STRUCTURE OF A FLUOROPLASTIC THROTTLE VALVE

Abstract

A design of a fluoropolymer throttle valve, comprising: a valve stem (2); and a throttle disc (5) which is rotatably attached to the valve stem (2) by means of a valve shaft (55); by a rotary rotation of the valve shaft (55) the valve stem (2) with the throttle disc (5) is opened or closed; wherein a throttle disk (5) has an outer edge of the throttle disk (53); the outer edge of the throttle disk (53) has an annularly curved surface (531); the annularly curved surface (531) has a conical surface of unequal width (532); a sealing width (63(B)) of the conical surface of unequal width (532) gradually widens from the valve shaft (55) to a central part of the throttle disk (5); a sealing width (63(B)) of a part of the conical surface of unequal width (532) near the valve shaft (55) is 50 percent (50%) greater than a thickness of an outer edge (511) of an inner metallic throttle disk (51); a sealing width (63(B)) of a part of the conical surface with unequal width (532) near the middle part of the throttle disk (5) is 70 percent (70%) greater than the thickness of the outer edge (511) of the metallic throttle disk (51).

Description

Technical area

[0001] The present invention relates to a fluoroplastic throttle valve structure, and more particularly, to a symmetrical throttle valve structure incorporating a corrosion- and temperature-resistant fluoroplastic liner. A throttle disc of the valve structure is encapsulated with an external fluoroplastic encapsulation to improve the sealing mechanism of an outer edge of the throttle disc, thereby reducing the torque required by a valve shaft, extending the life of the fluoroplastic liner, and improving the sealing resistance to pressure and temperature during closing and opening. The outer edge of the throttle disc is actuated with interference sliding during closing, achieving a tight seal in a fully closed state. Therefore, the throttle valve's specifications adapted to specific purposes can be achieved. For example: Corrosive liquid: transport liquid, such as hydrofluoric acid, hydrochloric acid and sulfuric acid. Highest temperature: for a special purpose ≦ 200° Celsius. Maximum pressure: for a special purpose ≦ 3kg@200° Celsius. State of the art

[0002] The Fig. 7A, Fig. 7B, Fig. 7C and Fig. 7D shows a prior art symmetrical fluoroplastic throttle valve 9 used for flowing fresh water and corrosive liquids at ordinary temperatures. The fluoroplastic throttle valve 9 uses a rubber with low hardness and high elasticity for the fluoroplastic with high bending ability. The valve structure consists of a valve stem 91, a throttle disc 92, a liner 93, a backup ring 94, a valve shaft 95, etc.

[0003] The valve stem 91 is formed in the shape of a ring and divided into two semicircular valve stems, i.e., an upper valve stem and a lower valve stem, which are fastened with two fasteners to unite the two-piece valve stem 91. An inner peripheral surface 911 of the valve stem 91 has a groove 912 into which a support ring 94 is inserted. The figures do not show that the inner peripheral surface 911 also allows insertion of a liner 93. An upper stem hole portion 913 and a lower stem hole portion 914 are each provided on the two-piece valve stem.

[0004] The Fig. Figure 7C shows that the backup ring 94 is made of rubber and is interposed between the annular groove 912 of the inner peripheral surface 911 and a tubular portion 931. Therefore, the backup ring 94 compensates for the insufficient elasticity of the fluoroplastic, allows for a greater degree of deformation, reduces the torque requirement, sufficiently supports an inner surface 933 of the liner during deformation, and imparts sealing capability to the outer edge 922 of the throttle plate and the inner surface 933 of the liner. The material of the backup ring 94 is temperature-resistant. The ordinary rubber can resist the temperature less than or equal to 120° Celsius (≦120°C), while the fluororubber can resist the temperature less than or equal to 180° Celsius (≦180°C) and the silicone rubber can resist the temperature less than or equal to 260° Celsius (≦260°C) (which is equivalent to 500° Fahrenheit).

[0005] The Fig. 7D shows that the liner 93 is formed with a tubular part 931, two ends of which are formed with a radial flange 932, which serves as a sealing surface for a pipe connection and reduces shrinkage and deformation due to high temperatures by supporting the valve stem 91. When the valve is closed, the outer edge 922 of the orifice plate is pressed against an inner diametrical surface of the tubular part 931, which tubular part 931 is supported by the valve stem 91 and the support ring 94. This inner diametrical surface is referred to as an inner surface 933 of the liner. Most of the tubular parts 931 are made of a thin structure, which is used for the support ring 94 to ensure sealing with the required force, thus closing the flow of the fluid and withstanding the pressure and temperature of the fluid.A horizontal sealing plane 632 is formed at each of two ends of the tubular part 931 in a diametrical direction. An inner diameter and an outer diameter of the tubular part 931 are covered by a thickness of the horizontal sealing plane 632, wherein this inner diameter and the outer diameter of the tubular part 931 each have a planar structure. A diametrical distance between the two horizontal sealing planes 632 is shorter than an inner diameter of the tubular part 931. The thickness of the sealing plane 632 is greater than a thickness of the tubular part 931. Two side edges of the sealing plane 632 and the inner diametrical surface of the lining are each attached to the joining edges 633. The joining edge 633 is formed in an arc shape, with which the structures of different thicknesses are attached.The sealing plane 632 has a stem hole surface 634 and a stem hole 937 to receive the valve shaft 95 (not shown) in order to rotate the throttle plate 92 to control the flow rate, open the valve or close the valve (not shown).

[0006] The Fig. 7C and Fig. 7D show that an inner diameter of the rubber backup ring 94 corresponds to an inner diameter of the inner peripheral surface 23 and also to the outer diameter of the tubular part 31. However, the outer diameter of the tubular part 931 protrudes inward due to shrinkage and deformation during the manufacturing process, so that the outer diameter of the tubular part 931 is slightly smaller than the inner diameter of the inner peripheral surface 911. Similarly, the inner diameter of the rubber backup ring 94 is slightly smaller than the inner diameter of the inner peripheral surface 911 due to shrinkage and deformation during the manufacturing process, in other words, the inner surface 933 of the liner protrudes inward due to the deformation, so that its inner radius is smaller after installation. The inner diameter of the inner surface 933 of the liner therefore has a round cross-section 66a with a projection 66b(h).With this design, a radius of a throttle plate flank 921 is larger than the inner radius of the inner surface 933 of the liner, and the packing quantity 65(ε) is larger. In the prior art method, when two fasteners are attached to join the two-piece valve stem 92, the valve stem 92 presses against the rubber support ring 94, and the tubular portion 931 also leaves a tolerance and packing space due to the valve stem 91.

[0007] The Fig. 7A and Fig. 7B shows that the throttle plate 92 has the shape of a disc-shaped structure. The throttle plate 92 is formed with two sides, hereinafter referred to as throttle plate flanks 921, and further has a plate-like cross-section, hereinafter referred to as the throttle plate band seal 92b. This sealing structure is referred to as the band seal 62, with the corresponding outer edge 922 of the throttle plate forming an annular curved surface 923. The throttle plate 92 has a conical cross-section, hereinafter referred to as the throttle plate of the linear seal 92a. This sealing structure is referred to as the linear seal 61, with the corresponding outer edge 922 of the throttle plate forming a conical curved surface 924. The outer diameter is slightly larger than the inner diameter of the liner 93, and the radius difference corresponds to the packing quantity 65(ε).The throttle plate 92 can receive a torque 79(T) transmitted from the valve shaft 92 to open and close the throttle valve 9. The torque 79(T) includes an initial torque for sealing the shaft, a frictional torque 794(Tf) created by a movement referred to as interference sliding 7, which allows the outer edge 922 of the throttle plate to pack slide relative to the inner surface 933 of the liner, the throttle plate 92, a torque converter 792(Th), and a static pressure torque 793(Tp) with a static pressure of the pipeline 82(Ps) as shown in FIGS. Fig. 7E and 7F shown. Two ends of the outer edge 922 of the throttle plate in a diametrical direction each form a horizontal sealing face 635. The sealing face 635 is formed corresponding to the horizontal sealing plane 632 of the liner 93. Two sides of the sealing face 635 and the annularly curved surface 923 are each attached to the lateral cutting edges 636. The lateral cutting edge 636 is formed as an arc. The lateral cutting edge 636 is formed for sealing corresponding to the joining edge 633 of the sealing plane 632. The sealing face 635 and the sealing plane 632 are pressed axially and perpendicularly against each other for sealing. The seal between the lateral cutting edge 636 and the joining edge 633 is changed from a perpendicular seal to a radial seal.However, since the sealing plane 632 and the tubular portion 931 have different thicknesses, special treatment is required to create a seal to prevent leakage in terms of pressure resistance. When the valve is closed, the outer edge 922 of the throttle plate and the inner surface 933 of the liner are tightly brought to form the band seal 62 or the linear seal 61, with the stem hole surface 634 and a shaft seal surface 637 pressed against each other, and the mating edge 633 and the side cut edge 636 tightly abutting each other. With these continuous packing surfaces, a sealing surface 635 is formed. Two sealing end surfaces 635 each have a projecting structure, which will be referred to as a throttle plate projection 927 hereinafter. A stem hole 928 and a shaft seal surface 637 are formed in the center of the throttle plate projection 927. The valve shaft 95 is received in the shaft hole 928.The shaft sealing surface 637 and the shaft hole surface 634 are pressed together for sealing. The shaft sealing surface 637 and the outer edge 922 of the throttle plate are fastened to form a complete sealing surface 6. Generally, the throttle plate projection 927 is also a part of the throttle plate 92 with the greatest thickness. The . Fig. Figure 7B shows that in some designs two throttle disc projections 927 are attached to each other via a diametrical connection 929, while in the case of the Fig. 7A is not the case. With the diametrical connection 929 and the throttle disc projections 927, the strength of the structure can be increased, but the area of ​​a flow channel 8 is reduced and the flow rate performance is significantly impaired, ie, a reduction of the coefficient Cv (see Fig. 7F).

[0008] The Fig. 7A shows that a portion of the throttle plate 92 along a cross section aa has a rotation radius Ra and is defined as a position close to the valve shaft 95. A portion thereof along a cross section cc has a rotation radius Rc and is defined as a position perpendicular to the valve shaft and having a largest diameter in the horizontal direction. A portion thereof along a cross section bb has a rotation radius Rb and is defined as a position between the above-mentioned positions.

[0009] The Fig. 7E illustrates the creation of the torque converter 792(Th) of the valve shaft. When two gap passages 81—i.e., a gradually reducing flow channel 815 and a sharply expanding flow channel 814—are formed between two sides of the throttle plate flanks 921 and the liner 93, a circulation zone 812 with an asymmetric flow and cavitation generated in a fluid streamline 811 and different pressures are applied to the two sides of the throttle plate flanks 921, by which the torque converter 792(Th) is created. This phenomenon is more obvious in a large throttle valve.

[0010] The Fig. 8Ai, Fig. 8Aii, Fig. 8Aiii and Fig. 8D show a band seal 92b of the throttle plate. Fig. 9Ai, Fig. 9Aii, Fig. 9Aiii and Fig. 9D shows an orifice plate of the linear seal 92a. When the orifice plate 92 is fully opened, it is aligned with a central axis by 0 degrees. When the orifice plate 92 is fully closed, it is aligned with the central axis by 90 degrees. When the orifice plate 92 changes from a fully opened state to a closed state, the part along the cross section aa first comes into contact with the rubber liner 93, after which the parts along the cross section bb and the cross section cc come into contact with the liner sequentially. A location where the above-mentioned members come into contact is referred to as a contact point 72. The contact angle varies depending on the different shapes of the orifice plates.An included angle, hereinafter referred to as contact angle 71(θ), is formed between a joint line defined between the contact point 72 and the axial center of rotation and the central axis at 90 degrees. Under the same packing quantity 65(ε), the part along the cross section aa has the largest contact angle 71(θ), while the part along the cross section bb has the smaller contact angle 71(θ), and the part along the cross section cc has the smallest contact angle 71(θ). This is because the part along the cross section aa has the largest distance between the contact point 72 and an axial center, the part along the cross section bb has the shorter distance between the contact point 72 and the axial center, and the part along the cross section cc has the shortest distance between the contact point 72 and the axial center. The . Fig. 8D and Fig. 9D shows that two sides of the annularly curved surface 923 of the band seal 92b of the throttle plate each have a periphery with a rounded edge and a small radius of curvature, which will be referred to as the throttle plate angle 923a hereinafter. When rotating, the throttle plate angle 923a first comes into contact with the inner surface 933 of the liner, while the conically curved surface 924 of the throttle plate of the linear seal 92a comes into contact with the inner surface 933 of the liner. The contact angles 71(θ) of the band seal 92b of the throttle plate at the parts along the above-mentioned cross sections are all larger than those of the throttle plate of the linear seal 92a. As the contact angle 71(θ) is larger, the distance between the interference sliding θ and the deformation of the inner surface 933 of the liner is larger.

[0011] The Fig. 8B and Fig. 9B shows that the packing quantity 65(ε) is derived from a difference between an outer radius of the throttle plate 92 and an inner radius of the liner 93 when the valve is fully closed. The compression ratio of the liner 93 is a number of the packing quantity 65(ε) compared to a thickness 941(s4) of the backup ring 94. The number of the compression ratio varies depending on the compressive strength requirement and the hardness of the material. A larger compression ratio results in greater compressive strength, but the liner 93 is subject to greater abrasion and its service life is shortened. The compression ratio is between 15 percent (15%) and 25 percent (25%).

[0012] The Fig. 8C and Fig. 9C show that a throttle valve with a caliber of 3 inches is used as an example. The Fig. Fig. 8C shows that the thickness of a metal plate 92c of an outer edge 922 of the band seal 92b of the throttle plate according to the prior art with a caliber of 5 mm and a rounding radius of the rounded corner 923a is 0.5 mm, whose sealing width is 4 mm. Fig. Figure 9C shows that the thickness of a metal plate 92c of an outer edge 922 of the throttle plate of the prior art linear seal 92a with the same caliber is 2 mm, and the sealing width is 2 mm. If the throttle plate 92 is not fully closed in a right-hand position, there is a risk of static pressure leakage.

[0013] When the outer edge 922 of the throttle disc of the band seal 92b of the throttle disc presses against the inner surface 933 of the liner, the larger the used packing quantity 65(ε) and sealing width 63(B), the higher the pressure exerted by the static pressure of the pipeline 82(Ps). When the outer edge 922 of the throttle disc 92 contacts the annularly curved surface 923 as shown in the Fig. As shown in Figure 8C, it is desirable to achieve a pressure sealing effect that offers a large sealing width 63(B), a lower pressing pressure 64(P), a small packing quantity 65(ε), and that has resistance to high temperatures and high pressure when pressed against the inner surface 933 of the liner. For example, if the sealing width 63(B) is equal to or greater than 4 mm (≧ 4 mm). Using a 3-inch throttle valve as an example, the outer edge 922 of the inner metallic throttle plate 92c of the throttle plate 92 does not concentrate its pressure on a fluoroplastic encapsulation 69, preventing a large amount of deformation of the encapsulation 69a and thus reducing the deformation of the liner 68(δ) generated with the inner surface 933 of the liner. When the outer edge 922 of the throttle plate is the conically curved surface 924 (see Fig. 9C), it is desirable to achieve a sealing effect that provides a smaller sealing width 63(B), a higher pressing pressure 64(P), and a larger packing quantity 65(ε) when pressed against the inner surface 933 of the liner. For example, the sealing width 63(B) is equal to or less than 3 mm (≦ 3 mm). Using a 3-inch throttle valve as an example, the narrow outer edge 922 of the inner metallic throttle plate 92c of the throttle plate 92 concentrates its pressure on the fluoroplastic encapsulant 69, generating a large amount of deformation of the encapsulant 69a, while the deformation of the liner 68(δ) generated with the inner surface 933 of the liner is relatively larger. It is obvious that the width of the sealing surface 68 of the linear seal 61 is smaller than that of the band seal 62.

[0014] The Fig. 9C shows that the packing quantity 65(ε) and the sealing width 63(B) of the outer edge 922 of the throttle plate are insufficient, and leakage is likely to occur, especially when the throttle plate 92 is not properly closed, the sealing width 63(B) of the linear seal 61 is seriously short. The prior art design measure is directed to the part in the horizontal diameter along the cross section cc, where the outer diameter of the throttle plate 92 cannot be a complete circle. Instead, it is analogous to an elliptical shape. This results in a partial increase in the packing quantity 65(ε) along the cross section cc to prevent leakage upon improper closing. However, an increase in a friction force 75(F) and a corresponding increase in the torque requirement 79(T) of the valve shaft occurs upon closing.

[0015] The Fig. 8E shows that a contact surface where the outer edge 922 of the throttle plate 92 contacts the deformation of the liner 68(δ) forms a sliding surface by interference sliding δ and defines a sliding angle 74(ψ). The sliding angle 74(ψ) is formed by a tangent of the sliding surface and a tangent of the inner surface of the liner perpendicular to the axial center of the valve. A sliding contact surface is formed by a sliding surface where the small rounded corner of the angle 923a of the band seal 92b of the throttle plate contacts the deformation of the liner 68(δ). The material of the inner surface 933 of the liner on the back side of the outer edge 922 of the throttle plate resists the stress. The inner surface 933 of the liner on the front side resists the frictional force 75(F), whereby the material is pressed to form a protruding deformation of the liner 68(δ).Due to the frictional force 75(F), the outer edge of the metallic throttle plate 92c is stretched, and the fluoroplastic encapsulant 69 is pressed by it, generating deformation of the encapsulant 69a. Generally, the structure of the fluoroplastic encapsulant 69 is reinforced by the connecting holes 513 on the metallic throttle plate 92c by the prior art method to extend its service life (not shown).

[0016] The Fig. 9E illustrates the interference sliding 7 of the linear seal 61 along the cross section aa during closing. The conical curved surface 924 formed with the sliding angle 74(ψ) is larger than that of the forward sliding band seal. In other words, the conical curved surface 924 of the outer edge 922 of the throttle plate applies the frictional force 75(F) to press against the inner surface 933 of the liner, so that the pressed position is depressed and the material is pushed to form a protrusion on the front side. Accordingly, the deformation of the liner 68(δ) is formed. The material on the back side withstands greater stress. The outer edge of the metallic throttle plate 92c applies a greater frictional force 75(F) to the fluoroplastic encapsulant 69 for pressing and extending, thus generating a greater deformation of the encapsulant 69a. Therefore, the service life of the fluoroplastic encapsulation 69 is shorter.

[0017] The Fig. 8E and Fig. 9E shows that the liner 93 is actuated by the throttle plate 92 during closing by interference sliding, with the throttle plate 92 resisting the frictional torque 794(Tf) generated by the frictional force 75(F) until this throttle plate 92 is fully closed. The static pressure torque 793(Tp) of the valve shaft is generated when the throttle valve 9 is closed, but the throttle plate 92 is not fully closed in the correct position. Since the static pressure of the pipeline is applied to both sides of the throttle plate flanks 921, a direction of rotation 791 and a direction along with the pressure are clockwise and counterclockwise, thereby generating the static pressure torque 793(Tp).

[0018] If the packing quantity is 65(ε) when comparing the Fig. 8E with the Fig. 9E larger than those in the Fig. 8B and Fig. 9B, or when the sliding angle 74(ψ) is larger, a large amount of material deformation is easily caused. If the contact angle 71(θ) of the band seal is larger, the sliding distance is larger, requiring more material to absorb the deformation, and the risk of creep is also greater. Under the same packing quantity 65(ε), the larger sliding angle 74(ψ) of the linear seal 61 indicates that a large amount of material deformation is concentrated in a small area, and creep is likely to occur in the material, shortening the service life.

[0019] The problems concerning the above-mentioned state-of-the-art method and the fulfillment of the specific specifications and requirements are described below: Problem 1: Material deformation related to the deformation of the liner 68(δ) and the deformation of the encapsulation 69a. With a larger packing quantity 65(ε), the sealing performance and resistance to the static pressure of the pipeline 82(Ps) are improved. However, creep is prone to occur and high torque is required. These conditions also adversely affect the interference sliding 7 during rotation. In particular, the service life of the throttle valve is shortened at high temperatures. The band seal 62 utilizes a larger sealing width 63(B), a lower pressing pressure 64(p), and a lower packing quantity 65(ε) to achieve a sealing effect resistant to high pressure and high temperatures.The linear seal 61 uses a smaller sealing width 63(B), a higher pressing pressure 64(P), and a larger packing quantity 65(ε) to achieve a sealing effect resistant to high pressure, but creep is easy to occur, thereby impairing the temperature resistance. Problem 2: Interference sliding. Due to interference sliding, a larger contact angle 71(θ), a larger sliding distance, and greater deformation of the liners 68(δ) occur at the portion of the band seal 62 along cross section aa. The portion along cross section aa is easily worn and causes creep, increasing the risk of leakage and shortening the service life of the throttle valve. The portions of the linear seal 61 along all cross sections exhibit the smallest contact angle 71(θ) and the largest sliding angle 74(ψ).At high temperatures or with a large packing quantity 65(ε), a relatively large amount of deformation of the liners 68(δ), deformation of the encapsulant 69a, and frictional forces 75(F) are exerted on both the fluoroplastic encapsulant 69 and the inner surface 933 of the liner. This phenomenon shortens the service life of the fluoroplastic encapsulant 69 and the inner surface 933 of the liner. The most important thing is to solve this problem. Problem 3: Shaft hole surface. The shaft hole surface 634 is coupled to the shaft sealing surface 637 for sealing and is pressed against it. If the shaft hole surface 634 has a larger sealing width 63(B), the seal is more complete, but greater sliding friction is generated. It is important to fulfill the rotational function of the throttle plate 92 and prevent wear and creep caused by sliding friction. This also affects the problem of the seal between the joining edge 633 of the sealing plane 632 and the lateral cutting edge 636 of the horizontal sealing face 635. Problem 4: Flow channel 8, structure of throttle plate 92, structure of the annular surface of the outer edge 922 of the throttle plate, and structure of the inner surface 933 of the liner. Reducing the area of ​​flow channel 8 will degrade the performance of the throttle valve. The throttle plate projection 927 of the diametrical joint 929 occupies a larger area of ​​the flow channel. Problem 5: Torque converter (Th) and static pressure torque (Tp). When forming two gap passages 81 between two sides of the throttle plate flank 921 and the liner 93, the part of the throttle plate 92 with cross section cc resists the largest torque converter 792(Th) due to its longest rotating lever arm 73(R), resists the largest static pressure torque 793(Tp) upon closing, and also resists the largest static pressure torque 793(Tp) upon creating the smallest contact angle 71(θ) because the faulty closed state results in the largest decrease in packing quantity 65(ε). The design of the prior art method is to increase the packing quantity 65(ε) of the part along cross section cc to resist the static pressure torque, thereby also increasing the torque requirement 79(T). Problem 6: High temperature resistance. The liner 93 utilizes the support provided by the valve stem 91 to reduce the shrinkage of the tubular part 931 under high temperatures. High pressure and high temperature resistance are achieved by an appropriate packing quantity 65(ε) and proper interference sliding 7, thus preventing a loss of strength of the fluoroplastic material due to creep. The backup ring 94 requires additional expansion space through the groove 912 to accommodate volume expansion at high temperatures. The band seal 62 has better temperature resistance and pressure resistance. The linear seal 61 cannot provide temperature resistance performance. Problem 7: Strength of the throttle plate 92. With a thicker band seal 92b of the throttle plate instead of the diametrical joint structure 929, not only can the concentration of loads in the center of the throttle plate be improved, but the strength can also be increased and better flow performance can be guaranteed.

[0020] Various prior art embodiments are listed below in response to the problems described above, as well as the specific specifications and requirements for determining their effectiveness: Reference 1:

[0021] A 1968 publication, US Pat. No. 3,376,014, describes a replaceable and substantially rigid valve unit made of fluorocarbon resin for use in throttle valves. The object of this reference is to fabricate a structure in which the liner and support ring are replaceable. A symmetrical throttle valve consists of a two-piece valve stem, a throttle disc encapsulated in fluoroplastic, a liner, and a support ring, the two tubular ends of which are formed with flanges. The throttle disc is formed with a diametrically opposed joint having a relatively greater thickness and stem holes at two ends, and exhibits high strength. The throttle disc flanks are formed in a thick, plate-like structure.If the inner surface of the liner is cylindrical, the outer edge of the orifice plate presses against the inner surface of the liner, creating a band seal capable of sealing up to a pressure limit of 200 psi (i.e., ≦ 200 psi). If the inner surface of the cylinder of the liner protrudes inward to form a trapezoidal cross-section, with a peripheral groove formed in a central position to accommodate the outer edge of the orifice plate, creating a slotted band seal capable of sealing up to a pressure of greater than 400 psi (> 400 psi).

[0022] Reference 1 still has the following problems: Problem 1: Extent of material deformation. The sealing effect of the band seal is ≦200 psi, resulting in a low degree of material deformation and insufficient compressive strength. The inner surface of the liner, with its protruding trapezoidal cross-section and groove, has a sealing capacity for pressures exceeding 400 psi, but a large degree of material deformation occurs, and the torque and service life requirements cannot be met. Problem 2: Interference sliding. When the throttle plate opens and closes, the contact angle between the outer edge and the inner surface of the liner with the protruding trapezoidal cross-section decreases, resulting in interference sliding with a large amount of material deformation at the outer edge and the inner surface of the liner with the protruding trapezoidal cross-section. The packing quantity therefore increases rapidly, requiring a larger torque. Problem 3: Shaft hole surface. The solution is to add a sealing ring to the shaft sealing surface. Problem 4: Flow channel. The inner surface of the liner, with its protruding trapezoidal cross-section, causes a reduction in the area of ​​the flow channel. The throttle plate projection has a relatively large thickness, and the area of ​​the flow channel is reduced accordingly. Problem 5: Torque converter and static pressure torque. No description. Problem 6: Resistance to high temperatures. The volume of the material in the protruding trapezoidal cross-section of the tubular part is too large to prevent shrinkage after exposure to high temperatures. The support ring cannot maintain the strength of the structure at high temperatures, so the resistance to high temperatures is significantly compromised. Problem 7: Strength of the throttle plate. The radial connection and the throttle plate projection are present, as is the thick, plate-like cross-section, ensuring high strength. Reference 2:

[0023] US Pat. No. 3,447,780, published in 1969, describes a plastic resin-lined throttle valve with improved sealing measures. This reference was invented after Reference 1. The described liner is thicker, with the thickness of the material being thinner in the center of the tubular part to form a rectangular groove on the outside and insert a backup ring into it, the cross-section of this rectangular groove having a rectangular shape with rounded corners. When the outer edge of the throttle disc presses against the inner surface of the liner with the reduced thickness, the inner surface of the liner, to which the force is transmitted, can be fully supported by the backup ring with high elasticity, with the material neither stretching nor deforming. The pressed surface becomes a linear seal with a narrow width.Grooves and a long sealing ring are also formed on the shaft sealing surface and the shaft hole surface, with both ends of the sealing ring being formed in a wedge shape so as to achieve a seal with a pressure of up to 500psi, i.e. ≦ 500psi, at 400°F.

[0024] Reference 2 still has the following problems: Problem 1: A throttle plate with a conical cross-section and a significant amount of material deformation. The outer edge of the throttle plate has a conically curved surface to create a linear seal, which can achieve sealing at pressures up to 500 psi (i.e., ≦ 500 psi) at 400°F and meets the low torque requirement. However, the material of the tubular part has different thicknesses, the sealing surface utilizes a thin material structure, and the backup ring is not secured to the valve stem groove. Due to the lack of descriptions, it cannot be determined whether the temperature at 400°F and long-term use of the structure with different thicknesses can meet the pressure resistance and service life requirements. Problem 2: Interference sliding. The linear seal has a small contact angle, so it doesn't cause large amounts of material deformation and eliminates the need for higher torque when interference sliding occurs during opening and closing. Problem 3: Stem hole surface. Annular grooves with a wedge-shaped cross-section are formed on the shaft sealing surfaces at the two ends of the throttle plate and on the corresponding stem hole surfaces of the liner to accommodate the fluoroplastic seal ring. The elliptical structure, whose two ends are wedge-shaped, provides sealing for a pressure of up to 500 psi, i.e., ≦ 500 psi, at 400°F. However, the descriptions neither detail the connection between the linear seal plane and the seal ring and the sealing mechanism, nor address the question of whether the service life can meet the requirement, i.e., whether the throttle plate can be rotated without being worn. Problem 4: Flow channel. The inner surface of the liner with its cylindrical cross-section does not affect performance, while the throttle plate boss with its radial connection does. Problem 5: Torque converter and static pressure torque. No description. Problem 6: High-temperature resistance. The rectangular groove on the outside of the tubular part enlarges when the support ring expands or deforms, so the support ring does not need to be supported and the ring cannot be held. Consequently, the high-temperature resistance is significantly compromised. Reference 3:

[0025] A 1972 publication, US Pat. No. 3,661,171, describes a throttle valve. The subject of this reference is to improve the sealing function when the throttle valve is fully closed. A symmetrical throttle valve consists of a two-piece valve stem, a fluoroplastic-encapsulated throttle disc, a liner, and a backup ring, the two tubular ends of which are formed with flanges. Two ends of the throttle disc are formed with projections, and a valve shaft is provided to form a highly rigid and flat structure. A band seal is constructed with an outer edge of the throttle disc. A groove is formed in an inner diametrical surface of the valve stem to accommodate the backup ring. The width of the groove is slightly larger than the thickness of the outer edge of the throttle disc. Two outwardly projecting and parallel radial ribs are formed on the outside of a cylinder.The backup ring with a round cross-section can be inserted between the two ribs and then inserted into the groove of the inner diametrical surface of the valve stem. With the backup ring, the inner surface of the liner is formed with a radial protrusion of 0.036 inches in the center, thus forming a depressed area and a raised area on the inner surface of the liner. Two sides of the cylinder are each 0.028 inches less than the central protrusion, in other words, the central part of the cylinder cross section is less than 0.008 inches to recess it. When the outer edge of the throttle plate presses against the inner surface of the liner, the backup ring is flattened to make the inner surface of the liner flat. The friction caused by the interference sliding of the outer edge of the throttle plate is correspondingly reduced, so that the torque is not increased and the throttle plate is not worn during rotation.This reference incorporates further modifications by forming the outer edge of the throttle plate into a conically curved surface to form a linear seal so that the lining material can absorb less tensile stress to reduce the occurrence of creep and friction as well as the requirement for torque to extend the service life of the throttle valve.

[0026] Reference 3 still has the following problems: Problem 1: Extent of material deformation. The inner surface of the cylindrical liner forms protrusions with the support ring, and the original band seal achieves a sealing effect similar to that of a linear seal. However, the sealing width and packing quantity are still limited due to the size of the sealing ring. Considering the rubber sealing ring with a diameter of 10 mm, the packing quantity used is approximately 0.91 mm (0.036 in), and the calculated compression ratio, which is less than 10 percent (<10%), appears to be too low. The effectiveness cannot be supported by any reference documents. When the outer edge of the throttle plate is formed into a conically curved surface, the compressed area is reduced, and the compressive strength is also reduced when forming the linear seal. Problem 2: Interference sliding. The inner surface of the liner is constructed with a 0.008-inch micro-recess and a 0.036-inch protrusion at its center, creating a design analogous to a linear seal. The contact angle formed when the orifice plate rotates is smaller, and the torque requirement is lower. These two conditions reduce friction caused by interference sliding between the orifice plate and the liner. Two radial and parallel protruding ribs are formed on the outer surface of the liner cylinder to reduce material deformation of the inner surface of the liner caused by interference sliding and extend service life. Problem 3: Shaft hole surface. A sealing ring structure is attached to the support ring, with an additional cup provided to reinforce the sealing of the shaft hole surface. Problem 4: Flow channel. The inner surface of the liner has a 0.036-inch protrusion, which is supported by a backup ring. The effects caused by the reduction in the flow channel area are not obvious. The throttle plate protrusion formed on the shaft does not extensively occupy the flow channel area, and the throttle plate with its flat cross-section also does not affect performance. Problem 5: Torque converter and static pressure torque. No description. Problem 6: High-temperature resistance. When using the silicone rubber support ring at high temperatures, expansion space may be created. Two parallel and radial ribs formed on the outer edge of the liner's cylinder can maintain high-temperature resistance. Problem 7: Strength of the throttle plate. The published structure consists of the throttle plate boss and its throttle plate, which have a flat cross-section, allowing the load to be concentrated in the central part. This is suitable for small and medium-sized throttle valves. Reference 4:

[0027] A 1998 Japanese document JP H10-78 143 A describes a sealing ring for a throttle valve. This reference was invented with reference to two prior art embodiments, namely a 1979 Japanese document JP S54-103 645 U describing a throttle valve, and a 1980 Japanese document JP S55-142 169 A describing a sealing ring for a throttle valve. The subject of this reference is to improve controllability of the linearity of the flow of the small flow rate when opening the valve by a small degree, as well as to create the throttle disc with the necessary annular lining to meet the condition of the ability of the outer edge of the throttle disc to press against two curved surfaces of the inner surface of the lining when rotating.This reference describes a throttle valve with a rubber liner for general use at room temperature. The rubber exhibits high deformability and elasticity, but lacks corrosion resistance and high-temperature resistance. The throttle disc uses a metal plate, while the outer edge of the throttle disc, with a conically curved surface, can form a linear seal. The approach to solving the problems and the related descriptions can provide the answers to questions 1 to 7, which also explain why the prior art embodiments of this reference cannot meet the need for using the fluoroplastic liner with higher hardness and strength at high temperatures and under high pressure.The inner surface of the liner of this reference is a curved surface that protrudes inward and has an annular structure with a mountain-shaped cross-section, which is referred to as a mountain structure hereinafter. An apex of the mountain structure is annularly distributed over an inner surface of a liner along a central axis of a shaft hole surface of the liner. The mountain structure is divided into two semicircular parts by two shaft holes. Two shaft hole surfaces allow the shaft sealing surfaces of the outer edge of the throttle plate to seal. The cross-section of the mountain structure uses the central axis of the shaft hole surface as a center and forms two-piece symmetrical curves, thus forming two-piece slopes on both sides of the mountain structure. The mountain structure has different widths at different circumferential angles, in other words, the two-piece curves have different lengths.The stem hole end of the mountain structure has a smaller width along a cross-section aa, while a portion of it, formed at a distance from the stem hole end, has a larger width along a cross-section cc. The edges of the two-piece slopes are parallel to each other. This mountain structure is used to increase the strength of the rubber liner structure. When the valve closes, the throttle disc presses against the two-piece slope of the inner surface of the liner. This means that the contact angles between the outer edge of the throttle disc and the inner surface of the liner are significantly reduced and approximately equal to each other. The friction length of the interference sliding is significantly shortened, reducing the torque requirement and extending the service life of the throttle valve.Further embodiments, such as Taiwanese document TW 496934 B published in 2002, describe a throttle valve and a thin seal ring, and Japanese document JP 2003-14139 A published in 2003, describe a throttle valve to improve the above annular structure, whose inner surface of the liner has an asymmetrical trapezoidal cross-section, thereby promoting the sealing effect of the valve and reducing the torque requirement. These prior art embodiments can be considered as further modifications of this reference. However, it is obvious that such a structure made of a rubber material cannot be used for the fluoroplastic material. The problems are described below: Problem 1: Extent of material deformation. The throttle plate can cause a large amount of material deformation in a small area. The rubber liner enables a linear seal with a large amount of material deformation. The structure with the mountain-shaped cross-section has sufficient strength. If fluoroplastic is used to form this mountain structure, the creep with the large amount of material deformation in the small area cannot be accepted. If the outer edge of the throttle plate is enclosed with the fluoroplastic presses, a narrow metallic arc surface will exhibit creep caused by the seal when the fluoroplastic encapsulation reacts due to the compression. This renders the encapsulation of the throttle plate ineffective, allowing corrosive fluid to penetrate. Problem 2: Interference sliding. When the throttle plate forms a linear seal, the contact angle is relatively smaller, while the mountain structure of the inner surface of the liner has a narrower width at the end of the stem hole along the cross-section aa and a steeper curved surface. The packing quantity increases accordingly, generating a large amount of deformation and a large friction force. Regarding the fluoroplastic liner, the interference sliding of the throttle plate must be carried out at the end of the stem hole where the steeper curved surface is formed. The fluoroplastic cannot withstand the large amount of material deformation in a small area and under the high friction force. The risk of leakage near the valve shaft is high, and the service life of the throttle valve is shortened.The fluoroplastic encapsulated throttle plate and the fluoroplastic of the inner surface of the liner are affected by material deformation and creep, resulting in the ineffectiveness of the encapsulation of the throttle plate and the penetration of the corrosive liquid. Problem 3: Stem hole surface. The shaft sealing surface of the outer edge of the throttle plate has extensive interference sealing on the shaft hole surface, and the rubber material is not affected by wear and creep caused by frictional sliding during the rotation of the throttle plate. Fluoroplastic lining must be used to form additional shaft sealing surfaces and stem hole surfaces, because the extensive pressing causes creep and wear due to frictional wear on the pressure surfaces of the fluoroplastic, resulting in leakage and shortening the service life of the throttle valve. Problem 4: Flow channel. The inner surface of the liner has a mountainous structure, which reduces the area of ​​the flow channel and impairs the performance of the throttle valve. The metallic material has a throttle disc protrusion with a radial connection, and this design occupies the area of ​​the flow surface. Problem 5: Torque converter and static pressure torque. No description. Problem 6: High-temperature resistance. Rubber materials generally lack high-temperature resistance. The volume of fluoroplastics with their protruding trapezoidal cross-sections is too large, so the structural strength cannot be maintained at high temperatures, and their temperature resistance is significantly compromised. Problem 7: Strength of the throttle plate. The diametrical connection and the throttle plate projection are present, and the conical cross-section is also present, ensuring high strength. Reference 5:

[0028] A 2003 Japanese publication JP 2003-166654 A describes a throttle valve. The object of this reference is to create a throttle valve with good sealing performance at high temperatures and at room temperature, while maintaining the required torque during expansion of the backup ring at high temperatures. This measure consists in forming volume distribution troughs on the inner peripheral surface of the valve stem to expand the rubber backup ring at high temperatures, thereby reducing the compressive force exerted on the inner surface of the fluoroplastic liner. When the throttle plate forms the linear seal and the outer edge of the throttle plate creates interference sliding and friction with the inner surface of the liner, the amount of volume interference is reduced, and the torque does not increase.

[0029] Problem 1: Extent of material deformation. When forming the linear seal with a fluoroplastic-enclosed throttle plate, the problem of seal creep, which leads to a large amount of material deformation, is not easily overcome. However, high pressure resistance cannot be maintained.

[0030] Problem 2: Interference sliding. When forming the linear seal with the fluoroplastic-enclosed throttle plate, the contact angle becomes smaller. A protruding slope is formed on the rubber support ring, so the area for interference sliding between the throttle plate and the inner surface of the liner is smaller and there is a low friction torque requirement. The narrow metallic arc exerts less stress or shear forces on the enclosed fluoroplastic. This also does not render the enclosed fluoroplastic of the thin throttle plate ineffective.

[0031] Problem 3: Shaft hole surface. No description.

[0032] Problem 4: Flow channel. A protruding slope forms on the rubber support ring. If the inner surface of the liner protrudes slightly inward, the performance of the throttle valve is not affected. The area of ​​the flow channel occupied by the throttle disc projection and the radial connection is large, and this arrangement impairs performance.

[0033] Problem 5: Torque converter and static pressure torque. No description.

[0034] Problem 6: Resistance to high temperatures. Volume distribution troughs are formed on the inner peripheral surface of the valve stem. This arrangement allows the rubber support ring to expand at high temperatures, thus reducing the compressive force exerted on the inner surface of the fluoroplastic liner. However, at high temperatures, the sealing performance of the linear seal is compromised.

[0035] Problem 7: Strength of the throttle plate. The diametrical connection and the throttle plate projection are present, and the conical cross-section is also present, ensuring high strength. Reference 6:

[0036] A Japanese publication JP 2012-219819 A, published in 2012, describes an airtight throttle valve structure. The subject of this reference is to improve the sealing performance of the throttle valve and, more specifically, relates to a structure in which an annular spherical recessed surface is formed at the center of the inner surface of the liner and a stem hole surface connected to this spherical recessed surface. The described structure allows the outer edge of the throttle disc to form an effective surrounding band seal, thereby increasing the sealing effect of the valve and reducing the need for torque. After comparison and analysis, compression deformation can be generated evenly to achieve an effective sealing effect.

[0037] Problem 1: Extent of material deformation. When forming the band seal through the throttle plate, the annular, recessed, and spherical structure with a small surface area is used to create a sealing effect at the location where a larger pressure area is caused by the outer edge of the throttle plate, but only a small amount of volumetric deformation occurs. The creep problem through the seal, which leads to a large amount of material deformation, does not easily occur. The compressive strength is achieved.

[0038] Problem 2: Interference sliding. The thickness of the fluoroplastic-coated orifice plate is increased, so the annular, recessed, and spherical surface is used to reduce the contact angle when forming the band seal. Furthermore, the material generates only a small packing volume during interference sliding with friction, requiring only low torque. Only a small amount of the volume is subjected to interference friction, while the stress and shear forces to which the thin-coated fluoroplastic of the recessed spherical surface is subjected are reduced. The service life of the thin-coated fluoroplastic of the recessed spherical surface is longer.When the outer edge of the fluoroplastic enclosed orifice plate causes interference sliding by friction, with the inner metallic angle of the orifice plate, less stress or shear force is exerted on the enclosed fluoroplastic, and no creep is applied to the enclosed fluoroplastic.

[0039] Problem 3: Shaft hole surface. The original spherical surface is retained, but the contact surface of the extensive surface continues to show wear.

[0040] Problem 4: Flow channel. A small, annular, recessed, and spherical surface is formed in the center of the inner surface of the liner, so that the flow channel area is not reduced and the performance of the throttle valve is not affected. The area of ​​the flow channel occupied by the throttle plate projection at two shaft ends is not large. The performance is not affected by the throttle plate with a thick cross-section.

[0041] Problem 5: Torque converter and static pressure torque. No description.

[0042] Problem 6: High temperature resistance. A small annular, depressed, and spherical surface is formed in the center of the inner surface of the liner, so the depressed part of the inner surface of the liner has a smaller thickness. This smaller thickness easily leads to material deformation and easily causes the inner surface of the liner to shrink inward at high temperatures. The inward shrinkage of the depressed and spherical surface at high temperatures affects the temperature resistance. However, the expansion of the rubber of the support ring due to high temperatures also causes the depressed and spherical surface to protrude outward, which affects the temperature resistance.

[0043] Problem 7: Strength of the throttle plate. The throttle plate protrusion and the plate-like cross-section are present. With the thickness that determines the strength of the throttle plate, a small and medium-sized throttle plate with a high-strength structure is formed. Reference 7:

[0044] A 2015 Chinese publication CN 2 04 344 951 U describes a corrosion-resistant, high-precision throttle valve. The purpose of this reference is to create a depressed and spherical structure on the inner surface of the liner, hereinafter referred to as the depressed and spherical surface, in order to improve the sealing performance of the valve and reduce the torque requirement. Fluoroplastic is used as the material of the valve liner, and fluoroplastic is also used as the material of the throttle plate. The reference does not specify whether the metallic throttle plate is encased in fluoroplastic. From the attached drawings, it can be seen that the throttle plate can form a linear seal, while the rubber backup ring is inserted into the inner recess of the valve stem to improve the sealing performance of the depressed and spherical surface.

[0045] Problem 1: Extent of material deformation. When fluoroplastic is used to create such a recessed and spherical surface, the sealing effect is effective in a small area of ​​deformation, while the fluoroplastic-enclosed throttle plate forming the linear seal prevents creep over large areas of material deformation. However, the structure cannot guarantee resistance to high pressure.

[0046] Problem 2: Interference sliding. When the orifice plate forms a linear seal, the contact angle is small, and a smaller area is available for interference sliding during the rotation of the orifice plate. Friction is low, and the torque requirement is low. Tension and shear forces are exerted on the thin-coated fluoroplastic of the recessed and spherical surface without being secured by the rubber of the backup ring. The thin-coated fluoroplastic of the recessed and spherical surface is easily wrinkled, worn, and leads to corrosive fluid penetration.

[0047] Problem 3: Shaft hole surface. The original spherical surface is retained. No further description.

[0048] Problem 4: Flow channel. The inner surface of the liner is a recessed and spherical surface, reducing the effective area of ​​the flow channel and affecting the performance of the throttle valve.

[0049] Problem 5: Torque converter and static pressure torque. No description.

[0050] Problem 6: High temperature resistance. The inner surface of the liner is a depressed and spherical surface, meaning that the cross-section of the inner surface of the liner expands to form a straight length in the direction of the flow channel. This length is greater than the width of the valve stem. The depressed and spherical surface shrinks inward at high temperatures, while the structure of the depressed and spherical surface is not supported by the support ring. Furthermore, the rubber of the support ring expands toward the spherical center at high temperatures, significantly affecting the temperature resistance.

[0051] Problem 7: Strength of the throttle disc. A protruding disc boss and a conical cross-section are provided to ensure resistance to high temperatures and high pressure. Reference 8:

[0052] A 2016 Japanese document JP 2016-41 967 A describes a valve stem of the throttle valve and the throttle valve. This reference was invented with reference to two prior art embodiments: a 2004 Japanese document JP 2004-239 343 A, which describes a valve element of the throttle valve, and a 2007 Japanese document JP 2007-32 683 A, which describes a throttle valve. This reference relates to a metallic throttle disc, and the means of this reference are also used for a fluoroplastic-enclosed throttle valve. The subject of this reference is to improve the weight and flow resistance of the throttle valve and to reduce torque.This design reduces the weight of the throttle plate structure without compromising its strength, while maintaining high sealing performance and fluid flow. When the throttle plate is closed, the throttle plate has sufficient strength to withstand the pressure from the pipeline, preventing deformation and sealing ineffectiveness. When the throttle plate is open, the flow channel area through the throttle plate in the pipeline flow channel is not reduced, and the throttle plate does not cause an increase in flow resistance due to fluid turbulent flow and cavitation.The throttle plate structure of this reference features a diametrical connection and a throttle plate protrusion in a vertical direction to provide strength to the structure. Furthermore, a rib plate with an elliptical cross-section is provided in a horizontal direction. Near the outer edge of the throttle plate, an annular structure is formed, the thickness of which corresponds to the thickness of the throttle plate, to enhance the structural strength of the throttle plate flanks.

[0053] Problem 1: Extent of material deformation. When forming the linear seal using the throttle plate, the thickness of the diametrical outer surface of the throttle plate's metal plate is 2.5 mm. This reference does not describe the conditions of the inner surface of the liner. When using the fluoroplastic liner, the width of the pressure surface is only 2.5 mm, and this condition does not guarantee resistance to high temperatures and high pressures.

[0054] Problem 2: Interference sliding. This reference does not describe the conditions of the inner surface of the liner. In principle, the linear seal can achieve low deformation and low torque. When used with a throttle plate with a fluoroplastic encapsulation, interference sliding leads to material deformation of the fluoroplastic encapsulation and creep under a large packing density. Therefore, temperature resistance and pressure resistance cannot be achieved.

[0055] Problem 3: Shaft hole surface. The shaft seal surface is a spherical, curved surface.

[0056] Problem 4: Flow channel. The area of ​​the flow channel occupied by the diametrical connection and the throttle plate projection is large. Although the rib plate with the elliptical cross-section occupies the area of ​​the flow channel in the horizontal direction, the turbulent flow in the flow channel continues to decrease.

[0057] Problem 5: Torque converter and static pressure torque. By reducing turbulent flow and cavitation, the torque converter can be reduced.

[0058] Problem 6: Resistance to high temperatures. A linear seal is present, but the temperature resistance cannot be increased.

[0059] Problem 7: Strength of the throttle plate. The diametrical connection and the throttle plate projection are present, with the thickness of the plate-like cross-section being only 2.5 mm. The throttle plate flank is also formed with a ribbed plate with an elliptical cross-section in a horizontal direction, while an annular structure is formed near the outer edge of the throttle plate, the thickness of which corresponds to the thickness of the throttle plate to ensure sufficient strength. Reference 9:

[0060] A 2017 publication CN 1 06 415 087 A from China describes a sealing structure for a throttle valve. The object of this reference is to provide a throttle valve with good sealing performance at high temperatures and at room temperature, wherein the required torque is not increased when the backup ring is expanded at high temperatures. A sealing structure of the throttle valve consists of a liner made of resin and is attached to an inner peripheral surface of the valve stem. The liner has stem holes including stem holes and stem hole surfaces formed in opposite positions in a diametrical direction. The throttle disc has a throttle disc projection that can traverse the liner and the rubber backup ring and is inserted into a stem hole portion of the valve stem. A valve shaft is inserted into a central hole of the throttle disc projection.When the valve shaft rotates, the outer edge of the throttle disc presses against the inner surface of the liner. It is characterized by the formation of an inner diameter of the liner of the valve stem as follows: When the valve is open, the inner diameter of the inner surface of the liner is deformed by the elastic force of the rubber backup ring, becoming smaller than the outer diameter of the throttle disc. When the valve is closed, on the other hand, the throttle disc is pushed and pressed, while the inner diameter returns to its original undeformed state due to the elastic force of the rubber backup ring. The undeformed inner diameter includes the tolerance and is equal to or slightly larger than the outer diameter of the throttle disc.

[0061] Problem 1: Extent of material deformation. The thickness of the outer diametrical surface of the metal plate of the throttle plate is 3 mm. The throttle plate, enclosed in fluoroplastic, forms the linear seal, while the compressed inner diameter of the inner surface of the liner approaches the original diameter, which is not compressed by the rubber backup ring, and also approaches the outer diameter of the throttle plate. In other words, the inner surface of the liner is not compressed by the outer edge of the throttle plate and therefore is not stretched. In this reference, the described compression ratio is approximately 13 percent (13)%, or 1.3 mm / 10 mm.The goal is to reduce creep, which leads to significant material deformation during sealing. A linear seal and a low packing density of approximately 13 percent (13%) are aimed for, resulting in a torque reduction of approximately 23 percent (23%). However, the width of the pressure surface is only 3 mm, so compressive strength and temperature resistance cannot be guaranteed.

[0062] Problem 2: Interference sliding. The linear seal is only achieved between the outer edge of the restrictor disc and the annular sealing surface protruding from the center of the inner surface of the liner, so the contact angle is smaller and the torque requirement is lower. The outer edge of the restrictor disc exerts friction on the inner surface of the liner over a smaller area due to interference sliding. The packing quantity is approximately 13 percent (13%). With the lower stress or shear forces exerted on the inner surface of the liner, the torque can be reduced by 23 percent (23%).An external arc surface of the inner metal sheet of the throttle plate, which has a thickness of 3 mm, exerts the lower stress or shear forces on the enclosed fluoroplastic, and in the same way as the prior art, when through holes are formed through a part of the metal sheet of the throttle plate near the diametrical outer side, the strength of the enclosed fluoroplastic is enhanced, and the design does not lead to the ineffectiveness of the encapsulation of the throttle plate.

[0063] Problem 3: Stem hole surface. Respective protrusion seats are formed on the back surfaces at two ends of the stem hole to improve the sealing performance of the stem hole surface, and these protrusion seats are attached to the inner surface of the liner.

[0064] Problem 4: Flow channel. With the annular sealing surface protruding in the center of the inner surface of the liner, the area of ​​the flow channel is reduced by approximately 5 percent (5%). The throttle plate projection is only formed at two shaft ends, resulting in a small area of ​​the flow channel occupied by the projection. The throttle plate has a conical cross-section, so performance is not affected.

[0065] Problem 5: Torque converter and static pressure torque. No descriptions.

[0066] Problem 6: High temperature resistance. The rubber back-up ring supports the sealing surface, which protrudes in the center of the inner surface of the liner to allow expansion of the rubber back-up ring and form the space between the liner and the valve stem at high temperatures. The excessive pressure exerted on the tubular part of the fluoroplastic liner can be reduced, but the temperature resistance still cannot be increased due to the linear seal.

[0067] Problem 7: Strength of the throttle plate. The throttle plate protrusion and the conical cross-section create a structure with high strength. Reference 10:

[0068] A 2008 Chinese publication CN 1 00 376 828 C describes a miter valve stem. The purpose of this reference is to prevent a reduction in the flow coefficient Cv when the valve is fully open, to reduce fluid resistance at both the full opening and intermediate opening angles, and to achieve a lighter valve stem. Table 1 of this reference shows the flow coefficient Cv. Reference 11:

[0069] A product catalog numbered "Tomoe Valves USA Catalog-846t-847t-847q-20150601" was published by Tomoe Valves Co., Ltd. This reference is one of this company's product catalogs. This product catalog contains a table showing the flow coefficient Cv of the fluoroplastic butterfly valve. The flow coefficient Cv is based on the butterfly valve with a 3-inch caliber.

[0070] From the above discussions regarding the structures of the references and their problems described from 1 to 7, it is clear that at temperatures up to 200°C, i.e., ≦ 200°C, the sealing width and material deformation due to interference sliding are lacking complete solutions, and these do not meet the requirements for temperature resistance and pressure resistance. Furthermore, further clarification is needed regarding the structural performance in terms of low torque, high flow rate, high Cv value, long service life, high reliability, etc. Therefore, the prior art throttle valve approaches with fluoroplastic lining cannot meet the specifications of the special-purpose throttle valve as shown below: Corrosive liquid: Transport fluids such as hydrofluoric acid, hydrochloric acid, and sulfuric acid. Thickness includes corrosion tolerance. Performance and quality: high flow rate, low torque, long service life, resistance to high temperatures, high pressure and high reliability. Highest temperature: for a special purpose ≦ 200°C. Maximum pressure: for a special purpose ≦ 3kg@200°C.

[0071] In addition, a flap valve is known from DE 25 33 155 A1, and a sealing structure for a butterfly valve is known from WO 2015 / 147 197 A1. Object of the invention

[0072] To achieve the above-mentioned objectives, the present invention provides a throttle plate and valve stem that utilize complex sealing means to improve the sealing width of the throttle plate and valve stem at high temperatures, overcome the disadvantages of interference sliding, and maintain high performance. This novel invention provides a throttle valve structure that improves sealing and pressure resistance, reduces torque, improves temperature resistance, and improves valve performance.

[0073] The structure of a fluoroplastic throttle valve consists of a valve stem, a throttle disc, a liner and a support ring.

[0074] The valve stem is formed in the shape of a round ring and divided horizontally into a semicircular two-piece part, i.e., an upper valve stem and a lower valve stem. The two valve stems are fastened together with two fasteners to unite them. The upper valve stem and the lower valve stem are installed in an axial direction. The upper valve stem has a fastening part and a stem hole part arranged thereon, while the lower valve has a fastening part and a stem hole part arranged thereon. An inner peripheral surface of the valve stem is formed to allow installation of the fluoroplastic liner. The inner peripheral surface of the valve stem is recessed inward to form a groove with a trapezoidal cross-section, with which an included angle (γ) is formed.The support ring with a trapezoidal cross-section is accommodated in the groove, forming an included angle (α). A protruding ring is arranged on a bottom surface of the groove. The protrusion (s2) of the protruding ring is less than the groove depth (s1). The protruding width (t2) of the protruding ring is 1.5 to 2 times the thickness (t1) of an inner metallic throttle plate of the throttle plate, but less than the bottom width (t3) of the groove.

[0075] The liner, which is arranged corresponding to the valve stem, is also formed in the shape of a circular ring. The liner has a diametrical inner side and a diametrical outer side. Two ends of the liner each have a radial flange. The liner consists of a tubular part, with two axial ends of the liner each formed with a horizontal sealing plane. The tubular part and the horizontal sealing plane are fastened to each other to form a circular ring. The horizontal sealing planes are all formed as flat surfaces on the diametrical inner side and on the diametrical outer side. A vertical distance between two horizontal sealing planes is smaller than an inner diameter of the tubular part. A thickness of the horizontal sealing plane is greater than a thickness of the tubular part. The thickness covers a diametrical inner side and the diametrical outer side of the liner.A diametrically inner side of the horizontal sealing plane and a diametrically inner side of the tubular part are fastened at a location where an arcuate joining edge is formed. A stem hole is formed on the horizontal sealing plane, with the diametrically inner side and a diametrically outer side of the horizontal sealing plane each forming a stem hole surface. The stem hole surface is formed on an outer periphery of the stem hole for sealing. A sealing recess is formed on the stem hole surface and on the diametrically inner side. The stem hole surface, the joining edge, and an inner surface of the liner formed on the diametrically inner side of the tubular part are fastened to form a complete sealing surface.When the throttle valve is closed, an outer edge of the throttle plate presses against the inner surface of the tubular liner. This tubular part is supported by the valve stem and the support ring to close the flow and withstand the pressure and temperature of the fluid. Reinforcing members are formed on the diametrically outer side of the horizontal sealing plane, arranged along the tubular part on two sides of the stem hole. The width of the reinforcing member is twice the thickness of the inner metallic throttle plate of the throttle plate, thus allowing a smooth variation in the thicknesses of the horizontal sealing plane and the tubular part, thus preventing leakage from the joint edge.

[0076] The support ring is an elastic body made of rubber and inserted between the groove of the inner peripheral surface of the valve stem and the tubular part of the liner. An inner diameter of the support ring basically corresponds to an inner diameter of the valve stem. An outer diameter of the tubular part basically corresponds to the inner diameter of the valve stem. The inner diameter of the support ring and the inner surface of the liner are reduced due to shrinkage during the manufacturing process and protrude inward. These arrangements require process control, whereby a protrusion swelling height is set within a reasonable range. These protrusions must be controlled and taken into account during manufacturing when calculating a packing quantity (ε).

[0077] The throttle plate is formed in the shape of a disc. Two axial ends of the outer edge of the throttle plate each form a horizontal sealing face. The horizontal sealing face is formed according to the horizontal sealing plane of the liner. The horizontal sealing face and an annularly curved surface of the outer edge of the throttle plate are attached at a location where an arcuate lateral cutting edge is formed. The lateral cutting edge is formed according to the joining edge of the horizontal sealing plane for sealing. The horizontal sealing face and the horizontal sealing plane are pressed against each other axially and vertically for sealing. The sealing between the lateral cutting edge and the joining edge is changed from a vertical seal to a radial seal.Because the thickness is smoothed with the reinforcement part, the tight pressing is uniform, and no leakage occurs in terms of pressure resistance. The respective protruding parts and valve shafts are arranged on two horizontal sealing faces. The valve shaft and the protruding part are concentric. The valve shaft has a long valve shaft and a valve shaft. The valve shaft protrudes through two stem holes of the liner and is installed in the stem hole part of the valve stem to allow the throttle plate to rotate to regulate the flow rate or open or close the valve. An outer diameter of the throttle plate is slightly larger than an inner diameter of the inner surface of the liner. With the protruding parts at the two ends, the throttle plate is divided into two throttle plate flanks, and the cross section can be a plate-like cross section or a cone-like cross section.For example, the throttle plate is 3 inches, where a thickness of an outer edge of the throttle plate flank can provide a band seal with a sealing width greater than or equal to 4 mm, ie ≧4 mm.

[0078] When the orifice plate is closed, the outer edge of the orifice plate is pressed against the inner surface of the liner to form a partial sealing surface. The compression ratio of this partial sealing surface corresponds to a number of the packing quantity compared to the thickness of the backup ring. Depending on the material used for the backup ring and the requirements for pressure and temperature resistance, a compression ratio of 15 percent (15%) to 20 percent (20%) is sufficient. The tubular part of the liner expands when forces are applied to it and pressure is exerted on the backup ring, with an outer diameter of the compressed part of the tubular part being larger than the inner diameter of the valve stem.When the throttle disc is opened, the tubular part is drawn inwards by the elasticity of the support ring so that the outer diameter of the tubular part approximately corresponds to the inner diameter of the valve stem.

[0079] A shaft seal surface and a protruding seal ring are arranged on the protruding part. The seal ring and the sealing recess of the stem hole surface of the liner can be press-fitted to reduce the outer diameter of a throttle plate projection. When the annularly curved surface of the outer edge of the throttle plate is pressed against the inner surface of the liner of the tubular part, the annularly curved surface and the shaft seal surface can be pressed against the stem hole surface, while the side cut edge can be pressed against the joining edge to form a continuously reliable sealing surface and reduce wear and creep due to friction caused by interference sliding due to the rotation of the throttle plate.The sealing surface is therefore a closed surface that includes the inner surface of the liner, the joining edge and the shaft hole surface and is also a closed surface that includes the annularly bent surface, the lateral cutting edge and the shaft sealing surface.

[0080] The present invention provides a valve structure with a fluoroplastic throttle plate that has resistance to high temperatures and high pressure and meets the requirements of low torque and long service life. The annularly curved surface of the outer edge of the throttle plate consists of an uneven-width tapered surface and an uneven-width curved surface. A part of the uneven-width tapered surface near the valve shaft has a smaller sealing width, while a part thereof near a central part of the throttle plate has a largest sealing width. The sealing width of the part of the uneven-width tapered surface near the valve shaft is fifty percent (50%) larger than the thickness of the outer edge of the inner metallic throttle plate of the throttle plate.For example, a 3-inch throttle plate is used, and the sealing width of this throttle plate is greater than 4 mm. The portion of the uneven-width curved surface near the center of the throttle plate has a largest sealing width that is 70 percent (70%) larger than the outer edge thickness of the metallic throttle plate. Therefore, the present invention's requirement for static pressure torque resistance and high-pressure airtightness is greater than that of the prior art method with a reasonable package quantity. The uneven-width curved surface extends from one surface of the throttle plate flank to the outer edge.A part of the unequal-width curved surface near the valve shaft has a longest smooth arc, while a part of it near the central part of the throttle plate has a shortest smooth arc to replace the angle of the throttle plate of the prior art band seal. The unequal-width curved surface is arranged in a closing direction of the throttle plate. The unequal-width curved surface is slid relative to the inner surface of the liner by a smaller contact angle 71(θ) and a sliding angle 74(ψ) to reduce material deformation and frictional forces, reduce the contact angle, and significantly shorten the sliding length. The outer edge of the inner metallic throttle plate of the throttle plate also has a corresponding curved surface structure, i.e., an unequal-width conical surface and an unequal-width curved surface.When the valve is closed, the uneven-width tapered surface of the outer edge of the throttle disc and the inner surface of the liner are pressed together to form a complex seal, including the interference fit between the stem hole surface and the shaft seal surface, the seal between the pre-cutting seal ring and the sealing recess, and the tight fit between the mating edge and the side cut edge. The complex seal is created by these continuous tight pressing surfaces.

[0081] The advantages of the present invention are described below: Problem 1: Extent of material deformation. For the conical surface with uneven width of the complex seal, a larger sealing width and appropriate interference fit pressure can be sought to achieve the sealing effect, and a more appropriate compression ratio can be used to meet the sealing requirement. The material of the inner surface of the liner exhibits less deformation, and creep is not easy to occur. Using a larger sealing width means high compressive strength, while larger pressure variations can be guaranteed. The large area of ​​the material can be supported at high temperatures, and the temperature resistance can be increased. With these advantages, the service life of the throttle valve can be extended. Problem 2: Interference sliding. The curved surface of the complex seal with uneven width replaces the angle of the conventional technology. The contact angle formed with the curved surface of uneven width is reduced and the sliding length is shortened, thus achieving a relatively smooth interference sliding operation. The tensile stress and shear forces exerted on the material of the inner surface of the liner are reduced, so that creep of the materials is not likely to occur and the friction force is also reduced. The torque requirement can be reduced, the pressure resistance of the throttle valve and its high temperature resistance can be increased, and the service life of the throttle valve can be extended. Problem 3: Stem hole surface. The protruding seal ring is arranged on the shaft sealing surface of the horizontal seal face and can press against the sealing recess of the stem hole surface of the horizontal seal plane with an interference fit, thus reducing the sealing area. The outer diameter of the throttle disc protrusion can be reduced to increase the flow channel area, which can also reduce wear and creep caused by sliding friction, thus reducing the risk of leakage and extending the service life of the throttle valve. Reinforcing parts are formed on each side of the stem hole to smooth the variation in the thickness of the horizontal seal plane and the tubular part, thus enhancing the sealing ability of the horizontal seal plane. Problem 4: Flow channel. When the throttle disc is opened to form a gap passage, the width of the gap passage is increased with the curved surface of uneven width. The outer edge of the throttle disc becomes a smooth curved surface to facilitate the throttle disc to increase the flow rate by a small open angle. The throttle disc has no diametrical connection, so the area of ​​the flow channel is not extensively occupied. The throttle disc flank has a plate-like cross-section or a conical cross-section, with separate protruding parts with a smaller outer diameter on two sides of the throttle disc valve shaft filling a smaller area of ​​the flow channel. An inner diametrical surface of the liner is cylindrical and the same as the inner diameter of the pipeline to ensure that the area of ​​the flow channel and the flow rate are sufficient. Problem 5: Torque converter and static pressure torque. A gap passage is formed between the throttle plate flank and the inner surface of the liner. With the uneven-width curved surface, the width of the gap passage is increased to allow for greater flow and reduce shedding and turbulent flow, which reduce the torque converter. The smallest sealing width of the uneven-width portion of the tapered surface closest to the valve shaft exceeds the thickness of the outer edge of the inner metal throttle plate of the throttle plate by 50 percent (50%). The smallest sealing width of the uneven-width portion of the tapered surface closest to the center of the throttle plate exceeds the thickness of the outer edge of the inner metal throttle plate of the throttle plate by 70 percent (70%).These arrangements can significantly increase the resistance to static pressure torque and reduce the risk of static pressure leakage. Problem 6: Resistance to high temperatures. The tapered surface with uneven width has a larger sealing width, and the interference sliding of the curved surface with uneven width is smooth, thus reducing the material deformation of the inner surface of the liner and providing better temperature resistance and pressure resistance. The tubular part of the liner has no complicated structure, significantly reducing the deformation caused by high temperatures. The trapezoidal groove formed on the inside of the valve stem can accommodate the expansion of the backup ring caused by high temperatures. Problem 7: Strength of the throttle plate. The protruding parts of the throttle plate are separate and not connected to each other by a diametrical joint. The throttle plate flank has a plate-like cross-section or a conical cross-section, which guarantees high strength. Short description of the drawings Fig. 1 is a schematic view showing the appearance and installation of a fluoroplastic throttle valve of the present invention; Fig. 2A is a cross-sectional view showing a liner with reinforcing members; Fig. Figure 2B shows a plan view illustrating the sealing of the lining with reinforcement members; Fig. 3 is a schematic view showing the combination of the liner with a support ring; Fig. 4A is a plan view showing a throttle plate of the present invention in an axial direction from above; Fig. 4B shows a side elevation view of the throttle plate of the present invention; Fig. 4C is a perspective view showing a tapered surface of unequal width and a curved surface of unequal width of the throttle plate of the present invention; Fig. 4D is a perspective view showing a metallic throttle plate of the throttle plate of the present invention; Fig. 5Ai is a schematic view showing the contact point where the throttle plate and the inner surface of the liner of the present invention meet along section cc; Fig. 5Aii is a schematic view showing the contact point where the throttle plate and the inner surface of the liner of the present invention meet along section bb; Fig. 5Aiii is a schematic view showing the contact point where the throttle plate and the inner surface of the liner of the present invention meet along section aa; Fig. 5B is a schematic view showing the sealing status in which the throttle plate of the present invention is in contact with the liner and exerts compressive forces to deform the liner and the backup ring; Fig. 5C is a plan view showing the throttle plate of the present invention in an axial direction from above; Fig. 5D is a cross-sectional view showing the contact point where the throttle plate of the present invention contacts the inner surface of the liner along section 1-1; Fig. 5E is a cross-sectional view illustrating interference sliding of the throttle plate of the present invention; Fig. 6A is a schematic view showing a gap passage of the throttle valve of the present invention; Fig. Fig. 6Bi is a graph showing the flow coefficient Cv of the throttle valve of the present invention at a different opening angle; Fig. 6Bii shows a curve diagram of the flow coefficient Cv of the 3-inch throttle valve of reference 10 at a different opening angle; Fig. 6Biii shows a curve diagram of the flow coefficient Cv of the 3-inch throttle valve of reference 11 at a different opening angle; Fig. 7A is a schematic view showing an appearance of a prior art fluororesin throttle valve; Fig. 7B is a perspective view showing the structure of a prior art fluororesin-encapsulated throttle plate; Fig. 7C is a schematic view showing the combination of a liner with a backup ring of the prior art fluororesin throttle valve; Fig. 7D is a cross-sectional view showing a tubular part of the liner of the fluororesin throttle valve according to the prior art; Fig. 7E is a schematic view showing the torque required to close the throttle valve with the throttle plate according to the prior art; Fig. 7F is a schematic view showing the torque required to open the throttle valve with the throttle plate according to the prior art to form a gap passage; Fig. 8Ai is a schematic view showing the contact point where a band seal of the throttle plate of the fluoroplastic throttle valve according to the prior art and the inner surface meet along the cross section cc; Fig. 8Aii is a schematic view showing the contact point where a band seal of the throttle plate of the fluoroplastic throttle valve according to the prior art and the inner surface meet along the cross section bb; Fig. 8Aiii is a schematic view showing the contact point where a band seal of the throttle plate of the fluororesin throttle valve according to the prior art and the inner surface meet along the cross section aa; Fig. 8B is a schematic view showing the deformation of the sealing surface and the pressing pressure of the band seal of the fluororesin throttle valve according to the prior art; Fig. 8C is a schematic view showing the shape of the sealing surface of the band seal of the fluororesin throttle valve according to the prior art; Fig. 8D is a cross-sectional view showing the contact point where the band seal of the prior art fluoroplastic throttle plate and the inner surface meet along the cross section aa; Fig. 8E is a cross-sectional view showing the interference sliding of the band seal of the fluoroplastic throttle valve according to the prior art; Fig. 9Ai is a schematic view showing the contact point where a throttle plate of the prior art linear seal and the inner surface meet along the cross section cc; Fig. 9Aii is a schematic view showing the contact point where a throttle plate of the prior art linear seal and the inner surface meet along the cross section bb; Fig. 9Aiii is a schematic view showing the contact point where a throttle plate of the prior art linear seal and the inner surface meet along the cross section aa; Fig. 9B is a schematic view showing the deformation of the sealing surface and the pressing pressure of the linear seal of the fluororesin throttle valve according to the prior art; Fig. 9C is a schematic view showing the shape of the sealing surface of the linear seal of the fluororesin throttle valve according to the prior art; Fig. 9D is a cross-sectional view showing the contact point where the linear seal of the prior art fluoroplastic throttle valve and the inner surface meet along the cross section 1-1; and Fig. 9E is a cross-sectional view showing the interference sliding of the linear seal of the fluororesin throttle valve according to the prior art. Ways to implement the invention

[0082] The Fig. 1, Fig. 2A, Fig. 2B, Fig. 3, Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D show that a symmetrical fluoroplastic throttle valve 1 consists of a valve stem 2, a liner 3, a support ring 4 and a throttle disc 5.

[0083] The valve stem 2 is formed in the shape of a circular ring and divided horizontally into a semicircular two-piece part, i.e., an upper valve stem 21 and a lower valve stem 22. Two fasteners fasten the two valve stems together to unite them. The upper valve stem 21 and the lower valve stem 22 are installed in an axial direction. The upper valve stem 21 has a fastening part 211 and a stem hole part 212 formed therein, while the lower valve stem 22 has a fastening part 221 and a stem hole part 222 formed thereon. An inner peripheral surface 23 of the valve stem 2 is formed for installing the fluoroplastic liner 3.With the inner peripheral surface 23, a groove 232 with a trapezoidal cross section is formed, which forms an included angle 233(γ) in order to insert the support ring 4 with the trapezoidal cross section 42 therein and as shown in the . Fig. 3 to form an included angle 43(α). A protruding ring 234 is provided at the bottom of the groove 232. A height 239(s2) of the protruding ring 234 is less than a groove depth 237(s1) of the groove 232. A width 236(t2) of the protruding ring 234 is as shown in the Fig. 4A shown 1.5 to 2 times greater than a thickness 631(t1) of an inner metallic throttle plate 51 of the throttle plate 5, but less than a lower width 238(t3).

[0084] The liner 3, which is arranged corresponding to the valve stem 2, is formed in the shape of a circular ring. The liner 3 has a diametrical inner side and a diametrical outer side. Two ends of the liner 3 each form a radial flange 32. The liner consists of a tubular part 31. An outer diameter 315 of the tubular part 31 is installed on the inner peripheral surface 23 of the valve stem 2. During closing, an outer edge 53 of the throttle plate 5 of the throttle plate 5 is pressed against the cylindrical inner surface 311 of the liner of the tubular part 31 and supported by the valve stem 2 and the support ring 4 to close the flow of the fluid and bear the pressure and temperature of the fluid. Two axial ends of the liner 3 are each formed with a horizontal sealing plane 632. A thickness of the horizontal sealing plane 632 is greater than a thickness of the tubular part 31.The horizontal sealing planes 632 are provided with a flat structure on the diametrical inner side and on the diametrical outer side so that a diametrical distance between the two horizontal sealing planes 632 is less than an inner diameter of the tubular part 31. A diametrical inner side of the horizontal sealing plane 632 of the liner 3 and a diametrical inner side of the tubular part 31 of the liner 3 are connected to each other, this connection forming a joining edge 633 in an arc shape. A shaft hole 312 is formed on the horizontal sealing plane 632, wherein the diametrical inner side and a diametrical outer side of the horizontal sealing plane 632 each form a shaft hole surface 634, which are formed around an outer periphery of the shaft hole 312 as a seal. A sealing recess 634a is formed on the shaft hole surface 634 and is provided on the diametrical inside.The shaft hole surface 634 is formed on the diametrically inner side, while the joining edge 633 and the inner surface 311 of the liner are connected to each other to form a complete sealing surface 6. Reinforcing parts 318 are formed on the diametrically outer side of the horizontal sealing plane 632, each of which is provided on two sides of the shaft hole 312 and arranged along a central axis 25. The width of the reinforcing part 318 is twice the thickness 631(t1) of the inner metallic throttle plate 51 of the throttle plate 5, in order to solve the problem of the joining edge 633 running out with the smooth variations in the thicknesses of the horizontal sealing plane 632 and the tubular part 31. The central axis 25 is an axis perpendicular to the axial direction and passing through a center of the shaft hole 312.

[0085] The Fig. 3 shows that the backup ring 4 is an elastic body made of rubber and installed between the groove 232 of the inner peripheral surface 23 of the valve stem 2 and the tubular part 31 of the fluororesin liner 3. A stem hole part 46 is arranged as required by a valve shaft 55 of the throttle plate 5. An inner diameter 41 of the backup ring 4 basically corresponds to an inner diameter of the valve stem 2. When the backup ring 4 is inserted into the groove 232, an expansion space 235 is formed to accommodate thermal expansion at high temperatures. When the backup ring 4 is firmly pressed, more than 80 percent (80%) of the expansion space 235 can be filled, and the entire space can be filled by thermal expansion at high temperatures. The outer diameter 315 of the tubular part 31 basically corresponds to the inner diameter of the valve stem 2.The inner diameter 41 of the support ring and the inner surface 311 of the liner is slightly smaller and protrudes inward due to shrinkage during the manufacturing process. A thickness 45(s3) of the support ring together with the height 239(s2) of the protruding ring 234 corresponds to the depth 237(s1) of the groove 232. Due to the shrinkage and deformation occurring during the manufacturing process, the thickness 45(s3) of the support ring 4 can be slightly increased, thereby slightly reducing the inner diameter of the support ring 4 compared to the inner diameter of the valve stem 2. The inner surface 311 of the liner also protrudes inward due to the above-mentioned shrinkage, creating a swelling curve 66a on the cross-section of the inner surface 311 of the liner. These arrangements require process control, with a swelling height 66b(h) being within a reasonable range.Since the installation of the throttle plate 5 in the tubular part 31 of the lining 3 requires a sufficient packing quantity 65(ε) to achieve a sealing effect, the swelling height 66b(h) must be controlled and taken into account during the manufacturing process in the calculation of the packing quantity 65(ε). Fig. Figure 5A shows the packing quantity 65(ε).

[0086] The Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D shows that the throttle plate 5 is formed in the shape of a disc, wherein the throttle plate 5 has an outer edge 53 of the throttle plate. The outer edge 53 of the throttle plate has an annularly curved surface 531. Two axial ends of the throttle plate 5 each form a horizontal sealing end surface 635. The horizontal sealing end surface 635 is formed corresponding to the horizontal sealing plane 632 of the liner 3. The horizontal sealing end surface 635 and the annularly curved surface 531 are connected to each other, wherein the connection forms a lateral cutting edge 636 and is formed in an arc shape. The lateral cutting edge 636 is formed corresponding to the joining edge 633, which is formed on the diametrically inner side of the liner 3 for sealing. The horizontal sealing face 635 and the horizontal sealing plane 632 are pressed axially and vertically against each other for sealing.The seal between the lateral cut edge 636 and the joining edge 633 is changed from a vertical seal to a radial seal. Since the thickness is smoothed with the reinforcing part 318, the tight pressing is uniform, so that no fluid leaks from the valve shaft 55. A protruding part 54 and the valve shaft 55 are arranged on the horizontal sealing face 635. The valve shaft 55 and the protruding part 54 are concentric. The valve shaft 55 consists of a long upper valve shaft 55a and a short lower valve shaft 55b. The valve shaft 55 passes through two shaft holes 312 of the liner 3 and is inserted into the shaft hole part 212 of the upper valve stem 21 and the shaft hole part 222 of the lower valve stem 22, so that the throttle plate 5 can be rotated to adjust the flow rate or to open and close the valve.The protruding parts 54 divide the throttle plate 5 into two throttle plate flanks 56. The throttle plate flank 56 can have a plate-like cross-section or a conical cross-section. For example, a large throttle valve as shown in FIG. Fig. 7E has a conical cross-section, while a small throttle valve has a plate-like cross-section (see Fig. 4A).

[0087] An outer diameter of the outer edge 53 of the throttle plate of the throttle plate 5 is slightly larger than an inner diameter of the inner surface 311 of the liner, with half of the difference as shown in the Fig. 5A, between these is the packing quantity 65(ε) for a unilateral radius. A compression ratio of the sealing surface 6 is a number of the packing quantity 65(ε) in comparison with the thickness 45(s3) of the support ring 4. Depending on the material used for the support ring 4 and the requirement for pressure resistance and temperature resistance, the compression ratio ranges from 15 percent (15%) to 22 percent (22%), whereby with the thickness 631(t1) of the metallic throttle plate 51 at the outer edge of the throttle plate flank 56, a complex seal with a sealing width can be achieved, and this sealing width is greater than or equal to 4 mm, ie ≧4 mm, while as in the Fig. 4A shows a 3-inch throttle plate as an example.

[0088] The Fig. 1 shows that a protruding seal ring 637a is arranged on a shaft sealing surface 637 of the protruding part 54 of the horizontal sealing face 635. The sealing recess 634a of the shaft hole surface 634 can be sealed with this protruding seal ring 637a, and an outer diameter of the protruding part 54 can be reduced. Therefore, the seal between the outer edge 53 of the throttle plate and the inner surface 311 of the liner is also attached to the shaft sealing surface 637 and the shaft hole surface 634 to form a continuously reliable sealing surface 6, including the seal between the horizontal sealing face 635 and the horizontal sealing plane 632.

[0089] The Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D show that the outer edge 53 of the throttle plate has a complex sealing structure 67 that is resistant to high temperatures and high pressure, achieves low torque, and has a long service life. The complex sealing structure 67 consists of the annular curved surface 531 of the outer edge 53 of the throttle plate, wherein this annular curved surface 531 is a smooth curved surface with a conical surface of unequal width 532 and with a curved surface of unequal width 533. The curved surface of unequal width 533 is as shown in the Fig. 5D shown in a closing direction 791 of the throttle plate 5. The respective positions along the cross sections aa, bb and cc correspond to the positions of the cross sections of the Fig. 7A. A part of the unequal-width conical surface 532 along section aa has a smaller sealing width 63(B), a part of which along section bb has a larger sealing width 63(B), while a part of which along section cc has the largest sealing width 63(B). In other words, the structure progressively widens from the part near the valve shaft 55 to the part near the central part of the throttle plate 5, while the unequal-width conical surface 532 is constructed as a part of the sealing surface 6. With a side of the unequal-width conical surface 532 opposite the curved surface 533, a corner edge 535 is formed which has a small radius of curvature, and this small radius of curvature is fixed to a surface of the throttle plate flank 56.The corner edge 535 is arranged in an opening direction of the throttle plate 5. Extremely low interference sliding 7 occurs with the corner edge 535 and the inner surface 311 of the liner. The uneven-width curved surface 533 extends from the surface of the throttle plate flank 56 to the outer edge 53. The part of the uneven-width curved surface 533 along section aa has a longest smooth arc 533a, its part has a shorter smooth bottom 533b along section bb, while its part has a shortest smooth arc 533c along section cc, in other words, the structure is progressively tapered from the part close to the valve shaft 55 to the part close to the central part of the throttle plate 5. The uneven-width curved surface 533 has an interference sliding 7 with the inner surface 311 of the liner.The longest smooth arc 533a, the shorter smooth arc 533b, and the shortest smooth arc 533c are formed into a curve analogous to an elliptic curve. The short diameter of the ellipse is perpendicular to the surface of the throttle plate flank 56. These curves can be formed into multiple arcs. An outer edge 511 of the inner metallic throttle plate 51 of the throttle plate 5 also has a corresponding curved structure, including the throttle plate flanks 516, the protruding parts 517, the horizontal sealing faces 518, and the side cutting edges 519 (see ). Fig. 4D). A conical surface of unequal width 514 is also provided, with a curved surface of unequal width 515 having a longest arc 515a along cross-section aa and a shortest arc 515c along cross-section cc.

[0090] The Fig. Figure 4A shows that the complex sealing structure 67 can ensure resistance to high temperatures and high pressure. Here, for a throttle valve with a caliber of 3 inches, the thickness of the outer edge of the metallic throttle plate 51 is 8 mm, and the sealing width 63(B) of the uneven-width portion of the tapered surface 532 along the cross-section aa is greater than 50 percent (50%) of the outer edge thickness 631(t1) of the inner metallic throttle plate 51, while its sealing width is over 4 mm. Furthermore, the sealing width 63(B) of the uneven-width portion of the tapered surface 532 along the cross-section cc is greater than 70 percent (70%) of the outer edge thickness 631(t1) of the inner metallic throttle plate 51, while its sealing width is over 5.6 mm.The conical surface of unequal width 532 and the inner surface 311 of the liner are pressed against each other to form a continuously reliable sealing surface 6, the seal being as shown in the . Fig. 2A and Fig. 4C, is also attached to the shaft seal surface 637 and the shaft hole surface 634. The seal surface 6 has the largest radius and bears the largest static pressure moment at the part along the cross section cc to achieve the largest seal width 63(B), ensuring higher pressure resistance and better airtightness. This seal width 63(B) is not less than the width of the prior art band seal 62.

[0091] The Fig. 5Ai, Fig. 5Aii, Fig. 5Aiii show that the Fig. 4A to 4D can satisfy the low torque and have a long service life because the part of the curved surface with unequal width 533 along the cross section aa has a smaller contact angle 71(θ) and significantly shortens the sliding distance, and the contact angle 71(θ) of the curved surface with unequal width 533 approaches the contact angle 71(θ) of the linear seal according to the prior art.

[0092] The Fig. 5Ai, Fig. 5Aii, Fig. 5Aiii, Fig. 5B, Fig. 5C, Fig. 5D and Fig. 5E show that the Fig. 4A to 4D can meet the low torque and have a long service life. Specifically, considering the part of the complex seal structure 67 along the cross section aa during closing, an interference sliding 7 is generated between the unequal-width curved surface 533 and the inner surface 311 of the liner, while the unequal-width curved surface 533 slides forward by a sliding angle 74(ψ) to allow a frictional force 75(F) to act on the inner surface 311 of the liner, causing a depression at a location to which the pressure is applied, and resulting in deformation of the liner 68(δ) projecting forward on a front side of the outer edge 53 of the throttle plate. The material of the inner surface 311 of the liner has the deformation of the liner 68(δ) which resists the pressure, the size of the deformation being different depending on the value of the packing quantity 65(ε).The material of the inner surface 311 of the liner on the back of the outer edge 53 of the throttle plate resists stress. The sliding angle 74(ψ) and the deformation of the liner 68(δ) of the complex seal assembly 67 are smaller than those of the band seal 62 and the linear seal 61. As the sliding angle 74(ψ) and the deformation of the liner 68(δ) increase, they become less suitable for use at high temperatures. In other words, greater creep and greater friction forces 75(F) occur on the materials of the inner surface 311 of the liner and the external fluoroplastic encapsulation 69 of the throttle plate 5.

[0093] The Fig. 6A shows that the throttle plate 5 is opened or closed, with the throttle plate 5 forming a certain opening angle, and a gap passage 81 is formed with a flow channel 8, while a rapidly expanding flow channel 814 and a gradually reducing flow channel 815 are each created on either side of the throttle plate 5, as indicated by a streamline 811 in the figure with an arrow. When the fluid flows, a circulation zone 812 appears on the back of the throttle plate 5. With the curved surface of unequal width 533 of the outer edge 53 of the throttle plate of the throttle plate 5, the gap passage 81 can be formed with more flow areas, that is, a gap width 813(W) is increased. This arrangement promotes an increase in flow rate and an increase in the Cv value of the throttle plate 5 in a small-angle position, and also reduces a torque converter 792(Th).

[0094] The closing torque of the throttle valve of the present invention is less than 40 Ntm of atmospheric pressure, which is required when using a 3-inch throttle valve and setting it at a position of nearly 90 degrees. A torque of less than 30 Ntm (<30 Ntm) is required from 0 degrees to 80 degrees, while a torque of less than 20 Ntm (<20 Ntm) is required during opening. These results show that the interference sliding 7 occurring smoothly on the inner surface 311 of the liner and the friction force 75(F) are reduced. In particular, by reducing the required opening torque, the friction force 75(F) is significantly reduced, extending the service life of the throttle valve 1.

[0095] In a preferred embodiment of the present invention, tests are conducted on a standard platform. The angles of the throttle disc 5 are set to 0 degrees, 18 degrees, 36 degrees, 54 degrees, 72 degrees, and 90 degrees. If the angle is 0 degrees, a fully open state exists. If the angle is 90 degrees, a fully closed state exists. Table 1 shows a result of the preferred embodiment, which shows the flow coefficient Cv. Table 2 shows a result of Reference 10, which shows the Cv value, while Table 3 shows a result of Reference 11, which shows the Cv. The Fig. 6Bi, Fig. 6Bii and Fig. 6Biii are graphs showing curve A, curve B, and curve C with different opening angles. The comparison between the throttle valve of the present invention and these two references is described as follows: 1. The linearity of the flow coefficient Cv curve of the throttle disk of the present invention is better than that of Reference 10 and Reference 11. 2. The flow coefficient Cv% is 16% when the throttle plate of the present invention has a small angle of 36 degrees. The Cv% is 9% when the reference 10 has an opening angle of 35 degrees. The Cv% is 11% when the reference 11 has an opening angle of 40 degrees. 3. The flow coefficient Cv% is 34% when the throttle plate of the present invention has an average opening angle of 54 degrees. The Cv% is 23% when the reference 10 has an opening angle of 55 degrees. The Cv% is 26% when the reference 11 has an opening angle of 60 degrees. Table 1 3"-ausgekleidetes Drosselventil (Ausführungsbeispiel) Öffnungswinkel 0 18 36 54 72 90 Cv 0 10,7 60,3 127,2 271 377,2 Cv% 0% 3% 16% 34% 72% 100% Table 3 Referenz 11 Tomoe-Ventile USA-Katalog-846t-847t-847q-20150601 ausgekleidetes 3 Drosselventil Öffnungswinkel 0 20 30 40 50 60 70 80 90 Cv 0 9 25 56 85 130 225 396 500 Cv% 0% 2% 5% 11% 17% 26% 45% 79% 100% List of reference symbols 1 Symmetrical throttle valve 2 valve stem 21 Upper valve stem 211 Fastening part 212 Shaft hole part 22 Lower valve stem 221 Fastening part 222 Shaft hole part 23 Inner peripheral surface 232 groove 233(γ) Trapezoidal included angle 234 Protruding ring 235 expansion space 236(t2) Width of the protruding ring 237(s1) Groove depth 238(t3) Lower width 239(s2) Height of the protruding ring 24 mounting holes 25 Central axis 3 lining 31 Tubular part 311 Inner surface of the lining 312 shaft hole 315 outer diameter of the tubular part 318 Reinforcing part 32 Radial flange 4 support ring 41 Inner diameter of the support ring 42 Trapezoidal cross-section 43(α) Trapezoidal included angle 45(s3) thickness 46 Shaft hole part 5 Throttle disc 51 Metallic throttle plate 511 outer edge 513 connecting hole 514 Conical surface with unequal width 515 Curved surface with unequal width 515a Longest Arch 515c Shortest Bow 516 throttle plate flank 517 Preceding part 518 Horizontal sealing face 519 Side cutting edge 53 Outer edge of the throttle disc 531 Ring-shaped curved surface 532 Conical surface with unequal width 533 Curved surface with unequal width 533a Longest even arch 533b Shorter even arch 533c Shortest regular arc 54 Preceding part 544 shaft hole 55 valve shaft 55a Upper valve shaft 55b Lower valve shaft 56 Throttle disc flank 57 Outer diameter of the throttle plate 6 Sealing surface 61 Linear Seal 62 band seal 63(B) Sealing width 631(t1) Thickness of the metallic throttle plate 632 Horizontal sealing plane 633 joining edge 634 shaft hole area 634a Sealing recess 635 Sealing face 636 Side cutting edge 637 Shaft sealing surface 637a sealing ring 64(p) Press pressure 65(ε) Packing quantity 66 projection inwards 66a Source curve 66b(h) source height 67 Complex sealing 68(δ) Deformation of the lining 69 Fluoroplastic encapsulation 69a Deformation of the encapsulation 7 Interference glide 71(θ) contact angle 72 Contact point 73(R) Rotating lever arm 74(ψ) Glide angle 75(F) Frictional force 79(T) torque 791 Direction of rotation 792(Th) torque converter 793(Tp) Torque of static pressure 794(Tf) Friction moment 8 flow channel 81 gap passage 811 Streamline 812 Circulation zone 813(W) gap width 814 Strongly expanding flow channel 815 Gradually reducing flow channel 82(Ps) Static pressure 9 Fluoroplastic throttle valve 91 Valve stem 911 Inner peripheral surface 912 groove 913 Upper shaft hole part 914 Lower shaft hole part 92 throttle plate 92a Throttle disc of the linear seal 92b Band seal of the throttle plate 92c Metallic throttle plate 921 throttle plate flank 922 Outer edge of the throttle plate 923 Ring-shaped curved surface 923a angle 924 Conically curved surface 927 throttle disc projection 928 shaft hole 929 Diametrical connection 93 lining 931 Tubular part 932 Radial flange 933 Inner surface of the lining 937 shaft hole 94 support ring 941(t4) thickness 95 valve shaft

Claims

[1] A fluoroplastic throttle valve assembly comprising: a valve stem (2); and a throttle disc (5) which is pivotally connected to the valve stem (2) by a valve shaft (55); the valve stem (2) is opened or closed with the throttle disc (5) by rotating the valve shaft (55); wherein a throttle plate (5) has an outer edge of the throttle plate (53); the outer edge of the throttle plate (53) has an annularly curved surface (531); the annularly curved surface (531) has an unequal-width conical surface (532); a sealing width (63(B)) of the unequal-width conical surface (532) gradually widens from the valve shaft (55) to a central part of the throttle plate (5); a sealing width (63(B)) of a part of the unequal-width conical surface (532) near the valve shaft (55) is 50 percent (50%) larger than a thickness of an outer edge (511) of an inner metallic throttle plate (51); a sealing width (63(B)) of a portion of the conical surface of unequal width (532) near the central portion of the throttle disc (5) is 70 percent (70%) greater than the thickness of the outer edge (511) of the metallic throttle disc (51). [2] The structure of the fluororesin throttle valve according to claim 1, wherein the annular curved surface (531) is further composed of a complex sealing structure including a curved surface of unequal width (533) and a tapered surface of unequal width (532); the curved surface of unequal width (533) extends from a surface of the throttle plate (5) to the outer periphery of the throttle plate; a smooth arc of the curved surface of unequal width (533) is gradually tapered from a valve shaft (55) to the central part of the throttle plate (5); the curved surface of unequal width (533) is arranged in a closing direction of the throttle plate (5).

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