CN217234451U - Check valve core and check valve - Google Patents

Abstract

The utility model discloses a check valve core and a check valve, which comprises a valve core body and a supporting cylinder, wherein the valve core body comprises a cylindrical fixed section and a duckbilled switch section, and the supporting cylinder comprises a cylindrical part and a wedge part; the switch section comprises an upper supporting part, a lower supporting part and two connecting parts which are respectively connected with the two sides of the upper supporting part and the lower supporting part; the upper supporting part is positioned at the upper side of the wedge-shaped part, the lower supporting part is positioned at the lower side of the wedge-shaped part, the supporting part and the lower supporting part are both connected with supporting plates, and the supporting plates and the wedge-shaped part act together to bear stronger non-return pressure, namely the back pressure capacity is strong; the two ends of the supporting plate are positioned between the two ends of the switch section, the supporting plate avoids end fixing, so that elastic resistance cannot be generated when the switch section is opened, and slurry from the upstream only needs to overcome the elastic force among the upper supporting part, the lower supporting part and the connecting part. The utility model discloses can adapt to shield structure construction demand, non return effectual, difficult jam, opening pressure is little, full latus rectum and wearability are good.

Description

Check valve core and check valve

Technical Field

The utility model relates to a thick liquid non return technical field especially indicates a non return case and check valve.

Background

(1) When the shield machine, in particular to a slurry shield, is in construction, slurry backflow or slag stone backflow of a pipeline can be caused due to the influence of slurry pressure change or pressure difference in the pipeline, and pipeline blockage or other liquid substance pollution is easily caused. The pipeline for the shield machine is required to be provided with a valve with a check device.

(2) There are many kinds of valves having a check function in the market. For example, swing check valves, ball float check valves, etc., but these valves are not full bore valves, and the mud flow or high velocity mud flow not only wears the valves severely, but also places strict requirements on the position and orientation of the check valves. The traditional check valve is arranged in the cutter head and can be automatically opened along with the rotation of the cutter head to play a role in non-return.

(3) As for the Chinese utility model patent with the publication number of CN 207999259U and the publication date of 2018.10.23, the utility model discloses a flexible non-return device, including the big end flange, big end flange and flange joint, flange joint is connected with the valve casing, valve casing and little end flange joint, big end flange and little end flange all with pipe connection, all be equipped with the through-diameter hole on big end flange and the little end flange, the through-diameter hole of big end flange and little end flange all communicates with the inner chamber of valve casing, the through-diameter hole department of big end flange is equipped with the flexible valve assembly that is located the inner chamber, the flexible valve assembly includes flat mouth rubber, the steel sheet that prebends, skeleton pipe lining and skeleton pipe, skeleton pipe inside lining is established in the through-diameter hole department of big end flange, the outside at skeleton pipe inside lining is established to the skeleton pipe, flat mouth rubber establishes in the outside of skeleton pipe, flat mouth rubber is embedded to have two upper and lower prebends steel sheet.

(4) Above-mentioned utility model provides a flexible non return device, although the rotation of blade disc does not influence its switching, but the case resistance of opening remains to be reduced, and whole valve assembly structure is complicated relatively, and weight is heavier, and the wearability that just supports a section of thick bamboo and case remains to improve.

(5) The duckbilled check valve in the industry has limited wear resistance and pressure bearing capacity, the structural design is difficult to adapt to the shield construction requirement, and the high pressure bearing and non-return effects are poor. In order to ensure the normal operation of the tunnel boring machine pipeline, in particular to the pipeline for the normal-pressure cutter head, a non-self-starting check valve core and a check valve with small opening resistance are urgently needed, and if the full-bore, high back pressure and high wear resistance can be realized, the effect of the non-self-starting check valve core and the check valve applied to the slurry pipeline of the slurry shield is optimal.

Disclosure of Invention

To not enough among the above-mentioned background art, the utility model provides a non-return valve core and check valve has solved the big technical problem of non-self-starting check valve opening resistance among the prior art.

The technical scheme of the application is as follows:

a check valve core comprises a valve core body and a supporting cylinder, wherein the valve core body comprises a cylindrical fixing section and a duckbilled opening and closing section, and the supporting cylinder comprises a cylindrical part and a wedge-shaped part; the fixing section is sleeved outside the cylindrical part, and the cylindrical part provides reliable support for the fixing section of the check valve core; the switch section comprises an upper supporting part, a lower supporting part and two connecting parts which are respectively connected with the two sides of the upper supporting part and the lower supporting part; when the fixed section does not have slurry towards the switch section, the upper supporting part and the lower supporting part are close to each other under the action of elastic force among the upper supporting part, the lower supporting part and the connecting part, so that the automatic closing of the switch section is realized; the upper supporting part is positioned at the upper side of the wedge-shaped part, the lower supporting part is positioned at the lower side of the wedge-shaped part, and the wedge-shaped part plays a role in positioning the upper supporting part and the lower supporting part, so that the switch section is prevented from being accidentally closed or accidentally opened when slurry pressure fluctuates, and meanwhile, the service life of the switch section is also ensured; the supporting part and the lower supporting part are both connected with a supporting plate, and the supporting plate and the wedge-shaped part act together to bear stronger non-return pressure, namely, the back pressure capability is strong; the front end and the rear end of the supporting plate are located between the front end and the rear end of the switch section, the supporting plate avoids end fixing, so that elastic resistance cannot be generated when the switch is opened, and slurry from the upstream only needs to overcome the elastic force among the upper supporting part, the lower supporting part and the connecting part, namely the switch is small in opening resistance.

Furthermore, the thickness of going up supporting part and lower support portion all is greater than the thickness of fixed section, makes to have higher elastic resistance between last supporting part, lower support portion and the connecting portion, avoids the unexpected opening of switch section.

Further, the limit between the fixed section and the switch section is marked as limit one, the limit between the cylindrical part and the wedge-shaped part is marked as limit two, and the axial position of the limit one is the same as that of the limit two. When the switch section is opened, the firmness of the fixed section can not be influenced, and when the fixed section is in a fixed state, the switch section can not be negatively acted.

Furthermore, the thickness of the connecting part is smaller than that of the upper supporting part and the lower supporting part, so that the overlarge opening resistance is avoided; the circumference direction of connecting portion is provided with the strengthening rib, avoids connecting portion structural strength to hang down excessively. The opening resistance is avoided too big when guaranteeing structural strength promptly.

Furthermore, each connecting portion is provided with three reinforcing ribs which are arranged at equal intervals, and two ends of each reinforcing rib are connected with the upper supporting portion and the lower supporting portion respectively, so that the structural strength of the connecting portions is further guaranteed, and the service life of the whole check valve core is further prolonged.

Further, one of the reinforcing ribs is disposed adjacent to the fixed section. Because the position of the switch section closest to the fixed section is a reciprocating turnover part, the reinforcing rib is arranged close to the fixed section, and the service life of the check valve core can be further prolonged.

Furthermore, the supporting plate connected with the upper supporting part is embedded in the upper supporting part, and the supporting plate connected with the lower supporting part is embedded in the lower supporting part. Inlay the setting with support panel in inside, can avoid causing the problem that support panel drops to take place along with non return valve core uses for a long time.

Furthermore, the outlines of the upper supporting part and the lower supporting part close to the fixed section are both arc-shaped, and the outlines departing from the fixed section are both linear; on the premise of ensuring non-self-starting, the starting convenience is further improved.

Furthermore, the surface of the valve core body is provided with the cord fabric layer, so that the connectivity between rubbers is enhanced, the falling of rubber materials is prevented, and the service life of the valve core is prolonged.

The utility model provides an use check valve of non return case, includes well barrel, well barrel one end is connected the upstream flange, and the other end is connected the low reaches flange, it links to each other with the upstream flange to support a section of thick bamboo, the case body is located between upstream flange and the low reaches flange, the canned paragraph passes through the clamping ring and links to each other with the upstream flange.

Furthermore, the upstream flange, the middle cylinder, the supporting cylinder, the pressure ring and the downstream flange are all of a revolving body structure. The design of full latus rectum, the runner is smooth-going, and the resistance is less, and the wearability is strong. The upstream flange, the downstream flange, the middle cylinder body, the supporting cylinder and the pressing ring are all of a revolving body structure, the material preparation and processing are both convenient, the cost is low, and the processing economy is good.

Furthermore, a mounting hole is formed in the upstream flange, the supporting cylinder is matched with the mounting hole in an inserted mode, and the outer wall of the supporting cylinder is welded with the inner wall of the upstream flange. The supporting cylinder is designed to be full in diameter, staggered platforms and welding seams do not exist inside the supporting cylinder, the whole service life is long, materials of the supporting cylinder are replaced under special conditions, and the wear resistance is enhanced conveniently.

Furthermore, the downstream end of the upstream flange is in plug-in fit with the inner cavity of the middle cylinder, the upstream end of the downstream flange is in plug-in fit with the inner cavity of the middle cylinder, and welding grooves are arranged between the butt-joint ends of the upstream flange and the middle cylinder and between the butt-joint ends of the downstream flange and the middle cylinder. The whole body adopts a welding form, so that the complexity of the traditional flange connection is avoided, the weight of the valve is favorably reduced, and the installation is convenient; the downstream flange is provided with a conical inner cavity for transition, so that slurry flows smoothly; the whole shell is columnar, and the attractiveness is better.

The utility model provides a check valve core and a check valve, the device is a non-self-opening valve, is not influenced by the installation environment, and the valve installed on a moving or rotating pipeline can not be opened by itself; the valve shell and the flange of the device are non-casting parts and have good tensile and torsional properties; the supporting cylinder and the valve core are designed in a V shape, and a supporting plate is embedded in the valve core, so that the valve core can bear stronger non-return pressure (back pressure capacity); the design of full latus rectum, the runner is smooth-going, and the resistance is less, and the wearability is strong. The upstream flange, the downstream flange, the middle cylinder body, the supporting cylinder and the pressing ring are all of a revolving body structure, so that the material preparation and processing are both convenient, the cost is low, and the processing economy is good; the whole body adopts a welding form, so that the complexity of the traditional flange connection is avoided, the weight of the valve is favorably reduced, and the installation is convenient; the transition of the conical inner cavity of the downstream flange ensures smooth slurry flow; the integral shell is columnar, so that the attractiveness is better; the supporting cylinder is designed in a full-bore way, no dislocation exists in the supporting cylinder, no welding line exists in the supporting cylinder, the service life of the whole supporting cylinder is long, and the material of the supporting cylinder is replaced under special conditions, so that the wear resistance is enhanced conveniently; the valve core is internally provided with a plate, so that the crushing resistance of the valve core is enhanced; the cord fabric is designed on the outer side of the valve core, so that the connectivity between rubbers is enhanced, the falling of rubber materials is prevented, and the service life of the valve core is prolonged; the device occupies small space, has reasonable production and manufacturing process, lower cost and good economic applicability.

Drawings

In order to illustrate the embodiments of the present invention more clearly, the drawings that are needed in the description of the embodiments will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present invention, and that other drawings can be obtained by those skilled in the art without inventive effort.

FIG. 1 is a cross-sectional view of a check valve cartridge of the present invention;

FIG. 2 is a cross-sectional view of the check valve of the present invention;

reference numbers in the figures:

1-downstream flange, 2-middle cylinder and 3-upstream flange;

4-support cylinder, 41-cylindrical part, 42-wedge part;

5-pressing ring and 6-bolt;

7-check valve core, 71-fixing section, 72-switch section, 721-upper supporting part, 722-lower supporting part, 73-supporting plate and 74-reinforcing rib.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without any creative effort belong to the protection scope of the present invention.

A check valve core, as shown in FIG. 1, comprises a valve core body and a supporting cylinder 4, wherein the valve core body comprises a cylindrical fixing section 71 and a duckbilled opening and closing section 72, the supporting cylinder 4 comprises a cylindrical part 41 and a wedge-shaped part 42, in this embodiment, the wedge-shaped part 42 preferably adopts a V-shaped structure, and the symmetry of the opening and closing section 72 in opening and closing is ensured; the fixing section 71 is sleeved outside the cylindrical part 41, and the cylindrical part 41 provides reliable support for the fixing section 71 of the check valve core.

The switch section 72 includes an upper support part 721, a lower support part 722, and two connecting parts respectively connected to two sides of the upper support part 721 and the lower support part 722; when the fixed section 71 does not have slurry towards the switch section 72, the upper supporting part 721 and the lower supporting part 722 are close to each other under the action of elastic force among the upper supporting part 721, the lower supporting part 722 and the connecting part, so that the automatic closing of the switch section 72 is realized; the upper supporting part 721 is positioned at the upper side of the wedge-shaped part 42, the lower supporting part 722 is positioned at the lower side of the wedge-shaped part 42, and the wedge-shaped part 42 plays a positioning role on the upper supporting part 721 and the lower supporting part 722, so that the switching section 72 is prevented from being accidentally closed or accidentally opened when the slurry pressure fluctuates, and meanwhile, the service life of the switching section 72 is also ensured;

the supporting portion 721 and the lower supporting portion 722 are both connected with a supporting plate 73, and the supporting plate 73 and the wedge portion 42 act together to bear stronger check pressure, i.e. the back pressure capability is strong; the front end and the rear end of the supporting plate 73 are positioned between the front end and the rear end of the switch section 72, the supporting plate 73 avoids end fixing, so that elastic resistance cannot be generated when the switch section is opened, and slurry from the upstream only needs to overcome the elastic force among the upper supporting part 721, the lower supporting part 722 and the connecting part, namely, the opening resistance is small.

On the basis of the above embodiment, as another preferred embodiment, the thicknesses of the upper supporting part 721 and the lower supporting part 722 are both greater than the thickness of the fixing section 71, so that the upper supporting part 721, the lower supporting part 722 and the connecting part have high elastic resistance, and the accidental opening of the switch section 72 is avoided.

In addition to the above-described embodiment, as another preferred embodiment, a limit between the fixed segment 71 and the switch segment 72 is referred to as a limit one, a limit between the cylindrical portion 41 and the wedge portion 42 is referred to as a limit two, and an axial position of the limit one is the same as an axial position of the limit two. The small opening pressure and the non-self-opening reliability are fully ensured, the firmness of the fixed section 71 is not influenced when the switch section is opened, and the switch section 72 is not influenced when the fixed section 71 is in a fixed state.

In addition to the above-described embodiments, as another preferred embodiment, the thickness of the connecting portion is smaller than the thickness of the upper support portion 721 or the lower support portion 722, so as to avoid an excessive opening resistance; the circumferential direction of connecting portion is provided with strengthening rib 74, avoids connecting portion structural strength to hang down excessively. The opening resistance is avoided too big when guaranteeing structural strength promptly.

On the basis of the above embodiment, as another preferred embodiment, each connecting portion is provided with three reinforcing ribs 74, the three reinforcing ribs 74 are arranged at equal intervals, and two ends of each reinforcing rib 74 are respectively connected with the upper supporting portion 721 and the lower supporting portion 722, so as to further ensure the structural strength of the connecting portion, and further prolong the service life of the whole check valve core.

On the basis of the above embodiment, as another preferred embodiment, one of the reinforcing ribs 74 is provided adjacent to the fixed segment 71. Because the position where the switch section 72 is closest to the fixed section 71 is a reciprocating turnover part, the reinforcing rib 74 is arranged close to the fixed section 71, and the service life of the check valve core can be further prolonged.

In addition to the above-described embodiments, as another preferred embodiment, the supporting plate 73 connected to the upper supporting portion 721 is embedded in the upper supporting portion 721, and the supporting plate 73 connected to the lower supporting portion 722 is embedded in the lower supporting portion 722. The support plate 73 is embedded inside, so that the problem that the support plate 73 falls off due to long-time use of the check valve core can be avoided.

On the basis of the above embodiment, as another preferred embodiment, the upper supporting portion 721 and the lower supporting portion 722 have an arc-shaped profile close to the fixed section 71 and a linear profile away from the fixed section 71; on the premise of ensuring non-self-starting, the starting convenience is further improved.

On the basis of the above embodiment, as another preferred embodiment, the surface of the valve core body is provided with the cord fabric layer, so that the connectivity between rubbers is enhanced, the falling off of rubber materials is prevented, and the service life of the valve core is prolonged.

A check valve using the check valve core is shown in figure 2 and comprises a middle cylinder body 2, one end of the middle cylinder body 2 is connected with an upstream flange 3, the other end of the middle cylinder body is connected with a downstream flange 1, a supporting cylinder 4 is connected with the upstream flange 3, the valve core body is positioned between the upstream flange 3 and the downstream flange 1, and a fixing section 71 is connected with the upstream flange 3 through a pressing ring 5.

In addition to the above embodiments, as another preferred embodiment, the upstream flange 3, the intermediate cylinder 2, the support cylinder 4, the pressure ring 5, and the downstream flange 1 are all of a solid-of-revolution structure. The design of full latus rectum, the runner is smooth-going, and the resistance is less, and the wearability is strong. The upstream flange, the downstream flange, the middle cylinder body, the supporting cylinder and the pressure ring are all of a revolving body structure, so that the material preparation and processing are convenient, the cost is low, and the processing economy is good.

On the basis of the above embodiment, as another preferred embodiment, the upstream flange 3 is provided with a mounting hole, the support cylinder 4 is in plug-in fit with the mounting hole, and the outer wall of the support cylinder 4 is welded with the inner wall of the upstream flange 3. The supporting cylinder is designed to be full in diameter, staggered platforms and welding seams do not exist inside the supporting cylinder, the whole service life is long, materials of the supporting cylinder are replaced under special conditions, and the wear resistance is enhanced conveniently.

On the basis of the above embodiment, as another preferred embodiment, the downstream end of the upstream flange 3 is in insertion fit with the inner cavity of the middle cylinder 2, the upstream end of the downstream flange 1 is in insertion fit with the inner cavity of the middle cylinder 2, and welding bevels are respectively arranged between the abutting ends of the upstream flange 3 and the middle cylinder 2 and between the abutting ends of the downstream flange 1 and the middle cylinder 2. The whole body adopts a welding form, so that the complexity of the traditional flange connection is avoided, the weight of the valve is favorably reduced, and the installation is convenient; the downstream flange is provided with a conical inner cavity for transition, so that slurry flows smoothly; the whole shell is columnar, and the attractiveness is better. Besides the welding form, the connection form of the circular flanges can also be adopted among the upstream flange 3, the middle cylinder body 2 and the downstream flange 1.

The preferred embodiment of the check valve is:

a check valve comprises an upstream flange 3, a downstream flange 1, a middle cylinder 2, a check valve core 7, a supporting cylinder 4, a compression ring 5, a bolt 6 and the like. The supporting cylinder is inserted on the upstream flange 3 and connected together by welding; the top end of the supporting cylinder 4 is V-shaped; the upstream flange 3 and the middle cylinder 2 are inserted and centered and are connected together by welding; the check valve core 7 is buckled on the supporting cylinder 4, the inner cavity of the check valve core 7 is V-shaped, and the check valve core 7 is made of rubber or other materials except rubber; a supporting plate 73 is arranged in the inclined position of the check valve core 7, and a cord fabric layer is designed on the outer side of the check valve core 7; the pressure ring 5 is sleeved on the check valve core 7 and is connected to the upstream flange 3 through a bolt 6; the downstream flange 1 and the middle cylinder 2 are inserted and centered and are connected together by welding, a tapered groove is designed on the downstream flange 1, and a threaded hole for connecting the flange and a threaded hole for mounting a screw hook are designed on the upstream flange and the downstream flange.

During assembly, the support cylinder 4 is firstly welded with the upstream flange 3 and machined, and then the upstream flange 3 and the middle cylinder body 2 are welded; combining a check valve core 7 and a pressure ring 5 together, connecting the check valve core 7 to the upstream flange 3 through a bolt, and fastening the bolt 6; and the downstream flange 1 and the middle cylinder 2 are inserted, centered and welded, and after the welding is finished, the welding seam is machined.

The two ends of the check valve of the embodiment are connected with the pipeline through the threaded fasteners, the device has directivity in use, and the valve core is in the flowing direction of slurry from large to small in a natural state. The device is in the closed state under natural state, no matter how install novel check valve, whether can not open automatically along with pipeline motion.

The slurry in the pipeline impacts the upstream end of the check valve, the check valve core 7 is opened, along with different flow rates and different impact forces, the flow area of the opened check valve core 7 is different, and the slurry smoothly passes through the device after the opening.

The slurry in the pipeline does not flow, no impact is generated on the check valve core 7, and the check valve core 7 is in a closed state under the action of the check valve core 7. If pressure slurry exists at the downstream side of the pipeline, the slurry pressure acts on the outer inclined surface of the check valve core 7, and an extrusion force is applied to the valve core, so that the valve core is closed more tightly, the pressure bearing effect is better, and the check effect is achieved.

The present invention is not exhaustive and is well known to those skilled in the art.

The foregoing shows and describes the basic principles and features of the present invention, together with the advantages thereof. The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (13)

1. The utility model provides a non-return valve core, includes case body and support section (4), the case body includes the switch section (72) of the fixed section (71) of tube-shape and duckbilled, support section (4) including tube-shape portion (41) and wedge portion (42), fixed section (71) cover is established outside tube-shape portion (41), switch section (72) include support portion (721), lower support portion (722) and connect two connecting portion in upper support portion (721) and lower support portion (722) both sides respectively, its characterized in that: the upper supporting part (721) is located on the upper side of the wedge-shaped part (42), the lower supporting part (722) is located on the lower side of the wedge-shaped part (42), the supporting part (721) and the lower supporting part (722) are both connected with a supporting plate (73), and the front end and the rear end of the supporting plate (73) are located between the front end and the rear end of the switch section (72).

2. The check valve cartridge of claim 1, wherein: the thicknesses of the upper support part (721) and the lower support part (722) are both larger than that of the fixed section (71).

3. The check valve cartridge according to claim 1 or 2, wherein: the limit between the fixed section (71) and the switch section (72) is marked as a limit I, the limit between the cylindrical part (41) and the wedge-shaped part (42) is marked as a limit II, and the axial position of the limit I is the same as that of the limit II.

4. The check valve cartridge of claim 3, wherein: the connecting part is provided with a reinforcing rib (74) in the circumferential direction.

5. The check valve cartridge of claim 4, wherein: every connecting portion are provided with three strengthening rib (74), and three strengthening rib (74) are the equidistant arrangement, and the both ends of strengthening rib (74) link to each other with upper support portion (721), lower support portion (722) respectively.

6. The check valve cartridge of claim 5, wherein: one of the reinforcing ribs (74) is disposed adjacent to the fixed section (71).

7. The check valve cartridge of any of claims 1-2, 4-6, wherein: the supporting plate (73) connected with the upper supporting part (721) is embedded in the upper supporting part (721), and the supporting plate (73) connected with the lower supporting part (722) is embedded in the lower supporting part (722).

8. The check valve cartridge of claim 7, wherein: the profiles of the upper supporting part (721) and the lower supporting part (722) close to the fixed section (71) are both arc-shaped, and the profiles of the upper supporting part and the lower supporting part far away from the fixed section (71) are both linear.

9. The check valve cartridge of any of claims 1-2, 4-6, 8, wherein: the surface of the valve core body is provided with a cord fabric layer.

10. A check valve, characterized by: the check valve core comprises the check valve core according to any one of claims 1 to 9, and further comprises a middle cylinder body (2), one end of the middle cylinder body (2) is connected with the upstream flange (3), the other end of the middle cylinder body is connected with the downstream flange (1), the supporting cylinder (4) is connected with the upstream flange (3), the valve core body is located between the upstream flange (3) and the downstream flange (1), and the fixing section (71) is connected with the upstream flange (3) through a pressing ring (5).

11. The check valve of claim 10, wherein: the upstream flange (3), the middle cylinder body (2), the supporting cylinder (4), the pressing ring (5) and the downstream flange (1) are all of a revolving body structure.

12. The check valve of claim 10 or 11, wherein: the mounting hole is formed in the upstream flange (3), the supporting cylinder (4) is matched with the mounting hole in an inserting mode, and the outer wall of the supporting cylinder (4) is welded with the inner wall of the upstream flange (3).

13. The check valve of claim 12, wherein: the downstream end of upper reaches flange (3) and the cooperation of pegging graft of the inner chamber of well barrel (2), the upstream end of lower reaches flange (1) and the cooperation of pegging graft of the inner chamber of well barrel (2), all be provided with the welding groove between the butt joint end of upper reaches flange (3) and well barrel (2), between the butt joint end of lower reaches flange (1) and well barrel (2).

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