Until recently, the measurement of particle sizes in aerosols was largely a laboratory exercise. Currently, however, particulates in the atmosphere and in the industrial exhaust gases are being monitored extensively in the field. While the weight and volume of laboratory apparatus is seldom of concern, field work is often seriously hampered by equipment that is heavy or bulky. The diffusion batteries currently in use weigh in excess of fifty pounds and are often the heaviest piece of equipment in a test setup. For this reason, it was felt that the possibility of optimizing the dimensions of the battery for minimum weight should be investigated. The objectives of this study were: first, to analyze the relationship between the physical dimensions of the battery and operational parameters to determine if an optimum configuration exists, and second, to design a series of optimum weight batteries based upon the results of the study. The technical discussion which follows is limited to the first of these objectives. The theoretical foundation of the diffusion method has been extensively covered in the literature and is not considered here in detail. The design calculations for a specific series of batteries are included in the appendix.

Prepared under contract no. 68-02-1320, task 15, ROAP no. 21ADR-034, program element no. 1aB012. Issued Jan. 1977. Includes bibliographical references.