Advanced valve engineering
3rd Quarter 2015, This Week's Editor's Pick, Pneumatic systems & components
Emerging out of the previous Bosch Pneumatics division of Bosch Rexroth, Aventics has celebrated its first year as a standalone pneumatics company and a leading manufacturer of pneumatic drive and control solutions, components and systems. Sold to Nordic investment firm, Triton Investment and rebranded as Aventics, the company has been able to focus on its core business and invest heavily in R&D, re-establishing itself within the pneumatics industry and defining the next generation of pneumatics.
“Intensive R&D is what sets Aventics apart,” says Tectra Automation’s general manager, Kevin Lombard. Wolf Gerecke, head of product management at Aventics explains that the company called on all known principles of design, materials science and assembly during the development of this advanced valve series. “The modular AV series is based on expert development, engineering, production, service and logistics – all seamlessly intertwined and geared towards the needs of our customers,” he adds.
Smaller, lighter, safer
Features that set the AV 03/05 valve range apart from its competitors are faster switching times, lower weight and smaller size. The valves also meet the latest European safety directives.
These valves have a very high flow rate for their size. By optimising the supply and exhaust channels, developers have reduced flow losses, resulting in a huge flow improvement of 40%. This has allowed them to substantially lower the supply pressure and boost energy efficiency. The AV 03 is rated at 300 l/min and the AV 05 at 700.
Smallest on the market
Pneumatic valves should ideally be situated close to the point of action in handling systems, so their dimensions are crucial to the overall design. Machine designers try to position them as close to the actuators as possible because shorter tubing lengths can reduce the compressed air requirement by up to 20%.
Thanks to a diagonal arrangement of the valve components, the AV valves are extremely compact. The required installation space has been cut by an incredible 45%. The result is a lower pressure drop across the system and optimised performance. Smaller valves also mean smaller main drives, resulting in a lower initial investment and an improved energy footprint.
In addition the weight of the new valves has been halved by using high performance polymers and reducing the number of parts. As a result they are up to 40% lighter.
Another benefit of the AV valves is their adaptability. Changes in valve function can be carried out very quickly. Even the push-in fittings can be modified and exchanged. The connection elements do not affect the dimensions, and with easy application retrofitting the valves are highly flexible. Base plate valves enable fast, easy assembly; up to 64 valves can be added to the board in single increments. Each valve slice is fastened with only one captive screw. For installations at heights of four metres, for example, this is important in order to avoid losing screws.
Section-based shut-off meets machinery directive requirements
Safety is at the heart of the AV range and the safety circuit is an integral part of the control system. It embraces Rexroth’s Safety On Board feature, where safety monitoring and safety control are built into the company’s range of servo drives and servo controls. When a safety system is triggered, it immediately enters safe mode and prevents cylinders or actuators from being activated inadvertently on electronic, pneumatic or electromechanical systems by cutting off air to the components. This prevents accidents from happening.
Safety On Board allows design engineers to combine all pneumatic actuators in a system with the same compressed air supply, exhaust and control, while controlling safety functions separately for safe shutdown in accordance with European machinery directive ISO 13849. This directive requires safe shutdown of defined functions while other areas remain functional, and reduces downtime for manual intervention with the machine.
The power supplies for the actuator and the logics are isolated through the Aventics advanced valve electronic system (AES). Thanks to these independent signal paths, the user can target and shut down the output for the actuator in individual valves while continuing to address the logic via the fieldbus protocol. With galvanic isolation, the AES also fulfils the regulatory requirements for the use of external power supplies and upstream safety relays.
“If South African companies want to compete globally they must offer the same safety standards as are called for overseas. We have local machine manufacturers as clients who compete globally very successfully and these safety features enable them to stay competitive with respect to the latest requirements,” says Lombard.
Advanced electronic system
The decentralised AES fieldbus connection processes analog as well as digital signals and allows for fast assembly and flexible use. It offers interfaces to all standard fieldbus and Ethernet protocols and controls up to 128 coils in one system with up to 64 valves. Additionally it contains an extensive modular system with analog and digital I/O modules. Each AES fieldbus coupler controls up to ten I/O modules. This allows machine manufacturers to incorporate peripherals such as sensors or single valves and cylinder/valve units and reduce cabling.
Major economic challenges in the production environment include the time required for design, installation and commissioning, as well as effective operation. Here the flexibility of the AV system pays off. This optimised interaction of the valves with the AES fieldbus connection and the wide variety of components is a crucial benefit.
For Tectra Automation, key customers are machine builders, especially those that manufacture packaging machines. An example is Marcé Fire Fighting Technology, a Centurion-based company that uses Aventics valve banks on its firefighting trucks to operate the water guns, ladders, valves and cylinders. Marcé’s production planner, Willem Grobler says, “In the firefighting industry failing equipment is unacceptable, therefore we require quality, reliable systems to operate our fire engines. Aventis products cater to this need. Good service, reliable products and global aftermarket service are only a few of the reasons why Marcé has decided to partner with Tectra.”
Pneumatic product manager, Malan Bosman says that Tectra is now accredited by Aventics to assemble the AV range locally following extensive training of the team. “This means we will be able to stock the valves locally so the turnaround time will be very good,” he explains.
He adds that the newly released Aventics RTC range of rodless cylinders has also been very well received, again filling a need in the market for compactness. Tectra is currently tooling up and undergoing intensive training and from September will also be stocking components and barrels, with the facility for local assembly.
Five businesses in one
Tectra has five businesses: linear technology, electric and control systems, assembly technology, pneumatics and vacuum technology. “We don’t just offer pneumatics, we can offer a variety of technologies in the Rexroth range and can offer electromechanical solutions as well,” continues Lombard. “Thirty percent of our business is in automotive-aligned industries. We supply system integrators who build equipment for motor manufacturers, an example being catalytic converter lines for Daimler.”
He adds that one of Tectra’s fortes is the control side. “Using the Rexroth range of PLCs and CNC controllers we can take total ownership of a solution – the customers don’t have to find a control solution from a third party. We can also make recommendations regarding the best possible solution across the whole spectrum, be it a highly controlled electromechanical solution or a relatively low cost pneumatic solution.”
Tectra also stocks a full range of fittings, tubing and valves. Cylinders are manufactured locally so the turnaround time is very short. The company operates in Africa as well and has access to the Hytec African distribution network in Zambia, Mozambique, Zimbabwe, Botswana and Namibia. “We are proud to be part of the Hytec group which gives us 24/7 access to a broad range of expertise,” says Bosman.
Lombard says that another competitive advantage is Tectra Automation’s dedicated pneumatics team. “We will find a pneumatic solution to almost any problem and we have access to a wide range of expertise. We have had situations where competitors tried to solve problems in an application and failed and we came in and rethought the whole thing and were able to do the job. One such example is a vacuum system used to lift bus roof components – 16 metre long panels,” he recalls.
More on the way
This is only the beginning. “While developing the AV series we focused on exploring the limits of valve technology and looked at everything in an entirely new way,” says Theo Paulus, head of pneumatics development at Aventics. “The result of our research has been groundbreaking. Each component is a small masterpiece. We are at the cutting edge of technology with this family and more groundbreaking innovations are already being tested.”
For more information contact Malan Bosman, Tectra Automation, +27(0)11 971 9400, firstname.lastname@example.org, www.hytecgroup.co.za