Abstract: A portable microbial gaseous-fluid sampler includes a gaseous-fluid flow system at least partially supported by a structure. The gaseous-fluid flow system includes a gaseous-fluid intake portion having an intake port, a blower in fluid communication with the intake port, and a gaseous-fluid exhaust portion having an exhaust port. The sampler can further include an exhaust filter operable to substantially filter a totality of the gaseous fluid flowing through the sampler prior to exhausting the gaseous fluid. The sampler also can include a control system operable to control at least gaseous-fluid flow through the sampler, and a remote sampling head.

Abstract: The forward light scattering photometer for analyzing particles dispersed in a fluid includes a cylindrical housing enclosing a pair of axially spaced, spherical-surfaced, bi-convex lenses which provide axial focusing of the lamp image in an intermediate light scattering chamber through which the sample being analyzed is flowed. Such lenses provide axial focusing with no circumferential aberations and only radial aberations. Light traps having radial borders, such as semicircular blank off discs, are located on the upstream or lamp side of each lens to provide an image having sharp radial edges, thereby eliminating the need for high quality lenses adapted to correct for spherical aberations.The lenses are shielded from contamination by particles from the sample by a stream of purge air introduced into the housing at a location near each lens and tangentially with the housing bore so as to create a stable vortexing flow of the purge air in the vicinity of each lens.