321-66250000 - Miller Smith 320 Series High Purity Two-Stage Stainless Steel Regulator CGA 660

High Purity Engineering for Corrosive Environments

The Miller Smith 321-66-25-00-00 is a premium component of the 320 Silverline Series, engineered specifically for the rigorous demands of high-purity and corrosive gas regulation. This two-stage regulator is constructed from 316 stainless steel bar stock, ensuring that all wetted parts—including the body and the convoluted diaphragm—offer maximum resistance to chemical attack. The utilization of PCTFE (Polychlorotrifluoroethylene) for the seat material further enhances the unit's compatibility with aggressive media while maintaining a reliable seal over an extended service life. The metal-to-metal diaphragm seal is a critical design feature, providing superior leak integrity compared to elastomeric seals, which is essential when handling hazardous or expensive specialty gases.

Functionally, the two-stage architecture of this regulator ensures an exceptionally stable delivery pressure. As the cylinder pressure decays, single-stage regulators often exhibit a rise in outlet pressure; however, the 321-66-25-00-00 compensates for these inlet fluctuations, delivering a constant 0-50 PSIG output. This stability is vital for analytical instrumentation and precise process control where pressure variance cannot be tolerated. The unit is also designed with safety and integration in mind, featuring a captured vent port (1/16" FNPT) in the bonnet. This allows users to pipe vented gases away to a safe location in the rare event of a diaphragm failure, a mandatory safety protocol for many hazardous gas applications.

The regulator is equipped with large, 2-1/2 inch single-scale gauges that provide clear readability of both inlet and delivery pressures. The design accommodates internal vacuums, making it suitable for purge cycles essential in maintaining high-purity gas lines. Note that for hazardous gas service, a Cross Purge Assembly is recommended to ensure effective removal of atmospheric contaminants or hazardous residues during cylinder change-outs. With a maximum inlet pressure rating of 3500 PSIG and a CGA 660 connection, this device is tailored for specific corrosive gas cylinders requiring robust, leak-proof connection standards.