Note: Descriptions are shown in the official language in which they were submitted.
~ z~
This is a division of Canadian patent application
Serial No. 292,545 which was filed on 7 December 1977.
BACKGROUND OF THE INVENTION
. . _
The present invention relates to improvements in pipe
sections having couplings on the end thereof. In another
aspect, this invention relates to an improved pipe section
having couplings which allow at least one full turn of a
relative axial rotation between connected sections while
providing effective sealing. According to another aspect
the present invention relates to an improved pipe section
having indicia thereon for indicating proper engagement of
the sections. According to an even further aspect, this
invention relates to an improved pipe section having a
requiréd makeup torque for effective sealing which is in
the range of application by hand by one worker without the
necessity of using equipment,` tools and the like.
In the provision of piping systems such as in oilfield
flow line pipe applications, it has been common to use
pipe sections having threaded couplings on the end thereof
for interconnecting the sections to form the system. It
has also been typical to utilize pipe sections formed from
resin impregnated filament wound materials to form the
pipe sections such as is disclosed in the U.S. patents to
McLarty, 3,572,392, issued March 23, 1971; Carter, et al.,
3,784,239, issued January 8, 1974; and Meher, 3,540,757,
issued November 17, 1970. These filament wound sections
have proved particularly advantageous for use in an
oilfield flow line pipe environment because of their light
weight, ability to withstand the pressure ranges of this
use and because of their non-corrosive nature.
- 2 -
i~Z~
r~
The use of non-corrosive pipe sections has been
hindered by problems present in effectively joining the
sections of pipe together. One method of assembling the
same is to lay the sections of pipe at the place of
intended use and then connect the sections by bonding with
- adhesive.
This method of assembly poses problems such as the
necessity of forming a complete bond betweèn the sections
to provide an effective seal and the necessity of waiting
while one bond is taking place before the next section can
be positioned and connected. In addition, these
connections are made under less than ideal conditions
wherein contamination may reduce the integrity of these
connections.
To eliminate these bonded joints, systems such as is
disclosed in the above-identified U.S. patent to Carter,
No. 3,784,239, have been attempted wherein threaded
connections are made to couple the sections together.
The sections using threaded connections also possess
problems in that resin impregnated filament pipe sections
do not lend themselves well to the use of wrenches. When
wrenches are used they tend to compress the pipe, which
may result in damage to the pipe that would later cause a
failure of the section. In addition, it is sometimes
necessary to utilize fittings in the pipe sections such as
an elbow to make a right hand turn in the pipe system. It
has been found that it is extremely difficult to provide
effective sealing between these screw type joints while
orientating the fitting in the required direction. One
method that has been attempted to alleviate this problem
`\ ~z~
is to cut a section of pipe and bond an elbow or another
type of fitting to the end thereof. Unless this bonding
is accomplished after the pipe is installed the orientation
of the fitting in the proper direction cannot be assured.
In addition, if the bond is formed after the section is
coupled the additional risk of contamination of the bond
occurs.
Thus, although these resin impregnated filament pipe
sections have advantages, they are very difficult to use
and install.
SUMMARY OF THE INVENTION
Therefore, there is provided according to one
embodiment of the present invention an improved resin
impregnated filament pipe section having male and female
threaded couplings formed on the ends thereof which can be
interconnected by hand.
The present invention also contemplates the use of an
improved pipe section in which a connection between
sections provides at least one full turn of relative axial
adjustment between the sections while prov-iding an
effective seal.
In addition, the present invention contemplates the
use of an improved pipe section having indicia on the
exterior thereof indicating to the worker installing the
sections when sufficient engagement of the threads is
present.
In accordance with an aspect of the invention there is
provided an oilfield flow line pipe section with
connection means on the end thereof for releasably
connecting a plurality of sections together in series,
said section comprising: a length of tubing, mating male
and female threads formed on said tubing adjacent to ends
thereof for use in releasably connecting sections
together; a compressible seal means carried by said tubing
adjacent one end thereof for sealing connections to other
sections; a frusto-conical sealing surface means formed on
the tubing adjacent the end opposite said compressible
seal means for sealingly engaging said seal means on an
adjacent connected section; and wherein the apex angle of
- the cone of the sealing surface, the compressibility of
the seal, the lead of and the friction between the threads
and the outside diameter of the pipe are so interrelated
that the necessary torque to connect the sections together
by threaded engagement and to provide an effective seal by
compression of the seal means is less than the torque an
ordinary worker can apply solely by hand to the section
whereby hand makeup of the connection is possible.
The present invention taken in conjunction with the
invention described in Canadian patent application Serial
No. 292,545 which was filed on 7 December 1977, will be
described hereinbelow in detail with the aid of the
accompanying drawings, in which:
~1~;28~3
11
B6313 - 1¦
!I BRIEF DESCRIPTION_OE THE DR~IIINGS
!I The present invention will be readily appreciated by
i!those of ordinary skill in the art as the same becomes better
llunderstood by reference to the following detailed description when
i¦considered in connection with the accompanying draw;ngs in which:
¦¦ FIGURE 1 i5 a side elevation vie~ of the improved pipe
¦section of the present invention;
FIGUR~ 2 is an enlarged elevation view of the male or
llpin end of the i~proved pipe section of FIGU~E l;
FIGURE 3 is an enlarged sectional view of the female or
socket end of the section illustrated in FIGURE 1 drawn to the
sa~e scale as FIGURE 2;
FIGURE 4 is a partial longitudinal section of a
l connection between two of the sections illustrated in FIGURE l;
1 FIGURE 5 is a partial enlarged sectional view of the
¦ connected pin and socket ends of two sections of tubing
¦illustrating the threads of the two ends engaged to the point of
initial effective sealing; and
FIGUP~E 6 is a view similar to FIGURE 5 illustrating the
ends comp etely eng~ged.
- 6 -
z~
B6313
~,DESCRIPTION OF THE_PREFERRED_E~IBODIl!ENT
Referring now to the drawings, wherein like reference
characters designate like or corresponding parts throughout the
~several views, there is shown the improved pipe section of the
ijpresent invention, which for purposes of this description is
,¦identified by reference numeral 10. The section 10 is provided
¦!with a female, socket or bell end 12 and a male pin or spigot end
14 joined together by a central tubing portion 16. The ends 12
!,and 14 have appropriate rnatins threads. The section 10 can be
l¦constructed in accordance with a conventional method from resin
Iimpregnated fiber material.
¦¦ The section 10 can be used in numerous environments,
¦¦such as in an oilfield flow line pipe system. When the section 10
llis used as an oilfield flo~ line pipe the sections are constructed
Il¦with an end to end len~th!of approximately twenty feet and are
made in 2 inch, 3 inch and ~ inch and other standard pipe sizes.
In an oilfield using pipe system a number of the sections 10 are
,connected together in series by use of the male and female ends.
~¦According to a particular feature of the present invention, the
2~ section 10 is constructed in such a manner that it can be
¦iconnected to another section by hand without the use of special
¦iequipment or tools. In addition, couplings can be releasably made
¦Ito allow disassembly and reuse. No permanent bonds at the joints
l¦are necessary to provide an effective seal between the sections.
!It is to be understood, of course, that standard
f i tt ing s not sho~ n ~ w i th th r ead s m a t ing th e th r ead s o ~ th e
1! 7 _ I
l l 1
l! l
~ 2~
1i !
B6313 .l
!Isection 10 can also be provided. When the dimensional
Irequirements of the environment of use of the sections are such
Ilthat a right angle fitting is required at the end of one of the
sections, a fitting can be provided with mating threads to engage
~one of the ends of the section 10. ~Yhen a fitting is required at
¦a spacing located intermediate the length of one of the pipe
sections, the section can be cut and a fi.ting such as a right
¦¦angle fittlng bonded onto the sectlon at the desired location.
. According to another particular feature of the present
: 10 invention,.an adjustability is provided in the couplings to
provide effective sealing between fittings and sections while
. lallowing the fittings to be positioned in any desired radial
. ¦direc~ion.
¦¦ In addition, as will be hereinaf~er described in detail,
¦~the section 10 is provided with indicia on the outside thereof
¦which indicate when a joint is properly made up to provide an
¦effective seal. These indicia allow t.he workmen installing the .
¦pipe to quickly determine when a proper coupling is made between
the various sections and fittings.
The socket end 12 and pin end 14 will be described in
i detail by referring to Figures 2 through 6.
Referring particularly to Figure 2 that details of
construction of the pin end 14 will be described. As can be seen,
Ithe central tubing portion 16 is flared at 18 to form the pin end
25 ~14. The pin end 14 has a larger wall thicl;ness than the central
¦Itubing portion 16, but the internal diameter of the central tubing
portion 16 is continuous or equal completely through the pin end
~ _.g_
-
9~ z~
1~ b ~
14. The flared portion 1~ extends from the tubing portion 16 to a
guide alignment portion 20 formed on the exterior of the section.
The guide portion 20 is frusto-conical shaped and converges in a
,direction toward the pin end of the section. The frusto-conical
isection 14 has an apex angle A. A male threaded portion 22 is
formed on the exterior of the pin end 14 adjacent to the guide
¦lportion 20. In the preferred embodiment the threads 22 have a
arcurate cross-section and are bounded on one side by the guide
Ipor.ion 20 and on the other side b~ a second guide portion or seal
¦carrying surface 24. Portion 24 is frusto-conical shaped and in
¦¦the preferred embodiment its apex angle is equal to A.
Il A groove 26 is formed in the second guide portion 24 and
¦is of a size and shape to receive an annular compressible seal 28
itherein. This seal 28 is eliminated from Figure 2 for purposes of
l¦description but is shown in Figures 4 througll 6.
¦ Referrinq now to Figure 3, it can be seen that the socl;el-
end 12 is formed by flared portion 40 which extends frorn the
central tubing portion 16. A sealing or seal engaging surrace 42
lis formed on the interior of the flared portion 40 and has a
¦ frusto-conical shape with an apex angle ~ . In the preferrea
embodiment of the angle 9 equals the angle A and surface 42 is
appropriately dimensioned to cooperate with the guide portion 24
Icarrying the seal 2~. Surface 42 provides an annular seal
iengaging surface of the seal 2~ to seal the connection of two
sections. As can be seen in ~igure 3 the wall thic~ness of the
socket el~ 12 increases over the wall thickness of the central
il !
I' .
B6313
interior of the end 12. The threads of portion 44 are selected of
a size to provide threaded engagement with the threads 22 and to
allow innerconnection of two sections 10 together. Threads 44
have an arcurate cross-section corresponding to the cross-
, section of the threads 22.
A guide or alignment portion ~6 is formed adjacent to the
¦,portion 44 and extends to end 52. Portion 46 is frusto-conical
lshaped and has an apex angle B. In the preferred embodiment apex
llangle B is equal to the apex angle A of the portion 20 and angle
¦1 of portion 42. This surLace or portion 46 is closely
dimensioned to the major pitch of the threads 22 and the guide
portion 20 and thus when two sections of pipe are being coupled
'together the threads 22 and portion 20 engage and are guided by
¦surface 46 to provide axial alignmen'; of the two sections and
!contributes to the proper alignment of the threads 22 and 44 to
¦!prevent cross-threading thereof. This alignment function of the
¦engaging surfaces on the ends 12 and 1~ facilitates the connection
¦process and reduces the time and labor required to make such an
¦assembly.
¦ According to a particular feature of the present
linvention end 14 is provided with indicia on the exterior thereof
¦jin the area of the guide portion 20 to indicate the amount of
telescope threaded engagement of the two sections during the
l¦assembly process. These indicia in the pre~erred embodiment
li appear as axially spaced lines 48 and 50 extending around the
surface 20 as shown in Figure 4. During connoction Oe the end 14
o-
2Z~
B6313 ,1
of the section 10 and the end 12' and section 10' the end 52' will
jfirst align with the indicia 48. Further engagement of the thread
'will cause end 52' to align with the indicia 50.
I~ According to a particular feature of the present
,linvention when the end 52' aligns with the indicia 48 effective
sealing is present in the pipe and the workman knows that he is
beginning the area of acceptable engager1ent for an effective
,sealing. Further relative axial rotation of the section 10 and
¦10' will cause the seal 2~ to move longitudinally into the section
¦12 in the direction of arrow 5~ while re.~aining in contact wiLh
¦the surface 42. Since the surface 42 tapers inwardly as shown in
I Figure 3 further movement in the direction of arrow 54 will cause
¦ addition21 compression of the seal 28. Tllis tightening o the
~¦sections can be continued until the end 52' aligns with the
indicia 50, thus indica',ing to the wo.kman that the ~wo sections
are completely engaged. To ali~n a fi~ting on the end of one of
the sections 10 or 10' in a desired diroction the threaded
!engagement can be unscrewed or bac~ed off to some extent. The
¦¦workman knows by observing the indicia how far the two sections
l¦can be backed off while still maintaining an effective seal.
¦ According to a particular feature of the present
invention the relative rotation between the two sections provided
Ibetween the two indicia 40 and 48, is at least one full turn or 360
l¦degrees. This feature provides for orientation of the fitting on
,¦the end of the section in any direction while still maintaining an
- effect_ve seal. This is accomplished by lelating the lead of the
Il I
Il l
4~
L~V~
threads 22 and 44 and the angle of the sealing surface 42 such
¦that the allowable diametric clearance between the surface 24 and
jthe surface 42 is within the operational range of the seal theough
',at least 360 degrees of relative rotation between the two sections.
~~ The structure providing this will, be described in more
detail by reference to Figures 5 and 6 which are enlarged views of
two threads. In Figure S, sections 10 and 10' are shown
~¦inter-engaged to the poin~ where the seal 28 has been sufficiently
l',compressed by the surface 42' to a point where the diametric
¦!clearance hetweell the surfaces 24 and 42' is equal to ~0. As
¦shown, the sections 10 and 10' are threadedly engaged to a point
where at least one full turn or one thread of engagement remains
before full engagement. By appropriately dimensioning the size
and axial posi~ion of surfaces 24, 42' and the threads, the diame-
!~tric clearance El can be selected ~o be within the acceptable
¦Idesign parameters of the particular seal 2~ to provide an effective
seal between the surfaces 24 and ~2~. In the preferred emhodiment
¦Ithe configuration in Figure 5 ~rould be reached when the end 52'
is in alignment with the indicia 48. Thus, the workman performing
Ithe assembly of the sections wo~ld know that he had reached the
,point where an effective seal was present between the sections 10
land 10'. Further relative axial rotation of the sections would
licause further axial movement of the section and seal 28 in the
!Idirection of arrow 54 into the section 10'. Since the surface 42
¦iis frusto-conical shaped and has an apex angle 9 the seal will be
¦further compressed by this movement.
¦ In Figure 6 the sections 10 and 10' are shown with ~ull
hread engagement of the two sections and the seal ~oved further
Il .
~1 - 12 -
~Z~
~6313 !l
into section 10' to a point ~JI-Iere the diametric clearance E is
virtually zero. ~y selecting tlle lead L such that the diametric
clearances E is within the design parameters of the particular
,seal 28-during an a~ial movement o~ distance L or within one
ithread o full makeui>, one comp]ete rclative revolution of the two
sections can be obtained ~7hile providing effective scaling there-
bet~een. It has been found that the aj?e~: angle ~ of the sealing
¦isurface is less th2n t}le angle X ~lhere tall X = E/L~ L is.equal to
¦the lead of the thread and ~ i5 eq~ial to the maximum allo~/able
'diametric clearance. In the pr~sent embodiment the effective
. !diametric clearance, E, for the particular seal 2~ is maintained
through one complete relative revolution of the t~70 sections when
the thread lead, L = .25 inch and the angle ~ is 0 degrees and 30i
I Thus the pipe section of the present invention provides
lends which can be connected to another section and provide at
. ¦least 360 degLees of rela'cive a~:ial adju.stment bet~ecll the
sections ~h ile providing an ef~ective sealing.
¦ In accordance with another aspect of the present
¦invention it has been found tha~ by relating the apex angle of the
20 . ¦sealing sur~ace to the lead of the tl-reads that the torque
required to make up a joint to provide an e~fective seal can be
. lless than the torque an ordinary ~orker can apply solely by hand
to the sections whereby the hand makeup of the connections are
Ipossible. By reducing the ape~ angle and decreasing the lead the
l¦amount of torque required can be reduced. In the present inven-
¦tion the provision of a seal engaging sul-~ace 42 ~hose ape~ angle
¦~ is 0 degrees and 30 min. and thread with a lead of 1/4 in/rev.
'provided a mechanical advantage such that the torque which must be
I
, -13-
.
``
1~ Z~
!
~6313
¦!applied to the sections necessary to compress the seal is within
the range of possibility of one worker applying a torque to the
pipe by hand withou. the use of additional e~uipment or tools.
It has been found that the makeup torques for joints of
S ,this type for 2 inch pipe is in the range of 70 to 90 inch pounds.
¦IIn the present embodiri~ent the makeup torque is 80 inch pounds.
11 the abo-~e torques are in the ranqe which can be applied by
ihand by an ordinary worker to the exterior of the pipe without
lltools. In a 3 inch pipe it has been fo~nd that the torque in the
¦Iran~e of 110 to 130 inch pounds can be applied by hand. In such a
i3 inch e~bodiment the makeup torque is 120 inch pounds. In the 4
~¦inch pipe a torque in the range of 140 to 160 inch pounds can be
¦applied by hand, with present embodiment the makeup torque is lS0
llinch pounds.
!1 It is believed that other sizes could be designed which
would have a necessary ma~eup torque in the range that can be
¦applied by an ordinary worker without the use of equipment or
l¦wrenches or the lil~e.
¦I Therefore, according to the present invention, a pipe
llsection is provided which is versatile in application, in that,
¦the joints between the sections and the joints between the
sections and fittings are such that 360 degrees of axial relative
j!rotation between sections can be provided to allow for adjustment
¦¦of the directions of fittings on the end of the sections. This is
llacco~plished by rela,ing the ape~ angle of the sealing surface to
the dia~,etric cle~rence of the seal and the lead of the scre~/.
~1 1
~2~48
B6313 ,¦
~! In addition, the pipe section of the present invention
,'is particularly designed and the lead of the threads, sealing
surface apex angle and compressibility of the seal aee selected to
allow the sections to provide hand makeup thus reducing the amount
I.. of labor and time required to properly ins~all the sections and
eliminating the possibility of damaging the pipe ~Jith orenches.
In addition, the improved pipe section of the present invention
'provides an indicia on the exterior of the pipe to indicate to the
'~rorker ~rhen the sections are proper.ly connected.
I It should be understood, of course, that the foregoing
disclosure relates only to a preferred embodiment of the present
¦invention and that numerous modifications or alterations may be
¦made therein without depa~ting from the spirit and scope of the
invention as set forth in the appended claims .
Ii .'
Il . '' .
jl - 15 -
