Large plastic pipe technology Large diameter pressure pipe up to DN/ID 5000 mm
Powerful and designed according to YOUR specifications
Large diameter pressure pipes No sagging and less wallthickness saves a lot of material and money for you. 1. Introduction The today s demand for large diameter pressure pipes made out of thermoplastics is steadily increasing. Especially for the transport of potable water, piping systems in water treatments, intake and outfall lines the market is strongly looking for corrosion resistant solutions with the same characteristics in durability and safety, as they are used in small dimensions with polyethylene. The traditional production technology faced some difficulties for large diameters and big wall-thicknesses, like sagging of the material, frozen stresses, missing jointing technology and missing fitting program. That was the reason why Krah decided several years ago to develop a polyethylene pipe system for pressure pipe application up to 10 bar / 16bar, for water only. The Krah pressure pipe system is based on the helical extrusion process. Together with the Krah Comtruder -technology and other Krah innovations there are almost no limitations in wallthickness, diameter and in the recipe of raw materials. Even reinforcements like glassfibers can be added if required. The success of the last years, since the Krah pressure pipes system has been introduced on the market, confirms and underlines the Krah strategy to invest in new technologies to open the market of large diameter pressure pipes for thermoplastic materials.
2. Specification 2.01 Material Polyethylene PE100 and glass-fiber reinforced polyethylene PE-GF200 have excellent properties for the application of water supply, as well as for the fabrication of containers for liquids and solid materials. All the materials are environmentally friendly. Pressure pipes produced in PE80, PE100 are manufactured with the KR-production and BH-production line, pipes produced with PE-GF200 can only be produced with a KDR-production line. High density polyethylene (PE100) Polyethylene PE100 reinforced with glass fiber (PE-GF200) PE-GF200 is a compound and has a minimum MRS value of 20 N/mm², compared to pure PE80 with an MRS value of 8 N/mm² and PE100 with MRS of 10 N/mm². These materials feature the below-mentioned properties. Other materials can be used after prior acceptance of the producer and a third party for quality control. However, the processed material should have the below-listed specifications. Material mix Property Standard Unit PE 100 PE-GF200 MRS class ISO 12162 N/mm² 10 20 Density ISO 1183 g/cm³ 0.96 1,02-1,09 melt index ; MFR 190/5 ISO 1133 g/10 min 0,25 depends from recipe Tensile modulus (1 min) ISO 178 N/mm² 1100 2500 Tensile strength at yield (in Extrusion-direction) Tensile strain at yield (in Extrusion-direction) Notch resistance / Slow crack growth behavior ISO 527-2 N/mm² > 23 > 35 ISO 527-2 % >8 > 4 EN 12814-3 80 C,4 MPa, Arkopal N100 > 300 >1000 h Thermal expansion DIN 53752 1/ C 1.8 x 10-4 < 0,5*10-4 Colour black/yellow/blue black/yellow/blue
2.02 Pipe Diameter Krah pressure pipes can be produced steplessly at intervals of 100mm with internal diameters (ID) from DN/ID 300mm to DN/ID 5000mm. The nominal diameters (DN) coincident with the internal diameter (ID) of the pipe. In case of any change in the design of the pipe the wallthickness can be increased or reduced while the internal diameter remains the same. This ensures that the designated hydraulic capacity for the installation is maintained. 2.03 Pipe length The standard laying length of the Krah pressure pipes is six meters, because in this way they are easy to handle, store and transport. In addition it is possible to continuously produce any length between one and six meters. The longer a pipe is the fewer joints are necessary and this is advantageous for the installation of the pipe. Moreover it is possible to deliver the pipes already jointed, whereby the installation time on site can be reduced significantly. Lengths up to 18m consisting of 3 pipe sections are common. 2.04 Surface The internal and the external surface of the Krah pressure pipes are smooth. Slight corrugation on the outer surface, which necessarily involves variations in the wall thickness, is acceptable providing that the thickness of the pipe wall is at no point less than its given nominal value. The inner and the outer surfaces can be produced of electro- conductive or coloured material. 2.05 Weldability Due to the properties of thermoplastic material the pipes can be welded together which signifies, that the whole pipeline builds a homogenous system and is absolutely safe against infiltrations and exfiltrations. For joining the Krah pressure pipes we recommend either the proven Krah Electro-fusion-technology or the traditional butt-fusion-process.
2.06 Chemical resistance Thanks to the used material Krah pipeline systems guarantee an optimum security regarding chemical resistance. That is especially important for all industrial applications and for pipelines in contact with sewage, where the biogenous sulphuric acid corrosion plays a key role regarding the durability of the system. But also normal buried pipes for potable water can be affected from the outside, due to soil contamination. 2.07 Impact resistance The high impact resistance, even at low temperatures, ensures a robust pipe, resistant against impacts during transport, installation on site and during the whole service life conditions. 2.08 Recycling Polyethylene can be recycled to 100%. This material has the property to be reworkable without the structure of the material having to be modified dramatically. For this reason all waste material of polyethylene pipes can be led back into the production cycle. Only for potable water it is recommended to use 100% virgin material. And the smooth surface of Krah pipes will protect the pipe against rodents and other animals. 2.09 Hydraulics Inner diameter and hydraulic properties of Krah pipes will remain constant regardless of the wall thickness or the profiles due to the smooth anti-adhesive inner pipe surface. The nominal diameter (e.g. DN/ID 500) corresponds to the respective inner diameter according to DIN 16961. Compared to other pipe materials like concrete, smaller diameters can be used, which means that costs for material and installation can be reduced considerably. 2.10 UV-resistance Black polyethylene pipes are permanently resistant to atmospheric corrosion and UV radiation. Thus the pipes can be used and stored outside without the pipe material being damaged. No aging effect will occur. 2.11 Norms and standards The Krah piping system is designed to meet the requirements of present applicable international norms and standards. The Krah GmbH is a member of the major standardization committees to guarantee that the pipes are corresponding to the standards, but also that the standards are corresponding to the pipes. The Krah pressure pipe corresponds to the following international standards: PE-GF200: DIN SPEC 19674-1 DIN SPEC 19674-2 ISO/CD 29561 ASTM F2720 PE 100: ISO 4427 DIN 16961 DIN PAS 1065 SPEC 14001
3 Dimensions Generally our pipes can be produced with a wall thickness of 5 mm up to 250 mm. The complete wall thickness is homogenous. If requested the inner surface can have a co-extruded alternative colour. 3.1 Krah pressure pipes made out of polyethylene PN 4 PN 6 PN 8 PN 10 PN 12,5 SIDR 39 / SDR 41 SIDR 24 / SDR 26 SIDR 19 / SDR 21 SIDR 15 / SDR17 SIDR 11,6 / SDR 13,6 Inner Diameter e Weight e Weight e Weight e Weight e Weight DN/ID [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] 500 12,8 19,8 20,8 32,7 26,3 41,8 33,3 53,6 43,1 70,6 600 15,4 28,6 25,0 47,1 31,6 60,2 40,0 77,2 51,7 101,7 700 17,9 38,9 29,2 64,2 36,8 81,9 46,7 105,1 60,3 138,4 800 20,5 50,8 33,3 83,7 42,1 106,9 53,3 137,3 69,0 180,7 900 23,1 64,2 37,5 106,0 47,4 135,3 60,0 173,7 77,6 228,7 1000 25,6 79,3 41,7 131,0 52,6 167,1 66,7 214,5 86,2 282,4 1100 28,2 96,0 45,8 158,3 57,9 202,2 73,3 259,5 94,8 341,7 1200 30,8 114,2 50,0 188,5 63,2 240,6 80,0 308,8 103,4 406,7 1300 33,3 134,0 54,2 221,4 68,4 282,4 86,7 362,4 112,1 477,3 1400 35,9 155,5 58,3 256,4 73,7 327,5 93,3 420,4 120,7 553,5 1500 38,5 178,5 62,5 294,5 78,9 375,9 100,0 482,5 1600 41,0 203,0 66,7 335,3 84,2 427,7 106,7 549,0 1800 46,2 257,0 75,0 424,1 94,7 541,4 120,0 694,9 2000 51,3 317,3 83,3 523,4 105,3 668,3 2200 56,4 383,9 91,7 633,8 115,8 808,7 2400 61,5 456,9 100,0 754,0 2600 66,7 536,2 108,3 884,6 2800 71,8 621,8 116,7 1027 3000 76,9 713,8 125,0 1178 3500 89,7 971,6 4000 102,6 1269 Bigger diameters on request!
3.2 Krah pressure pipes made out of glass fibre reinforced polyethylene PN 6 PN 8 PN 10 PN 12,5 PN 16 SIDR 39 SIDR 30 SIDR 24 SIDR 19 SIDR 14,5 Inner Diameter E Weight e Weight e Weight e Weight E Weight DN/ID [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] [mm] [kg/m] 500 12,8 22,5 16,7 29,5 20,8 37,2 26,3 47,4 34,5 63,1 600 15,4 32,5 20,0 42,5 25,0 53,5 31,6 68,3 41,4 90,9 700 17,9 44,0 23,3 57,7 29,2 72,8 36,8 93,0 48,3 123,8 800 20,5 57,6 26,7 75,6 33,3 95,1 42,1 121,4 55,2 161,7 900 23,1 73,0 30,0 95,5 37,5 120,4 47,4 153,7 62,1 204,6 1000 25,6 89,9 33,3 117,8 41,7 148,6 52,6 189,7 69,0 252,6 1100 28,2 108,9 36,7 142,9 45,8 179,8 57,9 229,6 75,9 305,6 1200 30,8 129,8 40,0 169,8 50,0 214,0 63,2 273,2 82,8 363,7 1300 33,3 152,0 43,3 199,2 54,2 251,2 68,4 320,6 89,7 426,9 1400 35,9 176,5 46,7 231,4 58,3 291,3 73,7 371,8 96,6 495,1 1500 38,5 202,8 50,0 265,4 62,5 334,4 78,9 426,9 103,4 567,7 1600 41,0 230,4 53,3 301,8 66,7 380,5 84,2 485,7 110,3 646,0 1800 46,2 292,1 60,0 382,2 75,0 481,5 94,7 614,7 124,1 817,7 2000 51,3 360,3 66,7 472,0 83,3 594,5 105,3 758,9 2200 56,4 435,8 73,3 570,6 91,7 719,3 115,8 918,2 2400 61,5 518,4 80,0 679,4 100,0 856,1 2600 66,7 609,1 86,7 797,7 108,3 1005 2800 71,8 706,1 93,3 924,4 116,7 1165 3000 76,9 810,2 100,0 1062 125,0 1338 3500 89,7 1102 115,7 1433 4000 102,6 1441 Bigger diameters on request!
3.3 Calculation of the wall thickness The Krah pressure pipe system can withstand a working pressure of up to 10 bar, depending on the thickness of the homogenous solid wall (e). Equivalent to ISO 4427 the hoop stress formula can be used with solid wall thickness. e = minimum wall thickness p = internal pressure di = internal diameter σ = permitted strength (MRS/C) MRS = Minimum Required Strength (10 MPa for PE100 and 20 MPa for PE-GF200) C= Safety Factor (for water 1,25 for PE100) C= Safety Factor (for water 1,6 for PE-GF200) Standard Inside dimension ratio (SIDR) Traditionally the standard dimension ratio was used for accurate description of polyethylene pressure pipes. SDR is the relation between the outside diameter and the wall thickness. For inside calibrated pipes, like Krah pipes, it is more useful to specify the SIDR the Standard Inside Dimension Ratio. Formel SIDR = ID e ; SIDR = SDR-2 3.4 Fittings All fittings are fabricated from Krah pressure pipes. Generally the fittings are designed corresponding to the required working pressure and in consideration of the welding factors. Every fitting can have any kind of pipe end and can be assembled with the existing pipe system with any jointing technique. 3.5 Bends Bends can be manufactured and segmented in different angles and the related radius of the bend to the pipe diameter can be selected independently.
The main application is the transporting of water from one place to another and the distribution of water. Production Butt-fusion on site ID 1200, PN 10 Pressure pipe ID 1700, PN 6 Sea outfall ID 1600, PN 5 Pressure testing ID 1900, PN 6 Supply line for water treatment plant ID 3600, PN 10 Pressure pipe ID 1200, PN 10 Prefabrication to 12m length ID 1700, PN 6
4. Production Technology The principle of the production is based on the Krah spiral wound pipe production technology, where an extruded band will be helically wound around a heated mandrel. To produce standard polyethylene pressure pipes a regular single screw extruder can be used. In case that the production line should produce polyethylene pipes re-in forced with glass fiber, to produce a compound called PE- GF200, a Krah Comtruder is needed instead of a single screw extruder. A COMTRUDER is a combination of compounder and an extruder. The so-called inline compounder and extruder can directly mix different kinds of materials and it can build up the extrusion pressure to use it for a pipe production. To produce these kinds of pipes you need a DR-line, in case you want to produce also profiled pipes you need to have a KDR-line. Legend: 1 Inlet for basic material, with a gravimetric system 2 Inlet for glass fiber, with a gravimetric system 3 Inlet for re-worked material, with a gravimetric system 4 Inlet for bonding agent, with a gravimetric system 5 Inlet for colored material, with a gravimetric system 6 Die head 7 KDR-upgrade 8 Production tool 9 Control unit v1 rotation speed of the mandrel v2 production speed In detail, in the Comtruder different materials (1) (2) (3) (4) will be mixed without high pressure in a double co-rotating screw (C). The glass fibres will be fed to the compounding system in a side feeder (B). The extrusion pressure will be build up (D). In the die head the next material (coloured virgin PE100) will be added. All material feeding systems are equipped with the latest gravimetric system and harmonized by a Krah control unit.
Cross winding: The turning mandrel is moving up and down the Comtruder, and so during this cross-winding the complete wall thickness will be build. The machine is producing in both directions. Before the next layer will be comtruded the previous layer will be pre-heated by an IR-heating system so that it is secured that the layers will be homogenous (refer the foto). The complete production process is controlled via an IR-video-camera and the pre-heating system is also controlled completely. Co-Extruder: If required the inner or the other surface of a pipe can be coloured. This coloured surface is done via an integrated co-extruder. In-line socketing The KDR and the DR Series are designed to implement several different jointing methods directly into the pipe during the pipe production process, like for example the unique Krah electro-fusion joint, but also commonly used methods as a flange system. Thanks to the flexibility of the KDR and DR Series, a separate socket machine or a special machine to form parts is not needed. Thus the manufacturing facility allows producing most engineering designs, all of which helps to keep the overall investment low. Output: up to 1000 kg/hr Required space: 20m x 30 m Only one co-extruder can produce a coloured inside and also outside surface of the pipe.
Krah Group Betzdorfer Straße 8 57520 Schutzbach / Germany Tel. +49 (27 41) 97 64 44 Fax +49 (27 41) 97 64 85 Internet www.krah.net e-mail info@krah.net