Directional control valves boost production efficiency
How can OEMs take maximum advantage of improvements in directional control valves when designing automation and piloting equipment? The experts at Asco Numatics argue that it may be helpful to adjust our thinking.
There have been many improvements and refinements in directional control valves in recent years, but getting the most from them means we have to adjust our thinking and reassess these components. Valve manifolds are relatively small subsystems in generally much larger assemblages of automation equipment. But the right valve can open up wider degrees of freedom when designing larger automation elements.
Further, automation specialists may conceptualise pneumatic components as if they were simple electrical on/off devices, but that perspective is limiting in important ways. When you send your signal to activate the valve's solenoid coil, the air inside the valve must be made to change direction. The speed at which it does so, and the amount of air that flows in that new direction, may be substantially affected by quite small changes in the arrangement and construction of the valve internals. These can make significant differences in performance when OEMs design them into machines.
Recent technological refinements mean that the latest-model directional control valves are now available with substantially greater air flow rates through the valve. For example, the 503 series from Asco Numatics can offer up to a 20% higher flow rate per valve size than previous models, achieved by rigorous analysis of air flows and comprehensive refinements of the existing valve's internal design. Ultra-high flow carries significant benefits:
1. Same work, smaller valve - Most users will take advantage of the design freedom that higher flow delivers to accomplish the same performance as with previous models, but in a smaller valve envelope. This is part of an important, ongoing industry trend. A decade ago many industries applied pneumatic valves with measure-ments set at ISO standard widths of 50mm and 38mm. Today, many of these operations are moving to 26mm or 18mm products. Decreasing the envelope size has important ripple effects:
Estimates show that the cost savings for some users can be truly exceptional, and a number of OEMs report that these benefits are amplified when designs are already near a tipping point. Calculations may reveal that the newest valves make the decisive difference. So designers are finally able to realise their plans of downsizing associated equipment, or dropping a level of magnitude (and cost) in power consumption, or reaching a new plateau of total production throughput. These kinds of noticeable improvements can help an OEM gain a clear advantage in the most challenging competitive environment.
2. More work, same size valve - Some users will utilise their new freedom to avoid downsizing directional control valves or other components, instead increasing the amount of work the system can perform, perhaps by raising production levels. Or they may choose simply to increase the total efficiency of the operation. For instance, the newest valves can provide greater speed of component motions for higher cycle rates. Choosing a valve with enhanced technology may let the designer meet goals more efficiently, or set and reach new goals.
Enhanced electronicsAnother advantage of some newer directional control valves is integration with the latest fieldbus modules and electronics technology via the valve manifold. The larger and/or more complex the plant network, the more important this advantage becomes. A good example is the Asco Numatics G3 fieldbus electronics system. This kind of platform lets designers take valve and manifold selection in a whole new direction. Critical advantages include configuration ease, distribution flexibility, and diagnostic capabilities.
When it comes to configuration, we can forget the dreaded DIP switch. New technologies enable configuration of communi-cations protocols, distri-bution options, I/O mapping, and more - all via graphic displays and pushbuttons embedded on each module. Configuration head-aches are relieved, while installation time and commissioning costs go down. To aid distribution, the newest fieldbus nodes integrate both valves and I/O capabilities. In addition, I/O and valve manifold functionality can be distributed around the machine, so designers can optimise its physical layout using only a few basic multifunctional modules.
The module-integrated graphic display can provide clear point-of-use diagnostics with plain-language messaging to identify problems. So you get easy identification of any issues, plus simple, intuitive configuration of new manifolds and other new components on the fieldbus network. This level of status monitoring and feedback helps ensure asset availability.
Look for directional control valve models where the manufacturer has reexamined every aspect of valve design and performance to identify and carry out potential improvements in basic reliability. What's the consequence of inefficiencies within the valve? What specific wear patterns do this produce? How do the seals function, and where do they wear? When and how does any leakage occur, and how can it be eliminated? When a manufacturer addresses these issues, users can benefit from longer time between overhauls, reduced downtime and maintenance costs, and lower total cost of ownership.
Look, too, for valves designed with internal construction flexibility that allows them to be optimised for different applications. Of course, different valve sizes are always offered. Also, your operation may benefit from the flexibility of valves now available in both ISO standard and proprietary interfaces to cover virtually any application.
Accessories such as pressure regulators, flow controls, and more can also be built into the manifold for greater flexibility. These may be enhanced by tools such as Numatics Numasizing software, which optimises the automation system's compressed air flow by precisely calculating proper sizes for pneumatic components, and selecting appropriate pressures. Users say they reap substantial cost returns from resulting air and energy savings.
Even the physical build of these new valves and manifolds helps maximise versatility. Modular plug-and-play components allow easy reconfiguration, even after initial design and assembly. This goes along with external accessibility. Look for manifolds that don't require removal of seven valves in a row to 'get at' the eighth valve. Innovative models come apart wherever needed, eliminating construction difficulties.
Directional control valves have recently been the focus of intense refinement and reengineering efforts. These have produced enhancements including ultra-high flow rates, greatly improved electronics, ensured reliability, and expanded versatility. Forward-thinking OEMs are changing direction to take maximum advantage of these developments, thereby realising significant cost savings and gains in production efficiency.
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