CN120465874A - An anti-extrusion, recyclable and airtight sealing component - Google Patents

Abstract

The present invention discloses an anti-extrusion, recyclable, and airtight sealing assembly, which relates to the technical field of sealing assemblies and includes a central rubber tube, a rubber tube backing ring, a side rubber tube, and a spacer ring. The spacer ring, side rubber tube, and rubber tube backing ring are all symmetrical about the center of the central rubber tube. The end of the central rubber tube is connected to the spacer ring, which is connected to the side rubber tube, which is connected to the rubber tube backing ring. The rubber tube backing ring is connected to upper and lower guide rings via threads. The present invention uses the above-mentioned anti-extrusion, recyclable, and airtight sealing assembly, which has excellent anti-extrusion performance in high-temperature and high-pressure working environments, withstands bidirectional pressure differentials, has a good sealing effect, has low setting force, and is easy to recycle and remove.

Description

Anti-extrusion recoverable airtight sealing assembly

Technical Field

The invention relates to the technical field of sealing assemblies, in particular to an extrusion-resistant recyclable airtight sealing assembly.

Background

At present, along with the continuous development of oil and gas reservoirs, the gradual reduction of easy oil production gas resources and the gradual increase of global economy on oil and gas resource demands, well drilling activities are continuously shifted to high-risk and challenging environments such as complex geological areas, deep water, extreme high temperature and high pressure, and meanwhile, the proportion of high-temperature and high-pressure wells in oil fields is gradually increased, but the well conditions of the high-temperature and high-pressure wells are more complex, the adaptability requirements on all matched well completion products are higher, and the upgrading and updating requirements on conventional products in the market are more urgent and outstanding.

The oil and gas field has a great number of downhole process tools, such as oil field separate injection, layered transformation, fracturing, layered oil extraction, mechanical pipeline water shutoff and other operations. Wherein, the packer and the bridge plug are one of the tools which are indispensable to the oil and gas well drilling technology. The seal assembly is an important component of the packer, which is a core part in the packer and bridge plug. The performance of the sealing component is high and low, and plays a decisive role in upgrading packer and bridge plug products.

The sealing component is generally made of rubber materials, and is simply called a rubber cylinder due to a cylindrical structure. In the application environment of a high-temperature high-pressure well, the requirement on the sealing assembly is higher, but the application of the conventional sealing assembly in the high-temperature high-pressure environment is completely inapplicable, and the risk of seal losing under the high-temperature high-pressure resistant and pressure alternating load is particularly high. The strength of the rubber material at high temperature is extremely attenuated, the pressure generated by high pressure is greatly increased, and meanwhile, the influence of the tube string pulling pressure load and alternating load generated by the temperature, the piston, the expansion and the gravity effect of the environment is also realized, so that when the rubber material bears higher pressure difference in the high-temperature environment, the shoulder of the rubber barrel is more easily cracked, and the sealing of the rubber barrel is invalid. Aiming at the high-temperature and high-pressure sealing assembly used at present, on the basis of the conventional sealing assembly, springs are vulcanized at two ends of a rubber cylinder, metal bowls (metal materials easy to deform) are added at two ends of the rubber cylinder or a protection structure for vulcanizing the rubber cylinder and a metal net is added at two ends of the rubber cylinder, but under high pressure difference, the defect that the shoulder of the rubber cylinder cannot be cracked under the condition of protruding deformation is still overcome, so that the rubber cylinder is damaged, and simultaneously, the setting force is larger than that of the conventional rubber cylinder sealing assembly. Or a designer adds a plurality of layers of protective bowls and various patterns of metal of plastics, but the processing cost is high, and the protective bowls are complex and are not easy to recycle.

In addition, the working environment of the deep well and the ultra-deep well is not only high temperature and high pressure, but also gas corrosion and integral cutting and penetration of the sealing assembly, thereby causing the phenomena of air holes, peeling and cracks of rubber inside and outside the sealing element and greatly reducing the service life of the rubber. In a severe downhole operating environment, the strength properties of the rubber or polymeric material used as a seal decline dramatically with increasing temperature due to the combination of high temperature, high pressure and corrosive media. Under the environment of high temperature and high pressure corrosive gas, the sealing member material may lose its thermal stability and chemical resistance, and thus cannot be used. Conventional packing element seal assembly can not satisfy this demand, because packing element length is shorter to anti extrusion effect is poor, leads to sealing effect relatively poor under high temperature high pressure corrosive gas environment.

Disclosure of Invention

The invention aims to provide an extrusion-resistant recyclable airtight sealing component, which has the characteristics of excellent extrusion-resistant performance, bearing of bidirectional pressure difference, good sealing effect, low setting force and simplicity in recycling and taking out under a high-temperature and high-pressure working environment.

In order to achieve the aim, the invention provides an extrusion-resistant recyclable airtight sealing assembly which comprises a middle rubber cylinder, a rubber cylinder back ring, side rubber cylinders and a spacer ring, wherein the spacer ring, the side rubber cylinder and the rubber cylinder back ring are symmetrical with respect to the center of the middle rubber cylinder, the end part of the middle rubber cylinder is connected with the spacer ring, the spacer ring is connected with the side rubber cylinder, the side rubber cylinder is connected with the rubber cylinder back ring, and the rubber cylinder back ring is connected with an upper guide ring and a lower guide ring through threads.

Preferably, the angle between the upper guide ring and the outer wrist of the lower guide ring is 30-45 degrees, the rubber back ring is attached to the exogenous shape of the end part of the side rubber, and a gap of 4-9mm is reserved between the maximum outer diameter of the side rubber and the end face of the rubber back ring.

Preferably, the side rubber cylinder and the middle rubber cylinder are made of one of NBR, HNBR, AFLAS, VT ION and FFKM rubber materials, and the hardness of the middle rubber cylinder is lower than that of the side rubber cylinder.

Preferably, the outside of the middle rubber cylinder is provided with a horizontal oblique angle, the horizontal oblique angle is matched with one end of the spacing ring, one end of the spacing ring is provided with a lug inclined plane, the length of the lug is 4-7m, and the other end of the spacing ring is provided with an inclined plane which is connected with the side rubber cylinder.

Preferably, an inverted U-shaped empty groove is formed in the middle rubber cylinder, a retaining ring is arranged in the inverted U-shaped empty groove, and an O-ring groove and an O-ring are arranged in the retaining ring.

Preferably, the inside and outside of the edge of the rubber cylinder back ring are provided with round corners with the radius of 0.5-1, the rubber cylinder back ring is matched with the side rubber cylinder, the side rubber cylinder is connected with the spacer ring through an inclined plane, the inclined plane angle is 10 degrees to 20 degrees, and the joint of the spacer ring, the side rubber cylinder and the middle rubber cylinder adopts R round corner design.

Preferably, an O-shaped ring and an O-shaped ring back ring are arranged in the rubber cylinder back ring, and the O-shaped ring back ring is matched with the O-shaped ring.

Preferably, the inside of the side rubber cylinder is provided with an inverted U-shaped groove which is matched with the extrusion-preventing ring.

Preferably, the inside chamfer that is provided with of well packing element, well packing element is inside to be provided with semi-circular hollow, and semi-circular hollow is provided with two, and two semi-circular hollow all cooperate with the dabber.

Therefore, the extrusion-resistant recoverable airtight sealing component has the following beneficial effects:

(1) The present invention reduces the setting force structurally and can achieve excellent sealing effect.

(2) The back ring of the rubber cylinder adopts a bowl-shaped back ring structure, so that the annular space is enlarged, the shoulder damage of the high-pressure gas extrusion rubber cylinder is reduced, and better supporting capability is provided.

(3) The invention selects metal materials with certain ductility and strength, and can select high-compactness rubber with special medium resistance according to different well liquid environments and temperature conditions.

(4) The invention can meet the requirements of different working conditions, namely low-pressure or high-pressure working conditions, low-temperature and high-temperature working conditions, and the sleeve or naked eye can realize reliable air-tight sealing effect, and has stronger adaptability and practicability.

(5) The invention is suitable for various sleeve pound-level sizes, can prevent the rubber cylinder from being sealed in advance, has simple structure and high sealing performance, and has high efficiency and wide adaptability.

(6) The rubber cylinder sealing assembly is simple and effective in structure, short and small, convenient for tools to be put in, and capable of improving the applicability of products.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a schematic illustration of the construction of an embodiment of an extrusion-resistant recoverable hermetic seal assembly of the present invention;

FIG. 2 is a schematic illustration of a packing element setting for an extrusion resistant recoverable hermetic seal assembly of the present invention;

FIG. 3 is a schematic view of a second embodiment of an anti-extrusion recoverable hermetic seal assembly of the present invention;

FIG. 4 is a schematic view of a second packing element setting in accordance with an embodiment of the present invention;

FIG. 5 is a schematic view of a third embodiment of an extrusion-resistant recoverable hermetic seal assembly of the present invention;

FIG. 6 is a schematic view of a three-rubber sleeve setting in accordance with an embodiment of the present invention;

reference numerals

1. An upper guide ring, a rubber cylinder back ring, a side rubber cylinder, a partition ring, a middle rubber cylinder, a holding ring, a 7, an O-shaped ring, a mandrel, a 9, a lower guide ring, a 10, O-shaped ring back ring, an 11, an extrusion preventing ring, a 12, a semicircular concave space and a 13, a sleeve.

Detailed Description

The technical scheme of the invention is further described below through the attached drawings and the embodiments.

Unless defined otherwise, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like, as used herein, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

Examples

Referring to fig. 1-6, the invention provides an anti-extrusion recoverable airtight sealing assembly, which comprises a middle rubber cylinder 5, a rubber cylinder back ring 2, a side rubber cylinder 3 and a spacing ring 4, wherein the spacing ring 4, the side rubber cylinder 3 and the rubber cylinder back ring 2 are all symmetrical about the center of the middle rubber cylinder 5, the middle rubber cylinder 5 mainly plays an initial extrusion sealing role at low temperature and low pressure, the end part of the middle rubber cylinder 5 is connected with the spacing ring 4, and the two spacing rings 4 play a role in limiting deformation of the rubber cylinder and increase contact stress after initial setting. The spacing ring 4 is connected with the side rubber cylinder 3, and the side rubber cylinder 3 plays a role in ensuring strength and sealing mainly at high temperature and high pressure. The limit packing element 3 is connected with packing element back of body circle 2, and when two packing element back of body circles 2 can protect 3 of limit packing element to go into the well, seal assembly prevents the function of front seat seal owing to inside and outside bulge in advance, and the two-way annular force back that receives in the later stage supports limit packing element 3, avoids the shoulder to be frac and damage, and threaded connection takes simultaneously, does benefit to the recovery after the packing element deblocking, and packing element back of body circle 2 passes through threaded connection with upper and lower guide ring.

The angles of the upper guide ring 1 and the lower guide ring 9 and the outer wrist of the rubber back ring 2 are 30-45 degrees, the outer edge of the end part of the edge rubber 3 is tightly matched with the shape of the rubber back ring 2, and a gap between 4.0-9.0MM is needed between the end surface of the rubber back ring 2 and the maximum outer diameter of the rubber, so that the situation that the edge rubber 3 is cut before the edge rubber 3 is deformed due to the large bowl turning force of the rubber back ring 2 is prevented.

The middle rubber cylinder 5 and the side rubber cylinder 3 can select rubber materials according to different conditions such as temperature, bottom hole liquid, NBR, HNBR, AFLAS, VTION and the like, the airtight environment suggests to select rubber materials with high compactness, and gas is not easy to enter.

The sealing assembly comprises a middle rubber cylinder 5 and side rubber cylinders 3 which are cylindrical, wherein the two side rubber cylinders 3 and a spacing ring 4 are symmetrically arranged at two ends of the middle rubber cylinder 5, and meanwhile, the rubber cylinder back ring 2 is in threaded connection with and fixed with upper and lower parts of a product. After the product is put into the underground sleeve 13 during use, under the action of a set setting force, the upper guide ring and the lower guide ring are pressed to move towards the extrusion direction of the rubber barrel, so that the rubber barrel back ring 2, the side rubber barrel 3 and the middle rubber barrel 5 deform, an annular space between the sleeve 13 and the central shaft is tightly filled with compressed elastomer, and meanwhile, the back ring is supported to bear the later-stage high-temperature high-pressure and load change.

Example 1

The sealing assembly of the rubber cylinder can realize that the deformation form of the rubber cylinder is limited when the setting force is reduced, the contact stress between the sealing assembly and the sleeve mandrel is increased and improved, meanwhile, the effective sealing under the working condition of high temperature and high pressure is realized, and the recovery and the taking out of the rubber cylinder are ensured.

The rubber cylinder back ring 2 is made of copper or copper alloy or low alloy steel, the tensile strength of the metal material is more than 220MPa, and the elongation is more than 9%. The external or internal thread is optionally connected with the upper and lower guide rings by threads, which is beneficial to the unsealing and recycling of the later-stage rubber cylinder. The thickness of the outer bowl of the rubber cylinder back ring 2 is adjusted according to the strength and pressure-bearing requirements of selected materials, the thickness of the bowl can be kept the same or different, the thickness of a turning point is thin, the setting force is reduced, the thickness of the turning point is reduced, the reinforcing wrapping effect is selected to be thick with the end surface contact point of the upper guide ring 1, the angle between the vertical edge of the upper guide ring 1 and the outer bowl of the rubber cylinder back ring 2 is 30-45 degrees, the thickness, the length and the annular space size of the rubber cylinder 3 are properly adjusted, and the length of the outer wrapping corners is adjusted according to 13-pound different adjustment ranges of the sealing sleeve. The end face of the side rubber cylinder 3 is completely attached, the shoulder is prevented from being broken and damaged under the working condition of high temperature and high pressure, meanwhile, the side rubber cylinder is in threaded connection, when the packer can be unsealed, the tension force can directly act on the back ring 2 of the rubber cylinder, the limitation of the rubber cylinder is relieved, and the recovery is facilitated after the rubber cylinder is unsealed.

The edge rubber cylinder 3 is connected with the spacing ring 4 through an inclined plane, the edge rubber cylinder 3 is attached to the spacing ring 4 and is vertical to an angle of 10 degrees to 20 degrees, the setting force is reduced, meanwhile, the contact stress with the sleeve 13 and the mandrel 8, which is high-pressure in the later stage, is increased, and the better sealing effect of the edge rubber cylinder is provided. The spacer ring 4 is connected with the middle rubber cylinder 5 through a lug inclined plane, the lug is 4-7mm in length and is provided with an inclined plane, the sealing inside the side rubber cylinder 3 is enhanced, meanwhile, the middle rubber cylinder 5 has a certain limiting effect, the contact stress of the rubber cylinder after initial setting is increased, and an exhaust hole is suggested to be increased in the inside, so that the pressure difference between the inside and the outside of the rubber cylinder is balanced, and the risk of the falling into advance bulge is reduced. The spacer ring 4 may be made of low carbon steel, low alloy steel or stainless steel.

The hardness of the middle rubber cylinder 5 is different from that of the side rubber cylinder 3, the hardness of the side rubber cylinder 3 is generally high, the difference between the hardness and the hardness of the bottom of the middle rubber cylinder 5 is about 10-15 ℃, so that the middle rubber cylinder 5 is inflated firstly during setting, and the middle rubber cylinder 5 is inflated after the side rubber cylinder 3, and is mainly sealed with low strength. The outer part is provided with an oblique angle of 20-30 degrees to be attached to the inner oblique surface of the lug of the spacing ring 4, and the inner inverted U-shaped empty groove can reduce the setting force and increase the contact stress of the outer sleeve 13 of the middle rubber cylinder 5. The inside is in interference fit with the mandrel 8, and chamfering is arranged at the upper and lower parts of the inside, the length is 1.5-2.5mm, the length is 30-45 degrees with the horizontal, and assembly difficulty caused by interference fit during assembly is facilitated. The internal contact stress of the middle rubber cylinder 5 and the mandrel 8 is increased, and the low-temperature and reverse pressure bearing capacity of the whole rubber cylinder is provided.

The retaining ring 6 limits the deformation state of the middle rubber cylinder 5, reduces the setting force, ensures the repeated pressure bearing of the rubber cylinder when the rubber cylinder is subjected to low temperature and alternating bidirectional annular force by simultaneously contacting the middle rubber cylinder 5 with the sleeve 13 and the mandrel 8, and can adopt low carbon steel, low alloy steel or stainless steel or cast iron and other rigid materials for the retaining ring 6. The outside of the sealing device is matched with an inverted U-shaped empty groove in the middle rubber cylinder 5, an internal O-ring groove is matched with an O-ring 7 to work, the internal sealing capacity of the rubber cylinder and the mandrel 8 is enhanced, and the situation of losing caused by up-and-down movement of the mandrel 8 is prevented.

Example two

The rubber cylinder structure can limit the damage of the edge rubber cylinder 3 at the shoulder, increase and improve the setting range of the rubber cylinder and the sleeve 13, and realize the effective sealing under the working condition of high temperature and high pressure simultaneously due to the contact stress of the mandrel 8.

The inside and outside of the edge of the rubber cylinder back ring 2 are provided with round corners with the radius of 0.5-1, the rubber cylinder back ring 2 is matched with the side rubber cylinder 3, the side rubber cylinder 3 is connected with the spacing ring 4 through an inclined plane, the inclined plane angle is 10 degrees to 20 degrees, and the connection parts of the spacing ring 4, the side rubber cylinder 3 and the middle rubber cylinder 5 are all designed with R round corners.

An O-shaped ring 7 and an O-shaped ring back ring 10 are arranged in the rubber cylinder back ring 2, and the O-shaped ring back ring 10 is matched with the O-shaped ring 7.

The two rubber cylinder back rings 2 are easy to denature and have high strength. When the well is put into the well, the sealing structure of the protective edge rubber cylinder has the function of preventing the advanced setting due to the advanced bulge inside and outside, the setting range is increased by the turnover deformation during setting, the single-side annular space of the back ring can be 8-12mm, and the protective edge rubber cylinder 3 is supported after the later two-way pressure difference, so that the shoulder is prevented from being broken and damaged. The thickness of the outer bowl of the rubber back ring 2 is adjusted according to the strength and pressure-bearing requirements of selected materials, the angle between the vertical side of the upper guide ring 1 and the outer bowl of the rubber back ring 2 is 30-45 degrees, the outer wrapping corner length is properly adjusted according to the thickness and the length of the side rubber 3 and the annular space, and the outer wrapping corner length is adjusted according to the different adjustment ranges of 13 pounds of the sealing sleeve and the naked eye buttonhole rate. Meanwhile, the inside and outside of the edge of the bowl of the rubber back ring 2 are required to be rounded by R0.5-1, so that the situation that sealing is invalid due to the fact that the rubber cylinder 3 is cut by a sharp corner when later pressure bearing occurs is avoided.

The joint of the side rubber cylinder 3 and the spacer ring 4 is 10-20 degrees vertical, the setting force is reduced, and meanwhile, the contact stress with the sleeve 13 and the mandrel 8 which are high-pressure in the later stage is increased, so that the side rubber cylinder can be better sealed. The spacer ring 4 may be made of low carbon steel, low alloy steel or stainless steel. The angle of the first section of inclined surface is attached to the edge rubber cylinder 3, the sealing inside the edge rubber cylinder 3 is enhanced, meanwhile, the middle rubber cylinder 5 has a certain limiting effect, the contact stress of the rubber cylinder after initial setting is increased, and the contact part between the outer edge of the spacer ring 4 and the rubber cylinder adopts R fillet design.

The hardness of the middle rubber cylinder 5 is different from that of the side rubber cylinder 3, the hardness of the side rubber cylinder 3 is generally high, the hardness of the middle rubber cylinder 5 is high, the difference is about 10-15 ℃, the middle rubber cylinder 5 is inflated firstly during setting, the side rubber cylinder 3 is inflated later, and the middle rubber cylinder 5 is mainly sealed with low strength. The inside is in interference fit with the mandrel 8, and meanwhile, the inside is provided with chamfers with the length of 1.5-2.5mm and the level of 30-45 degrees up and down, so that the assembly is convenient due to difficult assembly caused by interference fit during assembly. The internal contact stress of the middle rubber cylinder 5 and the mandrel 8 is increased, and the low-temperature and reverse pressure bearing capacity of the whole rubber cylinder is provided.

The O-shaped ring 7 and the O-shaped ring back ring 10 are arranged in the rubber cylinder back ring 2, so that the internal sealing capability of the rubber cylinder and the mandrel 8 is enhanced, the situation of losing caused by up-and-down movement of the mandrel 8 is prevented, and the O-shaped ring back ring 10 mainly plays a role in supporting the O-shaped ring 7 at high temperature and high pressure.

Example III

The rubber cylinder assembly adopts a structure of a three-section rubber cylinder back-adding ring and a spacing ring 4, the rubber cylinder structure can limit the damage of the rubber cylinder 3 at the shoulder, the setting range of the rubber cylinder and the sleeve 13 is increased and improved, the contact stress of the mandrel 8 is increased, and meanwhile, the extrusion-resistant effective sealing under the working condition of a high-temperature high-pressure gas well is realized.

The inside of the side rubber cylinder 3 is provided with an inverted U-shaped groove which is matched with the extrusion preventing ring 11.

The inside chamfer that is provided with of well packing element 5 is provided with semi-circular hollow 12 in the well packing element, and semi-circular hollow 12 is provided with two, and two semi-circular hollow 12 all cooperate with dabber 8.

The inside and outside edge of the bowl of the rubber cylinder back ring 2 need to be rounded by R0.5-1, so that the situation that sealing is invalid due to the fact that the rubber cylinder is cut by a sharp corner when later-stage pressure bearing occurs is avoided.

The extrusion-preventing ring 11 is characterized in that according to the difference of temperature environments, PTFE and PEEK can be used, the extrusion-preventing ring 11 and the edge rubber cylinder 3 work cooperatively, the internal sealing capacity of the rubber cylinder and the mandrel 8 is enhanced, and the situation of losing caused by up-and-down movement of the mandrel 8 is prevented.

The joint of the side rubber cylinder 3 and the spacer ring 4 is 10-20 degrees vertical, so that the setting force is reduced, and meanwhile, the contact stress between the sleeve 13 and the mandrel 8 which bear high pressure in the later stage is increased, so that the side rubber cylinder 3 has a better sealing effect. The inside of the side rubber cylinder 3 is provided with an inverted U-shaped groove which is matched with the extrusion-proof ring 11, so that the setting force is reduced, and meanwhile, the contact stress between the side rubber cylinder 3 and the mandrel 8 during the later high pressure bearing is increased, and the situation of losing caused by the up-and-down movement of the mandrel 8 is prevented.

The spacer ring 4 may be made of low carbon steel, low alloy steel or stainless steel. The angle of the first section of inclined surface is attached to the edge rubber cylinder 3, the sealing inside the edge rubber cylinder 3 is enhanced, meanwhile, the middle rubber cylinder 5 has a certain limiting effect, the contact stress of the rubber cylinder after initial setting is increased, and the contact part between the outer edge of the spacer ring 4 and the rubber cylinder adopts R fillet design.

The semicircular hollow 12 in the middle rubber cylinder 5 can reduce the setting force. The inside is in interference fit with the mandrel 8, and meanwhile, the inside is provided with chamfers with the length of 1.5-2.5mm and the level of 30-45 degrees up and down, so that the assembly is convenient, and the assembly is difficult due to interference fit. The internal contact stress of the middle rubber cylinder 5 and the mandrel 8 is increased, and the low-temperature and reverse pressure bearing capacity of the whole rubber cylinder is provided.

The invention adopts the anti-extrusion recoverable airtight sealing component, structurally reduces the setting force and can realize excellent sealing effect, the rubber cylinder back ring adopts a bowl-shaped back ring structure, increases annulus, reduces the shoulder damage of the high-pressure gas extrusion rubber cylinder, provides better supporting capability, selects metal materials with certain ductility and strength, can select high-density rubber resistant to special media according to different well liquid environments and temperature conditions, can adapt to different working condition requirements, can realize reliable airtight sealing effect no matter low-pressure or high-pressure, low-temperature and high-temperature working conditions, and has stronger adaptability and practicability.

It should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted by the same, and the modified or substituted technical solution may not deviate from the spirit and scope of the technical solution of the present invention.

Claims (9)

1. The extrusion-resistant recoverable airtight sealing assembly is characterized by comprising a middle rubber cylinder, a rubber cylinder back ring, an edge rubber cylinder and a spacer ring, wherein the spacer ring, the edge rubber cylinder and the rubber cylinder back ring are symmetrical relative to the center of the middle rubber cylinder, the end part of the middle rubber cylinder is connected with the spacer ring, the spacer ring is connected with the edge rubber cylinder, the edge rubber cylinder is connected with the rubber cylinder back ring, and the rubber cylinder back ring is connected with an upper guide ring and a lower guide ring through threads.

2. The extrusion-resistant recoverable airtight sealing assembly of claim 1, wherein the angle between the upper guide ring and the lower guide ring and the outer wrist of the rubber back ring is 30-45 degrees, the rubber back ring is attached to the exogenous shape of the end part of the side rubber, and a gap of 4-9mm is reserved between the maximum outer diameter of the side rubber and the end face of the rubber back ring.

3. The extrusion-resistant recyclable airtight seal assembly as set forth in claim 2, wherein the side rubber and the middle rubber are made of one of NBR, HNBR, AFLAS, VTION and FFKM rubber materials, and the hardness of the middle rubber is lower than that of the side rubber.

4. The extrusion-resistant recoverable airtight sealing assembly of claim 3, wherein a horizontal oblique angle is arranged outside the middle rubber cylinder and is matched with one end of a spacing ring, one end of the spacing ring is provided with a lug inclined plane, the length of the lug is 4-7m, and the other end of the spacing ring is provided with an inclined plane connected with the side rubber cylinder.

5. The extrusion-resistant recoverable airtight sealing assembly of claim 4, wherein the inner part of the middle rubber cylinder is provided with an inverted U-shaped hollow groove, a retaining ring is arranged in the inverted U-shaped hollow groove, and an O-ring groove and an O-ring are arranged in the retaining ring.

6. The extrusion-resistant recoverable airtight sealing assembly according to claim 3, wherein the inner and outer edges of the back ring of the rubber cylinder are provided with round corners with the radius of 0.5-1, the back ring of the rubber cylinder is matched with the side rubber cylinder, the side rubber cylinder is connected with the partition ring through an inclined plane, the inclined plane angle is 10-20 degrees, and the connection parts of the partition ring, the side rubber cylinder and the middle rubber cylinder adopt R round corner design.

7. The extrusion-resistant recyclable airtight seal assembly as set forth in claim 6, wherein the rubber back ring is provided with an O-ring and an O-ring back ring, the O-ring back ring being mated with the O-ring.

8. The extrusion-resistant recyclable airtight seal assembly as set forth in claim 6, wherein the side packing elements are internally provided with inverted U-shaped grooves which are engaged with the extrusion-resistant rings.

9. The extrusion-resistant recoverable airtight sealing assembly of claim 8, wherein a chamfer is arranged in the middle rubber cylinder, semicircular concave spaces are arranged in the middle rubber cylinder, two semicircular concave spaces are arranged, and the two semicircular concave spaces are matched with the mandrel.