A new line of pneumatic directional-control valves uses piezoelectric technology in poppet and packed-spool valves. Heart of the Piezo 2000 valve from HoerbigerOriga, Glendale Heights, Ill., is a miniature threeway valve that controls flow with two ceramic reeds similar to a bimetallic strip. Applying a voltage changes the length of the reeds and causes them to bend, which opens the valve's pressure orifice. This pilot pressure signal shifts the main valve spool.
Power consumption is negligible with Piezo 2000 valves — 0.003 W at 24 Vdc or 0.77 W at 220 Vac — because there is no solenoid or winding. Valves can be powered by a 9-V battery for more than 4 million cycles, and the ceramic reed has a cycle life in the hundreds of millions. The operating signal can be analog or digital, which allows a variety of controllers to operate the valve. Finally, the piezo pilot generates virtually no heat, which can degrade valve and electrical components.
The valves are available in 3/2, 5/2, and 5/3 configurations with internal or external pilots. They are rated for air pressure to 150 psi with flows to 6,600 lpm.