| 摘要 |
A miniature flow controller housing a fluid inlet and a fluid outlet, with the inlet pressure exceeding the outlet pressure. The outlet has orifices defined in a crystalline silicon membrane, along crystal planes of the silicon so that the geometry of the orifices is precisely known. The inlet and outlet are throttled by poppets which can seal the orifices on command of a device controller. The poppets are driven by shape retentive membranes which have two states, an open state and a closed state with a state change caused by application of small amounts of current to a resistive element in contact with the membrane. Rapid actuation of the poppets causes operation of the valve in a pulse mode. Where the fluid is a gas, pressure and temperature transducers measure conditions inside of the housing for application of gas law principles. By recording instantaneous pressure and temperature in the chamber, as the poppets are actuated, mass flow through the outlet orifices of the chamber is computed. |
