Flexible miniature pump for a wide range of applications
Fluid control components in medical devices should be quiet, compact and lightweight. The Lee Disc Pump combines all these features. What’s more, its high-precision controllability and fast response time make it suitable for a wide range of applications.
Lee’s Disc Pump is primarily used in the medical technology sector, particularly in portable therapy devices. Wherever maximum patient comfort and/or high-performance fluid control are essential, these miniature pumps are the right choice. As the piezoelectric pump operates using ultrasonic technology, it is vibration-free and inaudible to humans. This enables the development of devices that can be worn directly on the body whilst sleeping or continuously, without unduly disrupting the patient’s daily life. The extremely compact dimensions of 10 mm in height and 30 mm in diameter, as well as the minimal weight of just 5 g, also contribute to this. The piezoelectric operating principle enables flow control with a precision of < 0.1%.
The compact form factor, high control precision and fast response time make the pump an excellent choice for a wide range of fluid control systems. This flexibility is highlighted below by various configurations realised using the Disc Pump Development Kit.
Flow control
High-precision control of fluid flow is of crucial importance in many medical technology processes, for example where it has a significant influence on reaction rates, the detection rate of substances or hydrodynamic processes (e.g. droplet formation).
For certain applications, it is also advantageous to generate a controlled oscillating flow. Organ-on-a-chip systems, for example, often seek to mimic physiological processes, such as pulsating blood flow or the cyclic stress to which lung tissue is subjected during the respiratory cycle.
The Disc Pump Development Kit can be connected directly to a fluid flow sensor to enable flow rate control from µL/min to mL/min, as shown in Diagram A. Such systems are also used in compression therapy, blood pressure monitors, patient simulators and patient monitoring systems.
Dosing systems
The Disc Pump can be operated with a sealed reservoir and a pressure sensor to create a compact and economical pipetting system for aspiration/dispensing and dosing applications. The aspiration and dispensing rates can be adjusted by varying the pump drive power. This enables highly accurate dosing.
In addition to typical pipetting systems, this system design can also be used to implement time-controlled precision dispensing systems, such as those found in medical analysis technology.
Fluid position control
The precise and repeatable control of the position of a liquid moving through a system is essential in many medical fluidic systems. This third configuration allows the position of a drop of liquid to be controlled with maximum precision and minimum response time. Image processing systems, for example, can be used to determine when the liquid needs to be moved. A simple current reversal circuit enables a single disc pump to move the fluid between different points in both flow directions. The pump’s high-precision control also allows for a slower ramp-up at intermediate positions to prevent overshoot beyond the desired target point. These positioning systems are used in microfluidic lab-on-a-chip systems.
All three demonstrations were put together using the Disc Pump Development Kit and a small number of off-the-shelf components. These kits are characterised by their ‘plug-and-play’ nature. With a user-friendly GUI and software, integrated pressure sensors and integrated valve drivers, the kit offers advanced fluidic control and enables the time-efficient creation of test configurations, ranging from microfluidic and liquid-handling systems to medical devices and industrial instruments.
