Classic
Valves
The Festo Classic category contains time-delay valves from the VZA/VZB/VZOA/VZOB series in G 1/4 port size. These four articles are pneumatic timing elements: VZA-3-1/4 and VZOA-3-1/4 are switch-on delay valves (delay on pressure build-up); VZB-3-1/4 and VZOB-3-1/4 are switch-off delay valves (delay on pressure release). All four operate without electrical power, using compressed air as both energy carrier and signal medium.
| Article | Type | Function |
|---|---|---|
| VZA-3-1/4 | Switch-on delay | Output signal appears with a time delay after the P-signal input |
| VZOA-3-1/4 | Switch-on delay | As VZA, alternative housing variant or predecessor type |
| VZB-3-1/4 | Switch-off delay | Output signal is maintained for a time after the P-signal disappears |
| VZOB-3-1/4 | Switch-off delay | As VZB, alternative housing variant or predecessor type |
Pneumatic time-delay valves use an integrated orifice-reservoir system: the orifice and reservoir volume together set the delay time, which is adjustable via a set screw. The G 1/4 port fits standard compressed air lines. The Classic series is compatible with older Festo systems and allows direct replacement without re-routing pipework.
Typical applications: Time-delayed enabling in pneumatic sequence control, start-up delay when pressurising compressed air systems, safety timing elements in presses and clamping fixtures (delay after pressure release), replacement of failed time valves in legacy Classic-series installations, and simple timing functions in all-pneumatic circuits without PLC.
