Corporation stop assembly

A corporation stop has a threaded stem with an enlarged, conical head portion and a neck portion of reduced size coaxially surrounded by a resilient sleeve member. A flat, annular compression ring rests above the sleeve member and has at least one notch formed radially in its outer edge and has on its lower side a sleeve receiving recess of a diameter greater than that of the annular opening to receive the upper end of the sleeve member. A clamp nut is engageable with the neck portion of the threaded stem. A saddle member having at least one tab projecting radially engages the notch in the compression ring. As the clamp nut is engaged with the neck portion of the threaded stem, the compression ring is forced against the resilient sleeve member so as (1) to forcibly move the upper end of the sleeve member within the compression ring recess to form an external seal between the compression ring and the external sidewall of the conduit, and (2) to forcibly move the lower end of the sleeve member over the conical head portion to thereby expand the lower end of the sleeve member and form an internal seal with the opening in the lined conduit.

BACKGROUND OF THE INVENTION 
The invention relates to a corporation stop of the type adapted to be 
installed in the sidewall of a fluid bearing conduit to form a junction or 
branch and, specifically, to such a stop that is adapted for installation 
within a lined conduit using standard drilling and tapping machines. 
A variety of circumstances exist in which it is desirable to form a 
junction or branch line from a main, fluid carrying conduit. For instance, 
in the municipal area, it is often necessary to install a branch line into 
a water main, gas main or sewer main. A similar need exists in other 
industries, such as in the chemical pipeline industries. 
In the municipal area, many water mains were constructed years ago and the 
wall structures are now badly eroded or collapsing. In order to repair 
such damage, it has been proposed to insert a liner within these lines to 
provide a new water-impervious wall to the system. There are various 
different methods available in the industry for inserting synthetic liners 
within existing conduits, such as the cured-in-place, fold-and-form and 
diameter reduction methods, each of which inserts a liner from one end of 
the conduit to the other. However, the wall of the line is usually not 
continuous since branch lines intersect the main conduit at various entry 
ports to allow the free flow of fluid from the main to the branch line. In 
the case of existing and newly formed entry ports, it is desirable to 
utilize a corporation stop at the junction to control the fluid on either 
a temporary or permanent basis. 
Although a variety of corporation stops are known in the prior art, all 
suffer from various deficiencies. Many of the prior art assemblies are 
complicated in design and are time consuming to install. In many cases, it 
was not possible to install the stop on a "live" line that was carrying 
fluid under pressure. Although standardized machinery has been developed 
for installing corporation stops in conduits carrying fluid under 
pressure, such as the B-101 drilling and tapping machines manufactured by 
Mueller Co., this machinery is not well suited for use with a conduit that 
has been lined or rehabilitation with a synthetic liner. 
The prior art corporation stop assembly that is specifically designed for 
installation in a conduit that is lined with a synthetic liner is 
disclosed in U.S. Pat. No. 5,199,145 (McMillan et al.). The corporation 
stop assembly disclosed therein has a flexible sleeve member and a 
threaded stem with an enlarged head portion, and is installed into the 
lined conduit by way of a clamp nut that engages the neck portion of the 
threaded stem for forcibly moving the lower end of the sleeve member over 
the head portion of the stem to expand the lower end of the sleeve member 
and form an internal seal with an opening in the conduit. The McMillan 
patent also discloses a specific apparatus to be used for installing that 
corporation stop in a live, pre-lined conduit carrying fluid under 
pressure. 
While this corporation stop is effective for use in lined conduits carrying 
therein fluid under pressure, the apparatus shown in the McMillan patent 
for installing the corporation stop in a lined conduit is fairly large and 
unwieldy and may not be suitable for situations in which the space 
available along the conduit adjacent the spot for installation of the 
corporation stop is less than the amount of space physically required by 
the disclosed installation apparatus. Furthermore, the McMillan patent 
shows no way in which the corporation stop disclosed therein can be 
installed using standard drilling and tapping equipment, such as the 
Mueller B-101 machine for drilling, tapping and installing corporation 
stops in unlined conduits, and others manufactured by ALH and Wask, which 
are well known to those skilled in the art. 
SUMMARY OF THE INVENTION 
Generally speaking, in accordance with the invention, a corporation stop 
for use with standard drilling and tapping machinery is provided for blind 
side sealing of an opening that is made in an external sidewall of a 
longitudinally extending conduit of the type lined with a synthetic liner 
also having a concentric opening. The corporation stop has a threaded stem 
with an enlarged, conical head portion and a neck portion of reduced size. 
A resilient sleeve member coaxially surrounds the neck portion of the stem 
and has an upper end and a lower end that is adapted to accommodate the 
enlarged, conical head of the threaded stem. A flat, annular compression 
ring, whose opening is aligned with the opening provided through the 
sidewall of the conduit and the liner, rests above the sleeve member and 
has at least one notch formed radially in its outer edge. The lower side 
of the compression ring has a sleeve receiving recess of a diameter 
greater than that of the annular opening, the diameter of said recess 
being selectively sized to receive the upper end of the resilient sleeve 
member. The corporation stop also has a clamp nut that is engageable with 
the neck portion of the threaded stem. A saddle member for stabilizing the 
standard drilling and tapping machine is placed on the external sidewall 
of the conduit about the opening. The saddle member has an annular opening 
shaped to receive the compression ring within it and the inner edge of the 
opening has at least one tab projecting radially and shaped to engage the 
notch in the compression ring. 
To install the corporation stop, the clamp nut is first engaged with the 
neck portion of the threaded stem. This forces the compression ring 
against the resilient sleeve member so as (1) to forcibly move the upper 
end of the resilient sleeve member within the sleeve receiving recess of 
the compression ring to form an external seal between the compression ring 
and the external sidewall of the conduit, and (2) to forcibly move the 
lower end of the resilient sleeve member over the enlarged, conical head 
portion of the threaded stem to thereby expand the lower end of the sleeve 
member and form an internal seal with the opening in the lined conduit. 
Accordingly, it is desirable to provide an improved corporation stop which 
overcomes the shortcomings of the prior art and is easily installed with 
conventional tapping equipment. It is an object of the invention to 
provide a corporation stop for a pre-lined fluid-carrying conduit which 
allows blind side installation by cutting a hole straight through the 
conduit from the exterior. 
Another object of the invention is to provide such a stop which seals on 
both the interior and exterior sidewalls of the fluid-carrying conduit. 
Still another object of the invention is to provide a stop which more 
securely engages a previously installed synthetic liner within a conduit 
to eliminate any annular gaps which might be present between the liner and 
host conduit. 
Yet another object of the invention is to provide a sealing element for the 
corporation stop which is linearly and radially reinforced to resist shear 
forces during installation and reduce the chances of a blowout during the 
operational lie of the stop. 
A further object of the invention is to provide a corporation stop for a 
pre-lined conduit carrying fluid under pressure utilizing standard 
drilling and tapping equipment. 
Yet a further object of the invention is to provide a method of 
installation of the corporation stop. 
Still other objects and advantages of the invention will in part be obvious 
and will in part be apparent from the specification. 
The invention accordingly comprises the several steps and the relation of 
one or more of such steps with respect to each of the others, and the 
apparatus embodying features of construction, combination(s) of elements 
and arrangement of parts which are adapted to effect such steps, all as 
exemplified in the following detailed disclosure, and the scope of the 
invention will be indicated in the claims.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 shows a corporation stop constructed and arranged in accordance with 
the invention, designated generally as 11, installed on a longitudinally 
extending host conduit 13. Host conduit or pipe 13 could be, for instance, 
a water main, gas main, sewer pipe, or the like. In this case, pipe 13 is 
of steel and has a generally cylindrical interior sidewall 15 which has 
been lined with a synthetic liner 17 formed from a cured in place liner or 
polyolefin, e.g. polyethylene. 
A well-known process for rehabilitation of existing conduits generally 
utilizing a flexible liner to be cured in place is the "Insituform.RTM." 
method described in U.S. Pat. Nos. 4,009,063 and 4,064,211, the contents 
of which are incorporated herein by reference. Another rehabilitation 
process known as the NuPipe.RTM." process described in U.S. Pat. Nos. 
4,867,921 and 5,255,624, the contents of which are incorporated here by 
reference. In this latter process a substantially rigid replacement pipe 
is installed in a flattened and folded shape, heated and expanded to the 
shape of the original conduit. Another process for lining conduit familiar 
to those skilled in the art is diameter reduction which is described in 
issued U.S. Pat. No. 4,923,663, to McMillan. 
FIG. 2 shows corporation stop 11 in exploded fashion. Corporation stop 11 
includes a stem 19 having external threaded and optionally an internal 
thread. In sequential relation stop 11 includes an enlarged, 
conically-shaped head portion 21 and a neck portion 23 of reduced size. 
Neck portion 23 terminates in an extension portion 25 that passes through 
an outer compression ring 37 having an inner bore 43 and an outer clamp 
nut 55. 
A resilient sleeve member 27 formed of a flexible, elastomeric material is 
received about neck portion 23 of stem 19. Sleeve member 27 has an upper 
end 29 and has a lower end 31 that is adapted to accommodate enlarged head 
portion 21 of threaded stem 19 during assembly. As shown in FIGS. 3a and 
3b, sleeve member 27 can conveniently be provided as a generally 
cylindrical body 33 that can be linearly and radially reinforced, as with 
steel belting 35 shown in FIG. 3b. Steel belting 35 is encapsulated within 
the sidewalls of body 33, circumscribing internal bore 36. 
Compression member 37 has upper and lower sides 50 and 51, respectively, 
and a central opening 43 (FIGS. 2 and 4) which is alignable with opening 
45 provided in the sidewall of conduit 13. Central opening is formed with 
a keyway 71 for receiving a key 75 to prevent stem 19 from rotating during 
assembly. Lower side 51 of compression member 37 is provided with a recess 
47 for receiving upper end 29 of sleeve member 27 when stop 11 is 
installed within host conduit 13 for forming an external seal with respect 
to the conduit. The seal are is illustrated at approximately 49 in FIG. 6. 
As shown in FIG. 2, extension portion 25 of stem 29 is of lesser relative 
diameter than neck portion 23, thereby forming a step 57 with respect to 
neck portion 23. Extension portion 25 is selectively sized to matingly 
engage the iron pipe thread of a pipe coupling installed on the exterior 
of the conduit 13 during a later step in the installation. Neck portion 23 
of stem 19 is formed with a keyway 73 for receiving key 75. 
Clamp nut 55 is engageable with neck portion 23 of threaded stem 19 for 
forcibly moving lower end 31 of resilient sleeve member 27 over conical 
head portion 21 of threaded stem 19 to expand lower end 31 of sleeve 
member 27 and form an internal seal with opening 45 in lined conduit 13. 
Corporation stop 11 is, until this point, similar to that disclosed in the 
McMillan patent. However, instead of having an enlarged compression washer 
contoured to match the outside curvature of conduit 13, corporation stop 
has a modified smaller compression ring 37 (FIG. 2) that has at least one, 
but preferably two, radial notches 39 formed into outer edge 28. 
Compression ring 37 has a central opening 43 (FIGS. 2 and 5) that is 
alignable with opening 45 cut through the sidewall of conduit 13. The 
upper surface of compression ring 37 has a generally planar surface for 
receiving clamp nut 55. Compression ring 37 or the bottom surface thereof 
can be contoured to match the curvature of the external sidewall of host 
conduit 13. 
Corporation stop assembly 11 also includes a saddle 53, which is preferably 
formed of cast iron. Saddles are generally known in the art and are formed 
so that a conventional drilling and tapping machine can be held in place 
against the host conduit at a particular position on the surface pipe for 
installation of a corporation stop. Such saddles are available from 
Mueller Co. as well as from other manufacturers and are generally formed 
in flat, annular shape, having an outer diameter and an inner diameter 
(see FIG. 2). Preferably, such saddles have an inner annular rim 40 of 
intermediate height with an inner edge corresponding to that of the saddle 
and outer edge having a diameter greater than the inner diameter and less 
than the outer diameter of the saddle. Rim 40 enables easy placement of 
the drilling and tapping machine so that the machinery does not slip 
relative to pipe 13 or saddle 53 during operation. In addition, a rubber 
gasket is placed under modified saddle 53 in order to help prevent leaking 
and slippage of saddle 53 during the tapping operation. In an alternative 
embodiment an insulating washer or gasket can be positioned between 
compression ring 37 and conduit 13. This can electrically isolate the 
fitting from the host conduit. A saddle is chosen for use on a particular 
conduit such that the curvature of the bottom surface of the saddle is 
contoured to match the curvature of the external sidewall of host conduit 
13. 
A standard Mueller saddle has been modified in accordance with the 
invention to form saddle 53 with a modified inner edge 54 of opening 42. 
Inner edge 54 has at least one, but preferably two, tabs 41 that protrude 
radially into opening 42 of saddle 53. Tabs 41 are formed as part of 
saddle 53 and are most preferably dimensioned to match the dimensions of 
notches 39 that are formed in outer edge 38 of compression ring 37. 
Opening 42 of saddle 53 is dimensioned so that the inner diameter is 
slightly larger than the diameter of compression ring 37, thereby allowing 
compression ring 37 to fit within opening 42 of saddle 53. 
As discussed above, it is desirable to be able to use standard drilling and 
tapping machines for installation of corporation stop 11 into lined 
conduit 13. A Mueller B-101 drilling and tapping machine that is used with 
unlined conduits, well-known to those skilled in the art, is shown in FIG. 
4. In normal operation, a standard Mueller drilling and tapping machine, 
generally designated 61, is equipped with a sealed valve 63 that is 
chained or strapped to host conduit 113, with a saddle 65 situated between 
conduit 113 and valve 63. A drilling and tapping head 67 is attached to 
the end of a boring bar 69 for drilling a hole through conduit 113 and for 
forming threads in the inner edges of the hole. The corporation stop is 
then attached to boring bar 69 after the drilling and tapping head 67 is 
extracted and removed from boring bar 69, and screwed into the hole. 
A modified saddle 53, as discussed above, preferably with a rubber gasket 
underneath it, is placed between conduit 13 and the valve of the drilling 
and tapping machine. Also, in forming an opening in a lined conduit, a 
drilling head cannot be used, as it will tend to tear synthetic liner 17. 
Rather, a hole saw must be used so as to cut, rather than drill, a hole 45 
through both original host conduit 13 and synthetic liner 17 within. 
FIGS. 5-7 illustrate the installation of corporation stop 11 within an 
opening provided in host conduit 13. It should be noted that the 
components of stop 11 at this time are located within valve 63 of the 
Mueller drilling and tapping machine 61, which rests on annular rim 40 in 
the interior of saddle 53. FIGS. 5-7 show the installation of stop 11 and 
the movement of its components inside valve 63 after hole 45 has been cut 
through conduit 13 and liner 17 by Mueller machine 61. 
FIG. 5 illustrates the relative arrangement of the components of stop 11 
prior to installation within host conduit 13. Resilient sleeve member 27 
is in the relaxed position disposed about stem 19. FIG. 6 shows 
corporation stop 11 after insertion, but prior to having been moved into 
sealing engagement with host conduit 13. Compression ring 37 has been 
placed within opening 42 of saddle 53, such that tabs 41 (not shown) of 
saddle 53 align with notches 39 of compression ring 37. Clamp nut 55 is 
threaded about the upper extent of neck portion 23 but has not been 
tightened fully. Lower end 31 of sleeve 27 has not been expanded over 
conical head portion 21 of threaded stem 19. 
FIG. 7 shows the completed installation, which is accomplished by 
tightening clamp nut 55, preferably by using a deep socket or some other 
mechanism on the standard drilling and tapping mechanism. The socket will 
generally include a robber insert with an opening for releaseably holding 
neck portion 23 of threaded stem 19. As clamp nut 55 moves down neck 
portion 29 of threaded stem 19, lower end 31 of sleeve 27 is flared 
outwardly, thereby engaging the opening in liner 17 and conduit 13, 
thereby clamping liner 17 to the internal sidewall of conduit 13 and 
eliminating any gaps which might be present in the annular region 49 
between liner 17 and conduit 13. Compression ring 37 spreads the 
installation forces applied by clamp nut 55 over an area on the external 
sidewalls of the conduit. The resilient sleeve upper end 29 forms an 
external seal between the inner surface of compression ring 37 and 
external sidewalls of host conduit 13. 
When clamp nut 55 is engaged with neck portion 23 of threaded stem 19 and 
turned conical head portion 21 of threaded stem 19 is forced upwards into 
lower end 31 of sleeve member 27. Clamp nut 55 must be allowed to turn 
about threaded stem 19 without turning compression ring 37 as well. 
Slippage of either compression ring or saddle 53 will result in clamp nut 
55 not being tightened sufficiently and a seal not being formed. The 
apparatus of this invention does not include an enlarged washer as shown 
in the McMillan patent, which washer is contoured to fit against the outer 
surface of host pipe 13 so as to avoid slippage, because its size is 
incompatible with standard drilling and tapping machinery. Instead, stop 
11 in accordance with the invention uses a mating connection between 
compression ring 37 and saddle 53. As discussed above, compression ring 37 
is placed within opening 42 of saddle 53 such that notches 39 formed in 
the outer edges of compression ring 37 align with tabs 41 formed in inner 
edge 54 of opening 42 of saddle 53. When clamp nut 55 is tightened around 
upper end 29 of stem 19, it will tend to frictionally pull compression 
ring 37 in the same direction as clamp nut 55 is being turned. At that 
point, tabs 41 on inner edge 54 of saddle 53 engage notches 39 on the 
outer edges of compression ring 37 and prevent compression ring 37 from 
being turned along with clamp nut 55. Key 75 is engaged within keyway 71 
in compression ring 37 and keyway 73 in neck portion 23 of stem 19. Clamp 
nut 55 thus turns alone on stem 19 and pulls enlarged head 21 of threaded 
stem 19 upwards so as to expand sleeve member 27 and make a seal with 
opening 45 and stationary compression ring 37. Once clamp nut 55 has been 
tightened to a predetermined torque, the seal is effected and installation 
has been readily and efficiently accomplished. 
After the seal has been made and corporation stop 11 has been installed, 
drilling and tapping machinery 61 is removed from stop 11. In addition, 
once installation machinery 61 has been unstrapped from conduit 13, saddle 
53 and the rubber gasket underneath it may also be removed from around 
installed compression ring 37. An external view of installed corporation 
stop 11 (FIG. 1), after saddle 53 and the rubber gasket have removed, 
shows upper end 29 of stem 19, clamp nut 55 and compression ring 37. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in carrying out the above process, in 
the described product, nd in the construction(s) set forth without 
departing from the spirit and scope of the invention, it is intended that 
all matter contained in the above description and shown in the 
accompanying drawing(s) shall be interpreted as illustrative and not in a 
limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.