Processing tank and processing system

Abstract

To provide a technique capable of installing a heavy stirrer in a treatment tank at a low cost.SOLUTION: The processing tank includes a tank main body that includes a ceiling portion in which an opening portion is formed and that stores a processing target object, a stirrer that includes a stirring unit that is disposed inside the tank main body and that stirs the processing target object and an exposed portion that is exposed to an outside of the tank main body through the opening portion, and a stand that supports the stirrer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a treatment vessel and a treatment system. [Background technology]

[0002] As a tank for treating materials to be treated (e.g., organic matter contained in primary sludge and excess sludge), a treatment tank equipped with an agitator that agitates the materials to be treated in the tank to promote treatment is known. This agitator has, for example, an impeller located inside the tank body (frame) and a motor located outside the tank body for rotating the impeller, and is installed in a state where it penetrates the ceiling of the tank body. In relation to this, a technology has been proposed in which the agitator is supported by a center dome provided on the top of the tank body (see Patent Document 1) and a technology in which the agitator is supported by a gate-shaped frame installed on the ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-142288 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when installing an agitator in a center dome, as in Patent Document 1, for example, the load conditions become strict, which imposes weight restrictions on the agitator that can be installed, and as a result, there is a risk that a heavy agitator cannot be installed.

[0005] Therefore, an object of the present disclosure is to provide a technology that enables a heavy agitator to be installed in a treatment tank at low cost. [Means for solving the problem]

[0006] The treatment tank according to the present disclosure comprises a tank body having a ceiling portion with an opening formed therein and for storing the material to be treated, an agitator disposed inside the tank body and for agitating the material to be treated, and having an exposed portion exposed to the outside of the tank body through the opening, and a stand for supporting the agitator, the stand having a fixing portion to which the exposed portion is fixed and a base portion installed on the upper surface of the ceiling portion so as to surround the opening. [Effects of the Invention]

[0007] The treatment tank of the present disclosure makes it possible to install a heavy agitator at low cost. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a processing system 1000 according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the configuration of a digestion tank 60 according to an embodiment. [Figure 3] FIG. 3 is a top view of the digester 60 according to the embodiment. [Figure 4] FIG. 4 is a partially enlarged view of the digestion tank 60 according to the embodiment. [Figure 5] FIG. 5 is a flow chart illustrating a method for installing the agitator 2 in the embodiment. [Figure 6] FIG. 6 is a top view showing gantry bodies 4A to 4C according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, such descriptions should not be interpreted in a limiting sense, and do not limit the subject matter described in the claims. Furthermore, various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure. Furthermore, different embodiments can be combined as appropriate.

[0010] The following describes an embodiment in which the technology of the present disclosure is applied to a digester tank, which is an example of a sewage treatment tank. The technology of the present disclosure can be applied to sewage treatment tanks, such as digester tanks that treat sludge by biological treatment and reaction tanks that treat organic wastewater by biological treatment. However, the application of the technology of the present disclosure is not limited to sewage treatment tanks. The treatment tank to which the present disclosure is applied may be, for example, a tank that treats materials stored in the tank body while stirring with an agitator, and the treatment method and materials are not particularly limited.

[0011] [Processing system 1000] First, a processing system 1000 according to the embodiment will be described. Fig. 1 is a diagram illustrating the configuration of the processing system 1000 according to the embodiment.

[0012] The treatment system 1000 in this embodiment is, for example, a water treatment system that treats liquid such as sewage (hereinafter also referred to as water to be treated).

[0013] 1, the treatment system 1000 includes, for example, a primary sedimentation tank 10, a tank 20 (hereinafter also referred to as a reaction tank 20), a final sedimentation tank 30, a thickening device 40, a thickening device 50, a tank 60 (hereinafter also referred to as a digestion tank 60), a temperature adjustment system 100, and a control device 200. Note that, hereinafter, the treatment system 1000 will also be referred to as a digestion system 1000.

[0014] The primary sedimentation tank 10 separates, for example, organic and other contaminants (e.g., solid organic matter) contained in the water to be treated. The separated contaminants (hereinafter also referred to as primary sludge) are then discharged to a concentration device 40 by, for example, a pump (not shown). The water to be treated after the separation of contaminants by sedimentation is then discharged to a digestion tank 60 by, for example, a pump (not shown).

[0015] The reaction tank 20 is a tank that treats the water to be treated by biological treatment such as the standard activated sludge method. Specifically, the reaction tank 20 decomposes organic matter (e.g., soluble organic matter) contained in the water to be treated, for example, by microorganisms (hereinafter also referred to as activated sludge) propagated in the reaction tank 20. Then, after the organic matter has been decomposed by the activated sludge, the water to be treated is discharged from the reaction tank 20 to the final sedimentation tank 30 by, for example, overflow.

[0016] The final settling tank 30, for example, separates and discharges activated sludge contained in the water to be treated discharged from the reaction tank 20. Then, a part of the settled and separated activated sludge (hereinafter also referred to as excess sludge) is discharged to the thickening device 50, for example, by a pump (not shown). Another part of the settled and separated activated sludge (hereinafter also referred to as returned sludge) is returned to the reaction tank 20, for example, by a pump (not shown). Furthermore, the water to be treated after the activated sludge separation is discharged to a downstream sterilization treatment device (not shown) by, for example, overflow. Thereafter, the sterilization treatment device sterilizes the water to be treated discharged from the final settling tank 30, for example, and releases the sterilized treated water into a river or the like.

[0017] The thickening device 40 thickens the sludge separated from the water to be treated. More specifically, the thickening device 40 thickens, for example, the primary sludge discharged from the primary sedimentation tank 10. The thickened primary sludge is then discharged into the digestion tank 60 by, for example, a pump (not shown). The liquid separated from the primary sludge by the thickening is returned to the primary sedimentation tank 10 by, for example, a pump (not shown).

[0018] The concentrator 50, for example, concentrates sludge separated from the water to be treated. More specifically, the concentrator 50 concentrates, for example, excess sludge discharged from the final settling tank 30. The concentrated excess sludge is then discharged to the digestion tank 60 by, for example, a pump (not shown). Note that the liquid separated from the excess sludge by the concentration is returned to the final settling tank 30 by, for example, a pump (not shown).

[0019] The digester 60 treats sludge supplied from, for example, the thickener 40 or 50 through biological treatment. More specifically, the digester 60 uses, for example, anaerobic bacteria in the digester 60 to anaerobically digest (decompose) organic matter contained in the primary sludge supplied from the thickener 40 and the excess sludge supplied from the thickener 50 through a biological reaction, producing digested sludge. Specifically, the anaerobic bacteria in the digester 60 produce, for example, digestion gases (hereinafter simply referred to as digestion gases) such as methane gas during the digestion process. Note that the temperature of the digested sludge (digested liquid) in the digester 60 is preferably maintained between 35°C and 39°C, for example, to efficiently promote biological reactions and improve digestion efficiency. The digested sludge discharged from the digester 60 is incinerated, for example, in an incinerator (not shown).

[0020] The temperature adjustment system 100 adjusts the temperature of excess sludge, for example, before it is supplied to the digestion tank 60. Specifically, the temperature adjustment system 100 has, for example, a heater (not shown) and a pump (not shown), and uses the heater to heat the excess sludge before it is supplied to the digestion tank 60, and then supplies the temperature-adjusted excess sludge to the digestion tank 60 using the pump.

[0021] The control device 200 is, for example, a computer device, and controls the adjustment of the temperature of the excess sludge supplied to the digestion tank 60.

[0022] [Digester tank 60] Next, the digestion tank 60 according to this embodiment will be described. Figure 2 is a cross-sectional view illustrating the digestion tank 60 according to this embodiment. Note that the up and down directions indicated by the arrows in Figure 2 represent up and down in the direction of gravity (vertical direction). Figure 2 shows a cross section along the up and down direction. Figure 3 is a top view of the digestion tank 60 according to this embodiment. Figure 4 is a partially enlarged view of the digestion tank 60 according to this embodiment.

[0023] As shown in Fig. 2, the digestion tank 60 in this embodiment includes, for example, a tank body 1 that stores sludge (an example of a material to be treated), an agitator 2 that agitates the sludge, a stand 3 that supports the agitator 2, and a sealing member 6. The digestion tank 60 in this embodiment promotes anaerobic digestion through a biological reaction, for example, by agitating the sludge stored in the tank body 1 with the agitator 2. Note that in this embodiment, the digestion tank 60 is an example of a "treatment tank" in the present disclosure. However, the treatment tank in the present disclosure is not limited to a digestion tank.

[0024] [Tank body 1] The tank body 1 stores, for example, sludge to be supplied to the digestion tank 60. The tank body 1 is, for example, a tank made of concrete. However, the material of the tank body 1 is not particularly limited, and it may be made of, for example, steel.

[0025] As shown in Fig. 2, the tank body 1 has, for example, a generally cylindrical outer shape. Specifically, the tank body 1 has, for example, a generally cylindrical sidewall portion 11 extending in the vertical direction, a ceiling portion 12 closing the upper end of the sidewall portion 11, and a bottom portion 13 closing the lower end of the sidewall portion 11. For example, the tank body 1 is installed with the bottom portion 13 buried in the ground. For example, the sidewall portion 11, the ceiling portion 12, and the bottom portion 13 define an internal space 14 of the tank body 1. For example, sludge is stored (contained) in this internal space 14. Note that the shape of the tank body in the present disclosure is not limited to a cylindrical shape and may be, for example, a box-like or egg-like shape.

[0026] 2, an opening 15 is formed in the ceiling portion 12, for example, to connect the inside (i.e., the internal space 14) of the tank body 1 to the outside. The opening 15 is formed in the center of the ceiling portion 12, for example.

[0027] As shown in FIG. 2, the ceiling portion 12 has, for example, an upper wall portion 121 connected to the side wall portion 11 and a cylindrical protrusion portion 122 protruding upward from the upper wall portion 121.

[0028] The upper wall portion 121 extends, for example, from the upper end of the side wall portion 11 toward the radially inner side of the side wall portion 11. The upper wall portion 121 has, for example, a dome shape that is convex upward, and is curved so as to protrude upward as it moves toward the radially inner side of the side wall portion 11 (i.e., toward the center of the ceiling portion 12). Note that the upper wall portion 121 does not have to be formed in a dome shape, and may, for example, extend horizontally.

[0029] The protrusion 122 is provided, for example, in the center of the upper wall portion 121 and extends upward from the inner end of the upper wall portion 121 in the radial direction of the side wall portion 11. For example, the opening 15 described above is formed by the inner circumferential wall of the protrusion 122. Note that the ceiling portion 12 does not necessarily have to have the protrusion 122.

[0030] [Mixer 2] As shown in FIG. 2, the agitator 2 has, for example, an agitation unit 21 that is arranged inside the tank body 1 (i.e., the internal space 14) and agitates the sludge, and a drive unit 22 that is arranged outside the tank body 1 and drives the agitation unit 21.

[0031] The stirring unit 21 has, for example, a rotating shaft 211 extending in the vertical direction and a stirring blade 212 attached to the rotating shaft 211.

[0032] The rotating shaft 211 is inserted, for example, through an opening 15 formed in the ceiling part 12 of the tank body 1 and is connected to a drive part 22 outside the tank body 1.

[0033] The stirring blade 212 is connected to a rotation shaft 211 inside the tank body 1, for example.

[0034] In the agitator 21, for example, a rotation shaft 211 is rotationally driven by a drive unit 22, and the agitator blades 212 agitate the sludge.

[0035] As shown in FIG. 4, the driving unit 22 includes, for example, a driving shaft 221, a motor 222, and a casing 223.

[0036] The drive shaft 221 extends, for example, in the vertical direction and is connected to the rotation shaft 211 of the agitator 21 outside the tank body 1.

[0037] The motor 222, for example, rotates the drive shaft 221. The motor 222 may be provided with, for example, a reducer.

[0038] The casing 223 is formed, for example, in a substantially cylindrical shape extending in the vertical direction, and houses the rotating shaft 211 and the drive shaft 221 outside the tank body 1. In addition, for example, a step is provided in the radial direction on the outer periphery of the casing 223, thereby forming an annular supported surface 224 facing downward.

[0039] For example, when the motor 222 rotates the drive shaft 221, the rotation of the drive shaft 221 is transmitted to the rotary shaft 211 of the agitator 21. This causes the rotary shaft 211 to rotate, and the agitator blades 212 agitate the sludge.

[0040] 2 and 4, the drive unit 22 is exposed to the outside of the tank body 1 through an opening 15 formed in the ceiling 12. In this embodiment, the drive unit 22 corresponds to an example of the "exposed portion" in the present disclosure. However, the exposed portion in the present disclosure may be, for example, a part of the agitator that is exposed to the outside of the tank body through an opening, and is not limited to the drive unit.

[0041] In this embodiment, as an example, a so-called impeller-type agitator 2 that performs agitation using the agitating blades 212 is used, but the type of agitator in this disclosure is not limited to this. For example, various types of agitators, such as a screw-type agitator, can be used.

[0042] [Mount 3] As shown in FIG. 2, the gantry 3 includes, for example, a gantry main body 4 and a base portion 5.

[0043] [Main unit 4] The gantry main body 4 is installed, for example, on the upper surface of the ceiling portion 12. The gantry main body 4 is made of, for example, metal and is configured to include a plurality of steel members. However, the material of the gantry main body 4 is not particularly limited. As shown in FIGS. 2 and 3 , the gantry main body 4 has, for example, a fixed portion 41 to which the drive unit 22 of the agitator 2 is fixed, a base portion 42 arranged to surround the fixed portion 41, and a beam portion 43 connecting the fixed portion 41 and the base portion 42.

[0044] As shown in FIG. 4, the fixing portion 41 further includes, for example, an annular frame 411 and a support plate 412.

[0045] The annular frame 411 is formed into a ring shape by, for example, bending an H-shaped steel, and is installed directly above the protrusion 122 of the tank body 1 so as to surround the drive unit 22 of the agitator 2. The annular frame 411 includes, for example, a pair of flanges 411a, 411a extending horizontally, and a web 411b extending in the vertical direction and connecting the pair of flanges 411a, 411a to each other.

[0046] The support plate 412 is a plate-like member made of, for example, a steel plate, and is installed horizontally. The support plate 412 is fixed to the upper surface of the annular frame 411 by, for example, welding. As an example, a through-hole 412a is formed in a region of the support plate 412 that is more inward than the annular frame 411, through which the drive unit 22 of the agitator 2 can be inserted.

[0047] For example, the drive unit 22 of the agitator 2 is inserted into the through-hole 412a of the support plate 412. Then, with the supported surface 224 of the drive unit 22 placed on the support plate 412, the drive unit 22 and the support plate 412 are fixed together by fastening members (not shown) such as bolts.

[0048] The base portion 42 is formed into a ring shape by bending an H-shaped steel, for example, and is placed on the ceiling portion 12 (more specifically, the upper wall portion 121) so as to surround the opening 15 of the tank body 1, as shown in Fig. 2. The base portion 42 has a larger diameter than the fixed portion 41, for example, and is positioned further outward than the fixed portion 41, as shown in Fig. 2. In this embodiment, the base portion 42 is positioned lower than the fixed portion 41, for example.

[0049] 4, the base 42 includes, for example, a pair of horizontally extending flanges 42a, 42a and a web 42b that extends in the vertical direction and connects the pair of flanges 42a, 42a. Hereinafter, for convenience, the flange 42a that is located lower of the pair of flanges 42a, 42a may be referred to as the "lower flange 42a."

[0050] The lower flange portion 42a is fixed to the upper wall portion 121 of the ceiling portion 12 by fastening members (not shown) such as bolts, for example, via the base portion 5 described below. In this way, the base portion 42 is installed on the ceiling portion 12.

[0051] In this specification, the term "annular" refers to any shape that surrounds an inner region, and does not necessarily have to be continuous around the entire circumference. It may also have a discontinuous or intermittent shape in the circumferential direction, as in the modified examples described below. The outer shape of the "annular" is not limited to a perfect circle, ellipse, or other circular shape, but may also be a polygonal shape such as a triangle or rectangle, and may have any other shape. While the base portion 42 in this embodiment is formed in a circular ring shape that is continuous around the entire circumference, the shape of the base portion in this disclosure is not limited to this.

[0052] The beam portion 43 is formed of, for example, a steel plate, and is installed at an angle between the fixed portion 41 and the base portion 42 as shown in Fig. 4. In addition, as shown in Fig. 3, for example, a plurality of beam portions 43 are arranged radially around the fixed portion 41, and each beam portion 43 extends along the radial direction of the base portion 42.

[0053] As an example, one end of the beam portion 43 is connected to the fixed portion 41, and the other end is connected to the base portion 42. More specifically, for example, one end of the beam portion 43 is fixed by welding or the like to the inner wall of a groove formed on the outer periphery of the annular frame body 411 by a pair of flange portions 411a, 411a and a web 411b. Furthermore, for example, the other end of the beam portion 43 is fixed by welding or the like to the inner wall of a groove formed on the inner periphery of the base portion 42 by a pair of flange portions 42a, 42a and a web 42b. In this way, the fixed portion 41 and the base portion 42 are connected by the beam portion 43.

[0054] 4, the beam portion 43 is divided, for example, in its extending direction, into an inner beam portion 431 connected to the fixed portion 41 and an outer beam portion 432 connected to the base portion 42. The inner beam portion 431 and the outer beam portion 432 are connected by, for example, a joint member 433.

[0055] [Basic part 5] The foundation 5 is formed, for example, from a cement-based material that is filled without gaps between the ceiling 12 of the tank body 1 and the base 42 of the frame body 4 and solidified, and supports the base 42. Examples of cement-based materials that form the foundation 5 include mortar, concrete, and asphalt. Specifically, in this embodiment, the foundation 5 is formed, for example, from mortar. The foundation 5 is formed, for example, in an annular shape. More specifically, the foundation 5 is formed, for example, in an annular shape that is continuous around the entire circumference so as to follow the base 42.

[0056] [Sealing material 6] The sealing member 6 is, for example, interposed between the ceiling part 12 of the tank body 1 and the fixing part 41 of the pedestal body 4 to seal between the tank body 1 and the pedestal body 4. The sealing member 6 is, for example, a protective tube made of resin, and as shown in FIG. 4, is interposed between the protruding part 122 and the annular frame 411 so as to surround the opening 15. This prevents sludge in the internal space 14 from leaking from the gap between the tank body 1 and the pedestal body 4.

[0057] [About load] Here, for example, the area of ​​the ceiling portion 12 on which the loads of the agitator 2 and the stand 3 act is referred to as the "load area." In FIG. 4, the load area is indicated by the symbol R1. Specifically, the load area R1 is, for example, the area of ​​the ceiling portion 12 on which the base portion 42 is installed. The shape of the load area R1 corresponds to, for example, the shape of the underside of the base portion 42. For example, if the base portion 42 is formed in an annular shape, the load area R1 is also formed in an annular shape along the base portion 42. More specifically, in this embodiment, since the foundation portion 5 is provided between the ceiling portion 12 and the base portion 42, the load area R1 is, for example, the area of ​​the ceiling portion 12 that comes into contact with the foundation portion 5.

[0058] In this embodiment, the weight of the agitator 2 supported by the pedestal 3 acts as a load on the load region R1, in addition to the weight of the pedestal 3 including the pedestal main body 4 and the base 5. Here, as described above, the base 42 is installed so as to surround the opening 15, and therefore the load region R1 is also formed so as to surround the opening 15. As a result, the load of the agitator 2 and the pedestal 3 acts in a dispersed manner on the ceiling 12.

[0059] Here, for example, the total weight of the stand 3 and the agitator 2 is defined as M [N]. The total weight M is, for example, the combined weight of the stand body 4, the base 5, and the agitator 2, and is the load acting on the load region R1.

[0060] 4, for example, the inner diameter of the base portion 42 is L [mm] and the width of the base portion is d [mm]. The inner diameter L is, for example, the distance between the central axis of the base portion 42 and the lower flange portion 42a. The width d is, for example, the width of the H-shaped steel material that constitutes the base portion 42, and more specifically, the width of the lower flange portion 42a in the radial direction of the base portion 42.

[0061] Furthermore, for example, the load per unit area acting on the ceiling portion 12 due to the total weight M is defined as a distributed load P1 [N / mm].

[0062] Also, for example, the allowable distributed load of the ceiling portion 12 is assumed to be P [N / mm]. The allowable distributed load refers to the load per unit area that the structure can support when, for example, the maximum stress intensity generated in the cross section of each member of the structure reaches the allowable stress intensity (limit point). The allowable distributed load P of the ceiling portion 12 can be set, for example, based on the strength and load-bearing capacity of the concrete used in the ceiling portion 12. For example, if the distributed load P1 is less than the allowable distributed load P of the ceiling portion 12, it can be said that the mixer 2 can be installed for a long period of time.

[0063] At this time, the load condition for preventing the distributed load P1 from exceeding the allowable distributed load P can be expressed by, for example, the following formula (A).

number

[0064] Furthermore, if the area of ​​the load region R1 is A, the distributed load P1 can be expressed by, for example, the following formula (B).

number

[0065] Furthermore, the area A of the load region R1 can be approximated by the following formula (C) using the width d, for example.

number

[0066] As can be seen from the above equations (B) and (C), for example, if the width d of the base portion 42 is constant, the area A of the load region R1 increases as the inner diameter L increases, and the distributed load P1 can be reduced.

[0067] At this time, from the formulas (A) and (B), the load condition for preventing the distributed load P1 from exceeding the allowable distributed load P can be expressed, for example, by the following formula (D).

number

[0068] Then, from the formulas (C) and (D), the inner diameter L of the base portion 42 that satisfies the load conditions can be expressed, for example, by the following formula (1).

number

[0069] In this embodiment, for example, the inner diameter L is set so as to satisfy the above formula (1), which makes it possible to prevent the load per unit area acting on the ceiling portion 12 (distributed load P1) from exceeding the allowable distributed load P.

[0070] In this embodiment, the stand 3 may not have the base 5, and the base 42 may be installed directly on the upper surface of the ceiling 12. In that case, the load area R1 is, for example, the area of ​​the ceiling 12 that comes into contact with the base 42, and the total weight M is, for example, the combined weight of the stand main body 4 and the agitator 2.

[0071] [How to install the mixer] A method for installing the agitator 2 using the stand 3 in this embodiment will be described below. Figure 5 is a flowchart illustrating the method for installing the agitator 2 in this embodiment. Note that the following description will be given taking as an example a case where the agitator 2 is installed when a new digestion tank 60 is constructed, but the installation method is not limited to this. The installation method in this embodiment may also be performed, for example, for the purpose of replacing an agitator installed in an existing digestion tank 60.

[0072] In the method of installing the agitator 2, first, for example, in step S1 shown in FIG.

[0073] Specifically, in step S1, for example, the components of the gantry main body 4 are prepared, and first, the base 42 is installed on the ceiling 12 of the tank main body 1. When installing the base 42, the base 42 is placed on the upper surface of the upper wall 121 so as to surround the opening 15, and is fixed with fastening members such as bolts. Next, for example, a cement-based material such as mortar is filled between the ceiling 12 and the base 42 to form the foundation 5. Next, the fixing parts 41 are connected to the base 42 by the beams 43, thereby assembling the gantry main body 4. In this way, the gantry 3 is installed on the tank main body 1.

[0074] After step S1, for example, in step S2 shown in FIG.

[0075] Specifically, in step S2, for example, the agitator 2 is fixed to the fixing portion 41 of the stand 3 so that the agitator 21 is disposed in the internal space 14 of the tank body 1 and the drive unit 22 is disposed outside the tank body 1. More specifically, for example, the supported surface 224 of the drive unit 22 is placed on and fixed to the support plate 412 of the fixing portion 41, and the rotation shaft 211 of the agitator 21 and the drive shaft 221 of the drive unit 22 are connected. In this way, the agitator 2 is fixed to the stand 3. Also, in step S2, for example, a seal member 6 is installed between the ceiling portion 12 (specifically, the protrusion 122) and the fixing portion 41 (specifically, the annular frame 411).

[0076] In this manner, the agitator 2 is installed in the tank body 1 of the digestion tank 60.

[0077] [Actions and Effects] As described above, the digester tank 60 in this embodiment includes, for example, a tank body 1 having a ceiling portion 12 with an opening 15 formed therein and storing sludge (an example of a material to be treated), an agitator 2 disposed inside the tank body 1 and having an agitator 21 for agitating the sludge and a drive unit 22 (an example of an exposed unit) exposed to the outside of the tank body 1 through the opening 15, and a base 3 for supporting the agitator 2. The base 3 also includes, for example, a fixing portion 41 to which the drive unit 22 is fixed and a base portion 42 installed on the upper surface of the ceiling portion 12 so as to surround the opening 15.

[0078] According to this embodiment, for example, the base 42 is installed so as to surround the opening 15, so that the load of the agitator 2 and the pedestal 3 acts in a dispersed manner on the ceiling 12. This prevents the load of the agitator 2 and the pedestal 3 from acting locally, allowing the ceiling 12 to support the load of the agitator 2 and the pedestal 3. This relaxes the load conditions, making it possible to install a heavy agitator 2 on the ceiling 12. Ultimately, it becomes possible to mount a high-performance agitator 2 in the digestion tank 60. Furthermore, according to this embodiment, for example, the agitator 2 is supported by the pedestal 3 installed on the ceiling 12, so there is no need to increase the size of the pedestal, such as a portal-type pedestal. As a result, according to this embodiment, a heavy agitator 2 can be installed at low cost.

[0079] Here, for example, the side wall 11 of the tank body 1 tends to have a greater bearing capacity against a vertical load than the ceiling 12. Therefore, from the viewpoint of installing a heavy agitator 2, it is preferable that the ceiling 12 bears the load at a position closer to the side wall 11. In other words, it is preferable that the load region R1 is closer to the side wall 11. In this embodiment, for example, the load condition can be alleviated by moving the base 42 away from the vicinity of the opening 15 and installing it at a position closer to the side wall 11.

[0080] Furthermore, in this embodiment, the base 42 of the stand 3 is formed, for example, in a circular ring shape. This allows the load of the agitator 2 and the stand 3 to be applied uniformly to the ceiling 12. As a result, the load conditions are further alleviated, and a heavier agitator 2 can be stably installed.

[0081] Furthermore, in this embodiment, for example, the inner diameter L of the base 42 is set so as to satisfy the above formula (1). This increases the area of ​​the load region R1, and prevents the load per unit area (distributed load P1) acting on the ceiling 12 from exceeding the allowable distributed load P. As a result, the load conditions are further relaxed, and a heavier agitator 2 can be installed for a long period of time.

[0082] Furthermore, in this embodiment, the ceiling 12 of the tank body 1 has, for example, an upper wall 121 connected to the side wall 11 of the tank body 1, and a cylindrical protrusion 122 that protrudes upward from the upper wall 121 and forms the opening 15. The base 42 of the stand 3 is installed, for example, on the upper surface of the upper wall 121, not on the upper surface of the protrusion 122. As described above, the side wall 11 has a greater bearing capacity than the ceiling 12. Therefore, by installing the base 42 on the upper wall 121, which is closer to the side wall 11 than the protrusion 122, the load conditions can be alleviated.

[0083] Furthermore, in this embodiment, the gantry 3 further includes a base 5 formed of, for example, mortar (an example of a cement-based material) filled between the ceiling 12 and the base 42. This allows the base 5 to fill the gap formed between the ceiling 12 and the base 42, thereby making it possible to form a suitable contact state between the gantry 3 and the ceiling 12. This allows the load region R1 to be formed so as to correspond to the base 42, and the area of ​​the load region R1 to be secured.

[0084] Furthermore, in this embodiment, for example, the base portion 42 of the stand 3 is disposed so as to surround the fixed portion 41, and the stand 3 has a plurality of beams 43 that connect the fixed portion 41 and the base portion 42 and are arranged radially. By connecting the fixed portion 41 and the base portion 42 with beam members, it is possible to prevent the stand 3 from becoming heavy while ensuring the strength of the stand 3. As a result, it is possible to install a heavier agitator 2.

[0085] Furthermore, the treatment system 1000 of this embodiment includes, for example, a reaction tank 20 that treats the water to be treated by biological treatment, concentrators 40, 50 that thicken sludge separated from the water to be treated, and a digester 60 that treats the sludge supplied from the concentrators 40, 50 by biological treatment. The treatment system 1000 of this embodiment can treat sewage efficiently and at low cost by including, for example, the digester 60 that can be equipped with a high-performance agitator 2 at low cost as described above. Note that the thickener included in the treatment system of the present disclosure may be one that thickens primary sludge discharged from a primary sedimentation tank, or one that thickens excess sludge discharged from a final sedimentation tank, for example.

[0086] [Variations] Modifications of this embodiment will be described below. Fig. 6 is a top view showing a gantry main body in the modification. Specifically, Fig. 6(A) shows a gantry main body 4A in modification 1, Fig. 6(B) shows a gantry main body 4B in modification 2, Fig. 6(C) shows a gantry main body 4C in modification 3, and Fig. 6(D) shows a gantry main body 4D in modification 4. In the following explanation, for the gantry main bodies 4A to 4D in modification 1 to 4, differences from the above-mentioned gantry main body 4 will be mainly described, and the same components as those in the gantry main body 4 will be assigned the same reference numerals and detailed explanations will be omitted.

[0087] As shown in Fig. 6(A), the base 42A of the gantry main body 4A in Modification 1 is formed, for example, in a semicircular ring shape. Also, as shown in Fig. 6(B), the base 42B of the gantry main body 4B in Modification 2 is formed, for example, in an intermittent ring shape. Also, as shown in Fig. 6(C), the base 42C of the gantry main body 4C in Modification 3 is formed, for example, in a polygonal ring shape (a regular dodecagon in this example). Also, as shown in Fig. 6(D), the base 42D of the gantry main body 4D in Modification 4 is configured to include a plurality of segments 421 discretely arranged around the fixing part 41.

[0088] (Addendum) The present disclosure includes the following aspects. [Aspect 1] a tank body having a ceiling portion with an opening formed therein and configured to store the material to be treated; an agitator disposed inside the tank body and having an agitation part for agitating the object to be treated and an exposure part exposed to the outside of the tank body through the opening; A stand supporting the agitator, The mount has a fixing portion to which the exposed portion is fixed, and a base portion installed on an upper surface of the ceiling portion so as to surround the opening. Treatment tank. [Aspect 2] The base portion is formed in an annular shape, The total weight of the frame and the mixer is M [N]. The inner diameter of the base portion is L [mm], The width of the base is d [mm], The allowable distributed load on the ceiling is P [N / mm 2 ], then Satisfy the following formula (1): 2. The treatment vessel of embodiment 1.

number

[0089] 1: Tank body 11: Side wall 12: Ceiling 121: Upper wall part 122:Protrusion 15: Opening 2: Mixer 21: Stirring section 22: Drive unit 3: Stand 4: Stand body 41: Fixed part 42: Base 43:Beam part 5:Foundation 6: Sealing material 20: Reactor 40: Concentrator 50: Concentrator 60: Digestion tank 1000: Processing System

Claims

1. a tank body having a ceiling portion with an opening formed therein and configured to store the material to be treated; an agitator disposed inside the tank body and having an agitating section for agitating the object to be treated and an exposed section exposed to the outside of the tank body through the opening; A stand supporting the agitator, The mount has a fixing portion to which the exposed portion is fixed, and a base portion installed on an upper surface of the ceiling portion so as to surround the opening. Treatment tank.

2. The base portion is formed in an annular shape, The total weight of the frame and the agitator is M [N], The inner diameter of the base portion is L [mm], The width of the base portion is d [mm], The allowable distributed load of the ceiling part is P [N / mm ２ ], then Satisfy the following formula (1): The treatment tank according to claim 1 . [Equation 1]

3. the ceiling portion has an upper wall portion connected to the side wall portion of the tank body, and a cylindrical protrusion portion protruding upward from the upper wall portion and forming the opening, The base portion is installed on the upper surface of the upper wall portion. The treatment tank according to claim 1 .

4. The rack further includes a foundation portion formed by a cement-based material filled between the ceiling portion and the base portion. The treatment tank according to claim 1 .

5. the base portion is disposed so as to surround the fixed portion, The mount has a plurality of beams that connect the fixed portion and the base portion and are arranged radially. The treatment tank according to claim 1 .

6. A treatment system comprising: a reaction tank that treats water to be treated by biological treatment; a concentrating device that concentrates sludge separated from the water to be treated; and a digestion tank that treats the sludge supplied from the concentrating device by biological treatment, The digester comprises: a tank body having a ceiling portion with an opening formed therein and configured to store the sludge; an agitator disposed inside the tank body and having an agitation unit for agitating the sludge and an exposed unit exposed to the outside of the tank body through the opening; a stand supporting the agitator; The mount has a fixing portion to which the exposed portion is fixed, and a base portion installed on an upper surface of the ceiling portion so as to surround the opening. Processing system.

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