Developing the island mentality

Parker Pneumatic has developed a miniaturised pneumatic valve system called Moduflex, which it hopes will revolutionise the design of electro-pneumatic control and automation systems

Electro-pneumatic automation techniques have progressed through the use of PLCs, fieldbuses, cylinder integrated sensors and modular pneumatic valve islands. Pneumatic valves are now designed into compact islands that are easily configured for each installation requirement.

But currently, most valve island systems are factory-produced. The total modularity of the Moduflex system is designed to enable users to build customised valve islands for themselves. This adds to flexibility, with post-assembly island modifications being easy: valves can be added and removed, functions changed, tubing sizes and piloting changed, all in minutes. However, for those users who require it, fully assembled valve islands can also be supplied in the traditional manner.

Two sizes of miniature high flow electro-pneumatic valves, three series (standalone valves, compact valve islands with individual electrical connectors and valve islands complete with integrated electrical connection) and four valve functions (4/2 single solenoid, 4/2 double solenoid, double 3/2 NC and double 3/2 NO) combine to enable the Moduflex system to be configured to control virtually any pneumatic application.

Large bore tubing Flow rates allow the operation of cylinders with bore sizes up to 100mm. Size 1 valves for air flows up to 400Nl/min, with 4mm or 6mm OD tubes for pressure supply and exhaust collection, will control the operation of cylinders from 6 to 40mm bore. Size 2 valves, for flows up to 1200Nl/min, take 8mm or 10mm OD tubes and will control cylinders from 40 to 100mm. Working pressure is vacuum to 8bar (120 psi).

Another advantage of the Moduflex system is the facility to incorporate two sizes of valve in the same island, for varying flow requirements. The overall height of the island remains the same. Size 1 units are 25mm wide, Size 2 are 37.5mm wide.

At the heart of the Moduflex valve design is an ingenious application of the well-proven ceramic slide plate technology. It provides for long service life in excess of 100 million cycles and with only around half of the working parts of a traditional unit.

Each individual valve module is available with a choice of push-in pneumatic connections, either straight or elbow, in a range of sizes. For safety and standardisation reasons, most machine builders now use 24VDC. This convergence towards only one voltage leads to a simpler system with a solenoid pilot manual override, which is a multi-function, tamper-proof system for each stage of system commissioning. The low consumption 24VDC electrical solenoids can be supplied with cable plugs for individual wiring or with plug-together integrated electrical connections for multi-wire connection. LED indicators are a standard feature of all solenoids.

With short valve islands up to five solenoid pilots, the individual connector is still preferred. However, for longer islands, integrated electrical connections become more viable. Individual electrical connections are protected against dust and water to IP65 standard, with IP67 protection for integrated connections.

The two wires of each connector cable can be taken directly to the output terminals of a PLC or fieldbus terminal. If all outputs have a single common terminal, it will be necessary to use an intermediate terminal block. On all valve island versions, the pressure and all exhaust flow paths, including pilot exhausts, are common. For standalone versions, push-in exhaust port silencers are available.

Easy add-ons Peripheral control modules, such as dual-flow modules, pressure regulator modules and dual pilot-operated check valve modules can be plugged in directly to the valve island, or installed in-line closer to the cylinder. All Moduflex modules may be DIN rail mounted.

• Parker Pneumatic
  Email b104@industrialnetworking.co.uk
  

Caption: The Moduflex super-compact 4/2 slide valve concept features: a very short stroke (2.5mm) slide and spool arrangement, which implies short response times; a large spool diameter (14mm), which provides higher shift force for totally reliable piloting, even with dry and contaminated air; a lapped ceramic plate and slide arrangement, providing a total seal and long life in excess of 100 million operations