Note: Descriptions are shown in the official language in which they were submitted.
1~2~L7
This ;s 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
- required 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
~IcLarty, 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 -
1 28~7
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 between 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
2~
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 providing 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 in an oilfield flow line pipe section with
connecting means on the ends thereof for conneeting a
plurality of sections together in series, having a length
of tubing, mating male and female threads formed on said
tubing adjaeent the ends thereof for use in eonneeting
sections together; a compressible seal means mounted on
said tubing adjacent one end thereof, sealing surfaee
means formed on said tubing adjaeent the end opposite the
eompressible seal means, the improvement whieh eomprises
means mounting said seal means for providing effeetive
sealing during at least one full turn of relative axial
rotation between two eonnected sections.
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:
~2~
B6313 1~
!I BRI_F_DESCRIPTION OF THE DR~I~INGS
!I The present invention will be readily appreciated by
j~those of ordinary skill in the art as the same becomes better
llunderstood by reference to the following detailed description when
llconsidered in connection with the accompanying drawings in ~Ihich:
! FIGURE 1 is a side elevation view of the improved pipe
¦~section of the present invention;
il FIGURE 2 is an enlarged elevation view of the male or
llpin end oE the improved pipe sec~ion of FIGU~E l;
FIGURE 3 is an enlarged sectional view of the female or i
socket end of the section illustrated in FIGURE 1 drawn to the
same scale as FIGURE 2;
FIGURE 4 is a partial longitudinal section of a
l connection between two of the sections illustrated in FIGURE l;
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
¦ FIGUR~ 6 is a view similar to FIGURE 5 illustrating the
enos completely engaged.
2~
B6313 1,. !
~jDESCRIPTION OF THE PR~FER~ED Et~BODIll~NT
j; _ ____-- _ ___ __ __________ ____.__ __ _ __ ___
Referrin~ 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
''present invention, which for purposes of this description is
,¦identified by reference numeral 10. The section 10 is provided
¦Iwith 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 r,latins threads. The section 10 can be
lliconstructed in accordance wit]l a conventional me.hod from resin
impregnated fiber material.
~¦ The section 10 can be used in numerous environments,
¦llsuch as in an oilfield flow line pipe system. When the section 10
¦!is used as an oilfield flow line pipe the sections are constructed
ll~with an end to end length!of approximately t~lenty feet and are
Imade 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
I,section 10 is constructed in such a manner that it can be
jiconnected to another section by hand without the use of special
¦iequipment or tools. In addition, couplings can be releasably made
¦I to allow disassembly and reuse. No permanent bonds at the joints
llare necessary to provide an effective seal between the sections.
¦ 1t is to be understood, of course, that standard
¦fi tings tnot shown) with thr-ads mating the th~eads oE the
~z~
B6313
'lsection 10 can also be provided. ~1hen the dimensional
requirements of the environment of use of the sections are such
that a right angle fitting is required at the end of one of the
~isections, a fitting can be provided with mating threads to engage
,one of the ends of the section 10. When a fitting is required at
¦la spacing located intermediate the length of one of the pipe
sections, the section can be cut and a fitting such as a right
¦angle fitt~ng bonded onto the sectlon at the desired location.
According to another particular feature of the present
invention, an adjustability is provided in the couplings to
provide effective sealing bet~een fittings and sections while
allowing the fittings to be positioned in any desired radial
direc~ion.
~ In addition, as will be hereinafter described in detail,
¦I the section 10 is provided with indicia on the outside thereof
¦which indicate when a joint is properly ~ade up to pro~ide an
¦effective seal. These indicia allow the workmen installing the
pipe to quickly determine when a proper coupling is ~nade between
the various sections and fittings.
The socket end 12 and pin end 14 will be described in
detail by referring to Figures 2 through 6.
Referrin~ 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
1~14. The pin end 14 has a larger wall thicl;ness than the central
,tubing portion 16, but the internal diameter of the central tubing
¦portion 16 is continuous or equal completely through the pin end
2~7
'14. The flared portion 18 extends from the tubing portion 16 to a
guide alignment portion 20 forrned 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 ape~ angle ~. A male threaded portion 22 is
,¦formed on the exterior of the pin end 14 adjacent to the guide
¦¦portion 20. In the preferred embodiment the threads 22 have a
~arcurate cross-section and are bounded on one side b~ the guide
¦por.ion 20 and on the other side by 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.
¦ 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
lltherein. This seal 28 is eliminated from Figure 2 for purposes of
lldescription but is shown in Figures 4 through 6.
¦ Referring now to Figure 3, it can be seen that the socl:el-
end 12 is formed by flared portion ~0 wllich extends from the
¦central tubing portion 16. A sealing or seal engaging surrace 42
iis $ormed on the interior of the flared portion 40 and has a
!frusto-conical shape with an apex angle ~ . In the preferred
embodiment of the angle 9 equals the angle A and surface 42 is
appropriately dimensioned to cooperate with the guide portion 24
carrying the seal 28. Surface 42 provides an annular seal
jengaging surface of the seal 28 to seal the connection of two
Isections. As can be seen in ~igure 3 the wall thic~ness of the
socket erd 12 increases over the wall thickness of the central
,~ _ g _
i, .
!,
~ 2~g7
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
i have an arcurate cross-section corresponding to the cross-
S ', section of the threads 22.
il A guide or alignment portion ~A6 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
iangle B is equal to the apex angle A of the portion 20 and angle
¦ of portion 42~ This sur~ace or portion 46 iS closely
dimensioned to the major pitch of the threads 22 and the guide
portion 20 and thus when two sections o~ pipe are being coupled ,
Itogether the threads 22 and portion 20 engage and are guided by
~ ¦surface 46 to provide axial alignment of the two sections and
Icontributes to the proper alignment of the threads 22 and ~4 to
prevent cross-threading thereof. This alignment function of the
engaging surfaces on ~he en~s 12 and 1~ facilitates the connection
process and reduces the time and labor required to make such an
lassembly.
I According to a particular feature of the present
linvention end 14 iS provided with indicia on the exterior thereof i
¦!in the area of the ~uide portion 20 to indicate the amount of
¦!telescope threaded engagement of the two sections during the
l¦assembly process. These indicia in the preferred embodiment
lappear as axially spaced lines 48 and 50 extending around the
Isurface 20 as shown in Figure 4. During connection of the end 14
l - 10 -
~2~7
B6313
of the section 10 and the end 12 and section 1~' the end 52' will
first align with the indicia 48. Further engagement of the thread
will cause end 52' to align with the indicia 50.
! According to a particular feature of the present
~! invention when the end 52' aligns with the indicia 48 effective
sealing is present in the pipe and tlle workman knows that he is
beginning the area of acceptable engagem,ent for an effective
sealing. Further relative axial ro~ation of the section 10 and
110' will cause the seal 28 to move longitudinally into the section
¦12 in the direction of arrow 5~ while remair,ing in contact with
the surface 42. Since the surface 42 tapers inwardly as shown in
Figure 3 further movement in the direction of arrow 54 will cause
¦adflition21 co~pression of the seal 28. lhis tightening of the
¦sections can be continued until the end 52' aligns with the
¦indicia 50, thus indica~ing to the workman ~hat the ~wo sections
¦are completely engaged. To align a fitting on the end of one of
¦the sections 10 or 10' in a desired direction the threaded
lengagement can be unscrewed or backed off to some extent. The
¦workm~n knows by observing the indicia how far the two sections
llcan 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
between 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
j~the end of the section in any direction while still ~aintainlng an
~efective seal. This is accomplished by relating the lead of the
-11- ' 'I
il 1.
.f)2~47
~ v ~
I!threads 22 and 44 and the angle of the sealing surface 42 such
i,that the allowable diametric clearance bet~een the surface 2~ and
,1
the surface 42 is within the operational range of the seal through
Ilat least 360 degrees of relative rotation between the two sections.
~~ The structure providing this will be described in more
ldetail by reference to Figures 5 and 6 which are enlarged vie~s of
- Iltwo threads. In E~igure 5, sections 10 and 10' are shown
¦¦inter-engaged to the poin~ where the seal 2R has been sufficiently
l'compressed by the surface 42' to a point where the diametric
Illclearance bet~een the surfaces 24 and 42' is equal to Eo~ As
¦shown, the sections 10 and 10' are threadedly engaged to a point
¦Iwhere at least one full turn or one thread of engagement remains
¦,before full engagement. By appropriately dimensioning the size
l and axial position of surfaces 24, 92' and the threads, the diame-
! tric clearance El can be selected ~o be within the acceptable
design parameters of the particular seal 2~ ~o provide an effectiv~
seal between the surfaces 24 and 92'. In the preferred embodil~ent
the configuration in Figure 5 ~lould be reached wl-en the end 52'
lis in alignment with the indicia 98. Thus, the workman performing
Ithe assembly of the sectiolls would know that he had reached the
point where an effective seal was present between the sections 10
land 10'. Further rélative axial rotation of the sections would
liicause further axial movement o~ the section and seal 28 in the
!idirection of arrow 54 into the section 10'. Since the surface 42
¦is frusto-conical shaped and has an apex angle 9 the seal will be
¦further compressed b~ this movement.
¦ In Figure 6 the sections 10 and 10' are shown with full
Ithread engagement of the two sections and the seal moved further
11,
1 Z~L7
~6313 !l
il into section 10' to a point wherc the diametric clearance E is
Ivirtually zero. By selecting the lead L such that the diametric
clearances E is ~ithin the design parameters of the particular
seal 28 during an axial movement o~ distance L or within one
ithread o~ fu]l ~nakeup, one complete relative revolution of the two
sections can be obtained while providing effective sealin~ there-
!'bet~een. It has beerl found that the apex angle 0 of the sealing
~ D X~ 9O
surface is less than ~he angle ~ ~there ~an X - E/L~ L is equal to
Ithe lead of the thread and E is eq~ial to the ~aximum allo~table
Idiametric clearance. In the present embodiment the efective
. !diametric clearance, E, for the particular seal 2~ is maintained
~through one complete relative revolution of the t~!o sections ~hen
the thread lead, L = .25 inch and the angle ~ is 0 degrees and 30'
I Thus the pipe section of the present invention provides
lends which can be connected to anotler section and provide at
jleast 360 de~.-ees of relative a~:ial adjus~ment bet\teen the
sections while providing an ef~ective sec)ling.
¦ In accordance with another aspect of the present
linvention it has been found that by rela~ing the apex angle o~ the
¦sealing 5urface to the lead of the threacls that the torque
required to ma~e up a joint to provide an effective seal can be
less than the torque an ordinary ~torker can apply solely by hand
to the sections whereby the hand makeup o~ the connections are
Ipossible. By reducing the ape~ angle and decreasing the lead the
1 amount o~ torque required can be reduced. In the present inven-
tion the provision of a seal en~aging surface 42 whose apex angle
is 0 degrees and 30 min. and thread \-ith a lead of 1/~ in/rev.
provided a mechanical advanta9e such that th,e torque \~hich must b~
~L~ Z~4~
B6313 1!
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 witho~, the use of additional equipment or tools.
!! It has been found that the ma~eup torques for joints of
,this type for 2 inch pipe is in the range of 70 to 90 inch pounds.
In the present embodirilent the makeup torque is 80 inch pounds.
ll the above torques are in the range which can be applied by
jihand by an ordinary t~orker to the exterior of the pipe without
¦1tools. In a 3 inch pipe it has been found tllat the torque in the
¦Irange of llO to 130 inch pounds can be applied by hand. In such a
1~3 inch embodiment 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
¦lapplied by hand, with present embodi~ent the makeup torque is 150
11inch pounds.
!1 It is believed that other sizes could be desiqned which
¦¦would have a necessary makeup torque in the rallge that can be
¦applied by an ordin3ry worl~er Witl1out the use of equipment or
l¦wrenches or the lile.
¦1 Therefoee, according to the present invention, a pipe
!jsection 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
;1rotation between sections can be provided to allow for adjustment
¦1of the dir~ctions of fittings on the end of the sections. This is
1lacco~.plished by rela.inq the apex angle of the sealinq surface to
Ithe dia~,etric clearance of the seal and the lead of the screw.
,
Z~7
B6313 ll
~¦ 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 are selected to
allo~ the sections to provide hand makeup thus reducing the amount
Iof labor and time required to properly install the sections and
eliminatinq the possibility of damaging the pipe ~lith wrenches.
In addition the improved pipe sec~ion of the present invention
"provides an indicia on the exterior of the pipe to indicate to the
l'worker when the sections are properly connected.
,1 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
~linvention as s.t iorth in the appended clairs.
: jl ' . ' '.
Il - 15 -
