RU168691U1 - Insulated pipe with multilayer working pipes - Google Patents

Abstract

A multilayer insulated pipe refers to pipeline transport systems, namely, to the design of thermally insulated pipes, and can be used for channelless installation of heating systems, hot and cold water supply. An insulated pipe contains an external waterproof sheath (4), the wall of which is made with screw-shaped corrugations and two or more working pipes (1), the wall of which is made of multilayer cross-linked polymer reinforced material with screw-shaped corrugations located only on the outer surface of the working pipe or along outer and inner surfaces. The helical shape of the wall of the waterproof shell and the walls of each working pipe, as well as the material used to make the working pipe, increases the flexibility of a multilayer insulated pipe without compromising its strength and performance. 3 ill.

Description

The utility model relates to pipeline transport systems, namely, to the construction of hydro-thermally insulated pipes and can be used for channel-free installation of heating systems, hot and cold water supply, etc.

From the prior art, various designs of hydro-thermally insulated pipes and lines realizing them are known: DE 3126505; DE 3724360; DE 10312700; DE 19629678; DE 3717020; DE 3724360; EP 0038974; DE 19629678; EP 01566587; EP 1612468; EP 2060843; EP 2,138,751; EP 1010933; FR 2578026; JP 58020424; JP 2002323194; JP 58020425; JP 58076235; SU 1449025; RU 2265517; RU 2289751; RU 2293247; RU 2320484; RU 2339869; RU 2355941; RU 2372551; RU 11585U1; RU 2052706; RU 2280809; RU 96123112; RU 2003117471; RU 2004139112; US 4,844,762; US 4,929,409; WO 0035657; WO 0207948; WO 0231400; WO 0047387.

The main disadvantage of the above hydro-insulated pipes is the design complexity, requiring specialized equipment and involving the manufacture of insulated pipes in several successive technological steps.

A technical solution is known RU 2437025 dated 12/17/2009, according to which in a thermally insulated pipe with at least one internal culvert (working pipe), a layer of thermal insulation surrounding it, as well as a corrugated outer shell of thermoplastic polymer, the walls of the culverts are made of heat-resistant elastomer with a glass transition temperature of -45 ° C and heat resistance of 110-150 ° C, the outer shell has a thickness of not more than 5 mm and is corrugated with a depth of D / 10-D / 4 and with a step of corrugation D / 30-D / 10, providing an annular rigidity and flexibility l pipes, where D is the outer diameter of the outer pipe, taken along the corrugation tops.

Smooth surfaces, internal and external, culverts (working pipes) determine the increased stiffness of the entire product, and the presence of one element in the design, in the form of an outer shell with corrugation, is not enough to ensure the flexibility of the device.

Rigidity is understood as the ability of a body or structure to resist the formation of deformation (tensile, bending, torsion, etc.). Rigidity depends on the geometric characteristics of the cross section and the physical properties of the material (elastic moduli).

A technical solution is known for a multilayer pipe (KZ U 962, class F16L 11/10, publ. 06/14/2013), containing the inner polymer pipe, its reinforcement by reinforcement with high-strength threads, an outer shell of olefin polymer, equipped with protective layers and a thermal insulation layer . The inner tube is made of a cross-linked olefin polymer, characterized by tear resistance at 115 ° C of at least 15 N / mm, the reinforcement is located between the tread layers made of a polymer selected from the group consisting of polypropylene, ethylene-propylene copolymer, polybutene, ethylene-octene copolymer alloys of olefin polymers with different polymers, the first tread layer being located between the outer surface of the inner pipe and the reinforcing threads, and the second tread layer is located between reinforcing strands and the inner surface of the heat-insulating layer.

A technical solution is known for a multilayer insulated pipe used for hot water supply and heating systems, known as "Isoproflex 135" http://www.polymerteplo.ru/products/ISOPROFLEX-135A/?SESS816ffece7b2e3b0e0dfdcb3f548ae9e9=4j21vhhbna which is a multi-layer structure of high-temperature polymers of special grades reinforced with high-modulus fibers, containing several tread layers, enclosed in a protective sheath of polyethylene and placed between them, a layer of t heat insulation.

The above technical solutions KZ U 962, publ. 06/14/2013, and "Isoproflex 135" are similar in technical essence and are aimed at ensuring the strength characteristics of the working pipe, but also have increased rigidity. This is due to the fact that in these technical solutions a work pipe having a circular cross section is made with smooth surfaces (inner and outer), which, firstly, significantly reduces its flexibility, despite the fact that to reduce the wall thickness of the working pipe provided for its strengthening due to reinforcement. Secondly, the inner layer of thermal insulation adjacent to the surface of the working pipe is also smooth, which leads to an increase in the negative effect - to increase stiffness, while the presence in the pipe structure of only one element in the form of an outer shell having corrugation is not enough to provide flexibility .

Due to the above factors, the increased rigidity of the entire design of the device complicates the installation process of the pipeline, increases the complexity and increases the time for this operation. To eliminate the above drawbacks, in some cases, the multilayer working tube is heated from the inside, which entails additional temporary losses and increases energy consumption.

Another drawback of these constructions is that in practice, in order to ensure the efficiency of storage and transportation, the heat-insulated pipe, in the manufacturing process, is wound into a ring and fixed in this form, for example, using couplers, and during installation, the couplers are removed and deploy the pipe. Bending stresses acquired during the winding process are dangerous for the health of personnel who carry out their installation (deployment) in the field and can lead to accidents. It is worth noting that the described method of production, storage or transportation is used for all types of flexible pipes, including pipes with a metal working pipe.

A number of devices are known having in their construction a metal working pipe for a coolant, a thermal insulation layer covering the working pipe and a corrugated polymer shell. An example of such a design can serve as RU 2450926 from 06/28/2010; RU 2494870 dated 09/20/2010, as well as similar BY 9475 dated 11/20/2012; KZ U 989 06/27/2012 or pipeline system, marketed under the name Casaflex (www.pipesystems.com).

These devices containing a corrugated metal working pipe in their construction have a number of disadvantages and limitations associated with the high electrical conductivity of the material of the working pipe and, therefore, need protection from stray currents. The material of the working pipe (metal), which has a high coefficient of thermal conductivity, is heated during operation due to the heat transfer obtained from the coolant, and thereby destroys the adjacent insulation layer, which is why the thermal conductivity of the pipeline system increases and its heat loss increases.

Additional disadvantages of the above constructions are also: overgrowth of the inner cavity of the pipe with hardness salts and low resistance to aggressive environments. In addition, the manufacture of a metal pipe, as a rule, implies the presence of a weld that is susceptible to corrosion and thereby reduce the operational properties of the device as a whole.

The problem solved by the utility model is the elimination of the above disadvantages while increasing the flexibility of the insulated pipe.

The technical result, which the utility model aims to achieve, is to obtain a design of an insulated multilayer pipe of increased flexibility, which ensures a reduction in bending stresses both during production and during storage, transportation and deployment at the installation site of the pipeline. The increased flexibility of the insulated pipe, due to the proposed design and material of the working pipe, does not impair the basic operational, strength characteristics and parameters, for example, such as resistance to aggressive influences of the external and internal environment. Due to the increased flexibility of the insulated pipe, installation work in the field is accelerated, as labor costs are reduced and the convenience of work during installation of the pipeline is increased.

The claimed design of an insulated pipe includes the following features that are common with the closest analogue of RU 2450926: an external waterproof cover, the wall of which is made with screw-shaped corrugations, at least one working pipe with a corrugated external wall and an insulation layer located between them.

Distinctive features of the claimed design is that the insulated pipe contains two working pipes or more than two working pipes, while the corrugated wall of each working pipe is made, like the wall of the external waterproof pipe-shell, with screw-shaped corrugations located only on the outer surface or along outer and inner surfaces, and the insulation layer enclosed between them, the surfaces of which are facing the outer surface of the working pipes and the inner surface of the waterproof shell, repeating There is a helical contour of the surfaces of the working pipes and the inner surface of the waterproof shell; in addition, each working pipe is made of a multilayer plastic, i.e. the wall of the working tube contains several layers of plastic and, in addition, is reinforced by reinforcement.

The claimed device contains in its composition several elements, the design of which allows to reduce rigidity and increase flexibility. The technical result is achieved due to distinctive features, which include: firstly, the helical shape of the outer surface of the wall of each working pipe, which increases its flexibility compared to the closest analogue, and secondly, the multilayer working pipe and the choice of plastic material as the working pipe , which also positively affects flexibility; thirdly, the formation in the manufacture of pipes of the insulation layer with helical surfaces - the inner, adjacent to the surface of the working pipe, and the outer, adjacent to the surface of the waterproof pipe-sheath, repeating the shape, thereby increasing the flexibility of the insulation layer and the insulated pipe as a whole.

The above distinguishing features are associated with a causal relationship with the technical result - increasing the flexibility of the insulated pipe without loss of insulating properties and strength characteristics. The specified technical result is achieved by introducing a helical surface shape of each working pipe in addition to the helical shape of the wall of the outer waterproof sheath, and the helical profile has a smooth transition of alternating peaks and troughs. Replacing the circular cross section of the working pipe and the cross section of the surface of the insulation layer adjacent to it with a variable cross section increases the flexibility of the product, makes the walls of the insulated pipe easier to bend, i.e. simultaneously stretch / contract. The presence of alternating peaks and troughs of a helical surface, with a smooth transition between them, ensures uniformity and stability of the perception of loads, and the insulation layer made of closed-cell elastic or semi-rigid polyurethane foam (PUF) will additionally increase the indicated technical effect.

The achievement of the technical result is due to the following reasons that give design flexibility to a multilayer insulated pipe (reduce its rigidity), which is especially important in the presence of two (or more) working pipes.

The execution of the working pipe with a helical outer surface of the wall due to the presence of uniformly alternating protrusions and depressions, firstly, will change the geometric characteristics of its cross section, thereby reducing rigidity and at the same time increase the flexibility of the working pipe. Secondly, a decrease in the rigidity of the working pipe will reduce the bending stresses that arise during the winding of a multilayer insulated pipe for its transportation, and, accordingly, will secure the work of personnel in the field during pipe unwinding. Thirdly, the claimed form of the working pipe will not cause difficulties when making permanent connections of working multilayer pipes with each other by known methods, for example, by welding, and the execution of a helical surface (with alternating successively arranged protrusions and depressions) on the working pipe will not affect the reduction of its strength and operational characteristics due to the fact that with this shape of the wall of the working pipe, it is made of multilayer, and reinforced with reinforcement.

The technical result is achieved by simultaneously increasing the flexibility of the insulation layer, by obtaining identical helical surfaces on its corresponding surfaces adjacent to the working pipe and the outer waterproof sheath, covering and repeating the outer contour of the working multilayer pipe and adjacent to the inner surface of the outer waterproof sheath.

The working pipe has a wall thickness of not less than 1 mm, and the materials used for manufacturing the working pipe are mainly cross-linked (PEX) plastics or polymer alloys, with an oxidation degradation onset temperature of at least 240 ° C, having a degree of crosslinking of at least 65% and a minimum long-term strength (MRS) from 0.6 MPa, for example, crosslinked polyolefins.

Due to the fact that the shape of the wall of the working pipes has changed to screw-like, to ensure its flexibility, while maintaining the required operational and strength characteristics, the reinforcement provided for them will increase the strength, reduce the wall thickness, and accordingly, and will not reduce its flexibility. Reinforcing a working pipe made of plastic with a helical profile of the wall surface allows the operation of an insulated pipe with an internal pipeline pressure of up to 5 MPa. Reinforcement is carried out through the use of high-strength fibers, threads or tapes, or a combination thereof, for example, thread-fiber, fiber-tape, thread-tape, etc. made of polymeric materials, for example, polyester, aramid. Reinforcement is carried out by known methods, for example, by tightly covering the surface of the working pipe, and the thickness of the reinforced layer can reach up to 5 mm.

Depending on the operating conditions, it is permissible to reinforce a multilayer working pipe with a helical profile of the surface, at least in one layer, with a reinforced layer thickness of up to 3 mm, which is quite sufficient for operating the pipeline up to 2.5 MPa inclusive.

In addition, in order to improve the quality of the working pipe, known intermediate layers up to 1 mm thick can be additionally applied to it, which do not affect the change in flexibility, for example, to combine layers and surfaces (adhesive), which prevent diffusion of gases (barrier), etc.

It is advisable that the insulation layer had a closed-cell structure and was made of foamed compositions, for example, from flexible or semi-rigid polyurethane foam (PUF) for flexible pipelines (for example, products from BASF, Dow Chemical, etc.) or from polyisocyanurate (GTR). The thermal insulation layer made of these materials is capable of working for a long time without the manifestation of destruction. When using elastic or semi-rigid PPU or PIR for the manufacture of a thermal insulation layer, a single, non-separable, structure is formed in the form of an insulated multilayer pipe, in which the insulation layer repeats the corresponding contours of the adjacent surfaces of the working pipes and the waterproof shell.

To increase flexibility, while providing the necessary physical, mechanical and operational properties, the outer waterproof shell made of polymeric materials can also be multilayer. For example, the wall of the outer waterproof cover may contain at least one barrier layer that protects against diffusion of gases or penetration of other substances, as well as at least one adhesive layer for combining adjacent layers or waterproof cover with an insulation layer.

The location of the barrier and adhesive layers is selected in such a way as to prevent damage, for example, they are placed in the middle layer of the waterproof shell, namely, along the diameter of the middle line of the waterproof shell, or on the inner surface of the waterproof shell, while the thickness of the above layers should not exceed 1 mm

In accordance with paragraph 3.6 of GOST P 53630-2009 “Pressure multilayer pressure pipes for water supply and heating systems”, the barrier layer is a layer with low oxygen permeability. It is predominantly made from copolymers of ethylene and vinyl alcohol EVOH (Eng. Ethylene-vinyl alcohol) and is carried out in a single pass simultaneously with the extrusion process of the outer waterproof sheath or multilayer working pipe.

Each multilayer working pipe can be made with a screw-shaped wall or a combined shape with an outer surface of a helical shape and an internal smooth-walled surface.

The design of the pipe made in this way has a variable cross section, which increases its flexibility and reduces the rigidity of the device as a whole, reduces the bending stresses that occur during winding and deployment, allows the use of less energy-intensive equipment during winding due to the flexibility of the insulated pipe, and ensures safety in the field for technical personnel, reducing the risk of workplace injuries during deployment. Moreover, the claimed design allows you to use it as a full-fledged section of the pipeline, with high heat-insulating properties, two connection points for the coolant (input and output), compensating for linear deformations when the temperature of the coolant changes.

An important advantage of the proposed design of an insulated multilayer pipe is that it can be used as a high-pressure pipeline for transporting liquids or gases, while the working capacity and its service life, for example, under high pressure, is reduced to the number of reinforced pipes applied to the working pipe layers and in practice, mainly used in the range from 0.6 MPa to 2.5 MPa.

The essence of the claimed utility model with various embodiments is illustrated by drawings.

FIG. 1 - insulated multilayer pipe with two working pipes made with a wall of a helical profile on the outer and inner surfaces, general view.

FIG. 2 - insulated multilayer pipe with two working pipes made with a wall having a screw-shaped outer and screw-shaped inner surface of the working pipe, a cut along the working pipe.

FIG. 3 is an embodiment of a multilayer insulated pipe with a helical outer and smooth inner surface, shown along the working pipe.

FIG. 4 - insulated multilayer pipe with three working pipes made with a wall of a helical profile on the outer and inner surfaces, general view.

FIG. 5 - insulated multilayer pipe with four working pipes made with a wall of a helical profile on the outer and inner surfaces, general view.

A multilayer insulated pipe contains two or more working pipes 1 and a waterproof pipe-sheath 4, while the wall of each of the working pipes 1 has a helical surface. The working pipes 1 are enclosed in an insulation layer 2 of foaming compositions (PUF, PIR) filling the annular space between the hydroshield pipe-sheath 4 and the working pipes 1, see FIG. one.

In the insulation layer 2, conductors 3 of an operational remote control system (SODC) can be additionally installed inside the outer waterproof pipe - sheath 4. The wall of the waterproof pipe-sheath 4 has a screw shape and is made of a polymer material. Moreover, each working tube 1 can have both a corrugated screw-shaped inner surface 5 and a smooth-walled inner surface 6. The working tube 1 is multilayer and includes reinforcement by reinforcing 7, as well as intermediate layers 8, for example, adhesive - adhesive, or adhesive - barrier , but at least one adhesive and at least one barrier.

Reinforcement 7 of the working pipe 1 is performed by high-strength threads, fibers, tape, or a combination thereof.

The production of an insulated multilayer pipe is carried out in a continuous way, preferably in one step in the overall composition of the line.

The working pipes 1 are made by extrusion, with the formation of a knurled surface profile on their walls. As part of the line, the material of the working pipe is stitched, at least one adhesive, at least one barrier layer is applied and reinforced with reinforcement 7. Reinforcement is always carried out between the applied layers, and, depending on the conditions and nature of operation, subsequent application of additional layers is possible on the working pipe .

The working pipes are obtained in one or as part of separate extrusion lines, or, previously manufactured multilayer working pipes wound on coils, are fed through a guiding device installed behind the passage through the extrusion head, thus forming a bundle of two or more working pipes. One end of each multilayer working pipe is fixedly fixed in the inner cavity of the hydroprotective shell, to the end of which, after the fixing of the working pipes, the prepared polymer melt is attached and the external hydroprotective shell is extruded, simultaneously forming screw-shaped corrugations on its surface. Through the guiding device and the bushing extrusion head, simultaneously supply the working pipes, and from the filling machine, the components that form the thermal insulation layer. The extrusion rate of the hydroprotective shell is set slightly higher than the feed rate of the working pipes, which allows tensioning of the pipes, and the supply of working pipes through the guide device allows you to place the formed bundle of working pipes in the required position in the inner cavity of the waterproofing shell. At the same time, components are introduced into the inner cavity of the hydroprotective shell, which foam expand to fill the inner space between the working tubes and the hydroprotective shell, and after cooling and completion of the polymerization process, form a thermal insulation layer. After that, the finished insulated pipe with multilayer working pipes is wound on coils, and, to prevent unwinding, the insulated pipe is fixed with ties. Spooling is improved due to the increased flexibility of the proposed multilayer pipe design.

After transportation, at the installation site, a multilayer insulated pipe is placed in a pre-prepared trench and deployed. The last two operations are also greatly simplified due to the increased flexibility of the proposed design of a multilayer insulated pipe.

Claims (14)

1. A multilayer insulated pipe containing an external waterproof sheath, the wall of which is made with screw-shaped corrugations, as well as a working pipe with a corrugated wall and an insulation layer located between the waterproof sheath and the working pipe, characterized in that the number of working pipes in the multilayer insulated pipe is more than one, and the wall of each working pipe is made of multilayer cross-linked polymer reinforced material with screw-shaped corrugations located on the outer surface, at the insulation layer is made of foam 2. A multilayer insulated pipe, characterized in that the inner wall of the working pipe is helical, repeating the shape of the outer surface. 3. A multilayer insulated pipe, characterized in that the inner wall of the working pipe is made smooth. 4. The multilayer insulated pipe according to claim 1, characterized in that the multilayer working pipe is made of heat-resistant plastic with an operating temperature of up to 200 ° C and an operating pressure of up to 2.5 MPa. 5. A multilayer insulated pipe according to claim 1, characterized in that the working pipe is made of a heat-resistant polymer alloy with an operating temperature of up to 200 ° C and an operating pressure of up to 2.5 MPa. 6. A multilayer insulated pipe according to claim 1, characterized in that the reinforcement of the working pipe is made of high-strength threads. 7. A multilayer insulated pipe according to claim 1, characterized in that the reinforcement of the working pipe is made of high-strength fibers. 8. A multilayer insulated pipe according to claim 1, characterized in that the reinforcement of the working pipe is made of high strength tape. 9. A multilayer insulated pipe according to claim 1, characterized in that the wall of the working pipe is made with at least one adhesive layer. 10. A multilayer insulated pipe according to claim 1, characterized in that the wall of the working pipe is made with at least one barrier layer that prevents the diffusion of gases. 11. A multilayer insulated pipe according to claim 1, characterized in that the insulation layer is made of elastic foamed polyurethane foam. 12. A multilayer insulated pipe according to claim 1, characterized in that the insulation layer is made of semi-rigid foamed polyurethane foam. 13. A multilayer insulated pipe according to claim 1, characterized in that the insulation layer is made of flexible foam polyisocyanurate foam. 14. A multilayer insulated pipe according to claim 1, characterized in that the insulation layer is made of semi-rigid foamed polyisocyanurate foam.

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