Equipment for compressed air energy storage by using underground gasification cavity

Abstract

The invention belongs to the field of coal underground gasification development, and discloses a device for compressed air energy storage by using an underground gasification cavity, the device comprises a leading-in pipe, a leading-out pipe, a compressor system and an air release device, the leading-in pipe is tripped into a leading-in well to communicate the compressor system with the underground gasification cavity, the leading-out pipe is tripped into a leading-out well to communicate the compressor system with the underground gasification cavity, and the air release device is connected with the leading-out pipe. The air release device is communicated with the underground gasification cavity, a filter cartridge for filtering released gas is arranged between the eduction pipe and the air release device, and the eduction pipe is connected with a negative pressure suction cleaning device; the negative pressure suction cleaning device comprises a plurality of sets of cleaning joints used for cleaning the inner wall of the eduction tube and a negative pressure suction system used for sucking the cleaning joints. The underground gasification cavity is used for storing energy for compressed air, the inner wall of the eduction pipe in the eduction well can be cleaned on the premise that normal compression energy storage and release utilization of air are not affected, and convenience is provided for air energy storage.

Description

Technical Field

[0001] The present disclosure belongs to the field of underground coal gasification development, and in particular relates to a device for storing compressed air energy using an underground gasification cavity. Background Art

[0002] The Underground Compressed Air Energy Storage (UCAES) system stores and releases energy by converting surplus electricity into compressed air. During peak energy demand, the stored compressed air can be released to drive generators and supply the grid. During low energy demand periods, electricity can be used to drive compressors, recompressing the air and storing it in underground vaporization chambers, regenerating and storing energy.

[0003] Underground Coal Gasification (UCG) is an energy extraction technology whose basic principle is to convert coal or other carbonaceous materials into synthesis gas (syngas) underground. During the UCG process, the coal is ignited and partially burned, generating high temperatures and pressure, which trigger the coal's pyrolysis and gasification reactions. The gasification reaction converts the coal into combustible gas, the main components of which are carbon monoxide (CO), hydrogen (H2), and some other gases. Therefore, after mining using UCG is completed, an underground gasification cavity of a certain size is formed.

[0004] Therefore, underground gasification chambers can be used to compress air for energy storage, thereby fully utilizing existing resources and saving costs. However, since coal tar and other substances may be present at a certain humidity within the underground gasification chamber after mining, the air released and flowing through the underground gasification chamber will gradually accumulate on the inner walls of the pipelines passing through it. Coal tar contains various organic compounds, some of which are corrosive. This can cause pipeline corrosion, increase the workload of pipeline cleaning, and affect the operation and use of air compression energy storage.

[0005] Therefore, it is necessary to provide a device for storing compressed air energy using an underground gasification cavity to solve the above problems. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the purpose of the present disclosure is to provide a device for storing compressed air energy using an underground gasification cavity.

[0007] To achieve the above objectives, the present disclosure provides the following technical solutions:

[0008] A device for storing compressed air energy using an underground gasification cavity, comprising an inlet pipe, an outlet pipe, a compressor system, and an air release device.

[0009] The inlet pipe is lowered into the well to connect the compressor system and the underground gasification cavity.

[0010] The outlet pipe is lowered into the outlet well, connecting the air release device and the underground gasification cavity. A filter cartridge is provided between the outlet pipe and the air release device to filter the released gas.

[0011] The outlet pipe is connected to a negative pressure suction cleaning device, which includes multiple cleaning sections for cleaning the inner wall of the outlet pipe and a negative pressure suction system for suctioning the cleaning sections.

[0012] Furthermore, the cleaning section includes a retaining seat, a guide tube, a scraping system and a resetting connector.

[0013] The retaining seat includes an outer ring seat and an inner ring seat that are coaxial and fixedly connected.

[0014] The outer ring seat is fixedly assembled with the inner wall of the outlet pipe.

[0015] The two ends of the inner ring seat axis are fixedly connected to one end of the two guide tubes.

[0016] The scraping system is sleeved on the outer wall of the guide tube and is connected to the inner ring seat through a reset connector.

[0017] Furthermore, the outer wall of the guide tube is provided with axial ribs.

[0018] The reset connector comprises a sliding sleeve slidably arranged on the convex rib, a drainage fan is rotatably mounted on the outer surface of the sliding sleeve, and the sliding sleeve is connected to the inner ring seat via a reset spring.

[0019] Furthermore, a slideway slot is provided on the wall of the guide tube, and the scraping system includes a suction surface ring, a first retaining ring, a suction side ring and a scraping assembly.

[0020] One end of the suction surface ring is fixedly connected to the first retaining ring, and the other end is fixedly connected to the suction side ring.

[0021] The suction surface ring and the suction side ring are provided with a connected cavity inside. The cavity of the suction surface ring is connected to the outer surface, and the cavity of the suction side ring is connected to the connecting main pipe located in the guide pipe through a connecting branch pipe provided through the slideway seam.

[0022] The first retaining ring is fixedly connected to the sliding sleeve,

[0023] The scraping assembly is rotatably connected to the outer wall of the suction surface ring and is fixedly assembled with the shaft end face of the drainage fan.

[0024] The connecting main pipe is connected with the negative pressure suction system through a telescopic connecting piece.

[0025] Furthermore, communicating cavities are uniformly distributed axially and circumferentially in the ring wall of the suction surface ring, and suction holes communicating with the communicating cavities are provided on the outer wall of the suction surface ring.

[0026] Furthermore, the suction side ring includes a connecting hole, a first diversion chamber and a second diversion chamber. The connecting hole and the connecting chamber are connected in a one-to-one correspondence. The connecting chamber is equally divided into connecting chamber groups. The first diversion chamber is equally divided into diversion chamber groups. The second diversion chamber is connected in a one-to-one correspondence with the connecting chamber group. The second diversion chamber is connected to the connecting main pipe through a connecting branch pipe.

[0027] Furthermore, the scraping assembly includes a second fixed ring and a scraping plate, which are arranged in a circle on the outer wall of the suction surface ring. The second fixed ring loads and assembles the two ends of the scraping plate to form a scraping frame. One end of the scraping frame is fixedly assembled with the axial end face of the drainage fan, and the outer diameter of the circle formed by the scraping plate is larger than the outer diameter of the second fixed ring.

[0028] Furthermore, the direction of the acute angle between the scraping plate and the outer wall of the suction surface ring is consistent with the rotation direction of the drainage fan.

[0029] Furthermore, a flow-cutting edge block is provided on one side of the acute angle formed by the scraping plate and the outer wall of the suction surface ring, and the flow-cutting edge block is in a triangular prism structure.

[0030] Furthermore, the contact surfaces of the scraping plate and the suction surface ring are respectively provided with grinding heads that are staggered.

[0031] Furthermore, the telescopic connecting piece includes a connecting outer tube, a connecting inner tube and a piston sleeve. The connecting outer tube is connected to the connecting main tube, and the connecting inner tube is connected to the negative pressure suction system. The piston sleeve is sleeved on one end of the connecting inner tube and is movably sealed and connected to the inside of the connecting outer tube.

[0032] The technical effects and advantages of the present disclosure are as follows:

[0033] The present invention utilizes the large storage capacity provided by the underground gasification cavity to store compressed air on a large scale, and through the arrangement of the negative pressure suction cleaning device and the filter cartridge, it can filter the coal tar and other substances in the released gas, thereby ensuring the cleanliness of the air released by the air release device, and avoiding the presence of coal tar and other substances in the release pipeline other than the outlet well, thereby avoiding corrosion; in addition, it can also clean the inner wall of the outlet pipe in the outlet well without affecting the normal compression energy storage and release utilization of the air, thereby avoiding shutdown operations, and cleaning the inner wall of the pipeline of the outlet well on a large scale, thereby ensuring the full utilization of the underground gasification cavity and the convenience of air compression energy storage and release utilization.

[0034] Other features and advantages of the present disclosure will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present disclosure. The purposes and other advantages of the present disclosure can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic structural diagram of a device for storing compressed air energy using an underground gasification cavity disclosed herein;

[0036] Figure 2 Schematic diagram of the structure of the negative pressure suction cleaning device disclosed in the present invention;

[0037] Figure 3 It is a schematic structural diagram of the cleaning section disclosed herein;

[0038] Figure 4 Schematic diagram of the structure of the retaining seat disclosed in the present invention;

[0039] Figure 5 Schematic diagram of the scraping system structure disclosed in this invention Figure 1 ;

[0040] Figure 6 Schematic diagram of the scraping system structure disclosed in this invention Figure 2 ;

[0041] Figure 7 This is a schematic diagram of the suction side ring structure disclosed in the present invention;

[0042] Figure 8 This is a schematic structural diagram of the scraping assembly disclosed herein;

[0043] Figure 9 Schematic diagram of the grinding head structure disclosed in the present invention;

[0044] Figure 10 This is a schematic structural diagram of the telescopic connecting piece disclosed herein;

[0045] Figure 11 This is a schematic diagram of the connecting main pipe and connecting branch pipe structure disclosed in the present invention.

[0046] Figure numerals: 1, underground gasification cavity; 2, inlet well; 3, outlet well; 4, inlet pipe; 5, compressor system; 6, outlet pipe; 7, air release device; 8, negative pressure suction cleaning device; 9, cleaning section; 91, retaining seat; 92, guide pipe; 93, scraping system; 94, reset connector; 911, outer ring seat; 912, inner ring seat; 921, rib; 922, slideway seam; 931, suction surface ring; 932, first retaining ring; 933, suction side ring; 934, scraping assembly; 935, connecting Branch pipe; 936, connecting main pipe; 937, grinding head; 941, return spring; 942, sliding sleeve; 943, drainage fan; 9311, connecting chamber; 9312, suction hole; 9331, connecting hole; 9332, first diversion chamber; 9333, second diversion chamber; 9341, second retaining ring; 9342, scraper plate; 9343, cutting edge block; 10, negative pressure suction system; 11, telescopic connecting piece; 12, filter cartridge; 111, connecting outer pipe; 112, connecting inner pipe; 113, piston sleeve. DETAILED DESCRIPTION

[0047] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0048] like Figure 1 As shown, the present disclosure provides a device for compressed air energy storage using an underground gasification cavity, including an inlet pipe 4, an outlet pipe 6, a compressor system 5, and an air release device 7.

[0049] The inlet pipe 4 is lowered into the inlet well 2, connecting the compressor system 5 with the underground gasification cavity 1.

[0050] The outlet pipe 6 is lowered into the outlet well 3, connecting the air release device 7 and the underground gasification cavity 1. A filter cartridge 12 for filtering the released gas is provided between the outlet pipe 6 and the air release device 7.

[0051] The outlet pipe 6 is connected to the negative pressure suction cleaning device 8, such as Figure 2 As shown, the negative pressure suction cleaning device 8 includes a plurality of cleaning sections 9 for cleaning the inner wall of the outlet pipe 6 and a negative pressure suction system 10 for suctioning the cleaning sections 9 .

[0052] Among them, the filter cartridge 12 is used to filter coal tar and other substances in the released gas, ensuring the cleanliness of the air released by the air release device 7, avoiding the presence of coal tar and other substances in the release pipeline other than the outlet well 3, thereby avoiding corrosion; and the design of the negative pressure suction cleaning device 8 can clean the inner wall of the outlet pipe 6 without affecting the normal compression, energy storage and release utilization of the air, thereby avoiding shutdown operations and large-scale cleaning of the inner wall of the outlet pipe 6, thereby ensuring full utilization of the underground gasification cavity 1 and ensuring the convenience of air compression, energy storage and release utilization.

[0053] In some embodiments of the present disclosure, Figure 3 As shown, the cleaning section 9 includes a retaining seat 91, a guide tube 92, a scraping system 93 and a reset connector 94. Figure 4 As shown, the retaining seat 91 includes an outer ring seat 911 and an inner ring seat 912 that are coaxial and fixedly connected. The outer ring seat 911 is fixedly assembled with the inner wall of the outlet tube 6. The two ends of the axis of the inner ring seat 912 are respectively fixedly connected to one end of the two guide tubes 92. The scraping system 93 is sleeved on the outer wall of the guide tube 92, and the scraping system 93 is connected to the inner ring seat 912 through a reset connector 94.

[0054] It should be noted that the cleaning section 9 is arranged at the lower end of each section of the outlet pipe 6. When air is released, the energy of the released air can drive the scraping system 93 to move upward, thereby comprehensively cleaning the pipe wall of the outlet pipe 6. After the air release is completed, it moves downward and resets under the action of the reset connector 94, and comprehensively cleans the pipe wall of the outlet pipe 6 again, and promptly removes substances such as coal tar attached to the pipe wall of the outlet pipe 6 to avoid long-term accumulation and aggregation and adsorption on the pipe wall of the outlet pipe 6, which corrodes and damages the outlet pipe 6.

[0055] In some embodiments of the present disclosure, Figure 4 As shown, the outer wall of the guide tube 92 is provided with an axial rib 921. The reset connector 94 includes a sleeve 942 slidably mounted on the rib 921. A drainage fan 943 is rotatably mounted on the outer surface of the sleeve 942. The sleeve 942 is connected to the inner ring seat 912 via a reset spring 941. When air is released, the air pushes the drainage fan 943 to rotate, driving the sleeve 942 axially, prompting the scraping system 93 to completely scrape and clean the inner wall of the outlet tube 6.

[0056] In some embodiments of the present disclosure, Figure 4 As shown, a slideway slot 922 is provided on the wall of the guide tube 92. Figure 5 、 6As shown, the scraping system 93 includes a suction surface ring 931, a first retaining ring 932, a suction side ring 933 and a scraping assembly 934. One end of the suction surface ring 931 is fixedly connected to the first retaining ring 932, and the other end is fixedly connected to the suction side ring 933. The suction surface ring 931 and the suction side ring 933 are internally provided with a communicating cavity. The cavity of the suction surface ring 931 is communicated with the outer surface, and the cavity of the suction side ring 933 is connected to the communicating main pipe 936 located in the guide pipe 92 through the communicating branch pipe 935 provided through the slideway slot 922. The connecting structure of the communicating main pipe 936 and the communicating branch pipe 935 is shown in FIG. Figure 11 As shown, the first retaining ring 932 is fixedly connected to the sliding sleeve 942, the scraping assembly 934 is rotatably connected to the outer wall of the suction surface ring 931, and is fixedly assembled with the axial end face of the drainage fan 943. The connecting main pipe 936 is connected to the negative pressure suction system 10 via the telescopic connecting piece 11. The connecting main pipe 936 is limited by the slideway gap 922, and the suction surface ring 931 does not rotate, but only moves axially. The scraping system 93 rotates with the rotation of the drainage fan 943 and cleans and scrapes the wall of the outlet pipe 6. In addition, the scraping system 93 has a tendency to scrape and press scraped coal tar and other substances toward the outer surface of the suction surface ring 931, further cooperating with the negative pressure suction system 10 to discharge the scraped coal tar and other substances.

[0057] In some embodiments of the present disclosure, Figure 7 As shown, the suction surface ring 933 has a ring wall provided with connecting cavities 9311 that are evenly distributed axially and circumferentially, and an outer wall of the suction surface ring 933 has suction holes 9312 that are connected to the connecting cavities 9311 .

[0058] In some embodiments of the present disclosure, Figure 7 As shown, the suction side ring 933 includes a connecting hole 9331, a first diverter cavity 9332 and a second diverter cavity 9333. The connecting hole 9331 is connected to the connecting cavity 9311 in a one-to-one manner. The connecting cavity 9311 is divided into connecting cavity groups. The first diverter cavity 9332 is connected to the connecting cavity groups in a one-to-one manner. The first diverter cavity 9332 is divided into diverter cavity groups. The second diverter cavity 9333 is connected to the diverter cavity groups in a one-to-one manner. The second diverter cavity 9333 is connected to the connecting main pipe 936 through a connecting branch pipe 935.

[0059] In some embodiments of the present disclosure, Figure 8 As shown, the scraping assembly 934 includes a second fixed ring 9341 and a scraping plate 9342. The scraping plates 9342 are arranged in a circle on the outer wall of the suction surface ring 931. The second fixed ring 9341 carries and assembles the two ends of the scraping plates 9342 to form a scraping frame. One end of the scraping frame is fixedly assembled with the axial end face of the drainage fan 943. The outer diameter of the circle formed by the scraping plate 9342 is larger than the outer diameter of the second fixed ring 9341.

[0060] In some embodiments of the present disclosure, the direction of the acute angle between the scraper plate 9342 and the outer wall of the suction surface ring 931 is consistent with the rotation direction of the drainage fan 943. Figure 8 As shown, when observed from the left side, the axial rotation of the scraper plate 9342 is clockwise, scraping and cleaning the inner wall of the guide tube 6.

[0061] In some embodiments of the present disclosure, Figure 8 As shown, the side of the scraper plate 9342 that forms an acute angle with the outer wall of the suction surface ring 931 is further provided with a cutting edge block 9342. The cutting edge block 9342 has a triangular prism structure. The side of the cutting edge block 9342 that is closest to the suction surface ring 931 has a curved surface structure consistent with the suction surface ring 931, so that it can scrape and clean coal tar and other substances while also scraping and pressuring them toward the suction hole 9312.

[0062] In some embodiments of the present disclosure, Figure 9 As shown, the contact surfaces of the scraper plate 9342 and the suction surface ring 931 are respectively provided with staggered grinding heads 937 so as to crush the formed particles or the materials stuck on the suction hole 9312 to avoid clogging the suction hole 9312.

[0063] In some embodiments of the present disclosure, Figure 10 As shown, the telescopic connecting piece 11 includes a connecting outer tube 111, a connecting inner tube 112 and a piston sleeve 113. The connecting outer tube 111 is connected to the connecting main tube 936, and the connecting inner tube 112 is connected to the negative pressure suction system 10. The piston sleeve 113 is sleeved on one end of the connecting inner tube 112 and is movably and sealedly connected to the inside of the connecting outer tube 111, thereby meeting the requirement of axial movement of the connecting main tube 936.

[0064] The specific implementation includes the following steps:

[0065] S1: Check the sealing performance of the underground gasification cavity 1;

[0066] S2: Use the inlet well of the underground gasification cavity 1 as the inlet well 2, and the outlet well as the outlet well 3, and assemble the inlet pipe 4, outlet pipe 6, filter cartridge 10, cleaning section 9, compressor system 5, air release device 7 and negative pressure suction system 10 respectively;

[0067] S3: The compressor system 5 compresses air and introduces it into the underground gasification cavity 1 for energy storage;

[0068] S4: The air release device 7 regulates the release of the stored compressed air, wherein each time the compressed air is released, the wall of the outlet pipe 6 can be cleaned synchronously and promptly.

[0069] Finally, it should be noted that the above is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A device for storing compressed air energy using an underground gasification cavity, characterized in that: It includes an inlet pipe (4), an outlet pipe (6), a compressor system (5) and an air release device (7). The introduction pipe (4) is lowered into the introduction well (2) to connect the compressor system (5) with the underground gasification cavity (1). The outlet pipe (6) is lowered into the outlet well (3) to connect the air release device (7) and the underground gasification cavity (1). A filter cartridge (12) for filtering the released gas is provided between the outlet pipe (6) and the air release device (7). The outlet pipe (6) is connected to a negative pressure suction cleaning device (8), which comprises a plurality of cleaning sections (9) for cleaning the inner wall of the outlet pipe (6) and a negative pressure suction system (10) for suctioning the cleaning sections (9).

2. The device for storing compressed air energy using an underground gasification cavity according to claim 1, characterized in that: The cleaning section (9) comprises a retaining seat (91), a guide tube (92), a scraping system (93) and a resetting connector (94). The retaining seat (91) comprises an outer ring seat (911) and an inner ring seat (912) which are coaxial and fixedly connected. The outer ring seat (911) is fixedly assembled with the inner wall of the outlet pipe (6). The two ends of the axis of the inner ring seat (912) are respectively fixedly connected to one end of the two guide tubes (92). The scraping system (93) is sleeved on the outer wall of the guide tube (92), and the scraping system (93) is connected to the inner ring seat (912) via a reset connector (94).

3. The device for storing compressed air energy using an underground gasification cavity according to claim 2, characterized in that: The outer wall of the guide tube (92) is provided with axial ribs (921). The reset connector (94) includes a sliding sleeve (942) slidably arranged on the rib (921), a guide fan (943) is rotatably mounted on the outer surface of the sliding sleeve (942), and the sliding sleeve (942) is connected to the inner ring seat (912) via a reset spring (941).

4. The device for storing compressed air energy using an underground gasification cavity according to claim 3, characterized in that: The guide tube (92) has a slideway slit (922) formed on its wall. The scraping system (93) includes a suction surface ring (931), a first retaining ring (932), a suction side ring (933), and a scraping assembly (934). One end of the suction surface ring (931) is fixedly connected to the first retaining ring (932), and the other end is fixedly connected to the suction side ring (933). The suction surface ring (931) and the suction side ring (933) are provided with a communicating cavity inside. The cavity of the suction surface ring (931) is communicated with the outer surface. The cavity of the suction side ring (933) is communicated with the communicating main pipe (936) located in the guide pipe (92) through a communicating branch pipe (935) provided through the slideway slit (922). The first retaining ring (932) is fixedly connected to the sliding sleeve (942). The scraping assembly (934) is rotatably connected to the outer wall of the suction surface ring (931) and is fixedly assembled with the axial end face of the drainage fan (943). The connecting main pipe (936) is connected to the negative pressure suction system (10) via a telescopic connecting piece (11).

5. The device for storing compressed air energy using an underground gasification cavity according to claim 4, characterized in that: The suction surface ring (933) has a ring wall provided with a connecting cavity (9311) that is evenly distributed axially and circumferentially, and an outer wall of the suction surface ring (933) has a suction hole (9312) that is connected to the connecting cavity (9311).

6. The device for storing compressed air energy using an underground gasification cavity according to claim 5, characterized in that: The suction side ring (933) includes a connecting hole (9331), a first diverter cavity (9332) and a second diverter cavity (9333), the connecting hole (9331) is connected to the connecting cavity (9311) in a one-to-one correspondence, the connecting cavity (9311) is equally divided into connecting cavity groups, the first diverter cavity (9332) is connected to the connecting cavity group in a one-to-one correspondence, the first diverter cavity (9332) is equally divided into diverter cavity groups, the second diverter cavity (9333) is connected to the diverter cavity group in a one-to-one correspondence, and the second diverter cavity (9333) is connected to the connecting main pipe (936) through a connecting branch pipe (935).

7. The device for storing compressed air energy using an underground gasification cavity according to claim 4, characterized in that: The scraping assembly (934) includes a second fixed ring (9341) and a scraping plate (9342), and the scraping plates (9342) are arranged in a circular shape on the outer wall of the suction surface ring (931). The second fixed ring (9341) carries and assembles the two ends of the scraping plates (9342) to form a scraping frame, and one end of the scraping frame is fixedly assembled with the axial end face of the drainage fan (943). The outer diameter of the circle formed by the scraping plates (9342) is larger than the outer diameter of the second fixed ring (9341).

8. The device for storing compressed air energy using an underground gasification cavity according to claim 7, characterized in that: The direction of the acute angle formed between the scraper plate (9342) and the outer wall of the suction surface ring (931) is consistent with the rotation direction of the drainage fan (943).

9. The device for storing compressed air energy using an underground gasification cavity according to claim 8, characterized in that: A cutting edge block (9342) is further provided on the side of the acute angle formed between the scraping plate (9342) and the outer wall of the suction surface ring (931), and the cutting edge block (9342) is a triangular prism structure.

10. The device for storing compressed air energy using an underground gasification cavity according to claim 7, characterized in that: The contact surfaces of the scraping plate (9342) and the suction surface ring (931) are respectively provided with grinding heads (937) distributed in an offset manner.

11. The device for storing compressed air energy using an underground gasification cavity according to claim 4, characterized in that: The telescopic connecting piece (11) includes a connecting outer tube (111), a connecting inner tube (112) and a piston sleeve (113), wherein the connecting outer tube (111) is connected to the connecting main tube (936), and the connecting inner tube (112) is connected to the negative pressure suction system (10), and the piston sleeve (113) is sleeved on one end of the connecting inner tube (112) and is movably sealed with the inside of the connecting outer tube (111).

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