Flow of ideas

The changing demands of major industries are being met with a range of innovative valve systems. Julia Pierce looks at the benefits of some of them.

World demand for industrial valves is growing. The market earned revenues of more than £13bn in 2007 which, according to analyst Frost & Sullivan, will increase to just under £25bn in 2014.

While much of this is from emerging economies where the need for clean water and changing eating habits requiring increased food processing are driving markets forward, innovation is also taking place closer to home following pressure from legislation.

Festo is launching a number of pneumatics safety products to help manufacturers comply with Machinery Directive 2006/42/EC. Part of this legislation stipulates health and safety requirements for the design and construction of machines.

The company’s MS6-SV soft-start and exhaust valve offers maximum safety in safety-relevant areas through rapid venting in the event of an emergency stop. It serves as a decentralised or centralised unit for supplying machines and systems with compressed air and consists of a self-testing mechatronic system with built-in redundancy, ensuring reliable exhausting even if defects occur within the valve.

To simplify installation, the safety check of the piston rod position is performed directly by the valve during self-test. Exhaust performance amounts to 6,000 litres/min, 1.5 times pressurisation performance. Traditional switch-on and pressure build-up functions have been integrated in the exhaust valve.

Elsewhere, Rexroth recently added a new size to its modular directional valves rated at up to 25 litres/min and for working pressures of up to 310bar. The compact and rugged valves can cope with the harsh working environments inherent in mobile machines. The new size complements Rexroth’s comprehensive range of modular directional valves, which now covers workflows of up to 50 litres/min. Although based on NG4/NG6 technology, the valves avoid sub-plates and can be easily tailored to specific workflow requirements, especially when compared to standard CETOP (European Fluid Power Association) technologies.

As the system is modular it is easy for users to add to units. Individual sections come in different sizes with one common interface that ensures cost-effectiveness, since the engineer can choose the appropriate size per section according to the required flow.

Sections can have integrated load sensing as well as other integrated functions such as check valves, relief valves, counterbalance valves, flow regulators, emergency hand levers and emergency hand pumps, allowing users to build systems to suit their individual needs. Various portings and coil connections are available, while the sectional valves can be connected to Rexroth’s power modules and integrated control blocks with cartridges and other valves to create hybrid systems.

Meanwhile, Durapipe is expanding its VKD valve with the next generation TKD ball valve using its Dual Block technology which prevents accidental loosening of the union nuts.

The three-way TKD ball valve is said to provide superior flexibility by offering end users the ability to redirect flow for easy maintenance and repair of industrial systems. It incorporates the Seat Stop system which sees the ball seat carrier manufactured in two pieces to ensure greater longevity of the seals in severe situations where vibration or thermal expansion occurs.

According to Durapipe, the TKD valve was developed to offer all the high performance benefits of the VKD but with three-way capability. As it is fully interchangeable with the previous TK model, businesses can easily upgrade.

According to James Roper, industrial brand manager at Durapipe UK: ‘The new three-way TKD valve has been specifically designed for use in industrial pipework systems. It is available in a choice of materials including ABS, PVC-U, polypropylene and PVC-C to ensure it can cater for a variety of substances, making it suitable for a wide range of industrial process applications.

‘The valve is perfect for diverting or sampling a flow without ever having to shut it off . Furthermore, the compact design of the valve makes it ideal for installations in crowded environments.’

He added: ‘Its unique, patented Dual Block technology makes it an ideal solution to meet the demands of severe industrial applications, as it prevents the accidental loosening of union nuts which can occur with alternative valves under harsh working conditions, particularly where thermal expansion or vibration occurs.’

The TKD has been designed to allow an actuation device to be easily added to the valve body, which can be fully assembled and tested at the Durapipe in-house valve department. Also, it has a multi-functional handle, that can be equipped with a block to lock the valve in all positions, without increasing the overall valve dimensions.

Finally, Bürkert has refined its 8640 for systems and processes in water treatment, dairies, food and beverage manufacture, pharmaceuticals and biotechnology, cosmetics, chemicals, textile dyeing and drying equipment, transportation and automotive, semiconductor manufacturing, pulp and paper processing.

The manifold system is for large process actuation systems requiring up to 192 valves. The 8640 provides decentralised system expansion via a single fieldbus cable, 32 I/O per module and the facility for different size valves — 10mm, 18mm and 32mm — on the same manifold, to cater for all size and flow performance demands.

Both the electrical and pneumatic interfaces are based on a modular design, and the device is controlled by a unique Bürkert rocker-design pilot valve. This technology offers extremely high life-cycles and the valve performance is not lubrication dependent, delivering long service life even with non-lubricated dry air.

The valves and the manifold modules are made from high quality thermoplastic, and the integrated snap together design makes it easy to customise systems.