NO160230B - PIPING SYSTEM, SPECIFICALLY A MULTI-CHANNEL PIPING SYSTEM, AND PROCEDURES FOR PREPARING THE PIPING SYSTEM - Google Patents

Abstract

The piping for liquid and/or gaseous fluids comprises an outer pipe (1) and at least one inner pipe (2) which surrounds a fluid pipe (3) maintained sliding particularly axially by means of slide blocks. The space between the inner pipe (2) and the fluid pipe (3) contains air. The inner pipe (2) is thermally insulated from the outer pipe (1) on its entire length by means of a synthetic elastic foam. The piping is essentially used for remote heating conduits, and for refrigerant conduits, of petrol and natural gas.

Description

The invention relates to a pipeline system, in particular a multi-channel pipeline system, for the transport of at least one liquid and/or gaseous medium, respectively suspensions, e.g. district heating line, refrigerant line, natural oil or natural gas line, with an outer pipe and with at least one inner pipe and possibly an additional inside » pipes arranged in the outer pipe, for example venting and ventilation pipes, where in the inner pipe there is a medium pipe made of metal or plastic which, while keeping an air gap between the inner pipe and the medium pipe, is displaceably stored in the axial direction by means of guide pieces, and where the cavity between the outer pipe and the inner tube or the inner tubes and possibly the additional tubes are foamed with elastic plastic foam, preferably polyurethane foam, so that the tube or tubes arranged in the outer tube are kept at a distance from each other and free of thermal bridges by means of this plastic foam body.

The invention also relates to a method for manufacturing this pipeline system, as stated in claim 16.

In the case of district heating lines, it is common to lay the insulated pipes through which the heating medium flows in jacket pipes to protect the former from external stresses. Such casing pipes can also be used for steam lines, refrigerant lines etc. in the chemical industry.

From AT-PS 295.093, a double-walled pipeline with an outer string of pipes is known in which an inner, insulated pipe string of metal, in particular steel pipes is slidably stored by means of spacers, each spacer consisting of at least three ribs which are preferably arranged parallel to each other distances around the circumference of the inner tube string and projecting from this in an approximate radial direction. In the case of this known pipeline, which is often used as a district heating pipeline, the outer pipe string consists of fibre-cement, preferably asbestos-cement pipe and each rib is likewise shaped from fibre-cement, for example asbestos cement, and attached separately to the inner

pipe string.

These known pipelines have so far mostly been

laid individually. In the case of district heating line systems with inlet and return, this results in considerable laying work, and the thermal insulation will also be unsatisfactory.

The purpose of the invention is to avoid these disadvantages and to provide a pipeline system that can be used particularly as a multi-channel pipeline system, so that the heat losses from district heating lines etc. can be reduced and the costs in connection with the laying of the pipe system can be reduced.

The present invention is characterized by the fact that the plastic foam body in the individual tube sections designed with an outer tube and at least one inner tube at the connection points protrudes axially beyond the ends of the outer tube and preferably also beyond the end or ends of the inner tube/tubes, so that the plastic foam bodies in adjacent tube sections have full end surface contact with each other.

The invention thus provides an optimally heat- or cold-insulated one-, two- or multi-conductor casing pipeline system, the space between the inner pipe (core pipe) and the outer (mantle) pipe being filled with a plastic foam. In a casing pipe, both supply lines and return lines can be routed for one or more temperature ranges,

which provides a very fast and rational laying method. This system also has the advantage that the damping of the insulation by day, ground, condensation, and in cases of damage occurs

end media water is prevented in an absolutely safe way by the installation of a separate drainage device. As a result, corrosion of the media pipes from the outside is no longer possible. The plastic foam also has a function as a distance holder and ensures that the pipes are kept at a correct distance in relation to each other.

According to the invention, the plastic foam body protrudes beyond the ends of the outer tube and preferably also beyond the ends of the inner tube or inner tube, for example 0.5-20 mm, so that the plastic foam bodies in adjacent tube lengths can lie against each other with full surface contact when the individual tube lengths are joined together. In this way, the occurrence of a heat or cold bridge in the connection point between the pipe lengths is prevented•

For the connection of the individual pipe lengths in the pipeline system, it is appropriate that in the case of continuous medium pipes in the connection points between adjacent outer pipes, the outer pipes are surrounded on the outside or inside by a sleeve that extends over the ends of the adjacent outer pipes, with the interposition of possibly pre-tensioned sealing rings .

If the medium pipes are also to be connected, it is appropriate at the connection point between adjacent medium pipes to ensure that the ends of the adjacent outer pipe and inner pipe are shifted in the axial direction in relation to this connection point, as a coaxial insulation body of essentially similar structure is inserted between the adjacent pipe lengths which have a tight fit, and that the outer pipes are surrounded on the outside by a sleeve or a sleeve that extends from the end of one pipe length, over the insulation body and to the end of the other pipe length.

It is also advantageous if the insulating body consists of two or more segments held together by means of at least one clamping element, the separation joints between the elements preferably extending in the axial plane.

It is advantageous if the axial end sides to. the foam material body and/or the insulation body is mainly designed planar, on which projections and/or recesses are preferably arranged on these end sides to achieve

of a job security.

Here, it is appropriate that the foam material body of the insulation body protrudes beyond the end sides of the insulation body, for example 0.5-20 mm, so that when the foam material body of the insulation body is joined, the foam material body will fit with full surface contact against the foam material body of the pipe device.

With regard to the storage of the medium pipe in the inner pipe, which storage can for example also be carried out as in AT-PS 295.093, according to the invention it is particularly proposed that the sliding pieces used for guiding the medium pipe in the inner pipe should be designed as sliding rails fixed on the outer circumference of the medium pipe, in particular by means of a tensioning element, for example a tensioning band, so that a force-respectively friction-stopping hold is achieved, as each sliding rail firstly has two support surfaces arranged in the axial direction at a distance from each other for pushing against the outer circumference of the medium pipe and secondly has at least one support surface for repulsion against the inner circumference of the inner tube.

These sliding rails are arranged on the circumference of the medium reed, as

two or more groups are arranged at an axial distance from each other. The number of sliding rails and their dimensions are determined accordingly

the present conditions.

According to the invention, the sliding rails can consist of an axially extending, preferably U-, V- or W-shaped inclined band with legs protruding from the ends which form the support surfaces of the sliding rails against the medium pipe. Such sliding rails can be produced in a simple way by bending a band.

Here, it is appropriate that the clamping elements rest on the outside against the legs that form the support rafts against the medium pipe, and that they are connected to these, for example by spot welding. ■ The clamping element thereby encloses the slide rails arranged in a radial plane on the outside and thus ensures the rails' friction-locking connection with the medium pipe.

To improve the guidance, it is advantageous that the slide rail

has a preferably centrally arranged, particularly in an axial plane running step which on its side facing the inner tube is connected to the sliding rail and essentially extends into the area of the outer circumference of the medium tube.

An additional position lock is achieved if the step on its side facing the medium pipe is provided with grooves, incisions or the like.

It is advantageous to leave the support surfaces of the sliding rail mainly flat.

However, it is also possible to lay the slide rail radially

let the outer support surface, which serves to push the sliding rail against the inner circumference of the inner tube, be convexly curved.

Here, it is appropriate that the radius of curvature of the support surface is smaller than the radius of curvature of the inner tube's inner circumference.

The method according to the invention for manufacturing the pipeline system consists in pushing at least one inner pipe, preferably also made of fiber or asbestos cement, into an outer pipe, preferably made of fiber or asbestos cement, after which the cavity between the outer pipe and inner pipe is foamed with elastic foam f ,, in particular polyurethane foam, in that the foam body in the axial direction protrudes over the ends of the outer tube, for example 0.5-20 mm, after which the individual tube lengths formed in this way are joined together, in that the axial end surfaces of the foam bodies are pressed against each other in the axial direction and the internal or externally, a sleeve or a sleeve is pushed over the connection point of the outer pipes, and that the medium pipe in-

is guided in the inner tube and stored using sliding pieces.

When carrying out this method, at the connection points of the medium pipes, their ends can first be connected to each other, e.g. by welding, soldering, gluing or the like, after which an insulating body is placed over this connection point which has a foam material body protruding in the axial direction beyond the end sides, for example with a protrusion of 0.5-20 mm, after which the individual pipe lengths under interconnection of this insulating body are pressed against each other in the axial direction and over the insulation body, a sleeve or sleeve is pushed which extends over the ends of the adjacent outer pipes.

The invention shall be explained in more detail with reference to the drawings, where exemplary embodiments of the invention are shown.

The drawings show:

Fig. 1 a cross-section through one pipe arrangement according to op invention, with only one medium pipe (one-conductor), Fig. 2 shows a cross-section through the pipe arrangement according to

the invention, with two medium pipes (two-conductor),

Fig. 3 shows a cross-section through a pipe device according to

the invention, with three medium pipes (three-conductor),

Fig. 4 shows a cross-section through a pipe device according to

the invention, with four medium pipes (four-conductor),

Fig. 5 shows a cross-section through a pipe arrangement according to the invention, with several medium pipes and additional ventilation and drainage pipes (multi-conductor),

Fig. 6 shows a section along the line VI-VI in fig. 5,

Fig. 7 shows a longitudinal section through the pipe arrangement in the area at the connection point between the casing pipes (short connection), Fig. 8 shows a longitudinal section through a pipe arrangement in the area of the connection point between the casing pipe and medium pipe (long connection), Fig. 9 shows a section through a vertical branch shaft,

Fig. 10 shows a section along the line X-X in fig. 9,

Fig. 11 shows a longitudinal section through the inner, double-walled pipeline consisting of casing pipe and medium pipe,

Fig. 12 shows a section along the line XI1-XII in fig. 11,

Fig. 13 shows detail A from fig. 11 on a larger scale, Fig. 14 shows an enlarged image of the sliding rail, in section,

Fig. 15 shows a floor plan of fig. 14, and

Fig. 16-20 show different embodiments of the sliding rails, all in section.

In the pipeline system according to fig. 1, an inner pipe or a core pipe 2 of fiber cement or asbestos cement is arranged in an outer pipe or a casing pipe 1 of fiber cement or asbestos cement. In the core tube 2, a medium tube 3 consisting of metal is stored displaceably in the axial direction by means of slide rails 4. The inner tube 2 is arranged without thermal bridges in the outer tube 1 over its entire length, the annular cavity between the outer tube 1 and the inner tube 2 being essentially completely foamed with a elastic plastic foam 5. In addition, a ventilation pipe 6 and a drainage pipe 7 are inserted into the foam body.

The inner tube is held correctly in the outer tube by means of

of the foam body, which preferably consists of elastic hard polyurethane foam.

The annular gap between the inner tube and the medium tube is not filled with foam material, but is designed as an air gap 8.

In the case of the pipeline system in fig. 2, two spaced inner tubes or core tubes 2 are arranged in an outer tube or casing tube 1 made of fiber cement or asbestos cement

of fiber cement or asbestos cement. In the inner tubes, a respective medium tube 3 consisting of metal is arranged

which is stored displaceably in the axial direction by means of

sliding rails 4. The inner tubes 2 are arranged without thermal bridges 1 the outer tube 1 over its entire length, as the annular cavity between the outer tube 1 and the inner tubes 2 is essentially completely foamed with elastic plastic foam 5. In the foam body, a venting tube 6 and a drainage tube are also inserted here as well 7.

In the pipeline system according to fig. 3, in an outer pipe or casing pipe 1 of fiber or asbestos cement, three spaced inner tubes or core pipes 2 of fiber or asbestos cement are arranged. In the inner tubes, a medium tube 3 consisting of metal is arranged, which is stored displaceably in the axial direction by means of slide rails 4. The inner tubes 2 are thermally bridge-free arranged in the outer jacket 1 and in relation to each other over the entire length, the annular cavity between the outer tube 1 and the inner tubes 2 in the main body are completely foamed with elastic artificial foam 5. A drainage tube 7 is also inserted in the foam body.

As shown, the cross-sections of the inner tubes are of different sizes, i.e.

that an inner tube has a smaller cross-section than the other two.

In the case of the pipeline system in fig. 4, in an outer pipe or casing pipe 1 made of fiber or asbestos cement, four spaced apart inner pipes or core pipes 2 of fiber cement or asbestos cement are arranged. In the inner tubes, a respective medium tube 3 consisting of metal is arranged, which is stored displaceably in the axial direction by means of sliding rails 4. The inner tubes 2 are arranged without thermal bridges in the outer tube 1 and also in relation to each other over the entire length, the annular cavity between the outer tube 1 and the inner tubes 2 are essentially completely foamed with elastic plastic foam 5. In addition, venting pipes 6, drainage pipes 7 and auxiliary pipes 9 are inserted into the foam body.

In fig. 5 and 6, a pipeline system is shown where the

four inner tubes 2 are arranged in an outer tube 1. These are spaced apart and are arranged without thermal bridges. Each inner tube contains a medium tube 3 which is supported axially displaceably by means of sliding rails 4. In addition, a ventilation tube 6, drainage tube 7 and signal conductor auxiliary tube 9 are arranged in the outer tube 1. The cavity between the outer tube 1

and the inner tubes 2 are, as in the previous embodiments, foamed with hard polyurethane foam 5. Channels 10 are formed in the foam body 5, a depth of approx.

5-10 mm from the foam surface, which channels lead from the inner pipes 2 and to the drainage pipes 7.

As particularly shown in fig. 6 the foam body protrudes 5 approx.

5-10 mm beyond the ends of the outer tube 1 and the inner tubes 2 respectively in the axial direction. The overmeasure, i.e. the protruding stretch of the foam body 5 at the mentioned ends, is in fig. 6 denoted by a.

Fig. 7 shows the connection between the outer pipes 1 in one of the pipeline systems described above. This is a short connection, where a medium pipe joint is not necessary. The drawing shows a one-conductor system according to fig. 1, but can in principle also be used for the two- and multi-conductor systems according to fig. 2-6.

In the left half of fig. 7 shows a sleeve connection which encloses the outer pipes 1 in the area at the adjacent ends. For example, two to four sealing rings 12 can be placed in the sleeve 11.

In the right half of fig. 7 shows a sleeve connection with two to four sealing rings 12 which are surrounded by a sleeve 13 and which are clamped over the ends of the outer tubes 1.

In both cases, the end surfaces of the foam bodies are pressed

5 in adjacent pipe lengths against each other with flat installations.

Fig. 8 shows the connection between the outer pipes 1 in one of the pipe devices described above. This is a long connection, where the medium pipes are also joined. As in fig. 7, the drawing shows a one-conductor system according to fig. 1, but the design can also be used for the two- and multi-conductor systems according to fig. 2-6.

The long connection includes a sleeve 11 or a sleeve 13 as in fig. 7, but the sleeve/sleeve is significantly longer than in fig. 7. Between the adjacent outer pipes 1, an insulation body 14 is arranged, the structure of which is identical to the pipe arrangement, and thus also has a foam material body 5'.

In accordance with the number of inner tubes or medium tubes 2 and 3 respectively, the insulation body is divided into a number of segments. These segments are held together by means of tension bands 15. The sleeve II and sleeve 13 thus extend in the axial direction from the end of one outer tube and over the insulating body 14 in the direction towards the end of the other outer tube. The end surfaces of the foam bodies 5 and 5' projecting beyond the ends of the outer tubes 1 and the insulation body 14 respectively are in the same way as in fig. 7 pressed firmly against each other. The connection point 3' for the medium pipes 3 is displaced in the axial direction in relation to the axial end surfaces of the foam bodies 5 and the ends of the outer pipes 1 and the inner pipes 2, and lies inside the insulation body 14. The connection between adjacent medium pipe ends takes place in a known manner by welding, soldering, gluing, etc.

The foam body 5' consists of an elastic synthetic foam, preferably of the same material as in the foam body 5, for example hard polyurethane foam.

Fig. 9 and 10 show a vertical branch shaft for a pipeline system according to the invention. This shaft is insulated accordingly. The shaft denoted by 16 includes a shaft body 17 with a shaft roof 18 and an entry dome 19 which can be closed with an insulated lid 20 in a cross-surface waterproof and heat-insulating manner. The entire shaft is provided with an inner lining 21 of hard polyurethane foam, and is internally covered with a heat-reflective layer 22. Branch connections and shaft connections 23 are insulated in the same way as the pipe string itself.

In the case of the pipeline system in fig. 11 and 12, an inner pipe or core pipe of fiber cement or of asbestos cement is arranged in an outer pipe or casing pipe 1 of fiber cement or asbestos cement. In the inner tube, a medium tube 3 consisting of metal is stored displaceably in the axial direction by means of sliding rails 114. The inner tube 2 is arranged without thermal bridges in the outer tube 1 over its entire length, the annular cavity between the outer tube 1 and the inner tube 2 being essentially completely foamed with an elastic synthetic foam 5. In addition, a ventilation pipe 6 and a drainage pipe 7 are inserted into the foam body.

In fig. 13-20, the sliding rail 114 is shown in more detail. The sliding rail 114 has the form of a bridge-shaped several times inclined or angled band which has two support surfaces 118,119 lying in the axial direction at a distance from each other for abutment against the outer circumference of the medium pipe 3 and a support surface 110 for abutment against the inner circumference of the inner tube 2. Several such sliding rails 114 are arranged at a distance from each other over the circumference of the medium pipe 3, in one and the same radial plane, and are held force-locking or friction-locking firmly against the circumference of the medium pipe by means of two clamping bands 111. The clamping bands 111 can be connected to the sliding rails 114 , for example by means of spot welding. Depending on its length, two or more such groups of slide rails arranged in a radial plane can be used to support a medium pipe 3.

As particularly shown in fig. 14 and 15, the sliding rail 114 is provided with a central step 112 which extends in an axial plane across the annular gap between the inner tube 2 and the medium tube 3. On its side facing the inner tube 2, the step is firmly connected to the sliding rail 114. On the side facing the medium tube

3 facing side, the step 112 is provided with grooves 113, in-

cut or similar.

In the embodiment shown, the support rafts 118,119,110 are planar. However, the support rafts can also be curved. In particular, the radially outer support surface 110, which

serves to push the sliding rail 114 against the inner circumference of the inner tube 2, have a convex curvature. It is then appropriate that the radius of curvature of the support surface is smaller than the radius of curvature of the inner tube's inner circumference.

In the design example in fig. 16 is the one for axial guidance

of the medium tube 3 in the inner tube 2 used sliding rail 14 formed by a mainly U-shaped inclined band. The underside of the U forms the support surface 110 for abutment against the inner circumference of the inner tube 2, while the support rafts 118,119 for abutment against the outer circumference of the medium tube 3 are formed by legs protruding from the upper ends of the U. The tension bands 111 are located

against these legs and holds the sliding rail 114 firmly on the medium pipe 3. The step 112 is designed as in fig. 14 and 15.

Fig. 17 shows a sliding rail 114 which consists of an approximately trapezoidal inclined band with protruding legs and a step 112. The step 112 does not necessarily have to be arranged centrally, but can also be arranged on one side or at both outer axial ends. Fig. 18 shows a sliding rail 114 which consists of an approximately triangular or V-shaped bent band with protruding legs for the tension bands 111. With this design, for example, no step is necessary. Fig. 19 and 20 show sliding rails 114 in the form of double arches or double rails, the tension band 111 resting against a centrally arranged step 113.

The sliding rails can be made of metal, especially steel, and can optionally be surface-treated ... or provided with a coating so that a corresponding corrosion protection is provided as well as a friction reduction.

The invention can be used for pipe strings with arbitrary cross-sections, i.e. also non-round or angular cross-sections, for example oval, elliptical or polygonal cross-sections, respectively the cross-section of a Releaux triangle.

In addition to fiber cement or asbestos cement, concrete, synthetic resin concrete, stoneware, plastics, metal etc. can also be used as material for outer and inner pipes.

When the invention is used for district heating systems, the pipe device can be particularly used for the transport of "cold district heating", geothermal water, hot water systems up to 90°, the hot water system up to 130°, and hot water systems up to 170°C.

When transporting "cold district heating", a relevant area of application is the transport of cooling water with a very low temperature level from power plants and industries. In the one-pipe system, the medium is transported to the consumers and brought up to the required heating temperature with the help of heat pumps. The water cooled by the heat pumps is removed locally in

a recipient. Such systems are very economical, as they can be laid in the cheapest way, in the same way as a water main. Investigations have shown that even without insulation, relatively "hot water" with approx. 15-20°C is transported economically over several kilometres, but for ecological reasons insulation is still provided.

When transporting geothermal water, pipes made of asbestos cement are used in particular, which are provided with thermal insulation in accordance with the current requirements. The corrosion occurring in steel pipe systems as a result of drainage water can be ruled out by using pipes made of asbestos cement, which is a non-metallic material. Of course, it must be ensured that only insulation materials are used that retain their effect even when exposed to moisture, i.e. no fiber insulation materials, for example.

The systems described above involve open circuits (one-pipe system), i.e. that the medium water after the heat withdrawal at the consumer (for example heat pump or converter) is led to the nearest recipient.

In hot water systems up to 90°C, a heat transport system is used consisting of asbestos cement pressure pipes as medium pipes for supply and return, a common casing pipe made of asbestos cement and a foaming of the cavity between the medium and casing

pipes using polyurethane foam. The connection between the pipes (medium and casing pipes) is made with the help of ordinary asbestos-cement connections fitted with hot water-resistant seals. As a result of the pipes' expansion possibilities in each connection

additional expansion compensators and fixed points can be completely dispensed with. Compared to conventional systems, large savings are therefore made possible during construction and installation.

For hot water systems up to 90°C, a closed circuit (two-pipe system) is used, where the return water is returned to the boiler system for renewed heating. Depending on the chemical composition of the conducting water and the water temperature, the asbestos cement pipes for the medium pipes can also be provided with a coating.

For hot water systems up to 13 0°C as well as hot water systems up to 170°C, the pipe structure is the same. One or more core tubes of asbestos cement are built into an asbestos-cement casing pipe, into which steel medium pipes are inserted, kept at a distance by means of sliding rails against the core pipe. This can happen either at the manufacturing site or at the construction site. The space between the casing pipe and the core pipe is foamed with polyurethane, the insulation thickness being chosen in accordance with the relevant temperature ranges - 130°C

and 170°C.

The systems are dimensioned so that a jointing of the asbestos-cement casing pipes only takes place in the area of the steel pipe welding seams, using insulated long connections (up to steel DN 200 every 11 m and beyond every 16 m).

The intermediate casing pipes are connected to each other by means of short connections.

This connection device has the advantage that each of the welding seams carried out on the construction site is located in the area of a long connection, so that the testing of these welding seams can take place without delay for the further laying.

These systems also offer the possibility of pulling in steel pipe strings up to a length of 300 m in a single work pass in the already laid casing pipe and the core pipes arranged therein.

Furthermore, it is also possible to replace longer stretches of steel pipe, as with correspondingly large core pipes later capacity expansions can also be carried out by inserting larger steel pipes (larger light opening) without it being necessary to dig up or dismantle the entire system.

The systems described above can be used in urban district heating networks and for large transport lines over land. In the latter case, the laying can take place underground as well as above ground.

In order to achieve uniform insulation over the entire district heating system, starting at the heat generator and ending at the heat consumer, all parts that belong to a complete system are also insulated. This ensures that there are no weak points in the entire system with regard to the quality of the insulation. Investigations have shown that in some cases the heat losses through shafts, fixed points, compensators and other building components can amount to several times the heat loss of the pipeline itself. In addition, often defective construction will cause a significant reduction in the function of the insulation and thus cause an increase in operating costs.

In order to avoid such weak points, pre-insulated pipelines, pre-insulated connections, pre-insulated fixed points and pre-insulated shaft components are used.

In that all these components are completed ex works

it was ensured that the heat loss on which the planning is based is not exceeded either. Unpleasant surprises in the form of uncalculated heat losses, which otherwise only become apparent after the district heating network has been put into use, can thus be ruled out with certainty.

To further enhance the advantage achieved with prefabrication, a building component system is also used for the installation technical devices, which system includes, for example, prefabricated branch shafts, prefabricated pump shafts, prefabricated compensator shafts and prefabricated delivery stations.

When carrying out these plant parts, the individual wishes of the district heating operator can also be taken into account, while at the same time standardization can be achieved in technical and economic terms. These construction parts can also be delivered already installed on the construction site if desired.

As a result of the largely complete prefabrication, it is not only possible to offer technically and economically optimal products, but it is also possible to achieve that district heating networks in the future can be built in a shorter time and thus cheaper. The essential criteria for the systems are: use of multi-conductor casing pipes according to the invention, which pipes have significantly smaller outer diameters than in traditional systems, and the complete program of prefabricated system components.

With the invention, compared to the district heating systems used today, large savings can be achieved, both with regard to construction costs as well as with regard to - which is even more decisive - operating costs, as a result of less heat loss.

Example 1

The example concerns a district heating supply of a small town, where, as a result of the low supply temperature of 90°C

a hot water system with 90°C was used.

The problem was to supply 320 consumers with a total of approx. 7.5 MW total power. An additional requirement was also that the system should be designed so that it could easily be expanded to a larger network despite the low initial connection density.

The following values for the facility were specified:

As can be seen from the table, per running meters of district heating route with cable dimensions from DN 20 - DN 250, savings of approx. 50% compared to pre-insulated steel pipes. A comparison with culvert canal systems was not relevant, as the bottom conditions and topography ruled out such a system in advance.

Example 2

The example concerns the most economical solution for the installation of a district heating transport line with the following technical values:

There was a requirement for a system which, with the same regulation cross-section, enabled laying both above and below ground. Due to the high transport effect, it was proposed to split the cable cross-section into two inlets and return runs. This not only provided the optimal solution for the lay cross-section, but also resulted in the advantage that, in sum, there were lower installation costs for the required 4 x steel diameter 450, than with 2 x steel diameter 650.

The heat losses for this multi-conductor system according to the invention, with hot water of 130°C and 170°C respectively, over a total length of 17,500 m approx. 1 K with a maximum temperature drop.

This very low heat loss could be achieved as a result of the use of the multi-conductor system and by a consistent elimination of all weak points (burners, fixed points, shafts)

as a result of the use of prefabricated and pre-insulated building parts.

The construction costs for this system (incl. earthworks)

is significantly lower than for known systems, since factory-produced prefabricated building parts were also used for this system for all components. All fixed points, compensator shafts and branch shafts have a heat-insulating design.

In comparison, a design such as a culvert channel, with significantly higher total costs, will give a calculated significantly higher temperature loss of approx. 7 K on it approx. 17,500 m long route.

Claims (17)

1. Pipeline system, in particular a multi-channel pipeline system, for the transport of at least one liquid and/or gaseous medium, respectively suspensions, for example district heating line, coolant line, natural oil or natural gas line, with an outer pipe (1) and with at least one inner pipe (2) and possibly additional pipes arranged inside the outer pipe (1), for example venting and ventilation pipes (6,7,8), where in the inner pipe (2) there is a medium pipe (3) made of metal or plastic which, while keeping an air gap between the inner pipe (2) and the medium pipe (3) are displaceably stored in the axial direction by means of guide pieces (4), and where the cavity between the outer pipe (1) and the inner pipe (2) respectively the inner pipes (2) and possibly the additional pipes (6,7 ,8) is foamed with elastic plastic foam, preferably polyurethane foam, so that the pipe or pipes (2,6,7,8) arranged in the outer pipe (1) are kept at a distance from each other and free of thermal bridges by means of this plastic foam body (5), characterized by that plastic foam the egg (5) in the individual tube sections formed with an outer tube (1) and at least one inner tube (2) at the connection points protrudes axially beyond the ends of the outer tube (1) and preferably also beyond the end or ends of the inner tube/tubes (2 ), so that the plastic foam bodies (5) 1 adjacent pipe sections have full end surface contact with each other. 2. Pipeline system according to claim 1, characterized in that the aforementioned guide pieces (4) are designed as force/friction-locking fixed slide rails (114), on the outer circumference of the medium pipe (3), held by means of a clamping element (111), each slide rail (114 ) has two support surfaces (118,119) arranged in the axial direction at a distance from each other for abutment against the outer circumference of the medium pipe (3) and at least one support surface for abutment against the inner circumference of the inner tube (2). 3. Piping system according to claim 1 or 2, characterized in that in the case of continuous medium pipes (3), a sleeve or sleeve (11, 13) surrounding the outer tubes on the outside or inside is arranged at the connection point between adjacent outer pipes (1), which sleeve/sleeve under interconnection of possibly biased sealing rings (12), extend over the ends of the adjacent outer tubes (1) (fig. 7.) 4. Pipeline system according to claim 1 or 2, characterized in that at the connection point between adjacent medium pipes (3) the ends of the adjacent outer pipes (1) and inner pipes (2) are displaced in the axial direction in relation to this connection point, as there is between the adjacent pipe sections a coaxial insulation body (14) constructed in the same way is inserted, which has a tight fit, while the outer pipes (1) are surrounded on the outside by a sleeve or sleeve (11,13) which extends from the end of one pipe section, over the insulation body (14) and to the end of the second pipe section (fig. 8). 5. Piping system according to claim 4, characterized in that the insulating body (14) consists of two or more segments held together by means of at least one clamping element (15), the separation joints between the elements preferably being in an axial plane. 6. Piping system according to one of the claims 1-5, characterized in that the axial end sides of the foam material body (5) and/or the insulation body (14) are designed in a manner known per se to be essentially flat, with protrusions and/or or recesses for job security. 7. Piping system according to one of claims 4-6, characterized in that the foam material body (5<1>) in the insulation body (14) protrudes beyond its ends, so that upon assembly, the foam material body (5<1>) in the insulation body (14) will have full end surface system against the foam body (5) in the pipe device (fig. 8) . 8. Piping system according to one of claims 1-7, characterized in that at least one channel (10) running in a radial plane is formed in the foam body (5), which channel runs from the circumference to an inner tube (2) and to a venting/ ventilation pipe (6,7) (fig. 5). 9. Pipeline system according to claim 2, characterized in that the slide rails (114) consist of a preferably U-, V- or W-shaped inclined band running in an axial plane with legs protruding from the ends which form the support rafts (118, 119) for the slide rails (114) towards the medium pipe (3) (fig. 14,16, 17,18) . 10. Pipeline system according to claim 9, characterized in that the clamping elements (111) rest against the outside of the legs that form the support rafts (118,119) against the medium pipe (3), and are possibly connected to these. 11. Piping system according to claim 9 or 10, characterized in that the slide rail (114) has at least one, preferably centrally or laterally arranged step (112) running in an axial plane, which is connected to the slide rail (114) on its side facing the inner pipe (2) and mainly extends to the area of the outer circumference of the medium pipe (3) (fig. 4). 12. Piping system according to claim 11, characterized in that the step (112) on its side facing the medium pipe (3) is provided with grooves, incisions or the like (113) (fig. 14). 13. Pipeline system according to one of the claims 9-12, characterized in that the support rafts (118,119) on the sliding rail (114) are essentially flat (fig. 14-20). 14. Pipeline system according to one of claims 9-13, characterized in that the radially outer support surfaces (110) on the sliding rail (114), which support surfaces serve to support the sliding rail (114) against the inner circumference of the inner pipe (2), have convex curvature. 15. Piping system according to claim 14, characterized in that the radius of curvature of the support surface (110) is smaller than the radius of curvature of the inner circumference of the inner pipe (2). 16. Method for manufacturing the pipeline system according to one of claims 1-15, characterized in that at least one inner pipe, preferably also made of fiber or asbestos cement, is inserted into an outer pipe, preferably made of fiber or asbestos cement, after which the cavity between the outer pipe and inner pipe is foamed with elastic foam material, particularly polyurethane foam material, in that the foam material body in the axial direction is made to protrude above the ends of the outer tube, after which the individual tube sections formed in this way are joined together, during which the axial end surfaces of the foam body bodies are pressed against each other in the axial direction and a sleeve is pushed over the connection point between the outer tubes or sleeve, and the medium pipe is introduced into the inner pipe and stored using sliding pieces. 17. Method according to claim 16, characterized in that at the connection points between the medium pipes, their ends are first connected to each other, after which an insulating body is placed over these connection points, which has a foam material body protruding in the axial direction from the end sides, after which the individual pipe sections are pressed against this insulating body during interconnection each other in the axial direction and a sleeve or sleeve is pushed over the insulating body which extends over the ends of the adjacent outer pipes.