The technology embedded in the WaterLight UV LED system allows contractors to cure impregnated liner at a speed that varies from 0.4 m/min to 1.8 m/min, reducing the average time at the job site and increasing the average number of jobs per day. With shot lengths of 7-8 m, WaterLight UV LED can be up to 6 times faster than traditional curing technologies. Fast UV LED curing enhances productivity.

Though the system is smart and selects the optimal curing speed, the larger the pipe section to cure, the slower the curing speed. Some physics are involved in this variation of speed: the larger the diameter and the wider the surface of liner to be cured, the lower the energy (power) density delivered to the internal surface of the pipe. Water absorption of UV radiation is not significant and hence does not affect the final performance of the system.

A high-power LED array irradiates the impregnated liner, exiting some specific components that initiate an exothermic reaction curing the entire thickness of the carrier resin. Those components have been specifically designed to be sensitive to ultraviolet light at a wavelength of 400 nm. The radiation spectrum of the solid-state components ensures most of the energy is efficiently used to cure the liner. The LED components integrated in the WaterLight UV LED system are lead-free and comply with RoHS legislation.

WaterLight UV LED features a multi-head design to interconnect up to 3 curing heads, allowing the unit to operate with curing diameters up to DN300 and optimizing speed. Each curing head brings 600 W of UV power to the curing process, so WaterLight UV LED radiate up to 1.200 W (double head) and 1.800 W (tripe head configuration). The WaterLight UV LED control unit is capable of driving different cable reels with the different configurations, ensuring the total control of the curing process and optimizing speeds. The last curing head includes, in addition to the LED arrays, a CCD camera to supervise the rehabilitation process.

WaterLight UV LED is designed to cure the liner in the presence of cold water. Contractor might use this water to invert the liner and later to cool the curing head during the process. Water around the head provides efficient passive cooling of the heat produced by the LED modules. Hence, there is no air flow crossing the body of the curing head, avoiding the need for a compressor for this purpose on site. Water is an excellent fluid to ensure proper heat dissipation, even if this water is static. The great mass of this medium conductively exchanges energy with the dissipating plates of the curing head, with virtually no limitation of power and number of heads.

First, the liner is impregnated using the traditional tools found in this industry: impregnation tables, either electrical or manual. Then, the liner is placed in the host pipe using water column or an air-pressurized inversion drum. The use of a pre-liner is recommended. And finally, keep the water inside the pipe and start the curing process. The thermal properties of water would do the job of cooling the curing head.

It is also possible to work with open-end. In situations where the second manhole is not accessible, the rehabilitation can be done from one end of the pipe, by using a dedicated transparent hose. Being transparent is essential so that the UV radiation is not blocked by the hose.

SEWERTRONICS™ resin and liner system consists of a synthetic polyester felt carrier, impregnated with styrene-free vinyl ester resin. The liner is coated with PU, giving the material the necessary flexibility for smooth and easy-to-use installation. At the same time, PU polymer offers a good degree of long-wave UV light transmission.

Liner can be impregnated both at the job site or at the customer‘s impregnation facility. In both cases traditional impregnation tables can be used for this purpose. The styrene-free vinyl ester resin is supplied in one component, so there is no need to mix resin and hardener, avoiding additional work and dosing risks. The chemistry of the resin includes a special component, a photoinitiator sensitive to long-wave ultraviolet light (400 nm).

SEWERTRONIC offers impregnation services at the customer’s request.

The curing head integrates a CCD sensor with a large aperture lens that in combination with a field of view of 170º and a 3000-mW LED ring delivers a bright and sharp image. This camera provides a support to the curing procedure and is not designed to substitute a CCTV inspection system.

As an accessory, the system also includes a Y-connector. This element is connected to the inversion drum by a Storz coupling, allowing introduction of the LED curing head inside the pressurized pipe. Plastic seals make sure no air pressure is released. SpeedyLight+ is designed to work without this element not being indispensable to conduct UV LED curing.

The system is supplied with two different cable-hose reels. Standard length is 50 m but it is possible to order units with a length of 100 m. The shorter the installation length, the more efficient the WaterLight UV LED system becomes. The reason for this lies in the fact that hot water and steam curing methods need the same curing time for any given length - a 7 m installation requires 2-4 h and the same applies to 50 m. With UV LED curing technology, curing time is proportional to the curing speed, which typically varies from 0.3 to 1.8 m/min.