Advanced treatment equipment for chemical industrial wastewater discharge
By designing a multi-layer stirring mechanism and an air flotation separation system, the problems of adsorbent sedimentation and increased suspended solids in chemical wastewater are solved, achieving uniform treatment and efficient separation of wastewater, ensuring effluent quality, and reducing treatment costs.
Patent Information
- Application Number
- CN202422764528.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-11-13
AI Technical Summary
In the deep treatment of chemical industrial wastewater, the adsorbent may settle at the bottom due to its weight, resulting in uneven distribution of substances between the upper and lower layers, increasing treatment costs, and increasing the content of suspended solids and organic matter in the effluent, reducing the treatment efficiency of the flotation equipment and making it impossible to meet discharge standards.
The system employs a multi-layer stirring mechanism and an air flotation separation system. Rotational motion is transmitted through the meshing of the first and second bevel gears. Combined with the design of scrapers and inclined plates, it achieves thorough stirring of wastewater and effective separation of impurities.
It effectively solves the problems of adsorbent precipitation and increased suspended solids, improves the uniformity and efficiency of wastewater treatment, ensures that the effluent quality meets the discharge standards, extends equipment life and reduces operating costs.
Smart Images
Figure CN223534907U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wastewater treatment technology, and in particular to advanced treatment equipment for wastewater discharge from the chemical industry. Background Technology
[0002] In the chemical reaction process of chemical production, a large amount of wastewater is generated. In order to ensure product quality and normal operation of equipment, it is necessary to clean production equipment, reaction vessels, pipelines, etc. In pesticide production enterprises, when changing product types or performing regular maintenance, production equipment needs to be rinsed with a large amount of water. These washing wastewaters contain pollutants such as residual pesticide components, organic solvents and surfactants.
[0003] In advanced treatment processes, wastewater has a complex composition, with different substances having varying densities, easily leading to water stratification. If the adsorbent is not thoroughly stirred after mixing with the wastewater, it may settle at the bottom due to its greater weight, resulting in uneven distribution of substances between the upper and lower layers of the wastewater, increasing treatment costs. During sedimentation, some foam or floating matter may also be generated. In some advanced treatment processes that combine sedimentation and flocculation sedimentation, after flocculation sedimentation, impurities and foam may appear on the surface. This foam may cover the water surface, preventing normal air-water exchange, leading to increased suspended solids and organic matter content in the effluent, reducing the treatment efficiency of the flotation equipment, and failing to guarantee that the effluent quality meets discharge standards. Utility Model Content
[0004] The main purpose of this invention is to provide a deep treatment device for chemical industrial wastewater discharge, which can effectively solve the problems that cause adsorbents to settle at the bottom due to their weight, uneven distribution of substances in the upper and lower layers of wastewater, increased treatment costs, increased suspended solids and organic matter content in the effluent, reduced treatment efficiency of the flotation equipment, and inability to guarantee that the effluent quality meets the discharge standards.
[0005] To achieve the above objectives, this utility model provides the following technical solution: a deep treatment device for chemical industrial wastewater discharge, including a treatment tank, wherein a multi-layer stirring mechanism is provided inside the treatment tank, and a first support plate is fixedly connected inside the treatment tank;
[0006] The multi-layer stirring mechanism includes: a first motor, two device boxes, and four second bevel gears. The front sidewall of the first motor is fixedly connected to the rear sidewall of the processing box. A first rotating rod is fixedly connected to the output end of the first motor. The front end of the first rotating rod is rotatably connected to the inner front sidewall of the processing box. A first fixing ring is fixedly connected to the outer side of the middle part of the first rotating rod. A stirring rod is fixedly connected to the outer side of each of the four first fixing rings. The two device boxes are located on the outer sides of the front and rear ends of the first rotating rod. The four second bevel gears are located on the left and right sides inside the two device boxes. A first bevel gear is fixedly connected to the front and rear ends of the first rotating rod. The two first bevel gears are located inside the device boxes. Each first bevel gear meshes with two second bevel gears. A first connecting rod is fixedly connected inside each second bevel gear. The other ends of the four first connecting rods are rotatably connected to the inner left sidewall of the processing box and the left sidewall of the first support plate.
[0007] Furthermore, three second fixing rings are fixedly connected to the outer side of each of the first connecting rods, four connecting plates are fixedly connected to the outer side of each of the second fixing rings, and an arc-shaped push plate is fixedly connected to the other side of each of the four connecting plates.
[0008] Furthermore, a connecting pipe is connected through the left side wall of the processing box, air flotation holes are opened on the bottom of both the front and rear sides of the processing box, a control panel is fixedly connected to the front side wall of the processing box, and a first guide plate is fixedly connected to the top of the first support plate.
[0009] Furthermore, a second guide plate is fixedly connected to the inside right side of the treatment box, a sewage outlet pipe is connected through the inside of the right side wall of the treatment box, a top box is connected to the top of the treatment box, and an inclined plate is fixedly connected to the inside right side wall of the top box.
[0010] Furthermore, a protective box is fixedly connected to the front side wall of the top box, and a second motor is installed inside the protective box. A second rotating rod is fixedly connected to the output end of the second motor. A first gear ring is fixedly connected to the outer sides of both the front and rear ends of the second rotating rod. A second connecting rod is rotatably connected to the inner right side wall of the top box, and a second gear ring is fixedly connected to the outer sides of both the front and rear ends of the second connecting rod.
[0011] Furthermore, each of the top boxes is equipped with a rack ring inside. The inside of the two rack rings meshes with the outside of the two first gear rings and the second gear ring. A connecting ring is fixedly connected to the outside of each of the two rack rings, and a connecting block is fixedly connected to the inner sidewall of each of the two connecting rings.
[0012] Furthermore, a second support plate is fixedly connected to the other side of every two connecting blocks, and a scraper is fixedly connected to the bottom of each second support plate, with each scraper and the inclined plate being configured accordingly.
[0013] Compared with the prior art, the present invention has the following beneficial effects:
[0014] 1. This utility model, through its multi-layer stirring mechanism, solves the problem that adsorbents may settle at the bottom due to their weight, resulting in uneven distribution of substances in the upper and lower layers of wastewater and increased treatment costs. By having a first bevel gear mesh with two second bevel gears on the left and right sides of the device box, the rotational motion of the first bevel gear is transmitted and converted into the rotational motion of the four second bevel gears. A first connecting rod is fixedly connected inside each second bevel gear, with one end connected to the second bevel gear and the other end rotatably connected to the left side wall of the treatment box and the left side wall of the first support plate through bearings or other means. This effectively improves the coagulation and sedimentation effect and effectively removes suspended solids and some colloids from the wastewater.
[0015] 2. By incorporating a second rotating rod, a first gear ring, a second gear ring, a rack ring, connecting blocks, scrapers, and inclined plates, the system effectively addresses the issue of increased suspended solids and organic matter content in the effluent, which reduces the treatment efficiency of the flotation equipment and fails to guarantee that the effluent quality meets discharge standards. The rotation of the first and second gear rings, through gear meshing, drives the rack ring, which in turn rotates the second gear ring and the second connecting rod on the right side within the top chamber. Connecting rings fixed to the outer side of each rack ring move with its movement. Connecting blocks fixed to the inner wall of the connecting rings are connected to a second support plate; two connecting blocks fix one second support plate. As the connecting rings move, the second support plate also moves. The scraper fixed to the bottom of the second support plate moves, effectively improving the flotation separation efficiency, ensuring significant improvement in wastewater quality, extending equipment lifespan, reducing the frequency of equipment replacement and maintenance, and thus reducing operating costs.
[0016] The parts of the device not covered herein are the same as or can be implemented using existing technologies. Attached Figure Description
[0017] Figure 1 This is a three-dimensional structural diagram of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0018] Figure 2 This is a structural diagram of the rear side of the treatment tank of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0019] Figure 3 This is a cross-sectional view of the internal structure of the treatment tank of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0020] Figure 4 This is a structural diagram of the multi-layer stirring mechanism of the deep treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0021] Figure 5 This is a structural diagram of the device box for the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model;
[0022] Figure 6 This is a structural diagram of the second guide plate of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0023] Figure 7 This is a schematic diagram of the first gear ring of the deep treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0024] Figure 8 This is a structural diagram of the second rotating rod of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0025] Figure 9 This is a structural diagram of the scraper of the advanced treatment equipment for chemical industrial wastewater discharge proposed in this utility model.
[0026] Legend:
[0027] 1. Processing tank; 2. Multi-layer stirring mechanism; 201. First motor; 202. First rotating rod; 203. First fixing ring; 204. Stirring rod; 205. Device box; 206. First bevel gear; 207. Second bevel gear; 208. First connecting rod; 209. Second fixing ring; 210. Connecting plate; 211. Arc-shaped push plate; 3. Connecting pipe; 4. Air flotation hole; 5. Control panel; 6. First support plate; 7. First guide plate; 8. Second guide plate; 9. Sewage outlet pipe; 10. Top box; 11. Protection box; 12. Second motor; 13. Second rotating rod; 14. First gear ring; 15. Second connecting rod; 16. Second gear ring; 17. Rack ring; 18. Connecting ring; 19. Connecting block; 20. Second support plate; 21. Scraper; 22. Inclined plate. Detailed Implementation
[0028] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.
[0029] like Figure 1 - Figure 5As shown: Deep treatment equipment for chemical industrial wastewater discharge includes a treatment tank 1. The treatment tank 1 is equipped with a multi-layer stirring mechanism 2. A first support plate 6 is fixedly connected inside the treatment tank 1. The first support plate 6 divides the inside of the treatment tank 1 into two areas. The wastewater is treated on the left side, and impurities such as scum are collected on the right side.
[0030] The multi-layer stirring mechanism 2 includes: a first motor 201, two device boxes 205 and four second bevel gears 207. The front side wall of the first motor 201 is fixedly connected to the rear side wall of the processing box 1. The output end of the first motor 201 is fixedly connected to a first rotating rod 202. The front end of the first rotating rod 202 is rotatably connected to the inner front side wall of the processing box 1. By fixing the first motor 201 to the rear side wall of the processing box 1 and driving the first rotating rod 202 to rotate inside the processing box 1 through the output end of the first motor 201, the stability of the first rotating rod 202 during rotation is improved.
[0031] Each of the four first fixed rings 203 is fixedly connected to the outer side of the middle part of the first rotating rod 202. Each of the four first fixed rings 203 is fixedly connected to the outer side of the stirring rod 204. The first fixed rings 203 on the outer side of the first rotating rod 202 are connected to the stirring rod 204, and drive the stirring rod 204 to rotate, so as to stir the wastewater inside the treatment tank 1, so that the wastewater in the upper and lower layers inside the treatment tank 1 can be fully mixed with the reagents, etc. Both device boxes 205 are located on the outer sides of the front and rear ends of the first rotating rod 202. Four second bevel gears 207 are located on the left and right sides inside the two device boxes 205. The front and rear ends of the first rotating rod 202 are fixedly connected to the first bevel gears 206. The two first bevel gears 206 are located inside the device box 205. Each first bevel gear 206 meshes with the two second bevel gears 207. The device boxes 205 provide external protection for the second bevel gears 207 and the first bevel gears 206 inside the device box 205. The first bevel gears 206 on the front and rear ends of the first rotating rod 202 rotate inside the device box 205 to mesh with the two second bevel gears 207 inside the device box 205. When the first bevel gears 206 are not driven, they will drive the second bevel gears 207 to rotate.
[0032] Each second bevel gear 207 is internally fixedly connected to a first connecting rod 208. The other ends of the four first connecting rods 208 are rotatably connected to the left side wall inside the processing box 1 and the left side wall of the first support plate 6. After being driven by the second bevel gear 207, the other ends of the internal first connecting rods 208 will rotate on the left side wall inside the processing box 1 and the left side wall of the first support plate 6 to improve the stability during rotation and to support the device box 205, the second bevel gear 207 and the external device. Three second fixing rings 209 are fixedly connected to the outer side of each first connecting rod 208, and four connecting plates 210 are fixedly connected to the outer side of each second fixing ring 209. An arc-shaped push plate 211 is fixedly connected to the other side of each of the four connecting plates 210. The first connecting rod 208 is connected to the connecting plate 210 through the second fixing rings 209, and to the arc-shaped push plate 211 through the connecting plate 210. The first connecting rod 208 drives the arc-shaped push plate 211 to rotate. At the same time, the arc-shaped push plate 211 pushes the wastewater inside the treatment tank 1 that cannot come into contact with the reagent, so that the wastewater is pushed to the middle of the treatment tank 1, thereby improving the mixing effect of the substances in the wastewater.
[0033] like Figure 1 - Figure 6 As shown, a connecting pipe 3 runs through the left side wall of the treatment tank 1, connecting to external pipes to transfer wastewater into the treatment tank 1 for treatment. Air flotation holes 4 are provided on both the front and rear bottom sides of the treatment tank 1, connecting to external air flotation equipment to transfer gas into the treatment tank 1. The gas contacts the wastewater inside the treatment tank 1, generating bubbles that carry the mixed impurities to the surface of the wastewater.
[0034] A control panel 5 is fixedly connected to the front wall of the treatment tank 1. The entire device is controlled via the control panel 5. A first guide plate 7 is fixedly connected to the top of the first support plate 6. The first guide plate 7 guides the scum and other debris to flow to the right side of the treatment tank 1. A second guide plate 8 is fixedly connected to the right side of the interior of the treatment tank 1. A sludge discharge pipe 9 runs through the interior of the right side wall of the treatment tank 1. The second guide plate 8 guides the scum collected on the right side of the treatment tank 1 to flow through the sludge discharge pipe 9 and discharge it into the interior of the treatment tank 1. A top box 10 is connected to the top of the treatment tank 1. An inclined plate 22 is fixedly connected to the right side wall of the interior of the top box 10.
[0035] like Figure 1 - Figure 8As shown, a protective box 11 is fixedly connected to the front side wall of the top box 10. A second motor 12 is installed inside the protective box 11. The protective box 11 provides external protection for the second motor 12 and fixes it to the front side wall of the protective box 11. A second rotating rod 13 is fixedly connected to the output end of the second motor 12. First gear rings 14 are fixedly connected to the outer sides of both the front and rear ends of the second rotating rod 13. The rotation of the second rotating rod 13 inside the top box 10 drives the first gear rings 14 on the outer sides of both the front and rear ends of the second rotating rod 13 to rotate. A second connecting rod 15 is rotatably connected to the inner right side wall of the top box 10. Second gear rings 16 are fixedly connected to the outer sides of both the front and rear ends of the second connecting rod 15.
[0036] like Figure 1 - Figure 9 As shown, the top box 10 is equipped with rack rings 17 inside. The inside of the two rack rings 17 meshes with the outside of the two first gear rings 14 and the second gear ring 16. By setting the rack rings 17 on the outside of the first gear rings 14 and the second gear ring 16, the rack rings 17 are rotated by the first gear rings 14, and the second gear ring 16 is inside the right side of the rack rings 17, which in turn drives the second gear ring 16 to rotate and provides support for the rack rings 17 on both sides.
[0037] Two rack rings 17 are fixedly connected to the outer sides of each rack ring 17. Two connecting blocks 19 are fixedly connected to the inner side walls of each connecting ring 18. A second support plate 20 is fixedly connected to the other side of each pair of connecting blocks 19. A scraper 21 is fixedly connected to the bottom of each second support plate 20. Each scraper 21 is correspondingly set with an inclined plate 22. The connecting rings 18 on the rack ring 17 are connected to the connecting blocks 19, and the connecting blocks 19 fix the second support plate 20 to the inner wall of the two connecting rings 18, thereby driving the second support plate 20 to rotate up and down. The scraper 21 on the bottom of the second support plate 20 scrapes the impurities floating in the wastewater. When the scraper 21 rotates to the right side inside the top box 10, the scraper 21 contacts the inclined plate 22, and the inclined plate 22 scrapes the impurities sticking to the scraper 21, causing the impurities to fall into the interior of the first guide plate 7 and flow to the right side of the treatment box 1 for collection.
[0038] It should be noted that this utility model is a deep treatment device for chemical industrial wastewater discharge. First, the first motor 201, control panel 5, and second motor 12 are connected to an external power source to supply power to the device.
[0039] After the first motor 201 is started, its output end drives the first rotating rod 202 to rotate. The first motor 201 is fixed to the rear wall of the processing box 1, and its output shaft passes through the rear wall of the processing box 1 and is connected to the first rotating rod 202 inside the processing box 1. The front end of the first rotating rod 202 is mounted on the inner front side wall of the processing box 1 through a rotating connection such as bearings, so that it can rotate stably.
[0040] Four first fixing rings 203 are fixed on the outer side of the middle part of the first rotating rod 202. Each first fixing ring 203 is fixedly connected to a stirring rod 204, which will make a circular motion as the first rotating rod 202 rotates. During the rotation, these stirring rods 204 can stir the wastewater at different height levels in the treatment tank 1. The rotation of the stirring rods 204 breaks the static state of the wastewater, makes the wastewater form a water flow, promotes the mixing of various substances in the wastewater, and prevents the local concentration from being too high or too low.
[0041] Two device boxes 205 are provided on the outer sides of the front and rear ends of the first rotating rod 202. The first bevel gears 206, fixed at the front and rear ends of the first rotating rod 202, are located inside the device box 205. When the first rotating rod 202 rotates, the first bevel gears 206 rotate accordingly. Each first bevel gear 206 meshes with two second bevel gears 207 on the left and right sides inside the device box 205. In this way, the rotational motion of the first bevel gears 206 is transmitted and converted into the rotational motion of the four second bevel gears 207. A first connecting rod 208 is fixedly connected inside each second bevel gear 207. One end of the rod is connected to the second bevel gear 207, and the other end is rotatably connected to the left side wall inside the processing box 1 and the left side wall of the first support plate 6 through bearings or other means. The three second fixing rings 209 fixed on the outer side of the first connecting rod 208, the four connecting plates 210 fixedly connected on the outer side of each second fixing ring 209, and the finally connected arc-shaped push plate 211 together constitute the auxiliary stirring and propulsion structure.
[0042] When the first connecting rod 208 rotates, the arc-shaped pusher plate 211 rotates accordingly. These plates not only agitate the wastewater horizontally, creating complex flow patterns in the treatment tank 1, but also, due to their unique shape, propel the wastewater forward or backward. This propulsion helps the wastewater form a more complex three-dimensional flow pattern within the treatment tank 1, further enhancing the mixing effect of substances within the wastewater.
[0043] When the second motor 12 starts, its output drives the second rotating rod 13 to rotate. The first gear ring 14, fixed to the outer sides of the front and rear ends of the second rotating rod 13, rotates together with the second rotating rod 13. At the same time, the second connecting rod 15, rotatably connected to the inner wall of the right side inside the top box 10, and its second gear ring 16, fixed to the outer sides of the front and rear ends, also participate in the transmission process. The two rack rings 17 are inside the top box 10, and their interiors mesh with the outer sides of the first gear ring 14 and the second gear ring 16, respectively. When the first gear ring 14 and the second gear ring 16 rotate, the meshing action between the gears drives the rack rings 17 to move, which in turn drives the second gear ring 16 and the second connecting rod 15 to rotate inside the top box 10. The connecting ring 18, fixed to the outer side of each rack ring 17, moves with the movement of the rack ring 17. The connecting block 19, fixed to the inner wall of the connecting ring 18, is connected to the second support plate 20. Two connecting blocks 19 fix one second support plate 20. As the connecting ring 18 moves, the second support plate 20 also moves. The scraper 21, which is fixed at the bottom of the second support plate 20, moves on it.
[0044] When the scraper 21 is moved to the left side of 22, the sticky impurities on 21 can be scraped off by the inclined plate 22, so that these impurities fall into the interior of 7 and are guided to flow into the right side of 1 for collection.
[0045] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A deep treatment device for chemical industrial wastewater discharge, comprising a treatment tank (1), characterized in that: The processing box (1) is equipped with a multi-layer stirring mechanism (2), and a first support plate (6) is fixedly connected inside the processing box (1). The multi-layer stirring mechanism (2) includes: a first motor (201), two device boxes (205), and four second bevel gears (207). The front side wall of the first motor (201) is fixedly connected to the rear side wall of the processing box (1). The output end of the first motor (201) is fixedly connected to a first rotating rod (202). The front end of the first rotating rod (202) is rotatably connected to the inner front side wall of the processing box (1). A first fixing ring (203) is fixedly connected to the outer side of the middle part of the first rotating rod (202). A stirring rod (204) is fixedly connected to the outer side of each of the four first fixing rings (203). The two device boxes (205) are both located in the first... Four second bevel gears (207) are located on the outer sides of the front and rear ends of the rotating rod (202), and are located on the left and right sides inside the two device boxes (205). The front and rear ends of the first rotating rod (202) are fixedly connected to the first bevel gears (206). The two first bevel gears (206) are located inside the device box (205). Each first bevel gear (206) meshes with the two second bevel gears (207). Each second bevel gear (207) is fixedly connected to the inside of the first connecting rod (208). The other ends of the four first connecting rods (208) are rotatably connected to the left side wall inside the processing box (1) and the left side wall of the first support plate (6).
2. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 1, characterized in that: Three second fixing rings (209) are fixedly connected to the outer side of each first connecting rod (208), and four connecting plates (210) are fixedly connected to the outer side of each second fixing ring (209). An arc-shaped push plate (211) is fixedly connected to the other side of each of the four connecting plates (210).
3. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 1, characterized in that: A connecting pipe (3) is connected through the left side wall of the processing box (1). Air flotation holes (4) are opened on the bottom of the front and rear sides of the processing box (1). A control panel (5) is fixedly connected to the front side wall of the processing box (1). A first guide plate (7) is fixedly connected to the top of the first support plate (6).
4. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 1, characterized in that: The treatment box (1) is fixedly connected to the right side of the interior with a second guide plate (8), and the treatment box (1) is connected to the inside of the right side wall with a sewage pipe (9). The treatment box (1) is connected to the top of the treatment box (1), and the right side wall of the top box (10) is fixedly connected to an inclined plate (22).
5. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 4, characterized in that: A protective box (11) is fixedly connected to the front side wall of the top box (10). A second motor (12) is installed inside the protective box (11). A second rotating rod (13) is fixedly connected to the output end of the second motor (12). A first gear ring (14) is fixedly connected to the outer sides of both the front and rear ends of the second rotating rod (13). A second connecting rod (15) is rotatably connected to the inner right side wall of the top box (10). A second gear ring (16) is fixedly connected to the outer sides of both the front and rear ends of the second connecting rod (15).
6. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 5, characterized in that: The top box (10) is provided with rack rings (17) inside. The inside of the two rack rings (17) meshes with the outside of the two first gear rings (14) and the second gear ring (16). The outside of the two rack rings (17) is fixedly connected with connecting rings (18). The inner sidewalls of the two connecting rings (18) are fixedly connected with connecting blocks (19).
7. The advanced treatment equipment for chemical industrial wastewater discharge according to claim 6, characterized in that: A second support plate (20) is fixedly connected to the other side of each pair of connecting blocks (19), and a scraper (21) is fixedly connected to the bottom of each second support plate (20). Each scraper (21) is correspondingly set with an inclined plate (22).