Note: Descriptions are shown in the official language in which they were submitted.
: l ~ s
RETAINER GLAND FOR MECHANICAL JOINT PIPE
BACKGROUND O~ THE INVENTION
1. Technical Field.
This invention relates to restrained connections for
flexible joint pipe and particularly to a restrained connection
for mechanical joint pipe.
2. Background Art
. _
Gray iron and ductile iron pipes in nominal sizes
ranging from 2 inches to 48 inches are extensively used in
systems handling water and other liquids at pressure ratings
rom 150 to 350 pounds per square inch. Conventional connections
for such pipes are of three general types: bell~and-spigot
(or slipwon), flanged, and mechanical joint.
A bell-and-spigot connection is the simpl~st and least
expensive; it is made up by inserting a plain end of one pipe
into a bell end of another pipe or fitting. The joint is
traditionally sealed by lead calking, but in recent years rubber
gaskets have become more popular.
In a flanged connection, each end of a pipe or fitting
has an integra]ly cast or a threaded on flat-faced flanye, and
the joint is made up by bolting together the flanges of two
abutting pipes, or a pipe and a fitting, with a flat rubber
gasket between the flange faces.
A mechanical joint is a bolted joint of the stuffing
box type and comprises three elements - a flanged bell, a
rubber sealing gasket, and a compression ring or gland. The
bell may be cast as an integral part of one end of a ~tandard
length of pipe or a fitting (e.g., a tee, elbow, etc.), or it
may be cast as a separate unit and threaded for assembly onto a
threaded end o a pipe, in the same manner as a threaded flange~
The bell end of one pipe section accepts a plain end of another
pipe section of the same nominal size, after ~irst slipping a
flanged gland and a rubber ~asket over the plain end. The
gasket fits inside the bell and is maintained in compression by
bolting the flange of the gland to the flange of the bell.
A principal advantage of bolted flange connections
is that the bolts prevent axial separation of the joint; however,
such a connection will not accommodate any angular misalignment.
Both bell-and-spigot and mechanical joint connections, on the
contrary, can tolerate varying degrees of angular misalignment,
depending on the pipe diameter, but friction of the gasket
provides the only restraint against separation of the joint.
Although the compression exerted by the gland of a mechanical
joint connection increases the frictional resistance, as well as
improving the sealing effectiveness, of this type of joint as
compared with a rubber-gasketed bell-and-spigot connection,
massive concrete foundations or other restraining means are
required to pxevent separation by internal pressure at locations
where a pipeline changes direction.
Vaxious types of locking devices are available~ for
restraining slip-on or mechanical joint connections r but these
2.
devices either convert the joint into a rigid connection,
thereby losing the angular flexibility which is the principal
advantage of such connections, or the devices require a
substantial amount of precision machining, which greatly
increases their cost.
Examples of loclcing devices are shown in the American
Pipe Manual, Fifteenth Edition, 1979, published by ~merican
Cast Iron Pipe Company, Birmingham, Alabama, and include
retainer rings welded to the outside of a plain end pipe to
prevent the pipe from slipping through a gland ring bolted to a
flanged mating bell end pipe or fitting tpages 9-2 to 9-6),
setscrews threaded radially through a mechanical joint gland
into the outside of plain end pipe (pages 9 10 to 9-12), and
setscrews through a plain end pipe from inside and engaging a
groove machined inside a mating slip on bell (pages 9~15 to
9-16). Double-ended adapter glands are also available, for
mating assembly between opposed bell ends of mechanical joint pipe
(page 9-7. See also Clow Corporation catalog "Pipe Economy,"
published 1975, at pages 85-9~. These restraining devices
permit pipe to be laid with initial angular deflections, but do
not accommodate subsequent de1ections due to settling after
installation. To retain flexibility after assembly, it is
necessary to use ball joint pipe (pages 10-1 to 10-21 of
American catalog or pages 55-59 of Clow catalog). Ball joint
pipe is expensive, however, because the surfaces of the ball
and mating socket must be accurately machined.
SU~MARY OF THE INVENTION
It is a principal object of the present invention,
therefore, to provide a flexible restrained mechanical joint
connection which not only permits angular misalignment at the
time of initial assembly but also accommodates movement of the
joint after assembly due to set:tling.
Another object of the invention i~ to pxovide a
restrained mechanical ~Oillt conllection which is inexpensive
to manufacture and easy to assemble in the field.
Still another object of the invention is to provide
a restrained mechanical joint connection which does not require
modification of either plain end or the bell end of the pipes
or fittings being joined.
Another ob~ect of the invention is to provide a
restrained mechanical joint connection which has a minimum
number of parts in addition to those required for a standard
mechanical joint connection~
Th~se and other objects are achieved by use of a
retainer gland for mechanical joint pipe and mechanical joint
fittings, the glandincl~ a flat ring portion having two
substantially parallel faces and a circular inner circumference,
and a circular rib portion extending generally axially from one
face of the flat ring portion adjacent said inner circumference,
the flat ring portion and the cirrular rib portion having a
generally L shaped radial cross section, wherein the retainer
gland further comprises at least a first hinge arm extending
generally axi,ally from the other faee of ~he 1at ring portion
and terminating in an outer end portion, the hinge arm having a
transverse hole ~hrough said outer end portion.
Prefera~ly, the transverse hole through the outer end
portion of the hinge arm has a longitudinal axis which is sub-
stantially perpendicular to a diarnetral plane of the flat ring
portion, and said first hinge arm is located on one side of and
closely adjacent to said diametral plane. In addition, the
retainer gland preferably further comprises a second hinge arm
substantially congruent with said first hinge arm and having a
transverse hole coaxial with the transverse hole .in the first
hinge arm, said second hinge arm extending from said other face
of the flat ring portion in spaced relation to the first hinge
arm on the other side of said diametral plane, the spacing
between the first and second hinge arms being slightly greater
than the transverse thickness of the first hinge arm, and a third
hinge arm substantially congruent with the first and second
hinge arms and having a transverse hole coaxial with the trans-
verse holes in the first and second hinge arms, said third
hinge arm extending from said other face of the flat ring portion
in spaced relation to the first hinge arm and on the same side
of said di~metral plane, the spacing between the first and
third hinge arms beins slightly greater than the transverse
~hickness of the second hinge arm, and said transverse holes in
the first, second, and third hinge arms being elongated in a
dixection substantially perpendicular to the faces of the flat
ring portion.
The restrained mechanical joint connection of the
inventio~ comprises an assembly of a first retainer gland, as
5.
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defined above, and a second retainer gland substantially
identical to the first gland. The second retainer gland is
arranged with its flat ring portion substantially coaxial with
andspaced fxom the flat ring portion of the first gland member
and with its first hinge arm in lapped abutment with the first
hinge arm of the first gland member, and a hinge holt extends
through the txansverse holes in the hinge arms of the fixst and
second gland members.
The retainer gland assembly is adapted to be installed
on a spacer pipe having plain ends which are inserted into
mating mechanical joint bell ends of adjacent pipes and/or
fittings, the flat ring portion of each retainer gland being
clamped to the respective mechanical joint bell by flange bolts
in the conventional manner to compress a rubber gasket encircling
the spacer pipe inside the bellO
These and other features and advantages of the invention
are discussed in detail in the following description of the
preferred embodiment, as shown in the accompanying drawings.
BRI~I n~sCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a restrained mechanical
joint connection assembly applied to adjacent ends of two pipes
in tandem.
FIG. 2 is a plan view, partly in section, of the
restrained mechanical joint connection of FIG. 1.
FIGS 3 to 6 are elevation views in section of successive
stages in the assembly of a restrained mechanical joint connection
according to tlle invention.
i7.~
DETAILED DES~IPTION 0~ T~E P:E?EFERRED EMBODIMENT
FXGS. 1 and 2 show a restrai.ned mechanical joint pipe
connection which incorporates a retainer gland assembly 10
according to the preæent invention, the gland assembly comprising
a first retainer gland 11 and a second retainer gland 12 coupled
together by a hinge bolt 13 and associated nut 14 and washers
15 and 16.
~ he irst;retainer gland 11 has a flat ri~g portion 17
with two substantia.lly parallel faces 18 and 19 and a circular
inner circumfexence 20. A circular rib portion 21 extends
generally axially from the face 18 adjacent the inner circum-
ference of the ring r and firstl second, and third h.inge arms
22, 23, and 24, res~ectively, extend in spaced apart relation
generally axially from the other face 19 of the flat ring portion.
The hinge arms terminate in outer end portions 25, 26, and 27
through which extend transverse holes 28, 29, and 30~ respectively,
for accommodating the hinge bolt 130 These transverse holes
are elongated in the axial direction (see FIG, 6) to provide a
substantial amount of play for the hinge bolt in that direction.
As is apparent from FIG. 2l a longitudinal axis of
each hinge arm is substantially perpendicular to each face
of the flat xing portion 17l and the first hinge arm 22 is
located on one side of and closely adjacent to a vertical plane
(denoted by dash dot line 31) which diametrally intersects
the flat ring portion o~ the first xetainer gland. Also
apparent from FIG. 2 is the fact that the spacing between the
first hinge arm 22 and the second hinge arm 23 is slightly
greater than the transverse thickness of the first arm, and
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that the ~pacing between the first arm and the third arm 24 is
slightly greater than the transverse thickness of the second
hinge arm 23.
This offset arrangement and spacing of the hinge
arms permit~ ~he use of essentially identical units for the
first and second retainer glands The second retainer gland
12 also has a flat ring portion 32 with parallel faces 33 and
34 and a circular inner circum~erence 35 (see FIGS. 4 - 6).
A circular rib portion 36 extends from one face 33, and first,
second, and third hinge arms 37, 38, and 39, respectively,
extend ~rom the other face 34 to terminate in outer portions
40, 41, and 42 having respective elongated tr.ansverse holes 43,
44, and 45. Thus, the first hinge arm 37 of the second retainer
gland laps the first hinge arm 22 of the first retaine~ gland
and is able to slide loosely between the first and second hinge
arms of the first gland. Similarly, the second hinge arm 38
of the second gland is able to slide loosely between the first
and third hinge arms of the first retainer gland, and the
hinge bolt 13 passes loosely thxough the transverse holes of
all of the hinge arms.
The above-described retainer gland assembly forms a
restrained mechanical joint connection when incorporated with a
spacer pipe 46 inserted into mechanical joint bell ends 47 and 48
of pipes or fittings 49 and 50, xespectively, and flat ring
portions 17 and 32 are clamped by means of T-head bol~s 51 and
52 and nuts 53 and 54 to the xespective 1anges 55 and 56 of
the mechanical joint bells 47 and 48.
FIGS. 3 to 6 illustrate progressive stages of assembly
for the restrained mechanical joint connection. In FIG. 3, a
rubber mechanical ring gasket 57 of standard design is placed on
one end 58 of spacer pipe 46, and that end is then slipped
into the mouth of mechanical joint bell 48. One retainer gland
12 of the pair of identical gl,ands 11 and 12 is then slipped
over the other end 59 of the s;pacer pipe with the circular rib
36 facing the gasket 57, T-bolts 52 are inserted through
matiny holes in flange 56 and flat ring portion 22, and the
gland rib is drawn up to compress the gasket against the spacer
pipe and the inside of the bell by screwing nuts S4 onto the
threaded ends of bolts 52.
Next, the other retainer gland 11 of the pair i5
slipped over end 59 of the spacer pipe, with its circular rib 21
facing in the oppsoite direction from that of gland 12 and with
its hinge arms overlapping the hinge arms of retainer gland 11,
as shown in FIGo 4~
The bell end 47 of the next pipe or fitting 49 is
then slipped onto end 59 of spacer pipe 46, aftex first placing
a second gasket 60 on the spacer pipe, as shown in FIG. 5. Gland
12 is then slid back into contact with gasket 60 and bolted
to its mechanical bell in the same manner as gland 12~ As shown
in FIG~ 6, the length of spacer pipe 46 is such tha~ when the
two glands are bolted to their respective mechanical joint
bells, the transvers~ holes in the outer end portions o~ ~heir
respective hinge arms are in general alignment so that hinge
bolt 13 can be inserted to complete the assembly of the
restrained mechanical joint connection~
~,
It will be apparent from FIG. 6 and FIG. 2 that the
assembled mechanical joint connection of the present invention
permits angular misalignment o~ the spacer pipe with each mechanical
joint bell to the design limits o~ the bells, not only in a
vertical plane (by reason o~ pivoting of the hinge arms about
the hinge bolt axis) but also in a horizontal plane (by reason
of the play provided by the elongation of the transverse holes
in the hinge arms and their tapered contact faces, shown
particularly in FIG. 2).
~ s a result o~ the "hinge" palcement on one side of
the pipeline axis (preferably on top for easiest access) a
restrained mechanical joint connection is provided which
maintains full flexibility to accommodate settling subsequent
to installation of the piping system.
The above-described design is readily applicable to
any standard size of mechanical joint pipe, from 2-inch to 54-inch,
and the retainer gland~ are easily and simply manufactured by
adding hinge arms to standard patterns for conventional mechanical
joint glands. All of the other components of the assembly
are standard readily available mechanical joint fittings and
accessories. Consequently, the invention solves simply and
economically a long-standing problem in the art of mechanical
joint piping.
