The Quad-Track Diffusion Dryer was designed to produce dry stable aerosols. The Dryer has four aerosol paths, each one encapsulated in desiccant beads, in a cylindrical body. The end caps are machined with NPT (National Pipe Thread) fittings for connecting the aerosol line fittings. This effectively lengthens residence time and the efficiency of the diffusion process is enhanced by increasing the available surface area of the desiccant. Comparison tests between the Single-Path and Quad-Track diffusion dryers have been conducted using three types of nebulizers. Filter samples collected from upstream and downstream locations relative to the Quad-Track Dryer showed there were minimal particle losses as a result of sedimentation, diffusion or impaction. The results of this test are detailed in "Design and Evaluation of the Lovelace Quad-Track Diffusion Dryer".
The Quad-Track Diffusion Dryer is 13" and 3.250" in diameter. There is a fitting on the side of the main body tube that is used for filling and emptying of the desiccant beads. When the beads become wet they should be removed from the dryer tube and spread out on a cookie sheet and placed in an oven for drying. They can also be placed on the cookie sheet and set out to air dry.