Preinsulated system for temperatures above 145°C

Posted in Production range

Pre-insulated piping system for temperatures above 145°C is designed as so called sliding system. The carrier pipe expands within insulation without jacket moving in the ground. Expansion is absorbed by bends end expansion joints. The system can be installed above or under the ground.

The design of the sliding system is technically demanding, please consult with us any technical queries. 

 
Predizolovaný systém - para
 

This system is used for distribution:

  •          steam
  •          any media with temperature above 145°C up to 300°C

 

Service pipes

Welded steel pipes  P235GH EN 10217-2 , EN 10217-5 (DIN 1626), or seamless steel pipes P235GH according toEN 10216-2 (DIN 1629).

Dimension standard: EN 10217-1 (DIN 2448)  
Material: P235GH (St 37.0)
Certificate: EN 10204 – 3.1 B
Tests: non destructive
Bevels: DIN 2559/22
Lengths: 6 000 mm, or 12 000 mm

 

Density 7850 kg/m3
Elasticity 206 000 N/mm2
Characteristic stress 225 N/mm2
Strength tensile 350 N/mm2
Thermal conductivity 46 - 54,5 W/mK
Thermal extensibility 0,12 . 10-4K-1

 

Mineral wool

The mineral wool is used in a form of compressed, or grained shaped blocks:

Product  NOBASIL PVT 
Compression  strength  50 kPa
Thermal conductivity < 0,040 W/(m K)
Permanent thermal conductivity 230°C
Technical delivery conditions: PN 117 - 72 - 87
   
Product  RBP 18  
Density 170 kg/ m3 ± 10%
Thermal conductivity < 0,044 W/(m K)
Permanent thermal resistivity 750°C
Technical delivery conditions: DIN 181 65
   
Centringable lamellar segments LSP  
Density >50 kg/m3 for supplementary insulations

 

 

Polyuretane foam  – PUR

Properties according to standard EN 253, calculated continues operating temperatures 140°C for 30 years. Maximum short operating temperature: 150°C.

Specific weight of grain (EN 253, čl. 4.3.3.1) > 60 kg/m3
Total specific weight (EN 253, čl. 4.3.3.2) > 80 kg/m3
Thermal conductivity < 0,027 W/(mK)
Water absorption    ≤ 10%
Compression radial strength at 10% compression min 0,3 MPa
Sheering axial strength before and after ageing at 23 ± 2°C min. 0,12 MPa
  at 140 ± 2°C min. 0,08 MPa

 

Jacket HDPE  pipe

For underground application HDPE jackets with corona-treated surface are used. This ensures an optimum adhesion between outer casing and insulation.

Density 960 kg/m3 (+20°C)
Thermal tensibility coefficient 180.10/°C
Melt flow rate (MFR 190/5) 0,35 ÷ 0,65g/10 min
Thermal conductivity 0,43 W/mK
Strength tensile ≥ 17 MPa

 

Jacket pipe SPIRO

For aboveground systems jacket pipes made of spiral coiled galvanized steel  (aluminium) belt (according to PA 12 0314, or DIN 24 145) are used.

 

Sliding system designing

All the basic designing principles of bonded system (up to 145°C) are applied for sliding system. The sliding piping system is delivered as one functional unit, please consult with us all construction parameters, mainly expansion issues.

 

Thermal losses

This data can be found in COMPONETS section, where it is stated the loss per 1 m of piping / 1°C, assuming underground application, soil temperature 8°C and soil lambda 1,5 W/m/°K.

Thermal dilatation compensation

For calculation of thermal extension of service pipe , the same principals are used as for bonded system. Please take into consideration possible sudden temperature changes of steam and mechanical stresses in the system.Compensation components as permanently working axial compensators or dilatation elbows are used in the pipeline to absorb expansion. Dilatation elbow are special components, in which carrier pipe is separated from insulation layers and can freely move inside the component.

 
When calculating axial forces, it is necessary to take into consideration the friction force between carrier pipe and sliding layer  - value is set to 10kPa by internal standard PIPECO N03-97. The value of friction stress is applied to perpendicular projection of  service pipe in dilatation section. Another force element in dilatation section between two anchors is created by resistance of axial compensator (if used) and this value is stated by compensator manufacturer as force per 1mm of compensator compression. Calculation of expansion section is based on above mentioned parameters and the stress in service pipe must not exceed allowed value 150 MPa.

 

The installation

The installation is done without pre-heating. No compensation pads are used in elbows. Because the carrier tube is permanently moved axially into the compensator, it is necessary to ensure that the influence of axial forces prevent carrier tube buckling and ultimately jamming compensator. Therefore, in the prescribed distances in front of  axial compensator,  bitumen cardboard is wrapped around casing HDPE pipe to protects the casing from damage during micro-movements.