RU2254515C2 - Method of improving heat insulation of heat pipelines - Google Patents

Abstract

FIELD: heat insulation.

SUBSTANCE: method comprises making the outer waterproofing protecting coating, which is glued to the intermediate heat insulation fiber-porous layer, by partial impregnating of the coating with a binder, solidifying the binder, and making the plastic reinforced with fibers of the intermediate layer.

EFFECT: enhanced reliability and prolonged service life.

1 cl, 1 dwg, 1 tbl

Description

The invention relates to a method for improving the quality of thermal insulation of pipelines and can be used to increase the reliability, efficiency and service life of heating systems of technical pipelines of enterprises and housing and communal services.

A known method of insulation of a heat conduit, comprising a pipe with thermal insulation on a foam-polymer base with dense inner and outer crusts with a heat-insulating middle layer. adhesive bonded to each other and the insulated pipe, while the thermo-waterproofing sheath is made thin enough to ensure vapor permeability (RU 2115058 C1, 07/10/98, Bull. No. 19).

The closest technical solution to the proposed one is a method of thermal insulation of pipelines of heating networks, consisting of a thermal insulation layer and a protective coating. Mineral wool and fiberglass cylinders are effective heat-insulating products for heating networks laid in the ducts. In methods of thermal insulation of underground pipelines of channel laying, taking into account possible dripping-liquid moisture, it is recommended to use only hydrophobized heat-insulating materials. To limit the moisture content of the fibrous insulation during overhead and underground duct laying, a protective coating of waterproofing materials is installed along the heat-insulating layer. In domestic practice, in constructions with mineral wool and glass wool insulation, fiberglass, polymer films, plaster coatings, etc. are used when laying in the channels (see "Energy Saving" 2002, No. 5, p. 43-45).

The disadvantage of these methods is the penetration of moisture into the applied composite thermal insulation, which leads to a deterioration in the quality of thermal insulation due to a significant increase in thermal conductivity when moistened and impregnated with moisture in the average heat-insulating fibrous-porous layer and, as a result, it is necessary to provide for the use of a larger calculated thickness of thermal insulation to exclude excess standards heat loss. Moisture penetration into the thermal insulation also leads to pipe corrosion and a decrease in the service life of the entire structure.

The technical result of the proposed method for improving the quality of thermal insulation is to increase the efficiency, reliability and durability of thermal insulation of the heat pipe.

This result is achieved by eliminating moisture penetration into the structure through the use of an external waterproofing layer, adhesive bonded to the middle heat-insulating layer, by partially impregnating it with a binder (resin), followed by polymerization (hardening) and the formation of plastic reinforced with fibers of the middle layer , the required thickness and mechanical properties to ensure the tightness, integrity and form stability of the whole composition, as well as having sufficient resistance resistance to mechanical damage, heat resistance, exposure to operating conditions and conditions, and preserving these properties for as long as possible (due to the use of special binder compositions), which ensures the result obtained.

A study (simulation) of specific heat loss Q (W / m) through the outer surface of 1 m of the length of the pipeline insulated with three-layer insulation with a variation of a number of factors, among which it should be noted, in particular: the outer diameter of the steel pipe D ₁ (M), the thermal operation mode of the pipelines , external diameters and thermal conductivity coefficients of the three insulation layers D ₂ , D ₃ , D ₄ , λ ₁ , λ ₂ , λ ₃ , respectively, the thickness of the external waterproofing layer δ _guide (mm) and other factors. The following is an example of the implementation of this study in the form of a table and a graphical spatial dependence for the outer diameter of the steel pipe D ₁ = 120 mm with variations in the thickness of the outer protective waterproofing layer δ _guide in the range from 2 mm to 20 mm. The variable thickness of the outer protective waterproofing layer is obtained by increasing the depth of impregnation of the middle heat-insulating fibrous-porous layer with a binder and the formation of a plastic layer reinforced with fibers of the middle heat-insulating layer after hardening (see table 1). The drawing shows a graphical spatial dependence of the specific heat loss of the pipeline Q (W / m) on the thickness of the outer waterproofing layer δ (mm) and the thermal conductivity of the average fiber-porous heat-insulating layer λ ₂ (W / m · K), from which it follows that there is an optimal the thickness range of the external waterproofing layer δ (mm) (the depth of impregnation of the middle layer with a binder), providing specific heat loss Q <56 (W / m), which is in the range 4 <δ <14 mm, which is ensured by the impregnation time and average speed Stu impregnation.

As noted above, the optimal thickness of a given waterproofing layer depends on a number of factors, among which

Table 1 Source and calculated data Q, W / m K δ _GUIDE , mm λ ₁ , W / m K λ ₂ , W / m K λ ₃ , W / m K D ₁ , m D ₂ , m D ₃ , m 1 63,615 0,203 2 0,800 0,065 0,800 0,120 0.130 0.226 2 56,478 0.180 4 0,800 0,055 0.750 0,120 0.130 0.222 3 51,531 0.164 6 0,800 0,048 0.720 0,120 0.130 0.218 4 50,158 0.160 8 0,800 0,045 0.710 0,120 0.130 0.214 5 51,775 0165 10 0,800 0,045 0.700 0,120 0.130 0.210 6 53,540 0.171 12 0,800 0,045 0.700 0,120 0.130 0.206 7 55,468 0.177 14 0,800 0,045 0.700 0,120 0.130 0.202 8 57,583 0.183 16 0,800 0,045 0.700 0,120 0.130 0.198 nine 59,915 0.191 eighteen 0,800 0,045 0.700 0,120 0.130 0.194 10 62,498 0.199 twenty 0,800 0,045 0.700 0,120 0.130 0.190 D ₄ , m D ₂ / D ₁ D ₃ / D ₂ D ₄ / D ₃ α ₂ R ₁ R ₂ R ₃ R ₄ 1 0.230 1,083 1,738 1.018 7.0 0,050 4,254 0.011 0.621 2 0.230 1,083 1,708 1,036 7.0 0,050 4,865 0.024 0.621 3 0.230 1,083 1,677 1,055 7.0 0,050 5,385 0,037 0.621 4 0.230 1,083 1,646 1,075 7.0 0,050 5,538 0.051 0.621 5 0.230 1,083 1,615 1,095 7.0 0,050 5,329 0,065 0.621 6 0.230 1,083 1,585 1,117 7.0 0,050 5,115 0,079 0.621 7 0.230 1,083 1,554 1,139 7.0 0,050 4,897 0,093 0.621 8 0.230 1,083 1,523 1,162 7.0 0,050 4,675 0.107 0.621 nine 0.230 1,083 1,492 1,186 7.0 0,050 4,448 0.122 0.621 10 0.230 1,083 1,462 1,211 7.0 0,050 4,217 0.136 0.621

distinguish: the diameter of the insulated pipe, ensuring and maintaining the necessary mechanical properties of the structure under the influence of various modes and operating conditions of the heat pipe for a long time, restrictions on the nominal overall dimensions of the pipelines, obtaining the optimal thickness of the entire composite insulation and the outer protective layer with minimizing the equivalent thermal conductivity of the multilayer composition, manufacturability as of this external waterproofing layer, and of the entire structure as a whole and for R. factors, and averages ~ 10% of the thickness of the entire insulation.

Figure 2 shows a diagram of the proposed design of the heat pipe corresponding to the proposed method. The design of the heat conduit includes a pipe 1 with a thermo-waterproofing composition, consisting of three layers of adhesive adhesive bonded to each other and an insulated pipe, in which the inner layer 2, which is tightly adjacent to the pipe, acts as a corrosion-resistant coating, followed by an average heat-insulating layer 3 based on a fibrous-porous non-woven mineral wool or glass fiber material, then a protective layer of waterproofing material 4, adhesively bonded to the middle layer, by partially impregnating it with poisonous, followed by polymerization (hardening) and the formation of plastic of the required thickness, reinforced with fibers of the middle layer, in order to exclude moisture from entering this composition, providing the necessary tightness, heat resistance, integrity and shape stability of the whole structure, which is sufficiently resistant to mechanical damage and the effects of modes and external operating conditions and preserving these properties for as long as possible (due to the use of a special binder composition ), which provides an increase in the efficiency, reliability and service life of the entire heat-insulating structure. The optimal thickness of a given waterproofing layer is assessed depending on the variation of a number of factors: the diameter of the heat-insulated pipe, ensuring the necessary mechanical properties and their preservation under the influence of operating conditions and external operating conditions, the nominal overall dimensions of the structure and the manufacturability of its manufacture, optimization of the thickness of the entire composite insulation and external waterproofing layer to minimize the equivalent thermal conductivity of three-layer insulation in order to ensure specific heat losses from the surface of the insulated pipeline (an example of the implementation of this study, see above) and other factors. A rough estimate of the average value of this thickness is ~ 10% of the thickness of the entire insulation.

Claims (2)

1. A method of improving the quality of thermal insulation, including a thermo-waterproofing composition, consisting of three insulation layers, such as an inner layer that adheres tightly to the pipe, which performs the function of a corrosion-resistant coating, followed by an average thermal insulation layer of fibrous non-woven material made of mineral wool or glass fibers and a protective coating of waterproofing material, characterized in that the external waterproofing coating, adhesive bonded to the middle layer, is made by regulating iruemoy depth impregnation medium binder layer followed by its polymerization and form a plastic layer reinforced with fibers of the middle layer. 2. The method according to claim 1, characterized in that the depth δ of impregnation of the middle layer with a binder with controlled impregnation is 4 <δ <14 mm.

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