Rotary valve carryover and dead volumes

What is the internal volume in microfluidics?

The internal volume is the total volume inside the microfluidic setup flow pathway from entrance to exit. It corresponds to the volume of liquid in the tubings, the microfluidic chip, and also in the microfluidic valve.

What is the dead volume in microfluidics?

It is the volume of liquid that is “stuck” in the system (dead end), which is not cleanly swept and relies on diffusion to clear out.

What is the carryover volume in microfluidics?

It is the volume of liquid that will be mixed with the next liquid, it is not stuck, but it will be swept next time a liquid passes

Distribution valve working principle

Switch valve principle of working

In Advanced Microfluidics, the valve carryover volume is the addition between the volume present in the plug and the volume from plug to port.

What are we doing?

Our rotary valves have no dead volumes, whatever the geometry. They do however have carryover volumes.
Our distribution and switch series are illustrated above. For the on/off series, it makes no sense to talk about carryover volume, as it always the same liquid that is connected. If you change the connected liquid, the whole volume inside the valve will need to be flushed.