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(11) | EP 4 477 805 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A METHOD FOR UNIFORM LINING OF A MANHOLE AND A MANHOLE LINING ARRANGEMENT |
| (57) The invention relates to a method for uniform lining of a manhole (2). The method
comprising: (A) preparing the manhole (2) for lining by clearing the manhole (2);
(B) measuring the depth (x1) and diameter (d1) of the manhole (2); (C) taking into
use a tubular liner (10) having a determined diameter (d2) based on the diameter (d1)
measured in step (8) and cutting the liner (10) to a determined length (x2) based
on the depth (x1) measured in step (8); (D) closing a first end (11) of the liner
(10); (E) impregnating the liner with (10) a hardening agent; (F) securing the impregnated
liner (10) to a plug cover (20) such that the plug cover (20) closes a second end
(12) of the liner (10); (G) Introducing the impregnated liner (10) to the manhole
(2) with a hoisting apparatus (3), such that the first end (11) of the liner (10)
reaches contact with bottom of the manhole (3); (H) introducing pressure medium into
the liner (10) via the plug cover (20) to force the liner (10) to expand against the
inner surfaces of the manhole (2); and (I) accelerating hardening of the hardening
agent with acceleration medium. The method also relates to a manhole lining arrangement
(1).
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0001] This invention relates to a method for uniform lining of a manhole, and particularly to a solution used for rehabilitating a deteriorated manhole in order to extend the life span of the manhole. The invention also relates to a manhole lining arrangement with which the manhole may be lined.
DESCRIPTION OF PRIOR ART
[0002] Manholes are widely used in plumbing, water collection, and general municipal water infrastructure. Manholes are not standardized but often include a bottom part, a conical upper part, and side walls extending between the bottom part and the conical upper part and are generally made of concrete. The life span of these manholes is estimated to be 40 to 60 years, as the materials begin to deteriorate with time. At this point the risks of water and leak damages begin to increase, and it is advisable to rehabilitate the manhole before any major damages occur on large scale. Well timed rehabilitation significantly reduces upkeep costs of the manhole as ballooning maintenance and reparation costs are avoided.
[0003] Traditionally, the deteriorated manhole is dealt with by replacing the manhole with a new manhole. In practice, the replacement is performed by excavating around the deteriorated manhole in order to remove it from the ground. The removed manhole is then replaced with a corresponding new manhole. This process is very ineffective in terms of time and costs but results in a manhole that is practically new. However, as the replacing requires the water connected to the manhole to be held back while the work is in progress, the slow process will halt the surrounding piping system connected to the manhole for the duration of the project. This causes a major inconvenience to the surrounding structures. Excavation is also difficult in colder climates when the ground is frozen, rendering it usable only during parts of the year when the ground is unfrozen.
[0004] There are also known non-excavating methods, which greatly reduce the rehabilitation time and the rehabilitation costs of the project as excavation is not required. One major problem in non-excavating methods is that the manholes have varying geometries, which must be considered, as the manhole rehabilitated instead of being replaced. Manholes may differ in depths, diameters, and cross sections, for instance.
[0005] One known non-excavating method is gunning of concrete. In this solution, a deteriorated manhole is gunned with one or more layers of concrete until a new inner surface having a thickness ranging from 20 to 70 mm is formed on the manhole. This requires the manhole to be first thoroughly cleaned, the loose debris to be removed from the manhole, and existing leaks in the manhole to be individually sealed. Gunning of concrete essentially creates a new concrete surface for the manhole that is estimated to have a life span of 50 years. This solution requires waiting for the concrete to cure which may take time if the curing conditions are not optimal and the solution requires substantial manual labor in tight spaces underground making it not worker friendly or time efficient.
[0006] Another known non-excavating method is lining of the manhole. In this known method a tubular liner is used to line the side walls between the bottom part and the conical upper part of the manhole. The bottom part and the conical upper part are then laminated by hand after the lining. This solution also requires manual labor when laminating the bottom and upper parts of the manhole and increases the possibility of leaks in the parts where the liner joins the laminated parts. Lining essentially creates a new surface coating for the manhole that is estimated to have a lifespan of 50 years.
[0007] All known manhole rehabilitation solutions each have significant drawbacks in one or more areas in terms of time efficiency, and cost efficiency, and quality of the rehabilitated manhole, for instance.
[0008] Therefore, there exists a clear need for an improved method for rehabilitating a deteriorated manhole.
SUMMARY OF THE INVENTION
[0009] An object of the present invention is to solve the above-mentioned disadvantages and to provide a method for lining a vertical manhole which is improved in terms of time efficiency, and cost efficiency, and the method further results in improved quality of sealing of the rehabilitated manhole. These and other objects are achieved with a method for uniform lining of a manhole according to independent claim 1 and with a manhole lining arrangement according to independent claim 9.
[0011] Further advantages and details of the invention are disclosed in detail in the description below.
BRIEF DESCRIPTION OF DRAWINGS
[0012] In the following the present invention will be described in greater detail by way of example and with reference to the attached drawings, in which
figure 1 illustrates a schematic side view of an embodiment of the invention at one stage,
figure 2 illustrates a schematic side view of the embodiment of figure 1 at a second stage,
figure 3 illustrates a schematic side view of the embodiment of figure 1 at a third stage,
figure 4 illustrates a schematic side view of the embodiment of figure 1 at a fourth stage, and
figure 5 illustrates a flow chart of an example method for uniform lining of a manhole.
DESCRIPTION OF AT LEAST ONE EMBODIMENT
[0013] The following embodiments are only examples. Although the specification may refer to "an" embodiment in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may contain also features/structures that have not been specifically mentioned. All combinations of the embodiments are considered possible if their combination does not lead to structural or logical contradiction.
[0014] Figures 1 to 4 are highly schematic illustrations of an embodiment of a lining arrangement 1 according to the invention at different stages of an embodiment method according to the invention. Figure 5 illustrates a flow chart of an embodiment of a uniform lining method for a manhole. This method may be implemented with the manhole lining arrangement 1 illustrated in figures 1 to 4.
[0015] The embodiment method of figure 5 for uniform lining of a manhole 2 comprises the following steps A to I.
[0016] A preparing the manhole 2 for lining by clearing the manhole 2. This clearing ensures that a liner 10 is able to reach contact with the inner surfaces of the manhole. This clearing may include removing all debris and interfering structures such as ladders from the manhole 2, for instance. The manhole may further be cleaned to ensure that the manhole 2 is in proper condition for lining.
[0017] B measuring the depth x1 and diameter d1 of the manhole 2. The measurements may be taken by hand with suitable measuring tools on site. The diameter can also be known beforehand from documentation. In that case, only the depth x1 of the manhole 2 must be measured.
[0018] C taking into use a tubular liner 10 having a determined diameter d2 based on the diameter d1 measured in step B and cutting the liner 10 to a determined length x2 based on the depth x1 measured in step B. Depending on the material properties of the liner 10, the liner may either be dimensioned to exactly match the dimensions measured in step B, or the liner may be dimensioned by taking into account elasticity and stretching properties of the liner 10. The cutting of the liner 10 may be performed at installation site or beforehand at another location. In any case the shape and geometry of the manhole 2 and the liner 10 is preferable to take into consideration to ensure desired results are achieved.
[0019] D closing a first end 11 of the liner 10. As the stock liner 10 is tubular and open-ended, the first end 11 of the liner 10 that will go on the bottom of the manhole 2 must be closed in order to cover entirety of the manhole without leaving a gap at the open end. There are many alternative ways to close the first end 11 of the liner 10 but sewing or stitching the first end 11 of the liner 10, preferably directly at site is efficient both timewise and cost-wise. Alternatively, the liner may be closed beforehand, once the desired dimensions of the liner 10 are determined. Preferably, the liner 10 itself is closed, meaning that the edges of the of the liner 10 are brought together to close the liner. This allows the liner 10 to cover the entire bottom of the manhole 2 without leaving gaps that would require further manual lining steps to be performed in the manhole 2.
[0020] E impregnating the liner with 10 a hardening agent. Depending on the stock liner used, the liner 10 may be impregnated with the hardening agent on the outer surface of the liner 10 or on the inner surface of the liner 10. In case the inner surface of the liner is impregnated, the liner must be turned inside-out before the liner 10 is introduced to the manhole 2. One way to achieve turning the liner 10 inside-out is to stuff the liner to a pipe, secure the second end 12 of the liner 10 to the mouth of the pipe, and blow air from the opposite end of the pipe in order to push the first end 11 of the liner 10 out of the pipe, thus turning the liner 10 inside-out. Alternatively, also other known ways of impregnating the liner 10 with hardening agent can be used.
[0021] F securing the impregnated liner 10 to a plug cover 20 such that the plug cover 20 closes a second end 12 of the liner 10. This closes the structure airtight and allows the liner to be pressurized at will. The liner 10 may be secured to the plug cover 20 with a strap, for instance. Also, other known securing ways may be used such as clamping.
[0022] G Introducing the impregnated liner 10 to the manhole 2 with a hoisting apparatus 30, such that the first end 11 of the liner 10 reaches contact with bottom of the manhole 2. The relative height position of the liner 10 to the manhole 2 may be easily adjusted with the hoisting apparatus 30. The height of the liner 10 may be determined on the outside by observing the distance of the second end 12 of the liner 10 from the ground level when both the depth x1 of the manhole and the determined length x2 of the liner 10 are known, for instance. Alternatively, the liner 10 reaching contact with bottom of the manhole 2 may be observed through a viewing window 22 formed on the plug cover 20. This simplifies the process of confirming contact. In another embodiment, the liner 10 reaching contact with bottom of the manhole is observed via a camera device that has been mounted on the plug cover 20 and facing downwards towards the bottom of the manhole 2. This camera device set-up provides even more accurate view of the liner 10 reaching contact with the bottom of the manhole 2 and allows the worker to confirm the sight on screen instead of manually viewing it as described above.
[0023] H introducing pressure medium into the liner 10 via the plug cover 20 to force the liner 10 to expand against the inner surfaces of the manhole 2. This allows the liner 10 to cover entirety of the manhole 2 as the pressure results in the liner 10 setting against the inner surfaces of the manhole. The pressure medium may be introduced to the liner via an opening on the plug cover 20. The pressure medium may be pressurized air, for instance. In case the pressurized medium is pressurized air, a compressor 40 can be used as illustrated in figures 3 and 4. Also, other suitable pressure mediums may be used.
[0024] I accelerating hardening of the hardening agent with acceleration medium. Once it is determined that the liner has been adequately set in place and pressurized in step H, the hardening of the hardening agent can be accelerated with acceleration medium to speed up the process. The hardening agent begins to harden as soon as the liner 10 has been impregnated with it in step E, but the hardening in natural conditions is very slow. This allows the liner 10 to be properly set up in the manhole 10 but at the same time would take too long to set if no acceleration medium would be used. The acceleration medium may be introduced to the liner 10 via an opening 21 on the plug cover 20. The acceleration medium may be steam, for instance. Alternatively, the acceleration medium may be UV-light.
[0025] By implementing the method comprising the before described steps A to I, the manhole 2 is uniformly lined all the way from the bottom part of the manhole 2 to the conical upper part of the manhole. This creates a substantially seamless end result with no material transitions in the manhole, thus creating a rehabilitated manhole 2 with increased sealing properties. The method also decreases manual steps required in rehabilitation of the manhole 2, thus facilitating better work conditions, time efficiency, and cost efficiency.
[0026] After performing the steps A to I, the manhole rehabilitation can be finished by opening the water connections, and the use of the manhole can be resumed. As the process can be performed in optimal conditions in under 3 hours and during any time of the year, the disturbance to surrounding water networks is minimal.
[0027] In an embodiment, the liner 1 is elastic such that the liner 1 may expand and stretch. This allows more flexibility in terms of dimensioning of the liner 10 and removes the need for manufacturing the liner 10 to exact measurements of the manhole 2. For instance, an elastic liner 10 having diameter d2 of 600 mm may be used on manholes 2 having diameters d1 ranging from 600 mm to 1000 mm. When the difference between the diameter d1 of the manhole 2 and the diameter d2 of the liner 10 is great, shortening of the liner 10 should be accounted for when determining the length x2 of the liner 10. In other words, when using an elastic liner, preferably in step C the determined diameter d2 of the liner 10 is smaller than the measured diameter d1 of the manhole 2, and the determined length x2 of the liner 10 is greater than the measured depth x1 of the manhole 2.
[0028] In an embodiment, the method further comprises putting a smooth protective bag over the liner before introducing the liner to the manhole, the protective bag setting between the manhole 2 and the liner 10 forming a smooth surface for the liner to set against when pressurized against the inner surfaces the manhole 2 in step H. This facilitates proper setting of the liner 10 in the manhole 2 incase the inner surfaces of the manhole 2 are in rough condition. Rough condition of the surfaces of the manhole 2 could interfere with introducing the liner 10 to the manhole, as the liner could get stuck on sharp geometries.
[0029] Preferably, the liner 10 comprises glass fiber. However, also other suitable known liners 10 may be used.
[0030] Preferably, the hardening agent comprises epoxy resin. However, also other suitable known hardening agents may be used.
[0031] Figures 1 to 4 illustrate an embodiment of a lining arrangement which may be used for uniform lining of a manhole. The figures 1 to 4 illustrate the embodiment at different stages during the lining process. Figure 1 illustrates the lining arrangement 1 before step G of the method as described before. Figure 2 illustrates the lining arrangement 1 in step G. Figure 3 illustrates the lining arrangement before step H, and figure 4 illustrates the lining arrangement in step H.
[0032] The manhole lining arrangement illustrated in figures 1 to 4 comprises a tubular liner 10 comprising a closed first end 11, and an open second end 12; a plug cover 20 secured to the tubular liner 10 such that it closes the open second end 12; and a hoisting apparatus 30 for hoisting the plug cover 20 and the liner 10. The plug cover 20 comprising an opening 21 for providing pressure medium and/or acceleration medium to the liner 10 via the open second end 12. The plug cover may also comprise plurality of openings so that the pressure medium and acceleration medium can be supplied simultaneously with different devices. This arrangement facilitates efficient rehabilitation of a deteriorated manhole 2 and provides many advantages over the known solutions. One major advantage provided by the arrangement 1 is that it allows the entire manhole to be lined with one operation, and manual laminating of the bottom of the manhole 2 and the upper part of the manhole 2 can be avoided. This results in faster results and is more enjoyable for the workers, as work in tight spaces underground is minimized. This arrangement also results in being able to line the entire manhole 2 with minimal seams and material transitions in the lining.
[0033] Preferably, the lining arrangement may comprise any features that have been described before in connection with the method for uniformly lining a manhole.
1. A method for uniform lining of a manhole (2), the method comprising:
(A) preparing the manhole (2) for lining by clearing the manhole (2);
(B) measuring the depth (x1) and diameter (d1) of the manhole (2);
(C) taking into use a tubular liner (10) having a determined diameter (d2) based on the diameter (d1) measured in step (B) and cutting the liner (10) to a determined length (x2) based on the depth (x1) measured in step (B);
(D) closing a first end (11) of the liner (10) such that the liner (10) covers entirety of the manhole in step (H);
(E) impregnating the liner with (10) a hardening agent;
(F) securing the impregnated liner (10) to a plug cover (20) such that the plug cover (20) closes a second end (12) of the liner (10);
(G) introducing the impregnated liner (10) to the manhole (2) with a hoisting apparatus (30), such that the first end (11) of the liner (10) reaches contact with bottom of the manhole (2);
(H) introducing pressure medium into the liner (10) via the plug cover (20) to force the liner (10) to expand against the inner surfaces of the manhole (2); and
(I) accelerating hardening of the hardening agent with acceleration medium.
2. The method according to claim 1, wherein the liner (10) is elastic such that the liner
(10) may expand and stretch.
3. The method according to claim 2, wherein in step (C) the determined diameter (d2)
of the liner (10) is smaller than the measured diameter (d1) of the manhole (2), and
the determined length (x2) of the liner (10) is greater than the measured depth (x1)
of the manhole (2).
4. The method according to any of the previous claims, wherein the liner (10) is dimensioned
such that the liner (10) lines entirety the manhole (2).
5. The method according to any of the previous claims, wherein in step (H) the liner
(10) reaching contact with the bottom of the manhole (2) is observed via a viewing
window on the plug cover (20) or a camera device mounted on the plug cover (20).
6. The method according to any of the previous claims, wherein in step (D) the closing
of the first end (11) of the liner (1) is performed by sewing or stitching the first
end (11).
7. The method according to any of the previous claims, wherein the inner surface of the
liner (10) is impregnated with the hardening agent in step (E), and the method further
comprises flipping the impregnated liner (10) inside out before introducing it to
the manhole (2).
8. The method according to any of the previous claims, wherein the method comprises putting
a smooth protective bag over the liner before introducing the liner to the manhole,
the protective bag setting between the manhole (2) and the liner (10) forming a smooth
surface for the liner to set against when pressurized against the inner surfaces the
manhole (2) in step (H).