Designed for pressure and drain applications processing ultra pure water and highly corrosive chemicals. The valve is ideal for a wide range of uses, from pharmaceutical to semiconductor in PTFE, Kynar PVDF or Polypro body materials; car washes to chemical plants in the lower-cost Geon PVC body materials, and higher temperatures in those applications with Corzan CPVC bodies.
For high purity applications such as deionized water, Series BSDA provides the ultimate in non-leaching, contamination-free sealing. The standard valves are air pressure to open, with "fail safe" spring return to close. Because the diaphragm is attached to the piston, no inlet pressure is required to assist with opening. The BSDA is not designed for vacuum service.
Discontinued Series BSD was an earlier design with a non-attached diaphragm. Series BSDA and former Series BSD are identical in all other respects. Series BSDA supersedes Series BSD
Diaphragm Design
The standard diaphragm material is PTFE for the ultimate in purity, backed with FKM for the ultimate in strength and flexibility. The FKM side is not in contact with liquid.
Materials of Construction
Wetted body materials available standard are Geon ® PVC, Corzan ® CPVC, PTFE, Kynar ® PVDF, and Natural Unpigmented Polypropylene. Other body materials and custom materials may be available, depending on costs and/or quantity.
Compact air cylinder head standard material is Geon PVC, regardless of the body material. Seals used for cylinder are Buna-N. Spring is steel; fasteners are stainless steel. None of these materials contact liquid. If for some reason these are not acceptable for your application, other air section materials can be provided depending on costs and/or quantity.
Operation
A 3-way air solenoid valve connected to the 1/8" NPT port on the air cylinder head is required to actuate the diaphragm valve. When air pressure (40 to 100 psi) is applied, the diaphragm valve opens. Consult the table below for complete air specifications. When the air pressure is vented away through the 3-way air solenoid valve, the internal spring automatically closes the diaphragm. (This is referred to as "normally-closed, air-to-open/spring return valve). The spring is not in contact with liquid. It is recommended that filtered, lubricated compressed air be used.
The cylinder head features multiple seals, in addition to the main diaphragm seal in contact with the liquid. There is a vent located between two seals (above the main diaphragm, below the cylinder head u-cups) that will "weep" in the event of a primary seal failure. The valve will still function, under pressure, without metal contacting liquid. This is the patented Plast-O-Matic Fail-Dry ® , which adds an additional layer of "protection" for your process.
Piping Connections
The standard valves are precision machined from the highest quality brand thermoplastic bar stock with female NPT connections. Spigot connections are also available. For orders of 25 or more valves, connections can be provided with male threads, sockets, unions, etc.
Applications
Series BSDA PTFE diaphragm valves have been used successfully in Semiconductor fabs, pharmaceutical processing, deionized water, chemical processing, potable water treatment, chemical injection systems, battery filling, wastewater treatment, dialysis systems, and many other applications since it was introduced in 1984. This is a proven design for high purity processes, providing 1,000,000 cycles in normal use. |
