A high-flow thermopneumatic microvalve with improved efficiency and integrated state sensing
A high-flow thermopneumatic microvalve with improved efficiency and integrated state sensing
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DOI：
10.1109/jmems.2002.808459
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发表时间：
2003-04-01
影响因子：
2.7
通讯作者：
Wise, KD
中科院分区：
文献类型：
--
作者：
Rich, CA;Wise, KD
本文报道了一种具有波纹隔膜的热气动微型阀。隔膜下方的密封腔含有挥发性流体，通过电阻加热可以增加其蒸气压以使隔膜偏转，从而关闭阀门。硅加热器网格高出腔体地板 9 点，并且腔体仅部分填充流体，以提高热效率。地板上的真空密封电容式压力传感器可以直接监测腔体压力。戊烷填充执行器可在 500 mW 输入功率下维持高于大气压 2070 托的压力。现场测试的设备在 1000 托入口压力（排气至真空）下以 350 mW 关闭，并以 30 mW 输入保持关闭。阀门在 1500 托压差下传导 400 sccm，同时保持泄漏率低至 10(-3) sccm，产生 10(5) 的动态范围。我们已经开发出一种热力学模型，可以将实验功率、压力和瞬态响应数据的匹配度控制在几个百分点之内。该模型用于建议一种优化结构，能够在 50 mW 输入和响应时间下实现 2000 托的压力上升。玻璃和硅阀结构适合集成到完整的微流体系统中。
This paper reports a thermopneumatic microvalve featuring a corrugated diaphragm. A sealed cavity below the diaphragm contains a volatile fluid, the vapor pressure of which can be increased by resistive heating to deflect the diaphragm, thus closing the valve. Silicon heater grids are elevated 9 pm above the cavity floor, and the cavity is only partially filled with fluid, to increase thermal efficiency. A vacuum-sealed, capacitive pressure sensor on the floor allows direct monitoring of the cavity pressure. Pentane-filled actuators sustain a 2070 torr pressure rise above atmospheric with 500 mW input power. A device tested in situ closes with 350 mW at 1000 torr inlet pressure (venting to vacuum) and maintains closure with 30 mW input. Valves conduct 400 sccm under 1500 torr differential pressure, while maintaining leak rates as low as 10(-3) sccm, yielding a dynamic range of 10(5). A thermodynamic model has been developed that matches experimental power, pressure, and transient response data to within a few percent. This model is used to suggest an optimized structure capable of a 2000 torr pressure rise with 50 mW input and as response time. The glass-and-silicon valve structure is suitable for integration into complete microfluidic systems.