Ulrich Bonne

TL;DR: In this paper, a flow control device includes a housing with separate main flow and flow control (servo) passages between an inlet port and an exit port, where a flexible membrane forms a partition between the main flow passage and the control chamber.

TL;DR: In this article, an electronic microvalve design and fabrication process for a miniature gas valve is described, where the objective is to minimize the operating voltage of the valve and minimize the force necessary to close the valve.

TL;DR: In this paper, a method and apparatus for determining both the thermal conductivity, k, and specific heat, cp, of a fluid of interest are disclosed. But the method is limited to the case where both a transient change and a substantially steady-state temperature occur in the sensor.

Abstract: A process for fabricating a flow control device which includes a housing with separate main flow and flow control (servo) passages between an inlet port and an exit port. A control chamber in the housing is in fluid communication with the servo passage. A flexible membrane forms a partition between the main flow passage and the control chamber. The servo passage includes a variable servo orifice upstream of the control chamber and a fixed orifice downstream of the chamber. When the servo valve is open to permit passage of fluid into the control chamber, the resultant pressure on the membrane maintains the main valve closed. The main valve opens in response to closing the servo valve. The fixed orifice has a profile sufficiently small to provide for an acceptable leak or continuous fluid flow through the device when the servo valve is open, and further provides for a soft start when the servo valve is closed to open the main valve. The fixed orifice, servo valve including a servo valve orifice and electrostatically controlled closure tabs, and a microbridge flow sensing device, are advantageously formed on a monolithic semiconductor chip mounted inside the housing. Significantly, a dielectric layer is deposited on a portion of the substrate surface surrounding the orifice formed therein to form the mesa and subsequently other dielectric and conductive layers are deposited with etching.

TL;DR: A fluid driving system for portable flow cytometers or other portable devices that accepts a less precise and less stable pressure source, and then adjusts the pressure in a closed-loop manner to maintain a constant, desired flow velocity is described in this article.