The concept of pre-insulated pipes aims to transport the conveyed media with unchanged thermal properties. The origin of the structural design lies in the technology of district heating pipelines, the aim of which is to transport heat over long distances. The main factors influencing the design and layout of the respective pipe system are the technical specifications of the system operator, processing instructions during installation, and the climatic conditions on site.
The concept
The concept for pre-insulated pipes from Jabitherm Rohrsysteme AG follows a simple principle: medium pipe - thermally insulating insulating foam - outer jacket. The physical properties of polyurethane foam insulation fit perfectly into the concept of pre-insulated piping systems. Polyurethane (PUR) has enormous adhesive power to forcefully "glue" the surface of the medium pipe and the outer jacket. This property creates a composite system that offers many advantages in the pipeline route. The connection between the medium pipe and the outer jacket is so strong that the components act as a single unit. In contrast to conventionally insulated pipes, the installation of pipe holders on the outer jacket is easily possible with the Jabitherm system.
1. Medium pipe
The medium pipe can be selected from a variety of materials. The resistance can be adjusted to the chemical reactions of the liquid or gas. Together with the foam insulation made of polyurethane, either standard or flame-retardant, the pre-insulated pipe meets almost all operational requirements. The large selection of outer jacket materials gives engineers and system builders the opportunity to set a counterpoint against aggressive substances from the surrounding atmosphere.
2. Thermal insulation layer
The combination of sturdy and energy-efficient foam insulation and a medium pipe that is tailored to the properties of the transported product ensure safe operation, continuous material flow, protection against condensation and a long service life. Due to the automated manufacturing process of the thermal insulation between the medium pipe and the outer jacket, a uniform insulation effect can be achieved over the entire length of the pipeline. With a thermal conductivity (λ) of 0.027 W/mK (at 20°C (68 F), 70 kg/m³), polyurethane offers optimal insulating properties. Also available is a self-extinguishing fire protection foam for areas at risk of fire.
3. Outer jacket
The most effective way to create a thin-walled protective jacket is with a so-called spiral-seam pipe. The focus of these spiral folding pipes is on the internal spiral fold, which is produced using a specially designed spiral folding machine and with a pressure of ~ 50 bar. The defined shape of the spiral fold forms a labyrinth seal, which significantly increases the flow resistance by extending the flow path and thus enables diffusion tightness. Through decades of experience, Jabitherm has perfected the process for producing this spiral fold and can therefore ensure the longevity of the diffusion tightness. The diffusion density of the Jabitherm series prevents the penetration of moisture and unwanted exchange with the surrounding atmosphere. In order for this to be possible over a period of years and decades, a diffusion resistance number (µ) of > 1,000,000 is generally assumed. In independent tests by the German Materials Testing Office (MPA), Jabitherm products were able to demonstrate a diffusion resistance number of ~ 1,200,000 in a long-term test, which means the product can be described as diffusion-tight.
Wrap fold
Wrap fold (scheme)
ADVANTAGES
Fixed and sliding points
Fixed and sliding points can be mounted on the outer jacket
no heat/cold bridges, no corrosion Impact-resistant insulation
Longevity, low maintenance costs
High level of prefabrication
quick installation
Reduced effort for scaffolding and reduced safety risk on site Low insulation thickness with constant heat transfer
increased pipe volume in the pipe bridge
Best possible insulation values
Best possible insulation values (λ)
reduced energy loss
reduced CO2 emissions
Diffusion-tight spiral fold jacket
no ice formation,
no condensation
Force-fitting polyurethane composite system
large span for support points
Minimal insulation effort on site
reduced installation time