The present invention relates to the repair or restoration of local cracks in pipes, in particular of large diameter water, fuel or gas underground pipelines. More specifically the invention concerns the repair of such pipes when the exact site to be repaired is either unknown or unreachable.
In order to conduct water, fuel or gas over large distances, pipelines that span immense lengths are installed. Occasionally, due to corrosion or other different wearing processes, small cracks might occur in the pipes, resulting in a leakage of the fluid that flows through the pipe. Since the pressure in such pipes may reach up to 100 at., the fluid is rapidly lost into the soil.
A leakage is usually discovered by a sharp pressure-drop, or by the recognition of a stain over the leakage location, indicating that a large amount of the fluid has already been lost. Besides the environment-harming aspect, such leakages may cause the loss of thousands of dollars per hour.
The repair of underground pipelines poses a series of complicated technological problems considering the relevant factors, mainly, difficult accessibility to the damaged part of the pipelines if welding or complete replacement thereof needs to be applied. This is particularly true when considering pipelines that are thousand of kilometers long or pipelines that lay underneath buildings and roads.
Also due to the high pressure prevailing in the pipeline, the use of simple adhesives and other common sealing agents had to be ruled-out.
The closest prior art known to applicants is Russian Patent No. 2063273 (Appln. No. 92007181/26 filed Nov. 23, 1992), describing a method of in-situ repair (namely from the inside of the pipe), by injecting specific chemical substances from both sides of the damaged location.
It is the prime object of the present invention to provide a more efficient method of in-situ repair of pipelines.
It is a further object of the invention that the actual repair process be completed instantly, reducing to a minimum the time period during which the flow through the pipeline must be discontinued.
It is a still further object of the invention to offer one or more sealing agents formulations especially suitable for the purposes the invention herein disclosed.
According to the invention there is provided a method of repairing leakage in pipelines comprising the steps of forming a first opening in the pipeline upstream of the leakage location, forming a second opening in the pipeline downstream of the leakage location, inserting through the first opening a first body, conforming the size of the pipeline, into the pipeline downstream of the first opening, filling the space arrear of the first body with a first viscose sealing material, inserting through the first opening a second body conforming the size of the pipeline into the pipeline arrear of the first viscose sealing material, compressing the first sealing material by applying a pressure against the first and the second bodies in opposite directions, causing the first body, the compressed first sealing material and the second body to move in unison in the direction of the second opening, and retrieving the first and second bodies from the pipeline through the second opening.
The method preferably comprises the further steps of filling the space arrear of the second body with a second viscose sealing material, inserting through the first opening a third body, conforming the size of the pipeline, into the pipeline arrear of the second viscose sealing material, compressing the first and second sealing materials by applying a pressure against the first and the third bodies in opposite directions, causing the first body, the compressed first sealing material, the second body, the compressed second sealing material, and the third body to move in unison in the direction of the second opening, and retrieving the first, second and third bodies from the pipeline through the second opening.
The said bodies are preferably spherical, made of a semi-rigid material such as Polyurethane.
These and additional constructional features and advantages of the present invention will become more readily understood in the light of the ensuing description of preferred embodiments thereof, given by way of example only, with reference to the accompanying drawings, wherein—
In
A leaking location L has been identified, typically due to a hole or a crack H caused by excessive corrosion developed over many years of use.
The first stage of the repairing method consists of shutting-off the flow in the pipe by the valve 12 and digging-away the ground over the pipe at two distanced locations A and B at both sides of the leaking location L. The distances A to L and B to L need not be equal, and in fact selected according to the accessibility conditions which may change from one site to another.
At each location A and B, the pipe is torch-cut so as to form a first circular opening 14a, and a second circular opening 14b, respectively, both of a diameter equal to that of the pipe 10. Up-rise pipe sections (“manholes”) 16a and 16b are welded or otherwise affixed to the pipe 10, as shown.
In the next stage (
It should be emphasized at this stage that the sealing method as proposed according to the present invention can be applied by using the spherical bodies C1 and C2 and a viscose sealing material M1 only, in the exact manner as will be described further below. However, it is highly preferable to use a combination of materials M1 and M2, which needs the introduction of a third spherical body C3, as depicted in
Whether or not the option of
To this end, pressure should be applied from both sides of the array C2-M1-C1 (or C3-M2-C2-M1-C1). For this purpose, as seen in
It is further requested that the pressure P1 applied from 16a be somewhat greater then that P2 applied from the opposite side, which pressure difference will cause the propagation of the array C3-M2-C2-M1-C1, in unison, in the direction of the manhole 16b.
The amount of pressure P2 that should be applied against the array is preferably given by the formula:
P2≧a−b/D
wherein:
P2—pressure (bar);
a—an empirical factor that varies between 2.5 and 3.5;
b—an empirical factor that varies between 0.035 and 0.045; and
D—diameter of the pipe (meters).
During the travel of the array, as shown in
In the further stage (
The pipe sections 16a and 16b are then removed and replaced by covers 18a and 18b of any conventional type (
According to a preferred embodiment of this invention (
The bags are preferably made of a readily tearable sheet material, such as cellophane or polyethylene, so that they become ruptured when pressure is applied to the array from both sides (
Let us now turn to the specification of the materials recommended according to an additional aspect of the present invention.
In an embodiment wherein only one sealing material M1 is employed, the material should be selected from the group of conventional hardeners.
In the preferred embodiment, according to which two materials M1 and M2 are used, the materials may consist of a mix of a compound A, a hardener B a softener S, a filler mineral Z, an elastic filler E and a hard filler D, wherein:
The proportional amount of each of the components regarding the respective materials is given below (in weight parts).
Material M1
100 units of component A, 0-10 units of component S, 110-130 units of component Z, and component B, the amount of which is given by the formula:
B=A*λ−K1
Wherein:
K1—an empirical factor that varies between 0 and 25; and
λ—an empirical factor that varies between 02-0.45.
Material M2
20-60 units of component A, 0-10 units of component S, 50-100 units of component Z and component B, the amount of which is given by the formula:
B=A*λ+K2
Wherein:
K2—an empirical factor that varies between 0 and 30; and
λ—an empirical factor that varies between 02-0.45.
Additionally, material M2 should contain 10-15 units of component E and 5-10 units of component D that are meant to penetrate the crack together with material M2 and create a partial barrier between the filling materials and the fluid upon restarting of the flow in the pipe, so that the filling will not become washed away.
The total amount of the sealing materials that should be injected between two adjacent spherical bodies is given by the formula:
G≧ρD
wherein:
G—quantity (tons);
ρ—an empirical factor that varies between 1 and 1.2; and
D—internal diameter of the pipe (meters).
The time that will take for the combination of the materials M1 and M2 to solidify is expected to follow the formula:
T≧γLD
Wherein:
T—time (hours);
γ—an empirical factor that varies between 2.5 and 15;
L—length of pipe (kilometers); and
D—internal diameter of the pipe (meters).
After that period of time it will be safe to renew the flow through the pipe without the danger of washing away the seal layer.
In order to achieve optimal results in regard to the solidification of the combination of these two materials, according to a preferable embodiment, the first material M1 should contain a certain amount of material M2, and the material M2 should contain a certain amount of material M1. This could be achieved either by simply mixing all the ingredients together or by using capsules that contain M1 and M2 and inserting them into the bags of M2 or M1, respectively, so that when material M1 is pushed into the crack, the capsules will break and release a preset quantity of the material M2.
While the invention as herein described includes numerous specifics it should be readily apprehended by those skilled in the art to which the invention pertains that the scope thereof should not be limited by such specifics but rather in and by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
180474 | Jan 2007 | IL | national |
Number | Name | Date | Kind |
---|---|---|---|
2804147 | Pistole | Aug 1957 | A |
3108012 | Curtis | Oct 1963 | A |
3137318 | Remo et al. | Jun 1964 | A |
3272894 | Roach | Sep 1966 | A |
3356777 | Barrett | Dec 1967 | A |
3472285 | Ginsburgh et al. | Oct 1969 | A |
3834422 | Larson | Sep 1974 | A |
3885521 | von Arx | May 1975 | A |
3894131 | Speech | Jul 1975 | A |
4216738 | Muta | Aug 1980 | A |
4306821 | Moore | Dec 1981 | A |
4397890 | Kinumoto et al. | Aug 1983 | A |
4430841 | Yamaguchi et al. | Feb 1984 | A |
4440194 | Kinumoto et al. | Apr 1984 | A |
4582551 | Parkes | Apr 1986 | A |
4656207 | Jabloner | Apr 1987 | A |
4692479 | Schneider | Sep 1987 | A |
4720884 | Ralls | Jan 1988 | A |
5230842 | Munde | Jul 1993 | A |
5372162 | Frey | Dec 1994 | A |
5447664 | Ito et al. | Sep 1995 | A |
5599856 | Gardner | Feb 1997 | A |
5609186 | Satake et al. | Mar 1997 | A |
5853629 | Toyoda et al. | Dec 1998 | A |
5983948 | Yagi et al. | Nov 1999 | A |
5993581 | Toyoda et al. | Nov 1999 | A |
6057378 | Perstnev et al. | May 2000 | A |
6161588 | Bellamy et al. | Dec 2000 | A |
7127902 | Levy | Oct 2006 | B1 |
8015998 | Harris | Sep 2011 | B2 |
20050288395 | Simon | Dec 2005 | A1 |
20060084727 | Yan | Apr 2006 | A1 |
20080068922 | Voss | Mar 2008 | A1 |
20080144426 | Janssen | Jun 2008 | A1 |
20120067447 | Ryan | Mar 2012 | A1 |
Number | Date | Country |
---|---|---|
0 593 264 | Apr 1994 | EP |
0 713 048 | May 1996 | EP |
2 261 486 | May 1993 | GB |
2063273 | Jul 1996 | RU |
Entry |
---|
International Search Report mailed May 16, 2008 in PCT/IL2007/001633. |
Number | Date | Country | |
---|---|---|---|
20140311605 A1 | Oct 2014 | US |
Number | Date | Country | |
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Parent | 12521781 | US | |
Child | 14256486 | US |