Valve plug, valve assembly and gas turbine fuel nozzle

Abstract

The present invention provides a valve plug for fitting into a cylinder hole of a valve cylinder having a vertical hole section. The valve plug includes a columnar platform having a through hole penetrating vertically up and down for fluid to flow from the upper side to the lower side of the columnar platform. Moreover, the lateral dimension of the columnar platform gradually decreases from the upper column end towards the lower column end, and the upper column end of the columnar platform is arranged to have a clearance fit with the vertical hole section. The present invention also provides a valve assembly and a gas turbine fuel nozzle including the above-mentioned valve plug. When the above-mentioned valve plug is fitted with the valve cylinder, it can meet the requirements of the fitting clearance while avoiding the accumulation of fuel impurities in the clearance between the valve plug and the valve cylinder.

Description

Technical Field

[0001] The present invention relates to a valve plug, and also relates to a valve assembly including the valve plug and a fuel nozzle of a gas turbine. Background Art

[0002] Modern gas turbine fuel nozzles generally use a valve assembly to regulate the fuel flow. The valve assembly generally includes a valve plug, a valve cylinder, a spring, etc. When the gas turbine switches its working state, the valve plug moves relative to the valve cylinder. By changing the area of the oil leakage window between the valve plug and the valve cylinder, the fuel flow regulation function is achieved. The fit clearance between the valve plug and the valve cylinder is very important for the performance of the valve assembly. When the clearance is too large, fuel will leak from the clearance, and the valve assembly cannot achieve the sealing function. When the clearance is too small, the valve plug and the valve cylinder are prone to jamming during relative movement, resulting in a large fuel lag rate and unable to meet the valve performance requirements.

[0003] The inventor found that during the operation of the valve, fine impurities in the fuel will accumulate in the clearance between the valve plug and the valve cylinder, increasing the friction between the valve plug and the valve cylinder, affecting the fuel lag rate, causing the working state of the valve to be unstable, and affecting the performance and safety of the fuel nozzle.

[0004] Therefore, it is necessary to provide a valve assembly that can solve the problem of fuel impurities accumulating in the clearance between the valve plug and the valve cylinder during long-term operation of the valve while meeting the fit clearance requirements. Summary of the Invention

[0005] One object of the present invention is to provide a valve plug that can meet the fit clearance requirements while avoiding fuel impurities from accumulating in the clearance between the valve plug and the valve cylinder when mating with the valve cylinder.

[0006] Another object of the present invention is to provide a valve assembly that can meet the fit clearance requirements while avoiding fuel impurities from accumulating in the clearance between the valve plug and the valve cylinder.

[0007] Another object of the present invention is to provide a fuel nozzle of a gas turbine that can avoid the situation of fuel impurities accumulating in the clearance between the valve plug and the valve cylinder.

[0008] The present invention provides a valve plug for fitting in a cylinder hole of a valve cylinder having a vertical hole section. The valve plug includes a column platform. The column platform has a through hole penetrating up and down for fluid to flow from the upper side to the lower side of the column platform. And the lateral dimension of the column platform gradually decreases from the upper column end to the lower column end. And the upper column end of the column platform is arranged to have a clearance fit with the vertical hole section.

[0009] In one embodiment, the outer column surface of the column platform is a conical surface.

[0010] In one embodiment, the taper of the conical surface is 1:20 to 1:100.

[0011] In one embodiment, the valve plug further includes: a boss, connected below the columnar platform through a journal section and configured to be adapted in the vertical hole section, and a drainage groove extending vertically and recessed inwardly is provided on the outer peripheral surface of the boss, and the upper end side of the drainage groove is open; and a cover platform, connected to the lower side of the boss for sealing the vertical hole section from the lower side, and the lower end side of the drainage groove is closed on the upper side of the cover platform.

[0012] The present invention also provides a valve assembly, including a valve cylinder and a valve plug. The cylinder hole of the valve cylinder has a vertical hole section. The valve plug includes a columnar platform. The columnar platform has a through hole penetrating up and down for fluid to flow from the upper side of the columnar platform to the lower side. And the lateral dimension of the columnar platform gradually decreases from the upper column end to the lower column end, and the upper column end of the columnar platform is in clearance fit with the vertical hole section. Thus, the valve plug is adapted in the vertical hole section.

[0013] In one embodiment, the outer columnar surface of the columnar platform is a conical surface.

[0014] In one embodiment, the taper of the conical surface is 1:20 to 1:100.

[0015] In one embodiment, the cylinder hole of the valve cylinder is provided with an inlet for introducing the fluid and an outlet for discharging the fluid, and the inlet is provided on the upper side of the columnar platform; the outlet is provided on the hole wall of the vertical hole section. As the valve plug moves up and down relative to the valve cylinder, the area of the outlet blocked by the outer columnar surface of the columnar platform gradually changes, thereby adjusting the fluid flow rate flowing out from the outlet.

[0016] In one embodiment, the valve plug further includes: a boss, connected below the columnar platform through a journal section and adapted in the vertical hole section, and a drainage groove extending vertically and recessed inwardly is provided on the outer peripheral surface of the boss, and the upper end side of the drainage groove is open; and a cover platform, connected to the lower side of the boss for sealing the vertical hole section from the lower side, and the lower end side of the drainage groove is closed on the upper side of the cover platform. As the valve plug moves up and down relative to the valve cylinder, the area of the notch of the drainage groove exposed below the vertical hole section gradually changes, thereby adjusting the fluid flow rate discharged from the drainage groove.

[0017] The present invention also provides a gas turbine fuel nozzle having the above-mentioned valve assembly, and the outlet or drainage groove of the valve assembly leads to the main combustion stage or pre-combustion stage of the combustion chamber.

[0018] When the above-mentioned valve plug, valve assembly and gas turbine fuel nozzle are adopted, the transverse dimension of the column platform of the valve plug gradually decreases from the upper column end with clearance fit with the vertical hole section of the valve cylinder towards the lower column end. Therefore, the fit clearance between the valve plug and the valve cylinder can be continuously increased. When impurities in the fuel enter this fit clearance, the fuel will flush out the impurities from this fit clearance, and the situation of fuel impurities accumulating and blocking in the fit clearance will not occur. Moreover, the fit clearance between the column platform of the valve plug and the vertical hole section can be satisfied through the clearance fit at the upper column end, so the requirements for the fit clearance will not be affected. Therefore, when the above-mentioned valve plug, valve assembly and gas turbine fuel nozzle are adopted, while meeting the requirements for the fit clearance, the problem of the increase in fuel lag rate caused by the long-term operation of the valve assembly can be avoided, the unstable working state of the valve can be avoided, and the performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, properties and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, wherein:

[0020] Figure 1 is a perspective view of an exemplary valve plug according to the present invention.

[0021] Figure 2 is a schematic view of an exemplary valve assembly according to the present invention.

[0022] Figure 3 is a partial enlarged view of the valve assembly at the fit clearance. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The present invention will be further described below in conjunction with the detailed description of the embodiments and the drawings. More details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from this description. Those skilled in the art can make similar generalizations and deductions according to the actual application situation without departing from the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this detailed description.

[0024] For example, when it is described in the specification that the first feature is formed above or on the second feature, it may include an embodiment in which the first feature and the second feature are formed by a direct connection, and may also include an embodiment in which additional features are formed between the first feature and the second feature, so that the first feature and the second feature may not be directly connected. Further, when the first element is described in a manner of being connected or combined with the second element, this description includes an embodiment in which the first element and the second element are directly connected or combined with each other, and also includes an embodiment in which one or more other intervening elements are added to indirectly connect or combine the first element and the second element.

[0025] Figure 1The structure of an exemplary valve plug 10 is shown. Figure 2 The structure of a valve assembly 100 including the valve plug 10 is shown, while Figure 3 is shown enlarged in part to illustrate Figure 2 the mating condition of the valve plug 10 and the valve cylinder 20 in. It should be understood that the drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0026] Refer to Figure 2 , the valve plug 10 is adapted to fit in the cylinder bore 200 of the valve cylinder 20 having a vertical hole section 201. The valve plug 10 may include a column platform 1. In combination with Figure 1 , the column platform 1 has a through hole 12 penetrating vertically up and down for fluid to flow from the upper side to the lower side of the column platform 1. In the illustrated embodiment, the column platform 1 may have a plurality of through holes 12 distributed circumferentially along C0.

[0027] Refer to Figure 3 , the lateral dimension of the column platform 1 gradually decreases from the upper column end 14 towards the lower column end 15. The upper column end 14 of the column platform 1 is arranged to have a clearance fit with the vertical hole section 201. In other words, the maximum diameter of the column platform 1 (i.e., the diameter D14 of the column platform 1 at its upper column end 14) is arranged to allow the column platform 1 to fit in the cylinder bore 200 of the valve cylinder 20.

[0028] Continuing to refer to Figure 2 , the valve assembly 10 includes a valve cylinder 20 and a valve plug 10. As described above, the cylinder bore 200 of the valve cylinder 20 has a vertical hole section 201, and the upper column end 14 of the column platform 1 has a clearance fit with the vertical hole section 201, whereby the valve plug 10 fits in the vertical hole section 201.

[0029] In the text, reference is made to Figure 2 the use of spatial relationship terms such as "upper", "lower", "vertical", "lateral", etc. to describe the relationship between one element or feature shown in the drawings and other elements or features is only for convenience of description. It should be understood that these spatial relationship terms are intended to include other directions of the elements or components in use or operation, in addition to the directions depicted in the drawings. For example, if the components in the drawings are flipped, the direction of the element described as "below" other elements or features will be changed to "above" the said other elements or features, and therefore, the spatial relationship description terms used in the text should be interpreted accordingly.

[0030] When the above-mentioned valve plug 10 is adopted, the column base 1 gradually decreases in transverse dimension from the upper column end 14 which is in clearance fit with the vertical hole section 201 towards the lower column end 15. That is, in a form that tapers from top to bottom (i.e., from the inflow side of the perforation 12 towards the outflow side), the clearance between the valve plug 10 and the valve cylinder 20 can continuously increase. When impurities in a fluid such as fuel enter the clearance between the valve plug 10 and the valve cylinder 20, the fuel will flush the impurities out of the clearance between the valve plug 10 and the valve cylinder 20, and the situation of fuel impurities accumulating and blocking in the clearance will not occur. Moreover, the clearance between the column base 1 and the vertical hole section 201 can be satisfied by the clearance fit of the upper column end 14, thus not affecting the requirements for the clearance fit.

[0031] Moreover, when the above-mentioned valve plug 10 is adopted, since the clearance between the valve plug 10 and the valve cylinder 20 is crucial, it is difficult to achieve the required dimensional and geometric tolerance requirements of the parts only by turning and milling. Therefore, when machining a valve plug with a straight cylindrical surface at present, a certain amount of allowance is generally reserved after machining, and then the valve plug and the valve cylinder are manually ground with abrasive paste during the debugging process to ensure their clearance. This processing method has a large workload, poor consistency, and a low qualified rate of parts. In the above-mentioned valve plug 10, the column base 1 is in a form that tapers from top to bottom. Therefore, only the upper column end 14 has high dimensional accuracy requirements, while the requirements for the part towards the lower column end 15 can be appropriately reduced. Thus, machining can be completely carried out by machine, which can greatly reduce the workload and improve the consistency and qualified rate of parts at the same time.

[0032] See Figure 2 , in the valve assembly 100, an inflow port 202a for introducing fluid and an outflow port 202b for discharging fluid are provided in the cylinder hole 200 of the valve cylinder 20 ( Figure 3 shown in

[0033] When the valve plug 10 is fitted in the vertical hole section 201, the inflow port 202a can be provided on the upper side of the column base 1. In the illustrated embodiment, the cylinder hole 201 may further have an enlarged hole section 201c connected to the upper side of the vertical hole section 201. The aperture size of the enlarged hole section 201c is slightly larger than that of the vertical hole section 201, and the inflow port 202a can be provided in the enlarged hole section 201c. This can reduce the length of the vertical hole section 201 that needs to be finely machined.

[0034] See Figure 3, the outlet 202b can be provided on the hole wall 201a of the vertical hole section 201. As the valve plug 10 moves up and down relative to the valve cylinder 20, the area of the outlet 202b blocked by the outer cylindrical surface 11 of the column platform 1 gradually changes, thereby adjusting the flow rate of the fluid flowing out of the outlet 202b. In one embodiment, the outlet 202b may include a plurality of small holes arranged in multiple rows up and down. When the valve plug 10 moves up and down relative to the valve cylinder 20, different numbers of holes are blocked, thereby adjusting the flow rate. This is also a form in which the area of the outlet 202b blocked by the outer cylindrical surface 11 of the column platform 1 gradually changes.

[0035] The transverse dimension of the column platform 1 gradually decreases from the upper column end 14 that is in clearance fit with the vertical hole section 201 towards the lower column end 15. Compared with the case where the transverse dimension remains unchanged, as the valve plug 10 moves up and down relative to the valve cylinder 20, while the area of the outlet 202b blocked by the outer cylindrical surface 11 of the column platform 1 gradually changes, the transverse gap between the outlet 202b and the outer cylindrical surface 11 also gradually changes, which can increase the sensitivity of adjusting the flow rate of the fluid flowing out of the outlet 202b.

[0036] In the illustrated embodiment, the outer cylindrical surface 11 of the column platform 1 is preferably a conical surface. Correspondingly, the vertical hole section 201 of the cylinder hole 200 of the valve cylinder 20 is a straight circular hole. Since the conical surface forming the outer cylindrical surface 11 gradually tapers from top to bottom, it can also be called an inverted conical surface. The outer cylindrical surface 11 of the column platform 1 can be processed by an inverted taper grinding process. In the inverted taper grinding process, a cylindrical bar can be rotated along the central axis, and the cylindrical bar can be ground by a grinding head provided on the side of the cylindrical bar. At the same time, the grinding head feeds along the feed direction intersecting with the central axis, and thus the column platform 1 with the outer cylindrical surface 11 being a conical surface can be obtained.

[0037] In a preferred embodiment, the taper r1 of the conical surface forming the outer cylindrical surface 11 can be 1:20 to 1:100. The taper r1 of the conical surface = l1 / l2. As Figure 3 shown, where l1 is the thickness of the column platform 1, and l2 is half of the value obtained by subtracting the diameter D15 of the column platform 1 at its lower column end 15 from the diameter D14 of the column platform 1 at its upper column end 14, that is, the difference between the radius of the column platform 1 at its upper column end 14 and the radius of the column platform 1 at its lower column end 15. The clearance fit between the upper column end 14 of the column platform 1 and the vertical hole section 201 can be controlled at h4 / G5, for example.

[0038] The setting range of the above-mentioned taper r1 can meet the design requirements. When the taper is relatively large, the gap between the lower end of the outer cylindrical surface 11 of the valve plug and the vertical hole section 201 of the cylinder hole 200 of the valve cylinder 20 will be relatively large, which cannot meet the sealing requirements between the valve plug and the valve cylinder and the dimensional tolerance requirements of the valve plug; when the taper is relatively small, the problem of fuel impurities accumulating in the gap between the valve plug and the valve cylinder cannot be solved. Through processing and testing, it is found that when the taper > 1:10, the lower end of the outer cylindrical surface 11 of the valve plug can no longer meet the dimensional requirements, and when the taper < 1:150, the problem of fuel impurities accumulating at this position cannot be solved. After the valve works for more than 3.5 hours, the change in the valve hysteresis rate has exceeded 5%, which cannot meet the design requirements. Through experimental verification, designing the taper here to be 1:20 to 1:100 can ensure the sealing performance and the sewage discharge function.

[0039] In the illustrated embodiment, the valve plug 10 may further include a boss 2 and a cover platform 3.

[0040] The boss 2 may be connected below the column platform 1 through a journal section 42 and is arranged to be also adaptable in the vertical hole section 201. That is, the column platform 1 and the boss 2 of the valve plug 10 may both be adaptable in the vertical hole section 201 of the cylinder hole 200 of the valve cylinder 20. In the illustrated embodiment, the outer peripheral surface 21 of the boss 2 may be a straight cylindrical surface, and the diameter of this straight cylindrical surface (that is, the diameter D2 of the boss 2) is set to allow the boss 2 to be adaptable in the vertical hole section 201 of the cylinder hole 200 of the valve cylinder 20. For example, the maximum diameter of the column platform 1 (that is, the diameter D14 of the column platform 1 at its upper column end 14) and the diameter D2 of the boss 2 may be the same. It should be understood that a certain manufacturing error is allowed for the description of the same dimensions in the text. For example, a difference within 0.01 mm is allowed.

[0041] The outer peripheral surface 21 of the boss 2 may be provided with a drainage groove 22 extending vertically and recessing inward. The upper end side P224 of the drainage groove 22 is open, while the lower end side P225 of the drainage groove 22 is closed.

[0042] The cover platform 3 is connected to the lower side of the boss 2 and is used to block the vertical hole section 201 from the lower side. The lower end side P225 of the drainage groove 22 is closed on the upper side of the cover platform 3. That is, the transverse dimension of the cover platform 3 is larger than the transverse dimension of the boss 2 and larger than the aperture dimension of the vertical hole section 201, so that the vertical hole section 201 can be blocked from the lower side. In the illustrated embodiment, the boss 2, the cover platform 3, and the column platform 1 are all in the form of column-shaped platforms.

[0043] In the valve assembly 100, as described above, the boss 2 of the valve plug 10 is adaptable in the vertical hole section 201 of the valve cylinder 20. As the valve plug 10 moves up and down relative to the valve cylinder 20, the area of the notch 220 of the drainage groove 22 exposed below the vertical hole section 201 gradually changes, thereby adjusting the fluid flow rate discharged from the drainage groove 22.

[0044] In the above valve assembly 100, the space in the cylinder bore 200 of the valve cylinder 20 is divided into upper and lower chambers S4 and S5 by the column platform 1 of the valve plug 10. Fluids such as fuel enter the upper chamber S4 in the cylinder bore 200 from the outside of the valve cylinder 20 via the inflow port 202a, then enter the lower chamber S5 via the through hole 12 of the column platform 1. By the valve plug 10 sliding up and down in the vertical hole section 201 of the cylinder bore 200 of the valve cylinder 20, the drain groove 22 can be switched between a state where it is blocked by the hole wall 201a of the vertical hole section 201 and a state where the notch 220 is exposed, and the area of the exposed notch 220 can be changed. Thus, the flow rate of the fluid flowing out from the drain groove 22 can be controlled.

[0045] By using the above valve plug 10, it can cooperate with the valve cylinder 20 to form a structure with one inlet (inflow port 202a) and two outlets (outflow port 202b and drain groove 22). Moreover, the valve plug 10 moves up and down, and the flow rates of the two outlets can be adjusted simultaneously. The above valve assembly 100 is particularly suitable for a gas turbine fuel nozzle.

[0046] The present invention also provides a gas turbine fuel nozzle, which has the above valve assembly 100, and the outflow port 202b or the drain groove 22 of the valve assembly 100 leads to the main combustion stage or the pre-combustion stage of the combustion chamber. When the valve assembly 100 has both the outflow port 202b and the drain groove 22, the outflow port 202b can lead to the first of the main combustion stage and the pre-combustion stage, and the drain groove 22 correspondingly leads to the second of the main combustion stage and the pre-combustion stage.

[0047] In the illustrated embodiment, the valve plug 10 may further include a column shaft 41, and the column shaft 41 is connected to the upper side of the column platform 1. The column shaft 41, the column platform 1, the journal section 42, the convex platform 2, and the cover platform 3 may be integral, for example, machined from the same bar. They are separated in the figure and in the description only for the sake of clear description.

[0048] In one embodiment, the cross-sectional area of the drain groove 22 varies along the groove length direction D22. Figure 2Among them, it varies along the up-and-down direction. The cross-section of the drainage groove 22 is the section of the drainage groove 22 perpendicular to the groove length direction D22. The rate of change of the flow rate of the fluid flowing out of the drainage groove 22 when the valve plug 10 slides up and down in the cylinder bore 200 can be flexibly controlled by the change of the cross-sectional area of the drainage groove 22 along the groove length direction D22. For example, the cross-sectional area of the drainage groove 22 can gradually increase from bottom to top. In this way, when the valve plug 10 slides downward along the cylinder bore 200, the flow rate of the fluid flowing out of the drainage groove 22 can increase more quickly. In another embodiment, the notch width of the drainage groove 22 can vary along the groove length direction D22, which is also beneficial to flexibly controlling the rate of change of the flow rate of the fluid flowing out of the drainage groove 22 when the valve plug 10 slides up and down. The drainage groove 22 can be in the form of a rectangular groove with a rectangular cross-section, for example.

[0049] It can be understood that specific terms are used in the text to describe the embodiments of the present invention. For example, "one embodiment", "another embodiment", and / or "yet another embodiment" mean a certain feature, structure, or characteristic related to at least one embodiment of the present invention. Therefore, it should be emphasized and noted that "one embodiment" or "another embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present invention can be appropriately combined.

[0050] In one embodiment, the outer peripheral surface 21 of the boss 2 is provided with a plurality of drainage grooves 22 distributed along the circumferential direction C0 and having different groove lengths. For example, the plurality of drainage grooves 22 can be evenly distributed along the circumferential direction C0 and have different groove length dimensions. In this way, when the valve plug 10 slides up and down to different positions, the number of drainage grooves 22 exposed by the notch 220 may change, and thus the rate of change of the flow rate of the fluid flowing out of the drainage groove 22 when the valve plug 10 slides up and down can be controlled more flexibly.

[0051] In the illustrated embodiment, the valve cylinder 20 is a cylindrical member with an open lower end and a closed upper end. The cylindrical member has a sliding hole 204 at the upper end for the column shaft 41 of the valve plug 10 to pass through and is slidably engaged with the column shaft 41. The sliding hole 204 is a through hole with chamfers B1 and B2 at both the upper and lower ends. The cylindrical hole of the cylindrical member constituting the valve cylinder 20 constitutes the cylinder bore 20, and the hole section of the cylinder bore 200 on the open lower end side constitutes the vertical hole section 201, and the bottomed hole section of the cylinder bore 201 on the closed upper end side constitutes the aforementioned enlarged hole section 202.

[0052] During actual operation, the column shaft 41 can be driven to move upward at the upper end passing through the sliding hole 204 by a driving device such as a motor, so as to drive the valve plug 10 to slide up and down.

[0053] The above valve plug 10 can be processed by the following steps: material preparation - rough turning of the outer circle - rough turning of the process table - finish turning of the outer circle - quenching - lapping of the center hole - rough grinding of the outer circle - electric machining of the round hole - electric machining of the rectangular groove - finish grinding of the outer circle - finish grinding of the mating surface by the inverted cone grinding process - wire cutting of the process table - grinding of the process table - inspection.

[0054] By using the valve plug in the above tapered form, the above-mentioned valve plug processing process of all mechanical processing can be adopted, so there is no need for manual lapping, which can improve the processing or production efficiency, and at the same time improve the consistency and qualification rate of the parts. Moreover, by using the inverted cone grinding process to provide the column platform in the form of a conical surface, the problem that fuel impurities accumulate in the gap between the valve plug and the valve cylinder during the long-term operation of the valve assembly, resulting in an increase in the hysteresis rate of the valve assembly, can be solved, and the working stability of the valve assembly can be improved.

[0055] Although the present invention is disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and decoration made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A valve plug for fitting into a cylinder bore of a valve cylinder having a vertical hole section, characterized in that, the valve plug includes a column platform which has a through hole penetrating up and down for fluid to flow from the upper side to the lower side of the column platform, and the upper column end of the column platform is arranged to have a clearance fit with the vertical hole section, and the lateral dimension of the column platform gradually decreases from the upper column end to the lower column end, so that the fitting clearance between the valve plug and the valve cylinder continuously increases.

2. The valve plug according to claim 1, characterized in that, the outer column surface of the column platform is a conical surface.

3. The valve plug according to claim 2, characterized in that, the taper of the conical surface is 1:20 to 1:

100.

4. The valve plug according to claim 1, characterized in that, the valve plug further includes: a convex platform which is connected below the column platform through a journal section and is arranged to be fitted into the vertical hole section, and the outer peripheral surface of the convex platform is provided with a drainage groove extending up and down and recessed inwardly, and the upper end side of the drainage groove is open; and a cover platform which is connected to the lower side of the convex platform for plugging the vertical hole section from the lower side, and the lower end side of the drainage groove is closed on the upper side of the cover platform.

5. A valve assembly comprising a valve cylinder and a valve plug, the cylinder bore of the valve cylinder having a vertical hole section, characterized in that, the valve plug includes a column platform which has a through hole penetrating up and down for fluid to flow from the upper side to the lower side of the column platform, and the upper column end of the column platform has a clearance fit with the vertical hole section, and the lateral dimension of the column platform gradually decreases from the upper column end to the lower column end, so that the fitting clearance between the valve plug and the valve cylinder continuously increases, whereby the valve plug is fitted into the vertical hole section.

6. The valve assembly according to claim 5, characterized in that, the outer column surface of the column platform is a conical surface.

7. The valve assembly according to claim 6, characterized in that, the taper of the conical surface is 1:20 to 1:

100.

8. The valve assembly according to claim 5, characterized in that, the cylinder bore of the valve cylinder is provided with an inlet for introducing the fluid and an outlet for discharging the fluid, and the inlet is arranged on the upper side of the column platform; the outlet is arranged on the hole wall of the vertical hole section, and as the valve plug moves up and down relative to the valve cylinder, the area of the outlet blocked by the outer column surface of the column platform gradually changes, thereby adjusting the fluid flow rate flowing out from the outlet.

9. The valve assembly according to claim 5, characterized in that, the valve plug further includes: a convex platform which is connected below the column platform through a journal section and is fitted into the vertical hole section, and the outer peripheral surface of the convex platform is provided with a drainage groove extending up and down and recessed inwardly, and the upper end side of the drainage groove is open; and a cover platform which is connected to the lower side of the convex platform for plugging the vertical hole section from the lower side, and the lower end side of the drainage groove is closed on the upper side of the cover platform, and as the valve plug moves up and down relative to the valve cylinder, the area of the notch of the drainage groove exposed below the vertical hole section gradually changes, thereby adjusting the fluid flow rate discharged from the drainage groove.

10. A gas turbine fuel nozzle, characterized in that, Having a valve assembly as described in any one of claims 5 to 9, an outflow port or a drainage groove of the valve assembly leads to a main combustion stage or a pre-combustion stage of a combustion chamber.

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