The present invention relates to a packing material for use with a fluid regulating device, and more particularly relates to a unitary packing material that is easy to mount within the fluid regulating device.
There exists in the art many different types of fluid regulating devices, including valves, regulators, differential pressure transducers and the like. Conventional fluid regulating devices, such as valves, are used in many different types of commercial applications to help regulate the flow of a fluid through a fluid conveyance system. Conventional valves come in many different shapes and sizes, and can include for example block or gate valves, control valves and the like. When used in commercial applications, the valves typically employ a mechanical packing material to help reduce fluid loss and the amount of unwanted gaseous emissions, such as volatile organic compounds (VOCs) that leak or are accidentally emitted from the valve.
Then packing material typically includes a plurality of separate packing elements or components that are axially stacked together about a movable valve stem. The packing material typically comes in rope form that is cut to size by the user. Each separate cut piece of packing material is mounted within the valve, and a plurality of pieces are stacked together. A gland follower can then be tightened so as to compress the packing material. As the packing material is compressed, it expands radially to create a seal between a dynamic valve stem and a stationary stuffing box. The seal formed by the packing components forms a fluid seal and maintains a pressure boundary between the fluid inside the valve and the external atmosphere.
A drawback of the conventional mounting techniques for the packing components is that the length of the packing material to be cut from a roll of packing material needs to be calculated, the number of packing components that are needed to be mounted within the valve needs to be determined, and then the user cuts the requisite number of packing components from the roll. The individual packing components are then individually mounted and stacked within the valve one at a time, with careful attention being paid to the orientation of the end of each ring of packing material. That is, each ring of packing material needs to be oriented such that the joint, seam or cut region is a selected number of degrees, such as 90° or 120°, away from the joint of the adjacent rings. This can be a time consuming process that requires some level of expertise.
It is therefore an object of the present invention to provide a unitary cartridge of packing material that includes a plurality of packing components that have been mechanically linked (e.g., compressed) together. The packing material cartridge can thus be mounted within the valve as a single, unitary component, thus simplifying the packing installation process. The orientation of each of the packing components is handled during formation or creation of the packing cartridge, and the user does not have to be concerned with the orientations of the separate packing components during installation.
The packing cartridge is formed by initially stacking together separate rings of packing material, each of which forms a packing component. The seams of each of the packing components are oriented relative to each other and in a selected manner so as to minimize fluid leakage therethrough. The stack of packing components are then compressed in opposite directions to form the packing cartridge. According to one embodiment, the invention can employ a two-step compression process using one or more press machines, such as a hydraulic press. The stack of packing components are placed within a die tool assembly that includes a barrel within an internal post. The individual and separate packing components are oriented and mounted within the barrel. Once other components of the die tool assembly of the present invention are assembled therewith, the stack of packing components are subjected to a compression force in a first direction for a selected amount of time, and then a second compression force in a second direction opposite to the first direction for a selected period of time. The compression forces can be applied simultaneously or sequentially. For example, after the first or initial compression force is applied and the released, the assembly can then be manipulated (e.g., reversed or flipped around) and selected die tool components can be added or removed. Once the assembly is complete, a second compression force is applied to the stacked and partially compressed packing components in an opposed direction for a selected amount of time. The bi-directional compression of the packing components creates a packing cartridge where the packing components comprising the cartridge are mechanically linked together through the compression forces applied thereto. The packing components forming the packing cartridge are difficult to separate once linked together. As such, the packing cartridge can be handled and installed within the valve as a single unitary assembly or unit.
The present invention is directed to a method of forming a packing cartridge from a plurality of packing components comprising placing a plurality of individual packing components in a stacked manner in a die tool assembly; compressing the plurality of packing components in a first direction; and compressing the plurality of packing components in a second direction opposite the first direction to form the packing cartridge. The plurality of packing components forming the packing cartridge are mechanically linked together. The method further includes removing the packing cartridge from the die tool assembly as a unitary assembly. The packing components are mechanically linked together free of a fastening devices or an adhesive to form the packing cartridge.
The method also includes, after the step of compressing the plurality of packing components in the first direction, manipulating (such as positioning, orienting, reorienting, reversing or the like) the die tool assembly so that the packing components can be compressed in the second direction. The die tool assembly includes a barrel component having a chamber, a seat element disposed in the chamber, and a post disposed in a chamber of the seat element. The plurality of packing components are disposed within the chamber of the barrel component. The die tool assembly can optionally include first and/or second stop elements that are in contact with top and/or bottom surfaces of the barrel component, respectively.
The compression forces can be applied to the plurality of packing components for a selected period of time. For example, the compression forces can be applied to the plurality of packing components for a time period between about 1 second and about 90 seconds. Further, the density of each of the plurality of packing components forming the packing cartridge is between about 1.2 g/cc and about 2.5 g/cc.
According to another practice, the present invention includes a method of forming a packing cartridge from a plurality of packing components, comprising placing a plurality of individual packing components in a stacked manner in a die tool assembly, compressing the plurality of packing components in a first direction, orienting the die tool assembly to compress the plurality of packing components in a second direction opposite to the first direction to form the packing cartridge, wherein in the packing cartridge the plurality of packing components are mechanically linked together, and removing the packing cartridge from the die tool assembly as a unitary assembly. The packing components are mechanically linked together free of a fastening devices or an adhesive to form the packing cartridge.
According to still another practice, the present invention is directed to a packing cartridge suitable for use with a fluid regulating device, comprising a cartridge main body composed of a plurality of packing components that are stacked together to form the packing cartridge, where the packing components are mechanically linked together free of a fastening device or adhesive. The density of each of the packing components forming the packing cartridge is between about 1.2 g/cc and about 2.5 g/cc.
Further, each of the plurality of packing components comprises a plurality of packing strands that are braided together, wherein each of the packing strands includes one or more packing yarns disposed within a reinforcing element. According to one embodiment, the packing yarn is formed of graphite, and the reinforcing element is a wire mesh composed of metal.
These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawings in which like reference numerals refer to like elements throughout the different views. The drawings illustrate principals of the invention and, although not to scale, show relative dimensions.
The present invention is directed to a mechanical packing material suitable for use with a fluid regulating device for reducing or minimizing leakage therefrom. As used herein, the term “fluid regulating device” is intended to encompass any selected device that helps, assists, prevents, or regulates the flow of a fluid through a fluid transport or conveyance medium, such as a pipe. The fluid regulating device is preferably of a type that employs a packing material, and can include valves, regulators, and the like. When a valve is employed, the valves can have any selected size and shape, and can include for example a hydraulic valve, a manual valve, a pneumatic valve, a solenoid valve, or a motor valve. Types of valves that are suitable for use with the present invention can include a block valve including a gate, butterfly, ball and plug valves, a control valve, or a check valve including quarter turn and globe valves. Those of ordinary skill will readily recognize that the packing material of the present invention can also be used with mechanical seals.
The illustrated handwheel 32 is coupled to one end of a vertically movable valve stem 36. The handwheel when rotated serves to move the valve stem 36 upwards and downwards in a vertical directions depending upon the direction of rotation of the wheel. The valve stem 36 is coupled at the other end to a valve wedge assembly 42 that is disposed in the chamber 14. The valve wedge assembly 42 serves to regulate the flow of fluid passing through the body 12 depending upon the position of the assembly 42 within the chamber 14, as is known in the art. The gland and flange portion 30 can include a flange or gland element 46 that seats against a packing material cartridge 50 that is mounted therein. The gland element 46 can be moved in the vertical direction by tightening the gland bolts 48, 48. When the gland bolts are tightened, the packing material cartridge 50 is further compressed by the gland element 46, as is known in the art. The packing material cartridge 50 is intended to form a fluid tight seal with the valve stem 36. The packing material cartridge 50 can be composed of a series or plurality of axially abutting packing rings or components, which are wrapped around the valve stem shaft and provides an interface and dynamic sealing surface between the shaft and the remainder of the fluid regulating device. Over time, the packing material cartridge 50 tends to decompose and lose volume, thus allowing emissions to escape the valve. In order to address the unwanted loss of volume and hence the increase in fugitive emissions, the operator of the valve can typically compress the packing cartridge further via the gland bolts 48, 48.
The packing material cartridge 50 of the present invention can include a plurality of individual packing components 54 that are generally ring shaped and formed of a packing material. The packing material typically comes in rope form that is cut to size by the user. The packing material is then shaped as a ring. The packing material cartridge 50 is formed by initially stacking together separate packing components 54. The seams of each of the packing components are oriented relative to each other and in a selected manner so as to minimize fluid leakage therethrough.
The packing components 54 of the packing material cartridge 50 of the present invention can have any selected shape and size, and can be formed in an interbraid pattern or a square braid pattern, or any other suitable braiding pattern known to those of ordinary skill in the art. The packing component 54 may be in the form of a braided material that is commonly square or round when viewed in cross section, although the packing component 54 may be provided in a variety of cross-sectional shapes. Multiple packing components 54 may be provided along the length of the valve stem shaft 36 in order to provide a seal around the shaft. Although the present invention can be employed with any suitable type and shape of packing material, for the sake of simplicity a square braid pattern is shown in
The packing material cartridge 50 of the present invention can be formed by employing a die tool assembly 70 according to the teachings of the present invention. Specifically, the present invention contemplates forming a single packing material cartridge from a plurality of packing components 54 by compressing the packing components in opposed directions either simultaneously or sequentially. For example, the present invention can employ a single step or a multi-step compression process for applying a compression force to the packing components from both axial or radial directions. Those of ordinary skill in the art will readily recognize that the illustrated die tool assembly 70 of the present invention is merely exemplary and can have any selected configuration or employ different parts than those illustrated herein without departing from the scope of the present invention. For the sake of simplicity, a multi-step compression process is described below. As shown in
The die tool assembly 70, once assembled, is shown in
As shown in
The fully assembled and packed die tool assembly 70 is then disposed beneath a suitable press machine 110, such as a hydraulic press. Although a single press machine is illustrated, those of ordinary skill will readily recognize that multiple opposed press machines can also be used for bi-directional compression. The illustrated hydraulic press includes an axially movable pressing component, such as the axially movable piston 112. The piston 112, when actuated, contacts the top surface 98A of the pusher element 98. The bottom surface 98B of the pusher element when under pressure axially moves the packing components 54 and the seal element 76 axially downward until the seat element 76 reaches the support surface that contacts the bottom surface 92B of the stop element 92,
As shown in
The packing cartridge 50 is then removed from the die tool assembly 70. As shown in
Once the packing components 54 have been compressed in opposite directions, the resultant packing cartridge 50 needs to be removed from the die tool assembly 70. In addition to the exemplary process illustrated in
The resultant packing material cartridge 50 is shown in
The compression of the packing components 54 in opposite directions as described above to form the packing material cartridge 50 ensures that the individual packing components comprising the cartridge have the same degree of compression and do not substantially vary in height. If the stack of packing components 54 within the die tool assembly 70 are only compressed in a single direction, the compressed height of each packing component increases from the top to the bottom, indicating that the packing components undergo uneven compression. By applying the compression force to the stacked set of packing components in the opposite direction, the packing components undergo more even compression across the stack. This results in packing components having generally the same height, that is, within about 0.01 inches of each other. The density of each of the packing components forming the packing material cartridge is between about 1.2 g/cc and about 2.5 g/cc, preferably between about 1.8 g/cc and about 2.2 g/cc, and most preferably about 2.0 g/cc. Moreover, compressing the packing components 54 within the die tool assembly 70 helps retain the dimensional stability of the resultant cartridge. The present invention also contemplates the use of a non-braided packing material or component, or a packing component that employs braided and non-braided material or components.
The invention is described herein relative to illustrated embodiments. Those skilled in the art will appreciate that the present invention may be implemented in a number of different applications and embodiments and is not specifically limited in its application to the particular embodiment depicted herein.
The terms “axial” and “axially” used herein refer to a direction generally parallel to the axis of a shaft or refers to vertically up or down. The terms “radial” and “radially” used herein refer to a direction generally perpendicular to the axis of a shaft or side to side. The terms “fluid” and “fluids” refer to liquids, gases, and combinations thereof.
It will thus be seen that the invention efficiently attains the objects set forth above, among those made apparent from the preceding description. Since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are to cover all generic and specific features of the invention described herein, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
This application is related and claims priority to provisional patent application Ser. No. 62/647,362, filed on Mar. 23, 2018, and entitled Packing Material Cartridge, the contents of which are herein incorporated by reference.
Number | Date | Country | |
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62647362 | Mar 2018 | US |