Valves are ubiquitous in all HPLC and UHPLC applications. They act like a switch and can control the flow path of the chromatography system in various ways. Therefore, valves are indispensable for eluent selection, sample injection, column selection, and fractionation as well as any switching task.

KNAUER valves are designed for a wide range of chromatographic and dosing applications. Flexibility is provided by choice of different materials and sizes as well as drivers for various software packages. Valves are driven either manually or automatically through a valve drive.

The Valve Unifier is a smart valve drive/actuator with RFID technology (Radio-frequency identification). It features automatic valve recognition and adjusts torque and switching speed specifically for each valve. Therefore, only one valve drive is needed regardless of the valve from analytical to preparative scale. 

Each valve head is equipped with an RFID tag that stores all relevant data. This data is read wirelessly by the VU 4.1 valve drive and the switching parameters are automatically adjusted.
For example, a 1/8 inch valve with 2 mm bores, due to its size, requires a higher torque than a 1/16 inch valve with 0.3 mm bores.

With older valve actuators, these different requirements were not taken into account, just the number of connections and the mode – e.g. two or multiple positions – could be selected. Therefore, the switching parameters for a 6-way two-position valve were always the same, regardless whether a 1/8 inch or a 1/16 inch valve was mounted. As a result, especially small diameter valves were switched more slowly by the actuator than the valves would have been able to because the actuator torque had to be optimized for the harder-to-switch 1/8 inch valves. Automated valve detection via the RFID tag ensures that switching speed and torque are always optimally adjusted to ensure the best performance of each valve. For example, 1/16 inch systems benefit from a significantly reduced pressure increase during switching.

More advantages of the AZURA valve drive:
- Time savings during setup
- Exclusion of misconfiguration by the user
- GLP data such as number of switching operations are monitored for easier planning of maintenance to minimize wear-related downtime

The valve drive works as stand-alone device thanks to an integrated display but can also be controlled via our supported software. Due to various interfaces and the small footprint the valve drive AZURA VU 4.1 can easily be used to upgrade an existing system.