Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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"~UIGI~-CONNECT COUPLING FOR THIN-~ALLED PIPES"
FIl~LD OF THE INVENTION
This invention relates to a coupling for pipeline assemblies
employed for conveying fluids under pressure, and in particular re]ates to
a coupling known in the art as a quick-conllect coupling comprising coupling
members of segmented, usually semi-circular configuration which are
employed to bridge the mutua1l~7 presented ends of a pair of pipes in sealing
relationship, and secure the pipes against movement relatively to each other.
Such quick-connect couplings are clampingly engaged with the
outer periphery of the pipe ends, an~ convenient arrangement such as bolts
and nuts or lever actuated toggles being employed for securing the
respectively clamping mernbers to each other, and~ for providing the required
clarnping pressure on the pipes.
In order to provide for sealing of the pipe ends to each other
and to prevent leakage or seepage of the pressurized fluid within the pipes
in a direction either radially of the pipe ends or axially along the outer
periphery thereof, either a single annular gasket member of an elastomeric
material is positioned over the pipe ends in bridging relationship therewith
prior to the coupling members being applied to the pipe ends, or, the
respective coupling members are provided with gasket members of
elastomeric material which are supported by the coupling members and
which are brought into the required bridging and sealing relfltionship with
the pipe ends upon the positioning of the coupling members over the pipe
ends and the securing of the coupling members to each other. In either
case, the couplinrr members are provided with a central groove within which
the e}astomeric seal is received, the elastomeric seal being held under
compression by the coupling members against the outer surface of the pipe
ends.
Couplings of the type described above are known from United
States Patent Serial No. 2,0~11,132, Johnson, issued May 19, 1936, in their
utility in securing and sealing to each other the ends of thin-walled pipes
formed from a material which is capable of being worked to provide locating
members after formation of the pipes. In Johnson, the pi?e ends are worked
subsequent to the formation of the pipe to provide circumfercntiall~ spaced
radia]ly c~:tending arcunte projectioI7s on each of the adjacent pipe ends,
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the arcuate projections being r eceived within flnd held by interllal grooves
located within and adjacent each axifll end of the coupling members. l~hen
the coupling members are properly assembled about the pipc ends, the
nrcl~ate projections are trapped within the grooves of the cOUplil~g members,
rmd provide limited axial movement of the pipes relatively to each other,
while restrainin~ them from separation.
BACKGRQUND OF T~E I~VENTION
In numerous industrial applications, such as in food or che;nical
processing plants, and, in particular wood pulp handling and processing plants
and paper manufacturing plants, the need arises to employ pipes formed
from a material which is highly resistant to corrosion or etching by the
conveyed fluids; and which is non-reactive with the fluid to be conve~ed
and non-contaminating to that fluid. Stainless steel commonly is employed
for this purpose. However, stainless steel is a high cost material requiring
economies to be effected in its usAge. ~s a consequence, the wall thickness
of the pipes must be Icept as small as is possible withill the design and
operating parameters of the plant, it being uneconomical to employ stainless
steel pipes of a maxirnum wall thickness, except in those circuln~stances
which require maximum wall thickness. Commonly, such pipes formed from
stainless steel are of a relatively light gfluge and have a wall thickness in
the range of 0.078 to 0.109 inches, the range not necessarily being limited
to such thickness.
While such selection of rninimal wall thicl;ness of the pipes is
admirable for the reasons of economy, it tends to preclude the use of
quicl;-connect couplings, in that a quicl;-connect coupling of specific
dimensions must be provided for any specific wall thickness of pipe.
This requirernent arises in that the end faces of the coupling
menlbers must be brought in to face contact with the faces of the oppos te
coupling member, for otherwise, there will be a gap existing between the
mutually presented pairs of end faces wllich will permit the extrusion or
coid flow of the g~sket melnber at the interface of the coupling members,
with A conscyuential loss of sealing pressure exerted on the elastomeric
seal nnd seepage axially of the pipe ends, and, seepage at the radial
interface of the gasket members in those instances ~ here the elastorneric
seal is other thar conti nuous.
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This condition will arise when the outside diameter of a pipe
is greatcr than that for which the coupling was designed. In the event
that the outside diameter of the pipe is less than that for which the
coupling was designed, then the end fAces of the coupling members will
come into face contacl with each other, but, prior to the required
compressive force being developed within the gasket member sufficient to
ensure against seepage axially of the elastomeric seal or radially at the
interface of the respective ends thereof.
Further, in the event that a coupling is applied to a pipe
having an outside diameter which is less than that for which the coupling
was designed, and the pipe is of the type having spaced radially extending
arcuate projections for interlocl~ing with the couplinq, then, the
interengagement between the projections and the coupling will be of
diminished extent and will reduce the strenath of the interconnection.
OB~ECT OF Tl-IE INVENTION
It is an object of this invention to provide a quick-connect
coupling which can be employed univelsally with pipes of ally ~vall th;cl;ness
within a determitled range, thus eliminating the necessity of providing a
coupling of specific dimensiorls to accommodate any particular wall thickness
of pipe within that determined range.
SUMMARY OF THE INVENTION
According to the present invention, instead of being formed
from coupling members in which the end faces of each coupling member
are coplanar with the axis of generation of the couplingr member as in prior
known constructions, the end faces of the coupling members are formed
for them to be substantially planar and for each said end face to lie in a
plane which is parallel to, but spaced from, a radia] plane ~hich includes
the central longitudinal axis of generation of the coupling bore and which
lies beyond the associated end of the coupling member.
Where the coupling member is comprised of t~o coupling
member hlllves, as is most commonly the case, the respective end faces
of each coupling member are coplanar, and the plane of the end faces is
spaced from the axis of generation of coupling member half with said axis
positioned on that side of said plane which is opposite to the side facing
the COllp]ing member half. An extrusion shie]d in two parts, of fle~;ible
:~ t yet som ewh~t rigid m eteriel is provi ded ~ the ol~ ter ;a ce of the
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elastomeric gasket mernber, the extrusion shield bridging any gap which
may be present between the mutually presented end faces of the coupling
members tllus maintflining the compressive for ce exerted on the gasket
member and confining the elastomeric seal against exh~usion.
As will be apparent later in the discussion of the present
invention, the compressive force exerted on the gasket member is maintained
at or above fl minimurn optimum level without regard to the wa!l thickness
of the pipe ~Yithin a determined range of thicknesses, advantage being taken
of the ability of the pipe to flex and deform for it to be of other than
truly circular transverse cross-section.
DESCRIPTION OF THE l)RAWINGS
The invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 is a perspective view of a quick-connect
coupling according to the present invention
applied to the ends of a pair of pipes;
Figure 2 is a fragmentaly cross-section take
along the line 2-2 in Figure 1;
~igure 3 is a cross-section takell along the line
3-3 in Figure 2 and showing the coupling of the
present invention applied to a pipe having a
maximum permissible ~all thickness; :
Figure 4 is a transverse cross-section taken on
the line 4-4 in ~igure 2, again showing the
coupling of the present invention applied to a
pipe having maximum permissible wall thicl;ness;
Figures 5A and 5B are transverse cross-sections
corresponding with Figllre 3, but showing tlle .
collpling of the present invention appLied to a
pipe having minimum ~flll thickness, Figure SA ~;
showing the coupling assembled about the pipe
end but prior to torquing of the bolts, and figure
5B showing the coupLing assembled about the pipe
end and subsequent to the torquing of the bolts;
Fi~rure 6 is a transverse cross-section corre-
sponding with Ficure 4, showing the coupling of
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the present invention app~ied to a pipe of minimfll
wall thickness;
Figul e 7 is a fragmentary cross-section similar
to Figure 2, but illustratng a flanged quick-
connect coupling nccording to the present
invention applied to the end of a single pipe;
Figure 8 is a fragmentary perspective view of
the sealing gasket employed in the flanged
coupling of Figure 7; and,
Figure 9 is a fragmentary perspective view of
an alternative form of sealing gasket for use in
the quick-connect coupling of any one of Figures
1 through 6.
Referring now to the drawings, the quicli-connect coupling of ;
the present invention is indicated generally by the referellce numeral lO,
the coupling being shown as applied to, and interconnecting the ends of
pipes ll and l~. The coupling is comprised of coupling member halves l~
which are identical witll each other in aU respects in the cflse of pipes
having an internal diameter which is identical with that of the internal
diameter of the other pipe, as is most com monly the case. The present
invention does not, however, preclude a ste~up or step-down in the internal
diameter of the respective pipes.
In relation to the flpplication of the invention as a step-up or
step-down coupling, in the practical case it is not necessary that the wall
thickness be identical if one is willing to accept some tilting of the coupling
and in fact even in pipes of common internal diameter but different wall
thicknesses, it has been proven practical to use the coupling, for e7~ample~
to join a pipe of .078" wall to a pipe of .109" wall. Further with regard to
the abilities of the coupling, it should be recognized that the coupling can
also be used to accomodate pipe of a specific wall thickness but with O.D.
variations, e.g. due to tolerances lying w ithin the design range of the
coupling.
The respective coupling member halves may be formed in any
s~1itable manner, such as b~7 casting or forging, and, may be formed of any
suitable material, such as cast or malleable iron or steel. Where conditions
warrant, the coupling mernber halves may be formed from a materi~l
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identical with that of the pipes, ior example, stainless steel. Optionally,
the coupling member halves may be formed by injection molding a s~itable ;
rigid plastics material, particularly in those instances whel e electrical
continllity between the respective pipes ~ ould be disadvantageous. ,
Each coupling member half includes bolting pads 16 formed
integrally therewith, the bolting pads 16 having apertures for the reception
of bolts 1~. The bolts 17 are received within nuts 18, and act to sec~lre
the respective clamping member halves to each other in clamping
engagement with the exterior surface of the respective pipes 11 and 12. In
a preferred construction, the shanks of the bolts are other than of circular
transverse cross-section, and, are received within correspondinglv shaped
apertures in the bolting pads 16 for the bolts to be held against rotation
within the lugs. In this rnanner, the requirement for two independent
wrenches for torquing the bolts is removed, only on such wrenC}l heing
necessaly. Optionally, the bolts may be coach bolts having a neck portion
which is rectangular in transverse cross-section, or, the neck portion can
be formed of oval or other non--circlllar transverse cross-section.
Each coupling member half includes a central groove 20 within
which is received a sealing gasket 21. The gMsket may be formed of any
suitable elastomeric material, and, may be of any desired configuration in
transverse cross-section, as is ~ell known in the art. The gasket 21 is
contailled within a retainer 22 of split or segnlented construction, the
retainer 22 or the respective segments thereof being located for them to
bridge any gnp ~ hich may be present between the respective pairs of bolting
pads 16, 16. The retainer 22 has a transverse cross-section complimentary
to the outer peripheral contour of the gasket 21 and the contour of the
groove 20, and is formed from a substMntially rigid but flexible rnaterial
such as stain]ess steel or carbon steel, or, where opernting conditions permit,
a stiff but flexible p]astics material. ()ptionallv, the gasket r etainers 22
may be of foreshortened dimensions moulded integrally ~ith the gasket and
flush with the outer surface of the gasket, two o' these being di~metrically
opposed, this prc)viding the beneîit of a unitary sub-assembly and greater
convenience in nssembly.
Adjacent each axial end of the collpling member ihalves, the ;
couplill(J member halves are formed ~ith an int*rnal groove 24 for the
reception of arcuate projections 2~ forrned in the res?ective pipes ll and
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12, and which extend radially outwardly of the respective pipes and are
spaced circumferentially about the periphery thereof. The projections 25,
in conjunction with the grooves 24 in tlle nssernbled coup]in~, prevent
separation of the pipes under the flction of end pull forces and limit axial Y
movement of the pipes with respect to each other. i
The construction so far described finds counterpar t in U.S. b`
Patent No. 2,041,132 referred to above, and does not constitute the focal
point of the present invention. c
Referrinrr now more particularly to Figures 3 and 4, which
illustrates the coup1ing of the present invention applied to a pipe having ;
maximum permissible wall thickness, it will be noted that the radius of
the interior bore of each coupling member half is identical with the raclius
of the outer surface of the pipe, such that, thro-lghout its entire arcuate .
extent, the inner periphery of the coupling member is in engagement with .
the outer surface of the pipe, each of the projections 25 being fully received ,,,
within its associated groove 24. In this condition, as more clearly illllstratedin Figures 3 and 4, the end faces 16a of the respective bolting pads 16 of
the respective coupling member halves are spaced from each other, the ~
gaps between the respective pairs of end fnces 16a, which have bcen shown .
exaggerated in the drawings, being bridged by the gasket 21 and the gflsliet
retainer 2~. Even in the event thnt the bolts 17 are torqued fully in order
to place the gasket under the required compressive force, extrusion of the
gasket through the gaps between end faces 16a is inhibited by the gasket
retainer 22, which ncts to distribute the compressive forces actin~ on the
sealing gasket 21 e~ufllly throughout the entire circumierence thereof. ;
As is clearl~1 illustrated in Figures 3 and 4, the end faces 16a
of the respective pairs of bolting pads 16 of the respective coupling member
halves are coplan~r, the plane of the respective pairs of end faces 1~a
being indicated by the chain-dotted lines A1 and ~2.
In Figures 3 and 4, which illustrate the coupling of the present
invention as applied to a pipe of ma iimum wall thickness within a determined
rn~CJe of thic~inesses, each of the coupling membei halves 14 is in continuous
engagemerlt at its inner peripherv with the outer peripheral wall of the
associate pipes. Under these corlditions, ecqch of the arcuate projections 25
is fully r-eceived within its nssociated groove 2~, such that maximum restraint
is imposed on movement of the respective pipes axia11v relatively to e~qc'l
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other, or, angularly relatively to each other. FIII ther~ in view of the
continuous engagement of the inner periphery of the coupling members with
the outer wall of the pipe, distortion of the pipe from its truly circulflr
condition does not occur.
Continuous engagement of the inner periphery of the coup]ing
member halves with the outer wall of the pipe is ensured by arr anKir,g for
the radius R of the inner periphery of the clamping member halves to be
iàentical with the radius of the outer periphery of pipes having maxirnum
wall tllickness, the radius of the inner periphery of the respective coupling
member halves and that of the outer wall of the tube being taken from a
common longitudinal axis of generation indicated at B. It will be noted
that the longituAinal axis of generation B is located intermediate and Inid
way between the planes A1 and A2 of the end faces 16a of the bolting
pads 16.
Referring now to Figures 5A, 5B and 6, which illustrate the
coupling of the present invcntion when used in association with pipes having
a minimum wall thickness, it is firstly to be observed that the coupling
member halves 14, the gaslcet 21 and the gasket retainer 22 are identical
in all respects with and are in fact the same as those employed in the
embodiment of Figures 3 and 4, the sole difference in Figures SA, SB and
6 being ~that the pipes to be connected are of lesser wall thickness than
the ones illustrated in Figures 3 and 4, the internal diameter of the pipes
being identical.
Referr;ng more particularly to Figure 5A, which shows the
assembly prior to the application of torque to the bolts, the respective
coupling member halves rest on the outer wall of the pipe, which at that
time is truly circular in transverse cross-section, contact between the inner
periphery of the collpling mernbers 14 and the respective pipes occuring at
positions interrnediate and substantially mid-way between the respective
ends of the coupling members. Under these conditions, flnd having regard
to the lesser outside diameter of the pipe, the arcuate projections 25 do
not engage fully within the respective grooves 24, and, the respective
members only engage the respective pipes in line engagement.
If, as in a conventional quick-connect coupling, the end faces
16a of the bolt;ng pads 16 ~, ere at this time in face enagement with each
other, then, two entirely disadvantageous conditions arise. Firstly, restraint
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on relative axial or angular movement of the pipes is reduced or impaired
owing to the incomplete engagement of the arcuate projections within their
f~ssociated grooves, and secondly, there is a crescent-shaped gap indicated
at C between the outer periphery of the pipes and the respective cou?ling
'member halves, which will resnlt ;n incomplete seating of the inner periphery
of the coupling member halves on the outer periphery of the pipe, and,
will resu]t in the compressive stress exerted on the gasket member being
of progressively decreasing intensity from the mid-point of the respective
coupling members towards the ends thereof. This will or can result in ,
incomplete sealing of the pipes by the coupling, with consequential seepage
axially of the outer periphery of the pipe, and, in the case where split
gaskets are employed, also can result in seepage at the radial interface of 5-
the respective gasket members. ~'
These problerns are obviated in their entirety according to the Ir
present application, by arranging for the end faces 16a of the respective
bolting pads 16 to be spaced from each other prior to and during torquing
of the bolts, with the results which will now be discllssed with reference
to I~igur e SB.
Upon torquing of the bolts, the respective coupling member
halves, which already are in line engagelnent with the outer surface of the
pipe at a point mid~'way between their ends, will exert a radially inward
force on the pipes at those positions, and will stress the pipes causing'them
to deform from a truly circular transverse cross-section to a transverse
cross-section which is substantially elliptical, the major axis of the ellipse
lying in a plane coincident ~vith or parallel to the respective planes A1 and
~2 of the ends faces of 16a ot` the respective bolting pads.
In distorting or deforming to sustantially elliptical
configuration, the radius R1 along the major axis of the ellipse wiU
progressively increase, and, the radius R2 along the minor axis will
pro~ressively decrease, thus forcing the entire outer periphery of the pipes
into intimate seating engagemellt witll the inner periphery of the coupling .
members 14, and~ thus forcing the arcuate pr~jections 25 into full seating
engagement within their associated grooves 24. Further, as the bolts are
progressively torqued the pipes will progressively qssume a shape in ~hich
they are in continuous engagement wit]l the gas!~et, and, in which the ~i
compressive stresses in the gasl;et are equalized throughout the entire ~
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circumference thereof. In this w~y, the problem of seepage either axially
of the outer periphery of the pipes, or rad;ally through the interface of
the gasket members where a split gasket is employed, is elirninated in its
entirety.
It ~ill be appreciated that in finally assembled condition of
the coupling, the transverse cross-section of the respective pipes wil~ deviate
slightly from an elliptical condition, the cross-section being theoretically
that of two overlapping semicircular segments which intersect eacn other
at the plane of the respective bolting pads, which, at that time are coincident
with the centroid B of the pipes. The original longitudinal axis o~^ generation
B of the respective coupling member halves now lie above and below the
centre of the pipes as shown in Figure 6.
~ or pipes of a wall thickness intermediate the minimal wall
thickness illustrated in Figures 5A, 5B and 6 and the maximum wall thickness
illustrated in Figures 3 and 4, continuous engagement of the outer sllrface
of the pipes with both the coupling member halves and the gasket member
will occur and full seating and sealing will;be obtalned, the sole difference ~:
being that, with a progressive increase in wall thickness of the pipes, a
pro"ressively increasing gap will occur between the respectiYe pairs of end
faces 16A of the bolting pads 16.
The advantages accruing from ;the present invention stem from
determined dimensional relationships bet~veen the coupling members and the
range of wall thickness of the pipes to be accommodated by said coupllng
members.
As will be~ readily apparent, in order to obtnin continuous
seating of the coupling member halves relati~rely to a pipe having maximum
wall thickness, then, the radius of the inner periphery of the respective .
coupling members must be identical with the `radius of the outer surface ~r
of the periphery of the pipe.
If one assumes a range of pipes having the same internal .
diameter D, and having a minimum thickness T1 and a maximum thickness i~
T2, then, the radius R of the inner periphery of the respective coupling ~?-
member halves must be D +22 ~T2)
~ n the other hand, in order to accommodate pipes of a wall
thickness at the minimum end of the range, the combined lengths of the
inner periphery of the coupling member halves must not be more than the
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length of the circumference of the outer surface of such pipes of minimum
wall thickness. This relationship can be expressed as ~ (D ~ 2T1) .
This relationship is critical, in that if the combined lengths
of the inner peripheral walls of the coupling members is greflter than the
'length of the circumference of the exterior surface of a pipe minimum
wall thickness, then, the end faces 16a will engage each other prematurely
and prevent further elliptical deformation of the pipe prior to reachinb the
required seating and sealing of the external periphery of the pipe relatively
to the clamping members and the gasket.
While there has been described a coupling comprised by
coupling member halves, it will be fuliy appreciated that for certain
applications the' coupling members could be comprised by more than two f-
coupling members, for example, three coupling members with the bolting
pads arranged in Y arrangement. Provided that each such coupling rnernber
is formed with its inner periphery of a radius identical with the radius of i
the outer surface of a pipe of ma~cimum wall thickness, and, provided that
the combined len~ths of the inner periphery of the respective coupling
members does not exceed the circumfercntial length of the outside surface
of a pipe of mininum wall thickness, then, exactly the same desirable
conditions will be obtained as those discussed above with respect to a
two-part coupling. The only difference will be that the cross-section of ~
the tube will be deformed or displaced into three segments instead of two, ~c'
each of which will seat fully on the inner periphery of the assembled
coupling, with full engagement of the arcuate projections ~5 within the
grooves 24, full engagernent of the respective coupling members with the
outer periphery of the pipes, and, full seating of the contained gasket
mernber with the outer periphery of the pipes and equalization of the
compressive stresses e~erted on the gasket member.
It will be appreciated that the structures illustrated in the `
drawings are by way of example only, and, that various modifications may
be made within the scope of the invention as defined by the appended claims.
ln par~iculflr, while the invention has been described in
relationship to thin-walled pipes which have been provided with radially
outwardly extending arc~late projections, the coupling could also be used
Witil plain' ended pipes devoid of such arcuate projections in those situations -
where relative axial movement between the pipes cannot occur Optionally,
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elamping ja~Ys having ineisor teeth eould be ineorporated into the grooves
of the coupling members, or, the coupling members themselves eould be
formed with incisor teeth to provide nn fldditional grip on plain-ended pipes.
Alternatively, the pipes could be inwardly dimpled at cireumferentially
spaced positions and tile eoupling rnembers provided with corresponding dogs
or teeth for entry into sueh dimples, the major consideration being that
the formation of the pipes ~ith either arcuate radially outwardly extending
projections or arcuAte radially inwarding extending dimples shall not
interîere materially with the eapability of the pipes to distort or deform
from their truly eireular eondition to a eondition of plural or multiple
segments each having an outer radius whieh is that of the radius of the
outer surface of a pipe having maximum wall thiekness.
Further, while the invention has been described with reference
to a double-ended coupling for conneeting the adjacent ends of a pair of
pipes to each other, the invention has equal applieation in a flanged, single-
ended coupling employed for conneeting a pipe end to an adjacent structure.
Figure 7 illustrates such a flan~ed coupling, the coupling
ineorporating all of the design parameters set out above with respect to
the coupling of Figures I through 6, the major differences being in the
adaptation of the coupling of Figures 1 through 6 to the form of a flanged
coupling.
In Figure 7, the eoupling member, indicated generally at 30,
is shown applied to the end of a pipe 31 having spaced radially extending
arcuate projections 32 adjacent the free end thereof.
In an identical manner to that described above Yith reference
to the coupling of Figures 1 through 6, the flanged eoupling 30 of Figure
7 ineludes coupling member halves 33 and 34 having radially extending
bolting pads 35 and 36, which are secured to each other by bolts 37 and
torqueing nuts 38, as previously described, in clamping engagement with
the exterior surface of the pipe 31.
Each of the coupling member halves 33 and 3-1 includes a
groove 39 for the reception of radially extending arcuate projections 32
formed adjflcent the end of the pipe 31, again, in the same manner as that
discussed above with r espeet to Figures 1 through 6, and, each of the
coupling mem~cr hnlves 33 and 34 includes a recess 4~ in which is received
a gas~et mernber 41 ~hich is formed from any suitable elastomeric mate, ial.
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The respective coupling member halves each include a radially
extending flange 42 having bolt holes 43 at circumferentially spaced !~
positions, whereby the flanges may be attached to an adjacent structllre
having a planar face, or, whereby the flanges may be attached to the
flanges of a similar or identical coupling attached to the end of another
pipe, the said other pipe either being identical in dimensions with the pipe
31, or1 differing therefrom in respect of its internal radius or wall thickness. .
Conveniently, and as illustrated, the bolting pads 35 are
provided with a rectangular key 35A which is received ~rithin a rectangular ~
keyway 36a in the bolting pads 36. The provisions of the key and keyway ':r
acts to stabilize the respective coupling member halves on the end of the
pipe during the assembly of the coupling onto the pipe end, and, further
acts to ensure that the planar end faces of the coupling mernber halves
are brought into co-planar relatio1lship with each other prior to the ~langes
being at tached to the said adjacent structure.
In order not to interfere with the design parameters of the
coupling, the keys 35a nre of a height no greater than the depth of the
keyways 36a, the keys 35a preferably being of lesser height than the depth ,
of the keyways 36a. Additionally, the bolt holes 43 either are formed
oversized in relationship to the bolts which extend therethrough, or, they
are for~ed elongate in a direction radially of the longitudinal axis o~ the
pipe and coupling. In this way, radially outward or radially inward
movernents of the coupling member halves which are required in order to
accomodate pipes of different wall thicl<ness can be accomodated without
the necessity of repositioning the bolt holes in the structure to ~hich the
cou?ling and pipe is to be attached.
Referring now to Figure 8, which illustrates in greater detail
the gasket employed in the embodiment of Figure 7, the gasket includes a
generally axially extending lip seal 41a for engagement with the outer
periphery of the pipe, and includes a generally r adially extending lip seal ;
41b for sealing engagernent t^~ith the said adjacerlt structure to which the
coupling is attached. r~
Conveniently, and as illustrated in Figure 8, instead of being r~
contained within a substantially continuous retainer or extrusion shield as
described with reference to Figures 1 through 6, e~trusion shields ~4 are
provided as an integral part of the gasket 41J the extrusion shields 44 being
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placed in 1I mold prior to the molding of the gasket, and thus being locsted
in situ in the finished gasket. The provision of the extrusion shields 44 as
an integral part of the gasket greAtly facilitates hnndl}ng of the gasket at
the point of assembly at the coupling, and, eliminates the requirement for
a separate extrusion shield or retainer. In use, the gasket is placed on
the end oî the pipe, and, is then rotated to a position at which it will span
the adjacent ends of the respective coupling member halves, subsequent to
which the bolts are torqued down to fully assemble the coupling onto the
pipe end.
Referring now to Figure 9, the same modification as is
discussed above with respect to Figure 8 is shown as applied to the sealing
gasket 21 of Figures 1 through 6. In Figure 9, respective segments 22a of
the retainer are located at diametrically opposed positions within the mold
employed for forming the sealing gasket 21, and thus become an integral
part of the gasket during the molding process.
Preferably, the respective retainer segments 22a and 44 are
either formed for them to be reflective, or, are formed or otherwise colored
for them to be clearly distinguishable from the body of the sealing gasket
21. By so doing, the positlon of the retainers easily can be observed by
an operative assembly the coupling, who will be given a visual indication
that the retainers are correctly positioned relatively to the adjacent faces
~ .~
of the resRective pairs of bolting pads, in the manner indicated in chain- ;
dotted lines in Figure 7.
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A
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