Sludge discharge apparatus for settling tanks

Abstract

The present invention relates to a discharge apparatus (1) in the form of a spiral pipe (10) having the geometry of a snail enclosing an inlet (12) opened all-round along the lower periphery of the sludge hopper for the diffuse and uniform discharge of solids (sludge) settled in the settling tank (100) from the tank.

Description

[0001] SLUDGE DISCHARGE APPARATUS FOR SETTLING TANKS

[0002] Technical Field of the Invention

[0003] The invention relates to a discharge apparatus for use at the outlet of settling tanks, from which settled solids at the tank base are discharged.

[0004] State of the art regarding the invention

[0005] Settling tanks operate according to a separation / clarification principle based on the principle that the solids with high specific gravity in water and similar liquids are separated from the liquid phase due to gravity and settle to the base of the tank and the solids (sludge) settled on the base are removed from the tank.

[0006] Settling tanks are usually circular in plan with a radial slope of the base towards the center, and a small volume in the form of an inverted cone called a sludge hopper is also formed in the center of the tank base. The wastewater suspension entering the tank from the center is radially distributed to the tank from a certain depth after being regulated in the inlet structure. After the wastewater is retained in the settling tank for a certain period of time, the solid and liquid phases are separated. The sludge accumulated on the base is swept by scrapers and directed to the sludge hopper in the center of the tank. The sludge accumulated in the sludge hopper is transferred through a pipe from the outlet opened on the side of the sludge hopper to the hopper containing the pumps that remove the sludge from the system and removed from there.

[0007] When the solid matter in the suspension taken into the settling tank settles, a dense layer of sludge called a sludge blanket is formed at the base of the tank. It is not desired that this layer rises and solids overflow from the weirs where the purified water exits, or that it decreases and the settled water is discharged from the sludge outlet. Therefore, it is important to preserve this layer.

[0008] In systems known in the art, the flow rate is limited for layer conservation, this is because if the flow rate is increased, the thickened sludge layer at the base of the tank is gouged out and the thickened sludge and the settled / separated water on top of this layer are drawn through the discharge pipe below and the density of the discharged sludge is reduced. Both the discharge of clarified water from the sludge discharge pipe and the withdrawal of low concentration sludge from the tank are undesirable. In the literature, this problem is referred to as downstream short circuit. For this reason, the settling tanks are operated with a lower sludge loading rate; they are also allowed to draw sludge from the discharge pipe at a lower rate. Accordingly, larger and / or more numerous, slower operating, final settling tanks are used.

[0009] In addition, in circular final settling tanks, the sludge hopper where the settled sludge is collected and the sludge pump hopper can only be connected to each other by a single pipe. If the number of pipes is increased, the problem arises that each pipe connects the two chambers following separate trajectories without overlapping each other; in this case, the continuous and local load losses in the pipes are not equal due to the different lengths of the pipes and the different number of fittings such as elbows or goosenecks used in the manufacture of the pipes.

[0010] In the invention disclosed in publication number US6371308B1, a system for the removal of particles accumulated in the tank base is also proposed. Here, the sludge accumulated on the tank base is collected by sludge collection tubes. Collection tubes are positioned concentrically on the tank base. The sludge enters the sludge collection tubes through many small holes distributed on the tubes. The sludge in each collection tube is connected to each other and to the outlet by pipes running radially to convey the sludge to the main outlet.

[0011] Settling tanks are described in patent documents with publication numbers US2013193088A1 and KR100772121B1. In these inventions, a snail-shaped structure is used and the snail structure is provided at the part where the sludge enters the settling tank.

[0012] As a result, all abovementioned problems have made it necessary to make an improvement in the relevant technical field.

[0013] Aims of the Invention

[0014] The main aim of the present invention is to increase the flow rate without increasing the probability of damage (scouring, dispersion) to the solids layer at the base of the settling tank.

[0015] The aim of the present invention is to increase the settling tank capacity by increasing the flow rate. Brief Description of the Invention

[0016] In this invention, the sludge hopper and the hopper with the sludge pumps are connected by a single pipe. However, the end of the pipe facing the sludge hopper is bent along the wall of the sludge hopper, giving it a spiral shape, instead of sludge extraction from the cross- sectional surface of the pipe and from a single point, it is ensured that the sludge extraction can be carried out in a uniform and distributed manner from every point along the bottom wall of the sludge chamber through a narrow slit opened on the side face of the pipe.

[0017] Furthermore, the cross-sectional area in the spirally shaped part of the pipe is uniformly reduced along the circumference of the sludge hopper so as to keep the flow velocity constant along the spiral trajectory and accordingly the flow pattern is ensured.

[0018] In addition, a narrow mouth is formed so as to regulate the entry of fluid (sludge) into the slit cut into the side face of the mentioned pipe. Guiding fins are formed in the mouth at a certain distance from each other and at a certain angle. These fins direct the fluid passing through the slit into the spiral pipe at an optimum angle, allowing the fluid passing through the slit to participate in the flow in the pipe without damaging the flow pattern in the spiral pipe.

[0019] Definitions of the Figures Describing the Invention

[0020] The figures and related explanations used so as to better explain the device developed with the present invention are given below.

[0021] Figure 1. Section of isometric perspective view of the settling tank and discharge apparatus of the present invention

[0022] Figure 2. A plan view of the discharge apparatus of the present invention

[0023] Figure 3. Isometric perspective view of the discharge apparatus of the present invention

[0024] Definitions of Elements / Sections / Parts that Constitute the Invention

[0025] The parts and parts in the figures are enumerated and the corresponding of each number is given below in order to better explain the device developed with this invention:

[0026] 1. Discharge apparatus

[0027] 10. Spiral pipe

[0028] 11. Outlet

[0029] 12. Inlet

[0030] 13. Guiding fins 14. Mouth

[0031] 100. Settling tank

[0032] 110. Side wall

[0033] 120. Tank base

[0034] 130. Sludge hopper

[0035] 140. Inlet structure

[0036] 150. Settlement zone

[0037] C. Spiral pipe rotation axis

[0038] CS. Cross sectional area

[0039] OD. Outer diameter

[0040] ID. Inner diameter a. Plate angle

[0041] Detailed Description of the Invention

[0042] The present invention relates to a discharge apparatus (1) for discharging solids (sludge) from a settling tank (100) in a diffuse and uniform manner.

[0043] Referring to Figure 1, the mentioned settling tank (100) is surrounded by a side wall (110). The tank geometry is preferably cylindrical or circular in plan, arranged to ensure containment of the fluid to be treated. The suspension to be settled is taken from the inlet structure (140) to the settlement zone (150).

[0044] The suspension, which is de-energized as it leaves the inlet structure, is retained in the settlement zone (150) for a sufficient time so as to settle the solids heavier than water in the suspension. Settled solids form sludge on the tank base (120).

[0045] The solids accumulated on the tank base (120) are swept by a scraper bridge and directed to the sludge hopper (130) having inverted cone geometry formed in the center of the tank base.

[0046] In known systems, the solids accumulated in the tank are discharged through a straight pipe connected to the side of the sludge hopper (130). In the tank according to the invention, however, the settled solids are discharged through a narrow slit cut all around the lower periphery of the sludge hopper (130). In order to collect the sludge leaving the tank through the slit, a discharge apparatus (1) was constructed surrounding the slit. Referring to Figure 2, said discharge apparatus (1) comprises a spiral pipe (10). The spiral form here is snail geometry. The spiral pipe (10) is designed to be connected by encircling the slit (12) cut along the bottom wall of said sludge hopper (130).

[0047] The solids entering the discharge apparatus (1) through the slit (12) opened along the bottom wall of the sludge hopper (130) in the direction indicated by the guide fins (13) move from the closed end to the open end inside the spiral pipe and reach the outlet (11).

[0048] One end of the spiral pipe (10) is arranged as an outlet (11) and is open, while the other end is closed. Preferably, the mentioned end is provided physically closed or directly connected to a surface of the spiral pipe (10).

[0049] The spiral pipe (10) is rotated around the central axis of the settling tank (100) and the central axis of the settling tank coincides with the axis of rotation (C) of the spiral pipe. An inlet (12) is arranged to allow fluid to flow through the spiral pipe (10) through a slit cut along the inner surface of the spiral pipe facing the axis of rotation (C), i.e. along the inner diameter (ID) or at least part of the inner diameter (ID) along the lower wall of said sludge hopper (130). The mentioned inlet (12) is preferably in the form of a slit.

[0050] In a preferred embodiment of the invention, the said inlet (12) is arranged so that the slit, which is opened symmetrically upwardly and downwardly equidistantly from the plane passed through the center of the spiral pipe (10), preferably extends over the entire inner surface.

[0051] In conventional systems, the solids leave the tank at a single point through a pipe; in the said system, the solids leave the tank in a diffuse and uniform manner through a long and narrow slit cut along the bottom perimeter of the sludge hopper.

[0052] Accordingly, the present discharge apparatus (1) comprises a spiral pipe (10) having a single outlet (11) and at least one inlet (12) extending along at least a portion of the inner diameter (ID) of the spiral pipe (10) to allow fluid to enter the said spiral pipe (10).

[0053] More specifically, said discharge apparatus (1) is a spiral pipe (10) having a single outlet (11), closed at one end and open at the other end, rotated about the center of the settling tank (100) and the spiral pipe rotation axis (C), said spiral pipe (10) comprises at least one inlet (12) extending at least partially along the inner diameter (ID) of said spiral pipe (10) facing the axis of rotation (C).

[0054] With reference to Figures 2 and 3, said discharge apparatus (1) comprises at least one guiding fin (13) angled relative to an imaginary line extending from the inlet (12) towards the outer diameter (OD) of the spiral pipe (10) and extending in a radial direction so as to direct the fluid passing through the inlet (12) towards the outlet (11). Here, the radial direction is taken with respect to the spiral pipe rotation axis (C).

[0055] In the preferred embodiment of the invention, a narrow opening (14) is formed immediately in front of the inlet (12) to the spiral pipe to regulate the entry of the fluid (sludge). Guiding fins (13) are formed in the mouth (14) at a certain distance from each other and at a certain angle. Said guiding fins (13) ensure that the fluid entering the spiral pipe (10) participates optimally in the spiral flow in the spiral pipe (10). For this reason, the guiding fins (13) are angled so as to ensure the most appropriate participation of the fluid entering the flow in the spiral pipe. In Figure 2, the movement direction of the fluid entering the spiral pipe (10) through the guiding fins (13) is shown with dashed arrows. Here, the fluid is directed to the discharge apparatus

[0056] (I) in the direction of the dashed vertical arrow in Figure 3, and then enters the spiral pipe (10) in the direction of the arrows in Figure 2.

[0057] If there are no guiding fins (13), smooth flow conditions will not occur within the spiral pipe (10).

[0058] Said guiding fins (13) are angled from the rotation center (C) of the spiral pipe towards the outlet (11). The angle mentioned here is provided according to an imaginary line extending in the radial direction so as to direct the fluid passing through the inlet (12) towards the outlet

[0059] (I I). To illustrate with Figure 2, it is assumed that an imaginary longitudinal line passes through the center of rotation (C) of the spiral tube. Furthermore, the lines extending radially from the center of rotation (C) of the said spiral tube with respect to the first imaginary line are assumed to be imaginary lines. A plate angle (a) is formed between the radial imaginary lines intersecting the end of the guiding fins (13) close to the center of rotation (C) of the spiral pipe and the guiding fins (13). The angled orientation of the guiding fins (13) described above provides the plate angle (a) mentioned. Referring to Figure 3, in a preferred embodiment of the invention, since it is difficult to give the discharge apparatus (1) the form of a spiral of increasing diameter, said spiral pipe (10) is formed of truncated cone-shaped plates articulating with each other. The cross-sectional areas (CS) of the truncated cones, which articulate with each other to form the spiral pipe (10), increase towards the outlet (11). The cross-sectional area (CS) mentioned here refers to an area perpendicular to the flow direction in the spiral pipe (10). Since the fluid enters said spiral pipe (10) axially from the inlet (12) opened on the side face, the last conical segment towards the outlet (11) contains the fluid entering the spiral pipe (10) from the inlets (12) in the preceding conical segments together with the fluid entering the spiral pipe (10) from the inlets (12) in this segment and traveling through the spiral pipe (10) and arriving at the outlet (11). For this reason, the segment close to the outlet (11) has more fluid by volume. As a solution, the cross-sectional area (CS) of the spiral pipe (10) increases continuously or gradually towards the outlet so as to ensure smooth flow conditions.

[0060] It has already been described that the said inlet (12) opens along the inner surface (ID) of the spiral pipe (10) facing the spiral pipe rotation axis (C). In the preferred embodiment of the invention, the surface of the said slit is planar except for the curvature caused by the rotation provided by the spiral pipe (10). In other words, the inner diameter (ID) portion where the said inlet (12) is located is provided on a wall provided with a linearly cut portion and in the direction of this cut. Here, a mouth (14) having an inner diameter (ID) portion is configured such that said mouth (14) can be connected to the said sludge hopper (130).

[0061] With reference to Figure 1, preferably the base (120) of the settling tank (100) is arranged radially sloping towards the center; thus, as the solids accumulated on the base (120) are swept by the scraper bridge, they move towards the center of the tank / tank outlet towards the sludge hopper (130). The sludge hopper (130) is a small inverted cone-shaped volume in the center of the settling tank (100), attached to the settling tank (100) in such a way that the upper elevation of the sludge hopper (130) and the lower elevation of the tank base (120) coincide. Both in the known systems and in the mentioned system, the solids are discharged from the sludge hopper (130). A slit along the bottom wall of the sludge hopper (130) is connected to the discharge apparatus (1). The geometry of the sludge hopper (130) ensures controlled delivery of the settled solids to the discharge apparatus (1). A scraper bridge may also be formed to promote the movement of solids accumulated on the base (120) of the settling tank (100) to the sludge hopper (130). The scrapper bridge consists of a drive element and at least one, preferably a plurality of, scraper moving around the central axis of the settling tank with the force provided by the said drive element. In a preferred embodiment, the said drive element is a motor providing rotational motion. These scrapers extend radially to the drive element.

[0062] These scrapers ensure the movement of the sludge accumulated at the tank base (120) from the side wall of the tank (110) towards the sludge hopper (130).

Claims

CLAIMS1. A discharge apparatus (1) for use in the sludge hopper (130) of the settling tanks (100), characterized in that, it comprises the following;- a spiral pipe (10) having an outlet (11),- at least one inlet (12) extending along at least part of the inner diameter (ID) of the spiral pipe (10) so as to allow fluid to enter the said spiral pipe (10).

2. A discharge apparatus (1) according to claim 1, characterized in that, it is provided to extend over the said entire inner diameter (ID).

3. A discharge apparatus (1) according to claim 1, characterized in that, it comprises at least one guiding fin (13) angled relative to an imaginary line extending from the said inlet (12) towards the outer diameter (OD) of the spiral pipe (10) and extending in a radial direction to direct fluid passing through the inlet (12) towards the outlet (11).

4. A discharge apparatus (1) according to claim 3, characterized in that, it comprises a plurality of guiding fins (13).

5. A discharge apparatus (1) according to claim 4, characterized in that, said guiding fins (13) are radially distributed in a spaced manner.

6. A discharge apparatus (1) according to claim 4 or 5, characterized in that, said guiding fins (13) are evenly distributed.

7. A discharge apparatus (1) according to claim 1, characterized in that, the cross-sectional area (CS) of the said spiral pipe (10) is arranged to increase towards the outlet (11).

8. A discharge apparatus (1) according to claim 1, characterized in that, the inner diameter portion (ID) of the inlet (12) of the said spiral pipe (10) is provided in the form of a planar wall.

9. A discharge apparatus (1) according to claim 1 or 8, characterized in that, the inner diameter (ID) portion of the said spiral tube (10) is configured to be connected to the sludge hopper (130).

10. A settling tank (100) comprising a discharge apparatus (1) according to any one of the preceding claims.

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