UVA Light-Curing Brochure (PDF 382 KB)

Light protectionexternal foil (styrene-proof)External foil wrappingn-wrappings glassfiber composite,resin-impregnatedStyrene-proof internal foil(removed after curing)Brandenburgerwww.brandenburger.deTrenchless rehabilitationBrandenburger sets the standardsUV Light CuringBrandenburger liners in all diameters (circular: DN 150 to DN 1000; egg-shaped: 200/300 to 700/1050) are hardened with UV light.Special light initiators in the resins react to UV light at specific wavelengths. For more than 10 years this procedure has been used aroundthe world to safely and permanently rehabilitate sewers.The Brandenburger liner consists of a duroplastic polyester and a reinforcing glass fibre composite from which a seamless liner is made.Selecting suitable materials is of crucial importance for UV light curing. An important factor in this is the optical refraction index, whichspecifies how the material refracts impinging light. A prerequisite for the success is the quality and the precise effective combinationof liner material, resins, and UV light technology. At Brandenburger everything comes from one source.Light curingUV light curing has generally been applied industriallyfor over 30 years, for instance for curing paints inthe automobile industry. This curing technology hasalso been used for sewer rehabilitation since theend of the 1980s.For the light curing of the resins, radicals are neededthat can induce the polymerisation. Exposure to UVlight causes these photoinitiator molecules to de-compose into the radicals that are needed for thepolymerisation process. These induce polymerisationby interlinking with the styrols contained in theresin. For this, special photoinitiators are added tothe resins, which decompose into colourlessproducts when exposed to UV light.The resinsIn the Brandenburger resins used, unsaturatedpolyester resins (UP resins) and vinylester resins(VE resins) have proven their worth in sewerrehabilitation for over 10 years. In municipal sewersgenerally a UP resin (acc. DIN 18820 group 3, type1140 or EN 13121 group 4) and for aggressiveindustrial sewage a special VE resin (acc. DIN18820 group 5; type 1310 or EN 13121 group7A) are used for impregnating the GFRP composites.The reaction resin mass is manufactured byBrandenburger with a customised procedure withconsistent quality. In a like-wise customised andpatented procedure it is infused extremely evenlyinto the seamless glass fibre composite. This afterall is what makes it possible for the applied UVlight sources to cure evenly and controlled.The glass fibre compositeA special glass composite made of ECR glass fibrequality Advantex is used for the Brandenburgerliner. The developed homogenous base materialwith high optical refraction index in combinationwith the special resin mixture already fulfillssignificant conditions for the even curing of theliner material. This shows the advantages of theBrandenburger liner compared to liners in sandwichconstruction or with synthetic fibres as base material.The high transparency of the resins, glass fibres,and foils used in the Brandenburger liners areimportant conditions for even curing.polymerradicalphotoinitiatorUV lightmonomerComposition of the linerwww.brandenburger.deBrandenburger Liner GmbH & Co.Taubensuhlstraße 6D - 76829 Landau/PfalzTel. +49 63 41 / 51 04 -0Fax +49 63 41 / 51 04 -155Technical equipmentIn addition to the glass fibre composite used andthe composition of the resin the technicalequipment for the UV light curing is the thirdcrucial factor for the quality of a rehabilitationwith light-curing GFRP inliners. The most importantcriteria are the intensity and duration of the lightexposure. Brandenburger therefore founded theUV Reline.tec subsidiary in 1997, an engineeringcompany specializing in UVA design.In recent years, UV Reline.tec developed the UVlight sources further that ensure a safe an reliablecuring process. It is important that the UV lampsused operate at an as steady as possible radiationintensity in the wavelength range of 360 to 420nm during the service life. It also needs to beensured that the UV lamps are optimally placedin the liner during the curing process so that theliner is evenly lit even with varying channeldiameters and line profiles.in cm, measuring of the resin reaction temperature,and indication of the travelled path. Upon completionof the rehabilitation the contractor receives acomplete machine-generated documentation ofthe rehabilitation process.ConclusionThe Brandenburger liner system is the enduringfinished product of GFRP compound materials incombination with UV light curing and materialcharacteristics optimally tuned to sewer rehabilitation.The procedure carries the DiBt approval (no. Z-42.3-330) since 2001 and features its own qualityseal "Brandenburger Liner S27.18" with theGüteschutz Kanalbau e.V.the laminated liner even at greater wall thickness.Using the Brandenburger combination curing,rehabilitations can be carried out regardless ofthe necessary wall thickness. The curing speedsare similarly fast even for this procedure.Combination curingIt has been shown that due to the excellent tunedsystem, pure light curing of wall thickness up to10 mm is reliably possible. This covers the majorityof diameters used. Wall thickness greater than that,especially in larger egg-shaped diameters, wouldcause a too slow and therefore uneconomical passingof the liner with the respective UV light sources.For these rehabilitation cases Brandenburger hasdeveloped the so-called "combination curing" andhas successfully applied it since the year 2000.For this the light-curing resins are mixed with asmall amount of heat-curing peroxides. The curingprocess is done by the combination of light andheat curing, but without separate heat applicationin the form of steam or hot water. The exorthermicreaction temperature of 80 to about 130 °C fromthe UV-curing induces the intended heat curingin addition to the light curing and reliably curesFastest curingPacked in UV light-proof, external foil the liner,prefabricated for the construction site requirements,can be stored for long periods.During curing on the construction site the advantagesof the resin-glass-fibre composite developed byBrandenburger come fully to bear with comparativelysignificantly improved curing characteristics.Due to the perfect combination of liner technology,resin system, and UV light technology, curing speedsof up to 150 cm/min are possible.Brandenburger's UV technology is the first thatprovides optimum control over the curing process.The entire process is controlled electronically,monitored, and documented. The most importantparameters are the recording of the ignition times,the number of lit lamps, start and end of the curing,inner air pressure in the liner in mbar, curing speedCombination curing diagram