DD221809A1 - METHOD OF EMBEDDING AND INSULATING UNDERGROUND PIPES - Google Patents

Abstract

The invention relates to a method for embedding and insulating pipes to be laid underground, in particular pressure and temperaturfuehrenden pipes, by wrapping with a heat-insulating and corrosion-protective embedding mass. It is a cost-effective and at the same time to high operating times of the pipeline leading method to be created their wrapping by using electrostatic precipitator as the chemical and physical properties are used to adjust the strength, the heat insulation and Wasserundurchlaessigkeit the embedding mass. To form the embedding mass, an extruding electro filter ash water suspension having a p H value of 11 is prepared and introduced, the water uptake capacity of the ash is selected, which has a CaO content of 12%, such that with the final cure a Prismendruckfestigkeit the embedding mass of 2.5 N / mm 2, a thermal insulation of 0.1 W / m K and a Darcy water impermeability of KF 10 7 can be achieved. In buried pipelines, the substrate and / or the lateral boundaries of the free space provided for the embedding mass are covered with a layer of rock-based building material 4 mm and slurried with the ash-water suspension. figure

Description

Field of application of the invention

The invention relates to a method for embedding and insulating pipes to be laid underground, in particular pressure and temperature-carrying heating pipes. .

Characteristic of the known technical solutions

In the underground laying of pipelines, a distinction is made between the sewer laying and the direct underground laying.

Methods of direct burial are:

Casing method, casting method and pouring method (Munser, H .: district heating supply, VEB German publishing house for primary industry, Leipzig, 1980, p 149 ff). It is a method for insulating and embedding underground to be laid, a hot medium-carrying pipelines by their wrapping with a heat-insulating and Korrossionsschützenden bituminous embedding mass known in which the embedding mass consists of a 40 to 70 percent by volume bitumen and 30 to 50 percent by volume of perlite-containing dry mixed granules , This granulate is loosely filled around the pipe and then melted down by heat release of the hot medium flowing through the pipe to a compact embedding block (DD 131406).

The following disadvantages are associated with this method:

- For the production of the mixed granulate bitumen is required as expensive starting material,

- The method is unsuitable for pipelines of large nominal size, since a heat transfer to the outermost layers hardly takes place, ':': -. '

- elaborate cover of the top (tar paper, flame treatment),

- high heat losses,

- For the applications piping, the low-temperature heat transport are provided, unsuitable. - overall high investment costs. ,

In a .other process for producing a hydrophobic bulk insulating material for buried heating pipelines is in a hot mixing boiler, a dust-free mineral component, eg. As electrostatic filter ash, introduced, heated and mixed with introduced through nozzles bitumen and discharged (DD71672). Again, expensive bitumen is the main material for the production of insulating material. The ash merely serves as filler for the bitumen. The bulk material must be produced in special boilers. '.

Object of the invention

The aim of the invention is a cost-effective and at the same time to high operating times of the pipeline leading method of their wrapping with a thermally insulating and corrosion-protective embedding mass.

Explanation of the essence of the invention

The invention has for its object to provide a method for insulating and embedding underground to be laid pipes with a heat-insulating and Korrossionsschützenden embedding mass, in which the chemical and mechanical properties of the electrostatic filter bags used to adjust the strength, thermal insulation and Wasserundürchlässigkeit be used.

This is achieved in that the formation of the embedding mass is prepared and introduced a curing electrofilter ash - water suspension having a pH> 11, in which the added amount of water greater than or equal to the water absorption -bzw. binder strength is selected which has a CaO content> 12%, such that with the final curing a Prismendruckfestigkeit the embedding mass of> 2.5 N / mm ² , a thermal insulation of λ <0.1 W / m ⁰ K. and a water impermeability according to Darcy of K _F <10 " ^7. For buried pipelines, it is expedient if the substrate and / or the lateral boundaries of the free space provided for the embedding mass are provided with a dense rock-building material layer, eg of pebbles, gravel Or grit, covered with a grain size> 4mm and smoother with the ash-water suspension.

In a further embodiment of the invention, a layer of rock building materials is applied and purged with the ash / water suspension after the solidification of the introduced enclosure for producing a supporting, water-impermeable housing

 The wrapping fulfills the following functions:

- protection against external corrosion, as water-repellent, '

- thermal insulation,

- internal pressure resistance, ';

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It is achieved a high water-impermeable upper layer with high load capacity, which is passable without additional effort. The internal pressure resistance of the enclosure leads with appropriate design and implementation of the method for reducing (minimizing) the required pipe wall thickness or in extreme cases after wear (by internal corrosion) • for pipe replacement. The expansion behavior of the pipelines must be taken into account by the provision of expansion joints.

embodiment

The detailed explanation is made with reference to the drawing, which schematically shows an embedded buried pipeline according to the invention in section.

The pipeline 1 is surrounded by an embedding mass 2, which is formed from an ash-ZWassersuspension and after the final curing has a water impermeability of K _F <10 ~ ⁸ and a thermal insulation of λ <0.1 W / m ° K. This embedding compound 1 is bounded by a layer 3 consisting of rock waste chippings> 4 mm, which is purged with the ash / water suspension. The conclusion forms a load-bearing, water-impermeable upper layer 4 with rock building materials as a scaffold, which is ausgelämmt with an ash-ZWassersuspension. The structure and the composition are designed so that the upper layer has a load capacity> 50 N / mm ² , so may be designed as a road or footpath.

Claims (3)

-2- 260687 4 Invention claims: A process for embedding and insulating pipes to be laid underground, in particular pressure and temperature-carrying pipelines, by enveloping them with a heat-insulating and anti-corrosive embedding mass, characterized in that a hardening electro-filter ash water suspension having a pH> 11 is prepared to form the embedding mass and in which the added amount of water is greater than or equal to the water absorption capacity of the ash, which has a CaO content of> 12%, such that with the final hardening a Prism pressure strength of the embedding mass of> 2.5 N / mm ² , a thermal insulation of λ <0.1 W / m ⁰ K and a water permeability according to Darcy of K _F <10 ~ ⁷ can be achieved. 2. The method according to item 1, characterized in that in buried pipelines, the ground and / or the lateral boundaries of the space provided for the embedding mass with a dense rock material layer, e.g. of pebbles, gravel or chippings, covered with a grain size> 4mm and slurried with the ash-water suspension. 3. The method according to item 1 or 2, characterized in that applied after the solidification of the introduced envelope for producing a supporting, impermeable structure eme layer of rock building materials and is purged with the ash / water suspension _v For this 1 page drawing