A full bore linear electrically actuated throttling valve

Abstract

A full-bore linear electric throttle valve relates to the technical field of throttle valves, which comprises a valve body, a full-bore linear valve core, a valve rod, an electric actuator, an inflow flange, the electric actuator is arranged on one side of the valve body, the outflow flange is arranged on the other side of the valve body, the full-bore linear valve core is coaxially arranged in the axial through hole of the valve body, the side wall of the full-bore linear valve core is provided with a gradually-changing throttling channel and a full-bore inflow flow channel, the valve rod is connected with the full-bore linear valve core and the electric actuator respectively, the inflow flange is radially arranged on the side surface of the valve body, the full-bore linear valve core can axially move under the drive of the electric actuator and the valve rod, so that the flow channel of the inflow flange and the outflow flange is in communication or cut off; the gradually-changing throttling channel and the full-bore inflow flow channel adopt the gradually-expanding structure design from outside to inside, the speed of fluid gradually decreases and the pressure gradually increases when the fluid flows in the flow channel, the deposition and blockage of solid-phase particles in the flow channel are effectively avoided, and the full-bore linear electric throttle valve is suitable for the drilling fluid working condition with high solid-phase content.

Description

Technical Field

[0001] This invention relates to the field of throttle valve technology, and more specifically to a full-bore linear electric throttle valve. Background Technology

[0002] As my country's ultra-deep oil and gas exploration and development continues to advance to depths of 6,000 meters and even 8,000 meters and above, well control safety faces unprecedented challenges. The choke and kill manifold, as a key piece of equipment for maintaining well pressure balance and preventing blowouts, has its core component, the choke valve, whose performance directly affects the safety and controllability of drilling operations. In the complex conditions of ultra-deep and extra-deep wells, the choke valve needs to achieve precise pressure regulation and stable flow control in high-pressure, high-solids-content, and multiphase flow environments. This places extremely high demands on the valve core structure's flow capacity, anti-clogging performance, and choke characteristics.

[0003] In existing technologies, throttle valves mostly adopt a wedge-shaped valve core structure. Although they have a certain adjustment capability under conventional well depth conditions, they reveal the following significant drawbacks in ultra-deep well applications: First, insufficient flow capacity. The narrow and discontinuous flow channel design of the wedge-shaped valve core structure results in significant local resistance losses as the fluid passes through the valve core, reducing the overall flow capacity of the valve. In drilling operations requiring high-flow-rate circulation, this structure significantly increases pump pressure, impacting drilling efficiency.

[0004] Second, it has poor anti-clogging performance. The narrow flow channels of the wedge-shaped valve core are easily clogged by large debris (such as rubber fragments, rock cuttings, or plugging materials) in the drilling fluid, leading to valve failure. In ultra-deep well drilling, the bottom hole temperature is high, the pressure is high, the formation conditions are complex, and the drilling fluid often contains a large number of solid particles, making the clogging problem particularly prominent.

[0005] Third, the throttling characteristics are nonlinear. The existing wedge valve core exhibits a strongly nonlinear relationship between throttling pressure drop and opening degree, making it difficult to achieve precise control of wellhead back pressure in the small opening region, severely impacting well control response accuracy. This nonlinear characteristic makes it difficult for operators to accurately predict and control wellhead pressure, increasing well control risks.

[0006] Several improvements have been made in the prior art. For example, CN10489027A discloses a plunger-type throttle valve, which improves flow capacity by optimizing the valve core sleeve structure; CN111059298A discloses a vibration-resistant throttle valve, which improves vibration resistance by improving the valve core structure. However, none of the above solutions fundamentally solve the problem of large particle blockage, nor do they achieve linear throttling characteristics across the entire stroke range.

[0007] Therefore, there is an urgent need to develop a new type of valve core structure that combines anti-clogging function and linear throttling characteristics. This structure can ensure that the throttling pressure drop changes stably and linearly with the valve core displacement under extreme conditions of ultra-high pressure and high solid content. At the same time, it can effectively avoid the risk of clogging by optimizing the flow channel geometry, thereby providing a reliable guarantee for safe and efficient drilling of ultra-deep and extra-deep wells. Summary of the Invention

[0008] In view of this, the present invention proposes a full-bore linear electric throttle valve, including a unique full-bore linear valve core structure and a gradually changing throttle channel design, to achieve linear throttle characteristics throughout the entire stroke range, while effectively reducing the risk of solid particle blockage.

[0009] To solve at least one of the above-mentioned technical problems, the present invention provides a full-bore linear electric throttle valve, comprising: This includes the valve body, full-bore linear valve core, valve stem, electric actuator, and inlet flange, among which... The valve body is a cylindrical structure with a flow-out flange on one side, and a union cap and an electric actuator are detachably connected to the other side in sequence. A full-bore linear valve core is coaxially arranged in the axial through hole of the valve body. The full-bore linear valve core is detachably connected to a valve stem that is coaxially arranged inside the axial through hole of the valve body. The valve stem passes through the union cap and is connected to the electric actuator. The inlet flange is radially arranged on the side surface of the valve body. The full-bore linear valve core can move axially under the drive of the electric actuator and the valve stem, so that the flow channels of the inlet flange and the outlet flange are connected or cut off. The full-bore linear valve core includes a full-bore outflow channel, a locating pin hole, a connecting T-slot, a gradually changing throttling channel, and a full-bore inflow channel. The locating pin hole and the connecting T-slot are located on the same side of the full-bore linear valve core and are used to cooperate with the valve stem for fixation. The bottom surface of the full-bore linear valve core on the opposite side is provided with a full-bore outflow channel to maintain communication with the outflow flange. The gradually changing throttling channel and the full-bore incoming flow channel are set on the side wall of the full-bore linear valve core. The full-bore incoming flow channel is a circular hole structure, and the gradually changing throttling channel is a symmetrical continuous variable diameter hole structure with one side contracting and the other side expanding. The expanding side of the gradually changing throttling channel extends to be tangent to the edge of the full-bore incoming flow channel. Both the gradually changing throttling channel and the full-bore incoming flow channel can be connected to the full-bore outgoing flow channel. The gradually changing throttling channel and the full-bore incoming flow channel can be moved to be directly connected to the flow channel of the incoming flow flange.

[0010] One embodiment of the present invention is that the edge line of the gradient throttling channel satisfies the following formula: In the formula, L represents the cutting width; h represents the cutting height; ~ Let represent the coefficients of the k-th term in the formula.

[0011] Furthermore, the formula satisfied by the edge line of the gradual throttling channel is obtained by fitting a high-order polynomial curve to the cutting width L and cutting height h corresponding to the discrete point in the displacement coordinate. The method for obtaining this formula includes the following steps: Step S1: Determine the design requirements parameters of the valve core based on the application conditions of the valve core. The design requirements parameters include the full bore dimension of the valve core, the length of the valve core, the outer diameter of the valve core, the working pressure rating, the working fluid density, the target maximum pressure drop, the valve core displacement range, and the pressure drop range. Step S2: Establish a parameterized ensemble model of the full-bore linear valve core and determine the distribution of discrete points on the valve core surface. The specific method is as follows: S21: A tangent plane is provided on the surface of the full-bore linear valve core on the side away from the connecting T-slot. And specify a point O on the plane, and use point O as the center to draw a semicircle with the convex side of the arc pointing to the side of the T-slot; S22: Place the semicircle in the tangent plane Point A is the intersection of the radius parallel to the axis of the full-bore linear valve core and its arc edge. Discrete points are set at certain intervals along the OA direction. The first discrete point is denoted as A1, the second discrete point as A2, and so on. The position of point A1 coincides with point O. Step S3: Based on the relationship between throttling pressure drop and theoretical throttling flow area, the valve core displacement range and the maximum pressure drop range are linearly discretized to obtain the linear relationship between throttling pressure drop and valve core displacement within the effective stroke, and the theoretical throttling flow area corresponding to each discrete point is calculated. The relationship between the throttling pressure drop and the theoretical throttling flow area is shown in the following formula: In the formula, Indicates throttling pressure drop; Indicates the working fluid volume flow rate; The pipe cross-sectional area of ​​the valve body; Indicates the theoretical flow-throttling area; Indicates the density of the fluid under operating conditions; Step S4: Based on the theoretical throttling flow area corresponding to each discrete point, calculate the cutting width L and cutting height h corresponding to each discrete point; The relationship between the theoretical throttling flow area and the cutting width L is shown in the following formula: In the formula, R represents the outer diameter of the valve core; L represents the cutting width; and h represents the cutting height. Step S5: Using point O as the origin of the coordinate system, transform the cutting width L and cutting height h corresponding to each discrete point into coordinate points on the coordinate system and perform high-order polynomial curve fitting to obtain the high-order function equation satisfied by the edge line of the gradual throttling channel.

[0012] Furthermore, the straight line length between the OAs is 5.55 mm, the straight line distance between adjacent discrete points is 1 mm, and the number of discrete points is 60.

[0013] Furthermore, the edge line of the gradient throttling channel is fitted using a sixth-order polynomial.

[0014] In one embodiment of the present invention, the inner diameters of the full-bore outflow channel and the full-bore inflow channel are equal to the inner diameters of the inflow flange and the outflow flange.

[0015] In one embodiment of the present invention, a lower alloy bushing, an upper alloy bushing, a valve core sleeve, and a central hub are sequentially fitted onto the inner wall of the axial through hole of the valve body, starting from the side away from the union cap. The central hub extends to the outside of the union cap. A full-bore linear valve core is disposed in the valve core sleeve, which is a tubular structure with a circular hole on its side equal to the diameter of the incoming flow channel. The circular hole is equal to and aligned with the diameter of the incoming flow flange through hole.

[0016] Furthermore, the outer diameter of the full-bore linear valve core is 0.2mm to 0.4mm smaller than the inner diameter of the valve core sleeve.

[0017] Furthermore, a combined seal is provided between the central hub and the union cap. The combined seal is limited by a packing gland detachably installed on the central hub. The valve stem passes through the packing gland and the combined seal respectively, and the combined seal seals the gap between the central hub and the valve stem.

[0018] Furthermore, a bearing bracket connected to both the central hub and the electric actuator can be detachably provided. The bearing bracket contains a thrust bearing assembly, and both the bearing bracket and the thrust bearing assembly are sleeved on the valve stem.

[0019] The technical effects achieved by this invention are: (1) The full-bore linear valve core of the present invention adopts a full-bore outflow channel and a full-bore inflow channel design. Its inner diameter is equal to the inner diameter of the valve body flange, which eliminates the narrow flow channel bottleneck of the traditional wedge valve core, significantly improves the flow capacity of the valve, and reduces fluid resistance loss.

[0020] (2) The gradual throttling channel and full-bore inflow channel of the present invention adopt a gradually expanding structure design from the outside to the inside. When the fluid flows in the channel, the velocity gradually decreases and the pressure gradually increases, which effectively avoids the deposition and blockage of solid particles in the channel. It is particularly suitable for drilling fluid with high solid content.

[0021] (3) The present invention uses a parametric design method to precisely design the geometry of the gradual throttling channel, so that the throttling pressure drop changes linearly with the valve core displacement. Operators can accurately predict and control the wellhead pressure, significantly improving the well control response accuracy and safety.

[0022] (4) The full-bore linear valve core and valve core sleeve of the present invention adopt a precision fit clearance of 0.2mm~0.4mm, which ensures that the valve core can move smoothly and ensures good sealing performance, and is suitable for high pressure conditions.

[0023] (5) The components such as the central hub and bearing bracket in this invention adopt a threaded connection method, which facilitates installation, disassembly and maintenance, and reduces maintenance costs and downtime. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the full-bore linear electric throttle valve in this invention; Figure 2 This is a schematic diagram of the full-bore linear valve core structure in this invention; Figure 3 This is a schematic diagram of the valve core sleeve in this invention; Figure 4 This is a schematic diagram showing the distribution of discrete points on the tangent plane of the full-bore linear valve core surface in this invention; Figure 5 This is a curve showing the relationship between the throttling opening and the throttling pressure drop of a conventional wedge-shaped throttling valve in the performance evaluation of this invention. Figure 6 The curve showing the relationship between the throttling opening and the throttling pressure drop of the full-bore linear valve core proposed in this invention; Figure 7 This is a schematic diagram showing the position of the tangent plane on the surface of the full-bore linear valve core in this invention; In the diagram: 1-Valve body, 2-Lower alloy bushing, 3-Upper alloy bushing, 4-Full-bore linear valve core, 4-1-Full-bore outflow channel, 4-2-Positioning pin hole, 4-3-Connecting T-slot, 4-4-Gradual throttling channel, 4-5-Full-bore inflow channel, 5-Valve core sleeve, 5-1-Round hole, 6-Central hub, 7-Valve stem, 8-Union cap, 9-Electric actuator, 10-Bearing bracket, 11-Thrust bearing assembly, 12-Packaging gland, 13-Combination seal, 14-Inflow flange, O-Semicircle center, A-Intersection of the semicircle and its arc edge. Tangent plane on the surface of the full-bore linear valve core, A1 - first discrete point, A2 - second discrete point, A60 - sixtieth discrete point, L - cutting width, h - cutting height. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0028] Example: See Figure 1 A full-bore linear electric throttle valve, comprising: Valve body 1, full-bore linear valve core 4, valve stem 7, electric actuator 9, inlet flange 14, wherein, The valve body 1 is a cylindrical structure with a flow-out flange on one side, and a union cap 8 and an electric actuator 9 are detachably connected to the other side in sequence. The electric actuator 9 can refer to the valve body drive structure in the prior art. A full-bore linear valve core 4 is coaxially arranged in the axial through hole of the valve body 1. The full-bore linear valve core 4 is detachably connected to the valve stem 7, which is coaxially arranged inside the axial through hole of the valve body 1. The valve stem 7 passes through the union cap 8 and is connected to the electric actuator 9. The inlet flange 14 is radially arranged on the side surface of the valve body 1. The full-bore linear valve core 4 can move axially under the drive of the electric actuator 9 and the valve stem 7, so that the flow channels of the inlet flange 14 and the flow-out flange are connected or cut off. The valve body 1 is an integral structure with an axial through hole. Flange interfaces are provided at both ends of the through hole for connection to the inlet and outlet pipes, respectively. The valve body 1 can be made of high-strength alloy steel, capable of withstanding the high pressure under ultra-deep well conditions.

[0029] The inner wall of the axial through hole of the valve body 1 is sequentially fitted with a lower alloy bushing 2, an upper alloy bushing 3, a valve core sleeve 5, and a central hub 6, starting from the side away from the union cap 8. The central hub 6 extends to the outside of the union cap 8, and the full-bore linear valve core 4 is disposed in the valve core sleeve 5.

[0030] The lower alloy bushing 2 and the upper alloy bushing 3 are respectively installed in the axial through hole of the valve body 1. They are made of wear-resistant alloy material and are used to protect the inner surface of the valve body 1 and extend the service life of the valve. The inner diameters of the lower alloy bushing 2, the upper alloy bushing 3 and the valve core sleeve 5 are equal, forming a flow channel of equal diameter to ensure smooth fluid flow in the valve.

[0031] See Figure 3 The valve core sleeve 5 is located in the axial through hole of the valve body 1, between the lower alloy bushing 2 and the upper alloy bushing 3. The valve core sleeve 5 is a tubular structure, and its side is provided with a circular hole 5-1 with the same diameter as the incoming flow channel 4-5. The circular hole 5-1 is equal to and aligned with the diameter of the through hole of the incoming flow flange 14, forming a channel for fluid to enter the inner cavity of the valve core sleeve 5.

[0032] In this embodiment, the outer diameter of the full-bore linear valve core 4 is 0.2mm~0.4mm smaller than the inner diameter of the valve core sleeve 5, and the outer diameter of the full-bore linear valve core 4 is 0.2-0.4mm smaller than the inner diameter of the valve core sleeve 5, forming a precision fit clearance. This clearance range ensures that the valve core can move smoothly within the valve core sleeve 5 while also ensuring good sealing performance. Preferably, the fit clearance is 0.3mm.

[0033] In this embodiment, a combined seal 13 is provided between the central hub 6 and the union cap 8. The combined seal 13 is limited by a packing gland 12 that is detachably provided on the central hub 6. The valve stem 7 passes through the packing gland 12 and the combined seal 13 respectively. The combined seal 13 seals the gap between the central hub 6 and the valve stem 7. The combined seal 13 is limited by the packing gland 12 to ensure the sealing performance between the valve stem 7 and the central hub 6.

[0034] In this embodiment, a bearing bracket 10 connected to the central hub 6 and the electric actuator 9 can be detachably provided. The bearing bracket 10 is provided with a thrust bearing assembly 11 inside. Both the bearing bracket 10 and the thrust bearing assembly 11 are sleeved on the valve stem 7.

[0035] The valve stem 7 is connected to the full-bore linear valve core 4 via a T-slot 4-3, transmitting the driving force of the electric actuator 9. The electric actuator 9 is connected to the bearing bracket 10 via a flange. The bearing bracket 10 contains a thrust bearing assembly 11 to withstand the axial thrust of the full-bore linear valve core 4 under high differential pressure conditions. The bearing bracket 10 can be threaded to the central hub 6 for easy installation and maintenance.

[0036] like Figure 2 As shown, the full-bore linear valve core 4 includes a full-bore outflow channel 4-1, a positioning pin hole 4-2, a connecting T-slot 4-3, a gradual throttling channel 4-4, and a full-bore inflow channel 4-5. The positioning pin hole 4-2 and the connecting T-slot 4-3 are located on the same side of the full-bore linear valve core 4 and are used to cooperate with the valve stem 7 for fixation. The bottom surface of the full-bore linear valve core 4 on the opposite side is provided with a full-bore outflow channel 4-1 to maintain communication with the outflow flange.

[0037] The gradually changing throttling channel 4-4 and the full-bore incoming flow channel 4-5 are disposed on the side wall of the full-bore linear valve core 4. The full-bore incoming flow channel 4-5 is a circular hole structure, and the gradually changing throttling channel 4-4 is a symmetrical continuous variable diameter hole structure with one side contracting and the other side expanding. The expanding side of the gradually changing throttling channel 4-4 extends to be tangent to the edge of the full-bore incoming flow channel 4-5. Both the gradually changing throttling channel 4-4 and the full-bore incoming flow channel 4-5 can be connected to the full-bore outgoing flow channel 4-1. The gradually changing throttling channel 4-4 and the full-bore incoming flow channel 4-5 can be moved to be directly connected to the flow channel of the incoming flow flange 14.

[0038] The gradual throttling channel 4-4 extends axially along the valve core and connects with the full-bore inflow channel 4-5. Both the gradual throttling channel 4-4 and the full-bore inflow channel 4-5 employ a gradually expanding structure design from the outside in, meaning the cross-section of the flow channel gradually increases from the outer surface of the valve core inwards. This gradually expanding structure design causes the fluid velocity to gradually decrease and the pressure to gradually increase as it flows within the channel, effectively preventing the deposition and blockage of solid particles within the channel.

[0039] The edge line of the gradual throttling channel 4-4 satisfies the following formula: In the formula, L represents the cutting width; h represents the cutting height; ~ Let represent the coefficients of the k-th term in the formula.

[0040] Among them, see Figure 4 The formula satisfied by the edge line of the gradual throttling channel 4-4 is obtained by fitting a high-order polynomial curve to the cutting width L and cutting height h corresponding to the discrete points in the displacement coordinate. The least squares method is preferred for fitting, and the method includes the following steps: Step S1: Based on the application conditions of the valve core, determine the design requirements parameters of the valve core. These parameters include the full bore size of the valve core, valve core length, valve core outer diameter, operating pressure rating, operating fluid density, target maximum pressure drop, valve core displacement range, and throttling pressure drop range. Taking a throttling valve for an ultra-deep well as an example, the full bore size of the valve core is 78mm, the valve core length is 200mm, the operating pressure rating is 140MPa, the operating fluid density is 1500kg / m³, and the target maximum pressure drop is 60MPa.

[0041] Step S2: Establish a parameterized ensemble model of the full-bore linear valve core 4 to determine the distribution of discrete points on the valve core surface. The specific method is as follows: S21: As Figure 7 As shown, a tangent plane is provided on the surface of the full-bore linear valve core 4 on the side away from the connecting T-slot 4-3. And specify a point O on the plane, and further in Figure 4 As can be seen above, with point O as the center, an arc edge is drawn with the convex side pointing towards the semicircle connecting the T-slot 4-3 on one side; S22: Place the semicircle in the tangent plane Point A is the intersection of the radius parallel to the axis of the full-bore linear valve core 4 and its arc edge. Discrete points are set at certain intervals along the OA direction. The first discrete point is denoted as A1, the second discrete point as A2, and so on. The position of point A1 coincides with point O. In this embodiment, the straight line length between OA is 5.55mm, the straight line distance between adjacent discrete points is 1mm, and the number of discrete points is 60, that is, the final discrete point can be determined up to A60.

[0042] Step S3: Based on the relationship between throttling pressure drop and theoretical throttling flow area, the valve core displacement range and the maximum pressure drop range are linearly discretized to obtain the linear relationship between throttling pressure drop and valve core displacement within the effective stroke, and the theoretical throttling flow area corresponding to each discrete point is calculated. In this embodiment, the valve core displacement range is 0mm~200mm, and the throttling pressure drop ΔP range is 0MPa~70MPa.

[0043] A mathematical model of throttling pressure drop is established based on Bernoulli's equation and continuity equation in fluid mechanics, and the functional relationship between throttling pressure drop and theoretical throttling flow area is derived.

[0044] The relationship between the throttling pressure drop and the theoretical throttling flow area is shown in the following formula: In the formula, Indicates throttling pressure drop; Indicates the working fluid volume flow rate; The pipe cross-sectional area of ​​the valve body; Indicates the theoretical flow-throttling area; Indicates the density of the fluid under operating conditions; Step S4: Based on the theoretical throttling flow area corresponding to each discrete point, calculate the cutting width L and cutting height h corresponding to each discrete point; A parametric geometric model of the full-bore linear valve core 4 body was constructed in 3D design software. The core design variables were set as follows: valve core outer diameter D=103mm and full bore d=78mm. The theoretical throttling flow area was also established. The geometric correlation equation between the gradient throttling channel 4-4 and the cutting width L.

[0045] The relationship between the theoretical throttling flow area and the cutting width L is shown in the following formula: In the formula, R represents the outer diameter of the valve core; L represents the cutting width; and h represents the cutting height. This is a transcendental equation for the area of ​​a triangle-like structure. Existing techniques can be referenced, and numerical calculation methods (such as Newton's iteration method) can be used to calculate the theoretical throttling flow area corresponding to each discrete point. Solve for the corresponding cutting width L.

[0046] Step S5: Using point O as the origin of the coordinate system, transform the cutting width L and cutting height h corresponding to each discrete point into coordinate points on the coordinate system, and perform high-order polynomial curve fitting. Here, we combine... Figure 4 As can be seen, the geometric meaning of the cutting height h corresponding to each discrete point is the distance from point O to that discrete point. y The distance on the axis, and the geometric meaning of the cutting width L corresponding to each discrete point is the distance from point O to the higher-order polynomial curve point corresponding to the discrete point. x Axial distance, within the theoretical throttling flow area After obtaining the cutting width L at each discrete point, a higher-order polynomial curve can be fitted, ultimately yielding the higher-order function equation satisfied by the edge line of the gradient throttling channel 4-4. In this embodiment, a sixth-order polynomial is preferably used for fitting, and the fitting result is as follows: In coordinate system x The positive cutting edge line on the axis is denoted as L. x The positive cutting edge line on the axis is represented as -L.

[0047] Importing this equation into 3D design software such as SolidWorks or CATIA will drive the generation of a continuous and smooth gradient throttling channel 4-4, with the gradient line originating from the tangent plane. By vertically projecting the flow path onto the surface of the full-bore linear valve core 4, and cutting the corresponding flow path structure, the gradual throttling channel 4-4 structure is obtained.

[0048] Meanwhile, the expansion side of the gradient throttling channel 4-4 extends to be tangent to the edge of the full-bore incoming flow channel 4-5. In this embodiment, the inner diameters of the full-bore outgoing flow channel 4-1 and the full-bore incoming flow channel 4-5 are equal to the inner diameters of the incoming flange 14 and the outgoing flange.

[0049] Furthermore, the working principle of this invention is as follows: Drilling fluid enters from the inlet flange 14 of valve body 1, passes through the inlet flow direction through hole into the round hole 5-1 of valve core sleeve 5, then enters the gradual throttling channel 4-4 and the full-bore inlet flow channel 4-5 of full-bore linear valve core 4, and finally flows out from the full-bore outlet flow channel 4-1 and is discharged through the outlet flange of valve body 1.

[0050] When it is necessary to adjust the throttling pressure drop, the electric actuator 9 drives the full-bore linear valve core 4 to move axially within the valve core sleeve 5 via the valve stem 7. As the valve core moves, the overlap area between the gradual throttling channel 4-4 and the circular orifice 5-1 changes, thereby altering the throttling flow area and adjusting the throttling pressure drop. Because the gradual throttling channel 4-4 is precisely parametrically designed, the throttling pressure drop changes linearly with the valve core displacement, allowing operators to accurately predict and control the wellhead back pressure.

[0051] Performance evaluation: A fluid surface test was conducted using an existing well control wedge-shaped choke valve and the full-bore linear valve core proposed in this invention. The test fluid was clean water, and a fracturing pump was used to provide the fluid circulation power, with a fixed fluid flow rate of 0.6 m³ / min. 3 The displacement of the throttle valve was gradually adjusted at a rate of / min, and the throttle pressure drop at the corresponding displacement was recorded. A curve showing the relationship between the throttle displacement and the throttle pressure drop was plotted. The test results for both are shown below. Figure 5 , Figure 6 As shown.

[0052] from Figure 5 As can be seen, the throttling pressure drop of the existing well control wedge throttle valve exhibits a non-linear relationship with the opening degree, especially within the small opening range. Even small changes in opening degree cause large changes in throttling pressure drop, making it difficult to adjust the target pressure drop during field operations. Figure 6 As can be seen from the paper, the full-bore linear valve core proposed in this invention has a strong linear correlation between the throttling opening and the throttling pressure drop. During on-site construction, this makes it easier to control the wellhead back pressure, reduces well control risks, and improves the level of well control technology.

[0053] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A full-bore linear electric throttle valve, characterized in that, Includes valve body (1), full-bore linear valve core (4), valve stem (7), electric actuator (9), and inlet flange (14), wherein, The valve body (1) is a cylindrical structure with a flow-out flange on one side, and a union cap (8) and an electric actuator (9) are detachably connected to the other side in sequence. A full-bore linear valve core (4) is coaxially arranged in the axial through hole of the valve body (1). The full-bore linear valve core (4) is detachably connected to the valve stem (7) which is coaxially arranged inside the axial through hole of the valve body (1). The valve stem (7) passes through the union cap (8) and is connected to the electric actuator (9). The inlet flange (14) is radially arranged on the side surface of the valve body (1). The full-bore linear valve core (4) can move axially under the drive of the electric actuator (9) and the valve stem (7), so that the flow channels of the inlet flange (14) and the flow-out flange are connected or cut off. The full-bore linear valve core (4) includes a full-bore outflow channel (4-1), a positioning pin hole (4-2), a connecting T-slot (4-3), a gradual throttling channel (4-4), and a full-bore inflow channel (4-5). The positioning pin hole (4-2) and the connecting T-slot (4-3) are located on the same side of the full-bore linear valve core (4) and are used to cooperate with the valve stem (7) for fixation. The bottom surface of the full-bore linear valve core (4) on the opposite side is provided with a full-bore outflow channel (4-1) that maintains communication with the outflow flange. The gradually changing throttling channel (4-4) and the full-bore incoming flow channel (4-5) are set on the side wall of the full-bore linear valve core (4). The full-bore incoming flow channel (4-5) is a circular hole structure, and the gradually changing throttling channel (4-4) is a symmetrical continuous variable diameter hole structure with one side contracting and the other side expanding. The expansion side of the gradually changing throttling channel (4-4) extends to be tangent to the edge of the full-bore incoming flow channel (4-5). Both the gradually changing throttling channel (4-4) and the full-bore incoming flow channel (4-5) can be connected to the full-bore outgoing flow channel (4-1). The gradually changing throttling channel (4-4) and the full-bore incoming flow channel (4-5) can be moved to be directly connected to the flow channel of the incoming flow flange (14). The gradual throttling channel (4-4) and the full-bore inflow channel (4-5) adopt a gradually expanding structure design from the outside to the inside, that is, the cross-section of the flow channel gradually expands from the outer surface of the valve core inward. The edge line of the gradually changing throttling channel (4-4) satisfies the following formula: In the formula, L represents the cutting width; h represents the cutting height; ~ Let represent the coefficients of the k-th term in the formula; The formula satisfied by the edge line of the gradual throttling channel (4-4) is obtained by fitting a high-order polynomial curve to the cutting width L and cutting height h corresponding to the discrete points in the displacement coordinate. The method for obtaining this formula includes the following steps: Step S1: Determine the design requirements parameters of the valve core based on the application conditions of the valve core. The design requirements parameters include the full bore dimension of the valve core, the length of the valve core, the outer diameter of the valve core, the working pressure rating, the working fluid density, the target maximum pressure drop, the valve core displacement range, and the pressure drop range. Step S2: Establish a parameterized ensemble model of the full-bore linear valve core (4) and determine the distribution of discrete points on the valve core surface. The specific method is as follows: S21: A tangent plane is provided on the surface of the full-bore linear valve core (4) away from the connecting T-slot (4-3). And specify a point O on the plane, and use point O as the center to make a semicircle with the convex side of the arc pointing to the side of the T-slot (4-3); S22: Place the semicircle in the tangent plane The point where the radius parallel to the axis of the full-bore linear valve core (4) intersects with its arc edge is denoted as point A. Discrete points are set at certain intervals along the OA direction. The first discrete point is denoted as A1, the second discrete point as A2, and so on. The position of point A1 coincides with point O. Step S3: Based on the relationship between throttling pressure drop and theoretical throttling flow area, the valve core displacement range and the maximum pressure drop range are linearly discretized to obtain the linear relationship between throttling pressure drop and valve core displacement within the effective stroke, and the theoretical throttling flow area corresponding to each discrete point is calculated. The relationship between the throttling pressure drop and the theoretical throttling flow area is shown in the following formula: In the formula, Indicates throttling pressure drop; Indicates the working fluid volume flow rate; The pipe cross-sectional area of ​​the valve body; Indicates the theoretical flow-throttling area; Indicates the density of the fluid under operating conditions; Step S4: Based on the theoretical throttling flow area corresponding to each discrete point, calculate the cutting width L and cutting height h corresponding to each discrete point; The relationship between the theoretical throttling flow area and the cutting width L is shown in the following formula: In the formula, R represents the outer diameter of the valve core; L represents the cutting width; and h represents the cutting height. Step S5: Using point O as the origin of the coordinate system, transform the cutting width L and cutting height h corresponding to each discrete point into coordinate points on the coordinate system and perform high-order polynomial curve fitting to obtain the high-order function equation satisfied by the edge line of the gradual throttling channel (4-4). The straight line length between OA is 5.55 mm, the straight line distance between adjacent discrete points is 1 mm, and the number of discrete points is 60.

2. The full-bore linear electric throttle valve according to claim 1, characterized in that: The edge line of the gradient throttling channel (4-4) is fitted using a sixth-order polynomial.

3. The full-bore linear electric throttle valve according to claim 1, characterized in that: The inner diameters of the full-bore outflow channel (4-1) and the full-bore inflow channel (4-5) are equal to the inner diameters of the inflow flange (14) and the outflow flange.

4. The full-bore linear electric throttle valve according to claim 1, characterized in that: The inner wall of the axial through hole of the valve body (1) is sequentially fitted with a lower alloy bushing (2), an upper alloy bushing (3), a valve core sleeve (5), and a central hub (6) starting from the side away from the union cap (8). The central hub (6) extends to the outside of the union cap (8). The full-bore linear valve core (4) is set in the valve core sleeve (5). The valve core sleeve (5) is a tubular structure with a circular hole (5-1) on its side that is equal in diameter to the incoming flow channel (4-5). The circular hole (5-1) is equal in diameter to and aligned with the through hole of the incoming flange (14).

5. A full-bore linear electric throttle valve according to claim 4, characterized in that: The outer diameter of the full-bore linear valve core (4) is 0.2mm~0.4mm smaller than the inner diameter of the valve core sleeve (5).

6. A full-bore linear electric throttle valve according to claim 4, characterized in that: A combined seal (13) is provided between the central hub (6) and the union cap (8). The combined seal (13) is limited by a packing gland (12) that is detachably provided on the central hub (6). The valve stem (7) passes through the packing gland (12) and the combined seal (13) respectively. The combined seal (13) seals the gap between the central hub (6) and the valve stem (7).

7. A full-bore linear electric throttle valve according to claim 4, characterized in that: A bearing bracket (10) is detachably provided between the central hub (6) and the electric actuator (9) and connected to both. A thrust bearing assembly (11) is provided inside the bearing bracket (10). Both the bearing bracket (10) and the thrust bearing assembly (11) are sleeved on the valve stem (7).

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