CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application of International Patent Application No. PCT/EP2017/067419, filed on Jul. 11, 2017, which claims priority to Swiss Patent Application No. 00937/16, filed on Jul. 20, 2016, each of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD OF THE INVENTION

The invention relates to pipe systems containing a thermal insulation, in particular thermally insulated medium pipes, and also thermally insulated cover devices or bushings for connecting conduit pipes having improved thermal insulation. Furthermore, the invention relates to methods for producing such devices and also the use of polymer foams which contain hydrofluoroolefins (HFO) in such devices and for producing such devices. Finally, the invention relates to the use of HFO as a cell gas in thermal insulations.

BACKGROUND OF THE INVENTION

Pipe systems containing a thermal insulation, also called pre-insulated pipe systems or thermally insulated pipe systems, are known and proven per se. Such pipe systems comprise flexible or rigid medium pipes, which are enclosed by a thermal insulation, which is in turn enclosed by a jacket, and also possibly bushings and/or cover devices. Depending on the construction, these pre-insulated pipe systems are also referred to as a plastic medium pipe system (PMP) or plastic jacketed pipe system (PJP). In the first, the medium pipes used have a certain flexibility, so that the entire composite can also be wound onto drums with a certain application of force. These are therefore also referred to as flexible pipe systems. In the latter, the medium pipes used are not flexible, therefore, reference is also made to rigid pipe systems in the case of the overall composite. Accordingly, thermally insulated medium pipes or conduit pipes having one or more thermal insulation layers are known; as is the production thereof. Thus, methods for the continuous production of thermally insulated medium pipes are known from EP0897788 and from EP2213440. A method for producing individual, rigid pipe sections is known from EP2248648.

In such pipe systems, the foam (for example, polyurethane, PU) generally used as an insulation material changes its composition of its cell gases in the course of time. This takes place due to diffusion of nitrogen and oxygen from the surroundings into the foam and due to diffusion of the foam gases and/or cell gases originally contained in the foam, in particular carbon dioxide and other blowing agents, out of the foam. The air gases have a significantly higher thermal conductivity than the originally contained carbon dioxide and the other typically used blowing agents.

Integrating so-called barrier layers into the outer jacket has been proposed to minimize these diffusion processes.

Metallic layers can be used as the barrier layers. If metallic layers are used, not only is the gas exchange completely suppressed, which is desired, but rather water vapor is also completely prevented from diffusing. This is problematic in particular in the case of the use of medium pipes made of plastic, since water typically flows through them as the medium, because of which water vapor, although also only a small quantity, continuously migrates through the walls thereof. This water vapor has to have the possibility of penetrating outward and/or coming into equilibrium with the surroundings, since otherwise water becomes enriched in the thermal insulation of the thermally insulated conduit pipe in the course of time, whereby the thermal conductivity significantly rises and the risk exists that the thermal insulation will become damaged in the long term.

Layers which consist of one or more polymer materials can be used as barrier layers. Thus, EP1355103 describes thermally insulated conduit pipes which contain a barrier layer made of ethylene vinyl alcohol (EVOH), polyamide (PA), or polyvinylidene chloride (PVDC). Furthermore, EP2340929 describes a plastic jacketed pipe, the outer jacket of which is formed as a multilayer pipe and which has a gas permeation barrier layer (“barrier”) in its interior. The pipes described in these documents are difficult to produce and/or have an inadequate insulation capability. Conduit pipes having thermal insulation and a polymer barrier layer are known from CH710709 (post-published) and WO2004/003423; these polymers contain polyketones and/or EVOH.

Molded parts and connecting pieces are used for connecting thermally insulated pipes. In particular, cover shells are used as molded parts, as described in WO2008/019791. Or bushings are used as connecting pieces, in particular in the case of the connection of rigid pipes. The mentioned problems also arise in the case of such molded parts and connecting pieces.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a thermally insulated conduit pipe and also molded parts and connecting pieces which do not have the mentioned disadvantages.

The objects outlined above are achieved according to the independent claims. The dependent claims represent advantageous embodiments. Further advantageous embodiments can be inferred from the description and the figures. The general, preferred, and particularly preferred embodiments, ranges, etc. provided in conjunction with the present invention can be combined with one another as desired. Individual definitions, embodiments, etc. can also be omitted and/or can be nonrelevant.

The present invention will be described in detail hereafter. It is apparent that the various embodiments, preferences, and ranges disclosed and described hereafter can be combined with one another as desired. Moreover, individual definitions, preferences, and ranges may not be applied depending on the embodiment. Furthermore, the term “comprising” includes the meanings “containing” and “consisting of”.

The terms used in the present invention are used in the generally typical meaning routine to a person skilled in the art. If no other meaning results from the direct context, the following terms in particular have in this case the meaning/definitions indicated here.

