Institute of High Performance Computing

Khin Yong Lam

Diao Xu

Teng Yong Ng

Lun Sheng Pan

Boo Cheong Khoo

Tieying Jiang

A valveless micropump includes a hollow pump chamber having a driving element coupled thereto, an inlet channel coupled to the hollow pump chamber, and an outlet channel coupled to the hollow pump chamber. The inlet channel, the hollow pump chamber, and the outlet channel define a fluid flow path through the inlet channel, the hollow pump chamber, and the outlet channel. At least one direction-sensitive element disposed in the flow path within one of the inlet and outlet channels and comprising a direction-sensitive element, is installed at an angle which produces a drag ratio greater than unity on fluid in the flow path. The driving element may comprise an electrostatic/piezoelectric member. Various embodiments of the valveless pump include one or more of the airfoil elements mounted in one, the other or both of the inlet and outlet channels, including embodiments in which one or more cascades of the airfoil elements are mounted in the inlet channel and the outlet channel.

Valveless micropump

An electrostatically operated, normally closed micromachined flow-through microvalve device comprises a stationary valve plate layer and a movable valve plate layer, the latter including an electrode plate such that it is deflectable by electrostatic forces under an applied voltage, and having a plurality of movable valve elements, each valve element moving with a degree of independence from the remaining valve elements. Application of a voltage results in deflection of the movable valve elements, the order of deflection depending on the relative magnitude of the electrostatic force experienced by the respective associated portion of the movable valve plate layer. This can be prescribed by the geometry of the device, and a preferred example provides a different separation between different portions of the movable valve plate layer and a further electrode plate in a device base plate layer.

Microvalve devices

A micro-dimensional sensor measures the shear force, both in magnitude and direction, at the surface of a solid boundary as a fluid flows over that boundary. The sensor is a micro-mechanical capacitor-transducer system that includes a micro-dimensioned floating upper plate above a fixed lower plate supported on a substrate. The floating upper plate is mounted and held over the substrate by a number of zig-zap form supporting arms. The flow passing over the upper plate displaces the upper plate in a downstream direction, which results in a measurable change of the capacitance in the capacitor-transducer system. The direction and magnitude of the shear forces can then be obtained from the measured capacitance through specially designed circuitry.

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Singapore, Singapore

Khin Yong Lam