| 摘要 |
<p>A monolithic flow controller (10) for controlling the rate at which a medicinal liquid (14) is administered to a patient. The monolithic flow controller (10) includes one or more virtual valves (26) that, because of their relatively small opening size (less than 0.5 .mu.m in diameter), only permit fluid to flow through the valve (26) when a forward bias voltage is applied. If a reverse bias voltage or no voltage is applied, fluid flow through the opening is inhibited. The fluid rate through the device (10) is monitored using two pressure sensors (38, 40) or a differential pressure sensor that determine the differential pressure along the flow path through the device or relative to the external ambient pressure. The flow through th e device is equal to the product of the differential pressure and the conductance of the channel (24) in the flow controller. A capacitive bubble sensor (34, 36) is optionally provided to detect bubbles in the medicinal liquid being administered to the patient. The flow controller (10) can be ma de sufficiently small to be injected into a patient's cardiovascular system or other portion of the patient's body through a hypodermic syringe and needle, or it can be implanted in the patient's body at a desired site. The medicina l liquid (14) can be contained within an integral pressurized fluid reservoir (12), administered by gravity feed, or conveyed by a pump to an inlet port (16) of the flow controller (10).</p> |
