3 Fluidic Control Methods - Disc Pump Demos

By Stuart Hatfield

LEE Ventus works with a wide range of customers who use Disc Pump as an air pressure source for fluid handling applications.

As we discussed in the talk 'Controlling fluid volume, position and flow rate with PDF systems' at the LEE Ventus Fluidics Symposium in November 2021, the compact form factor, high level of pneumatic control and rapid response speed make the pump an excellent choice for fluid handling systems. In this blog post, we look at how—in combination with a small number of off-the-shelf items—the Disc Pump Evaluation Kit can easily be configured to provide a range of fluid control regimes.

1. Flow Control

High-precision liquid flow control is critical in many workflows, for example where it has a significant impact on reaction kinetics, detection rate, hydrodynamic processes (e.g. droplet generation) and so on.

For certain applications, the ability to create controlled oscillatory flow is also valuable. For example, Organ on a Chip systems often strive to mimick physiological processes, such as pulsatile blood flow or the cyclic stress that lung tissue undergoes during the breathing cycle.

The Disc Pump Evaluation Kit can be connected directly to a liquid flow sensor (in this case, a Sensirion liquid flow sensor) to allow closed-loop flow rate control from µL/min to ml/min, as outlined in Schematic A below. The video shows a demonstration of the liquid flow rate achieved when applying an oscillatory power profile when using Disc Pump, as well as closed-loop control of an oscillatory liquid flow profile at different control loop parameters.

Schematic A -

Demonstrates a Fluid Flow Control system using the Disc Pump Evaluation Kit, including a Sensirion Liquid Flow Sensor. "SDC" is a series configuration Disc Pump (e.g. XP-S2-028 or BL-S2-030)

2. Aspirate / Dispense

The pump can be operated with a sealed volume and a pressure sensor to create a compact, low cost air displacement pipette system for aspiration/dispense and dosing applications.

The video shows some early testing we carried out using an Evaluation Kit and a few simple pneumatic components, as outlined on in Schematic B below.

As shown in the video, aspiration and dispense speed can be adjusted by varying the pump drive power, providing a high degree of control. We looked at this this topic in more detail in our previous blog post Pipetting with Disc Pump - Key Learnings.

Schematic B

Demonstrates a closed-loop system with the Disc Pump Evaluation Kit and a sealed volume and pressure sensor. "PDC" is a parallel configuration Disc Pump (e.g. XP-P2-029 or BL-P2-031)

3. Move to Point

Controlling the position of fluid moving through a system with precision and repeatability is a necessity in many fluidic systems.

In this third demonstration, the rapid response of the pump is illustrated by controlling the position of a slug of fluid in a microfluidic chip. In this video we use a vision system to determine when to stop and start the fluid, and a simple flow reversal circuit that allows a single pump to 'push or pull' the fluid between points C1 & C4. At points C2 and C3 the pump power is reduced to achieve a ‘slow approach’ to avoid overshoot.

This is achieved using the Disc Pump Evaluation kit with a small number of off-the-shelf components, outlined in Schematic C below.

Schematic C

Demonstrates a reversible airflow system with the Disc Pump Evaluation Kit and some off-the-shelf components. "SDC" is a series configuraiton Disc Pump (e.g. XP-S2-028 or BL-S2-030)

All three demonstrations were put together with the Disc Pump Evaluation kit with a small number of off-the-shelf components. If you are looking for further information on how to integrate these designs in your own systems you can refer to the talk 'Controlling fluid volume, position and flow rate with PDF systems' from the LEE Ventus Fluidics Symposium in November 2021, or contact us to discuss your requirements. Alternatively, if you are looking to test and explore the Disc Pump technology you can find out more about our Evaluation Kit here.

CATEGORIES   Life Sciences 

TAGS   Fluid Control  Microfluidics  Research & Development 

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