Australian engineers have used special metals to construct pumps with no moving parts. 

Metals that are liquid at room temperature, such as gallium, can be controlled by an applied voltage to a new type of pump that has no moving parts.

The development could radically improve performance, and reduce maintenance costs in the chemical and pharmaceutical industries. 

Traditional mechanical pumps and moving parts could potentially be replaced by ‘soft’ components that cannot fail in the life of the machine. A video demonstration is accessible here.

Flow reactors are being increasingly adopted in pharmaceutical and chemical industries, as they allow fast reactions, offer safe control, and enable easy scaling-up opportunities. 

These industries are becoming more inclined to implement flow reactors for increasing product quality and yield of chemical and biochemical reactions.

However, one of the most important technological issues is with the core components of such reactors, which generally use moving parts, which can be fouled, blocked, and broken via precipitation of materials, hence compromising the productivity and longevity of the systems.

One possibility to overcome such drawbacks, while keeping the functionalities of the continuous flow reactor, is replacing the traditional mechanical pumps and moving parts with soft and never-failing components.

Liquid metals exhibit the potential to design continuous flow reactors as their low melting point, non-toxicity, controllable shape, and reactive surface offer what efficient and durable flow reactors require.

Interestingly, the flow formed around the liquid metal reactive core, called Marangoni flow when an external voltage is applied, eliminates the need for moving parts and relies instead on surface tension to do the pumping of the flow.

Additionally, the active surface of the liquid metal facilitates chemical reactions.

Thus, the liquid metal simplifies the continuous flow reactor design, and it plays two critical roles in the system for material synthesis and also for mass transport.

The researchers from UNSW, and their collaborators from Queensland University of Technology (QUT), Australia, and University of California, Los Angles (UCLA), USA, have demonstrated a continuous flow reactor enabled by liquid metal droplets in their cores.

The team introduced three different model examples into the reactor to produce three popular functional materials:

  • manganese oxide, which is widely utilised for the synthesis of soft ferrites

  • graphene, which is used in many applications such as those in water purification and energy storage/conversion

  • molybdenum sulphide, which is known for its new applications in microelectronics

The system showed versatile capabilities for generating materials with tuneable system performance and controlled material quality.

“The liquid metal can be easily integrated into a fluidic channel for constructing the continuous flow reactor,” said Mr Jialuo Han, the first author of the work. 

He added “The liquid metal itself can spontaneously produce materials on the surface and the material is repelled away from its surface with the application of an external voltage.”

“This proof-of-concept continuous flow reactor is enabled by a single droplet of liquid metal, which can be extended for synthesizing many different valuable materials with high-quality control,” said Dr Mohannad Mayyas, a corresponding author of the study. 

“It has no mechanical parts and can in principle be readily scaled up for future commercialisation.”

More details are accessible here.