High-temperature acid gas venturi scrubbing tower for acidification kiln
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2026-08-14
AI Technical Summary
但现有的文丘里洗涤塔应用在酸化窑气体处理中时，由于喉管处调节装置的调节行程较短，使得调节堵头的调节范围有限，洗涤塔内的气体处理量较小，使得从酸化窑中排出的高温酸性气体堆积、堵塞在尾气管内，造成酸化窑负压得不到控制，尾气管与酸化窑之间通过鱼鳞片相接，但酸化窑内负压长时间得不到控制，会导致尾气管内的气体会从鱼鳞片、尾气管接口处泄漏，污染环境的同时，也会对鱼鳞片造成腐蚀
[0013]本实用新型的有益效果是：该酸化窑高温酸气文丘里洗涤塔通过采用直线传动机构驱动调节杆带动调节堵头控制喉管开口大小，以增大调节杆的调节行程，扩大调节堵头的调节范围，以及时处理从酸化窑排出的高温酸性含尘气体，避免从酸化窑中排出的高温酸性气体堆积、堵塞在尾气管内，以控制酸化窑内的负压，减少出口尾气罩处喷气现象，避免尾气管内气体从鱼鳞片、尾气管接口处泄漏，对鱼鳞片造成腐蚀。
Smart Images
Figure CN224628737U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of acidification kiln scrubbing tower technology, and in particular to a high-temperature acid gas venturi scrubbing tower for acidification kilns. Background Technology
[0002] An acidification kiln is an industrial piece of equipment used for the acid roasting of lithium concentrate, primarily for processing lithium ores such as spodumene and lithium aluminum phosphate. The acidification kiln uses high temperature and chemical reactions to react lithium ions in the lithium ore with sulfuric acid, generating soluble lithium salts, thereby achieving lithium extraction and purification. It typically employs a rotary kiln structure, using a rotating cylinder and heating system to subject the material to an acidification reaction at high temperatures. The acidic gases produced during the reaction form high-temperature acidic dust-laden gas in the high-temperature environment.
[0003] To treat and purify the high-temperature acidic dust-laden gas generated during the use of the acidification kiln, thereby reducing environmental pollution and protecting the equipment from corrosion, a scrubbing tower is connected to the tail gas pipe of the acidification kiln to treat the high-temperature acidic gas. The scrubbing tower neutralizes the acidic components (such as hydrogen chloride, sulfur dioxide, etc.) in the waste gas with the scrubbing liquid (such as alkaline solution or water) through gas-liquid contact, thereby purifying the waste gas.
[0004] Venturi scrubbers are commonly used to treat the high-temperature acidic gases discharged from acidification kilns to adapt to the high-temperature operating environment of the kilns. Specifically, the high-temperature acidic dust-laden gas discharged from the discharge end of the acidification kiln enters the Venturi scrubber through the inlet. It is first washed by a spray device, and then passes through a narrow throat. Due to the sharp increase in flow velocity, the dust particles in the gas are accelerated and carried to the wall of the scrubber. After the airflow enters the throat, the flow velocity gradually decreases, and the dust particles fall into the subsequent gas-liquid separation device under the action of gravity. However, when existing Venturi scrubbers are used in acidification kiln gas treatment, the adjustment stroke of the regulating device at the throat is relatively short, which limits the adjustment range of the regulating plug. This results in a small gas processing capacity in the scrubber, causing the high-temperature acidic gas discharged from the acidification kiln to accumulate and block the tail gas pipe. Consequently, the negative pressure in the acidification kiln cannot be controlled. The tail gas pipe is connected to the acidification kiln via fish scales, but if the negative pressure in the acidification kiln cannot be controlled for a long time, the gas in the tail gas pipe will leak from the fish scales and the tail gas pipe interface, polluting the environment and corroding the fish scales. Utility Model Content
[0005] The technical problem to be solved by this utility model is to provide a high-temperature acid gas venturi scrubbing tower for acidification kilns, which is mainly used for scrubbing high-temperature acid gas discharged from acidification kilns. The purpose is to increase the adjustment stroke of the regulating rod, expand the adjustment range of the regulating plug, facilitate the adjustment of the gas port at the throat, promptly handle high-temperature acidic dust-containing gas, ensure the scrubbing effect, and reduce the jetting phenomenon at the outlet tail gas hood.
[0006] This utility model discloses a throat regulating device for a high-temperature acid gas venturi scrubbing tower in an acidification kiln. It includes a tower body mounted on a frame, an air inlet connected to the tail gas pipe of the acidification kiln at the top, an air outlet connected to a gas-liquid separator at the bottom, a throat in the middle of the tower body, a spray device located above the throat and below the air inlet on the tower body, and a throat regulating device that extends and retracts vertically at the bottom of the tower body to control the size of the throat opening. The throat regulating device includes a cylindrical body vertically mounted on the frame and located below the tower body. One end of the cylindrical body penetrates the tower body and extends into the tower body. A mounting platform, sealed to the tower body, is provided around the circumference of the cylindrical body. Inside the cylindrical body is an adjusting rod that moves vertically along the length of the cylindrical body and a linear transmission mechanism that drives the adjusting rod. The fixed end of the linear transmission mechanism is connected to the cylindrical body, and the movable end of the linear transmission mechanism is fixedly connected to the adjusting rod. One end of the adjusting rod passes through the cylindrical body and has an adjusting plug for controlling the size of the throat opening.
[0007] Furthermore, the linear transmission mechanism includes a rotating rod and a sleeve that moves along the length of the rotating rod. The end of the sleeve away from the rotating rod is connected to an adjusting rod. One end of the rotating rod passes through the cylinder and is rotatably connected to the cylinder. The rotating rod is provided with a threaded section, and an adjusting nut is threadedly connected to the threaded section. The sleeve is provided with a limiting groove that matches the adjusting thread. The adjusting thread is rotatably disposed in the limiting groove to drive the sleeve to move along the length of the rotating rod.
[0008] As a preferred embodiment, a rotating handle is fixedly connected to the end of the rotating rod away from the sleeve.
[0009] In a preferred embodiment, the rotating handle includes a rotating block rotatably disposed within the cylinder and adapted to the cylinder. An extension rod penetrating the cylinder is fixedly connected to the rotating block. A crank handle is connected to one end of the extension rod located outside the cylinder. The rotating rod is detachably disposed on the rotating block and rotates synchronously with the rotating block.
[0010] Furthermore, the cylinder body has a first through hole for the adjusting rod to pass through, and a sealing gasket is provided on the inner side of the first through hole, with the adjusting rod circumferentially abutting against the sealing gasket.
[0011] Furthermore, the spraying device includes a first sprayer and a second sprayer. The first sprayer is located below the air inlet and is inclinedly arranged on the side wall of the tower body. The nozzle of the first sprayer penetrates the tower body and is inclined downward inside the tower body. The second sprayer includes a liquid inlet pipe that horizontally penetrates the tower body and extends into the tower body. A second spray head is connected to the liquid inlet pipe and is vertically downward.
[0012] As a preferred embodiment, at least two first sprayers are respectively installed on the side walls of opposite tower bodies, and at least two second spray heads are evenly distributed on the inlet pipe.
[0013] The beneficial effects of this utility model are as follows: The high-temperature acid gas venturi scrubbing tower of the acidification kiln uses a linear transmission mechanism to drive the adjusting rod to move the adjusting plug and control the size of the throat opening, thereby increasing the adjustment stroke of the adjusting rod and expanding the adjustment range of the adjusting plug, so as to timely treat the high-temperature acidic dust-containing gas discharged from the acidification kiln, avoid the accumulation and blockage of the high-temperature acidic gas discharged from the acidification kiln in the tail gas pipe, control the negative pressure in the acidification kiln, reduce the jet phenomenon at the outlet tail gas hood, and prevent the gas in the tail gas pipe from leaking from the fish scale and tail gas pipe interface, which would cause corrosion to the fish scale. Attached Figure Description
[0014] Figure 1 : A schematic diagram of the structure of the high-temperature acid gas venturi scrubbing tower for acidification kilns provided by this utility model;
[0015] Figure 2 : A schematic diagram of the throat adjustment device in use;
[0016] Figure 3 Schematic diagram of the throat adjustment device;
[0017] Reference numerals: 1-Frame; 2-Tower body; 21-Air inlet; 22-Air outlet; 23-Throat; 3-Throat adjusting device; 31-Cylinder; 311-Mounting platform; 312-First through hole; 313-Sealing gasket; 32-Adjusting rod; 33-Adjusting plug; 34-Linear transmission mechanism; 341-Rotating rod; 342-Threaded section; 343-Adjusting nut; 344-Sleeve; 345-Limiting groove; 35-Rotating handle; 351-Rotating block; 352-Extension rod; 353-Crank handle; 4-Spraying device; 41-First sprayer; 42-Second sprayer; 421-Liquid inlet pipe; 422-Second spray head. Detailed Implementation
[0018] The present invention will be further described below.
[0019] This utility model provides a high-temperature acid gas venturi scrubbing tower for acidification kilns, mainly used for scrubbing high-temperature acid gas discharged from acidification kilns. It includes a tower body 2 mounted on a frame 1. The tower body 2 has an inlet 21 connected to the tail gas pipe of the acidification kiln at its upper part, and an outlet 22 connected to a gas-liquid separator at its lower part. A throat 23 is located in the middle of the tower body 2. A spray device 4 is also provided on the tower body 2, located above the throat 23 and below the inlet 21. The bottom of the tower body 2 also has a throat adjusting device 3 that extends and retracts vertically to control the opening size of the throat 23. The throat adjusting device 3 includes a vertical... A cylindrical body 31 is mounted directly on the frame 1 and located below the tower body 2. One end of the cylindrical body 31 passes through the tower body 2 and extends into the tower body 2. The cylindrical body 31 is provided with a mounting platform 311 that is sealed and connected to the tower body 2 around its circumference. Inside the cylindrical body 31, there is an adjusting rod 32 that moves up and down along the length of the cylindrical body 31 and a linear transmission mechanism 34 that drives the adjusting rod 32. The fixed end of the linear transmission mechanism 34 is connected to the cylindrical body 31, and the movable end of the linear transmission mechanism 34 is fixedly connected to the adjusting rod 32. One end of the adjusting rod 32 passes through the cylindrical body 31 and is provided with an adjusting plug 33 for controlling the size of the opening of the throat 23.
[0020] like Figure 1 , Figure 2As shown, the tower body 2 of the high-temperature acid gas venturi scrubbing tower of the acidification kiln is mounted on the frame 1. The air inlet 21 at the top of the tower body 2 is connected to the tail gas pipe of the acidification kiln to receive the high-temperature acid gas containing dust discharged from the acidification kiln. The air outlet 22 at the bottom of the tower body 2 is connected to the gas-liquid separation device so that the treated gas can enter the gas-liquid separation device for further treatment. A throat 23 is provided in the middle of the tower body 2. A spray device 4 is also provided above the throat 23 and below the air inlet 21 to treat the gas and reduce dust. In order to facilitate the adjustment of the opening of the throat 23 to control the flow rate and negative pressure of the gas flowing through the throat 23, the bottom of the tower body 2 is also provided with upper and lower... A throat regulating device 3, which extends and retracts to control the size of the throat 23 opening, includes a cylindrical body 31 vertically mounted on the frame 1 and located below the tower body 2. One end of the cylindrical body 31 penetrates the tower body 2 and extends into it. To ensure the airtightness of the tower body 2 and prevent gas from escaping into the external environment and polluting it, the cylindrical body 31 is circumferentially provided with a mounting platform 311 that is sealed to the tower body 2. The sealing connection can be achieved by welding seals and welded joints or by applying a rubber ring tightly connected to the tower body 2 on the mounting platform 311. To improve the regulating capacity of the throat regulating device 3 and expand the regulating blockage... The adjustable range of head 33 allows for sufficient contact and mixing of the gas and liquid phases. When passing through the narrow cross-section of throat 23, the gas velocity is maximized, causing droplets to atomize under the high-speed airflow. Dust particles collide and coalesce violently with the droplets or between themselves, thus achieving particulate matter removal. The cylinder 31 is equipped with an adjusting rod 32 that moves vertically along its length, and a linear transmission mechanism 34 that drives the adjusting rod 32. The fixed end of the linear transmission mechanism 34 is connected to the cylinder 31, specifically through welding or bolting. The movable end of the linear transmission mechanism 34 is fixedly connected to the adjusting rod 32 to drive the adjusting rod 32 along the cylinder. The length direction of 31 moves, thereby driving the adjusting plug 33 set on the adjusting rod 32 to control the opening size of the throat 23; the above-mentioned linear transmission mechanism 34 can adopt an existing electric push rod or gear rack telescopic mechanism to increase the adjusting stroke of the adjusting rod 32 and expand the adjusting range of the adjusting plug 33, so as to deal with the high temperature acidic dust gas discharged from the acidification kiln in a timely manner, and avoid the high temperature acidic gas discharged from the acidification kiln from accumulating and blocking in the tail gas pipe, causing the negative pressure of the acidification kiln to be out of control, resulting in jetting at the outlet tail gas hood, causing the gas in the tail gas pipe to leak from the fish scale and tail gas pipe interface, causing corrosion to the fish scale.
[0021] As a preferred approach, to enable the linear transmission mechanism 34 to be suitable for high-temperature and acidic environments and to save costs, such as Figure 3As shown, the linear transmission mechanism 34 includes a rotating rod 341 and a sleeve 344 that moves along the length of the rotating rod 341. One end of the sleeve 344 away from the rotating rod 341 is connected to an adjusting rod 32. One end of the rotating rod 341 passes through the cylinder 31 and is rotatably connected to it. The rotating rod 341 has a threaded section 342, and an adjusting nut 343 is threaded onto the threaded section 342. The sleeve 344 has a limiting groove 345 adapted to the adjusting thread. The adjusting nut 343 is positioned within the limiting groove 345 to drive the sleeve 344 to rotate along the threaded section 341. The rod 341 moves along its length. The rotating rod 341 serves as the fixed end of the linear transmission mechanism 34, and the sleeve 344 serves as the movable end of the linear transmission mechanism 34. The rotating rod 341 is rotatably connected to the cylinder 31. The rotating rod 341 also has a threaded section 342, on which an adjusting nut 343 is threadedly connected. By rotating the rotating rod 341, the adjusting nut 343 on the threaded section 342 rotates along the threaded section 342, that is, moves up and down along the length of the rotating rod 341. The adjusting nut 343 is positioned within the limiting groove 345 of the sleeve 344. The sleeve 344 and adjusting nut 343 move up and down synchronously along the length of the rotating rod 341; the sleeve 344 drives the adjusting rod 32 connected to it to move up and down along the length of the sleeve 344, so that the rotating rod 341 with threaded section 342 drives the sleeve 344 and the adjusting rod 32 installed on the sleeve 344 to move up and down, so as to control the adjusting plug 33 set on the adjusting rod 32 to block the opening of the throat pipe 23, thereby controlling the flow rate of gas in the scrubbing tower through the throat pipe 23, ensuring the scrubbing effect and treatment capacity of the gas in the scrubbing tower; and the thread is set on the threaded section The travel distance of the adjusting nut 343 on 342 is controllable. The linear transmission mechanism 34 with this configuration can be directly assembled using parts available on the construction site, saving costs. At the same time, the travel distance of the adjusting nut 343 can be controlled according to the configuration of the threaded section 342. The rotating rod 341 adapted to the threaded section 342 can be selected according to different gas throughput to ensure that the high-temperature acidic gas discharged from the acidification kiln can be treated in a timely manner in the scrubbing tower, avoiding the accumulation and blockage of the high-temperature acidic gas discharged from the acidification kiln in the tail gas pipe, while ensuring the gas treatment effect and avoiding environmental pollution.
[0022] To facilitate the operator's rotation of the rotating rod 341 to adjust the distance between the adjusting plug 33 and the throat 23, thereby adjusting the size of the opening of the throat 23, such as... Figure 3 As shown, a rotating handle 35 is fixedly connected to the end of the rotating rod 341 away from the sleeve 344; specifically, the rotating handle 35 is fixedly connected to the rotating rod 341, which can be welded or integrally formed. As a preferred embodiment, to ensure that the rotating rod 341 does not shift due to excessive length when rotating, thus affecting the sliding stability of the sleeve 344 and the adjusting rod 32, such as... Figure 3 As shown, the rotating handle 35 includes a rotating block 351 rotatably disposed inside and adapted to the cylinder 31. An extension rod 352 penetrating the cylinder 31 is fixedly connected to the rotating block 351. A crank handle 353 is connected to one end of the extension rod 352 located outside the cylinder 31. The rotating rod 341 is detachably disposed on the rotating block 351 and rotates synchronously with the rotating block 351. The rotating block 351, rotatably disposed inside the cylinder 31, drives the rotating rod 341 to rotate, thereby limiting the left and right movement of the rotating rod 341. Furthermore, the rotating block 351 is adapted to the cylinder 31 and will not move left or right during rotation. The offset is to ensure that the rotating rod 341 remains vertical during rotation. An extension rod 352 that penetrates the cylinder 31 is fixed to the rotating block 351. The operator drives the rotating block 351 to rotate by means of a crank 353 connected to the end of the extension rod 352 located outside the cylinder 31, thereby driving the rotating rod 341 to rotate. This causes the adjusting nut 343 located on the rotating rod 341 to move along the threaded section 342 of the rotating rod 341, thereby causing the sleeve 344 to move up and down along the length of the rotating rod 341, thereby adjusting the position of the adjusting rod 32 connected to the sleeve 344 and the adjusting plug 33.
[0023] To prevent spray liquid or gas from entering the cylinder 31 through the gap between the adjusting rod 32 and the first through hole 312, and causing corrosion to the adjusting nut 343, the rotating rod 341, or the connection between the two; Figure 3 As shown, the cylinder 31 has a first through hole 312 for the adjusting rod 32 to pass through. A sealing gasket 313 is provided on the inner side of the first through hole 312, and the circumferential direction of the adjusting rod 32 abuts against the sealing gasket 313. By providing a sealing gasket 313 on the inner side of the first through hole 312, the circumferential direction of the adjusting rod 32 abuts against the sealing gasket 313. The sealing gasket 313 can be made of elastic rubber or other materials that do not react with acidic or alkaline substances, so that the adjusting rod 32 can move up and down along the length of the cylinder 31, and the sealing connection between the adjusting rod 32 and the cylinder 31 can be guaranteed.
[0024] To further ensure the washing effect of spray device 4 on the high-temperature acidic dust-laden gas generated by the acidification kiln, such as Figure 1 , Figure 2As shown, the spraying device 4 includes a first sprayer 41 and a second sprayer 42. The first sprayer 41 is located below the air inlet 21 and is inclinedly arranged on the side wall of the tower body 2. The nozzle of the first sprayer 41 penetrates the tower body 2 and is inclined downward inside the tower body 2. The second sprayer 42 includes a liquid inlet pipe 421 that horizontally penetrates the tower body 2 and extends into the tower body 2. A second sprayer 422 is connected to the liquid inlet pipe 421 and is vertically downward. By setting the first sprayer 41 below the air inlet 21, the high-temperature acidic dust-laden gas entering the high-temperature acid gas Venturi scrubbing tower of the acidification kiln is subjected to the first spray scrubbing. The second sprayer 422 is set above the throat pipe 23. The first sprayer 42 performs a second spray wash on the high-temperature, acidic, dust-laden gas about to pass through the throat 23, ensuring a thorough cleaning effect through two washes. The first sprayer 41 is inclined and positioned on the side wall of the tower body 2, with its nozzle penetrating the tower body 2 and angled downwards. This allows the liquid sprayed by the first sprayer 41 to cover a wide area, performing a first spray wash on the gas inside the tower without affecting the gas escape area. The inlet pipe 421 of the second sprayer 42 extends horizontally into the tower body 2, and a vertically downward-facing second spray head 422 is connected to the inlet pipe 421. This ensures that the liquid sprayed by the second sprayer 42 precisely and vertically downwards targets the gas about to enter the throat 23 for a second spray wash, guaranteeing a thorough cleaning effect. To ensure the cleaning effect, such as... Figure 1 , Figure 2 As shown, at least two first sprayers 41 are respectively arranged on the side walls of opposite tower bodies 2, and at least two second spray heads 422 are evenly distributed on the inlet pipe 421. The first sprayers 41 can be arranged on each side wall of the tower body 2 to perform the first spray washing of the high-temperature acidic dust-laden gas entering the scrubbing tower from the air inlet 21. The spray range of the first sprayers 41, which are inclined to each side wall of the tower body 2, can cover the area where the gas escapes into the tower body 2. Then, by increasing the number of second spray heads 422, a second spray washing is performed on the high-temperature acidic dust-laden gas entering the throat pipe 23 to ensure the washing effect.
Claims
1. A high-temperature acid gas venturi scrubbing tower for an acidification kiln, comprising a tower body (2) mounted on a frame (1), wherein an air inlet (21) connected to the tail gas pipe of the acidification kiln is provided above the tower body (2), an air outlet (22) connected to a gas-liquid separator is provided below the tower body (2), a throat (23) is provided in the middle of the tower body (2), a spray device (4) is also provided on the tower body (2) above the throat (23) and below the air inlet (21), and a throat adjusting device (3) is provided at the bottom of the tower body (2) for vertically extending and retracting to control the size of the opening of the throat (23), characterized in that: The throat adjustment device (3) includes a cylinder (31) vertically mounted on the frame (1) and located below the tower body (2). One end of the cylinder (31) passes through the tower body (2) and extends into the tower body (2). The cylinder (31) is provided with a mounting platform (311) that is sealed to the tower body (2) in the circumferential direction. The cylinder (31) is provided with an adjustment rod (32) that moves up and down along the length of the cylinder (31) and a linear transmission mechanism (24) that drives the adjustment rod (32) to move. The fixed end of the linear transmission mechanism (24) is connected to the cylinder (31), and the movable end of the linear transmission mechanism (24) is fixedly connected to the adjustment rod (32). One end of the adjustment rod (32) passes through the cylinder (31) and is provided with an adjustment plug (33) for controlling the size of the throat (23) opening.
2. A high temperature acid gas venturi scrubber tower for an acid kiln as recited in claim 1, characterized by: The linear transmission mechanism (24) includes a rotating rod (341) and a sleeve (344) that moves along the length of the rotating rod (341). One end of the sleeve (344) away from the rotating rod (341) is connected to an adjusting rod (32). One end of the rotating rod (341) passes through the cylinder (31) and is rotatably connected to the cylinder (31). The rotating rod (341) is provided with a threaded section (342), and an adjusting nut (343) is threadedly connected to the threaded section (342). The sleeve (344) is provided with a limiting groove (345) that is adapted to the adjusting thread. The adjusting nut (343) is rotatably set in the limiting groove (345) to drive the sleeve (344) to move along the length of the rotating rod (341).
3. A high temperature acid gas venturi scrubber tower for an acid kiln as recited in claim 2, characterized by: A rotating handle (35) is fixedly connected to the end of the rotating rod (341) away from the sleeve (344).
4. A high temperature acid gas venturi scrubber tower for an acid kiln as recited in claim 3, characterized by: The rotating handle (35) includes a rotating block (351) rotatably disposed inside the cylinder (31) and adapted to the cylinder (31). An extension rod (352) that penetrates the cylinder (31) is fixedly connected to the rotating block (351). One end of the extension rod (352) located outside the cylinder (31) is connected to a rocker arm (353). The rotating rod (341) is detachably disposed on the rotating block (351) and rotates synchronously with the rotating block (351).
5. A high temperature acid gas venturi scrubber tower for an acid kiln as recited in claim 1, c h a r a c t e r i z e d i n that: The cylinder (31) has a first through hole (312) for the adjusting rod (32) to pass through. A sealing gasket (313) is provided on the inner side of the first through hole (312), and the adjusting rod (32) abuts against the sealing gasket (313) in the circumferential direction.
6. A high temperature acid gas venturi scrubber tower for an acid kiln as recited in claim 1, c h a r a c t e r i z e d i n that: The spraying device (4) includes a first sprayer (41) and a second sprayer (42). The first sprayer (41) is located below the air inlet (21). The first sprayer (41) is inclinedly located on the side wall of the tower body (2). The nozzle of the first sprayer (41) penetrates the tower body (2) and is inclined downward inside the tower body (2). The second sprayer (42) includes a liquid inlet pipe (421) that runs horizontally through the tower body (2) and extends into the tower body (2). A second spray head (422) is connected to the liquid inlet pipe (421), and the second spray head (422) is set vertically downward.
7. An acid gas venturi scrubber tower for use in a high temperature acid kiln as defined in claim 6 wherein: At least two first sprayers (41) are respectively installed on the side walls of opposite tower bodies (2), and at least two second spray heads (422) are evenly distributed on the inlet pipe (421).