Continuous quicksand filter

Abstract

The invention relates to the technical field of water treatment, in particular to a continuous quicksand filter, and provides the continuous quicksand filter aiming at the problems in the prior art, the height position of an air box is reasonably designed, the structure of the air box is optimized, the air stripping effect of compressed air is fully utilized, and an air pipe is prevented from being blocked; the structure of an existing sand washer is improved, the movement path of filter materials in the sand washer is prolonged, collision among the filter materials is increased, the dirty sand cleaning effect is improved, the three-phase separation effect is improved, and the regeneration and reuse rate of the filter materials is increased; meanwhile, the structure of the water distributor is optimized, the water distribution amount in unit cross sectional area is equal, the filtering height of the sand bed is fully utilized, and the filtering effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly to a continuous flow sand filter. Background Art

[0002] A continuous flow sand filter is an efficient filtering device integrating coagulation, clarification, and filtration. Based on the upflow moving bed countercurrent principle and a single homogeneous filter medium, it can effectively remove suspended solids and colloidal substances in water. The continuous flow sand filter realizes simultaneous filtration and sand washing, can operate continuously and automatically for 24 hours without shutdown for backwashing, and can be widely applied to various water treatment processes, especially for industrial process water, and the deep or purification treatment of sewage and industrial wastewater and other fields.

[0003] However, the current continuous flow sand filters have the following problems: 1. The height setting of the air box position of the sand lifting pipe is unreasonable. If the air box position is too low, part of the compressed air is easily discharged from the inlet of the sand lifting pipe, and if the air box position is too high, it is extremely easy to cause poor sand lifting effect; 2. The air inlet direction of the air pipe of the sand lifting device is mostly evenly divided into two opposite air flows along the circumferential horizontal direction of the air box. The gases collide after converging on the opposite side of the air inlet in the air box, resulting in a great reduction in gas energy, poor gas effect, and phenomena such as reverse flow of filter media and entry of filter media into the air pipe in the air box, causing blockage of the air pipe; 3. The three-phase separation effect of the sand washer is poor and there are many dead corners, and the filter media regeneration and cleaning effect is poor; 4. The structure of the water distributor is unreasonable and the utilization rate of the sand bed is low. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a continuous flow sand filter, which effectively solves the problems mentioned in the above background art.

[0005] The technical solutions adopted by the present invention to solve the above problems are as follows:

[0006] A continuous flow sand filter includes a sand filter tank body, a flowing sand filter layer, a water inlet pipe, a water distributor, a sand distributor, a support plate, a pneumatic sand lift pump, a sand lifting pipe, an outlet water, a flushing water discharge pipe, a sand washer, an emptying pipe, and a sand separator. An air box is fixedly connected to the sand lifting pipe at a height of 1 / 5 - 1 / 4 from the bottom upwards. The pneumatic sand lift pump is connected to the air box. A plurality of air inlet through holes are respectively opened on the inner wall of the air box, and through holes communicating with the air inlet through holes are respectively opened on the surface of the sand lifting pipe. After the gas enters the interior of the sand lifting pipe through the air inlet through holes, it flows in a circular and spiral upward direction.

[0007] A water distributor is coaxially arranged on the lower side of the sand lifting pipe. The water distributor is located inside the lower side of the quicksand filtering layer. The water distributor includes a main water distribution pipe and a plurality of water distribution branch pipes fixedly connected to the surface of the main water distribution pipe in a radial distribution centered on the main water distribution pipe. The water distribution branch pipes are respectively connected to the main water distribution pipe. Water distribution holes with downward outlets are respectively arranged on the surfaces of the water distribution branch pipes along the length direction. The water distribution holes are along the radial direction of the water distribution branch pipes, and the hole pitch gradually decreases.

[0008] Sand washing devices are coaxially and fixedly connected to the upper ends of the sand filter tank bodies respectively. The upper end of the sand lifting pipe is connected to the sand washing device. The sand washing device includes a collection cylinder and a sand washing cylinder connected to the lower end of the collection cylinder. The sand washing cylinder is composed of a sand washing cylinder outer ring and a sand washing cylinder inner ring distributed along the outer circle of the sand lifting pipe. Spiral blade plates are respectively fixedly connected to the inner wall of the sand washing cylinder outer ring and the surface of the sand washing cylinder inner ring. The spiral blade plates are respectively arranged longitudinally and staggeredly. The radius of the sand washing cylinder outer ring gradually decreases downward.

[0009] Preferably, the upper part of the sand filter tank body is a cylindrical structure, and the lower part is an inverted conical structure. A quicksand filtering layer is arranged inside the sand filter tank body. A drain pipe is arranged at the bottom of the conical hopper of the inverted conical structure.

[0010] The sand lifting pipe is coaxially and vertically fixed inside the sand filter tank body. The sand washing device is coaxially and fixedly connected to the top of the sand filter tank body. The upper end of the sand lifting pipe is connected to the sand washing device. The sand distributor is located above the sand washing device and is fixedly connected to the top of the sand filter tank body.

[0011] The main water distribution pipe is coaxially and fixedly connected to the surface of the sand lifting pipe. The outlet end of the water inlet pipe is fixedly connected and communicated with the upper side of the surface of the main water distribution pipe. The inlet end of the water inlet pipe is located outside the sand filter tank body. The sand distributor is located below the water distributor and is coaxially and fixedly connected to the surface of the sand lifting pipe.

[0012] The pneumatic sand lifting pump is fixedly connected to the outside of the sand filter tank body. The air outlet end of the pneumatic sand lifting pump is fixedly connected with a connecting pipe, and the other end of the connecting pipe is connected to the sand lifting pipe.

[0013] Preferably, the inlet of the sand lifting pipe is in the shape of a flared mouth.

[0014] Preferably, a plurality of annularly distributed air inlets are respectively arranged on the outer side of the surface of the air box. A circle of air pipes is coaxially arranged outside the air box. The air inlets are respectively communicated and fixedly connected with the air pipes. The end of the connecting pipe far from the pneumatic sand lifting pump is fixedly connected and communicated with the air pipe.

[0015] The air inlet through holes are respectively inclined to the same side and the outlets of the air inlet through holes are all inclined upward. The diameter of the air inlet of the air inlet through hole is larger than the diameter of the air outlet.

[0016] Preferably, a flushing water outlet is provided at a non-central position at the bottom of the collection cylinder. A flushing water discharge pipe is fixedly connected to the opening of the flushing water outlet. An annular baffle is fixedly connected inside the collection cylinder. An annular water collection tank is formed between the collection cylinder and the annular baffle. Water passing openings are respectively provided at two opposite sides on the upper side of the surface of the annular baffle.

[0017] Preferably, the sand separator includes a conical cover located above the annular baffle. An exhaust port is provided at the upper end of the conical cover.

[0018] A sieve cover is coaxially arranged below the conical cover. A plurality of annularly distributed sieve openings are respectively provided on the surface of the sieve cover. The width of the inner end of the sieve opening is smaller than the minimum particle size of the filter material.

[0019] Preferably, an overflow weir is fixedly connected to the top end inside the sand filtration tank body. The height of the overflow weir is lower than the top of the sand filtration tank body and higher than the water passing opening.

[0020] Preferably, an impeller is rotatably connected to the inner side of the conical cover. A transmission shaft is fixedly connected coaxially in the middle of the impeller. A driving gear is fixedly connected to the middle of the upper end of the transmission shaft. A transmission gear is meshed with one side of the driving gear. The transmission gear is rotatably connected to the inner wall of the conical cover. A rotating plate is coaxially arranged below the driving gear. The rotating plate is rotatably connected to the inner wall of the conical cover. A groove is coaxially opened downward at the upper end of the rotating plate. An internal gear is fixedly connected coaxially inside the groove. The transmission gear is meshed with the internal gear.

[0021] A scraper is arranged on the inner wall surface of the sieve cover. One end of the scraper is fixedly connected with a linkage plate. The other end of the linkage plate is fixedly connected with the rotating plate.

[0022] Preferably, a collection cover is coaxially arranged above the impeller. Transmission pipes are respectively fixedly connected and communicated with two opposite sides at the upper end of the collection cover. Spray holes are respectively provided on the scraper along the length direction of the scraper. A transition cylinder is fixedly connected to the end of the scraper far away from the inner wall of the sieve cover. The outer ends of the spray holes are respectively communicated with the transition cylinder. The other ends of the transmission pipes are fixedly connected and communicated with the transition cylinder.

[0023] Preferably, an annular inclined surface block is fixedly connected to the lower side of the inner wall of the annular baffle. The upper end inner side of the annular inclined surface block inclines downward.

[0024] The structure of the present invention is novel, ingeniously conceived, simple and convenient to operate, and has the following advantages compared with the prior art:

[0025] By reasonably designing the height position of the air box and optimizing the air box structure, the air-lifting effect of compressed air is fully utilized to avoid the blockage of the air pipe; and the structure of the existing sand washer is improved to extend the movement path of the filter media in the sand washer, increase the collision between the filter media, improve the cleaning effect of the dirty sand, enhance the three-phase separation effect, and increase the recycling rate of the filter media; at the same time, the structure of the water distributor is optimized to ensure that the water distribution amount per unit cross-sectional area is equal, fully utilize the filtration height of the sand bed, improve the filtration effect, and avoid the loss of the filter media. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 FIG. 1 is a first schematic diagram of the overall structure of a continuous-flow sand filter according to the present invention.

[0027] Figure 2 FIG. 2 is a second schematic diagram of the overall structure of a continuous-flow sand filter according to the present invention.

[0028] Figure 3 FIG. 3 is a schematic diagram of the structure of the water distributor of a continuous-flow sand filter according to the present invention.

[0029] Figure 4 FIG. 4 is a schematic diagram of the structure of the water distribution holes of a continuous-flow sand filter according to the present invention.

[0030] Figure 5 FIG. 5 is a schematic diagram of the structure of the air box of a continuous-flow sand filter according to the present invention.

[0031] Figure 6 FIG. 6 is a first schematic diagram of the structure of the air intake through holes of a continuous-flow sand filter according to the present invention.

[0032] Figure 7 FIG. 7 is a second schematic diagram of the structure of the air intake through holes of a continuous-flow sand filter according to the present invention.

[0033] Figure 8 FIG. 8 is a schematic diagram of the structure of the sand washer of a continuous-flow sand filter according to the present invention.

[0034] Figure 9 FIG. 9 is a schematic diagram of the structure of the sand separator of a continuous-flow sand filter according to the present invention.

[0035] Figure 10 FIG. 10 is a schematic diagram of the structure of the scraper installation of a continuous-flow sand filter according to the present invention.

[0036] Figure 11 FIG. 11 is a schematic diagram of the structure of the impeller installation of a continuous-flow sand filter according to the present invention.

[0037] Reference numerals in the figure: 1 - sand filter tank body, 2 - quicksand filter layer, 3 - water inlet pipe, 4 - water distributor, 5 - sand distributor, 6 - support plate, 7 - pneumatic sand lift pump, 8 - sand lift pipe, 9 - water outlet pipe, 10 - flushing water discharge pipe, 11 - sand washer, 12 - emptying pipe, 13 - sand separator, 14 - overflow weir, 51 - main water distribution pipe, 52 - water distribution branch pipe, 53 - water distribution hole, 81 - sand lift pipe inlet, 82 - air box, 83 - air pipe, 821 - air pipe connection port, 822 - air inlet, 823 - air intake through hole, 111 - collection cylinder, 112 - conical cover, 113 - exhaust port, 114 - flushing water outlet, 115 - annular baffle, 116 - water collection tank, 117 - sand washing cylinder, 118 - sand discharge port, 1171 - outer ring of sand washing cylinder, 1172 - inner ring of sand washing cylinder, 1173 - spiral vane plate, 15 - sieve cover, 16 - annular inclined block, 17 - impeller, 18 - collection cover, 19 - scraper, 20 - transition cylinder, 21 - spray hole, 22 - transmission pipe, 23 - linkage plate, 24 - rotating plate, 25 - internal gear, 26 - transmission gear, 27 - driving gear, 28 - transmission shaft. Detailed implementation mode

[0038] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

[0039] As Figures 1-11 shown, the present invention provides a continuous quicksand filter, as Figure 2 shown, including a sand filter tank body 1, a quicksand filter layer 2, a water inlet pipe 3, a water distributor 4, a sand distributor 5, a support plate 6, a pneumatic sand lift pump 7, a sand lift pipe 8, a water outlet pipe 9, a flushing water discharge pipe 10, a sand washer 11, an emptying pipe 12, and a sand separator 13;

[0040] The upper part of the sand filter tank body 1 is a cylindrical structure, and the lower part is an inverted conical structure. A quicksand filter layer 2 is arranged inside the sand filter tank body 1 and is filled with filter materials such as sand or porcelain sand; an emptying pipe 12 is arranged at the bottom of the conical hopper of the inverted conical structure. The emptying pipe 12 is used to discharge the quicksand filter layer 2, which is convenient for overall replacement of the quicksand filter layer; a valve is installed at the outlet of the emptying pipe 12 to facilitate the opening and closing of the emptying pipe 12.

[0041] The sand lift pipe 8 is vertically fixed coaxially inside the sand filter tank body 1, the sand washer 11 is coaxially fixedly connected to the top of the sand filter tank body 1, the upper end of the sand lift pipe 8 is connected to the sand washer 11, the sand separator 13 is located above the sand washer 11, and the sand separator 13 is fixedly connected to the top of the sand filter tank body 1;

[0042] The main water distribution pipe 51 is coaxially and fixedly connected to the surface of the sand lifting pipe 8. The outlet end of the water inlet pipe 3 is fixedly connected and communicated with the upper side of the surface of the main water distribution pipe 51. The inlet end of the water inlet pipe 3 is located outside the sand filtration tank body 1. The lower end of the main water distribution pipe 51 is fixedly connected and communicated with the water distributor 4. The water distributor 4 is arranged in the flowing sand filtration layer 2. The sand distributor 5 is located below the water distributor 4 and is coaxially and fixedly connected to the surface of the sand lifting pipe 8, and is supported by the support plate 6. The outer ends of the support plate 6 are respectively fixedly connected to the inner wall of the sand filtration tank body 1. The support plate 6 is supported by 3 points evenly welded on the inner wall of the sand filtration tank body 1 to form an equilateral triangle structure to support the water distributor 4. The sand distributor 5 has a structure with a conical surface facing upwards. The sewage flowing out of the water distributor 4 fills the lower side inside the sand filtration tank body 1 and then flows upwards. During the flowing process, most of the suspended substances in the sewage are first filtered by the filter material of the lower flowing sand filtration layer 2. And during the flowing process of the sewage, the flowing sand filtration layer 2 is in a dispersed state dredged by the water flow. The filter material carrying the sewage suspended substances in the lower layer of the flowing sand filtration layer 2 slides down to the lower part of the sand distributor 5 under the action of the inclined surface at the upper end of the sand distributor 5 and is concentrated and collected at the bottom of the inverted conical structure at the lower end inside the sand filtration tank body 1. The sand distributor 5 can not only support the filter material, but also effectively guide the filter material carrying the sewage suspended substances to the lower side inside the sand filtration tank body 1 while the filter material filters the sewage, which is convenient for the sand lifting pipe 8 to lift the fine sand.

[0043] The pneumatic sand lift pump 7 is fixedly connected to the outside of the sand filtration tank body 1. The air outlet end of the pneumatic sand lift pump 7 is fixedly connected with a connecting pipe, and the other end of the connecting pipe is connected to the sand lifting pipe 8. The pneumatic sand lift pump 7 transmits compressed air into the sand lifting pipe 8 through the connecting pipe. During the flowing process of the compressed air, under the air-lift action, the mixture of the filter material and the sewage rises along the sand lifting pipe 8 to the sand washer 11. The inlet 81 of the sand lifting pipe 8 is in the shape of a bell mouth, so that the sand lifting pipe can suck the filter material at the bottom of the sand filtration tank body 1 as much and as smoothly as possible.

[0044] Furthermore, the air box 82 is fixedly connected to the surface of the sand lifting pipe 8, and a plurality of air inlets 822 distributed in an annular shape are respectively provided on the outer side of the surface of the air box 82. A circle of air pipes 83 are coaxially arranged on the outer side of the air box 82. The air inlets 822 are respectively connected to and fixedly connected with the air pipes 83. An air pipe connecting port 821 is provided on one side of the surface of the air pipe 83. One end of the connecting pipe away from the pneumatic sand lifting pump 7 is fixedly connected and connected to the air pipe connecting port 821 on the surface of the air pipe 83. The compressed air in the pneumatic sand lifting pump 7 enters the air pipe 83 through the connecting pipe and enters the sand lifting pipe 8 through the air inlet of the air box 82. A plurality of air inlet holes 823 are respectively provided on the inner wall of the air box 82, and through holes connected to the air inlet holes 823 are respectively provided on the surface of the sand lifting pipe 8. The air inlet holes 823 are respectively inclined to the same side, and the outlets of the air inlet holes 823 are all inclined upward, so that the gas When the gas enters the sand lifting pipe 8 through the air inlet hole 823, it flows in a circular and spiral upward direction. The circular motion when the gas is ejected can minimize the obstruction encountered by the gas after ejection, maximize the energy and air lifting effect of the gas, and improve the air lifting effect of the gas while flowing in a spiral upward direction. Furthermore, the diameter of the air inlet of the air inlet hole 823 is larger than the diameter of the air outlet, so that the gas can enter the sand lifting pipe 8 through the air inlet more effectively, and effectively increase the flow rate while being ejected through the air inlet hole 823, so that the flow rate of the air flow is further increased, and the air lifting effect of the gas is further improved; the aperture of the air inlet hole 823 at the connection between the inside of the air box 82 and the sand lifting pipe 8 is smaller than the minimum particle size of the filter material of the quicksand filter layer 2, so as to avoid the filter material from entering the air box 82, causing filter material backflow, and filter material entering the air inlet hole 823, causing blockage problems;

[0045] The air box 82 is located at 1 / 5-1 / 4 of the height upward from the bottom of the sand lifting pipe 8, with the height of 1 / 5 being the main position. When in use, the sand lifting pipe 8 with the corresponding air box 82 height can be selected according to different hydraulic conditions to minimize gas leakage from the bottom of the sand lifting pipe 8 and maximize the air lifting effect of compressed air.

[0046] The sand washing device 11 includes a collecting cylinder 111, which is fixedly connected to the upper end of the inner wall of the sand filter tank body 1, and a flushing water outlet 114 is provided at a non-center position at the bottom of the collecting cylinder 111. A flushing water outlet 114 is fixedly connected to the opening of the flushing water outlet 114. A flushing water discharge pipe 10 is fixedly connected to the inside of the collecting cylinder 111. An annular baffle 115 is fixedly connected to the inside of the collecting cylinder 111. An annular water collecting trough 116 is formed between the collecting cylinder 111 and the annular baffle 115. Water outlets are respectively provided on the corresponding two sides of the upper side of the surface of the annular baffle 115. The flushing water containing a large amount of suspended matter enters the water collecting trough 116 through the water outlet of the annular baffle 115 as the water level rises, and enters the flushing water discharge pipe 10 through the flushing water outlet 114 for discharge.

[0047] The sand separator 13 includes a conical cover 112 located above the annular baffle 115. An exhaust port 113 is provided at the upper end of the conical cover 112. The mixture of filter media and sewage in the sand lifting pipe 11 is discharged from the upper end of the sand lifting pipe 11 and enters the inner side of the annular baffle 115. The gas is collected by the conical cover 112 and discharged through the exhaust port 113, realizing the separation of the mixture formed by the filter media and the flushing water from the air. A sieve cover 15 is coaxially arranged below the conical cover 112. A plurality of annularly distributed sieve openings are respectively provided on the surface of the sieve cover. The width of the inner end of the sieve opening is smaller than the minimum particle size of the filter media, which is used to filter the filter media. When the water level rises, the flushing water containing a large amount of suspended matter flows out through the sieve openings and enters the water collecting tank 116 through the water passing openings. The filter media will be blocked by the sieve openings on the inner side of the annular baffle 15, preventing the filter media from entering the water collecting tank 116 along with the flow of the flushing water during the temporary suspension in the flushing water, resulting in the loss of the filter media;

[0048] An overflow weir 14 is fixedly connected to the inner top of the sand filter tank body 1. The height of the overflow weir 14 is lower than the top of the sand filter tank body 1 and higher than the water passing opening. During the rising process of the water flow, the flushing water for cleaning the filter media first enters the water collecting tank 116 through the water passing opening, then is discharged through the flushing water discharge pipe 10, and then the purified water overflows into the overflow weir 14 during the rising process. An outlet pipe 9 is provided at the upper position of the connection between the overflow weir 14 and the sand filter tank body 1, and the treated wastewater flows out here.

[0049] Furthermore, an impeller 17 is rotatably connected to the inner side of the conical cover 112. A transmission shaft 28 is fixedly connected coaxially in the middle of the impeller 17. A driving gear 27 is fixedly connected to the middle of the upper end of the transmission shaft 28. A transmission gear 26 is engaged with one side of the driving gear 27. The transmission gear 26 is rotatably connected to the inner wall of the conical cover 112. A rotating plate 24 is coaxially arranged below the driving gear 27. The rotating plate 24 is rotatably connected to the inner wall of the conical cover 112. A groove is coaxially opened downward at the upper end of the rotating plate 24. An internal gear 25 is fixedly connected coaxially inside the groove. The transmission gear 26 is engaged with the internal gear 25. The gas in the sand lifting pipe 11 is collected by the conical cover 112 and flows upward. When passing through the impeller 17, it can drive the impeller 17 to rotate. When the impeller 17 rotates, it drives the driving gear 27 to rotate under the transmission of the transmission shaft 28, and drives the internal gear 25 to rotate under the meshing transmission of the transmission gear 26;

[0050] A scraping plate 19 is provided on the inner wall surface of the screening cover 15. One end of the scraping plate 19 is fixedly connected to a linkage plate 23, and the other end of the linkage plate 23 is fixedly connected to a rotating plate 24. When the internal gear 25 rotates, the rotating plate 24 rotates synchronously, and drives the scraping plate 19 to slide on the inner wall of the screening cover 15 through the transmission of the linkage plate 23, which can clean the filter material attached to the inner wall of the screening cover 15, achieving the effect of preventing the screening port from being blocked. Moreover, when the transmission gear 26 and the internal gear 25 are in transmission, it is a speed-reducing transmission, so that the scraping plate 19 moves slowly on the inner wall surface of the screening cover 15 without affecting the normal sedimentation of the filter screen.

[0051] A collection cover 18 is coaxially arranged above the impeller 17. Corresponding sides at the upper end of the collection cover 18 are respectively fixedly connected and communicated with transmission pipes 22. The scraping plate 19 is respectively provided with spray holes 21 along the length direction of the scraping plate 19. One end of the scraping plate 19 away from the inner wall of the screening cover 15 is fixedly connected to a transition cylinder 20, and the outer ends of the spray holes 21 are respectively communicated with the transition cylinder 20. The other end of the transmission pipe 22 is fixedly connected and communicated with the transition cylinder 22. The gas collected by the conical cover 112 is collected again by the collection cover 18 and enters the spray holes 21 through the transmission pipes 22, and can be ejected through the spray holes during the movement of the scraping plate 19. During the process of the scraping plate 19 cleaning the inner wall of the screening cover 15, the gas ejected through the spray holes 21 acts on the water to form disturbing bubbles, which disperse the attachments attached to the inner wall of the screening cover 15, further improving the cleaning effect on the inner wall of the screening cover 15.

[0052] The bottom of the collection cylinder 111 is connected to a sand washing cylinder 117. An annular inclined surface block 16 is fixedly connected to the lower side of the inner wall of the annular baffle 115. The upper end inner side of the annular inclined surface is inclined downward to form a guiding surface inclined towards the sand washing cylinder 117 on the inner side, which is convenient for guiding the filter material flowing out from the upper end of the sand lifting pipe 8 into the sand washing cylinder 117. The sand washing cylinder 117 is composed of a sand washing cylinder outer ring 1171 and a sand washing cylinder inner ring 1172 distributed along the outer circle of the sand lifting pipe 8. The sand washing cylinder outer ring 1171 and the sand washing cylinder inner ring 1172 are coaxially arranged. The sand washing cylinder inner ring 1172 is located inside the sand washing cylinder outer ring 1171 and a fixing plate is fixedly connected along the radial direction at the upper end for making the sand washing cylinder outer ring 1171 and the sand washing cylinder inner ring 1172 form an integral body. The upper end of the sand washing cylinder outer ring 1171 is fixedly connected to the bottom of the collection cylinder 111. The sand washing cylinder 117 is used to separate the washing water and the filter material, realizing the regeneration and reuse of the filter material and returning it to the sand filter tank body for reuse.

[0053] Inside the sand washing cylinder 117, downwardly inclined spiral vane plates 1173 are fixedly connected respectively, and the spiral vane plates 1173 are distributed on the surface of the outer ring 1171 of the sand washing cylinder and the surface of the inner ring 1172 of the sand washing cylinder respectively; the inclination angle β of the spiral vane plate 1173 with respect to the horizontal plane is 30°, which can well obstruct the filter material during the falling process of the filter material. After the filter material falls onto the surface of the spiral vane plate 1173, it then slides down through the action of the inclined surface without affecting the falling of the filter material. During the process of the filter material falling onto the surface of the spiral vane plate 1173, it can effectively collide and rub the filter material, and then carry away the suspended matter on the surface of the filter material during the reverse scouring process of the upward flow, effectively cleaning the filter material;

[0054] The spiral vane plates 1173 on the surface of the outer ring of the sand washing cylinder and the spiral vane plates 1173 on the surface of the inner ring of the sand washing cylinder are longitudinally staggered with each other. During the falling process of the filter material, it can maximize the number of collisions and the friction effect of the dirty sand in the sand washing cylinder 117, enabling the upward flow to fully clean the filter material. Further, the radius of the outer ring 1171 of the sand washing cylinder of the sand washer gradually decreases, making the friction during the downward cleaning movement of the filter material stronger, and further increasing the cleaning effect on the filter material.

[0055] Further, the sand discharge port 118 formed by the outer ring 1171 and the inner ring 1172 of the sand washing cylinder at the bottom of the sand washing cylinder 117 is 8 times the minimum particle size of the filter material of the flowing sand filter layer 2, to ensure that the filter material can smoothly pass through the sand discharge port 118 and return to the sand filter tank body 1.

[0056] As Figures 2-7 shown, the water distributor includes a water distribution main pipe 51 located at the central position of the sand filter tank body 1, and 8 water distribution branch pipes 52 which are evenly distributed radially. The water distribution branch pipes 52 are fixedly connected to and communicate with the water distribution main pipe 51 respectively, and can stably and evenly distribute the wastewater to be filtered to the water distribution branch pipes 52;

[0057] The water distribution main pipe 51 is vertically arranged, and the water distribution branch pipes 52 are arranged with an inclination angle α = 10° downward with the water distribution main pipe 51 as the center, to increase the distance d from the water distribution holes of the water distribution branch pipe 51 to the upper top surface of the filter material, extend the filtration distance, and further improve the filtration effect.

[0058] The water distribution holes 53 of the water distribution branch pipes 52 are vertically downward for the sewage to flow out. A plurality of water distribution holes 53 are respectively opened on the surface of a single water distribution branch pipe 52. The outlet aperture of the water distribution holes 53 is smaller than the minimum particle size of the filter material of the flowing sand filter layer, to avoid the filter material of the flowing sand filter layer from blocking the water outlet holes 53 of the water distribution branch pipes. The water distribution holes 53 of the water distribution branch pipes are along the radial direction of the water distribution branch pipes 52, and the hole pitch gradually decreases, to ensure that the water distribution amount per unit cross-sectional area is equal, thereby effectively exerting the filtration effect of the flowing sand filter layer 2 within the range.

[0059] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains may make various modifications or supplements to the described specific embodiments or use similar means to replace them, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A continuous-flow sand filter, comprising a sand filter tank body (1), a sand filtration layer (2), a water inlet pipe (3), a water distributor (4), a sand distributor (5), a support plate (6), a pneumatic sand lifting pump (7), a sand lifting pipe (8), an outlet water (9), a flushing water discharge pipe (10), a sand washer (11), an emptying pipe (12), and a sand separator (13), characterized in that: A gas box (82) is fixedly connected to the sand lifting pipe (8) at a height of 1 / 5 - 1 / 4 from the bottom upwards. The pneumatic sand lifting pump (7) is connected to the gas box (82). A plurality of air inlet through holes (823) are respectively formed in the inner wall of the gas box (82). Through holes communicating with the air inlet through holes (823) are respectively formed on the surface of the sand lifting pipe (8). After the gas enters the interior of the sand lifting pipe (8) through the air inlet through holes (823), it flows in a circular and spiral upward direction; A water distributor (4) is coaxially arranged below the sand lifting pipe (8). The water distributor (4) is located inside the lower side of the flowing sand filter layer (2). The water distributor (4) includes a water distribution main pipe (51) and a plurality of water distribution branch pipes (52) fixedly connected to the surface of the water distribution main pipe (51) in a radial manner centered on the water distribution main pipe. The water distribution branch pipes (52) are respectively connected to the water distribution main pipe (51). Water distribution holes (53) with downward outlets are respectively formed on the surface of the water distribution branch pipes (52) along the length direction. The water distribution holes (53) are in the radial direction of the water distribution branch pipes (52), and the hole pitch gradually decreases; A sand washing device (11) is coaxially and fixedly connected to the upper end of the sand filter tank body (1). The upper end of the sand lifting pipe (8) is connected to the sand washing device (11). The sand washing device (11) includes a collection cylinder (111) and a sand washing cylinder (117) connected to the lower end of the collection cylinder (111). The sand washing cylinder (117) is composed of a sand washing cylinder outer ring (1171) distributed along the outer circle of the sand lifting pipe (8) and a sand washing cylinder inner ring (1172). Spiral blade plates (1173) are respectively fixedly connected to the inner wall of the sand washing cylinder outer ring (1171) and the surface of the sand washing cylinder inner ring (1172). The spiral blade plates (1173) are respectively arranged longitudinally in a staggered manner. The radius of the sand washing cylinder outer ring (1171) gradually decreases downward; 2. The continuous sand filter according to claim 1, wherein: The upper part of the sand filter tank body (1) is a cylindrical structure, and the lower part is an inverted conical structure. A flowing sand filter layer (2) is arranged inside the sand filter tank body (1). An emptying pipe (12) is arranged at the bottom of the conical hopper of the inverted conical structure; The sand lifting pipe (8) is vertically and coaxially fixed inside the sand filter tank body (1). The sand washing device (11) is coaxially and fixedly connected to the top of the sand filter tank body (1). The upper end of the sand lifting pipe (8) is connected to the sand washing device (11). The sand distributor (13) is located above the sand washing device (11), and the sand distributor (13) is fixedly connected to the top of the sand filter tank body (1); The water distribution main pipe (51) is coaxially and fixedly connected to the surface of the sand lifting pipe (8). The outlet end of the water inlet pipe (3) is fixedly connected and communicated with the upper side surface of the water distribution main pipe (51). The inlet end of the water inlet pipe (3) is located outside the sand filter tank body (1). The sand distributor (5) is located below the water distributor (4) and is coaxially and fixedly connected to the surface of the sand lifting pipe (8); The pneumatic sand lifting pump (7) is fixedly connected to the outside of the sand filter tank body (1). The air outlet end of the pneumatic sand lifting pump (7) is fixedly connected with a connecting pipe, and the other end of the connecting pipe is connected to the sand lifting pipe (8).

3. The continuous sand filter according to claim 1, characterized in that: The inlet (8(1)) of the sand lifting pipe (8) is in the shape of a bell mouth.

4. A continuous sand filter according to claim 1, characterized in that: On the outer surface of the air box (82), a plurality of annularly distributed air inlets (822) are respectively provided. A circle of air pipes (83) is coaxially arranged outside the air box (82). The air inlets (822) are respectively connected and fixedly connected to the air pipes (83). One end of the connecting pipe away from the pneumatic sand pump (7) is fixedly connected and communicated with the air pipe (83). The air intake through holes (823) are inclined to the same side respectively, and the outlets of the air intake through holes (823) are all inclined upward. The diameter of the air inlet of the air intake through hole (823) is larger than the diameter of the air outlet.

5. A continuous flow sand filter according to claim 1, characterized in that: At a non-central position at the bottom of the collecting cylinder (111), a flushing water outlet (114) is provided. A flushing water discharge pipe (10) is fixedly connected to the opening of the flushing water outlet (114). An annular baffle (115) is fixedly connected inside the collecting cylinder (111). An annular water collecting tank (116) is formed between the collecting cylinder (111) and the annular baffle (115). Water passing openings are respectively provided on the upper side of the surface of the annular baffle (115) at corresponding two sides.

6. The continuous sand filter according to claim 1, wherein: The sand separator (13) includes a conical cover (112) located above the annular baffle (115). An exhaust port (13) is provided at the upper end of the conical cover (112). A sieve dividing cover (15) is coaxially arranged below the conical cover (112). A plurality of annularly distributed sieve dividing openings are respectively provided on the surface of the sieve dividing cover (15). The width of the inner end of the sieve dividing opening is smaller than the minimum particle size of the filter material.

7. The continuous sand filter according to claim 1, characterized in that: An overflow weir (14) is fixedly connected to the inner top of the sand filter tank body (1). The height of the overflow weir (14) is lower than the top of the sand filter tank body (1), and the height of the overflow weir (14) is higher than the water passing opening.

8. The continuous flow sand filter according to claim 6, characterized in that: An impeller (17) is rotatably connected to the inner side of the conical cover (112). A transmission shaft (28) is coaxially fixedly connected to the middle of the impeller (17). A driving gear (27) is fixedly connected to the middle of the upper end of the transmission shaft (28). A transmission gear 2 (6) is meshed with one side of the driving gear (27). The transmission gear 2 (6) is rotatably connected to the inner wall of the conical cover (112). A rotating plate (24) is coaxially arranged below the driving gear 2 (7). The rotating plate (24) is rotatably connected to the inner wall of the conical cover (112). A groove is coaxially opened downward at the upper end of the rotating plate (24). An internal gear (25) is coaxially fixedly connected inside the groove. The transmission gear (26) is meshed with the internal gear 2 (5). A scraping plate (19) is arranged on the inner wall surface of the sieve dividing cover (15). One end of the scraping plate (19) is fixedly connected to a linkage plate (23). The other end of the linkage plate (23) is fixedly connected to the rotating plate (24).

9. The continuous sand filter according to claim 8, wherein: A collecting hood (18) is coaxially arranged on the upper side of the impeller (17). At both sides corresponding to the upper end of the collecting hood (18), there are respectively fixedly connected and communicated with a transmission pipe (22). The scraper (19) is respectively provided with spray holes (21) arranged along the length direction of the scraper (19). One end of the scraper (19) far from the inner wall of the screening hood (15) is fixedly connected with a transition cylinder (20). The outer ends of the spray holes (21) are respectively communicated with the transition cylinder (20). The other end of the transmission pipe (22) is fixedly connected with and communicated with the transition cylinder (22).

10. A continuous sand filter according to claim 6, characterized in that: An annular inclined plane block (16) is fixedly connected to the lower side of the inner wall of the annular baffle (115), and the inner side of the upper end of the annular inclined plane block (16) inclines downward.

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