When it comes to dispensing, conveying and mixing paints and coatings, precision is key. The ingredients must be precise to the gram and must be suspended at defined speeds in order to counteract even minor tendencies to separate. Füll Systembau GmbH achieves this by using the explosion-protected LZB air motor from Atlas Copco Tools.
"I know that there is no all-purpose solution, but we are always looking for the safest and most efficient and durable solution for our customers." Sebastian Noll is quite uncompromising when he explains the philosophy that Füll Systembau GmbH in Idstein follows when it makes components and turnkey systems: "We and around 30 colleagues develop solutions of all kinds here on-site for anything liquid that needs to be dispensed and/or mixed", says the chemical engineer responsible for sales, who specializes in dispensing and mixing technology. These solutions range from comparatively simple barrel, IBC and tripod agitators to customized dispensing plants, as well as the construction of highly complex storage tanks overseas in accordance with European safety standards — and that is in addition to all project planning and engineering services. A gravimetric dispensing plant is currently being built in the production hall and will later be used by a customer for coating large metal parts. A paint that meets the customer's exact order requirements in terms of colour tone is created by adding the ingredients in a documented process with milligram precision, from the base coat storage area to where the paint is applied to the sheet metal.
"In these cases, users talk of 'neck tie colours', the quality of which is guaranteed thanks in no small part to the pneumatic drives from Atlas Copco Tools", explains Sebastian Noll.
Mixing systems with integrated explosion protection
Atlas Copco's air motors are ATEX certified
Füll prefers to use pneumatic drives from the LZB series for mixing the coatings in its plants. Unlike conventional electric motors, they are ATEX-certified. "Around 80 percent of our storage tanks and agitators are used in potentially explosive working environments, where there may be highly flammable solvent vapour, for example. With these pneumatic motors, we are on the safe side". The higher investment costs for electric motors when they are operated in potentially explosive environments—plus electrical installation—mean there are good reasons to choose pneumatic motors. "The small LZB motors are practically cooled from the inside by the exhaust air, so we do not need an additional bulky housing". The drives labelled by Atlas Copco Tools according to explosion protection class Ex II 2GD c T6 IIC T85°C are provided with planetary gears and have been equipped for use in agitators and mixing plants with a reinforced shaft bearing. They are also equipped with oilfree vanes to enable operation with unlubricated compressed air.
PWIS freedom as an additional advantage
"Oil-free operation is an important aspect for us, as any particles of lubricant in the exhaust air can reduce the quality of any type of mixture. Particularly in the automotive industry and when dealing with industrial coatings, paintwetting impairment substances (PWIS) must be avoided, as they cause faults in the coating or crater formation in the surfaces and reduce the durability and robustness of the coating".
In Noll's experience, the LZB motors are particularly suitable for the user-friendly systems at Füll due to their high torque, comparatively low air requirements and simple regulation via the volume flow and working pressure. As the technology is reliable and easy to use, he says that the operating personnel can benefit from everything the motors can offer after a short training period. And as a motor with low rated speed and a higher torque at consistently slow agitation needs to apply much less force and still provides excellent mixing results, Noll adds that Füll often manages with the 380-W pneumatic motors from the LZB-33 series, which are much more compact and energy-saving than the previous larger drives.
"We can agitate acids, alkalis and explosive liquids safely and reliably with the ATEX-certified LZB motors and keep the starting materials homogeneously mixed until the dispensing stage"
Sebastian Noll , Chemical engineer
Simple handling and minimized energy requirements
“By using these drives and through the customer-specific design of our agitators, we reduce their energy consumption by up to 60 percent”, says the very satisfied chemical engineer. In simple terms, this means a maximum consumption of only 8.1 l of compressed air per second in an uncompressed state compared to about 25 l/s for a 1000-W power unit that would otherwise conventionally be used. For a paint dispensing plant, which in some instances may have 24 or even more agitators, this means a significant reduction in operating costs for Füll's customers. Despite the extremely small dimensions, Atlas Copco Tools specifies torque values of 6.0 to 20.9 Nm and rated speeds of 611 to 171 RPM for the LZB-33 models, which are available in four gear designs as standard. The Idstein-based company was initially sceptical, admits Noll in retrospect; the motors seemed much more delicate than their previous models. "But these concerns were unfounded. In terms of durability, the new LZB-33 models are just as stable. We have now installed several dozen and successfully used them in mixing and agitating. The low weight offers additional potential for new applications and savings", emphasizes Sebastian Noll.
