Abstract: A particle counter of the condensation nucleus type wherein a primary stream of fluent material containing particles enlarged by vapor condensate of a working fluid flow through a viewing volume. A secondary stream of fluent material, termed purge gas, surrounds the primary stream of fluent material as the primary stream traverses the view volume, thereby providing a boundary layer of fluent material, reducing turbulence of the primary stream. The two streams are merged after passing through the view volume and the merged stream is drawn into one or more coalescent filters for conversion of vapor to working fluid which is then recycled for reuse, thereby extending the life of the working fluid and preventing escape of vapor which might contaminate the ambient environment.

Abstract: A condensation nucleus counter features an entropy control mechanism to regulate the entropy of a vaporized fluid present in a saturator, thereby facilitating supersaturation of the same about particulates entrained in a sample gas stream before the same passes through a condenser. The condensation nucleus counter includes a supply of sample gas, conduits adapted to allow the sample gas stream to flow therethrough, a saturator, a condenser and an optical detector, all of which are in fluid communication with each other. The manifold is disposed between the conduit and the saturator, and also a temperature control device. The manifold comprises a feed chamber and a plurality of channels positioned so that the sample gas stream entering the feed chambers evenly divides into a plurality of flows, with each flow entering the saturator. The temperature control device regulates the temperature difference between the flows entering the saturator and the vaporized fluid contained so as to be within a specified range.