CN220134620U

CN220134620U - Ultralow Wen Long type valve with quick-change core-pulling structure

Info

Publication number: CN220134620U
Application number: CN202321073544.1U
Authority: CN
Inventors: 程路; 戚斌; 张宏
Original assignee: Xuzhou Arca Control Valve Co ltd
Current assignee: Xuzhou Arca Control Valve Co ltd
Priority date: 2023-05-08
Filing date: 2023-05-08
Publication date: 2023-12-05
Anticipated expiration: 2033-05-08

Abstract

The utility model discloses an ultralow Wen Long type valve with a quick-change core-pulling structure, which comprises a valve body, a valve cage, a guide sleeve, an extension tube assembly and a valve core and valve rod assembly, wherein the valve body is provided with a valve rod; one end of the valve body is provided with at least one medium inlet, and the other end of the valve body is provided with at least one medium outlet; the valve cage is arranged in the internal channel of the valve body, and is provided with at least one window for throttling the low-temperature fluid flowing in from the medium inlet; the guide sleeve is arranged at the upper end of the inlet of the internal channel of the valve body; the bottom of the extension tube component is connected with the guide sleeve, and the top of the extension tube component is connected with the valve cover; the valve core valve rod assembly is formed by integrally connecting a valve core and a valve rod, the valve rod is inserted into a valve cover, the extension tube assembly and a guide sleeve, the valve core is positioned in a valve cage, the flow cross section of a window in the valve cage is changed by moving the valve core up and down, the functions of regulating fluid flow and controlling pressure are realized, and the valve core valve rod assembly can be directly pulled out and replaced under the condition that the valve body and the extension tube assembly are not required to be disassembled.

Description

Ultralow Wen Long type valve with quick-change core-pulling structure

Technical Field

The utility model relates to the technical field of fluid control, in particular to an ultralow Wen Long valve with a quick-change core-pulling structure, which is used for meeting the requirements of mediums such as liquefied natural gas, liquefied air, liquid oxygen, liquid nitrogen and the like under the working condition of ultralow temperature (-196 ℃ to-100 ℃), and is suitable for low-temperature process automation control occasions such as petrochemical ethylene, liquefied air, LNG liquefied natural gas, liquefied petroleum and the like.

Background

The traditional ultra-low Wen Long valve product mainly comprises valve body, low-temperature lengthened valve cover, valve rod, valve core, valve cage, filler, gasket and other parts. The valve body one end is equipped with the import, and the other end is equipped with the export, and the case utilizes the cage direction, can reciprocate straight line at the cage internal surface, and the cage is opened all around has the window of different shapes to according to the size requirement of circulation ability, the window of cage can be three, four, six or a plurality of. When the valve core moves up and down linearly, the effective area of a window on the valve cage can be changed, so that the flow and the pressure of the low-temperature medium can be regulated and controlled. The main drawbacks of such a cage valve are: the valve core, the valve rod and other parts are complicated to detach and replace, and are not beneficial to on-line overhaul and maintenance. Particularly, when the valve body of the cage valve is connected with a pipeline in a welding mode and is arranged in the cold box, as the valve body and the lengthened valve cover part are not easy to detach, parts such as a damaged valve core, a damaged valve rod and the like are difficult to be smoothly and rapidly extracted and replaced, inconvenience and blockage are brought to normal field overhaul and maintenance work, and related requirements of related automation control enterprises such as liquefied air, liquefied natural gas and the like on online overhaul and maintenance of the ultralow temperature cage valve are difficult to be met.

Disclosure of Invention

In order to solve and overcome the technical defects that the traditional ultralow Wen Long type valve product is not beneficial to on-line maintenance and the like, the utility model provides a cage type valve with a quick-change core-pulling structure, which can meet the use of working condition mediums such as liquefied natural gas, liquefied air, liquid oxygen, liquid nitrogen and the like under the working condition of ultralow temperature (-196 ℃ to-100 ℃), so as to meet the actual requirements of related enterprises such as liquefied air, liquefied natural gas and the like on the aspects of on-site maintenance and the like of the ultralow Wen Long type valve, and expand the application range of the ultralow Wen Long type valve product.

The utility model is realized according to the following technical scheme:

an ultra-low Wen Long valve with quick change core-pulling structure, comprising:

one end of the valve body is provided with at least one medium inlet, and the other end of the valve body is provided with at least one medium outlet;

the valve cage is arranged in the internal channel of the valve body, is provided with at least one window and throttles low-temperature fluid flowing in from the medium inlet;

the guide sleeve is arranged at the upper end of the inlet of the internal channel of the valve body;

the bottom of the extension tube assembly is connected with the guide sleeve, and the top of the extension tube assembly is connected with the valve cover;

the valve core valve rod assembly is formed by integrally connecting a valve core and a valve rod, the valve rod is inserted in the valve cover, the extension tube assembly and the guide sleeve, the top end of the valve rod is used for being matched and connected with various straight stroke actuating mechanisms, the valve core is positioned in the valve cage, the flow cross section of a window in the valve cage is changed by moving the valve core up and down, the functions of regulating fluid flow and controlling pressure are realized, and the valve core valve rod assembly can be directly pulled out and replaced under the condition that the valve body and the extension tube assembly are not required to be disassembled.

In some embodiments, the valve body is provided with a medium inlet and a medium outlet, and the internal channel in the valve body has an S-shaped streamline structure.

In some embodiments, the valve cage is integrally of a cylindrical structure, and is screwed into and fixed in the valve body in a threaded connection manner; four windows are evenly spaced on the annular peripheral surface of the valve cage.

In some embodiments, a circle of 60-degree sealing line is arranged at the inner side wall of the lower part of the valve cage and the outer side wall of the bottom of the valve core, and the 60-degree sealing line is subjected to surfacing cemented carbide and then cryogenic treatment.

In some embodiments, the extension tube assembly adopts a long-neck extension tube structure and consists of an extension tube and a connecting disc; the connecting disc is welded at the upper part of the extension tube and is used for connecting and assembling a corresponding heat-insulation sealing sleeve.

In some embodiments, a toothed gasket is used to seal between the elongate tube assembly and the valve cover.

In some embodiments, the flange structure at the top of the extension tube assembly is uniformly provided with a plurality of threaded holes at intervals, and the flange structure at the bottom of the valve cover is provided with a plurality of through holes coaxial with the threaded holes; the screw bolt penetrates through the through hole and then is screwed in the threaded hole, the nut is screwed on the screw bolt positioned on the outer side of the flange structure of the extension tube component, and the extension tube component and the valve cover are fastened together by screwing the nut.

In some embodiments, a packing assembly is used to seal between the inner wall of the valve cover and the valve stem; the bottom of the packing assembly is limited to axially move through a step in the valve cover, and a packing gland, a disc spring and a packing gland nut are sequentially arranged at the top of the packing assembly from bottom to top and are fixed on the valve cover through the packing gland nut to compress and fix the packing assembly.

In some embodiments, a low leakage seal is mounted between the opposed peripheral surfaces of the spool and the guide sleeve.

In some embodiments, the guide sleeve is welded to the valve body; the lower end of the extension tube component is connected with the guide sleeve in a welding mode.

The utility model has the beneficial effects that:

the utility model can effectively reduce heat transfer, eliminate structural deformation and abnormal pressure rise of medium caused by temperature change, and ensure heat insulation performance and cooling performance of the valve. Meanwhile, the quick-change core-pulling type structure is beneficial to on-line overhaul and maintenance, the maintenance procedure and the process are simplified, the equipment parking time is reduced, the operation requirements of various low-temperature processes are met, the valve is ensured to reliably work under the ultralow-temperature working condition, the phenomenon of environmental pollution caused by ultralow-temperature medium leakage is prevented, the whole working life cycle of the valve is prolonged, and the application range of the ultralow Wen Long valve product is widened.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. It is evident that the drawings in the following description are only examples, from which other drawings can be obtained by a person skilled in the art without the inventive effort.

In the drawings:

FIG. 1 is a cross-sectional view of an ultra-low Wen Long valve with quick change core-pulling structure in accordance with the present utility model;

FIG. 2 is a cross-sectional view of the valve body of the present utility model (a is a front view, b is a side view, and c is a top view);

FIG. 3 is a schematic view of an elongate tube assembly of the present utility model (a is a front cross-sectional view and b is a top view);

FIG. 4 is a schematic view of a valve cover according to the present utility model (a is a front cross-sectional view, b is a top view);

FIG. 5 is a schematic view of a cage of the present utility model (a being a front cross-sectional view and b being a top view);

FIG. 6 is a cross-sectional view of a guide sleeve of the present utility model;

FIG. 7 is a cross-sectional view of a valve cartridge and stem assembly of the present utility model;

FIG. 8 is a schematic view of a low leakage seal ring of the present utility model.

The attached drawings are identified: valve body 1, valve cage 2, low leakage sealing washer 3, uide bushing 4, case valve rod subassembly 5, extension tube subassembly 6, profile of tooth gasket 7, valve gap 8, double-screw bolt nut subassembly 9, packing subassembly 10, round nut 11, gland 12, dish spring 13, gland nut 14, case 51, valve rod 52, connection pad 61, extension tube 62.

It should be noted that these drawings and the written description are not intended to limit the scope of the inventive concept in any way, but to illustrate the inventive concept to those skilled in the art by referring to the specific embodiments.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions in the embodiments will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model, and the following embodiments are used to illustrate the present utility model, but are not intended to limit the scope of the present utility model.

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 1, an ultra-low Wen Long type valve with a quick-change core-pulling structure mainly comprises a valve body 1, a valve cage 2, a low-leakage sealing ring 3, a guide sleeve 4, a valve core and valve rod assembly 5, an extension tube assembly 6, a valve cover 8, a packing assembly 10, a round nut 11, a packing gland 12, a disc spring 13, a packing gland nut 14, a corresponding tooth-shaped gasket 7, a stud, a nut 9 and other parts.

The utility model is designed based on the principles of standardization, universality and interchangeability, and adopts methods of software selection analysis, three-dimensional software simulation analysis, flow characteristic analysis and the like to precisely simulate and design the appearance, structure and size of main parts such as a valve body 1 (see fig. 2), an extension tube assembly 6 (see fig. 3), a valve cover 8 (see fig. 4), a valve cage 2 (see fig. 5), a guide sleeve 4 (see fig. 6), a valve core and valve rod assembly 5 (see fig. 7) and the like.

In order to ensure the impact toughness, relative elongation, wear resistance, corrosion resistance and other performances of important parts such as the valve body 1, the valve cage 2, the guide sleeve 4, the valve core valve rod assembly 5, the extension tube assembly 6, the valve cover 8 and the like at low temperature, austenitic stainless steel materials are selected and subjected to proper heat treatment. The 60-degree sealing lines on the valve core and the valve cage are all required to be welded with hard alloy in a surfacing mode, and then deep cooling treatment is carried out after welding. And simultaneously, before finish machining, all parts are subjected to cryogenic treatment.

The valve body 1, the valve cage 2, the low leakage seal ring 3, the guide sleeve 4, the valve core and valve rod assembly 5, the extension tube assembly 6, the valve cover 8 and the packing assembly 10 are further described below.

As shown in fig. 1 and 2, one end of the valve body 1 is provided with a medium inlet, the other end is provided with a medium outlet, and the channel of the medium outlet is in an S streamline shape. The two ends of the valve body are designed and manufactured into butt welding grooves according to the national industry standard of GB/T12224 general requirement for steel valves, so that the valve body can be smoothly welded with a pipeline on site. The low-temperature fluid can enter from the medium inlet end of the valve body 1, pass through a window on the side surface of the valve cage 2, throttle, change the direction and flow out from the medium outlet end of the valve body 1.

As shown in fig. 1 and 6, the guide bush 4 is welded to the valve body 1.

As shown in fig. 1 and 3, the extension tube assembly 6 is composed of an extension tube 62 and a connecting disc 61, and the connecting disc 61 is sleeved on a proper position of the extension tube 62 by adopting a long neck type structural design and is firmly welded. The lower end of the extension tube assembly 6 is connected with the guide sleeve 4 by welding, and the upper end is connected with the valve cover 8 by a stud nut assembly 9, namely a plurality of threaded holes are uniformly and alternately arranged on the flange structure at the top of the extension tube 62, and a plurality of through holes coaxial with the threaded holes are arranged on the flange structure at the bottom of the valve cover 8; the stud is threaded through the through hole and then screwed into the threaded hole, and the nut is screwed onto the stud located outside the flange structure of the extension tube 62, thereby fastening the extension tube assembly and the valve cap 8 together by screwing the nut. The extension tube assembly 6 and the valve cover 8 are sealed by a tooth-shaped gasket 7.

It should be noted that the long tube assembly 6 adopts a long neck structure, so as to reduce heat transferred into the valve from the outside, and ensure that the temperature of the stuffing box part is above 0 ℃, so that the stuffing can work normally, and prevent the valve rod at the stuffing box part and parts at the upper part of the valve cover from frosting or freezing due to supercooling of the stuffing part. Meanwhile, the heat transfer can be effectively reduced, the heat insulation performance and the cooling performance of the valve are ensured, and the structural deformation and the abnormal medium pressure rise phenomenon caused by temperature change are eliminated.

Use of the connection pad on the elongate tube assembly 6: when the valve is to be installed in a cold box, the connecting disc 61 can be used for connecting and assembling corresponding heat-insulating sealing sleeves so as to ensure the heat-insulating performance and the cooling performance of the valve.

As shown in fig. 1 and 5, the cage 2 is located between the inlet and the outlet of the valve body 1, and screwed into and fixed in the valve body 1 by a threaded connection. Four windows are respectively arranged around the side face of the valve cage 2, the shapes, the sizes and the positions of the four windows are very important, and the influence on the Cv value of the valve and the accuracy of the flow characteristic curve is very great, so that the shapes, the sizes and the positions of the four windows are precisely simulated and specially designed by adopting Solidworks three-dimensional software during design, and the technical parameters of equal percentage of flow characteristics, cv150 of maximum flow coefficient and 40mm of maximum travel are met, and meanwhile, the accuracy of the flow characteristic curve is guaranteed to be high, and the regulation performance is good. In addition, a 60-degree sealing line matched with the valve core 51 is processed on the valve cage 2, and the 60-degree sealing line adopts a hardening treatment mode of overlaying stellite.

As shown in fig. 1 and 7, the valve core and valve rod assembly 5 is formed by integrally connecting a valve core 51 and a valve rod 52, the valve rod 52 is inserted into the valve cover 8, the extension tube assembly 6 and the guide sleeve 4, the valve core 51 is positioned in the valve cage 2 and the guide sleeve 4, a 60-degree sealing line is processed on the valve core 51, and the 60-degree sealing line adopts a overlaying stellite hardening treatment mode.

As shown in fig. 1 and 8, the low leakage seal ring 3 is mounted in a seal groove on the valve element 51 of the valve element stem assembly 5.

As shown in fig. 1 and 7, the valve-core stem assembly 5 is guided by the cage 2, the inner surface of the guide bush 4, and the outer surface of the low-leakage seal ring 3, and the stem 52 is guided by the packing assembly 10. The valve core and valve rod assembly 5 can linearly reciprocate up and down on the inner surfaces of the valve cage 2, the guide sleeve 4 and the packing assembly 10. When the valve core 51 moves up and down, the flow cross-sectional areas of four windows in the valve cage 2 can be changed, and the functions of regulating the fluid flow and controlling the pressure are realized.

It should be noted that, the valve core and valve rod assembly 5 adopts a quick-change core-pulling structure, when the valve body 1 is connected with a pipeline in a welding manner and is installed in a cold box, the valve body 1 and the extension tube assembly 6 do not need to be disassembled, and the parts such as the valve core 51, the valve rod 52 and the like can be conveniently and rapidly pulled out and replaced, so that the maintenance procedure and the process are simplified, the equipment parking time is reduced, and the on-site overhaul and maintenance work is simple and feasible. The design structure is particularly suitable for the ultralow temperature working condition occasion where the valve needs to be installed in the cold box.

With continued reference to fig. 1, the packing assembly 10 is used to seal between the valve core and valve rod assembly 5 and the valve cover 8, and the uppermost end of the valve rod 52 can be coupled with various straight travel actuators. The packing assembly 10 takes the form of a double layer PTFE packing seal.

As shown in fig. 1 and 4, the lower end of the valve cover 8 is connected with the extension tube assembly 6 through a stud nut assembly 9, and is sealed with the extension tube assembly 6 by a tooth-shaped gasket 7. The packing assembly 10, the packing gland 12, the disc spring 13, the packing gland nut 14 and other parts are all arranged in the valve cover 8. In addition, the upper end of the valve cover 8 is provided with a round nut 11, which can be used for being matched with various straight stroke executing mechanisms.

As shown in fig. 1, the utility model adopts a pressure balance type single seat sealing structure, namely, a valve core and valve rod assembly 5 and a guide sleeve 4 are sealed by adopting a low-leakage sealing ring 3. As shown in FIG. 8, the low leakage sealing ring 3 is made of UHMW-PE ultra-high molecular polyethylene, is a special low leakage sealing ring with excellent characteristics of low temperature resistance, high pressure resistance, impact resistance, wear resistance, good self-lubricating performance and the like, and is particularly suitable for ultralow temperature working conditions such as liquid oxygen, liquid nitrogen and the like. The pressure balance type single-seat sealing structure can relieve the influence of unbalanced force, can enable the leakage grade to meet the V-level leakage quantity requirements in the industry standards of GB/T4213-2008, IEC60534-4, ASME B16.104 and the like, and can control high pressure difference by adopting smaller actuator thrust.

From the above, the ultra-low Wen Long valve with the quick-change core-pulling structure disclosed by the utility model has the following functions and advantages:

(1) the ultralow-temperature low-leakage cage valve is developed and designed on the basis of standardization, universality and interchangeability, and has the advantages of reasonable structure, simple flow path, small flow resistance and convenience in installation. The ultralow temperature low leakage cage valve with the same caliber can meet the operation requirements of various low temperature processes only by replacing parts (valve cage) and the like.

(2) By adopting a unique long neck type extension tube structure, the heat transfer can be effectively reduced, the structural deformation and the abnormal medium pressure rise phenomenon caused by temperature change are eliminated, and the heat insulation performance and the cooling performance of the valve are ensured.

(3) In order to ensure the technical performances of impact toughness, relative elongation, wear resistance, corrosion resistance and the like of all important parts such as a valve body, an extension tube assembly, a valve cover, a valve core and valve rod assembly, a valve cage and the like at low temperature, austenitic stainless steel materials are adopted, and proper heat treatment is carried out. The 60-degree sealing lines on the valve core and the valve cage are all required to be welded with hard alloy in a surfacing mode, and then deep cooling treatment is carried out after welding. And simultaneously, before finish machining, all parts are subjected to cryogenic treatment.

(4) The valve core and valve rod assembly adopts a quick-change core-pulling structure, and parts such as the valve core, the valve rod and the like can be conveniently and rapidly pulled out and replaced without disassembling the valve body and the extension tube assembly, so that maintenance procedures and processes are simplified, equipment parking time is shortened, and field overhaul and maintenance work is simple and feasible. The design structure is particularly suitable for the ultralow temperature working condition occasion where the valve needs to be installed in the cold box.

(5) By adopting a reasonable PTFE double-layer packing sealing structure, the possibility of outward leakage of the medium from a valve rod movement gap can be eliminated, the occurrence of environmental pollution caused by medium leakage is prevented, and the personal safety is ensured.

(6) The valve core valve rod assembly is sealed with the guide sleeve by adopting a pressure balance type single seat sealing structure, namely a low leakage sealing ring. The low leakage sealing ring is made of UHMW-PE ultra-high molecular polyethylene, is a special low leakage sealing ring with excellent characteristics of low temperature resistance, high pressure resistance, impact resistance, wear resistance, good self-lubricating performance and the like, and is particularly suitable for ultra-low temperature working conditions such as liquid oxygen, liquid nitrogen and the like. The influence of unbalanced force can be relieved, and the high pressure difference can be controlled by adopting smaller actuator thrust.

(7) Good regulation and control performance and tight closing. The leakage grade can meet the V-grade leakage quantity index requirements in the industry standards of GB/T4213-2008, IEC60534-4, ASME B16.104 and the like.

(8) The installation and the disassembly are convenient, the number of vulnerable parts is small, and the maintenance is simple.

(9) According to the actual working condition and the requirements of users, any kind of straight travel driving device and corresponding accessories such as a pneumatic film type executing mechanism, a pneumatic piston type executing mechanism, a manual executing mechanism, an electric executing mechanism and the like can be matched.

The valve can meet the operation requirements of various low-temperature processes, ensures the reliable operation of the valve under the ultralow-temperature working condition, has good regulation and control performance and tight closing when the low-temperature range is used from minus 196 ℃ to minus 100 ℃. The leakage grade can meet the V-grade leakage quantity index requirement in the industry standard, is particularly suitable for the control occasions of automatic low-temperature flow technology such as ethylene petrifaction, air separation, LNG liquefied natural gas, liquefied petroleum and the like, can partially or completely replace foreign imported like products, and accords with the current national encouragement policy about localization of industrial equipment.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the utility model may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features contained in other embodiments, but not others, combinations of features of different embodiments are equally meant to be within the scope of the utility model and form different embodiments. For example, in the above embodiments, those skilled in the art can use the above embodiments in combination according to known technical solutions and technical problems to be solved by the present utility model.

The foregoing description is only illustrative of the preferred embodiment of the present utility model, and is not to be construed as limiting the utility model, but is to be construed as limiting the utility model to any simple modification, equivalent variation and variation of the above embodiments according to the technical matter of the present utility model without departing from the scope of the utility model.

Claims

1. An ultra-low Wen Long type valve with quick-change core-pulling structure, comprising:

2. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the valve body is provided with a medium inlet and a medium outlet, and an internal channel in the valve body is of an S streamline structure.

3. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the valve cage is integrally of a cylindrical structure, and is screwed into and fixed in the valve body in a threaded connection mode; four windows are evenly spaced on the annular peripheral surface of the valve cage.

4. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: a circle of 60-degree sealing line is arranged on the inner side wall of the lower portion of the valve cage and the outer side wall of the bottom of the valve core, hard alloy is needed to be deposited on the 60-degree sealing line, and cryogenic treatment is carried out after the welding.

5. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the extension tube component adopts a long-neck extension tube structure and consists of an extension tube and a connecting disc; the connecting disc is welded at the upper part of the extension tube and is used for connecting and assembling a corresponding heat-insulation sealing sleeve.

6. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: and a tooth-shaped gasket is adopted to seal between the extension tube assembly and the valve cover.

7. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the flange structure at the top of the extension tube assembly is uniformly provided with a plurality of threaded holes at intervals, and the flange structure at the bottom of the valve cover is provided with a plurality of through holes coaxial with the threaded holes;

the screw bolt penetrates through the through hole and then is screwed in the threaded hole, the nut is screwed on the screw bolt positioned on the outer side of the flange structure of the extension tube component, and the extension tube component and the valve cover are fastened together by screwing the nut.

8. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the inner wall of the valve cover is sealed with the valve rod by adopting a packing assembly; the bottom of the packing assembly is limited to axially move through a step in the valve cover, and a packing gland, a disc spring and a packing gland nut are sequentially arranged at the top of the packing assembly from bottom to top and are fixed on the valve cover through the packing gland nut to compress and fix the packing assembly.

9. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: and a low-leakage sealing ring is arranged between the opposite peripheral surfaces of the valve core and the guide sleeve.

10. The ultra-low Wen Long valve with quick change core pulling structure of claim 1, wherein: the guide sleeve is connected with the valve body in a welding mode; the lower end of the extension tube component is connected with the guide sleeve in a welding mode.