阅读说明：本技术 一种四氯苯酐生产中氯磺酸的回收工艺 (Process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production ) 是由 陈钢 秦锡荣 宋凤英 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种四氯苯酐生产中氯磺酸的回收工艺,涉及四氯苯酐生产的技术领域,包括以下工艺步骤：S1：当四氯苯酐半成品悬浮液从主水洗釜进入水洗釜前,先干燥水洗釜和氯磺酸回收管道；S2：当四氯苯酐半成品悬浮液从主水洗釜全部进入水洗釜后,往水洗釜内通入压缩空气,将溶剂通过回收管道排入氯磺酸计量槽内；S3：向氯磺酸计量槽内补充纯氯磺酸,然后回用至吸收釜内；本发明具有提高氯磺酸回收率的优点。(The invention discloses a process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production, which relates to the technical field of tetrachlorophthalic anhydride production and comprises the following process steps: s1: before the tetrachlorophthalic anhydride semi-finished product suspension enters the washing kettle from the main washing kettle, the washing kettle and the chlorosulfonic acid recovery pipeline are dried; s2: when the tetrachlorophthalic anhydride semi-finished product suspension completely enters the water washing kettle from the main water washing kettle, introducing compressed air into the water washing kettle, and discharging the solvent into a chlorosulfonic acid metering tank through a recovery pipeline; s3: supplementing pure chlorosulfonic acid into the chlorosulfonic acid metering tank, and then recycling the chlorosulfonic acid into the absorption kettle; the invention has the advantage of improving the recovery rate of chlorosulfonic acid.)

1. A process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production is characterized by comprising the following process steps:

s1: before the tetrachlorophthalic anhydride semi-finished product suspension enters the washing kettle from the main washing kettle, the washing kettle and the chlorosulfonic acid recovery pipeline are dried;

s2: when the tetrachlorophthalic anhydride semi-finished product suspension completely enters the water washing kettle from the main water washing kettle, introducing compressed air into the water washing kettle, and discharging the solvent into a chlorosulfonic acid metering tank through a recovery pipeline;

s3: supplementing pure chlorosulfonic acid into the chlorosulfonic acid metering tank, and then recycling the chlorosulfonic acid into the absorption kettle;

the one end that recovery pipeline and chlorosulfonic acid metering tank link to each other is provided with the branch pipe, the branch pipe is linked together through desicator and washing cauldron, still install circulating air pump on the branch pipe, the last control valve who is provided with control recovery pipeline and branch pipe switching of recovery pipeline.

2. The recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: the dryer is internally provided with a drying agent, and the drying agent comprises the following components in parts by weight:

3. the recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: the inner surface of the recovery pipeline is coated with a layer of isolation layer, and the isolation layer comprises the following components in parts by weight:

4. the recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: there is recovery pipeline (110), its characterized in that through flange joint on washing cauldron (100): one end of the recovery pipeline (110) extends into the washing kettle (100), the other end of the recovery pipeline is connected with a collecting pipe (120) through a flange, a first filter screen (130) is detachably connected to one end port of the recovery pipeline (110) extending into the washing kettle (100), a plurality of through holes are formed in the side wall of one end of the recovery pipeline (110) extending into the washing kettle (100), a connecting piece (200) is detachably connected to the side wall of one end of the recovery pipeline (110) extending into the washing kettle (100), a second filter screen (210) is installed in the connecting piece (200), and the aperture of the second filter screen (210) is smaller than that of the through holes;

install first framework (140) outward first filter screen (130), first framework (140) are hollow cylinder, the outer circumference of first framework (140) has protruding (150) along radial outside protrusion, recovery duct (110) tip seted up along the axial with protruding (150) complex spout (160), the end of spout (160) is followed recovery duct (110) circumference seted up with protruding (150) joint complex joint groove (170).

5. The recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: the connecting piece (200) comprises a first connecting portion (201) and a second connecting portion (202), the first connecting portion (201) and the second connecting portion (202) are installed at two ends of the second filter screen (210) which are axially arranged along the recovery pipeline (110), the first connecting portion (201) and the second connecting portion (202) are in an open circular ring shape, an annular groove (204) used for installing the second filter screen (210) is inwards formed in the end face of the first connecting portion (201) and the second connecting portion (202) which is axially arranged along the recovery pipeline (110), and locking pieces (220) used for closing the open ends are arranged at two ends of the first connecting portion (201) and the second connecting portion (202) which are circumferentially arranged;

the locking piece (220) comprises a bending part (221), a bolt (222) and a nut (223), the bending part (221) is arranged at two ends of the first connecting part (201) and the second connecting part (202) which are arranged along the circumferential direction, a threaded hole is formed in the bending part (221) in a penetrating mode, and the bolt (222) sequentially penetrates through the threaded hole and is connected with the nut (223);

guide arc surfaces (205) are arranged on two sides of the port of the annular groove (204) on the first connecting portion (201) and the second connecting portion (202).

6. The recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: the first connecting part (201) and the second connecting part (202) are provided with pressing pieces (230) used for tightly pressing the second filter screen (210), the pressing piece (230) comprises a rotating shaft (231), a convex block (232), an abutting rod (233) and a spring (234), the end faces of the two ends of the first connecting part (201) and the second connecting part (202) which are arranged along the circumferential direction are inwards provided with a cavity (235), one end of the rotating shaft (231) extends into the chamber (235), the lug (232) is arranged at one end of the rotating shaft (231) extending into the chamber (235), the side wall of the chamber (235) is provided with a through hole communicated with the annular groove (204), one end of the abutting rod (233) abuts against the lug (232), the other end of the abutting rod extends into the annular groove (204), and the spring (234) is sleeved outside the abutting rod (233);

the end part of one end, extending into the annular groove (204), of the abutting rod (233) is an arc surface attached to the wall of the annular groove (204).

7. The recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 5, wherein the process comprises the following steps: the recycling pipeline (110) stretches into one end in the washing kettle (100) is provided with an annular bulge (180) along the circumferential direction, and the inner walls of the first connecting part (201) and the second connecting part (202) are inwards provided with an annular groove (203) matched with the annular bulge (180).

8. The recovery process of chlorosulfonic acid in tetrachlorophthalic anhydride production according to claim 1, which is characterized in that: the drying and washing kettle and the chlorosulfonic acid recovery pipeline in the step S1 specifically comprise the following steps:

step 1: firstly, adjusting a control valve, opening a branch pipe, closing a recovery pipeline, and opening a circulating air pump for circulating drying;

step 2: and after the washing kettle and the recovery pipeline are dried, stopping the circulating pump, and adjusting the control valve to open the recovery pipeline and close the branch pipe.

Technical Field

The invention relates to the technical field of tetrachloroaniline production, in particular to a process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production.

Background

Tetrachlorophthalic anhydride is also an organic synthetic intermediate of pesticide (isoprothiolane), phthalocyanine green pigment, xanthene dye, medicine, plasticizer, fireproof paint and the like.

The prior tetrachlorophthalic anhydride production process, as disclosed in the Chinese patent with the publication number of CN102079734A, discloses a circular economy comprehensive treatment method for preparing tetrachlorophthalic anhydride, which comprises several key parts: firstly, phthalic anhydride is in a chlorosulfonic acid solvent, iodine is used as a catalyst, tetrachlorophthalic anhydride is synthesized in a high selectivity manner through precise control, and the minimization of the generation amount of hexachlorobenzene and the recycling of chlorosulfonic acid are realized; secondly, after the hydrogen chloride gas containing chlorine as a byproduct is subjected to multistage absorption and recovery of hydrogen chloride and concentrated hydrochloric acid as a byproduct, the chlorine-containing tail gas is absorbed by ferrous chloride waste liquid as a byproduct of acid cleaning and rust removal of peripheral steel processing enterprises to obtain a ferric chloride solution which is used as a waste water flocculant for printed circuit board etching or printing and dyeing enterprises, so that wastes of the two enterprises are converted into products with higher added values, and the resource utilization of the wastes and the efficient utilization of chlorine elements are realized; thirdly, the dilute hydrochloric acid-sulfuric acid solution containing the organic chloride is catalyzed and oxidized to remove most of the organic chloride, the quality of the waste hydrochloric acid-sulfuric acid is improved, the acidity is increased through a tail gas absorption system, and the waste hydrochloric acid-sulfuric acid solution is reused for acid cleaning and rust removal in steel processing, so that resource utilization is realized.

The above prior art solutions have the following drawbacks: chlorosulfonic acid is used as the solvent in the tetrachlorophthalic anhydride production process and the use amount is very big, and the enterprise can retrieve chlorosulfonic acid for use, but in the prior art, direct extraction separation mode is adopted for the retrieval and utilization of chlorosulfonic acid, and because the steam residue in the previous separation washing process in the washing kettle of separation tetrachlorophthalic anhydride and chlorosulfonic acid makes partial hydrolysis of chlorosulfonic acid, and produces more hydrochloric acid and sulfuric acid, makes the retrieval and utilization benefit of chlorosulfonic acid decline.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production, wherein the recovery efficiency of chlorosulfonic acid is further improved by arranging a branch pipe and a dryer.

The above object of the present invention is achieved by the following technical solutions:

a process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production comprises the following process steps:

s1: before the tetrachlorophthalic anhydride semi-finished product suspension enters the washing kettle from the main washing kettle, the washing kettle and the chlorosulfonic acid recovery pipeline are dried;

s2: when the tetrachlorophthalic anhydride semi-finished product suspension completely enters the water washing kettle from the main water washing kettle, introducing compressed air into the water washing kettle, and discharging the solvent into a chlorosulfonic acid metering tank through a recovery pipeline;

s3: supplementing pure chlorosulfonic acid into the chlorosulfonic acid metering tank, and then recycling the chlorosulfonic acid into the absorption kettle;

the one end that recovery pipeline and chlorosulfonic acid metering tank link to each other is provided with the branch pipe, the branch pipe is linked together through desicator and washing cauldron, still install circulating air pump on the branch pipe, the last control valve who is provided with control recovery pipeline and branch pipe switching of recovery pipeline.

By adopting the technical scheme, chlorosulfonic acid can be recycled and applied mechanically through the recovery pipe, and the recovery rate of resources is greatly improved. And meanwhile, the branch pipe and the dryer are arranged, so that the pipeline and the air in the kettle can be completely dried before the next feeding of the water washing kettle, the loss caused by the reaction between the chlorosulfonic acid solvent and water is reduced, and the recovery rate of chlorosulfonic acid is improved to a greater extent.

The invention is further configured to: the dryer is internally provided with a drying agent, and the drying agent comprises the following components in parts by weight:

by adopting the technical scheme, the montmorillonite is a layered mineral composed of the extremely fine-particle hydrous aluminosilicate, has better adsorption performance, the zinc chloride has stronger hygroscopicity, the two forms a multilayer drying film in the dryer under the action of the silica gel and the cationic film-forming agent, and after air passes through the dryer, water molecules can be physically adsorbed by the montmorillonite and further absorbed by the zinc chloride for hydration and deliquescence, so that the air is dried more efficiently. Meanwhile, the cationic film forming agent and the silica gel are utilized, so that the drying agent absorbing water molecules is not easy to diffuse along with air to pollute equipment.

The invention is further configured to: the inner surface of the recovery pipeline is coated with a layer of isolation layer, and the isolation layer comprises the following components in parts by weight:

by adopting the technical scheme, the fluorine-containing silane coupling agent dodecafluoroheptyl propyl trimethoxy silicon is utilized to carry out surface treatment on the aluminum oxide particles to obtain nano particles with surface fluorine modification as pigment filler, the obtained nano particles are dispersed in the fluorine hydroxyl acrylic resin, and the super hydrophobic-oleophobic coating is prepared in an air spraying mode, so that when sewage flows in the inner pipe, the sewage is smoother, and the ionic through holes on the side wall of the inner pipe are not easy to block.

The invention is further configured to: have the recovery pipeline through flange joint on the washing cauldron, recovery pipeline one end stretches into in the washing cauldron, the other end has the collecting pipe through flange joint, the recovery pipeline stretches into one end port department in the washing cauldron can dismantle and be connected with first filter screen, the recovery pipeline stretches into a plurality of through-holes have been seted up on the one end lateral wall in the washing cauldron, the recovery pipeline stretches into can dismantle on the one end lateral wall in the washing cauldron and be connected with the connecting piece, install the second filter screen in the connecting piece, the aperture of second filter screen is less than the aperture of through-hole.

Install first framework outward first filter screen, first framework is hollow cylinder, the outer circumference of first framework has the arch along radial outside protrusion, the recovery pipeline tip along the axial seted up with protruding complex spout, the end of spout along recovery pipeline circumference seted up with protruding joint complex joint groove.

Through adopting above-mentioned technical scheme, when needs retrieve chlorosulfonic acid in to the washing cauldron, retrieve and transport to the collecting tube through the chlorosulfonic acid that the recovery pipeline will generate in the washing cauldron, play the effect of holding back to tetrachlorophthalic anhydride at the in-process first filter screen and the second filter screen of retrieving chlorosulfonic acid for the in-process that retrieves chlorosulfonic acid reduces the amount of tetrachlorophthalic anhydride loss. The through holes on the side wall of the recovery pipeline play a role in increasing the effective recovery area of the chlorosulfonic acid, and the arrangement that the aperture of the second filter screen is smaller than that of the through holes enables the effective recovery area of the chlorosulfonic acid to be increased while the loss of tetrachlorophthalic anhydride entering the through holes to be reduced

The setting up of first framework makes things convenient for first filter screen to install and dismantle work in the recovery pipeline, when carrying out the installation work of first framework on the recovery pipeline, aligns the spout of recovery pipeline tip with the arch outside the first framework and takes place to slide along the spout, and protruding slip in the first framework is to the recovery pipeline end back, with first framework circumferential direction, protruding further joint gets into the joint inslot and realizes fixed to first framework.

The invention is further configured to: the connecting piece includes first connecting portion and second connecting portion, first connecting portion with the second connecting portion are installed the second filter screen is followed the both ends that the recovery pipeline axial set up, first connecting portion with the second connecting portion are the open-ended ring form, first connecting portion with the second connecting portion are followed the terminal surface that the recovery pipeline axial set up is inwards offered and is used for the installation the ring channel of second filter screen, first connecting portion with the both ends that the second connecting portion set up along circumference are provided with and are used for sealing open-ended retaining member.

The retaining member is including the portion of bending, bolt and nut, the portion of bending sets up first connecting portion with the both ends that the second connecting portion set up along circumference, it is provided with the screw hole to run through in the portion of bending, the bolt pass in proper order the screw hole and with the nut is connected.

And guide arc surfaces are arranged on two sides of the port of the annular groove on the first connecting part and the second connecting part.

By adopting the technical scheme, the arrangement of the annular grooves on the first connecting part and the second connecting part plays a role in mounting the second filter screen; simultaneously first connecting portion and second connecting portion play the connection effect to the second filter screen both ends to compress tightly first connecting portion and second connecting portion on the recovery pipeline through the retaining member, realize the installation and the dismantlement of first connecting portion and second connecting portion on the recovery pipeline. The first connecting portion and the second connecting portion sequentially penetrate through threaded holes in the bending portion through bolts to be connected to a recycling pipeline, and the first connecting portion and the second connecting portion are convenient to install and detach.

When the installation work of the second filter screen on the first connecting portion and the second connecting portion is carried out, the arrangement of the guide cambered surface facilitates the clamping of the second filter screen into the annular groove on the first connecting portion and the second connecting portion.

The invention is further configured to: be provided with on first connecting portion and the second connecting portion and be used for supporting tightly the piece that compresses tightly of second filter screen, it includes axis of rotation, lug, butt joint pole and spring to compress tightly the piece, first connecting portion with the both ends terminal surface that the second connecting portion set up along circumference has inwards seted up the cavity, axis of rotation one end stretches into in the cavity, the lug is installed the axis of rotation stretches into one end in the cavity, seted up on the cavity lateral wall with the perforation of ring channel intercommunication, butt pole one end with lug butt, the other end stretch into the ring channel, the spring housing is established outside the butt joint pole. And the end part of one end of the abutting rod extending into the annular groove is an arc surface attached to the wall of the annular groove.

Through adopting above-mentioned technical scheme, the setting that compresses tightly the piece plays the effect that compresses tightly to the second filter screen for the lateral wall of ring channel is hugged closely to the second filter screen, reduces the possibility that the second filter screen during operation takes place the displacement in the ring channel. After in installing the ring channel with the second filter screen, rotate the axis of rotation, the axis of rotation further drives the lug and takes place to rotate, and the lug is because its surface is different to axis of rotation axis line distance, and the effect butt lug of butt rod because the spring simultaneously, consequently the lug takes place to promote the butt rod to take place the displacement after rotating, stretches into in the ring channel and butt second filter screen until butt rod tip for the second filter screen supports tightly on the ring channel inner wall.

Because the ring channel has certain radian, consequently when supporting the second filter screen tightly to the lateral wall of ring channel on, the setting of butt rod tip cambered surface has increased the area of contact of butt rod tip with the second filter screen in comparison with the plane, and the better laminating ring channel lateral wall when supporting tight state reduces the damage to the second filter screen.

The invention is further configured to: the recovery pipeline stretches into one end in the washing cauldron is provided with annular protrusion along circumference, first connecting portion with second connecting portion inner wall inwards seted up with annular protrusion complex annular.

Through adopting above-mentioned technical scheme, annular protruding cooperation on recovery pipeline and the annular on first connecting portion, the second connecting portion for first connecting portion and second connecting portion receive annular protruding spacing, are difficult for taking place the displacement along the recovery pipeline axial.

The invention is further configured to: the drying and washing kettle and the chlorosulfonic acid recovery pipeline in the step S1 specifically comprise the following steps:

step 1: firstly, adjusting a control valve, opening a branch pipe, closing a recovery pipeline, and opening a circulating air pump for circulating drying;

step 2: and after the washing kettle and the recovery pipeline are dried, stopping the circulating pump, and adjusting the control valve to open the recovery pipeline and close the branch pipe.

Compared with the prior art, the invention has the beneficial effects that:

1. the influence of moist air and water vapor on the recovery of chlorosulfonic acid in the tetrachlorophthalic anhydride at the next time is avoided by thoroughly drying the washing kettle after the tetrachlorophthalic anhydride product is separated every time;

2. through the arrangement of the first filter screen and the second filter screen, the tetrachlorophthalic anhydride is retained in the reaction kettle while the effective recovery area of chlorosulfonic acid is ensured, so that the loss of tetrachlorophthalic anhydride caused by chlorosulfonic acid recovery is reduced;

3. the cooperation of annular arch and annular for first connecting portion and second connecting portion are difficult for taking place to slide along the recovery tube axial, guarantee that the second filter screen acts on the region of seting up the through-hole on the recovery tube all the time.

Drawings

FIG. 1 is a schematic structural view of the whole of this embodiment, showing the structure of the inside of a water washing tank;

FIG. 2 is a schematic illustration of an exploded view of the recovery pipe of FIG. 1 showing the mounting arrangement at the first screen;

FIG. 3 is a schematic view of an exploded structure at a connection of FIG. 1, showing a mounting structure of a second screen at the connection;

fig. 4 is a cross-sectional view of the first connecting portion of fig. 1 in a horizontal direction; showing the mounting arrangement at the compression member;

fig. 5 is a partially enlarged schematic view of a portion a in fig. 4.

In the figure, 100, a water washing kettle; 110. a recovery pipeline; 120. a collection pipe; 130. a first filter screen; 140. a first frame body; 150. a protrusion; 160. a chute; 170. a clamping groove; 180. an annular projection; 200. a connecting member; 201. a first connection portion; 202. a second connecting portion; 203. a ring groove; 204. an annular groove; 205. guiding the arc surface; 210. a second filter screen; 220. a locking member; 221. a bending part; 222. a bolt; 223. a nut; 230. a compression member; 231. a rotating shaft; 232. a bump; 233. a butting rod; 234. a spring; 235. a chamber; 236. a baffle plate; 237. a baffle ring; 238. an arc-shaped block.

Detailed Description

The present invention will be described in detail with reference to examples.

The invention discloses a process for recovering chlorosulfonic acid in tetrachlorophthalic anhydride production, which comprises the following process steps:

s1: before the tetrachlorophthalic anhydride semi-finished product suspension enters the washing kettle from the main washing kettle, the washing kettle and the chlorosulfonic acid recovery pipeline are dried; the specific drying steps are as follows:

step 1: firstly, adjusting a control valve, opening a branch pipe, closing a recovery pipeline, and opening a circulating air pump for circulating drying;

step 2: and after the washing kettle and the recovery pipeline are dried, stopping the circulating pump, and adjusting the control valve to open the recovery pipeline and close the branch pipe.

S2: when the tetrachlorophthalic anhydride semi-finished product suspension completely enters the water washing kettle from the main water washing kettle, introducing compressed air into the water washing kettle, and discharging the solvent into a chlorosulfonic acid metering tank through a recovery pipeline;

s3: supplementing pure chlorosulfonic acid into the chlorosulfonic acid metering tank, and then recycling the chlorosulfonic acid into the absorption kettle;

the end that the recovery pipeline links to each other with chlorosulfonic acid metering tank is provided with the branch pipe, and the branch pipe is linked together through desicator and washing cauldron, still installs circulating air pump on the branch pipe, is provided with the control valve of control recovery pipeline and branch pipe switching on the recovery pipeline.

A drying agent is arranged in the dryer and comprises the following components in parts by weight:

the cationic film forming agent is cationic acrylic resin.

The inner surface of the recovery pipeline is coated with a layer of isolation layer, and the isolation layer comprises the following components in parts by weight:

the coating process of the release layer is as follows: firstly, soaking micron aluminum oxide and nano silicon dioxide in dodecafluoroheptyl propyl trimethoxy silane for treatment for 10 minutes, then uniformly stirring and mixing the treated micron aluminum oxide and nano silicon dioxide with fluoro hydroxy acrylic resin and tetraethoxysilane, and finally coating the inner tube with the mixed solution by using a centrifugal casting machine.

Referring to fig. 1, a recovery pipe 110 is connected to the top end of the water washing kettle 100 through a flange, one end of the recovery pipe 110 extends into the water washing kettle 100, and a collecting pipe 120 for collecting and transporting chlorosulfonic acid is connected to one end of the recovery pipe 110 located outside the water washing kettle 100 through a flange.

Referring to fig. 2, a first filter screen 130 is detachably connected to an end of the recycling pipe 110 extending into the water washing kettle 100, a first frame 140 is detachably connected to the outside of the first filter screen 130, the first frame 140 is hollow cylindrical, two protrusions 150 are formed on the outer circumference of the first frame 140 and protrude outwards in the radial direction, and the two protrusions 150 are symmetrically arranged along the axis of the first frame 140. The inner wall of the end of the recovery pipe 110 is axially provided with a chute 160 matching with the protrusion 150, the end of the chute 160 is circumferentially provided with a clamping groove 170 matching with the protrusion 150 in a clamping manner, and the first filter screen 130 is mounted at one end of the first frame 140 far away from the port of the recovery pipe 110.

Referring to fig. 3, one end of the recovery pipeline 110 extending into the washing kettle 100 (see fig. 1) is circumferentially provided with two annular protrusions 180, the annular protrusions 180 are axially provided with two along the recovery pipeline 110, a plurality of through holes are formed in the sidewall of the recovery pipeline 110 between the two annular protrusions 180 in a penetrating manner, a connecting piece 200 is detachably connected between the two annular protrusions 180, a second filter screen 210 is detachably connected in the connecting piece 200, and the aperture of the second filter screen 210 is smaller than that of the through holes.

The connecting piece 200 comprises a first connecting portion 201 and a second connecting portion 202, the first connecting portion 201 and the second connecting portion 202 are axially arranged along the recovery pipeline 110, the first connecting portion 201 is located above the second connecting portion 202, the first connecting portion 201 and the second connecting portion 202 are in an open circular ring shape, and a circular groove 203 matched with the circular protrusion 180 in a clamping mode is inwards formed in the inner walls of the first connecting portion 201 and the second connecting portion 202 along the circumferential direction. The end faces of the first connecting portion 201 and the second connecting portion 202, which are close to the through hole, are provided with an annular groove 204 for installing a second filter screen 210 inwards along the circumferential direction, guide arc faces 205 for guiding the second filter screen 210 to slide into the annular groove 204 are arranged on two sides of a port of the annular groove 204, and the second filter screen 210 enters the annular groove 204 of the first connecting portion 201 and the second connecting portion 202 through clamping.

Referring to fig. 3, both ends of the first connecting portion 201 and the second connecting portion 202 disposed along the circumferential direction are provided with a locker 220 for closing the opening, and the locker 220 includes a bent portion 221, a bolt 222, and a nut 223. The two ends of the opening of the first connecting portion 201 and the opening of the second connecting portion 202 are bent outwards to form a bent portion 221, a threaded hole matched with the bolt 222 is formed in the end face of the bent portion 221 in a penetrating mode, the bolt 222 sequentially penetrates through the threaded hole in the bent portion 221 and is connected with the nut 223, the first connecting portion 201 and the second connecting portion 202 are locked to the recovery pipeline 110, the two bent portions 221 on the first connecting portion 201 are in a mutually abutting state, and the two bent portions 221 on the second connecting portion 202 are in a mutually abutting state.

Referring to fig. 4 and 5, a pressing member 230 for tightly pressing the second filter screen 210 is disposed in the first connecting portion 201 and the second connecting portion 202, and the pressing member 230 includes a rotating shaft 231, a protrusion 232, an abutting rod 233, and a spring 234. The end faces of the two ends of the first connecting portion 201, which are provided with the bending portion 221, are inwardly provided with a cavity 235, the opening of the cavity 235 is in threaded connection with a baffle 236, the baffle 236 is provided with an opening through which the rotating shaft 231 passes, one end of the rotating shaft 231 extends into the cavity 235 and is rotatably connected to the inner wall of the cavity 235, one end of the rotating shaft 231, which is located on the end face of the first connecting portion 201, is radially provided with a straight groove (not shown in the figure), and the protruding block 232 is integrally formed at one end of the rotating shaft. A through hole communicated with the annular groove 204 is formed in the axial side wall of the cavity 235 perpendicular to the rotating shaft 231, the end part of one end, located in the cavity 235, of the abutting rod 233 is abutted to the projection 232, the abutting part of the abutting rod 233 and the projection 232 is fixedly connected with a blocking ring 237 larger than the diameter of the abutting rod 233, the spring 234 is sleeved outside the abutting rod 233, and two ends of the spring 234 are respectively abutted to the blocking ring 237 and the inner wall of the cavity 235. The other end of the abutting rod 233 is located in the through hole and fixedly connected with an arc-shaped block 238, and the end surface of the arc-shaped block 238 is an arc surface attached to the wall of the annular groove 204. The arrangement of the second connection portion 202 is the same as that of the first connection portion 201.

The implementation principle of the embodiment is as follows:

when the first filter screen 130 and the second filter screen 210 on the recovery pipeline 110 need to be replaced, the first frame body 140 is rotated along the circumferential direction of the recovery pipeline 110, and then the first frame body 140 is displaced along the axial direction of the recovery pipeline 110, so that the protrusions 150 on the first frame body 140 slide in the clamping grooves 170 and the sliding grooves 160 in sequence, thereby realizing the detachment work of the first frame body 140 on the recovery pipeline 110, and further replacing the first filter screen 130 on the first frame body 140.

Next, the nut 223 is loosened to unlock the bent portion 221 of the first connection portion 201 and the second connection portion 202, so that the first connection portion 201 and the second connection portion 202 are opened, and the first connection portion 201 and the second connection portion 202 are detached from the recovery pipe 110. Then, the rotating shaft 231 is rotated through the straight groove 2311, the longer end of the protruding block 232 is far away from the abutting rod 233, the end portion, provided with the arc-shaped block 238, of the abutting rod 233 is driven to leave the annular groove 204 by the elastic force generated by the reset of the spring 234, the abutting effect on the second filter screen 210 is relieved, and then the second filter screen 210 is detached from and replaced in the annular grooves 204 on the first connecting portion 201 and the second connecting portion 202.