A kind of waste transfer station leachate treatment equipment

Abstract

The present application relates to the technical field of landfill leachate treatment, in particular to a landfill transfer station leachate treatment equipment, which comprises a heat exchange body, a heat exchange cavity and a plurality of material channels located in the heat exchange cavity are arranged in the heat exchange body; the heat exchange cavity is connected with an air inlet and an air outlet; the heat exchange body is provided with a feeding port and a discharging port which are in communication with the plurality of material channels at both ends; the heat exchange body is provided with a detection assembly for detecting the viscosity of the material at the position corresponding to the feeding port; the air inlet is connected with an air inlet control assembly; the air inlet control assembly is connected with the detection assembly through a connecting pipe to control the steam flow into the heat exchange cavity according to the viscosity of the material; the real-time closed-loop linkage regulation and control of the viscosity change of the leachate material and the steam supply amount of the heat exchange cavity is realized, without the need for an electric control system and manual intervention, which can automatically increase the steam flow and heat exchange load when the viscosity of the material increases, and can automatically reduce the steam flow when the viscosity of the material decreases.

Description

Technical Field

[0001] This invention relates to the field of landfill leachate treatment technology, and in particular to a landfill leachate treatment device. Background Technology

[0002] Waste transfer stations generate large amounts of leachate during waste compression and temporary storage. This leachate typically has a high organic content, complex composition, and fluctuating concentration. Therefore, mechanical vapor recompression (MVR) evaporation processes are often used for volume reduction. In this type of equipment, the shell-and-tube heat exchanger serves as the core heat exchange component. The leachate material flows in the tubes while steam exchanges heat on the shell side, causing the leachate to continuously evaporate and concentrate.

[0003] However, during the evaporation process, as water gradually evaporates, the material concentration and viscosity increase, and the flow resistance increases. If the steam flow rate cannot be adjusted in time, it can easily lead to a decrease in heat exchange efficiency, local overheating or dry burning, while increasing energy waste and equipment wear, and affecting the stable operation of the system.

[0004] Therefore, existing equipment usually relies on electronic control or manual adjustment of steam valves to change the steam flow rate. However, under the complex and high-viscosity conditions of landfill leachate, this method is structurally complex, has a slow response, and is easily affected by corrosion or blockage, making it difficult to meet the requirements of efficient and stable evaporation treatment. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a leachate treatment device for waste transfer stations, which effectively improves the stability, reliability and continuous operation cycle of the equipment.

[0006] To achieve the above objectives, the specific solution of the present invention is as follows: A leachate treatment device for a waste transfer station includes a heat exchange body, wherein the heat exchange body is provided with a heat exchange chamber and multiple material channels located within the heat exchange chamber; the heat exchange chamber is connected to an air inlet and an exhaust outlet; and both ends of the heat exchange body are provided with a feed inlet and a discharge outlet communicating with the multiple material channels. The heat exchanger body is equipped with a detection component for detecting the viscosity of the material at the corresponding feed inlet position; the air inlet is connected to an air intake control component; the air intake control component is connected to the detection component through a connecting pipe to control the steam flow rate entering the heat exchange chamber according to the material viscosity.

[0007] Furthermore, the intake control assembly includes an intake valve body with an intake channel; the intake valve body is provided with a connecting arm, the connecting arm has an installation cavity, a control piston is movably disposed in the installation cavity, the control piston divides the installation cavity into a rod-side cavity and a rodless cavity, wherein the rodless cavity is in communication with the outside atmosphere; a connecting pipe is connected to the end of the connecting arm, the connecting pipe has a connecting channel; the piston rod of the control piston is movably embedded in the connecting channel and can reciprocate along the axial direction of the connecting channel; An elastic piston ball is embedded in the air intake channel; the interior of the elastic piston ball is connected to the rod chamber; both the elastic piston ball and the rod chamber are filled with a transmission medium.

[0008] Furthermore, the detection assembly includes a sealing valve plate and an elastic element; the end of the connecting pipe away from the intake control assembly is provided with a receiving cavity; the sealing valve plate is movably and sealingly disposed in the receiving cavity, thereby forming a detection cavity communicating with the connecting channel; the two ends of the elastic element abut against the inner walls of the sealing valve plate and the receiving cavity, respectively.

[0009] Furthermore, the elastic element is a spring.

[0010] Furthermore, the control piston mates with the inner wall surface of the mounting cavity to restrict the rotational freedom of the control piston.

[0011] Furthermore, the heat exchange body includes a heat exchange shell, a lower end cover, and an upper end cover; the upper end cover and the lower end cover are respectively fixed to the upper and lower ends of the heat exchange shell; an upper partition is provided between the upper end cover and the upper end of the heat exchange shell; a lower partition is provided between the lower end cover and the lower end of the heat exchange shell; a discharge chamber communicating with the discharge port is formed between the upper end cover, the upper partition, and the heat exchange shell; a feed chamber communicating with the feed inlet is formed between the lower end cover, the lower partition, and the heat exchange shell; and the heat exchange chamber is formed between the upper partition, the lower partition, and the heat exchange shell. Multiple heat exchange tubes are connected between the upper and lower partitions; the upper and lower ends of each heat exchange tube are respectively connected to the discharge chamber and the feed chamber; the material channel is formed inside the heat exchange tube.

[0012] Furthermore, the lower end cover is provided with a connector that communicates with the feed chamber; one end of the connecting pipe near the lower end cover is sealed and inserted into the connector.

[0013] Furthermore, the elastic piston ball is provided with a connecting part; a flexible hose is provided between the connecting part and the control piston; one end of the flexible hose is sealed and inserted into the connecting part and communicates with the interior of the elastic piston ball; the other end of the flexible hose is sealed and passes through the control piston and communicates with the rod chamber.

[0014] The beneficial effects of this invention are as follows: This invention sets up a detection component linked to the air intake control component at the feed inlet of the heat exchanger body, realizing a purely mechanical real-time closed-loop linkage control between changes in leachate viscosity and the steam supply to the heat exchange chamber. This eliminates the need for an electrical control system and manual intervention. It can automatically increase the steam flow and heat exchange load when the material viscosity increases, offsetting the decrease in heat exchange efficiency caused by the increase in liquid-side thermal resistance, effectively avoiding problems such as localized overheating, dry burning, coking, and scaling of the heat exchange tubes. Conversely, it can automatically reduce the steam flow when the material viscosity decreases, effectively preventing ineffective energy consumption caused by excessive steam supply. Simultaneously, it effectively avoids the defects of electrical components being prone to corrosion, clogging, and failure under harsh leachate treatment conditions, effectively improving the stability, reliability, and continuous operation cycle of the equipment, reducing the maintenance cost and energy consumption throughout the equipment's life cycle, and ensuring stable compliance with leachate evaporation and volume reduction treatment effects under different concentrations and viscosities. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural schematic diagram of the leachate treatment equipment for a waste transfer station according to the present invention; Figure 2 This is a cross-sectional schematic diagram of the leachate treatment equipment for the waste transfer station of the present invention; Figure 3 yes Figure 2 A magnified view of a portion of point M in the middle; Figure 4 yes Figure 2 A magnified view of a portion of point N in the diagram; Explanation of reference numerals in the attached drawings: 1. Heat exchanger body; 11. Heat exchanger shell; 121. Lower end cover; 1211. Connector; 122. Upper end cover; 13. Heat exchange chamber; 141. Air inlet; 142. Exhaust outlet; 151. Feed inlet; 152. Discharge outlet; 161. Upper partition; 162. Lower partition; 171. Discharge chamber; 172. Feed chamber; 18. Heat exchanger tube; 21. Sealing valve plate; 22. Elastic element; 3. Air inlet control assembly; 31. Air inlet valve body; 311. Connecting arm; 312. Air inlet channel; 313. Mounting cavity; 32. Control piston; 33. Elastic piston ball; 331. Connecting part; 34. Hose; 4. Connecting pipe; 41. Connecting channel; 5. Detection chamber. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this is not to limit the scope of the invention to this.

[0017] like Figures 1 to 4As shown in the figure, the leachate treatment equipment for a waste transfer station described in this embodiment includes a heat exchange body 1, a heat exchange chamber 13 and multiple material channels located within the heat exchange chamber 13; the heat exchange chamber 13 is connected to an air inlet 141 and an exhaust outlet 142; both ends of the heat exchange body 1 are provided with an inlet 151 and an outlet 152 communicating with the multiple material channels; the heat exchange body 1 is provided with a detection component for detecting the viscosity of the material at the position corresponding to the inlet 151; the air inlet 141 is connected to an air intake control component 3; the air intake control component 3 is connected to the detection component through a connecting pipe 4 to control the steam flow rate entering the heat exchange chamber 13 according to the material viscosity.

[0018] Specifically, such as Figure 1 and Figure 2 As shown, the heat exchanger body 1 includes a heat exchange shell 11, a lower end cover 121, and an upper end cover 122. The heat exchange shell 11 is a cylindrical structure with open ends. Both the upper end cover 122 and the lower end cover 121 are cylindrical cap-shaped structures adapted to the heat exchange shell 11. Flanges are fixedly installed at both ends of the heat exchange shell 11, at the open ends of the upper end cover 122 and the lower end cover 121. The upper end cover 122 and the lower end cover 121 are respectively sealed and fixedly installed at the upper and lower ends of the heat exchange shell 11 by the flanges and sealing fasteners. An upper partition 161 is sealed between the upper end cover 122 and the upper end of the heat exchange shell 11, and the lower end cover 121 is sealed between the lower end of the heat exchange shell 11 and the lower end of the heat exchange shell 11. A lower partition 162 is sealed between the ends. Both the upper partition 161 and the lower partition 162 are circular plate structures, and their outer edges are sealed to the inner wall of the heat exchange shell 11. A discharge chamber 171 communicating with the discharge port 152 is formed between the inner wall of the upper end cover 122, the upper surface of the upper partition 161, and the upper inner wall of the heat exchange shell 11. A feed chamber 172 communicating with the feed port 151 is formed between the inner wall of the lower end cover 121, the lower surface of the lower partition 162, and the lower inner wall of the heat exchange shell 11. A heat exchange chamber 13 is formed between the lower surface of the upper partition 161, the upper surface of the lower partition 162, and the middle inner wall of the heat exchange shell 11. Multiple heat exchange tubes 18 are sealed and connected between the upper partition 161 and the lower partition 162; the multiple heat exchange tubes 18 are evenly arranged in a circular array with the central axis of the heat exchange shell 11 as the center; the upper and lower ends of each heat exchange tube 18 pass through the upper partition 161 and the lower partition 162 respectively, and are connected to the discharge chamber 171 and the feed chamber 172 respectively; the hollow channel inside the heat exchange tube 18 forms a material channel.

[0019] In actual use, the leachate from the waste transfer station to be treated is continuously fed into the feed chamber 172 through the feed inlet 151. After being evenly distributed in the feed chamber 172, it enters the material channels of each heat exchange tube 18, and flows through the heat exchange chamber 13 area along the material channels. At the same time, the detection component detects the viscosity of the leachate entering the feed chamber 172 in real time. The air intake control component 3 is linked with the detection component through the connecting pipe 4, and controls the air intake into the heat exchange chamber 13 through the air inlet 141 in real time according to the detected leachate viscosity. The heating steam flow rate; after the heating steam enters the heat exchange chamber 13, it exchanges heat with the permeate flowing in the heat exchange tube 18 through the tube wall of the heat exchange tube 18. After the permeate absorbs heat, the water evaporates to achieve concentration and volume reduction. After the steam in the heat exchange chamber 13 releases heat, it forms condensate. The uncondensed steam after heat exchange and the condensate are discharged from the heat exchange chamber 13 through the exhaust port 142. The permeate after heat absorption, evaporation and concentration enters the discharge chamber 171 and is finally discharged from the heat exchange body 1 through the discharge port 152, completing the evaporation treatment of the permeate.

[0020] When the viscosity of the leachate to be treated increases, the flow resistance and flow rate of the leachate in the material channel increase, thereby causing the static pressure in the feed chamber 172 to increase synchronously. The detection component responds synchronously to the pressure change in the feed chamber 172, transmitting the viscosity change signal to the air intake control component 3 through the connecting pipe 4. The air intake control component 3 then increases the steam flow rate into the heat exchange chamber 13 accordingly, thereby increasing the saturation temperature and heat exchange load of the steam on the heating side. This counteracts the problem of increased liquid-side thermal resistance caused by the increase in material viscosity, ensuring heat exchange efficiency and evaporation effect. Similarly, when the viscosity of the leachate to be treated increases... When the viscosity of leachate decreases, the flow resistance and flow rate of leachate in the material channel decrease, and the static pressure in the feed chamber 172 decreases synchronously. The detection component resets synchronously according to the pressure change in the feed chamber 172, and drives the air intake control component 3 to reduce the steam flow rate entering the heat exchange chamber 13 through the connecting pipe 4, so as to avoid energy waste caused by excessive steam, and at the same time reduce unnecessary heat load and wear of the equipment. In this way, a purely mechanical automatic steam flow regulation based on the change of material viscosity is achieved without the need for an electrical control system and manual intervention, which is suitable for treatment scenarios with large fluctuations in leachate concentration and complex operating conditions.

[0021] In some embodiments of the leachate treatment equipment for the waste transfer station in this example, such as Figure 2 and Figure 4As shown, the intake control assembly 3 includes an intake valve body 31 with an axially penetrating intake channel 312. The two ends of the intake channel 312 are respectively sealed and connected to an external steam supply pipeline and an intake port 141 of the heat exchange body 1. The outer wall of the intake valve body 31 is integrally formed with a connecting arm 311. The connecting arm 311 extends in a direction perpendicular to the axis of the intake channel 312. The connecting arm 311 has an installation cavity 313. A control piston 32 is sealed and movably installed in the installation cavity 313. The control piston 32 divides the installation cavity 313 into a rod chamber and a rodless chamber that are not connected to each other. The rodless chamber is connected to the outside atmosphere. The connecting pipe 4 is sealed and fixedly connected to the end of the connecting arm 311. The connecting pipe 4 has a connecting channel 41. The piston rod of the control piston 32 extends toward the side of the connecting channel 41 and is sealed and movably embedded in the connecting channel 41. It can slide back and forth along the axis of the connecting channel 41. An elastic piston ball 33 that can expand and contract radially is embedded in the inner wall of the air intake channel 312. The spherical surface of the elastic piston ball 33 protrudes into the air intake channel 312 to adjust the effective flow cross-sectional area of ​​the air intake channel 312. The internal cavity of the elastic piston ball 33 is connected to the rod cavity of the mounting cavity 313. Both the internal cavity of the elastic piston ball 33 and the rod cavity of the mounting cavity 313 are filled with a transmission medium.

[0022] In this embodiment, as Figure 2 and Figure 3 As shown, the detection assembly includes a sealing valve plate 21 and an elastic element 22; a circular accommodating cavity is opened at the end of the connecting pipe 4 away from the air intake control assembly 3, and the accommodating cavity is connected to the feed cavity 172 of the heat exchange body 1; the sealing valve plate 21 has a disc-shaped structure adapted to the inner wall of the accommodating cavity, and the outer edge of the sealing valve plate 21 is in a sealing sliding fit with the inner wall of the accommodating cavity, so that the sealing valve plate 21 and the inner wall of the accommodating cavity form a detection cavity 5 that communicates with the connecting channel 41; both the detection cavity 5 and the connecting channel 41 are filled with a transmission medium; the two ends of the elastic element 22 abut against the side surface of the sealing valve plate 21 facing the detection cavity 5 and the inner wall of the accommodating cavity near the connecting channel 41, respectively. Preferably, the elastic element 22 is a cylindrical helical compression spring, and its axis coincides with the axis of the accommodating cavity and the axis of the connecting channel 41 to ensure uniform force and stable operation.

[0023] In this embodiment, the transmission medium is an incompressible liquid such as hydraulic oil, but gas can also be used depending on the working conditions. This embodiment uses hydraulic oil as the transmission medium for explanation. It can be understood that in another alternative embodiment, for working conditions with large viscosity fluctuations and low adjustment accuracy requirements, inert gas can be used as the transmission medium in the internal cavity of the elastic piston ball 33, the rod cavity of the mounting cavity 313, the detection cavity 5, and the connecting channel 41, and the transmission stability can be ensured by pre-charging pressure.

[0024] Preferably, the cross-sectional area of ​​the connecting channel 41 can be designed to be much smaller than that of the sealing valve plate 21, thereby achieving a stroke amplification effect. That is, the stroke of the sealing valve plate 21, after being amplified by the transmission medium within the connecting channel 41, is converted into the stroke of the control piston 32, which in turn drives the elastic piston ball 33 to generate sufficient deformation to precisely adjust the flow opening of the air inlet channel. This effectively avoids the problem in traditional structures where small changes in material viscosity cannot trigger effective flow regulation, leading to a hidden decrease in heat exchange efficiency or ineffective steam energy consumption. This effectively improves the response sensitivity and adjustment accuracy to changes in leachate viscosity. At the same time, by adjusting the ratio of the cross-sectional areas of the sealing valve plate 21 to the connecting channel 41, it can flexibly adapt to leachate treatment conditions with different concentration fluctuation ranges and different treatment scales, realizing a customized design of adjustment amplification factor, further broadening the applicable scenarios and versatility of the structure.

[0025] In addition, the enlarged stroke of the control piston 32 allows for a more linear correspondence between the deformation of the elastic piston ball 33 and the change in material viscosity, making the steam flow rate adjustment process more stable and continuous. This helps to avoid problems such as pressure fluctuations in the heat exchange chamber and thermal shock in the heat exchange tubes caused by sudden changes in the opening degree, further improving the stability of equipment operation and the consistency of evaporation treatment effect.

[0026] Specifically, when the viscosity of the leachate to be treated increases, the static pressure in the feed chamber 172 rises. The pressure acts on the receiving surface of the sealing valve plate 21, overcoming the elastic force of the elastic element 22 and pushing the sealing valve plate 21 to slide closer to the connecting channel 41. This reduces the effective volume of the detection chamber 5, and the transmission medium in the detection chamber 5 is squeezed into the connecting channel 41, thereby pushing the rod of the control piston 32 and causing the control piston 32 to move towards the rodless chamber, thus increasing the effective volume of the rod chamber. At this time, due to the increase in the volume of the rod chamber, the internal pressure decreases, drawing the transmission medium inside the elastic piston ball 33 into the rod chamber, causing the elastic piston ball 33 to contract radially, and the spherical part protruding into the air intake channel 312 to retract, thereby increasing the effective flow opening of the air intake channel 312, and thus increasing the steam flow rate into the heat exchange chamber 13, achieving automatic increase of heat exchange load under high viscosity conditions.

[0027] When the viscosity of the leachate to be treated decreases, the static pressure in the feed chamber 172 decreases, and the pressure acting on the material-facing surface of the sealing valve plate 21 decreases. Under the restoring force of the elastic element 22, the sealing valve plate 21 slides away from the connecting channel 41, increasing the effective volume of the detection chamber 5. The transmission medium in the connecting channel 41 flows back into the detection chamber 5. Under the pressure difference between the rod chamber and the rodless chamber, the control piston 32 moves towards the rod chamber, reducing the effective volume of the rod chamber. This forces the transmission medium in the rod chamber into the internal cavity of the elastic piston ball 33, causing the elastic piston ball 33 to expand radially. The spherical portion protruding into the air intake channel 312 increases, thereby reducing the effective flow opening of the air intake channel 312 and further reducing the steam flow rate entering the heat exchange chamber 13, thus automatically reducing energy consumption under low viscosity conditions.

[0028] In some embodiments of the leachate treatment equipment for the waste transfer station in this example, such as Figure 4 As shown, the outer wall of the control piston 32 and the inner wall of the mounting cavity 313 adopt a surface fit structure to limit the rotational freedom of the control piston 32 in the mounting cavity 313, ensuring that the control piston 32 can only slide back and forth along the axial direction of the mounting cavity 313, avoiding sealing failure and action jamming caused by the deflection of the control piston 32, and improving the stability and reliability of the equipment operation.

[0029] In some embodiments of the leachate treatment equipment for the waste transfer station in this example, such as Figure 2 and Figure 3 As shown, the lower end cover 121 is provided with a connector 1211 that communicates with the feed chamber 172; one end of the connecting pipe 4 near the lower end cover 121 is sealed and inserted into the connector 1211. In this embodiment, by setting the connector 1211, the connecting pipe 4 can be disassembled and maintained, ensuring the convenience of equipment assembly.

[0030] In some embodiments of the leachate treatment equipment for the waste transfer station in this example, such as Figure 4 As shown, the outer wall of the elastic piston ball 33 is provided with an integrally formed connecting part 331, and the connecting part 331 is provided with a through hole communicating with the internal cavity of the elastic piston ball 33. A flexible hose 34 is provided between the connecting part 331 and the control piston 32. One end of the flexible hose 34 is sealed and inserted into the through hole of the connecting part 331, and is sealed and communicated with the internal cavity of the elastic piston ball 33. The other end of the flexible hose 34 is sealed and inserted into the interior of the control piston 32, and is sealed and communicated with the rod cavity of the mounting cavity 313. By providing the flexible hose 34, a sealed communication between the elastic piston ball 33 and the rod cavity is achieved, avoiding leakage of the transmission medium, and at the same time adapting to the reciprocating sliding of the control piston 32, ensuring the stability and sealing of the transmission.

[0031] The above description is only a preferred embodiment of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of this patent application are included within the protection scope of this patent application.

Claims

1. A leachate treatment device for a waste transfer station, characterized in that, The device includes a heat exchange body, which has a heat exchange cavity and multiple material channels located within the heat exchange cavity; the heat exchange cavity is connected to an air inlet and an exhaust outlet; and the heat exchange body has a feed inlet and a discharge outlet at both ends that communicate with the multiple material channels. The heat exchanger body is equipped with a detection component for detecting the viscosity of the material at the corresponding feed inlet position; the air inlet is connected to an air intake control component; the air intake control component is connected to the detection component through a connecting pipe to control the steam flow rate entering the heat exchange chamber according to the material viscosity. The intake control assembly includes an intake valve body with an intake channel; the intake valve body is provided with a connecting arm, the connecting arm has an installation cavity, a control piston is movably disposed in the installation cavity, the control piston divides the installation cavity into a rod-side cavity and a rodless cavity, wherein the rodless cavity is in communication with the outside atmosphere; a connecting pipe is connected to the end of the connecting arm, the connecting pipe has a connecting channel; the piston rod of the control piston is movably embedded in the connecting channel and can reciprocate along the axial direction of the connecting channel; An elastic piston ball is embedded in the air intake channel; the interior of the elastic piston ball is connected to the rod chamber; both the elastic piston ball and the rod chamber are filled with a transmission medium. The detection assembly includes a sealing valve plate and an elastic element; the end of the connecting pipe away from the air intake control assembly is provided with a receiving cavity; the sealing valve plate is movably and sealingly disposed in the receiving cavity, thereby forming a detection cavity communicating with the connecting channel; the two ends of the elastic element abut against the inner walls of the sealing valve plate and the receiving cavity, respectively. The elastic piston ball is provided with a connecting part; a flexible hose is provided between the connecting part and the control piston; one end of the flexible hose is sealed and inserted into the connecting part and communicates with the interior of the elastic piston ball; the other end of the flexible hose is sealed and passes through the control piston and communicates with the rod chamber.

2. The leachate treatment equipment for a waste transfer station according to claim 1, characterized in that, The elastic element is a spring.

3. The leachate treatment equipment for a waste transfer station according to claim 1, characterized in that, The control piston mates with the inner wall of the mounting cavity to restrict the rotational freedom of the control piston.

4. The leachate treatment equipment for a waste transfer station according to claim 1, characterized in that, The heat exchange body includes a heat exchange shell, a lower end cover, and an upper end cover; the upper end cover and the lower end cover are respectively fixed to the upper and lower ends of the heat exchange shell; an upper partition is provided between the upper end cover and the upper end of the heat exchange shell; a lower partition is provided between the lower end cover and the lower end of the heat exchange shell; a discharge chamber communicating with the discharge port is formed between the upper end cover, the upper partition, and the heat exchange shell; a feed chamber communicating with the feed inlet is formed between the lower end cover, the lower partition, and the heat exchange shell; the heat exchange chamber is formed between the upper partition, the lower partition, and the heat exchange shell. Multiple heat exchange tubes are connected between the upper and lower partitions; the upper and lower ends of each heat exchange tube are respectively connected to the discharge chamber and the feed chamber; the material channel is formed inside the heat exchange tube.

5. The leachate treatment equipment for a waste transfer station according to claim 4, characterized in that, The lower end cover is provided with a connector that communicates with the feed chamber; one end of the connecting pipe near the lower end cover is sealed and inserted into the connector.

Images