A radial flow type circumferential inlet and outlet secondary sedimentation tank with additional middle outlet

Abstract

The present invention relates to a radial flow type peripheral inlet and outlet secondary sedimentation tank with an additional intermediate water outlet. The peripheral water distribution system is used to introduce muddy water into the tank body from the periphery of the tank body. The peripheral water outlet system is used to discharge the clean water obtained after the muddy water is precipitated from the tank body from the periphery of the tank body. The intermediate water outlet system is used to discharge the clean water obtained after the muddy water is precipitated from the tank body into the peripheral water outlet system from the middle area of ​​the tank body. After the muddy water enters the tank body, it is discharged from the tank body after settling along the first path or the second path according to its specific gravity. The first path is that the muddy water flows through the peripheral radial flow area and settles, and the clean water formed is discharged into the peripheral water outlet system. The second path is that the muddy water flows through the peripheral radial flow area and the intermediate radial flow area in turn and settles, and the clean water formed is merged into the intermediate water outlet system and then discharged into the peripheral water outlet system. The muddy water with a lighter specific gravity flows from the peripheral radial flow area to the intermediate radial flow area for sedimentation and the clean water formed by the sedimentation is discharged into the intermediate water outlet system. The intermediate water outlet system can also alleviate the interference of external wind.

Description

Technical Field

[0001] The invention relates to the technical field of muddy water sedimentation, and in particular to a radial flow type circumferential inlet and outlet secondary sedimentation tank with an additional intermediate water outlet. Background Art

[0002] At present, most of the secondary sedimentation tanks in my country's mud and water treatment plants adopt radial flow circumferential inlet and outlet tanks, that is, the water inlet and outlet mechanisms of the secondary sedimentation tank are set around the sedimentation tank. The radial flow circumferential inlet and outlet secondary sedimentation tank has a unique annular flow pattern. Muddy water enters from the circumference of the sedimentation tank and flows toward the center of the sedimentation tank. The muddy water flows to the muddy water on the opposite side and then turns back. During the flow of muddy water, the heavier sludge sinks to the bottom of the tank, and the clean water flows upward to the clean water area at the top of the sedimentation tank, and then flows into the water outlet mechanism around the sedimentation tank. However, during use, the traditional radial flow type circumferential inlet and outlet secondary sedimentation tank has the following disadvantages: (1) The sedimentation efficiency in the center area of ​​the sedimentation tank is low: In theory, when the muddy water enters the sedimentation tank from the circumference and flows to the center of the sedimentation tank, the muddy water will flow to the center of the sedimentation tank and meet the opposite water flow before returning to the circumference of the sedimentation tank. However, in reality, the water flow in the tank body is large, and the muddy water will meet the muddy water on the opposite side and return before flowing to the center of the sedimentation tank. This will cause a large area in the center of the sedimentation tank to not participate in the flow and sedimentation of the muddy water, and it is an invalid sedimentation area, resulting in low sedimentation efficiency in this area. (2) The diameter size of the sedimentation tank is limited: If the diameter of the sedimentation tank is large, it is easy to be affected by the wind to form waves in the sedimentation tank, which will affect the flow state and sedimentation effect of the muddy water in the sedimentation tank. Therefore, the diameter size of the sedimentation tank is limited and can only be set to a maximum of 50m, which makes it difficult to expand the size and increase the amount of muddy water sedimentation. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a radial flow type circumferential inlet and outlet secondary sedimentation tank with an additional intermediate water outlet, which solves the technical problems of low sedimentation efficiency in the central area of ​​the sedimentation tank and limited diameter size in the traditional radial flow type circumferential inlet and outlet secondary sedimentation tank.

[0005] (II) Technical solution

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] The embodiment of the present invention provides a radial flow type peripheral inlet and outlet secondary sedimentation tank with an additional intermediate outlet, comprising a tank body, a peripheral water distribution system, a peripheral outlet system, and an intermediate outlet system;

[0008] The inner cavity of the cell body includes a peripheral radial flow area and a middle radial flow area;

[0009] The peripheral water distribution system is used to introduce muddy water from the periphery of the pool body into the pool body; the peripheral water outlet system is used to discharge clean water obtained after the muddy water settles from the periphery of the pool body into the pool body; the middle water outlet system is used to discharge clean water obtained after the muddy water settles from the middle area of ​​the pool body into the peripheral water outlet system;

[0010] After the muddy water enters the pool body, it settles along the first path or the second path according to its specific gravity, and then the clean water is discharged from the pool body; the first path is that the muddy water flows through the peripheral radial flow area and settles, and the clean water formed is discharged into the peripheral water outlet system; the second path is that the muddy water flows through the peripheral radial flow area and the middle radial flow area in sequence and settles, and the clean water formed is merged into the middle water outlet system, and then discharged into the peripheral water outlet system.

[0011] According to the present invention, the intermediate water outlet system comprises a water collecting tank and an intermediate water outlet pipe;

[0012] The water collecting tank is located in the middle area of ​​the pool body, one end of the middle water outlet pipe is connected to the inner cavity of the water collecting tank, and the other end is connected to the peripheral water outlet system;

[0013] The second approach is that muddy water flows through the peripheral radial flow area and the middle radial flow area in sequence and settles, and the formed clean water flows into the water collecting tank and then is discharged into the peripheral water outlet system through the middle water outlet pipe.

[0014] According to the present invention, a lifting pump is arranged on the middle water outlet pipe.

[0015] According to the present invention, the intermediate water outlet system further comprises an intermediate water collecting tank, the upper portion of which is open, and the intermediate water collecting tank is connected to the water inlet of the water collecting tank;

[0016] The formed clean water flows upward through the middle water collecting tank and flows into the water collecting tank.

[0017] According to the present invention, it also includes a precipitation device;

[0018] The sedimentation device is located at the upper part of the middle area of ​​the tank body;

[0019] The intermediate water collection tank is located above the sedimentation device;

[0020] The second approach is that the muddy water flows through the peripheral radial flow area and the middle radial flow area in sequence for sedimentation and then flows upward through the sedimentation device for further sedimentation. The formed clean water flows upward, is collected through the middle water collecting trough and merges into the water collecting tank, and then is discharged into the peripheral water outlet system through the middle water outlet pipe.

[0021] According to the present invention, an annular intermediate rectifying plate is arranged around the outer periphery of the precipitation device;

[0022] The middle rectifying plate is used to separate the water flow in the peripheral radial flow area from the water flow in the middle radial flow area.

[0023] According to the present invention, it also includes a fixed support system;

[0024] The fixed support system includes a central column, a plurality of trusses and beams;

[0025] The central column is arranged at the center of the tank body;

[0026] One end of each of the trusses is fixed to the periphery of the pool body, and the other end is fixed to the central column;

[0027] The water collecting box, the intermediate water collecting tank and the sedimentation device are all installed on the beam frame, and the beam frame is hoisted on a plurality of the trusses.

[0028] According to the present invention, the sedimentation device comprises a first sedimentation part and a second sedimentation part;

[0029] The first sedimentation part and the second sedimentation part are symmetrically arranged on both sides of the central column, and both include a plurality of inclined plates or inclined tubes arranged at intervals along the radial direction of the pool body. The upper ends of the inclined plates or inclined tubes are away from the central column relative to the lower ends, and the water collecting tank is inserted between the first sedimentation part and the second sedimentation part.

[0030] According to the present invention, the number of the water collecting tank, the intermediate water collecting tank and the intermediate water outlet pipe is set to two;

[0031] The two water collecting tanks are symmetrically arranged on both sides of the central column;

[0032] The two intermediate water collecting troughs are symmetrically arranged on both sides of the two water collecting boxes; each of the intermediate water collecting troughs is an arc-shaped trough body with an open upper end, and the two ends of each intermediate water collecting trough are connected to the water inlets of the two water collecting boxes in a one-to-one correspondence;

[0033] One end of the two intermediate water outlet pipes is connected to the inner cavities of the two water collecting tanks in a one-to-one correspondence, and the other end is connected to the peripheral water outlet system.

[0034] (III) Beneficial effects

[0035] The beneficial effects of the present invention are as follows: the radial flow type circumferential inlet and outlet secondary sedimentation tank with additional intermediate outlet can promote the muddy water with a relatively light specific gravity to flow from the peripheral radial flow area to the intermediate radial flow area for sedimentation by setting up the intermediate outlet system, and discharge the clear water formed by the sedimentation into the intermediate outlet system, so as to avoid the muddy water from meeting and returning with the muddy water on the opposite side when flowing to the center of the tank body, and make full use of the intermediate radial flow area of ​​the tank body for sedimentation, so as to extend the flow path of the muddy water with a relatively light specific gravity, promote the muddy water to fully precipitate, increase the water output per unit area of ​​the secondary sedimentation tank, and improve the effective utilization area of ​​the tank body and the water quality after sedimentation. At the same time, the intermediate outlet system located in the center of the tank body can also alleviate the interference of external wind and effectively reduce the influence of waves on the flow of muddy water. Therefore, the diameter of the tank body can be expanded to 60m to expand the muddy water capacity and improve the muddy water sedimentation efficiency. Furthermore, by using the peripheral outlet system and the intermediate outlet system to discharge water at the same time, the surface load of the secondary sedimentation tank can be increased, and the water output of the secondary sedimentation tank can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a top view schematic diagram of a radial flow type peripheral inlet and outlet secondary sedimentation tank with additional middle water outlet of the present invention;

[0037] Figure 2 for Figure 1 Schematic diagram of the cross section at AA;

[0038] Figure 3 for Figure 1 Schematic diagram of the cross-section at BB.

[0039] [Description of Reference Numerals]

[0040] 1: Pool body;

[0041] 2: Peripheral water distribution system; 21: Peripheral water distribution channel; 211: Water distribution hole; 22: Peripheral water inlet pipe; 23: Rectification baffle;

[0042] 3: Peripheral water outlet system; 31: Peripheral water collection tank; 32: Peripheral water outlet channel; 33: Peripheral water outlet pipe; 34: Peripheral water outlet weir;

[0043] 4: Intermediate water outlet system; 41: water collecting tank; 42: intermediate water collecting tank; 43: intermediate water outlet pipe; 44: lifting pump; 45: intermediate rectifier plate;

[0044] 5: sedimentation device; 51: first sedimentation part; 52: second sedimentation part;

[0045] 6: Fixed support system; 61: Center column; 62: Truss; 63: Beam frame;

[0046] 7: Bottom mud discharge system; 71: Bottom plate; 72: Mud scraper; 73: Central transmission device; 731: Motor; 732: Rotating shaft; 74: Mud hopper; 75: Mud discharge pipe;

[0047] C: peripheral radial flow zone; D: intermediate radial flow zone. DETAILED DESCRIPTION

[0048] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Figure 2 and Figure 3 The orientation is used as a reference.

[0049] See also Figure 1-3 The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet proposed in an embodiment of the present invention includes a tank body 1, a peripheral water distribution system 2, a peripheral water outlet system 3 and an intermediate water outlet system 4.

[0050] The inner cavity of the tank body 1 includes a peripheral radial flow area C and an intermediate radial flow area D. The peripheral water distribution system 2 is used to introduce muddy water from the periphery of the tank body 1 into the tank body 1. The peripheral water outlet system 3 is used to discharge the clean water obtained after the muddy water is precipitated from the tank body 1 from the periphery of the tank body 1. The intermediate water outlet system 4 is used to discharge the clean water obtained after the muddy water is precipitated from the middle area of ​​the tank body 1 into the peripheral water outlet system 3.

[0051] After the muddy water enters the tank body 1, it settles along the first path or the second path according to its specific gravity, and then the clean water is discharged from the tank body 1. The first path is that the muddy water flows through the peripheral radial flow area C and settles, and the clean water formed is discharged into the peripheral water outlet system 3. The second path is that the muddy water flows through the peripheral radial flow area C and the middle radial flow area D in sequence and settles, and the clean water formed is merged into the middle water outlet system 4, and then discharged into the peripheral water outlet system 3.

[0052] It should be noted that the muddy water entering the tank body 1 includes muddy water with a heavier specific gravity and muddy water with a lighter specific gravity. The sludge in the muddy water with a heavier specific gravity is heavier and can be quickly precipitated in the peripheral radial flow area C. The clean water formed by the precipitation of this part of the muddy water can be quickly discharged upward into the peripheral water outlet system 3, while the sludge in the muddy water with a lighter specific gravity is lighter. After flowing through the peripheral radial flow area C for precipitation, it has not yet completely precipitated and needs to continue to flow and precipitate toward the middle radial flow area D. The clean water formed by the precipitation of this part of the muddy water is discharged upward into the middle water outlet system 4. Therefore, the muddy water with a heavier specific gravity precipitates along the first path, and the muddy water with a lighter specific gravity precipitates along the second path. Among them, when the muddy water flows, the sludge in the muddy water can settle to the bottom of the tank body 1, and the clean water formed flows upward.

[0053] The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate outlet is provided with an intermediate outlet system 4, which can promote the muddy water with a relatively light specific gravity to flow from the peripheral radial flow area C to the intermediate radial flow area D for sedimentation and discharge the clear water formed by the sedimentation into the intermediate outlet system 4, so as to avoid the muddy water from meeting and returning with the muddy water on the opposite side when flowing to the center of the tank body 1, and make full use of the intermediate radial flow area D of the tank body 1 for sedimentation, so as to extend the flow path of the muddy water with a relatively light specific gravity, promote the muddy water to fully precipitate, increase the water output per unit area of ​​the secondary sedimentation tank, and improve the effective utilization area of ​​the tank body 1 and the water quality after sedimentation. At the same time, the intermediate outlet system 4 located in the center of the tank body 1 can also alleviate the interference of external wind and effectively reduce the influence of waves on the flow of muddy water. Therefore, the diameter of the tank body 1 can be expanded to 60m to expand the muddy water capacity and improve the muddy water sedimentation efficiency. Furthermore, by using the peripheral outlet system 3 and the intermediate outlet system 4 to discharge water at the same time, the surface load of the secondary sedimentation tank can be increased and the water output of the secondary sedimentation tank can be increased.

[0054] Furthermore, the intermediate water outlet system 4 includes a water collecting tank 41 and an intermediate water outlet pipe 43 .

[0055] The water collecting tank 41 is located in the middle area of ​​the pool body 1 . One end of the middle water outlet pipe 43 is connected to the inner cavity of the water collecting tank 41 , and the other end is connected to the peripheral water outlet system 3 .

[0056] The second way is that the muddy water flows through the peripheral radial flow area C and the middle radial flow area D in sequence and settles, and the clean water formed is collected in the water collecting tank 41 and then discharged into the peripheral water outlet system 3 through the middle water outlet pipe 43.

[0057] Furthermore, a lifting pump 44 is provided on the middle water outlet pipe 43 , and the lifting pump 44 is used to lift the clean water in the water collecting tank 41 upward through the middle water outlet pipe 43 and discharge it into the peripheral water outlet system 3 .

[0058] When in use, the flow rate of the lifting pump 44 can be adjusted according to the inlet flow rate and the effluent water quality of the secondary sedimentation tank, that is, the water output of the intermediate water outlet system 4 is adjusted by controlling the flow rate of the lifting pump 44.

[0059] Furthermore, the intermediate water outlet system 4 further includes an intermediate water collecting tank 42 , the upper portion of which is open, and the intermediate water collecting tank 42 is connected to the water inlet of the water collecting tank 41 .

[0060] In the second path, the clean water flows upward, is collected by the middle water collecting tank 42 and then flows into the water collecting tank 41 , so that the clean water flows into the water collecting tank 41 smoothly.

[0061] Specifically, the middle water collecting tank 42 is located at one side of the water collecting tank 41 .

[0062] Preferably, the middle water collecting tank 42 is made of stainless steel to ensure the strength of use.

[0063] Specifically, the middle water collecting trough 42 is a trough body with an open upper end, and a sawtooth-shaped water outlet weir is arranged at the upper end of the middle water collecting trough 42 to ensure the uniformity and stability of water inflow into the middle water collecting trough 42 .

[0064] Furthermore, the radial flow type circumferential inlet and outlet secondary sedimentation tank with intermediate water outlet also includes a sedimentation device 5.

[0065] The sedimentation device 5 is located at the upper part of the middle area of ​​the tank body 1. The middle water collecting tank 42 is located above the sedimentation device 5.

[0066] The second way is that the muddy water flows through the peripheral radial flow area C and the middle radial flow area D in turn for sedimentation and then flows upward through the sedimentation device 5 for further sedimentation. The formed clean water flows upward, is collected by the middle water collecting trough 42, and then flows into the water collecting tank 41, and then is discharged into the peripheral water outlet system 3 through the middle water outlet pipe 43.

[0067] The sedimentation device 5 can improve the sedimentation effect of muddy water, thereby improving the water quality after sedimentation. The flow rate of the lifting pump 44 is adjusted according to the inlet flow rate and outlet water quality of the secondary sedimentation tank, and the surface load of the sedimentation device 5 is adjusted.

[0068] Furthermore, an annular intermediate rectifying plate 45 is disposed around the outer periphery of the precipitation device 5 .

[0069] The middle rectifying plate 45 is used to separate the water flow in the peripheral radial flow area C from the water flow in the middle radial flow area D, so that the peripheral radial flow area C and the middle radial flow area D of the secondary sedimentation tank form their own independent flow states, avoiding short flow or mixed flow that affects the sedimentation quality of muddy water.

[0070] Furthermore, the radial flow type peripheral inlet and outlet secondary sedimentation tank with a middle water outlet also includes a fixed support system 6.

[0071] The fixed support system 6 includes a central column 61 , a plurality of trusses 62 and a beam frame 63 .

[0072] The central column 61 is arranged at the center of the tank body 1. One end of each truss 62 is fixed to the periphery of the tank body 1, and the other end is fixed to the central column 61. The water collecting tank 41, the intermediate water collecting tank 42, the sedimentation device 5 and the intermediate rectifying plate 45 are all installed on the beam frame 63, and the beam frame 63 is hoisted on multiple trusses 62 to ensure the stability of the intermediate water outlet system 4 and the sedimentation device 5.

[0073] Optionally, the trusses 62 may be constructed in conjunction with the walkway deck of the secondary settling tank.

[0074] Preferably, the truss 62 is made of steel to ensure support stability.

[0075] Specifically, the middle water outlet pipe 43 is installed on the truss 62 .

[0076] Preferably, the sedimentation device 5 includes a first sedimentation portion 51 and a second sedimentation portion 52 .

[0077] The first sedimentation part 51 and the second sedimentation part 52 are symmetrically arranged on both sides of the central column 61, and both include a plurality of inclined plates or inclined tubes arranged at intervals along the radial direction of the pool body 1, and the upper ends of the inclined plates or inclined tubes are away from the central column 61 relative to the lower ends. A space is formed between the first sedimentation part 51 and the second sedimentation part 52, and the space is used to insert the water collecting tank 41, so that the sedimentation device 5 and the water collecting tank 41 are integrated into one, reducing the overall volume, and can increase the setting volume of the water collecting tank 41 within the limited space in the pool body 1, thereby increasing the water capacity of the water collecting tank 41 and accelerating the drainage efficiency. At the same time, the symmetrical arrangement of the first sedimentation part 51 and the second sedimentation part 52 can make the first sedimentation part 51 and the second sedimentation part 52 process the same amount of water, so as to ensure the sedimentation quality of the muddy water on both sides of the pool body 1 and the uniformity of the processed water volume.

[0078] In the second path, the muddy water flows through the peripheral radial flow area C and the middle radial flow area D in turn for sedimentation and then flows upward through the sedimentation channel of the inclined plate or inclined tube for further sedimentation. The precipitated sludge falls to the bottom of the tank body 1 along the side wall of the inclined plate or inclined tube, and the formed clean water flows upward.

[0079] Preferably, the number of the water collecting tank 41, the intermediate water collecting tank 42 and the intermediate water outlet pipe 43 is set to two.

[0080] The two water collecting tanks 41 are symmetrically arranged on both sides of the central column 61. The two intermediate water collecting tanks 42 are symmetrically arranged on both sides of the two water collecting tanks 41. Each intermediate water collecting tank 42 is an arc-shaped tank body with an open upper end, and both ends of each intermediate water collecting tank 42 are connected to the water inlets of the two water collecting tanks 41 in a one-to-one correspondence. One end of the two intermediate water outlet pipes 43 is connected to the inner cavity of the two water collecting tanks 41 in a one-to-one correspondence, and the other end is connected to the peripheral water outlet system 3.

[0081] By providing two water collecting tanks 41 , the water capacity of the water collecting tank 41 is further expanded, and the drainage efficiency to the surrounding water outlet system 3 is accelerated.

[0082] Furthermore, the peripheral water distribution system 2 includes a peripheral water distribution channel 21 , a peripheral water inlet pipe 22 and a rectifying baffle 23 .

[0083] The peripheral water distribution channel 21 is arranged on the inner peripheral wall of the pool body 1, and a plurality of water distribution holes 211 arranged in an annular space are provided at the bottom of the peripheral water distribution channel 21. The peripheral water inlet pipe 22 passes through the peripheral wall of the pool body 1 and is connected to the peripheral water distribution channel 21. The rectifying baffle 23 is arranged at the bottom of the peripheral water distribution channel 21, and the rectifying baffle 23 is annular, and the plurality of water distribution holes 211 are located between the inner peripheral wall of the pool body 1 and the rectifying baffle 23.

[0084] The muddy water enters the peripheral water distribution channel 21 through the peripheral water inlet pipe 22 and is then introduced downward into the pool body 1 through a plurality of water distribution holes 211 .

[0085] By providing a plurality of water distribution holes 211 arranged at intervals in an annular manner, water can be evenly distributed into the tank body 1. By providing a rectifying baffle 23, muddy water flowing down from the water distribution holes 211 can be evenly introduced downward into the mud layer at the bottom of the tank body 1, preventing the muddy water flowing down from the water distribution holes 211 from short-circuiting and affecting the sedimentation effect.

[0086] Furthermore, the peripheral water outlet system 3 includes a peripheral water collecting tank 31 , a peripheral water outlet channel 32 and a peripheral water outlet pipe 33 .

[0087] The peripheral water collecting tank 31 is arranged on the inner peripheral wall of the peripheral water distribution channel 21, and a water outlet hole is provided at the bottom of the peripheral water collecting tank 31. The peripheral outlet channel 32 is arranged below the peripheral water collecting tank 31 and connected to the water outlet hole. The peripheral outlet pipe 33 passes through the peripheral wall of the pool body 1 and is connected to the peripheral outlet channel 32. The intermediate water outlet system 4 is connected to the peripheral outlet pipe 33.

[0088] The first way is that after the muddy water flows through the peripheral radial flow area C and settles, the clean water formed flows into the peripheral water collection tank 31, then merges into the peripheral water outlet channel 32, and is discharged from the pool body 1 through the peripheral water outlet pipe 33.

[0089] The second way is that the muddy water flows through the peripheral radial flow area C and the middle radial flow area D in sequence and settles, and the formed clean water flows into the middle water outlet system 4 and then is discharged from the pool body 1 through the peripheral water outlet pipe 33.

[0090] Specifically, the peripheral water collecting tank 31 is a tank body with an open upper end, and a peripheral water collecting weir 34 is arranged at the upper end of the peripheral water collecting tank 31. Clean water rises and flows into the peripheral water collecting tank 31 through the peripheral water collecting weir 34. The peripheral water collecting weir 34 adopts a sawtooth structure to ensure uniformity and stability of water entering the peripheral water collecting tank 31.

[0091] Specifically, the other ends of the two middle water outlet pipes 43 are connected to the peripheral water outlet pipes 33 .

[0092] Furthermore, the radial flow type peripheral inlet and outlet secondary sedimentation tank with intermediate water outlet also includes a bottom mud discharge system 7.

[0093] The bottom mud discharge system 7 includes a bottom plate 71 of the tank body 1 , a mud scraper 72 , a central transmission device 73 , a mud hopper 74 and a mud discharge pipe 75 .

[0094] The bottom plate 71 is in a downward convex cone shape, and the slope of the bottom plate 71 is 10% to 15%. The sludge precipitated by the muddy water can fall onto the bottom plate 71. The center of the bottom plate 71 is convex downward to form a conical sludge bucket 74. The central transmission device 73 is arranged on the central column 61, and the central transmission device 73 drives and connects the scraper blade 72, and is used to drive the scraper blade 72 to rotate around the central column 61. The mud discharge pipe 75 is connected to the sludge bucket 74.

[0095] When the scraper blade 72 rotates around the central column 61, the scraper blade 72 can squeeze the sludge that falls on the bottom plate 71 to discharge the moisture in the sludge, and the sludge can slide along the downward convex conical bottom plate 71 into the sludge hopper 74 under the action of its own weight, and be discharged from the pool body 1 through the sludge discharge pipe 75.

[0096] Therefore, under the cooperation of the scraper plate 72 and the downward convex conical bottom plate 71, a conical sludge concentration area can be formed. Under the water pressure and the pushing and squeezing of the scraper plate 72, it has a better sludge concentration effect, and can reduce the moisture content of the sludge falling into the sludge hopper 74 to 98%~99%. While ensuring that the amount of recirculating microorganisms remains unchanged, the volume of discharged sludge can be reduced by 20%~30%, so that the energy consumption of the subsequent sludge return system and sludge dewatering system in the sludge is reduced by 20%~30%, and the drug consumption of the sludge dewatering system is saved by 20%~30%, so as to greatly reduce the sludge treatment cost.

[0097] Furthermore, the motor 731 of the central transmission device 73 is arranged on the central column 61, and the rotating shaft 732 of the central transmission device 73 is rotatably connected to the central column 61 through a bearing. The motor 731 drives the rotating shaft 732, and the scraper blade 72 is fixed on the rotating shaft 732. The scraper blade 72 is driven by the motor 731 to rotate around the central column 61.

[0098] Furthermore, the following is a comparison of the size setting and muddy water treatment effect of the radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet and the existing secondary sedimentation tank:

[0099] Example 1

[0100] This example is a radial flow type secondary sedimentation tank with additional intermediate water outlet:

[0101] A 40,000 m 3 / d-scale sewage treatment plant adopts two radial flow type peripheral inlet and outlet secondary sedimentation tanks with additional intermediate water outlet.

[0102] A1: The plane dimensions of the radial flow type secondary sedimentation tank with central water outlet are set as follows:

[0103] The diameter of the tank body 1 is 30 m, the radius of the sedimentation device 5 is 1 / 2 of the radius of the tank body 1 , and the radius of the sedimentation device 5 is 7.5 m.

[0104] The area of ​​a single pool 1 = 3.14 × 15 × 15 = 706.5 m 2 .

[0105] The area of ​​the sedimentation device 5 is 3.14×7.5×7.5=176.63m 2 .

[0106] The area of ​​the peripheral radial flow zone C = 706.5-176.63 = 529.87m 2 .

[0107] The ratio of the flow rate of the middle radial flow area D to the flow rate of the surrounding radial flow area C is 2 / 3, that is, the flow rate of the middle radial flow area D is 8000m 3 / d, the flow rate of the surrounding radial flow area C is 12000m 3 / d.

[0108] Then the actual surface load of the middle radial flow area D = flow rate / area of ​​the inclined pipe area = 8000 / 24 / 176.63 = 1.89m 3 / (m 2 h).

[0109] The actual surface load of the peripheral radial flow area C = flow rate / area = 1200÷24÷529.87=0.94m 3 / (m 2 h).

[0110] Average surface load of the secondary sedimentation tank = 0.94 × 529.87 + 1.89 × 176.63 ÷ 706.5 = 1.18m 3 / (m 2 h)

[0111] A2: Verification of solid flux of the biochemical pool used to discharge sewage into the secondary sedimentation tank:

[0112] The design suspended solids concentration of the biochemical pool is 40g / L, i.e. 4.0kg / m 3 .

[0113] Solid flux = suspended solid concentration × flow rate / secondary sedimentation tank area = 4.0 × 20000 ÷ 706.5

[0114] =113.23kg / (m 2 ·d).

[0115] Considering that the sludge return ratio is 0.75, the solid flux at this time is 113.23×(1+0.75)=198.15kg / (m 2 ·d).

[0116] A3: Design water depth, pool depth design

[0117] The inclined tube in the sedimentation device 5 is 1m long, 100mm in diameter, 60° in angle, and 0.87m in height. The water depth of the upper clear water area of ​​the inclined tube is 0.93m, and the height of the lower buffer layer of the inclined tube is 1.2m. Below the buffer layer is the sludge area.

[0118] The water depth around the secondary sedimentation tank is 5.0m, of which the water depth in the upper sedimentation area is 3.0m, the water depth in the lower sludge area is 2.0, the super height of the secondary sedimentation tank is 0.3m, and the total height around the sedimentation tank is 5.0m.

[0119] The sedimentation time of the secondary sedimentation tank = the peripheral depth of the secondary sedimentation tank / average surface load = 5÷1.18=4.24h.

[0120] The diameter-to-depth ratio of the secondary sedimentation tank = 30÷5=6.

[0121] A4: Design of cone-shaped sludge thickening area at the bottom of the secondary sedimentation tank:

[0122] The slope of the bottom plate 71 is 10%, the height difference between the center and the periphery of the bottom plate 71 is 1.3m, the upper radius of the sludge hopper 74 is 2m, the lower radius is 1m, the depth of the sludge hopper 74 is 0.8m, and the volume of the sludge concentration area is 346.55m 3 , the sludge moisture content is 98.2%.

[0123] The design flow rate of a single secondary sedimentation tank is Q = 20000m 3 / d, the suspended solid concentration in mud water is 40g / L.

[0124] Since the modified secondary sedimentation tank has the function of sludge concentration, the water content of the discharged sludge is about 1% lower than that of the traditional secondary sedimentation tank. Under the condition of the same microbial biomass returned to the biochemical pool, the sludge return ratio can be reduced from the traditional 50% to 100% to 50% to 75%.

[0125] Example 2

[0126] This example is an existing secondary sedimentation tank:

[0127] Two traditional circumferential inlet and outlet secondary sedimentation tanks are used, and the design flow rate of each secondary sedimentation tank is 20,000m 3 / d, the suspended solid concentration in the biochemical pool is 40g / L, and the sludge return ratio is 50% to 100%.

[0128] B1. Plane size design

[0129] The diameter of the secondary sedimentation tank is 36m. The area of ​​a single secondary sedimentation tank = 3.14 × 18 × 18 = 1017.36m 2 .

[0130] Actual surface load = 20000 ÷ 24 ÷ 1017.36 = 0.819 m 3 / (m 2 h).

[0131] B2. Solid flux review:

[0132] The design suspended solids concentration of the biochemical pool is 40g / L, i.e. 4.0kg / m3 .

[0133] Solid flux = suspended solid concentration × flow rate ÷ area = 4 × 20000 ÷ 1017.36 =

[0134] 78.60kg / (m 2 ·d).

[0135] Solid flux is verified based on 100% sludge return ratio: 78.60×2=157.20kg / (m 2 d)

[0136] B3. Design water depth and pool depth design

[0137] The diameter-to-depth ratio of the secondary sedimentation tank is 9, the water depth around it is 4.0m, and the sedimentation time is 4.88h. The water depth of the upper sedimentation area is 2.0m, and the water depth of the lower sludge area is 2.0m. The super height of the secondary sedimentation tank is 0.5m, and the total height around the sedimentation tank is 4.5m.

[0138] The slope of the bottom plate 71 of the sedimentation tank is 0.5%, and the height difference between the center and the periphery of the bottom plate 71 is 0.09 m. Since the secondary sedimentation tank does not have a sludge concentration zone, the water content of the sludge discharged from the secondary sedimentation tank is 99.2%.

[0139] From the above, it can be seen that Example 1 has a secondary sedimentation tank diameter 6m smaller than Example 2, the land area is reduced by 30.5%, and the sludge moisture content is reduced by about 1%, which has obvious advantages.

[0140] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0141] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0142] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0143] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0144] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A radial flow type peripheral inlet and outlet secondary sedimentation tank with an additional intermediate outlet, comprising a tank body (1), a peripheral water distribution system (2), and a peripheral outlet system (3), characterized in that: Also includes an intermediate water outlet system (4); The inner cavity of the cell body (1) comprises a peripheral radial flow area (C) and a middle radial flow area (D); The peripheral water distribution system (2) is used to introduce muddy water from the periphery of the tank body (1) into the tank body (1); the peripheral water outlet system (3) is used to discharge clean water obtained after the muddy water is precipitated from the periphery of the tank body (1) out of the tank body (1); the middle water outlet system (4) is used to discharge clean water obtained after the muddy water is precipitated from the middle area of ​​the tank body (1) into the peripheral water outlet system (3); After the muddy water enters the pool body (1), it settles along the first path or the second path according to its specific gravity, and then the clean water is discharged from the pool body (1); the first path is that the muddy water flows through the peripheral radial flow area (C) and settles, and the clean water formed is discharged into the peripheral water outlet system (3); the second path is that the muddy water flows through the peripheral radial flow area (C) and the intermediate radial flow area (D) in sequence and settles, and the clean water formed is merged into the intermediate water outlet system (4), and then discharged into the peripheral water outlet system (3); The intermediate water outlet system (4) comprises a water collecting tank (41) and an intermediate water outlet pipe (43); The water collecting tank (41) is located in the middle area of ​​the pool body (1); one end of the middle water outlet pipe (43) is connected to the inner cavity of the water collecting tank (41), and the other end is connected to the peripheral water outlet system (3); The second pathway is that the muddy water flows through the peripheral radial flow area (C) and the middle radial flow area (D) in sequence and settles, and the clean water formed flows into the water collecting tank (41), and then is discharged into the peripheral water outlet system (3) through the middle water outlet pipe (43); The intermediate water outlet system (4) further comprises an intermediate water collecting tank (42), the upper portion of the intermediate water collecting tank (42) being open, and the intermediate water collecting tank (42) being connected to the water inlet of the water collecting tank (41); The formed clean water flows upward through the middle water collecting tank (42) and flows into the water collecting tank (41); It also includes a precipitation device (5); The sedimentation device (5) is located at the upper part of the middle area of ​​the tank body (1) of the tank body (1); The intermediate water collecting tank (42) is located above the sedimentation device (5); The second pathway is that the muddy water flows through the peripheral radial flow area (C) and the intermediate radial flow area (D) in sequence for sedimentation and then flows upward through the sedimentation device (5) for further sedimentation. The formed clean water flows upward, is collected through the intermediate water collecting trough (42), and flows into the water collecting tank (41), and then is discharged into the peripheral water outlet system (3) through the intermediate water outlet pipe (43).

2. The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet as claimed in claim 1, characterized in that: A lifting pump (44) is provided on the middle water outlet pipe (43).

3. The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet as claimed in claim 1, characterized in that: An annular intermediate rectifying plate (45) is arranged around the outer periphery of the precipitation device (5); The intermediate rectifying plate (45) is used to separate the water flow in the peripheral radial flow area (C) from the water flow in the intermediate radial flow area (D).

4. The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet as claimed in claim 1, characterized in that: Also included is a fixed support system (6); The fixed support system (6) comprises a central column (61), a plurality of trusses (62) and a beam frame (63); The central column (61) is arranged at the center of the tank body (1); One end of each of the trusses (62) is fixed to the periphery of the pool body (1), and the other end is fixed to the central column (61); The water collecting box (41), the intermediate water collecting tank (42) and the sedimentation device (5) are all installed on the beam frame (63), and the beam frame (63) is hoisted on the plurality of trusses (62).

5. The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet as claimed in claim 4, characterized in that: The sedimentation device (5) comprises a first sedimentation portion (51) and a second sedimentation portion (52); The first sedimentation portion (51) and the second sedimentation portion (52) are symmetrically arranged on both sides of the central column (61), and both include a plurality of inclined plates or inclined tubes arranged at intervals along the radial direction of the pool body (1), the upper ends of the inclined plates or inclined tubes being farther away from the central column (61) than the lower ends, and the water collecting tank (41) is inserted between the first sedimentation portion (51) and the second sedimentation portion (52).

6. The radial flow type peripheral inlet and outlet secondary sedimentation tank with additional intermediate water outlet as claimed in claim 5, characterized in that: The number of the water collecting box (41), the intermediate water collecting tank (42) and the intermediate water outlet pipe (43) is set to two; The two water collecting tanks (41) are symmetrically arranged on both sides of the central column (61); The two intermediate water collecting grooves (42) are symmetrically arranged on both sides of the two water collecting boxes (41); each of the intermediate water collecting grooves (42) is an arc-shaped groove body with an open upper end, and both ends of each intermediate water collecting groove (42) are connected to the water inlets of the two water collecting boxes (41) in a one-to-one correspondence; One end of the two intermediate water outlet pipes (43) is connected to the inner cavities of the two water collecting tanks (41) in a one-to-one correspondence, and the other end is connected to the peripheral water outlet system (3).

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