| 摘要 |
<p>A monolithic flow controller for controlling the rate at which a medicinal liquid is administered to a patient. The monolithic flow controller includes one or more virtual valves that, because of their relatively small opening size (less than 0.5 mum in diameter), only permit fluid to flow through the valve 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 is monitored using two pressure sensors 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 the device is equal to the product of the differential pressure and the conductance of the channel in the flow controller. A capacitive bubble sensor is optionally provided to detect bubbles in the medicinal liquid being administered to the patient. The flow controller can be made 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 medicinal liquid can be contained within an integral pressurized fluid reservoir, administered by gravity feed, or conveyed by a pump to an inlet port of the flow controller.</p> |
