Patent Description:
In particular, the duct could be used in a civic water-supply system and be traversed by water or it could be intended to convey a fluid for industrial use.

The known ducts comprise multiple pipes connected together via welded joints, interception elements, or connection joints.

More specifically, the duct has multiple points anchoring it to the ground and the pipes may be fitted inside the interception elements and connection joints.

The flow of fluid inside the duct and the pressure inside the duct itself determine an axial force on the components/joints downstream and upstream of the pipe and on the pipe itself with reference to a forward direction of the fluid. This axial thrust is generated, for example, where there are curved sections of the duct or when the interception elements are being closed.

As a result, the pipe tends to slide out of the interception elements or the connection joints.

According to some known solutions, the pipe is axially fixed to the interception elements or to the connection joints using adhesive substances.

In the sector, there is a need to limit, as much as possible, the risk of slipping out by using adhesives as little as possible.

This need is particular felt in the case of repairs to already existing ducts having a broken area, according to a technology known as Cured-In-Place-Pipe (CIPP).

According to this technology, a tubular element (also known as a liner) made of polyester felt or glass fibre is preliminarily imbued with a thermosetting resin (called a carrier) - polyester, vinyl ester, or epoxy resin - suitable for resisting the chemical action of fluids conveyed in the duct, and, following this, inserted inside the pipe to be repaired, which assumes the function of host pipe.

The sheath is then inflated inside the host pipe, so as to bear it perfectly in contact with the walls of the pipe itself.

Once inserted and inflated, the tubular element imbued with resin is made to harden through the curing/polymerization of the resin with which it is imbued, until it adheres to the host pipe to be repaired.

In particular, polymerization of the resin may occur thanks to the administration of heat using hot water or superheated steam or radiant energy via ultraviolet ray emitters.

When the consolidation is finished, the hardened sheath is cut at intermediate and end inspection wells.

The end contact points between the sheath and host pipe are sealed via the manual application of special chemically binding putties or by using specific seals.

<CIT> discloses a duct according to the preamble of claim <NUM> and a method for producing a duct according to the preamble of claim <NUM>. The purpose of this invention is to produce a duct, which meets, easily and economically, at least one of the needs described above.

The above-mentioned purpose is achieved with a duct according to what is claimed in claim <NUM>.

This invention also relates to a method for producing a duct according to what is claimed in claim <NUM>.

To better understand this invention, a preferred embodiment is described below, by way of non-limiting example and with reference to the attached drawings, in which:.

With reference to the figures attached, the reference number <NUM> indicates a duct for conveying a pressurised fluid.

The pressurised fluid may be for civic or industrial use.

The duct <NUM> comprises multiple conveyor pipes <NUM> for conveying fluid connected together in a fluid-tight manner, only one of which is illustrated in <FIG>.

Each pipe <NUM> extends along its own axis A.

With reference to <FIG>, the duct <NUM> comprises, in addition, for each pipe <NUM>:.

Hereinafter in this description, only one pipe <NUM> is described and the corresponding flanged elements <NUM>, connection elements <NUM>, and seals <NUM>, since the pipes <NUM> are identical to each other.

In particular, the duct <NUM> is fixed in a known way to the ground at multiple anchorage points not illustrated in the attached figures.

The flanged elements <NUM> also comprise:.

In the example illustrated in <FIG>, the surfaces <NUM> are flat.

The surfaces <NUM> define respective ends <NUM> of the pipe <NUM>.

The surfaces <NUM> and <NUM> comprise respective corrugations <NUM>, <NUM> coupled together so as to axially hold the pipe <NUM> inside the flanged elements <NUM>; the corrugations <NUM>, <NUM> have greater extensions parallel to the axis A and a thickness radial to the axis A and smaller than the extension along the axis A itself.

The term "corrugation" refers, hereinafter in this description, to a succession that is continuous, or continuous in sections, and periodic of annular ridges and groves around the axis A.

The corrugation has, in one section containing the axis A:.

The corrugations <NUM>, <NUM> are preferably coupled without the use of adhesive.

The coupling between the corrugations <NUM>, <NUM> generates an axial reaction on the pipe <NUM> that counters the dynamic action axially exerted by the fluid in the pipe <NUM>. This action is exerted, for example, by the dynamic conditions or by the static pressure of the fluid.

By way of non-limiting example, this action is generated at curved sections of the pipe <NUM> or during closure of the valves arranged downstream of the pipe <NUM> itself with reference to the forward direction of the fluid.

Hereinafter in this description, only one corrugation <NUM> is described, since the other corrugation <NUM> is identical to the first corrugation <NUM>.

More specifically, the corrugation <NUM> comprises multiple repeated modules <NUM>, identical to each other and arranged consecutively parallel to the axis A.

Each module <NUM> extends coaxially to the axis A and comprises, in particular, proceeding parallel to the axis A in a direction oriented by one of the flanged elements <NUM> towards the other flanged element <NUM> (<FIG>, <FIG>, and <FIG>):.

The section <NUM> is connected to the section <NUM> of the corresponding module <NUM> and to the section <NUM> of a module <NUM> adjacent to it via a pair of pipe fittings with the radius r.

The section <NUM> is connected to the sections <NUM>, <NUM> via a pair of pipe fittings with the radius r.

In particular, the axial extension of the sections <NUM>, <NUM> is equal.

The sections <NUM>, <NUM> respectively define ridges and grooves of the respective corrugations <NUM>, <NUM>.

The extension parallel to the axis A of the sections <NUM>, <NUM> is equal and greater than the axial extension of the sections <NUM>, <NUM>.

The sections <NUM>, <NUM> have respective disposition planes P, Q tilted between them at the same acute angle α in relation to the axis A.

The sections <NUM>, <NUM> are symmetrical in relation to a radial median plane of the section <NUM> of the same module <NUM>.

The duct <NUM> comprises, in addition, multiple annular seals <NUM> of axis A placed axially between respective ends <NUM> of the pipe <NUM> and corrugations <NUM> of corresponding flanged elements <NUM> so as to prevent fluid from accessing the area between the above-mentioned ends <NUM> and the respective corrugations <NUM>.

To this end, the corrugations <NUM> are axially shorter than the corresponding corrugations <NUM> and end at an axial distance from the above-mentioned corrugations <NUM> so as to enable the fixing of the corresponding seals <NUM>.

Each connection element <NUM> is, in the example illustrated, shaped like a tubular body bolted, at corresponding head surfaces <NUM> of opposite axial ends, to the flanged elements <NUM> of corresponding pipes <NUM>.

Each seal <NUM> is axially placed in contact between one corresponding flanged element <NUM> and a related connection element <NUM>.

Each flanged element <NUM> comprises, in the example illustrated, a pair of half-bearings <NUM> bolted to each other (<FIG>).

With reference to the embodiment illustrated in <FIG>, the pipe <NUM> is housed in a fluid-tight manner inside a host pipe <NUM> having a broken area <NUM>.

In this way, the pipe <NUM> implements a technology known as cured-in-place-pipe.

In particular, the pipe <NUM> is shaped starting from a tubular closed sheath <NUM> preliminarily imbued with a thermosetting resin (called a carrier) - polyester, vinyl ester, or epoxy resin - suitable for resisting the chemical action of the fluids conveyed in the duct, and, following this, inserted inside the host pipe <NUM> (<FIG>).

The sheath <NUM> is then inflated inside the host pipe <NUM> so as to make it adhere perfectly to the walls of the host pipe <NUM> itself (<FIG>).

Once inserted and inflated, the sheath <NUM> imbued with resin is made to harden through the curing (polymerization) of the resin with which it is imbued, until it forms the pipe <NUM> adhering to the pipe <NUM> to be repaired at the area <NUM> (<FIG>).

When the consolidation is finished, the hardened sheath <NUM> is cut at the ends <NUM>, or intermediate inspection wells that are not illustrated.

When the pipe <NUM> is intended to be inserted in the host pipe <NUM>, the section <NUM> of each module <NUM> and the flanged elements <NUM> comprise respective multiple radial holes <NUM>, which are through holes and angularly spaced equally around the axis A. The holes <NUM> are designed to enable the escape of the gas that is produced during the hot polymerization of the sheath <NUM>, and normally trapped between the fibres of the sheath <NUM>, or to enable the evacuation of air that, during the step in which the sheath <NUM> approaches the surface <NUM>, would remain trapped, preventing the correct coupling of the surfaces <NUM>, <NUM>.

In the example illustrated, the pipe <NUM> is a made of glass fibre or polyester felt.

The flanged element <NUM> is, in addition, with reference to the example illustrated, produced as a single body made via melting or mechanical sintering techniques (<FIG>).

The assembly and operation of the duct <NUM> is described below in relation to just one pipe <NUM>.

During the assembly of a new duct <NUM> or repair of the duct <NUM> itself, the ends <NUM> of the pipe <NUM> are housed in the open half-bearings <NUM> of the corresponding flanged elements <NUM>. Following this, the half-bearings <NUM> are closed so as to precisely couple the corrugations <NUM>, <NUM> and solidly fix the pipe <NUM> to the corresponding flanged elements <NUM>. The flanged elements <NUM> with the closed half-bearings <NUM> bolted together are, at this point, fixed to the ground.

When repairing the host pipe <NUM>, according to the technology known as cured-in-place-pipe, the sheath <NUM> is housed inside the host pipe <NUM> at the broken area <NUM> and the flanged elements <NUM> are connected to corresponding, opposite axial ends of the host pipe <NUM> (<FIG>).

The sheath <NUM> is then inflated inside the host pipe <NUM> so as to make it adhere perfectly to the walls of the host pipe <NUM> itself. The radial holes <NUM> enable the escape of the gas housed inside the sheath <NUM> that is needed for the inflation thereof (<FIG>).

Once inserted and inflated, the sheath <NUM> imbued with resin is made to harden through the curing (polymerization) of the resin with which it is imbued, until it forms the pipe <NUM> adhering to the pipe <NUM> to be repaired at the area <NUM>.

When the consolidation is finished, the hardened sheath <NUM> is cut at the ends <NUM>, or intermediate inspection wells that are not illustrated (<FIG>).

Both when laying a new duct <NUM> and when repairing the damaged duct <NUM>, the movement of the fluid generates an axial thrust on the pipe <NUM> that would tend to make it slip out of the connection elements <NUM>. In particular, the pressure acting on the components downstream or upstream of the pipe <NUM> with reference to the direction in which the fluid flows generates a similar axial thrust on the pipe <NUM> itself. This axial thrust is generated, by way of non-limiting example, at curved sections of the pipe <NUM> or when the interception elements arranged downstream of the pipe <NUM> itself are being closed.

This axial thrust is counteracted by the coupling between corrugations <NUM> and <NUM>, which ensure a stable and correct positioning of the pipe <NUM> in relation to the connection elements <NUM>.

At the same time, the pressure of the fluid generates a radial thrust on the corrugation <NUM> that keeps the corrugation <NUM> firmly in contact with the corrugation <NUM>, increasing the binding action exerted on the pipe by the coupling between the corrugations <NUM>, <NUM>.

The seals <NUM> ensure the fluid-tight connection between the pipe <NUM> and the pipes <NUM> adjacent to it of the duct <NUM>.

The seals <NUM> ensure the fluid-tight connection between the corrugations <NUM>, <NUM>.

From an examination of the duct <NUM> and the method according to this invention, the advantages that it enables are clear.

In particular, the coupling between the corrugations <NUM>, <NUM> generates an axial reaction thrust on the pipe <NUM> that counters the dynamic action exerted on the pipe <NUM> itself by the fluid that flows inside of the same pipe <NUM>.

This coupling also counteracts the same axial action that the pressure acting on the components downstream or upstream of the pipe <NUM>, with reference to the direction in which the fluid flows, and rigidly connected to it, may generate on the pipe <NUM> itself.

It is, thus, possible to ensure the stable and precise positioning of the pipe <NUM> in relation to the connection elements <NUM>.

Moreover, the binding action of the pipe <NUM> in relation to the connection elements <NUM> is increased by the pressure of the fluid flowing inside the pipe <NUM>. This pressure, in fact, generates the radial thrust between the corrugations <NUM>, <NUM> ensuring its stable contact radial to the axis A.

It is important to highlight how this binding action is obtained without the use of adhesives between the corrugations <NUM>, <NUM>, but simply thanks to the shape coupling between the corrugations <NUM>, <NUM>.

It is, also, important to highlight how the seal between the pipes <NUM> and the connection elements <NUM> is obtained thanks to the seals <NUM>, i.e., thanks to the elements separate from the corrugations <NUM>, <NUM>.

Finally, it is clear that the duct <NUM> and the method described above may be altered, or variations may be produced thereof, without, as a result, departing from the scope of protection of this invention as disclosed in the appended claims.

In particular, the duct <NUM> may comprise, instead of one or both flanges <NUM>, corresponding interception elements, valves, or hydraulic joints, provided with the surface <NUM> with the corrugation <NUM>.

Each pipe <NUM> could, in addition, be produced in subparts assembled using electrowelding.

Each pipe <NUM> could, in addition, be formed from two half-bearings joined using plates bolted together.

The flanged elements <NUM> could, in addition, be produced using mechanical processing, moulding, melting, sintering, electrowelding, or cold or hot plastic deformation.

The flanged elements <NUM> could, in addition, be welded to the connection elements <NUM>.

Claim 1:
A duct (<NUM>) comprising:
- a pipe (<NUM>) for conveying a fluid, extending along an axis (A) and comprising a first portion (<NUM>);
- a coupling element (<NUM>) fitted to said pipe (<NUM>) comprising a second portion (<NUM>) fitted to said first portion (<NUM>), which can be connected directly or indirectly to another conveyor pipe (<NUM>) of said duct (<NUM>) ;
said first portion (<NUM>) and second portion (<NUM>) respectively comprising a first corrugation (<NUM>) and a second corrugation (<NUM>) coupled together so as to axially hold said pipe (<NUM>) to said coupling element (<NUM>);
said first and second corrugations (<NUM>, <NUM>) having an extension axial and thickness radial to said axis (A); said radial thickness being smaller than said axial extension;
each of said first and second corrugations (<NUM>, <NUM>) comprising multiple repeated modules (<NUM>), identical to each other and consecutively arranged parallel to said axis (A);
each said module (<NUM>) comprising:
- a first section arranged (<NUM>) at a first radial distance from said axis (A); and
- a second section arranged (<NUM>) at a second radial distance from said axis (A);
said second distance (<NUM>) being shorter than said first distance (<NUM>);
characterised in that it comprises, in addition, a host pipe (<NUM>) having a damaged area (<NUM>);
said conveyor pipe (<NUM>) being fitted coaxially inside said host pipe (<NUM>) and cooperating in a fluid-tight manner with the host pipe (<NUM>);
said conveyor pipe (<NUM>) being inserted, in use, inside said host pipe (<NUM>) in the form of an inflatable sheathing (<NUM>);
said first section (<NUM>) of each module (<NUM>) comprising at least one through hole (<NUM>) arranged radially to said axis.