U.S. patent application number 11/969329 was filed with the patent office on 2008-07-24 for expandable skin for restructuring an inner lining.
Invention is credited to Yves Charron, Nicolas Gautreau.
Application Number | 20080173059 11/969329 |
Document ID | / |
Family ID | 38330199 |
Filed Date | 2008-07-24 |
United States Patent
Application |
20080173059 |
Kind Code |
A1 |
Gautreau; Nicolas ; et
al. |
July 24, 2008 |
Expandable Skin for Restructuring an Inner Lining
Abstract
A skin and a method for restructuring the inner surface of a
tube of long length includes manufacturing a skin, in a material
with expansion rate greater than 50%, the external surface of which
includes a restructuring print determined in order to take into
account the longitudinal and radial expansions that the skin is
going to undergo, and as a function of the desired final surface
state for the tube to be restructured, longitudinally expanding the
skin up to the required length for the tube, longitudinally
introducing expanded skin inside tube to be restructured, and
radially expanding the skin to realize the restructuring.
Inventors: |
Gautreau; Nicolas;
(Montesson, FR) ; Charron; Yves;
(Longpont-Sur-Orge, FR) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
38330199 |
Appl. No.: |
11/969329 |
Filed: |
January 4, 2008 |
Current U.S.
Class: |
72/367.1 |
Current CPC
Class: |
F16L 55/1645 20130101;
B05D 1/40 20130101; B05D 5/00 20130101; B05D 7/222 20130101 |
Class at
Publication: |
72/367.1 |
International
Class: |
B21D 3/00 20060101
B21D003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 5, 2007 |
FR |
07/00.087 |
Claims
1. Method for restructuring the inner surface (3) of a tube (2) of
long length that comprises the steps of: manufacturing a skin (1),
in a material with expansion rate greater than 50%, which external
surface includes a restructuring print determined in order to take
into account the longitudinal and radial expansions that the skin
is going to undergo, and as a function of the desired final surface
state for the tube to be restructured; longitudinally expanding the
skin up to the required length for the tube; longitudinally
introducing expanded skin (1') inside tube (2) to be restructured
radially expanding skin (1'') to realize the restructuring.
2. Restructuring method according to claim 1, wherein the radial
expansion is done by putting the skin under pressure.
3. Restructuring method according to claim 2, wherein the skin
withdrawal and skinning is done by reducing the pressure.
4. Restructuring method according to claim 1, wherein the skin
withdrawal and skinning is done by decreasing the axial
expansion.
5. Restructuring method according to claim 1, wherein the rate of
expansion of the skin material is greater than 100%.
6. Restructuring method according to claim 5, wherein the rate of
expansion of the skin material is greater than 300%.
7. Restructuring method according to claim 6, wherein the rate of
expansion of the skin material is greater than 600%.
8. Restructuring method according to claim 1, wherein an inner
lining is introduced inside the tube before introducing the
skin.
9. Restructuring method according to claim 1, wherein the surface
state required for the skin after extension is ultra smooth and
permits to define, through longitudinal and radial extensions
exerted on the skin, the surface state of the skin before
extension.
10. Restructuring method according to claim 1, wherein the surface
state required for the skin after extension is a bi- or
tri-dimensionally structured surface state, and permits to define,
with the longitudinal and radial extensions to be exerted on the
skin, the surface state of the skin before extension.
11. Restructuring method of the surface of a tube inner lining
according to claim 1, wherein the tube constitutes a duct for gas
or fluid transport.
12. Longitudinally expandable skin in a material with an expansion
rate greater than 50%, for restructuring the surface of a tube
inner lining forming a duct for gas or fluid transport, whose
external surface includes a restructuring print determined in order
to take into account the longitudinal and radial extensions that
the skin is going to undergo, and according to the desired final
surface state for the tube to be restructured.
13. Skin according to claim 12, wherein the skin material is
silicone-based.
14. Skin according to claim 12, wherein the skin external surface
presents a state of ultra-smooth surface.
15. Skin according to claim 12, wherein the skin external surface
presents a structured bi- or tri-dimensional surface state.
Description
SUMMARY OF THE INVENTION TECHNICAL CONTENT
[0001] The invention concerns a method for restructuring the inner
surface (3) of a long length tube (2) that comprises the steps of
[0002] Manufacturing a restructuring skin (1) in a material with an
expansion rate greater than 50%, [0003] Longitudinally expanding
the skin up to the length required for the tube; [0004] Introducing
longitudinally expanded skin (1') inside tube (2) to be
restructured [0005] Radially expanding skin (1'') to do the
restructuring. The invention also concerns a longitudinally
expandable skin for restructuring the surface of a tube inner
lining forming a duct for gas or fluid transport.
[0006] 1. Technical Domain of the Invention
[0007] The invention concerns the restructuring of a tube inner
lining surface, notably of a pipeline constituting a duct for gas
or fluid transport, by means of restructuring skins.
[0008] 2. Anterior Art
[0009] In the following description the meaning of "restructuring a
surface" is [0010] the ultra smoothing of a surface having the
property to reduce the aerodynamic drag of a wall with regards to a
rough surface, [0011] structuring a surface: conventional
structured surfaces are presented with groove shapes aligned in the
direction of the flow. Their property, among others, is to reduce,
with regards to a smooth surface, the aerodynamic drag along a
wall. This property results from an attenuation, in the direction
transverse to the flow, of speed fluctuations and, therefore, of
the corresponding turbulence component.
[0012] The structured surfaces can be bi-dimensional or
tri-dimensional.
[0013] Bi-dimensional structures present a constant height in the
flow direction, their dimensions only varying in the transverse
direction. The bi-dimensional structures of the anterior art
(usually called "riblets": "small rib") can present some
a--triangular, b--semi circular, c--trapezoidal, and d--knife blade
shapes.
[0014] The tri-dimensional surfaces may be represented, i.e. by
segments of disks in the flow direction (Bechert, 1987), shapes
obeying a fractal distribution (U.S. Pat. No. 4,650,138 and U.S.
Pat. No. 4,759,516) or herringbone structures (EP 0 543 647
A1).
[0015] "Restructuring skin" is meant as an elastic balloon (an
enclosed wall) or membrane (an open wall), increasing in volume
under the effect of pressure, and capable to line the shape of the
object to be restructured.
[0016] The objective of the restructuring surface is to modify the
surface state, in order to obtain, [0017] either ultra-smooth
surfaces; [0018] or structured surfaces.
[0019] The surface state modification provides a reduction in load
loss, advantageous in the case of tube inner linings forming a gas
or fluid duct. The ultra-smoothness, on the other hand, allows for
reducing friction coefficient, salts and paraffin deposit in
production tubes, the number of interstices and holes resulting
from a material deposit with insufficient material thickness.
[0020] Patent FR 2.879.948 describes a device and method for
realizing restructured surfaces in ducts, in order to reduce the
aerodynamic drag by means of a restructuring skin whose external
surface is smooth or include patternings.
[0021] A means was sought-after to apply a skin for restructuring
an inner lining surface in large size tubes constituting a duct,
i.e. for gas or fluid transport, in order to reduce load losses
within said duct. However manufacturing such membranes for
placement of restructuring skins into tube inner linings pose many
problems due to their sometimes complex shape (namely in case of
double-cone skins), but also to their large size, and to the
restructuring indentation that must conform to the structured or
ultra smooth surface state required for the lining. Indeed, in case
of, i.e. gas transport tubes, they are about 12 m long, therefore
[0022] manufacturing a very long skin requires complex and very
expensive tooling, notably with regard to mould size; [0023] in
order to have a beam mounted cantilever to support a very long skin
requires a complex (stepped diameter), voluminous, heavy beam shape
counterbalanced with a weight of momentum equivalent to that
exerted by the beam.
DESCRIPTION OF THE INVENTION
[0024] This invention proposes to apply a longitudinally expandable
skin for restructuring the inner lining surface in large size
tubes.
SUMMARY
[0025] The invention concerns a method for restructuring the inner
surface (3) of a tube (2) of long length that comprises the steps
of [0026] manufacturing a restructuring skin (1) in a material with
an expansion rate greater than 50%, [0027] longitudinally expanding
the skin up to the required length for the tube; [0028] introducing
longitudinally expanded skin (1') inside tube (2) to be
restructured [0029] radially expanding skin (1'') to do the
restructuring.
[0030] Preferably, the radial expansion is provided by putting the
skin under pressure.
[0031] The skin withdrawal and skinning can done by reducing the
pressure.
[0032] The skin withdrawal and skinning can done by decreasing the
radial expansion.
[0033] Preferably, the rate of expansion of the skin material is
greater than 100%, in a more preferred way 300%, and in an even
more preferred way greater than 600%.
[0034] In one form of embodiment, an inner lining is introduced
inside the tube before introducing the skin.
[0035] Advantageously, the state of the skin surface before
expansion is defined as a function of the longitudinal and radial
expansions that will be exerted on the skin, and of the required
surface state of the skin after expansion. In one form of
embodiment, the required surface state is ultra smooth. In another
form of embodiment, the required surface state is a bi- or
tri-dimensionally structured surface state.
[0036] Preferably, the tube forms a duct for gas or fluid
transport.
[0037] The invention also concerns a longitudinally expandable skin
for restructuring the surface of a tube inner lining forming a duct
for gas or fluid transport. Preferably, the skin material has a
rate of expansion greater than 50%.
[0038] Advantageously, the skin material is silicone-based.
[0039] In one form of embodiment, the skin external surface
presents a state of ultra-smooth surface.
[0040] In another form of embodiment, the skin external surface
presents a bi- or tri-dimensionally structured surface state.
DETAILED DESCRIPTION OF THE INVENTION
[0041] FIGS. 1a, 1b, 1c, 1d, 1e represent several steps of the
inner lining restructuring method of a tube by means of an
expandable restructuring skin according to the invention.
[0042] FIG. 1a: Cross-section view of the restructuring skin before
longitudinal expansion and internal pressurization (initial state
1).
[0043] FIG. 1b: Cross-section view of the restructuring skin
expanded longitudinally (longitudinally expanded state 1').
[0044] FIG. 1c: Cross-section view of a tube during the application
of an inner lining (deposit by spray, injection, chalking, dip
coating . . . ).
[0045] FIG. 1d: Cross-section view of the tube to be internally
restructured, equipped with the longitudinally expanded skin
according to the invention.
[0046] FIG. 1e: Cross-section view of the tube equipped with the
skin inflated and under pressure (longitudinally expanded, radially
expanded, and pressurized state 1'').
DESCRIPTION OF THE FIGURES
[0047] FIGS. 1a to 1e describe, in a non restrictive manner, a
method of restructuring an inner lining surface of large size tubes
by means of a restructuring skin according to the invention that
consists of the following steps: [0048] a) Manufacturing a
restructuring skin (1) which surface state is, in the initial
state, defined according to the longitudinal expansion that will be
exerted on the skin, and the required final surface state of the
longitudinally expanded skin (FIG. 1a). The manufacture is done
using any means known of the skilled man, i.e. in a mould for
silicone skin, and by stripping using various processes, such as:
lubricant, lost-wax, disassembling mold made of several parts.
[0049] b) Longitudinal expansion of the skin according to the
required restructuring length of the tube: expanded skin (1') (FIG.
1b). [0050] c) Possible introduction of a cold-dropped lining (3)
in the tube to be restructured (2): epoxydic bases with solvent
(phenolic), in aqueous phase, or without solvent, polyurethane
bases, PVC, or hot-dropped: Polyamide, epoxy, or PVC, inside the
tube, if the tube is not already lined with a structurable internal
lining (FIG. 1c). [0051] d) Setting the skin (1') inside the tube
to be restructured and attaching centering supports (4) externally
to the tube (FIG. 1d). [0052] e) Inflating and putting the skin
under pressure by means of a valve (5) or radial expansion by any
other means known of the skilled man, in order to realize the step
of restructuring of the inner lining (FIG. 1e): longitudinally
extended and radially expanded skin (1''). [0053] f) Deflating, or
withdrawing and skinning of the skin by successive and/or
simultaneous actions of pressure reduction and axial expansion.
[0054] g) Dissociating the external supports and withdrawal of the
skin.
[0055] The means of radial expansion may be i.e. brought on a
shaft, which longitudinal displacement along the tube main axis
permits the application of the extended skin over the whole length
of the tube. The means of radial expansion may be a toric form
elastic assembly in order to possibly apply a more regular pressure
over an inner circumference of the duct, i.e. a ring-shaped
chamber, pressurized or in a flexible material, that is displaced
by sliding along the inner surface of the skin. A set of cushions,
or wheels, arranged in a circumference, and including means of
applying a radial pressure force, either mechanical or pneumatic,
onto the skin, may also be considered. Any other means known of the
skilled man may also be appropriate.
[0056] The material constituting the skin may be any product or
material with good replica properties, a low adhesion, and a strong
rate of expansion. A strong rate of expansion means a rate of
expansion of about 50%; preferably of about 100%, very preferably
of about 300%; and even more preferably of about 600%.
[0057] As examples of products that may be used for the skin
membrane, notably elastomers with a strong rate of expansion may be
mentioned, such as rubber, silicones, or KRATON.TM. type of
materials, alone or in mixture.
[0058] Some silicones have a rate of expansion greater than 600%.
The preferred material for the skin is silicone-based.
[0059] The skin membrane may include reinforcement materials to
provide improved membrane resistance during longitudinal
extension.
[0060] The method according to the invention may be used for
restructuring inner tubes including cold-dropped liners, such as:
epoxydic bases with solvent (phenolic), in aqueous phase, or
without solvent, polyurethane bases, PVC.
[0061] The method according to the invention may also be used for
restructuring hot-dropped linings, such as polyamide, epoxy or PVC
types.
[0062] This membrane presents appreciably the same roughness at
that of the mold considering a replica capacity (wetability) of
material in liquid phase greater than the mould roughness fineness
(deformation height).
[0063] The mould is made with a surface state (lower roughness
height) greater than that of the inner linings applied in a
conventional way. The surface state is chosen at the upper limit of
the sensitivity threshold of the friction factor.
So the roughness: [0064] of an inner lining conventionally applied
is in the order of 10 to 20 .mu.m (average of 5 samples of the
surface distortion peak to peak interval: Ry5) [0065] of a primary
mold (glass, broken in steel . . . ) is in the order of 1 .mu.m
(Ry5) [0066] of the replica membrane surface (secondary mold) is in
the order of 1 .mu.m (Ry5) [0067] of the lining surface (tertiary
mold) replicated by the membrane is much less than that of the
membrane (secondary mold) [0068] sensitivity threshold of the
friction factor in the order of 1 .mu.m.
ADVANTAGES OF THE INVENTION
[0069] The interest of the method is to permit an easy installation
of skins for restructuring inner lining surfaces of long length
tubes, while maintaining a very good surface state. Indeed, in
addition to simplifying by using a skin size smaller than that of
the tube which contain the lining to restructure, skin withdrawal
is also facilitated [0070] Membrane skinning is facilitated by a
high longitudinal tension (high axial force). [0071] Membrane
skinning is facilitated by the alternated actions on membrane
depressurization and axial expansion reduction. From another point
of view, the method according to the invention provides high
quality surface states for the inner lining.
[0072] Indeed, the longitudinal and radial expansions produce a
decrease in height of the surface protrusions (roughness)
appreciably proportional to the product of longitudinal and radial
expansion rates.
[0073] Similarly, the longitudinal and radial expansions produce a
distance increase between the protrusions appreciably proportional
to the product of longitudinal and radial expansion rates.
With regard to roughness: [0074] physical roughness (measured by
roughness tester) is decreased appreciably in proportion to the
product of longitudinal and radial expansion rates; [0075]
hydraulic roughness (measured by friction factor) is decreased
appreciably in proportion to the product of longitudinal and radial
expansion rates;
* * * * *