Microfabricated Flow Controllers and Pressure Regulators

Efforts are underway to develop microfabricated flow controllers and pressure regulators that contain as few discrete components as feasible and that are cheaper, more robust, and orders of magnitude smaller than are currently commercially available devices that have similar capabilities. The developmental devices are designed to interact with electronic sensing and control circuits that include microprocessors that, in turn, communicate with host computers of digital feedback control systems. An example of the prototype devices constructed thus far is a hybrid device that includes a flow sensor, a valve containing a TiNi-alloy microribbon shape-memory actuator, and a temperature sensor, with wire-bonded leads for connection to electronic circuits. Windows™-based software for interaction between host computers and the microprocessors associated with these devices has been written. Contemplated further development efforts would be devoted to advancing from the concept of a flow controller on a ceramic substrate to that of a flow controller on an assembly of two or more semiconductor chips. In principle, fabrication on a semiconductor chip could be accomplished without need to assemble discrete components.