| 摘要 |
A fluid mass flow control apparatus, particularly useful for controlling low flow rates of fluids used in semiconductor manufacturing processes, comprises a first elongated flow tube connected to an inlet fitting and to a capsule like valve housing and a second elongated tube connected to the inlet fitting and the valve housing and including a flow sensor. The valve housing is connected to a magnetostrictive actuator including an elongated actuator member disposed in a conduit connected to the valve housing and serving as part of the fluid flow path through the apparatus. An electromagnetic coil is disposed about the conduit and the actuator and is responsive to energization to effect controlled elongation of the actuator to control the position of a valve closure member disposed in the valve housing. Adjustments to full-scale flow ranges of the apparatus may be obtained by inserting a tube or wire in the flow sensor tube to act as a flow restrictor.
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