WO2016093716A1

WO2016093716A1 - Thermal insulation for hot or cold media-carrying pipelines

Info

Publication number: WO2016093716A1
Application number: PCT/PL2015/000195
Authority: WO
Inventors: Piotr CHUPTYŚ
Original assignee: Allsetpro Spółka Z Ograniczoną Odpowiedzialnością
Priority date: 2014-12-10
Filing date: 2015-12-03
Publication date: 2016-06-16
Also published as: PL225285B1; DE112015005542T5; WO2016093716A8; PL410477A1

Abstract

The subject of the invention is thermal insulation for pipelines protecting them from loss of heat or cold when carrying heating, cooling, and other industrial and utility media characterised in that it has: a first insulation layer (2) made of aluminium foil or metallized foil with thickness g = 0.04 mm and resistant to infrared radiation (IR), connected detachably or permanently with spacing pins (3), lower ends of which adhere to outer surface of the insulated pipeline's steel pipe (1) forming this way an air gap (4) between thermal insulation and the pipe, or the first insulation layer (2) adheres directly to outer surface of a structure (11) comprising spacing battens (11') interconnected with each other by means of annular elements (12), said structure being mounted of outer surface of said steel tube (1) also forming this way an air gap (4) between the pipe and said first insulation layer; the second insulation layer (6) adjacent to the first insulation layer (2) comprising a pack of several layers of insulating plastic film bubble wrap adhering loosely to each other or glued together by means of adhesive (5) resistant to high temperatures, with bubbles of cellular structure of the wrap filled with a mixture of air and argon and bubble cells (6') pointing towards the insulated steel pipe (1); and an outer layer (7) surrounding and adhering to the second insulation layer (6), said outer layer being made of a plastic resistant to operation of ultraviolet (UV) radiation and variable climatic conditions with ends connected to each other by means of the scarf joint and topped additionally by means of tape (8) attached to its upper surface.

Description

Thermal insulation for hot or cold media-carrying pipelines

The subject of the invention is thermal insulation for pipelines carrying hot or cold media, especially for overground heat distribution pipelines seated on supporting structures, to be used for shielding pipes carrying heating, cooling, and other hot or cold industrial or utility media.

Insulated steel pipes are used commonly for transporting hot fluids in industrial supply systems and conveying hot water in central heating systems at temperatures of up to 130°C reaching 140°C in winter season and consequently, not only the insulated pipe but also the insulating material must be capable to withstand such temperatures for a long period of time without deterioration of its insulating properties caused by presence of heat stress forces. The same applies to pipelines transporting hot oil or steam temperature of which can exceed 150°C.

Description of Polish patent application P-295995 teaches a thermally insulated pipe and other pre-insulated pipes used in the industrial practice with a two-layer lagging, typically in the form of a combination of mineral wool layer and a plastic foam adhering to each other as a result of which, both during the process of forming the insulation as such and in the course of heat transfer from the medium through the wool wrapping, a degradation of the foam structure occurs at the contact of the materials resulting in development of pits and deformations of various types, diversification of the heat conduction coefficient, and additional heat losses along the whole medium transportation route.

Description of Polish patent application P-347877 reveals a method of manufacturing a compact segmented thermal insulation, especially for heat distribution or cooling media pipelines, consisting in that out of the construction site, half-cylinder segments of the pipeline protective shell are prefabricated and the segments are provided with mounting lugs on their inner surfaces. Next, the inner surfaces of the shells are covered with a layer of thermal insulation, and spacing elements are distributed along the pipeline perimeter. Then, said half-cylinder insulation segments of the protecting shell with a layer of thermal insulation material are mounted on the spacing elements, creating thus a thermally insulating air gap, and finally, the half-cylinder segments are joined longitudinally and the adjacent pipe- shaped segments of the insulation shells constructed this way are joined one by one in their face planes. From description of Polish patent PL204760 known is a method of providing insulation to pipelines with the use of an outer casing consisting in that at first, at least three spacing elements are mounted to the steel pipe's outer surface in parallel to the pipe axis, and then rubber rings in the form of tori filled with a thermo -insulating material, preferably mineral wool, are pulled over, one by one, onto the pipe, and finally side surfaces of the rubber rings are glued together creating thus a hydro- insulating partition.

Description of Polish patent application P-343806 reveals a compact segmented thermal insulation, especially for heat distributing and cooling media-carrying pipelines, characterised in that between the outer surface of the protected pipeline and the inner surface of the insulation material layer an air gap is formed by mounting axially oriented spacing/supporting elements on the pipe perimeter along the whole length of the pipeline. Moreover, the inner surface of the insulation layer is provided with a stiffening layer bound permanently to the insulation material layer, whereas the expansion gaps created along faces of neighbouring segments of the insulation layer are filled with an insulation material.

Further, description of the invention granted Polish patent PL218046 teaches thermal insulation for pipelines, especially overground heat-distributing pipelines on supporting structures, used to also shield and insulate pipes of other pipelines carrying heating and cooling media for both industrial and other purposes, composed of segmented sections and characterised in that the pipeline supports are provided with thermal insulation, preferably in the form of segments split vertically in the plane perpendicular to the pipeline axis with preferably tee-shaped cross-section, having angular or radial recesses at points of contact with the pipeline corresponding to the pipeline outer diameter and joined with elements of the insulation lagging or recesses in segmented insulation sections. Both components of the insulation cover and segmented insulation sections wrapping the pipeline are provided with spacing elements separating the outer surface of the pipeline from the insulation, whereas elements of the cover and segmented insulation sections wrapping the pipeline and lateral thermal insulation components of the pipeline supports are joined with each other.

The objective of the present invention is to develop a structure of compound insulation components for heat or cold-transporting pipelines, especially heat distribution pipelines, with simple and compact design allowing to install the insulation components on steel pipes of pipelines that need to be insulated. A further objective of the invention is to provide such layers of the thermal insulation for pipelines which will be resistant to both ultraviolet (UV) radiation and variable atmospheric conditions allowing at the same time to decrease significantly the temperature between the insulated pipe and the insulation layers surrounding it, suppress vibration of the pipe, and facilitate the process of removing the layers from the pipe.

The essential idea of the revealed technical solution of thermal insulation for shielding and insulating pipes carrying heating, cooling, and other industrial and utility media consists in that it has a first insulation layer made of aluminium foil or plastic film with thickness g = 0.04 mm resistant to infrared radiation (IR) joined detachably or permanently with a plurality of spacing pins, ends of which adhere to outer surface of the pipeline's insulated steel pipe, forming thus an air gap between the pipe an the thermal insulation layer, or the first insulation layer adheres directly to upper surface of the structure of spacing battens interconnected with each other by means of annular elements installed on outer surface of said steel pipe, also forming an air gap between elements of the structure. A second insulation layer adjacent to said first insulation layer is a pack of several layers of insulating plastic bubble wrap with cellular structure filled with a mixture of argon and air, with the layers loosely adhering to each other or glued together by means of an adhesive resistant to high temperatures and with bubbles pointing at the insulated steel pipe. Further, the second insulation layer is surrounded by an outer insulation layer made of a plastic resistant to infrared (IR) radiation and variable weather conditions, ends of which, connected to each other by means of the scarf joint, are topped additionally by means of a plastic tape. The main insulation layer adheres favourably directly to the top surface of the structure of spacing battens interconnected with each other by means of annular elements seated on the outer surface of the insulated pipeline's steel pipe, and is shielded from outside with a layer made of aluminium foil or a metallized plastic film which in turn is shielded by an outer layer made of a plastic, whereas layers of the pack of the insulation bubble wrap forming said main insulation layer have a closed cellular structure with wall thickness ranging from 5.0 μπι to 5000 μιη and are made of a plastic resistant to variable temperatures in the range from -80°C do 400°C with cells filled with atmosphere containing argon in the amount of 0.5-100% by volume, whereas width of the air gap depending on function and diameter of the insulated steel pipe is h = 1.0-100mm. The structure of several spacing battens distributed preferably evenly along perimeter of the insulated steel pipe and oriented radially towards and parallel to its main axis, has ends of the battens interconnected detachably by means of detachable annular elements so that their upper surfaces are flush with upper outer surfaces of the battens.

Creation of the gas (air) gap between the steel pipe being insulated and the surrounding layer of aluminium foil or a metallized plastic film by providing spacing pins attached to the film or the foil and adhering to the pipe surface allowed to lower significantly the temperature at the point of contact with the pipe, and introduction of spacing components in the form of pins or battens made of plastic, metal alloy, or ceramic material in the gap has resulted in significant damping of vibrations occurring in the pipe. Further, making the second layer out of aluminium foil or a metallized plastic film allowed to reduce significantly the effect of infrared radiation (IR) on the installed insulation material and increase the insulation power of the partition as the whole. Moreover, employing a successive third layer with cellular structure and bubble wall thickness ranging from 5.0 μιτι to 5000 μπι made of a plastic resistant to high temperatures, improved significantly the value of the insulation's thermal conductivity from 0.025 W/(m,K) in case of air to 0.017 W(m.K) in case of using argon to fill cells of the insulation layer. Among further merits of the invention it should be mentioned that when closing (wrapping) the insulation layer onto the layer made of aluminium foil, a significant portion of atmospheric air is removed from the insulation, and closed cells closely adjacent to each other reduce significantly the convection losses and permeability of the insulating structure to liquid water and water vapour. Moreover, individual layers with cellular structure positioned with respect to each other in both irregular and regular way formed a very good thermal insulation and vapour barrier, while positioning the cellular wrapping layers with the cells pointing at the insulated pipe allowed to increase significantly the concentration of bubbles per unit area resulting from wrapping them around curved surfaces.

The subject of the present invention is shown in the drawings representing different example embodiments of the invention without limiting the scope of the latter to example embodiments presented in the figures, of which Fig. 1 shows the first example embodiment of the thermal insulation for a segment of heating pipeline, in the perspective view, with vertical cross-section of the steel pipe and its insulating layers; Fig. 2— the same thermal insulation in the front view facing vertical cross-section of the pipe along line A-A; Fig. 3— the insulation layer of aluminium foil in a developed state provided with four rows of spacing pins attached to the foil by means of clip elements, in the top view; Fig. 4— the same insulation layer of aluminium foil in vertical cross-section along line B-B; Fig. 5— the same insulation layer in a developed state, also provided with four rows of spacing pins but attached to the foil by means of an adhesive, in the front view; Fig. 6— the same foil insulation layer surrounding the insulated steel pipe forming thus an air (gas) gap (layer) in the perspective view; Fig. 6

— a single insulation layer of bubble wrap with cellular structure in a developed state, in the bottom view; Fig. 8— the same layer in vertical cross-section along line C-C; Fig. 9

— a second example embodiment of the same pipeline thermal insulation with ten layers of bubble wrap foil insulation put on each other and forming two packs of such layers glued together in the front view with respect to vertical cross-section of the insulated pipe; Fig. 10— a pack made of five layers of plastic bubble wrap glued together by means of an adhesive, in vertical cross-section along line C-C of Fig. 2; Fig. 11— a third example embodiment of thermal insulation for a heating pipeline comprising a pack of five layers of insulating bubble wrap in which, instead of foil or film layer provided with spacing pins, a structure of four spacing battens interconnected with each other by means of two-piece annular elements was used, in the vertical cross- section; Fig. 12— the same thermal insulation but comprising ten layers of insulating bubble wrap, in vertical cross-section; Fig. 13— a fourth example embodiment of the thermal insulation in which the pack of five layers of insulating bubble wrap is placed directly on the structure made of four spacing battens, wrapped in an insulation layer made of aluminium foil and a shielding layer made of a plastic in vertical cross-section; Fig. 14— the structure of four spacing battens interconnected with each other by means of separate annular elements seated on the insulated pipe, in the perspective view; Fig. 15— detail "S" of Fig 14 showing two semi-annular elements joined by means of their tongues and grooves forming an annular element interconnecting the spacing battens, in the perspective view; and Fig. 16— detail "T" of Fig. 14 showing the same semi-annular elements joined by means of side lugs and pins or bolts.

The heat insulation for a pipeline made of steel pipes 1 with diameter d = 30 cm, a segment of which is shown in Figs. 1-8, comprises: a first insulation layer 2 made of aluminium foil with thickness g = 0.04 provided with four rows of plastic spacing pins 3 lower ends of which adhere to outer surface of the insulated steel pipe 1, with a thermally insulating air gap 4 with thickness h = 1 mm formed between them; the second insulation layer 6 adhering to said first layer and comprising at least one pack of five layers 6 of plastic insulating bubble wrap with cellular structure filled with a mixture of argon and air and with bubbles 6' pointing at the insulated steel pipe 1, loosely placed on each other or glued together by means of an adhesive 5 resistant to high temperatures of the silicone type; and an outer layer 7 shielding the inner layers, made of a plastic resistant to infrared (IR) radiation and variable weather conditions, ends of which, connected to each other by means of the scarf joint, are topped additionally by means of plastic tape 8 attached to them. Layers 6 of the bubble film insulation pack have a cellular structure with wall thickness ranging from 5.0 μηι to 5000 μm and made of a plastic resistant to variable temperatures within the range from -80°C to +400°C with cells filled with atmosphere containing argon in the amount of 0.5-100% by volume.

In another example embodiment of the insulation (not shown in the figures), on a steel pipe with diameter D = 1 m a layer made of metallized plastic film with thickness g = 0.04 mm was used and the created air gap 4 had thickness h = 100 mm.

Both the layer of aluminium foil and this of metallized plastic film 2 with length L has width U = πD, i.e. equalling the outer circumference of the steel pipe 1 with outer diameter D along which, on the whole of its length, tubular spacing pins 3 are attached to the foil by means of clips 9 at distances π D/4and πD/8 with respect to each other forming thus rows remaining at the constant distance πD/4 from each other after wrapping the foil around the steel pipe 1 separated by L\ = 25 cm along the whole length L of the film or foil layer. In the embodiment variant with a metallized plastic film shown in Fig. 5, spacing pins 3 are fixed to the film by means of adhesive 10.

Further, in a variation of thermal insulation for pipeline made of steel pipes 1 shown in Fig. 11, instead of aluminium foil or metallized plastic film 2 provided with spacing pins 3 creating a thermally insulating air gap 4 between the foil or film and surface of the insulated steel pipe 1, a structure 11 was employed comprising four spacing battens 1 1 ' interconnected with each other by means of annular elements 12 so that their upper outer surfaces 13 are flush with upper outer surfaces 14 of the battens. The outer surface of the structure adheres to a surrounding layer of aluminium foil 2, while lower (inner) surfaces of spacing battens 11 adhere to outer surface of the insulated steel pipe 1 forming this way a thermally insulating air gap 4 between the pipe and the layer of the thermally insulating material. The spacing battens 11 ' adhering to outer surface of the insulated steel pipe 1 are oriented radially towards and longitudinally parallel to the axis of the pipe, and are distributed symmetrically with respect to each other on perimeter of the pipe to be insulated. Annular elements 12 are composed of two semi-annular elements 15 and 16 which are joined by means of grooves 17 and tongues 18 forming this way a monolithic ring 12, whereas each of the spacing battens 11 has rectangular recesses 19 on its upper surface 14 to accommodate semi-annular elements 15 and 16. In another embodiment of the annular elements 12, both semi-annular elements 15 and 16 are provided with lugs 20 of their outer side with holes 21 for pins 22 joining these semi-annular elements to form an annular element 12, whereas in another example embodiment (not shown in the figures), bolts were used instead of pins 22.

Fig. 13 shows another example embodiment of thermal insulation but to be installed on pipelines carrying cold media made of steel pipes 1 with structures 11 of four spacing battens 1 Γ interconnected with each other by means of annular elements 12, where the thermal insulation comprises an insulation layer 6 composed of five layers of plastic bubble wrapping with cellular structure filled with a mixture of argon and air and bubbles 6' also pointing at the steel pipe 1, and the insulation layer 2 made of aluminium foil layer wrapped around layer 6, shielded by means of an external layer 7 made of a plastic resistant to infrared (IR) radiation and variable weather conditions, ends of which, connected to each other by means of the scarf joint, are topped additionally by means of plastic tape 8 attached to its ends.

Claims

Patent claims

Thermal insulation for pipelines carrying hot or cold media for shielding and insulating pipes carrying heating, cooling, and other industrial or utility media, comprising several layers of insulating materials surrounding pipes of said pipelines shielded in a protection shell, whereas between the outer surfaces of the pipes and the first layer of the insulating material an air gap is formed by means of providing a plurality of supporting and spacing elements oriented axially along circumference and the whole length of the insulated pipe characterised in that the first insulation layer (2) made of aluminium foil or metallized plastic film with thickness g = 0.04 mm and resistant to radiation (IR) is joined detachably or permanently with a plurality spacing pins (3) lower ends of which rest to outer surface of the insulated pipeline's steel pipe (1) forming this way an air gap (4) between the pipe and the insulation layers, or the first insulation layer (2) adheres directly to the outer surface of a structure (11) formed by spacing battens (1 Γ) interconnected by means of annular elements (12) and resting on outer surface of the steel pipe (1), also creating an air gap (4) between components of said structure, whereas the second insulation layer (6) adjacent to this first insulation layer (2) is a pack of several layers of plastic insulating bubble wrap with cellular structure filled with a mixture of argon and air with bubbles (6') pointing at the insulated steel tube (1), with the wrap layers loosely adhering to each other or glued together by means of an adhesive (5) resistant to high temperatures; and an outer layer (7) surrounding and adhering to the second insulation layer (6), said outer layer being made of plastic resistant to ultraviolet radiation (UV) and variable climatic conditions with ends joined with each other by means of a scarf joint and topped additionally by means of tape (8) attached to its upper surface.

Thermal insulation according to claim 1 characterised in that the insulation layer (6) adheres directly to the upper surface of the structure (11) of spacing battens (1 Γ) interconnected with each other by means of annular elements (12) seated on outer surface of the insulated pipeline's steel pipe (1), and another insulation layer (2) made of aluminium foil or metallized plastic film adheres on its inner side to the insulation layer (6) and is covered on its outer side with an outer layer (7).

Thermal insulation according to claim 1 characterised in that thickness of the air gap (4) depends on function and diameter D of the insulated steel pipe (1) and amounts to H = 1.0-100 mm.

Thermal insulation according to claim 1 characterised in that layers of the pack made of insulating bubble wrap (6) have a closed cellular structure with wall thickness ranging from 5.0 μιη to 5000 μm and are made of a plastic resistant to variable temperatures in the range from -80°C do 400°C with cells filled with atmosphere containing argon in the amount of 0.5-100% by volume.

Thermal insulation according to claim 1 characterised in that the structure (11) consists of several spacing battens (11') distributed evenly along perimeter of the insulated steel pipe with the diameter D and oriented radially towards and parallel to its main axis, whereas ends of the battens are joined detachably with each other be means of detachable annular elements (12) so that outer surfaces (13) of the elements are flush with upper outer surfaces (14) of the battens.