Microfluidics: pressure-driven flow

Pressure-driven flow is a means of driving liquid flow by applying gas pressure (or vacuum) to a sealed reservoir. A pressure and/or flow sensor is used to close the control loop, enabling high-precision control of the liquid flow. This approach has a number of advantages over conventional microfluidic drive systems / pumps, including rapid response time, stable flow control and the ability to support a wide range of flow rates.

In addition, because the pump (or pressure source) does not contact the liquid directly, cross-contamination between liquids is avoided. This separation supports the reusable-consumable model widely adopted across diagnostics, with the pump located in a reusable part of the system (i.e. instrument) and the liquid path in a consumable (i.e. cartridge). With its pulsation-free output, high-precision control and compact form factor, Disc Pump is an ideal miniaturised pressure source for many microfluidic applications.

Download our Microfluidics application note pdf1.39 MB
Download our Point of Care case study pdf1.7 MB

Examples of microfluidics processes controlled by Disc Pump, including homogeneous droplet generation, stop-start and reversible flow control, and side-by-side laminar flow of two fluids.

Learn how to build a microfluidics driver with the Disc Pump Evaluation Kit
and off the shelf components - visit our application page to learn more.

Disc Pump Benefits

Create compact microfuidic systems
Disc Pump is weighs only 5g (< 1/5 oz) and has a volume of just 7 cm3 (< 0.5 in3), supporting the next generation of miniaturised systems.

Pulsation-free flow
Disc Pump produces negligible pulsation, thereby avoiding the oscillatory liquid flow profile often seen with conventional pumps (e.g. diaphragm, peristaltic, etc).

Fast response time
Pressure-driven flow / pressure-controlled systems can react to set point changes in a matter of seconds - much faster than many conventional technologies (see section "Disc Pump vs. Syringe Pump")

Flow rate stability
Disc Pump is precisely controllable, offering excellent regulation of gas pressure / vacuum, resulting in unrivalled liquid flow stability.

Flow rate range
Unlike conventional pumps, Disc Pump has no stall speed, offering a near-infinite turn-down ratio. This makes it possible to deliver flow rates from nl/min to ml/min range.

Versatile function
In combination with valving, Disc Pump systems can be used for a wide range of functions, including aspiration and dispense, sampling, air injection, recirculation and droplet generation.

Pressure and flow control
Disc Pump systems can be integrated with pressure and flow rate sensors, enabling the changing resistance of the fluidic circuit to be considered and the desired pressure / flow profiles maintained.

Miniaturised pressure-driven flow system and schematic

Disc Pump vs. Syringe Pump

Performance of two flow control systems: pressure-driven flow enabled by Disc Pump technology, and a syringe pump. The Disc Pump solution reaches the target flow rate quickly and holds a stable flow rate once at the set point.

The TTP Ventus pump was used to develop innovative reagent delivery systems for microfluidic point-of-care diagnostic devices. The pump’s precision and ultra-controllability offers bubble-free and pulsation free reagent delivery into microfluidic devices and the size makes them the best solution for fluid handling in portable infectious disease diagnostic devices.

Prof. W Balachandran, Research Professor, Brunel University, London