Note: Descriptions are shown in the official language in which they were submitted.
~0~3~
Thi~ invention relate~ to a proce~ of and apparatus
for linLng metal pipes, so a9 to provide the pipes with a
protective elaetomeric lining.
The tran~mi~sion of fluids, ~uch as ore su~peneions,
chemical treatment liquid~ and the like by means of pipelines
is well known and well accepted. It is a relatively -~i~ple
and economical means of transmis~ion of such materials con-
tinuously over long distances. Howover, in cases where abrasive
liquids such as mineral ore and coal ~lurries or corrosive
liquid~ such as acids have to be transmitted, heavy demands
are placed upon tho ~teel pipe sectio~ compri~ing the pipe-
line. If the pipe ~ections are to withstand the action of
~u¢h materials for extended periods of time, to reduce co~ts
of maintenance, repair and replacement of the pipe ~e¢tion~,
they noed to be provided with some form of protection, particu-
larly at bends and elbows in the pipeline where abra~ive wear
i~ particularly ~evere. It is thus known to provide pipelines
with inner 1 ning of resilient material, normally natural or
synthetic rubber, as protection against internal abrasion and
corrosion, to prolong the service life of the steel pipe
~ections.
The present invention provides a method and apparatu~
whereby steel pipe sections may be provided with ~nternal
rub~er linings, the lining~ being of synthetic rubber of a
type which can be applied to the pipe in the uncured state as
a flowable liquid, but which cures to re~ilient rubber in
situ after application, without application of heat or special ~- -
curing conditions.
According to a fir~t agpect of the present invention,
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1C)~3~44
there is provided a process for providing metal pipes with
elastomeric lining which comprises dispos~ng within the ~;
metal pipe an axially movable applicator, the applicator
compri~ing a forward member movable rela~ve to the pi~e and
disposed to maintain close co-operation with the inside surface
of the pipe around substantially the entire inner periphery
thereof, and a rearward member di6po~ed to leave a space
between the forward member and the rearward momber, said
rearward m~mber boing arranged to leave a peripheral gap of
prodetermined size between its outer edge and the ins~de
~urace of the plpe; supplying flowable composition which is
curable at room temperatures to an ela~to~er, to ~aid ~pace;
~oving the applicator forward relative to the pipe; regulating
the ~upply of composition to the appl~cator ~o as to allow
~proadinq of the compo~ition onto the in~ide urfac~ o~ the
pip- by tho r-arward member cont$nuou~1y a~ the applicator
~ov ~ forward r-lative to the pipe; removing the applicator
fro~ within the pipo: and allow$ng the compo-ition to cure on
the inside ~urface of the pipe to provide an ela~tomeric
l~ning ther-on
According to a 6econd aspect of the inv~ntion, there
i8 provided an apparatus for providing metal pipo~ with ela~to-
meric lin ng which comprises an applicator adapted to be di~-
po~d with~n and axially movable relative to the metal pipe to
be lined, said appl$cator comprising a forw~rd member movable
relative to the pipe and disposed to maintain clo~e co-operation
w$th the inside surface of the pipe around substantially the
entire inner periphery thereof, and a rearward member aisposed
to loave a ~pace between the forward member and the rearward
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member, ~aid rearward ~ember beLng adapted 80 as to leave a
peripheral gap of predetermined size between its outer edge
and the inside 8urface of a pipe to be lLned; means for sup-
plying flowable composition to ~aid spa~e; means for ~oving
~aid applicator axially forwardly relative to the pipe to be
lined whilst flowa~le composition i8 supplied to said space.
lhe applicator used ~n the pre~ent invention pre-
ferably ha~ a rearward member which prosonts a frusto-conical
peripheral outer surface to the inside surface of the pipe,
the frusto-conical surface taper~ng in the forward diroction.
By the~e means, even, continuous, smooth spreading of the
liguid composition on the pipe inner wrfacc is accomplished,
~ the appl~cator moves relative to the pipe, the lining thick-
ne~ b-~ng dotermined by the gap betwoen tho edge of the p ri-
ph~ral fru-to-conical ~urface and the ~n~ido ~urface of the
plpe.
~ he forward membor of the applicator i8 proforably
of plate-like form, and ~orves to define a ~pace to which
~ curable composition is delivered. In one preferr-d embodiment,
; 20 the forward m~mber leaves a ~m~ll peripheral gap between it~
~ -,
outor periphory and the in~ide ~urface of the pipo to be lined.
~he size of the 8mall gap i8 less than the thickness of the
lin~ng to be depos~ted. Thus the gap allow~ some deposition o
~terial on the inside surface of the pipe ahead of the forward
member, under certain conditions. The provigion of this gap
allows for changes in the flow rate of the composition to the
pace of the applicator head, by preventing generation of
exc-ss pres6ures in 6aid 6pace. In another prcferred embodi-
ment, the forward me~ber is provided with an annular sliding
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1~3~i~4
seal of hard re~ilient materlal, e.g. hard rubbor, around it~
periphery. The seal make~ Qliding engagement with the pipe
inner surfàce to be l~ned. This arrangement ensures that no
fouling of other mechanical parts of the applicator with com-
position occur~, and also provide~ some final cleaning of the
inner ~urface of the pipe by its sliding action, immediately
prior to composition application.
Suitably, the flowable composition comprise~ a ter-
minally reactiv~ diolefin polymer, curable to a rubbery con-
position, and a curative for the diolefin polymer, the co~-
po~ition having a vi~co~ity below about 1,000,000 cps. The
terminally reactive diolefin polymer is proferably a liquid
polymer o~ butadiene, said polymor having terminal allylic
halidQ group~, and the curativ i~ preferably a polya d ne. Such
a terminally reactiv diolefin polyo~r may suitably be mlxed
with a rubb ry thermop}astic polymer, a thixotropic materlal
and a solv-nt for the thermopla~tic polymer, the amount of
solvant being ~ufficient to mai~tain the vi~co~ity of the
compo~itlon below about 1,000,000 cp~., and preferably from
about 750,000 to about 500,000 cp~.
The mo~t preferred t rminally reactive diolefin poiymer
i~ a liquid polymer of butad~ene having terminal allylic bromide
group~, in an a~cunt of, on avorage, more than one and prefor-
ably about two reactive group per molecule. Such materials
are available on the market, and in conjunction with suitable
curing agent~, cure to rubbery re~ilient compo~itions at room
temperature. A~ alternatives to tenminally brominated butadiene
polymer~, there may be mentioned liquid polymers of butadiene
or isoprene having terminal reactive group~ ~uch a~ hydroxyl or
- 4
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carboxyl groups
The rubbery thexmoplastic polymers which can be u~ed
in these compositions are polymers having satisfactory rubber-
like properties at room temperature and which, at elevated -
temperature, can be processed as typical thermoplastic xesins
Such polymers include ethylene-vinyl acetate copolymers,
ethylene-ethyl ~crylate copolymers, and block copolymers of the
A(BA) type whore A is a resinous polymeric block e g poly-
ethylene or polypropylone or i8 a mono-alkenyl aromatic hydro-
carbon polymer, ~uch as a styrene polymer or a-methyl styrene
polymer, and B iB an elastomeric block e g an ethylene-propylene
copolymer or a conjugated diolefin polymer, ~uch as a butadleno
polymer, or an ~opr-n polymer ~he rubbery th-rmoplastic
polym-r nhances the ~tr ngth of the final cur d compositlon
Pr-f-rred among tho thermoplaatic rubbery poly~ers are block co-
poly~ r~ of tho typ- A(BA)n type where A i8 a monoalk nyl aro-
m tlc hydrocarbon polymer block, B i8 a conjugated diolefin
polymer block, and n is an int ger from 1 to 4
The proferred compositions conta~n a thixotropic
ma~erisl This mat-rial s-rves to give the composit~on suf-
f~ci-nt body that it will ma~ntain its position when applied -
- ~t r duce- slump in the lining before the lining has cured -
and y t it oxhibits a decrease in viscosîty ao applied shear
~ ncreased Suitable thixotropic material is the very fine
particle size si1ica, an example of which is Cab-0-Sil (Trademark
of Cabot Corporation) The particle size of ~uitable silica i~
; from about 70 to about 500 Angstroms
In addition, the preferred compositions according
to the invention contain an organic solvent for the block
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1~3~44
copolymer, in an amount to maintain the viscosity of the
composition below about 1,000,000 cps., preferably of from
about 750,000 Cp8. to about 500,000 cps. Suitably, the solvent
is toluene, benzene, cyclohexane or mixtures of two or more of
these. In the process of the invention, the solvent largely
evaporates from the composition on curing, and is collected and
re-used.
The preferred compositions may contain a naphthenic oil.
Suitable naphthenic oils meet the ASTM D2226 Type 103 designa-
tion and can have a range of viscosities. Aromatic orparaffinic oils are not suitable. An example of a suitable oil
i8 Sunthene 422 (Trademark of Sun Oil Company).
The compositions used in the present invention may
include a reinforcing filler, to enhance the tensile strength
and abra~ion re~istance of the final cured rubbery composition.
8ultable fillers are the carbon black~. The composition~ may
optionally also include a bituminous ~ubstance such a~ a~phalt
or coal tar, which provide~ body to the compo~ition, and as~ist~
; in providin~ adhesion of the composition to the inner pipe
~urface~ to be lined.
It is necessary to include a curative for the
terminally reactLve diolefin polymer in the compositions prior
to their application. The type of curative used depend~ on the
type of reactive group pre~ent in the polymer. It is a poly-
functional curative, Quch as a polyepoxide, polyi~ocyanate or
~! polyamine which i5 capable of reacting with terminal groups in
the polymer and forming a cured structure. In the case of the
preferred polymer of butadiene having terminal allylic bromide
group~, the curative is a polyamine, preferably a poly (alkyl-
enimine) containing more than five amine nitrogen atoms per
i
l molecule.
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The relative portions of ingredients in the flowable
compositions used in the present invention can vary over fairly
wide limlts. Suitably, for 100 parts by weight of terminally
reactive pol~mer, there will be included from about 50 to about
300 parts by weight, preferably from about 200 to about 300
parts by weight, of the rubbery thermoplastic polymer, from
about 2 to about 20 parts by weight, preferably from about 5 to
about 10 parts by weight, of the curative for the terminally
reactive polymer, from about 10 to about 60 parts by weight of
thixotropic material, preferably from 30 to 50 parts by weight,
and from 0 to 100 parts by weight, preferably about 20 to about
40 parts by weight, of naphthenic oil, from 0 to about 100
parts by weight of asphalt, from 0 to about 60 parts by weight
of carbon black reinforcing filler, and from about 100 to about
400 parts by weight, preferably from 150 to 300 parts by weight,
of organic solvent.
The cured rubber linings obtained from these liquid
compositions have the necessary resilience, tensile strength and
abrasion resistance to withstand the transportation of abrasive
~lurries and corrosive materials for extended periods of time.
They are relatively simple and easy to apply by the process of
the present invention, and cure in situ without special treat-
ment or heating, to provide the desirable rubber linings.
A specific embodiment of an apparatus and proces~
according to the present invention is illustrated in the
accompanying draw:ngs in which:
FIGURE 1 is a diagrammatic side view, partly in section
of one form of apparatus for lining a straight pipe section;
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FIGURE 2 is a diagrammatic plan view partly in section,
of an apparatus for lining a curved pipe section, or "elbow",
of constant curvature.
FIGURE 3 is a diagrammatic side sectional view of a
portion of an alternative apparatus for use in place of that
shown in Fig. 1.
In the drawings, like reference numerals indicate
like parts.
With reference to Fig. 1 a steel pipe section 10 of
cylindrical form to be provided with an elastomeric lining is
mounted securely on a work table 11 by means of clamps 12, 13.
Within the pipe 10 is located an axially movable applicator,
generally designated 14. The applicator comprises a forward
member 15 in the form of a plate, a frusto-conical rearward
member 16 attached to the forward member 15 by means of rods 17,
18, and an elongated metal tube 19 for supplying the flowable
composltion. The rearward member 16 is disposed rearwardly of
the forward member 15 80 as to leave a space 20 therebetween.
The end of the tube 19 opens into the space 20, for the supplying
of the compo~ition to the space 20.
Tube 19 extends beyond the forward end of the pipe
section 10, and is slideably received and supported in a
bearing 21 mounted on a pedestal on the table 11, beyond the
forward end of the pipe section 10. The forward end of tube 19
is connected via flexible supply tubing 23 to a source of supply
of flowable lining composition ~not shown).
Tube 19, which is secured to forward member 15 of
applicator 14, is provided with a depending bracket 24 near the
rearward end thereof. This is connected to a flexible drive
cable 25 which connects via sheave 26 in the pede~tal
A
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1043~4
and sheave 27 to motorized winch 28 mounted on a lower level
o~ table 11 Winch 28 thus serves to pull applicator 14
ax~ally forwardly through pipe section 10
The forward member 15 of applicator 14 is in the
form of a plate It is provlded at its periphery with an
annular sliding ~eal 2g mounted in a peripheral recess in
~ember lS, and made o~ hard resilient material ~u~h as hard
rubber Ihe applicator 14 i5 arr~nged 80 that seal 15 fit~
~nugly with n plpe soction 10 80 as to ~ake a smooth sl~ding
~eal ~th the ~lde plpe ~urface to be l~ned
The r-arward member 16 of appllcator 14 presents a
frusto-conlcal urface 30, converging in the forward direct~on,
to the ~slde plpe ~urface m e tra~ g dge 31 define~ a
p rlph~ral gap 32 of pr-determined size b tw n ~t and the
~nslde pipè ~urface, and acts as a ~pr--a~ng ~dge for appll- !
cation o th co~pos~t~on
~n operatlon, floxlble tube 23 ~8 connected to a
~ource of ~upply of c~rable flowable co~po itlon, plpe sectlon
10 i8 cl-~ped to work table 11, applicator 14 ~8 placed inside
th pipe ~-ctlon 10 at the extrome left-hand nd, tube 19 1~
~ount~d in b~ar~ng 21, and flexible drive cable 25 i8 connccted
to w~ch 28 Supply of flowable co~po~ition i8 commenced,
und allowod to co~tinue until 8paCe 20 i8 ub~tantially filled
. , .
with compo~ition, whereupon winch 28 i~ 6tarted up 80 that
applicator 1~ i8 drawn forwardly through the pipe ~ection 10
.
The ~upply of materlal to ~pace 20 is regulated in conjunction
;~ with the speed of travel 80 as to ~aintain space 20 sub~taA-
tially full of composition to be applied As appllcator 14
moves axially with~n the pipe ~ection 10, compo6ition is~ue6
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1(~43~-~44
through gap 32, and i8 effectively ~pread by trailing edge
31 of rearward member 16 on the inner ~urface of the pipe section
10, to a thickne~s corresponding to the predetermined width of
the gap 32. Forward member 15, which precedes rearward member
16 in this travel provides a degree of cleaning of the inside
~urface of the pipe section immediately prior to applicat~on
of lining composition, as well as providang a seal to prevent
i~sue of ~aterial forwardly of plate 15. When the applicator
14 reaches the forward end of pipe section 10, 80 that sub-
~tantially the entire inside pipe surface i8 lined with com-
po~ition, the ~upply of composition to tube 23 is ~hut off,
winch 28 is stopped and the applicator 14 is removed from the
pipe ~ection 10. Then the pipe section 10 is left 80 that the
¢oqpo~ition can cure, to form an elastomeric lin~ng on the insido
~urace thereof.
With roforence to Fig. 2, there is provided a work
Wbl~ 33, on tho top surface of which is pivotally mounted at
34 a ~ector plate 35. The sector plate 35 is ~Npported on
ball rollers 36, 37, 38 for pivotal movement relative to the
table 33 about p~vot 34. A pipe elbow 39 of con~tant curvature,
to be lined, i~ clamped to the sector plate 35 by means of
relea-able clamps 40, 41. The elbow 39 is 6upported 80 that it~
centxe of curvature coincides with that of the sector plate 35.
The sector plate 35 carrying the elbow 39 is adapted to be
; rotated about pivot 34 by,means of motorized winch generally
de~ignated 42 and cable 43 attached to point "Xn, 80 that sector
plate 35 travels from the position shown in f~ll line~ in Fig. 2
to the position 8hOWn in broken lines in Fig. 2.
Di~po~ed witbin pipe elbow 39 is an applicator
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gener~lly designated 14, and ~imilar in mo~t respect to the
applicator described with respect to Fig. 1. ThUS it comprises
forward member 15 in the form of a plate, a rearward member 16
of generally ~rusto-conical form, rods 17, 18 connecting forward
member 15 to rearward member 16, and an elongated rigid metal
tube 19 for ~upplying liquid material to space 20 between the
forward and rearward members. The forward member 15 and rear-
ward member 16 are angularly displaced relative to one another,
rods 17 and 18 being of different length~, and tube 19 i8 curved,
~o that the applicator 14 as a whole has a radiu~ of curvature
~ub~tantially coinciding with that of pipe elbow 39, and a
centre of curvature located at pivot 34.
At its forward end, beyond the end of pipe elbow 39
Jnd ~ector plate 35, tube 19 is mounted on a pede~tal 22 on the
worX table 33. It is connected to a source of ~upply of flow-
able co~po~ition.
The operation of the apparatus of Fig. 2 in conduct~ng
the proco~ of the invention i~ similar to that of Fig. 1,
xcopt that in this ca~e the applicator 14 i8 kept stationary
while ~ector plate 35 and pipe elbow 39 move, about pivot 34.
Flowable composition is ~upplied to space 20 and ~pread on
the inner pipe elbow ~urface by frusto-conical rearward member
16, in the manner previously described. The rate of ~upply of
flowable composition to space 20 i~ regulated in accordance
with the speed of angular movement of pipe elbow 39, so as to
keep space 20 substantially full of lining material. When
sector plate 35 and pipe elbow 39 reach the limit of their
angular travel, indicated by broken lines in Fig. 2, applicator
14 has moved ~ubstantially completely through pipe elbow 39 ~o
- ` ~.o~a3~4
as to complete the lining thereof. Supply of flowable com-
position is shut off, and the lining is allowed to cure ir.
situ on the pipe.
It will be appreciated that the thickness of lining
applied is determined by the size of the gap 32 between the
e~ge of rearward member 16 and the inner pipe surface. The
gap ~ize can thus be changed by replacing rearward plate member
16 by another ~uch member of different ~ize or different frusto-
conical angle, or by adjusting the frusto-conical angle on a
givon rearward member.
Fig. 3 shows an alternative form of applicator to
that illustrated in Fig. 1. In Fig. 3, the forward member 15a,
whil~t ~till of plate-like form, leaves a ~mall peripheral gap
44 between it~elf and the innor ~urface of the pipe 10 to be
coat-d. Flowable composition 45 is delivered by tube l9a to
~pac- 20a between forward member 15a and rearward member 16a,
~nd can flow forwardly of forward member 15a through gap 44,
- as ~hown at 46, if sufficient pressure exists in ~pace 20a.
Gap 44 iB ~maller than peripheral gap 32 between rearward
m-~ber 16a and the inner ~urface of pipe 10 to be coated. As
noted, this arrangement allows fluctuations in the flow rate
of comp~sition to 6pace 20a, with consequent variations in
pres~ure in space 20a, to be tolerated without adversely affec-
ting the evenness of the coating applied.
The form of rearward member 16a i8 also changed
slightly from that shown in Fig. 1. The frusto-conical surface
30a is reduced in size, and an extended cylindrical outer surface
47 i8 provided, defining the peripheral gap 32 which control6
the coating thickness.
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10~ 44
Location and support of the applicator in Fig. 3
within the pipe 10 is arranged by the provision of a sup-
porting wheeled structure 48 secured to pipe tube l9a within
pipe 10, and located forwardly of forward member l5a. Sup- - -
portang structure 44 is provided with arms 49, 50 carrying
wheel~ 51, 52, 53, 54 at each end thereof. Arm~ 49, 50 are
pivotally mounted on the structure 48, and are adjustable
relstive thereto 80 as to arrange for wheels 51, 52, 53, 54
to bear upon the inner pipe ~urface and support the tube l9a
~nd the ~pplicator connected thereto w~thin pipe 10 80 that
it can be ~oved axially within the pipe.
A ~milar form of applicator to that shown in Fig.
3 c~n be u~ed to 1 ne pipe elbows, ~n the mannor shown ln
Flg. 2. Thu~, the forward ~e~ber 15 of the appl~cator sbown
ln Fig. 2 can be roplacoa by one of orm ~llu-trated at l5a
ln Fig. 3. S~milarly, corr-~ponding roarward member 16a can
be ~ub~tltuted, and a ~upporting structure like that shown at
48 in Fig. 3, ~ncludod ~n the Fig. 2 apparatu~.
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