Sliplining

A liner is a fiber composite material, which is used for renovation of underground non- grave, pressure drainage and sewerage networks ( sewerage ). The method is referred to as pipe lining. Its main components are thermoset resins that form a matrix by a chemical reaction, as well as textile materials such as glass fibers which have a function of reinforcing and non-woven fabrics are used as the pure form of the carrier resin matrix. Through selective incorporation of so-called aggregates can achieve an increase in the mechanical strengths in certain areas.

Resin types

The most common liner systems based on unsaturated polyester resins (UP resins ) of group 3 according to DIN 18820-1 Table 1 and type 1140 according to DIN 16946-2. The distinctive smell of styrene is used as an infallible indicator of their use. In second place are currently the epoxy (EP ) resins of the type according to DIN 1040-0 16946-2. In addition, the vinyl ester resins of the type 1310 also silicate resins or for special applications according to DIN 16946-2 in use. Basically have all resin systems currently approved by DIBt in Berlin, which are used in CIPP, a higher quality than for example in the yacht building.

According to DIN EN ISO 11296-4 (since 07 /2011 replaces DIN EN 13566-4 ) in section 5.1, there is a liner made ​​of a resin matrix and a carrier fiber with optional use of reinforcing fibers and films that are partially reversible ( inner foil ) and following be removed at the restoration. Some systems leave the inner films after completion of the cure schedule in the attitude, without which they are part of the system. For some, based mainly on synthetic fibers systems, the inner film in the DIBt was incorporated as an integral part. The inner film has to meet the requirements of a specified DIBt test program. Liner must have, according to the DIN EN ISO 11296-4, a minimum thickness of 3.0 mm. Thinner systems are not to be called liner.

Liner can be used as a static load-bearing tube in tube. For this, the system must meet the requirements of the ATV leaflet 127-2 and are measured statically. According DIBt the material has a ring stiffness of minutes in this case. 5.000 N / m have. For the static design, the material has defined, achieve mechanical properties are to be determined by the test or as part of a DIBt approval. For use on private land the DIBt approval is mandatory. As part of the DIBt the material has a series of aptitude tests ( test program ) through, in which the specific properties of the starting materials and the resultant composite material determined and subsequently committed. This is done by accredited and recognized it as a certification body by DIBt inspection. Furthermore, the manufacturer must define and outline the necessary for the installation process technology and the needed equipment.

Curing

The process technology for curing the liner is divided at the moment in four main groups:

In the inversion of the liner is through folding of the inner to the outer surface using water or air pressure brought to the be rehabilitated - similar to put on a sock from left to right. These must be agreed by the water pressure on the local and system conditions, depending on the attitude Sohltiefe above the starting chute a tower be built. In the inversion using compressed air, the liner is placed over a drum in the attitude. The liner is to completely rolled up in a pressure-tight drum and then inversed using compressed air.

Basically, most of the systems shall be supported in a position below the ambient temperature. However, higher reaction conversions are achieved when the formation of the matrix resin when the reaction of the resins is initiated or promoted by temperature. This can be done by the addition of energy in the form of heat. It currently has two variants in the foreground, the warm water curing and steam curing.

Increasing popularity is based on the UV-sensitive photoinitiators systems enjoy. These systems start the reaction by the use of so-called chemical radicals in transition. Here are destroyed by initiation as a result of UV irradiation radicals and the reaction possible. The UV - radiation must be balanced precisely on the resin system.

In all cases, an exothermic reaction is initiated which leads to the curing of the material. It is used for hot water method the surrounding water as a moderator of the reaction, because the heat produced during the reaction is absorbed by the water and prevents uncontrolled overheating. In the UV-initiated reaction of the curing process on temperature sensors on the lamp train is controlled. The temperatures are transmitted to the operator in the control booth. This can then correct the speed of the UV lamp turn. Dampfhärtungsverfahren the reaction is controlled by controlling the steam temperature. The necessary temperature sensors are seated between the laminate and the old pipe attitude. It is important that the sensors are arranged in the bottom area. Since by means of steam and condensate is formed in the hardening, which takes place on the base and must be dissipated, the reaction can be affected in this part of the laminate.

Impregnation

The production of the different systems in the factory and the local impregnation.

Factory impregnation

The factory production of the systems the hoses according to the customer in a pre-fabricated (diameter, wall thickness and length) and comes with resin impregnated to the site. Care must be taken depending on the system that the impregnated tube is protected either before or heat from sunlight. Heat-sensitive systems are supplied iced usually, UV systems are usually in a wooden box. All approved by DIBt systems have a specific, defined installation temperature range is observed. Evident are the DIBt approved systems at the same on the crate clearly must be visible Ü mark. This Ü mark guarantees compliance with the laid down by DIBt material components. On the U-mark is a registration number that always begins with Z- 42.3- XXX. The XXX is a system-related three-digit number. In addition, within the Ü-symbol is the recognized by DIBt, independent certification and inspection body. Only monitored products meet the requirements of the DIBt 's and guarantee the customer the use of process-specific material components and compliance with the required qualities.

Local impregnation

Impregnation of the hose at the local of the impregnation takes place in a mobile mixing plant. This consists of a conveyor belt, the tanks for the components and a static mixer, which must be matched to the resin mixture. It is also advisable if the tanks can be conditioned to comply with the processing temperatures. By applying a vacuum, the air is drawn out of the hose on the one hand, on the other hand, the resin mixture is dispersed in the carrier fiber. Since the fiber is sealed by a working film, which was laminated on one side, a negative pressure can be established. This film forms at the inversion systems later inside the new pipe after rehabilitation. In general, only synthetic fiber liners are currently soaked locally. Fiberglass liners are made ​​at the moment only the factory. This also relates to liner; Short liners that are used in construction, be made with glass fibers locally. Again, a conformity mark must find on the packaging or package insert with the appropriate authorization number. Non- labeled products are not subject to monitoring.

In order to ensure sufficient reaction conversion, curing must occur under specially defined conditions. This concerns, for example, the warming-up phase in which the material is preheated, the curing phase is formed in the matrix and the cooling can be reduced in the stress in the material. Uncontrolled curing, which differs from the system-specific parameters, usually leads to unsatisfactory results in terms of mechanical strength, which provides information on the Aushärtgrad of the material.

Quality assurance

As part of the renovation of the public sewer network specially prepared in the wells of the plastic samples for testing are sent to a laboratory for quality assurance. In general, this mechanical short-term values ​​such as flexural strength and modulus of elasticity by determining the wall thickness according to DIN EN ISO 178 / ISO 11296-4 are determined and compared with the requirements of the DIBt approval or static calculation ( aptitude test ). In addition, the water tightness of the laminate is determined in a 1610 derived from the DIN EN method.

The systems used for the rehabilitation of land drainage lines can largely also be checked using the thermal analysis on their quality. The method used for this purpose coming shortens off with the letters DSC analysis. For quality assurance, there are specially designed for this area accredited testing laboratories.

The liner is a quality product that is constantly evolving. Important for successful rehabilitation are adhering to the standards, technical regulations and process technologies of the systems by trained staff, from the planning to the execution to quality assurance.