Our Senior Applications Engineer Chris Ringer, delves into a recent Wind Turbine Construction project we were involved in. Looking at how we overcame the design challenge and application.
Direct Infusion Technology is a powerful step forward in improving composites processing techniques used within the Wind Turbine Energy sector. It is applicable to infused parts from less than one square metre up to the largest items so far infused at 530 square metres (>6000Kg of resin). Development of this highly effective technique continues and is fundamental in the construction of wind turbine blades.
A major company specialising in composites mixing, spent three years developing a highly automated commercial solution. This was for the infusion of a structural composite components. The technology was developed initially for the marine sector but has now been successfully transferred into production in the wind energy sector.
The company spent several years refining the pumping and flow metering systems, along with the control methodologies. This enabled materials with varying viscosities, temperatures and flow rates to be accurately controlled during the infusion process.
The successful implementation (in the marine and wind energy sectors) of this technology in a large scale production has cemented the company’s position as a market leader in the sector.
The applications are wide ranging, with flows from 15 ml/min to 22 lpm and viscosities from 12 to 2500 cp on peroxide catalyst and epoxy/polyester resin. The operating pressure is typically 50 bar at 80 Deg C.
Metering was required to be accurate and reliable but take up minimal space. This was because the machines developed for the injection are portable, and typically the size of a two-drawer filing cabinet.
For the lower flows and viscosities, the ZHM series Gear Meters were selected. This decision was based on the flow meter’s stainless construction with tungsten carbide sleeve bearings for reliability. For the higher flow rates and viscosities, the SRZ Helical Screw Meters were chosen. These flow meters are also with stainless construction and tungsten carbide sleeve bearing. However, they offer suitable pressure drops considering the high viscosity.
Along with frequency pick-ups, this provides an accurate measure of the components for dispensing the required mix. A PLC based control system contains several recipes which can be chosen, depending on the amount of resin required and the total flow monitored via the flow meters.
The benefits of utilising this process are significant in terms of health & safety, reduced material usage, improved product quality and simplified operation. Waste material on a typical 200-300kg infusion is less than 0.5kg, thereby improving both quality and cost of materials.
Litre Meter is the UK distributor for KEM Flow Meters. We are leading consultants in two-part mixing using flowmeters so contact our team to day for a free consultation on your application needs.
Author: Chris Ringer, Senior Applications Engineer