SU929019A3 - Heat-insulated pipeline for underground conveyance of hot water - Google Patents

Abstract

The large-diameter pipe is covered with a thickness of plastic foam which tapers conically away to zero thickness at each end of each length of pipe. The foam lies inside a sheathing which is retalively rigid along the cylindrical length, but elastic over the conical sections: this allows for movement in the foam when the hot central pipe expands while the cool sheathing stays fixed. Pref. the foam, made by dusting a foaming material, such as polyurethane, over the pipe, has a density of 80-120 kg/m3, and is denser at the surface than in the middle; the expanding section is of rubber, clamped round the pipe. The sheathing may consist of a spiral of bitumen (or bitumen-and-elastomer)-impregnated tape with a non-woven reinforcement and with ridges round to hold the buried pipe stable in the ground; alternatively, it may be a sprayed-on layer of non-cellular polyurethane. The spigot and socket ends of the pipe are both covered with heat-resisting plastic.

Description

(5) HEAT-INSULATING PIPELINE FOR UNDERGROUND TRANSPORTATION OF HOT WATER

one

The invention relates to the thermal insulation of pipelines and may find application in various areas of the national economy.

A heat insulation pipe is known, the coating of which contains flexible hollow elements wound on a pipe.

The disadvantage of this pipeline is the unreliable insulation of the junction of the two pipe sections.

A heat insulating pipeline is also known, which contains an inner metal pipe, a heat insulating layer of foam plastic, located around it, attached to it and surrounded by an outer protective layer, which consists of an average casing extended at each end by a shell fixed on the inner pipe 2.

However, this pipeline is characterized by insufficient reliability of operation due to the impossibility /

thermal contraction of the elongation of the inner tube when the temperature of the transported medium changes.

The aim of the invention is to improve. 5 ensures reliable operation by allowing thermal compression and elongation of the inner tube. The goal is achieved by the fact that the heat insulating layer is adhesively bonded to the protective layer, and each casing is made of sheet rubber and secured to the casing, which is formed by a tape of bitumen or batch of bitumen with an elastomer with 15 nonwoven reinforcement.

FIG. 1 shows a pipeline, a longitudinal section; in fig. 2 - sheet of pipe joint, longitudinal section.

Claims (2)

The thermal insulation pipe 20 comprises an inner metal pipe 1, made, for example, of ductile iron with an internal joint 2, made, for example, of cement mortar. Thermally insulated layer 3 is applied to tduub 1 3. adhesively adhered to it, made of polyurethane foam and having a thickness of from 30 to 50 mm. The heat insulating layer 3 is surrounded by a protective layer 4 consisting of bitumen or a mixture of bitumen with an elastomer with a non-woven reinforcement, for example glass fiber. On the protective layer, fixing protrusions 5 can be made, preferably made by forming acute-angled protuberances, embedded in the ground during the laying of the pipeline. The protective layer 4 covers the entire length of the pipe with the exception of the joint ends 6 and 7. On one of the pipes 1, the end surface 8 of the insulating layer 3 is made conical. This surface 8 is covered with a casing 9, one end of which is fixed under the layer k, and the other end is attached to the pipe 1 by means of, for example, gluing or a clamp 10. The casing 9 is made mainly of rubber sheet. Formed on one of the ends 7 of the pipe 1, the socket is covered with a protective sheath 11 made of antifriction material, for example, fluorine polymer. An annular groove 12 for mounting the sealing element 13 is formed on the inner surface of the socket. The other abutting end 6 of the pipe is also covered with a protective sheath k made of antifriction lacquer material. The pipeline is assembled in the following sequence. The inner coatings 2, the heat insulating layer 3 and the protective layer are applied to the pipes 1. Protective shells 11 and 1 are applied to the ends of pipes 7 and 6, with one end of which case 9 is fixed under the layer and the other is glued to pipe 1 or clamped with clamps 10. A sealing element 13 94 is placed in the groove 12. The pipeline is laid in the ground. When the temperature of the medium in the pipeline changes, for example, when the temperature of the pumped hot water changes, the pipes 1 are able to move relative to each other during temperature compression or elongation. The protrusions 5 securely fix the pipeline sections in the ground. Such an embodiment of the pipeline makes it possible to increase the reliability of its operation by allowing thermal compression or elongation without disturbing the outer coating and loss of tightness. Claims of Invention Thermal Insulation Pipeline for underground transportation of hot water containing an inner metal pipe, a heat insulating foam layer located around it, attached to it and surrounded by an outer protective layer which consists of an average casing extended at each end by a shell fixed on the inner pipe, characterized in that, in order to increase the reliability of operation due to the possibility of thermal compression and extension of the inner pipe, the heat insulating layer gezionno connected with the protective layer, and each shell is made of a rubber sheet and is fixed on the casing, which is formed from a ribbon of bitumen or bitumen mixture with an elastomer to the nonwoven reinforcement. Sources of information, rintye taken into account during the examination 1. The author's certificate of the USSR, cl. F 16 L 59/00, 19b9. 2.Patent UK No. 1083399 cl. F 2 P, pub. 19b7.