RU2435094C1 - Procedure for manufacture of sulphate resistant heavy-weight pipe - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: procedure for manufacture of sulphate resistant heavy-weight pipe consists in covering central pipe with concrete coating. Concrete mixture with fluidity 4-8 cm by Cone of Abrams, made of sulphate resistant Portland cement m500, water, super-plasticiser, water repellent agent and barite or ore, is applied by spraying. Also, first there is sprayed the first layer of thickness a, further there is wound a reinforcing fibreglass net and the second layer is sprayed consisting of concrete mixture of thickness (0.5-1.5)a with shear between a zone of winding and zone of spraying at 1-3 m. Further, the pipe is left on a rack, till concrete mixture stiffens. A pipe is conditioned in a storage for not less, than three days to facilitate storage strength.

EFFECT: simplified manufacture and increased service life of manufactured pipe.

3 cl, 4 tbl

Description

The invention relates to pipeline technology, and in particular to methods of manufacturing ballast-coated pipes used in laying pipelines along the bottom of reservoirs or in wetlands.

A known method of manufacturing a weighted pipe, which consists in supplying the central pipe with a concrete coating by pumping it into the annular space between the pipe and the shell through an opening in the plugs, the shell being fixed to the pipe by means of centering rings (see patent RU 2257503, class F16L 1/24 published on July 27, 2005). The unreliability of this design lies in the fact that when you enter the Central pipe with supporting centering rings in the shell, which, as a rule, has deviations from the regular cylindrical shape, significant pressure is created on the surfaces of the centering protrusions in contact with the inner surface of the shell, which causes the occurrence of significant force friction, creating a tilting moment on the centering protrusions, which leads to difficulty in the movement of the polyethylene pipe and causes local buckling of spoons or even its gap. In addition, when filling the annular space with concrete mixture, the rectangular centering protrusions create significant hydraulic resistance to the movement of a viscous weighting cement-sand or concrete mixture, which causes a significant pressure drop of the mixture in front of the protrusions and behind the protrusions, which causes a tipping moment on the protrusions that can cause them to tip over with a possible rupture of the shell. Thus, the disadvantages of this method are the high material consumption, due to the need for the manufacture of the shell, insufficient reliability and resistance to aggressive environmental influences.

The objective of the invention is to remedy these disadvantages. The technical result is to simplify the manufacture and increase the life of the resulting pipe. The problem is solved, and the technical result is achieved by the fact that according to the method of manufacturing a sulfate-resistant weighted pipe, which consists in supplying the central pipe with a concrete coating, the central pipe is placed on roller bearings mounted on a movable carriage moving along the pipe axis, removable end pipes are fixed on both sides of the pipe formwork stops rotate the central pipe with roller bearings and, moving the pipe with the carriage, spray the first layer of concrete mixture with a fluidity of 4-8 see Abrams Cone of thickness a , return the carriage to its original position and wind the reinforcing fiberglass net and spray the second layer of concrete mix with a thickness of (0.5-1.5) and with a shift between the winding zone and the spray zone of 1-3 m, the concrete mix and compacted with rolls, formwork stops are removed and the pipe is left on the racks until the concrete mixture is set, after which the pipe is kept in the warehouse for at least three days to ensure storage strength, and a mixture with the following content of comp onents, wt.%:

Sulfate-resistant Portland cement m500 12-17% Water 5.5-9.5% Water to cement ratio 0.46-0.56 Superplasticizer 0.25-0.3% Water repellent 0.01-0.03% Barite ore rest

PCE polycarboxylates or the Gambit Superplast (E4) ready-mix can be used as a superplasticizer, and sodium methyl silicate as a hydrophobizing agent.

The proposed method is as follows.

In the manufacture of the central pipe, a three-layer polyethylene coating is applied to its surface, which is peeled off from the ends of the central pipe. The central pipe is placed on the roller bearings of the concrete spraying installation, which, in turn, are mounted on a movable carriage moving along the axis of the pipe. On both sides of the pipe, removable end formwork limiters are fixed, designed to prevent concrete from getting onto the ends of the pipes and form a flat end surface of the applied layer. Roller bearings begin to rotate the central tube. Simultaneously, the mechanism spraying ballast layer thickness a, and by a carriage begins moving along the pipe mechanism performing a first sprayed layer of concrete mix. When spraying concrete, one of the main characteristics is the fluidity of the concrete. A concrete mixture with a yield below 4 cm in Abrams Cone is inactive, therefore its use is ineffective. When the concrete mixture flows over 8 cm along the Abrams Cone, the concrete mixture becomes highly mobile, which is also undesirable, because it drains quickly and, as a result, uneconomical expenditure of ballast material. After spraying the first layer, the carriage with the pipe rotating on it returns to its original position and winding begins on the first layer of the applied coating of the reinforcing fiberglass. The thickness of the applied layer is adjusted by the rolling roller with a given thickness of the applied layer and adjustable pressure on the winded fiberglass mesh. Immediately after winding the fiberglass mesh, a second layer of concrete mix is sprayed with a thickness of (0.5-1.5) a . The delay in the movement of the spray carriage from the carriage along the winding of the fiberglass is 1-3 m, which is necessary for trimming the fiberglass and fixing its ends at the end of the winding layer. Excess concrete mix is removed with shovels, and the remaining concrete mix is rolled up and compacted with rolls. The finished ballast-coated pipe is placed on the shelves in the rack. Curing of the concrete mixture takes place in the rack at a temperature of + 25 ° C for 10 hours or at a temperature of + 60 ° C for 8 hours. After the concrete mixture has gained storage strength, the pipe with a ballast coating is kept in the warehouse for at least another three days.

As a concrete mixture, a mixture with the following components is used:

Sulfate-resistant Portland cement m500 12-17% Water 5.5-9.5% Water to cement ratio 0.46-0.56 Superplasticizer 0.25-0.3% Water repellent 0.01-0.03% Barite ore rest

PCE polycarboxylates or the Gambit Superplast (E4) ready-mix can be used as a superplasticizer, and sodium methyl silicate as a hydrophobizing agent. The specified composition has increased sulfate resistance and is resistant to the aggressive effects of the aquatic environment.

Thus, the ballast-coated pipe made according to the proposed method consists of a central pipe with an anti-corrosion coating applied to it and a ballast material that is formed on the conductive pipe by gunning (spraying). Inside the ballast material, a fiberglass mesh was used as a reinforcing structure, which allows to increase the thickness of the concrete layer without the risk of shedding, is durable and slightly susceptible to destruction in the aquatic environment. The fiberglass is applied by uniformly spiral winding it onto a conductive pipe with an overlap of 3-6 cm. The reinforcing fiberglass is winded after spraying the first layer of a protective coating with a thickness of a (optimal thickness 15-50 mm). The second coating layer is sprayed onto a layer of reinforcing fiberglass mesh with a thickness of (0.5-1.5) a (average 15-60 mm). The total thickness of the concrete coating is 30-110 mm, depending on the need.

For different pipe sizes and operating conditions, a different fiberglass mesh is used. When reinforcing pipes ⌀820-1420 mm, it is necessary to use an armored glass mesh, the characteristics of which are given in Table 1. The specified fiberglass mesh is also used on pipes of smaller diameters, if there are design requirements for increased strength of the concrete coating, or heavy or especially heavy concrete is used. A fiberglass mesh of 6 mm × 8 mm (armored fiberglass mesh) is characterized by increased tensile strength and alkali resistance. When reinforcing pipes with a diameter of less than 820 mm, a fiberglass mesh of the SST-B-TRANSET type is used, the characteristics of which are given in Table 2.

The test results of the concrete mixture are shown in table 3 and table 4. The properties obtained demonstrate the advantages of the proposed method.

Table 1 Technical Parameters of Armored Fiberglass Mesh The mesh cell size in the clear, mm 6.0 × 8.0 (6.0 × 6.0) Mass per unit area, g / m ² 320 ± 10% Width cm 100 + 2 / -1 Length m 50 ± 8% Thread thickness not less than, mm 0.36 Breaking load, N / 5 cm, not less than: - based 3250 - by duck 3950

table 2 Technical Parameters of SST-B-TRANSET Glass Mesh SST-B 3.4 × 3.4-120 (45) -Transet The weight per unit area of not less than g / m ² 120 Breaking load (along / across) not less than, N / 5 cm 1000/1000 Elongation at break (along / across) no more than,% 3/3 Mass fraction of substances removed by calcination not less than,% 10 The size of the side of the square of cells, mm 3.4 Roll Width, m 0.45

Table 3 Concrete mixes Components and Relationships Content in wt.% one 2 3 Composition according to patent RU 2257503 Cement 12 fifteen 17 17 Water 5.88 8.4 9.5 5.1 The ratio of the mass of water to the mass of cement 0.49 0.56 0.56 0.3 Superplasticizer - polycarboxylate 0.25 0.3 0.3 - Water repellent - sodium methyl silicate 0.01 0.02 0,03 - Aggregate - barite ore: 81.37 75.72 72.61 77.6 - coarse fraction over 5 mm to 25 mm; 11.6 fourteen 16 Gravel 44 - fine fraction over 0.16 mm to 5 mm; 80 72 70 Quartz sand 34 and barite 14 - a very fine fraction of more than 0.01 μm to 160 μm - barite ore powder. 8.4 fourteen fourteen 8 The ratio of the masses of the components of a very small fraction to a large fraction of 1 m ³ 0.72 one 0.875 0.18

Table 4 Concrete Mix Properties Properties Property Values 2 3 four Composition according to patent RU 2257503 The mobility of the injected ballast material, determined according to GOST 10181-2000 19 25 25 9 Density, kg / m ³ 3300 3230 3100 1480 Compressive strength, MPa 46 48 fifty 40

Claims (3)

1. A method of manufacturing a sulfate-resistant weighted pipe, comprising supplying the central pipe with a concrete coating, characterized in that the central pipe is placed on roller bearings mounted on a movable carriage moving along the pipe axis, removable end formwork end stops are fixed on both sides of the pipe, the central one is rotated the pipe with the help of roller bearings and, moving the pipe with the help of the carriage, spray the first layer of concrete mixture with a fluidity of 4-8 cm along the Abrams cone of thickness a, return the carriage to the original position and make the winding reinforcing fiberglass and spray the second layer of concrete mixture with a thickness of (0.5-1.5) and with a shift between the winding zone and the spray area of 1-3 m, the concrete mixture is rolled and compacted with rolls, the formwork stops are removed and the pipe is left on racks until the concrete mixture sets, after which, to ensure warehouse strength, the pipe is kept in the warehouse for less than three days, moreover, a mixture with the following components is used as concrete mixture:
Sulfate-resistant Portland cement m500 12-17% Water 5.5-9.5% Water to cement ratio 0.46-0.56 Superplasticizer 0.25-0.3% Water repellent 0.01-0.03% Barite ore rest 2. The method according to claim 1, characterized in that PCE polycarboxylates or the prepared mixture “Gambit Superplast (E4)” are used as a superplasticizer. 3. The method according to claim 1, characterized in that sodium methyl silicate is used as a hydrophobizing agent.