Vacuum drum filter for waste diatomite

Abstract

The invention discloses a vacuum drum filter for waste diatomite, which belongs to the technical field of separation and filtration, and is characterized in that a negative pressure roller consistent with the transmission speed of a drum is additionally arranged, so that filter cloth replaces a traditional circumferential fixed coating mode in an advancing transmission mode, and the filter cloth is separated from the surface of the drum at the moment of changing the advancing direction. Under the action of tension change and centrifugal force generated by bending of the filter cloth, a filter cake which is easily adhered to the filter cloth is actively stripped, a pre-coating mechanism matched with the negative-pressure rotating roller is established, pre-coating slurry is sprayed to the conveyed filter cloth, the outer surface of the filter cloth is ensured to be uniformly stacked layer by layer under the assistance of vacuum, and a temporary filter cake with an open pore structure is formed; according to the present invention, the waste diatomite is used as the main filtration material in the subsequent filtration stage so as to prevent the small waste diatomite particles from penetrating through the filter cloth, and based on the pre-coating-filtration-cleaning dynamic closed-loop deep filtration mechanism, the filtration effect is improved, and the protection effect on the filter cloth is provided.

Description

Technical Field

[0001] This invention relates to the field of separation and filtration technology, and more specifically, to a waste diatomaceous earth vacuum drum filter. Background Technology

[0002] Diatomaceous earth plays a crucial role in the beer industry. Its core use is as a filtration aid in the "clarification filtration" stage of beer production. Its main goal is to efficiently and economically remove yeast, protein coagulation, hop residue, colloids, and other tiny suspended particles from beer, resulting in a clear, attractive, flavorful, and long-lasting finished beer.

[0003] Diatomaceous earth is used extensively in the beer industry, and the efficient treatment of the waste diatomaceous earth generated from it (such as using a vacuum drum filter) has become an important part of the industrial chain. Vacuum drum filters are used for filtration and separation, as disclosed in patents CN208553337U and CN111085046B.

[0004] Currently, the drum is immersed in the waste diatomaceous earth slurry in the feed tank. The inside of the drum is divided into multiple fan-shaped filter chambers. Each filter chamber is connected to the distribution head through a pipe. Under vacuum, the filtrate penetrates the filter medium (filter cloth) covering the surface of the drum and enters the filter chamber. The filtrate carrying air is sucked into the vacuum separation tank through the distribution head pipe to separate the filtrate from the air. Tiny impurity particles in the waste diatomaceous earth can easily penetrate the filter cloth, resulting in fine impurities often remaining in the filtrate, making it difficult to achieve more efficient separation and limiting the filtrate clarification effect. In addition, the filter cloth on conventional drum filters is tightly attached to the outer surface of the drum. For waste diatomaceous earth with high water content and strong viscosity, the adhered filter cake is not easy to peel off. Summary of the Invention

[0005] The purpose of this invention is to solve existing practical problems and provide a waste diatomaceous earth vacuum drum filter compared with existing technologies.

[0006] The objective of this invention can be achieved through the following technical solution: a waste diatomaceous earth vacuum drum filter, comprising a treatment tank and a slurry tank installed inside it in a lifting manner, a drum located above the slurry tank is installed on the treatment tank, a support base is fixed on one side of the slurry tank, a negative pressure rotating roller is rotatably installed on the support base through a positioning frame, a filter cloth is installed in linkage between the drum and the negative pressure rotating roller, the filter cloth is inclined downward from the upper part of the drum to the upper part of the negative pressure rotating roller to form an upper conveying surface, and inclined downward from the lower part of the negative pressure rotating roller to the lower part of the drum to form a lower conveying surface;

[0007] The support base is fixedly installed with a coating box located above the negative pressure rotating roller and used for the flow of pre-coated slurry. The bottom end of the coating box has a coating slit facing the conveying surface of the filter cloth. Multiple vacuum adsorption holes are opened on the outer peripheral wall of the negative pressure rotating roller. One end of the negative pressure rotating roller is connected to a vacuum pump through a rotary joint and a negative pressure pipe. The positioning frame is provided with a sealing ring plate that fits and covers the outer end wall of the negative pressure rotating roller on the side away from the filter cloth conveying section.

[0008] The coating box is provided with a scraping assembly that acts on the upper end of the conveying surface on the filter cloth, and the scraping assembly is installed at an angle downward from one side of the conveying surface on the filter cloth to the other side.

[0009] Furthermore, a slurry storage tank for loading pre-coated slurry is also installed at the rear end of the support base. The slurry storage tank is connected to a pressure stabilizing buffer tank, and the outlet end of the pressure stabilizing buffer tank is connected to the coating box through a pipe.

[0010] Furthermore, the support base is provided with a rinsing liquid collection tank and a pre-coated slurry collection tank from the inside to the outside. The pre-coated slurry collection tank is located below the part of the filter cloth that is driven by the negative pressure roller. A rinsing pipe is provided above the rinsing liquid collection tank and located above the lower conveying surface of the filter cloth.

[0011] Furthermore, the slag scraping assembly includes a silicone scraper that is flush with the conveying surface on the filter cloth, with a 2mm gap between the silicone scraper and the conveying surface on the filter cloth, and a slag discharge groove that matches the upper surface of the silicone scraper at its rear end.

[0012] Furthermore, the slag discharge trough and the inclined lower end of the silicone scraper extend to the outside of the filter cloth and are fixedly installed with a hopper, and the discharge port at the bottom of the hopper is provided with a filter slag conveying assembly.

[0013] Furthermore, the filter residue conveying assembly includes a horizontal conveyor connected to the discharge port at the bottom of the hopper, and the discharge port of the horizontal conveyor is provided with an inclined conveyor that is inclined upward.

[0014] Furthermore, the treatment tank is equipped with a slag loosening assembly located between the rotating drum and the slag scraping assembly and acting on the lower end of the conveying surface on the filter cloth. The assembly includes a vibrating plate attached to the lower end of the conveying surface on the filter cloth. A slot is opened on the upper side wall of the lower side of the vibrating plate. An air passage is opened inside the slot. A plurality of air jet holes connected to the air passage are opened on the upper end wall of the slot. An air supply pipe is connected to the outside of the air passage.

[0015] This invention also proposes a method for using a waste diatomaceous earth vacuum drum filter, comprising the following steps:

[0016] Step 1, Pre-coating stage: Using the linkage structure of slurry storage tank, pressure stabilizing buffer tank and coating box, the pre-coating slurry is evenly coated onto the conveyed filter cloth. With the vacuum assistance of negative pressure rotating roller, diatomaceous earth particles are trapped on the surface of the filter cloth. After multiple cycles of pre-coating, the layers are piled up until the outer surface of the filter cloth reaches the required pre-coating thickness of 2-3 mm.

[0017] Step 2, Filtration stage: Stop the pre-coating operation, raise the slurry tank upwards to ensure that the filter cloth area at the bottom of the drum can be immersed in the waste diatomaceous earth slurry to be filtered. The drum rotates at the normal filtration speed. The part submerged in the slurry tank continues to form a filter cake, while the part above the liquid surface undergoes filter cake dewatering.

[0018] When the drum rotates to the slag scraping assembly, the filter cake is scraped off using a silicone scraper, and the scraped filter cake is discharged laterally outward through the inclined slag discharge trough.

[0019] Step 3, rinsing stage: After filtering for a period of time, the pre-coating layer is gradually exhausted. At this time, adjust the distance between the silicone scraper and the filter cloth and scrape it off uniformly. Before scraping, use a vibrating plate to ultrasonically vibrate and pneumatically loosen the filter cake. Then use a rinsing pipe to rinse the filter cloth in the reverse direction to remove residual impurities.

[0020] Step 4: Repeat the pre-coating process from Step 1, and repeat the process.

[0021] Compared with the prior art, the advantages of this invention are:

[0022] 1. This solution adds a negative pressure rotating roller with the same speed as the drum drive, allowing the filter cloth to replace the traditional fixed circumferential wrapping mode with a traveling transmission mode. At the moment the filter cloth leaves the drum surface and changes direction, the tension change and centrifugal force caused by the bending of the filter cloth make it easy for the filter cake to actively peel off. A pre-coating mechanism adapted to the negative pressure rotating roller is established. A coating box for the flow of pre-coated slurry is added above the negative pressure rotating roller. The pre-coated slurry is coated onto the conveyed filter cloth. With vacuum assistance, it is ensured that the outer surface of the filter cloth is uniformly and layer by layer, forming a temporary filter cake with an open pore structure, which becomes the main "filter material" for subsequent filtration. This prevents smaller waste diatomaceous earth particles (as well as subsequent filter aids and solids to be filtered) from penetrating into the filter cloth, thereby improving the filtration effect.

[0023] 2. Based on the above, a combination structure of scraping and loosening components is set in the vertical direction of the conveying surface on the filter cloth. The scraping component continuously acts on the filtration stage, using an inclined silicone scraper to scrape off the filter cake attached to the pre-coating layer. The cake residue is transported laterally outward by an inclined discharge trough, which does not affect the spatial arrangement of the pre-coated structure and facilitates the collection of cake residue. In the filter layer cleaning and rinsing stage, the vibrating plate works together with the scraping component and the rinsing pipe. Before the filter cake is scraped off, the vibrating plate is used to ultrasonically vibrate and pneumatically loosen the filter cake on the filter cloth, and the scraping height of the scraping component is lowered. Waste diatomaceous earth and consumed new diatomaceous earth are removed as filter cake. Then, the filter cloth is rinsed in reverse depth using the rinsing pipe. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the external structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the external structure from another perspective of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the filter cloth linked between the rotating drum and the negative pressure roller of the present invention;

[0027] Figure 4 This is a schematic diagram of the structure at the junction of the negative pressure roller and the positioning frame of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the negative pressure roller and the positioning frame when they are separated.

[0029] Figure 6 This is a schematic diagram of the slag scraping assembly of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of the slag loosening component of the present invention;

[0031] Figure 8 This is a cross-sectional schematic diagram of the present invention during operation.

[0032] Explanation of the labels in the diagram:

[0033] 1. Rotary drum; 2. Filter cloth; 3. Slurry tank; 4. Positioning frame; 401. Sealing ring plate; 5. Negative pressure roller; 501. Vacuum adsorption hole; 6. Slurry storage tank; 7. Pressure stabilizing buffer tank; 8. Coating box; 9. Slag scraping assembly; 91. Silicone scraper; 92. Slag discharge trough;

[0034] 10. Hopper; 11. Horizontal conveyor; 12. Inclined conveyor; 13. Vibrating plate; 131. Groove; 132. Air jet; 14. Flushing pipe. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Example 1: This invention discloses a waste diatomaceous earth vacuum drum filter. Please refer to [link / reference]. Figures 1-3 It includes a treatment tank and a slurry tank 3 that is lifted and installed in the treatment tank. A rotating drum 1 is installed on the treatment tank above the slurry tank 3. A support base is fixed on one side of the slurry tank 3. A negative pressure rotating roller 5 is rotatably installed on the support base through a positioning frame 4.

[0037] A filter cloth 2 is installed in conjunction with the drum 1 and the negative pressure roller 5. The outer diameter of the negative pressure roller 5 is smaller than the outer diameter of the drum 1. The filter cloth 2 is pulled downward from the upper part of the drum 1 to the upper part of the negative pressure roller 5 to form an upper conveying surface, and is pulled downward from the lower part of the negative pressure roller 5 to the lower part of the drum 1 to form a lower conveying surface.

[0038] The slurry tank 3 is filled with waste diatomaceous earth slurry to be filtered. Under the suction of the vacuum pump, the speed reducer drives the drum 1 to rotate, thereby creating a uniform vacuum on the surface of the drum 1 to draw in the waste diatomaceous earth slurry. After passing through the filter cloth 2 on the drum 1, the waste diatomaceous earth slurry is drawn into the drum 1 together with the airflow generated when the vacuum is formed. The solid particles in the waste diatomaceous earth slurry are adsorbed on the filter cloth 2. The filtrate eventually flows into a separate collection container and is finally pumped into a vacuum separation tank for subsequent separation treatment. The specific principle is existing technology and will not be elaborated in detail here.

[0039] A negative pressure roller 5 with the same transmission speed as the drum 1 is added, so that the filter cloth replaces the traditional circumferential fixed wrapping mode with a traveling transmission mode. At the moment when the filter cloth leaves the surface of the drum and changes its direction of travel, the filter cake that is attached to it is easily peeled off due to the tension change and centrifugal force generated on the curved surface of the filter cloth.

[0040] Please see Figure 1 , Figure 2 as well as Figure 6A scraping assembly 9 is provided on the upper side of the coating box 8, which acts on the upper end of the conveying surface of the filter cloth 2. The scraping assembly 9 is installed inclined downward from one side of the conveying surface of the filter cloth 2 to the other side. The scraping assembly 9 includes a silicone scraper 91 that is flush with the conveying surface of the filter cloth 2. The rear end of the silicone scraper 91 is provided with a slag discharge groove 92 that is adapted to its upper end surface. The slag discharge groove 92 and the inclined lower end of the silicone scraper 91 extend to the outside of the filter cloth 2 and are fixedly installed with a hopper 10. The bottom outlet of the hopper 10 is provided with a filter slag conveying assembly. The filter slag conveying assembly includes a horizontal conveyor 11 that is connected to the bottom outlet of the hopper 10. The outlet of the horizontal conveyor 11 is provided with an inclined conveyor 12 that is inclined upward.

[0041] Please see Figure 1 , Figure 2 as well as Figure 7 The treatment tank is equipped with a slag loosening assembly located between the rotating drum 1 and the slag scraping assembly 9 and acting on the lower end of the conveying surface of the filter cloth 2. The slag loosening assembly includes a vibrating plate 13 attached to the lower end of the conveying surface of the filter cloth 2. A slot 131 is opened on the upper side wall of the lower side of the vibrating plate 13. An air passage is opened inside the slot 131. A plurality of air jet holes 132 connected to the air passage are opened on the upper wall of the slot 131. An air supply pipe is connected to the outside of the air passage.

[0042] A combination structure of a scraping assembly 9 and a vibrating plate 13 is arranged on the upper and lower directions of the conveying surface on the filter cloth 2. Before the filter cake is scraped off, the filter cake on the filter cloth 2 is subjected to ultrasonic vibration and pneumatic loosening by the vibrating plate 13, and the loosened filter cake is scraped off by the inclined silicone scraper 91. The cake residue is conveyed outward and discharged laterally by the inclined slag discharge trough 92, which does not affect the spatial arrangement of the pre-coated structure and facilitates the collection of cake residue.

[0043] Example 2: Based on Example 1, this example adds a pre-coating mechanism adapted to the negative pressure rotating roller 5 to perform a pre-coating process before formal filtration. Specifically:

[0044] Please see Figures 3-5 A coating box 8 is fixedly installed on the support base above the negative pressure rotating roller 5 and is used for the flow of pre-coated slurry. The bottom end of the coating box 8 is provided with a coating slit facing the conveying surface of the filter cloth 2. Multiple vacuum adsorption holes 501 are opened on the outer peripheral wall of the negative pressure rotating roller 5. One end of the negative pressure rotating roller 5 is connected to a vacuum pump through a rotary joint and a negative pressure pipe. The positioning frame 4 is provided with a sealing ring plate 401 that fits and covers the outer end wall of the negative pressure rotating roller 5 on the side away from the conveying section of the filter cloth 2. The setting of the sealing ring plate 401 helps the negative pressure rotating roller 5 to present a negative pressure sealing state, so that the end face of the side contacting the conveying section of the filter cloth 2 has an suction force from the outside to the inside.

[0045] The rear end of the support base is also equipped with a slurry storage tank 6 for loading the pre-coating slurry. The slurry storage tank 6 is connected to a pressure stabilizing buffer tank 7. The outlet end of the pressure stabilizing buffer tank 7 is connected to the coating box 8 through a pipe. The pre-coating slurry is made of fresh diatomaceous earth slurry. Fresh, unused diatomaceous earth is used during pre-coating and mixed with water (or other liquids) to form a slurry. The diatomaceous earth particles are fully dispersed and suspended in the slurry. They maintain their original size and structure (with porosity and a certain strength). The key to the successful pre-coating of the new diatomaceous earth lies in "bridging" and the rapid formation of the initial filter cake layer.

[0046] Please see Figure 8 The pre-coated slurry is applied to the conveyed filter cloth 2 through the coating slit at the bottom of the negative pressure rotating roller 5. With the vacuum assistance of the negative pressure rotating roller 5, the filter cloth 2 is uniformly and layer by layer deposited until the thickness reaches 2-3 mm, forming a temporary filter cake with an open pore structure, which becomes the main "filter material" for subsequent filtration. By temporarily constructing a peelable and replaceable microporous filter layer on the outside of the filter cloth 2, based on the dynamic depth filtration mechanism, it is also easy to continuously prevent fine particles and colloidal substances from directly contacting and clogging the filter cloth pores in the subsequent formal filtration stage, which not only improves the filtration effect, but also protects the filter cloth 2.

[0047] It should be noted that the scraping assembly 9 can be set to be adjustable up and down. In the initial stage, a 2mm gap is left between the silicone scraper 91 and the conveying surface of the filter cloth 2 to facilitate the formation of the pre-coating. In the subsequent filtration stage, the silicone scraper 91 only scrapes off the waste filter cake on the pre-coating. When the pre-coating is gradually exhausted, the gap between the silicone scraper 91 and the filter cloth 2 is adjusted to scrape off the pre-coating. During the non-cleaning stage of the filter cloth 2, the working mechanism of the vibration plate 13 is not activated to avoid the peeling off of the pre-coating.

[0048] In addition, a rinsing liquid collection tank and a pre-coated slurry collection tank are placed on the support from the inside to the outside. The pre-coated slurry collection tank is located below the part of the filter cloth 2 that is driven by the negative pressure roller 5. A rinsing pipe 14 is provided above the rinsing liquid collection tank and located above the lower conveying surface of the filter cloth 2.

[0049] During the coating process, the pre-coated slurry detached from the filter cloth 2 on the outer end face of the negative pressure rotating roller 5 is collected by the pre-coated slurry collection tank. The addition of the rinsing pipe 14 and the rinsing liquid collection tank is used to reverse rinse the inner surface of the filter cloth 2 during the rinsing stage, so as to remove fine particles, colloidal substances and organic residues embedded in the pores of the filter cloth 2, and restore its air permeability and filtration performance.

[0050] Example 3: As can be seen from Examples 1 and 2, the present invention also proposes a method for using a waste diatomaceous earth vacuum drum filter. Please refer to [link / reference needed]. Figure 8 This includes the following steps:

[0051] Step 1, Pre-coating stage: Using the linkage structure of slurry storage tank 6, pressure stabilizing buffer tank 7, and coating box 8, the pre-coating slurry is evenly coated onto the conveyed filter cloth 2. With the vacuum assistance of negative pressure rotating roller 5, the pre-coating slurry is adsorbed onto the filter cloth 2 as it rotates onto the negative pressure rotating roller 5. The vacuum suction removes the liquid from the slurry, and the diatomaceous earth particles are trapped on the surface of the filter cloth. After multiple cycles of pre-coating, the layers are accumulated one by one. Usually, the rotating drum 1 rotates at a relatively slow speed to ensure that the entire outer surface of the filter cloth 2 is evenly and fully pre-coated until the filter layer reaches the required pre-coating thickness of 2-3 mm.

[0052] During this process, the slurry tank 3 descends to its lowest point, and the filter cloth 2 does not come into contact with the waste diatomaceous earth slurry inside the slurry tank 3 during multiple cycles of pre-coating.

[0053] Step 2, Filtration stage: Stop the pre-coating operation, raise the slurry tank 3 upwards to ensure that the filter cloth 2 area at the bottom of the drum 1 can be immersed in the waste diatomaceous earth slurry to be filtered, and continue to add fine diatomaceous earth particles. The drum 1 rotates at the normal filtration speed. The part submerged in the slurry tank 3 continues to form a filter cake, while the part that leaves the liquid surface is dehydrated.

[0054] When the drum 1 rotates to the slag scraping assembly 9, the filter cake is scraped off by the silicone scraper 91, and the scraped filter cake is discharged laterally outward through the inclined slag discharge trough 92.

[0055] Step 3, Cleaning stage: After filtering for a period of time, the pre-coating layer is gradually depleted. At this time, adjust the distance between the silicone scraper 91 and the filter cloth 2 to uniformly scrape off the pre-coating layer. Before scraping, use the vibrating plate 13 to ultrasonically vibrate and pneumatically loosen the pre-coating layer and filter cake on the filter cloth 2. Waste diatomaceous earth and consumed new diatomaceous earth are used together as filter cake to remove. Then, use the rinsing pipe 14 to backwash the filter cloth 2 to remove residual impurities.

[0056] Step 4: Repeat the pre-coating process from Step 1, and repeat this cycle (the cycle is usually 8 to 24 hours).

[0057] In summary: The addition of a negative pressure rotating roller 5 with the same transmission speed as the rotating drum 1 allows the filter cloth to replace the traditional circumferential fixed wrapping mode with a traveling transmission mode. At the moment the filter cloth leaves the surface of the rotating drum and changes its direction of travel, the tension change and centrifugal force generated by the bending of the filter cloth make it easy for the filter cake to be actively peeled off. A pre-coating mechanism adapted to the negative pressure rotating roller 5 is established. A coating box 8 for the flow of pre-coated slurry is added above the negative pressure rotating roller 5. The pre-coated slurry is coated onto the conveyed filter cloth 2. With vacuum assistance, it is ensured that the outer surface of the filter cloth 2 is uniformly and layer by layer, forming a temporary filter cake with an open pore structure, which becomes the main "filter material" for subsequent filtration. This prevents smaller waste diatomaceous earth particles (as well as subsequent filter aids and solids to be filtered) from penetrating into the filter cloth. Based on the dynamic closed-loop depth filtration mechanism of "pre-coating-filtration-cleaning", the filtration effect is improved, and the filter cloth 2 is also protected.

[0058] A combination structure of a scraping assembly 9 and a vibrating plate 13 is set in the vertical direction of the conveying surface on the filter cloth 2. The scraping assembly 9 continuously acts on the filtration stage, and the filter cake attached to the pre-coating layer is scraped off by the inclined silicone scraper 91. The cake residue is discharged laterally outward by the inclined slag discharge trough 92, which does not affect the spatial arrangement of the pre-coated structure and facilitates the collection of cake residue. In the filter layer cleaning stage, the vibrating plate 13 works together with the scraping assembly 9 and the rinsing pipe 14. Before the filter cake is scraped off, the filter cake on the filter cloth 2 is ultrasonically vibrated and pneumatically loosened by the vibrating plate 13. Waste diatomaceous earth and consumed new diatomaceous earth are removed as filter cake. Then, the filter cloth 2 is rinsed in reverse by the rinsing pipe 14 to remove residual impurities.

[0059] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto; any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A vacuum drum filter for waste diatomaceous earth, comprising a treatment tank and a slurry tank (3) installed inside the tank and raised therein, wherein a drum (1) is installed above the slurry tank (3), characterized in that: A support base is fixed on one side of the slurry tank (3). A negative pressure roller (5) is rotatably installed on the support base via a positioning frame (4). A filter cloth (2) is installed between the drum (1) and the negative pressure roller (5). The filter cloth (2) is pulled downward from the upper part of the drum (1) to the upper part of the negative pressure roller (5) to form an upper conveying surface, and pulled downward from the lower part of the negative pressure roller (5) to the lower part of the drum (1) to form a lower conveying surface. The support base is fixedly installed with a coating box (8) located above the negative pressure rotating roller (5) and used for the flow of pre-coated slurry. The bottom end of the coating box (8) is provided with a coating slit facing the conveying surface of the filter cloth (2). Multiple vacuum adsorption holes (501) are opened on the outer peripheral wall of the negative pressure rotating roller (5). One end of the negative pressure rotating roller (5) is connected to a vacuum pump through a rotary joint and a negative pressure pipe. The positioning frame (4) is provided with a sealing ring plate (401) that fits and covers the outer end wall of the negative pressure rotating roller (5) on the side away from the conveying section of the filter cloth (2). The coating box (8) is provided with a scraping assembly (9) that acts on the upper end of the conveying surface on the filter cloth (2), and the scraping assembly (9) is installed inclined downward from one side of the conveying surface on the filter cloth (2) to the other side.

2. The waste diatomaceous earth vacuum drum filter according to claim 1, characterized in that: The rear end of the support base is also equipped with a slurry storage tank (6) for loading pre-coated slurry. The slurry storage tank (6) is connected to a pressure stabilizing buffer tank (7). The pressure stabilizing buffer tank (7) is connected to the coating box (8) through a pipe.

3. The vacuum drum filter for waste diatomaceous earth according to claim 2, characterized in that: The support base has a rinsing liquid collection tank and a pre-coated slurry collection tank placed from the inside to the outside. The pre-coated slurry collection tank is located below the negative pressure roller (5), and a rinsing pipe (14) is provided above the rinsing liquid collection tank, located above the lower conveying surface of the filter cloth (2).

4. The waste diatomaceous earth vacuum drum filter according to claim 1, characterized in that: The scraping assembly (9) includes a silicone scraper (91) flush with the conveying surface of the filter cloth (2), with a 2mm gap between the silicone scraper (91) and the conveying surface of the filter cloth (2), and a slag discharge groove (92) adapted to its upper end surface is provided at the rear end of the silicone scraper (91).

5. A vacuum drum filter for waste diatomaceous earth according to claim 4, characterized in that: The slag discharge trough (92) and the silicone scraper (91) extend at their inclined lower ends to the outside of the filter cloth (2) and are fixedly installed with a hopper (10). The discharge port at the bottom of the hopper (10) is provided with a filter slag conveying assembly.

6. The vacuum drum filter for waste diatomaceous earth according to claim 1, characterized in that: The filter residue conveying assembly includes a horizontal conveyor (11) connected to the discharge port at the bottom of the hopper (10), and the discharge port of the horizontal conveyor (11) is provided with an inclined conveyor (12) that is inclined upward.

7. The vacuum drum filter for waste diatomaceous earth according to claim 1, characterized in that: The treatment tank is equipped with a slag loosening assembly located between the drum (1) and the slag scraping assembly (9) and acting on the lower end of the conveying surface of the filter cloth (2). The assembly includes a vibrating plate (13) attached to the lower end of the conveying surface of the filter cloth (2). The upper side wall of the lower side of the vibrating plate (13) is provided with a slot (131). An air passage is provided inside the slot (131). A plurality of air jet holes (132) connected to the air passage are provided on the upper end wall of the slot (131).

8. A method of using a waste diatomaceous earth vacuum drum filter, characterized in that: The waste diatomaceous earth vacuum drum filter as described in any one of claims 1-7 includes the following steps: Step 1, Pre-coating stage: The pre-coating slurry is evenly coated onto the conveyed filter cloth (2) using the coating box (8). With vacuum assistance from the negative pressure roller (5), the diatomaceous earth particles are trapped on the surface of the filter cloth. After multiple cycles of pre-coating, the layers are stacked until the pre-coating thickness reaches 2-3 mm. Step 2, Filtration stage: Raise the slurry tank (3) upward to ensure that the filter cloth (2) area at the bottom of the drum (1) can be immersed in the waste diatomaceous earth slurry to be filtered. The part submerged in the slurry tank (3) continues to form a filter cake, while the part that leaves the liquid surface is dehydrated. When the drum (1) rotates to the slag scraping assembly (9), the filter cake is scraped off using a silicone scraper (91), and the scraped filter cake is discharged laterally outward from the inclined slag discharge trough (92). Step 3, rinsing stage: After filtering for a period of time, the pre-coating layer is gradually exhausted. The filter cake is ultrasonically vibrated and pneumatically loosened using a vibrating plate (13). The distance between the silicone scraper (91) and the filter cloth (2) is adjusted and scraped off uniformly. Then, the filter cloth (2) is rinsed in reverse using a rinsing pipe (14). Step 4: Repeat the pre-coating process from Step 1, and repeat the process.

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