Suspension-Compatible Elastomer-Glass Micropumps Employing a Linear Topology

We report a simple, high pumping performance, micropump comprising a narrow flow channel with integral flow control structures operated by a single actuator element. Unusually, it does not have a distinct pump chamber. This micropump is termed a ´Linear MTP´ (LMTP) as it exploits the microthrottling principle and single actuator operation of MTP devices we have previously reported. Uncharacteristically for a micropump and in common with all MTPs, the device is compatible with solid phase suspensions. The flow-channel-like, linear pump minimises the development of recirculatory flows that are typically associated with circular pump chambers and in part, determine the frequency response and hence maximum pumping rates of many micropumps. The actuation of linear pumps by flexing, bimorphic, discoidal actuators is possible by virtue of an elastomeric substrate which allows actuator flexure over solid substrate regions whilst to some degree constructively coupling the forces in those regions into active regions. We have modelled, fabricated and evaluated an LMTP that yields a maximum pumping rate of circa 1.15 ml min^-1 and a back pressure of 39 kPa at a drive frequency of 1.8 kHz. Images of 5 mum polystyrene beads flowing within the LMTP confirm minimal recirculatory flow consistent with the LMTP´s increased operating frequencies compared to previous circular pump chamber MTPs.