Filtering equipment for kitchen waste slurry

Abstract

The embodiment of the invention relates to the technical field of environmental protection, and discloses kitchen waste slurry filtering equipment which comprises a first screen mesh, a second screen mesh and a filter screen, the first screen mesh is provided with a plurality of first screen holes, and the first screen holes are used for filtering kitchen waste slurry to obtain first filtrate; the overflow weir plate is arranged below the first screen and used for receiving the first filtrate, and an outlet weir is arranged on the overflow weir plate; the second screen mesh is arranged below the overflow weir plate, the mesh surface of the second screen mesh is a single curved surface, and the straight line edge on one side of the single curved surface is aligned with the outlet weir and used for receiving the first filtrate overflowing from the outlet weir; the second screen is provided with a plurality of second screen holes, the area of the second screen holes is smaller than that of the first screen holes, and the second screen holes are used for filtering the first filtrate when the first filtrate flows in the arc direction of the single curved surface. By means of the mode, the kitchen garbage slurry filtering device achieves the effect of improving the filtering effect on kitchen garbage slurry.

Description

Technical Field

[0001] The present application relates to the field of environmental protection technology, and in particular to a filtering device for kitchen waste slurry. Background Art

[0002] Kitchen waste refers to garbage generated in residents' daily lives and in food processing, catering services, unit meal supply and other activities, including discarded vegetable leaves, leftovers, leftover rice, fruit peels, egg shells, tea dregs, bones, etc. Its main sources are home kitchens, restaurants, hotels, canteens, markets and industries related to food processing.

[0003] The slurry generated during the pretreatment of kitchen waste (including restaurant kitchen waste, household kitchen waste and other kitchen waste) mainly includes hopper and equipment drainage, solid-liquid separation slurry and slurry separated by three-phase oil extractor. This type of slurry has high solid content, high oil content, viscous slurry, and many impurities such as long fiber plastics. The commonly used filtering and impurity removal equipment in the field of kitchen waste pretreatment aims to prevent the three-phase oil extractor from clogging. Generally, centrifugal deslagging machines are used, and the filter sieve holes are generally around 5mm. At present, the preparation of carbon source from kitchen waste slurry is an emerging resource utilization method. For example, Chinese patents with publication numbers CN116553642A, CN118307134A and CN221117047U use membrane filtration to prepare carbon source. However, before membrane filtration, the long impurities need to be filtered out to avoid damaging the membrane elements and clogging the membrane tubes. Subject to the membrane feed requirements, the particle size of the membrane feed material is generally required to be ≤1mm. Of course, the smaller the particle size of the material, the more conducive it is to the continuous and stable operation of the membrane system.

[0004] The prior art generally uses a layer of filter screen to filter the slurry of kitchen waste. The filtrate obtained by filtration also contains a large amount of solid debris, which is difficult to meet the feed requirements of the membrane system.

[0005] Therefore, how to improve the filtering effect of kitchen waste slurry has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above problems, an embodiment of the present application provides a filtering device for kitchen waste slurry, which is used to improve the filtering effect of kitchen waste slurry.

[0007] According to one aspect of an embodiment of the present application, a filtering device is provided for filtering kitchen waste slurry, the filtering device comprising: a first screen having a plurality of first screen holes, the first screen holes being used to filter the kitchen waste slurry to obtain a first filtrate; an overflow weir plate, arranged below the first screen, for receiving the first filtrate, an outlet weir being arranged on the overflow weir plate; a second screen, arranged below the overflow weir plate, the mesh surface of the second screen being a single curved surface, the straight line edge on one side of the single curved surface being aligned with the outlet weir, for receiving the first filtrate overflowing from the outlet weir; the second screen having a plurality of second screen holes, the area of ​​the second screen holes being smaller than the area of ​​the first screen holes, the second screen holes being used to filter the first filtrate when the first filtrate flows along the arc direction of the single curved surface.

[0008] Preferably, both the first screen and the second screen are wedge-shaped screens, and the long side of the second screen hole is perpendicular to the direction of gravity.

[0009] Preferably, the arc of the single-curved surface is in the shape of a maximum speed curve.

[0010] Preferably, the filtering device also includes a driving assembly; the first screen is cylindrical and connected to the driving assembly, and is used to rotate under the drive of the driving assembly to filter out the first solid impurities in the kitchen waste slurry to obtain the first filtrate; a feed port is provided at one end of the first screen, and a discharge port is provided at the other end, the feed port is used to input the kitchen waste slurry, and the discharge port is used to output the first solid impurities; a spiral blade is provided in the first screen, and the spiral blade has the central axis of the cylinder as the blade axis and is distributed on the inner wall of the first screen, and is used to transport the first solid impurities to the discharge port.

[0011] Preferably, the pitch of the portion of the spiral blade close to the discharge port is greater than the pitch of the portion of the spiral blade close to the feed port.

[0012] Preferably, an angle is formed between the central axis of the first screen and the horizontal plane, the angle ranges from 0 to 10 degrees, and the discharge port is higher than the feed port.

[0013] Preferably, the second screen is used to filter out the second solid impurities in the first filtrate to obtain a second filtrate; the filtration equipment also includes a filtrate receiving trough and a material receiving trough, the filtrate receiving trough is aligned with the second screen and arranged below the second screen, for receiving the second filtrate, and the material receiving trough is close to the straight edge on the other side of the second screen, for collecting the second solid impurities that slide off the second screen.

[0014] Preferably, the filtering device further comprises: a plurality of flushing nozzles distributed along the central axis direction of the first screen and fixed at the oblique upper side of the first screen; and a flushing spray gun disposed at the upper side of the second screen.

[0015] Preferably, the filtering device further comprises a water baffle, and the water baffle is arranged close to the feed inlet.

[0016] Preferably, the filtering equipment also includes: a water inlet pipe connected to the filtrate receiving trough; multiple water outlet pipes, respectively connected to the flushing spray gun and multiple flushing nozzles; an electromagnetic valve connected to the water inlet pipe, used to extract the second filtrate in the filtrate receiving trough, and transport the extracted second filtrate to multiple water outlet pipes.

[0017] The embodiment of the present application filters the solid impurities with larger volume in the kitchen waste slurry through the first sieve holes of the first sieve to obtain the first filtrate, and then filters the long debris with smaller volume in the first filtrate through the second sieve holes on the second sieve whose area is smaller than the first sieve holes, so as to achieve fine filtration of the kitchen waste slurry through the layered arrangement of the first filter screen and the second filter screen, thereby improving the filtering effect of the kitchen waste slurry; by setting the mesh surface of the second sieve to be a single curved surface, when the first filtrate is filtered through the second sieve, the first filtrate can flow naturally on the single curved surface under the action of gravity, so that when the second sieve holes on the single curved surface are partially blocked, the first filtrate can still flow along the single curved surface under the action of gravity. The first filtrate flows in the arc direction of the surface to achieve filtration through the unblocked second sieve holes on the single curved surface, thereby improving the filter hole utilization rate and filtration efficiency of the second filter screen; by arranging an overflow weir plate between the first screen screen and the second screen screen as a connection, and arranging an outlet weir with a straight edge on one side of the single curved surface horizontally arranged and aligned with the overflow weir plate, the first filtrate overflowing from the outlet weir can be spread more evenly on the second screen screen to fully utilize the filtration area of ​​the second screen screen, and the first filtrate can flow from the straight edge on one side of the single curved surface to the straight edge on the other side to extend the flow path of the first filtrate on the single curved surface, thereby improving the utilization rate of the second sieve holes on the second screen screen and fully utilizing the filtration area of ​​the second screen screen.

[0018] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A three-dimensional diagram of a filtering device provided in an embodiment of the present application is shown; Figure 2 A three-dimensional view of the filtering device provided in an embodiment of the present application from another angle is shown; Figure 3A schematic diagram of a part of the internal structure of the filtering device provided in an embodiment of the present application is shown; Figure 4 A cross-sectional view of a filtering device provided in an embodiment of the present application is shown; Figure 5 A side view of a filtering device provided in an embodiment of the present application is shown; Figure 6 A schematic diagram of the internal structure of another part of the filtering device provided in an embodiment of the present application is shown.

[0020] The reference numerals in the specific implementation manner are as follows: 1. Filtration equipment; 101. Feed pipe; 102. Feed distribution trough; 103. Overflow weir trough; 104. Support angle steel; 105. Water retaining plate; 106. Flushing water retaining plate; 201, first screen; 202, spiral blade; 203, front support roller of drum; 204, drum limit ring; 205, driving reduction motor; 206, large gear; 207, small gear; 208, driving chain; 209, discharge port; 210, overflow weir plate; 211, gear water retaining plate; 212, rear support roller of drum; 301, second screen; 302, filtrate receiving trough; 303, material receiving trough; 304, filtrate outlet under the sieve; 305, material outlet on the sieve; 401, flushing pump; 402, flushing pipeline; 403, flushing nozzle; 404, flushing spray gun; 405, solenoid valve; 501, adjustable legs; 502, crossbeam; 503, sealed housing of equipment; 504, quick-open inspection port; 505, quick-open observation port; 506, quick-open door; 507, deodorizing port; 6. Maintenance platform. DETAILED DESCRIPTION

[0021] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0023] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0024] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0027] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0028] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "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, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0029] See also Figure 1 to Figure 6 The embodiment of the present application provides a filtering device for filtering kitchen waste slurry, and the filtering device 1 includes: a first screen 201, the first screen 201 has a plurality of first screen holes, and the first screen holes are used to filter the kitchen waste slurry to obtain a first filtrate; an overflow weir plate 210, which is arranged below the first screen 201 and is used to receive the first filtrate, and an outlet weir is arranged on the overflow weir plate 210; a second screen 301, which is arranged below the overflow weir plate 210, and the mesh surface of the second screen 301 is a single curved surface, and the straight edge on one side of the single curved surface is aligned with the outlet weir, and is used to receive the first filtrate overflowing from the outlet weir; the second screen 301 has a plurality of second screen holes, and the area of ​​the second screen holes is smaller than the area of ​​the first screen holes, and the second screen holes are used to filter the first filtrate when the first filtrate flows along the arc direction of the single curved surface.

[0030] The feed water distribution assembly includes a feed pipe 101, a feed distribution trough 102, an overflow weir trough 103, a support angle steel 104, a water retaining plate 105, and a flushing water retaining plate 106. The feed pipe 101 passes through the feed port of the first screen 201, and the kitchen waste slurry enters the first screen 201 through the feed pipe 101. The end of the feed pipe 101 is connected to the square feed distribution trough 102. Overflow weir troughs 103 are arranged on both sides of the feed distribution trough 102. The overflow weir trough 103 can be arranged horizontally to evenly overflow the kitchen waste slurry at its outlet weir, so that the kitchen waste slurry is evenly spread on the screen surface of the first screen 201.

[0031] The feed pipe 101 and the feed distribution trough 102 can be welded into one. Preferably, the insertion depth of the feed pipe 101 is 1 / 3 to 1 / 2 of the length of the first screen 201. Since the insertion into the first screen 201 is deep, the feed distribution trough 102 can be fixed on the crossbeam 502 by the support angle steel 104. In addition, the use of the support angle steel 104 as a support component can prevent the debris (first solid impurities) screened out during the rotation of the first screen 201 from accumulating on the support component, and prevent the material from corroding the support component and the material from being corrupted; further, the water baffle 105 is provided to prevent the feed from returning out of the first screen 201 under the flushing of the flushing nozzle 403.

[0032] The upper filtering assembly includes a first screen 201, a spiral blade 202, a drum front supporting roller 203, a drum limiting ring 204, a driving reduction motor 205, a large gear 206, a small gear 207, a driving chain 208, a discharge port 209, an overflow weir plate 210, a gear water retaining plate 211, and a drum rear supporting roller 212.

[0033] The kitchen waste slurry overflowing from the overflow weir trough 103 is evenly spread on the first screen 201 rotating at a slow and uniform speed, and the materials smaller than the first sieve hole size pass through the first sieve hole and fall into the second screen 301. The materials larger than the first sieve hole size are retained in the first screen 201. The first screen 201 is cylindrical and forms a drum under the drive of the driving component. The first screen 201 is evenly distributed with first sieve holes around the circumference. The first sieve holes are in the form of wedge-shaped meshes. The wedge-shaped meshes have long sides and short sides. The short sides of the wedge-shaped meshes are called grating gaps, and the grating gaps are generally 3 to 5 mm. The grating gaps of the first sieve holes of the first screen 201 are larger than the grating gaps of the second sieve holes of the second screen 301. By combining the two sieve holes of the first sieve hole of the first screen 201 and the second sieve hole of the second screen 301, the screen blocking time can be greatly extended to achieve fine filtration of the kitchen waste slurry.

[0034] The end surface of the first screen 201 is welded and fixed with a large gear 206, which is connected to a small gear 207 through a driving chain. The small gear 207 drives the reduction motor 205 to rotate, thereby driving the large gear 206 and the first screen 201 to rotate. The driving reduction motor 205 is a variable frequency motor, and the speed of the first screen 201 is slow, with a speed of 4-10rpm, which can be adjusted according to the content of debris in the kitchen waste slurry. The faster the speed, the faster the speed of removing debris.

[0035] The spiral blade 202 is welded and fixed tightly against the inner side of the first screen 201. The spiral blade 202 can be continuous or discontinuous. When the first screen 201 rotates, the first solid impurities are thrown up or knocked down, and the spiral blade 202 cooperates to smoothly discharge the fallen first solid impurities from the first screen 201 into the discharge port 209. The pitch of the spiral blade 202 can be set to gradually increase along the discharge direction, so as to quickly discharge the first solid impurities from the discharge port 209.

[0036] The first screen 201 is supported by rollers, which include two groups of front roller support rollers 203 and rear roller support rollers 212. The rollers cooperate with the roller limit ring 204 to ensure the stability of the position of the first screen 201. The angle α between the central axis of the first screen 201 and the horizontal plane is 0-10°. If there is no requirement for the moisture content of the impurities, the angle α can be set to 0°; when the angle α increases, the probability of short-flow of raw materials can be reduced, and the residence time of impurities in the drum screen can be increased to reduce the moisture content of the impurities.

[0037] A gear water baffle 211 is provided on one side of the drum limiting ring 204 close to the first screen 201 to prevent the slurry from contaminating the gears, extend the life of the large gear 206, the small gear 207 and the driving chain, and avoid leakage of the filtering device 1.

[0038] The first filtrate overflows through the overflow weir plate 210 and enters the lower filter assembly, which includes a second screen 301, a filtrate receiving trough 302, a material receiving trough 303, a filtrate outlet 304 below the screen, a material outlet 305 above the screen, and a second filter hole 306. The width of the overflow weir plate 210 is consistent with the width of the second screen 301. The overflow weir plate 210 is adjusted to a horizontal state through the bolts and nuts of the base, so that the first filtrate is evenly spread on the uppermost end of the entire second screen 301, ensuring that materials pass through every part of the second screen 301, and making full use of the filtering area of ​​the arc-shaped single-curved screen.

[0039] The second screen 301 can separate the second filtrate and the second solid impurities (long fibers, plastics and other debris) in the first filtrate by gravity. The second screen 301 is in the form of a wedge-shaped mesh, and the wedge-shaped mesh has a long side and a short side. The long side of the wedge-shaped mesh is set perpendicular to the gravity direction, so that the long side of the wedge-shaped mesh is perpendicular to the water flow direction, that is, when the general long debris flows with the water flow, the long side of the debris is parallel to the water flow direction, so that it is easier to intercept the long debris through the second screen hole. The short side of the wedge-shaped mesh is called the grating gap, and the grating gap is ≤1mm according to the water inlet requirements of the membrane system. The side curve of the second screen 301 is preferably close to the arc of the maximum speed curve (the curve speed between two points is faster than the straight line speed), so as to ensure a faster water flow speed, which is convenient for washing the debris on the screen surface of the second screen 301 into the material receiving trough 303, and the second filtrate enters the material receiving trough 303. The filtrate receiving trough 302 and the material receiving trough 303 are respectively provided with an under-sieve filtrate outlet 304 and an over-sieve material outlet 305 .

[0040] Optionally, the first screen 201 and the second screen 301 can be cleaned by a scraper or a brush, however, the brush needs to be replaced regularly, the scraper inside the screen cannot scrape out the fibers, and the debris can easily and quickly block the screen. Therefore, the filtering efficiency of the filtering device 1 needs to be improved.

[0041] Based on this, the first screen 201 and the second screen 301 can be cleaned by flushing, and the second filtrate in the filtrate receiving trough 302 can be used as a water source to flush the first screen 201 and the second screen 301, so as to save resources and filter the second filtrate again, thereby improving the filtering effect.

[0042] The screen flushing assembly includes a flushing pump 401 , a flushing pipe 402 , a flushing nozzle 403 , a flushing spray gun 404 , and a solenoid valve 405 .

[0043] As the material is continuously filtered, it is inevitable that debris will adhere to the surface of the screen and clog the screen. Therefore, a flushing pump 401 can be set and fixed on the back of the filtrate receiving trough 302, and the second filtrate can be taken as the flushing water source, which greatly reduces the consumption of tap water and does not increase the amount of filtrate. The flushing water is transported to the flushing nozzle 403 and the flushing spray gun 404 through the flushing pipe 402, and the flushing frequency and flushing time of the flushing nozzle 403 can be controlled by the solenoid valve 405. The flushing nozzle 403 backwashes the first screen 201. The nozzle of the flushing nozzle 403 is attached to the flushing pipe 402 and fixed on the oblique upper side of the first screen 201. The number of the flushing nozzles 403 is determined according to the length of the first screen 201, so that the backwashing water can cover the entire screen. Generally, the interval is 300~600mm. The nozzle adopts a spiral nozzle, which is suitable for flushing water containing certain impurities. As the first screen 201 rotates, the debris attached to the first screen hole of the first screen 201 can be cleaned and discharged to the discharge port 209 along with the spiral blade 202. The backwashing process can be performed when the first screen 201 rotates or stops feeding, without affecting the filtering process.

[0044] A flushing water baffle 106 is arranged inside the first screen 201 near the discharge port 209. The flushing water baffle 106 is fixed on the feed distribution trough 102 to prevent backwash water from being directly sprayed onto the discharged debris, thereby improving the dryness of the discharged debris.

[0045] The flushing spray gun 404 performs positive flushing on the second screen 301, and the flushing spray gun 404 interface is arranged above the second screen 301. The curved screen is also manually cleaned regularly according to the blockage of the screen surface, generally after the filter device 1 is shut down, to prevent the organic solids from drying and blocking the screen surface.

[0046] The outer shell of the filter device 1 is provided with adjustable legs 501, a crossbeam 502, an equipment sealing shell 503, a quick-opening inspection port 504, a quick-opening observation port 505, a quick-opening door 506, and a deodorizing port 507. The adjustable legs 501 and the crossbeam 502 serve as supporting structural members for the outer shell and the internal screen, and also as supporting structural members for the inspection platform 6. In order to facilitate the inspection and maintenance and the replacement of the screen, the top cover of the upper filter assembly is fixed with rivets, and a rib seal is provided at the joint to prevent the slurry from seeping out. The lower second screen 301 can be opened and replaced through the side-opening quick-opening door 506, and the sealing part and the joint of the quick-opening door 506 are both provided with a rib seal to prevent the slurry from seeping out.

[0047] A quick-open observation port 505 or a quick-open inspection port 504 is provided above the discharge port 209 of the first screen 201 and above the flushing nozzle 403. A DN100 deodorizing port 507 is provided on the top cover of the first screen 201 to prevent odor from escaping. The housings of the movable parts such as the supporting roller, driving chain, and pinion are all riveted assembly types and can be quickly disassembled for easy maintenance.

[0048] The maintenance platform 6 is composed of a maintenance platform and a ladder, with adjustable legs 501 and a crossbeam 502 as supporting structures. The maintenance platform 6 is arranged on both sides of the upper filter assembly, which is convenient for observing the filtering and clogging of the first screen 201, observing the backwashing situation, and facilitating the repair and maintenance of the internal parts of the filter device 1.

[0049] The present application adopts an integrated device composed of two forms of screens, upper and lower, to finely filter the long fibers, plastics and other debris in the kitchen waste slurry to meet the feeding requirements of the membrane system in the carbon source preparation device. The kitchen waste slurry is first filtered through the drum-type first screen 201 with larger screen holes. The larger first screen hole can obtain higher flux and longer blocking time. At the same time, the first screen 201 rotates slowly to throw or knock down the debris adhering to the mesh, and the spiral blade 202 inside the first screen 201 is used to discharge the debris in time, which also prolongs the blocking time. The solid content of the filtrate after the upper filter assembly is removed is reduced, which creates good conditions for the subsequent arc-shaped second screen 301 with higher filtering accuracy. The first filtrate that has been initially removed by the drum-type first screen 201 enters the second screen 301. The second screen 301 uses the principle of the fastest curve (the speed of the object moving on the fastest curve between two points under the action of gravity is the fastest), and the fast-flowing fluid flushes the debris retained in the second screen 301 to the material receiving trough 303. The feed size, solid matter and debris content, and viscosity of the upper and lower screens are different. The two screens combine their own principles to play their best role and complement each other, avoiding the problem that the single first screen 201 is easily blocked, the single second screen 301 is viscous and difficult to flush, and the first filtrate on the second screen 301 has poor fluidity, thereby avoiding the problem of being unable to operate continuously and stably. Specifically, the coarse screen hole gap of the first screen hole is 3~5mm, and the fine screen hole gap of the second screen hole is ≤1mm. The combined filtration can make the kitchen waste slurry with high viscosity and many long fiber plastic debris meet the water inlet requirements of the membrane system. The filtering device 1 has the advantages of high filtration accuracy, the screen is not easy to be blocked, the processing capacity is large, and it can be continuously and stably operated for a long time. It can be used for the impurity removal pretreatment of slurry generated by various kitchen waste equipment (such as a three-phase oil extractor) to meet the impurity removal filtration under different slurry solid content, debris content, and different viscosity. The impurities of the filtrate particles under the screen of the second screen 301 are small in size and less in debris. It is used as a backwash water source to automatically clean the first screen 201 and the second screen 301 regularly, which greatly prolongs the screen plugging time. Basically, no manual cleaning is required. Backwashing can be performed during the filtration process, which also increases the processing capacity of the equipment and truly achieves continuous and stable operation. The energy consumption and screen wear of the low-speed rotating first screen 201 and the gravity-driven second screen 301 are lower than those of the high-speed centrifugal filtration method. There is no need to frequently replace consumable parts, no external tap water flushing, and basically no manual cleaning is required. Overall, the operating cost of the equipment is very low. The overflow weir plate 210 is a key component that connects the upper and lower parts, and the two types of filter screens are cleverly combined together, with a high degree of equipment intensiveness and a small footprint.

[0050] The slurry generated during the pretreatment of kitchen waste includes hopper and equipment (mainly spiral) drainage, solid-liquid separation slurry and slurry separated by three-phase oil extraction. The filtering device 1 can process various types of slurries in the kitchen waste pretreatment process. The slurry is pumped to the water inlet pipe and overflows from the water inlet pipe to the feed distribution trough 102. The area of ​​the feed distribution trough 102 is larger than the horizontal projection area of ​​the water inlet pipe, so the water flow rate of the water can be reduced, so that the water flow slowly overflows from the overflow weir troughs 103 on both sides of the feed distribution trough 102, and the slurry is evenly spread on the first screen 201.

[0051] The first screen 201 uses a wedge-shaped mesh with a mesh gap of 3 to 5 mm. When dealing with hopper and equipment drainage, since there are many and large debris, the mesh gap is set to 5 mm, and the area of ​​the first screen 201 needs to be appropriately enlarged; when dealing with slurry after three-phase oil extraction, the debris in the material has been pre-treated and the debris content is relatively small, and the mesh gap can be selected to be 3 mm. Compared with circular mesh, the wedge-shaped mesh has a higher opening rate, better structural strength and lower production cost.

[0052] The first screen 201 drives the small gear 207 by driving the reduction motor 205, and the small gear 207 drives the large gear 206 through the driving chain 208. The large gear 206 is fixed to the first screen 201 by bolt welding, thereby driving the first screen 201 in turn.

[0053] The speed of the first screen 201 is 4-10rpm, which can be adjusted by a variable frequency motor. After the raw material enters the first screen 201, the material smaller than the first screen hole size falls into the overflow weir plate 210, and the debris on the screen is thrown up and dropped by the rotation of the first screen 201. The debris is discharged to the discharge port along with the spiral blades 202 welded to the inner wall of the drum of the first screen 201, completing the upper filtering process.

[0054] When dealing with hoppers and equipment draining with high debris and solid content, the first screen 201 rotates at a speed of 8-10rpm, which can increase the debris conveying capacity and discharge the debris from the first screen 201 more quickly. The higher speed will reduce the dryness of the debris. When dealing with three-phase oil extraction slurry with less debris and solid content, the first screen 201 rotates at a lower speed of 4-6rpm. The lower the speed, the lower the energy consumption of the equipment. Due to the lower speed of the first screen 201, the moisture content of the debris is between 85% and 90%. The debris still contains a high organic matter, which can be processed in the anaerobic digestion system or in the extrusion equipment to further increase the dryness.

[0055] When the discharged impurity material requires a higher dryness, the first screen 201 can be set to be inclined, that is, the feed port is lower than the discharge port 209. For example, the angle between the central axis of the first screen 201 and the horizontal plane is set to 10°, which reduces the probability of material short-flow and prolongs the residence time of the material in the first screen 201, so that the moisture content of the discharged impurity material is between 83% and 88%.

[0056] The first filtrate that has completed the upper filtration is temporarily stored in the overflow weir plate 210. The width of the overflow weir plate 210 is the width of the first screen 201. The outer shell of the filtering device 1 is used as the outer shell of the overflow weir plate 210. The horizontality of the outlet weir of the overflow weir plate 210 is strictly controlled by adjusting the height of the bolts and nuts of the base of the adjustable support leg 501, so that the first filtrate is evenly spread on the entire second screen 301.

[0057] The second screen 301 is a wedge-shaped screen with a mesh gap of 1 mm. The long side of the wedge-shaped mesh is perpendicular to the water flow direction, which can remove most of the long fibers and plastic debris, and obtain a filtrate that meets the water inlet requirements of the membrane system. The curvature of the second screen 301 is preferably close to the maximum speed curve, which can form the fastest water flow speed to flush the debris on the screen surface to the material receiving trough 303, and discharge the equipment through the outlet of the material receiving trough 303. During operation, adjusting the appropriate raw material flow is an important condition to ensure the flushing speed and flushing effect.

[0058] During the debugging and operation process, it is necessary to use the maintenance platform 6, the quick-open observation port 505 and the quick-open door 506 to observe the blockage and impurity situation of the mesh of the first screen 201 and the second screen 301, determine the appropriate rotation speed, backwashing time and backwashing frequency of the first screen 201, and control the flushing frequency and flushing time through the solenoid valve. The equipment can be backwashed online without stopping to prevent the mesh of the first screen 201 and the second screen 301 from being blocked to the point where normal filtering cannot be performed, thereby ensuring the long-term continuous and stable operation of the filtering device 1.

[0059] The screen flushing assembly includes a flushing pump 401, a flushing pipe 402, a flushing nozzle 403, a flushing spray gun 404 and a solenoid valve 405. The flushing pump 401 uses the second filtrate as the flushing water source, and transports it to the flushing nozzle 403 through the flushing pipe 402. The nozzle uses a spiral nozzle, which has a larger flow channel and better impurity resistance. The coverage radius of a single nozzle is about 300mm, and the number of nozzles should be able to cover all the screens. The flow rate of a single nozzle is 15~20L / min. Since no external tap water is introduced, the nozzle flushing flow rate can be appropriately increased to enhance the flushing effect.

[0060] When the equipment stops feeding, the flushing nozzle can be used to continue flushing for 3 to 5 minutes, and the flushing spray gun 404 can be used to flush the second screen 301 from the front to prevent the organic solids from drying and hardening and blocking the screen surface.

[0061] When the filtering device 1 is in operation, the operation of the equipment can be checked through the maintenance platform 600 and the quick-opening observation port 50, the quick-opening maintenance port 504, and the quick-opening door 056. When the filtering device 1 needs maintenance or the screen is replaced, the first screen 201 can be replaced as a whole through the quick-opening door 506, and the first screen 201 can be replaced as a whole by quickly removing the top cover, and the process is fast and simple.

[0062] A deodorizing port 507 is provided on the side of the filtering device 1. The deodorizing fan is turned on before the machine is started and the material is fed. With the good sealing performance of the device, no odor can escape from the device.

[0063] In actual use, the kitchen waste slurry can be processed as follows: the gap of the drum screen is 3.5mm, the gap of the first screen 201 is 1mm, the drum speed of the first screen 201 is 6rpm, the inclination angle of the first screen 201 is 4°, the backwashing frequency is 4h / time, and the flushing time is 3min. Most of the long fibers and plastic debris in the kitchen waste slurry can be removed, and the size of the materials entering the membrane system is ≤1mm, so that the operation of the filter device 1 is stable and there is no clogging of the sieve holes. By comparing the operation, it is found that when this filter device 1 is not used, the membrane system only filters the debris through the self-cleaning filter configured by itself. After only 8 hours of operation, the screen of the self-cleaning filter is blocked and the raw materials cannot be fed into the membrane. After using this device, the membrane system has not experienced the blockage of the self-cleaning filter mesh, membrane hole and membrane end face, and the system runs smoothly. After 3 months of operation, the membrane device was disassembled and it was found that only a very small amount of long debris was attached to the membrane end face, which greatly increased the stable operation time of the membrane system.

[0064] In the embodiment of the present application, solid impurities with larger volume in the kitchen waste slurry are filtered through the first filter holes of the first screen 201 to obtain a first filtrate, and then long debris with smaller volume in the first filtrate is filtered through the second filter holes on the second screen 301 whose area is smaller than the first filter holes, so as to achieve fine filtration of the kitchen waste slurry through the layered arrangement of the first filter net and the second filter net, thereby improving the filtering effect of the kitchen waste slurry; by setting the mesh surface of the second screen 301 to be a single curved surface, when the first filtrate is filtered through the second screen 301, the first filtrate can flow naturally on the single curved surface under the action of gravity, so that when some of the second filter holes on the single curved surface are blocked, the first filtrate can still flow along the arc direction of the single curved surface under the action of gravity. The first filtrate overflowing from the outlet weir can be spread more evenly to the second screen 301 to make full use of the filtration area of ​​the second screen 301, and the first filtrate can flow from the straight edge on one side of the single curved surface to the straight edge on the other side to extend the flow path of the first filtrate on the single curved surface, thereby improving the utilization rate of the second filter holes on the second screen 301 and making full use of the filtration area of ​​the second screen 301.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A filtering device for filtering kitchen waste slurry, characterized in that: The filtering device comprises: A first screen, wherein the first screen has a plurality of first screen holes, and the first screen holes are used to filter the kitchen waste slurry to obtain a first filtrate; An overflow weir plate is disposed below the first screen and is used to receive the first filtrate. An outlet weir is disposed on the overflow weir plate; A second screen is arranged below the overflow weir plate, the mesh surface of the second screen is a single curved surface, a straight line edge on one side of the single curved surface is aligned with the outlet weir, and is used to receive the first filtrate overflowing from the outlet weir; The second screen has a plurality of second screen holes, the area of ​​the second screen holes is smaller than the area of ​​the first screen holes, and the second screen holes are used to filter the first filtrate when the first filtrate flows along the arc direction of the single curved surface.

2. The filtering device according to claim 1, characterized in that The first screen and the second screen are both wedge-shaped screens, and the long sides of the second screen holes are perpendicular to the direction of gravity.

3. The filtering device according to claim 1, characterized in that The arc of the single curved surface is in the shape of a maximum speed curve.

4. The filtering device according to claim 1, characterized in that The filtering device also includes a drive assembly; The first screen is cylindrical and connected to the driving assembly, and is used to rotate under the drive of the driving assembly to filter out first solid impurities in the kitchen waste slurry to obtain a first filtrate; One end of the first screen is provided with a feed port, and the other end is provided with a discharge port, the feed port is used to input the kitchen waste slurry, and the discharge port is used to output the first solid impurities; A spiral blade is provided in the first screen. The spiral blade takes the central axis of the cylinder as the blade axis and is distributed on the inner wall of the first screen to transport the first solid impurities to the discharge port.

5. The filtering device according to claim 4, characterized in that The pitch of the portion of the spiral blade close to the discharge port is greater than the pitch of the portion of the spiral blade close to the feed port.

6. The filtering device according to claim 4, characterized in that An angle is formed between the central axis of the first screen and the horizontal plane, the angle ranges from 0 to 10 degrees, and the discharge port is higher than the feed port.

7. The filtering device according to claim 4, characterized in that The second screen is used to filter out second solid impurities in the first filtrate to obtain a second filtrate; The filtering equipment also includes a filtrate receiving trough and a material receiving trough. The filtrate receiving trough is aligned with the second screen and is arranged below the second screen to receive the second filtrate. The material receiving trough is close to the straight edge on the other side of the second screen and is used to collect second solid impurities that slide off the second screen.

8. The filtering device according to claim 7, characterized in that The filtering device also includes: A plurality of flushing nozzles are distributed along the central axis of the first screen and fixed at the upper oblique side of the first screen; The flushing spray gun is arranged above the side of the second screen.

9. The filtering device according to claim 8, characterized in that The filtering device further comprises a water baffle, and the water baffle is arranged close to the feed inlet.

10. The filtering device according to claim 8, characterized in that The filtering device also includes: A water inlet pipe connected to the filtrate receiving tank; A plurality of water outlet pipes are respectively connected to the flushing spray gun and the plurality of flushing nozzles; The solenoid valve is connected to the water inlet pipe and is used to extract the second filtrate in the filtrate receiving tank and transport the extracted second filtrate to the multiple water outlet pipes.

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