DE102012111140A1 - Use of a first and a second polymer material - Google Patents

Abstract

The present invention relates to the use of a first polymer material which is an uncrosslinked polyolefin and has an internal pressure resistance at or above a reference curve in the temperature range of 10 to 110 ° C, which corresponds to the following definition: lg t = -219 - (62600,752 × lg sigma) / T + 90635,353 / T + 126,387 × lg sigmawobei t is the time in h, T is the temperature in K and sigma is the hydrostatic stress in MPa, for the production at least a layer (1.1) of a multilayer pipe (1) or at least one layer (1.1) of a multilayer pipe molding (1 ') and a second polymer material which is an uncrosslinked polyolefin and has an MRS value (minimum required strength) of> 10 MPa and has an FNCT value according to ISO 16770 at 80 ° C and sigma 4 N / mm 2 at 1% Arkopal of> 10,000 h, for the production of at least one further layer (1.2) of a multilayer R ear (1) or at least one further layer (1.2) of a multilayer pipe molding (1 ') for a pipe arrangement of a geothermal heat recovery or storage device.

Description

The invention relates to the use of a first and a second polymer material for producing layers of a multilayer pipe or layers of a multilayer pipe molding for a geothermal heat recovery or storage device, further comprising the multilayer pipe or multilayer pipe molding and a pipe assembly having at least one multilayer pipe or at least one multilayer pipe molding, and finally a geothermal heat recovery or storage device with such a pipe assembly.

Supplying homes and buildings with thermal energy for heating purposes, which is increasingly being carried out with the help of renewable energies, for example using geothermal energy, is a cheap and efficient technology. In addition, cooling technology is also establishing itself, whereby heat is extracted from the building and introduced into the ground.

For this geothermal heat recovery or storage devices are used, which are able to exchange heat energy with the ground by the flowing in the pipe assemblies fluid extracts heat energy from the ground or feeds this.

For the fluid-carrying pipe are known from the prior art, such as crosslinked polyethylene (PE-X) or steel.

Such known from the prior art tubes are expensive to produce. The piping arrangements for geothermal heat recovery or storage devices are generally sunk into boreholes in the ground. This can lead to damage to the outer surface caused by sharp objects in the borehole.

Straight pipes made of polyethylene are prone to slow crack growth in the event of damage when exposed to point loads, whereupon the pipe can fail due to breakage or leakage. The continuous service temperature - about the size of 40 ° C - is limited in the material polyethylene due to the relatively low heat resistance.

This is the object of the invention, which has as its object to select a suitable combination of polymer materials, which meets the high demands placed on geothermal pipe arrangements, and for the production of a pipe or a pipe fitting for a pipe arrangement of a geothermal energy production. or storage device. In addition, the combination of polymer materials should ensure that the pipe or pipe fitting is extremely resistant to damage and possible slow crack growth, as well as higher service temperatures, such as occur in cooling operation in a geothermal probe, withstand.

The object is achieved according to the invention and overcome the known from the prior art disadvantages in that a first polymer material is used which is an uncrosslinked polyolefin and in an internal pressure test according to ISO 9080 has an internal compressive strength which is on or above a reference curve in the temperature range from 10 to 110 ° C, which corresponds to the following definition: lg t = -219 - (62600.752 × lg sigma) / T + 90635.353 / T + 126.387 × lg sigma where t is the time in hours (h), T is the temperature in Kelvin (K) and sigma is the hydrostatic stress in megapascals (MPa) to produce at least one layer of a multilayer pipe or at least one layer of a multilayer pipe molding, and a second polymer material which is an uncrosslinked polyolefin and has a minimum required strength (MRS) of> 10 MPa and a FNCT value ISO 16770 at 80 ° C and sigma 4 N / mm ² at 1% Arkopal of> 10,000 h, for producing at least one further layer of a multilayer pipe or at least one further layer of a multilayer pipe molding for a pipe arrangement of a geothermal heat recovery or storage device.

The over internal pressure tests after ISO 1167-1 and ISO 1167-2 The lower confidence limits of the predicted internal compressive strength (sigma LPL values) determined for this material must at least correspond to the corresponding values of the abovementioned reference characteristic, ie lie on or above the reference curve.

By using the combination of polymer materials according to the invention as described above, it is possible to provide a multilayer pipe or a multi-layer pipe molding each having at least one layer and another layer of said polymer materials for a pipe assembly of a geothermal heat recovery or storage device.

Such a tube or tubular molding can be produced in a simple manner, causes low production costs, is durable, withstands the prevailing pressures and temperatures of the medium conveyed in them over long periods of time, and can be connected to one another by welding techniques in a simple manner.

In particular, such a pipe or pipe fitting resists the conditions under which a geothermal heat recovery or storage device is operated. These include the permanent action of the fluid under temperature and pressure on the wall of polymer material, pressure peaks and fluctuations as well as temperature peaks and fluctuations. Likewise, the expansion behavior of the material must be taken into account, which is decisively influenced by temperature and pressure. Finally, a durable material is needed since a geothermal heat recovery or storage device should have a long life.

And finally, the tube or pipe fitting does not tend to crack when damaged, causing no failure. The duration of use temperature is advantageously increased in the inventive combination of polymer materials.

All this is ensured by the use of the polymer materials described above.

It has been found in the context of the present invention to be advantageous if the polymer material is a polyethylene.

A polyethylene is a very easily processable polymer material, which can be processed both by extrusion and by injection molding in order to produce tubes or pipe parts.

A polyethylene is inert, durable, and is not attacked by the conductive fluids when used in a geothermal heat recovery or storage device, moreover, it is conveniently available.

It has proved to be very advantageous in the context of the invention if the innermost, i. the layer of the first polymer material facing the lumen of the tube or tubular shaped part, as described above, is formed.

This innermost layer of the tube or tubular part delimits the lumen on its surface comes into contact with the medium to be conductive.

If the innermost layer, ie the layer facing the lumen of the tube or pipe part, is formed from the first polymer material, which is an uncrosslinked polyolefin, and in an internal pressure test according to FIG ISO 9080 has an internal compressive strength which is on or above a reference curve in the temperature range from 10 to 110 ° C, which corresponds to the following definition: lg t = -219 - (62600.752 × lg sigma) / T + 90635.353 / T + 126.387 × lg sigma where t stands for the time in hours (h), T for the temperature in Kelvin (K) and sigma for the hydrostatic stress in megapascals (MPa), this is particularly resistant to slow crack growth.

In an alternative embodiment of the present invention, it has proven to be advantageous if the second polymer material forms the lumen-limiting layer of the multilayer pipe or the multilayer pipe molding.

When the innermost layer, ie the layer facing the lumen of the pipe or pipe molding, is formed of the second polymer material which is an uncrosslinked polyolefin and has a minimum required strength (MRS) of> 10 MPa and a FNCT value ISO 16770 at 80 ° C and sigma 4 N / mm ² at 1% Arkopal of> 10,000 hours, this is particularly suitable for elevated temperature applications such as those encountered in cooling operation on a geothermal probe tube assembly.

It has proved to be very advantageous in the present invention if an additional layer is arranged between the layer of the multilayer pipe or of the multilayer pipe molding and the further layer of the multilayer pipe or the multilayer pipe molding.

It is particularly favorable if the additional layer is a primer layer or a diffusion barrier layer or a protective layer or a reinforcing layer or a leveling layer or a heat conducting layer.

It has proved to be extremely advantageous to provide a primer layer which improves or enables the adhesion of the layers of the first and the second polymeric material. An adhesive layer causes a particularly strong bond between two adjacent layers, so that an adhesive bond is formed. Such a primer layer may be composed of a polymeric material containing polyethylene or polyethylene copolymers. It is also included in the invention that adhesion promoter layers are formed between all adjoining layers.

A diffusion barrier layer to be provided according to the present invention prevents or reduces to a very high degree the passage of substances from the environment into the lumen of the tube or out of the lumen of the tube into the environment. It has proved to be particularly favorable when as Diffusion barrier layer is a barrier layer is used, which prevents the passage of water vapor or / and the passage of oxygen. In the context of the invention can also be provided that a plurality of diffusion barrier layers are provided in a combination. Such a diffusion barrier layer may be disposed at any position in the wall of the multilayer pipe or multilayer pipe molding according to the invention, but finds a preferred location between the layer and the further layer or as the outermost layer or as the second outermost layer of the wall.

In a preferred embodiment of the present invention, it has proven to be advantageous if an outer layer which forms the outermost layer of the pipe or pipe molding is arranged. This outer layer acts as a protective layer.

By providing a protective layer which forms the outermost layer of the pipe or pipe molding, a highly resistant pipe or pipe molding can be made, which ensures a high resistance to damage during storage, transportation and installation of the pipes or pipe fittings. In the context of a favorable development of the invention it can be provided that the protective layer is made of a polyethylene (PE) or a polyethylene with increased resistance to stress cracking or a cross-linked polyethylene (PE-X) or similar resistant materials.

A reinforcing layer to be provided in accordance with the present invention may be formed as a braid which enhances the pressure resistance of the multilayer pipe or the multilayer pipe molding of the present invention. Such a braid may be made by means of fibers, tapes, threads or filaments of polymeric material and / or metal. Such a reinforcing layer may be disposed at any position in the wall of the multi-layered pipe or the multi-layered pipe formed part according to the invention, but finds a preferred location between the layer and the further layer or as the second outermost layer.

In the context of the invention has further been found to be advantageous when a heat conducting layer is arranged. Such a heat-conducting layer may contain, for example, particles which conduct the heat particularly well. These may be particles of inorganic or metallic type. Likewise, the heat conducting layer can be designed in multiple layers. These are also multi-layered, possibly containing different particles can be produced. As the material of the heat conducting layer, it is preferable to select one which exhibits no failure, degradation or the like from the temperature of the medium to be conducted. The thickness of the heat-conducting layer is chosen so that the desired heat-conducting effect occurs. Such a heat conducting layer can be arranged at any point in the wall of the multilayer pipe or multilayer pipe molding according to the invention, but finds a preferred location as the outermost or second outermost layer.

In a preferred embodiment of the present invention, it has proven to be advantageous if a compensation layer is arranged. Such a compensation layer can advantageously compensate, for example, for different thermal expansions of layers and reduce possible stresses in the multilayer pipe or the multilayer pipe part. Such a leveling layer may be disposed at any location in the wall of the multilayer pipe or multilayer pipe molding of the invention, but finds a preferred location between the layer and the further layer.

The invention also encompasses the use of a first and a second polymer material for producing layers of a pipe or pipe molding, wherein at least one of the layers is modified. The modification of at least one of the layers is based on tailoring the desired properties of the polymeric material of the respective layer. This can affect both the properties in use, as well as the properties in the production. Thus, for example, the polymer material can be optimized in terms of its stabilization against thermal degradation by a corresponding modification - which can affect both the polymer material itself, as well as the addition of appropriate additives. In the manufacture of the tubes or pipe fittings, by providing suitable auxiliaries, care can be taken that the molding proceeds in a gentle manner without excessive thermal stress by adding appropriate additives, such as lubricants or release agents, to the polymeric material.

The method for producing a multilayer pipe or multilayer pipe molding is as follows:
The method for producing a multilayer pipe or multilayer molding for a pipe assembly according to the present invention is based on a layer of the multilayer pipe or the multilayer molding of a first polymer material which is a non-crosslinked polyolefin and in an internal pressure test according to ISO 9080 has an internal pressure resistance which is on or above a reference curve in the temperature range from 10 to 110 ° C, which corresponds to the following definition: lg t = -219 - (62600.752 × lg sigma) / T + 90635.353 / T + 126.387 × lg sigma where t is the time in hours (h), T is the temperature in Kelvin (K) and sigma is the hydrostatic stress in megapascals (MPa), and a second polymer material which is an uncrosslinked polyolefin and has an MRS value (minimum required strength) of> 10 MPa and a FNCT value after ISO 16770 at 80 ° C and sigma 4 N / mm ² at 1% Arkopal of> 10,000 h, for forming at least one further layer of a multilayer pipe or at least one further layer of a multilayer pipe molding for a pipe assembly of a geothermal heat recovery or storage device.

Such a method for producing a multilayer pipe or multilayer pipe molding may be selected as an extrusion process or as an injection molding process or as a blowing process or as an in-line fabrication process or as a combined process from the above.

With the aid of the method, a multilayer pipe or a multilayer pipe molding according to the above description can be produced in a favorable manner.

In the context of the invention has proven to be very advantageous when the method is carried out so that the first polymer material forms the lumen limiting layer of the multilayer pipe or the multilayer pipe molding or that the second polymer material, the lumen-limiting layer of the multilayer pipe or forms multilayer pipe molding.

It has proved to be favorable when an additional layer is arranged between the layer of the multilayer pipe or of the multilayer pipe molding and the further layer of the multilayer pipe or the multilayer pipe molding.

The additional layer may be a primer layer or a diffusion barrier layer or a protective layer or a reinforcing layer or a leveling layer or a heat conducting layer.

Arranging a primer layer or a diffusion barrier layer or a protective layer or a reinforcing layer or a leveling layer or a heat conducting layer can be realized in a simple manner in an extrusion process or in an injection molding process.

It is also extremely favorable to arrange an outer layer, which forms the outermost layer of the pipe or pipe molding, in the context of the manufacturing process.

By a corresponding method, in which, in addition to the production of the at least two layers of the multilayer pipe or the multilayer molded part of the polymer materials according to the above description, a heat conducting layer and / or a diffusion barrier layer and / or an outer layer is arranged, is particularly advantageous and advantageous.

In this way, a pipe or pipe fitting with the described complex structure of its wall in a simple manufacturing process, such as a coextrusion or multi-component injection molding without much effort, accessible in high reproducibility and with a superior level of quality.

The object of the present invention is achieved by a pipe arrangement according to claim 8.

A multilayer pipe or multilayer pipe molding, in particular a connecting element, a pipe bend, a pipe branch, a tee, a sleeve or an electrofusion socket are produced using a first and a second polymer material as described above.

In the context of the present invention, the object of providing a pipe arrangement is achieved by claim 9.

The pipe arrangement according to the invention comprises at least one multilayer pipe or at least one multilayer pipe molding according to the described type.

In the context of the present invention, the object of providing a geothermal heat recovery or storage device is solved by claim 10.

The task finds its solution in a pipe arrangement with at least one multilayer pipe or at least one multilayer pipe molding according to the above description.

As a multilayer pipe molding in the above context of the invention, for example, a connecting element, a pipe bend, a branch pipe, a tee, a sleeve or a Electric welding socket understood without this list is exhaustive.

An electric welding sleeve is particularly suitable for connecting pipes with each other or pipes and pipe fittings or pipe fittings with each other. It is understood in the context of the present invention that an electric welding sleeve can be formed so that they can accommodate a pipe, two pipes, three pipes or four pipes and connect with each other or with one or more pipe fittings.

A pipeline consisting of pipes or pipe fittings according to the present invention is particularly advantageous when the connection between the pipes or pipe fittings is made by butt welding or by using welding sleeves.

The invention finds application in the provision of high-quality, low-cost pipes and pipe parts for producing a geothermal probe tube arrangement which has an increased temperature resistance, at the same time high resistance to point loads and slow and rapid crack growth. The pipes and pipe fittings can be joined together at the construction site without any problems by welding techniques.

The borehole heat exchanger tube arrangement can be installed in the ground in horizontal and / or vertical construction. Vertical installation generally produces wells in the ground into which the borehole heat exchanger tube assembly is inserted. A horizontal installation can be done by making trenches for inserting the geothermal probe tube assembly or by plowing derselbigen in the ground.

Other important features and advantages of the invention will become apparent from the dependent claims, from the Fig. And from the accompanying figure description.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are shown in the figures and will be explained in more detail in the following description, wherein like reference numerals refer to identical or functionally identical components.

The invention will be explained by the attached figures as follows.

This shows:

1a a side cross-sectional view of a tube of a first embodiment with a partial removal of the layers;

1b a side cross-sectional view of your tube of a second embodiment with a partial removal of the layers;

2 a longitudinal section through a pipe fitting along the axis.

In 1a is a pipe 1 of a first embodiment shown in a lateral cross-sectional view, wherein the layers are partially removed.

The multilayer pipe 1 has a lumen 2 on, that of a layer 1.1 is limited, which consists of a first polymer material.

This layer 1.1 is with the other layer 1.2 firmly bonded from the second polymer material.

On the lumen 2 of the pipe 1 opposite side of the further layer 1.2 is an outer layer 3 arranged.

All these layers are firmly connected.

In 1b is a pipe 1 of a second embodiment shown in a side cross-sectional view, with the layers partially removed.

The multilayer pipe 1 has a lumen 2 on, that of another layer 1 .2 is limited, which consists of a second polymer material.

This further layer 1.2 is with the layer 1.1 firmly bonded from the first polymer material.

On the lumen 2 of the pipe 1 opposite side of the layer 1.1 is an outer layer 3 arranged.

All these layers are firmly connected.

In 2 is a longitudinal section through a pipe fitting 1' shown in the form of a connecting element (foot of a geothermal probe) along its axis.

The pipe molding 1' in the form of a connecting element, allows a connection from here not shown pipes 1 . 1 with a certain angle, in the present case about 90 °.

The lumen 2 of the pipe molding 1' is bounded by a multilayer wall, the construction being analogous as described above 1a portrayed. All reference numerals correspond to each other.

All figures are schematic and not to scale, they show the basic structure of the tubes and pipe fittings of the present invention.

LIST OF REFERENCE NUMBERS

1

pipe

1'

Pipe fitting

1.1

layer

1.2

another layer

1.3

additional layer

2

Lumen of pipe or pipe molding

3

outer layer

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• ISO 9080 [0008]
• ISO 16770 [0008]
• ISO 1167-1 [0009]
• ISO 1167-2 [0009]
• ISO 9080 [0020]
• ISO 16770 [0022]
• ISO 9080 [0033]
• ISO 16770 [0033]

Claims (10)

Use of a first polymer material which is an uncrosslinked polyolefin and, in an internal pressure test according to ISO 9080, has an internal compressive strength which lies on or above a reference curve in the temperature range from 10 to 110 ° C, which corresponds to the following definition: lg t = -219 - (62600.752 × lg sigma) / T + 90635.353 / T + 126.387 × lg sigma where t is the time in h, T is the temperature in K and sigma is the hydrostatic stress in MPa, to produce at least one layer ( 1.1 ) of a multilayer pipe ( 1 ) or at least one layer ( 1.1 ) of a multilayer pipe molding ( 1' ) and a second polymer material which is an uncrosslinked polyolefin and has a minimum required strength (MRS) of> 10 MPa and an ISO 16770 FNCT at 80 ° C and sigma 4 N / mm ² at 1% Arkopal of> 10,000 h, for the production of at least one further layer ( 1.2 ) of a multilayer pipe ( 1 ) or at least one further layer ( 1.2 ) of a multilayer pipe molding ( 1' ) for a pipe assembly of a geothermal heat recovery or storage device.  Use of a first and a second polymer material according to claim 1, wherein the first polymer material and / or the second polymer material is a polyethylene. Use of a first and a second polymer material according to claim 1 or 2, wherein the first polymeric material comprises the lumen ( 2 ) limiting layer ( 1.1 ) of the multilayer pipe ( 1 ) or the multilayer pipe molding ( 1' ) or wherein the second polymer material forms the lumen ( 2 ) limiting layer ( 1.2 ) of the multilayer pipe ( 1 ) or the multilayer pipe molding ( 1' ). Use of a first and a second polymer material according to one of the preceding claims, wherein between the layer ( 1.1 ) of the multilayer pipe ( 1 ) or the multilayer pipe molding ( 1' ) and the layer ( 1.2 ) of the multilayer pipe ( 1 ) or the multilayer pipe molding ( 1' ) an additional layer ( 1.3 ) is arranged. Use of a first and a second polymer material according to claim 4, wherein the additional layer ( 1.3 ) is a primer layer or a diffusion barrier layer or a protective layer or a reinforcing layer or a leveling layer or a heat conducting layer. Use of a first and a second polymer material according to one of the preceding claims, wherein an outer layer ( 5 ), which is the outermost layer of the tube ( 1 ) or pipe molding ( 1' ) is arranged. Use of a first and a second polymer material according to any one of the preceding claims, wherein at least one of the layers ( 1.1 . 1.2 . 3 ) is modified. Multilayer pipe ( 1 ) or multilayer pipe molding ( 1' ), in particular a connecting element, a pipe bend, a pipe branch, a T-piece, a sleeve or an electric welding sleeve, produced using a first and a second polymer material according to one of claims 1 to 7. Pipe arrangement with at least one multilayer pipe ( 1 ) or at least one multilayer pipe molding ( 1' ) according to claim 8. Geothermal heat recovery or storage device comprising a tube assembly having at least one multilayer tube ( 1 ) or at least one multilayer pipe molding ( 1' ) according to claim 9.

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