Channel dredging mud treatment process and device based on water conservancy project

Abstract

The invention discloses a channel dredging slurry treatment process and device based on a water conservancy project, and relates to the technical field of channel dredging slurry treatment, the channel dredging slurry treatment device specifically comprises a drying cabin, and the drying cabin comprises a storage rack, a dehydration solid discharge mechanism and a rotary material distribution mechanism; energy circulation innovation is adopted, tail gas of a diesel engine is directly captured to serve as a drying heat source, external energy supply is replaced, energy consumption constraint of mobile equipment is broken, meanwhile, dehydration-drying integrated design is adopted, centrifugal dehydration and thin-layer heat drying are fused, the water content is reduced to 15% or below, the speed is increased by 50% compared with plate-and-frame pressure filtration, and the energy consumption is reduced. The rotary sleeve and the impact rod are linked with the scraper blade to clean the surface of the casing pipe in a self-adaptive mode, the problems of adhesion and blockage are solved, continuous treatment of high-viscosity slurry is ensured, an efficient, low-consumption and mobile solution is provided for dredged slurry treatment through double paths of process innovation and equipment integration, and the technical blank in the field of shipborne real-time treatment is filled up.

Description

Technical Field

[0001] The present invention relates to the technical field of waterway dredging slurry treatment, in particular to a waterway dredging slurry treatment process and device based on water conservancy projects. Background Art

[0002] The treatment of mud (usually a mixture of water, sediment, clay, organic matter and possible pollutants) generated by channel dredging is a key link in dredging projects, which is related to environmental compliance, resource utilization and cost control. The treatment process and equipment is a systematic project with the core goals of reduction, harmlessness, stabilization and resource utilization.

[0003] The technical difficulties in treating dredged sludge from waterways primarily lie in its high water content, complex composition, and the need to balance treatment efficiency with environmental protection requirements. For example, the patent application filed by the Shanghai Navigation Bureau of China Communications Construction Co., Ltd. (CN118908521A) utilizes a three-stage sludge tank connected in series with a plate-and-frame filter press, concentrating the sludge through flocculation and sedimentation. The residual water is then treated using a flotation unit and constructed wetlands. Although this process can reduce the load of plate and frame filter press, has good treatment effect and fast plate and frame filter press dehydration, it has high energy consumption and a long natural dehydration cycle, which makes it difficult to meet the continuous operation needs of channel dredging. In addition, it has large site requirements and needs to arrange multi-stage mud pools and conditioning pools. The equipment integration and mobility are limited, making it difficult to deploy large-scale fixed treatment facilities on dredging ships, resulting in the need for mud to be transported on shore, increasing costs and pollution risks. Summary of the Invention

[0004] The purpose of the present invention is to provide a waterway dredging mud treatment process and device based on water conservancy projects. It adopts energy recycling innovation, directly captures diesel engine exhaust as a drying heat source, replaces external power supply, and breaks the energy consumption constraints of mobile equipment. At the same time, the dehydration-drying integrated design combines centrifugal dehydration and thin-layer thermal drying to reduce the moisture content to below 15%, which is 50% faster than plate and frame filter pressing. It adopts a dual path of process innovation and equipment integration to provide an efficient, low-consumption, and mobile solution for dredging mud treatment, solving the problems raised in the background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a waterway dredging slurry treatment process based on a water conservancy project, comprising the following steps: Step 1: Preheating and recovery: The high-temperature exhaust gas emitted by the diesel-powered dredging vessel engine is captured through a high-temperature resistant pipe, and the cyclone dust collector removes sparks and large particles of impurities before discharging the gas into a heat pipe heat exchanger. Step 2: Using high-pressure steam as the heat transfer medium, the exhaust gas is first discharged into the heat pipe heat exchanger to transfer the heat energy to the purified wastewater, and the generated high-temperature steam is discharged into the drying chamber again; Step 3: The dredged mud is quickly concentrated to a solid content of 20-30% by a cyclone, and 0.1%-0.3% organic flocculant is added to improve the mud fluidity. At the same time, the screw pump transports the mud to the dewatering and solid removal mechanism; Step 4: The sludge is formed into a uniform thin layer of 3-5mm in the drying chamber through the rotating distribution mechanism. High-temperature steam circulates in the drying chamber casing to maintain the chamber temperature at 80-110℃. At the same time, the scraper at the bottom of the casing peels off and crushes the semi-dried sludge. The sludge falls step by step on the multi-layer casing. The total residence time is 10-30 minutes. Step 5: The purified exhaust gas is sprayed into the drying chamber at a flow rate of 5-8m / s to directly exchange heat with the sludge. The exhaust gas at the outlet of the drying chamber enters the condensation tower, is first cooled to 30℃ by the surface cooler, and then cooled to 5℃ by compression. The condensed water is recovered and recycled.

[0006] The present invention also provides a waterway dredging mud processing device based on a water conservancy project, which is applied to the waterway dredging mud processing process of the above-mentioned water conservancy project, including a drying chamber, the drying chamber including a storage rack, a dehydration and solid removal mechanism, and a rotary material distribution mechanism. The storage rack is installed on a diesel-powered dredging vessel, and the rotary material distribution mechanism is fixed to the top of the storage rack by bolts; A dehydration and solid removal mechanism is installed on the top of the rotating cloth mechanism, a filter box is installed on the storage rack on one side of the rotating cloth mechanism, a slide is slidably connected to the bottom of the storage rack, and a storage barrel is installed on the slide and at the bottom of the rotating cloth mechanism.

[0007] Furthermore, the dehydration and solid removal mechanism includes a centrifugal shell, an outer cover and an inner cover. The outer cover is movably connected to one side of the centrifugal shell, and the inner side of the outer cover is movably connected to the inner cover through a bearing. A sewage pipe is installed on the centrifugal shell, and one end of the sewage pipe passes through the inner cover and is movably connected to it. An exhaust port is opened at the top of the centrifugal shell, and the inner wall of the bottom of the centrifugal shell is connected to the filter box.

[0008] Furthermore, a coiling blade is fixed to the outer wall of the inner cover and located on the opposite side of the outer cover by welding. The inner cover rotates in opposite directions to the outer cover, and filtering holes are evenly opened on the outer cover.

[0009] Furthermore, the rotating cloth mechanism includes a heat conduction box, a sleeve and a movable scraper cover. The inner walls on both sides of the heat conduction box are evenly installed with sleeves, and the sleeves are two wear-resistant ceramic hollow tubes distributed side by side. The ends are sleeved with gears for meshing connection. The spacing between the sleeves arranged from top to bottom differs by 2-3 cm. A movable scraper cover is also symmetrically installed on the bottom of the sleeve.

[0010] Furthermore, a scraper is slidably connected in the top groove of the movable scraper cover, a slide rod is slidably connected to one side of the movable scraper cover, a return spring sleeve is installed on the inner wall of one side of the movable scraper cover, one end of the slide rod passes through the movable scraper cover and abuts against the return spring sleeve, and a connecting rod is rotatably connected between the slide rod and the scraper.

[0011] Furthermore, dust removal sleeves are fixed to both sides of the heat conduction box by bolts, and the dust removal sleeve on one side is connected and fixed with an exhaust pipe, and a stripping valve is installed at the bottom of the heat conduction box on the rotating cloth mechanism.

[0012] Furthermore, a rotary sleeve is movably connected to the inner wall of the dust removal sleeve on one side and located on the movable scraper cover side through a bearing, and a gear is installed on the rotary sleeve side to be meshed with a transmission gear shaft, and a gear is installed on one side of the transmission gear shaft to be meshed with the gear at the end of the adjacent side sleeve.

[0013] Furthermore, an impact rod is rotatably connected to the inner wall of the dust removal sleeve and is located on the opposite surface of the rotary sleeve and the movable scraper cover, and one side of the impact rod abuts against the rotary sleeve, and the other side abuts against the end of the sliding rod.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, energy recycling and sludge dewatering efficiency are significantly improved. By capturing the high-temperature exhaust gas of the diesel engine, the heat energy is converted into high-temperature steam through a heat pipe heat exchanger and directly used for sludge drying. At the same time, the purified exhaust gas is sprayed into the drying chamber at a high flow rate for secondary heat exchange, thereby realizing the cascade utilization of exhaust gas energy. The exhaust gas is finally recovered through a condensation tower for condensation and recycling, forming a "exhaust gas → steam → condensate" closed-loop system, which reduces energy consumption by more than 60% compared with traditional electric heating or natural drying. At the same time, sludge drying is removed, and the sludge is centrifuged at high speed in opposite directions through the inner and outer covers. The solid content is increased from the initial 20-30% to more than 50%, and the moisture filtration efficiency is increased by 40%. In addition, the multi-layer casing is thinned step by step, and dynamic heating with high-temperature steam is performed, so that the sludge moisture content is reduced from 70% to below 15%, and the drying efficiency is increased by more than 50%. In the present invention, a modular collaborative design and an anti-clogging and anti-coking mechanism are adopted. The inner cover coiling blades and the outer cover rotate in opposite directions to collaboratively scrape off the solid sludge to avoid clogging of the filter holes. The transmission gear shaft drives the sleeve to squeeze and adhere to the sludge, and the rotary sleeve is linked to the impact rod to trigger the scraper to scrape the material reciprocatingly, realizing the automation of the entire process of "centrifugal dehydration-thermal drying-scraping" without any additional energy consumption bottleneck. At the same time, the device is modularly integrated into the dredging ship storage rack, the slide storage barrel design supports rapid unloading, and the stripping valve empties the residual sludge with one click, reducing maintenance costs by 40%, making it convenient to complete effective sludge drying pretreatment when dredging mud in the waterway. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the process flow of dredging mud treatment for a waterway water conservancy project according to the present invention; Figure 2 This is a schematic diagram of the overall structure of a waterway dredging slurry processing device for a water conservancy project according to the present invention; Figure 3 Schematic diagram of the overall structure of the dehydration and solid removal mechanism of the present invention; Figure 4 This is a schematic diagram of the sleeve structure for installing the heat conduction box in the rotary material distribution mechanism of the present invention; Figure 5 This is a schematic diagram of the installation of the casing side rotating sleeve and the impact rod of the present invention; Figure 6 This is a schematic diagram of the transmission gear shaft of the present invention driving the upper and lower rotating sleeves to rotate; Figure 7 This is a schematic diagram of the connection structure between the scraper and the impact rod in the movable scraper cover of the present invention.

[0016] In the figure: 1, drying chamber; 10, storage rack; 11, dehydration and solid removal mechanism; 111, centrifugal shell; 112, sewage pipe; 113, exhaust port; 114, outer cover; 115, inner cover; 12. Rotating material distribution mechanism; 121. Heat conduction box; 122. Sleeve; 123. Movable scraper cover; 124. Transmission gear shaft; 125. Rotary sleeve; 126. Impact rod; 127. Slide rod; 128. Return spring sleeve; 129. Scraper; 2. Slide; 3. Storage barrel; 4. Filter box; 5. De-materialization valve; 6. Dust removal sleeve. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] See also Figure 1-7 , the present invention provides a technical solution: Example 1: The present invention realizes efficient dehydration and drying of mud on a diesel-powered dredging vessel through modular integration. The specific process is as follows: the dredged mud is first concentrated to a solid content of 20-30% by a cyclone, 0.2% organic flocculant is added to improve fluidity, and then the dredged mud is transported to the dehydration and solid removal mechanism 11 by a screw pump. Figure 3 As shown, the sludge is discharged into the inner cover 115 through the sewage pipe 112. The inner cover 115 and the outer cover 114 rotate in opposite directions, the inner cover 115 rotates counterclockwise and the outer cover 114 rotates clockwise. The sludge is thrown into the gap between the inner cover 115 and the outer cover 114 under the action of centrifugal force. The water is discharged through the filter holes on the outer cover 114 and flows into the filter box 4 through the bottom of the centrifugal shell 111 for storage. The purified sewage can be used for early heat exchange, while the dehydrated sludge is scraped off by the coiling blades welded on the outer wall of the inner cover 115 and discharged into the rotating distribution mechanism 12. At the same time, the high-temperature exhaust gas of the diesel engine is captured by a high-temperature resistant pipe, and after passing through a cyclone dust collector to remove sparks and large particles of impurities, it is introduced into a heat pipe heat exchanger. The heat energy is transferred through high-pressure steam, and the generated high-temperature steam is passed into the sleeve 122 in the rotating material distribution mechanism 12. Figure 2 and Figure 4 As shown, the sleeve 122 is installed in the guide box 121, with the dust removal sleeves 6 on both sides respectively corresponding to the sleeve 122. The high-temperature water vapor flows into the sleeve 122 through the dust removal sleeve 6 for heat exchange; The preliminarily dehydrated sludge is evenly distributed in the rotating distribution mechanism 12, as shown in FIG. Figure 4 As shown, the sludge enters through the inlet at the top of the heat conduction box 121, as shown in FIG. Figure 5 and Figure 6 As shown, the installed transmission gear shaft 124 drives the upper and lower sleeves 122 to rotate. When rotating clockwise, the upper and lower sleeves 122 squeeze the falling sludge inward at the same time, and the wet sludge adheres to the outer wall of the sleeve 122. In the absence of the scraper 129, part of the sludge falls directly, while the other part adheres to the surface of the sleeve 122 and is dried by the high-temperature sleeve 122 to form a thin layer of 3-5 mm. This prevents the sludge from being excessively dried and affecting the subsequent drying operation. For this purpose, a movable scraper cover 123 is installed on the bottom side of the corresponding sleeve 122; High temperature steam circulates in the hollow of the sleeve 122 to maintain the temperature of the cabin, and the sludge adheres to the surface of the sleeve 122 for heat exchange. During this process, the scraper 129 at the bottom of the movable scraper cover 123, such as Figure 7 As shown, the semi-dried sludge is peeled and crushed, and the sludge falls step by step on the multi-layer sleeve 122 under gravity, with a total residence time of 20 minutes, and finally falls into the storage barrel 3; As for the drive of the scraper 129, a rotary sleeve 125 is installed in the dust removal sleeve on one side, which is also driven by the transmission gear shaft 124. The gear on one side of the rotary sleeve 125 is engaged with the transmission gear shaft 124. The pipe surface on the other side is cut out with a notch, which is abutted by the sliding rod 127 in the one-sided movable scraper cover 123. The impact rod 126 installed between the rotary sleeve 125 and the sliding rod 127 squeezes the outer wall of the rotary sleeve 125 on one side. As the rotary sleeve 125 rotates, the pushed impact rod 126 contacts the sliding rod 127. like Figure 7As shown, when the slide bar 127 moves to the left, it also pushes the scraper 129 to move upward through the connecting rod, thereby contacting the sleeve 122 in the rotating process, scraping off the sludge adhering to its surface, and the falling sludge will be squeezed and dried for the second time, finally completing the multi-stage drying and dehydration operation, while improving the irregularity of the contact between the sludge and the sleeve 122. The entire movable scraper cover 123 will also deviate when the impact rod 126 contacts the slide bar 127, changing the position of the scraper 129 on the sleeve 122, forming a swinging scratch, improving the sludge crushing and mixing effect, and avoiding uneven sludge drying. Since the temperature of the initial high-temperature exhaust gas is relatively high after purification and heat transfer, it can be directly discharged into the drying chamber to increase the working temperature. The purified exhaust gas is sprayed into the drying chamber 1 at a flow rate of 6.5m / s for direct heat exchange. As the sludge water in the heat transfer box evaporates, steam is continuously discharged from the exhaust port. The outlet exhaust gas is discharged into the condensing tower through a pipeline, cooled to 30°C by the surface cooler, and then compressed and cooled to 5°C. The condensed water is also recycled and reused, that is, the exhaust gas waste heat recovery is deeply coupled with the sludge dehydration to realize energy circulation. The sludge moisture content is reduced from the initial 70% to below 15%, meeting the landfill or reuse standards. Compared with traditional natural drying, the efficiency is improved by more than 50%.

[0019] Example 2: With respect to the coordination mechanism between the dehydration and solid removal mechanism 11 and the rotary material distribution mechanism 12, the device operation is further refined: Figure 3 and Figure 4 As shown, in the dehydration and solid removal mechanism 11, the sewage pipe 112 passes through the inner cover 115 and is movably connected thereto. The inner cover 115 is driven by an independent motor to rotate counterclockwise at high speed, with a speed of 900 rpm, and the outer cover 114 rotates in the opposite direction at a low speed, with a speed of 250 rpm, through a bearing. After the sludge enters the inner cover 115, it impacts the inner wall of the outer cover 114 under centrifugal force, and the water is discharged to the filter box 4 through the filter holes, while the solid sludge is pushed to the bottom outlet by the winding blades of the inner cover 115 to avoid clogging. The discharged sludge falls into the top of the heat conduction box 121 of the rotating distribution mechanism 12; The core of the drying stage is the dynamic heating and scraping of the sleeve 122: Figure 5-7 As shown, the transmission gear shaft 124 is driven by a motor to drive the upper and lower rotary sleeves 125 to rotate synchronously. The rotary sleeve 125 is engaged with the gears at the end of the sleeve 122. When the rotary sleeve 125 rotates, the sludge is squeezed and attached to the surface of the sleeve 122. At the same time, high-temperature steam flows through the inner cavity of the rotary sleeve 125, continuously heating the sleeve 122 and quickly drying the sludge surface; The scraping mechanism of the movable scraper cover 123 is triggered by periodic impact: when the rotary sleeve 125 rotates, it pushes the impact rod 126, which abuts the sliding rod 127, overcomes the resistance of the return spring sleeve 128, and pushes the connecting rod, driving the scraper 129 to slide back and forth on the surface of the sleeve 122, peeling off and crushing the semi-dried sludge. The peeled sludge falls to the next layer of the sleeve 122 and repeats the drying process. The multi-layer design ensures uniform dehydration. If large clumps of sludge are encountered, the gear transmission system of the rotary sleeve 125; like Figure 6 As shown, the pressure is adjusted by differential speed to avoid overheating and coking, that is, the continuous operation of "centrifugal dehydration-thermal drying-scraping" is realized through mechanical linkage without additional energy consumption bottleneck. The dried sludge can be discharged through the stripping valve 5. For this purpose, a slide is installed on the storage rack 10 at the bottom of the entire drying chamber 1, and a storage barrel 3 is installed on the slide 2. After the stripping valve 5 is opened, the dried sludge falls into the storage barrel 3, which is convenient for subsequent personnel to transfer the sludge.

[0020] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A waterway dredging slurry treatment process based on a water conservancy project, characterized in that: The following steps are involved: Step 1: Preheating and recovery: The high-temperature exhaust gas emitted by the diesel-powered dredging vessel engine is captured through a high-temperature resistant pipe, and the cyclone dust collector removes sparks and large particles of impurities before discharging the gas into a heat pipe heat exchanger. Step 2: Using high-pressure steam as a heat transfer medium, the tail gas is first discharged into a heat pipe heat exchanger to transfer heat energy to the purified sewage, and the generated high-temperature steam is discharged into the drying chamber (1) again; Step 3: The dredged mud is quickly concentrated to a solid content of 20-30% by a hydrocyclone, and 0.1%-0.3% organic flocculant is added to improve the fluidity of the mud. At the same time, the screw pump transports the mud to the dewatering and solid removal mechanism (11); Step 4: The sludge is formed into a uniform thin layer of 3-5 mm in the drying chamber (1) through the rotating distribution mechanism (12). High-temperature steam circulates in the casing (122) of the drying chamber (1) to maintain the chamber temperature at 80-110°C. At the same time, the scraper (129) at the bottom of the casing (122) peels off and crushes the semi-dried sludge. The sludge falls step by step on the multi-layer casing (122). The total residence time is 10-30 minutes. Step 5: The purified tail gas is sprayed into the drying chamber (1) at a flow rate of 5-8m / s to directly exchange heat with the sludge. The tail gas at the outlet of the drying chamber (1) enters the condensation tower, is first cooled to 30°C by the surface cooler, and then cooled to 5°C by compression. The condensed water is recovered and recycled.

2. A waterway dredging mud treatment device based on a water conservancy project, applied to the waterway dredging mud treatment process of a water conservancy project as claimed in claim 1, characterized in that: The drying chamber (1) comprises a storage rack (10), a dehydration and solid removal mechanism (11) and a rotary material distribution mechanism (12). The storage rack (10) is installed on a diesel-powered dredging vessel, and the rotary material distribution mechanism (12) is fixed to the top of the storage rack (10) by bolts. A dehydration and solid removal mechanism (11) is installed on the top of the rotating material distribution mechanism (12), a filter box (4) is installed on the storage rack (10) on one side of the rotating material distribution mechanism (12), a slide (2) is slidably connected to the bottom of the storage rack (10), and a storage barrel (3) is installed on the slide (2) and at the bottom of the rotating material distribution mechanism (12).

3. The waterway dredging mud processing device based on water conservancy project according to claim 2 is characterized in that: The dehydration and solid removal mechanism (11) comprises a centrifugal shell (111), an outer cover (114) and an inner cover (115). One side of the centrifugal shell (111) is movably connected to the outer cover (114), and the inner side of the outer cover (114) is movably connected to the inner cover (115) via a bearing. A sewage guide pipe (112) is installed on the centrifugal shell (111), and one end of the sewage guide pipe (112) passes through the inner cover (115) and is movably connected thereto. An exhaust port (113) is provided at the top of the centrifugal shell (111), and the inner wall of the bottom of the centrifugal shell (111) is connected to the filter box (4).

4. The waterway dredging mud processing device based on water conservancy project according to claim 3 is characterized in that: The outer wall of the inner cover (115) is provided with a coiling blade fixed by welding on the surface opposite to the outer cover (114). The inner cover (115) and the outer cover (114) rotate in opposite directions. The outer cover (114) is provided with filter holes evenly spaced.

5. The waterway dredging mud processing device based on water conservancy project according to claim 4 is characterized in that: The rotary cloth mechanism (12) comprises a heat conduction box (121), a sleeve (122) and a movable scraper cover (123). The sleeves (122) are evenly installed on the inner walls of both sides of the heat conduction box (121). The sleeves (122) are two wear-resistant ceramic hollow tubes arranged side by side, and the ends are sleeved with gears for meshing connection. The spacing between the sleeves (122) arranged from top to bottom is 2-3 cm different. The movable scraper cover (123) is also symmetrically installed on the bottom of the sleeve (122).

6. The waterway dredging mud processing device based on water conservancy project according to claim 5 is characterized in that: A scraper (129) is slidably connected in the groove at the top of the movable scraper cover (123), a slide rod (127) is slidably connected to one side of the movable scraper cover (123), a return spring sleeve (128) is installed on the inner wall of one side of the movable scraper cover (123), one end of the slide rod (127) passes through the movable scraper cover (123) and abuts against the return spring sleeve (128), and a connecting rod is rotatably connected between the slide rod (127) and the scraper (129).

7. The waterway dredging slurry processing device based on water conservancy project according to claim 6 is characterized in that: Dust removal sleeves (6) are fixed to both sides of the heat conduction box (121) by bolts, and an exhaust pipe is connected and fixed to the dust removal sleeve (6) on one side. A stripping valve (5) is installed at the bottom of the heat conduction box (121) on the rotating material distribution mechanism (12).

8. The waterway dredging slurry processing device based on water conservancy project according to claim 7 is characterized in that: A rotary sleeve (125) is movably connected to the inner wall of the dust removal sleeve (6) on one side and located on the side of the movable scraper cover (123) through a bearing. A gear is installed on the side of the rotary sleeve (125) and is meshedly connected to a transmission gear shaft (124). A gear is installed on one side of the transmission gear shaft (124) and is meshedly connected to the gear at the end of the adjacent side sleeve (122).

9. The waterway dredging mud processing device based on water conservancy project according to claim 8, characterized in that: The inner wall of the dust removal sleeve (6) is rotatably connected to a collision rod (126) located on the opposite surface of the rotary sleeve (125) and the movable scraper cover (123), and one side of the collision rod (126) abuts against the rotary sleeve (125) and the other side abuts against the end of the sliding rod (127).

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