Metal seal gas production wellhead device

Abstract

The invention relates to the technical field of underground gas production, and discloses a metal sealing gas production wellhead device which comprises a body. A housing; the filtering assembly is used for circularly filtering gas in the wellhead; the self-discharging assembly is used for automatically discharging impurity particles attached to the filtering assembly; the filtering assembly comprises a screening device and an indexing rotating device; and the screening device is used for filtering gas impurities in the well. According to the metal sealing gas production wellhead device, drum-type double-layer filtering can be achieved through the arranged filtering assembly, so that it can be guaranteed that impurity particles in mined gas can be greatly filtered out, and the purity of the extracted gas is guaranteed. And the indexing rotation of the circular filter cartridge can be controlled by utilizing the indexing rotation device, so that the gradually blocked circular filter cartridge can be rotated, and clean filter holes face the underground again, and therefore, circulating automatic anti-blocking screening is carried out, and the operation stability of the gas production wellhead device is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of underground gas production, in particular to a metal-sealed gas production wellhead device. Background Art

[0002] At present, underground coal gasification project is a new field. The project can effectively alleviate the current situation of domestic natural gas supply and demand. However, the composition of the output gas is complex, corrosive and high in temperature, which is a test for equipping a gas wellhead device that is corrosion-resistant, high-temperature-resistant and has a long service life.

[0003] At present, when the traditional wellhead device, that is, the Christmas tree, is used to mine underground gas, the gas will be extracted along the pipeline. During the mining process, the underground gas needs to be further filtered, but the traditional filtering method only relies on the filter to perform initial filtration to filter underground sand and gravel, as well as some impurities in the gas. Because mining is a long-term process, this type of filtration requires the filter to be replaced or cleaned from time to time. Otherwise, the filter will be blocked, which will make it difficult to extract the internal gas and the pressure of the pipeline will be high, which will have a certain impact on the safety of the wellhead. Therefore, a metal sealed gas wellhead device is proposed to solve the above-mentioned problems. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a metal-sealed gas wellhead device, which solves the problem in the prior art that the gas inside the gas well cannot be filtered and cleaned in a timely and effective manner, and requires irregular manual replacement and maintenance, which is time-consuming and labor-intensive, and may also pose a certain degree of safety hazard to the wellhead.

[0006] (II) Technical solution

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a metal-sealed gas wellhead device, comprising a main body; a shell; a filter component for circulating and filtering the gas in the wellhead; a self-draining component for automatically discharging foreign particles attached to the filter component; the filter component comprises a screening device and a dividing and rotating device; the screening device is used to filter gas impurities in the well; the dividing and rotating device is used to control the dividing and rotating of the internal screening device; the filter component is arranged inside the shell, and the self-draining component is arranged inside the main body below the screening device.

[0008] Preferably, the screening device comprises a circular filter cartridge, which is rotatably connected to the interior of the shell, and a sliding plate is slidably connected to the inner wall of the shell, and the bottom of the sliding plate abuts against the circular filter cartridge.

[0009] Preferably, a positioning plate is fixedly connected inside the shell, and two arc-shaped round rods are fixedly connected to the positioning plate. The two arc-shaped round rods are fixed inside the shell through connecting parts, and arc springs are sleeved on the surfaces of the arc-shaped round rods. The two ends of the arc springs are respectively connected to the sliding plate and the positioning plate.

[0010] Preferably, two groups of arc-shaped round rods and arc-shaped springs are provided, and the two groups of arc-shaped round rods and arc-shaped springs are symmetrically distributed about the center line of the circular filter cartridge.

[0011] Preferably, the indexing rotation device includes a stretching link, one end of the stretching link is rotatably connected to the sliding plate, the other end of the stretching link is rotatably connected to the lifting shaft, the lifting shaft is fixedly connected to a sliding shaft, the sliding shaft is slidably connected to the main body, the bottom of the sliding shaft is connected to a sliding rack, and a one-way device is provided on the sliding rack.

[0012] Preferably, the one-way device includes a central shaft, a connecting ring is fixedly connected to the central shaft, four ratchet clips are rotatably connected to the connecting ring, a tension spring is connected to the ratchet clip, the bottom of the tension spring is connected to the central shaft, an outer tooth sleeve is clamped on the ratchet clip, the outer surface of the outer tooth sleeve is provided with teeth, the sliding rack is engaged with the surface teeth of the outer tooth sleeve, the central shaft is fixed to the side of the circular filter cartridge, a partition is provided inside the shell, and the one-way device is located in a sealed cavity formed between the partition and the shell.

[0013] Preferably, the self-discharging component includes a rotating shaft, a plurality of blades are arranged on the surface of the rotating shaft, the rotating shaft is rotatably connected to the inside of the main body through a connecting piece, a cam plate is fixedly connected to the top of the rotating shaft, a contact plate is abutted on the surface of the cam plate, a pull plate is fixedly connected to the top of the contact plate, two guide rods are fixedly connected to one side of the pull plate, and an extrusion spring is sleeved on the surface of the guide rod.

[0014] Preferably, an upper sealing plate is provided inside the shell, a push plate is slidably connected to the shell, a push plate is fixedly connected to the push plate, a contraction spring is sleeved on the surface of the push rod, one end of the contraction spring is connected to the shell, and the other end of the contraction spring is connected to the upper sealing plate, and an accumulation box is provided on the shell below the push plate.

[0015] Preferably, one end of the push rod passes through the shell and is flush with the side surface of the upper sealing plate, and a discharge chute is provided inside the accumulation box.

[0016] (III) Beneficial effects

[0017] Compared with the prior art, the present invention provides a metal-sealed gas wellhead device having the following features:

[0018] Beneficial effects:

[0019] 1. The metal-sealed gas wellhead device can achieve drum-type double-layer filtration through the filter assembly, thereby ensuring that the mined gas can greatly filter out the impurity particles therein and ensure the purity of the extracted gas. In addition, the indexing rotation device can control the indexing rotation of the circular filter cartridge, so that the gradually blocked circular filter cartridge can be rotated and the clean filter holes can be directed back to the well, so as to perform cyclic automatic anti-blocking screening and ensure the operating stability of the gas wellhead device.

[0020] 2. The metal-sealed gas wellhead device can automatically clean and discharge the filtered impurities through the self-draining components, thereby ensuring the cleanliness of the internal cavity and further improving the operational stability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of a metal-sealed gas production wellhead device proposed by the present invention;

[0022] Figure 2 A schematic diagram of the cross-sectional structure of a shell of a metal-sealed gas production wellhead device proposed by the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of a filter component of a metal-sealed gas production wellhead device proposed by the present invention;

[0024] Figure 4 This is a schematic diagram of the connection structure of a lifting shaft of a metal-sealed gas production wellhead device proposed by the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of a one-way device of a metal-sealed gas production wellhead device proposed by the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of a self-draining component of a metal-sealed gas production wellhead device proposed by the present invention;

[0027] Figure 7 The present invention provides a schematic diagram of the connection structure of an accumulation box of a metal-sealed gas production wellhead device.

[0028] In the figure: 1. main body; 2. shell; 3. filtering component; 301. circular filter cartridge; 302. sliding plate; 303. arc rod; 304. arc spring; 305. stretching connecting rod; 306. positioning plate; 307. lifting shaft; 308. sliding shaft rod; 309. sliding rack; 310. one-way device; 3101. outer gear sleeve; 3102. ratchet; 3103. tension spring; 3104. center shaft; 3105. connecting ring; 311. partition; 4. self-draining component; 401. rotating shaft; 402. cam plate; 403. pull plate; 404. guide rod; 405. extrusion spring; 406. contact plate; 407. push plate; 408. upper sealing plate; 409. ejector rod; 410. contraction spring; 411. accumulation box; 412. discharge chute. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-Figure 7 A metal-sealed gas wellhead device comprises a main body 1; a shell 2; a filter component 3 for circulating and filtering the gas in the wellhead; a self-draining component 4 for automatically discharging the impurity particles attached to the filter component 3; the filter component 3 comprises a screening device and a dividing and rotating device; the screening device is used to filter the gas impurities in the well; the dividing and rotating device is used to control the dividing and rotating of the internal screening device; the filter component 3 is arranged inside the shell 2, and the self-draining component 4 is arranged inside the main body 1 below the screening device.

[0031] In this embodiment, the filtration device includes a circular filter cartridge 301, which is rotatably connected to the inside of the housing 2, and a sliding plate 302 is slidably connected to the inner wall of the housing 2, and the bottom of the sliding plate 302 abuts against the circular filter cartridge 301. Double-layer filtration is performed through the circular filter cartridge 301, because the gas passes through the circular filter cartridge 301, enters the inside of the circular filter cartridge 301, and is discharged from the top of the circular filter cartridge 301, so a double-layer filter screen is directly formed.

[0032] Furthermore, a positioning plate 306 is fixedly connected in the housing 2, and two arc-shaped round rods 303 are fixedly connected to the positioning plate 306. The two arc-shaped round rods 303 are fixed inside the housing 2 through a connecting piece, and arc springs 304 are sleeved on the surface of the arc-shaped round rods 303. The two ends of the arc springs 304 are respectively connected to the sliding plate 302 and the positioning plate 306. There are two groups of arc-shaped round rods 303 and arc springs 304, and the two groups of arc-shaped round rods 303 and arc springs 304 are symmetrically distributed about the center line of the circular filter cartridge 301. The arc spring 304 and the arc rod 303 are provided to provide limited sliding of the sliding plate 302, which can only limit its sliding along the inner wall of the circular filter cartridge 301 and the shell 2, and when the circular filter cartridge 301 is gradually blocked, the sliding plate 302 will slide with the increase of air pressure, and use this as a power to drive the self-rotation of the circular filter cartridge 301. When the sliding plate 302 is depressurized and reset, it will drive it to scrape and clean the surface of the circular filter cartridge 301, and self-clean the impurities attached to the circular filter cartridge 301, and finally deposit them at the four corners of the shell 2, so as to facilitate the subsequent self-draining component 4 to self-drain the impurities.

[0033] Furthermore, the indexing rotation device includes a stretching link 305, one end of which is rotatably connected to the sliding plate 302, and the other end of which is rotatably connected to the lifting shaft 307, and the lifting shaft 307 is fixedly connected to the sliding shaft 308, and the sliding shaft 308 is slidably connected to the main body 1, and the bottom of the sliding shaft 308 is connected to the sliding rack 309, and the sliding rack 309 is provided with a one-way device 310. When the air flow of the circular filter cartridge 301 decreases, the internal air pressure increases, and at this time, the sliding plates 302 on both sides are subject to the increase in air pressure and then slide in a circle along the arc rod 303, thereby squeezing the arc spring 304. When the two sliding plates 302 slide, the lifting shaft 307 will be driven to move upward through the connection of the two stretching links 305, and then the lifting shaft 307 will drive the sliding shaft rod 308 to move upward, and the sliding rack 309 on the sliding shaft rod 308 will move upward accordingly, and the meshing of the toothed gears will drive the circular filter cartridge 301 to rotate, and the clean filter holes will be rotated to the top of the wellhead, thus re-forming the filtering structure of the filter screen.

[0034] In addition, the one-way device 310 includes a central shaft 3104, to which a connecting ring 3105 is fixedly connected, to which four ratchets 3102 are rotatably connected, to which a tension spring 3103 is connected, and the bottom of the tension spring 3103 is connected to the central shaft 3104, to which an outer tooth sleeve 3101 is clamped, and the outer surface of the outer tooth sleeve 3101 is provided with teeth, and the sliding rack 309 is engaged with the surface teeth of the outer tooth sleeve 3101, and the central shaft 3104 is fixed to the side of the circular filter cartridge 301, and a partition 311 is provided inside the shell 2, and the one-way device 310 is located in a sealed cavity formed between the partition 311 and the shell 2. As the elastic force of the arc spring 304 recovers, the two sliding plates 302 will be pushed back to their original positions, and the sliding rack 309 will also move up and reset, thereby driving the outer gear sleeve 310 to rotate in the opposite direction. The reverse rotation of the outer gear sleeve 3101 will not drive the rotation of the central shaft 3104, because the ratchet has unidirectional operation. In the forward gear state, the four ratchets 3102 will rotate to squeeze the tension spring 3103, thereby achieving the forward gear giving way.

[0035] In addition, the self-discharging component 4 includes a rotating shaft 401, a plurality of blades are arranged on the surface of the rotating shaft 401, the rotating shaft 401 is rotatably connected to the inside of the main body 1 through a connecting piece, a cam plate 402 is fixedly connected to the top of the rotating shaft 401, a contact plate 406 is abutted on the surface of the cam plate 402, a pull plate 403 is fixedly connected to the top of the contact plate 406, two guide rods 404 are fixedly connected to one side of the pull plate 403, and a compression spring 405 is sleeved on the surface of the guide rod 404. The rotation of the cam plate 402 will drive the lateral sliding of the contact plate 406, and then drive the lateral sliding of the pull plate 403, and then the action of the pull plate 403 will clean the flocculent impurities cleaned at the corners inside the shell 2 to the inside of the accumulation box 411.

[0036] It is worth noting that an upper sealing plate 408 is provided inside the shell 2, a push plate 407 is slidably connected to the shell 2, a push rod 409 is fixedly connected to the push plate 407, a contraction spring 410 is sleeved on the surface of the push rod 409, one end of the contraction spring 410 is connected to the shell 2, and the other end of the contraction spring 410 is connected to the upper sealing plate 408, and the shell 2 is provided with an accumulation box 411 below the push plate 407. Considering the sealing of the gas, the upper sealing plate 408 is provided, and when the pull plate 403 is flush with the upper sealing plate 408, the opening position below the upper sealing plate 408 will be closed to achieve the sealing of the shell 2 with the outside world, so that the gas will not leak, and the sealing of the discharge chute 412 by the push plate 407 in the initial state also achieves the overall sealing of the shell 2.

[0037] It is worth noting that one end of the push rod 409 passes through the housing 2 and is flush with the side of the upper sealing plate 408, and a discharge trough 412 is provided inside the accumulation box 411. Because only in the flush state, when the pull plate 403 slides, it can indirectly touch the push rod 409, and then synchronously drive the movement of the push plate 407, thereby exposing the discharge trough 412 below, and the discharge trough 412 is in an inclined state, so impurities or dirt will be automatically discharged along the inclined surface.

[0038] Working principle: first, when the wellhead device is used, the gas in the well passes through the equipment and is extracted upward from the bottom of the main body 1, and the mined gas passes through the circular filter cartridge 301 for double filtration. Because of the circular filter cartridge 301, the gas passes through the circular filter cartridge 301 and enters the interior of the circular filter cartridge 301, and then is discharged from the top of the circular filter cartridge 301, so a double-layer filter screening is directly formed. After that, it enters the upper pipeline inside the main body 1, and uses the multiple valves provided on the main body 1 to control the other limiting effects of the wellhead device during operation. The wellhead device, that is, the main body 1, is provided with multiple valves with different functions, such as production valves, wax cleaning valves, and casing valves, which are all existing technical means. When the gas is extracted for a long time, a certain amount of impurities will inevitably adhere to the bottom of the circular filter cartridge 301, resulting in a gradual decrease in the air intake. The decrease in the air intake will lead to an increase in the internal air pressure. The increase in air pressure will gradually drive the sliding plate 302 to slide on the arc-shaped round rod 303. For the sake of convenience, it can be regarded as that the filter holes under the circular filter cartridge 301 are all blocked, but in fact they are not all blocked. At this time, the gas cannot pass through the circular filter cartridge 301 during suction, resulting in an increase in the air pressure in the space. Therefore, the sliding plates 302 on both sides are affected by the increase in air pressure and then slide in a circle along the arc-shaped round rod 303, thereby squeezing the arc spring 304. When the two sliding plates 302 slide, the lifting shaft 307 will be driven to move upward through the connection of the two stretching connecting rods 305, and then the lifting shaft 307 will drive the sliding shaft rod 308 to move upward, and the sliding rack 309 on the sliding shaft rod 308 will move upward accordingly, and the meshing of the toothed gears will drive the rotation of the outer gear sleeve 3101, and the inner wall of the outer gear sleeve 3101 is provided with ratchets, so when the outer gear sleeve 3101 rotates, the central shaft 3104 on the connecting ring 3105 will be driven to rotate through the four ratchets 3102, and the rotation of the central shaft 3104 will drive the rotation of the circular filter cartridge 301, so at this time, the clean filter holes will rotate with the rotation of the circular filter cartridge 301 The filter element 301 is a kind of filter element with a plurality of grooves, and the grooves 310 of the outer sleeve 310 are connected to the filter element 311 of the outer sleeve 3101. The outer sleeve 3101 is a kind of filter element with a plurality of grooves, and the grooves 3102 ...Therefore, the principle of the overall operation process is that when the filter holes are gradually blocked or the ventilation volume is gradually reduced, the internal air pressure will gradually increase, which will push the two sliding plates 302 to slide, and then drive the circular filter cartridge 301 to rotate at a small angle through the connecting structure, and rotate the clean filter holes to the top of the wellhead to reform the filtering structure of the filter screen. When the ventilation volume gradually increases, the air pressure will decrease, and the sliding plate 302 will reset, waiting for the next filter hole to be blocked, thereby realizing the automatic filtration process of repeated rotation without the need for equipment shutdown or manual operation by maintenance personnel. When the sliding plate 302 is reset and slid, the surface of the circular filter cartridge 301 will be scraped and the impurities attached to the surface of the circular filter cartridge 301 will be cleaned. The cleaned impurity flocs will be deposited inside the shell 2. As the airflow flows from the well, it will drive the rotation of the blades, and then drive the rotation of the rotating shaft 401. Then the cam plate 402 will rotate with the rotation of the rotating shaft 401. Because the contact plate 406 is in contact with the cam plate 402 at this time, the rotation of the cam plate 402 will drive the lateral sliding of the contact plate 406, and then drive the lateral sliding of the pull plate 403. The pull plate 403 will gradually slide to the lower position of the upper sealing plate 408, and after contacting the sealing plate 408, it will contact the push rod 409 again in a synchronous state, and then slide again. , pushing the push rod 409 to move synchronously, and the movement of the push rod 409 will synchronously drive the push plate 407 connected to it to move, and then the upper opening position of the accumulation box 411 will be exposed, so the impurities will be pushed into the interior of the accumulation box 411 by the sliding of the pull plate 403. Considering the gas sealing, an upper sealing plate 408 is set. When the pull plate 403 is flush with the upper sealing plate 408, the opening position below the upper sealing plate 408 will be closed to achieve the sealing of the shell 2 with the outside world, so that the gas will not leak. After that, when the convex point position of the cam disk 402 gradually separates from the contact plate 406, it will be reset by the elastic force of the contraction spring 410 and the extrusion spring 405, which will gradually push the pull plate 403 and the push plate 407 to reset, waiting for the next rotation to discharge the material. When the pull plate 403 is reset, impurities may be pushed into the middle position of the shell 2. Because there is a circular pipe below, the impurities after cleaning will only exist in the four corner planes of the shell 2. When reset, some impurities will be pushed back into the middle of the circular pipe. As the airflow is sucked upward, the impurities in this part will be placed back on the surface of the circular filter cartridge 301. In this case, one can only wait for the next rotation and cleaning of the circular filter cartridge 301. However, the device can realize automatic operation without manual operation, so it is more convenient.

[0039] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A metal-sealed gas production wellhead device, characterized in that: include Subject (1); Housing (2); A filtering component (3) is used to perform circulating filtration on the gas in the wellhead; A self-draining component (4) for automatically discharging foreign particles attached to the filtering component (3); The filtering component (3) comprises a screening device and an indexing and rotating device; The screening device is used to filter gas impurities in the well; The indexing rotation device is used to control the indexing rotation of the internal screening device; The filtering component (3) is arranged inside the shell (2), and the self-draining component (4) is arranged inside the main body (1) and below the screening device.

2. A metal-sealed gas production wellhead device according to claim 1, characterized in that: The screening device comprises a circular filter cartridge (301), wherein the circular filter cartridge (301) is rotatably connected to the interior of a housing (2), a sliding plate (302) is slidably connected to the inner wall of the housing (2), and the bottom of the sliding plate (302) abuts against the circular filter cartridge (301).

3. A metal-sealed gas production wellhead device according to claim 2, characterized in that: A positioning plate (306) is fixedly connected inside the shell (2), and two arc-shaped round rods (303) are fixedly connected to the positioning plate (306). The two arc-shaped round rods (303) are fixed inside the shell (2) via connecting pieces, and an arc spring (304) is sleeved on the surface of the arc-shaped round rod (303), and the two ends of the arc spring (304) are respectively connected to the sliding plate (302) and the positioning plate (306).

4. A metal-sealed gas production wellhead device according to claim 3, characterized in that: The arc-shaped round rods (303) and the arc springs (304) are provided in two groups, and the two groups of arc-shaped round rods (303) and the arc springs (304) are symmetrically distributed about the center line of the circular filter cartridge (301).

5. A metal-sealed gas production wellhead device according to claim 4, characterized in that: The indexing rotation device comprises a stretching connecting rod (305), one end of which is rotatably connected to a sliding plate (302), and the other end of which is rotatably connected to a lifting shaft (307). A sliding shaft (308) is fixedly connected to the lifting shaft (307), and the sliding shaft (308) is slidably connected to a main body (1). The bottom of the sliding shaft (308) is connected to a sliding rack (309), and a one-way device (310) is provided on the sliding rack (309).

6. A metal-sealed gas production wellhead device according to claim 5, characterized in that: The one-way device (310) comprises a central shaft (3104), a connecting ring (3105) fixedly connected to the central shaft (3104), four ratchet clips (3102) rotatably connected to the connecting ring (3105), a tension spring (3103) connected to the ratchet clip (3102), the bottom of the tension spring (3103) being connected to the central shaft (3104), an outer tooth sleeve (3101) being clamped to the ratchet clip (3102), the outer surface of the outer tooth sleeve (3101) being provided with teeth, the sliding rack (309) being meshed with the surface teeth of the outer tooth sleeve (3101), the central shaft (3104) being fixed to the side of the circular filter cartridge (301), a partition (311) being provided inside the shell (2), and the one-way device (310) being located in a sealed cavity formed between the partition (311) and the shell (2).

7. The metal-sealed gas production wellhead device according to claim 1, characterized in that: The self-discharging component (4) comprises a rotating shaft (401), a surface of which is provided with a plurality of blades, the rotating shaft (401) being rotatably connected to the interior of the main body (1) via a connecting piece, a cam plate (402) being fixedly connected to the top of the rotating shaft (401), a surface of which is abutted against a contact plate (406), a pull plate (403) being fixedly connected to the top of the contact plate (406), two guide rods (404) being fixedly connected to one side of the pull plate (403), and a compression spring (405) being sleeved on the surface of the guide rod (404).

8. The metal-sealed gas production wellhead device according to claim 7, characterized in that: An upper sealing plate (408) is provided inside the shell (2), a push plate (407) is slidably connected to the shell (2), a push plate (407) is fixedly connected to the push plate (407), a contraction spring (410) is sleeved on the surface of the push plate (409), one end of the contraction spring (410) is connected to the shell (2), and the other end of the contraction spring (410) is connected to the upper sealing plate (408), and an accumulation box (411) is provided on the shell (2) below the push plate (407).

9. A metal-sealed gas production wellhead device according to claim 8, characterized in that: One end of the push rod (409) passes through the shell (2) and is flush with the side surface of the upper sealing plate (408), and a discharge chute (412) is provided inside the accumulation box (411).

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