RU2204757C2 - Multi-layer tube - Google Patents

Abstract

FIELD: manufacture of tubes, metallopolymer tubes with heat-insulating coat is particular. SUBSTANCE: tube has porous element embracing it on the outside. Proposed metallopolymer tube is made form aluminum or copper or alloys on their base; thickness of tube wall ranges from 0.1 mm to 7.0 mm; tube is provided with polymer coat applied to inner and outer surfaces, 0.1 to 3 mm thick. Porous element is made from foamed polyolefin at density of 100 to 500 kg/cu m. Ratio of outer diameter D_p.el of porous element to outer diameter D_m.p.t. of metallopolymer is no more than 1.7. EFFECT: extended assortment of tubes. 7 dwg

Description

 The invention relates to the field of pipe production and can be used for the manufacture of metal-polymer pipes (MPT) with a thermally insulating coating.

 Known corrugated pipe containing an inner pipe, a corrugated outer pipe, a layer of plastic between them, while on the outer surface of the inner pipe and the inner surface of the outer pipe there are separate layers of plastic, and these separate layers of plastic attach the inner pipe and the outer pipe to each other, at least in the inner corrugations of the outer pipe, and the plastic layers on the outer surface of the inner pipe and the inner surface of the outer pipe are made of recycled foam [1].

 This design contains two layers of foamed plastic. One layer is extruded and located in the form of a continuous layer directly on the pipe, and the other layer is made in the form of protrusions, alternating depressions, and is located outside the continuous layer. Outside the protrusions and depressions is a layer of non-foamed plastic, which repeats their shape.

 In order to save weight and expensive raw materials, the plastic layers are made of recycled plastic, thus, due to the protrusions in this technical solution, the problem of reducing the consumption of materials is solved.

 A limitation of the device is the insufficiently high insulating properties, therefore, the protrusions of the porous material are covered directly with a continuous layer of plastic, and this design does not solve the problem of the possibility of bending the pipe in different directions.

 The closest is a multilayer pipe construction containing a pipe, a porous element located outside and surrounding the pipe, while the pipe has a ring stiffness higher than the ring stiffness of the porous element [2].

 The pipe in this technical solution is made of plastic and is intended for laying it underground, therefore, this technical solution indicates that the compression of the wall of the porous layer is at least 1.5% of the inner diameter of the pipe. In this case, lateral compression is considered, since the pipe must retain its shape under the influence of the weight of the soil. Therefore, in one embodiment, a rigid pipe is described comprising an PE-X inner pipe, a thin foam layer, and a metal culvert with a plastic sheath. Thus, in this embodiment, the metal pipe is located outside, and not inside the finished product and serves to give rigidity to the structure. The foam layer in this technical solution serves to provide adhesion between PE-X and a metal such as aluminum.

 The claimed device also solves a different task than in the well-known latest technical solution, namely, providing the possibility of bending the pipe while maintaining the quality of the porous layer located on the outer surface of the MPT, and improving the insulating properties of the MPT itself. To date, MPT with a thermally insulating coating as a constructive whole device has not been produced by the domestic industry, and foreign analogues of MPT with a thermally insulating coating have not been found.

 The problem solved by the invention is the improvement of the technical and operational characteristics of metal-polymer pipes and the possibility of bending them without violating the insulating coating.

 The technical result that can be obtained in the manufacture of the claimed multilayer pipe design is the expansion of the range of manufactured MPTs, the provision of technical and operational characteristics inherent in the MPT with preservation of flexibility and shape after bending to a radius of at least five outer diameters of the MPT, as well as ensuring thermal conductivity from 0, 04 to 0.1 W / m • K and sound absorption up to 26 dB to improve the operation of pipelines installed in residential premises.

To solve the problem in the well-known multilayer construction of a pipe containing a pipe, a porous element located outside and surrounding the pipe, while the pipe has an annular stiffness higher than the annular stiffness of the porous element, according to the invention, a metal-polymer pipe (MPT) made of aluminum or copper, or alloys based on them with a metal wall thickness from 0.1 to 7.0 mm with a polymer coating of its inner and outer surface with a polymer wall thickness from 0.1 to 3 mm, porous the element is made of foamed polyolefin with a density of 100 to 500 kg / m ³ , while the ratio of the outer diameter D _{pe of the} porous element to the outer diameter D _{mp of the} metal-polymer pipe is selected to be no more than 1.7.

Additional embodiments of the device are possible, in which it is advisable that:
- as the polymer coating was used low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene;
- the thickness of the polymer coating was selected from 0.9 to 1 mm with a density of 940 to 960 kg / m ³ ;
- adhesive layers were introduced, located respectively between the metal wall and the polymer coating of its inner and outer surfaces, while the thickness of the adhesive layers was selected from 0.1 to 0.2 mm with a density of 920 to 940 kg / m ³ and As the adhesive layers, a modified low linear density polyethylene — sevilen — was used;
- as the foamed polyolefin of the porous element, low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene with a wall thickness of the porous element from 4 to 22 mm was used;
- the porous element was solid.

In addition to the last option, options are possible in which
- on the outer surface of the porous element provided with protrusions alternating hollows, the outer diameter ratio D _HB projection to the outer diameter D _MAT metallopolymer tube selected in the range from 1.15 to 1.7, the ratio of diameter D _{in the} depressions to the outer diameter D of the pipe _MAT metallopolymer selected in the range from 1.1 to 1.4, and the ratio of the distance S between the protrusions to the outer diameter D _{mpt of the} metal pipe is selected in the range from 0.1 to 0.7;
- introduced a sleeve located outside the protrusions and made of polyolefin with a wall thickness of 0.4 to 2 mm with a density of 940 to 960 kg / m ³ ;
- the inner diameter D _{bp of the} sleeve is selected larger than the outer diameter D _{bb of the} protrusions, and the ratio of the inner diameter D _{bp of the} sleeve to the outer diameter D of the _{bp is} selected in the range from 1.05 to 1.3.

 In addition, the porous element can be made in the form of a spiral mounted on the outer surface of the metal-polymer pipe and provided with a sleeve.

In addition to the last option, options are possible in which:
- the spiral is made with coils of circular cross section;
- the spiral is made with turns of rectangular cross section;
- the spiral is made with a longitudinal cavity in each turn;
- spiral coils are installed in contact with each other;
- spiral coils are installed with a gap between each other;
- the ratio of the distance L between the longitudinal axes of two adjacent turns to the outer diameter D _{mp of the} metal-polymer pipe is selected in the range from 0.1 to 1.2;
- the sleeve was made of polyolefin with a wall thickness of from 0.4 to 2 mm with a density of from 940 to 960 kg / m ³ ;
- the inner diameter D _{bp of the} sleeve is selected larger than the outer diameter D _{ns of the} spiral, and the ratio of the inner diameter D _{bp of the} sleeve to the outer diameter D _{ns of the} spiral is selected in the range from 1.05 to 1.3.

 These advantages, as well as features of the present invention are illustrated by the best options for its implementation with reference to the accompanying figures.

FIG. 1 shows a cross section of a metal polymer pipe (MPT) with a continuous heat-insulating coating and with a sleeve;
figure 2 is the same as figure 1, a longitudinal section;
figure 3 is a longitudinal section of the MPT with a thermally insulating coating made with protrusions and with a sleeve;
4 is a longitudinal section of the MPT with a thermally insulating coating of a spiral and with a sleeve;
5 is a cross section of a spiral coil with a circular cross section and with a longitudinal cavity;
FIG. 6 - the same as in figure 4, from a spiral of rectangular cross section and with a gap between the turns;
FIG. 7 is a cross section of a spiral coil with a rectangular cross section and with a longitudinal cavity.

The multilayer pipe structure (FIGS. 1, 2) comprises a pipe 1 and a porous element 2. A porous element 2 is located outside and surrounds the pipe 1. The pipe 1 has an annular stiffness higher than the annular stiffness of the porous element 2. Metal-polymer pipe is used as pipe 1, made of aluminum or copper, or alloys based on them with a metal wall thickness of 3 from 0.1 to 7.0 mm with a polymer coating of its inner and outer surface with a polymer wall thickness of 4 from 0.1 mm to 3 mm. The porous element 2 is made of foamed polyolefin with a density of from 100 to 500 kg / m ³ . The ratio of the outer diameter D _{pe of the} porous element 2 to the outer diameter D _{mp of the} metal-polymer pipe was chosen no more than 1.7.

As the polymer coating can be used low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene. The wall thickness 4 of the polymer coating is selected from 0.9 to 1 mm with a density of 940 to 960 kg / m ³ .

Adhesive layers 5 can be introduced, located respectively between the metal wall 3 and the polymer coating of its inner and outer surfaces. The thickness of the adhesive layers 5 is selected from 0.1 to 0.2 mm with their density from 920 to 940 kg / m ³ , and modified low-density polyethylene, sevilen, was used as adhesive layers.

 As the foamed polyolefin of the porous element 2, low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene with a wall thickness of the porous element 2 from 4 to 22 mm are used.

The porous element 2 is made continuous (figure 2). The design may be provided with a sleeve 6 (Fig. 1, 2). Sleeve 6 performs protective and decorative functions. When performing the porous element 2 and the sleeve 6 by coextrusion, the sleeve 6 can be applied directly to the outer surface of the porous element 2 (figure 2). Therefore, the sleeve 6 can be made of polyethylene with the minimum possible thickness from 0.02 to 0.05 mm and with its density from 900 to 960 kg / m ³ . However, to improve the thermally insulating properties, the sleeve 6 is preferably made with an inner diameter greater than the outer diameter of the porous element 2 (Fig. 1), as a result of which an air gap 7 is formed and the thermally insulating properties of the device are significantly improved. In addition, the gap 7 allows you to select the distortion of the linear dimensions of the pipe 1 (MPT) when it is bent.

On the outer surface of the porous element 2 (FIG. 3), protrusions 8 alternating with depressions 9 can be made. The ratio of the outer diameter D of _the protrusion to the outer diameter D of the _MMP metal pipe is selected in the range from 1.15 to 1.7. The ratio of the diameter D _{in the} troughs to the outer diameter D _{mp of the} metal-polymer pipe is selected in the range from 1.1 to 1.4. The ratio of the distance S between the protrusions to the outer diameter D _{mp of the} metal-polymer pipe is selected in the range from 01 to 0.7. The sleeve 6 is located outside the protrusions 8 and is made of polyolefin with a wall thickness of 0.4 to 2 mm with a density of 940 to 960 kg / m ³ . The increase in the wall thickness of the sleeve 6 allows you to hide the uneven surface of the porous element 2 and to improve the appearance of the product. The inner diameter D _{bp of the} sleeve 6 is selected larger than the outer diameter D _{bp of the} protrusions 8, and the ratio of the inner diameter D _{bp of the} sleeve to the outer diameter D of _the bumps is selected in the range from 1.05 to 1.3.

 The porous element 2 can be made in the form of a spiral mounted on the outer surface of the MPT (figure 4). The spiral is made with coils of circular cross section. The coils of the spiral are installed in contact with each other. To improve the insulating properties of the spiral is made with a longitudinal cavity in each coil (figure 5).

 In addition, the spiral can be made with turns of rectangular cross-section (Fig.6). To improve the insulating properties of the spiral coils are installed with a gap 10 between each other, and the spiral is made with a longitudinal cavity in each coil (Fig.7).

The ratio of the distance L between the longitudinal axes of two adjacent turns to the outer diameter D _{mpt of the} metal-polymer pipe can be selected in the range from 0.1 to 1.2 (Fig.6). As studies have shown, this ratio is also true for spiral coils with a circular cross section.

A sleeve 6 located outside the spiral and made of a polyolefin with a wall thickness of 0.4 to 2 mm and a density of 940 to 960 kg / m ^{3 was} also introduced into the device. The inner diameter D _{bp of the} sleeve 6 is selected larger than the outer diameter D _{nc of the} spiral, and the ratio of the inner diameter D _{bp of the} sleeve 6 to the outer diameter D _{nc of the} spiral is selected in the range from 1.05 to 1.3.

 A multilayer pipe construction works (Figs. 1-7) as follows.

 The device (Fig. 1, 2) can be obtained in accordance with known methods by coextrusion methods (see, for example, the patent of the Russian Federation, B 29 C 47/02, publ. 1999) on the installation for the manufacture of MPT LT002.00.00.00.00.00.00, NPP "Mayak-93", 1998) with the addition of its extrusion head for applying a porous layer. The sleeve 6 can also be made by extrusion, and all polymer layers are made in a single technological cycle.

 The tests for various pipe sizes (Table 1) showed the possibility of bending the MPT manually without breaking the thermally insulating coating.

All tests were carried out for MPT made of aluminum, copper or easily bending alloys based on them with a metal wall thickness of 3 from 0.1 to 7.0 mm. The polymer coating of the inner and outer surfaces of the metal wall 3 had a thickness of the polymer wall 4 from 0.1 mm to 3 mm. As the porous element, material from the class of polyolefin (foamed with porophore) with a density of 100 to 500 kg / m ^{3 was used} . Studies have shown that when the ratio of the outer diameter D _{pe of the} porous element 2 to the outer diameter D _mpt MPT is greater than 1, 7, a significant warpage of the outer surface of the porous element 2 occurs due to the large values of longitudinal compression or longitudinal tension of the porous element 2 when bending the pipe by five external diameters D _MAT MAT.

 The device (figure 3) can be obtained in accordance with known methods by coextrusion methods (see, for example, patent of the Russian Federation 2126322, 29 C 47/02, publ. 1999, or patent of the Russian Federation 2142092, F 16 L 11 / 11, published in 1999) at the installation for the manufacture of MPT (Operation Manual LT002.00.00.00.00.00, NPP "Mayak-93", 1998) with the addition of its extrusion head for applying a porous layer, with a corrugator for making protrusions 8 and troughs 9 (or a simplified design of a corrugator with a single roller). The sleeve 6 can also be made by extrusion or made by some other method of a flat polymer material with its subsequent heat crosslinking.

 The test results are summarized in table. 2.

Thus, in the studied structures, the ratio of the outer diameter D of _the protrusion 8 to the outer diameter D _mpt MPT is selected in the range from 1.15 to 1.7, the ratio of the diameter D _{in the} depressions 9 to the outer diameter D _{mpt is} selected in the range from 1.1 to 1.4, and the ratio of the distance S between the protrusions 8 to the outer diameter D _{mp is} selected in the range from 01 to 0.7.

 In addition to the fact that this design facilitates the possibility of bending MPT with a lighter effort, it also allows using sleeve 6 to improve the thermal insulation properties and sound absorption due to the air gap formed in the depressions 8. The design of the patent of the Russian Federation 2142092 cannot show such thermal insulation qualities, since in it the sleeve 6 is corrugated together with the porous element 2 and placed directly on the outer surface of both the protrusions 8 and the depressions 9.

 Designs were also investigated (FIGS. 4-7). These devices can also be obtained using the installation for the manufacture of MPT (Operation Manual LT002.00.00.00.00.00, NPP "Mayak-93", 1998) with the addition of its winding head for applying the porous layer 2, made in the form of a spiral. For the manufacture of the spiral, separately made porous profiles made of round or rectangular cross section, and also made in the form of hollow tubes of round or rectangular cross section, were used.

 The test results are summarized in table. 3.

 The gap between adjacent turns (Fig. 4) may be absent without deterioration in the quality of the MPT and provide, in the entire range of MTT sizes, a simple MPT bending with insignificant average forces even for large MPT diameters and for a thick metal wall 3, because when bending MPT, the coils are easily deformed, like a bending spring.

The distance L between the turns (6) can vary widely depending on the diameter of the thread of the turn of the porous element 2 or on the thickness of the rectangular porous element 2. In addition, studies have shown that the distance L between adjacent turns can be increased compared to the distance S between the protrusions 8 for the device (figure 3), since when bending the MPT, the turns are able to move. Therefore, the ratio of the distance L between the longitudinal axes of two adjacent turns to the outer diameter of the MPT can be selected in the range from 0.1 to 1.2. (The optimal interval is for L / D _MPT from 0.2 to 0.7). By providing an air gap between the turns themselves and the sleeve 6, the heat-insulating qualities of the MPT are improved. To improve even greater thermal insulating qualities and facilitate deformability, the spiral coils can be made hollow in the form of tubes (Figs. 5, 7).

However, to carry out a spiral with a ratio of the outer diameter D _{pe of the} porous element 2 to the outer diameter D _{mpt of the} metal-polymer pipe more than 1, 7 is impractical not for reasons of destruction of the porous element 2, as was observed in the technical solutions of FIGS. 1, 2, 3, in which the porous element 2 is mounted on the outer surface MAT after its extrusion coating, and because of the fact that the spiral turns freely mounted on the outer surface of MAT, when it is bent at five D _MAT experience severe deformation, extend from the outer surface of MAT in avlivayutsya sleeve 6, which leads to warping hose 6. When operating the MAT having an outer diameter D of the porous member _pH 1.7 more than 2 • D _MAT possible destruction of the sleeve 4 in place of the pipe bend 1.

 The most successfully claimed multilayer pipe construction is industrially applicable in mechanical engineering and construction using lightweight metal-polymer pipes with a thermally insulating coating with the possibility of bending them in different directions. The obtained MPT can be used in domestic hot and cold water supply systems in individual multi-story construction, as well as in reconstruction of buildings. It is especially effective to use the declared MPT where welding is prohibited.

Sources of information
1. Patent of the Russian Federation 2142092, F 16 L 11/11, publ. 1999 year

 2. Patent of the Russian Federation 2157939, F 16 L 9/12, publ. 2000 year

Claims (18)

1. A multilayer pipe structure comprising a pipe, a porous element located outside and surrounding the pipe, the pipe having an annular stiffness higher than the annular stiffness of the porous element, characterized in that the metal-polymer pipe made of aluminum or copper is used as the pipe, or alloys based on them with a metal wall thickness from 0.1 to 7.0 mm with a polymer coating of its inner and outer surfaces with a polymer wall thickness from 0.1 to 3 mm, the porous element is made of foamed polyolefin with density from 100 to 500 kg / m ³ , while the ratio of the outer diameter D _{pe of the} porous element to the outer diameter D _{mp of the} metal-polymer pipe is selected not more than 1.7.  2. The construction according to claim 1, characterized in that the polymer coating used is low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene. 3. The construction according to claim 2, characterized in that the wall thickness of the polymer coating is selected from 0.9 to 1 mm with a density of 940 to 960 kg / m ³ . 4. The construction according to p. 3, characterized in that the adhesive layers are introduced, located respectively between the metal wall and the polymer coating of its inner and outer surfaces, while the thickness of the adhesive layers is selected from 0.1 to 0.2 mm with a density of 920 up to 940 kg / m ³ , and as the adhesive layers used modified polyethylene of low linear density - sevilen.  5. The construction according to p. 1, characterized in that the foamed polyolefin of the porous element is low-pressure polyethylene silanol-crosslinked PEH, or low-pressure polyethylene HDPE, or high-pressure polyethylene LDPE, or polypropylene with a wall thickness of the porous element from 4 to 22 mm.  6. The design according to p. 1, characterized in that the porous element is solid. 7. The construction according to p. 6, characterized in that on the outer surface of the porous element there are protrusions alternating with hollows, the ratio of the outer diameter D of _the protrusion to the outer diameter D of the _{MMP of the} metal-polymer pipe being selected in the range from 1.15 to 1.7, the ratio the diameter D _{in the} depressions to the outer diameter D _{mp of the} metal pipe is selected in the range from 1.1 to 1.4, and the ratio of the distance S between the protrusions to the outer diameter D _{mp of the} metal pipe is selected in the range from 01 to 0.7. 8. The construction according to p. 7, characterized in that the sleeve is introduced, located outside the protrusions and made of a polyolefin with a wall thickness of 0.4 to 2 mm with a density of 940 to 960 kg / m ³ . 9. The design according to p. 8, characterized in that the inner diameter D _{bp of the} sleeve is selected larger than the outer diameter D of the _nb protrusions, and the ratio of the inner diameter D _{bp of the} sleeve to the outer diameter D of the _nb protrusions is selected in the range from 1.05 to 1, 3.  10. The construction according to p. 1, characterized in that the porous element is made in the form of a spiral mounted on the outer surface of the metal-polymer pipe, and a sleeve is inserted located outside the spiral.  11. The design according to p. 10, characterized in that the spiral is made with turns of circular cross section.  12. The design according to p. 10, characterized in that the spiral is made with turns of rectangular cross section.  13. The design according to p. 10, characterized in that the spiral is made with a longitudinal cavity in each coil.  14. The design according to p. 10, characterized in that the spiral coils are installed in contact with each other.  15. The design according to p. 10, characterized in that the spiral coils are installed with a gap between each other. 16. The construction according to p. 15, characterized in that the ratio of the distance L between the longitudinal axes of two adjacent turns to the outer diameter D _{mp of the} metal-polymer pipe is selected in the range from 0.1 to 1.2. 17. The design according to p. 10, characterized in that the sleeve is made of polyolefin with a wall thickness of from 0.4 to 2 mm with a density of from 940 to 960 kg / m ³ . 18. The design according to p. 17, characterized in that the inner diameter D _{bp of the} sleeve is selected larger than the outer diameter D _{ns of the} spiral, and the ratio of the inner diameter D _{bp of the} sleeve to the outer diameter D _{ns of the} spiral is selected in the range from 1.05 to 1, 3.

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