The present disclosure generally relates to fittings, such as fluid fittings.
This background description is set forth below for the purpose of providing context only. Therefore, any aspect of this background description, to the extent that it does not otherwise qualify as prior art, is neither expressly nor impliedly admitted as prior art against the instant disclosure.
With some fluid fittings, such as flareless fittings, it may be difficult to quickly determine if a sufficient connection has been made between a union, a nut, and/or a sleeve. For example, relative axial travel of a male and female flareless fitting between a minimum torque and a maximum torque may be about 0.0015 inches, and it may be difficult to ensure that a sufficient connection has been made, such as due to tolerance stack up. Using a torque wrench may involve an extended process.
There is a desire for solutions/options that minimize or eliminate one or more challenges or shortcomings of fluid fittings. The foregoing discussion is intended only to illustrate examples of the present field and should not be taken as a disavowal of scope.
In embodiments, a fluid fitting may include a nut, a sleeve, and/or a union. The union and the nut may include corresponding stops and/or corresponding markings. Corresponding stops may engage with each other when the nut is sufficiently connected with the union. Corresponding marking may at least partially align with each other when the nut is sufficiently connected with the union. Corresponding markings may include a first marking of the nut and a second visual indicator of the union. One of the first visual indicator and the second visual indicator may include a greater circumferential extent than the other. The corresponding markings may include a plurality of black lines
With embodiments, a method of connecting a fitting may include connecting a sleeve of the fitting with a nut of the fitting, connecting the nut with a union, rotating at least one of the nut and the union until a stop of the nut engages a stop of the union, restricting over torque via the stop of the nut and the stop of the union, and/or verifying a sufficient connection if first markings of the nut align with second markings of the union.
The foregoing and other aspects, features, details, utilities, and/or advantages of embodiments of the present disclosure will be apparent from reading the following description, and from reviewing the accompanying drawings.
Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the present disclosure will be described in conjunction with embodiments and/or examples, it will be understood that they are not intended to limit the present disclosure to these embodiments and/or examples. On the contrary, the present disclosure is intended to cover alternatives, modifications and equivalents.
In embodiments, such as generally illustrated in
In embodiments, a nut 40 may be connected with a sleeve 30. For example and without limitation, a nut 40 may include an inner surface or flange 42 that may engage a flange 34 of a sleeve 30 such that axial movement of the nut 40 in at least one direction (e.g., toward the union 60) may cause axial movement of the sleeve 30. An inner surface or flange 42 may be disposed at or about a rear end 44 of the nut 40. A nut 40 may engage a sleeve 30 such that the nut 40 may rotate relative to the sleeve 30 and/or such that the sleeve 30 may be restricted from moving axially relative to the nut 40 in at least one direction (e.g., away from the union 60). A nut 40 may include one or more flat portions 46 (or other formations) that may, for example, be configured for engagement with a wrench and/or a hand of a user to cause rotation of the nut 40. A nut 40 may include inner threads 48 that may be disposed at or about a front end 50 of the nut 40.
With embodiments, a union 60 may include a first connection portion 62 that may be configured to at least partially receive a portion of a sleeve 30. Additionally or alternatively, a first connection portion 62 may be configured for connection with a nut 40. For example and without limitation, first connection portion 62 may include an aperture or recess 64 for at least partially receiving sleeve 30, and/or may include outer threads 66 that may be configured to engage inner threads 48 of the nut 40. A union 60 may include a second connection portion 68 that may be configured in the same or a similar manner as the first connection portion 62. For example and without limitation, as generally illustrated in
With embodiments, a union 60 may include a shoulder 70 that may be disposed (e.g., axially) between the first connection portion 62 and the second connection portion 68. The shoulder 70 may include one or more flat portions 72 (or other formations) that may, for example, be configured for engagement with a wrench and/or a hand of a user. A shoulder 70 may include a greater outer diameter than the first connection portion 62 and/or the second connection portion 68.
In embodiments, a nut 40 may be connected to and/or disposed at least partially around a sleeve 30, and may then be connected to (e.g., screwed onto) a union 60. As a nut 40 connects with a union 60, the nut 40 may cause the sleeve 30 to move at least partially into an aperture 64 of the first connection portion 62 of the union 60, which may facilitate fluid communication between the sleeve 30, the fluid conduit 32, and/or the union 60.
With embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
With embodiments, a connection or engagement between stops, such as between a first stop 80 and a second stop 84, may provide a first visual indicator that a fluid fitting 20 is sufficiently connected. In embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
With embodiments, a range of expected deformation may be determined according to appropriate maximum and/or minimum limits (see, e.g.,
In embodiments, such as generally illustrated in
With embodiments, such as generally illustrated in
In embodiments, such as generally illustrated in
With reference to
Additionally or alternatively, with embodiments, verifying a sufficient connection (step 122) may include scanning a fluid fitting 20 with an optical device 96 (see, e.g.,
With embodiments, if a fluid fitting 20 is not sufficiently connected, the optical device 96 may not be able to read the barcode and/or the optical device 96 may provide an indication of an insufficient connection. An indication of an insufficient connection may include, for example and without limitation, an audible warning and/or a warning message that may be displayed on a display 98 of the optical device 96, among other types of indications.
With reference to
With embodiments, connecting the nut 40 with the union 60 may include rotating at least one of the nut 40 and the union 60 until the nut and the nut 40 and the union are finger-tight. A mechanical device, such as a wrench, may then be used for further tightening. Once the connecting (e.g., rotating) of the nut 40 and the union 60 ceases, the second stop 84 may, if over-torqued, be disposed at a different angular position AP.sub.2 than its initial position AP.sub.1 relative to the union 60. The fluid fitting 20 may subsequently be disconnected (step 142). With future or subsequent connections between the nut 40 and the union 60, the same or a greater amount of rotation, torque, and/or axial force (e.g., over-torqueing) may be used to cause engagement between first stop 80 and second stop 84 (step 144). That is, even if the second stop 84 moves from an initial position AP.sub.1, for example due to an associated deformation from connection, with subsequent connections the stop can ensure that the connection (with the second stop 84 at the subsequent position AP.sub.2) is sufficient. An over-torque condition may be detected if at least one of the first markings 90 rotates beyond a corresponding one of the second markings 92 before the stop 80 of the nut 40 engages the stop 84 of the union 60.
In embodiments, such as generally illustrated in
In embodiments, a stop angle 158 may be determined according to an expected plastic deformation, an expected elastic deformation, and/or an expected amount of axial compression of fitting 20. A stop angle 158 may be larger if an expected plastic deformation, an expected elastic deformation, and/or an expected amount of axial compression are relatively large. A stop angle 158 may be smaller if an expected plastic deformation, an expected elastic deformation, and/or an expected amount of axial compression are relatively small. A tolerance of a stop angle 158 may, for example and without limitation, be about +/−15 degrees to about +/−30 degrees, and/or about +/−25 degrees (e.g., with respect to relative positions of two stop features).
While a union 60 is shown with outer threads 66, and a nut 40 is shown with inner threads 48, embodiments of a fitting 20 may include a union 60 including inner threads engaging outer threads of a nut 40.
The sleeve 30, the nut 40, and the union 60 are generally described and illustrated as discrete components. However, some or all of such components (or features thereof) could be associated with components having different names (with similar configurations and/or functionality) and/or may be integrated and/or connected with one or more other/additional components. For example and without limitation, as would be known to persons of skill in the art, various configurations of such components may comprise a joint, and geometries that are referred to on a sleeve and a union may, for example, be formed (e.g., directly machined) into complex fittings or other/additional components.
With embodiments, a fluid fitting 20, which may be configured as a flareless fitting, such as a AS18280 style fitting, that may be used in connection with aircraft. Such fittings 20 may include one or more features that may be desirable and/or better than other designs, such as, for example and without limitation, improved or superior electrical conductivity, temperature range/compatibility, fluid and environmental compatibility, and/or reusability. A sufficient or correct connection of a flareless fitting may involve an acceptable range of torque, such as according to Aerospace Recommended Practice (ARP) 908. Some methods of evaluating a connection (e.g., via a torque value) may be an indirect measurement approach.
In embodiments, such as generally illustrated in
In
τ.sub.N=ε.sub.Nσ.sub.N Eq. 1
τ.sub.Nc=ε.sub.Ncσ.sub.N Eq. 2
0≤(ε.sup.2.sub.N+ε.sup.2.sub.Nc).sup.½≤μ.sub.N Eq. 3
P.sub.1=A.sub.N*B.sub.N*σ.sub.N*sin(φ.sub.N+θ.sub.N) Eq. 4
tan Φ.sub.N=ε.sub.N Eq. 5
B.sub.N=(1+ε.sub.N.sup.2).sup.½ Eq. 6
T.sub.S=τ.sub.c*A*r.sub.Nm Eq. 7
σ.sub.N=P.sub.1/(A.sub.N*sin θ.sub.N.sup.) Eq. 8
τ.sub.Nc=μ.sub.N*P.sub.1/(A.sub.N*sin θ.sub.N) Eq. 9
T.sub.S=μ.sub.N*rN.sub.m*P.sub.1/sin θ.sub.N Eq. 10
τ.sub.c=(μ.sub.N/sin θ.sub.N)(r.sub.Nm/r.sub.m)P.sub.1/A Eq. 11
τ.sub.c=ε.sub.cσ Eq. 12
ε.sub.c=(μ.sub.N/sin θ.sub.N)(r.sub.Nm/r.sub.m)(1+ε.sup.2).sup.½sin(φ+θ) Eq. 13
The following assumptions may be applied:
ε.sub.N=0 Eq. 14
ε.sub.Nc=μ.sub.N Eq. 15
φ.sub.N=0 Eq. 16
B.sub.N=1 Eq. 17
In connection with contact between a sleeve 30 and a union 60, σ may represent normal traction (e.g., sealing pressure), τ may represent friction traction along A, τ.sub.c may represent friction traction along a circumferential direction, A may represent sleeve-union contact area, A.sub.r may represent a radial projection of A, A.sub.a may represent an axial projection of A, k.sub.r may represent a radial stiffness, u.sub.r may represent radial displacement, u.sub.a may represent axial displacement, α may represent nut angular rotation (e.g., in radians), l.sub.t may represent a nut thread lead, T.sub.s may represent a sleeve torque, r.sub.m may represent a mean torque radius at sleeve-union contact, σ.sub.r may represent radial stress, and σ.sub.a may represent axial stress. These values/variables may be related according to the following equations:
τ=εσ Eq. 18
τ.sub.c=ε.sub.cσ Eq. 19
0≤(ε.sup.2+ε.sup.2.sub.c).sup.½≤μ Eq. 20
P.sub.2=A*B*σ*sin(φ+θ) Eq. 21
tan Φ=ε Eq. 22
B=(1+ε.sup.2).sup.½ Eq. 23
σ.sub.r=P.sub.2*sin(ψ×θ)/(A*cos θ*sin(Φ+θ)) Eq. 24
σ.sub.a=P.sub.2/(A*sin θ) Eq. 25
tan ψ=1/ε Eq. 26
σ.sub.r=k.sub.r*u.sub.r/A.sub.r Eq. 27
u.sub.r=u.sub.a*tan θ Eq. 28
u.sub.a=l.sub.t*α/(2π) Eq. 29
T.sub.S=τ.sub.c*A*r.sub.m Eq. 30
ε.sup.2+ε.sub.c.sup.2=μ.sup.2 Eq. 31
μ.sup.2×ε.sup.2=(μ.sub.N/sin θ.sub.N)(r.sub.Nm/r.sub.m)(1+ε.sup.2).sup.½sin(Φ+θ) Eq. 32
Equations 13 and 32 may be solved for F. A radial stress σ.sub.r, normal traction a (sealing pressure), and/or an axial force P.sub.1, P.sub.2, may be determined for a given nut rotation and radial stiffness. In embodiments, P.sub.1 may equal P.sub.2. Equations 18 and 19 may be solved for friction tractions at a sleeve-union interface. Equation 7 and/or Equation 30 may be solved for a sleeve torque T.sub.s. A nut torque T.sub.t due to threads may be determined, such as according to nut factor calculations. A total torque T may be represented as:
T=T.sub.S+T.sub.t Eq. 33
A nut axial force Pt may be represented as:
P.sub.t=K*T.sub.t*d Eq. 34
T.sub.t may represent a nut torque, K may represent a nut factor, and/or d may represent a nut average diameter. Nut factor K may include one or more effects of nut geometry as well as friction. During tightening, P.sub.t may equal P.sub.1 or P.sub.2 (which may be equal). During pressurization, P.sub.t may be different than P.sub.1 or P.sub.2.
One more assumptions may apply. For example and without limitation, it may be assumed that contact always occurs at constant angle and constant area, all tractions and stresses in sleeve nose are constant over area, interior shear stresses are negligible, radial stiffness is independent of angle, radial stiffness is uncoupled from other stiffness, union deformation is negligible (so radial displacement may be dictated by geometry u.sub.r=u.sub.a*tan(θ)), axial deformation of the sleeve 30 is negligible (so the sleeve 30 travels with the nut 40 like a rigid body u.sub.a=(1.sub.t/2*π)*α), a slip condition is present at the sleeve-nut bearing contact, frictional forces act only in the circumferential direction (which may be verified by finite element analysis or FEA), and/or a slip condition is present at the sleeve-union interface.
With some torque-based connection methods, a torque value may be related to an acceptable sealing pressure. In embodiments of methods of the present disclosure, a sealing pressure may be predicted. A relationship including all of the geometry of the mating components may be relatively complicated (e.g., as described above), but may be simplified to Equation 34. Axial force P.sub.t may be related to sealing pressure, such as via a geometrical relationship. A relatively small variation in friction can have a relatively significant effect on sealing pressure. For example and without limitation, a stainless steel ×4 fitting may be torqued to a minimum ARP 908 value of 135 in-lbs (15.25 Nm) with minimal lubrication and may have as low as 34,224 psi (236 MPa) of sealing pressure at the location of the gage point. Additionally or alternatively, that same connection with ideal lubrication may be torqued to a maximum allowable torque of 190 in-lbs (21.47 Nm) and may have as much as 175,547 psi (1210 MPa) of sealing pressure at the gage point, which may correspond to variation in excess of 100 ksi between connections.
With embodiments of the present disclosure, a desired sealing pressure may be maintained via control of a position of a nut 40 (e.g., rather than via torque values). Controlling a position of a nut 40 may include determining an appropriate lower specification limit (LSL), determining an appropriate upper specification limit (USL), determining manufacturing capabilities (e.g., associated with nut position placement), and/or determining inspection capabilities (e.g., associated with nut position placement).
In embodiments, an LSL may be determined according to one or more factors, such as component tolerances, temperature variation, repeated connections, and/or vibration. Increases in these factors may negatively impact sealing pressure. A minimum allowable sealing pressure (e.g., a theoretical minimum) may be determined as an LSL for nut position as one or more of these factors are evaluated and/or quantified.
In embodiments, a USL for nut position may be determined such that a torque involved to achieve a desired position may not exceed that of a typical or expected connection. A USL may be sufficiently low that galling may not occur and/or may be relatively insignificant.
With embodiments, fittings 20 may be designed to be compatible with conditions more severe than expected conditions, such as four times more severe than design operating pressure conditions.
In embodiments, a method of manufacturing and inspecting/verifying a fitting 20 may include directly dimensioning an axial position or angle of a gage point relative to thread position. The axial position of the gage point may be inspected, such as, for example and without limitation, via CMM (coordinate measuring machine) touch-probe technology and/or a CMM touch-probe machine. Embodiments of methods may include tightening tolerances.
Some methods of dimensioning/tolerancing may not be configured to establish proper nut positioning. For example and without limitation, with some methods, tolerance stack-ups may result in a variation of nut position in excess of one complete rotation.
In embodiments, angular stop position on a nut 40 and/or a union 60, in combination with a length of a sleeve 30, may control and/or dictate variation in nut position. As each component of a fitting 20 is designed, manufacturing and/or inspection capabilities may be evaluated (e.g., for compatibility with nut-position control methods). If manufacturing is not adequate for determined performance limits, one or more geometry changes may be made to the fitting 20 to influence the change of sealing pressure of the fitting 20 per turn of the nut 40. Geometry changes may include, for example and without limitation, (i) changes to a radius of a sealing surface, which may change a footprint at a gage point (a relatively small change in radius may provide a relatively large change in the sealing surface), (ii) changes to thread pitch, and/or (iii) changes to the inner diameter and/or outer dimeter of fitting components, which may change the stiffness of the fitting 20 (e.g., effectively a spring rate of the fitting system).
With embodiments, such as generally illustrated in
In embodiments, one or more components of a fitting 20 may be manufactured or formed with advanced machining methods and/or thread timing. With embodiments, a total tolerance stack of a fitting 20 may be about +/×0.003 inches, compared with other fittings that may include a total tolerance stack of about +/×0.038 inches. It may be desirable for relative axial travel to exceed a tolerance stack. Relative axial movement of components of a fitting 20 may exceed 0.003 inches. One or more wear resistant coatings may be applied to one or more components of a fitting 20, such as to limit or prevent galling.
With embodiments, one or more components of a fitting 20, such as a sleeve 30, a nut 40, and/or a union 60 may, for example and without limitation, be metal. Connecting a sleeve 30 with a union 60 may include forming a metal-to-metal fluid seal between the sleeve 30 and the union 60.
Various embodiments are described herein for various apparatuses, systems, and/or methods. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.
Reference throughout the specification to “various embodiments,” “with embodiments,” “in embodiments,” or “an embodiment,” or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “with embodiments,” “in embodiments,” or “an embodiment,” or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment/example may be combined, in whole or in part, with the features, structures, functions, and/or characteristics of one or more other embodiments/examples without limitation given that such combination is not illogical or non-functional. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the scope thereof.
It should be understood that references to a single element are not necessarily so limited and may include one or more of such element. Any directional references (e.g., plus, minus, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of embodiments.
Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily imply that two elements are directly connected/coupled and in fixed relation to each other. The use of “e.g.” in the specification is to be construed broadly and is used to provide non-limiting examples of embodiments of the disclosure, and the disclosure is not limited to such examples. Uses of “and” and “or” are to be construed broadly (e.g., to be treated as “and/or”). For example and without limitation, uses of “and” do not necessarily require all elements or features listed, and uses of “or” are intended to be inclusive unless such a construction would be illogical.
It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the present disclosure.
This application is a continuation of U.S. patent application Ser. No. 17/717,681, filed Apr. 11, 2022, which is a continuation-in-part application of U.S. patent application Ser. No. 16/043,737 filed on Jul. 24, 2018, which claims the benefit of claims the benefit of U.S. Provisional Patent Application Ser. No. 62/595,642, filed on Dec. 7, 2017, U.S. Provisional Patent Application Ser. No. 62/541,903, filed on Aug. 7, 2017, U.S., Provisional Patent Application Ser. No. 62/647,640, filed on Mar. 24, 2018, and U.S. Provisional Patent Application Ser. No. 62/662,945, filed on Apr. 26, 2018, the disclosures of which are all hereby incorporated herein by reference in their entireties.
Number | Date | Country | |
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62647640 | Mar 2018 | US | |
62595642 | Dec 2017 | US | |
62541903 | Aug 2017 | US | |
62662945 | Apr 2018 | US |
Number | Date | Country | |
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Parent | 17717681 | Apr 2022 | US |
Child | 18503968 | US | |
Parent | 16213151 | Dec 2018 | US |
Child | 17717681 | US |
Number | Date | Country | |
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Parent | 16043737 | Jul 2018 | US |
Child | 16213151 | US |