Patent Description:
There are numerous types of valves for controlling fluid flow along a fluid pathway, such as, check valves, plug valves, ball valves, stop or globe valves, angle valves, butterfly valves, and gate valves. Many valves, for example, ball valves, globe valves, butterfly valves, and gate valves, include a valve stem that control motion of a valve element. For example, the valve stem may communicate motion from an exterior portion of the valve (e.g., actuator, handle, crank, wheel, etc.) to an interior portion of the valve (e.g., the valve element, such as, a ball, plate, gate, disc, plug, etc.).

In valves that include a valve stem, a seal is generally created between the valve body and the valve stem in order to prevent or minimize fluid from traveling outside of a fluid flow portion of the valve body. In some valves the seal is created with packing material. For example, <CIT>teaches a valve packing system including compacted graphite material. Such graphite material may be formed from spirally coiled graphite tape as disclosed in <CIT>.

The packing material is generally contained in a packing stack. The packing stack may include packing caps (e.g., end rings, guide rings, etc.) on outer ends of the packing stack configured to retain the packing material in position. For example, packing caps are taught by <CIT> and <CIT>. The packing caps may be used to transmit compressive forces on the packing material to maintain a seal against the valve stem.

Document <CIT> discloses a kind of leakage-free valve packing seal structure according to the preamble of claim <NUM> by providing a valve packing with valve filler and a gland ring.

The present invention relates to a valve packing assembly as defined in claim <NUM>, to a valve assembly as defined in claim <NUM> and to a method of defining a seal in a valve assembly as defined in claim <NUM>.

The illustrations presented herein are not meant to be actual views of any particular valve assembly or component thereof, but are merely idealized representations employed to describe illustrative embodiments. Elements common between figures may retain the same numerical designation.

As used herein, relational terms, such as "first," "second," "top," "bottom," etc., are generally used for clarity and convenience in understanding the disclosure and accompanying drawings and do not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.

As used herein, the term "and/or" means and includes any and all combinations of one or more of the associated listed items.

As used herein, the term "fluid" may mean and include fluids of any type and composition. Fluids may take a liquid form, a gaseous form, or combinations thereof, and, in some instances, may include some solid material. In some embodiments, fluids may convert between a liquid form and a gaseous form during a cooling or heating process as described herein.

As used herein, the term "substantially" or "about" in reference to a given parameter means and includes to a degree that one skilled in the art would understand that the given parameter, property, or condition is met with a small degree of variance, such as within acceptable manufacturing tolerances. For example, a parameter that is substantially met may be at least about <NUM>% met, at least about <NUM>% met, at least about <NUM>% met, or even at least about <NUM>% met.

In some embodiments, valves and/or valve assemblies are used in systems involving high temperature fluids and/or high pressure fluids. As the working temperatures and/or pressures of the systems increase, additional problems and considerations are introduced into the design of sealing systems for valves that include interfaces between internal and external components of the valves.

Typical valve sealing systems include end rings or end caps to maintain a valve packing material in position and/or to transmit compressive forces to the packing material to maintain a seal between the stem and the valve body. Typically, the end rings are formed from carbon materials, such as, carbon fiber. In high temperature systems operating temperatures can be in excess of <NUM>,<NUM>°F (<NUM>), such as <NUM>,<NUM>°F (<NUM>), <NUM>,<NUM>°F (<NUM>), or <NUM>,<NUM>°F (<NUM>). Resins present in carbon fiber typically break down at much lower temperatures, such as between about <NUM>°F (<NUM>) and <NUM>°F (<NUM>). Breaking down end rings can have disastrous results such as packing blowout, which can result in severe injuries and/or costly plant shut downs.

Some valves may attempt to remedy the temperature limitations of carbon fiber end rings by placing the sealing system large distances from the operating fluid to allow the body to dissipate heat before the temperature reaches the end rings. This may result in valves that are much larger and/or complex than necessary. Further, space constraints and/or material constraints may make moving the sealing system away from the material difficult or impossible.

<FIG> illustrates a cross-sectional view of an embodiment of a valve assembly <NUM>. The valve assembly <NUM> may include a valve body <NUM>, a stem <NUM>, an actuating element <NUM> (e.g., handle, crank, hand wheel, electronic actuator, pneumatic actuator, hydraulic actuator, other types of at least partially automatic actuators, etc.), and a bonnet assembly <NUM>. The bonnet assembly <NUM> may be configured to create a seal between the valve body <NUM> and the stem <NUM>. For example, the bonnet assembly <NUM> may at least partially isolate fluid flowing within the valve assembly <NUM> from traveling outside of intended fluid flow volume along the stem <NUM>. The stem <NUM> may be configured to communicate motion (e.g., rotation and/or translation) from the actuating element <NUM> located externally (e.g., outside the valve body) to a valve element <NUM> (e.g., gate, disc, wedge, poppet, plug, ball, spindle, plate, etc.) located internally in the valve body <NUM> (e.g., inside the valve body <NUM>). As depicted, the valve body <NUM> may include a valve yoke <NUM> coupled to the bonnet assembly <NUM> on one side (e.g., an actuation side) of the valve assembly <NUM>.

In some embodiments, the valve body <NUM> may include one or more portions of the bonnet assembly <NUM> (e.g., valve bonnet <NUM>). For example, the valve bonnet <NUM> may be a part of the valve body <NUM>. It is noted that, while the embodiments presented herein generally discuss a packing stack that may define a seal between a portion of the valve body <NUM> (e.g., the valve bonnet <NUM>) and the stem <NUM>, in other embodiments, the packing stack may define a seal between other portions of a valve assembly. For example, the packing stack may define a seal between a portion of the valve body <NUM> and the stem <NUM> where the valve body <NUM> may lack a valve bonnet.

<FIG> illustrates a cross-sectional view of an embodiment of a bonnet assembly <NUM>. As depicted, the bonnet assembly <NUM> may include a packing gland <NUM>, a packing stack <NUM> (e.g., a stem packing), and the valve bonnet <NUM>. The valve bonnet <NUM> may define a cavity (e.g., channel, stuffing box, packing chamber, etc.). The packing stack <NUM> may be positioned within (e.g., disposed) the cavity and configured to form a seal between a portion of the valve body <NUM> (e.g., the valve bonnet <NUM>) and the valve stem <NUM>. The packing gland <NUM> may be positioned on an end (e.g., side) of the packing stack <NUM> to secure the packing stack <NUM> in the cavity. The packing gland <NUM> may apply a compressive force on the packing stack <NUM>, such that the seal created by the packing stack <NUM> may increase. For example, at least a portion of the packing stack <NUM> may deform under the compressive force expanding in a direction transverse to the compressive force thereby closing (e.g., reducing) the size of a gap or gaps (e.g., clearance, space, void) that may exist between the packing stack <NUM> and the stem <NUM>. The packing gland <NUM> may be positioned on an opposite end of the packing stack <NUM> from the working fluid, such that the packing gland <NUM> may provide a force in opposition to a force provided by the working fluid due to fluid pressure in the system and maintain the packing stack <NUM> within the cavity in the valve bonnet <NUM>.

In some embodiments, the packing gland <NUM> may include a threaded engagement with the valve bonnet <NUM> such that the force imposed by the packing gland <NUM> on the packing stack <NUM> (e.g., the force applied to the packing stack <NUM> between the packing gland <NUM> and the valve bonnet <NUM>) may be increased or decreased by threading or unthreading the packing gland <NUM> from the valve bonnet <NUM>. In some embodiments, forces to secure the packing stack <NUM> in the cavity and/or to increase the sealing provided by the packing stack <NUM> may be applied to the packing stack <NUM> through a hardware connection (e.g., bolts, screws, studs, nuts, etc.) positioned between the packing gland <NUM> and the bonnet <NUM> and/or the valve body <NUM> (<FIG>). In some embodiments, the packing gland <NUM> may include a secondary member (e.g., clamping arm, packing nut, etc.) configured to apply a force on the packing gland <NUM>, such that the packing gland <NUM> may transfer the force to the packing stack <NUM>.

<FIG> illustrates an enlarged view of a cross-sectional view of an embodiment of the packing stack <NUM>. As depicted, the packing stack <NUM> may include several rings (e.g., annular rings) of packing element and/or material. As disclosed herein, the rings of the packing stack <NUM> may be rings, such as annular rings; however, the rings may include other shapes that include substantially annular, oval, non-annular, polygonal, etc., or any other shapes suitable to define a seal between the valve stem and the valve body (e.g., any shape suitable to surround or encompass the valve stem).

In some embodiments, the packing stack <NUM> may include one or more end rings <NUM> (e.g., end cap, two opposing end rings) and one or more packing rings <NUM> (e.g., two packing rings <NUM>). The end ring <NUM> may be located on an end of the packing stack <NUM>. In some embodiments, the end ring <NUM> may be located on an end of the packing stack <NUM> opposite the working fluid, such that the end ring <NUM> may maintain the packing ring <NUM> between the end ring <NUM> and the working fluid. In some embodiments, the packing stack <NUM> may include two end rings <NUM>. The end rings <NUM> may be located on opposite ends of the packing stack <NUM> such that the packing rings <NUM> are positioned between the end rings <NUM>.

Some embodiments may include between one and ten packing rings <NUM>, such as between one and five, or between two and three. The packing rings <NUM> may be formed from individual annular rings of material. The packing rings <NUM> may be formed from a string (e.g., cord, braided fibers, tape, etc.) formed into a coil corresponding to the number of packing rings <NUM>. In some embodiments, the packing rings <NUM> may be formed from an injectable material injected into the cavity defined by the valve bonnet <NUM>.

In some embodiments, the packing rings <NUM> may be formed from flexible materials capable of operating at elevated temperatures, such as graphite, carbon, PTFE, fiberglass, polyimides, etc. In some embodiments, the packing rings <NUM> may be formed from a single material in a braided configuration or mixtures of the materials in braided configurations. Some embodiments may include a lubricating material (e.g., graphite coating, PTFE coating, etc.) on and/or in the material forming the packing rings <NUM>.

As depicted, the end rings <NUM> may have an annular (e.g., ringed, circular, cylindrical, etc.) shape. The end rings <NUM> may define an annular opening about an axis L<NUM>. The end rings <NUM> may be coaxial with the valve stem <NUM> such that the end rings <NUM> and the valve stem share a common centerline (e.g., longitudinal axis L<NUM>). The end rings <NUM> may define an axial dimension <NUM> (e.g., height, or depth) and a radial dimension <NUM> (e.g., width, or thickness). In some embodiments, the dimensions may be configured to locate and/or retain the end rings in a desired position and/or orientation. For example, the dimensions may be configured to prevent unnecessary contact between the end rings <NUM> and the stem <NUM>, to enable the stem <NUM> to move (e.g., axially and/or radially without binding on the end rings <NUM>), and/or to provide tight clearances to maintain the packing material forming the packing rings <NUM> within the cavity defined by the valve bonnet <NUM>.

In some embodiments, the axial dimension of the end ring <NUM> may be at least one and a half times, twice (e.g., double, two times), three times, or greater the radial dimension of the end ring <NUM>. For example, the ratio between the axial dimension <NUM> and the radial dimension <NUM> may be between about <NUM>:<NUM> and about <NUM>:<NUM>, such as between about <NUM>:<NUM> and about <NUM>:<NUM>, or between about <NUM>:<NUM> and about <NUM>:<NUM>. In some embodiments, the end rings <NUM> may be formed from a rigid material to transmit the compressive forces from the packing gland <NUM> to the packing rings <NUM> without substantial deformation of the end rings <NUM>.

In some embodiments, the end rings <NUM> may be formed from a metal or metal alloy material configured to operate in high pressure and/or high temperature environments (e.g., in continuous service in a caustic environment). For example, the end rings <NUM> may be formed from a metal or metal alloy material suitable for reliable operation without substantial failure at temperatures above about <NUM>,<NUM>°F (<NUM>), such as above about <NUM>,<NUM>°F (<NUM>), above about <NUM>,<NUM>°F (<NUM>), above about <NUM>,<NUM>°F (<NUM>), or above <NUM>,<NUM>°F (<NUM>). In such embodiments, the end rings <NUM> may be formed from metals and/or metal alloys including materials, such as, for example, silicon, manganese, chromium, nickel, columbium (niobium), molybdenum, tantalum, cobalt, and iron. For example, the end rings <NUM> may comprise metals or alloys including <NUM> (e.g., NITRONIC® <NUM>®, UNS S21800), <NUM> (e.g., INCONEL® <NUM>, UNS N06600), <NUM> (e.g., INCONEL® <NUM>, UNS N06601), <NUM> (e.g., INCONEL® <NUM>, UNS N06625), <NUM> (e.g., INCONEL® <NUM>, UNS N07718), <NUM> (e.g., INCONEL® <NUM>, UNS No. N07740), <NUM> (e.g., INCOLOY® <NUM>, UNS N08810), 800HT (e.g., INCOLOY® 800HT, UNS N08811), or <NUM> (e.g., UNS G41400).

In some embodiments, the metal material of the end rings <NUM> may be the same metal material as the valve bonnet <NUM> and/or the valve body <NUM> (<FIG>). In some embodiments, the end rings <NUM> may each be formed from the same material. In some embodiments, the end rings <NUM> may be formed from different materials. For example, the end ring <NUM> proximate the working fluid may be formed from a different material than the end ring <NUM> on the opposite end of the packing stack <NUM> (e.g., where the working fluid may comprise a caustic, a high temperature, a high pressure, and/or another potentially damaging fluid).

In some embodiments, the end rings <NUM> may include two or more rings (e.g., interlocking rings, complementary rings, etc.). The interlocking rings may include an outer ring <NUM> and an inner ring <NUM>. As depicted, the inner ring <NUM> may define a shelf <NUM> (e.g., an annular notch, an annular recess) configured to retain the outer ring <NUM> in a volume defined between the inner ring <NUM>, the valve bonnet <NUM>, and the packing rings <NUM>. In some embodiments, the outer ring <NUM> may be configured to fit substantially entirely within the shelf <NUM> when assembled. The outer ring <NUM> may fit in the shelf <NUM> such that a bottom surface of the outer ring <NUM> and a bottom surface of the inner ring <NUM> may be substantially coplanar (e.g., aligned). For example, the bottom surfaces of the inner ring <NUM> and the outer ring <NUM> may be adjacent the packing rings <NUM>. While, as depicted, the inner ring <NUM> and the outer ring <NUM> are shown with substantially parallel surfaces (e.g., extending substantially parallel or perpendicular) to the valve stem <NUM>) that are positioned adjacent to each other (e.g., bordering, opposing surface defining a common boundary) in the axial and/or radial directions, in other embodiments, such adjacent interacting surfaces may comprise other configurations. For example, such surfaces may be aligned at oblique angles (e.g., tapered surfaces of tapered rings, angled surfaces, etc.), have irregular complementary surfaces (e.g., with protrusions and recesses), have stepped surface features, and/or other complementary features.

In some embodiments, the inner ring <NUM> may be configured such that the axial dimension <NUM> of the inner ring <NUM> is approximately double an axial height <NUM> of outer ring <NUM>. The outer ring <NUM> may be configured such that the radial dimension <NUM> of the end ring <NUM> is approximately double a radial width <NUM> of the outer ring <NUM>. In some embodiments, an outer surface <NUM> of the outer ring <NUM> may be substantially aligned with an outer surface <NUM> of the inner ring <NUM>. In other embodiments, the outer surface <NUM> of the outer ring <NUM> and the outer surface <NUM> of the inner ring <NUM> may not be substantially aligned such that a clearance between the outer surface <NUM> of the outer ring <NUM> and the valve bonnet <NUM> is different from a clearance between the outer surface <NUM> of the inner ring <NUM> and the valve bonnet <NUM>.

<FIG> illustrates an enlarged cross-sectional view of a portion of an embodiment of the stem packing (e.g., packing stack <NUM>). In some embodiments, the inner ring <NUM> and the outer ring <NUM> may define one or more clearances between the inner ring <NUM>, outer ring <NUM>, the stem <NUM>, and the valve bonnet <NUM>. In some embodiments, one or more of the clearances, e.g., discussed below, may provide voids positioned along a radial direction that, for example, enable radial movement of the valve stem <NUM>.

The inner ring <NUM> may define a stem clearance <NUM> between the inner ring <NUM> and the stem <NUM>. The stem clearance <NUM> may allow the stem to move (e.g., radially displace) relative to the end ring <NUM> and/or allow for thermal expansion of the components of the valve assembly <NUM> (<FIG>). In some embodiments, the stem clearance <NUM> may be configured to enable movement of the inner ring <NUM> relative to the stem <NUM>, for example, during assembly or disassembly, responsive to radial movement of the stem <NUM>, and/or responsive to the compressive forces exerted by the packing gland <NUM>. For example, once assembled, the packing gland <NUM> may be adjusted to increase or decrease pressure on the packing stack <NUM> by moving the packing gland <NUM> a distance toward or away from the packing stack <NUM>, which, in turn, may cause the end ring <NUM> to move toward or away from the packing rings <NUM>. In some embodiments, stem clearance <NUM> may be sized and configured to substantially prevent the packing material from the packing rings <NUM> from being extruded past the end ring <NUM> when the packing stack <NUM> is under compressive pressure from the packing gland <NUM> or fluid pressure within the valve body <NUM> (<FIG>). The stem clearance <NUM> may be between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), such as between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), or between about <NUM> in (<NUM>) and about <NUM> in (<NUM>).

In some embodiments, the inner ring <NUM> may define an outer clearance <NUM> between the inner ring <NUM> and the valve bonnet <NUM>. The outer clearance <NUM> may be configured to enable movement between the end ring <NUM> and the valve bonnet <NUM>, for example, the outer clearance <NUM> may allow the end ring <NUM> to move relative to the valve bonnet <NUM> responsive to the compressive forces exerted by the packing gland <NUM> when adjustments are made to the packing gland, during assembly or disassembly, responsive to radial movement of the stem <NUM>, and/or during operation. In some embodiments, the outer clearance <NUM> may be configured to enable for expansion and/or contraction of the inner ring <NUM>, the outer ring <NUM>, and/or the valve bonnet <NUM>. The outer clearance <NUM> may be between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), such as between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), or between about <NUM> in (<NUM>) and about <NUM> in (<NUM>).

In some embodiments, the inner ring <NUM> and the outer ring <NUM> may define a ring clearance <NUM> between the inner ring <NUM> and the outer ring <NUM>. The ring clearance <NUM> may be configured to enable the inner ring <NUM> and the outer ring <NUM> to expand and/or contract. In some embodiments, the ring clearance <NUM> may be configured to enable for different rates of thermal expansion between the inner ring <NUM> and the outer ring <NUM>. In some embodiments, the ring clearance <NUM> may be configured to allow movement between the inner ring <NUM> and the outer ring <NUM>, for example, during assembly and/or disassembly and/or responsive to radial movement of the stem <NUM>. The ring clearance <NUM> may be between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), such as between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), or between about <NUM> in (<NUM>) and about <NUM> in (<NUM>).

In some embodiments, the outer ring <NUM> may define a bonnet clearance <NUM> between the outer ring <NUM> and the valve bonnet <NUM>. In some embodiments, the bonnet clearance <NUM> may be configured to allow movement of the outer ring <NUM> relative to the bonnet <NUM>. For example, the bonnet clearance <NUM> may allow the outer ring <NUM> to translate relative to the valve bonnet <NUM> responsive to pressure applied by the packing gland <NUM> through the inner ring <NUM>, responsive to radial movement of the stem <NUM>, and/or for assembly or disassembly. In some embodiments, the bonnet clearance <NUM> may be configured to enable for thermal expansion and contraction of the outer ring <NUM> and the valve bonnet <NUM>. In some embodiments, the bonnet clearance <NUM> may be configured to substantially prevent the packing material of the packing rings <NUM> from extruding past an outer portion of the end ring <NUM>. The bonnet clearance <NUM> may be between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), such as between about <NUM> in (<NUM>) and about <NUM> in (<NUM>), or between about <NUM> in (<NUM>) and about <NUM> in (<NUM>).

In some embodiments, the combination of clearances <NUM>, <NUM>, <NUM>, and <NUM> may enable for each individual clearance <NUM>, <NUM>, <NUM>, and <NUM> to be relatively smaller while maintaining flexibility for expansion (e.g., thermal expansion), contraction, and/or movement between the different components of the bonnet assembly <NUM> (<FIG>) and/or the valve assembly <NUM> (<FIG>) (e.g., the valve stem <NUM>).

In some embodiments, the inner ring <NUM> may include one or more chamfered (e.g., rounded, beveled) edges. The chamfered edge may be configured to enhance movement between the inner ring <NUM> and the stem <NUM> (e.g., by reducing friction, by reducing the probability of inner ring <NUM> deforming due to movement of the stem <NUM>) and/or substantially prevent scoring (e.g., damaging, etching, carving, etc.) the stem <NUM>.

For example, an inner surface <NUM> of the inner ring <NUM> may be positioned proximate the stem <NUM> (e.g., directly adjacent). A distal inner edge <NUM> (e.g., further from the connection between the stem <NUM> and the valve element <NUM> (<FIG>)) and a proximal inner edge <NUM> (e.g., closer to the connection between the stem <NUM> and the valve element <NUM> (<FIG>)) may be located on opposite ends of the inner surface <NUM> of the inner ring <NUM> with the proximal inner edge <NUM> located adjacent to the packing rings <NUM>. In some embodiments, the distal inner edge <NUM> and the proximal inner edge <NUM> may both be chamfered in a direction away from the stem <NUM> (e.g., extending radially outward). In some embodiments, the chamfer on the proximal inner edge <NUM> and the chamfer on the distal inner edge <NUM> may be different. For example, the chamfer on the proximal inner edge <NUM> may be smaller or larger (e.g., in diameter, span, curvature, arc length, arc curvature, etc.) than that of the chamfer on the distal inner edge <NUM> of the inner ring <NUM>.

In some embodiments, an outer edge <NUM> may be located at an intersection between an outer surface <NUM> and a distal surface <NUM> of the inner ring <NUM>. In some embodiments, the outer edge <NUM> may be chamfered in a direction away from the valve bonnet <NUM>. In some embodiments, the outer edge <NUM> and the distal inner edge <NUM> may each be chamfered. In some embodiments, the chamfer on the outer edge <NUM> may have a different configuration (e.g., size, shape, curvature, angle, etc.) than the chamfer on the distal inner edge <NUM>. In some embodiments, the outer edge <NUM> and the proximal inner edge <NUM> may each be chamfered. In some embodiments, the outer edge <NUM>, the distal inner edge <NUM>, and the proximal inner edge <NUM> may all be chamfered. In some embodiments, at least one of the chamfers on the outer edge <NUM>, the distal inner edge <NUM>, and the proximal inner edge <NUM> may have different configurations.

<FIG> illustrate an embodiment of the inner ring <NUM>. The inner ring <NUM> may comprise an annular shape (e.g., circular, ring shaped). The inner surface <NUM> of the inner ring <NUM> may define an annular passage <NUM> (e.g., bore, opening, void) through the center of the inner ring <NUM>. The annular passage <NUM> may be complementary to the stem <NUM> (<FIG>). In some embodiments, the outer edge <NUM>, the distal inner edge <NUM>, and the proximal inner edge <NUM> of the inner ring <NUM> may comprise annular chamfered surfaces. In some embodiments, the inner ring <NUM> may include a shelf <NUM> and a locating surface <NUM>. For example, the inner ring <NUM> may have a first diameter defined by the outer surface <NUM> and a second diameter defined by the locating surface <NUM>. The second diameter may be smaller than the first diameter such that the shelf <NUM> is defined where the first diameter and the second diameter meet.

<FIG> illustrate an embodiment of the outer ring <NUM>. In some embodiments, the outer ring <NUM> may be annular. The outer ring <NUM> may include a retaining surface <NUM> and an inner surface <NUM>. The inner surface <NUM> of the outer ring <NUM> may define an inner void <NUM> (e.g., passage, bore, opening). In some embodiments, the inner void <NUM> may be configured to be complementary to the locating surface <NUM> (<FIG>) of the inner ring <NUM> (<FIG>). In some embodiments, the retaining surface <NUM> may be configured to rest against the shelf <NUM> (<FIG>) of the inner ring <NUM> (<FIG>).

Embodiments of the disclosure may include method of making and/or using such seals, packings, and valve assemblies. For example, a seal may be formed or defined in a valve assembly utilizing the packings discussed herein.

Valves according to embodiments of the present disclosure may provide significant improvements to valves used in high temperature and/or high pressure applications. Valves according to the present disclosure may include temperature resilient bonnet assemblies capable of being installed near the working fluid in high temperature applications. Packing stacks according to embodiments of the present disclosure may be capable of continuous service at temperatures in excess of <NUM>,<NUM>°F (<NUM>). Improved temperature resilience may enable valves used in high temperature applications to be constructed with the bonnet assembly proximate to the working fluid without the need for a portion of the assembly to dissipate heat from the working fluid. This in turn may enable smaller valve assemblies in high temperature and/or high pressure applications. Reduced valve sizes may further result in space savings in crowded applications as well as material and cost savings.

Valves according to embodiments of the present disclosure may provide significant improvements for use in high pressure applications as well. End ring assemblies with tight clearances may improve the ability of the end rings to retain packing material within the bonnet assembly at elevated pressures. For example, tight clearances enabled by embodiments of the instant disclosure may substantially prevent packing material from extruding past the end ring at elevated pressures. If packing material extrudes past the end rings it may result in catastrophic failure of the valve. At elevated pressures catastrophic failures have the potential for causing severe injuries or death and at the very least equipment damage and equipment down time. Providing tight clearances may increase the system pressures where the valves may be safely operated.

Claim 1:
A valve packing assembly, comprising:
a first end ring (<NUM>) comprising a first inner ring (<NUM>) and a first outer ring (<NUM>), the first end ring (<NUM>) configured to position the first inner ring (<NUM>) adjacent to a movable valve stem (<NUM>) of a valve (<NUM>) and to position the first outer ring (<NUM>) away from the movable valve stem (<NUM>);
a second end ring (<NUM>); and
a stack of adjacent sealing rings (<NUM>) configured to be positioned between the first end ring (<NUM>) and the second end ring (<NUM>),
wherein the first inner ring (<NUM>) defines an annular recess configured to retain the first outer ring (<NUM>) in a volume defined between the first inner ring (<NUM>), a body of the valve (<NUM>), and one sealing ring of the stack of adjacent sealing rings (<NUM>) positioned at one axial end of the stack of adjacent sealing rings (<NUM>);
wherein the first inner ring (<NUM>) and first outer ring (<NUM>) are enabled to move relative to one another in order to retain the stack of adj acent sealing rings;
characterized in that
the second end ring (<NUM>) comprises a second inner ring (<NUM>) and a second outer ring (<NUM>), the second end ring (<NUM>) configured to position the second inner ring (<NUM>) adjacent to the movable valve stem (<NUM>) and to position the second outer ring (<NUM>) away from the movable valve stem; and
wherein the second inner ring (<NUM>) defines an annular recess configured to retain the second outer ring (<NUM>) in a volume defined between the second inner ring (<NUM>), the body of the valve (<NUM>), and another sealing ring of the stack of adjacent sealing rings (<NUM>) positioned at another axial end of the stack of adjacent sealing rings (<NUM>); and
wherein the second inner ring (<NUM>) and second outer ring (<NUM>) are enabled to move relative to one another in order to retain the stack of adjacent sealing rings.