Rigid pipe system
Twin pipe – Straight pipe
The ISOPLUS twin pipe is the effective complement to the single pipe and is also supplied longitudinally or spirally seam-welded and seamless in accordance with the highest quality standards (standard material: P235GH, other steel grades or materials upon request). We produce the twin pipes in accordance with DIN EN 253 and AGFW FW 401 in both classic and continuous design. They are the perfect solution for transporting district heating and cooling to the consumer with optimised ecological and economic benefits (especially regarding construction work and heat loss).
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Local- and district heating
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Local- and district cooling
Product information
ISOPLUS twin pipes consist of two steel pipes, polyurethane insulation
and a stroke- and break-resistant PEHD outer casing. All components together form a robust compound system. The polyurethane foam used for the insulation is foamed with a blowing agent from the pentane group, thus ensuring an optimum insulation value and high compressive strength.
Specifications for special steel pipes can be requested from our technical department. All fittings are manufactured in accordance with the requirements of DIN EN 13941-1.
Note: For nominal diameters DN 25 to DN 65, we only supply steel pipes and fittings with a wall thickness of 3.2 mm. This must be taken into account when comparing the competition!
Key-features
- Series production in sizes DN 20 (3/4") to DN 250 (10")
- Available as 6, 12 or 16 m tubular rods, special lengths upon request
- Operating temperature at least according to DIN EN253, standard pressure 16 bar but 25 bar also possible
- Carrier pipe standards: DIN EN 10216, DIN EN 10217-1 + 10217-2 and DIN EN 10217-5, wall thicknesses according to DIN EN 253/ AGFW FW 401
- Continuous operating temperature 120 °C, 140 °C possible for max. 300 hours per year
- Rigid polyurethane foam insulation (thermal conductivity λ50 = 0.027 W/(m-K) and λ50 = 0.023 W/(m-K) for pipes with diffusion barrier in continuous production) available in insulation series 1, 2 and 3 (DN 250 in discontinuous production only available in insulation series 1 and 2)
Discontinuous and continuous production
Discontinuous Production
In discontinuous production technology spacers are fixed to the carrier pipe to which leak detection wires can be attached. The pipe prepared in this way is then inserted into the outer casing and the annular gap at the pipe ends is sealed with foam caps. The pipe is then clamped to the foaming table and the PUR foam is mixed at ~130 bar at one end of the pipe using an electronically-controlled mixing head and injected into the pipe.
Following the development of rigid pipes, this procedure has become established as the most common production process and is listed as a technical standard in all the applicable specifications and guidelines. In the production process of fittings such as bends, branches, etc., only this method is used.
We can produce the following sizes using this process:
Single pipes DN 20 to DN 1000, twin pipes DN 20 to DN 250, all fittings
Continuous Production
In continuous production technology the tubular steel rods are sandblasted in the first step of the production line and then coupled together mechanically. This string of pipes will then receive the leak detection wires, the polyurethane insulation layer, a diffusion barrier-foil, and the extruded polyethylene outer casing in a continuous and CNC-controlled process. The barrier-foil consisting of an aluminium compound material prevents diffusion of the PUR cell gas through the PE outer casing. A special coating of this barrier-foil ensures that the minimum shear strength required in accordance with DIN EN 253 is exceeded and that the basic or compound principle of the friction-locked construction method for rigid pipes remains intact.
The diffusion barrier layer, which we insert between the foam and the protective casing, reliably prevents the insulation system from ageing - the optimised insulation properties therefore remain virtually constant over the entire service life of the pipe. For the operation of a district heating network, this provides an optimum basis for keeping energy efficiency high and heat losses and CO2 emissions low on the generator side. The positive effects on our environment as well as for the expenses for network losses during the total lifetime are considerable.
We can produce the following sizes using this process:
Single pipes DN 25 to DN 200, twin pipes DN 20 to DN 100
Product Specifications
Continuous: DN 25 to DN 100, discontinuous: DN 20 to DN 250
Maximum operating pressure 16 bar according to DIN EN13941, 25 bar upon request
Technical delivery conditions according to DIN EN 253
Test certificate according to DIN EN 10 204-3.1
Free pipe end: 220 mm ± 10 mm
The axial shear strength of the pipe (between the steel pipe, PUR and the outer casing) is at least 0.12 N/mm² according to DIN EN 253
Outer casing made of seamlessly extruded PEHD 100 (density: over 940 kg/m³, melt flow index: 0.2-0.7g/10 min., 5 kg in accordance with ISO 1133, elongation at break: min. 350 %)
Corona treatment to optimise the joint properties in discontinuous production
Compressive strength of the insulation: ≥ 0.3 N/mm² according to DIN EN 253
ISOPLUS pipes and components are supplied as standard with IPS-Cu (two integrated copper wires 1.5 mm²) for leak detection (IPS-NiCr or other systems are also available on request in some countries)
Please let us know if you have any questions about our products.