Composite filler control valve

Abstract

The utility model discloses a composite packing control valve, which can enable the composite packing control valve to still keep a good sealing effect under a low-temperature working condition, and can reduce abrasion of each sealing structure in a packing assembly, thereby prolonging the service life of the composite packing control valve. The composite filler control valve comprises a valve body (8), a valve rod (12), a gland (1) and a filler assembly. And the valve rod (12) penetrates through the valve body (8). The packing assembly sequentially comprises an upper packing assembly, an elastic pressing assembly and a lower packing assembly from top to bottom. The elastic pressing assembly is used for providing pressing force for the bottom face of the upper packing assembly and the top face of the lower packing assembly. The upper packing assembly sequentially comprises a lining (4), a carbon fiber ring (5), a forming graphite ring (6), a double-layer V-shaped graphite ring (7) and a forming graphite ring (6) from top to bottom. The lower packing assembly sequentially comprises a forming graphite ring (6), a double-layer V-shaped graphite ring (7), a forming graphite ring (6) and a carbon fiber ring (5) from top to bottom.

Description

Technical Field

[0001] The utility model specifically relates to a composite packing control valve. Background Art

[0002] Ball valves, butterfly valves, etc. operating at normal temperature generally adopt metal or non-metal material sealing pairs. Since non-metal materials have large elasticity and require a small specific pressure to obtain sealing, the sealing performance is good. However, at low temperatures, due to the much larger expansion coefficient of non-metal materials than that of metal materials, the shrinkage amount of non-metal materials at low temperatures is quite different from that of mating parts such as metal seals and valve bodies, resulting in a serious reduction in the sealing specific pressure and an inability to seal. Most non-metal materials become hard and brittle at cryogenic temperatures, losing toughness, resulting in cold flow and stress relaxation.

[0003] In the cold hydrogenation process and tail gas recovery process of polysilicon production, it is necessary to control the parameters of cryogenic media. A large number of control valves are in low-temperature working conditions, and valve packing seals are prone to failure during use, seriously affecting process production; after long-term use, the control valves are severely worn, further reducing the sealing effect of the control valves. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a composite packing control valve aiming at the above deficiencies existing in the prior art, which can enable the composite packing control valve to still maintain good sealing performance under low-temperature working conditions, and can reduce the wear of each sealing structure in the packing assembly, thereby extending the service life of the composite packing control valve.

[0005] In a first aspect, an embodiment of the utility model provides a composite packing control valve, which includes a valve body, a valve stem, a gland, and a packing assembly. The valve stem penetrates through the valve body. The gland is fixed above the valve body and is used to compress the packing assembly; the area between the valve body, the valve stem, and the gland forms a packing cavity. The packing assembly is arranged in the packing cavity, and the packing assembly successively includes an upper packing assembly, an elastic compression assembly, and a lower packing assembly from top to bottom; the elastic compression assembly is used to provide a compression force to the bottom surface of the upper packing assembly and the top surface of the lower packing assembly. The upper packing assembly successively includes a bushing, a carbon fiber ring, a formed graphite ring, a double-layer V-shaped graphite ring, and a formed graphite ring from top to bottom. The lower packing assembly successively includes a formed graphite ring, a double-layer V-shaped graphite ring, a formed graphite ring, and a carbon fiber ring from top to bottom.

[0006] In some embodiments, the carbon fiber ring is a carbon fiber packing woven into a grid shape.

[0007] In some embodiments, the outer surface of the carbon fiber ring is impregnated with polytetrafluoroethylene.

[0008] In some embodiments, the material of the double-layer V-shaped graphite ring is flexible graphite.

[0009] In some embodiments, the double-layer V-shaped graphite ring includes an upper V-shaped ring and a lower V-shaped ring connected to each other. The angle α between the inner end face of the upper V-shaped ring and the horizontal plane satisfies 20° ≤ α ≤ 45°; the angle β between the inner end face of the lower V-shaped ring and the horizontal plane satisfies 20° ≤ β ≤ 45°.

[0010] In some embodiments, annular grooves are provided on both the inner side wall and the outer side wall of the bushing, and sealing rings are provided in the annular grooves.

[0011] In some embodiments, the elastic compression assembly sequentially includes an upper compression spring, a lantern sleeve, and a lower compression spring from top to bottom. The lantern sleeve is sleeved on the valve stem and is located between the upper packing assembly and the lower packing assembly. The upper compression spring is sleeved on the upper end portion of the lantern sleeve and abuts against the upper packing assembly. The lower compression spring is sleeved on the lower end portion of the lantern sleeve and abuts against the lower packing assembly.

[0012] In some embodiments, a first gasket is provided between the upper compression spring and the formed graphite ring in the upper packing assembly in contact therewith. A second gasket is provided between the lower compression spring and the formed graphite ring in the lower packing assembly in contact therewith.

[0013] In some embodiments, the cross-sectional shape of the lantern sleeve is I-shaped.

[0014] In some embodiments, buffer air holes are provided on the vertical support plate of the lantern sleeve.

[0015] Thus, in the composite packing control valve of the embodiment of the present utility model, by providing a gland, the packing assembly can be tightly pressed. By providing an upper packing assembly, an elastic pressing assembly and a lower packing assembly in the packing assembly, the elastic pressing assembly can provide a pressing force to the bottom surface of the upper packing assembly and the top surface of the lower packing assembly. Among them, the upper packing assembly sequentially includes a bushing, a carbon fiber ring, a formed graphite ring, a double-layer V-shaped graphite ring and a formed graphite ring from top to bottom, and the lower packing assembly sequentially includes a formed graphite ring, a double-layer V-shaped graphite ring, a formed graphite ring and a carbon fiber ring from top to bottom. The bushing can be used as the seal of the last layer of the packing assembly; the carbon fiber material has strong chemical stability and wear resistance, which can prevent the carbon fiber ring from being corroded by the medium in the valve body and improve the service life of the carbon fiber ring; moreover, the carbon fiber ring also has a good low expansion coefficient, which can ensure the low deformation amount and sealing effect of the carbon fiber ring under high-pressure and low-temperature working conditions. The formed graphite ring has good pressure resistance and can maintain its own shape under high pressure, so it can well transmit pressure, enabling the sealing structures between the upper packing assembly and the lower packing assembly to be tightly pressed against each other to achieve the effect of sufficient exhaust and improve the overall sealing performance of the upper packing assembly and the lower packing assembly; after being compressed, the double-layer V-shaped graphite ring expands inside and outside its wedge-shaped opening, which can play a full sealing role between the valve stem and the valve body, further improving the overall sealing performance of the upper packing assembly and the lower packing assembly. And due to the lubricating effect of graphite, the wear of the formed graphite ring and the double-layer V-shaped graphite ring can be reduced. Due to the low-temperature resistance of graphite, the formed graphite ring and the double-layer V-shaped graphite ring are also suitable for low-temperature working conditions. In summary, the composite packing control valve in this embodiment can maintain a good sealing effect under low-temperature working conditions and reduce the wear of each sealing structure in the packing assembly, thereby extending the service life of the composite packing control valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : A partial schematic diagram of a composite packing control valve provided by an embodiment of the present utility model;

[0017] Figure 2 : A longitudinal sectional view of a lantern sleeve provided by an embodiment of the present utility model;

[0018] Figure 3 : A top view of a lantern sleeve provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To enable those skilled in the art to better understand the technical solutions of the present utility model, the present utility model will be further described in detail below with reference to the drawings and embodiments.

[0020] Embodiment 1:

[0021] As Figure 1As shown in the figure, an embodiment of the present utility model provides a composite packing control valve, which is applied to the pipeline transportation of fluids. For example, it is applied to the pipeline in the process of recovering tail gas in polysilicon production, and can conduct or close the pipeline.

[0022] As Figure 1 shown in the figure, the composite packing control valve includes a valve body 8, a valve stem 12, a gland 1 and a packing assembly. The valve stem 12 penetrates through the valve body 8. The gland 1 is fixed above the valve body 8 and is used to compress the packing assembly. The area between the valve body 8, the valve stem 12 and the gland 1 forms a packing cavity. The packing assembly is arranged in the packing cavity.

[0023] The valve stem 12 can rotate relative to the valve body 8 to conduct or close the valve body 8.

[0024] Exemplarily, as Figure 1 shown in the figure, the gland 1 is fixed above the valve body 8 through bolts 2. By rotating the bolts 2, the compression force of the gland 1 on the packing assembly can be adjusted.

[0025] In practical applications, the bolts 2 are locked with a torque of 60 N·m - 90 N·m.

[0026] It can be understood that the shape of the packing cavity is an annular cavity. The bottom surface of the packing assembly arranged in the packing cavity contacts the medium in the valve body 8, and through the sealing of the packing assembly, the medium in the valve body 8 can be prevented from leaking through the packing cavity.

[0027] Exemplarily, the medium in the valve body 8 can be a mixed gas of trichlorosilane, tetrachlorosilane and hydrogen chloride at -60°C to -100°C.

[0028] In practical applications, the size of the valve stem 12 and the size of the packing cavity are set according to parameters such as the type of medium and the diameter of the connected pipeline.

[0029] Taking the example that the composite packing control valve is used for pipelines with a diameter of more than DN300, the size of the valve stem 12 can be Φ45 mm, the inner diameter size of the packing cavity is 45 mm, and the outer diameter size is 65 mm.

[0030] As Figure 1 shown in the figure, the packing assembly includes an upper packing assembly, an elastic compression assembly and a lower packing assembly from top to bottom; the elastic compression assembly is used to provide a compression force to the bottom surface of the upper packing assembly and the top surface of the lower packing assembly. The upper packing assembly includes a bushing 4, a carbon fiber ring 5, a formed graphite ring 6, a double-layer V-shaped graphite ring 7 and a formed graphite ring 6 from top to bottom. The lower packing assembly includes a formed graphite ring 6, a double-layer V-shaped graphite ring 7, a formed graphite ring 6 and a carbon fiber ring 5 from top to bottom.

[0031] It can be understood that each sealing structure included in the packing assembly (including the bushing 4, carbon fiber ring 5, formed graphite ring 6, and double-layer V-shaped graphite ring, the same below) is sleeved on the valve stem 12, and the sizes of each sealing structure included in the packing assembly are all adapted to the size of the packing cavity, so that each sealing structure can maintain a good sealing effect in the packing cavity.

[0032] For example, when the inner diameter size of the packing cavity is 45 mm and the outer diameter size is 65 mm, the inner diameter size of each sealing structure included in the packing assembly is 45 mm and the outer diameter size is 65 mm.

[0033] In the upper packing assembly, the bushing 4 is used for the sealing of the last layer of the packing assembly to prevent the escape-type leakage of the medium in the valve body 8.

[0034] The material of the bushing 4 can be materials such as metal or rubber.

[0035] In some examples, annular grooves are provided on both the inner side wall and the outer side wall of the bushing 4, and sealing rings are provided in the annular grooves.

[0036] Exemplarily, the outer diameter of the cross-section of the sealing ring is 5 mm. When installing the bushing 4, lubricating oil is first filled in the valve body 8 to improve the lubrication performance of the sealing ring.

[0037] Exemplarily, the material of the sealing ring is nitrile rubber. The sealing ring made of nitrile rubber material has the characteristics of wear resistance, high pressure resistance, and anti-solubility, which is beneficial to extending the service life of the sealing ring, thereby maintaining the sealing effect of the sealing ring and the bushing 4.

[0038] In the lower packing assembly, the lowermost carbon fiber ring 5 is used for the filling and sealing of the bottom of the lower packing assembly. In the upper packing assembly, the uppermost carbon fiber ring 5 is used for the filling and sealing of the top of the upper packing assembly.

[0039] The carbon fiber material has strong chemical stability, which can prevent the carbon fiber ring 5 from being corroded by the medium in the valve body 8 and improve the service life of the carbon fiber ring 5. And the carbon fiber ring 5 has high wear resistance, and its friction coefficient is also small, which can reduce the wear of the carbon fiber ring 5 during use, so that the carbon fiber ring 5 can maintain a good sealing performance for a long time.

[0040] The carbon fiber ring 5 also has a good low expansion coefficient, and can have an extremely low cold shrinkage amount under high-pressure and low-temperature working conditions (such as trichlorosilane, tetrachlorosilane, and hydrogen chloride high-pressure gases with a temperature between -60 °C and -100 °C), thereby reducing the deformation amount and ensuring the sealing effect of the carbon fiber ring 5.

[0041] Exemplarily, the formed graphite ring 6 is a layered graphite pressing.

[0042] The formed graphite ring 6 has good pressure resistance and can maintain its shape under high pressure, so it can transmit pressure well.

[0043] As Figure 1 shown, in the upper packing assembly, the pressing force of the gland 1 on the packing assembly can be transmitted downward through the bushing 4, the carbon fiber ring 5, and the formed graphite ring 6, and the upward pressing force of the elastic pressing assembly can be transmitted upward through the formed graphite ring 6, so that the sealing structures in the upper packing assembly are pressed against each other to achieve the function of fully exhausting air and improve the overall sealing performance of the upper packing assembly.

[0044] Similarly, as Figure 1 shown, in the lower packing assembly, the downward pressing force of the elastic pressing assembly can be transmitted downward through the formed graphite ring 6, and the pressure of the medium in the valve body 8 is sequentially transmitted upward through the carbon fiber ring 5 and the formed graphite ring 6, so that the sealing structures in the lower packing assembly are pressed against each other to achieve the function of fully exhausting air and improve the overall sealing performance of the lower packing assembly.

[0045] As described above, in the upper packing assembly and the lower packing assembly, the double-layer V-shaped graphite ring 7 will be squeezed by the formed graphite rings 6 on both sides. After being compressed, the wedge-shaped openings of the double-layer V-shaped graphite ring 7 expand inward and outward, which can play a full sealing role between the valve stem 12 and the valve body 8, and further improve the overall sealing performance of the upper packing assembly and the lower packing assembly.

[0046] Furthermore, since the double-layer V-shaped graphite ring 7 expands radially preferentially near its V-shaped structure after being compressed, a locally high-stress annular region is formed, and the contact stress of the sealing surface far from the V-shaped structure is small, thus establishing an approximate "labyrinth seal" effect; in addition, the local preferential expansion of the V-shaped structure is also beneficial to the compaction and radial expansion of the bottom layer packing of the double-layer V-shaped graphite ring 7.

[0047] Moreover, due to the self-lubricating property of graphite, the frictional forces between the formed graphite ring 6, the double-layer V-shaped graphite ring 7 and the valve body 8, the valve stem 12 are also small, reducing the wear of the formed graphite ring 6, the double-layer V-shaped graphite ring 7, and improving the service life of the formed graphite ring 6, the double-layer V-shaped graphite ring 7. The low-temperature resistance of graphite enables the formed graphite ring 6, the double-layer V-shaped graphite ring 7 to be suitable for low-temperature working conditions.

[0048] Thus, in the composite packing control valve according to the embodiment of the present utility model, by providing a gland 1, the packing assembly can be tightly pressed. By providing an upper packing assembly, an elastic pressing assembly and a lower packing assembly in the packing assembly, the elastic pressing assembly can provide a pressing force to the bottom surface of the upper packing assembly and the top surface of the lower packing assembly. Among them, the upper packing assembly successively includes a bushing 4, a carbon fiber ring 5, a formed graphite ring 6, a double-layer V-shaped graphite ring 7 and a formed graphite ring 6 from top to bottom, and the lower packing assembly successively includes a formed graphite ring 6, a double-layer V-shaped graphite ring 7, a formed graphite ring 6 and a carbon fiber ring 5 from top to bottom. The bushing 4 can be used as the seal of the last layer of the packing assembly; the carbon fiber material has strong chemical stability and wear resistance, which can prevent the carbon fiber ring 5 from being corroded by the medium in the valve body 8 and improve the service life of the carbon fiber ring 5; moreover, the carbon fiber ring 5 also has a good low expansion coefficient, which can ensure a low deformation amount and sealing effect of the carbon fiber ring 5 under high-pressure and low-temperature working conditions. The formed graphite ring 6 has good pressure resistance and can maintain its own shape under high pressure. Therefore, it can well transmit pressure, enable the sealing structures of the upper packing assembly and the lower packing assembly to be pressed against each other to achieve the effect of full exhaust, and improve the overall sealing performance of the upper packing assembly and the lower packing assembly; after being compressed, the double-layer V-shaped graphite ring 7 expands inside and outside its wedge-shaped opening, which can play a full sealing role between the valve stem 12 and the valve body 8, further improving the overall sealing performance of the upper packing assembly and the lower packing assembly. And because of the lubrication effect of graphite, the wear of the formed graphite ring 6 and the double-layer V-shaped graphite ring 7 can be reduced. Because of the low-temperature resistance of graphite, the formed graphite ring 6 and the double-layer V-shaped graphite ring 7 are also suitable for low-temperature working conditions. In summary, the composite packing control valve in this embodiment can maintain a good sealing effect under low-temperature working conditions and reduce the wear of each sealing structure in the packing assembly, thereby extending the service life of the composite packing control valve.

[0049] Moreover, in the composite packing control valve of this embodiment, the upper packing assembly includes six sealing structures including a bushing 4, a carbon fiber ring 5, a formed graphite ring 6, a double-layer V-shaped graphite ring 7 and a formed graphite ring 6, and the lower packing assembly includes five sealing structures including a formed graphite ring 6, a double-layer V-shaped graphite ring 7, a formed graphite ring 6 and a carbon fiber ring 5. The number of sealing structures is within a reasonable range, which can reduce the resistance exerted on the valve stem 12 by each sealing structure on the basis of ensuring the sealing effect of the composite packing control valve, thereby solving the problem that the valve stem 12 is difficult to rotate in the prior art due to the too deep packing cavity and too many sealing structures in the packing assembly.

[0050] It should be noted that the carbon fiber ring 5, the formed graphite ring 6 and the double-layer V-shaped graphite ring 7 also have the characteristics of high temperature resistance and high heat conductivity, which can effectively prevent heat accumulation from causing a decrease in the performance and service life of the sealing structures in the packing assembly. Therefore, the above-mentioned composite packing control valve can also be applicable to high-temperature (+455°C to +650°C) working conditions.

[0051] In some examples, the thicknesses of the carbon fiber ring 5 and the formed graphite ring 6 are both 10 mm.

[0052] In some embodiments, the carbon fiber ring 5 is a carbon fiber packing woven into a grid shape.

[0053] The carbon fiber packing has excellent thermal conductivity, wear resistance and chemical stability. The carbon fiber packing woven into a grid shape can improve the filling performance of the carbon fiber ring 5.

[0054] In some embodiments, the outer surface of the carbon fiber ring 5 is impregnated with polytetrafluoroethylene.

[0055] Through the above settings, the corrosion resistance of the carbon fiber ring 5 can be improved, so that the composite packing control valve can be applied to acidic, alkaline, oxidizing and other media, and the versatility of the composite packing control valve can be improved.

[0056] In some examples, the formed graphite ring 6 can be an isodensity graphite ring or a graphite ring with a density gradient.

[0057] When using an isodensity graphite ring, the density of the formed graphite ring 6 is greater than or equal to 1.6 g / cm 3 .

[0058] Using the formed graphite ring 6 with a density gradient can further improve the sealing performance and tribological performance of the formed graphite ring 6.

[0059] In some embodiments, the material of the double-layer V-shaped graphite ring 7 is flexible graphite.

[0060] This can cause the double-layer V-shaped graphite ring 7 to form a radial deformation under pressure and fill the packing cavity, thereby improving the sealing performance of the double-layer V-shaped graphite ring 7.

[0061] In some embodiments, the double-layer V-shaped graphite ring 7 includes an upper V-shaped ring and a lower V-shaped ring connected to each other. The included angle α between the inner end face of the upper V-shaped ring and the horizontal plane satisfies 20° ≤ α ≤ 45°; the included angle β between the inner end face of the lower V-shaped ring and the horizontal plane satisfies 20° ≤ β ≤ 45°.

[0062] Exemplarily, the included angle α between the inner end face of the upper V-shaped ring and the horizontal plane can be 20°, 35° or 45°, etc.; the included angle β between the inner end face of the lower V-shaped ring and the horizontal plane can be 20°, 35° or 45°, etc.

[0063] When the double-layer V-shaped graphite ring 7 is under pressure, the inner end faces of the upper V-shaped ring and the lower V-shaped ring deform towards the inner wall of the packing cavity, and an excellent sealing effect can be achieved.

[0064] With the above settings, the double-layer V-shaped graphite ring 7 can achieve good deformation under a relatively small extrusion force, so as to obtain a good sealing effect, which is beneficial to reducing the pressing force of the gland 1 on the packing assembly, and thus reducing the pre-tightening force of the bolt 2.

[0065] In some embodiments, as Figure 1 and Figure 2 shown, the elastic pressing assembly sequentially includes an upper compression spring, a lantern sleeve 11 and a lower compression spring from top to bottom. The lantern sleeve is sleeved on the valve stem 12 and is located between the upper packing assembly and the lower packing assembly. The upper compression spring is sleeved on the upper end of the lantern sleeve and abuts against the upper packing assembly. The lower compression spring is sleeved on the lower end of the lantern sleeve and abuts against the lower packing assembly.

[0066] Exemplarily, the material of the lantern sleeve 11 can be selected according to the medium in the valve body 8.

[0067] For example, the material of the lantern sleeve 11 can be 316L stainless steel.

[0068] Exemplarily, the middle part of the lantern sleeve 11 is milled to improve smoothness, which can effectively reduce the friction between the lantern sleeve 11 and the valve stem 12 and increase the sealing performance between the lantern sleeve 11 and the valve stem 12.

[0069] It can be understood that the upper compression spring abuts against the formed graphite ring 6 at the bottom of the upper packing assembly, and the lower compression spring abuts against the formed graphite ring 6 at the top of the lower packing assembly, so as to respectively transfer the pressing force of the spring through the formed graphite ring 6.

[0070] With the above settings, the pressure can be transmitted in the packing cavity through the upper compression spring and the lower compression spring, so that the stress between each layer of the sealing structure of the packing assembly can be balanced and fully pressed. In addition, if the medium in the valve body 8 leaks through the lower packing assembly, the leaked medium will first enter the space in the upper compression spring and the lower compression spring for storage and buffering, preventing the leaked medium from directly passing upward through the upper packing assembly, and the gas in the upper compression spring and the lower compression spring also has a sealing effect.

[0071] On the other hand, by using upper compression springs and lower compression springs with different lengths and stiffnesses, the total length of the packing assembly can be flexibly adjusted, so that the packing assembly can be applied to packing cavities of various depths.

[0072] In some embodiments, as Figure 1 shown, a first gasket is provided between the upper compression spring and the formed graphite ring 6 in the upper packing assembly in contact therewith. A second gasket 13 is provided between the lower compression spring and the formed graphite ring 6 in the lower packing assembly in contact therewith.

[0073] The first gasket can evenly apply the elastic force of the upper compression spring to the molded graphite ring 6 in the upper packing assembly in contact with it, and the second gasket 13 can evenly apply the elastic force of the lower compression spring to the molded graphite ring 6 in the lower packing assembly in contact with it.

[0074] In some embodiments, Figure 1 As shown, the cross-sectional shape of the lantern sleeve 11 is an I-shape.

[0075] like Figure 1 As shown, two sealed chambers can be formed between the lantern sleeve 11 and the valve body 8, and between the lantern sleeve 11 and the valve stem 12. If the medium in the valve body 8 leaks through the lower packing assembly, the leaked medium will first enter the above-mentioned two sealed chambers for storage for buffering to prevent the leaked medium from being directly transmitted upward through the upper packing assembly, and the gas in the two sealed chambers also has a sealing effect.

[0076] The above arrangement can also reduce the contact area between the lantern sleeve 11 and the valve body 8, and between the lantern sleeve 11 and the valve stem 12, thereby reducing friction and reducing the resistance when the valve stem 12 rotates.

[0077] In some embodiments, Figure 1 As shown, a buffer air hole 9 is provided on the vertical support plate of the lantern sleeve 11.

[0078] For example, Figure 3 As shown, there are four buffer air holes 9 , and the four buffer air holes 9 are evenly distributed along the center of the lantern sleeve 11 .

[0079] Exemplarily, the diameter of the buffer pore 9 is 2 mm.

[0080] The buffer air hole 9 can connect the two sealed chambers to balance the pressure between the two sealed chambers, and allow the medium that enters one of the sealed chambers due to leakage to enter the other sealed chamber, thereby increasing the capacity of the medium that can be stored and allowing the composite packing control valve to remain sealed for a long time.

[0081] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A composite packing control valve, characterized in that, Comprising: Valve body (8); Valve stem (12), passing through the valve body (8); Gland (1), fixed above the valve body (8) for pressing the packing assembly; the area between the valve body (8), the valve stem (12) and the gland (1) forms a packing chamber; and, Packing assembly, arranged in the packing chamber, the packing assembly successively includes an upper packing assembly, an elastic pressing assembly and a lower packing assembly from top to bottom; the elastic pressing assembly is used to provide a pressing force to the bottom surface of the upper packing assembly and the top surface of the lower packing assembly; The upper packing assembly successively includes a bushing (4), a carbon fiber ring (5), a molded graphite ring (6), a double-layer V-shaped graphite ring (7) and a molded graphite ring (6) from top to bottom; The lower packing assembly successively includes a molded graphite ring (6), a double-layer V-shaped graphite ring (7), a molded graphite ring (6) and a carbon fiber ring (5) from top to bottom.

2. The composite packing control valve according to claim 1, wherein The carbon fiber ring (5) is a carbon fiber packing braided into a grid shape.

3. The composite packing control valve according to claim 2, characterized in that, The outer surface of the carbon fiber ring (5) is impregnated with polytetrafluoroethylene.

4. The composite packing control valve according to claim 1, characterized in that, The material of the double-layer V-shaped graphite ring (7) is flexible graphite.

5. The composite packing control valve according to claim 4, characterized in that, The double-layer V-shaped graphite ring (7) includes an upper V-shaped ring and a lower V-shaped ring connected to each other; The included angle α between the inner end surface of the upper V-shaped ring and the horizontal plane satisfies 20° ≤ α ≤ 45°; The included angle β between the inner end surface of the lower V-shaped ring and the horizontal plane satisfies 20° ≤ β ≤ 45°.

6. The composite packing control valve according to claim 1, wherein Annular grooves are provided on both the inner side wall and the outer side wall of the bushing (4), and sealing rings are provided in the annular grooves.

7. The composite packing control valve according to claim 1, wherein The elastic pressing assembly successively includes an upper compression spring, a lantern sleeve (11) and a lower compression spring from top to bottom; The lantern sleeve is sleeved on the valve stem (12) and is located between the upper packing assembly and the lower packing assembly; The upper compression spring is sleeved on the upper end portion of the lantern sleeve and abuts against the upper packing assembly; The lower compression spring is sleeved on the lower end portion of the lantern sleeve and abuts against the lower packing assembly.

8. The composite packing control valve according to claim 7, characterized in that, A first gasket is provided between the upper compression spring and the molded graphite ring (6) in the upper packing assembly in contact therewith; A second gasket (13) is provided between the lower compression spring and the molded graphite ring (6) in the lower packing assembly in contact therewith.

9. The composite packing control valve according to claim 7, wherein, The cross-sectional shape of the lantern sleeve (11) is an I shape.

10. The composite packing control valve according to claim 7, wherein Buffer air holes (9) are provided on the vertical support plate of the lantern sleeve (11).

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