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FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See section 10 and rule 13]
TITLE OF THE INVENTION
STEM SEALING SYSTEM AND ARRANGEMENT THEREOF
2. APPLICANT
Name
Nationality
Address
IDEX INDIA PVT LTD
INDIA
REVENUE SURVEY NO. 256, MANJUSAR – G.I.D.C., MANJUSAR, SAVLI ROAD, VADODARA - 391775, GUJARAT, INDIA
The following specification particularly describes and ascertains the nature of the invention and the manner in which it is to be performed.
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STEM SEALING SYSTEM AND ARRANGEMENT THEREOF
TECHNICAL FIELD
[0001] The present disclosure relates generally to valve systems used in controlling flow of fluids and more specifically, to stem sealing systems to ensure stabilized sealing force in the valve systems.
BACKGROUND
[0002] Generally, valves are utilized to regulate the flow of fluids such as liquids, gases and slurries over a wide range of temperatures and pressures. These valves are used in a wide variety of applications, particularly industrial applications such as refining, chemicals, petrochemicals, pharmaceuticals, water treatment, mining, power generation and so forth. Typically, at higher pressures and temperatures, valves are susceptible to leakages. Valves having a rotating, reciprocating, sliding, or otherwise moving components, such as a valve stem, which when subjected to pressure, will lead to a leakage of the fluid passing through the valve. Perhaps, there is a possibility of some minute leakage even in the stationary position of the moving components. This may lead to a leakage of chemicals, oils, or hazardous fluids into the environment. Therefore, it is desirable to prevent or to reduce the possibility of leakage of fluids from the valves. Furthermore, with the increasing emphasis on environmental quality, leakage of gases, oils, or other toxic or hazardous fluids into the environment is dangerous. Additionally, leakage of fluids from the valves may affect an efficiency of the process, operations, and the like.
[0003] Conventionally, to prevent such leakage, sealing systems are employed to withstand a range of temperatures and pressures. One such conventional sealing system utilizes a stem seal secured into position around the valve stem using fasteners such as bolts. However, such conventional sealing systems have several limitations.
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One of the major problems is insufficient and inadequate capacity of sealing the leakages under high pressure or high temperature conditions. For example, valves may be exposed to uneven fluctuations in the pressure and temperature, e.g. thermal cycling, causing its seals to contract and expand rapidly, which may degrade the seal over time and impact the reliability of the valve. In addition, the reliability of a valve seal may be impacted by vibrations and rotational forces. Another problem is premature wear and tear of the valve system and the sealing system resulting in less durability and reliability of such sealing systems. For example, when in operation a stem seal is subjected to rotational forces as a valve is in motion, leading to degradation of the integrity of the seal. Additionally, valves are often exposed to high pressure fluctuations causing vibrations that degrade the seal. However, conventional sealing systems are not designed to withstand such rapid fluctuations of pressure and temperature leading to leakage of fluids from the valves. Furthermore, the leakage leads to need of frequent maintenance and repair of the valves and the sealing systems which, in turn, leads to increase in operational costs.
[0004] Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with the conventional sealing systems of plug valves.
SUMMARY
[0005] In one aspect of the present disclosure, there is provided a stem sealing system (200) utilized with a valve (100) that has a valve body (211), the valve having a plug (210) pressed into the valve body (211). The stem sealing system includes a diaphragm (208) supported on a top surface of the plug (210), a diaphragm plate (207) mounted on an upper surface of the diaphragm (208), a pressure plate (206) mounted on the diaphragm plate (207), wherein the diaphragm plate (207) supports the diaphragm (208) against internal pressure and deformation against force developed by the pressure plate (206), a cup spring (204) arranged on a top surface of the
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pressure plate (206) for providing a compressive force on the pressure plate (206) against the diaphragm (208), a wedge ring (209) supported on a top surface of the plug (210), and arranged between the plug (210) and the diaphragm (208), an O-ring (205) sandwiched between the diaphragm (208) and the wedge ring (209), and at least three hex bolts (201) mounted on a bonnet of the valve body. The at least three hex bolts are adapted to be provided with torque to press the cup spring (204) downwards to provide compressive force onto the pressure plate (206), the pressure plate (206) then pressing the diaphragm (208) to develop a first force in a horizontal direction towards a stem portion of the valve body (211) and a second force in a vertical direction towards a top surface of the plug (210), and wherein the first force creates a force on the wedge ring and subsequently to the O-ring for creating a re-silence force, a to cause the cup spring, the diaphragm, along with the wedge ring and the O-ring, to form a seal inside the valve body.
[0006] In another aspect of the present disclosure, there is provided a valve body (211), a plug (210) pressed into the valve body (211), wherein the plug (210) is equipped with a stem sealing system (200). The stem sealing system (200) includes a diaphragm (208) supported on a top surface of the plug (210), a diaphragm plate (207) mounted on an upper surface of the diaphragm (208), a pressure plate (206) mounted on the diaphragm plate (207), wherein the diaphragm plate (207) supports the diaphragm (208) against internal pressure and deformation against force developed by the pressure plate (206), a cup spring (204) arranged on a top surface of the pressure plate (206) for providing a compressive force on the pressure plate (206) against the diaphragm (208), a wedge ring (209) supported on a top surface of the plug (210), and arranged between the plug (210) and the diaphragm (208), an O-ring (205) sandwiched between the diaphragm (208) and the wedge ring (209), and at least three hex bolts (201) mounted on a bonnet of the valve body, wherein the at least three hex bolts are adapted to be provided with torque to press the cup spring (204) downwards to provide compressive force onto the pressure plate (206), the pressure
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plate (206) then pressing the diaphragm (208) to develop a first force in a horizontal direction towards a stem portion of the valve body (211) and a second force in a vertical direction towards a top surface of the plug (210), and wherein the first force creates a force on the wedge ring and subsequently to the O-ring for creating a re-silence force, a to cause the cup spring, the diaphragm, along with the wedge ring and the O-ring, to form a seal inside the valve body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
[0008] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
[0009] FIG. 1A is an illustration of a perspective view of a plug valve, in accordance with an embodiment of the present disclosure;
[00010] FIG. 1B is an illustration of a side planar view of the plug valve of FIG. 1A, in accordance with an embodiment of the present disclosure;
[00011] FIG. 2A is an illustration of a cross-sectional view of the plug valve showing a stem sealing system, in accordance with an embodiment of the present disclosure; and
[00012] FIG.2B is an enlarged view of the stem sealing system, in accordance with an embodiment of the present disclosure.
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DETAILED DESCRIPTION OF THE DRAWINGS
[00013] Referring to FIGS. 1A and 1B, there is shown a schematic illustration of a plug valve 100, in accordance with an embodiment of the present disclosure.
[00014] The plug valve 100 is a mechanical device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. The plug valve 100 is a valve with a cylindrical or conically tapered plug 102 which can be rotated inside a valve body 104 to control flow through the valve 100. Such plug 102 may have one or more hollow passageways going sideways through the plug 102, so that fluid can flow through the plug 102 when the valve 100 is open.
[00015] As shown, the plug valve 100 includes the valve body 104 extending through a stem opening there within. The plug valve 100 includes the plug 102 pressed into the valve body 104. The plug valve 100 further includes a bonnet 106 arranged on the valve body 104. The plug valve 100 furthermore includes at least three bolts or a grub screw 108 arranged on the bonnet 106.
[00016] It will be appreciated that the term “valve body” used herein relates to a structural frame produced from solid hardened material such as metals, metal alloys, and the like. The term “bonnet” used herein relates to a structural covering, housing and the like produced from solid hardened material such as metals, metal alloys, and the like. Furthermore, the bonnet 106 provides a protective covering to components enclosed therein. The bonnet 106 ensures zero leakage of process fluid from top of the plug valve 100.
[00017] Further, the term “plug” used herein relates to a mechanical component that is pressed into the valve body 104, to provide to block or substantially restrict the flow of fluids through the plug valve 100. In an example, a shape of the plug 102 may substantially mimic a shape of a piston or a plunger. In another example, the plug 102
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may be utilized to seal leakage of fluids from the valve 100. Specifically, pressure force from the fluids is exerted at a surface of the plug 102. The plug 102 may be manufactured using solid hardened material such as alloys, metal alloys, and the like.
[00018] FIG. 2A illustrate a cross-sectional view of the plug valve 100, along an axis A-A, and FIG.2B illustrates an enlarged view of a stem sealing system 200 of the plug valve 100, in accordance with an embodiment of the present disclosure. The plug valve 100 is formed of at least three hex bolts 201, a bonnet 202 (similar to the bonnet 106), a washer 203, a cup spring 204, an O-ring 205, a pressure plate 206, a diaphragm plate 207, a diaphragm 208, a wedge ring 209, a plug 210 (similar to the plug 102), a valve body 211 (similar to the valve body 104), a sleeve 212, a hex nut 213, a hex bolt 214, a tag plate 215, and a V-ring 216. [00019] The plug 210 is pressed in the valve body 211, and employs a stem sealing system 200 that ensures zero leakage of process fluid in corresponding process plant, due to dynamic nature of process parameters, and a wide range of temperature difference in surrounding environment of the valve 100. [00020] The stem sealing system 200 is formed of the washer 203, the cup spring 204, the O-ring 205, the pressure plate 206, the diaphragm plate 207, the diaphragm 208, and the wedge ring 209.
[00021] The diaphragm 208 is a mechanical component that rests on the cylindrical top portion of the plug 210. The pressure plate 206 is a disc-like structure arranged on the diaphragm 208. In one example, the pressure plate 206 is a disc having elevated holes at the center, wherein two discs are reversely placed over each other. When the pressure force is applied at suspended ends of the two discs, the elastic nature of the two discs widens the radius at the suspended ends to accommodate the pressure force therein. In another example, the pressure plate 206 is a disc having cylindrical coils with smaller radius at the center and gradually
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increasing radii at extreme ends. When the pressure force is applied at such disc, the suspended ends enlarge enough to accommodate the applied pressure force therein.
[00022] The diaphragm plate 207 rests on an upper surface of the diaphragm 208 to support the diaphragm 208 against internal pressure and deformation against force developed by the pressure plate 206. The cup spring 204 is arranged on a top surface of the pressure plate 206, and produce a compressive force on the pressure plate 206. The washer 203 is a circular disc mounted on the cup spring 204 followed by the hex bolts 201 mounted on the bonnet 202 to provide support thereto. The washer 203 may take the impact when the pressure is exerted over it upon tightening of the hex bolts 201.
[00023] The wedge ring 209 relates to a half cone shaped mechanical component provided between the plug 210 and the diaphragm 208, and supported on a top surface of the plug 210, to incorporate the pressure force exerted from the plug 210 via the diaphragm 208. The O-ring 205 is a circular ring sandwiched between the diaphragm 208 and the wedge ring 209 to provide a resilient support thereto.
[00024] In an example, the diaphragm 208 and the wedge ring 209 may be manufactured using solid hardened material such as Polytetrafluoroethylene (PTFE). The O-ring 205 may be manufactured from viton or rubber. The pressure plate 206 may be manufactured using solid hardened material such as alloys, metal alloys, and the like. The cup spring 204 may be manufactured using hardened elastic material such as alloys, metal alloys, spring, steel, and the like.
[00025] In operation, tightening of the hex bolts 201 from top with calculated torque provides a downward motion to the washer 203, which then presses the cup spring 204 to produce a compressive force on the pressure plate 206. The pressure plate 206 then presses the diaphragm 208 by developing two components of force, one in horizontal direction towards stem, and other in vertically downward direction towards a top surface of the plug 210. The force in horizontal direction creates a force
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on the wedge ring 209 which then creates a force on the O-ring 205, which then creates a re-silence force on the stem, and create a stabilized force for sealing fluids.
[00026] In an embodiment of the present disclosure, the diaphragm 208 is compressed by the force transmitted from the hex bolt 201 and the cup spring 204 in downward direction. As a result of which, the wedge ring 209 compresses the O-ring 205 from bottom, resulting in deformation of the O-ring 205 up to its elastic limit and creating a resilience force. The O-ring 205 transfers the pressure force to the wedge ring 209, thereby extending the circumference of the wedge ring 209.
[00027] The resilience force and the energy stored in the cup spring 204 due to constant compression makes the plug valve 100 stable to work under a wide range of temperature variation and to take care of dynamic characteristics of process fluid.
[00028] In another embodiment of the present disclosure, the cup spring 204 provides a resilience support, when there are fluctuations in the pressure force exerted at the lower surface of the plug 210. The use of cup spring 204 provides uniform force on stem seal and plug thereof, by increasing life of stem sealing components and also avoiding uneven force on to the plug valve 100.
[00029] The diaphragm plate 207 resting on the diaphragm 208 is utilized in order to support the diaphragm 208 against deformation due to the compressive force from the pressure plate 206. The diaphragm plate 207 includes an elevated loop, that extends or deforms elastically, when the pressure force is applied to the plug 210.
[00030] The stem sealing system 200 ensures zero leakage in the process plant, as there is wide range of temperature difference in surrounding environment of the valve 100 and process parameters are dynamic in nature. The stem sealing system 200 creates dynamic stability in sealing areas, as it utilizes techniques to compensate effect of wide range of temperature change in process plant. The stem sealing system 200 is designed in such a way to reduce opening and closing torque of valve. The cup spring
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204 and the O-ring 205 are designed to take dynamic loads to ensure stabilized sealing force.
[00031] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
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We claim:
1. A stem sealing system (200) utilized with a valve (100) that has a valve body (211), the valve having a plug (210) pressed into the valve body (211), the stem sealing system (200) comprising:
a diaphragm (208) supported on a top surface of the plug (210);
a diaphragm plate (207) mounted on an upper surface of the diaphragm (208);
a pressure plate (206) mounted on the diaphragm plate (207), wherein the diaphragm plate (207) supports the diaphragm (208) against internal pressure and deformation against force developed by the pressure plate (206);
a cup spring (204) arranged on a top surface of the pressure plate (206) for providing a compressive force on the pressure plate (206) against the diaphragm (208);
a wedge ring (209) supported on a top surface of the plug (210), and arranged between the plug (210) and the diaphragm (208);
an O-ring (205) sandwiched between the diaphragm (208) and the wedge ring (209); and
at least three hex bolts (201) mounted on a bonnet of the valve body, wherein the at least three hex bolts are adapted to be provided with torque to press the cup spring (204) downwards to provide compressive force onto the pressure plate (206), the pressure plate (206) then pressing the diaphragm (208) to develop a first force in a horizontal direction towards a stem portion of the valve body (211) and a second force in a vertical direction towards a top surface of the plug (210), and wherein the first force creates a force on the wedge ring and subsequently to the O-ring for creating a re-silence force, a to cause the cup spring, the diaphragm, along with the wedge ring and the O-ring, to form a seal inside the valve body.
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2. The stem sealing system as claimed in claim 1, wherein the valve (100) comprises a bonnet (202) arranged on the valve body (211).
3. The stem sealing system as claimed in claim 1, wherein the valve (100) comprises a washer (203) mounted on the cup spring (204) to take impact while pressing thereof due to the torque provided to the nut from top of the bonnet (202).
4. The stem sealing system as claimed in claim 1, wherein the stem sealing system (200) ensures zero leakage of process fluid in corresponding process plant, due to dynamic nature of process parameters, and a wide range of temperature difference in surrounding environment of the valve (100).
5. The stem sealing system as claimed in claim 1, wherein each of the diaphragm (208) and the wedge ring (209) are manufactured using Polytetrafluoroethylene (PTF), the O-ring (205) is manufactured from at least one of: viton and rubber, the pressure plate (206) is manufactured using a solid hardened material, and the cup spring (204) is manufactured using a hardened elastic material.
6. The stem sealing system as claimed in claim 1, wherein the wedge ring (209) comprises a half cone shaped mechanical component provided between the plug (210) and the diaphragm (208).
7. The stem sealing system as claimed in claim 1, wherein the at least three hex bolts (201) are tightened from top with a calculated torque to provide a downward motion to the washer (203).
8. The stem sealing system as claimed in claim 1, wherein the diaphragm (208) is compressed by a force transmitted from the at least three hex bolts (201) and the cup spring (204) in a downward direction, and the wedge ring (209) compresses the O-ring
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(205) from bottom, resulting in deformation of the O-ring (205) and creating a resilience force.
9. A valve (100) comprising:
a valve body (211);
a plug (210) pressed into the valve body (211), wherein the plug (210) is equipped with a stem sealing system (200) that comprises:
a diaphragm (208) supported on a top surface of the plug (210);
a diaphragm plate (207) mounted on an upper surface of the diaphragm (208);
a pressure plate (206) mounted on the diaphragm plate (207), wherein the diaphragm plate (207) supports the diaphragm (208) against internal pressure and deformation against force developed by the pressure plate (206);
a cup spring (204) arranged on a top surface of the pressure plate (206) for providing a compressive force on the pressure plate (206) against the diaphragm (208);
a wedge ring (209) supported on a top surface of the plug (210), and arranged between the plug (210) and the diaphragm (208);
an O-ring (205) sandwiched between the diaphragm (208) and the wedge ring (209); and
at least three hex bolts (201) mounted on a bonnet of the valve body, wherein the at least three hex bolts are adapted to be provided with torque to press the cup spring (204) downwards to provide compressive force onto the pressure plate (206), the pressure plate (206) then pressing the diaphragm (208) to develop a first force in a horizontal direction towards a stem portion of the valve body (211) and a second force in a vertical direction towards a top surface
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of the plug (210), and wherein the first force creates a force on the wedge ring and subsequently to the O-ring for creating a re-silence force, a to cause the cup spring, the diaphragm, along with the wedge ring and the O-ring, to form a seal inside the valve body.
10. The stem sealing system as claimed in claim 1, wherein the valve (100) comprises a bonnet (202) arranged on the valve body (211), and a washer (203) mounted on the cup spring (204) to take impact while pressing thereof due to the torque provided to the nut from top of the bonnet (202).