Patent Application
20180355975
The present invention relates to fluid coupling assemblies such as rotary unions and will be particularly described in relation to an extended life swivel seal assembly and, more specifically, to an extended life swivel seal assembly for use in a fluid coupling for high speed geological drilling operations.
Fluid coupling assemblies are used in industrial applications, for example, in high speed drilling operations where it is necessary to couple the outlet of a fluid source to a rotating device, machining of metals or plastics, work holding, printing, plastic film manufacture, papermaking, semiconductor wafer manufacture, and other industrial processes that require a fluid medium to be transferred from a stationary source such as a pump or reservoir into a rotating element. Often these applications require high media pressures and flow rates.
Fluid coupling assemblies used in such applications convey fluid medium used by the equipment for drilling, cooling, heating, or for actuating one or more rotating elements. Typical fluid media include water-based liquids or slurries, or hydraulic or cooling oils. Machines using fluid coupling devices typically include components that are expensive and/or difficult to repair or replace during service. These components are often subject to corrosive environments or to damage.
Specifically, in oil and gas drilling operations, fluid coupling assemblies, often called “swivel seal assemblies,” are utilized to provide a sealing arrangement between the washpipe and the rotating sealing housing. One type of a drilling rig swivel seal assembly utilizes a stack of rotary seals which are typically comprised of reinforced elastomeric material that provide a dynamic sealing arrangement with the external cylindrical sealing surface of the washpipe. In certain applications, the working fluid is a mud slurry. In such designs, the seals and their housings rotate relative to the stationary washpipe, and the seals are sequentially exposed to the high pressure drilling fluid on one side of the seal and atmospheric pressure on the other side of the seal. This differential pressure causes the seal closest to the high pressure to grab tightly against the washpipe, thereby causing a high degree of wear and abrasion to the washpipe and the seal. The wear and abrasion is exacerbated by grit particles from the mud slurry that enter the sliding interface between the rotary seals.
The relatively large clearance required between the rotating seal and the washpipe results in ultimate failure of the seal. Additionally, because of the stacked relation of the seals to the washpipe, once the first seal fails, the next seal in the stack is exposed to similar forces and wear, and so on, until all the seals have been consumed by the severe abrasive operating conditions. Such rotary seal members are also structurally complex, are time consuming and difficult to replace, and have a limited lifetime of approximately 200 hours or less when operating at 90 RPM and up to 2,500 PSI. When such seal assemblies are operated at 5,000 PSI and at 250 RPM, such seals last only between 20 and 30 hours before replacement is necessary.
An additional sealing arrangement is the utilization of complex U-shaped cup ring sealing assemblies between the washpipe and the rotating seal assembly. However, such sealing assemblies also have a limited lifetime and require significant replacement costs due to wear and abrasion which results in extended downtime of the drilling swivel seal assembly.
It has also been suggested to provide a floating seal member attached to the rotating coupling member and a similar seal member mounted to the non-rotating coupling member to provide a seal assembly for a drilling rig swivel assembly. Such seal assemblies further include a secondary seal member comprised of a U-cup seal member between the distal end of the washpipe member and the floating seal member. However, because the U-cup seal member is exposed to the high pressure abrasive drilling fluid, such contact results in the rapid wear and ultimate failure of such fluid coupling assemblies.
In one aspect, the disclosure describes a fluid coupling assembly. The fluid coupling assembly includes a rotatable component, a first sealing ring engaged with the rotatable component, the first sealing ring being rotatably constrained to the rotatable component, and a non-rotatable component having a second sealing ring engaged with the non-rotatable component, the second sealing ring abutting the first sealing ring to create a sliding seal interface therebetween. A fluid conduit is defined that extends through the rotatable component, the first sealing ring, the second sealing ring and the non-rotatable component. During operation, a flow of fluid is provided through the fluid conduit. The fluid coupling assembly further includes a hydrocyclone device having a body forming a cyclone chamber, the cyclone chamber having a feed opening, a base opening and an apex opening. A flow constrictor is disposed along the fluid conduit between an upstream portion and a downstream portion of the fluid conduit. The feed opening is fluidly connected to the upstream portion of the fluid conduit, and the apex opening is fluidly connected to the downstream portion of the fluid conduit. The base opening is fluidly connected to a passage having an outlet adjacent the sliding seal interface.
In another aspect, the disclosure describes a method for operating a fluid coupling assembly. The method includes providing an assembly having a rotating component that rotates relative to a non-rotating component, creating a sliding seal interface between the rotating and non-rotating components, and providing a flow of fluid through a fluid conduit extending through and between the rotating and non-rotating components. The method further includes fluidly connecting a hydrocyclone in fluid communication with the fluid conduit, the hydrocyclone including a feed opening, a base opening and an apex opening in fluid communication with a cyclone chamber, diverting a portion of the flow of fluid, and providing the portion of the flow of fluid to the cyclone chamber through the feed opening. The method also includes separating the portion of the flow of fluid in the cyclone chamber into a heavy material flow, which is expelled from the apex opening of the cyclone chamber, and a light material flow, which is expelled from the base opening of the cyclone chamber, and routing the light material flow to an area adjacent the sliding seal interface.
In yet another aspect, the disclosure describes an insert for a fluid coupling assembly, which includes a flange and a body connected to the flange. The body has a generally cylindrical shape and includes a through opening extending through the body and a channel extending peripherally around the body at a distance from the flange. A plurality of hydrocyclones is formed in the body, each of the plurality of hydrocyclones including a cyclone chamber defined in the body, the cyclone chamber having a feed opening, a base opening and an apex opening. In one embodiment, the feed opening is fluidly connected to a feed passage formed in the body and communicates with an inlet opening formed in a surface of the flange that is opposite the body portion, the base opening is fluidly connected to a water passage formed in the body and communicates with an outlet opening formed in a lateral surface of the body that is disposed within the channel, and the apex opening fluidly communicates with a heavy material discharge formed in an end surface of the body opposite the flange.
This disclosure relates to fluid coupling assemblies such as a seal assembly used in a water based drilling mud swivel seal assembly. As will be understood by those skilled in the art, this disclosure can be adapted for use with conventional rotary unions that typically include a stationary member, sometimes referred to as the housing, which has an inlet port for receiving fluid medium. In an exemplary rotary union, a non-rotating seal member is mounted within the housing. A rotating member, which is sometimes referred to as a rotor, includes a rotating seal member and an outlet port for delivering fluid to a rotating component. A seal surface of the non-rotating seal member is biased into fluid-tight engagement with the seal surface of the rotating seal member, generally by a spring, media pressure, or other method, thus enabling a seal to be formed between the rotating and non-rotating components of the union. The seal permits transfer of fluid medium through the union without significant leakage between the non-rotating and rotating portions.
For sake of brevity, the disclosure will be described in relation to a swivel seal assembly, though it should be understood that the disclosure has application to other fluid coupling devices such as rotating unions used with equipment such as computer-numerical-control (CNC) milling machines, turning machines, and so forth. A swivel seal assembly 100 is shown in
A floating seal guide member 116 is aligned with the washpipe and configured to slidably and sealably engage therewith to control a loading applied onto the sliding seal interface. Pins 118 and a spring 120 axially constrain and bias the floating seal guide member 116 and, thus, the sealing rings 102, towards one another. Anti-rotation pins 122 rotatably engage a respective one of the sealing rings 102 with the guide member 116 and the rotating drill string 114 to ensure that one sealing ring rotates with the drill string and the other remains rotationally stationary and engaged with the guide member 116.
A cross section of a swivel seal assembly 200 in accordance with the disclosure is shown in
Advantageously formed in the cylindrical body 206 are one or more hydrocyclones 216, which in an embodiment are arranged symmetrically around a periphery of the through opening 208. In the illustrated embodiment, the hydrocyclones 216 are integrated with, formed within, or otherwise associated with the body portion 206 of the insert 202. As shown in the cross section of
In the embodiment illustrated in
In reference to
The pressure difference between the upstream and downstream ends 306 and 308 drives the portion 302 of fluid to enter the passage 228 through the inlet port 226 and, in turn, to enter the cyclone chamber 218 of each respective hydrocyclone 216 via each corresponding feed or tangential opening 224. Within the chamber, cyclonic action causes a separation of at least some of the heavier grit components from the portion 302, which collect into a heavier mud flow 310 that exits the chamber through the apex opening 222 and rejoins the remaining portion 304 of the flow. Lighter compounds and water exit the chamber through the base opening 220 and are carried via passage 228 to the water outlet 230.
The lighter compounds and water 312 exiting the water outlet 230 collect in the gap 210 and displace the heavier mud slurry from the main flow 300 that would have otherwise occupied this space, and provide a more favorable environment for operation of the sealing rings 102. Specifically, by providing water or, at least, thinner drilling mud around the area of the seals, large, abrasive mud particles are diverted from reaching the sliding interface between the sealing rings to reduce abrasive wear of the sealing rings and to prolong their service life. This is accomplished by separating and providing water to the seals in situ, which also operates to cool and lubricate the sealing rings. Due to the pressure difference across the device provided by the throttling function of the through opening 208, a constant flow of water or, at least, a thinner aqueous solution is provided in a positive flow arrangement into the gap 210. Excess fluid from the flow 312 exits the gap 210 around the lower flange 214, which is sized such that ingress of heavier mud into the gap 210 is countered by the flow of water or thinner slurry 312. Further, it can be appreciated that the only fluid pressure to which the system is exposed to is the pressure difference created by the through opening 208 and not the operating, system pressure because the structures and passages are all internal to the device. This same arrangement can be applied to other fluid coupling assemblies to lubricate the sealing rings to reduce abrasion and wear.
An alternative embodiment showing an external packaging of a hydrocyclone 216 is shown in the schematic view of
More specifically, the first sealing ring 500 includes an outer ring 504 that surrounds an inner ring 506. As shown, the outer ring 504 may be constructed of metal such as stainless steel, and the inner ring 506 may be constructed of an appropriate sealing material such as a polymer or a polymer-based composite material such as the material available in commerce under the name Celazole® TL-60, available from PBI Performance Products, Inc. of Charlotte, N.C. (www.CelazolePBI.com), or another appropriate material depending on the application. The outer ring 504 includes recesses 508 into which pins (not shown) are inserted to either prevent rotation of the ring relative to a stationary component or to rotatably engage the ring to a rotating structure. The inner ring 506 includes a base portion 510, which has a generally rectangular cross section, and a sealing portion 512, which has a generally trapezoidal cross section.
The sealing portion 512 presents an annular sealing face 514 that protrudes past the base portion 510 and is surrounded by two conical surfaces extending radially inwardly and outwardly. As shown in
Similar to the first sealing ring 500, the second sealing ring 502 includes an outer ring 524 that surrounds an inner ring 526. As shown, the outer ring 524 may be constructed of metal such as stainless steel, and the inner ring 526 may be constructed of an appropriate sealing material such as a polymer or a polymer-based composite material, similar to the inner ring of the first sealing ring or another appropriate material depending on the application. Like the outer ring 504 of the first sealing ring 500, the outer ring 524 of the second sealing ring 502 includes recesses 508 into which pins (not shown) are inserted to either prevent rotation of the ring relative to a stationary component or to rotatably engage the ring to a rotating structure. The inner ring 526 includes a base portion 530, which has a generally rectangular cross section, and a sealing portion 532, which has a generally trapezoidal cross section.
The sealing portion 532 presents an annular sealing face 534 that protrudes past the base portion 530 and is surrounded by two conical surfaces radially extending inwardly and outwardly. As shown in
A flowchart for a method of operating a swivel seal assembly is shown in
The method further includes disposing a hydrocyclone in fluid communication with the fluid passing through the conduit at 610, which includes providing a hydrocyclone having a cyclone chamber that is fluidly in communication with a feed opening, a base opening and an apex opening in fluid communication with the fluid conduit. During operation, the method further includes separating a portion of the flow of fluid passing through the fluid conduit, and providing the portion of the flow to the hydrocyclone through the feed opening at 612. At 614, fluid entering the cyclone chamber separates into a heavy material flow that exits the apex opening and a light material flow that exits the base opening. The fluid is urged to pass into and through the cyclone cavity under a pressure difference that is created within the fluid conduit across at least the feed opening and the apex and/or base openings of the hydrocyclone. The heavy material flow is routed back into the fluid conduit to mix with a remaining portion of the fluid flow at 616. The light material flow is routed and delivered close to the sliding seal interface at 618 to lubricate and cool the sealing components that create the sliding seal interface. At 620, the light material flow is also provided back into the fluid conduit after it has washed over the sliding seal interface. The process of separating a portion of the flow, at least partially, into its constituents, continues while the device is operating and while a flow of fluid is provided through the fluid conduit.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. Specifically, preferred embodiments of this disclosure are described herein, including the best mode known to the inventor at this time for carrying out the disclosure. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/516,424, filed on Jun. 7, 2017, which is incorporated herein in its entirety by this reference.
| Number | Date | Country | |
|---|---|---|---|
| 62516424 | Jun 2017 | US |
