Ultrasonically actuated needle pump system
An ultrasonically driven pump, which may be used for sampling body fluids or atomizing liquids, has a stationary outer needle and an inner needle mounted within the bore of the outer needle. The distal end of the inner needle is positioned adjacent to the distal end of the outer needle. The inner needle is ultrasonically vibrated by an ultrasonic actuator without vibrating the outer needle, with resulting draw of liquid through the distal end of the outer needle into the bore of the inner needle for discharge through the proximal end of the inner needle. The outer needle can be formed to have a penetrating tip suited for penetrating the skin of a subject to allow sampling of body fluids including interstitial fluids. The pump can also be used for atomizing liquid, by drawing liquid from a supply that is pumped from the distal end to an open proximal end of the inner needle where the liquid is discharged by atomization into the atmosphere.
1. A method of atomizing a liquid comprising:
(a) inserting the distal end of an outer needle with a hollow bore into a supply of liquid to be atomized;
(b) ultrasonically vibrating an inner needle mounted within the bore of the outer needle, the inner needle having a hollow bore and a distal end and a proximal end, the distal end of the inner needle located adjacent to spaced inwardly from and completely surrounded by the distal end of the outer needle, to draw liquid by the vibration of the inner needle from die distal end of the inner needle to the proximal end of the inner needle where it is discharged by atomization into the atmosphere.