Nebulizers flow-shear

Five basic nebulizer designs, known to be used on ICP systems are cross flow, concentric, flow shear, ultrasonic, and FAA. The cross flow and concentric designs are most commonly supplied with commercial systems. FAA nebulizers were supplied with early multi-element systems and there are some commercial suppliers who provide ultrasonic nebulizers. 

The flow-shear nebulizer consists of a spherical surface with a fine slot through which the argon gas passes horizontally, and creates an aerosol stream flowing normal to the tangent at the slot. The Babington flow-shear nebulizer has been used for FAA, by Fry and Denton(36). The Fry and Denton version requires a flow rate of nine to twelve liters per minute of nebulizing gas. It may be possible to select a proper orifice size to obtain adequate aerosol production with a nebulizing gas flow rate of one liter per minute which is more suited to most ICP systems. A peristaltic pump transfers the solution to the nebulizer. 

Three common types of nozzle are shown diagrammatically. Types A and K are similar, with sharp cutoffs on the ends of the outer and inner capillaries to maximize shear forces on the liquid issuing from the end of the inner tube. In types K and C, the inner capillary does not extend to the end of the outer tube, and there is a greater production of aerosol per unit time. These concentric-tube nebulizers operate at argon gas flows of about 1 1/min. 

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