Five benefits of pressure-controlled liquid handling–More precision in lab automation

There are different systems available for liquid handling in laboratory automation. Festo favors pressure-controlled dosing systems for liquids because they offer a wide range of impressive benefits.

Simplicity
Pressure-controlled dosing systems are mechanically simple and require only a small number of components. A pressure regulator, together with a safety valve, pressurizes the tank containing the liquid. The pressure then pushes the liquid through the tubing and the solenoid valve. Next, the nozzle releases the liquid into the vial via a needle tip with a specific opening. Thanks to an easily integrated pressure vacuum generator, it can be operated anywhere, even in laboratories without a central compressed air supply. The system has few moving parts and is easy to clean, maintain, and parameterize. The pressure is set depending on the medium, and the opening time of the valve can be adjusted for the required volume. The basic design is always the same, but different valves can be used depending on the liquid. Media-separated liquid valves, which must be resistant to chemicals when dealing with aggressive media, take care of dispensing, while gas valves are used for pipetting. Aspiration is carried out via a vacuum. Disposable pipette tips prevent contamination when using different liquids. A graphical user interface (GUI) is used as the operator environment.

Precision
Handling minute volumes of liquids is a hugely important step for a large number of processes in laboratory automation. With pressure-controlled dosing systems, volumes from 1L can be dispensed precisely and reliably with a coefficient of variation of <1 percent (depending on liquid volume and ambient conditions). The speed of the liquid can be uniquely controlled via the pressure, and independently of the dispensing, aspirating, and pipetting functions. Users can precisely adjust the system for optimal flow and precision, so a clean drop break-off can be achieved for reproducible accuracy. Solutions with sensitive liquids, such as suspensions can be handled more gently, using lower pressures. In addition, there are many different options for monitoring the process.

Flexibility
Pressure-controlled dosing systems are open and flexible. Many parameters can be changed and individually adjusted, enabling a wide range of different liquids to be precisely dispensed. The systems can also be individually extended or adapted to specific needs.

Scalability
Since many laboratory processes require liquids to be handled precisely, automation leads to significant productivity gains and improved process reproducibility. One of the biggest benefits of pressure-controlled dosing systems is their scalability. For example, individual dispense heads can be combined by mounting them on a rail with a freely selectable grid. All dispense heads can be controlled independently to dispense different liquids simultaneously, or to set different volumes.

Productivity
To increase productivity, the dispense head can be easily integrated into a planar surface gantry. This subsystem enables kinematic movements and liquid handling in a compact workspace, for example, for preparing samples or adding liquids to microwell plates. Pressure-controlled dosing systems enable a high throughput. The high flow rates and constant flow pressure optimize performance, compared to other systems.

Festo offers a comprehensive portfolio of products for pressure-controlled dosing systems that can be easily scaled and combined to best meet your individual requirements in terms of precision, flexibility, or throughput.