A multi-stage filtration device and process for crystallization of chemical raw materials

Abstract

The invention relates to the technical field of filtering devices, and specifically discloses a multi-stage filtering device and process for crystallization of chemical raw materials, comprising a box shell, a filter box, a separation box, a roller, a filter cloth and an air pump, wherein the upper end of the filter box is connected to a liquid inlet pipe; the lower end of the separation box is connected to a material discharge trough, and a nozzle and a material guide membrane are arranged in the separation box; a plurality of rollers are rotatably installed in the box shell; the filter cloth is wound around the plurality of rollers in a closed ring shape so as to circulate counterclockwise under the drive of the rollers, the filter cloth is stacked with multiple layers, the aperture of the filter cloth gradually decreases from the outer layer to the inner layer, the upper part of the multi-layer filter cloth passes through the filter box, the left part of the multi-layer filter cloth passes through the separation box, the nozzle faces the reverse side of each layer of filter cloth, and the material guide membrane is arranged on the front side of each layer of filter cloth; the air pump is provided with an air extraction pipe connected to the lower part of the filter box and an air supply pipe connected to the nozzle. The multi-stage filtering device and process for crystallization of chemical raw materials improves the filtering efficiency and provides a higher quality filtering effect.

Description

Technical Field

[0001] The invention relates to the technical field of filtering devices, and in particular to a multi-stage filtering device and process for crystallizing chemical raw materials. Background Art

[0002] Boric acid is an important inorganic compound, which is widely used in glass, ceramics, metallurgy, medicine, pesticides and other fields. The manufacturing methods of boric acid mainly include sulfuric acid method, hydrochloric acid method and carbonic acid method. Among them, the hydrochloric acid method is to react boric magnesium ore powder with hydrochloric acid to generate boric acid and magnesium chloride. The solution after the reaction is filtered to remove solid impurities, so that the boric acid solution can be purified, and the boric acid is precipitated from the solution by crystallization. After crystallization, a mother liquor containing boric acid crystals will be produced, and these crystals need to be separated from the mother liquor. Filtration is a common method to separate boric acid crystals from mother liquor. By removing uncrystallized impurities and mother liquor through a filtration device, a pure boric acid product can be obtained.

[0003] A Chinese patent document with authorization announcement number CN217724822U discloses a separation device for processing ammonium sulfate crystals. The separation device for processing ammonium sulfate crystals is provided with a separation mechanism, an air-drying mechanism and a replacement mechanism on the separation device body. The setting of the separation mechanism enables the filter cloth to drive the ammonium sulfate slurry for centrifugal separation, and the separated ammonium sulfate remains in the filter cloth. The setting of the air-drying mechanism enables hot air to dry the ammonium sulfate in the filter cloth to obtain ammonium sulfate crystals. The setting of the replacement mechanism facilitates the removal of the filter cloth to obtain the ammonium sulfate crystals in the filter cloth, and the filter cloth is replaced for the next separation operation.

[0004] However, during use of the above-mentioned separation device for ammonium sulfate crystal processing in the prior art, the filtration area of ​​the filter cloth is limited and may not be able to effectively capture all solid crystals, resulting in low filtration efficiency. In addition, the filter cloth is easily blocked quickly due to excessive solid crystals, resulting in the inability to effectively separate the solid crystals from uncrystallized impurities and mother liquor, resulting in poor filtration quality. Summary of the invention

[0005] The invention provides a multi-stage filtering device and process for crystallization of chemical raw materials, aiming to solve the problems of low filtering efficiency and poor filtering quality existing in a separation device for processing ammonium sulfate crystals in the related art.

[0006] The present invention provides a multi-stage filtration device for crystallization of chemical raw materials, which adopts the following technical scheme:

[0007] A multi-stage filtering device for crystallization of chemical raw materials, comprising a box shell provided with a liquid inlet pipe and a material outlet trough, and further comprising: a filter box, the filter box is arranged in the box shell, the upper end of the filter box is connected to the liquid inlet pipe; a separation box, the separation box is arranged in the box shell and is located on the left side of the filter box, the lower end of the separation box is connected to the material outlet trough, a nozzle and a material guide membrane are arranged in the separation box, and the material guide membrane has a material guide slope toward the material outlet trough; a roller, a plurality of the rollers are rotatably installed in the box shell; a filter cloth, the filter cloth is wound around a plurality of rollers in a closed ring shape to pass through the rollers The filter cloth is driven to make counterclockwise circular motion, and multiple layers of the filter cloth are stacked, and the pore size of the filter cloth gradually decreases from the outer layer to the inner layer. The upper part of the multiple layers of the filter cloth passes through the filter box to filter the mother liquor, and the left part of the multiple layers of the filter cloth passes through the separation box. The nozzle faces the reverse side of each layer of the filter cloth to spray the solid crystals attached to the front side of each layer of the filter cloth, and the material guide membrane is arranged on the front side of each layer of the filter cloth to receive the blown-off solid crystals; an air pump, which is installed outside the box shell, and is provided with an exhaust pipe connected to the lower part of the filter box and an air supply pipe connected to the nozzle.

[0008] By adopting the above technical scheme, a multi-layer filter cloth is arranged in the box shell, which circulates between the filter box and the separation box; when the multi-layer filter cloth is located in the filter box, it can more effectively intercept solid crystals with smaller particle sizes to improve the filtration accuracy and reduce crystal loss, and can also increase the filtration area to improve the filtration efficiency and processing capacity, and can achieve deep filtration through filter cloth layers with different pore sizes to reduce the clogging problem of the filter cloth, thereby providing a higher quality filtration effect; when the multi-layer filter cloth enters the separation box, the solid crystals intercepted by each layer of filter cloth can be collected to achieve continuous filtration, allowing the mother liquor to flow continuously in the filter box, reducing downtime, and improving production efficiency, and the filter cloth can be cleaned online to avoid the accumulation of solid crystals on the surface of the filter cloth, keep the filtration channel unobstructed, and further improve the filtration efficiency.

[0009] Furthermore, a coarse filter box located above the filter box and connected to the filter box is also provided in the box shell, a filter screen is provided in the coarse filter box, a push plate is rotatably installed on the upper surface of the filter screen, the liquid inlet pipe extends from the side wall of the box shell to the top of the filter screen, a material guide groove is provided between the outer peripheral side of the filter screen and the inner wall of the coarse filter box, the lower end of the material guide groove is connected to the coarse material groove provided outside the box shell, and a pushing motor for driving the pushing plate to rotate is provided on the box shell.

[0010] By adopting the above technical scheme, the coarse filter box is used to perform preliminary filtration on the mother liquor containing solid crystals to separate solid crystals with larger particle sizes. In this way, the secondary filtration only needs to deal with crystals and impurities with smaller particle sizes, which reduces the burden of secondary filtration and improves the filtration efficiency. In addition, when the push plate rotates, the solid crystals with larger particle sizes on the upper surface of the filter screen can be pushed toward the inner wall of the coarse filter box, thereby realizing continuous filtration. The filter screen can also be cleaned online, thereby improving production efficiency.

[0011] Furthermore, a bulk material cap is provided in the coarse filter box and is located between the liquid inlet pipe and the push plate. The bulk material cap is in the shape of a cone with a gradually narrowing upper end, and a plurality of bulk material holes are provided on the bulk material cap. The filter screen is in the shape of a cone with a gradually narrowing lower end, the push plate is in a vortex shape, and the material guide trough has a material guide slope toward the coarse material trough.

[0012] By adopting the above technical scheme, the bulk cap is used to disperse the mother liquor entering the coarse filter box along the conical side wall of the bulk cap to the inner wall of the coarse filter box, so that the mother liquor is evenly dispersed on the filter screen, and at the same time the flow rate of the mother liquor is controlled to prevent the mother liquor from entering the coarse filter box too quickly, thereby improving the filtering efficiency of the filter screen.

[0013] Furthermore, a pressure roller and an idler roller are rotatably installed in the separation box, the part of the multi-layer filter cloth entering the separation box is located between the pressure roller and the idler roller, the two idlers support the multi-layer filter cloth upward, and the pressure roller squeezes the part of the multi-layer filter cloth located between the two idlers, and a receiving groove is provided below the two idlers, the lower end of the receiving groove is connected to the liquid guide tube, the end of the liquid guide tube facing away from the receiving groove extends into the lower end of the filter box, and the box shell is provided with an extrusion motor for driving the pressure roller to rotate and a circulation motor for driving the rotating roller to rotate.

[0014] The above technical solution is adopted to separate the moisture on the filter cloth from the intercepted solid crystals, and the squeezed moisture is introduced into the filter box and discharged together with the mother liquor after the secondary filtration, thereby assisting the drying of the solid crystals and facilitating the separation of the solid crystals from the filter cloth.

[0015] Furthermore, guide rollers arranged in pairs are rotatably installed in the separation box, and filter cloths other than the innermost filter cloth are respectively wound on the guide rollers arranged in pairs.

[0016] By adopting the above technical solution, the multiple layers of filter cloth can be changed from a superimposed state to a separated state and kept parallel to each other, so as to facilitate the separation operation of the solid crystals intercepted on the front side of each layer of filter cloth.

[0017] Furthermore, a bellows is provided in the separation box, and the end of the air supply pipe facing away from the air pump is connected to the bellows, and bronchial tubes corresponding to each layer of filter cloth are provided on the side of the bellows facing away from the air supply pipe, and a plurality of the nozzles are installed on each bronchial tube, and an air guide pipe is provided between the upper end of the separation box and the coarse filter box, and the end of the air guide pipe facing away from the separation box extends into the material guide trough.

[0018] The above technical solution is adopted to blow the solid crystals in the material guide trough to prevent the solid crystals from accumulating and staying in the material guide trough, while maintaining the stable air pressure in the cavity connecting the coarse filter box and the filter box, realizing gas circulation, reducing the entry of external air, and preventing dust and impurities carried by the external air from affecting the purity of the separated crystals.

[0019] Furthermore, a limiting frame corresponding to each layer of filter cloth is fixed in the separation box, each limiting frame extends forward and backward and is located on the reverse side of the corresponding filter cloth, and each limiting frame has a limiting groove for passing the filter cloth.

[0020] The above technical solution is adopted to limit the position of each layer of filter cloth to avoid excessive vibration of the filter cloth when the nozzle blows the filter cloth, thereby affecting the material connection effect of the material guide membrane.

[0021] Furthermore, the limiting frames except the innermost limiting frame are located between the front and back surfaces of two adjacent filter cloths and are provided with material guiding films, and the front and rear ends of the material guiding films are fixed on the limiting frames.

[0022] By adopting the above technical solution, the material guide film is made to vibrate up and down when being sprayed by the nozzle, thereby preventing solid crystals from adhering to the material guide film, which is beneficial to the transportation of solid crystals.

[0023] Furthermore, a cache box located below the filter box is also provided in the box shell, a connecting pipe is provided between the lower ends of the cache box and the filter box, and the cache box is connected to a liquid outlet pipe provided outside the box shell.

[0024] By adopting the above technical solution, the buffer box is used to buffer the mother liquor after filtration, and can keep the liquid outlet of the filter box isolated from the outside world, preventing dust and impurities carried by the outside air from entering the filter box, which is beneficial to ensuring the purity of the crystal.

[0025] The present invention also provides a multi-stage filtration process for crystallization of chemical raw materials, comprising the following steps:

[0026] The first step is to add materials, and pour the mother liquor containing solid crystals into the filter box through the liquid inlet pipe;

[0027] The second step is filtration. The roller drives the multi-layer filter cloth to circulate along a closed loop path. The multi-layer filter cloth passes through the filter box to filter the mother liquid containing solid crystals. The air pump draws air to the lower part of the filter box through the suction pipe to push the mother liquid through the multi-layer filter cloth. The solid crystals are trapped on the front of each layer of filter cloth.

[0028] The third step is separation. The multiple layers of filter cloth are moved from the filter box to the separation box. The air pump supplies air to the nozzle through the air supply pipe. The nozzle blows on the back of each layer of filter cloth, so that the solid crystals on the front of each layer of filter cloth are separated from the filter cloth and fall on the material guide membrane. The material guide membrane guides the solid crystals into the discharge trough for discharge.

[0029] By adopting the above technical scheme, the mother liquor containing solid crystals is filtered through multiple layers of filter cloth, which can more effectively intercept solid crystals with smaller particle size to improve the filtration accuracy and reduce crystal loss. It can also increase the filtration area to improve the filtration efficiency and processing capacity, and can achieve deep filtration through filter cloth layers with different pore sizes to reduce the clogging problem of the filter cloth, thereby providing a higher quality filtration effect; and the multiple layers of filter cloth are circulated between the filter box and the separation box to collect the solid crystals intercepted by each layer of filter cloth to achieve continuous filtration, reduce downtime, and improve production efficiency. The filter cloth can be cleaned online to avoid the accumulation of solid crystals on the surface of the filter cloth, keep the filtration channel unobstructed, and further improve the filtration efficiency.

[0030] The beneficial effects of a multi-stage filtering device and process for crystallization of chemical raw materials provided by the present invention are as follows: a mother liquor containing solid crystals is filtered by a multi-stage filtering method, solid crystals with larger particle sizes are first separated by preliminary filtering, and solid crystals with smaller particle sizes are separated by secondary filtering, which not only optimizes the particle size distribution and can meet the needs of different applications, but also reduces the burden of secondary filtering and improves the filtering efficiency; the secondary filtering adopts a multi-layer filter cloth, which can more effectively intercept solid crystals with smaller particle sizes to improve the filtering accuracy and reduce the crystal loss, and can also increase the filtering area to improve the filtering efficiency and processing capacity, and can realize deep filtering through filter cloth layers with different pore sizes to reduce the clogging problem of the filter cloth, thereby providing a higher quality filtering effect; and both the preliminary filtration and the secondary filtration realize continuous filtration, allowing the mother liquor to flow continuously in the filter box, reducing downtime and improving production efficiency, and the filter cloth can be cleaned online to avoid the accumulation of solid crystals on the upper surface of the filter cloth, keep the filter channel unobstructed, and further improve the filtering efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a first structural schematic diagram of the box shell of the multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0032] Figure 2It is a second structural schematic diagram of the box shell of the multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0033] Figure 3 It is a schematic diagram of the internal structure of the multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0034] Figure 4 The invention is a schematic structural diagram of a coarse filter box, a filter box and a separation box of a multi-stage filter device for crystallization of chemical raw materials.

[0035] Figure 5 It is a structural schematic diagram of a coarse filter box of a multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0036] Figure 6 It is a first structural schematic diagram of a separation box of a multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0037] Figure 7 It is a second structural schematic diagram of the separation box of the multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0038] Figure 8 It is a structural schematic diagram of an air pump and a bellows of a multi-stage filtering device for crystallization of chemical raw materials of the present invention.

[0039] Reference numerals:

[0040] 10. Box shell; 110. Liquid inlet pipe; 120. Coarse material trough; 130. Discharge trough; 140. Liquid outlet pipe; 150. Baffle; 160. Support foot; 20. Coarse filter box; 210. Bulk material cap; 220. Push plate; 221. Push motor; 230. Filter screen; 240. Grid frame; 250. Guide trough; 260. Rotating shaft; 270. Shaft frame; 30. Filter box; 320. Groove; 40. Separation box; 410. Limiting frame; 420, material guide film; 430, receiving groove; 440, liquid guide tube; 50, rotating roller; 510, circulation motor; 520, pressure roller; 521, extrusion motor; 530, support roller; 540, guide roller; 60, air pump; 610, exhaust pipe; 620, air supply pipe; 630, bellows; 640, bronchial tube; 650, nozzle; 660, air guide tube; 70, buffer box; 710, connecting pipe; 720, bracket; 80, filter cloth. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0042] like Figures 1 to 8As shown, an embodiment of the multi-stage filtration device for crystallization of chemical raw materials of the present invention includes a box shell 10, a coarse filter box 20, a push motor 221, a filter box 30, a separation box 40, a rotating roller 50, a circulation motor 510, a pressure roller 520, an extrusion motor 521, a support roller 530, a guide roller 540, an air pump 60, a buffer box 70 and a filter cloth 80.

[0043] like Figure 1 , Figure 2 , Figure 3 and Figure 5 As shown, and refer to Figure 1 In the orientation shown in , the box shell 10 is in the shape of an upright rectangular parallelepiped and includes a front panel, a rear panel, a left panel, a right panel, an upper panel and a lower panel. Among them, the outer side of the upper panel is equipped with a push motor 221, the outer side of the front panel is equipped with a liquid inlet pipe 110, a rough material tank 120, an extrusion motor 521, a discharge tank 130 and a liquid outlet pipe 140, the outer side of the rear panel is equipped with a circulation motor 510 and an air pump 60, and the bottom of the lower panel is provided with two legs 160 for supporting the box shell 10. The liquid inlet pipe 110 is used to pass the mother liquor containing solid crystals, the rough material tank 120 is used to discharge the separated solid crystals with larger particle size, the discharge tank 130 is used to discharge the separated solid crystals with smaller particle size, and the liquid outlet pipe 140 is used to discharge the filtered mother liquor. The outlet ends of the rough material tank 120 and the discharge tank 130 are respectively slidably installed with baffles 150 for opening or closing the outlet ends of the rough material tank 120 and the discharge tank 130. A coarse filter box 20 , a filter box 30 and a cache box 70 are fixed in sequence from top to bottom inside the box shell 10 , and a separation box 40 is fixed on the left side of the filter box 30 .

[0044] like Figures 3 to 5As shown, the coarse filter box 20 is cylindrical, and the interior of the coarse filter box 20 is sequentially provided with a bulk cap 210, a push plate 220, a filter screen 230, a mesh frame 240 and an axle frame 270 from top to bottom. The coarse filter box 20 is used to perform preliminary filtration on the mother liquor containing solid crystals to separate solid crystals with larger particle sizes. In this way, the secondary filtration only needs to deal with crystals and impurities with smaller particle sizes, which reduces the burden of secondary filtration and improves the filtration efficiency. The liquid inlet pipe 110 extends from the front panel of the box shell 10 to the top of the center of the bulk cap 210. The bulk cap 210 is a cone with a gradually narrowing upper end. A plurality of bulk holes are provided on the bulk cap 210 so that the mother liquor entering the coarse filter box 20 is dispersed along the conical side wall of the bulk cap 210 to the inner wall of the coarse filter box 20, so that the mother liquor is evenly dispersed on the filter screen 230, and at the same time, the flow rate of the mother liquor is controlled to prevent the mother liquor from entering the coarse filter box 20 too quickly, thereby improving the filtration efficiency of the filter screen 230. The output end of the push motor 221 is provided with a rotating shaft 260 extending into the coarse filter box 20. The rotating shaft 260 passes through the center of the bulk cap 210, the push plate 220, the filter screen 230, and the grid frame 240 in sequence and is rotatably installed on the shaft frame 270. The push plate 220 is fixed on the rotating shaft 260 to rotate with the rotating shaft 260. The push plate 220 is vortex-shaped, and the filter screen 230 is a cone with a gradually narrowing lower end, so that the mother liquor after preliminary filtration is gathered toward the center of the coarse filter box 20 along the conical side wall of the filter screen 230, and separated from the solid crystals with larger particle size on the upper surface of the filter screen 230, so as to prevent the mother liquor after preliminary filtration from being pushed out by the push plate 220. The lower end surface of the push plate 220 contacts the upper surface of the filter screen 230, so that when the push plate 220 rotates with the rotating shaft 260, the solid crystals with larger particle size on the upper surface of the filter screen 230 are pushed toward the inner wall of the coarse filter box 20, so that continuous filtration is achieved, and the solid crystals are collected while filtering, allowing the mother liquid to flow continuously in the coarse filter box 20, reducing downtime and improving production efficiency. The filter screen 230 can be cleaned online to avoid the accumulation of solid crystals on the upper surface of the filter screen 230, keep the filtration channel unobstructed, and improve the filtration efficiency. The mesh frame 240 is used to support the filter screen 230. A material guide trough 250 for collecting solid crystals is arranged between the outer peripheral side of the filter screen 230 and the inner wall of the coarse filter box 20. The lower end of the material guide trough 250 is connected to the coarse material trough 120 arranged outside the box shell 10. The material guide trough 250 has a material guide slope toward the coarse material trough 120 to guide the solid crystals with larger particle size in the material guide trough 250 to the coarse material trough 120 for discharge, thereby realizing the automatic collection of solid crystals with larger particle size, reducing manual operation and improving collection efficiency.

[0045] like Figure 3 and Figure 4As shown, the filter box 30 is in a rectangular shape, and the upper end of the filter box 30 is connected to the lower end of the coarse filter box 20, and is used to perform secondary filtration on the mother liquor after the primary filtration to separate solid crystals with smaller particle sizes. A horizontally extending avoidance opening is provided at the upper part of the filter box 30, and a groove 320 extending left and right is provided on the front and rear inner walls of the filter box 30 at the avoidance opening.

[0046] like Figure 3 , Figure 4 and Figure 6 As shown, a plurality of rollers 50 are rotatably installed in the housing 10, and the filter cloth 80 is wound around the plurality of rollers 50 in a closed ring shape, wherein one of the rollers 50 is connected to the output end of the circulation motor 510 to rotate under the drive of the circulation motor 510, thereby driving the filter cloth 80 to circulate counterclockwise, so that the filter cloth 80 circulates between the filter box 30 and the separation box 40. The filter cloth 80 is stacked in three layers, and the aperture of the filter cloth 80 gradually decreases from the outer layer to the inner layer. The upper part of the three-layer filter cloth 80 passes through the avoidance opening provided in the filter box 30, and the front and rear sides of the three-layer filter cloth 80 are slidably assembled in the groove 320 to limit the front and rear sides of the three-layer filter cloth 80. When the three-layer filter cloth 80 passes through the filter box 30, the mother liquor that has been initially filtered is subjected to secondary filtration, so that solid crystals with smaller particle sizes are trapped on the front of each layer of the filter cloth 80. By setting up multiple layers of filter cloth 80, solid crystals with smaller particle sizes can be intercepted more effectively to improve the filtering accuracy and reduce crystal loss. The filtering area can also be increased to improve the filtering efficiency and processing capacity. Deep filtration can be achieved through layers of filter cloth 80 with different pore sizes to reduce the clogging problem of the filter cloth 80, thereby providing a higher quality filtering effect.

[0047] It should be noted that in other embodiments, the separation box 40 may also be disposed on the right side of the filter box 30 , and accordingly, the roller 50 drives the filter cloth 80 to circulate clockwise so that the filter cloth 80 passing through the filter box 30 enters the separation box 40 .

[0048] like Figure 3 , Figure 4 , Figure 6 and Figure 7As shown, the pressing roller 520, the supporting roller 530 and the guide roller 540 are rotatably installed in the separation box 40 respectively. The left part of the three-layer filter cloth 80 passes through the separation box 40, and the part of the three-layer filter cloth 80 entering the separation box 40 is located between the pressing roller 520 and the supporting roller 530. The two supporting rollers 530 support the three-layer filter cloth 80 upward. The pressing roller 520 is connected to the output end of the squeezing motor 521 to rotate under the drive of the squeezing motor 521 to squeeze the part of the three-layer filter cloth 80 located between the two supporting rollers 530, so that the moisture on the filter cloth 80 is separated from the intercepted solid crystals, which assists the drying of the solid crystals and is conducive to the separation of the solid crystals from the filter cloth 80. The separation box 40 is provided with a receiving groove 430 located below the two rollers 530. The lower end of the receiving groove 430 is connected to the liquid guide tube 440. The end of the liquid guide tube 440 that is away from the receiving groove 430 extends into the lower end of the filter box 30 to introduce the squeezed water into the filter box 30 and discharge it together with the mother liquor after secondary filtration. One of the rollers 50 is arranged in the separation box 40 and is located at the place where the three layers of filter cloth 80 leave the separation box 40. There are two pairs of guide rollers 540 and they are located at the left side of the separation box 40. The filter cloths 80 other than the innermost layer of filter cloth 80 are respectively wound on the paired guide rollers 540, so that the three layers of filter cloth 80 enter the separated state from the overlapping state and remain parallel to each other, so as to facilitate the separation operation of the solid crystals trapped on the front of each layer of filter cloth 80.

[0049] like Figure 1 , Figure 3 , Figure 7 and Figure 8As shown, a bellows 630 is provided in the separation box 40, and an air extraction pipe 610 and an air supply pipe 620 are provided on the air pump 60. The end of the air extraction pipe 610 away from the air pump 60 is connected to the lower part of the filter box 30 to extract air from the lower part of the filter box 30, so as to increase the pressure difference between the upper and lower sides of the three layers of filter cloth 80 in the filter box 30, thereby pushing the mother liquid through the multiple layers of filter cloth 80. The end of the air supply pipe 620 away from the air pump 60 is connected to the bellows 630 to pass gas into the bellows 630. A bronchial pipe 640 corresponding to each layer of filter cloth 80 is provided on the side of the bellows 630 away from the air supply pipe 620, and a plurality of nozzles 650 are installed on each bronchial pipe 640, and the nozzles 650 face the reverse side of each layer of filter cloth 80 to spray the solid crystals attached to the front side of each layer of filter cloth 80, so as to separate the solid crystals from each layer of filter cloth 80 and further assist in drying the solid crystals. In this way, continuous filtration of the secondary filtration is achieved, and each layer of filter cloth 80 is cleaned online. An air guide 660 is provided between the upper end of the separation box 40 and the coarse filter box 20, and one end of the air guide 660 away from the separation box 40 extends into the material guide trough 250 to blow the solid crystals in the material guide trough 250 to prevent the solid crystals from accumulating and staying in the material guide trough 250, while keeping the air pressure of the cavity connecting the coarse filter box 20 and the filter box 30 stable, realizing the circulation of gas, reducing the entry of external air, and preventing dust and impurities carried by the external air from affecting the purity of the separated crystals.

[0050] like Figure 4 , Figure 6 and Figure 7 As shown, the separation box 40 is fixed with a limiting frame 410 corresponding to each layer of filter cloth 80. Each limiting frame 410 extends forward and backward and is located on the reverse side of the corresponding filter cloth 80. Each limiting frame 410 has a limiting groove for passing the filter cloth 80 to limit each layer of filter cloth 80, so as to prevent the filter cloth 80 from shaking too much when the nozzle 650 sprays the filter cloth 80, thereby affecting the material receiving effect of the material guide film 420. The limiting frames 410 other than the innermost limiting frame 410 are located between the front and back sides of two adjacent filter cloths 80, and are installed with a material guide film 420. The front and rear ends of the material guide film 420 are fixed on the limiting frame 410, which is used to receive the solid crystals blown off the filter cloth 80 on the right side of the material guide film 420, and shake up and down when sprayed by the nozzle 650, so as to prevent the solid crystals from adhering to the material guide film 420, which is conducive to the transportation of the solid crystals. After being blown off by the nozzle 650, the solid crystals on the leftmost filter cloth 80 directly fall onto the inner bottom surface of the separation box 40. The inner bottom surface of the separation box 40 has a material guide slope toward the discharge trough 130, the lowest point of the separation box 40 is connected to the discharge trough 130, and the material guide film 420 has a material guide slope toward the discharge trough 130, so that the automatic collection of solid crystals with smaller particle size is realized, manual operation is reduced, and the collection efficiency is improved.

[0051] like Figures 1 to 3As shown, the bottom end of the buffer box 70 is fixedly installed in the box shell 10 through a bracket 720, the lower end of the buffer box 70 is connected to the liquid outlet pipe 140 arranged outside the box shell 10, and a connecting pipe 710 is arranged between the buffer box 70 and the lower end of the filter box 30. The buffer box 70 is used to cache the mother liquid after filtration, and can isolate the liquid outlet end of the filter box 30 from the outside, preventing dust and impurities carried by the outside air from entering the filter box 30, which is conducive to ensuring the purity of the crystal.

[0052] The present invention also provides a multi-stage filtration process for crystallization of chemical raw materials, comprising the following steps:

[0053] The first step is to add materials, and pour the mother liquor containing solid crystals into the coarse filter box 20 through the liquid inlet pipe 110.

[0054] In the second step, preliminary filtration, the mother liquor containing solid crystals flows to the top of the bulk cap 210 through the liquid inlet pipe 110, and disperses to the inner wall of the coarse filter box 20 along the conical side wall of the bulk cap 210, so that the mother liquor containing solid crystals is evenly dispersed on the filter screen 230 and passes through the filter screen 230, and the solid crystals with larger particle size are retained on the upper surface of the filter screen 230. The mother liquor after preliminary filtration flows into the filter box 30 through the filter screen 230.

[0055] The third step is preliminary separation. The push motor 221 drives the rotating shaft 260 to drive the push plate 220 to rotate. The push plate 220 pushes the solid crystals with larger particle size on the upper surface of the filter screen 230 toward the inner wall of the coarse filter box 20. The solid crystals with larger particle size fall into the guide trough 250 and then enter the coarse material trough 120 for discharge.

[0056] The fourth step is secondary filtration. The circulating motor 510 drives one of the rollers 50 to rotate, and the roller 50 drives the three-layer filter cloth 80 to circulate along a closed loop path. The three-layer filter cloth 80 passes through the filter box 30 to perform secondary filtration on the mother liquor after the preliminary filtration. The air pump 60 draws air to the lower part of the filter box 30 through the exhaust pipe 610 to push the mother liquor through the three-layer filter cloth 80. Solid crystals with smaller particle sizes are trapped on the front side of each layer of filter cloth 80. The mother liquor after the secondary filtration passes through the three-layer filter cloth 80 and enters the buffer box 70.

[0057] The fifth step is secondary separation. The three layers of filter cloth 80 are moved from the filter box 30 to the separation box 40. The air pump 60 supplies air to the nozzle 650 through the air supply pipe 620. The nozzle 650 sprays the back side of each layer of filter cloth 80 to separate the solid crystals with smaller particle size on the front side of each layer of filter cloth 80 from each layer of filter cloth 80 and fall on the guide membrane 420 or the inner bottom surface of the separation box 40, and then enter the discharge trough 130 for discharge.

[0058] In this way, the mother liquor containing solid crystals is filtered by a multi-stage filtration method. First, solid crystals with larger particle sizes are separated by preliminary filtration, and then solid crystals with smaller particle sizes are separated by secondary filtration. This not only optimizes the particle size distribution to meet the needs of different applications, but also reduces the burden of secondary filtration and improves the filtration efficiency. The secondary filtration uses multiple layers of filter cloth 80, which can more effectively intercept solid crystals with smaller particle sizes to improve the filtration accuracy and reduce crystal loss. It can also increase the filtration area to improve the filtration efficiency and processing capacity, and can achieve deep filtration through layers of filter cloth 80 with different pore sizes to reduce the clogging problem of the filter cloth 80, thereby providing a higher quality filtration effect. Moreover, both the preliminary filtration and the secondary filtration achieve continuous filtration, allowing the mother liquor to flow continuously in the filter box 30, reducing downtime and improving production efficiency. The filter cloth 80 can be cleaned online to avoid the accumulation of solid crystals on the surface of the filter cloth 80, keeping the filtration channel unobstructed, and further improving the filtration efficiency.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 limiting the present invention.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A multi-stage filtration device for crystallization of chemical raw materials, comprising a housing provided with a liquid inlet pipe and a material outlet trough, characterized in that: Also includes: The filter box is arranged in the box shell, and the upper end of the filter box is connected with the liquid inlet pipe; The separation box is arranged in the box shell and is located on the left side of the filter box. The lower end of the separation box is connected to the discharge trough. A nozzle and a material guide membrane are arranged in the separation box. The material guide membrane has a material guide slope toward the discharge trough. Rollers, multiple rollers are rotatably installed in the box shell; Filter cloth, the filter cloth is wound around multiple rollers in a closed loop, so as to move counterclockwise under the drive of the rollers. The filter cloth is stacked in multiple layers, and the pore size of the filter cloth gradually decreases from the outer layer to the inner layer. The upper part of the multiple layers of filter cloth passes through the filter box to filter the mother liquid, and the left part of the multiple layers of filter cloth passes through the separation box. The nozzle faces the reverse side of each layer of filter cloth to spray the solid crystals attached to the front side of each layer of filter cloth. The guide membrane is arranged on the front side of each layer of filter cloth to receive the blown-off solid crystals. An air pump is installed outside the box shell, and is provided with an air extraction pipe connected to the lower part of the filter box and an air supply pipe connected to the nozzle; A pressure roller and an idler roller are rotatably installed in the separation box. The part of the multi-layer filter cloth entering the separation box is located between the pressure roller and the idler roller. The two idlers support the multi-layer filter cloth upward, and the pressure roller squeezes the part of the multi-layer filter cloth located between the two idlers. A receiving groove is arranged under the two idlers. The lower end of the receiving groove is connected to the liquid guiding pipe. The end of the liquid guiding pipe away from the receiving groove extends into the lower end of the filter box. An extrusion motor for driving the pressure roller to rotate and a circulation motor for driving the rotating roller to rotate are arranged on the box shell.

2. A multi-stage filtration device for crystallization of chemical raw materials according to claim 1, characterized in that: A coarse filter box located above the filter box and connected to the filter box is also provided in the box shell. A filter screen is provided in the coarse filter box. A push plate is rotatably installed on the upper surface of the filter screen. The liquid inlet pipe extends from the side wall of the box shell to the top of the filter screen. A material guide groove is provided between the outer peripheral side of the filter screen and the inner wall of the coarse filter box. The lower end of the material guide groove is connected to the coarse material groove outside the box shell. A pushing motor for driving the pushing plate to rotate is provided on the box shell.

3. A multi-stage filtration device for crystallization of chemical raw materials according to claim 2, characterized in that: A bulk material cap is arranged in the coarse filter box between the liquid inlet pipe and the push plate. The bulk material cap is in the shape of a cone with a gradually narrowing upper end. A plurality of bulk material holes are provided on the bulk material cap. The filter screen is in the shape of a cone with a gradually narrowing lower end. The push plate is vortex-shaped, and the material guide trough has a material guide slope toward the coarse material trough.

4. A multi-stage filtration device for crystallization of chemical raw materials according to claim 1, characterized in that: Paired guide rollers are rotatably installed in the separation box, and filter cloths other than the innermost filter cloth are respectively wound on the paired guide rollers.

5. A multi-stage filtration device for crystallization of chemical raw materials according to claim 2, characterized in that: A bellows is provided in the separation box. The end of the air supply pipe facing away from the air pump is connected to the bellows. Bronchial pipes corresponding to each layer of filter cloth are provided on the side of the bellows facing away from the air supply pipe. Multiple nozzles are installed on each bronchial pipe. An air guide pipe is provided between the upper end of the separation box and the coarse filter box. The end of the air guide pipe facing away from the separation box extends into the material guide trough.

6. A multi-stage filtration device for crystallization of chemical raw materials according to claim 1, characterized in that: A limiting frame corresponding to each layer of filter cloth is fixed in the separation box, each limiting frame extends forward and backward and is located on the reverse side of the corresponding filter cloth, and each limiting frame has a limiting groove for passing the filter cloth.

7. A multi-stage filtration device for crystallization of chemical raw materials according to claim 6, characterized in that: The limiting frames except the innermost limiting frame are located between the front and back surfaces of two adjacent filter cloths and are provided with material guiding films, the front and rear ends of which are fixed on the limiting frames.

8. A multi-stage filtration device for crystallization of chemical raw materials according to claim 1, characterized in that: A cache box located below the filter box is also provided in the box shell, a connecting pipe is provided between the lower ends of the cache box and the filter box, and the cache box is connected to a liquid outlet pipe provided outside the box shell.

9. A multi-stage filtration process for crystallization of chemical raw materials, characterized in that: A multi-stage filtration device for crystallization of chemical raw materials according to claim 1, comprising the following steps: The first step is to add materials, and pour the mother liquor containing solid crystals into the filter box through the liquid inlet pipe; The second step is filtration. The roller drives the multi-layer filter cloth to circulate along a closed loop path. The multi-layer filter cloth passes through the filter box to filter the mother liquid containing solid crystals. The air pump draws air to the lower part of the filter box through the suction pipe to push the mother liquid through the multi-layer filter cloth. The solid crystals are trapped on the front of each layer of filter cloth. The third step is separation. The multiple layers of filter cloth are moved from the filter box to the separation box. The air pump supplies air to the nozzle through the air supply pipe. The nozzle blows on the back of each layer of filter cloth, so that the solid crystals on the front of each layer of filter cloth are separated from the filter cloth and fall on the material guide membrane. The material guide membrane guides the solid crystals into the discharge trough for discharge.

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