321-70250000 - Miller Smith 320 Series High Purity Two-Stage Stainless Steel Regulator, CGA 660, 0-50 PSI

Technical Overview: Miller Smith 320 Series High Purity Regulator

The Miller Smith 321-70-25-00-00 is a premium two-stage regulator from the 320 Silverline Series, engineered specifically for the precise control of corrosive and non-corrosive specialty gases. This unit is constructed from 316 stainless steel bar stock, ensuring high corrosion resistance and structural integrity under high-pressure conditions. The regulator features a CGA 660 inlet connection and is calibrated for a delivery pressure range of 0-50 PSIG, making it suitable for analytical and process applications requiring low-pressure stability.

At the core of this regulator is a convoluted stainless steel diaphragm that provides exceptional sensitivity and response to pressure changes. The design utilizes a metal-to-metal diaphragm seal, which is critical for maintaining maximum leak integrity—essential when handling hazardous or high-purity gases. The seat assembly includes a 316 stainless steel filter and PCTFE seating material, designed to protect the regulator from particulate contamination while ensuring a positive shut-off. The two-stage configuration effectively compensates for the decay in cylinder pressure, providing a constant delivery pressure without the need for frequent manual adjustments.

Safety and operational flexibility are key components of the 321-70-25-00-00 design. The bonnet features captured vent ports (1/16" FNPT) for both stages, allowing for the safe piping and venting of hazardous gases in the unlikely event of a diaphragm failure. Furthermore, the regulator is designed to withstand internal vacuums, facilitating effective purging operations during cylinder change-outs. Large 2-1/2 inch single scale gauges provide clear readability of both inlet and delivery pressures.

Key Technical Specifications

• Body Material: 316 Stainless Steel Bar Stock
• Diaphragm: Convoluted Stainless Steel
• Inlet Connection: CGA 660 (Stainless Steel)
• Delivery Range: 0-50 PSIG
• Max Inlet Pressure: 3500 PSIG
• Leak Integrity: Metal-to-metal seal design