Lined valve with improved diaphragm sealing mechanism

Abstract

This invention relates to an ultrapure lined valve for the transport of ultrapure chemicals, hereinafter referred to as the liner valve. The liner valve consists of a drive unit, a valve body, and a sealing mechanism. The sealing mechanism, which requires high cleanliness, includes a diaphragm made of materials such as PFA and PTFE. The diaphragm blocks the flow of fluid through reciprocating motion. This invention improves the sealing function of one circumferential portion of the diaphragm by incorporating hydrostatic sealing and tensile sealing. The purpose is to prevent the diaphragm from failing. If the seal fails, the chemical solution will diffuse through the failed sealing interface and react with the metal part of the valve body to generate metal ions. These metal ions will then permeate back and contaminate the chemical solution. The patent features include: the valve body has an annular portion, which includes a sealing liner, a sealing seat, a diaphragm groove, and an internal thread; the sealing liner is connected to a liner of the valve body to form a whole; the sealing mechanism includes the sealing seat, the diaphragm groove, the sealing liner, the diaphragm, a diaphragm gasket, a clamping ring, a pressure ring, and a holding nut; the holding nut includes an external thread, an annular groove, and a support ring; the external thread can be tightly locked to the internal thread; the annular groove can accommodate the pressure ring and has a radial clearance; the diaphragm includes a blocking portion, an elastic portion, and a circumferential portion, the circumferential portion including a clamping groove. The clamping groove can be installed in the diaphragm groove on the sealing seat; the clamping ring, which has a rectangular radial cross-section and includes pointed ends, is installed in the clamping groove and extends more than half of its length; the pressure ring is installed in the annular groove to fix the extended part of the clamping ring, and there is an axial gap between the pressure ring and the diaphragm groove; the sealing liner, the clamping groove, the clamping ring, the pressure ring, etc., form a combined elastic body under clamping. When clamped, the combined elastic body is supported by the metal structure of the annular part, the sealing seat and the support ring, and can generate sufficient deformation pressure while maintaining a low compression ratio to ensure a high reliability seal of the sealing surface.

Description

Technical Field

[0001] This invention refers to a valve that uses diaphragm deformation and reciprocating displacement to block the flow of fluid inside the valve body, called a diaphragm valve, including globe valves and membrane valves. Its characteristics include a drive unit, valve body, diaphragm, diaphragm gasket, and sealing mechanism. The valve body includes a valve seat, valve chamber, inlet flow channel, and outlet flow channel; the diaphragm has a blocking part, an elastic part, and a circumferential part. The blocking part seals the valve seat to block fluid flow, and the circumferential part has a circumferentially projecting downward axial ring. The inner diameter of the axial ring is larger than the inner diameter of the valve chamber to seal it; the diaphragm gasket is made of rubber to bear the pressure inside the valve chamber, preventing the thin diaphragm from deforming or breaking under pressure. The sealing mechanism consists of the upper flange of the drive unit and the lower flange of the valve body, which are locked together to force the circumference of the diaphragm. In some cases, the outer circumference of the diaphragm gasket is forced to seal together with the circumference of the diaphragm, thus the outer circumference of the diaphragm gasket and the circumference of the diaphragm can be regarded as a combined elastic body. The valve seat of the gate valve is annular and connected to the inlet flow channel. The blocking part is located in the center of the diaphragm and is cylindrical, which can block and seal the valve seat. The valve seat of the diaphragm valve is a transverse weir. The blocking part is a horizontal sealing line in the center of the diaphragm, which can block and seal the weir separating the inlet flow channel and the outlet flow channel. Moreover, the circumference is equipped with a circular annular sealing line with a protruding semicircle. The horizontal sealing line runs through and connects the annular sealing line. The inner diameter of the annular sealing line is larger than the inner diameter of the valve chamber. Prior Technology

[0002] Rubber flange gaskets and O-rings are known to have a complete 3D molecular structure with good deformation and elastic coefficient k-value, enabling them to have effective sealing performance. The sealing mechanism of diaphragm valves uses rubber diaphragms that can be stretched several times and still return to their original characteristics. Under appropriate sealing surface pressure, the complete 3D molecular structure can withstand more deformation and rarely experience material creep. However, the failure risks of rubber materials include the fact that their k-value will decrease under high temperature, reducing the sealing interface pressure. Secondly, rubber materials are not corrosion resistant and can also experience fatigue failure under excessive pressure. All of these factors can cause the sealing mechanism of diaphragm valves to fail and leak.

[0003] When diaphragms are made of fluorinated materials such as PFA and PTFE, their molecular structure consists of linear long-chain molecules with weak 3D structural linkages. This results in three main characteristics: First, they cannot provide the deformability of rubber. Second, while they possess high ductility (up to 300%), they are prone to material migration hardening and cannot recover their original dimensions and properties. In other words, their material elasticity is poor, limited to low elongation or low compressibility. Third, when the diaphragm is subjected to excessive tension, material migration hardening occurs, and when the material is subjected to excessive compression, material creep also easily occurs. This means that the material easily loses elasticity and strength under pressure, but is not prone to compressive fatigue failure.

[0004] When the diaphragm of a diaphragm valve is subjected to pipeline pressure, pressure waves, and reciprocating displacement, the elastic part of the diaphragm will deform and apply tension to the circumference of the diaphragm. During the continuous tensile process, the material of the circumference will migrate due to the continuous tensile force, leading to the failure of the forced seal. In particular, when the diaphragm is subjected to reciprocating displacement, in addition to the tensile force, the circumference will also be subjected to instantaneous and drastic pressure changes, resulting in a breathing effect, which aggravates the back diffusion of contamination. This simultaneous tensile force and breathing effect constitutes a tensile seal, which may cause interface leakage and interface diffusion.

[0005] When a diaphragm valve is used to connect lined steel pipes made of PFA, PTFE, or other lined materials and is applied to the transportation of ultrapure hydrofluoric acid, high-purity liquids, etc., the diaphragm valve containing the lining is called a lined diaphragm valve, hereinafter referred to as a lined valve. When the sealing mechanism of the lined valve fails, the chemical liquid leaks through the diaphragm sealing interface and reacts with the metal of the external valve body to produce metal ion contaminants. These metal ion contaminants will then diffuse backward through the diffusion effect and contaminate the chemical liquid. However, in most environments where ultrapure chemical liquids are not required, such trace contamination from backward diffusion is negligible.

[0006] In semiconductor manufacturing processes below 3 nanometers, liquid delivery pipelines are extremely vulnerable to even the slightest contamination, as the contamination level must be reduced to at least the ppt level. In particular, the sudden and intense breathing action can exacerbate back-diffusion contamination, which is a serious issue for the delivery of high-purity pharmaceutical solutions. Therefore, improving the high reliability of the sealing mechanism of diaphragm valves has become a key focus of improvement. The aforementioned challenge of extremely high sealing reliability must be met by passing leakage testing requirements, including room temperature leakage testing and high temperature leakage testing.

[0007] The physical phenomena of leakage in the sealing mechanism of a diaphragm valve include interfacial leakage and interfacial diffusion:

[0008] Interface leakage: The sealing interface of a pipeline refers to the interface seal between two rigid flanges or similar structures and a combined elastomer. The sealing interface length is L. Chemical liquid will flow in the tiny gaps (size d) that are not filled in the sealing interface. Eventually, the chemical liquid will be pressurized and flow out through the sealing interface. The more the combined elastomer deforms and the higher the compressive pressure, the smaller the size d of the tiny gap. However, the compressive pressure cannot be too high, otherwise fatigue failure will occur and leakage will occur. Under long-term pressure, the combined elastomer will also undergo creep and deformation, which will reduce the compressive pressure. When interface leakage occurs, the chemical liquid has the potential to corrode the diaphragm gasket, causing the sealing interface pressure to decrease further and the leakage to deteriorate.

[0009] Interface diffusion: When interface leakage occurs, it means that the micro-gap has been opened. If the chemical solution reacts with the metal of the external valve body and produces a high concentration of metal ions, the high concentration of metal ions will diffuse in reverse along the opened micro-gap. In the end, these metal ions will contaminate the ultra-clean chemical solution in the pipeline. When the diaphragm valve opens and closes, the breathing effect will accelerate the reverse interface diffusion and accelerate the contamination.

[0010] Breathing action: This refers to the rapid reciprocating motion of the diaphragm when it is driven by a pneumatic cylinder or electric coil. In addition to the tension, the valve chamber is also subjected to sudden and drastic pressure changes. When the pressure rises or falls instantaneously, it will exacerbate the diffusion of contaminants at the reverse interface.

[0011] The sealing mechanism of a diaphragm valve must withstand the static pressure in the pipeline and the tensile force when the diaphragm deforms, i.e., static pressure sealing and tensile sealing, as explained below:

[0012] Static pressure seals: The pipeline pressure and pressure waves they need to withstand only need to pass a normal temperature leak test. The focus is on the tightening pressure and sealing length after the sealing interface is deformed under pressure. Secondly, without requiring high-purity chemical solutions, most static pressure seals, even with PPT level, will generate metal ion contamination externally when micro-leaks occur. However, most of this contamination will be discharged into the external environment, and the trace amount of reverse diffusion contamination is not a concern. In addition, it is necessary to avoid excessively high sealing interface pressure, which could cause material fatigue failure of the combined elastic body.

[0013] Tensile sealing: The circumference of the diaphragm needs to withstand pipeline pressure and pressure waves, as well as the deformation and tension of the elastic part, and also the reverse diffusion contamination generated by respiration. The key points are the tightening pressure after the sealing interface is deformed by pressure, the sealing length, and the obstruction of respiration. In most environments where ultra-high purity of the liquid is not required, the trace contamination caused by respiration is ignored. However, under the transportation of high-purity chemical liquids, the trace contamination caused by reverse diffusion and respiration becomes the focus of prevention and control.

[0014] The above discussion can be summarized into the following description of the structural characteristics of a high-reliability sealing mechanism:

[0015] High-reliability sealing: The strength of the sealing gasket (e.g., diaphragm), the elastic coefficient K value, and the gasket thickness t under compression force will also be compressed and deformed simultaneously, Δt. The magnitude of the compression pressure is proportional to the values ​​of K and Δt. Secondly, the elastic coefficient K value of the sealing gasket will gradually decrease over time, and the compression pressure will also decrease synchronously. When the compression pressure is appropriate and the compression ratio or elongation of the sealing gasket is lower, the elastic coefficient K value of the sealing gasket is less likely to decay and fatigue failure. Furthermore, the lower the compression ratio or elongation, the less likely material creep will occur, resulting in a longer service life. When the size d of the micro-gap at the sealing interface is equal to the length L of the sealing interface, the length-to-scale ratio is L / d. The larger the length-to-scale ratio, the lower the leakage and the greater the risk of reverse diffusion of metal ions.

[0016] High-temperature leakage test: The PTFE membrane and related clamping mechanism are baked at high temperature for more than 9 hours at 180°C. After cooling, the same room temperature leakage test is performed. The high-temperature baking accelerates the deformation and shrinkage of fluorinated materials such as PTFE and PFA to represent the material creep. If there is still a low leakage, it means that the creep risk is reduced. This is a tensile seal test method, which includes the leakage reliability under positive pressure and the reverse diffusion leakage reliability under breathing effect.

[0017] The conventional lined valve comprises: a drive unit, a valve body, a diaphragm, a diaphragm gasket, and a sealing mechanism.

[0018] The drive unit includes a central shaft, a lifting mechanism, and a valve cover; the valve cover includes an upper flange.

[0019] The valve body includes: a metal body, a liner, an inlet flow channel, a valve chamber, a valve seat, an annular flow channel, an outlet flow channel, and a lower flange.

[0020] The lower flange includes a sealing seat and a diaphragm groove; the upper flange and the lower flange together form a sealing flange, and the sealing interface of the sealing flange of a conventional diaphragm valve is an annular plane.

[0021] The lining is made of fluorinated materials such as PFA and PTFE. The lining covers the entire valve body, including the inlet flow channel, valve chamber, valve seat, annular flow channel, outlet flow channel, and lower flange, and includes the sealing seat and diaphragm groove of the lower flange, forming the flange sealing interface.

[0022] The diaphragm includes a blocking portion, an elastic portion, and a circumferential portion.

[0023] The diaphragm gasket is made of rubber, and its outer diameter is equal to the outer diameter of the diaphragm and includes an outer circumference.

[0024] The sealing mechanism includes the circumferential portion and the outer circumference. The upper flange and the lower flange are tightened by locking bolts to compress the circumferential portion and the outer circumference to achieve a seal. The circumferential portion and the outer circumference can be regarded as a combined elastic body.

[0025] From the above discussion, it can be seen that a high-reliability seal for this sealing mechanism must meet the following requirements:

[0026] Requirement 1: Sealing interface pressure. Maintain an appropriate sealing interface pressure, which should be greater than the valve chamber pressure, to meet the requirement of reducing static pressure leakage. The pressure of this combined elastomer should not be too high, as this may lead to fatigue failure.

[0027] Requirement 2: Low compressibility. The circumference contains a low compressibility. When compressed, the larger the volume of the combined elastomer, the easier it is to maintain a low compressibility and the less likely it is to experience material fatigue and creep.

[0028] Requirement 3: Tensile strength. The circumference includes a tensile strength structure to reduce material migration at the sealing interface, as material migration at the sealing interface reduces the sealing pressure and increases the risk of leakage.

[0029] Requirement 4: Seal length, increase the actual length L of the sealing interface and compress the size d of the sealing gap, a higher length-to-scale ratio, L / d. A larger length-to-scale ratio can reduce leakage and extend the time and amount of reverse diffusion pollution.

[0030] In addition to meeting requirements 1 (sealing interface pressure), 2 (low compression ratio), 3 (tensile strength), and 4 (sealing length), the sealing mechanism also needs to pass both room temperature leakage tests and high temperature leakage tests. The lower the leakage, the higher the sealing reliability of the sealing mechanism.

[0031] Most conventional lined valves do not consider the requirements for ultra-clean liquid delivery. Although most conventional solutions can pass the normal temperature leakage test under static pressure, they often fail the high temperature leakage test and cannot simultaneously meet requirements one, two, three, and four. Several reference solutions for conventional lined valves have been proposed. The following are reference solutions for conventional technology:

[0032] Case Study 1

[0033] Chinese Patent CN110168262B (2021) – Gasket and Seal Construction – describes a sealing device for special seawater applications. It is a variation of the conventional O-ring structure, incorporating a horizontal ring and an axial ring on the inner diameter side, giving it an L-shaped cross-section. The all-rubber structure itself is the combined elastomer. The horizontal ring isolates the external seawater, while the axial ring performs the sealing function of the original O-ring groove. The aim is to prevent corrosive seawater from accumulating in the annular groove of the sealing structure and corroding the flange. This design meets the requirements for room temperature leakage testing because rubber does not have creep issues, only material fatigue caused by long-term excessively high compression pressure. If the same structure is used as a structural reference for the circumferential portion of a diaphragm made of fluorinated materials such as PFA or PTFE, when the elastic part is connected to the inner diameter of the horizontal ring, the horizontal ring is prone to stretching, causing material migration and potential leakage risks. This design meets requirement one (sealing interface pressure) and requirement two (low compressibility). Requirement 4 (sealing length) cannot meet requirement 3 (tensile strength) because the planar structure is not conducive to tensile strength and cannot pass the high-temperature leakage test.

[0034] Reference Case 2

[0035] Japanese Patent JP2007224984A (2007) – Diaphragm valve: This is a diaphragm valve made of perfluorinated PFA and PTFE materials, suitable for applications with working pressures below 5 bar. The annular plane of the circumference of the diaphragm includes an axial ring for mounting on an annular sealing groove on the valve body. The drive unit of this reference includes a pressure ring installed inside the upper cover to compress the circumference of the diaphragm. Since the annular portion, pressure ring, and other structures are made of perfluorinated material, the combined elastomer includes the annular portion, pressure ring, and circumference. Both the valve upper cover and the valve body are four-cornered structures, secured by four metal bolts at the four corners. The combined elastomer experiences maximum sealing pressure around these four bolts. Although the metal bolts have a thin protective layer of fluorinated material, they are close to the sealing groove. When the circumference of the diaphragm is subjected to tensile force and material migration occurs, a slight... The chemical solution will create micro-leakage channels at the sealing interface and leak outwards. Furthermore, the actual length L of these micro-leakage channels is too short. These trace amounts of chemical solution will corrode the thin bolt protective layer and generate a large number of metal ions. These high-concentration metal ions will diffuse backwards along the micro-leakage channels into the valve chamber, contaminating the high-purity chemical solution. The locking mechanism of this reference design is concentrated on four metal bolts, and the entire structure is made of PFA material. Creep is easily generated around the high-strength metal bolts, which will lead to static pressure leakage after a period of time. This fails to meet requirement one (sealing interface pressure) because the sealing interface pressure near the bolts is not easily maintained uniformly, and also fails to meet requirement two (low compressibility) because the volume and length of the circumference are too short. Finally, it fails to meet requirements three (tensile strength) and four (sealing length). Because the circumferential structure is too short, it cannot pass the high-temperature leakage test; Chinese Patent CN204140937U-Engaged anti-leakage diaphragm valve (reference to this invention) is a lining diaphragm valve. The diaphragm has a thickness of t, the lining thickness is t, and there is a diaphragm gasket with a thickness of 5t on the air side of the diaphragm. The shortest sealing length of the circumferential part is 15t. The structure of this invention can meet requirement one (sealing interface pressure) and requirement two (low compressibility) because the thickness of the circumferential part of the diaphragm gasket is 5t. It cannot meet requirement three (tensile strength) because the planar structure is not conducive to tensile strength. It meets requirement four (sealing length) because the shortest sealing length is 15t. However, because the composite sealing gasket contains rubber material, it cannot pass the high-temperature leakage test.Chinese Patent No. CN_214146686_U-Steel lining diaphragm valve, 2021, describes a diaphragm valve with a diaphragm of thickness t, a lining of thickness 3t, and a diaphragm gasket of thickness 5t on the air side. The lining of the valve body extends to the sealing interface of the lower flange to form a lining sealing interface with a length of 12t. The thickness of the sealing material in the circumferential part of the sealing mechanism is 9t. The structure of this invention satisfies requirement one (sealing interface pressure) and requirement two (low compressibility) because the thickness of the sealing material is 9t. It fails to meet requirement three (tensile strength) because a planar structure is not conducive to tensile strength. It meets requirement four (sealing length) because the shortest sealing length is 12t. However, because the composite sealing gasket contains rubber material, high-temperature leakage testing is not possible.

[0036] Reference Case 3

[0037] Japanese Patent JP2009236277A-DIAPHRAGM VALVE DEVICE (2009) relates to a diaphragm valve with a non-lined metal valve body and a metal structure, suitable for applications with low operating pressures below 5 bar. The focus is on the sealing structure of the circumferential portion of the diaphragm, which includes an elastic portion with a thickness of t and a relative radial length. A rectangular ring is included in the circumferential portion, which can be considered as a combined elastic body. The thickness of the rectangular ring is >5t, and its length is >6t. The outer surface of the rectangular ring has a fine raised ring ≤0.4t. When the rectangular ring is placed in the diaphragm groove of the valve body and is pressed by the valve cover, it has sufficient deformation space because the elastic portion is made into a shallow cup shape, which maintains a minimum elongation rate during the reciprocating motion of the diaphragm. The structure of this reference meets requirements one (sealing interface pressure), two (low compressibility), three (tensile strength), and four (sealing length). Because of the size and thickness of the rectangular ring and the low elongation structure of the elastic part, it can pass the static pressure leakage test, but cannot pass the high temperature leakage test.

[0038] Reference Case 4

[0039] Chinese Patent CN2466456Y-Diaphragm valve, issued in 2001, describes a conventional diaphragm valve with a PFA liner. The liner thickness is t, and it is suitable for a working pressure of 10 bar. The diaphragm is supported by a rubber diaphragm gasket on the air side. The gasket has an average thickness of 2t in the supporting portion. The elastic portion and circumferential portion of the diaphragm have an average thickness of t. The diaphragm and the diaphragm gasket are sealed together in the circumferential and outer circumferential portions, which can be considered as a combined elastic body. The valve is tightly sealed by the lower flange of the valve body and the upper flange of the valve cover. The flange includes a sealing interface with a minimum annular width of 5t. The flange is rectangular and sealed at its four corners by four bolts. The length of the sealing interface, from the valve chamber to the outer diameter of the flange, is also only 5t. The sealing interface pressure of the diaphragm is generated by the forced tightening of the combined elastomer. When excessive tightening pressure is applied, the rubber material of the combined elastomer is at risk of fatigue failure and leakage. When a small leak occurs, the chemical solution will react with the metal valve body, and some of the chemical solution will also corrode the rubber diaphragm gasket on the air side. Corrosion can also cause a drop in sealing interface pressure, leading to more leaks. Furthermore, high concentrations of metal ions generated from minor leaks can diffuse backwards along the leak path, contaminating ultra-clean chemical solutions. The structure of this reference design can meet requirements one (sealing interface pressure) and two (low compressibility) because the diaphragm gasket is 2t thick and the rubber's surface compression is 10%-15%. Maintaining the correct sealing interface pressure can prevent overpressure fatigue damage. However, as the working pressure increases, the sealing interface pressure also increases, posing a potential risk and failing to meet requirement three (tensile strength). This is because the diaphragm has an average thickness in the circumference and the sealing interface is planar. When the diaphragm is under pressure, the tensile force generated in the circumference will exacerbate the leak and cause more leaks, failing to meet requirement four (sealing length). The shortest length of the sealing interface is approximately 5t, located between the pressing surface of the upper flange and its outer diameter, and this position is precisely in the middle of the two locking bolts. Its high sealing reliability may be limited by the sealing length. This reference design can pass static pressure leak testing, but the rubber gasket cannot be tested for high-temperature leaks.

[0040] Reference Case 5

[0041] Chinese Patent CN217056430U (2022) – Leakage-proof tight diaphragm valve – addresses issues such as the diaphragm gasket being easily damaged and its elasticity (K-value) changing upon heating, leading to insufficient sealing interface pressure and leakage, including leakage and back-diffusion contamination. This patent focuses on improving the sealing mechanism used to seal the valve chamber. The sealing mechanism includes an upper flange, a lower flange, and a composite sealing gasket; the composite sealing diaphragm gasket includes a diaphragm and a diaphragm liner; the minimum width of the circumference is 10t. The purpose of the composite sealing gasket is to maintain a tight seal. The pressure at the sealing interface remains constant and does not decline; the diaphragm includes an elastic portion and a circumferential portion, both of which have a thickness of t; the diaphragm gasket includes a gasket elastic portion, a gasket circumferential portion, etc.; the outer diameter of the gasket circumferential portion is equal to the outer diameter of the flange; the thickness of the gasket elastic portion is 5t; the gasket circumferential portion includes the elastic sheet, the spacer ring, an outer circumference, etc.; the inner diameter of the elastic sheet is close to the inner diameter of the valve chamber; the outer circumference has a thickness of 2t and connects to the gasket elastic portion; the spacer ring and The elastic sheet is a hollow ring with an outer diameter equal to the outer diameter of the flange. The isolation ring is placed between the elastic sheet and the outer circumference. The thickness of the isolation sheet and the elastic sheet is t. The circumferential portion of the gasket is stacked together to form the combined elastomer. The purpose of the spacer ring is to homogenize the sealing pressure. The elastic sheet provides additional elasticity to ensure that the outer circumference of the rubber is free from compression fatigue failure, thereby preventing chemical leakage and reverse diffusion contamination of metal ions. The structure of this reference can meet requirement one (sealing interface pressure) and requirement two (low compressibility), but cannot meet requirement three (tensile strength) because the planar structure is not conducive to tensile strength. It cannot meet requirement four (sealing length) because the shortest sealing length is 10t. Moreover, once a micro-leak occurs, a high concentration of metal ions will be generated. Under the reverse diffusion and breathing effect, it is difficult to reduce the risk of pure chemical contamination. Secondly, the rubber material of the combined elastomer cannot avoid chemical corrosion and damage at high temperatures. The sealing mechanism cannot be tested for high-temperature leakage.

[0042] Reference Case Six

[0043] Chinese Patent CN203784359U (2014) – Combined pressing ring sealed diaphragm valve. This reference is a liner-lined diaphragm valve. The diaphragm gasket is composed of multiple layers of rubber rings located on the air side of the diaphragm's elastic portion. The purpose is to provide more uniform support to the diaphragm gasket under pressure, reducing deformation and ensuring average sealing pressure at the circumferential sealing interface, thereby improving leakage and sealing reliability. The thickness of the diaphragm in this reference is t, the thickness of the liner is 1.2t, and the thickness of the diaphragm gasket is 2t. The annular portion of the valve body includes a sealing interface with an inwardly recessed step. This sealing interface includes a PFA sealing liner connected to the liner of the valve body. The sealing interface, supported by the metal structure of the valve body, has a length of 1.2t. The outer diameter of the diaphragm liner is close to the inner diameter of the valve body. The elastic portion and the circumferential portion of the diaphragm maintain the same thickness t. The circumferential portion and the sealing liner can be considered as a combined elastomer with a thickness of 2t. The structure of this reference design can meet requirement one (sealing interface pressure) because the upper and lower flange faces can be tightly locked in the circumference. However, it cannot meet requirement two (low compressibility) because the thickness of the combined elastomer is 2.2t, which requires a relatively high compressibility and poses a potential creep risk. Therefore, it cannot meet requirement three (tensile strength) because the planar structure is prone to material migration, which is not conducive to tensile strength. Therefore, it cannot meet requirement four (sealing length) because the sealing interface length of the lower flange is only 1.2t, which is indeed too short to reduce the risk of leakage and reverse diffusion. Under tension and breathing, the risk of reverse diffusion of metal ions is too high. Although the diaphragm is forced to be tightly sealed at the sealing interface, it can be tested for high-temperature leakage. However, the sealing interface length of the circumference is only 1.2t and the thickness of the combined elastomer is only 2.2t, making it difficult to pass the high-temperature leakage test.

[0044] Reference Case Seven

[0045] Taiwan Patent No. TW202010966 (2020) – Diaphragm Valve Structure and Heat Source Isolation Method: This is a completely metal ion-free shut-off diaphragm valve made of perfluorinated material for applications at 200°C, operating at a pressure of 5 bar without diaphragm gasket support. The annular portion of the valve body is a deep cup shape and includes a diaphragm groove with a dimension of 4 tons. The diaphragm groove has a bottom support structure with a valve chamber wall thickness of 5t, a valve chamber plate of 5t, and multiple grid-like ribs for support. To isolate the high-temperature chemical liquid, the annular portion has a heat transfer limiting structure and grid-like ribs on its outer surface to provide additional structural strength support. The circumferential portion of the diaphragm includes an axial ring. The inner diameter of the axial ring has a stepped pressing surface and an insertion cylinder. The thickness of the elastic portion of the diaphragm is t, the radial thickness of the axial ring is 8t, the axial length of the pressing surface is 8t, the width of the diaphragm groove is 4t, and its depth is 4t. The sealing length is determined by… The distance from the inner diameter of the axial ring to the vent hole is calculated from the inner diameter of the diaphragm groove. The axial length of the insert of the axial ring embedded in the diaphragm groove is 12t. A tightening nut, made of fluorine material, is used to tighten the axial ring by threads coupled to the inner diameter of the annular portion. The front end of the tightening ring also includes an O-ring groove for mounting an O-ring. When the axial ring is under pressure, it is also supported by the outer wall of the annular portion, which is 6t thick, and multiple ribs. The structure of this embodiment is made of perfluorine material. The diaphragm groove, the circumferential portion, the annular portion, the ribs, the tightening nut, and the bottom support structure can all be considered as this group. The diaphragm has an Ω-shaped radial section when the valve is closed, and when the valve is opened, the Ω-shaped elastic part is pulled upward into an arc. The structure of this reference design satisfies requirement one (sealing interface pressure) because when the tightening nut tightens the axial ring in the diaphragm groove, the combined elastomers all bear the tightening force and simultaneously deform to maintain the sealing pressure. It also satisfies requirement two (low compressibility) because the structure of the combined elastomers all deforms together to form a structure that is not prone to creep, generating sufficient sealing pressure and significantly reducing the compression ratio. The compression ratio meets requirement three (tensile strength) because the structure of the axial ring is conducive to tensile strength and the Ω-shaped elastic part can also reduce tensile strength. It meets requirement four (sealing length) because the sealing interface length of the axial ring is >16t, which can indeed reduce the risk of leakage and reverse diffusion. Moreover, there is no metal ion generation from the external metal bolt part, so there is no risk of reverse contamination. It can not only conduct high temperature leakage tests but also pass the tests of leakage volume and pressure resistance. The overall structure of this reference is made of perfluorinated material, which cannot meet the high working pressure requirement of 10 bar for the liner valve.

[0046] Reference Case 8

[0047] Taiwan Patent No. TW202212719-Fluoropolymer Diaphragm Valve, this reference is a further improvement of reference seven. The thickness and Ω-shaped cross-section of the elastic portion of the diaphragm are improved to further reduce tensile force generated during pressure deformation. The thickness of the elastic portion near the circumference on the air side is increased, forming a groove-shaped axial ring. This axial ring has a wedge-shaped cross-section and a thickness of 3t. The axial ring is installed in the diaphragm groove of the annular portion. A bottom support structure of the diaphragm groove has a valve chamber wall thickness of 5t, a valve chamber plate of 7t, and multiple grid-like ribs for support. The clamping mechanism adds a clamping ring, which applies a clamping force F and a force angle ε to the axial ring during clamping. The force angle ε is the angle between the normal and the axial direction of the axial ring. The included angle of the clamping force F; the two ends of the clamping ring include a force point and a clamping point; a clamping nut, made of fluorine material, with threads coupled to the inner diameter of the annular portion to clamp the axial ring, when the axial ring is under pressure, it is also supported by the outer wall of the annular portion with a thickness of 6t and multiple annular ribs and vertical ribs, the clamping nut includes a groove and an inner ring, the groove located at the outer diameter of the front end of the clamping nut can be used to accommodate the clamping ring, the groove has a force point inside to apply pressure to the force point and clamp the axial ring by the clamping point; when the clamping ring is clamped, the inner ring provides inner diameter support, the outer side of the annular portion includes a radial rib support; the sealing length is the distance from the inner diameter of the axial ring and the inner diameter of the diaphragm groove to the breather hole, the shaft The axial length of the insert cylinder embedded in the diaphragm groove of the ring is >12t; such a sealing structure has higher strength than Reference 7 and a longer sealing length. The clamping force F and the force angle ε will ensure that the axial ring can reduce material migration when subjected to tensile force. The structure of the embodiment is made of perfluorinated material. The diaphragm groove, the circumferential portion, the clamping ring, the annular portion, the rib, the clamping nut, the bottom support structure, etc. can all be regarded as the combined elastomer. The structure of this reference can satisfy requirement one (sealing interface pressure) because the clamping nut, the clamping ring, and the axial ring can clamp and seal in the diaphragm groove. The combined elastomer all bear the clamping force and simultaneously deform to maintain the sealing pressure, satisfying requirement two (low compressibility) because the structure of the combined elastomer is all together. The deformation creates a structure that is not prone to creep, satisfying requirement three (tensile strength). This is because the structure of the axial ring is conducive to tensile strength, and the clamping force F and the force angle ε will ensure that the axial ring can reduce material migration when subjected to tensile force. Moreover, the Ω-shaped elastic part can also reduce tensile force, satisfying requirement four (sealing length). This is because the sealing interface length of the axial ring is >16t, which can indeed reduce the risk of leakage and back diffusion. Furthermore, there is no risk of metal ion generation from the external metal bolt part, thus eliminating the risk of back contamination. It can not only undergo high-temperature leakage testing but also pass the tests of leakage volume and pressure resistance. The overall structure of this reference design is made of perfluorinated material, which cannot meet the high working pressure requirement of 10 bar for the liner valve.

[0048] Based on the descriptions of the above eight reference cases, reference cases seven and eight in the prior art can simultaneously meet requirements one (sealing interface pressure), two (low compressibility), three (tensile strength), and four (sealing length), and can pass the high-temperature leakage test. The other reference cases cannot simultaneously meet the above four requirements and cannot pass the high-temperature leakage test. However, reference cases seven and eight do not have the problem of metal ion reverse diffusion contamination, and their working pressure is limited to 5 bar. But there is a working pressure requirement of 10 bar for lined valve applications. That is to say, the design of lined valves can draw on the structural concepts of reference cases seven and eight, but still needs to make different innovations in structure to meet the working pressure requirement of 10 bar. Summary of the Invention

[0049] This invention relates to a liner valve for transporting ultrapure chemicals. It improves the sealing mechanism for high cleanliness requirements, aiming to enhance the sealing function of the chemical liquid to prevent leakage of the chemical liquid through the sealing interface of the membrane and the generation of metal ion contaminants through metal reaction. These metal ion contaminants would then back-permeate and contaminate the chemical liquid through diffusion effect.

[0050] This invention is a continuation of Reference Case 8, Taiwan Patent TW-202212719 - Fluororubber Diaphragm Valve, with a working pressure of 5 bar, and inherits its sealing mechanism features. Further innovations are made to meet requirements 1, 2, 3, and 4 of the liner valve, and it passes both room temperature and high temperature leakage tests. Because the working pressure of the liner valve is 10 bar, the sealing method and structural strength of the sealing mechanism must be innovated and differ from Reference Case 8. Such innovation cannot be easily achieved through direct reference or conversion. When the sealing mechanism is supported by the metal structure of the valve body, the requirements for high-reliability sealing of the sealing mechanism will change as follows:

[0051] Requirement 1: Sealing interface pressure. Maintain appropriate sealing interface pressure to meet the requirement of reducing static pressure leakage. This requirement is easier to achieve for lined valves because they have metal structure support. However, increasing the working pressure to 10 bar will also increase the sealing pressure. If the sealing pressure is too high, it will increase the risk of diaphragm fatigue rupture.

[0052] Requirement 2: Low compressibility. The circumference contains a low compressibility. The larger the volume, the easier it is to maintain a low compressibility and the less likely it is to cause material fatigue and creep. The perfluorinated structure of Reference Case 8 can transmit the force F to the whole structure without easily causing creep. This requirement becomes difficult in lined valves because when the force F is applied, the metal structure of the valve body does not provide additional deformation to reduce the compressibility.

[0053] Requirement 3: Tensile strength. The circumference should include a tensile strength structure to reduce material migration at the sealing interface and thus reduce the risk of leakage. The thickness and Ω-shaped profile of the elastic part of the diaphragm in Reference Case 8 can already reduce the impact of tensile force on the circumference. This requirement becomes difficult in lined valves because the tensile force will still increase even with the Ω-shaped elastic part as the working pressure increases.

[0054] Requirement 4: Sealing length, increase the actual length L of the sealing interface, and a higher length-to-scale ratio, L / d. A larger length-to-scale ratio can reduce leakage and extend the time and amount of back diffusion contamination. This requirement becomes difficult in lined valves because the outer diameter of the diaphragm's circumference is a metal structure, which will greatly increase the risk of back diffusion contamination of metal ions.

[0055] A conventional liner valve consists of a drive unit, a valve body, a diaphragm, a diaphragm gasket, and a sealing mechanism.

[0056] The drive unit includes a central shaft, a lifting mechanism, a valve cover, etc.; the central shaft is connected to the diaphragm and the lifting mechanism drives the diaphragm to reciprocate to open or close the flow channel in the valve body; the lower opening of the valve cover includes an upper flange.

[0057] The valve body includes: a metal body, a liner, an inlet flow channel, a valve chamber, a valve seat, an annular flow channel, an outlet flow channel, and a lower flange.

[0058] The lower flange includes a sealing seat and a diaphragm groove; the upper flange and the lower flange together form a sealing flange, and the sealing interface of the sealing flange of a conventional diaphragm valve is an annular plane.

[0059] The lining is made of fluorinated materials such as PFA and PTFE. The lining covers the entire valve body, including the inlet flow channel, valve chamber, valve seat, annular flow channel, outlet flow channel, and lower flange, and includes the sealing seat and diaphragm groove of the lower flange, forming the flange sealing interface.

[0060] The diaphragm includes a blocking portion, an elastic portion, and a circumferential portion; the blocking portion includes a threaded hole for connecting to the central shaft, and the circumferential portion includes an axial ring, etc.; the axial ring is installed in the diaphragm groove.

[0061] The diaphragm gasket includes an outer circumference. When the outer circumference and the circumferential portion are forced together, it can be used to support the diaphragm to withstand high working pressure and prevent the diaphragm from deforming unevenly under pressure. Its outer diameter is equal to the outer diameter of the diaphragm.

[0062] The upper flange of the valve cover of the drive unit is mounted on the lower flange of the valve body.

[0063] The sealing mechanism is located on the lower flange and includes the sealing seat, the diaphragm groove, the diaphragm, the diaphragm gasket, etc. The upper flange and the lower flange are locked together by locking bolts to simultaneously compress the axial ring of the circumference of the diaphragm and the outer circumference of the diaphragm gasket. The axial ring and the outer circumference form a combined elastomer to achieve a highly reliable seal.

[0064] The patented features of the liner valve of this invention are improved from the above-mentioned conventional liner valves and include:

[0065] The valve body includes the metal body, the liner, the inlet flow channel, the valve chamber, the valve seat, the annular flow channel, the outlet flow channel, and an annular portion, etc.

[0066] The annular portion is open cup-shaped and includes the sealing seat, the diaphragm groove, the cup-shaped space, the lower flange, and also includes an internal thread and a sealing liner.

[0067] The sealing seat is a metal structure and is located on the inner diameter side of the bottom of the annular portion. The sealing seat is provided with the concave annular diaphragm groove.

[0068] The sealing liner is integrally connected to the liner of the valve body, and the sealing liner extends from the diaphragm groove surface at the bottom of the annular portion and terminates annularly at the internal thread.

[0069] The sealing mechanism is located in the annular portion and includes the sealing seat, the diaphragm groove, the sealing liner, the diaphragm, the diaphragm gasket, a clamping ring, a pressure ring, and a holding nut.

[0070] The radial section of the clamping ring is rectangular, with two pointed ends containing a force-bearing point and a clamping point, respectively.

[0071] The diaphragm includes the blocking portion, the elastic portion, the circumferential portion, etc.; the circumferential portion includes a clamping groove, which is a square groove including a first corner, a second corner, a third corner, etc., and these corners have high rigidity to prevent material migration when subjected to tensile force; the clamping groove can be installed in the diaphragm groove on the sealing seat; the clamping ring is installed in the clamping groove and extends more than half of its length.

[0072] The pressure ring has a rectangular cross-section, and its lower half includes a fixing groove with a rectangular opening. The fixing groove of the pressure ring can accommodate and fix the protruding part of the clamping ring. The fixing groove contains a force application point, and there is an axial gap between the pressure ring and the diaphragm groove.

[0073] The sealing liner, the clamping groove, the clamping ring, the pressure ring, etc., form a combined elastic body that is subjected to clamping.

[0074] The grip nut has a cross-section of an open cup-shaped metal structure with a central protrusion, including an external thread, a shaft hole, an annular groove, a support ring, an opening, multiple support ribs, and an inner chamber.

[0075] The holding nut, through its external thread, can be tightly locked to the internal thread of the annular portion, providing a downward clamping force F to compress the combined elastomer, causing deformation and achieving a highly reliable seal.

[0076] The diaphragm pad has an outer circumference containing a groove that is pressed by the end of the support ring to provide tension support for the diaphragm pad on the diaphragm. The outer diameter of the outer circumference is equal to the inner diameter of the pressure ring.

[0077] The annular groove has an inner opening with an outer diameter, and a pressure ring space is formed between the inner diameter of the annular portion and the support ring to accommodate the pressure ring. When the pressure ring is accommodated in the pressure ring space, a radial gap is left.

[0078] The shaft hole is located on the central protrusion of the holding nut and is used to accommodate the bearing and the central shaft of the drive unit. The outer diameter of the opening is the external thread. The plurality of support ribs connect the inner diameter of the opening and the outer diameter of the shaft hole to increase the structural strength of the holding nut.

[0079] The internal chamber is located at the front end of the holding nut and is used to accommodate the diaphragm gasket, the blocking part of the diaphragm, and the related connecting structures of the central shaft.

[0080] Combined elastomer: The patented feature of this invention is that the space between the pressure ring space of the metal structure and the diaphragm groove of the metal accommodates the combined elastomer for forced sealing. The combined elastomer has a radial width of 8t and an axial length of 16t, and a cross-sectional area of ​​8t x 16t. When the holding nut is tightened, a compressive force F is applied to the combined elastomer, and each element of the combined elastomer will squeeze against each other and establish pressure at the sealing interface to achieve a seal. The sealing mechanism of the sealing mechanism completely avoids forced sealing of the outer circumference of the rubber diaphragm gasket when the combined elastomer is forced to complete the seal.

[0081] Static pressure sealing: During tightening, the combined elastomer can generate sufficient deformation, and the sealing interface pressure is formed by the metal valve seat, the support ring, and the diaphragm groove on the annular portion, ensuring high sealing reliability at the interface; when the holding nut is tightened, a tightening force F is applied to the pressure ring, which will couple the force application point in the fixing groove of the pressure ring to the force receiving point of the tightening ring downward, so that the tightening point of the tightening ring presses against the wall thickness of the tightening groove on the circumference of the diaphragm; when the tightening ring When subjected to force and deformation, it will fill the clamping groove and clamp its side wall, while also clamping the wall of the outer diaphragm groove. The metal structure outside the diaphragm groove provides support. The pressure ring will also deform under pressure, causing the sealing liner to bear the clamping force. The sealing liner, its outer metal structure, and the support ring also provide radial support. The axial clearance and the radial clearance are used to accommodate the deformation of the combined elastomer after being clamped, so as to avoid fatigue failure caused by excessive pressure on the clamping ring and the pressure ring.

[0082] Tensile strength and breathing effect: The circumferential portion of the diaphragm is located at the midpoint of the central axis travel. The thickness of the elastic part is t, and its arc-shaped uniform thickness section can reduce the tensile force it can withstand. The sources of tensile force include the pressure of the transported liquid, pipeline pressure fluctuations, and the drastic pressure changes instantaneously generated in the valve chamber due to the breathing effect when the liner valve is opened and closed. When the clamping ring is compressed and deformed to fill the clamping groove and seal the wall material, the first, second, and third corners will contain high rigidity to prevent material migration under tensile force. The sealing length of the first corner of the clamping groove, from the air vent on the air side of the diaphragm, is 15t. The combined elastomer of fluorine material has a radial width of 8t and an axial length of 16t, with a cross-sectional area of ​​8t. The large volume of x16t provides sufficient compression to ensure adequate sealing interface pressure, while the large volume of elastic fluorine material ensures a low compression ratio and reduces the risk of creep. With reduced creep risk, reduced material migration risk, and the sealing length of the compression groove (15t) and the sealing liner isolating the metal structure of the annular portion, it is sufficient to significantly reduce back-diffusion contamination.

[0083] From the above discussion, it can be concluded that the structural features of the sealing mechanism of the present invention, which ensures high reliability, meet the aforementioned four requirements, as explained below:

[0084] Requirement 1: Sealing interface pressure. Maintain appropriate sealing interface pressure. The combined elastomer has a radial width of 8t and an axial length of 16t, with a cross-sectional area of ​​8t x 16t. With the support of the metal structure, it is easy to achieve the working pressure requirement of 10 bar. Moreover, the reserved axial and radial gaps can reduce the risk of overpressure fatigue fracture.

[0085] Requirement 2: Low compressibility. The cross-sectional area of ​​the combined elastomer, supported by a metal structure, is 8t x 16t. It is easy to maintain the sealing interface pressure and has a low compressibility, so it is not easy to cause material fatigue and creep.

[0086] Requirement 3: Tensile strength. When the clamping ring is compressed and deformed to fill the clamping groove and seal the wall material, the first corner, the second corner, and the third corner will contain high rigidity to prevent material migration when subjected to tensile force. The circumferential part is located in the middle of the central shaft stroke. The thickness of the elastic part is t and it is an arc-shaped equal thickness section, which can reduce the tensile force it can withstand.

[0087] Requirement 4: Sealing length. The sealing length from the first corner of the clamping groove to the vent on the air side of the diaphragm is 15t. Combined with the ability to maintain the low compressibility of the combined elastomer, the sealing interface pressure can meet the working pressure requirements and compress the leakage gap size d, thereby increasing the relative gap length L and the length ratio L / d, and significantly reducing the risk of metal ion back diffusion and contamination. The sealing liner is connected to the valve body as a whole and forms an annular stop at the internal thread. The sealing liner isolates the metal part of the valve body, significantly reducing the risk of metal ions being generated and back diffusion and contamination during micro-leakage. Simple Explanation of the Diagram

[0088] [Figure 1] is a cross-sectional view of the lining valve of the present invention.

[0089] [Figure 2] is a cross-sectional view of the valve body of the lining valve of the present invention.

[0090] [Figure 3] is a cross-sectional view of the drive unit of the lining valve of the present invention.

[0091] [Figure 4A] is a cross-sectional view of the sealing mechanism of the lining valve of the present invention.

[0092] [Figure 4B] is a magnified view of a portion of Figure 4A.

[0093] [Figure 5] is a cross-sectional view of the holding nut in the sealing mechanism of the lining valve of the present invention.

[0094] [Figure 6] is a schematic diagram of the deformation of the combined elastomer under forced clamping force in the sealing mechanism of the lining valve of the present invention.

[0095] [Figure 7A] is a schematic diagram of the interface leakage path when the lining valve of the present invention is implemented.

[0096] [Figure 7B] is a schematic diagram of the reverse diffusion path when the lining valve of the present invention is implemented. Implementation

[0097] Please refer to Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7A, and Figure 7B for all explanatory diagrams.

[0098] The conventional liner valve 1 comprises a drive unit 3, a valve body 2, a diaphragm 41, a diaphragm gasket 44, and a sealing mechanism 4.

[0099] The drive unit 3 includes a central shaft 31, a threaded part 311, a bearing part 312, a traction part 313, a pressure handle 32, a traction groove 321, a threaded hole 322, a pressing surface 323, a rotating wheel 34, a drive bushing 35, an internal thread 351, a valve cover 36, an upper flange 361, a central hole 362, a shaft seat 363, a shaft cover 37, and a positioning cover 38.

[0100] The valve body 2 includes an inlet flow channel 21, a valve chamber 22, a valve seat 221, an annular flow channel 23, an outlet flow channel 24, a lower flange 254, a liner 26, and a metal body 27.

[0101] The lower flange 254 includes a sealing seat 251 and a diaphragm groove 252; the upper flange 361 and the lower flange 254 constitute a sealing flange, and the sealing interface of the sealing flange of the conventional diaphragm valve 1 is an annular plane.

[0102] The liner 26 is made of fluorinated materials such as PFA and PTFE. The liner 26 covers the entire valve body 2, including the inlet flow channel 21, the valve chamber 22, the valve seat 221, the annular flow channel 23, the outlet flow channel 24, and the lower flange 254, and includes the sealing seat 251 and the diaphragm groove 252 of the lower flange 254, forming the flange sealing interface.

[0103] The diaphragm 41 includes a blocking portion 411, an elastic portion 413, and a circumferential portion 414; the blocking portion 411 includes a threaded hole 412 through which a diaphragm bolt 45 can be connected to the central shaft 31, and the circumferential portion 414 is installed in the diaphragm groove 252.

[0104] The diaphragm pad 44 includes an outer circumference 443. When the outer circumference 443 and the circumference portion 414 are forced together, they can be used to support the diaphragm 41 to withstand high working pressure and prevent the diaphragm 41 from deforming unevenly under pressure. The outer diameter of the outer circumference 443 is equal to the outer diameter of the diaphragm 41.

[0105] The upper flange 361 of the valve cover 36 of the drive unit 3 is mounted on the lower flange 254 of the valve body 2.

[0106] The sealing mechanism 4 is located on the lower flange 254 and includes the sealing seat 251, the diaphragm groove 252, the diaphragm 41, the diaphragm gasket 44, etc., and is locked by a locking bolt 6 to simultaneously compress the circumferential portion 414 and the outer circumference 443; the circumferential portion 414 and the outer circumference 443 form a combined elastomer 7 to achieve a highly reliable seal.

[0107] The patented features of the liner valve of this invention are improved from the above-mentioned conventional liner valves and include:

[0108] The valve body 2 includes the inlet flow channel 21, the valve chamber 22, the valve seat 221, the annular flow channel 23, the outlet flow channel 24, an annular portion 25, the liner 26, and the metal body 27.

[0109] The annular portion 25 is open cup-shaped and includes the sealing seat 251, the diaphragm groove 252, the cup-shaped space 253, the lower flange 254, and also includes an internal thread 255 and a sealing liner 261.

[0110] The sealing seat 251 is a metal structure, and the sealing seat 251 located on the inner diameter of the annular portion 25 is provided with an inwardly concave annular diaphragm groove 252.

[0111] The sealing liner 261 is connected to the liner 26 of the valve body 2 as a whole, extending from the surface of the diaphragm groove 252 at the bottom of the annular portion 25 and ending in an annular shape at the internal thread 255.

[0112] The sealing mechanism 4 is located in the annular portion 25 and includes the sealing seat 251, the diaphragm groove 252, the sealing liner 261, the diaphragm 41, the diaphragm gasket 44, the diaphragm bolt 45, a clamping ring 42, a pressure ring 43, a holding nut 5, a deformation space 46, etc.; the deformation space 46 includes a radial gap 461 and an axial gap 462.

[0113] The radial section of the clamping ring 42 is rectangular, with two pointed ends containing a force-bearing point 422 and a clamping point 421, respectively.

[0114] The diaphragm 41 includes the blocking portion 411, the elastic portion 413, the circumferential portion 414, etc.; the circumferential portion 414 includes a clamping groove 415, the clamping groove 415 is a square groove including a first corner 416, a second corner 417, a third corner 418, etc., and these corners have high rigidity to prevent material migration when subjected to tensile force; the clamping groove 415 can be installed in the diaphragm groove 252 on the sealing seat 251; the clamping ring 42 is installed in the clamping groove 415 and extends more than half of its length.

[0115] The pressure ring 43 has a rectangular cross-section, and its lower half includes a fixing groove 431 with a rectangular opening. The fixing groove 431 of the pressure ring 43 can accommodate and fix the protruding part of the clamping ring 42. The fixing groove 431 contains a force application point 432, and there is an axial gap 462 between the pressure ring 43 and the diaphragm groove 252.

[0116] The sealing liner 261, the clamping groove 415, the clamping ring 42, the pressure ring 43, etc., form a combined elastic body 7 under clamping.

[0117] The grip nut 5 has a cross-section of a centrally protruding, open cup-shaped metal structure, including an external thread 51, a shaft hole 52, an annular groove 53, a support ring 54, an opening 55, a plurality of support ribs 551, and an inner chamber 56.

[0118] The holding nut 5 can be tightly locked to the internal thread 255 of the annular portion 25 through the external thread 51, providing a downward clamping force F to clamp and deform the pressure ring 43.

[0119] The annular groove 53 has an outer diameter opening, and a pressure ring space is formed between the inner diameter of the annular portion 25 and the support ring 54 to accommodate the pressure ring 43. The radial gap 461 is left between the pressure ring space and the pressure ring 43.

[0120] The diaphragm pad 44 has a circular rubber cross-section but is thicker than the diaphragm 41. The diaphragm pad 44 includes a coupling portion 441, a support portion 442, an outer circumference 443, and a groove 444. The groove 444 is located on the outer circumference 443 and is pressed by the end of the support ring 54 to provide tension support for the diaphragm pad 44 on the diaphragm 41. The outer diameter of the outer circumference 443 is equal to the inner diameter of the pressure ring 43.

[0121] The shaft hole 52 is located on the central protrusion of the holding nut 5 and is used to accommodate the bearing and the central shaft 31. The central shaft 31 is connected to the threaded hole 412 on the blocking part 411 of the diaphragm 41 through the diaphragm bolt 45, and the driving part 3 causes the diaphragm 41 to reciprocate to open or close the inlet flow channel 21 in the valve body 2. The outer diameter of the opening 55 is fitted with the external thread 51, and the plurality of support ribs 551 connect the inner diameter of the opening 55 and the outer diameter of the shaft hole 52 to increase the structural strength of the holding nut 5.

[0122] The internal chamber 56 is located at the front end of the holding nut 5 and is used to accommodate the structure of the connection between the diaphragm gasket 44, the blocking portion 411 of the diaphragm 41, and the central shaft 31.

[0123] Combined elastomer 7: The patented feature of this invention is that the combined elastomer 7 is accommodated in the axial space between the pressure ring space of the metal structure and the diaphragm groove 252 of the metal for forced sealing. The combined elastomer 7 has a radial width of 8t and an axial length of 16t, and its cross-sectional area is 8t x 16t. When the holding nut 5 is tightened, a compressive force F is applied to the combined elastomer 7, and each element of the combined elastomer 7 will squeeze against each other and establish a sealing interface pressure to achieve a seal. The sealing mechanism of the sealing mechanism 4, by forcing the combined elastomer 7 to complete the seal, completely avoids the forced sealing method on the outer circumference 443 of the rubber diaphragm gasket 44.

[0124] Static pressure sealing: During tightening, the combined elastomer 7 can generate sufficient deformation, and the sealing interface pressure is formed by the metal valve seat 221, the support ring 54, and the diaphragm groove 252 on the annular portion 25, ensuring high sealing reliability at the interface; when the holding nut 5 is tightened, a tightening force F is applied to the pressure ring 43, which will cause the force application point 432 in the fixing groove 431 to couple with the force receiving point 422 of the tightening ring 42 to press downward, so that the tightening point 421 of the tightening ring 42 presses against the wall thickness of the tightening groove 415 on the circumferential portion 414 of the diaphragm 41; when the tightening... When the ring 42 is deformed under force, it will fill the clamping groove 415 and clamp its side wall, while also clamping the wall of the outer diaphragm groove 252. The metal structure outside the diaphragm groove 252 provides support. The pressure ring 43 will also be deformed under pressure, causing the sealing liner 261 to bear the clamping force. The sealing liner 261, its outer metal structure, and the support ring 54 also provide radial support. The axial clearance 462 and the radial clearance 461 are used to accommodate the deformation of the combined elastomer 7 after being clamped, so as to avoid the clamping ring 42 and the pressure ring 43 being subjected to excessive pressure and causing fatigue failure.

[0125] Tensile sealing (tensile strength and breathing effect): The circumferential portion 414 of the diaphragm 41 is located at the middle position of the stroke of the central axis 31. The thickness of the elastic portion 413 is t and it has an arc-shaped equal thickness section, which can reduce the tensile force it can withstand. The sources of tensile force include the pressure of the conveyed liquid, pipeline pressure fluctuations, and the breathing effect of the liner valve 1 when it is opened and closed, resulting in a sudden and violent pressure change in the valve chamber 22. When the clamping ring 42 is compressed and deformed to fill the clamping groove 415 and presses the wall material to seal, the first angle 416, the second angle 417, and the third angle 418 will contain high rigidity to prevent material migration when subjected to tensile force. The sealing length of the first angle 416 of the clamping groove 415, from the breather hole 28 on the air side of the diaphragm 41 to the sealing length is 15t. The combined elastomer of fluorine material has a radial width of 8t and an axial length of 16t, and its cross-sectional area reaches 8t. The large volume of x16t provides sufficient compression to ensure adequate sealing interface pressure, while the large volume of elastic fluorine material ensures a low compression ratio, reducing the risk of creep. With reduced creep risk, reduced material migration risk, and the sealing length of 15t of the compression groove 415 and the sealing liner 261 effectively isolating the metal structure of the annular portion 25, back diffusion contamination is significantly reduced. As shown in Figures 7A and 7B, both the leakage path and the back diffusion path are completely sealed and blocked. After the fitting is connected to the liner valve 1, the chemical solution will not come into contact with the metal part of the liner valve 1, and even a small leak will not come into contact with the metal part of the liner valve 1, thus preventing the generation of metal ion contaminants.

[0126] Test Results: A high-temperature leak test was performed using air. The data from the air leak tester are as follows: Test stress 6kg / cm2 Permissible leakage Benchmark (Q) ≤ml / min Permissible pressure difference Standard value (ΔP) ≤Pa Leakage coefficient (Ve) Valve body + instrument + tube length, ml Detecting pressure difference (Ten averages) (ΔP)Pa Leakage Calculation (Q) ml / min determination Sample 1 0.75ml / min 40Pa 63ml 20.3Pa 0.38 OK Sample 2 20.6Pa 0.38 OK illustrate: Leakage calculation formula: T: Detection time, 10 seconds.

[0127] 1: Liner Valve

[0128] 2: Valve body

[0129] 21: Inlet Flow Channel

[0130] 22: Valve chamber

[0131] 221: Valve seat

[0132] 23: Annular flow channel

[0133] 24: Outlet Flow Channel

[0134] 25: Circular part

[0135] 251: Sealing seat

[0136] 252: Diaphragm groove

[0137] 253: Cup-shaped space

[0138] 254: Lower flange

[0139] 255: Internal thread

[0140] 26: Lining

[0141] 261: Sealing Liner

[0142] 27:Metal body

[0143] 28: Breathing hole

[0144] 3: Drive Unit

[0145] 31: Central axis

[0146] 311: Threaded section

[0147] 312: Bearing section

[0148] 313: Traction Unit

[0149] 32: Press handle

[0150] 321: Traction Trough

[0151] 322: Threaded hole

[0152] 323: Pressing surface

[0153] 34 rotating wheels

[0154] 35: Drive bushing

[0155] 351: Internal thread

[0156] 36: Valve cover

[0157] 361: Upper flange

[0158] 362: Center Hole

[0159] 363: Shaft seat

[0160] 37: Shaft cover

[0161] 38: Positioning Cover

[0162] 4: Sealing mechanism

[0163] 41: Membrane

[0164] 411: Blocking section

[0165] 412: Threaded hole

[0166] 413: Elastic part

[0167] 414: Circumference

[0168] 415: Pressing Groove

[0169] 416: First Turn

[0170] 417: Second Turn

[0171] 418: Third Turn

[0172] 42: Tightening Ring

[0173] 421: Urgent

[0174] 422: Point of application of force

[0175] 43: Pressure Ring

[0176] 431: Fixing slot

[0177] 432: Point of application of force

[0178] 44: Diaphragm gasket

[0179] 441: Coupling section

[0180] 442: Support section

[0181] 443: Outer circumference

[0182] 444: Groove

[0183] 45: Diaphragm bolts

[0184] 46: Deformation Space

[0185] 461: Radial clearance

[0186] 462: Axial clearance

[0187] 5: Hold the nut

[0188] 51: External thread

[0189] 52: Shaft hole portion

[0190] 53: Annular groove

[0191] 54: Support ring

[0192] 55: Opening

[0193] 551: Support rib

[0194] 56: Content Room

[0195] 6: Tighten the bolts

[0196] 7: Composite elastomers

[0197] F: Pressure force

Claims

1. A liner valve with an improved diaphragm sealing mechanism, comprising a drive unit, a valve body, a diaphragm, a diaphragm gasket, and a sealing mechanism; the drive unit includes a central shaft, a lifting mechanism, and a valve cover; the central shaft is connected to the diaphragm and the lifting mechanism drives the diaphragm to reciprocate, thereby opening or closing a flow channel within the valve body; the lower opening of the valve cover includes an upper flange; the valve body includes a metal body, a liner, an inlet flow channel, a valve chamber, a valve seat, an annular flow channel, an outlet flow channel, and a lower flange; the lower flange includes a sealing seat and a diaphragm groove; The upper flange and the lower flange form a sealing flange, and the sealing interface of the sealing flange is an annular plane; the liner is made of fluoropolymer materials such as PFA and PTFE, and the liner covers the entire valve body, including the inlet flow channel, the valve chamber, the valve seat, the annular flow channel, the outlet flow channel, the lower flange, etc., including the sealing seat and the diaphragm groove of the lower flange, forming the flange sealing interface; the diaphragm includes a blocking part, an elastic part, and a circumferential part; the blocking part includes a threaded hole that can connect to the central shaft, and the circumferential part includes an axial ring; the axial ring is installed in the diaphragm groove; the diaphragm gasket includes an outer circumference, which can be used to support the diaphragm to withstand high working pressure and prevent uneven deformation of the diaphragm under pressure when the outer circumference and the circumferential part are forced together; its outer diameter is equal to the outer diameter of the diaphragm; the upper flange of the valve cover of the drive unit is installed on the lower flange of the valve body. The sealing mechanism is located on the lower flange and includes the sealing seat, the diaphragm groove, the diaphragm, and the diaphragm gasket. The upper flange and the lower flange are locked together by a locking bolt to simultaneously compress the axial ring of the circumference of the diaphragm and the outer circumference of the diaphragm gasket. The axial ring and the outer circumference form a combined elastic body to achieve a seal on the circumference. The valve body is characterized by improvements based on the aforementioned features, comprising: a metal body, a liner, an inlet channel, a valve chamber, a valve seat, an annular channel, an outlet channel, and an annular portion; the annular portion is open-cup shaped and includes a sealing seat, a diaphragm groove, a cup-shaped space, a lower flange, and also includes an internal thread and a sealing liner; the sealing seat is a metal structure located on the inner diameter side of the bottom of the annular portion, and the sealing seat has an inwardly recessed annular diaphragm groove; the sealing liner is connected to the liner of the valve body as a whole, and the sealing liner extends from the surface of the diaphragm groove at the bottom of the annular portion and ends annularly at the internal thread; the sealing mechanism is located in the annular portion and includes the sealing seat, the diaphragm groove, the sealing liner, the diaphragm, the diaphragm gasket, a clamping ring, a pressure ring, and a holding nut; the clamping ring has a rectangular radial cross-section, with two pointed ends each including a force-bearing point and a clamping point; The diaphragm includes the blocking portion, the elastic portion, and the circumferential portion; the circumferential portion includes a clamping groove, which is a square groove including a first corner, a second corner, and a third corner, and these corners include high rigidity to prevent material migration under tensile force; the clamping groove can be installed in the diaphragm groove on the sealing seat; the clamping ring is installed in the clamping groove and extends more than half of its length; the pressure ring has a rectangular cross-section, and its lower half includes a fixing groove with a rectangular opening; the fixing groove of the pressure ring can accommodate and fix the protruding portion of the clamping ring, and the fixing groove includes a force application point; the sealing liner, the clamping groove, the clamping ring, and the pressure ring, etc., form a clamped combined elastic body; The grip nut has a cross-section of a centrally protruding, open cup-shaped metal structure, including an external thread, a shaft hole, an annular groove, a support ring, an opening, multiple support ribs, and an inner chamber. The grip nut can be tightly locked to the inner thread of the annular portion through the external thread, providing a downward clamping force (F) to apply clamping force to the combined elastomer to induce deformation and achieve a highly reliable seal.

2. The liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, The diaphragm pad has an outer circumference containing a groove that is pressed by the end of the support ring to provide tension support for the diaphragm pad on the diaphragm. The outer diameter of the outer circumference is equal to the inner diameter of the pressure ring.

3. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, The annular groove has an inner opening with an outer diameter, and a pressure ring space is formed between the inner diameter of the annular portion and the support ring to accommodate the pressure ring. When the pressure ring is accommodated in the pressure ring space, a radial gap is left.

4. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, An axial gap is left between the pressure ring and the diaphragm groove.

5. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, The sealing mechanism of the sealing device completely avoids the tight sealing of the outer circumference of the rubber diaphragm gasket when the combined elastomer is tightened to complete the seal.

6. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, To meet requirement 1 (sealing interface pressure) and maintain appropriate sealing interface pressure, the combined elastomer has a radial width of 8t and an axial length of 16t, with a cross-sectional area of ​​8t x 16t. With the support of a metal structure, it is easy to achieve the working pressure requirement of 10 bar. In addition, there are reserved axial and radial clearances to reduce the risk of overpressure fatigue fracture.

7. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, To meet requirement two (low compressibility), the cross-sectional area of ​​the combined elastomer supported by the metal structure is 8t x 16t, which makes it easy to maintain the sealing interface pressure and has a low compressibility, thus reducing the likelihood of material fatigue and creep.

8. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, To meet requirement three (tensile strength), when the clamping ring is compressed and deformed to fill the clamping groove and seal the wall material, the first corner, the second corner, and the third corner will contain high rigidity to prevent material migration when subjected to tensile force; the circumferential part is located in the middle of the central shaft stroke, and the thickness of the elastic part is t and it is an arc-shaped equal thickness section, which can reduce the tensile force it can withstand.

9. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, To meet requirement four (sealing length), the sealing length from the first corner of the clamping groove to the vent on the air side of the diaphragm is 15t. In addition, the low compressibility of the combined elastomer can be maintained, so the sealing interface pressure can meet the working pressure requirements and compress the leakage gap size d, thereby increasing the relative gap length L and the length ratio L / d, and significantly reducing the risk of reverse diffusion of metal ions.

10. A liner valve with an improved diaphragm sealing mechanism as described in claim 1, wherein, To reduce the risk of reverse diffusion of metal ions, the sealing liner is connected to the liner of the valve body as a whole. The sealing liner extends from the diaphragm groove surface at the bottom of the annular portion and ends annularly at the internal thread. In this way, the sealing liner isolates the metal part of the valve body, greatly reducing the risk of metal ions being generated and diffusing into the valve body during micro-leakage.

Images