A post-reaction filtration device for urea anticaking agents

Abstract

The application discloses a kind of for urea anti-blocking agent post-reaction filtering device, it is related to chemical filtering equipment field, including filter cylinder and heat transfer cylinder, there are two independent filter chambers in heat transfer cylinder;Filter cylinder outer wall is equipped with electric heating assembly, coarse filter screen and fine filter screen are equipped in filter chamber from top to bottom, filter screen side is equipped with absorption sleeve with negative pressure suction, can be sucked in real time and remove trapped crystal;The regenerative effect of back flushing liquid flow is realized by water-proof air-permeable membrane to push clean liquid to back flush filter screen, back flushing liquid flow can drive stirring fan blade and rotating rod to rotate, drive planetary swing body and scraping strip to reciprocatingly scrape filter screen surface, cooperate back flushing and negative pressure to form triple cleaning, the application is realized continuous production using double-cavity alternate operation, constant temperature, negative pressure, back flushing, scraping synergy, can effectively solve filter screen easy to block, crystal difficult to clean, cannot continuous operation, foam pollution and liquid leakage and other problems, suitable for urea anti-blocking agent post-reaction solid-liquid separation and continuous filtering operation.

Description

Technical Field

[0001] This invention relates to the field of chemical filtration equipment technology, specifically to a filtration device used after the reaction of urea anti-caking agent. Background Technology

[0002] Liquid urea anti-caking agents are widely used in the fertilizer industry to spray onto the surface of urea granules to improve their flowability and storage stability. These anti-caking agents typically contain a variety of functional components, such as nonionic surfactants (e.g., fatty alcohol polyoxyethylene ether, AEO-9) as wetting and dispersing agents, and polyvinyl alcohol (PVA) as a film-forming and viscosity modifier.

[0003] During the production process, after the above components are fully mixed and reacted in the reactor by heating (e.g., heating to 80-90°C), in order to ensure the purity of the product and remove unreacted solid particles, mechanical impurities or gel-like byproducts, the finished product usually needs to be filtered. The conventional filtration process is to pump the material to a bag filter or cartridge filter after the material has completed the reaction and cooled to room temperature (e.g., below 40°C) to intercept impurities.

[0004] However, in actual production, it was found that for specific liquid anti-caking agent systems containing AEO-9 and PVA, the conventional "cooling and filtration" process suffers from severe filter clogging problems. While nonionic surfactants such as AEO-9 in the formulation completely dissolve at high temperatures (e.g., 80-90℃), they precipitate from the liquid when the temperature drops below their cloud point (e.g., to around 40℃), forming a large number of micron-sized soft crystalline particles. Although PVA does not precipitate solids at 40℃, its polymer chains undergo hydrogen bonding at low temperatures. The association caused by the enhancement leads to a significant increase in the overall viscosity of the system. At the same time, PVA molecules are easily adsorbed and deposited on the surface of the filter wire, forming a dense and viscoelastic gel film. When the liquid anti-caking agent enters the filter, the dense and viscoelastic gel film on the filter surface easily sticks to the precipitated crystal particles, which can easily clog the filter. During filtration, it is necessary to replace and clean it, which is not conducive to the continuous filtration of the liquid urea anti-caking agent after the reaction. Therefore, we propose a filtration device for the urea anti-caking agent after the reaction. Summary of the Invention

[0005] The purpose of this invention is to provide a filtration device for urea anti-caking agent reaction to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a filtration device for urea anti-caking agent reaction, comprising a filter cylinder, a heat transfer cylinder inside the filter cylinder, and an axially extending partition inside the heat transfer cylinder, the partition dividing the interior of the heat transfer cylinder into two independent filtration chambers; a sealing cap is provided at the top of the filter cylinder, and a three-way pipe is provided on the sealing cap, the bottom two ends of the three-way pipe being connected to the two filtration chambers respectively, and the top end of the three-way pipe being used to connect to the discharge port of the reaction vessel; control valves are provided at the connection points between the three-way pipe and each filtration chamber; an installation groove is provided on the outer wall of the filter cylinder, and an electric... The heating component, an electric heating component, transfers heat to the interior of the filter chamber through a heat transfer cylinder. The filter chamber contains a coarse filter and a fine filter, arranged sequentially from top to bottom. An absorption sleeve is located at the connection between the coarse and fine filters and the partition. A discharge pipe is connected to the absorption sleeve, passing through the heat transfer cylinder and the filter cylinder and extending to the outside. A negative pressure component is located outside the filter cylinder, communicating with the top of the absorption sleeve to generate negative pressure within the absorption sleeve to remove crystalline particles. A backflushing component is located at the bottom of the filter cylinder; when the control valve is closed, the backflushing component reverses the flow of the filtered liquid urea anti-caking agent, impacting the filter screen.

[0007] Preferably, the bottom of the filter cylinder is conical, and a discharge bend is connected to the conical cylinder. Switch valves are distributed on the discharge bend. A limiting step is provided on the inner wall of the filter cylinder, and the bottom of the heat transfer cylinder is inserted into the limiting step.

[0008] Preferably, each filter chamber is provided with two locking grooves; both sides of the partition are made of magnetic material; the filter screen is provided with a frame, which includes an adsorption metal plate and an arc-shaped plate. The adsorption metal plate is adsorbed to the magnetic surface of the partition, and the arc-shaped plate is adapted to the inner wall of the heat transfer cylinder. The arc-shaped plate is provided with an elastic compression section, which is inserted into the locking groove; both the coarse filter screen and the fine filter screen are woven from stainless steel wire, and the ratio of the aperture of the coarse filter screen to the aperture of the fine filter screen is not less than 3:1.

[0009] Preferably, the arc-shaped plate is provided with an arc-shaped avoidance section for avoiding the absorption sleeve, the length of the absorption sleeve connected to the fine filter screen is greater than the length of the absorption sleeve connected to the coarse filter screen, the absorption sleeve is provided with an absorption port, and the absorption port is provided with a drainage slope surface.

[0010] Preferably, the negative pressure component includes an exhaust pipe connected to the top of the absorption sleeve. The exhaust pipe passes through the heat transfer cylinder and the filter cylinder in sequence, and the exhaust pipes located in the same filter chamber are connected by a connecting pipe. A negative pressure pipe is connected to the middle of the connecting pipe, and a vacuum pump is connected to one end of the negative pressure pipe.

[0011] Preferably, the electric heating assembly includes electric heating plates circumferentially distributed in the mounting groove. Multiple electric heating plates are distributed circumferentially in the mounting groove and connected in series. An insulation cover is fitted over the outside of the mounting groove. The insulation cover is fixed to the outer wall of the filter cylinder by screws. An explosion-proof electrical control box is installed outside the insulation cover. The explosion-proof electrical control box is electrically connected to the electric heating plates. The heating temperature of the electric heating plates is configured to be 50-55℃.

[0012] Preferably, the partition has a rotating groove in the middle, and a rotating rod is installed in the rotating groove. A stirring fan blade is installed at the bottom of the rotating rod. The partition has two swing grooves communicating with the rotating groove. One swing groove is located on the upper part of the coarse filter screen, and the other swing groove is located on the upper part of the fine filter screen. A planetary swing body is provided in the swing groove. The planetary swing body is fitted on the rotating rod. The planetary swing body has a contour track groove. A moving rod is fitted in the contour track groove, and a scraper is installed at the top of the moving rod.

[0013] Preferably, the backflushing assembly includes an air pump disposed at the bottom of the filter cylinder, a sealing body is installed at the bottom of the filter cylinder, a waterproof and breathable membrane is installed at the bottom of the sealing body, and an air pump is installed with an air blower connected to the waterproof and breathable membrane.

[0014] Preferably, a sealing column is installed on the sealing body, the sealing column is interference-fitted with the filter cylinder, the sealing column is a cavity, and defoamer is distributed in the cavity.

[0015] Preferably, the top of the sealed column is provided with a filter plate.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs dual independent filtration chambers in conjunction with a three-way pipe and control valves, enabling alternating operation of one chamber for filtration and the other for backwashing and regeneration. Online cleaning of the filter screen can be completed without stopping the machine, significantly improving the continuity and efficiency of urea anti-caking agent filtration production. At the same time, the chambers are independently separated and do not interfere with each other, effectively avoiding mutual influence between filtration and backwashing operations and improving the stability of the device operation.

[0017] 2. This invention uses an electric heating component to stably control the filter chamber at 50-55℃, keeping the AEO-9 crystals in a soft and loose state, which greatly reduces the adhesion strength of the crystals on the filter surface. Combined with the negative pressure absorption sleeve, the crystals are removed and intercepted in real time, reducing filter clogging from the source, extending the service life of the filter, and reducing maintenance frequency and production costs.

[0018] 3. This invention uses backflow air to drive the clean liquid to backwash the filter screen, while hydraulic force drives the stirring fan blades, rotating rod and planetary oscillator to move, so as to realize the automatic reciprocating scraping of the filter screen surface by the scraper, forming a triple cleaning structure of backflow, scraping and negative pressure suction, so that the filter screen regeneration is more thorough; combined with the defoaming and waterproof and breathable structure, foam pollution and liquid leakage are avoided, improving filtration quality and operational safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention after the sealing cover is opened; Figure 3 This is a schematic diagram of the structure of the heat transfer cylinder and filter screen of the present invention; Figure 4 for Figure 3 A front view structural diagram; Figure 5 Schematic diagram of coarse and fine filter screens; Figure 6 A schematic diagram of the structure of the heat transfer cylinder and the negative pressure component; Figure 7 This is a schematic diagram of the rotating rod and scraper structure; Figure 8 This is a schematic diagram of the insulation cover and filter cylinder structure. Figure 9 This is a schematic diagram of a partial cross-section of the sealed column. Figure 10 This is a schematic diagram of the structure of the filter cylinder; Figure 11 for Figure 7 A magnified structural diagram of region A in the middle.

[0020] In the diagram: 1. Filter cylinder; 2. Heat transfer cylinder; 3. Electric heating assembly; 4. Absorption sleeve; 5. Negative pressure component; 6. Backflushing assembly; 7. Rotating rod; 11. Sealing cover; 12. T-connector; 13. Control valve; 14. Mounting groove; 15. Discharge bend; 16. Switch valve; 17. Limiting step; 21. Baffle; 22. Coarse filter screen; 23. Fine filter screen; 24. Engaging groove; 25. Adsorption metal plate; 26. Arc-shaped plate; 27. Elastic compression section; 28. Arc-shaped clearance section; 29. 31. Rotating trough; 32. Electric heating plate; 33. Insulation cover; 34. Explosion-proof electrical control box; 45. Discharge pipe; 46. Absorption port; 47. Drainage slope; 58. Air extraction pipe; 59. Connecting pipe; 50. Negative pressure pipe; 51. Vacuum pump; 62. Air pump; 63. Sealing body; 64. Waterproof and breathable membrane; 65. Air blowing pipe; 66. Sealing column; 77. Filter plate; 78. Stirring fan blade; 79. Swinging trough; 70. Planetary oscillator; 71. Contour trajectory trough; 72. Moving rod; 73. Scraper. Detailed Implementation

[0021] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a technical solution: a filtration device for urea anti-caking agent after reaction. The device is a vertical cylindrical structure, mainly composed of a filter cylinder 1, a heat transfer cylinder 2, an electric heating component 3, a scraping absorption structure, a negative pressure component 5, a backflushing component 6, and a dual-chamber filtration mechanism. The components work together to complete the heating, graded filtration, crystal removal, filter screen regeneration, and continuous discharge of the urea anti-caking agent. The electric heating, negative pressure suction, and gas backflushing all adopt mature existing industrial technologies and work together with the proprietary structure of this invention.

[0023] The filter cylinder 1 is the main outer shell of the device. The bottom adopts a conical cylinder structure to facilitate the collection and complete discharge of the clear liquid. The inner wall of the filter cylinder 1 is provided with a limiting step 17. The bottom of the heat transfer cylinder 2 is directly inserted into the limiting step 17 to achieve coaxial positioning and stable support, ensuring that no deviation occurs during operation.

[0024] The heat transfer cylinder 2 is evenly divided into two completely independent filter chambers by axially arranged baffles 21. The two chambers can be fed, filtered and backwashed separately without interfering with each other, realizing alternating continuous operation. The two sides of the baffles 21 are made of magnetic material to cooperate with the filter screen frame to achieve rapid adsorption and fixation.

[0025] Each filter chamber is equipped with two filter screens from top to bottom: a coarse filter screen 22 and a fine filter screen 23. Both are made of woven stainless steel wire. The pore size of the coarse filter screen 22 is no less than three times that of the fine filter screen 23, which can realize the graded treatment of pre-filtration of large particulate impurities and fine filtration of soft crystals.

[0026] The filter screen is completely wrapped in a frame. The side of the frame facing the partition 21 is an adsorption metal plate 25, which can be tightly attracted to the magnetic surface of the partition 21. The other side of the frame is an arc-shaped plate 26, which is adapted to the curvature of the inner wall of the heat transfer cylinder 2. The end of the arc-shaped plate 26 is provided with an elastic compression section 27, which can be elastically inserted into the locking groove 24 on the inner wall of the filter chamber, forming a double fixation of magnetic adsorption and elastic locking, ensuring that the filter screen does not loosen or deform under the impact of liquid flow. The arc-shaped clearance section 28 is opened at the position of the absorption sleeve 4 on the arc-shaped plate 26 to avoid assembly interference.

[0027] Both the coarse filter 22 and the fine filter 23 are equipped with absorption sleeves 4 on the side near the partition 21. The absorption sleeves 4 have absorption ports 42, and the inner side of the absorption ports 42 is provided with a flow-guiding slope 43 to facilitate the smooth entry of crystals. The absorption sleeves 4 that are matched with the fine filter 23 are longer and have a larger coverage area, which can more fully absorb and remove the trapped soft crystals. The top of the absorption sleeve 4 is connected to the exhaust pipe 51, and the bottom is connected to the discharge pipe 41. The discharge pipe 41 extends out of the cylinder to discharge the collected crystals.

[0028] An annular mounting groove 14 is opened on the outer wall of the filter cylinder 1. Multiple electric heating plates 31 are evenly arranged in the mounting groove 14 along the circumference and connected in series. An external heat insulation cover 32 is fastened to reduce heat loss. An explosion-proof electrical control box 33 is installed on the outside of the heat insulation cover 32 to control the heating temperature to be stable at 50-55℃. The heat is evenly conducted to the filter chamber through the heat transfer cylinder 2, so that the AEO-9 crystals remain in a soft state and the adhesion strength is reduced.

[0029] The suction pipe 51 at the top of the absorption sleeve 4 extends upward through the heat transfer cylinder 2 and the filter cylinder 1. The suction pipes 51 in the same chamber converge into the connecting pipe 52, and then are connected to the vacuum pump 54 through the negative pressure pipe 53 to form a complete negative pressure gas path. During operation, a stable negative pressure is formed inside the absorption sleeve 4 to achieve real-time removal of crystals.

[0030] A backflushing assembly 6 is installed at the bottom of the filter cylinder 1. A high-pressure gas is supplied by an air pump 61 and delivered to the sealing body 62 through an air blower 64. A waterproof and breathable membrane 63 is installed at the bottom of the sealing body 62. This membrane is made of polytetrafluoroethylene with a pore size of 0.1-0.45 micrometers and a pressure resistance of not less than 0.3 MPa. It allows gas to pass through and prevents liquid leakage. A sealing column 65 is installed above the sealing body 62 and is filled with defoamer. A filter plate 66 is installed on the top to prevent the defoamer from entering the chamber and contaminating the material.

[0031] A rotating groove 29 is opened in the center of the partition 21. The rotating rod 7 is installed inside the rotating groove 29 and connected to the bottom of the stirring fan blade 71, which can stir the liquid at the bottom to prevent sedimentation. A planetary oscillator 73 is sleeved on the rotating rod 7. The planetary oscillator 73 is located in the oscillation groove 72 and has a contoured trajectory groove 74 on its surface. The moving rod 75 is inserted into the contoured trajectory groove 74. The top scraper 76 is in contact with the surface of the filter screen. When the rotating rod 7 rotates, it drives the scraper 76 to scrape back and forth along the predetermined trajectory to help clean the crystals on the surface of the filter screen.

[0032] The electric heating component 3 adopts the mature industrial electric heating plate constant temperature control technology, which is a conventional temperature control method. The electric heating plate 31 uses stainless steel armored heating elements, which have good insulation, high thermal efficiency and long service life. Multiple electric heating plates 31 are evenly arranged along the outer circumference of the filter cylinder 1 to ensure uniform circumferential heating.

[0033] The electric heating plate 31 is powered and controlled by the explosion-proof electrical control box 33. The explosion-proof electrical control box 33 has a built-in temperature sensor, PID adjustment module and relay, all of which are existing mature control components. The temperature sensor collects the internal temperature of the filter chamber in real time and feeds it back to the explosion-proof electrical control box 33. The PID adjustment module automatically adjusts the output power according to the set value of 50-55℃. When the temperature is lower than the set lower limit, the circuit is turned on to heat up. When the upper limit is reached, the circuit is turned off to stop heating, so as to realize constant temperature automatic control.

[0034] Heat is transferred from the electric heating plate 31 to the filter cylinder 1, and then evenly conducted to the interior of the two independent filter chambers through the heat transfer cylinder 2, so that the temperature in the entire chamber remains stable. The heat insulation cover 32 is made of rock wool or polyurethane insulation material and is wrapped around the outside of the mounting groove 14, which greatly reduces the heat loss to the outside and improves the heating efficiency.

[0035] The core function of heating: AEO-9 crystals remain soft, loose, and have low adhesion at 50-55℃, preventing them from hardening and caking on the filter screen surface. This facilitates both negative pressure suction and backwashing, fundamentally solving the industry problem of low-temperature crystallization hardening and filter screen clogging.

[0036] Before starting the device, the electric heating plate 31 is activated via the explosion-proof electrical control box 33 to preheat the filter chamber to 50-55℃ and maintain a constant temperature. This temperature range is between the cloud point temperature of AEO-9 crystallization and room temperature, ensuring a stable operating environment within the filter chamber while keeping the precipitated AEO-9 crystals soft and loose. This significantly reduces the adhesion strength and accumulation hardness of the crystals on the filter screen surface, making them easier to be removed by negative pressure and backwash, thus preventing hardened crystals from clogging the filter screen pores. The heat insulation cover 32 continuously reduces heat loss, ensuring a uniform and stable temperature inside the chamber.

[0037] After preheating, open the control valve 13 on one side of the three-way pipe 12, while keeping the other side closed. The liquid urea anti-caking agent output from the reactor outlet enters the opened filter chamber through the three-way pipe 12, while the other chamber remains in standby mode.

[0038] After the filtrate enters the chamber, it flows from top to bottom, first contacting the coarse filter screen 22. The coarse filter screen 22 intercepts large mechanical impurities, undissolved PVA clumps, and other hard foreign objects, preventing them from directly impacting the fine filter screen 23 and causing blockage or damage. The liquid that has passed through the coarse filter continues to flow downward through the fine filter screen 23. The fine filter screen 23 traps the AEO-9 micron-sized soft crystals that precipitate in the liquid, completing the fine filtration. The filtered clear liquid passes through the filter screen and flows downward to the conical area at the bottom of the filter cylinder 1.

[0039] The negative pressure component 5 adopts the mature industrial water ring / rotary vane negative pressure suction technology. The vacuum pump 54 is an existing standard industrial negative pressure generating device. Its working principle is as follows: the motor drives the rotor inside the pump body to rotate at high speed. Through the change of volume, a local vacuum negative pressure zone is formed inside the pump chamber. The negative pressure is transmitted to the inside of each absorption sleeve 4 through the negative pressure pipe 53, the connecting pipe 52, and the air extraction pipe 51, so that a continuous and stable negative pressure field is formed inside the absorption sleeve 4.

[0040] The negative pressure can be adjusted by the regulating valve on the vacuum pump 54 to ensure that the adsorption force is moderate, which can remove soft crystals without causing the electrode to deform or the filter to break due to excessive suction.

[0041] During the filtration process, the vacuum pump 54 runs continuously, forming a stable negative pressure inside the absorption sleeve 4 through the negative pressure pipe 53, the connecting pipe 52, and the suction pipe 51. The soft crystals trapped on the surface of the fine filter screen 23 are adsorbed to the absorption port 42 under the action of negative pressure. The flow slope 43 guides the crystals smoothly into the interior of the absorption sleeve 4, avoiding accumulation at the edges. Under the action of negative pressure, the crystals and part of the filtered residual liquid flow along the flow slope 43. The residual liquid will flow back into the filter cylinder 1. At the same time, because the absorption sleeve 4 is vertical, the residual liquid will also flow back under its own gravity.

[0042] After the crystals enter the absorption sleeve 4, they are discharged outward along the discharge pipe 41 to an external collection container, realizing real-time separation of crystals and clear liquid, greatly reducing the accumulation of crystals on the filter screen surface and slowing down the clogging speed.

[0043] After a period of filtration in a single chamber, residual crystals on the filter screen surface cause the filtration resistance to increase. At this time, the control valve 13 corresponding to that chamber is closed to stop the feeding, while the control valve 13 of another chamber is opened. The filtrate is then switched to the new chamber to continue filtration, thus achieving continuous production without stopping the machine.

[0044] The backflushing assembly 6 is activated for the chamber where the feed has been closed. The air pump 61 adopts mature industrial vortex or piston air pump technology, which is a common pneumatic device. The air pump 61 is driven by a motor to rotate the internal impeller, generating continuous and stable compressed air with a pressure range of 0.1-0.3MPa, which meets the backflushing requirements and will not damage the filter screen.

[0045] Compressed gas is delivered through the vent pipe 64 to the waterproof and breathable membrane 63 at the bottom of the sealing body 62. The waterproof and breathable membrane 63 is an existing mature polymer separation membrane made of polytetrafluoroethylene with a pore size of 0.1-0.45μm. It has the characteristics of being breathable but not liquid-permeable, allowing gas to pass through freely, while the liquid urea anti-caking agent cannot leak due to surface tension, ensuring the safety and stability of the backflush gas path.

[0046] Gas passes through the membrane and enters the bottom of the chamber, quickly pushing the filtered liquid to form an upward reverse water flow. The reverse water flow flows from bottom to top through the filter screen with a certain pressure, strongly washing the surfaces of the coarse filter screen 22 and the fine filter screen 23, completely washing away the attached crystals from the filter screen surface, and completing physical regeneration.

[0047] The backwash-driven stirring-rotation-scraping complete transmission process: The upward high-speed flow of clear liquid directly impacts the blades of the stirring fan 71, which is hydraulically driven to rotate around the axis of the rotating rod 7. The rotation of the stirring fan 71 can continuously disturb the clear liquid at the bottom, disrupting the crystallization and condensation conditions, preventing the filtered clear liquid from cooling, stratifying, and condensing in the low-temperature zone at the bottom, and maintaining a uniform liquid flow.

[0048] The stirring fan blade 71 synchronously drives the rotating rod 7 to rotate, and the rotating rod 7 further drives the planetary oscillator 73 to rotate synchronously. The planetary oscillator 73 has a continuous undulating contour groove 74 on its surface. The bottom of the moving rod 75 is engaged in the contour groove 74. As the planetary oscillator 73 rotates, the bottom of the moving rod 75 swings up and down periodically along the crests and troughs of the contour groove, thereby driving the scraper 76 at the top of the moving rod 75 to perform a continuous reciprocating scraping action on the surfaces of the coarse filter screen 22 and the fine filter screen 23.

[0049] The scraper 76 is made of flexible and wear-resistant material, which gently scrapes away the crystals attached to the filter screen surface. Combined with reverse water flow flushing and negative pressure absorption sleeve suction, it forms a triple cleaning structure of backwash flushing + mechanical scraping + negative pressure suction, which thoroughly removes residual crystals on the filter screen surface. The regeneration effect is far superior to a single backwash structure.

[0050] During backflushing, the foam generated rises through the sealed column 65 and is quickly broken up by the internal defoamer. The filter plate 66 blocks the defoamer particles, preventing them from entering the filtration chamber and contaminating the product. After backflushing is completed, the control valve 13 of the chamber is reopened to resume filtration. The two chambers alternate in circulation, achieving long-term stable operation.

[0051] During normal filtration operation, the downward flow of liquid within the chamber also drives the stirring fan blades 71 to rotate at low speed, stirring the liquid at the bottom of the chamber and preventing crystals from accumulating and hardening. Simultaneously, the rotating rod 7 drives the planetary oscillator 73 to move, and the contour groove 74 drives the moving rod 75 and the scraper 76 to reciprocate along the filter screen surface, gently scraping away the attached crystals, further improving the cleaning effect and reducing the backwash frequency.

[0052] The filtered liquid collects at the bottom of the conical cylinder. Opening the valve 16 on the discharge bend 15 allows the liquid to be steadily discharged through the discharge bend 15 into the finished product collection container. The conical structure ensures complete discharge of the liquid, reducing internal residue.

[0053] When maintenance is required after long-term use, simply open the sealing cover 11, pull the filter screen frame upwards, the magnetic surface of the adsorption metal plate 25 and the partition 21 will separate, and the elastic compression section 27 will come out from the locking groove 24, so that the filter screen can be quickly removed for cleaning or replacement. During assembly, the reverse operation can be used to quickly position and fix it, making maintenance convenient and efficient.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A filtration device for urea anti-caking agent reaction, comprising a filter cylinder (1), characterized in that: The filter cylinder (1) is provided with a heat transfer cylinder (2), and the heat transfer cylinder (2) is provided with a partition (21) extending along the axial direction. The partition (21) divides the interior of the heat transfer cylinder (2) into two independent filter chambers. The top of the filter cylinder (1) is provided with a sealing cover (11), and a three-way pipe (12) is provided on the sealing cover (11). The bottom two ends of the three-way pipe (12) are respectively connected to two filter chambers. The top end of the three-way pipe (12) is used to connect to the outlet of the reactor. Control valves (13) are provided at the connection between the three-way pipe (12) and each filter chamber. The outer wall of the filter cylinder (1) is provided with an installation groove (14), and an electric heating component (3) is provided in the installation groove (14). The heat generated by the electric heating component (3) is transferred to the interior of the filter chamber through the heat transfer cylinder (2). The filter chamber is provided with a coarse filter screen (22) and a fine filter screen (23) from top to bottom. An absorption sleeve (4) is provided at the connection between the coarse filter screen (22) and the fine filter screen (23) and the partition (21). A discharge pipe (41) is connected to the absorption sleeve (4). The discharge pipe (41) passes through the heat transfer cylinder (2) and the filter cylinder (1) in sequence and extends to the outside. The filter cylinder (1) is provided with a negative pressure component (5) on the outside. The negative pressure component (5) is connected to the top of the absorption sleeve (4) and is used to generate negative pressure in the absorption sleeve (4) to remove crystal particles. The filter cylinder (1) is provided with a backflushing component (6) at the bottom. When the control valve (13) is closed, the backflushing component (6) will backflush the filtered liquid urea anti-caking agent against the filter screen.

2. A filtration device for urea anti-caking agent reaction as described in claim 1, characterized in that: The bottom of the filter cylinder (1) is a conical cylinder, and the upper part of the conical cylinder is connected to a discharge bend (15). A switch valve (16) is distributed on the discharge bend (15). The inner wall of the filter cylinder (1) is provided with a limiting step (17), and the bottom of the heat transfer cylinder (2) is inserted into the limiting step (17).

3. A filtration device for urea anti-caking agent reaction as described in claim 1, characterized in that: Each filter chamber is provided with two locking grooves (24); both sides of the partition (21) are made of magnetic material; the filter screen is provided with a frame, which includes an adsorption metal plate (25) and an arc plate (26). The adsorption metal plate (25) is adsorbed to the magnetic surface of the partition (21), and the arc plate (26) is adapted to the inner wall of the heat transfer cylinder (2). The arc plate (26) is provided with an elastic compression section (27), which is inserted into the locking groove (24); both the coarse filter screen (22) and the fine filter screen (23) are made of stainless steel wire, and the ratio of the aperture of the coarse filter screen (22) to the aperture of the fine filter screen (23) is not less than 3:

1.

4. A filtration device for urea anti-caking agent reaction as described in claim 3, characterized in that: The arc plate (26) is provided with an arc-shaped avoidance section (28) for avoiding the absorption sleeve (4). The length of the absorption sleeve (4) connected to the fine filter screen (23) is greater than the length of the absorption sleeve (4) connected to the coarse filter screen (22). The absorption sleeve (4) is provided with an absorption port (42) and a drainage slope (43) is provided at the absorption port (42).

5. A filtration device for urea anti-caking agent reaction as described in claim 4, characterized in that: The negative pressure component (5) includes an air extraction pipe (51) connected to the top of the absorption sleeve (4). The air extraction pipe (51) passes through the heat transfer cylinder (2) and the filter cylinder (1) in sequence. The air extraction pipes (51) located in the same filter chamber are connected by a connecting pipe (52). A negative pressure pipe (53) is connected to the middle of the connecting pipe (52), and a vacuum pump (54) is connected to one end of the negative pressure pipe (53).

6. A filtration device for urea anti-caking agent reaction as described in claim 1, characterized in that: The electric heating assembly (3) includes electric heating plates (31) circumferentially distributed in the mounting groove (14). Multiple electric heating plates (31) are distributed circumferentially in the mounting groove (14) and connected in series. The mounting groove (14) is covered with a heat insulation cover (32). The heat insulation cover (32) is fixed to the outer wall of the filter cylinder (1) by screws. An explosion-proof electrical control box (33) is installed on the outside of the heat insulation cover (32). The explosion-proof electrical control box (33) is electrically connected to the electric heating plates (31). The heating temperature of the electric heating plates (31) is configured to be 50-55℃.

7. A filtration device for urea anti-caking agent reaction as described in claim 1, characterized in that: The partition (21) has a rotating groove (29) in the middle, and a rotating rod (7) is installed at the rotating groove (29). A stirring fan blade (71) is installed at the bottom of the rotating rod (7). The partition (21) has two swing grooves (72) that communicate with the rotating groove (29). One swing groove (72) is located on the upper part of the coarse filter screen (22), and the other swing groove (72) is located on the upper part of the fine filter screen (23). A planetary swing body (73) is provided at the swing groove (72). The planetary swing body (73) is sleeved on the rotating rod (7). The planetary swing body (73) has a contour track groove (74). A moving rod (75) is sleeved at the contour track groove (74), and a scraper (76) is installed at the top of the moving rod (75).

8. A filtration device for urea anti-caking agent reaction as described in claim 1, characterized in that: The backwash assembly (6) includes an air pump (61) disposed at the bottom of the filter cylinder (1), a sealing body (62) is installed at the bottom of the filter cylinder (1), a waterproof and breathable membrane (63) is installed at the bottom of the sealing body (62), and an air pump (61) is equipped with an air blower (64) connected to the waterproof and breathable membrane (63).

9. A filtration device for urea anti-caking agent reaction as described in claim 8, characterized in that: A sealing column (65) is installed on the sealing body (62). The sealing column (65) is press-fitted with the filter cylinder (1). The sealing column (65) is a cavity, and defoamer is distributed in the cavity.

10. A filtration device for urea anti-caking agent reaction as described in claim 9, characterized in that: The top of the sealed column (65) is provided with a filter plate (66).

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