravity reach the lower side wall of the Tower II, the higher the efficiency of flotation separation and the smaller the particles are on one side. Is collected on the side wall of the air outlet, there is an advantage that the solid particles hardly enter the effluent from the bypass outlet 16. Outlet 1
The fluid flowing out of 5 includes water, air bubbles, fine-grained sediment, and organic components, but sometimes bypasses the water, so that an effect of air lift by the air bubbles can be expected. In this example, the pump operates underwater or on land, but when installed underwater, the effect of this air lift can reduce pump power.

FIG. 5 shows a modification of the tower I. The tower I shown in FIGS. 1 and 2 is provided with a cylindrical container 18 having a diameter larger than that of the tower I and a sediment outlet 19 at the upper part of the tower I. The upper plate 20 of this large-diameter cylindrical container 18 (referred to as a top hat disk) is formed in an umbrella shape, and its center is higher than the periphery so that air bubbles in water can flow out to the outlet 10 efficiently.
The purpose of this top hat disk is to recover medium sized particles. At the lower part of the tower I, most of the particles having a large particle diameter are recovered by the centrifugal force of the swirling flow, but there are some particles which are taken out to the upper part due to the strong swirling flow. If a top hat disk 18 is provided at the top of the tower I in order to collect the medium-sized particles taken out to the upper part, the swirl flow coming out of the tower I spreads in the top hat disk 18 and around the swirl flow, The flow velocity is greatly reduced, and the medium-sized particles adhered to the side wall by centrifugal force fall to the lower part of the periphery and are collected at the sediment discharge port 19. The tower I protrudes into the top hat disk 18, and sediment can be collected within the range of the protruding height and extracted to the outside through the sediment discharge port 19. Needless to say, the sediment discharged from the sediment discharge port 19 is washed with bubbles and water similarly to the sediment from the lower discharge port 12 of the tower I, and contains almost no fine particle particles that cause turbidity. In the tower I shown in FIGS. 1 and 2, the swirling flow tends to be strong, and therefore, it is conceivable that the recovery of the medium-sized particles is reduced. Therefore, the medium-sized particles can be collected and collected on the wall surface by the top hat disk 18 in order to improve the recovery rate of the medium-sized particles. In this case, it is possible to collect small-diameter particles instead of the tower II depending on the shape of the top hat disk 18. However, the tower II is required when it is desired to reliably separate small, medium and large particle diameters. .

FIG. 6 shows a method of taking in earth and sand different from that of FIG.
As shown in FIG. 1, instead of directly taking in a mixture of water and earth and sand, the discharge port of the pump is passed through an ejector 21 to thereby suck the dredged earth and sand 6. According to this method, the rotating blades of the pump are not damaged by abrasion due to earth and sand. Further, a wide range of earth and sand can be sucked by forming the suction line of the ejector 21 as a flexible tube.

FIG. 7 shows that when excavating and dredging earth and sand at the bottom of the water,
In order to prevent the turbid water from spreading to the surroundings, the diffusion prevention film 22 is put on an excavator (not shown), and return water (bypass water) from the tower II is put into a ring header 23 installed on the diffusion prevention film 22, A water curtain is generated around the diffusion prevention film 22 to completely prevent turbid water from being diffused by construction.

FIG. 8 shows an example of a structure for separating fine-grained sediment and organic matter from a mixture of water, air bubbles, fine-grained sediment and organic matter flowing out of the tower II.
Details are shown in FIG. Usually, two filtration tanks 24 are installed and used alternately. When not used, the filter medium is regenerated. FIG.
At first, the mixture of water, bubbles, fine-grained sediment, and organic matter flowing out of the tower II first enters the upstream tank 25, where the flow rate is reduced, and then flows into the inclined filtration material installation tank 26, The water is filtered further down, the fine-grained soil and organic components remain near the surface of the filter medium 27, and the water flows out downstream from the lower waterway 28. This water is clear water and can be discharged to any water area. For the treatment of fine-grained soil and organic matter in the water flowing out of Tower II, the particles were collected electrically,
A method of performing organic treatment by biotechnology is also conceivable.

In the above description, pressurized water 4,5
Is shown from the separate inlets 8 and 9, but the separation function can be exhibited only by adding the pressurized water 4 from the inlet 8 without separating the pressurized waters 4 and 5. Therefore, the tower I may be obtained as a structure excluding the inflow port 9.

[0022]

As described above, according to the present invention, in order to efficiently separate large-size particles and medium- and small-size particles from earth and sand, it is necessary to use a large number of cyclones as in the prior art. Maintenance is simple and the power of the suction pump is smaller than before. Furthermore, a mixture of excavated sediment and water is obtained by combining the effect of centrifugal separation by swirling flow, the effect of cavitation cleaning by pressurized saturated water, and the effect of flotation separation using microbubbles, fine particles, and organic matter. Can separate only fine particles and organic matter in the soil from water, and the large particles discharged do not contain fine particles and organic matter even if stirred in water, so there is no turbidity at all, In this respect, the particles did not become turbid like particles separated by a conventional cyclone, and the separation performance was remarkably improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an example of an embodiment of the present invention and a view taken from an arrow of each part.

FIG. 2 is an internal flow schematic diagram of the tower I of FIG.

FIG. 3 is a schematic diagram of the internal flow of the tower II of FIG.

FIG. 4 is an internal flow schematic diagram when the tower II is inclined.

FIG. 5 is a configuration diagram showing another example of the tower I.

FIG. 6 is an overall configuration diagram including an ejector.

FIG. 7 is an overall configuration diagram including a diffusion prevention film.

FIG. 8 is an overall configuration diagram including a sedimentation filtration tank.

FIG. 9 is a mechanism diagram of the precipitation filtration tank of FIG.

FIG. 10 is a diagram showing the shape and flow of a conventional cyclone.

FIG. 11 is a conceptual diagram of a conventional cyclone system.

[Explanation of symbols]

 I, II Tower 3 Pump 4,5 Pressurized water 7,8,9 Inlet 10,15 Outlet 11 Baffle plate 12,14 Outlet 13 Widening inlet 16 Bypass outlet 18 Cylindrical vessel (top hat disk) 19 Sediment outflow outlet Reference Signs List 20 upper plate 21 ejector 22 diffusion prevention film 23 ring header 24 sedimentation filtration tank

Claims (10)

[Claims] 1. A cylindrical container having a lower conical shape, an inlet for water containing earth and sand from a pump in a tangential direction of the cylindrical container, and a saturated air amount in a tangential direction of the cylindrical container. A sediment separation device comprising: an inlet for pressurized water; an outlet at the upper end of the cylindrical container; and an outlet for particles at a lower end of the lower conical shape. 2. The sediment separation apparatus according to claim 1, wherein the inflow port of the pressurized water is separately provided at an upper portion and a lower portion of the cylindrical container. 3. The sediment separation apparatus according to claim 1, wherein the inlet of the pressurized water is movable at a desired angle with respect to the direction of the hollow axis of the cylindrical vessel. 4. The sediment separation according to claim 1, wherein a cylindrical container having a diameter larger than the cylindrical container is provided at an upper part of the cylindrical container, and a discharge port is provided at a lower part around the cylindrical container having the large diameter. apparatus. 5. A cylindrical container having a cylindrical container having a lower conical shape and an inlet in which water from an outlet of the tower I flows tangentially provided in a subsequent stage with respect to the tower I formed of a cylindrical container having a lower conical shape. A tower II having a shape
2. The sediment separation apparatus according to claim 1, wherein the lower conical bottom has a discharge port at the lower end and an outlet at the upper end. 6. The sediment separation apparatus according to claim 5, wherein said tower II is provided with a bypass outlet in an upper side wall of said cylindrical vessel. 7. The sediment separation apparatus according to claim 5, wherein said tower II is disposed at an angle. 8. The sediment separation apparatus according to claim 1, further comprising an ejector provided between the inlet of the water containing earth and sand in the cylindrical container and the pump. 9. The sediment separation apparatus according to claim 1, wherein a diffusion prevention film is covered on the dredged soil by the pump. 10. The sediment separation apparatus according to claim 5, further comprising a sedimentation filtration tank at a stage subsequent to the tower II.